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PSim Home > York Corpus Christi Play [ Staging | Contexts | Origin | Glossary ] |Introduction Contexts Chronology||For an historical anecdote illustrating how the religious, economic, and civic life of the medieval Christian were inextricably linked, read "A Christ Taken Prisoner" The outdoor theatrical event in the medieval city of York, England, known to its performers and audiences as the "Corpus Christi Play," is a collection of brief religious plays that together represent the story of Christian salvation. The York cycle is one of four that have survived in more or less complete form. The others are known as Chester, Wakefield, (after the cities where they were performed) and N-Town (now identified with no known city, but formerly identified as Townley). The York cycle was performed nearly every year, on the feast of Corpus Christi (Latin for the Body of Christ). The plays were already an established tradition in the late 14th century, and they continued in one form or other (weakened by Protestant censorship) until the mid-to-late 16th century. Nobody knows who wrote the plays, or even how many authors there were, although the group of plays describing the Passion seems to bear the stamp of an exceptional dramatist now called "the York Realist." The plays date from the time before England's separation from the Church of Rome; as such, they emphasize the sacraments and rituals of the Catholic faith and urge people to salvation through active membership and participation in the community of worshippers. Since the plays were performed as part of a day-long celebration of Corpus Christi -- the presence of the Body of Christ in the sacrament of the Eucharist -- they upheld the authority of the Church as a theological and moral guide for living in this world and the next. To begin to understand the popularity and significance of the Corpus Christi plays, we must first recognize the significance of the feast being celebrated. During the early middle ages, as church architecture and artistry moved away from the con

rship) until the mid-to-late 16th century. Nobody knows who wrote the plays, or even how many authors there were, although the group of plays describing the Passion seems to bear the stamp of an exceptional dramatist now called "the York Realist." The plays date from the time before England's separation from the Church of Rome; as such, they emphasize the sacraments and rituals of the Catholic faith and urge people to salvation through active membership and participation in the community of worshippers. Since the plays were performed as part of a day-long celebration of Corpus Christi -- the presence of the Body of Christ in the sacrament of the Eucharist -- they upheld the authority of the Church as a theological and moral guide for living in this world and the next. To begin to understand the popularity and significance of the Corpus Christi plays, we must first recognize the significance of the feast being celebrated. During the early middle ages, as church architecture and artistry moved away from the conservatism necessitated by its beginnings as a renegade faith in a Pagan world, and as the rituals surrounding Christian worship grew more intricate, the interior design of churches evolved. As the churches grew in size, the altar grew more elaborate, and the people moved proportionately farther away from it; communion rails developed because it was inconvenient to have crowds rushing the ornate altars to receive the Host. These rails eventually developed into a screen of bars or wooden slats, behind which the priest would say the mass. In addition, the priest and the congregation both faced the tabernacle on the back wall, the end result being that the priest blocked the people's view of most of the mass. Over generations, the faithful began to associate the unseen elements of the service with an air of mystery. Only when the priest lifted the consecrated wine and bread over his head in prayer -- a gesture known as the Elevation -- did the people get a clear view of the action. In the cities people ran from c

servatism necessitated by its beginnings as a renegade faith in a Pagan world, and as the rituals surrounding Christian worship grew more intricate, the interior design of churches evolved. As the churches grew in size, the altar grew more elaborate, and the people moved proportionately farther away from it; communion rails developed because it was inconvenient to have crowds rushing the ornate altars to receive the Host. These rails eventually developed into a screen of bars or wooden slats, behind which the priest would say the mass. In addition, the priest and the congregation both faced the tabernacle on the back wall, the end result being that the priest blocked the people's view of most of the mass. Over generations, the faithful began to associate the unseen elements of the service with an air of mystery. Only when the priest lifted the consecrated wine and bread over his head in prayer -- a gesture known as the Elevation -- did the people get a clear view of the action. In the cities people ran from church to church to see the elevated Host as often as possible, since they assumed that the more Elevations you saw, the more grace you would acquire. At the end of the twelfth century, stories began to circulate of miracles that had occurred at the moment of Elevation -- people had seen visions, the Host shone like the sun, a tiny child had appeared in the priest's hands, and so forth. In some congregations the majority of the faithful waited for the ringing of the sance-bell, which signaled the approaching consecration, before they even deigned to enter the church, and then, as soon as the Elevation was concluded rushed out again as quickly as they had come in. People started lawsuits to ensure that they obtained pews which provided a favourable view of the altar, and some priests even took bribes to protract the Elevation. (Harris 75)To address this growing problem, in 1264, Pope Urban IV suggested a new religious celebration that would bring the consecrated host out into the streets so that those who wishe

hurch to church to see the elevated Host as often as possible, since they assumed that the more Elevations you saw, the more grace you would acquire. At the end of the twelfth century, stories began to circulate of miracles that had occurred at the moment of Elevation -- people had seen visions, the Host shone like the sun, a tiny child had appeared in the priest's hands, and so forth. In some congregations the majority of the faithful waited for the ringing of the sance-bell, which signaled the approaching consecration, before they even deigned to enter the church, and then, as soon as the Elevation was concluded rushed out again as quickly as they had come in. People started lawsuits to ensure that they obtained pews which provided a favourable view of the altar, and some priests even took bribes to protract the Elevation. (Harris 75)To address this growing problem, in 1264, Pope Urban IV suggested a new religious celebration that would bring the consecrated host out into the streets so that those who wished to gaze and meditate upon it could have their fill without disrupting the other business of the mass. This joyful celebration, which began to establish itself about 50 years later, served as an important counterpoint to the medieval obsession with the sinful state of fallen humanity; it was an opportunity for the "good Christian" to reflect upon the promises of Christ, not merely upon the consequences of human sin. The Mass, in Urban's words, should be a "glorious act of remembrance, which fills the minds of the faithful with joy at their salvation and mingles their tears with an outburst of reverend jubilation." Medieval drama served as a religious outlet; and, in an age when most people were illiterate, took an important place alongside stained glass windows and statues in spreading the Christian message to the general public. For instance, the play depicting the birth of Christ includes a long monologue delivered by a learned man directly to the audience-- it is a sermon explaining the significance of Ol

d to gaze and meditate upon it could have their fill without disrupting the other business of the mass. This joyful celebration, which began to establish itself about 50 years later, served as an important counterpoint to the medieval obsession with the sinful state of fallen humanity; it was an opportunity for the "good Christian" to reflect upon the promises of Christ, not merely upon the consequences of human sin. The Mass, in Urban's words, should be a "glorious act of remembrance, which fills the minds of the faithful with joy at their salvation and mingles their tears with an outburst of reverend jubilation." Medieval drama served as a religious outlet; and, in an age when most people were illiterate, took an important place alongside stained glass windows and statues in spreading the Christian message to the general public. For instance, the play depicting the birth of Christ includes a long monologue delivered by a learned man directly to the audience-- it is a sermon explaining the significance of Old Testament prophecies that point to the Nativity. The speaker ensures that the audience understands everything they need to know in order to appreciate more fully the significance of the events that the actors are about to portray. The actors then, become living icons, windows into the spiritual realm, which never seemed very far off to the medieval mind. During the early part of the Corpus Christi period, the Corpus Christi plays were part of a larger celebration on the feast of Corpus Christi. The community leaders, including the religious authorities, the elected town officials, and the masters of the guild, assembled for a pre-dawn torchlight procession in honor of the Body of Christ-- a consecrated host was carried at the head of the procession. The play wagons would follow behind. The York pageant was completely interwoven into society. Throughout the year, the elected officials -- known as the City Fathers -- used the York play as a way for the local government to regulate business. For instance, when

d Testament prophecies that point to the Nativity. The speaker ensures that the audience understands everything they need to know in order to appreciate more fully the significance of the events that the actors are about to portray. The actors then, become living icons, windows into the spiritual realm, which never seemed very far off to the medieval mind. During the early part of the Corpus Christi period, the Corpus Christi plays were part of a larger celebration on the feast of Corpus Christi. The community leaders, including the religious authorities, the elected town officials, and the masters of the guild, assembled for a pre-dawn torchlight procession in honor of the Body of Christ-- a consecrated host was carried at the head of the procession. The play wagons would follow behind. The York pageant was completely interwoven into society. Throughout the year, the elected officials -- known as the City Fathers -- used the York play as a way for the local government to regulate business. For instance, when the merchant guild imported leather, impinging on the tanners' livelihood, the merchants were ordered by the city officials to pay a fine; half of the fine went to the city, and the other half went to pay the tanners' expenses for mounting the next year's pageant. Similarly, if a guild defaulted on a play, caused delays or disorder in the procession, or if a clergyman or burgher failed to show up to take his part in the procession, fines for these infractions went to the next year's production. In the York plays the past is a direct continuation of the present: Moses swears by the cross; Pilate calls his soldiers knights; everyone wears medieval garb. No attempt was made to hide this anachronism because nobody minded -- medieval people did not think of the world of the Bible as different from their own. Because each play was produced by a guild, there was a competition among the guilds to produce the best play. The guilds were economic, social and often religious groups, tied together in that unique medieval

the merchant guild imported leather, impinging on the tanners' livelihood, the merchants were ordered by the city officials to pay a fine; half of the fine went to the city, and the other half went to pay the tanners' expenses for mounting the next year's pageant. Similarly, if a guild defaulted on a play, caused delays or disorder in the procession, or if a clergyman or burgher failed to show up to take his part in the procession, fines for these infractions went to the next year's production. In the York plays the past is a direct continuation of the present: Moses swears by the cross; Pilate calls his soldiers knights; everyone wears medieval garb. No attempt was made to hide this anachronism because nobody minded -- medieval people did not think of the world of the Bible as different from their own. Because each play was produced by a guild, there was a competition among the guilds to produce the best play. The guilds were economic, social and often religious groups, tied together in that unique medieval way. Within the plays are obvious and more subtle mercantile messages. For instance, the play of the construction of Noah's ark was produced by the wainwrights, or shipbuilders; Noah was probably played by a well-known shipbuilder, employing his craft with talent on loan from God. In the play put on by the cloth dyers, Jesus is dressed in white, which one of the mockers calls the color of fools -- suggesting, in essence, the audience members are fools unless they pay to have their clothing dyed. The winesellers did the (now lost) Wedding Feast of Cana, the Bakers did the Last Supper, and the Chaundlers -- who made candles and chandeliers -- did the play with the Star of Bethlehem. The Mercer's wagon for the play "Doomsday" included special effects -- a pulley-operated platform that Christ rides up and down from heaven; smoke for a gaping hell mouth, into which the sinners were thrown; miniature angels that seemed to run around the heavens in a circle; and of course, costumes, music, and a choir of voices. Al

way. Within the plays are obvious and more subtle mercantile messages. For instance, the play of the construction of Noah's ark was produced by the wainwrights, or shipbuilders; Noah was probably played by a well-known shipbuilder, employing his craft with talent on loan from God. In the play put on by the cloth dyers, Jesus is dressed in white, which one of the mockers calls the color of fools -- suggesting, in essence, the audience members are fools unless they pay to have their clothing dyed. The winesellers did the (now lost) Wedding Feast of Cana, the Bakers did the Last Supper, and the Chaundlers -- who made candles and chandeliers -- did the play with the Star of Bethlehem. The Mercer's wagon for the play "Doomsday" included special effects -- a pulley-operated platform that Christ rides up and down from heaven; smoke for a gaping hell mouth, into which the sinners were thrown; miniature angels that seemed to run around the heavens in a circle; and of course, costumes, music, and a choir of voices. Although scholars used to think that all of society revolved around the guilds, the guild structure was largely undeveloped before the Black Death (14c). Modern Marxists imagined the guilds were labor organizations, developed by the rising working class to protect their economic and political rights. More recent research suggests that the guilds were formed by the city officials in order to organize and control various conflicting business interests. They were run not by workers but by the bosses -- master guildsmen who controlled who was hired and who got training; these masters aspired to be landlords and city officials, and moved freely in these circles. For the few at the top of the guild structure, the York Play might have been part of a class struggle being waged in the city. The working class did have its own organizations, called "Fraternities." These were similar to the modern JayCees, Knights of Columbus or Shriners; they were attached to a specific parish and focusing on charity -- an enormous amount

though scholars used to think that all of society revolved around the guilds, the guild structure was largely undeveloped before the Black Death (14c). Modern Marxists imagined the guilds were labor organizations, developed by the rising working class to protect their economic and political rights. More recent research suggests that the guilds were formed by the city officials in order to organize and control various conflicting business interests. They were run not by workers but by the bosses -- master guildsmen who controlled who was hired and who got training; these masters aspired to be landlords and city officials, and moved freely in these circles. For the few at the top of the guild structure, the York Play might have been part of a class struggle being waged in the city. The working class did have its own organizations, called "Fraternities." These were similar to the modern JayCees, Knights of Columbus or Shriners; they were attached to a specific parish and focusing on charity -- an enormous amount of which was needed in the days before large-scale government social programs. To modern Christians, the term "religious theater" tends to conjure up images of terrified but cute kids wearing dishtowels on their heads at Christmas time, or silly-looking adults playing guitars and singing with puppets. Because the feast being celebrated is named for the body of Christ, the York plays emphasize the importance of that body, dwelling on its actions, its symbolic significance, and, of course, its death and resurrection. Many Protestants will be uncomfortable with the play's presentation of Christ's suffering, as well as the implied and direct significance of "the body of Christ" and its relationship to the bread and wine offered during Christian worship. A colleague of mine recently rolled his eyes and moaned in mimicry of traditional paintings of Christ's passion, calling such images "offensive" to an Evangelical Protestant mindset. During the Reformation, all artistic reminders of the medieval church, and the p

of which was needed in the days before large-scale government social programs. To modern Christians, the term "religious theater" tends to conjure up images of terrified but cute kids wearing dishtowels on their heads at Christmas time, or silly-looking adults playing guitars and singing with puppets. Because the feast being celebrated is named for the body of Christ, the York plays emphasize the importance of that body, dwelling on its actions, its symbolic significance, and, of course, its death and resurrection. Many Protestants will be uncomfortable with the play's presentation of Christ's suffering, as well as the implied and direct significance of "the body of Christ" and its relationship to the bread and wine offered during Christian worship. A colleague of mine recently rolled his eyes and moaned in mimicry of traditional paintings of Christ's passion, calling such images "offensive" to an Evangelical Protestant mindset. During the Reformation, all artistic reminders of the medieval church, and the public's lingering attachment to them, constituted grave threats to the new Protestant order, prompting Protestant reformers to act quickly to suppress them (see Eamon Duffy, The Stripping of the Altars: Traditional Religion in England c. 1400-1580). As a result, many protestant denominations have all but lost what was once a popular and powerful devotional tradition: affective piety -- a religious zeal which affects the emotions, by way of statues, images, and devotional legends which expound upon core religious messages. (See "Affective Piety," below). Every Easter in the Philippines, pious volunteers carry crosses through the streets and actually allow themselves to be temporarily crucified (with stainless steel nails sterilized in alcohol) in order to fully understand the grief and pain which Jesus underwent on the cross. Religious devotion which encourages the faithful to meditate deeply upon the physical and emotional sufferings of holy figures is called "affective piety." The Philippines example may be

ublic's lingering attachment to them, constituted grave threats to the new Protestant order, prompting Protestant reformers to act quickly to suppress them (see Eamon Duffy, The Stripping of the Altars: Traditional Religion in England c. 1400-1580). As a result, many protestant denominations have all but lost what was once a popular and powerful devotional tradition: affective piety -- a religious zeal which affects the emotions, by way of statues, images, and devotional legends which expound upon core religious messages. (See "Affective Piety," below). Every Easter in the Philippines, pious volunteers carry crosses through the streets and actually allow themselves to be temporarily crucified (with stainless steel nails sterilized in alcohol) in order to fully understand the grief and pain which Jesus underwent on the cross. Religious devotion which encourages the faithful to meditate deeply upon the physical and emotional sufferings of holy figures is called "affective piety." The Philippines example may be extreme; however, affective piety was an important part of medieval religious instruction, designed to stir the personal devotion of people living in a society that took religion for granted. In their private chambers, using a picture, a statue, or spoken prayers to feed their spiritual imagination, the devout entered into the suffering of Christ, a martyr or some other holy figure with a psychological totality that we today would probably describe as a very extreme form of method acting. Many modern Christians may be tempted to dismiss or ridicule such devotional practices, yet these same critics may have no problem with the idea of responding with powerful emotion to contemporary religious music or extemporaneous spoken prayer. Meanwhile secular culture provides many opportunities for people to cry over the imaginary troubles of soap opera characters, or to cheer or curse a televised sporting event. In the absence of television or recorded sound, the medieval faithful responded in much the same way to icons

extreme; however, affective piety was an important part of medieval religious instruction, designed to stir the personal devotion of people living in a society that took religion for granted. In their private chambers, using a picture, a statue, or spoken prayers to feed their spiritual imagination, the devout entered into the suffering of Christ, a martyr or some other holy figure with a psychological totality that we today would probably describe as a very extreme form of method acting. Many modern Christians may be tempted to dismiss or ridicule such devotional practices, yet these same critics may have no problem with the idea of responding with powerful emotion to contemporary religious music or extemporaneous spoken prayer. Meanwhile secular culture provides many opportunities for people to cry over the imaginary troubles of soap opera characters, or to cheer or curse a televised sporting event. In the absence of television or recorded sound, the medieval faithful responded in much the same way to icons, statues, or music or dialogue from live performers. For more on affective piety, see "'Crucifye hem, Crucifye hem': The Subject and Affective Response in Middle English Passion Narratives", by Laurelle LeVert (a former classmate of mine). June, 1997 -- first published in (Re)Soundings 16 Jul 1999 -- updated for UWEC May 2003 -- updated for Seton Hill University PSim Home > York Corpus Christi Play [ Staging | Contexts | Origin | Glossary ]

, statues, or music or dialogue from live performers. For more on affective piety, see "'Crucifye hem, Crucifye hem': The Subject and Affective Response in Middle English Passion Narratives", by Laurelle LeVert (a former classmate of mine). June, 1997 -- first published in (Re)Soundings 16 Jul 1999 -- updated for UWEC May 2003 -- updated for Seton Hill University PSim Home > York Corpus Christi Play [ Staging | Contexts | Origin | Glossary ]

Surface plasmon polaritons are collective longitudinal oscillations of electrons near a material surface, strongly coupled to an electromagnetic wave. The existence of coherent electron oscillations bound to the surface of a conductor were first predicted by Ritchie in 1957 and demonstrated by Powell and Swan[2,3] in 1959, but have recently experienced an explosion of interest due to their ability to efficiently manipulate light on a deep sub-wavelength scale. Because the electromagnetic wave is coupled to the motion of conduction band electrons bound to the material surface, the fields are strongly localized to the surface, opening up possibilities of sub-wavelength optical detectors and waveguides; compact, sensitive chemical detectors; and enhanced light-matter interaction. |Fig. 1: Dispersion relation for bulk plasmons, free-space electromagnetic waves, and surface plasmons.| Both bulk and surface plasmons have associated electromagnetic waves, and can consequently be described by Maxwell's equations. The coherent oscillations of electron motion can be encapsulated in the dielectric constant of the material. The derivation of the electromagnetic fields which characterize bulk and surface plasmons is done below, and those interested are encouraged to work out the results. To keep things brief however, the basic form of the bulk and surface plasmon solutions are shown below, along with a plot of the dispersion relation for these modes. The dispersion diagram relates the time-variation of the wave (given by its frequency &omega) to the spatial variation of the wave (given by its wave-vector kx). Bulk plasmons are associated with purely transverse electromagnetic waves, with the electric and magnetic fields perpendicular to the direction of propagation, and can only exist for &omega > &omegap (the plasma frequency). &omegap is the resonant frequency of free electrons in response to a perturbation (such as an electromagnetic field). For &omega < &omegap, the wave-vector for bulk plasmons becomes imaginary, giving

coherent oscillations of electron motion can be encapsulated in the dielectric constant of the material. The derivation of the electromagnetic fields which characterize bulk and surface plasmons is done below, and those interested are encouraged to work out the results. To keep things brief however, the basic form of the bulk and surface plasmon solutions are shown below, along with a plot of the dispersion relation for these modes. The dispersion diagram relates the time-variation of the wave (given by its frequency &omega) to the spatial variation of the wave (given by its wave-vector kx). Bulk plasmons are associated with purely transverse electromagnetic waves, with the electric and magnetic fields perpendicular to the direction of propagation, and can only exist for &omega > &omegap (the plasma frequency). &omegap is the resonant frequency of free electrons in response to a perturbation (such as an electromagnetic field). For &omega < &omegap, the wave-vector for bulk plasmons becomes imaginary, giving an exponentially decaying wave instead of a propagating wave. It is for this reason that most metals are highly reflective for visible light (&omega < &omegap &asymp 10eV), but transparent for ultraviolet light (&omega > &omegap) [4, pg. 275]. Surface plasmons have an associated electromagnetic wave with both transverse and longitudinal field components. Such waves can only be excited at the interface between a conductor and dielectric, and are tightly bound to the surface. The fields reach their maximum at the interface (z=0), and exponentially decay away from the surface. The wave-vector of the surface plasmon mode (kspp) always lies to the right of the free space wave-vector (ko), such that &lambdaspp < &lambdao, where &lambdaspp is the wavelength of the surface plasmon and &lambdao is the wavelength of light in free space (vacuum). Additionally, this makes it impossible to directly launch a surface plasmon wave by illumination with free-space radiation: the free-space photons simply do not have enough mom

an exponentially decaying wave instead of a propagating wave. It is for this reason that most metals are highly reflective for visible light (&omega < &omegap &asymp 10eV), but transparent for ultraviolet light (&omega > &omegap) [4, pg. 275]. Surface plasmons have an associated electromagnetic wave with both transverse and longitudinal field components. Such waves can only be excited at the interface between a conductor and dielectric, and are tightly bound to the surface. The fields reach their maximum at the interface (z=0), and exponentially decay away from the surface. The wave-vector of the surface plasmon mode (kspp) always lies to the right of the free space wave-vector (ko), such that &lambdaspp < &lambdao, where &lambdaspp is the wavelength of the surface plasmon and &lambdao is the wavelength of light in free space (vacuum). Additionally, this makes it impossible to directly launch a surface plasmon wave by illumination with free-space radiation: the free-space photons simply do not have enough momentum to excite the surface plasmon. As &omega increases, kspp gets larger and larger, moving further away from ko. As kspp increases, the surface plasmon wavelngth decreases and the wave is more tightly bound to the surface. This process has an upper limit of &omegasp, the surface plasmon resonant frequency, which occurs when the dielectric constant of the metal and the dielectric have the same magnitude but opposite signs. |Fig. 2: Schematic of a Kretschmann coupling setup for launching surface plasmons optically.| Surface plasmons were first predicted by Ritchie in 1957, and were experimentally verified by Powell and Swan[2,3] in 1959 with electron energy loss spectroscopy measurements. In these measurements, high energy electrons were used to bombard a thin metallic film and launch surface plasmons. The charge of the high energy electrons couples to the plasma oscillations of electrons in the metal; by tuning the energy and angle of incidence of the electrons, the wave-vector can be tuned and surface plas

entum to excite the surface plasmon. As &omega increases, kspp gets larger and larger, moving further away from ko. As kspp increases, the surface plasmon wavelngth decreases and the wave is more tightly bound to the surface. This process has an upper limit of &omegasp, the surface plasmon resonant frequency, which occurs when the dielectric constant of the metal and the dielectric have the same magnitude but opposite signs. |Fig. 2: Schematic of a Kretschmann coupling setup for launching surface plasmons optically.| Surface plasmons were first predicted by Ritchie in 1957, and were experimentally verified by Powell and Swan[2,3] in 1959 with electron energy loss spectroscopy measurements. In these measurements, high energy electrons were used to bombard a thin metallic film and launch surface plasmons. The charge of the high energy electrons couples to the plasma oscillations of electrons in the metal; by tuning the energy and angle of incidence of the electrons, the wave-vector can be tuned and surface plasmons of a whole range of wavelengths can be excited. However, due to the high energy of the electrons, they have a very large momentum and it is difficult to precisely control the coupling: even a slight spread in energy or angle will result in a very broad range of surface plasmon wavelengths being excited. Additionally, only surface plasmons far along the dispersion curve, where kspp is largest, are generally excited. A more precise method to launch surface plasmons is through coupling with an incident electromagnetic wave (photon). As mentioned previously, direct excitation of surface plasmons by free-space photons is not achievable because kspp is always greater than ko; this can be seen in figure 1, where the surface plasmon dispersion relation always lies to the right of the free space dispersion curve. This can be overcome by back-side illumination through a material with a higher index of refraction (n), where the far-field radiation has a larger wave-vector (k=nko). This type of coupling geometry is

mons of a whole range of wavelengths can be excited. However, due to the high energy of the electrons, they have a very large momentum and it is difficult to precisely control the coupling: even a slight spread in energy or angle will result in a very broad range of surface plasmon wavelengths being excited. Additionally, only surface plasmons far along the dispersion curve, where kspp is largest, are generally excited. A more precise method to launch surface plasmons is through coupling with an incident electromagnetic wave (photon). As mentioned previously, direct excitation of surface plasmons by free-space photons is not achievable because kspp is always greater than ko; this can be seen in figure 1, where the surface plasmon dispersion relation always lies to the right of the free space dispersion curve. This can be overcome by back-side illumination through a material with a higher index of refraction (n), where the far-field radiation has a larger wave-vector (k=nko). This type of coupling geometry is shown in figure 2, and is known as a Kretschmann-Raether coupler. A surface plasmon will be efficiently excited when k|| = nkosin(&theta) = kspp. Kretschmann couplers are commonly used in experiments, but are limited to very thin films such that the high-k photon is able to tunnel through the film and couple to a surface plasmon on the lower-index surface. A more general approach to launching surface plasmons with light is the use of structured surfaces that are able to impart momentum on the photon, enabling it to couple to the surface plasmon mode. Anything from a single sub-wavelength disk or slit, to rectangular or sinusoidal diffraction gratings are used for this type of coupling. A thorough overview of surface plasmon coupling and patterned and rough surfaces is given by Raether. Surface plasmons have many interesting applications such as optical measurements of films, chemicals, and biological agents bound to a metallic surface; confinement and guiding of light below the classical diffraction limit; an

shown in figure 2, and is known as a Kretschmann-Raether coupler. A surface plasmon will be efficiently excited when k|| = nkosin(&theta) = kspp. Kretschmann couplers are commonly used in experiments, but are limited to very thin films such that the high-k photon is able to tunnel through the film and couple to a surface plasmon on the lower-index surface. A more general approach to launching surface plasmons with light is the use of structured surfaces that are able to impart momentum on the photon, enabling it to couple to the surface plasmon mode. Anything from a single sub-wavelength disk or slit, to rectangular or sinusoidal diffraction gratings are used for this type of coupling. A thorough overview of surface plasmon coupling and patterned and rough surfaces is given by Raether. Surface plasmons have many interesting applications such as optical measurements of films, chemicals, and biological agents bound to a metallic surface; confinement and guiding of light below the classical diffraction limit; and enhanced light-matter interaction such as surface-enhanced Raman spectroscopy (SERS). A few of the more interesting applications from the literature and industry are outlined below. Surface plasmon resonance sensors based on Kretschmann couplers can be used to make precise optical measurements at a metal-dielectric interface. The basic idea behind these detectors is encapsulated in the coupling condition discussed above for the Kretschmann geometry: k|| = nkosin(&theta) = kspp. Since the surface plasmon is tightly bound to the metal-dielectric interface, any changes in that interface will translate directly into changes in the surface plasmon wave-vector kspp. This will cause a corresponding change in the optimal excitation angle for the Kretschmann coupler; by measuring this angle, the change in kspp can be deduced, allowing for the change in the refractive index to be computed. These detectors are sensitive enough that they can measure a change in film thickness of just a single monolayer, or refraction i

d enhanced light-matter interaction such as surface-enhanced Raman spectroscopy (SERS). A few of the more interesting applications from the literature and industry are outlined below. Surface plasmon resonance sensors based on Kretschmann couplers can be used to make precise optical measurements at a metal-dielectric interface. The basic idea behind these detectors is encapsulated in the coupling condition discussed above for the Kretschmann geometry: k|| = nkosin(&theta) = kspp. Since the surface plasmon is tightly bound to the metal-dielectric interface, any changes in that interface will translate directly into changes in the surface plasmon wave-vector kspp. This will cause a corresponding change in the optimal excitation angle for the Kretschmann coupler; by measuring this angle, the change in kspp can be deduced, allowing for the change in the refractive index to be computed. These detectors are sensitive enough that they can measure a change in film thickness of just a single monolayer, or refraction index changes (for example, due to chemical binding events on a bio-functionalized gold surface) as small as 10-6 RIU (refractive index units). For example, the commercial sensiQ detector from Nomadics is capable of measuring binding events of just one picogram of protein/mm2. More recently, there has been an explosion of interest in surface plasmons on nanoscale patterned surfaces. Using modern nanofabrication facilities, it is possible to make structures with feature sizes much smaller than the wavelength of visible light (&sim 500nm). For example, enhanced transmission through arrays of sub-wavelength slits has been experimentally demonstrated and has promising applications in photolithography and high-density optical data storage. Because surface plasmons can be launched at optical frequencies with much smaller wavelengths, it is possible to manipulate the flow of light on the scale of tens of nanometers. This has led to the coining of the term "plasmonics", where surface plasmons are used to manipulate an

ndex changes (for example, due to chemical binding events on a bio-functionalized gold surface) as small as 10-6 RIU (refractive index units). For example, the commercial sensiQ detector from Nomadics is capable of measuring binding events of just one picogram of protein/mm2. More recently, there has been an explosion of interest in surface plasmons on nanoscale patterned surfaces. Using modern nanofabrication facilities, it is possible to make structures with feature sizes much smaller than the wavelength of visible light (&sim 500nm). For example, enhanced transmission through arrays of sub-wavelength slits has been experimentally demonstrated and has promising applications in photolithography and high-density optical data storage. Because surface plasmons can be launched at optical frequencies with much smaller wavelengths, it is possible to manipulate the flow of light on the scale of tens of nanometers. This has led to the coining of the term "plasmonics", where surface plasmons are used to manipulate and transport information, analogous to electronics and photonics. Photonics has nearly unlimited bandwidth and almost no loss or dispersion, making it invaluable for high-throughput long-haul information networks. However, photonics components are diffraction-limited to micron-scale sizes, ruling out dense integration with nanoscale electronics. Plasmonics is potentially poised to bridge the tens of nanometer scale of modern electronics to the micron scale world of photonics. Many interesting devices, such as a 50nm metal-insulator-metal (MIM) surface plasmon waveguide capable of guiding 1.5um light even around 90o corners, have been proposed and are being actively investigated. Such devices have great promise, but also must overcome the limits imposed by the lossy propagation of surface plasmons in metals. The propagation lengths of surface plasmon waves in the visible and near infrared regimes are typically on the order of hundreds of microns on unpatterned surfaces, but drop to under thirty microns in sub-w

d transport information, analogous to electronics and photonics. Photonics has nearly unlimited bandwidth and almost no loss or dispersion, making it invaluable for high-throughput long-haul information networks. However, photonics components are diffraction-limited to micron-scale sizes, ruling out dense integration with nanoscale electronics. Plasmonics is potentially poised to bridge the tens of nanometer scale of modern electronics to the micron scale world of photonics. Many interesting devices, such as a 50nm metal-insulator-metal (MIM) surface plasmon waveguide capable of guiding 1.5um light even around 90o corners, have been proposed and are being actively investigated. Such devices have great promise, but also must overcome the limits imposed by the lossy propagation of surface plasmons in metals. The propagation lengths of surface plasmon waves in the visible and near infrared regimes are typically on the order of hundreds of microns on unpatterned surfaces, but drop to under thirty microns in sub-wavelength MIM waveguides. The propagation length in a modern optical fiber is drastically larger, on the order of kilometers. The small propagation lengths of surface plasmons are a significant hurdle in the practical implementation of plasmonics; however, researchers throughout the world are actively pursuing geometries which take account for this loss and new designs to limit the loss as much as possible. Surface plasmons have many exciting potential applications and rich underlying physics drawing heavily from solid-state physics and electrodynamics. Although known for over 50 years, there are still many unsolved theoretical and experimental problems in the field of surface plasmons. Additionally, with the use of modern nanofabrication techniques, a whole range of new plasmonic devices have become possible. Although not without their drawbacks, surface plasmon based devices have a plethora of laboratory and commercial applications--including the potential to revolutionize photonic-electronic integration wi

avelength MIM waveguides. The propagation length in a modern optical fiber is drastically larger, on the order of kilometers. The small propagation lengths of surface plasmons are a significant hurdle in the practical implementation of plasmonics; however, researchers throughout the world are actively pursuing geometries which take account for this loss and new designs to limit the loss as much as possible. Surface plasmons have many exciting potential applications and rich underlying physics drawing heavily from solid-state physics and electrodynamics. Although known for over 50 years, there are still many unsolved theoretical and experimental problems in the field of surface plasmons. Additionally, with the use of modern nanofabrication techniques, a whole range of new plasmonic devices have become possible. Although not without their drawbacks, surface plasmon based devices have a plethora of laboratory and commercial applications--including the potential to revolutionize photonic-electronic integration with the burgeouning field of plasmonics. Both bulk and surface plasmons have associated electromagnetic waves, and can consequently be described by Maxwell's equations. The coherent oscillations of electron motion can be encapsulated in the dielectric constant of the material. A simple model for the motion of an electron in a conductor is a free electron driven by the field of the electromagnetic wave. This electron motion can then be converted into a dielectric constant by using the definitions of the dipole moment, electric susceptibility, and dielectric constant: |Fig. A-1: Dispersion relation for bulk plasmons and free-space electromagnetic waves.| &omegap is known as the plasma frequency. This dielectric constant can then be inserted into the standard electromagnetic wave equation The wave equation allows for the standard propagating wave solution, given by This is a valid solution provided that This is the dispersion relation of bulk plasmon polaritons propagating in a metallic film. The dispersion relat

th the burgeouning field of plasmonics. Both bulk and surface plasmons have associated electromagnetic waves, and can consequently be described by Maxwell's equations. The coherent oscillations of electron motion can be encapsulated in the dielectric constant of the material. A simple model for the motion of an electron in a conductor is a free electron driven by the field of the electromagnetic wave. This electron motion can then be converted into a dielectric constant by using the definitions of the dipole moment, electric susceptibility, and dielectric constant: |Fig. A-1: Dispersion relation for bulk plasmons and free-space electromagnetic waves.| &omegap is known as the plasma frequency. This dielectric constant can then be inserted into the standard electromagnetic wave equation The wave equation allows for the standard propagating wave solution, given by This is a valid solution provided that This is the dispersion relation of bulk plasmon polaritons propagating in a metallic film. The dispersion relation gives the correspondence between the time-dependence of the electromagnetic wave (&omega), and the spatial variation (k); the wavelength of the wave is given by &lambda=2&pi/k. Figure A-1 shows a plot of the bulk plasmon dispersion relation (solid line), along with the free space dispersion relation (&omega = ck). For frequencies above the plasma frequency &omegap, the metal supports propagating modes. For frequencies below &omegap, k becomes imaginary and the fields exponentially decay inside the metal. For typical metals, h&omegap/2&pi &asymp 10eV (in the ultra-violet); for semiconductors, h&omegap/2&pi < 0.5eV (in the terahertz regime). Although bulk plasmons, which can exist even deep inside a metal, do not exist for &omega < &omegap, there is an additional solution to Maxwell's equations for these frequencies: surface plasmons. Surface plasmons are propagating waves bound to plasmon oscillations of electrons at a metal-dielectric interface. The field intensity of the wave is at a maximum at the inter

ion gives the correspondence between the time-dependence of the electromagnetic wave (&omega), and the spatial variation (k); the wavelength of the wave is given by &lambda=2&pi/k. Figure A-1 shows a plot of the bulk plasmon dispersion relation (solid line), along with the free space dispersion relation (&omega = ck). For frequencies above the plasma frequency &omegap, the metal supports propagating modes. For frequencies below &omegap, k becomes imaginary and the fields exponentially decay inside the metal. For typical metals, h&omegap/2&pi &asymp 10eV (in the ultra-violet); for semiconductors, h&omegap/2&pi < 0.5eV (in the terahertz regime). Although bulk plasmons, which can exist even deep inside a metal, do not exist for &omega < &omegap, there is an additional solution to Maxwell's equations for these frequencies: surface plasmons. Surface plasmons are propagating waves bound to plasmon oscillations of electrons at a metal-dielectric interface. The field intensity of the wave is at a maximum at the interface and exponentially decays away from the interface. The mathematical form of surface plasmons can be obtained by solving Maxwell's equations at a metal-dielectric interface: Assuming the metal-dielectric interface lies in the xy plane at z = 0, it can be shown that x-propagating surface waves of the following form are solutions to Maxwell's equations: with Ex,m = Ex,d (E|| continuous), &epsilonmEz,m = &epsilondEz,d (D&perp continuous), and Hy,m = Hy,d (B|| continuous); all other field components are zero. The subscript j is used to denote fields in the metal or dielectric. The dispersion relation for surface plasmons can be obtained by inserting the equations for E and H into Maxwell's equations and enforcing the boundary conditions: The dispersion relation, assuming &epsilonm = 1 - (&omegap/&omega)2, is shown in Fig. 1, along with the free-space and bulk plasmon dispersion relations. The surface plasmon dispersion relation always lies to the right of the free-space dispersion relations; as a result, free-

face and exponentially decays away from the interface. The mathematical form of surface plasmons can be obtained by solving Maxwell's equations at a metal-dielectric interface: Assuming the metal-dielectric interface lies in the xy plane at z = 0, it can be shown that x-propagating surface waves of the following form are solutions to Maxwell's equations: with Ex,m = Ex,d (E|| continuous), &epsilonmEz,m = &epsilondEz,d (D&perp continuous), and Hy,m = Hy,d (B|| continuous); all other field components are zero. The subscript j is used to denote fields in the metal or dielectric. The dispersion relation for surface plasmons can be obtained by inserting the equations for E and H into Maxwell's equations and enforcing the boundary conditions: The dispersion relation, assuming &epsilonm = 1 - (&omegap/&omega)2, is shown in Fig. 1, along with the free-space and bulk plasmon dispersion relations. The surface plasmon dispersion relation always lies to the right of the free-space dispersion relations; as a result, free-space radiation does not have enough momentum to launch surface plasmons. Additionally, the magnitude of kx for the surface plasmon asymptotically approaches &infin as &omega approaches &omegasp, where &epsilonm = -&epsilond. For &epsilonm = 1 - (&omegap/&omega)2, &omegasp = &omegap / &radic(1 + &epsilond). As kx increases, the surface plasmon wavelength decreases and &kappaz increases, resulting in a rapidly varying surface wave that is more tightly confined to the surface. For smaller values of &omega, the surface plasmon wave vector approaches the light line, the surface plasmon and free-space wavelengths become more similar, and the surface wave becomes less and less strongly confined to the surface. For the simple free-electron model considered thus far, there is no loss in the system and the surface wave will have an infinite propagation length. In real materials, however, there is loss and the wave will only propagate a finite length. The propagation length will decrease as the surface wave becomes mor

space radiation does not have enough momentum to launch surface plasmons. Additionally, the magnitude of kx for the surface plasmon asymptotically approaches &infin as &omega approaches &omegasp, where &epsilonm = -&epsilond. For &epsilonm = 1 - (&omegap/&omega)2, &omegasp = &omegap / &radic(1 + &epsilond). As kx increases, the surface plasmon wavelength decreases and &kappaz increases, resulting in a rapidly varying surface wave that is more tightly confined to the surface. For smaller values of &omega, the surface plasmon wave vector approaches the light line, the surface plasmon and free-space wavelengths become more similar, and the surface wave becomes less and less strongly confined to the surface. For the simple free-electron model considered thus far, there is no loss in the system and the surface wave will have an infinite propagation length. In real materials, however, there is loss and the wave will only propagate a finite length. The propagation length will decrease as the surface wave becomes more tightly bound to the interface (as &omega approaches &omegasp), as the energy of the field becomes more concentrated in the metal. Consequently, there is a trade-off between confinement and propagation distance. A final property of interest that can be obtained from the dispersion diagram shown in figure A-2 is the group velocity of the surface wave. Any information carried by the wave will propagate at the wave group velocity, vg = (&part &omega / &part k). As &omega approaches &omegasp, vg asymptotically approaches zero. The dispersion diagram plots shown above were generated using matplotlib, an open source plotting library written in Python; the source code of the python script for the plots can be downloaded here. The images of the above equations were generated using latex and latex2html; the .tex file can be downloaded here. The figure of the Kretschmann-Raether coupler was drawn in Inkscape, an open source vector graphics editor; the svg file can be downloaded here. © 2007 Justin White. The author g

e tightly bound to the interface (as &omega approaches &omegasp), as the energy of the field becomes more concentrated in the metal. Consequently, there is a trade-off between confinement and propagation distance. A final property of interest that can be obtained from the dispersion diagram shown in figure A-2 is the group velocity of the surface wave. Any information carried by the wave will propagate at the wave group velocity, vg = (&part &omega / &part k). As &omega approaches &omegasp, vg asymptotically approaches zero. The dispersion diagram plots shown above were generated using matplotlib, an open source plotting library written in Python; the source code of the python script for the plots can be downloaded here. The images of the above equations were generated using latex and latex2html; the .tex file can be downloaded here. The figure of the Kretschmann-Raether coupler was drawn in Inkscape, an open source vector graphics editor; the svg file can be downloaded here. © 2007 Justin White. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author. R. H. Ritchie, Phys. Rev. 106, 874 (1957). C. J. Powell and J. B. Swan, Phys. Rev. 115, 869 (1959). C. J. Powell and J. B. Swan, Phys. Rev. 116, 81 (1959). C. Kittel, Introduction to Solid State Physics, 7th ed. (Wiley, 1995). E. Kretschmann, Z. Phys. 241, 313 (1971), H. Raether, Surface Plasmons on Smooth and Rough Surfaces and on Gratings (Springer, 1988), pp 1-133. http://www.nomadics.com T.W. Ebessen et. al, Nature 391, 667 (1998). S.A. Maier et. al, Adv. Mat. 13, 1501 (2001). G. Veronis and S. Fan, Appl. Phys. Lett. 87, 131102 (2005). J. D. Jackson, Classical Electrodynamics, 3rd ed. (Wiley, 1998).

rants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author. R. H. Ritchie, Phys. Rev. 106, 874 (1957). C. J. Powell and J. B. Swan, Phys. Rev. 115, 869 (1959). C. J. Powell and J. B. Swan, Phys. Rev. 116, 81 (1959). C. Kittel, Introduction to Solid State Physics, 7th ed. (Wiley, 1995). E. Kretschmann, Z. Phys. 241, 313 (1971), H. Raether, Surface Plasmons on Smooth and Rough Surfaces and on Gratings (Springer, 1988), pp 1-133. http://www.nomadics.com T.W. Ebessen et. al, Nature 391, 667 (1998). S.A. Maier et. al, Adv. Mat. 13, 1501 (2001). G. Veronis and S. Fan, Appl. Phys. Lett. 87, 131102 (2005). J. D. Jackson, Classical Electrodynamics, 3rd ed. (Wiley, 1998).

The Life and Martyrdom of Polycarp (Born about 70 A.D. - Martyred about 168 A.D.) Pastor David L. Brown, Ph.D. I have an old book in my study that says on its spine "Wake's Epistles." It was printed in 1710. This book contains some of the history and letters of the post-Apostolic preachers and accounts to their suffering and martyrdom. On page 52 there is a chapter on the martyrdom of Polycarp, pastor of the Church of Smyrna. Briefly, let me share with you the story of his life and his death. Polycarp was born abound 70 A.D. He was sold as a slave in his childhood to a wealthy woman named Calisto. She reared him as her son. He came to know Christ as his Savior in those early years. As he grew older, he had the opportunity to study under the Apostle John and others who had personally sat under the teaching of Jesus Christ. Polycarp was actively involved in serving the Lord in the Church of Smyrna. Upon the death of Calisto, he became heir to all of her estate. He used his inheritance to advance the cause of Christ and to help those who were in need. When the of his church, Pastor Bucolos, died the Apostles and particularly the Apostle John appointed Polycarp to be the Pastor of the Church of Smyrna. Polycarp faithfully ministered in that church for many years. Persecution of Christians was the order of the day when Marcus Aurelius was the Emporer of Rome (161-180). For many years Polycarp was spared. But, the full forced of persecution was unleashed on Polycarp in the later years of his ministry. Three days before he was arrested the Lord revealed to him in a dream that he would be burned at the stake. When the soldiers came to get him, his friends insisted on hiding him. Polycarp made it clear that in the future, he would not all himself to be hidden. Soon the soldiers discovered where he had been taken. When he saw them coming, he went out and greeted them warmly and offered them food. As they were eating, he requested that he be allowed to pray before they took him away. His request was granted. For two hours h

rist and to help those who were in need. When the of his church, Pastor Bucolos, died the Apostles and particularly the Apostle John appointed Polycarp to be the Pastor of the Church of Smyrna. Polycarp faithfully ministered in that church for many years. Persecution of Christians was the order of the day when Marcus Aurelius was the Emporer of Rome (161-180). For many years Polycarp was spared. But, the full forced of persecution was unleashed on Polycarp in the later years of his ministry. Three days before he was arrested the Lord revealed to him in a dream that he would be burned at the stake. When the soldiers came to get him, his friends insisted on hiding him. Polycarp made it clear that in the future, he would not all himself to be hidden. Soon the soldiers discovered where he had been taken. When he saw them coming, he went out and greeted them warmly and offered them food. As they were eating, he requested that he be allowed to pray before they took him away. His request was granted. For two hours he prayed fervently out loud and my book says, "inasmuch that many of the soldiers began to repent, that they were come out against so godly an old man." When he was done praying they set him on a donkey and took him into the city to be tried as one who was an adversary of the authorized pagan religion. When he arrived, they sat him in a chariot and began to urge him to say the Caesar was God and offer a sacrifice to him. They said, there is no harm in that is there? At first he refused to answer. Finally, after they continued to press him Polycarp said, "I shall not do what you would persuade me to." This made his judges very angry. They had confidently supposed that they would be able to easily persuade him to do what they wanted him to do. They became vicious in their words and actions. They literally threw him out of the chariot he had been sitting in, which cause serious injury to his thigh. This display of force incited the blood thirsty mob to the point that they were so loud in their curses and jeers t

e prayed fervently out loud and my book says, "inasmuch that many of the soldiers began to repent, that they were come out against so godly an old man." When he was done praying they set him on a donkey and took him into the city to be tried as one who was an adversary of the authorized pagan religion. When he arrived, they sat him in a chariot and began to urge him to say the Caesar was God and offer a sacrifice to him. They said, there is no harm in that is there? At first he refused to answer. Finally, after they continued to press him Polycarp said, "I shall not do what you would persuade me to." This made his judges very angry. They had confidently supposed that they would be able to easily persuade him to do what they wanted him to do. They became vicious in their words and actions. They literally threw him out of the chariot he had been sitting in, which cause serious injury to his thigh. This display of force incited the blood thirsty mob to the point that they were so loud in their curses and jeers that no one could hear. As they were dragging Polycarp to the place of execution, a voice rang out from Heaven loud and clear, above the harangue of the crowd which said, "Be strong, Polycarp, and quit thyself like a man." [The phrase "quit you" means, to carry through, or perform to the end. Hence, be strong and stand like a man to the end.] The record states that while no one saw who it was that spoke to Polycarp, many of the believers who were in the crowd clearly heard the voice also. To be sure, Polycarp stood for the Lord Jesus Christ to the end, despite all the efforts to persuade him to renounce Christ. One of the judges tried to get him to deny his faith by saying, "Reverence thy old age Swear by Casear's Fortune. Repent, and say; Take away the Wicked." The historian goes on to say, "Polycarp, looking with a stern countenance upon the whole multitude of wicked Gentiles, that was gathered together in the Lifts, and shaking his hand at them, looked up to Heaven, and groaning said, Take away the Wicked."

hat no one could hear. As they were dragging Polycarp to the place of execution, a voice rang out from Heaven loud and clear, above the harangue of the crowd which said, "Be strong, Polycarp, and quit thyself like a man." [The phrase "quit you" means, to carry through, or perform to the end. Hence, be strong and stand like a man to the end.] The record states that while no one saw who it was that spoke to Polycarp, many of the believers who were in the crowd clearly heard the voice also. To be sure, Polycarp stood for the Lord Jesus Christ to the end, despite all the efforts to persuade him to renounce Christ. One of the judges tried to get him to deny his faith by saying, "Reverence thy old age Swear by Casear's Fortune. Repent, and say; Take away the Wicked." The historian goes on to say, "Polycarp, looking with a stern countenance upon the whole multitude of wicked Gentiles, that was gathered together in the Lifts, and shaking his hand at them, looked up to Heaven, and groaning said, Take away the Wicked." But the judge was not satisfied with this. He said, "Sware, and I will set thee at liberty; reproach Christ." It is at this point that Polycarp gives his famous response -- "Eighty and six years have I now served Christ, and he has never done me the least wrong: How then can I blaspheme my King and my Savior?" The judge then angrily urges him to, "swear by the Genius of Caesar." Polycarp refuses, but offered to share his faith in Christ. The judge rejected the offer and threatened, "I have wild beasts ready, to those I will cast thee except thou repent." Polycarp responds calmly, "Call for them then: For we Christians are fixed in our minds not to change from good to evil; But for me it will be good to be changed from Evil, to Good." The furious judge said, "Seeing that thou dispiseth the Wild Beasts, I will cause thee to be devoured by Fire, unless thou shall repent." Polycarp answered, "Thou threatenest me with Fire which burns for an hour, and so is extinguished; but knowest not the Fire of the Future Jud

But the judge was not satisfied with this. He said, "Sware, and I will set thee at liberty; reproach Christ." It is at this point that Polycarp gives his famous response -- "Eighty and six years have I now served Christ, and he has never done me the least wrong: How then can I blaspheme my King and my Savior?" The judge then angrily urges him to, "swear by the Genius of Caesar." Polycarp refuses, but offered to share his faith in Christ. The judge rejected the offer and threatened, "I have wild beasts ready, to those I will cast thee except thou repent." Polycarp responds calmly, "Call for them then: For we Christians are fixed in our minds not to change from good to evil; But for me it will be good to be changed from Evil, to Good." The furious judge said, "Seeing that thou dispiseth the Wild Beasts, I will cause thee to be devoured by Fire, unless thou shall repent." Polycarp answered, "Thou threatenest me with Fire which burns for an hour, and so is extinguished; but knowest not the Fire of the Future Judgment, and of that Eternal Punishment, which is reserved for the Ungodly. But why tarriest thou? Bring forth what thou wilt!" The judge loudly cried out three times, "Polycarp has confessed himself to be a Christian." The mob responded in fury, "This is the Doctor of Asia; The Father of the Christians; an the overthrower of our Gods. He that has taught so many not to sacrifice, nor pay any worship to the Gods." At first they cried out that the lions should be loosed on him and then that he should be burned alive. They took Polycarp to the stake and were going to nail him there. He spoke up and said, "Let me alone as I am: For he who has given me strength to endure the Fire, will also enable me, without your securing me by nails, to stand without moving in the pile." The merely tied him to the stake. He prayed this prayer before the fire was was kindled -- Lord God Almighty, the Father of thy Well-beloved, and Blessed Son, Jesus Christ, by whom we have received Knowledge of thee; the God of Angels and Powers,

gment, and of that Eternal Punishment, which is reserved for the Ungodly. But why tarriest thou? Bring forth what thou wilt!" The judge loudly cried out three times, "Polycarp has confessed himself to be a Christian." The mob responded in fury, "This is the Doctor of Asia; The Father of the Christians; an the overthrower of our Gods. He that has taught so many not to sacrifice, nor pay any worship to the Gods." At first they cried out that the lions should be loosed on him and then that he should be burned alive. They took Polycarp to the stake and were going to nail him there. He spoke up and said, "Let me alone as I am: For he who has given me strength to endure the Fire, will also enable me, without your securing me by nails, to stand without moving in the pile." The merely tied him to the stake. He prayed this prayer before the fire was was kindled -- Lord God Almighty, the Father of thy Well-beloved, and Blessed Son, Jesus Christ, by whom we have received Knowledge of thee; the God of Angels and Powers, and of every Creature, and especially the whole Race of Just Men who live in thy presence! I give thee hearty thanks that thou hast vouchsafed (allowed) to bring me to this Day, and to this Hour; that I should have a part in the Number of thy Martyrs, in the Cup of thy Christ, to the Resurrection of Eternal Life, both of Soul and Body, in the Incorruption of the Holy Ghost. Among which may I be accepted this Day before thee, as a fat and acceptable Sacrifice; as thou the true God, with who is no falsehood, has both before ordained, and manifested unto me, and also hath now fulfilled it. For this, and for all things else, I praise thee, I bless thee, I glorify thee by the Eternal, and Heavenly High Priest, Jesus Christ they Beloved Son; whit whom to Thee and the Holy Ghost, be Glory both now, and to all succeeding Ages, AMEN. Upon the "AMEN" the executioner lighted the fire, but something strange happened. The flames arched around Polycarp like a sail of a ship filled with wind and he would not burn. After som

and of every Creature, and especially the whole Race of Just Men who live in thy presence! I give thee hearty thanks that thou hast vouchsafed (allowed) to bring me to this Day, and to this Hour; that I should have a part in the Number of thy Martyrs, in the Cup of thy Christ, to the Resurrection of Eternal Life, both of Soul and Body, in the Incorruption of the Holy Ghost. Among which may I be accepted this Day before thee, as a fat and acceptable Sacrifice; as thou the true God, with who is no falsehood, has both before ordained, and manifested unto me, and also hath now fulfilled it. For this, and for all things else, I praise thee, I bless thee, I glorify thee by the Eternal, and Heavenly High Priest, Jesus Christ they Beloved Son; whit whom to Thee and the Holy Ghost, be Glory both now, and to all succeeding Ages, AMEN. Upon the "AMEN" the executioner lighted the fire, but something strange happened. The flames arched around Polycarp like a sail of a ship filled with wind and he would not burn. After some time, the command was given to the executioner to stab him with a sword, so he did. The result was that so much blood flowed from the wound that it extinguished the fire. The fire was rekindled and Polycarps body was burned to ashes. Polycarp was faithful to the Lord unto death. And it is interesting to note that the congregation of the Church of Smyrna believed that the Apostle John, under the inspiration of the Holy Spirit, penned Revelation 2:8-10 with their pastor, Polycarp, prophetically in mind. Revelation 2:8-10 says, And unto the angel of the church in Smyrna write; These things saith the first and the last, which was dead, and is alive; 9 I know thy works, and tribulation , and poverty, (but thou art rich) and I know the blasphemy of them which say they are Jews, and are not, but are the synagogue of Satan. 10 Fear none of those things which thou shalt suffer: behold, the devil shall cast some of you into prison, that ye may be tried; and ye shall have tribulation ten days: be thou faithful unto de

e time, the command was given to the executioner to stab him with a sword, so he did. The result was that so much blood flowed from the wound that it extinguished the fire. The fire was rekindled and Polycarps body was burned to ashes. Polycarp was faithful to the Lord unto death. And it is interesting to note that the congregation of the Church of Smyrna believed that the Apostle John, under the inspiration of the Holy Spirit, penned Revelation 2:8-10 with their pastor, Polycarp, prophetically in mind. Revelation 2:8-10 says, And unto the angel of the church in Smyrna write; These things saith the first and the last, which was dead, and is alive; 9 I know thy works, and tribulation , and poverty, (but thou art rich) and I know the blasphemy of them which say they are Jews, and are not, but are the synagogue of Satan. 10 Fear none of those things which thou shalt suffer: behold, the devil shall cast some of you into prison, that ye may be tried; and ye shall have tribulation ten days: be thou faithful unto death, and I will give thee a crown of life. John wrote Revelation in about 96 A.D. and Polycarp was martyred in about 168 A.D. [Note: The Graphic of Polycarp is from Holy Transfiguration Monastery]

ath, and I will give thee a crown of life. John wrote Revelation in about 96 A.D. and Polycarp was martyred in about 168 A.D. [Note: The Graphic of Polycarp is from Holy Transfiguration Monastery]

|Up a level| This activity gives students the chance to talk about the Summer School (also The ALE), to get them talking to fellow students after the experience of Jena/ ALE. This could be used online or face2face. This activity links with the Summer School and gives students another opportunity to develop confidence before the oral. These cue cards for use either online or face2face to enable students to share tips on surviving exams. Tutorial material collection covering work, talking about the past and tourism. Materials collection covering the topic Glueck, Wege, Philosophie and Ethik. Materials collection covering definitions of Kunst and describing comics and cartoons. Materials collection to discuss topics of praktische Philosophie and Ethik. A collection of activities centred around the topic of "Wohnen" and preparation of TMA1 In this first tutorial students get to know each other and learn about some basic functionalities of their online tutorial environment (Elluminate). This activity uses the same introductory whiteboard slides as L203Unit1Act1a (to familiarize students with Elluminate) but additionally includes some PowerPoints to trigger conversations about German-speaking countries. It is aimed at groups who have already met face-to-face and don't need another tutorial introducing themselves. For this activity students will need to do some preparatory work online using web addresses of German accommodation agencies to find a house, flat or room they like. They will then describe their chosen object in the tutorial and talk about their preferences. In this activity students discuss how they go about finding information, and talk about the benefits and disadvantages of a collaborative online encyclopedia like wikipedia. In this activity students write about their dreams for the future and then check each others writing by using a checklist. In this activity students talk about their working lives and discuss their views. They describe what their dream job might be like. Students talk about working co

introductory whiteboard slides as L203Unit1Act1a (to familiarize students with Elluminate) but additionally includes some PowerPoints to trigger conversations about German-speaking countries. It is aimed at groups who have already met face-to-face and don't need another tutorial introducing themselves. For this activity students will need to do some preparatory work online using web addresses of German accommodation agencies to find a house, flat or room they like. They will then describe their chosen object in the tutorial and talk about their preferences. In this activity students discuss how they go about finding information, and talk about the benefits and disadvantages of a collaborative online encyclopedia like wikipedia. In this activity students write about their dreams for the future and then check each others writing by using a checklist. In this activity students talk about their working lives and discuss their views. They describe what their dream job might be like. Students talk about working conditions in different work environments. They exchange ideas and suggestions using conditional clauses and modal verbs. In this activity students discuss ideas for an internet start-up company and then present their suggestion. In this activity students discuss cultural differences between German-speaking countries and the UK. In this activity students discuss newspapers, in particular the tabloid press. In groups, they then write some tabloid-style articles. In this activity students collect arguments and have a debate on whether or not soap operas are a waste of time. In this activity students make plans for a new radio station. They use expressions of opinion and reported speech. In this activity students discuss the influence of different mass media on their audiences. In groups, they prepare and deliver a presentation on the topic. In this activity students discuss how they think the internet might change in the future. They make suggestions for desirable developments and react to the suggestions of othe

nditions in different work environments. They exchange ideas and suggestions using conditional clauses and modal verbs. In this activity students discuss ideas for an internet start-up company and then present their suggestion. In this activity students discuss cultural differences between German-speaking countries and the UK. In this activity students discuss newspapers, in particular the tabloid press. In groups, they then write some tabloid-style articles. In this activity students collect arguments and have a debate on whether or not soap operas are a waste of time. In this activity students make plans for a new radio station. They use expressions of opinion and reported speech. In this activity students discuss the influence of different mass media on their audiences. In groups, they prepare and deliver a presentation on the topic. In this activity students discuss how they think the internet might change in the future. They make suggestions for desirable developments and react to the suggestions of others. In this activity students discuss what art means to them. Students debate whether the internet is the death toll for books. Before this tutorial students should have read the story "Das Judenauto" by Franz Fühmann. They will discuss the story and find out more about its author. In this activity students talk about their own and other people's definition of "Glück". Students discuss pilgrimages and join a web tour of a traditional walk. They then devise their own route. After some preparatory steps students engage in a debate about the commercialisation of religious festivals or other traditional celebrations. Students talk about aspects of GDR history and plan a visit to the Gedenkstätte in Hohenschönhausen. A group&pair work activity in which students exchange info and look for a suitable member for their WG. Many thanks to Dr Beatriz de los Arcos - whose original idea I have adapted to produce this resource. Beatriz' resource can be found here: http://loro.open.ac.uk/969

rs. In this activity students discuss what art means to them. Students debate whether the internet is the death toll for books. Before this tutorial students should have read the story "Das Judenauto" by Franz Fühmann. They will discuss the story and find out more about its author. In this activity students talk about their own and other people's definition of "Glück". Students discuss pilgrimages and join a web tour of a traditional walk. They then devise their own route. After some preparatory steps students engage in a debate about the commercialisation of religious festivals or other traditional celebrations. Students talk about aspects of GDR history and plan a visit to the Gedenkstätte in Hohenschönhausen. A group&pair work activity in which students exchange info and look for a suitable member for their WG. Many thanks to Dr Beatriz de los Arcos - whose original idea I have adapted to produce this resource. Beatriz' resource can be found here: http://loro.open.ac.uk/969

One of my favorite books, How Many Seeds in a Pumpkin?, is perfect for this time of year. Children estimate how many pumpkin seeds are in pumpkins of varying sizes. In order to find the number of seeds, children count by 2s, 5s, and 10s, and learn that the smallest pumpkin actually has the most. Maybe you'll want to read it and do some of the "Pumpkin Problem Solving" or "Fall Math Activities" over at Mathwire...one of my FAVORITE math idea sites! ;)

Recently, I have been (re)reading Fitelson and Hawthorne's extensive and thorough discussion of "The Wason task(s) and the paradox of confirmation", which revived a puzzling little thought that I have. Wason's selection task is widely known, I guess. You have four cards as follows: Each card has a letter on one side and a number on the other. A hypothesis is at issue, i.e., H = "for any card, if there's a vowel on one side, then there's an even number on the other side". Your task is to say which of the cards you need to turn over in order to find out whether H is true or false. (I want to be very careful here with the wording - I'm closely following Johnson-Laird & Wason, 1977, via Humberstone, 1994). [Edit: By the way - I forgot to say! - people strongly tend to choose the E- and the 4-card. The point is if this makes logical sense.] Two cases have to be clearly distinguished: either (i) the domain of H is restricted to the four cards initially presented, or (ii) a larger deck is involved, from which those four cards have been sampled. If (ii) is allowed for, then very interesting issues arise (most famously tackled by Oaksford and Chater, 1994). However, Wason had (i) in mind, and everyone seems to agree that in that case the correct answer is: turn over the E- and the 7-card. Why? From Wason on, the standard answer has been more or less the same: because only by turning the E- and the 7-card you could possibly falsify H. (Wason's experimental idea was apparently inspired by his knowledge of Popper.) But the logical point seems stronger than that: if the domain is restricted, then H is logically equivalent to "there's an even number behind E and a consonant behind 7". Logically equivalent - period. Not just such that it would otherwise be falsified. The proof is easy, and it provides ultimate motivation for why the selection of E and 7 is indeed compelling (recall how the question is spelled out: which cards are needed to find out whether H is true or false). Yet I have consistently found variants of the "Popp

four cards have been sampled. If (ii) is allowed for, then very interesting issues arise (most famously tackled by Oaksford and Chater, 1994). However, Wason had (i) in mind, and everyone seems to agree that in that case the correct answer is: turn over the E- and the 7-card. Why? From Wason on, the standard answer has been more or less the same: because only by turning the E- and the 7-card you could possibly falsify H. (Wason's experimental idea was apparently inspired by his knowledge of Popper.) But the logical point seems stronger than that: if the domain is restricted, then H is logically equivalent to "there's an even number behind E and a consonant behind 7". Logically equivalent - period. Not just such that it would otherwise be falsified. The proof is easy, and it provides ultimate motivation for why the selection of E and 7 is indeed compelling (recall how the question is spelled out: which cards are needed to find out whether H is true or false). Yet I have consistently found variants of the "Popperian" argument, and never seen an overt statement of that plain logical equivalence. I'd be happy to know if anyone alse ever has. Humberstone, L. (1994), "Hempel meets Wason", Erkenntnis, 41 (1994), pp. 391–402. Johnson-Laird, P.N. & Wason, P.C. (1977), "A theoretical analysis of insight into a reasoning task", in P.N. Johnson-Laird & P.C. Wason (eds.), Thinking: Readings in Cognitive Science, Cambridge University Press, Cambridge, pp. 143-157. Oaksford, M. & Chater N. (1994), "A rational analysis of the selection task as optimal data selection", Psychological Review, 101 (1994), pp. 608–631.

erian" argument, and never seen an overt statement of that plain logical equivalence. I'd be happy to know if anyone alse ever has. Humberstone, L. (1994), "Hempel meets Wason", Erkenntnis, 41 (1994), pp. 391–402. Johnson-Laird, P.N. & Wason, P.C. (1977), "A theoretical analysis of insight into a reasoning task", in P.N. Johnson-Laird & P.C. Wason (eds.), Thinking: Readings in Cognitive Science, Cambridge University Press, Cambridge, pp. 143-157. Oaksford, M. & Chater N. (1994), "A rational analysis of the selection task as optimal data selection", Psychological Review, 101 (1994), pp. 608–631.

Euler Line Proof Date: 11/13/2001 at 23:58:00 From: Natalie Loser Subject: Euler line Prove that if the Euler line of a triangle passes through a vertex, then the triangle is either right or isosceles. Date: 11/14/2001 at 03:05:52 From: Doctor Floor Subject: Re: Euler line Hi, Natalie, Thanks for writing. If (for instance) vertex A lies on the Euler line, then the Euler line of ABC is the line through A and the centroid G = the median through A. So the midpoint of BC is on the line as well. Now if the orthocenter H lies on the median through A, this means that either: - A is not equal to H. Then the median through A is also the altitude from A, and thus ABC is an isosceles triangle with A as top. - A is equal to H. Then A is a right angle, because AB must be the altitude from B to AC, and AC must be the altitude from C to AB. This proves your statement. If you need more help, just write back. Best regards, - Doctor Floor, The Math Forum http://mathforum.org/dr.math/ Search the Dr. Math Library: Ask Dr. MathTM © 1994-2015 The Math Forum

As space exploration geared up in the 1960s, scientists were faced with a new dilemma. How could they recognize life on other planets, where it may have evolved very differently—and therefore have a different chemical signature—than it has on Earth? James Lovelock, father of the Gaia theory, gave this advice: Look for order. Every organism is a brief upwelling of structure from chaos, a self-assembled wonder that must jealously defend its order until the day it dies. Sophisticated information processing is necessary to preserve and pass down the rules for maintaining this order, yet life is built out of the messiest materials: tumbling chemicals, soft cells, and tangled polymers. Shouldn’t, therefore, information in biological systems be handled messily, and wasted? In fact, many biological computations are so perfect that they bump up against the mathematical limits of efficiency; genius is our inheritance. DNA stores information at a density per unit volume exceeding any other known medium, from hard disks to quantum holography.1 It’s so dense that all the world’s digital data could be stored in a dot of DNA the weight of eight paper clips. This remarkable storage density is paired with an equally remarkable reading mechanism. A developing embryo must self-direct the rapid division, migration, and specialization of its constituent cells based on the information stored in DNA. Cells diverge from one another to grow in different ways, depending on their position in the embryo. This means that precise control of gene expression is necessary both in space and in time. Even minor errors could spell death or deformity for the organism. The question is, how quickly and effectively can spatial information be communicated in order for development to unfold properly? Alan Turing, the father of modern computing, was fascinated by the idea that life might be reducible to mathematical laws, and tackled this question in the early 1950s. He predicted that the spatial patterning of tissues during embryonic development could be

to quantum holography.1 It’s so dense that all the world’s digital data could be stored in a dot of DNA the weight of eight paper clips. This remarkable storage density is paired with an equally remarkable reading mechanism. A developing embryo must self-direct the rapid division, migration, and specialization of its constituent cells based on the information stored in DNA. Cells diverge from one another to grow in different ways, depending on their position in the embryo. This means that precise control of gene expression is necessary both in space and in time. Even minor errors could spell death or deformity for the organism. The question is, how quickly and effectively can spatial information be communicated in order for development to unfold properly? Alan Turing, the father of modern computing, was fascinated by the idea that life might be reducible to mathematical laws, and tackled this question in the early 1950s. He predicted that the spatial patterning of tissues during embryonic development could be controlled through the concentration of chemical signalers, called morphogens. He derived equations showing that interactions between morphogens that activate and inhibit one another’s gene expression could set up standing waves of morphogen concentration, and control embryonic patterning. With just four variables—production and degradation rates, diffusion rate, and interaction strength—Turing could reproduce biologically plausible, self-directed pattern formation. His prediction of a chemical system of information management was proven true decades later with the first discovery of a morphogen in fruit flies, called bicoid (though his equations proved to be too simple). Cells in a fruit fly embryo with high bicoid concentration become the fly’s head, and those with lower concentration become its body. What is remarkable, however, is how quickly and accurately these cells differentiate. In 2007, a team led by Princeton biophysicist Thomas Gregor measured the concentration gradient and diffusion rate of bico

controlled through the concentration of chemical signalers, called morphogens. He derived equations showing that interactions between morphogens that activate and inhibit one another’s gene expression could set up standing waves of morphogen concentration, and control embryonic patterning. With just four variables—production and degradation rates, diffusion rate, and interaction strength—Turing could reproduce biologically plausible, self-directed pattern formation. His prediction of a chemical system of information management was proven true decades later with the first discovery of a morphogen in fruit flies, called bicoid (though his equations proved to be too simple). Cells in a fruit fly embryo with high bicoid concentration become the fly’s head, and those with lower concentration become its body. What is remarkable, however, is how quickly and accurately these cells differentiate. In 2007, a team led by Princeton biophysicist Thomas Gregor measured the concentration gradient and diffusion rate of bicoid in fruit fly embryos. They estimated that it would take around two hours for embryonic cells to measure the morphogen concentration with enough precision for adjacent cells to mature differently (measurement precision increases with measurement time). But this is nearly the entirety of the fruit fly’s developmental period, from fertilization to cellularization. The embryo was developing faster and more precisely than should have been possible. Gregor proposed that multiple cells could be sharing information with each other using a second signaling chemical: One candidate is a morphogen called hunchback. This would allow them to compute a spatial average of bicoid concentrations, rather than relying entirely on individual readings. The averaging process would be less susceptible to variation and noise, and would allow the required pattern accuracy to be achieved in about three minutes, rather than two hours. The process is not just ingenious, but efficient. To find out how efficient, physicist William Biale

id in fruit fly embryos. They estimated that it would take around two hours for embryonic cells to measure the morphogen concentration with enough precision for adjacent cells to mature differently (measurement precision increases with measurement time). But this is nearly the entirety of the fruit fly’s developmental period, from fertilization to cellularization. The embryo was developing faster and more precisely than should have been possible. Gregor proposed that multiple cells could be sharing information with each other using a second signaling chemical: One candidate is a morphogen called hunchback. This would allow them to compute a spatial average of bicoid concentrations, rather than relying entirely on individual readings. The averaging process would be less susceptible to variation and noise, and would allow the required pattern accuracy to be achieved in about three minutes, rather than two hours. The process is not just ingenious, but efficient. To find out how efficient, physicist William Bialek used nucleus-by-nucleus measurements of morphogens in fruit-fly embryos to study how closely hunchback concentrations followed changes in bicoid concentrations. He found that the fidelity of this information transfer was 90 percent of the theoretical maximum. A video interview with the author, Kelly Clancy. When an embryo develops into an adult, it confronts a new information processing challenge. Its body must learn how to sample and integrate both external and internal information. Odorant molecules signal a predator, prompting a rodent to flee. The setting sun triggers melatonin release, causing a cascade of effects throughout the body, inducing sleep. Internal chemoreceptors measure high carbon dioxide levels, causing an athlete to breathe faster. Information from microscopic measurements, sampled by disparate sensors, must be integrated and used to make macroscopic decisions that are efficiently communicated back out to relevant body parts. Here, too, nature has discovered an optimal solution, whose de

k used nucleus-by-nucleus measurements of morphogens in fruit-fly embryos to study how closely hunchback concentrations followed changes in bicoid concentrations. He found that the fidelity of this information transfer was 90 percent of the theoretical maximum. A video interview with the author, Kelly Clancy. When an embryo develops into an adult, it confronts a new information processing challenge. Its body must learn how to sample and integrate both external and internal information. Odorant molecules signal a predator, prompting a rodent to flee. The setting sun triggers melatonin release, causing a cascade of effects throughout the body, inducing sleep. Internal chemoreceptors measure high carbon dioxide levels, causing an athlete to breathe faster. Information from microscopic measurements, sampled by disparate sensors, must be integrated and used to make macroscopic decisions that are efficiently communicated back out to relevant body parts. Here, too, nature has discovered an optimal solution, whose details can be read in the shapes of our anatomical structures. One of the earliest observations of a mathematical relation in biology was that almost every living creature in every ecosystem on the planet, spanning more than 20 orders of magnitude in size from uni- to multi-cellular, has features that scale with the mass of the organism, including heart rate, life span, aorta size, tree trunk size, and metabolic rate. This is called allometric scaling. A rule of thumb common in the halls of Intel was programmed into our bodies eons ago. Strangely, the relationship between these features and an organism’s mass usually follows a power law. That means, for example, that metabolic rate depends on the organism’s mass, raised to some constant power. Even stranger, the constant for the majority of these features is some multiple of one fourth. Physicist Geoffrey West has argued that this scaling results from the ubiquity of fractal-like networks within organisms. Fractals are structures that have similar structure at

tails can be read in the shapes of our anatomical structures. One of the earliest observations of a mathematical relation in biology was that almost every living creature in every ecosystem on the planet, spanning more than 20 orders of magnitude in size from uni- to multi-cellular, has features that scale with the mass of the organism, including heart rate, life span, aorta size, tree trunk size, and metabolic rate. This is called allometric scaling. A rule of thumb common in the halls of Intel was programmed into our bodies eons ago. Strangely, the relationship between these features and an organism’s mass usually follows a power law. That means, for example, that metabolic rate depends on the organism’s mass, raised to some constant power. Even stranger, the constant for the majority of these features is some multiple of one fourth. Physicist Geoffrey West has argued that this scaling results from the ubiquity of fractal-like networks within organisms. Fractals are structures that have similar structure at very different spatial scales—one familiar example is the vasculature of a leaf, whose branching geometry is replicated in miniature across the leaf’s surface. They can be found in a dizzying variety of systems, including our nervous system, blood vessels, capillaries in plant leaves, lung bronchioles, the calyxes of kidneys, neurons, root systems, and mitochondrial cristae. Why would nature use fractal geometry so regularly? Mathematically, fractals are interpreted as having a fractional dimension higher than the space they reside in: A fractal drawn on a two-dimensional sheet of paper, for example, has a higher dimension—say, 2.1. This is a useful feature, allowing nature to pack some part of a fourth dimension into three-dimensional space. To see why it might be useful, we can turn to a well-known result in the semiconductor industry, called Pollack’s Rule. It states that the speedup achievable by adding computing elements to a processor is proportional to the number of added elements, raised to the power

very different spatial scales—one familiar example is the vasculature of a leaf, whose branching geometry is replicated in miniature across the leaf’s surface. They can be found in a dizzying variety of systems, including our nervous system, blood vessels, capillaries in plant leaves, lung bronchioles, the calyxes of kidneys, neurons, root systems, and mitochondrial cristae. Why would nature use fractal geometry so regularly? Mathematically, fractals are interpreted as having a fractional dimension higher than the space they reside in: A fractal drawn on a two-dimensional sheet of paper, for example, has a higher dimension—say, 2.1. This is a useful feature, allowing nature to pack some part of a fourth dimension into three-dimensional space. To see why it might be useful, we can turn to a well-known result in the semiconductor industry, called Pollack’s Rule. It states that the speedup achievable by adding computing elements to a processor is proportional to the number of added elements, raised to the power of (1-1/D), where D is the dimension in which the processors are arranged. A three-dimensional arrangement of, say, 100 processors will give a greater boost than a two-dimensional arrangement of those same processors, due to reduced signal latency. The same kind of speedup can be achieved in our nervous and circulatory systems with a D of greater than three. A rule of thumb common in the halls of Intel was programmed into our bodies eons ago; the fractal arrangement of our biological sensors and the nerves that connect them are designed for speed. The brain represents the height of biological information processing and transmission. But for years, it’s been considered a noisy instrument. Neurons code information with binary electrical events called spikes, shocking one another like tiny batteries. Once a neuron receives enough input that its voltage passes a certain threshold, it will spike in turn, sending its signal to downstream neurons. Fluctuations in the summed output of the brain’s 100 billion neurons

of (1-1/D), where D is the dimension in which the processors are arranged. A three-dimensional arrangement of, say, 100 processors will give a greater boost than a two-dimensional arrangement of those same processors, due to reduced signal latency. The same kind of speedup can be achieved in our nervous and circulatory systems with a D of greater than three. A rule of thumb common in the halls of Intel was programmed into our bodies eons ago; the fractal arrangement of our biological sensors and the nerves that connect them are designed for speed. The brain represents the height of biological information processing and transmission. But for years, it’s been considered a noisy instrument. Neurons code information with binary electrical events called spikes, shocking one another like tiny batteries. Once a neuron receives enough input that its voltage passes a certain threshold, it will spike in turn, sending its signal to downstream neurons. Fluctuations in the summed output of the brain’s 100 billion neurons, as measured by an electroencephalogram, or EEG, are much smaller than the amplitude of individual spikes, and were long thought to be epiphenomenal: pointers to various brain states, but not an information-carrying signal in itself. In other words, noise. Slow oscillations in the brain are coherent over large anatomical distances, in the same way you can hear the bass from your neighbor’s sound system better than the treble. Yet, as we saw with genetic expression, interactions among many discrete elements can be incredibly useful. It’s becoming clear that the so-called noise seen in an EEG is actually an important signal, and one that is crucial to neural computation. The fluctuation of the summed output of the brain’s neurons feeds back to affect the resting potential of those neurons, bringing them closer to or farther from spike threshold. Slow oscillations (as found in drowsy or sleeping animals) are coherent over large anatomical distances, in the same way you can hear the bass from your neighbor’s sou

, as measured by an electroencephalogram, or EEG, are much smaller than the amplitude of individual spikes, and were long thought to be epiphenomenal: pointers to various brain states, but not an information-carrying signal in itself. In other words, noise. Slow oscillations in the brain are coherent over large anatomical distances, in the same way you can hear the bass from your neighbor’s sound system better than the treble. Yet, as we saw with genetic expression, interactions among many discrete elements can be incredibly useful. It’s becoming clear that the so-called noise seen in an EEG is actually an important signal, and one that is crucial to neural computation. The fluctuation of the summed output of the brain’s neurons feeds back to affect the resting potential of those neurons, bringing them closer to or farther from spike threshold. Slow oscillations (as found in drowsy or sleeping animals) are coherent over large anatomical distances, in the same way you can hear the bass from your neighbor’s sound system better than the treble. This is how the brain may be facilitating communication between disparate brain areas: If an individual spike is timed with the crest of the slow amplitude fluctuation, it will have a bigger effect downstream than if it is timed with a trough. Neurons are somehow coordinating themselves to generate self-directed, global feedback that serves to adaptively boost even sub-detectable signals: No informational signal is wasted. In fact, it is an open question whether the idea of “waste” can even be properly defined in the context of the brain. Theoretical neuroscientist Tony Bell argues that the hallmark of biological computation is that information flows across multiple hierarchies of complexity, bubbling up from microscopic to macroscopic levels and back down again. Simpler structures (like neurons) communicate with more complex structures (like areas of the brain), and vice versa. Computations are occurring on and between every level, from molecules to cells to organisms as a w

nd system better than the treble. This is how the brain may be facilitating communication between disparate brain areas: If an individual spike is timed with the crest of the slow amplitude fluctuation, it will have a bigger effect downstream than if it is timed with a trough. Neurons are somehow coordinating themselves to generate self-directed, global feedback that serves to adaptively boost even sub-detectable signals: No informational signal is wasted. In fact, it is an open question whether the idea of “waste” can even be properly defined in the context of the brain. Theoretical neuroscientist Tony Bell argues that the hallmark of biological computation is that information flows across multiple hierarchies of complexity, bubbling up from microscopic to macroscopic levels and back down again. Simpler structures (like neurons) communicate with more complex structures (like areas of the brain), and vice versa. Computations are occurring on and between every level, from molecules to cells to organisms as a whole. There is a good deal of evidence that even the subcellular compartments within neurons are doing their own computations. Most recently, a study1 published in Nature in October 2013 showed that activity within dendrites (a compartment representing a neuron’s “input”) shapes the information processed by that neuron. Given this multi-level information flow, Bell argues that noise simply cannot be defined: Deviations from expectation should be interpreted as meaningful communication at another level of the complexity hierarchy. This information flow is not restricted to the brain, and can also be observed, for example, in epigenetics. Bell says this kind of dynamic multidirectional information flow is what defines life. Artificial intelligence, when it arrives, may not be built from silicon, but repurposed biology. Before we get there, though, we will need a vastly different approach to science in order to understand the higher-order, emergent capabilities of nature’s self-organizing structures. While biomi

hole. There is a good deal of evidence that even the subcellular compartments within neurons are doing their own computations. Most recently, a study1 published in Nature in October 2013 showed that activity within dendrites (a compartment representing a neuron’s “input”) shapes the information processed by that neuron. Given this multi-level information flow, Bell argues that noise simply cannot be defined: Deviations from expectation should be interpreted as meaningful communication at another level of the complexity hierarchy. This information flow is not restricted to the brain, and can also be observed, for example, in epigenetics. Bell says this kind of dynamic multidirectional information flow is what defines life. Artificial intelligence, when it arrives, may not be built from silicon, but repurposed biology. Before we get there, though, we will need a vastly different approach to science in order to understand the higher-order, emergent capabilities of nature’s self-organizing structures. While biomimicry holds incredible promise, perhaps in so assiduously copying the physical design of systems we are missing the point: Form is transient in Nature, cast to meet shifting needs in a given niche. Determining the rules by which biology struck upon these ingenious solutions in the first place will spark the true revolution. Kelly Clancy studied physics at MIT, then worked as an itinerant astronomer for several years before serving with the Peace Corps in Turkmenistan. She is currently a National Science Foundation fellow studying neuroscience at UC Berkeley. 1. Smith, S., et al Dendritic spikes enhance stimulus selectivity in cortical neurons in vivo. Nature 503, 115-120 (2013).

micry holds incredible promise, perhaps in so assiduously copying the physical design of systems we are missing the point: Form is transient in Nature, cast to meet shifting needs in a given niche. Determining the rules by which biology struck upon these ingenious solutions in the first place will spark the true revolution. Kelly Clancy studied physics at MIT, then worked as an itinerant astronomer for several years before serving with the Peace Corps in Turkmenistan. She is currently a National Science Foundation fellow studying neuroscience at UC Berkeley. 1. Smith, S., et al Dendritic spikes enhance stimulus selectivity in cortical neurons in vivo. Nature 503, 115-120 (2013).

The red backed shrike - also known as the "butcher bird" Following months of secrecy, hushed conversations, cloaks and daggers we can at last reveal that there is a new bird nesting in England. The red backed shrike last bred in the UK over in East Anglia in the early 1990s. But it has now returned to breed on Dartmoor with a hardy pair raising three youngsters. They are fascinating birds. I saw one of the last breeding pairs in the late eighties over in Suffolk. I clearly recall, even after 20 years, the male perched on a thorn bush gently flexing its silky black talons. Although they are passerines, in the same group of birds as our robins and blackbirds, they are also keen-eyed, sharp-billed predators that eagerly hunt small mammals, large insects and lizards. This is remarkable for a bird no bigger than your hand. They also have a habit that would see them at home in a 70s Hammer House of Horror flick. After catching their prey they often store it for later by impaling the hapless victim on a spike, be that a thorn or barbed wire fence. This rather gothic behaviour gave rise to their widespread title as "butcher birds". If you go back 50 years, red backed shrikes were not uncommon in England. Their general decline is something of a mystery, but the population is very much on the edge of its European range. Dartmoor - an ideal "bridgehead" for the species to re-colonise But we do know, that as they became scarcer their eventual fate was exacerbated by the unwanted attention of egg collectors who, in their fevered obsessions appeared to prize the shrikes' eggs above those of other birds. Although egg collecting has been consigned largely to a paltry footnote in the history books, there are still a small number of people willing to go to great lengths to lay their hairy palms on the eggs of rare species. And shrikes, we believe, are still near the top of their lists. The first news that the shrikes had settled came back in May 2010. Knowing they were immediately under threat, the RSPB, local birders from the Dar

at a thorn or barbed wire fence. This rather gothic behaviour gave rise to their widespread title as "butcher birds". If you go back 50 years, red backed shrikes were not uncommon in England. Their general decline is something of a mystery, but the population is very much on the edge of its European range. Dartmoor - an ideal "bridgehead" for the species to re-colonise But we do know, that as they became scarcer their eventual fate was exacerbated by the unwanted attention of egg collectors who, in their fevered obsessions appeared to prize the shrikes' eggs above those of other birds. Although egg collecting has been consigned largely to a paltry footnote in the history books, there are still a small number of people willing to go to great lengths to lay their hairy palms on the eggs of rare species. And shrikes, we believe, are still near the top of their lists. The first news that the shrikes had settled came back in May 2010. Knowing they were immediately under threat, the RSPB, local birders from the Dartmoor Study Group and Forestry Commission mounted a huge operation to protect the birds. It's a good job we did, for within weeks the site received its first visit from known egg collectors. Who knows what was going through their minds, but we feel the protection we afforded the site was enough to dissuade them from satisfying their cravings. Nowadays, to be caught collecting carries a £5,000 per egg fine and possible custodial sentence. The watch, 24-hours a day, seven days a week, carried on throughout the summer. The team involved grew remarkably close to the birds, their behaviour, their favourite hunting grounds, the tree each bird preferred. When I visited back in early August I was impressed by the studied concentration of the people involved. To remain fixed on one spot for any length of time is no mean feat. Finally, after many anxious days in August, the youngsters appeared. Three in all, enthusiastically tended by their proud parents. While this was a relief, it meant no let-up in the protection op

tmoor Study Group and Forestry Commission mounted a huge operation to protect the birds. It's a good job we did, for within weeks the site received its first visit from known egg collectors. Who knows what was going through their minds, but we feel the protection we afforded the site was enough to dissuade them from satisfying their cravings. Nowadays, to be caught collecting carries a £5,000 per egg fine and possible custodial sentence. The watch, 24-hours a day, seven days a week, carried on throughout the summer. The team involved grew remarkably close to the birds, their behaviour, their favourite hunting grounds, the tree each bird preferred. When I visited back in early August I was impressed by the studied concentration of the people involved. To remain fixed on one spot for any length of time is no mean feat. Finally, after many anxious days in August, the youngsters appeared. Three in all, enthusiastically tended by their proud parents. While this was a relief, it meant no let-up in the protection operation. Being the only pair, they are hugely vulnerable and the slightest disturbance could spell disaster. And we still felt it right to maintain secrecy to give the newly fledged young the very best start. But now, with the family days away from their migration south, we decided to lift the lid on this remarkable operation, not least to share the good news and to pay thanks to all those who have willingly given up many hundreds of hours to watch over the shrikes. And next year? Well, we hope the birds fare well in their African wintering grounds and return to breed again in 2011. And we hope their young return to breed as well. Dartmoor is an ideal bridgehead for them to re-colonise. Conservation organisations and landowners have worked hard over the years to make the moor a welcoming place for wildlife, as this success bears witness. Who knows, if all goes well, give it 10 years and you might have butcher birds near you. Tony Whitehead is the RSPB press officer for the South West.

eration. Being the only pair, they are hugely vulnerable and the slightest disturbance could spell disaster. And we still felt it right to maintain secrecy to give the newly fledged young the very best start. But now, with the family days away from their migration south, we decided to lift the lid on this remarkable operation, not least to share the good news and to pay thanks to all those who have willingly given up many hundreds of hours to watch over the shrikes. And next year? Well, we hope the birds fare well in their African wintering grounds and return to breed again in 2011. And we hope their young return to breed as well. Dartmoor is an ideal bridgehead for them to re-colonise. Conservation organisations and landowners have worked hard over the years to make the moor a welcoming place for wildlife, as this success bears witness. Who knows, if all goes well, give it 10 years and you might have butcher birds near you. Tony Whitehead is the RSPB press officer for the South West.

Accession Number : AD0704541 Title : BARRIER ISLANDS OF THE NORTHERN GULF OF MEXICO COAST: SEDIMENT SOURCE AND DEVELOPMENT. Descriptive Note : Technical rept., Corporate Author : LOUISIANA STATE UNIV BATON ROUGE COASTAL STUDIES INST Personal Author(s) : Kwon,Hyuck J. Report Date : 31 DEC 1969 Pagination or Media Count : 61 Abstract : The evolution of barrier islands along the northern Gulf of Mexico coast is directly related to source of sediments and littoral processes. Johnson formulated his hypothesis on barrier island formation in 1919, and his theory prevailed for several decades. Johnson's theory resulted from consideration of only two dimensions normal to the coastline; a third, longshore drift, was not regarded as critical for the initiation of barrier island development. In this study, which is confined to the northern Gulf coast, major sources of sediment supply and transportation patterns of barrier forming sand were examined, along with results of recent oceanographic investigations in the Gulf of Mexico. This study is based on a comprehensive survey of the literature, maps, and marine charts, which were correlated with field observations. To obtain a perspective, only gross forms and processes of barrier development were considered. Evidence indicates that Santa Rosa Island, Mississippi Sound, and Bolivar Peninsula barriers developed downdrift of sediment-supplying coasts of Quaternary age. These barriers evolved with the Recent rise of sea level to its present stand. Apalachicola barriers formed on the flanks of the Pleistocene deltaic plain. Coasts such as the stretch between Destin and Panama City, Florida, and the zero-energy coast of Florida do not have barrier islands. In these cases the modern shoreline is abutted against Pleistocene deposits which are the local source of sediments. (Author) Descriptors : (*COASTAL REGIONS, MEXICO GULF), (*ISLANDS, SEDIMENTATION), SOURCES, TRANSPORT PROPERTIES, SAND, DEPOSITS, ESTUARIES, GEOLOGIC AGE DETERMINATION, DELTAS, OCEAN WAVES, TIDES, FLORIDA Subject C

Mexico. This study is based on a comprehensive survey of the literature, maps, and marine charts, which were correlated with field observations. To obtain a perspective, only gross forms and processes of barrier development were considered. Evidence indicates that Santa Rosa Island, Mississippi Sound, and Bolivar Peninsula barriers developed downdrift of sediment-supplying coasts of Quaternary age. These barriers evolved with the Recent rise of sea level to its present stand. Apalachicola barriers formed on the flanks of the Pleistocene deltaic plain. Coasts such as the stretch between Destin and Panama City, Florida, and the zero-energy coast of Florida do not have barrier islands. In these cases the modern shoreline is abutted against Pleistocene deposits which are the local source of sediments. (Author) Descriptors : (*COASTAL REGIONS, MEXICO GULF), (*ISLANDS, SEDIMENTATION), SOURCES, TRANSPORT PROPERTIES, SAND, DEPOSITS, ESTUARIES, GEOLOGIC AGE DETERMINATION, DELTAS, OCEAN WAVES, TIDES, FLORIDA Subject Categories : Physical and Dynamic Oceanography Distribution Statement : APPROVED FOR PUBLIC RELEASE

ategories : Physical and Dynamic Oceanography Distribution Statement : APPROVED FOR PUBLIC RELEASE

September 22, 2012 A new study conducted by the New York University of Medicine reports that packaged food is directly correlated to the obesity levels rising in American children because of their exposure to Bisphenol A (BPA). According to the National Health and Nutrition Examination Survey from 2003, 92.6 % of children 6 years and older had obviously measurable levels detected in tested urine. The study also concludes that BPA disrupts other multiple metabolic mechanisms. BPA has been identified as causation for recent early pubescent development in our children. Between the ages of 5 – 7 is the new average pubescent age, wherein this physiological change used to occur several years later just a generation ago. BPA is a highly toxic estrogen accelerator that is used in all plastic products commercially produced. The chemical mimics natural estrogen when leeched into the body. It offsets natural estrogen levels, causing the body to hasten its pubescent generation. Nearly all children are exposed to this chemical through plastic toys, pacifiers, bottles, sippy cups. Its influence on natural hormone distribution within the body has proven to be incredibly damaging. In April of this year, GlobalData surmised that manufacturers would produce 4.7 million metric tons of BPA to be used in plastics worldwide. While the Food and Drug Administration (FDA) has banned its use in certain children’s products, it is widely used in packaging processed foods. In fact, the FDA claims that there is not enough convincing evidence to support the banning of BPA from use in food products, plastic packaging and personal care products. The FDA also asserted that there is insufficient scientific proof to justify restricting BPA’s use. Other chemicals linked to obesity in humans are: • Monosodium glutamate (MSG) • Pthalates (used in plastics) • PFOA (used in Teflon) also are harmful to the human immune system, liver and thyroid • Corn fed cows has higher levels of saturated fat in their beef • Arsenic (fed to pigs and chickens) affects t

mical through plastic toys, pacifiers, bottles, sippy cups. Its influence on natural hormone distribution within the body has proven to be incredibly damaging. In April of this year, GlobalData surmised that manufacturers would produce 4.7 million metric tons of BPA to be used in plastics worldwide. While the Food and Drug Administration (FDA) has banned its use in certain children’s products, it is widely used in packaging processed foods. In fact, the FDA claims that there is not enough convincing evidence to support the banning of BPA from use in food products, plastic packaging and personal care products. The FDA also asserted that there is insufficient scientific proof to justify restricting BPA’s use. Other chemicals linked to obesity in humans are: • Monosodium glutamate (MSG) • Pthalates (used in plastics) • PFOA (used in Teflon) also are harmful to the human immune system, liver and thyroid • Corn fed cows has higher levels of saturated fat in their beef • Arsenic (fed to pigs and chickens) affects the thyroid gland • Pharmaceuticals and medications in public water supplies negatively affect the natural chemical make-up of our bodies The claim by recent a recent study that obesity is linked to IQ, which was funded by the pharmaceutical industry serves to purvey the ideal that drugs are the answer to America’s weight problem. By determining the metabolic syndrome rate in a teenager, it is suggested that their cognitive brain function is compromised by their body mass index (BMI). The author of this study recommends using methods to develop a classification for overweight children in America so that the psychiatric industry can work together with the pharmaceutical corporations to develop drugs. Young people have been targeted as having a propensity toward becoming obese in rural areas. It was also noted that ethnicity played a part in the likelihood of becoming overweight. Blacks and Hispanics, according to the study, have a poor diet and are physically isolated, and do not necessarily have access to heal

he thyroid gland • Pharmaceuticals and medications in public water supplies negatively affect the natural chemical make-up of our bodies The claim by recent a recent study that obesity is linked to IQ, which was funded by the pharmaceutical industry serves to purvey the ideal that drugs are the answer to America’s weight problem. By determining the metabolic syndrome rate in a teenager, it is suggested that their cognitive brain function is compromised by their body mass index (BMI). The author of this study recommends using methods to develop a classification for overweight children in America so that the psychiatric industry can work together with the pharmaceutical corporations to develop drugs. Young people have been targeted as having a propensity toward becoming obese in rural areas. It was also noted that ethnicity played a part in the likelihood of becoming overweight. Blacks and Hispanics, according to the study, have a poor diet and are physically isolated, and do not necessarily have access to healthy food. The World Health Organization (WHO) have asserted that American over-consumption of food is a drain on global resources and unsustainable. Although Americans only account for 6% of the global population, more than a third of them are considered obese. WHO would like the average global body weight to be near emaciated levels to conserve food stores and reduce the human impact on the planet. Michelle Obama has remarked that the growing number of obese children in America is a threat to national security. Endocrinologist Robert Lustig of the University of California, San Francisco observes, “This epidemic of obese 6-month-olds. Since they’re eating only formula or breast milk, and never exactly got a lot of exercise, the obvious explanations for obesity don’t work for babies. You have to look beyond the obvious.” Early life exposure to traces of chemicals and hormone-mimicking pollutants, such as BPA, in the environment act on genes in the developing fetus and newborns and turn more precursor cells int

thy food. The World Health Organization (WHO) have asserted that American over-consumption of food is a drain on global resources and unsustainable. Although Americans only account for 6% of the global population, more than a third of them are considered obese. WHO would like the average global body weight to be near emaciated levels to conserve food stores and reduce the human impact on the planet. Michelle Obama has remarked that the growing number of obese children in America is a threat to national security. Endocrinologist Robert Lustig of the University of California, San Francisco observes, “This epidemic of obese 6-month-olds. Since they’re eating only formula or breast milk, and never exactly got a lot of exercise, the obvious explanations for obesity don’t work for babies. You have to look beyond the obvious.” Early life exposure to traces of chemicals and hormone-mimicking pollutants, such as BPA, in the environment act on genes in the developing fetus and newborns and turn more precursor cells into fat cells. These chemicals cause the cells to hoard nutrients, directly causing weight gain in infants. They may even cause severe alterations in the body’s metabolic rate.

o fat cells. These chemicals cause the cells to hoard nutrients, directly causing weight gain in infants. They may even cause severe alterations in the body’s metabolic rate.

Osteoarthritis symptoms of the hand can include difficulty bending and flexing your fingers, joint pain, and morning stiffness. Along with joint swelling and crepitus, common with finger arthritis, Heberden’s nodes can also appear. Heberden’s nodes are growths of bone on the distal interphalangeal joints (DIPs). These bumps can be a clear indication of hand osteoarthritis. Dr. William Heberden (1710 – 1801) was an english doctor who first described these bumps: “What are those little hard knobs, about the size of a small pea, which are frequently seen upon the fingers, particularly a little below the top near the joint? They have no connection with the gout, being found in persons who never had it: they con- tinue for life: and being hardly ever attended with pain, or disposed to become sore, are rather un- sightly than inconvenient, though they must be some little hindrance to the free use of the fingers.” Dr. Heberden was ahead of his time. He didn’t believe in blood-letting, sweating, and purging – all common treatment options during that day and age. He was known as the “Father of Observation”. An ice pack or finger splint can help.

(b Epsom, Surrey, 13 Dec. 1903; d Fawley Bottom, Buckinghamshire, nr. Henley-on-Thames, Oxfordshire, 28 June 1992). English painter, printmaker, draughtsman, designer, and writer. He reluctantly became an articled clerk in his father's legal firm, but took up the study of art after his father's death in 1926, first at the Richmond School of Art and then at the Royal College of Art. From 1928 to 1933 he wrote as an art critic for the Listener and the Nation and was among the first to recognize such contemporaries as William Coldstream, Ivon Hitchens, Victor Pasmore, and Ceri Richards. By the mid-1930s he was one of the leading British abstract artists, but by the end of the decade he had become disillusioned with non-representational art and reverted to naturalism. He concentrated on landscape and architectural views in an emotionally charged style that continued the English Romantic tradition (see Neo-Romanticism). Some of his finest works were done as an Official War Artist when he made pictures of bomb-damaged buildings. A similar stormy atmosphere pervades his famous views of country houses of the same period. Piper's work diversified in the 1950s and he became recognized as one of the most versatile British artists of his generation. He did much work as a designer of stage decor and of stained glass (notably at Coventry Cathedral) and was a prolific printmaker. In addition he made book illustrations and designed pottery and textiles. As a writer he is probably best known for his book British Romantic Artists (1942). He also compiled architectural guidebooks to several English counties, usually in collaboration with the poet John Betjeman.

Phlebotomy Jobs: An Overview Phlebotomy refers to the medical practice that revolves around extracting, essaying and experimenting blood. Usually, blood is extracted from human bodies for 3 main purposes. This can be for transfusion or donation and it can even be to test the presence of diseases within the human body. The technicians who get involved in extracting blood are referred to as phlebotomists. They are bound to make use of sterilized needles in order to extract the blood from the human veins. This blood drawn is further stored in vials for later essaying. Further to this extraction, the phlebotomist cleans up the area with cotton and sterile pads. A bandage is sometimes placed in the perforated area to stop bleeding. Phlebotomists who work at clinical laboratories get involved in essaying blood samples in depth. They try to understand the abnormalities present in the blood cells and further conduct experiments with it. Usually such personnel hold Bachelor’s degree in the field of medicine, anatomy and the like. To practice independently, they might also need to pass state conducted license examination and this might vary by location. Phlebotomists who work at veterinary clinics deal with blood samples of animals. They get involved in analyzing the samples of animals and defying the abnormalities in the blood of different animals in depth. Phlebotomists who work at research laboratories often get involved in blood analysis and discovery of new medications. This requires a doctoral degree in biology, chemistry or medicine. The most common advantages associated with Phlebotomy jobs are: * Getting into the entry level position is easy and requires minimal training in this arena. * The demand for Phlebotomists is usually unaffected by recession. * Growth in this arena would be easily possible provided the venture is associated with continuous education. Phlebotomy Jobs: Current Trends Currently, there is a boom for phlebotomy jobs, especially for individuals with good education, skills and training. The bulk

nd the like. To practice independently, they might also need to pass state conducted license examination and this might vary by location. Phlebotomists who work at veterinary clinics deal with blood samples of animals. They get involved in analyzing the samples of animals and defying the abnormalities in the blood of different animals in depth. Phlebotomists who work at research laboratories often get involved in blood analysis and discovery of new medications. This requires a doctoral degree in biology, chemistry or medicine. The most common advantages associated with Phlebotomy jobs are: * Getting into the entry level position is easy and requires minimal training in this arena. * The demand for Phlebotomists is usually unaffected by recession. * Growth in this arena would be easily possible provided the venture is associated with continuous education. Phlebotomy Jobs: Current Trends Currently, there is a boom for phlebotomy jobs, especially for individuals with good education, skills and training. The bulk of phlebotomy jobs seem to be occupied by the technicians at the laboratories who are associated with drawing human blood. Other phlebotomy jobs are also available at veterinary clinics and research laboratories. Individuals can get into the medical industry as phlebotomists with a high school diploma. However, there are employers who ask for certifications from differentiated medical schools or for associate degrees. Novices usually get training from either experienced phlebotomists or from nurses.

of phlebotomy jobs seem to be occupied by the technicians at the laboratories who are associated with drawing human blood. Other phlebotomy jobs are also available at veterinary clinics and research laboratories. Individuals can get into the medical industry as phlebotomists with a high school diploma. However, there are employers who ask for certifications from differentiated medical schools or for associate degrees. Novices usually get training from either experienced phlebotomists or from nurses.

The name moonshine was taken from the term “moonlighter”, used by the English to describe the nighttime runners that smuggled brandy from France. Read more about the history of moonshine, and learn about how it’s made. Moonshine is a common term for home distilled alcohol; especially in places were the production is illegal. The illegal production of moonshine is usually associated with the Southern United States and Appalachia. Since my grandparents had a farm in the Appalachian Mountain Range, I am familiar with the making of moonshine. Not that I ever made any, I was just a child in the 1960’s, but I had kinfolks (as we call them in the south) who did make it. Now, I am not telling anyone to make moonshine. It is illegal and dangerous. Sloppily produced moonshine can be contaminated with toxins, mainly from the materials used in the construction of the still. Some folks use old car radiators for a condenser in their stills. The lead used to solder radiators and in some cases the glycol products from antifreeze are poisonous and potentially deadly. My family had a friend that was in a coma and suffered kidney damage after drinking contaminated moonshine. Thankfully, he lived but it could have easily gone the other direction. Moonshine is made from fermented corn mash distilled in a cooker. The name moonshine was taken from the term “moonlighter” used by the English to describe the nighttime runners that smuggled brandy from France. After World War I, the agricultural prices dropped so during Prohibition, many American farmers turned to making moonshine as a way to support their families. Cosby, Tennessee was known as the “Moonshine Capital of the World”. In the 1960’s it was claimed there were over 200 stills operating on any given day, each averaging 20 gallons a day. It was also locally claimed that they ran moonshine to Atlanta, Knoxville, Chattanooga and Asheville, as well as some unnamed northern cities. The first thing you need before you can make moonshine is a still. A typical mountain still uses a ston

eeze are poisonous and potentially deadly. My family had a friend that was in a coma and suffered kidney damage after drinking contaminated moonshine. Thankfully, he lived but it could have easily gone the other direction. Moonshine is made from fermented corn mash distilled in a cooker. The name moonshine was taken from the term “moonlighter” used by the English to describe the nighttime runners that smuggled brandy from France. After World War I, the agricultural prices dropped so during Prohibition, many American farmers turned to making moonshine as a way to support their families. Cosby, Tennessee was known as the “Moonshine Capital of the World”. In the 1960’s it was claimed there were over 200 stills operating on any given day, each averaging 20 gallons a day. It was also locally claimed that they ran moonshine to Atlanta, Knoxville, Chattanooga and Asheville, as well as some unnamed northern cities. The first thing you need before you can make moonshine is a still. A typical mountain still uses a stone furnace for heat and a metal still for fermenting and heating the mash. Large barrels are used to collect the steam and for condensing the alcohol. It is always a smart moonshiner who locates his still next to a mountain stream where good cold water can be easily piped in to condense the steam from the liquor. - 50 lb of cornmeal - 200lb of sugar - 200 gallons of water - 12 oz of yeast. A hint: Don’t buy your sugar all in one place because it is a sure sign to the “revenuers” that you are going to make moonshine. - First carry all your supplies up to your mountain hideout. Have someone else there to keep the still nice and hot. - Bring the cornmeal to a boil add yeast and all your sugar to ferment the mash. - When the mash stops bubbling it is cooked in the still and the stream is captured in a barrel filled with cold mountain stream water. - The steam is allowed to cool and condensed by running it though a long copper coil submerged in another barrel with water in a trough from the near by cold mountain st

e furnace for heat and a metal still for fermenting and heating the mash. Large barrels are used to collect the steam and for condensing the alcohol. It is always a smart moonshiner who locates his still next to a mountain stream where good cold water can be easily piped in to condense the steam from the liquor. - 50 lb of cornmeal - 200lb of sugar - 200 gallons of water - 12 oz of yeast. A hint: Don’t buy your sugar all in one place because it is a sure sign to the “revenuers” that you are going to make moonshine. - First carry all your supplies up to your mountain hideout. Have someone else there to keep the still nice and hot. - Bring the cornmeal to a boil add yeast and all your sugar to ferment the mash. - When the mash stops bubbling it is cooked in the still and the stream is captured in a barrel filled with cold mountain stream water. - The steam is allowed to cool and condensed by running it though a long copper coil submerged in another barrel with water in a trough from the near by cold mountain stream. - Once condensed. the clear liquor drips from the bottom of the still into a catch can – these are usually ½ gallon glass jars. Test your moonshine for alcohol content or proof by adding a small amount of gunpowder to it and igniting it. If it burns, and you are still alive, its proof is measured somewhere between 100 and 200 proof or 50% to 100% pure alcohol. Pour into jugs, old coffee cups or mason jars and enjoy. Will get the entire gang drunk or I am not a good old southern girl. Just remember this was only written for fun. Don’t let me see any of you out there making moonshine, and if you do don’t forget to invite me over.

ream. - Once condensed. the clear liquor drips from the bottom of the still into a catch can – these are usually ½ gallon glass jars. Test your moonshine for alcohol content or proof by adding a small amount of gunpowder to it and igniting it. If it burns, and you are still alive, its proof is measured somewhere between 100 and 200 proof or 50% to 100% pure alcohol. Pour into jugs, old coffee cups or mason jars and enjoy. Will get the entire gang drunk or I am not a good old southern girl. Just remember this was only written for fun. Don’t let me see any of you out there making moonshine, and if you do don’t forget to invite me over.

New microfluidic devices found to be effective method of in-vitro fertilization in mice Early research suggests the emerging technology could be viable option for IVF ANN ARBOR, Mich. -- Technology that more closely mirrors the natural fertilization process is showing promise as a new method of in-vitro fertilization, researchers at the University of Michigan Health System have found. The researchers found that microfluidics – an emerging area of physics and biotechnology that deals with the microscopic flow of fluids – can be used successfully for IVF in mice. They also found that lower total numbers and concentrations of sperm were required when using microfluidic channels instead of culture dishes. "This is an extension of the work we've done in recent years to use microfluidics to separate viable sperm from dead and immature sperm in order to maximize the potential chances of fertilizing an egg," says Gary D. Smith, Ph.D., associate professor of obstetrics and gynecology, urology, and physiology at the U-M Medical School. "Now that we are using microfluidics for fertilization, what you are starting to see is the whole IVF process happening on a chip," says Smith, senior author of a study in Human Reproduction and director of the Assisted Reproductive Technologies Laboratory and of the Gamete Cryopreservation Laboratory at the Comprehensive Cancer Center. IVF is a process in which eggs are removed from a woman's body and fertilized with sperm outside the body. Fertilized eggs are then placed in the woman's uterus, where they can develop as in a normal pregnancy. The study, published online in the journal Human Reproduction, suggests that among other uses, microfluidic channels could be used in some – but not all – instances when a common form of insemination, known as ICSI, otherwise would be employed. ICSI, which stands for intracytoplasmic sperm injection, involves a single sperm being injected directly into an egg, or oocyte. Smith says ICSI still will be used in many situations, particularly when other typ

M Medical School. "Now that we are using microfluidics for fertilization, what you are starting to see is the whole IVF process happening on a chip," says Smith, senior author of a study in Human Reproduction and director of the Assisted Reproductive Technologies Laboratory and of the Gamete Cryopreservation Laboratory at the Comprehensive Cancer Center. IVF is a process in which eggs are removed from a woman's body and fertilized with sperm outside the body. Fertilized eggs are then placed in the woman's uterus, where they can develop as in a normal pregnancy. The study, published online in the journal Human Reproduction, suggests that among other uses, microfluidic channels could be used in some – but not all – instances when a common form of insemination, known as ICSI, otherwise would be employed. ICSI, which stands for intracytoplasmic sperm injection, involves a single sperm being injected directly into an egg, or oocyte. Smith says ICSI still will be used in many situations, particularly when other types of fertilization have failed in the past, or when the man has an extremely low sperm count or motility. Smith does not think the use of microfluidics will replace ICSI, but he says it could offer another option to many couples whose situations do not require ICSI, a process that can cost an extra $1,500 to $2,500 in addition to standard IVF costs. "While ICSI bypasses all natural selection, the use of microfluidic channels more closely resembles in vivo insemination. The microfluidic environment also may possess conditions more suitable for efficient sperm-oocyte interaction than the culture dish," he says. During the early stages of the study, researchers found that, contrary to their initial hypothesis, a much lower fertilization rate was achieved with the microfluidic device (12 percent) than in culture dishes (43 percent). They then hypothesized that as sperm concentration is decreased, fertilization rates would improve in microchannels. At these lower concentrations, the combined fertilization rate wa

es of fertilization have failed in the past, or when the man has an extremely low sperm count or motility. Smith does not think the use of microfluidics will replace ICSI, but he says it could offer another option to many couples whose situations do not require ICSI, a process that can cost an extra $1,500 to $2,500 in addition to standard IVF costs. "While ICSI bypasses all natural selection, the use of microfluidic channels more closely resembles in vivo insemination. The microfluidic environment also may possess conditions more suitable for efficient sperm-oocyte interaction than the culture dish," he says. During the early stages of the study, researchers found that, contrary to their initial hypothesis, a much lower fertilization rate was achieved with the microfluidic device (12 percent) than in culture dishes (43 percent). They then hypothesized that as sperm concentration is decreased, fertilization rates would improve in microchannels. At these lower concentrations, the combined fertilization rate was significantly higher in microchannels (27 percent) than in culture dishes (10 percent). The authors note that the research has only been conducted on mice, and that more testing and possibly the development of auxiliary technology will be needed before IVF by microfluidics is a viable option for humans. Still, the research is very promising, says lead author Ronald S. Suh, M.D., now with Urology of Indiana LLC in Indianapolis who was a resident in the U-M Department of Urology when he wrote the paper. "There has been a large amount of research on almost every aspect of IVF. The exciting thing we're seeing here is going the potential of integration of all of these things. In the future, you will be able to take patients with low sperm counts, use microfluidics to select the best sperm, and achieve fertilization in one step," he says. "That integration is really what is going to make microfluidics change IVF." In addition to Smith and Suh, other authors of the paper are Dana A. Ohl, M.D., professor of urology

s significantly higher in microchannels (27 percent) than in culture dishes (10 percent). The authors note that the research has only been conducted on mice, and that more testing and possibly the development of auxiliary technology will be needed before IVF by microfluidics is a viable option for humans. Still, the research is very promising, says lead author Ronald S. Suh, M.D., now with Urology of Indiana LLC in Indianapolis who was a resident in the U-M Department of Urology when he wrote the paper. "There has been a large amount of research on almost every aspect of IVF. The exciting thing we're seeing here is going the potential of integration of all of these things. In the future, you will be able to take patients with low sperm counts, use microfluidics to select the best sperm, and achieve fertilization in one step," he says. "That integration is really what is going to make microfluidics change IVF." In addition to Smith and Suh, other authors of the paper are Dana A. Ohl, M.D., professor of urology at the U-M Medical School; Shuichi Takayama, Ph.D., assistant professor of biomedical engineering and of macromolecular science and engineering at the U-M College of Engineering; Xiaoyue Zhu, research fellow in biomedical engineering; and Nandita Phadke, research assistant in biomedical engineering. Portions of the research were supported by grants from the National Institutes of Health and the College of Engineering Technology Development Fund. U-M has applied for patents on the microfluidic technology involved in this study. Smith and Takayama have formed a company called Incept BioSystems and stand to profit from commercialization of the products. Source: Eurekalert & othersLast reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009 Published on PsychCentral.com. All rights reserved.

at the U-M Medical School; Shuichi Takayama, Ph.D., assistant professor of biomedical engineering and of macromolecular science and engineering at the U-M College of Engineering; Xiaoyue Zhu, research fellow in biomedical engineering; and Nandita Phadke, research assistant in biomedical engineering. Portions of the research were supported by grants from the National Institutes of Health and the College of Engineering Technology Development Fund. U-M has applied for patents on the microfluidic technology involved in this study. Smith and Takayama have formed a company called Incept BioSystems and stand to profit from commercialization of the products. Source: Eurekalert & othersLast reviewed: By John M. Grohol, Psy.D. on 21 Feb 2009 Published on PsychCentral.com. All rights reserved.

Individual differences | Methods | Statistics | Clinical | Educational | Industrial | Professional items | World psychology | The Academic Performance Index (API) is a measurement of academic achievement and progress of individual schools in California, United States. It is one of the main components of the Public Schools Accountability Act passed by the California legislature in 1999. API scores ranges from a low of 200 to a high of 1000. A numeric API score ranges from a low of 200 to a high of 1000. The interim statewide API performance target for all schools is 800. A school's growth is measured by how well it is moving toward or past that goal. An API score is calculated for all students in a school as well as numerous API scores for each subgroup at the school (such as by race, English Learner Status, students with disabilities, and socieconomically disadvantaged pupils). The API Statewide Rank score ranks a school with all schools in California based on API score, while the API Similar Schools score ranks a school with 100 other schools in the state with similar demographic profiles (including parent education level, poverty level, student mobility, student ethnicity). Each rank ranges from 1 to 10, with a score of 10 meaning that the school's API fell into the top 10%. Indicator of performanceEdit A school's score or placement on the API is designed to be an indicator of a school's performance level and is calculated annually by the California Department of Education, primarily based on CST and CAHSEE tests. Due to the API's heavy reliance on standardized testing (although some factors such as attendance and graduation rates are considered), many criticisms of standardized testing can also be leveled at the reliability and accuracy of API scores as an indicator of a school's level of "academic achievement." One criticism until recently was that a school's API score took no account of a school's student dropout rate. This created the incentive to let poorly performing students drop out, since this would in

nks a school with 100 other schools in the state with similar demographic profiles (including parent education level, poverty level, student mobility, student ethnicity). Each rank ranges from 1 to 10, with a score of 10 meaning that the school's API fell into the top 10%. Indicator of performanceEdit A school's score or placement on the API is designed to be an indicator of a school's performance level and is calculated annually by the California Department of Education, primarily based on CST and CAHSEE tests. Due to the API's heavy reliance on standardized testing (although some factors such as attendance and graduation rates are considered), many criticisms of standardized testing can also be leveled at the reliability and accuracy of API scores as an indicator of a school's level of "academic achievement." One criticism until recently was that a school's API score took no account of a school's student dropout rate. This created the incentive to let poorly performing students drop out, since this would increase a school's average test scores. SB 219 (Senator Darrell Steinberg, 2007) addressed this concern, however, by requiring schools' API scores to incorporate student dropout rates. These changes are expected to be implemented in 2011. The API is closely tied to monetary and incentive awards by setting Annual Percent Growth Targets for each school and whether the school met or exceeded this goal. The Public Schools Accountability Act also establishes The Immediate Intervention/Underperforming Schools Program and the Governor's High Achieving/Improving Schools Program. In addition, the API is used to determine Adequate Yearly Progress as a part of the No Child Left Behind Act. - Academic Performance Index (API) - Understanding the API - Public Schools Accountability Act (PSAA) - Google - public data: Education Statistics of California: Academic Performance Index (API) |This page uses Creative Commons Licensed content from Wikipedia (view authors).|

crease a school's average test scores. SB 219 (Senator Darrell Steinberg, 2007) addressed this concern, however, by requiring schools' API scores to incorporate student dropout rates. These changes are expected to be implemented in 2011. The API is closely tied to monetary and incentive awards by setting Annual Percent Growth Targets for each school and whether the school met or exceeded this goal. The Public Schools Accountability Act also establishes The Immediate Intervention/Underperforming Schools Program and the Governor's High Achieving/Improving Schools Program. In addition, the API is used to determine Adequate Yearly Progress as a part of the No Child Left Behind Act. - Academic Performance Index (API) - Understanding the API - Public Schools Accountability Act (PSAA) - Google - public data: Education Statistics of California: Academic Performance Index (API) |This page uses Creative Commons Licensed content from Wikipedia (view authors).|

|Home | About | Journals | Submit | Contact Us | Français| Classical αβ T cells protect the host by monitoring intracellular and extracellular proteins in a two-step process. The first step is protein degradation and combining with a major histocompatibility complex (MHC) molecule leading to surface expression of this amalgam (antigen processing). The second step is the interaction of the T cell receptor (TCR) with the MHC-peptide complex leading to signaling in the T cells (antigen recognition). The context for this interaction is a T cell-antigen presenting cell (APC) junction known as an immunological synapse if symmetric and stable and that we have referred to as a kinapse if it is asymmetric and mobile. The physiological recognition of ligand takes place most efficiently in the filamentous (F)-actin rich lamellipodium and is F-actin dependent in stages of formation, triggering and myosin II dependent for signal amplification. This review discussed how these concepts emerged from early studies on adhesion, signaling and cell biology of T cells. The adaptive immune system is a sensory organ that monitors our inner spaces for evidence of infection or cancer, regulates steady state microbiota and avoids self injury (Krogsgaard and Davis, 2005). The primary filter for this sensor is the dendritic cell (DC), which samples tissue spaces and interfaces for novel macromolecular information (Steinman et al., 2003). DC respond to tissues injury and detect conserved microbial structures leading to changes in DC signals to T lymphocyte (T cells), to shape an appropriate response (Trombetta and Mellman, 2005; West et al., 2004). The largest part of the information is in the form of proteins broken down into peptides that form complexes with surface molecules of the major histocompatibility complex (MHC-peptide complexes) that allow DCs to share this information with T cells expressing the T cell antigen receptors (TCR). An individual has a few hundred T cells that can detect any foreign MHC-peptide complex with single mol

, signaling and cell biology of T cells. The adaptive immune system is a sensory organ that monitors our inner spaces for evidence of infection or cancer, regulates steady state microbiota and avoids self injury (Krogsgaard and Davis, 2005). The primary filter for this sensor is the dendritic cell (DC), which samples tissue spaces and interfaces for novel macromolecular information (Steinman et al., 2003). DC respond to tissues injury and detect conserved microbial structures leading to changes in DC signals to T lymphocyte (T cells), to shape an appropriate response (Trombetta and Mellman, 2005; West et al., 2004). The largest part of the information is in the form of proteins broken down into peptides that form complexes with surface molecules of the major histocompatibility complex (MHC-peptide complexes) that allow DCs to share this information with T cells expressing the T cell antigen receptors (TCR). An individual has a few hundred T cells that can detect any foreign MHC-peptide complex with single molecule sensitivity (Irvine et al., 2002; Sykulev et al., 1996). This sensitivity evolved by necessity because although the DC may express up to a million MHC molecules, it also samples thousands of proteins, most of which are self-proteins (Trombetta and Mellman, 2005). Thus, each T cell that contacts a DC needs to sort through this huge complexity of ligands and then focus on a few tens or hundreds of ligands that bind the TCR. This ultrasensitive process is still poorly understood, but clues are being discovered at an accelerating rate such that some critical answers are on the horizon. In the 1980’s it was shown that antigen recognition and actin dependent adhesion were integrated processes (Dustin and Springer, 1989); in the 1990’s it was discovered that the actin rich lamellipodium was the most sensitive part of this sensitive cells (Valitutti et al., 1995a); and in the present decade we and others have begun to examine single molecule dynamics of TCR signaling complexes (Douglass and Vale, 2005). This re

ecule sensitivity (Irvine et al., 2002; Sykulev et al., 1996). This sensitivity evolved by necessity because although the DC may express up to a million MHC molecules, it also samples thousands of proteins, most of which are self-proteins (Trombetta and Mellman, 2005). Thus, each T cell that contacts a DC needs to sort through this huge complexity of ligands and then focus on a few tens or hundreds of ligands that bind the TCR. This ultrasensitive process is still poorly understood, but clues are being discovered at an accelerating rate such that some critical answers are on the horizon. In the 1980’s it was shown that antigen recognition and actin dependent adhesion were integrated processes (Dustin and Springer, 1989); in the 1990’s it was discovered that the actin rich lamellipodium was the most sensitive part of this sensitive cells (Valitutti et al., 1995a); and in the present decade we and others have begun to examine single molecule dynamics of TCR signaling complexes (Douglass and Vale, 2005). This review will describe the cellular context of TCR signaling reactions, which include an important niche based on F-actin rich lamellipodia that can be elaborated in motile and arrested cells. The TCR and adhesion molecules were identified by antibodies in the same burst of activity to discover the receptors involved in lymphocyte function by screening for inhibitors (Sanchez-Madrid et al., 1982; White et al., 1983). The last piece of the molecular puzzle, the structure of an MHC-peptide complex, was determined in 1987 (Bjorkman et al., 1987). This structure clarified the highly competitive nature of binding short peptides to the MHC molecule in a relatively stable manner (Babbitt et al., 1985). Thus, each TCR is locked into recognizing a small number of antigenic structures and each MHC molecule presents a single peptide. DCs use a limited numbers of any single MHC-peptide ligand to search through a vast repertoire of T cells. Thus, powerful mechanisms are needed to coordinate the search and response. Early work

view will describe the cellular context of TCR signaling reactions, which include an important niche based on F-actin rich lamellipodia that can be elaborated in motile and arrested cells. The TCR and adhesion molecules were identified by antibodies in the same burst of activity to discover the receptors involved in lymphocyte function by screening for inhibitors (Sanchez-Madrid et al., 1982; White et al., 1983). The last piece of the molecular puzzle, the structure of an MHC-peptide complex, was determined in 1987 (Bjorkman et al., 1987). This structure clarified the highly competitive nature of binding short peptides to the MHC molecule in a relatively stable manner (Babbitt et al., 1985). Thus, each TCR is locked into recognizing a small number of antigenic structures and each MHC molecule presents a single peptide. DCs use a limited numbers of any single MHC-peptide ligand to search through a vast repertoire of T cells. Thus, powerful mechanisms are needed to coordinate the search and response. Early work on the T cell signaling response to TCR-MHC-peptide interactions revealed rapid elevation of and protein kinase C activation and cytoplasmic Ca2+ down-stream of a tyrosine kinase cascade (Samelsonet al., 1986). Parallel studies on the adhesion molecule LFA-1 demonstrated that it was regulated by an F-actin and energy dependent mechanism that could be activated by phorbol esters (Marlin and Springer, 1987). LFA-1 was found to mediate adhesion by binding to a family of adhesion molecules including ICAM-1, whose expression reflects the innate immune activation of tissues (Dustin et al., 1986). Resting T cells are non-adhesive to ICAM-1 coated surfaces when freshly isolated from peripheral blood, but become more adhesive to ICAM-1 after triggering of TCR signaling (Dustin and Springer, 1989). The time course of adhesion activation closely followed the time course of TCR signaling: a process of “inside-out signaling” (Dustin and Springer, 1989). In the case of LFA-1, a candidate molecular mechanism for this activ

on the T cell signaling response to TCR-MHC-peptide interactions revealed rapid elevation of and protein kinase C activation and cytoplasmic Ca2+ down-stream of a tyrosine kinase cascade (Samelsonet al., 1986). Parallel studies on the adhesion molecule LFA-1 demonstrated that it was regulated by an F-actin and energy dependent mechanism that could be activated by phorbol esters (Marlin and Springer, 1987). LFA-1 was found to mediate adhesion by binding to a family of adhesion molecules including ICAM-1, whose expression reflects the innate immune activation of tissues (Dustin et al., 1986). Resting T cells are non-adhesive to ICAM-1 coated surfaces when freshly isolated from peripheral blood, but become more adhesive to ICAM-1 after triggering of TCR signaling (Dustin and Springer, 1989). The time course of adhesion activation closely followed the time course of TCR signaling: a process of “inside-out signaling” (Dustin and Springer, 1989). In the case of LFA-1, a candidate molecular mechanism for this activation was binding of talin to the cytoplasmic domain of LFA-1 (Smith et al., 2005). Talinis recruited to sites of LFA-1 interaction with ligands on APCs and this is a more sensitive process with respect to antigen dose than cytokine production or proliferation (Kupfer and Singer, 1989). The parallel field studying lymphocyte trafficking revealed that LFA-1 can also be acutely activated by G-protein coupled receptors that are associated with lymphocyte homing (Lawrence and Springer, 1991). Thus, LFA-1 regulation is a cornerstone in both body-wide navigation of lymphocytes through vascular interaction and the coordination of antigen recognition and strong, transient adhesion leading to the immunological synapse in tissues. Specific signaling pathways are required for inside out signaling from TCR to LFA-1. The adapter molecule ADAP and its partner SKAP-55 have been shown to contribute to about half of TCR triggered adhesion (Peterson et al., 2001). This process is integrated with F-actin at both the level of th

ation was binding of talin to the cytoplasmic domain of LFA-1 (Smith et al., 2005). Talinis recruited to sites of LFA-1 interaction with ligands on APCs and this is a more sensitive process with respect to antigen dose than cytokine production or proliferation (Kupfer and Singer, 1989). The parallel field studying lymphocyte trafficking revealed that LFA-1 can also be acutely activated by G-protein coupled receptors that are associated with lymphocyte homing (Lawrence and Springer, 1991). Thus, LFA-1 regulation is a cornerstone in both body-wide navigation of lymphocytes through vascular interaction and the coordination of antigen recognition and strong, transient adhesion leading to the immunological synapse in tissues. Specific signaling pathways are required for inside out signaling from TCR to LFA-1. The adapter molecule ADAP and its partner SKAP-55 have been shown to contribute to about half of TCR triggered adhesion (Peterson et al., 2001). This process is integrated with F-actin at both the level of the TCR signal as discussed below and directly through the interactions of ADAP through Ena-VASP family members, which are involved directly in actin polymerization and contribute to regulation of Arp2/3 (Krause et al., 2000). SKAP-55 forms a complex with RIAM (Menasche et al., 2007), which binds to active Rap-1, a small G-protein related to Ras that is required for regulation of adhesion in lymphocytes. Activation of Rap-1 downstream of tyrosine kinase cascades requires a guanine nucleotide exchange factor (GEF) called C3G. TCR signaling activates C3G by a cascade involving Vav, a GEF for Rac (Krawczyk et al., 2002). Recent evidence suggests that Rac activates the WAVE2 complex, which activates Abl and CrkL-C3G to increase active Rap1 (Nolz et al., 2008). The Rap-1-RIAM complex then contributes to activation of talin, which directly binds to the β2 cytoplasmic domain in the critical hinge region to activate and cluster LFA-1 (Smith et al., 2005; Tadokoro et al., 2003; Wegener et al., 2007). This pathway accoun

e TCR signal as discussed below and directly through the interactions of ADAP through Ena-VASP family members, which are involved directly in actin polymerization and contribute to regulation of Arp2/3 (Krause et al., 2000). SKAP-55 forms a complex with RIAM (Menasche et al., 2007), which binds to active Rap-1, a small G-protein related to Ras that is required for regulation of adhesion in lymphocytes. Activation of Rap-1 downstream of tyrosine kinase cascades requires a guanine nucleotide exchange factor (GEF) called C3G. TCR signaling activates C3G by a cascade involving Vav, a GEF for Rac (Krawczyk et al., 2002). Recent evidence suggests that Rac activates the WAVE2 complex, which activates Abl and CrkL-C3G to increase active Rap1 (Nolz et al., 2008). The Rap-1-RIAM complex then contributes to activation of talin, which directly binds to the β2 cytoplasmic domain in the critical hinge region to activate and cluster LFA-1 (Smith et al., 2005; Tadokoro et al., 2003; Wegener et al., 2007). This pathway accounts for the strong correlation of LFA-1 dependent cell-cell adhesion and talin accumulation at the interface. Another connection to F-actin is observed in the APC. DC mediated antigen presentation is an active process that requires small G-proteins of the Rac family and intact F-actin (Al-Alwan et al., 2003; Benvenuti et al., 2004). This may be in part due to the interaction if ICAM-1 with the actin cytoskeleton, in part via ERM family members. Norcross and Paul first discussed the idea of an immunological synapse with the main “synapse-like” features being a role for Ca2+ elevation, adhesion and directed secretion and polarity (Norcross, 1984). There are a handful of studies in the 1980’s and 90’s that provide quantitative data on cytoskeletal organization, secretory apparatus polarization and Ca2+ signaling in T cell conjugates with B cells e.g. (Geiger et al., 1982; Kupfer et al., 1986; Poenie et al., 1987), in addition to above mentioned studies on adhesion. The classical picture is of cell pairs with a T

ts for the strong correlation of LFA-1 dependent cell-cell adhesion and talin accumulation at the interface. Another connection to F-actin is observed in the APC. DC mediated antigen presentation is an active process that requires small G-proteins of the Rac family and intact F-actin (Al-Alwan et al., 2003; Benvenuti et al., 2004). This may be in part due to the interaction if ICAM-1 with the actin cytoskeleton, in part via ERM family members. Norcross and Paul first discussed the idea of an immunological synapse with the main “synapse-like” features being a role for Ca2+ elevation, adhesion and directed secretion and polarity (Norcross, 1984). There are a handful of studies in the 1980’s and 90’s that provide quantitative data on cytoskeletal organization, secretory apparatus polarization and Ca2+ signaling in T cell conjugates with B cells e.g. (Geiger et al., 1982; Kupfer et al., 1986; Poenie et al., 1987), in addition to above mentioned studies on adhesion. The classical picture is of cell pairs with a T cell stably appended onto the often-larger target cells like an apse on a building-which is the origin of the term synapse. In one study, a distinct annular adhesive domain and central secretory domains were resolved by electron microscopy (Schmidt et al., 1988), which foreshadows the later work by Kupfer. The molecular organization of these interfaces was not revealed until advances in imaging in the 1990’s led to the definition of discrete localization of TCR and LFA-1 and a more specific definition of immunological synapse was proposed (Dustin et al., 1998). Springer proposed in 1990 that LFA-1 and TCR would be segregated in adhesive interfaces because they are different sizes and it would be impossible for TCR to reach the MHC in a adhesive interface mediated by LFA-1 and it would be similarly difficult for LFA-1 to squeeze into an interface defined by the smaller CD2-CD58 adhesion system, which would in turn be ideal for the TCR (Springer, 1990). Springer further proposed that exclusion of large phosphat

cell stably appended onto the often-larger target cells like an apse on a building-which is the origin of the term synapse. In one study, a distinct annular adhesive domain and central secretory domains were resolved by electron microscopy (Schmidt et al., 1988), which foreshadows the later work by Kupfer. The molecular organization of these interfaces was not revealed until advances in imaging in the 1990’s led to the definition of discrete localization of TCR and LFA-1 and a more specific definition of immunological synapse was proposed (Dustin et al., 1998). Springer proposed in 1990 that LFA-1 and TCR would be segregated in adhesive interfaces because they are different sizes and it would be impossible for TCR to reach the MHC in a adhesive interface mediated by LFA-1 and it would be similarly difficult for LFA-1 to squeeze into an interface defined by the smaller CD2-CD58 adhesion system, which would in turn be ideal for the TCR (Springer, 1990). Springer further proposed that exclusion of large phosphatases like CD45 might be important for tyrosine phosphorylation down-stream of the tyrosine kinase cascade. This concept has been refined and tested and seems likely to be an important part of the signaling niche for the TCR (Choudhuri and van der Merwe, 2007; Varma et al., 2006). Springer didn’t speculate on the scale over which this segregation process would take place. The initial answers to this question were surprising. Kupfer examined fixed T cell-B cell conjugates and revealed a large central TCR cluster that was also rich in PKC-θ, defined as the central supramolecular activation cluster (cSMAC) (Monks et al., 1998)(Table 1). A ring of LFA-1-ICAM-1 interactions and talin surrounds this central cluster, defined as the peripheral supramolecular activation cluster (pSMAC). Each of these areas contained thousands of molecules in what was apparently a large non-covalent functional network-a supramolecular assembly. Kupfer later defined the distal supramolecular activation cluster as the outermost structure,

ases like CD45 might be important for tyrosine phosphorylation down-stream of the tyrosine kinase cascade. This concept has been refined and tested and seems likely to be an important part of the signaling niche for the TCR (Choudhuri and van der Merwe, 2007; Varma et al., 2006). Springer didn’t speculate on the scale over which this segregation process would take place. The initial answers to this question were surprising. Kupfer examined fixed T cell-B cell conjugates and revealed a large central TCR cluster that was also rich in PKC-θ, defined as the central supramolecular activation cluster (cSMAC) (Monks et al., 1998)(Table 1). A ring of LFA-1-ICAM-1 interactions and talin surrounds this central cluster, defined as the peripheral supramolecular activation cluster (pSMAC). Each of these areas contained thousands of molecules in what was apparently a large non-covalent functional network-a supramolecular assembly. Kupfer later defined the distal supramolecular activation cluster as the outermost structure, enriched in CD45, although this will be discussed further below. The distal pole complex was described by Burkhardt and may be important for sequestering specific negative regulators like SHP-1 (Cullinan et al., 2002). TCR microclusters will be discussed at length. Table I outlines the compartments associated with stable, antigen specific T cell-B cell conjugates. Parallel studies with supported planar bilayers presenting adhesion molecules revealed similar phenomena in which a single adhesion system would establish a cooperative supamolecular cluster and mixed systems would segregate into spatially discrete SMACs. We examined the organization of the CD2-CD58 and LFA-1-ICAM-1 interactions in contacts in Jurkat T cells on planar bilayers containing ICAM-1 and CD58 (Dustin et al., 1998). We proposed that the “specialized junction, cell polarization, and positional stability” of the symmetric contacts were similar to a neural synapse and proposed that stable T-APC interfaces should be defined as “immunological

enriched in CD45, although this will be discussed further below. The distal pole complex was described by Burkhardt and may be important for sequestering specific negative regulators like SHP-1 (Cullinan et al., 2002). TCR microclusters will be discussed at length. Table I outlines the compartments associated with stable, antigen specific T cell-B cell conjugates. Parallel studies with supported planar bilayers presenting adhesion molecules revealed similar phenomena in which a single adhesion system would establish a cooperative supamolecular cluster and mixed systems would segregate into spatially discrete SMACs. We examined the organization of the CD2-CD58 and LFA-1-ICAM-1 interactions in contacts in Jurkat T cells on planar bilayers containing ICAM-1 and CD58 (Dustin et al., 1998). We proposed that the “specialized junction, cell polarization, and positional stability” of the symmetric contacts were similar to a neural synapse and proposed that stable T-APC interfaces should be defined as “immunological synapses”. A planar bilayer based system using MHC-peptide complexes and LFA-1 fully recapitulated Kupfer’s findings and provided insight into the dynamics of these structures, which were not formed en bloc, but evolved from very distinct early intermediates by an F-actin dependent transport process (Grakoui et al., 1999)(Fig 1). The immunological synapse has an axis of radial symmetry with its center at the cSMAC (Fig 1). At the same time, we can view the synapse as having a direction of polarity along the length of this axis with a proximal and distal pole relative to the APC containing distinct molecules (Fig 1). The function of the immunological synapse pattern is most transparent for cytotoxic T cells where the F-actin free cSMAC serves as a secretory domain and the pSMAC serves as a retaining wall (Beal et al., 2008; Stinchcombe et al., 2006). The importance of directed secretion is supported by studies with human patients with deficiencies in granule transport to the synapse that lead to defects in kil

synapses”. A planar bilayer based system using MHC-peptide complexes and LFA-1 fully recapitulated Kupfer’s findings and provided insight into the dynamics of these structures, which were not formed en bloc, but evolved from very distinct early intermediates by an F-actin dependent transport process (Grakoui et al., 1999)(Fig 1). The immunological synapse has an axis of radial symmetry with its center at the cSMAC (Fig 1). At the same time, we can view the synapse as having a direction of polarity along the length of this axis with a proximal and distal pole relative to the APC containing distinct molecules (Fig 1). The function of the immunological synapse pattern is most transparent for cytotoxic T cells where the F-actin free cSMAC serves as a secretory domain and the pSMAC serves as a retaining wall (Beal et al., 2008; Stinchcombe et al., 2006). The importance of directed secretion is supported by studies with human patients with deficiencies in granule transport to the synapse that lead to defects in killing (Baetz et al., 1995). Stabilization of the pSMAC of CD4+ cytotoxic T lymphocyte (CTL) with a PKC-θ inhibitor quantified increased killing, the first evidence of for an advantage of an intact pSMAC (Beal et al., 2008). Structures similar to pSMACs also form between T cells in homotypic aggregates and are important for intensification of cytokine signals during T cell expansion (Sabatos et al., 2008). The symmetric immunological synapse may serve equally important functions in tolerance induction, priming and differentiation as discussed below. Between chemokine dependent extravasation and MHC-peptide dependent immunological synapse formation T cells rapidly migrate in DC networks of T cell zones (Bajenoff et al., 2006). Rapid migration by T cells can be fully reconstituted with solid phase CCL21, a CCR7 ligand, in vitro (Woolf et al., 2007). This involved polarization and formation of a leading edge that takes the form of a flattened lamellipodium on CCL21 and ICAM-1 coated surfaces (Huang and Dustin, unp