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Psychiatry The introduction of moral treatment was initiated independently by the French doctor Philippe Pinel and the English Quaker William Tuke. In 1792 Pinel became the chief physician at the Bicêtre Hospital. Patients were allowed to move freely about the hospital grounds, and eventually dark dungeons were replaced with sunny, well-ventilated rooms. Pinel's student and successor, Jean Esquirol (1772–1840), went on to help establish 10 new mental hospitals that operated on the same principles. Although Tuke, Pinel and others had tried to do away with physical restraint, it remained widespread into the 19th century. At the Lincoln Asylum in England, Robert Gardiner Hill, with the support of Edward Parker Charlesworth, pioneered a mode of treatment that suited "all types" of patients, so that mechanical restraints and coercion could be dispensed with — a situation he finally achieved in 1838. In 1839 Sergeant John Adams and Dr. John Conolly were impressed by the work of Hill, and introduced the method into their Hanwell Asylum, by then the largest in the country. The modern era of institutionalized provision for the care of the mentally ill, began in the early 19th century with a large state-led effort. In England, the Lunacy Act 1845 was an important landmark in the treatment of the mentally ill, as it explicitly changed the status of mentally ill people to patients who required treatment. All asylums were required to have written regulations and to have a resident qualified physician

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Psychiatry

Psychiatry In 1838, France enacted a law to regulate both the admissions into asylums and asylum services across the country. In the United States, the erection of state asylums began with the first law for the creation of one in New York, passed in 1842. The Utica State Hospital was opened approximately in 1850. Many state hospitals in the United States were built in the 1850s and 1860s on the Kirkbride Plan, an architectural style meant to have curative effect. At the turn of the century, England and France combined had only a few hundred individuals in asylums. By the late 1890s and early 1900s, this number had risen to the hundreds of thousands. However, the idea that mental illness could be ameliorated through institutionalization ran into difficulties. Psychiatrists were pressured by an ever-increasing patient population, and asylums again became almost indistinguishable from custodial institutions. In the early 1800s, psychiatry made advances in the diagnosis of mental illness by broadening the category of mental disease to include mood disorders, in addition to disease level delusion or irrationality. The 20th century introduced a new psychiatry into the world, with different perspectives of looking at mental disorders. For Emil Kraepelin, the initial ideas behind biological psychiatry, stating that the different mental disorders are all biological in nature, evolved into a new concept of "nerves", and psychiatry became a rough approximation of neurology and neuropsychiatry

Biology

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Psychiatry

Psychiatry Following Sigmund Freud's pioneering work, ideas stemming from psychoanalytic theory also began to take root in psychiatry. The psychoanalytic theory became popular among psychiatrists because it allowed the patients to be treated in private practices instead of warehoused in asylums. By the 1970s, however, the psychoanalytic school of thought became marginalized within the field. Biological psychiatry reemerged during this time. Psychopharmacology became an integral part of psychiatry starting with Otto Loewi's discovery of the neuromodulatory properties of acetylcholine; thus identifying it as the first-known neurotransmitter. Neuroimaging was first utilized as a tool for psychiatry in the 1980s. The discovery of chlorpromazine's effectiveness in treating schizophrenia in 1952 revolutionized treatment of the disorder, as did lithium carbonate's ability to stabilize mood highs and lows in bipolar disorder in 1948. Psychotherapy was still utilized, but as a treatment for psychosocial issues. In 1963, US president John F. Kennedy introduced legislation delegating the National Institute of Mental Health to administer Community Mental Health Centers for those being discharged from state psychiatric hospitals. Later, though, the Community Mental Health Centers focus shifted to providing psychotherapy for those suffering from acute but less serious mental disorders

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Psychiatry

Psychiatry Ultimately there were no arrangements made for actively following and treating severely mentally ill patients who were being discharged from hospitals, resulting in a large population of chronically homeless people suffering from mental illness. Controversy has often surrounded psychiatry, and the term anti-psychiatry was coined by psychiatrist David Cooper in 1967 and was later made popular by Thomas Szasz. The basic premise of anti-psychiatry is that: psychiatrists attempt to maliciously classify "normal" people as "deviant;" psychiatric treatments are ultimately more damaging than helpful to patients; and psychiatry's history involves (what may now be seen as) dangerous treatments, such as the frontal lobectomy (commonly called, a lobotomy). Several former patient groups have been formed often referring to themselves as "survivors." In 1973, the Rosenhan experiment was conducted to determine the validity of psychiatric diagnosis. Volunteers feigned hallucinations to enter psychiatric hospitals, and acted normally afterwards. They were diagnosed with psychiatric disorders and were given antipsychotic drugs. The study was conducted by psychologist David Rosenhan, a Stanford University professor, and published by the journal "Science" under the title "On being sane in insane places"

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Psychiatry

Psychiatry Additionally, the Church of Scientology (through one of its self-described "Humanitarian Efforts") created a "museum" in Los Angeles, CA (USA) which purports to show the evolution of the "evils" of psychiatry and psychology over time. The specific Scientology-related organization, the Citizens Commission on Human Rights (CCHR), is entirely devoted to the Anti-movement. That said, there has been a great deal of criticism about the veracity of specific information provided to the public and the conclusions drawn within the "exhibits."

Biology

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Psychiatry

McN5652 is a molecule that can be radiolabeled and then used as a radioligand in positron emission tomography (PET) studies. The [C]-(+)-enantiomer binds to the serotonin transporter. The radioligand is used for molecular neuroimaging and for imaging of the lungs. It was developed by Johnson & Johnson's McNeil Laboratories. According to McNeil, was among the strongest SRI ever reported at the time of its discovery (sub nM Ki). However, it is not completely 5-HT selective: the racemate has 5-HT=0.68, NA=2.9, and D=36.8nM, whereas (+)-enantiomer has 5-HT=0.39, NA=1.8, and D=23.5 nM. Paroxetine was listed as 5-HT=0.44 nM, NA=20, and DA=460nM in the same paper by the same authors. See for example: cited in PC44438935.

Biology

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McN5652

Mipomersen (INN; trade name Kynamro) is used to treat homozygous familial hypercholesterolemia and is administered by subcutaneous injection. There is a serious risk of liver damage from this drug and it can only be prescribed in the context of a risk management plan. Kynamro is used to treat homozygous familial hypercholesterolemia and is administered by injection. It cannot be freely prescribed; instead every person put on mipomersen is enrolled in a Risk Evaluation and Mitigation Strategies (REMS) program approved by the FDA. is pregnancy category B; women who are pregnant or intending to become pregnant should only use this drug if needed. It is unknown if it is secreted in human breast milk, but it was found to be secreted in the breast milk of rats. The drug is contraindicated in people with moderate to severe liver impairment, active liver diseases, and unexplained high levels of transaminase liver enzymes. The drug has a black box warning about the risk of liver damage; specifically it can cause elevations in the levels of transaminases and causes fatty liver disease. In clinical trials, 18% of subjects taking mipomersen stopped using the drug due to adverse effects; the most common adverse effects leading to discontinuation were injection site reactions, increases of transaminases, flu-like symptoms (fever, chills, abdominal pain, nausea, vomiting), and abnormal liver tests

Biology

https://en.wikipedia.org/wiki?curid=18978054

Mipomersen

Mipomersen Other adverse effects include: heart problems including angina and palpitations, edema, pain in legs or arms, headache, insomnia, and hypertension. Other drugs known for causing liver problems might add to mipomersen's risk of liver damage. No pharmacokinetic interactions have been described. binds to the messenger RNA coding for apolipoprotein B-100 (ApoB-100), a protein that is the main component of low-density lipoprotein (LDL) and very low-density lipoprotein (VLDL). As a consequence, the RNA is degraded by the enzyme ribonuclease H, and ApoB-100 is not translated. After subcutaneous injection, mipomersen reaches highest blood levels after 3 to 4 hours. It accumulates in the liver, which is convenient since apolipoprotein B predominantly acts there. Protein binding is over 90%. The molecule is slowly broken up by endonucleases and subsequently by exonucleases. After 24 hours, less than 4% of the degradation products are found in the urine, and overall half-life is 1 to 2 months. The compound is a 'second-generation' antisense oligonucleotide; the nucleotides are linked with phosphorothioate linkages rather than the phosphodiester linkages of RNA and DNA, and the sugar parts are deoxyribose in the middle part of the molecule and 2’-"O"-methoxyethyl-modified ribose at the two ends. These modifications make the drug resistant to degradation by nucleases, allowing it to be administered weekly

Biology

https://en.wikipedia.org/wiki?curid=18978054

Mipomersen

Mipomersen The complete sequence is portrayed below: The drug was discovered and developed to Phase 2 by Ionis Pharmaceuticals and subsequently licensed to Genzyme Corporation in 2008 by an auction bid. Isis earned an upfront payment of $325 million, with payments of a further $825 million if milestones are met. was rejected by the European Medicines Agency in 2012 and again in 2013 due to concerns about the liver and cardiovascular adverse effects. In January 2013, The United States Food and Drug Administration approved mipomersen for the treatment of homozygous familial hypercholesterolemia.

Biology

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Mipomersen

Tamga (genus) Tamga hamulifera is a disk-shaped fossil from Precambrian strata of the White Sea area, in Russia. The small (3–5 mm in length), disk-shaped fossil has seven hook-like isomers in a star-like arrangement in the clearly expressed peripheral undivided zone. "T. hamulifera" is probably a member of Proarticulata, as it is strongly similar to "Praecambridium sigillum" in the general shape, and the presence of hooklike isomers; "Tamga" is also similar to "Onega stepanovi" in the flattened body with a compact group of ledges-isomers in the central part encircled by an undivided zone. The fossils of "Tamga" could possibly be sclerites, for example, as sclerites of palaeoscolecids show a similar shape, a disk with a ring or rows of tubercles in the center. But the size of "Tamga"'s fossils is two orders of magnitude smaller than those of palaeoscolecid sclerites, and no mineralized sclerites of any sort have ever been found or diagnosed in the Vendian–Ediacaran communities. The generic name is taken from the Turkish word, "tamga", meaning seal or cattle brand. The specific name is a crasis compound word, taken from Latin, of "hamulus" (small hook), and the feminine form of "feros", "to bear." Thus, the scientific name can be translated as a "seal that bears small hooks."

Biology

https://en.wikipedia.org/wiki?curid=18985892

Tamga (genus)

Phytomer Phytomers are functional units of a plant, continually produced by root and shoot meristems throughout a plant's vegetative life-cycle. The phytomer unit originates at the shoot (or root) apex, and a typical phytomer consists of a node to which a leaf is attached, a subtending internode, and an axillary bud at the base of the leaf. Each component of a phytomer can continue to differentiate and grow. Increases in a phytomer can be measured using the rate of phyllochron (rate of appearance of leaves on a shoot). Related to the phyllochron is the plastochron, which is the rate of leaf primordia initiation. Since many more leaf primordia are initiated than leaves develop, the plastochron develops at a much faster rate (sometimes as much as twice as quickly) as the phyllochron. Initially, a young plant will only produce phytomers at its apical meristems but later in development, secondary meristems will begin to form and phytomers will be formed on this lateral plant growth.

Biology

https://en.wikipedia.org/wiki?curid=19002387

Phytomer

Near-death experience A near-death experience (NDE) is a profound personal experience associated with death or impending death which researchers claim share similar characteristics. When positive, such experiences may encompass a variety of sensations including detachment from the body, feelings of levitation, total serenity, security, warmth, the experience of absolute dissolution, and the presence of a light. When negative, such experiences may include sensations of anguish and distress. Explanations for NDEs vary from scientific to religious. Neuroscience research suggests that an NDE is a subjective phenomenon resulting from "disturbed bodily multisensory integration" that occurs during life-threatening events, while some transcendental and religious beliefs about an afterlife include descriptions similar to NDEs. The equivalent French term "expérience de mort imminente" (experience of imminent death) was proposed by French psychologist and epistemologist Victor Egger as a result of discussions in the 1890s among philosophers and psychologists concerning climbers' stories of the panoramic life review during falls. In 1892 a series of subjective observations by workers falling from scaffolds, war soldiers who suffered injuries, climbers who had fallen from heights or other individuals who had come close to death (near drownings, accidents) was reported by Albert Heim. This was also the first time the phenomenon was described as clinical syndrome

Biology

https://en.wikipedia.org/wiki?curid=19008500

Near-death experience

Near-death experience In 1968 Celia Green published an analysis of 400 first-hand accounts of out-of-body experiences. This represented the first attempt to provide a taxonomy of such experiences, viewed simply as anomalous perceptual experiences, or hallucinations. In 1969, Swiss-American psychiatrist and pioneer in near-death studies Elisabeth Kubler-Ross published her groundbreaking book "On Death and Dying: What the dying have to teach doctors, nurses, clergy, and their own families." These experiences were also popularized by the work of psychiatrist Raymond Moody, who in 1975 coined the term "near-death experience" (NDE) as an umbrella term for the different elements (out of body experiences, the "panoramic life review," the Light, the tunnel, or the border). The term "near-death experience" had already been used by John C. Lilly in 1972. Researchers have identified the common elements that define near-death experiences. Bruce Greyson argues that the general features of the experience include impressions of being outside one's physical body, visions of deceased relatives and religious figures, and transcendence of egotic and spatiotemporal boundaries. Many common elements have been reported, although the person's interpretation of these events often corresponds with the cultural, philosophical, or religious beliefs of the person experiencing it

Biology

https://en.wikipedia.org/wiki?curid=19008500

Near-death experience

Near-death experience For example, in the US, where 46% of the population believes in guardian angels, they will often be identified as angels or deceased loved ones (or will be unidentified), while Hindus will often identify them as messengers of the god of death. Common traits that have been reported by NDErs are as follows: Kenneth Ring (1980) subdivided the NDE on a five-stage continuum. The subdivisions were: Charlotte Martial, a neuropsychologist from the University of Liège and University Hospital of Liège who led a team that investigated 154 NDE cases, concluded that there is not a fixed sequence of events. Kenneth Ring argues that attempted suicides do not lead more often to unpleasant NDEs than unintended near-death situations. NDEs are associated with changes in personality and outlook on life. Ring has identified a consistent set of value and belief changes associated with people who have had a near-death experience. Among these changes, he found a greater appreciation for life, higher self-esteem, greater compassion for others, less concern for acquiring material wealth, a heightened sense of purpose and self-understanding, desire to learn, elevated spirituality, greater ecological sensitivity and planetary concern, and a feeling of being more intuitive. However, not all after-effects are beneficial and Greyson describes circumstances where changes in attitudes and behavior can lead to psychosocial and psychospiritual problems. NDEs have been recorded since ancient times

Biology

https://en.wikipedia.org/wiki?curid=19008500

Near-death experience

Near-death experience The oldest known medical report of near-death experiences was written by Pierre-Jean du Monchaux, an 18th-century French military doctor who described such a case in his book "Anecdotes de Médecine." In the 19th century a few studies moved beyond individual cases - one privately done by the Mormons and one in Switzerland. Up to 2005, 95% of world cultures are known to have made some mention of NDEs. A number of more contemporary sources report the incidence of near death experiences as: Bruce Greyson (psychiatrist), Kenneth Ring (psychologist), and Michael Sabom (cardiologist), helped to launch the field of near-death studies and introduced the study of near-death experiences to the academic setting. From 1975 to 2005, some 2,500 self-reported individuals in the US had been reviewed in retrospective studies of the phenomena with an additional 600 outside the US in the West, and 70 in Asia. Additionally, prospective studies had identified 270 individuals. Prospective studies review groups of individuals (e.g., selected emergency room patients) and then find who had an NDE during the study's time; such studies cost more to perform. In all, close to 3,500 individual cases between 1975 and 2005 had been reviewed in one or another study. All these studies were carried out by some 55 researchers or teams of researchers. Melvin Morse, head of the Institute for the Scientific Study of Consciousness, and colleagues have investigated near-death experiences in a pediatric population

Biology

https://en.wikipedia.org/wiki?curid=19008500

Near-death experience

Near-death experience In 2001, Sam Parnia and colleagues published the results of a year-long study of cardiac arrest survivors that was conducted at Southampton General Hospital. 63 survivors were interviewed. They had been resuscitated after being clinically dead with no pulse, no respiration, and fixed dilated pupils. Parnia and colleagues investigated out-of-body experience claims by placing figures on suspended boards facing the ceiling, not visible from the floor. Four had experiences that, according to the study criteria, were NDEs but none of them experienced the out-of-body experience. Thus, they were not able to identify the figures. Psychologist Chris French wrote regarding the study "unfortunately, and somewhat atypically, none of the survivors in this sample experienced an OBE". In 2001, Pim van Lommel, a cardiologist from the Netherlands, and his team conducted a study on NDEs including 344 cardiac arrest patients who had been successfully resuscitated in 10 Dutch hospitals. Patients not reporting NDEs were used as controls for patients who did, and psychological (e.g., fear before cardiac arrest), demographic (e.g., age, sex), medical (e.g., more than one cardiopulmonary resuscitation (CPR)), and pharmacological data were compared between the two groups. The work also included a longitudinal study where the two groups (those who had had an NDE and those who had not had one) were compared at two and eight years, for life changes. One patient had a conventional out of body experience

Biology

https://en.wikipedia.org/wiki?curid=19008500

Near-death experience

Near-death experience He reported being able to watch and recall events during the time of his cardiac arrest. His claims were confirmed by hospital personnel. "This did not appear consistent with hallucinatory or illusory experiences, as the recollections were compatible with real and verifiable rather than imagined events". While at University of Southampton, Parnia was the principal investigator of the AWARE Study, which was launched in 2008. This study which concluded in 2012 included 33 investigators across 15 medical centers in the UK, Austria and the US and tested consciousness, memories and awareness during cardiac arrest. The accuracy of claims of visual and auditory awareness was examined using specific tests. One such test consisted in installing shelves, bearing a variety of images and facing the ceiling, hence not visible by hospital staff, in rooms where cardiac-arrest patients were more likely to occur. The results of the study were published in October 2014; both the launch and the study results were widely discussed in the media. A review article analyzing the results reports that, out of 2,060 cardiac arrest events, 101 of 140 cardiac arrest survivors could complete the questionnaires. Of these 101 patients 9% could be classified as near death experiences. Two more patients (2% of those completing the questionnaires) described "seeing and hearing actual events related to the period of cardiac arrest"

Biology

https://en.wikipedia.org/wiki?curid=19008500

Near-death experience

Near-death experience These two patients' cardiac arrests did not occur in areas equipped with ceiling shelves hence no images could be used to objectively test for visual awareness claims. One of the two patients was too sick and the accuracy of her recount could not be verified. For the second patient, however, it was possible to verify the accuracy of the experience and to show that awareness occurred paradoxically some minutes after the heart stopped, at a time when "the brain ordinarily stops functioning and cortical activity becomes isoelectric." The experience was not compatible with an illusion, imaginary event or hallucination since visual (other than of ceiling shelves' images) and auditory awareness could be corroborated. , a posting at the UK Clinical Trials Gateway website described plans for AWARE II, a two-year multicenter observational study of 900-1500 patients experiencing cardiac arrest, which said that subject recruitment had started on 1 August 2014 and that the scheduled end date was 31 May 2017. The study was extended, and it is currently expected to end in 2020. A three-year longitudinal study has revealed that some Buddhist meditation practitioners are able to willfully induce near-death experiences at a pre-planned point in time. Unlike traditional NDEs, participants were consciously aware of experiencing the meditation-induced NDE and retained control over its content and duration

Biology

https://en.wikipedia.org/wiki?curid=19008500

Near-death experience

Near-death experience The Dalai Lama has also asserted that experienced meditators can deliberately induce the NDE state during meditation, being able to recognize and sustain it. In a review article, psychologist Chris French has grouped approaches to explain NDEs in three broad groups which "are not distinct and independent, but instead show considerable overlap": spiritual theories (also called transcendental), psychological theories, and physiological theories that provide a physical explanation for NDEs. French summarizes this model by saying : "the most popular interpretation is that the NDE is exactly what it appears to be to the person having the experience". The NDE would then represent evidence of the supposedly immaterial existence of a soul or mind, which would leave the body upon death. An NDE would then provide information about an immaterial world where the soul would journey upon ending its physical existence on earth. According to Greyson some NDE phenomena cannot be easily explained with our current knowledge of human physiology and psychology. For instance, at a time when they were unconscious patients could accurately describe events as well as report being able to view their bodies "from an out-of-body spatial perspective". In two different studies of patients who had survived a cardiac arrest, those who had reported leaving their bodies could describe accurately their resuscitation procedures or unexpected events, whereas others "described incorrect equipment and procedures"

Biology

https://en.wikipedia.org/wiki?curid=19008500

Near-death experience

Near-death experience Sam Parnia also refers to two cardiac arrest studies and one deep hypothermic circulatory arrest study where patients reported visual and/or auditory awareness occurring when their brain function had ceased. These reports "were corroborated with actual and real events". Five prospective studies have been carried out, to test the accuracy of out of body perceptions by placing "unusual targets in locations likely to be seen by persons having NDEs, such as in an upper corner of a room in the emergency department, the coronary care unit, or the intensive care unit of a hospital." Twelve patients reported leaving their bodies, but none could describe the hidden visual targets. Although this is a small sample, the failure of purported out-of-body experiencers to describe the hidden targets raises questions about the accuracy of the anecdotal reports described above. One of the researchers that have conducted this kind of hidden targets explains why the targets were not seen by the patients: Psychologist James Alcock has described the afterlife claims of NDE researchers as pseudoscientific. Alcock has written the spiritual or transcendental interpretation "is based on belief in search of data rather than observation in search of explanation." Chris French has noted that "the survivalist approach does not appear to generate clear and testable hypotheses

Biology

https://en.wikipedia.org/wiki?curid=19008500

Near-death experience

Near-death experience Because of the vagueness and imprecision of the survivalist account, it can be made to explain any possible set of findings and is therefore unfalsifiable and unscientific." The medical researcher Penny Sartori has observed that people close to the time of death start to see dead people and can communicate with them. This is a very common fact and known to the nursing body. She tells the story of a patient who saw three deceased relatives, two of whom he knew were dead but one had passed away only a week before the event and the patient was not yet aware of it. French summarises the main psychological explanations which include: the depersonalization, the expectancy and the dissociation models. A depersonalization model was proposed in the 1970s by professor of psychiatry Russell Noyes and clinical psychologist Roy Kletti, which suggested that the NDE is a form of depersonalization experienced under emotional conditions such as life-threatening danger, potentially inescapable danger, and that the NDE can best be understood as an hallucination. According to this model, those who face their impending death become detached from the surroundings and their own bodies, no longer feel emotions, and experience time distortions. This model suffers from a number of limitations to explain NDEs for subjects who do not experience a sensation of being out of their bodies; unlike NDEs, experiences are dreamlike, unpleasant and characterized by "anxiety, panic and emptiness"

Biology

https://en.wikipedia.org/wiki?curid=19008500

Near-death experience

Near-death experience Also, during NDEs subjects remain very lucid of their identities, their sense of identity is not changed unlike those experiencing depersonalization. Another psychological theory is called the expectancy model. It has been suggested that although these experiences could appear very real, they had actually been constructed in the mind, either consciously or subconsciously, in response to the stress of an encounter with death (or perceived encounter with death), and did not correspond to a real event. In a way, they are similar to wish-fulfillment: because someone thought they were about to die, they experienced certain things in accordance with what they expected or wanted to occur. Imagining a heavenly place was in effect a way for them to soothe themselves through the stress of knowing that they were close to death. Subjects use their own personal and cultural expectations to imagine a scenario that would protect them against an imminent threat to their lives. Subjects' accounts often differed from their own "religious and personal expectations regarding death" which contradicts the hypothesis they may have imagined a scenario based on their cultural and personal background. Although the term NDE was first coined in 1975 and the experience first described then, recent descriptions of NDEs do not differ from those reported earlier than 1975. The only exception is the more frequent description of a tunnel

Biology

https://en.wikipedia.org/wiki?curid=19008500

Near-death experience

Near-death experience Hence, the fact that information about these experiences could be more easily obtained after 1975, did not influence people's reports of the experiences. Another flaw of this model can be found in children's accounts of NDEs. These are similar to adults', and this despite children being less affected by religious or cultural influences about death. The dissociation model proposes that NDE is a form of withdrawal to protect an individual from a stressful event. Under extreme circumstances some people may detach from certain unwanted feelings in order to avoid experiencing their emotional impact and suffering associated with them. The person also detaches from one's immediate surroundings. The birth model suggests that near death experiences could be a form of reliving the trauma of birth. Since a baby travels from the darkness of the womb to light and is greeted by the love and warmth of the nursing and medical staff, and so, it was proposed, the dying brain could be recreating the passage through a tunnel to light, warmth and affection. Reports of leaving the body through a tunnel are equally frequent among subjects who were born by cesarean section and natural birth. Also, newborns do not possess "the visual acuity, spatial stability of their visual images, mental alertness, and cortical coding capacity to register memories of the birth experience"

Biology

https://en.wikipedia.org/wiki?curid=19008500

Near-death experience

Near-death experience A wide range of physiological theories of the NDE have been put forward including those based upon cerebral hypoxia, anoxia, and hypercapnia; endorphins and other neurotransmitters; and abnormal activity in the temporal lobes. Neurobiological factors in the experience have been investigated by researchers in the field of medical science and psychiatry. Among the researchers and commentators who tend to emphasize a naturalistic and neurological base for the experience are the British psychologist Susan Blackmore (1993), with her "dying brain hypothesis". Neuroscientists Olaf Blanke and Sebastian Dieguez (2009), from the "Ecole Polytechnique Fédérale de Lausanne", Switzerland, propose a brain based model with two types of NDEs : They suggest that damage to the bilateral occipital cortex may lead to visual features of NDEs such as seeing a tunnel or lights, and "damage to unilateral or bilateral temporal lobe structures such as the hippocampus and amygdala" may lead to emotional experiences, memory flashbacks or a life review. They concluded that future neuroscientific studies are likely to reveal the neuroanatomical basis of the NDE which will lead to the demystification of the subject without needing paranormal explanations. French has written that the "temporal lobe is almost certain to be involved in NDEs, given that both damage to and direct cortical stimulation of this area are known to produce a number of experiences corresponding to those of the NDE, including OBEs, hallucinations, and memory flashbacks"

Biology

https://en.wikipedia.org/wiki?curid=19008500

Near-death experience

Near-death experience Vanhaudenhuyse "et al". 2009 reported that recent studies employing deep brain stimulation and neuroimaging have demonstrated that out-of-body experiences result from a deficient multisensory integration at the temporoparietal junction and that ongoing studies aim to further identify the functional neuroanatomy of near-death experiences by means of standardized EEG recordings. According to Greyson multiple neuroanatomical models have been proposed where NDEs have been hypothesized to originate from different anatomical areas of the brain, namely: the limbic system, the hippocampus, the left temporal lobe, Reissen's fiber in the central canal of the spinal cord, the prefrontal cortex, the right temporal lobe. Blanke et al. admit that their model remains speculative to the lack of data. Likewise Greyson writes that although some or any of the neuroanatomical models proposed may serve to explain NDEs and pathways through which they are expressed, they remain speculative at this stage since they have not been tested in empirical studies. Some theories hypothesize that drugs used during resuscitation induced NDEs, for example, ketamine or as resulting from endogeneous chemicals that transmit signals between brain cells, neurotransmitters: According to Parnia, neurochemical models are not backed by data. This is true for "NMDA receptor activation, serotonin, and endorphin release" models

Biology

https://en.wikipedia.org/wiki?curid=19008500

Near-death experience

Near-death experience Parnia writes that no data has been collected via thorough and careful experimentation to back "a possible causal relationship or even an association" between neurochemical agents and NDE experiences. The first formal neurobiological model for NDE, included endorphins, neurotransmitters of the limbic system, the temporal lobe and other parts of the brain. Extensions and variations of their model came from other scientists such as Louis Appleby (1989). Other authors suggest that all components of near-death experiences can be explained in their entirety via psychological or neurophysiological mechanisms, although the authors admit that these hypotheses have to be tested by science. Low oxygen levels in the blood (hypoxia or anoxia) have been hypothesized to induce hallucinations and hence possibly explain NDEs. This is because low oxygen levels characterize life-threatening situations and also by the apparent similarities between NDEs and G-force induced loss of consciousness (G-LOC) episodes. These episodes are observed with fighter pilots experiencing very rapid and intense acceleration that result in lack of sufficient blood supply to the brain

Biology

https://en.wikipedia.org/wiki?curid=19008500

Near-death experience

Near-death experience Whinnery studied almost 1000 cases and noted how the experiences often involved "tunnel vision and bright lights, floating sensations, automatic movement, autoscopy, OBEs, not wanting to be disturbed, paralysis, vivid dreamlets of beautiful places, pleasurable sensations, psychological alterations of euphoria and dissociation, inclusion of friends and family, inclusion of prior memories and thoughts, the experience being very memorable (when it can be remembered), confabulation, and a strong urge to understand the experience." However, hypoxia-induced acceleration's primary characteristics are "rythmic jerking of the limbs, compromised memory of events just prior to the onset of unconsciousness, tingling of extremities ..." that are not observed during NDEs. Also G-LOC episodes do not feature life reviews, mystical experiences and "long-lasting transformational aftereffects", although this may be due to the fact that subjects have no expectation of dying. Also, hypoxic hallucinations are characterized by "distress and agitation" and this is very different from near death experiences which subjects report as being pleasant. Some investigators have studied whether hypercarbia or higher than normal carbon dioxide levels, could explain the occurrence of NDEs. However, studies are difficult to interpret since NDEs have been observed both with increased levels as well as decreased levels of carbon dioxide, and finally some other studies have observed NDEs when levels had not changed, and there is little data

Biology

https://en.wikipedia.org/wiki?curid=19008500

Near-death experience

Near-death experience French said that at least some reports of NDEs might be based upon false memories. According to Engmann (2008) near-death experiences of people who are clinically dead are psychopathological symptoms caused by a severe malfunction of the brain resulting from the cessation of cerebral blood circulation. An important question is whether it is possible to "translate" the bloomy experiences of the reanimated survivors into psychopathologically basic phenomena, e.g., acoasms (nonverbal auditory hallucinations), central narrowing of the visual field, autoscopia, visual hallucinations, activation of limbic and memory structures according to Moody's stages. The symptoms suppose a primary affliction of the occipital and temporal cortices under clinical death. This basis could be congruent with the thesis of pathoclisis—the inclination of special parts of the brain to be the first to be damaged in case of disease, lack of oxygen, or malnutrition—established eighty years ago by Cécile and Oskar Vogt. Professor of neurology Terence Hines (2003) claimed that near-death experiences are hallucinations caused by cerebral anoxia, drugs, or brain damage. Gregory Shushan published an analysis of the afterlife beliefs of five ancient civilisations (Old and Middle Kingdom Egypt, Sumerian and Old Babylonian Mesopotamia, Vedic India, pre-Buddhist China, and pre-Columbian Mesoamerica) and compared them with historical and contemporary reports of near-death experiences, and shamanic afterlife "journeys"

Biology

https://en.wikipedia.org/wiki?curid=19008500

Near-death experience

Near-death experience Shushan found similarities across time, place, and culture that he found could not be explained by coincidence; he also found elements that were specific to cultures; Shushan concludes that some form of mutual influence between experiences of an afterlife and culture probably influence one another and that this inheritance in turn influences individual NDEs. In contrast, it has been argued that near-death experiences and many of their elements (vision of God, judgment, the tunnel, or the life review) are closely related to religious and spiritual traditions of the West. It was mainly Christian visionaries, Spiritualists, Occultists, and Theosophists of the 19th and 20th century that reported them (Schlieter 2018). According to Parnia, near death experiences' interpretations are influenced by religious, social, cultural backgrounds. However, the core elements appear to transcend borders and can be considered universal. In fact, some of these core elements have even been reported by children <3 years old (this occurred over many months, whilst playing and communicated using children's language). In other words, at an age where they should not have been influenced by culture or tradition. Also, according to Greyson, the central features of NDEs are universal and have not been influenced by time. These have been observed throughout history and in different cultures.

Biology

https://en.wikipedia.org/wiki?curid=19008500

Near-death experience

Médaille de la Famille française The () is a decoration awarded by the government of France to honour those who have successfully raised several children with dignity. The decoration was created by a decree of May 26, 1920, under the name Médaille d'honneur de la famille française, with the aim of honouring mothers of large families. Although the medal rewards those with large families, the children must be "raised well" and the eldest be at least 16 years old. The decoration was created by a decree of May 26, 1920, under the name Médaille d'honneur de la famille française ("Medal of Honour of the French Family") with the aim of honouring mothers of large families. The text of the decree underwent several changes before being completely reformed by a decree of October 28, 1982, which renamed the decoration ("Medal of the French Family"). This decree came into force on January 1, 1983, and was completed by an "arrêté" (administrative order) of March 15, 1983. The reform opened the award of the decoration to fathers and others who had raised several children in an appropriate way: for example, the Catholic priest Père Mayotte, curate of the parish of Randan, Puy-de-Dôme was granted the award in recognition of his raising the six children of his housekeeper, a widow who died suddenly. Three classes of medal exist: bronze for those raising four or five children, silver for parents of six or seven children, and gold for those with eight or more children

Biology

https://en.wikipedia.org/wiki?curid=19026713

Médaille de la Famille française

Médaille de la Famille française A bronze medal is also granted to widowed mothers of three children whose husbands have been killed in action. The recipient's eldest child must be at least sixteen years old. The original medal was an eight pointed radiant star, with a central medallion depicting a mother holding a small child, surrounded by the inscription "Famille Française", ("French Family"). Since 1983 a circular medal has been awarded, bearing the words "Famille Française" above a modernistic image of a couple and their children. The words "République Française" ("French Republic") are inscribed on the reverse side. The ribbon of both versions is the same, and has three equal parts, the outer two being red and the inner green. Recipients of silver and gold medals are also granted a rosette in the same colours. Recommendations or applications for the award must be deposited at the local town hall. An enquiry into the family is then conducted. If the enquiry reports positively, the final decision on whether to grant the award belongs to the prefect of the department. While the award has always been open to mothers raising families alone, and to other single parents and legal guardians since the 1982 reforms, this applies only in cases of widowhood or abandonment: the medal is only granted to divorced parents in the most exceptional circumstances. The medal may be awarded posthumously, provided that the application is made within two years of the recipient's death.

Biology

https://en.wikipedia.org/wiki?curid=19026713

Médaille de la Famille française

Raised bog Raised bogs, also called ombrotrophic bogs, are acidic, wet habitats that are poor in mineral salts and are home to flora and fauna that can cope with such extreme conditions. Raised bogs, unlike fens, are exclusively fed by precipitation (ombrotrophy) and from mineral salts introduced from the air. They thus represent a special type of bog, hydrologically, ecologically and in terms of their development history, in which the growth of peat mosses over centuries or millennia plays a decisive role. They also differ in character from blanket bogs which are much thinner and occur in wetter, cloudier climatic zones. Raised bogs are very threatened by peat cutting and pollution by mineral salts from the surrounding land (due to agriculture and industry). There are hardly any raised bogs today that are still living and growing. The last great raised bog regions are found in western Siberia and Canada. The term raised bog derives from the fact that this type of bog rises in height over time as a result of peat formation. They are like sponges of peat moss, full of water, that form a more or less dome shape in the landscape. In Germany, the term "Hochmoor" ("high bog"), strictly refers only to the classical, lens-shaped bogs of northwest Germany. The bogs are not influenced by mineral-rich groundwater or surface water, but are fed exclusively by precipitation — mainly rainwater, hence their alternative German designation of "Regenmoor" or "rain-fed bog"

Biology

https://en.wikipedia.org/wiki?curid=19029446

Raised bog

Raised bog Thus the latter refers to all bogs, not just those that are arched or only slightly arched, but which nevertheless are characterized by an extreme mineral salt deficiency and other resulting ecological properties. A living raised bog needs a moist, balanced climate in which to grow. The quantity of precipitation has to be greater than the water losses through discharge and evaporation. In addition, the precipitation must be evenly spread through the year. Raised bogs in Europe have been developing for about 11,000 years, since the beginning of the Holocene and after the retreat of the last ice sheet. As far as their origins are concerned, a distinction is made between lake mires or 'siltation-formed raised bogs' ("Verlandungshochmoore") and 'mire-formed raised bogs' ("wurzelechte Hochmoore"). The former emerged in a secondary process after the silting up of lakes or oxbows (see illustration on the right in the sequence). At first, fens emerged under the influence of groundwater (minerotrophy). Oxygen deficiencies and high acidity in the constantly moist substrate inhibited the decomposition of dead plant parts and led to peat formation. Thus the raised bog rises very slowly above the groundwater level, hence its name. As the resulting peat slowly rises above the influence of mineral salts in the groundwater, it reaches a point where the development of the raised bog begins to change in nature; that is, the bog now becomes fed solely by rainwater, which is low in salt

Biology

https://en.wikipedia.org/wiki?curid=19029446

Raised bog

Raised bog By contrast, mire-formed raised bogs are created directly on the mineral substrate of low-salt areas without having been initially formed as fens (see figure on the left in the sequence). They are formed either as a primary bog due to the erosion of previously dry mineral soils, for example due to clearing, climate change or infiltration, or as a secondary process as a result of the growth of a raised bog on neighbouring mineral soil. The formation of a typical raised bog is a very slow process, which lasts from centuries to a thousand years even in favourable, undisturbed conditions. Furthermore, there are a number of transitional and intermediate bogs, which in different ways combine characteristics of both raised bogs and fens. (See bog.) The main constituents of the peat are rootless peat mosses that grow slowly in height whilst at the same time the lower layer becomes peat as the air is excluded. Depending on the geographical location, various species of peat moss are involved in making a raised bog. The growth rate of the peat layer is only about a millimetre per year. Growing bogs can be divided into two layers. The 'acrotelm' (Greek: "akros" = highest; "telma" = bog) is the upper part and includes the vegetation layer and the bog 'floor'. Here fresh organic substances (peat formation horizon) are created by the growth and dying of plant elements. The "catotelm" (Greek: kato = below) is the underlying water-saturated part with less biological activity

Biology

https://en.wikipedia.org/wiki?curid=19029446

Raised bog

Raised bog This layer is counted as a geological subsoil due to the small earth-forming processes that are still going on and is known as the peat preservation horizon ("Torferhaltungshorizont"). In raised bogs, the upper peat layer is called white peat, since it consists of largely undecomposed light brown peat mosses. The lower layer is black peat, which is already well humified and has a black-brown colour with still recognizable plant remains. The formation of raised bogs is dependent on the climate, that is to say the amount of precipitation and rate of evaporation, which in turn are decisively determined by the temperature. In addition, the relief of the terrain has an influence on the water discharge behaviour and thus the shape of a raised bog. This results in geographical limitations to the formation of raised bogs. Favourable conditions for the development of raised bogs are found mainly in North America (Canada and Alaska), Northern Europe and Western Siberia, South America, Southeast Asia and in the Amazon Basin. In these regions, bogs of all kinds and peat deposits of four million square kilometres have been formed, covering three percent of the earth's surface. In the southern hemisphere low-mineral-rich bogs are rarely formed from peat mosses. Only in the Tierra del Fuego do peat moss raised bogs exist. The most peaty countries in the tropics are found in Southeast Asia. In many cases it is not yet clear how these bogs have emerged as mosses are entirely absent here

Biology

https://en.wikipedia.org/wiki?curid=19029446

Raised bog

Raised bog Coastal bogs ("Planregenmoore") or Atlantic bogs, as their names suggest, tend to form close to the sea. In addition, in regions covered by blanket bog, there are also lightly convex coastal bogs with low energy surface relief in level locations. The distribution of coastal bogs in Europe extends from Ireland to the east via South Norway to Southwest Sweden and north to the Lofoten. In North America there are coastal bogs in the area of the Great Lakes (especially in Minnesota and Ontario). Coastal bogs are also fed exclusively by rain. In the less oceanically influenced climatic regions of North-West Europe (lower precipitation), raised bogs take on the classical lens shape and are called plateau bogs or plateau raised bogs ("Plateauregenmoore"). They grow more strongly in the centre than at the margins. This results in the centre of the bog bulging, hence the name "raised bog". This bulging can be several metres high. As a result, the perimeter of the bog is more or less inclined, and is known as the "rand". The sloping bog sides of larger bogs are traversed by drainage channels or soaks ("Rüllen") through which excess water is discharged. Other characteristic structures of these raised bogs are the flat, treeless raised bog core with its characteristic microrelief of shallow wet depressions or flarks ("Schlenken") alternating with hummocks ("Bülten") of drier peat moss

Biology

https://en.wikipedia.org/wiki?curid=19029446

Raised bog

Raised bog Larger accumulations of water in the middle of the bogs are called kolks or bog ponds (of humic acid-rich water); the wet area on the outer margins is known as a moat or "lagg". Genuine ombrotrophic bogs on the North German Plain are usually sharply divided into two layers: an underlying black peat layer, which is strongly decomposed, and an overlying white peat layer which is less decomposed. This difference is a result of changes in the hydrology of the bog. The white peat grew more rapidly under humid conditions than the black peat. This is attributed to a climate change with high precipitation and low evaporation around 1000 to 500 BC. As a result, the peat moss growth grew locally and the black peat/white peat boundary layer was formed, although this did not develop simultaneously in all raised bogs. Raised bogs also occur in precipitation-rich upland regions at the montane and, more rarely, alpine levels (i.e. above the tree line). As a result of the sloping terrain, they often have a characteristic, asymmetric or non-concentric appearance. Mountain or upland bogs may be topographically divided into: All these bog types may occur on the margins of lowland bogs i.e. fens, or transition into them. Kermi bogs ("Kermimoore, Schildhochmoore, Strangmoore" or "Blankenmoore") or kermi raised bogs have only a slightly domed shape. The surface of the bog rises steadily from the broad lagg zone. Kermis have ridge-shaped hummocks of peat moss, that are aligned with the contours of the bog

Biology

https://en.wikipedia.org/wiki?curid=19029446

Raised bog

Raised bog The flarks or elongated depressions are generally tub-shaped and hardly distinguishable externally from kolks. In the central area of these bogs, there are always large kolks. In northern Russia and western Sibiria, kermis frequently occur in giant complexes where the bogs have grown into one another. Kermis are also found in Finland in the central and northern boreal forest zone. String bogs or aapa fens ("Aapamoore" or "Strangmoore") are typically found on the northern fringes of the distribution area for raised bogs, in the sub-polar zone, north of the 66th latitude in the northern hemisphere. Here, raised bogs only occur as islands within wetlands supplied by mineral soil water. On level ground these islands are irregularly distributed; on hillsides they form ridges parallel to the contours and at right angles to line of slope. The ridges separate boggy hollows of mineral soil known by the Finnish word, "rimpis". The main distribution area for string bogs are the Scandinavian hills, central Finland, Karelia and north Sibiria. In North America, Alaska is the main location for string bogs, thanks to its cold continental climate. Frost action plays an important role in these bogs. On the ridges or hummocks, ground ice is found until early summer. Palsa bogs ("Palsamoore" or "Palsenmoore") are found on the margins of the Arctic permafrost soils (tundra). Here the ridges of the string bogs can grow into hummocks several metres high

Biology

https://en.wikipedia.org/wiki?curid=19029446

Raised bog

Raised bog Like string bogs, the so-called palsas frequently lie within peatlands fed by mineral soil water. Some are surrounded by water-filled, ditch-like hollows. Peat formation is limited; these bogs are peat deposits from warmer, interglacial periods and did not experience frost heaving of their inner core of ice until the climate became colder. These ice lenses increase in size from year to year as a result of freeze-thaw processes of the surrounding water. The low temperatures prevent full decomposition of the organic material. Polygonal bogs ("Polygonmoore") are widespread on the Arctic and sub-Arctic plains of Sibiria and North Americas and cover vast areas. They are associated with patterned peatland and ice wedges. A scanty layer of peat-forming vegetation can occur in the inner honeycomb-shaped areas of this frost pattern terrain (cryoturbation) and are fed during the short summers with sufficient moisture, because the meltwater is prevented from draining away by the raised polygonal margins. The peat layers can attain a thickness of . The west Siberian raised bog area covers . The large bogs have domes in the centre up to high. They are predominantly of the kermi bog type. They represent probably the most important type of raised bog on earth. The Vasyugan Swamp in this region, is the largest bog system on earth and covers more than . It is estimated to contain over 14 billion tonnes of peat deposits

Biology

https://en.wikipedia.org/wiki?curid=19029446

Raised bog

Raised bog The largest central European raised bog areas are the southern North Sea coastal area and the Alpine Foreland. As in North America there is a succession of raised bog types along the line of descent towards the ocean, from northwest to southeast. As a result of peat use, raised bogs have been harvested for peat and cultivated, apart from a few remnants (less than 10% of the original area). The largest contiguous raised bog in central Europe was the Bourtange Moor, which originally covered an area of about 2,300 km² including the Dutch portion, but only small sections remain. The largest remaining raised bog in northern Europe is the 76 km² Lille Vildmose. Other large raised bogs are the Teufelsmoor northeast of Bremen, the Vehnemoor (exhausted) and the Esterweger Dose (formerly about 80 km², exhausted) between Oldenburg and Papenburg. The raised bogs of the Central Uplands of the Harz, Solling, Thuringian Forest (Großer Beerberg, Schneekopf - Teufelsbad, Fichtenkopf, Saukopf), Giant Mountains, Ore Mountains, Fichtel and Rhön (Black Moor, Red Moor) are, by contrast, comparatively small. In the Black Forest the Wildseemoor has been protected and, in the Vosges on "le Tanet", north of the Col de la Schlucht a large area has been protected. The Alpine Foreland, which was formed by ice-age glaciation, is also rich in peatland. The Wurzacher Ried (Haidgauer Regenmoorschild) is considered the largest and best preserved raised bog in central Europe

Biology

https://en.wikipedia.org/wiki?curid=19029446

Raised bog

Raised bog Other raised bogs and peatland areas include the Federsee, the High Fens on the Germano-Belgian border, the Ewiges Meer near Aurich and the Lengener Meer near Wiesmoor. In 2003, Estonia exported 3.6 million m³ of peat for west European garden use, more than 60% of the state production. In Lithuania 60% of the usable peat area has been prepared for extraction or is already exhausted. Lough Lurgeen Bog and Glenamaddy Turlough Bog contains very good examples of the Annex 1 habitats: active raised bog, turlough (both priority habitats), degraded raised bog (capable of regeneration) and vegetation of depressions (rhynchosporion). These habitats are considered to be among the best examples in Ireland due to their relatively large size and the generally low levels of disturbance. In the Natura form compiled for the site active raised bog was given a rating of A (Excellent value) which emphasises the importance of the site. habitats are now very rare in Europe and it has recently been estimated that the Republic of Ireland contains 50% of the relatively intact oceanic raised bog systems in Europe. The site contains the second largest area of intact raised bog surface in Ireland. The combination of raised bog, oligotrophic lake and turlough habitats is unique in Ireland and thus the entire system is very important from both a hydrological and ecological perspective. A region of peatland extends from Alaska in the west to the coast of the Atlantic in the east, and is comparable in size to that of West Siberia

Biology

https://en.wikipedia.org/wiki?curid=19029446

Raised bog

Raised bog A zone of domed raised bogs adjoins the zones of palsa bogs and string fens. In the direction of descent towards the ocean, blanket bogs occur east of Hudson Bay. These are superseded towards the west by plateau bogs in the area of the large lakes and, eventually, by kermi bogs.

Biology

https://en.wikipedia.org/wiki?curid=19029446

Raised bog

Allelic heterogeneity is the phenomenon in which different mutations at the same locus lead to the same or very similar phenotypes. These allelic variations can arise as a result of natural selection processes, as a result of exogenous mutagens, genetic drift, or genetic migration. Many of these mutations take the form of single nucleotide polymorphisms in which a single nucleotide base is altered compared to a consensus sequence. They can also exist as copy number variants (CNV) in which the copies of a gene or DNA sequence is different from the population. Mutated alleles expressing allelic heterogeneity can be classified as adaptive or disadaptive. These mutations can occur in the germ line cells, somatic cells, or in the mitochondrial. Mutations in germ line cells can be inherited as well as mitochondrial allelic mutations. The mitochondrial allelic mutations are inherited maternally. Typically in the human genome a small amount of allele variants account for ~75% of the mutations found at a particular locus within a population. Other variants found are considered to be rare or exclusive to a single pedigree. The Online Mendelian Inheritance of Man has a record of over 1000 genes and their associated allelic variants. These genes display allelic heterogeneity at their loci and are responsible for distinct disease phenotypes. Some of these diseases include alkaptonuria, albinism, achondroplasia, and phenylketonuria. For example, β-thalassemia may be caused by several different mutations in the β-globin gene

Biology

https://en.wikipedia.org/wiki?curid=19031099

Allelic heterogeneity

Allelic heterogeneity should not be confused with locus heterogeneity in which a mutation at a different gene causes a similar phenotype. Nor should it be confused with phenotypic heterogeneity in which a mutation within the same gene causes a different phenotype. Other major diseases displaying allelic heterogeneity are allelic mutations in the dystrophin gene which cause Duchenne dystrophy and mutations in the CFTR gene that are known to causes cystic fibrosis. The human gene for the HGD nucleotide sequence shows a number of AKU-causing allelic mutations. Approximately 40 different allelic variants have been documented. Most of these variants do not have an effect on the enzyme catalysis function. A few known alleles have an indirect effect on protein function by causing misfolding and disrupt the proper assembly of the enzyme complex. Alkaptunoria is considered to be a classic example of allelic heterogeneity showing a single variant in the human phenotype.

Biology

https://en.wikipedia.org/wiki?curid=19031099

Allelic heterogeneity

IHS Markit Ltd is a London–based global information provider formed in 2016 with the merger of IHS Inc. and Markit Ltd. Some parts of this company are pre-1800. One part of this conglomerate originally was a firm that assigns IMO identification numbers for ships, companies and registered owners. It has since grown to incorporate other companies in the information services sector, many dating back to the late 1700s and 1800s. These include Cambridge Energy Research Associates, Global Insight, Jane's Information Group, Carfax, Inc., Prime Publications Limited, and John S. Herold, Inc. In 2016 Englewood, Colorado–based IHS and London-based Markit merged. Information Handling Services (IHS) "was founded in 1959 as Information Handling Services to provide information for aerospace engineers through microfilm databases." Jerre Stead was the chief executive from 2006 to 2013 and from 2015 until the merger with Markit. Markit was founded in 2003 as Mark-it Partners, a financial data provider for daily credit default swap pricing. The company grew via joint ventures and by acquiring other companies, merging with IHS in 2016. IHS's founding date refers to a 1959-initiated publication about microfilm begun by an Englewood, Colorado-based former RELX- precursor which Norman L. Cahners' 1945-initiated publishing empire, led by Modern Materials Handling acquired and expanded.

Biology

https://en.wikipedia.org/wiki?curid=19035615

IHS Markit

Living Human Project The (LHP) is a project that begun in 2002 to develop a distributed repository of anatomo-functional data and simulation algorithms for the human musculoskeletal apparatus used to create the physiome of the human musculoskeletal system. In 2006 the BEL was merged with Biomed Town, an Internet community for those who have a professional interest in biomedical research. The LHDL project was ended in January 2009, and soon after the LHDL consortium released a biomedical data management and sharing service called "Physiome Space". Physiome Space lets individual researchers as well as for large consortia to share with their peers large collections of biomedical data, including medical imaging and computer simulations.

Biology

https://en.wikipedia.org/wiki?curid=19041370

Living Human Project

Dark fermentation is the fermentative conversion of organic substrate to biohydrogen. It is a complex process manifested by diverse groups of bacteria, involving a series of biochemical reactions using three steps similar to anaerobic conversion. differs from photofermentation in that it proceeds without the presence of light. Fermentative/hydrolytic microorganisms hydrolyze complex organic polymers to monomers which are further converted to a mixture of lower-molecular-weight organic acids and alcohols by obligatory producing acidogenic bacteria. Utilization of wastewater as a potential substrate for biohydrogen production has been drawing considerable interest in recent years especially in the dark fermentation process. Industrial wastewater as a fermentative substrate for H production addresses most of the criteria required for substrate selection viz., availability, cost and biodegradability (Angenent, "et al.", 2004; Kapdan and Kargi, 2006). Chemical wastewater (Venkata Mohan, "et al.", 2007a,b), cattle wastewater (Tang, "et al.", 2008), dairy process wastewater (Venkata Mohan, "et al." 2007c, Rai et al. 2012), starch hydrolysate wastewater (Chen, "et al.", 2008) and designed synthetic wastewater (Venkata Mohan, "et al.", 2007a, 2008b) have been reported to produce biohydrogen apart from wastewater treatment from dark fermentation processes using selectively enriched mixed cultures under acidophilic conditions. Various wastewaters viz., paper mill wastewater (Idania, "et al.", 2005), starch effluent (Zhang, "et al

Biology

https://en.wikipedia.org/wiki?curid=19042247

Dark fermentation

Dark fermentation ", 2003), food processing wastewater (Shin "et al.", 2004, van Ginkel, "et al.", 2005), domestic wastewater (Shin, "et al.", 2004, 2008e), rice winery wastewater (Yu "et al.", 2002), distillery and molasses based wastewater (Ren, "et al.", 2007, Venkata Mohan, "et al.", 2008a), wheat straw wastes (Fan, "et al.", 2006) and palm oil mill wastewater (Vijayaraghavan and Ahmed, 2006) have been studied as fermentable substrates for H production along with wastewater treatment. Using wastewater as a fermentable substrate facilitates both wastewater treatment apart from H production. The efficiency of the dark fermentative H production process was found to depend on pre-treatment of the mixed consortia used as a biocatalyst, operating pH, and organic loading rate apart from wastewater characteristics (Venkata Mohan, "et al.", 2007d, 2008c, d, Vijaya Bhaskar, "et al.", 2008d). In spite of its advantages, the main challenge observed with fermentative H production processes is the relatively low energy conversion efficiency from the organic source. Typical H yields range from 1 to 2 mol of H/mol of glucose, which results in 80-90% of the initial COD remaining in the wastewater in the form of various volatile organic acids (VFAs) and solvents, such as acetic acid, propionic acid, butyric acid, and ethanol. Even under optimal conditions about 60-70% of the original organic matter remains in solution

Biology

https://en.wikipedia.org/wiki?curid=19042247

Dark fermentation

Dark fermentation Bioaugmentation with selectively enriched acidogenic consortia to enhance H production was also reported (Venkata Mohan, "et al.", 2007b). Generation and accumulation of soluble acid metabolites causes a sharp drop in the system pH and inhibits the H production process. Usage of unutilized carbon sources present in acidogenic process for additional biogas production sustains the practical applicability of the process. One way to utilize/recover the remaining organic matter in a usable form is to produce additional H by terminal integration of photo-fermentative processes of H production (Venkata Mohan, "et al." 2008e, Rai et al. 2012) and methane by integrating acidogenic processes to terminal methanogenic processes.

Biology

https://en.wikipedia.org/wiki?curid=19042247

Dark fermentation

Photofermentation is the fermentative conversion of organic substrate to biohydrogen manifested by a diverse group of photosynthetic bacteria by a series of biochemical reactions involving three steps similar to anaerobic conversion. differs from dark fermentation because it only proceeds in the presence of light. For example, photo-fermentation with "Rhodobacter sphaeroides" SH2C (or many other purple non-sulfur bacteria) can be employed to convert small molecular fatty acids into hydrogen and other products. Phototropic bacteria produce hydrogen gas via photofermentation, where the hydrogen is sourced from organic compounds. <chem>C6H12O6 + 6H2O ->[{hv}] 6CO2 + 12H2</chem> Photolytic producers are similar to phototrophs, but source hydrogen from water molecules that are broken down as the organism interacts with light. Photolytic producers consist of algae and certain photosynthetic bacteria. <chem>12H2O ->[{hv}] 12H2 + 6O2</chem>(algae) <chem>CO + H2O ->[{hv}] H2 + CO2</chem>(photolytic bacteria) via purple nonsulfur producing bacteria has been explored as a method for the production of biofuel. The natural fermentation product of these bacteria, hydrogen gas, can be harnessed as a natural gas energy source. via algae instead of bacteria is used for bioethanol production, among other liquid fuel alternatives. The bacteria and their energy source are held in a bioreactor chamber that is impermeable to air and oxygen free. The proper temperature for the bacterial species is maintained in the bioreactor

Biology

https://en.wikipedia.org/wiki?curid=19042654

Photofermentation

Photofermentation The bacteria are sustained with a carbohydrate diet consisting of simple saccharide molecules. The carbohydrates are typically sourced from agricultural or forestry waste. In addition to wild type forms of "Rhodopseudomonas palustris, s"cientists have used genetically modified forms to produce hydrogen as well. Other explorations include expanding the bioreactor system to hold a combination of bacteria, algae or cyanobacteria. Ethanol production is performed by the algae "Chlamydomonas reinhardtii", among other species, in cycling light and dark environments. The cycling of light and dark environments has also been explored with bacteria for hydrogen production, increasing hydrogen yield. The bacteria are typically fed with broken down agricultural waste or undesired crops, such as water lettuce or sugar beet molasses. The high abundance of such waste ensures the stable food source for the bacteria and productively uses human-produced waste. In comparison with dark fermentation, photofermentation produces more hydrogen per reaction and avoids the acidic end products of dark fermentation. The primary limitations of photofermentation as a sustainable energy source stem from the precise requirements of maintaining the bacteria in the bioreactor. Researchers have found it difficult to maintain a constant temperature for the bacteria within the bioreactor

Biology

https://en.wikipedia.org/wiki?curid=19042654

Photofermentation

Photofermentation Furthermore, the growth media for the bacteria must be rotated and refreshed without introducing air to the bioreactor system, complicating the already expensive bioreactor set up.

Biology

https://en.wikipedia.org/wiki?curid=19042654

Photofermentation

Gag/pol translational readthrough site (or Retroviral readthrough element) is a cis-regulatory element found in retroviruses. The readthrough site facilitates the mechanism of translation readthrough of the stop codon at the gag-pol junction producing the gag and pol fusion protein in certain retroviruses. Retroviruses whose gag and pol genes are in the same reading frame often depend upon approximately 5% read-through of the gag UAG termination codon to form the gag-pol polyprotein. This readthrough is usually dependent on a pseudoknot located eight nucleotides downstream of the stop codon (UAG). Sequence conservation is found in the second pseudoknot loop.

Biology

https://en.wikipedia.org/wiki?curid=19044032

Gag/pol translational readthrough site

Cytoneme Cytonemes are thin, cellular projections that are specialized for exchange of signaling proteins between cells. Cytonemes emanate from cells that make signaling proteins, extending directly to cells that receive signaling proteins. Cytonemes also extend directly from cells that receive signaling proteins to cells that make them. A cytoneme is a type of filopodium - a thin, tubular extension of a cell’s plasma membrane that has a core composed of tightly bundled, parallel actin filaments. Filopodia can extend more than 100 μm and have been measured as thin as 0.1 μm and as thick as 0.5 μm. Cytonemes with a diameter of approximately 0.2 μm and as long as 80 μm have been observed in the Drosophila wing imaginal disc. Many cell types have filopodia. The functions of filopodia have been attributed to pathfinding of neurons, early stages of synapse formation, antigen presentation by dendritic cells of the immune system, force generation by macrophages and virus transmission. They have been associated with wound closure, dorsal closure of Drosophila embryos, chemotaxis in Dictyostelium, Delta-Notch signaling, vasculogenesis, cell adhesion, cell migration, and cancer metastasis. Filopodia have been given various names: microspikes, pseudopods, thin filopodia, thick filopodia, gliopodia, myopodia, invadopodia, podosomes, telopodes, tunneling nanotubes and dendrites

Biology

https://en.wikipedia.org/wiki?curid=19045237

Cytoneme

Cytoneme The term cytoneme was coined to denote the presence of cytoplasm in their interior (cyto-) and their finger-like appearance (-neme), and to distinguish their role as signaling, rather than structural or force-generating, organelles. Filopodia with behaviors suggestive of roles in sensing patterning information were first observed in sea urchin embryos, and subsequent characterizations support the idea that they convey patterning signals between cells. The discovery of cytonemes in Drosophila imaginal discs correlated for the first time the presence and behavior of filopodia with a known morphogen signaling protein - decapentaplegic. Decapentaplegic is expressed in the wing disc by cells that function as a developmental organizer, and cytonemes that are responsive to decapentaplegic orient toward this developmental organizer. Receptors for signaling proteins are present in motile vesicles in cytonemes, and receptors for different signaling proteins segregate specifically to different types of cytonemes. In Drosophila, cytonemes have been found in wing and eye imaginal discs, trachea, lymph glands and ovaries. They have also been described in spider embryos, earwig ovaries, Rhodnius, Calpodes, earthworms, retroviral-infected cells, mast cells, B-lymphocytes and neutrophils. Recent observations suggest that cytonemes have also an important role during vertebrate development

Biology

https://en.wikipedia.org/wiki?curid=19045237

Cytoneme

Cytoneme Recent observations suggest that cytonemes also have an important role during development of the zebrafish neural plate where they transport Wnt8a and of the chick limb where they transport Sonic hedgehog.

Biology

https://en.wikipedia.org/wiki?curid=19045237

Cytoneme

Extra-Terrestrial Exposure Law The ( of the Code of Federal Regulations)—in force 1969–1977—was the popular name for regulations adopted by the National Aeronautics and Space Administration (NASA) in 1969 to formalize its "policy, responsibility and authority to guard the Earth against any harmful contamination … resulting from personnel, spacecraft and other property returning to the Earth after landing on or coming within the atmospheric envelope of a celestial body." Implemented before the Apollo 11 mission, it provided the legal authority for a quarantine period for the returning astronauts. The regulation defined "extraterrestrially exposed" as ...the state or condition of any person, property, animal or other form of life or matter whatever, who or which has (1) Touched directly or come within the atmospheric envelope of any other celestial body; or (2) Touched directly or been in close proximity (or been exposed indirectly to) any person, property, animal or other form of life or matter who or which has been extraterrestrially exposed by virtue of subparagraph (1) of this paragraph. Quarantining of astronauts on the first lunar missions was mandated in 1969 to prepare for "the remote possibility that they are harboring unknown lunar organisms that might endanger life on earth", and the Apollo 11 voyagers were kept in quarantine for 21 days after their liftoff from the moon. NASA filed notices establishing quarantine periods in the Federal Register for Apollo 11, Apollo 12, Apollo 13, and Apollo 14

Biology

https://en.wikipedia.org/wiki?curid=19050861

Extra-Terrestrial Exposure Law

Extra-Terrestrial Exposure Law After the completion of the Apollo 14 mission, NASA stopped enforcing the regulation, though it remained on the books. On April 30, 1971, NASA's acting administrator, Dr. George M. Low, was quoted as saying, On the basis of this analysis [of quarantine information from Apollo 14], as well as the results from the Apollo 11 and 12 flights, we have concluded there is no hazard to man, animals or plants in the lunar material...the interagency committee has recommended that further lunar missions need not be subject to quarantine. NASA revoked the rule in 1977 and the rule was formally removed from the Code of Federal Regulations in 1991.

Biology

https://en.wikipedia.org/wiki?curid=19050861

Extra-Terrestrial Exposure Law

Cleaved amplified polymorphic sequence The cleaved amplified polymorphic sequence (CAPS) method is a technique in molecular biology for the analysis of genetic markers. It is an extension to the Restriction Fragment Length Polymorphism (RFLP) method, using polymerase chain reaction (PCR) to more quickly analyse the results. Like RFLP, CAPS works on the principle that genetic differences between individuals can create or abolish restriction endonuclease restriction sites, and that these differences can be detected in the resulting DNA fragment length after digestion. In the CAPS method, PCR amplification is directed across the altered restriction site, and the products digested with the restriction enzyme. When fractionated by agarose or acrylamide gel electrophoresis, the digested PCR products will give readily distinguishable patterns of bands. Alternatively, the amplified segment can be analyzed by allele-specific oligonucleotide (ASO) probes, a process that can often be done by a simple dot blot.

Biology

https://en.wikipedia.org/wiki?curid=19057218

Cleaved amplified polymorphic sequence

Pectinifrons was a rangeomorph, a member of the Ediacara biota found at Mistaken Point, Newfoundland. It was a multi-branched organism with a comb-like appearance. It grew by adding fronds, then inflating them. List of Ediacaran genera

Biology

https://en.wikipedia.org/wiki?curid=19058526

Pectinifrons

Nuclear Receptor Signaling Atlas The (NURSA) was a United States National Institutes of Health-funded research consortium focused on nuclear receptors and nuclear receptor coregulators. Its co-principal investigators were Bert O'Malley and Neil McKenna of Baylor College of Medicine and Ron Evans of the Salk Institute. NURSA has now been retired and replaced by the Signaling Pathways Project (SPP).

Biology

https://en.wikipedia.org/wiki?curid=19062032

Nuclear Receptor Signaling Atlas

Refractory (planetary science) In planetary science, any material that has a relatively high equilibrium condensation temperature is called refractory. The opposite of refractory is volatile. The refractory group includes elements and compounds like metals and silicates (commonly termed rocks) which make up the bulk of the mass of the terrestrial planets and asteroids in the inner belt. A fraction of the mass of other asteroids, giant planets, their moons and trans-Neptunian objects is also made of refractory materials. The elements can be divided into several categories: The condensation temperatures are the temperatures at which 50% of the element will be in the form of a solid (rock) under a pressure of 10 bar. However, slightly different groups and temperature ranges are used sometimes. Refractory material are also often divided into refractory lithophile elements and refractory siderophile elements.

Biology

https://en.wikipedia.org/wiki?curid=19074000

Refractory (planetary science)

British Oceanographic Data Centre The (BODC) is a national facility for looking after and distributing data about the marine environment. BODC is the designated marine science data centre for the UK and part of the National Oceanography Centre (NOC) — primarily at its facility in Liverpool, with small number of its staff in Southampton. The centre provides a resource for science, education and industry, as well as the general public. The origins of BODC go back to 1969 when NERC created the British Oceanographic Data Service (BODS). Located at the National Institute of Oceanography, Wormley in Surrey, its purpose was to: In 1975 BODS was transferred to Bidston Observatory on the Wirral, near Liverpool, as part of the newly formed Institute of Oceanographic Sciences. The following year BODS became the Marine Information and Advisory Service (MIAS). Its primary activity was to manage the data collected from weather ships, oil rigs and data buoys. The data banking component of MIAS was restructured to form BODC in April 1989. Its mission was to 'operate as a world-class data centre in support of UK marine science'. BODC pioneered a start to finish approach to marine data management. This involved: In December 2004, BODC moved to the purpose-built Joseph Proudman Building on the campus of the University of Liverpool. A small number of its staff are based in the National Oceanography Centre (NOC), Southampton

Biology

https://en.wikipedia.org/wiki?curid=19075690

British Oceanographic Data Centre

British Oceanographic Data Centre BODC is one of six designated data centres that manage NERC's environmental data and has a number of national roles and responsibilities: BODC's international roles and responsibilities include: The following are a selection of the projects that BODC is or has been involved with:

Biology

https://en.wikipedia.org/wiki?curid=19075690

British Oceanographic Data Centre

Metisazone Methisazone (USAN) or metisazone (INN) is an antiviral drug that works by inhibiting mRNA and protein synthesis, especially in pox viruses. It has been used in the past to treat smallpox. Methisazone has been described as being used in prophylaxis since at least 1965. When isatin is treated with sodium hydride and methyl iodide, the acidic hydrogen is alkylated to product 2. Then, reaction of the ketone carbonyl with thiosemicarbazide (3) leads to methisazone (4).

Biology

https://en.wikipedia.org/wiki?curid=19084825

Metisazone

Alexander Davydov Alexander Sergeevich Davydov (, ) (26 December 1912 – 19 February 1993) was a Soviet and Ukrainian physicist. Davydov graduated from Moscow State University in 1939. In 1963-1990 he was Director of Institute for Theoretical Physics of the Ukrainian Academy of Sciences. His main contributions were in theory of absorption, scattering and dispersion of the light in molecular crystals. In 1948, he predicted the phenomenon that is known as "Davydov splitting" or "factor-group splitting", "the splitting of bands in the electronic or vibrational spectra of crystals due to the presence of more than one (interacting) equivalent molecular entity in the unit cell." In the period 1958-1960 he developed the theory of collective excited states in spherical and non-spherical nuclei, known as Davydov-Filippov Model and Davydov-Chaban Model. In 1973, Davydov applied the concept of molecular solitons in order to explain the mechanism of muscle contraction in animals. He studied theoretically the interaction of intramolecular excitations or excess electrons with autolocal breaking of the translational symmetry. These excitations are now known as Davydov solitons.

Biology

https://en.wikipedia.org/wiki?curid=19085993

Alexander Davydov

Debate about Cambrian lophotrochozoans Since 1990 there has been intense debate among paleontologists about the evolution in the Early Cambrian period of the "super-phylum" Lophotrochozoa, which is thought to include the modern molluscs, annelid worms and brachiopods, as well as their evolutionary "aunts" and "cousins". The name "halwaxiid" was formed by combining the names of two members of the proposed group, "Halkieria" and "Wiwaxia". The group was defined as a set of Early to Mid Cambrian animals that had: a "chain mail" coat of three concentric bands of small armor plates that are called sclerites; in some cases, a small cap-like shell at the front end and in some cases both ends. Some scientists are unhappy with this loose definition, arguing that such traits may have arisen convergently rather being inherited from a common ancestor. This objection suggests that the group is not monophyletic, in other words that the group does not contain all and only the descendants of a single common ancestor. In fact the originators of the term "halwaxiid" prefer an evolutionary "family tree" in which the halwaxiids are not monophyletic. Other fossil organisms became involved in the debate as there were plausible arguments for considering them closely related to the halkieriids or "Wiwaxia" or both

Biology

https://en.wikipedia.org/wiki?curid=19086594

Debate about Cambrian lophotrochozoans

Debate about Cambrian lophotrochozoans One was the more recently discovered "Orthrozanclus", which looked an intermediate between the halkieriids and "Wiwaxia" as it had a shell like that of halkieriids, and unmineralized sclerites and long spines like those of "Wiwaxia" – in fact the article which first described "Orthrozanclus" introduced the term "halwaxiid". New finds of "Odontogriphus" put this animal into play as well since, despite its lack of sclerites or shells, its feeding apparatus looks very like "Wiwaxia"’s. The siphogonotuchids, a very Early Cambrian group known only from isolated sclerites among the small shelly fossils, also appear in analyses as their sclerites suggest this group may have been close to the ancestors of halkieriids. Since 1995 several phylogenies, or evolutionary "family trees", have been suggested for these organisms. The position of "Wiwaxia" is highlighted, since the position of this organism has been central to the debate since 1990. The most intense part of the debate centers round "Wiwaxia". Conway Morris (1985) originally dismissed the earliest classification of "Wiwaxia" as a polychaete worm, because he thought there was little structural similarity between a polychaete's scale-like elytra and "Wiwaxia"’s sclerites, and because the arrangement of the sclerites, with quite different numbers in each band, showed no sign of the regular segmentation that is a feature of polychaetes

Biology

https://en.wikipedia.org/wiki?curid=19086594

Debate about Cambrian lophotrochozoans

Debate about Cambrian lophotrochozoans Instead he thought "Wiwaxia" was very similar to shell-less aplacophoran molluscs, that it must have moved on a mollusc-like muscular foot, and that its feeding apparatus looked like a primitive form of the molluscan radula, a tooth-bearing chitinous "tongue". Hence he classified it as a "sister" of the molluscs. When he briefly described the first articulated specimens of "Halkieria" in 1990, Conway Morris wrote of "the halkieriid-wiwaxiid body plan" and that the halkieriids might be close relatives of molluscs. Shortly after this in 1990 Butterfield published his first paper on "Wiwaxia". He argued that, since "Wiwaxia"’s sclerites appeared to be solid, they were not similar to the hollow sclerites of halkieriids. In fact he thought they were more similar to the chitinous bristles (setae) that project from the bodies of modern annelids and in some genera form leaf-like scales that cover the back like roof tiles - in composition, in detailed structure, in how they were attached to the body via follicle-like pockets in the skin, and in overall appearance. He also contended that Wiwaxia’s feeding apparatus, instead of being mounted in the middle of its "head", was just as likely to be mounted in two parts on the sides of the "head", an arrangement that is common in polychaetes. He therefore classified "Wiwaxia" as a polychaete. Conway Morris and Peel (1995) largely accepted Butterfield's arguments and treated "Wiwaxia" as an ancestor or "aunt" of the polychaetes

Biology

https://en.wikipedia.org/wiki?curid=19086594

Debate about Cambrian lophotrochozoans

Debate about Cambrian lophotrochozoans However they maintained that Wiwaxia's feeding apparatus was much more like a molluscan radula. They also argued that Wiwaxia was fairly closely related to and in fact descended from the halkieriids, as the sclerites are divided into similar groups, although those of halkieriids were much smaller, more numerous and hollow. They wrote that in 1994 Butterfield had found "Wiwaxia" sclerites that were clearly hollow. The cladogram they presented showed the halkieriids split into three groups: one as "aunts" of brachiopods, animals whose modern forms have bivalve shells but differ from molluscs in having muscular stalks and a distinctive feeding apparatus, the lophophore; the second group of halkieriids as "aunts" of both "Wiwaxia" and annelid worms; and the earliest halkieriids as "great aunts" of all of these. Marine biologist Amélie H. Scheltema "et al." (2003) argued that "Wiwaxia"’s feeding apparatus is very similar to the radulas of some modern shell-less aplacophoran molluscs, and that the sclerites of the two groups are very similar. They concluded that "Wiwaxia" was a member of a clade that includes molluscs. Danish zoologist Danny Eibye-Jacobsen (2004) regarded bristles as a feature shared by molluscs, annelids and brachiopods. Hence even if "Wiwaxia"’s sclerites closely resembled bristles, which he doubted, this would not prove that "Wiwaxia"’s closest relative were annelids

Biology

https://en.wikipedia.org/wiki?curid=19086594

Debate about Cambrian lophotrochozoans

Debate about Cambrian lophotrochozoans He also pointed out that the very different numbers of sclerites in the various zones of "Wiwaxia"’s body do not correspond to any reasonable pattern of segmentation. Since in his opinion "Wiwaxia" lacked other clearly polychaete features, he regarded this as an argument against classifying "Wiwaxia" as a polychaete. In his opinion there were no strong grounds for classifying "Wiwaxia" as a proto-annelid or a proto-mollusc. Caron, Scheltema "et al." (2006), in a paper about newly discovered and good specimens of "Odontogriphus", thought "Wiwaxia" bore little resemblance to polychaetes as it showed no signs of the segmentation, appendages in front of the mouth, or "legs" – all of which are typical polychaete features. On the other hand they thought the teeth on the feeding apparatus of both "Wiwaxia" and "Odontogriphus" strongly resembled those of a modern group of molluscs, Neomeniomorpha. Hence they classified "Wiwaxia" as an "aunt" and "Odontogriphus" as a "great aunt" of molluscs. Butterfield returned to the debate in 2006, repeating the arguments he presented in 1990 for regarding "Wiwaxia" as an early polychaete and adding that, while bristles are a feature of several groups, they appear as a covering over the back only in polychaetes

Biology

https://en.wikipedia.org/wiki?curid=19086594

Debate about Cambrian lophotrochozoans

Debate about Cambrian lophotrochozoans He also questioned whether the two or three rows of teeth in "Wiwaxia" and "Odontogriphus" could function in the same way as the belt-like molluscan radula with its many tooth-rows; on the other hand one group of polychaetes uses a single two-part "jaw" to scrape food off a substrate. While he agreed that "Wiwaxia" and "Odontogriphus" were very similar, he wrote, "… it certainly does not require that they be shoehorned into the same lineage. … the seemingly trivial distinction between these two taxa is exactly what is expected at the divergence points leading from a last common ancestor to extant phyla." Butterfield (2006) accepted that "Wiwaxia" and "Odontogriphus" were closely related, but argued that they were stem-group polychaetes rather than stem-group molluscs. In his opinion the feeding apparatus of these organisms, with consisted of two or at most four rows of teeth, could not perform the functions of the "belt-like" molluscan radula with their numerous tooth-rows; the different tooth-rows in both "Wiwaxia" and "Odontogriphus" tooth-rows also have noticeably different shapes, while those of molluscan radulae are produced one after the other by the same group of "factory" cells and therefore are almost identical. He also regarded lines running across the middle region of "Odontogriphus" fossils as evidence of external segmentation, since the lines are evenly spaced and run exactly at right angles to the long axis of the body

Biology

https://en.wikipedia.org/wiki?curid=19086594

Debate about Cambrian lophotrochozoans

Debate about Cambrian lophotrochozoans As in his earlier papers, Butterfield emphasized the similarities of internal structure between "Wiwaxia"’s sclerites and the bristles of polychaetes, and the fact that polychaetes are the only modern organisms in which some of the bristles form a covering over the back. In 2007 Conway Morris and Caron described a new fossil, "Orthrozanclus", which had a mineralized shell like that of halkieriids, and unmineralized sclerites and long spines like those of "Wiwaxia" – and, like both of these, a soft underside which they interpreted as a muscular foot, and a similar arrangement of the sclerites into three concentric bands. Some of "Orthrozanclus"’s sclerites appear to have been hollow, as the specimen includes what look like internal castings. They took this find as evidence that the halkieriids, "Wiwaxia" and "Orthrozanclus" were very closely related and formed the group "halwaxiids". However the simplest "family tree" faces an obstacle: the siphogonuchitids appear in earlier rocks and had "mineralized" sclerites. Hence Conway Morris and Caron found it necessary to consider two more complex family trees, concluding that "Hypothesis 1" fitted the available data better, but fell apart if there were minor changes in the characteristics used: Conway Morris and Caron (2007) published the first description of "Orthrozanclus reburrus"

Biology

https://en.wikipedia.org/wiki?curid=19086594

Debate about Cambrian lophotrochozoans

Debate about Cambrian lophotrochozoans This resembled the halkieriids in having concentric bands of sclerites, although only two and not mineralized; and "one" shell at what was presumed to be the front and which was similar in shape to "Halkieria"’s front shell. It also had long spines rather like those of "Wiwaxia". Conway Morris and Caron regarded this creature as evidence that the "halwaxiids" were a valid taxon and were monophyletic, in other words shared a common ancestor with each other and with no other organism. They published "two" cladograms, representing alternative hypotheses about the evolution of the lophotrochozoa, the lineage that includes molluscs, annelids and brachiopods: Most of the debate has been about halkieriids' relationship to molluscs, annelids and brachiopods. However a paper published in 2008 argued that halkieriids were closely related to chancelloriids, which have been generally regarded as sponges. Halkieriid sclerites were known for a long time as elements of the small shelly fossils. The first articulated specimens, with all their hard parts together, were collected in 1989 and were described briefly in 1990 by Conway Morris and Peel (1990)

Biology

https://en.wikipedia.org/wiki?curid=19086594

Debate about Cambrian lophotrochozoans

Debate about Cambrian lophotrochozoans The same authors produced a more detailed analysis in 1995, which divided the halkieriids into three groups: one as "aunts" of brachiopods, animals whose modern forms have bivalve shells but differ from molluscs in having muscular stalks and a distinctive feeding apparatus, the lophophore; the second group of halkieriids as "aunts" of both "Wiwaxia" and annelid worms; and the earliest halkieriids as "great aunts" of all of these. In 2003 Cohen, Holmer and Luter supported the halkieriid-brachiopod relationship, suggesting that brachiopods may have arisen from a halkieriid lineage that developed a shorter body and larger shells, and then folded itself and finally grew a stalk out of what used to be the back. Vinther and Nielsen (2005) proposed instead that "Halkieria" was a crown group mollusc, in other words more similar to modern molluscs than to annelids, brachiopods or any intermediate groups. They argued that: "Halkieria"’s sclerites resembled those of the modern solenogaster aplacophoran shell-less molluscs, of some modern polyplacophoran molluscs, which have several shell plates, and of the Ordovician polyplacophoran "Echinochiton"; "Halkieria"’s shells are more similar to the shells of conchiferan molluscs, since shells of both of these groups show no trace of the canals and pores seen in polyplacophoran shell plates; the bristles of brachiopods and annelids are similar to each other but not to "Halkieria"’s sclerites

Biology

https://en.wikipedia.org/wiki?curid=19086594

Debate about Cambrian lophotrochozoans

Debate about Cambrian lophotrochozoans However Conway Morris (2006) criticized Vinther and Nielsen's classification of "Halkieria" as a crown group mollusc, on the grounds that the growth of the spicules in the aplacophorans and polyplacophorans is not similar to the method of growth deduced for the complex halkieriid sclerites; in particular, he said, the hollow spines of various molluscs are not at all like the halkieriid sclerites with their complex internal channels. Conway Morris repeated his earlier conclusion that halkieriids were close to the ancestors of both molluscs and brachiopods. In their description of the newly discovered "Orthrozanclus" (2007), which has similarities to both "Wiwaxia" and the halkieriids, Conway Morris and Caron also took account of the siphogonuchitids, a group known only from isolated mineralized sclerites that resemble those of the halkieriids. They proposed the two "family trees" described above: Porter (2008) revived an early 1980s idea that the sclerites of "Halkieria" are extremely similar to those of chancelloriids. These were sessile, bag-like, radially symmetric organisms with an opening at the top. Since their fossils show no signs of a gut or other organs, chancelloriids were originally classified as some kind of sponge. Butterfield and Nicholas (1996) argued that they were closely related to sponges on the grounds that the detailed structure of chancellorid sclerites is similar to that of fibers of spongin, a collagen protein, in modern keratose (horny) demosponges

Biology

https://en.wikipedia.org/wiki?curid=19086594

Debate about Cambrian lophotrochozoans

Debate about Cambrian lophotrochozoans However Janussen, Steiner and Zhu (2002) opposed this view on several grounds, including that: the silica-based spines of demosponges are solid, while chancellorid sclerites are hollow, probably made of aragonite, and filled with soft tissues connected to the rest of the animal at the bases of the sclerites; sponges have loosely bound-together skins called pinacoderms, which are only one cell thick, while the skins of chancellorids were much thicker and show signs of connective structures called belt desmosomes. In their opinion the presence of belt desmosomes made chancellorids members of the Epitheliazoa, the next higher taxon above the Porifera, to which sponges belong. They thought it was difficult to say whether chancellorids were members of the Eumetazoa, "true animals" whose tissues are organized into Germ layers: chancellorids' lack of internal organs would seem to exclude them from the Eumetazoa; but possibly chancellorids were descended from Eumetazoans that lost these features after becoming sessile filter-feeders. The sclerites of halkieriids and chancelloriids resemble each other at all levels: both have an internal "pulp cavity" and a thin external organic layer; the walls are made of the same material, aragonite; the arrangement of the aragonite fibers in each is the same, running mainly from base to tip but with each being closer to the surface at the end nearest the tip

Biology

https://en.wikipedia.org/wiki?curid=19086594

Debate about Cambrian lophotrochozoans

Debate about Cambrian lophotrochozoans It is extremely improbable that totally unrelated organisms could have developed such similar sclerites independently, but the huge difference in the structures of their bodies makes it hard to see how they could be closely related. This dilemma may be resolved in various ways:

Biology

https://en.wikipedia.org/wiki?curid=19086594

Debate about Cambrian lophotrochozoans

Alfred Kohn (22 February 1867 – 15 January 1959) was the head of the Institute of Histology at the Medical Faculty of German University in Prague for 26 years. He entered the history of medicine by discovery of the nature and origin of parathyroid glands and by pioneering research into chromaffin cells and sympathetic paraganglia. Kohn's papers on the pituitary, interstitial cells of testes, and ovaries are also related to endocrinology. All his studies are based on descriptive and comparative histological and embryological observations. Kohn was twice the dean of German Medical Faculty, and a member or honorary member of many important scientific societies. He was repeatedly nominated for Nobel Prize for physiology and medicine. For his Jewish origin he was expelled from Deutsche Gesellschaft der Wissenschaften und Künste für die Tschechoslowakische Republik in 1939 and transported to Terezin (Theresienstadt) ghetto in 1943. After the war he lived in Prague. On the occasion of his 90th birthday he was elected honorary president of Anatomische Gesellschaft and awarded by the Czechoslovak Order of Labour. died in 1959. He was one of the outstanding personalities that Prague gave to the world of science.

Biology

https://en.wikipedia.org/wiki?curid=19105502

Alfred Kohn

Grand Prix Charles-Leopold Mayer The Grand Prix Charles-Léopold Mayer (Charles-Léopold Mayer Prize) is awarded annually by the Académie des Sciences (French Academy of Sciences) de l'Institut de France (the French Institute) to researchers who have performed outstanding work in the biological sciences; especially in the areas of cell or molecular biology. Citizens or residents of any nation are eligible for the prize, but it is never awarded to individuals of the same nation two years in a row, nor is the prize ever presented to scholars who are more than 65 years of age. Between the first presentation of the award in 1961 and the year 2009, there have been more than 60 laureates, eleven of whom subsequently received the Nobel Prize in medicine, physiology, or chemistry. The prize is named after French biochemist Charles Léopold Mayer. Source: Académie des sciences

Biology

https://en.wikipedia.org/wiki?curid=19112140

Grand Prix Charles-Leopold Mayer

Stem cell transplantation for articular cartilage repair Mesenchymal stem cells (MSCs) are multipotent cells found in multiple human adult tissues including bone marrow, synovial tissues, and adipose tissues. Since they are derived from the mesoderm, they have been shown to differentiate into bone, cartilage, muscle, and adipose tissue. MSCs from embryonic sources have shown promise scientifically while creating significant controversy. As a result, many researchers have focused on adult stem cells, or stem cells isolated from adult humans that can be transplanted into damaged tissue. Because of their multi-potent capabilities, mesenchymal stem cell (MSC) lineages have been used successfully in animal models to regenerate articular cartilage and in human models to regenerate bone. Recent research demonstrates that articular cartilage may be able to be repaired via percutaneous introduction of mesenchymal stem cells (MSC's). Research into MSC's has exploded in recent years. As an example, a PubMed search for the year 1999 reveals about 90 papers published under the MESH heading of “Mesenchymal Stem Cells”, the same search ran for the year 2007 reveals more than 4,000 entries. The most commonly used source of MSC's is bone marrow aspirate. Most of the adult bone marrow consists of blood cells in various stages of differentiation. These marrow components can be divided into plasma, red blood cells, platelets, and nucleated cells. The adult stem cell fraction is present in the nucleated cells of the marrow

Biology

https://en.wikipedia.org/wiki?curid=19115497

Stem cell transplantation for articular cartilage repair

Stem cell transplantation for articular cartilage repair Most of these cells are CD34+ heme progenitors (destined to differentiate into blood components), while very few are actually MSC's capable of differentiating into bone, cartilage, or muscle. As a result, that leaves the very small number of MSC's in the marrow as cells capable of differentiating into tissues of interest to joint preservation. Of note, this may be one of the reasons that commercially available centrifuge systems that concentrate marrow nucleated cells have not shown as much promise in animal research for cartilage repair as have approaches where MSC's are expanded in culture to greater numbers. Marrow nucleated cells are used every day in regenerative orthopedics. The knee microfracture surgery technique relies on the release of these cells into a cartilage lesion to initiate fibrocartilage repair in osteochondral defects. In addition, this cell population has also been shown to assist in the repair of non-union fractures. For this application, bed side centrifugation is commonly used. Again, these techniques produce a very dilute MSC population, usually a yield of 1 in 10,000–1,000,000 of the nucleated cells. Despite this low number of MSC's, isolated bone marrow nucleated cells implanted into degenerated human peripheral joints have shown some promise for joint repair. As the number of MSC's that can be isolated from bone marrow is fairly limited, most research in cartilage regeneration has focused on the use of culture expanded cells

Biology

https://en.wikipedia.org/wiki?curid=19115497

Stem cell transplantation for articular cartilage repair

Stem cell transplantation for articular cartilage repair This method can expand cell numbers by 100-10,000 fold over several weeks. Once these MSCs are ready for re-implanation, they are usually transferred with growth factors to allow for continued cell growth and engraftment to the damaged tissue. At some point, a signal is introduced (either in culture or after transplant to the damaged tissue) for the cells to differentiate into the end tissue (in this discussion, cartilage). Until recently, the use of cultured mesenchymal stem cells to regenerate cartilage has been primarily in research with animal models. There are now, however, two published case reports of the above technique being used to successfully regenerate articular and meniscus cartilage in human knees. This technique has yet to be shown effective in a study involving a larger group of patients, however the same team of researchers have published a large safety study (n=227) showing fewer complications than would normally be associated with surgical procedures. Another team used a similar technique for cell extraction and ex vivo expansion but cells were embedded within a collagen gel before being surgically re-implanted. They reported a case study in which a full-thickness defect in the articular cartilage of a human knee was successfully repaired. While the use of cultured mesenchymal stem cells has shown promising results, a more recent study using uncultured MSC's has resulted in full thickness, histologically confirmed hyaline cartilage regrowth

Biology

https://en.wikipedia.org/wiki?curid=19115497

Stem cell transplantation for articular cartilage repair

Stem cell transplantation for articular cartilage repair Researchers evaluated the quality of the repair knee cartilage after arthroscopic microdrilling (also microfracture) surgery followed by post-operative injections of autologous peripheral blood progenitor cells (PBPC) in combination with hyaluronic acid(HA).

Biology

https://en.wikipedia.org/wiki?curid=19115497

Stem cell transplantation for articular cartilage repair

Continuous Plankton Recorder The (CPR) Survey is one of the longest running marine biological monitoring programmes in the world. Started in 1931 by Sir Alister Hardy and Sir Cyril Lucas, the Survey has provided marine scientists with their only measure of plankton communities on a pan-oceanic scale. Today the CPR Survey is operated by the Marine Biological Association(MBA), located in Plymouth, UK. Uniquely, the CPR Survey’s methods of sampling and plankton analysis remain unchanged since 1948, providing a spatio-temporally comprehensive > 70 year record of marine plankton dynamics. The CPR is a plankton sampling instrument designed to be towed from merchant ships, or ships of opportunity, on their normal sailings. As of December 31, 2007, CPRs have been towed a total of by 278 ships since the survey’s inception. Recorders have been towed in all oceans of the world, the Mediterranean, Baltic and North Seas and in freshwater lakes. However, MBA CPR sampling primarily focuses on the northwest European shelf and the Northeast and Northwest Atlantic, with these regions undergoing monthly sampling; regular sampling is also now carried out in the North Pacific. Additionally, sister CPR surveys, not conducted by the MBA but using similar methodology, are operated from the United States, Australia, India, Cyprus, Brazil, South Africa, France and Japan, as part of the Global Alliance of Surveys (www.globalcpr.org) The CPR is towed at a depth of approximately 10 metres

Biology

https://en.wikipedia.org/wiki?curid=19135750

Continuous Plankton Recorder

Continuous Plankton Recorder Water passes through the CPR and plankton are filtered onto a slow-moving band of silk (270 micrometre mesh size) and covered by a second silk. The silks and plankton are then spooled into a storage tank containing formalin. On return to the laboratory, the silk is removed from the mechanism and divided into samples representing of tow. CPR samples are analyzed in two ways. Firstly, the Phytoplankton Colour Index (PCI) is determined for each sample. The colour of the silk is evaluated against a standard colour chart and given a 'green-ness' value based on the visual discoloration of the CPR silk produced by green chlorophyll pigments; the PCI is a semi-quantitative estimate of phytoplankton biomass. In this way the PCI takes into account the chloroplasts of broken cells and small phytoplankton which cannot be counted during the microscopic analysis stage. After determination of the PCI, microscopic analysis is undertaken for each sample, and individual phytoplankton and zooplankton taxa are identified and counted. Nearly 500 phyto- and zooplankton taxa have been identified on CPR samples since 1948. Due to its long time-series, comprehensive spatial coverage and methodological consistency, the Survey is a unique ecological dataset which has provided invaluable insights into numerous aspects of plankton dynamics and ecology

Biology

https://en.wikipedia.org/wiki?curid=19135750

Continuous Plankton Recorder

Continuous Plankton Recorder Key areas of research include: Their research results show that warmer water species of plankton are moving northwards towards the colder North Atlantic at a rate of about per year and that some plankton species have moved north over the course of 50 years due to regional climate warming. But they are not replacing the cold water species in similar abundance. The open oceans are not yet subject to eutrophication or changes due to acidification though the number of microplastics collected on CPR samples is increasing. It has detected a new species in the North Atlantic which may be the first evidence of Trans-Arctic species migration in modern times.

Biology

https://en.wikipedia.org/wiki?curid=19135750

Continuous Plankton Recorder

Nutriomics is an omics study for nutrition and energy metabolism related genes and proteins. is a new field where traditional nutrition researchers adopt genomics technology such as large scale microarray analysis with food intake.

Biology

https://en.wikipedia.org/wiki?curid=19142174

Nutriomics

Nutrient agar is a general purpose medium supporting growth of a wide range of non-fastidious organisms. It typically contains (mass/volume): These ingredients are combined and boiled for approximately one minute to ensure they are mixed and then sterilized by autoclaving, typically at for 15 minutes. Then they are cooled to around and poured into Petri dishes which are covered immediately. Once the dishes hold solidified agar, they are stored upside down and are often refrigerated until used. Inoculation takes place on warm dishes rather than cool ones: if refrigerated for storage, the dishes must be rewarmed to room temperature prior to inoculation.

Biology

https://en.wikipedia.org/wiki?curid=19146762

Nutrient agar

Winter rest (from the German term "Winterruhe") is a state of reduced activity of plants and warm-blooded animals living in extratropical regions of the world during the more hostile environmental conditions of winter. In this state, they save energy during cold weather while they have limited access to food sources. Deciduous trees lose their foliage in the winter. Tree growth rings are a result of winter rest, as there is rapid growth in the warmer spring, then slower growth later in the year. Perennial and biennial herbaceous plants lose their frost-sensitive, above-ground parts before the winter, and regrow in the spring. Herbaceous plants that are annual, producing seeds before the winter, can also be considered to have winter rest in some form, because their seeds may stay inactive over the winter before germinating. Annual plants which have seeds that germinate before winter also have winter rest. Winter cereals, for example, which are sown in the fall and germinate before the frost, become dormant during the winter and actually require a few weeks of cold before they are able to flower. in an animal is different from true hibernation, since the metabolism is not reduced drastically. The body temperature is not significantly lowered, however the heart rate is reduced. This means that animals like the raccoon can quickly become active again if temperatures rise or the snow melts. Other animals that winter rest are badgers and brown bears.

Biology

https://en.wikipedia.org/wiki?curid=19151199

Winter rest

Evolutionary trap The term evolutionary trap has retained several definitions associated with different biological disciplines. Within evolutionary biology, this term has been used sporadically to refer to cases in which an evolved, and presumably adaptive, trait has suddenly become maladaptive, leading to the extinction of the species. Within behavioral and ecological sciences, evolutionary traps occur when rapid environmental change triggers organisms to make maladaptive behavioral decisions. While these traps may take place within any type of behavioral context (e.g. mate selection, navigation, nest-site selection), the most empirically and theoretically well-understood type of evolutionary trap is the ecological trap which represents maladaptive habitat selection behavior. Witherington demonstrates an interesting case of a "navigational trap". Over evolutionary time, hatchling sea turtles have evolved the tendency to migrate toward the light of the moon upon emerging from their sand nests. However, in the modern world, this has resulted in them tending to orient towards bright beach-front lighting, which is a more intense light source than the moon. As a result, the hatchlings migrate up the beach and away from the ocean where they exhaust themselves, desiccate and die either as a result of exhaustion, dehydration or predation. Habitat selection is an extremely important process in the lifespan of most organisms

Biology

https://en.wikipedia.org/wiki?curid=19154280

Evolutionary trap

Evolutionary trap That choice affects nearly all of an individual’s subsequent choices, so it may not be particularly surprising the type of evolutionary trap with the best empirical support is the ecological trap. Even so, traps may be relatively difficult to detect and so the lack of evidence for other types of evolutionary trap may be a result of the paucity of researchers looking for them coupled with the demanding evidence required to demonstrate their existence.

Biology

https://en.wikipedia.org/wiki?curid=19154280

Evolutionary trap

Involution (medicine) Involution is the shrinking or return of an organ to a former size. At a cellular level, involution is characterized by the process of proteolysis of the basement membrane (basal lamina), leading to epithelial regression and apoptosis, with accompanying stromal fibrosis. The consequent reduction in cell number and reorganization of stromal tissue leads to the reduction in the size of the organ. The thymus continues to grow between birth and puberty and then begins to atrophy, a process directed by the high levels of circulating sex hormones. Proportional to thymic size, thymic activity (T cell output) is most active before puberty. Upon atrophy, the size and activity are dramatically reduced, and the organ is primarily replaced with fat. The atrophy is due to the increased circulating level of sex hormones, and chemical or physical castration of an adult results in the thymus increasing in size and activity. Involution is the process by which the uterus is transformed from pregnant to non-pregnant state. This period is characterized by the restoration of ovarian function in order to prepare the body for a new pregnancy. It is a physiological process occurring after parturition; the hypertrophy of the uterus has to be undone since it does not need to house the fetus anymore. This process is primarily due to the hormone oxytocin. The completion of this period is defined as when the diameter of the uterus returns to the size it is normally during a woman's menstrual cycle

Biology

https://en.wikipedia.org/wiki?curid=19157294

Involution (medicine)

Involution (medicine) During pregnancy until after birth, mammary glands grow steadily to a size required for optimal milk production. At the end of breastfeeding, the number of cells in the mammary gland becomes reduced until approximately the same number is reached as before the start of pregnancy.

Biology

https://en.wikipedia.org/wiki?curid=19157294

Involution (medicine)

Evolve (TV series) Evolve is a 2008 documentary television series on History. The series premiere, "Eyes", was nominated for an Emmy for Outstanding Science, Technology and Nature Programming. Each episode attempts to explain the evolutionary origins of a particular trait of living creatures: for example, Tyrannosaurus rex's 13-inch teeth, the gecko's "Velcro-like" toe pads, and the bald eagle's "telescopic" vision capable of spotting a hare a mile away. To date, there are 11 episodes, which are available to buy in a compilation box set. The box incorrectly lists 13 episodes but does list the correct 11 episode running time total. Topics are of the episode as named. The dates of the episodes vary from the different sources available on the internet. The following dates have been compiled from different TV listing websites. Only the airdate of the initial episode is consistent among 4 sources:

Biology

https://en.wikipedia.org/wiki?curid=19163660

Evolve (TV series)

N-back The n-back task is a continuous performance task that is commonly used as an assessment in psychology and cognitive neuroscience to measure a part of working memory and working memory capacity. The n-back was introduced by Wayne Kirchner in 1958. Some researchers have argued that n-back training may increase IQ, but evidence is low quality and mixed. The subject is presented with a sequence of stimuli, and the task consists of indicating when the current stimulus matches the one from "n" steps earlier in the sequence. The load factor "n" can be adjusted to make the task more or less difficult. To clarify, the visual n-back test is similar to the classic memory game of "Concentration". However, instead of different items that are in a fixed location on the game board, there is only one item, that appears in different positions on the game board during each turn. "1-N" means that you have to remember the position of the item, "one" turn back. "2-N" means that you have to remember the position of the item "two" turns back, and so on. For example, an auditory three-back test could consist of the experimenter reading the following list of letters to the test subject: The subject is supposed to indicate when the letters marked in bold are read, because those correspond to the letters that were read three steps earlier. The "n"-back task captures the active part of working memory

Biology

https://en.wikipedia.org/wiki?curid=19170647

N-back

N-back When "n" equals 2 or more, it is not enough to simply keep a representation of recently presented items in mind; the working memory buffer also needs to be updated continuously to keep track of what the current stimulus must be compared to. To accomplish this task, the subject needs to both maintain and manipulate information in working memory. The dual-task n-back task is a variation that was proposed by Susanne Jaeggi et al. in 2003. In the dual-task paradigm, two independent sequences are presented simultaneously, typically using different modalities of stimuli, such as one auditory and one visual. Several smart phone apps and online implementations of the Dual N-Back task exist . The "n"-back task was developed by Wayne Kirchner for his research into short-term memory; he used it to assess age differences in memory tasks of "rapidly changing information". There is some question about the construct validity of the "n"-back task. While the task has strong face validity and is now in widespread use as a measure of working memory in clinical and experimental settings, there are few studies which explore the convergent validity of the "n"-back task with other measures of working memory. Those studies have largely revealed weak or modest correlations between individuals' performance on the "n"-back task and performance on other standard, accepted assessments of working memory. There are two main hypotheses for this weak correlation between the "n"-back task and other working memory assessments

Biology

https://en.wikipedia.org/wiki?curid=19170647

N-back

N-back One proposal is that the "n"-back task assesses different "sub-components" of working memory than do other assessments. A more critical explanation is that rather than primarily assessing working memory, performance on the "n"-back task depends on "familiarity- and recognition-based discrimination processes," whereas valid assessments of working memory demand "active recall." Whatever the cause of the performance differences between the "n"-back and other assessments of working memory, some researchers stress the need for further exploration of the construct validity of the "n"-back task. Performance on the "n"-back task seems to be more closely correlated with performance on measures of fluid intelligence than it is with performance on other measures of working memory (which is also correlated with performance on measures of fluid intelligence). In the same vein, training on the "n"-back task appears to improve performance on subsequent fluid intelligence assessments, especially when the training is at a higher "n"-value. A 2008 research paper claimed that practicing a dual "n"-back task can increase fluid intelligence (Gf), as measured in several different standard tests. This finding received some attention from popular media, including an article in "Wired". However, a subsequent criticism of the paper's methodology questioned the experiment's validity and took issue with the lack of uniformity in the tests used to evaluate the control and test groups

Biology

https://en.wikipedia.org/wiki?curid=19170647

N-back

N-back For example, the progressive nature of Raven's Advanced Progressive Matrices (APM) test may have been compromised by modifications of time restrictions (i.e., 10 minutes were allowed to complete a normally 45-minute test). The authors of the original paper later addressed this criticism by citing research indicating that scores in timed administrations of the APM are predictive of scores in untimed administrations. The 2008 study was replicated in 2010 with results indicating that practicing single n-back may be almost equal to dual n-back in increasing the score on tests measuring Gf (fluid intelligence). The single n-back test used was the visual test, leaving out the audio test. In 2011, the same authors showed long-lasting transfer effect in some conditions. Two studies published in 2012 failed to reproduce the effect of dual n-back training on fluid intelligence. These studies found that the effects of training did not transfer to any other cognitive ability tests. In 2014, a meta-analysis of twenty studies showed that n-back training has small but significant effect on Gf and improve it on average for an equivalent of 3-4 points of IQ. In January 2015, this meta-analysis was the subject of a critical review due to small-study effects. The question of whether "n"-back training produces real-world improvements to working memory remains controversial. The "n"-back is now in use outside experimental, clinical, and medical settings

Biology

https://en.wikipedia.org/wiki?curid=19170647

N-back

N-back Tutoring companies utilize versions of the task (in conjunction with other cognitive tasks) to allegedly improve the fluid intelligence of their clients. Tutoring companies and psychologists also utilize the task to improve the focus of individuals with ADHD and to rehabilitate sufferers of traumatic brain injury; experiments have found evidence that practice with the task helps these individuals focus for up to eight months following training. However, much debate remains about whether training on the "n"-back and similar tasks can improve performance in the long run or whether the effects of training are transient, and if the effects of training "n"-back generalize to general cognitive processing, for instance, to fluid intelligence. Despite the claims of commercial providers, there are some researchers who question whether the results of memory training are transferable. Researchers from the University of Oslo published results of the meta-analytical review analyzing various studies on memory training techniques (including n-back) and concluded that "training programs give only near-transfer effects, and there is no convincing evidence that even such near-transfer effects are durable." Meta-analysis of 24 "n"-back neuroimaging studies have shown that during this task the following brain regions are consistently activated: lateral premotor cortex; dorsal cingulate and medial premotor cortex; dorsolateral and ventrolateral prefrontal cortex; frontal poles; and medial and lateral posterior parietal cortex.

Biology

https://en.wikipedia.org/wiki?curid=19170647

N-back