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Urmetazoan The is the hypothetical last common ancestor of all animals (hypothetical in this instance doesn't mean the organism in question did not exist, it did, just that it's ultimate nature is hypothetical since it no longer exists). It was undoubtedly a flagellate marine eukaryote, but beyond this its form is difficult to determine because the relationships of animal phyla are not completely understood. All animals are posited by biologists to have evolved from a flagellated eukaryote. Their closest known living relatives are the choanoflagellates – collared flagellates whose cell morphology is similar to the choanocyte cells of certain sponges. Molecular studies place animals in a supergroup called the opisthokonts, which also include the choanoflagellates, fungi, and a few small parasitic protists. The name comes from the posterior location of the flagellum in motile cells, such as most animal spermatozoa, whereas other eukaryotes tend to have anterior flagella. Five different hypotheses for the animals' last common ancestor have been put forward. The relationships between the different animal phyla themselves are not well-resolved, so discriminating between the hypotheses is difficult. Under the placula hypothesis, the last common ancestor of animals was a somewhat amorphous blob, lacking any form of symmetry or axis. The centre of this blob became raised slightly from the sediment, to create a cavity which assisted feeding on the sea floor below

Biology

https://en.wikipedia.org/wiki?curid=21382102

Urmetazoan

Urmetazoan As this cavity developed, it became deeper and deeper, until the organisms resembled a thimble, with an inside and outside. Some sponges and cnidaria have this kind of body form. The development of the bilaterian body plan follows from this hypothesis; the urbilaterian would develop its symmetry as one end of the placula became adapted for moving forwards, which would result in a left-right symmetry. This idea, proposed by Otto Bütschli, suggests that metazoa are derived from a planula; that is, the larva of certain cnidaria. Under this hypothesis, the larva became sexually mature through paedomorphosis, so could reproduce without passing through a sessile phase. The gastraea hypothesis was proposed by Ernst Haeckel, shortly after his work on the calcareous sponges. He proposed that this group of sponges is monophyletic with all eumetazoans, including the bilaterians. This suggested that the gastrulation and the gastrula stage are universal for eumetazoans. It has been perceived as problematic that a gastrulation by invagination is by no means universal among eumetazoans. Only recently has an invagination been confirmed in a Calcarea sponge, albeit too early to form a remaining inner space (archenteron). This hypothesis was developed by Gösta Jägersten as an adaptation of Ernst Haeckel's Gastraea hypothesis. He proposed that the Bilaterogastraea had a two-stage life cycle, with a pelagic juvenile and a benthic adult stage

Biology

https://en.wikipedia.org/wiki?curid=21382102

Urmetazoan

Urmetazoan The invagination of the original gastrula stage he saw as bilaterally symmetric rather than radially symmetric. Proposed by Élie Metchnikoff.

Biology

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Urmetazoan

Standard flowgram format (SFF) is a binary file format used to encode results of pyrosequencing from the 454 Life Sciences platform for high-throughput sequencing. SFF files can be viewed, edited and converted with DNA Baser SFF Workbench (graphic tool), or converted to FASTQ format with sff2fastq or seq_crumbs. NCBI reference for SFF format

Biology

https://en.wikipedia.org/wiki?curid=21389230

Standard flowgram format

Research into centenarians A centenarian is a person who has attained the age of 100 years or more. Research on centenarians is becoming increasingly widespread with clinical and general population studies now having been conducted in France, Hungary, Japan, Italy, Finland, Denmark, the United States, and China. Centenarians are the fastest-growing demographic in much of the developed world. By 2030 it is expected that there will be around a million centenarians worldwide. In the United States, a 2010 Census Bureau report found that more than 80 percent of centenarians are women. Research carried out in Italy suggests that healthy centenarians have high levels of vitamin A and vitamin E and that this seems to be important in guaranteeing their extreme longevity. Other research contradicts this and has found that these findings do not apply to centenarians from Sardinia, for whom other factors probably play a more important role. A preliminary study carried out in Poland showed that, in comparison with young healthy female adults, centenarians living in Upper Silesia had significantly higher red blood cell glutathione reductase and catalase activities and higher, although insignificantly, serum levels of vitamin E. Researchers in Denmark have also found that centenarians exhibit a high activity of glutathione reductase in red blood cells. In this study, those centenarians having the best cognitive and physical functional capacity tended to have the highest activity of this enzyme

Biology

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Research into centenarians

Research into centenarians Some research suggests that high levels of vitamin D may be associated with longevity. Other research has found that people having parents who became centenarians have an increased number of naïve B-cells. It is believed that centenarians possess a different adiponectin isoform pattern and have a favorable metabolic phenotype in comparison with elderly individuals. Research carried out in the United States has found that people are much more likely to celebrate their 100th birthday if their brother or sister has reached the age. These findings, from the New England Centenarian Study in Boston, suggest that the sibling of a centenarian is four times more likely to live past 90 than the general population. Other research carried out by the New England Centenarian Study has identified 150 genetic variations that appeared to be associated with longevity which could be used to predict with 77 percent accuracy whether someone would live to be at least 100. Research also suggests that there is a clear link between living to 100 and inheriting a hyperactive version of telomerase, an enzyme that prevents cells from ageing. Scientists from the Albert Einstein College of Medicine in the US say centenarian Ashkenazi Jews have this mutant gene. Many centenarians manage to avoid chronic diseases even after indulging in a lifetime of serious health risks

Biology

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Research into centenarians

Research into centenarians For example, many people in the New England Centenarian Study experienced a century free of cancer or heart disease despite smoking as many as 60 cigarettes a day for 50 years. The same applies to people from Okinawa in Japan, where around half of supercentenarians had a history of smoking and one-third were regular alcohol drinkers. It is possible that these people may have had genes that protected them from the dangers of carcinogens or the random mutations that crop up naturally when cells divide. Similarly, centenarian research carried out at the Albert Einstein College of Medicine found that the individuals studied had less than sterling health habits. As a group, for example, they were more obese, more sedentary and exercised less than other, younger cohorts. The researchers also discovered three uncommon genotype similarities among the centenarians: one gene that causes HDL cholesterol to be at levels two- to three-fold higher than average; another gene that results in a mildly underactive thyroid; and a functional mutation in the human growth hormone axis that may be a safeguard from aging-associated diseases. It is well known that the children of parents who have a long life are also likely to reach a healthy age, but it is not known why, although the inherited genes are probably important. A variation in the gene FOXO3A is known to have a positive effect on the life expectancy of humans, and is found much more often in people living to 100 and beyond - moreover, this appears to be true worldwide

Biology

https://en.wikipedia.org/wiki?curid=21392296

Research into centenarians

Research into centenarians Some research suggests that centenarian offspring are more likely to age in better cardiovascular health than their peers. Several studies have shown that centenarians have better cardiovascular risk profiles compared to younger old people. The contribution of drug treatments to promote extreme longevity is not confirmed and centenarians in general have needed fewer drugs at younger ages due to a healthy lifestyle. A study by the International Longevity Centre-UK, published in 2011, suggested that today's centenarians may be healthier than the next generation of centenarians. Ninety percent of the centenarians studied in the New England Centenarian Study were functionally independent the vast majority of their lives up until the average age of 92 years and seventy-five percent were the same at an average age of 95 years. Similarly, a study of US supercentenarians (age 110 to 119 years) showed that, even at these advanced ages, 40% needed little assistance or were independent. A study supported by the US National Institute on Aging found significant associations between month of birth and longevity, with individuals born in September–November having a higher likelihood of becoming centenarians compared to March-born individuals. In the United States, a 2010 Census Bureau report found that more than 80 percent of centenarians are women.

Biology

https://en.wikipedia.org/wiki?curid=21392296

Research into centenarians

Phototaxis is a kind of taxis, or locomotory movement, that occurs when a whole organism moves towards or away from a stimulus of light. This is advantageous for phototrophic organisms as they can orient themselves most efficiently to receive light for photosynthesis. is called positive if the movement is in the direction of increasing light intensity and negative if the direction is opposite. Two types of positive phototaxis are observed in prokaryotes. The first is called scotophobotaxis (from the word "scotophobia"), which is observed only under a microscope. This occurs when a bacterium swims by chance out of the area illuminated by the microscope. Entering darkness signals the cell to reverse flagella rotation direction and reenter the light. The second type of phototaxis is true phototaxis, which is a directed movement up a gradient to an increasing amount of light. This is analogous to positive chemotaxis except that the attractant is light rather than a chemical. Phototactic responses are observed in many organisms such as "Serratia marcescens", "Tetrahymena", and "Euglena". Each organism has its own specific biological cause for a phototactic response, many of which are incidental and serve no end purpose. in zooplankton is well studied in the marine annelid "Platynereis dumerilii": "Platynereis dumerilii" trochophore and metatrochophore larvae are positively phototactic. there is mediated by simple eyespots that consists of a pigment cell and a photoreceptor cell

Biology

https://en.wikipedia.org/wiki?curid=21392957

Phototaxis

Phototaxis The photoreceptor cell synapses directly onto ciliated cells, which are used for swimming. The eyespots do not give spatial resolution, therefore the larvae are rotating to scan their environment for the direction where the light is coming from. "Platynereis dumerilii" nectochaete larvae can switch between positive and negative phototaxis. there is mediated by two pairs of more complex pigment cup eyes. These eyes contain more photoreceptor cells that are shaded by pigment cells forming a cup. The photoreceptor cells do not synapse directly onto ciliated cells or muscle cells but onto inter-neurons of a processing center. This way the information of all four eye cups can be compared and a low resolution image of four pixels can be created telling the larvae where the light is coming from. This way the larva does not need to scan its environment by rotating. This is an adaption for living on the bottom of the sea the life style of the nectochaete larva while scanning rotation is more suited for living in the open water column, the life style of the trochophore larva. in the "Platynereis dumerilii" nectochaete larva has a broad spectral range which is at least covered by three opsins that are expressed by the cup eyes: Two rhabdomeric opsins and a Go-opsin. However, not every behavior that looks like phototaxis is phototaxis: "Platynereis dumerilii" nechtochate and metatrochophore larvae swim up first when they are stimulated with UV-light from above

Biology

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Phototaxis

Phototaxis But after a while, they change the direction and avoid the UV-light by swimming down. This looks like a change from positive to negative phototaxis (see video left), but the larvae also swim down if UV-light comes non-directionally from the side. And so they do not swim to or away from the light, but swim down, this means to the center of gravity. Thus this is a UV-induced positive gravitaxis. Positive phototaxis (swimming to the light from the surface) and positive gravitaxis (swimming to the center of gravity) are induced by different ranges of wavelengths and cancel out each other at a certain ratio of wavelengths. Since the wavelengths compositions change in water with depth: Short (UV, violet) and long (red) wavelengths are lost first, phototaxis and gravitaxis form a ratio-chromatic depth gauge, which allows the larvae to determine their depth by the color of the surrounding water. This has the advantage over a brightness based depth gauge that the color stays almost constant independent of the time of the day or whether it is cloudy. Positive and negative phototaxis can be found in several species of jellyfish such as those from the genus Polyorchis. Jellyfish use ocelli to detect the presence and absence of light, which is then translated into anti-predatory behaviour in the case of a shadow being cast over the ocelli, or feeding behaviour in the case of the presence of light. Many tropical jellyfish have a symbiotic relationship with photosynthetic zooxanthellae that they harbor within their cells

Biology

https://en.wikipedia.org/wiki?curid=21392957

Phototaxis

Phototaxis The zooxanthellae nourish the jellyfish, while the jellyfish protects them, and moves them toward light sources such as the sun to maximize their light-exposure for efficient photosynthesis. In a shadow, the jellyfish can either remain still, or quickly move away in bursts to avoid predation and also re-adjust toward a new light source. This motor response to light and absence of light is facilitated by a chemical response from the ocelli, which results in a motor response causing the organism to swim toward a light source. Positive phototaxis can be found in many flying insects such as moths, grasshoppers, and flies. "Drosophila melanogaster" has been studied extensively for its innate positive phototactic response to light sources, using controlled experiments to help understand the connection between airborne locomotion toward a light source. This innate response is common among insects that fly primarily during the night utilizing transverse orientation vis-à-vis the light of the moon for orientation. Artificial lighting in cities and populated areas results in a more pronounced positive response compared to that with the distant light of the moon, resulting in the organism repeatedly responding to this new supernormal stimulus and innately flying toward it. Evidence for the innate response of positive phototaxis in "Drosophila melanogaster" was carried out by altering the wings of several individual specimens, both physically (via removal) and genetically (via mutation)

Biology

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Phototaxis

Phototaxis In both cases there was a noticeable lack of positive phototaxis, demonstrating that flying toward light sources is an innate response to the organisms' photoreceptors receiving a positive response. Negative phototaxis can be observed in larval "drosophila melanogaster" within the first three developmental instar stages, despite adult insects displaying positive phototaxis. This behaviour is common among other species of insects which possess a flightless larval and adult stage in their life cycles, only switching to positive phototaxis when searching for pupation sites. "Tenebrio molitor" by comparison is one species which carries its negative phototaxis into adulthood. Under experimental conditions organisms that use positive phototaxis have also shown correlation with light and magnetic fields. Under homogeneous light conditions with a shifting magnetic field, "Drosophila melanogaster" larvae reorient themselves toward predicted directions of greater or lesser light intensities as expected by a rotating magnetic field. In complete darkness, the larvae orient randomly without any notable preference. This suggests, the larvae can observe a visible pattern in combination with light.

Biology

https://en.wikipedia.org/wiki?curid=21392957

Phototaxis

Deep sea creature The term deep sea creature refers to organisms that live below the photic zone of the ocean. These creatures must survive in extremely harsh conditions, such as hundreds of bars of pressure, small amounts of oxygen, very little food, no sunlight, and constant, extreme cold. Most creatures have to depend on food floating down from above. These creatures live in very demanding environments, such as the abyssal or hadal zones, which, being thousands of meters below the surface, are almost completely devoid of light. The water is between 3 and 10 degrees Celsius and has low oxygen levels. Due to the depth, the pressure is between 20 and 1,000 bars. Creatures that live hundreds or even thousands of meters deep in the ocean have adapted to the high pressure, lack of light, and other factors. These animals have to survive the extreme pressure of the sub-photic zones. The pressure increases by about one bar every ten meters. To cope with the pressure, many fish are rather small. These creatures have also eliminated all excess cavities that would collapse under the pressure, such as swim bladders. The lack of light requires creatures to have special adaptations to find food, avoid predators, and find mates. Most animals have very large eyes with retinas constructed mainly of rods, which increases sensitivity. Many animals have also developed large feelers to replace peripheral vision. To be able to reproduce, many of these fish have evolved to be hermaphroditic, eliminating the need to find a mate

Biology

https://en.wikipedia.org/wiki?curid=21393008

Deep sea creature

Deep sea creature Many creatures have also developed a very strong sense of smell to detect the chemicals released by mates. At this depth, there is not enough light for photosynthesis to occur and not enough oxygen to support animals with a high metabolism. To survive, creatures have slower metabolisms which require less oxygen; they can live for long periods without food. Most food either comes from organic material that falls from above or from eating other creatures that have derived their food through the process of chemosynthesis (the process of changing chemical energy into food energy). Because of the sparse distributions of creatures, there is always at least some oxygen and food. Also, instead of using energy to search for food, these creatures use particular adaptations to ambush prey. Creatures that live in the sub-abyss require adaptations to cope with the naturally low oxygen levels. These adaptations range from chemotherapy, to the ever present self-inflating lungs. The term "deep-sea gigantism" describes an effect that living at such depths has on some creatures' sizes, especially relative to the size of relatives that live in different environments. These creatures are generally many times bigger than their counterparts. The giant isopod (related to the common pill bug) exemplifies this. To date, scientists have only been able to explain deep-sea gigantism in the case of the giant tube worm

Biology

https://en.wikipedia.org/wiki?curid=21393008

Deep sea creature

Deep sea creature Scientists believe these creatures are much larger than shallower-water tube worms because they live on hydrothermal vents that expel huge amounts of resources. They believe that, since the creatures don't have to expend energy regulating body temperature and have a smaller need for activity, they can allocate more resources to bodily processes. There are also cases of deep-sea creatures being abnormally small, such as the lantern shark, which fits in an adult human's mouth. Bioluminescence is the ability of an organism to create light through chemical reactions. Creatures use bioluminescence in many ways: to light their way, attract prey, or seduce a mate. Many underwater animals are bioluminescent—from the viper fish to the various species of flashlight fish, named for their light. Some creatures, such as the angler fish, have a concentration of photophores in a small limb that protrudes from their bodies, which they use as a lure to catch curious fish. Bioluminescence can also confuse enemies. The chemical process of bioluminescence requires at least two chemicals: the light producing chemical called luciferin and the reaction causing chemical called luciferase. The luciferase catalyzes the oxidation of the luciferin causing light and resulting in an inactive oxyluciferin. Fresh luciferin must be brought in through the diet or through internal synthesis

Biology

https://en.wikipedia.org/wiki?curid=21393008

Deep sea creature

Deep sea creature Since, at such deep levels, there is little to no sunlight, photosynthesis is not a possible means of energy production, leaving some creatures with the quandary of how to produce food for themselves. For the giant tube worm, this answer comes in the form of bacteria. These bacteria are capable of chemosynthesis and live inside the giant tube worm, which lives on hydrothermal vents. These vents spew forth very large amounts of chemicals, which these bacteria can transform into energy. These bacteria can also grow free of a host and create mats of bacteria on the sea floor around hydrothermal vents, where they serve as food for other creatures. Bacteria are a key energy source in the food chain. This source of energy creates large populations in areas around hydrothermal vents, which provides scientists with an easy stop for research. Organisms can also use chemosynthesis to attract prey or to attract a mate. Humans have explored less than 4% of the ocean floor, and dozens of new species of deep sea creatures are discovered with every dive. The submarine DSV Alvin—owned by the US Navy and operated by the Woods Hole Oceanographic Institution (WHOI) in Woods Hole, Massachusetts—exemplifies the type of craft used to explore deep water. This 16 ton submarine can withstand extreme pressure and is easily manoeuvrable despite its weight and size

Biology

https://en.wikipedia.org/wiki?curid=21393008

Deep sea creature

Deep sea creature The extreme difference in pressure between the sea floor and the surface makes the creature's survival on the surface near impossible; this makes in-depth research difficult because most useful information can only be found while the creatures are alive. Recent developments have allowed scientists to look at these creatures more closely, and for a longer time. A marine biologist, Jeffery Drazen, has explored a solution, a pressurized fish trap. This captures a deep-water creature, and adjusts its internal pressure slowly to surface level as the creature is brought to the surface, in the hope that the creature can adjust. Another scientific team, from the Universite Pierre et Marie Curie, has developed a capture device known as the PERISCOP, which maintains water pressure as it surfaces, thus keeping the samples in a pressurized environment during the ascent. This permits close study on the surface without any pressure disturbances affecting the sample.

Biology

https://en.wikipedia.org/wiki?curid=21393008

Deep sea creature

Microbiology (from Greek , "mīkros", "small"; , "bios", "life"; and , "-logia") is the study of microorganisms, those being unicellular (single cell), multicellular (cell colony), or acellular (lacking cells). encompasses numerous sub-disciplines including virology, bacteriology, protistology, mycology, immunology and parasitology. Eukaryotic microorganisms possess membrane-bound organelles and include fungi and protists, whereas prokaryotic organisms—all of which are microorganisms—are conventionally classified as lacking membrane-bound organelles and include Bacteria and Archaea. Microbiologists traditionally relied on culture, staining, and microscopy. However, less than 1% of the microorganisms present in common environments can be cultured in isolation using current means. Microbiologists often rely on molecular biology tools such as DNA sequence based identification, for example 16s rRNA gene sequence used for bacteria identification. Viruses have been variably classified as organisms, as they have been considered either as very simple microorganisms or very complex molecules. Prions, never considered as microorganisms, have been investigated by virologists, however, as the clinical effects traced to them were originally presumed due to chronic viral infections, and virologists took search—discovering "infectious proteins". The existence of microorganisms was predicted many centuries before they were first observed, for example by the Jains in India and by Marcus Terentius Varro in ancient Rome

Biology

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Microbiology

Microbiology The first recorded microscope observation was of the fruiting bodies of moulds, by Robert Hooke in 1666, but the Jesuit priest Athanasius Kircher was likely the first to see microbes, which he mentioned observing in milk and putrid material in 1658. Antonie van Leeuwenhoek is considered a father of microbiology as he observed and experimented with microscopic organisms in 1676, using simple microscopes of his own design. Scientific microbiology developed in the 19th century through the work of Louis Pasteur and in medical microbiology Robert Koch. The existence of microorganisms was hypothesized for many centuries before their actual discovery. The existence of unseen microbiological life was postulated by Jainism which is based on Mahavira’s teachings as early as 6th century BCE. Paul Dundas notes that Mahavira asserted the existence of unseen microbiological creatures living in earth, water, air and fire. Jain scriptures describe nigodas which are sub-microscopic creatures living in large clusters and having a very short life, said to pervade every part of the universe, even in tissues of plants and flesh of animals. The Roman Marcus Terentius Varro made references to microbes when he warned against locating a homestead in the vicinity of swamps "because there are bred certain minute creatures which cannot be seen by the eyes, which float in the air and enter the body through the mouth and nose and thereby cause serious diseases

Biology

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Microbiology

Microbiology " In the golden age of Islamic civilization, Iranian scientists hypothesized the existence of microorganisms, such as Avicenna in his book "The Canon of Medicine", Ibn Zuhr (also known as Avenzoar) who discovered scabies mites, and Al-Razi who gave the earliest known description of smallpox in his book "The Virtuous Life" (al-Hawi). In 1546, Girolamo Fracastoro proposed that epidemic diseases were caused by transferable seedlike entities that could transmit infection by direct or indirect contact, or vehicle transmission. In 1676, Antonie van Leeuwenhoek, who lived most of his life in Delft, Holland, observed bacteria and other microorganisms using a single-lens microscope of his own design. He is considered a father of microbiology as he pioneered the use of simple single-lensed microscopes of his own design. While Van Leeuwenhoek is often cited as the first to observe microbes, Robert Hooke made his first recorded microscopic observation, of the fruiting bodies of moulds, in 1665. It has, however, been suggested that a Jesuit priest called Athanasius Kircher was the first to observe microorganisms. Kircher was among the first to design magic lanterns for projection purposes, so he must have been well acquainted with the properties of lenses. He wrote "Concerning the wonderful structure of things in nature, investigated by Microscope" in 1646, stating "who would believe that vinegar and milk abound with an innumerable multitude of worms

Biology

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Microbiology

Microbiology " He also noted that putrid material is full of innumerable creeping animalcules. He published his "Scrutinium Pestis" (Examination of the Plague) in 1658, stating correctly that the disease was caused by microbes, though what he saw was most likely red or white blood cells rather than the plague agent itself. The field of bacteriology (later a subdiscipline of microbiology) was founded in the 19th century by Ferdinand Cohn, a botanist whose studies on algae and photosynthetic bacteria led him to describe several bacteria including "Bacillus" and "Beggiatoa". Cohn was also the first to formulate a scheme for the taxonomic classification of bacteria, and to discover endospores. Louis Pasteur and Robert Koch were contemporaries of Cohn, and are often considered to be the fathers of microbiology and medical microbiology, respectively. Pasteur is most famous for his series of experiments designed to disprove the then widely held theory of spontaneous generation, thereby solidifying microbiology's identity as a biological science. One of his students, Adrien Certes, is considered the founder of marine microbiology. Pasteur also designed methods for food preservation (pasteurization) and vaccines against several diseases such as anthrax, fowl cholera and rabies. Koch is best known for his contributions to the germ theory of disease, proving that specific diseases were caused by specific pathogenic microorganisms. He developed a series of criteria that have become known as the Koch's postulates

Biology

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Microbiology

Microbiology Koch was one of the first scientists to focus on the isolation of bacteria in pure culture resulting in his description of several novel bacteria including "Mycobacterium tuberculosis", the causative agent of tuberculosis. While Pasteur and Koch are often considered the founders of microbiology, their work did not accurately reflect the true diversity of the microbial world because of their exclusive focus on microorganisms having direct medical relevance. It was not until the late 19th century and the work of Martinus Beijerinck and Sergei Winogradsky that the true breadth of microbiology was revealed. Beijerinck made two major contributions to microbiology: the discovery of viruses and the development of enrichment culture techniques. While his work on the tobacco mosaic virus established the basic principles of virology, it was his development of enrichment culturing that had the most immediate impact on microbiology by allowing for the cultivation of a wide range of microbes with wildly different physiologies. Winogradsky was the first to develop the concept of chemolithotrophy and to thereby reveal the essential role played by microorganisms in geochemical processes. He was responsible for the first isolation and description of both nitrifying and nitrogen-fixing bacteria. French-Canadian microbiologist Felix d'Herelle co-discovered bacteriophages in 1917 and was one of the earliest applied microbiologists. Joseph Lister was the first to use phenol disinfectant on the open wounds of patients

Biology

https://en.wikipedia.org/wiki?curid=21393077

Microbiology

Microbiology The branches of microbiology can be classified into applied sciences, or divided according to taxonomy, as is the case with bacteriology, mycology, protozoology, virology and phycology. There is considerable overlap between the specific branches of microbiology with each other and with other disciplines, and certain aspects of these branches can extend beyond the traditional scope of microbiology A pure research branch of microbiology is termed cellular microbiology. While some fear microbes due to the association of some microbes with various human diseases, many microbes are also responsible for numerous beneficial processes such as industrial fermentation (e.g. the production of alcohol, vinegar and dairy products), antibiotic production and act as molecular vehicles to transfer DNA to complex organisms such as plants and animals. Scientists have also exploited their knowledge of microbes to produce biotechnologically important enzymes such as Taq polymerase, reporter genes for use in other genetic systems and novel molecular biology techniques such as the yeast two-hybrid system. Bacteria can be used for the industrial production of amino acids. "Corynebacterium glutamicum" is one of the most important bacterial species with an annual production of more than two million tons of amino acids, mainly L-glutamate and L-lysine. Since some bacteria have the ability to synthesize antibiotics, they are used for medicinal purposes, such as Streptomyces to make aminoglycoside antibiotics

Biology

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Microbiology

Microbiology A variety of biopolymers, such as polysaccharides, polyesters, and polyamides, are produced by microorganisms. Microorganisms are used for the biotechnological production of biopolymers with tailored properties suitable for high-value medical application such as tissue engineering and drug delivery. Microorganisms are for example used for the biosynthesis of xanthan, alginate, cellulose, cyanophycin, poly(gamma-glutamic acid), levan, hyaluronic acid, organic acids, oligosaccharides polysaccharide and polyhydroxyalkanoates. Microorganisms are beneficial for microbial biodegradation or bioremediation of domestic, agricultural and industrial wastes and subsurface pollution in soils, sediments and marine environments. The ability of each microorganism to degrade toxic waste depends on the nature of each contaminant. Since sites typically have multiple pollutant types, the most effective approach to microbial biodegradation is to use a mixture of bacterial and fungal species and strains, each specific to the biodegradation of one or more types of contaminants. Symbiotic microbial communities confer benefits to their human and animal hosts health including aiding digestion, producing beneficial vitamins and amino acids, and suppressing pathogenic microbes. Some benefit may be conferred by eating fermented foods, probiotics (bacteria potentially beneficial to the digestive system) or prebiotics (substances consumed to promote the growth of probiotic microorganisms)

Biology

https://en.wikipedia.org/wiki?curid=21393077

Microbiology

Microbiology The ways the microbiome influences human and animal health, as well as methods to influence the microbiome are active areas of research. Research has suggested that microorganisms could be useful in the treatment of cancer. Various strains of non-pathogenic clostridia can infiltrate and replicate within solid tumors. Clostridial vectors can be safely administered and their potential to deliver therapeutic proteins has been demonstrated in a variety of preclinical models.

Biology

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Microbiology

Scene statistics is a discipline within the field of perception. It is concerned with the statistical regularities related to scenes. It is based on the premise that a perceptual system is designed to interpret scenes. Biological perceptual systems have evolved in response to physical properties of natural environments. Therefore natural scenes receive a great deal of attention. Natural scene statistics are useful for defining the behavior of an ideal observer in a natural task, typically by incorporating signal detection theory, information theory, or estimation theory. One of the most successful applications of Natural Scenes Statistics Models has been perceptual picture and video quality prediction. For example, the Visual Information Fidelity (VIF) algorithm, which is used to measure the degree of distortion of pictures and videos, is used extensively by the image and video processing communities to assess perceptual quality, often after processing, such as compression, which can degrade the appearance of a visual signal. The premise is that the scene statistics are changed by distortion, and that the visual system is sensitive to the changes in the scene statistics. VIF is heavily used in the streaming television industry. Other popular picture quality models that use natural scene statistics include BRISQUE, and NIQE both of which are no-reference, since they do not require any reference picture to measure quality against

Biology

https://en.wikipedia.org/wiki?curid=21397214

Scene statistics

Scene statistics Geisler (2008) distinguishes between four kinds of domains: (1) Physical environments, (2) Images/Scenes, (3) Neural responses, and (4) Behavior. Within the domain of images/scenes, one can study the characteristics of information related to redundancy and efficient coding. Across-domain statistics determine how an autonomous system should make inferences about its environment, process information, and control its behavior. To study these statistics, it is necessary to sample or register information in multiple domains simultaneously.

Biology

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History of cell membrane theory Cell theory has its origins in seventeenth century microscopy observations, but it was nearly two hundred years before a complete cell membrane theory was developed to explain what separates cells from the outside world. By the 19th century it was accepted that some form of semi-permeable barrier must exist around a cell. Studies of the action of anesthetic molecules led to the theory that this barrier might be made of some sort of fat (lipid), but the structure was still unknown. A series of pioneering experiments in 1925 indicated that this barrier membrane consisted of two molecular layers of lipids—a lipid bilayer. New tools over the next few decades confirmed this theory, but controversy remained regarding the role of proteins in the cell membrane. Eventually the fluid mosaic model was composed in which proteins “float” in a fluid lipid bilayer "sea". Although simplistic and incomplete, this model is still widely referenced today. Since the invention of the microscope in the seventeenth century it has been known that plant and animal tissue is composed of cells : the cell was discovered by Robert Hooke. The plant cell wall was easily visible even with these early microscopes but no similar barrier was visible on animal cells, though it stood to reason that one must exist. By the mid 19th century, this question was being actively investigated and Moritz Traube noted that this outer layer must be semipermeable to allow transport of ions

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History of cell membrane theory

History of cell membrane theory Traube had no direct evidence for the composition of this film, though, and incorrectly asserted that it was formed by an interfacial reaction of the cell protoplasm with the extracellular fluid. The lipid nature of the cell membrane was first correctly intuited by Quincke, who noted that a cell generally forms a spherical shape in water and, when broken in half, forms two smaller spheres. The only other known material to exhibit this behavior was oil. He also noted that a thin film of oil behaves as a semipermeable membrane, precisely as predicted. Based on these observations, Quincke asserted that the cell membrane comprised a fluid layer of fat less than 100 nm thick. This theory was further extended by evidence from the study of anesthetics. Hans Horst Meyer and Ernest Overton independently noticed that the chemicals which act as general anesthetics are also those soluble in both water and oil. They interpreted this as meaning that to pass the cell membrane a molecule must be at least sparingly soluble in oil, their “lipoid theory of narcosis.” Based on this evidence and further experiments, they concluded that the cell membrane might be made of lecithin (phosphatidylcholine) and cholesterol. One of the early criticisms of this theory was that it included no mechanism for energy-dependent selective transport. This “flaw” remained unanswered for nearly half a century until the discovery that specialized molecules called integral membrane proteins can act as ion transportation pumps

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History of cell membrane theory

History of cell membrane theory Thus, by the early twentieth century the chemical, but not the structural nature of the cell membrane was known. Two experiments in 1924 laid the groundwork to fill in this gap. By measuring the capacitance of erythrocyte solutions Fricke determined that the cell membrane was 3.3 nm thick. Although the results of this experiment were accurate, Fricke misinterpreted the data to mean that the cell membrane is a single molecular layer. Because the polar lipid headgroups are fully hydrated, they do not show up in a capacitance measurement meaning that this experiment actually measured the thickness of the hydrocarbon core, not the whole bilayer. Gorter and Grendel approached the problem from a different perspective, performing a solvent extraction of erythrocyte lipids and spreading the resulting material as a monolayer on a Langmuir-Blodgett trough. When they compared the area of the monolayer to the surface area of the cells, they found a ratio of two to one. Later analyses of this experiment showed several problems including an incorrect monolayer pressure, incomplete lipid extraction and a miscalculation of cell surface area. In spite of these issues the fundamental conclusion- that the cell membrane is a lipid bilayer- was correct. A decade later, Davson and Danielli proposed a modification to this concept. In their model, the lipid bilayer was coated on either side with a layer of globular proteins

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History of cell membrane theory

History of cell membrane theory According to their view, this protein coat had no particular structure and was simply formed by adsorption from solution. Their theory was also incorrect in that it ascribed the barrier properties of the membrane to electrostatic repulsion from the protein layer rather than the energetic cost of crossing the hydrophobic core. A more direct investigation of the membrane was made possible through the use of electron microscopy in the late 1950s. After staining with heavy metal labels, Sjöstrand et al. noted two thin dark bands separated by a light region, which they incorrectly interpreted as a single molecular layer of protein. A more accurate interpretation was made by J. David Robertson, who determined that the dark electron-dense bands were the headgroups and associated proteins of two apposed lipid monolayers. In this body of work, Robertson put forward the concept of the “unit membrane.” This was the first time the bilayer structure had been universally assigned to all cell membranes as well as organelle membranes. The idea of a semipermeable membrane, a barrier that is permeable to solvent but impermeable to solute molecules was developed at about the same time. The term osmosis originated in 1827 and its importance to physiological phenomena realized, but it was not until 1877 when the botanist Wilhelm Pfeffer proposed the membrane theory of cell physiology

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History of cell membrane theory

History of cell membrane theory In this view, the cell was seen to be enclosed by a thin surface, the plasma membrane, and cell water and solutes such as a potassium ion existed in a physical state like that of a dilute solution. In 1889, Hamburger used hemolysis of erythrocytes to determine the permeability of various solutes. By measuring the time required for the cells to swell past their elastic limit, the rate at which solutes entered the cells could be estimated by the accompanying change in cell volume. He also found that there was an apparent nonsolvent volume of about 50% in red blood cells and later showed that this includes water of hydration in addition to the protein and other nonsolvent components of the cells. Ernest Overton (a distant cousin of Charles Darwin) first proposed the concept of a lipid (oil) plasma membrane in 1899. The major weakness of the lipid membrane was the lack of an explanation of the high permeability to water, so Nathansohn (1904) proposed the mosaic theory. In this view, the membrane is not a pure lipid layer, but a mosaic of areas with lipid and areas with semipermeable gel. Ruhland refined the mosaic theory to include pores to allow additional passage of small molecules. Since membranes are generally less permeable to anions, Leonor Michaelis concluded that ions are adsorbed to the walls of the pores, changing the permeability of the pores to ions by electrostatic repulsion

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History of cell membrane theory

History of cell membrane theory Michaelis demonstrated the membrane potential (1926) and proposed that it was related to the distribution of ions across the membrane. Harvey and James Danielli (1939) proposed a lipid bilayer membrane covered on each side with a layer of protein to account for measurements of surface tension. In 1941 Boyle & Conway showed that the membrane of resting frog muscle was permeable to both K+ and Cl-, but apparently not to Na+, so the idea of electrical charges in the pores was unnecessary since a single critical pore size explained the permeability to K+ , H+, and Cl- as well as the impermeability to Na+, Ca+, and Mg++. With the development of radioactive tracers, it was shown that cells are not impermeable to Na+. This was difficult to explain with the membrane barrier theory, so the sodium pump was proposed to continually remove Na+ as it permeates cells. This drove the concept that cells are in a state of dynamic equilibrium, constantly using energy to maintain ion gradients. In 1935, Karl Lohmann discovered ATP and its role as a source of energy for cells, so the concept of a metabolically-driven sodium pump was proposed. The tremendous success of Hodgkin, Huxley, and Katz in the development of the membrane theory of cellular membrane potentials, with differential equations that modeled the phenomena correctly, provided even more support for the membrane pump hypothesis. The modern view of the plasma membrane is of a fluid lipid bilayer that has protein components embedded within it

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History of cell membrane theory

History of cell membrane theory The structure of the membrane is now known in great detail, including 3D models of many of the hundreds of different proteins that are bound to the membrane. These major developments in cell physiology placed the membrane theory in a position of dominance. Around the same time the development of the first model membrane, the painted bilayer, allowed direct investigation of the properties of a simple artificial bilayer. By “painting” a reconstituted lipid solution across an aperture, Mueller and Rudin were able to determine that the resulting bilayer exhibited lateral fluidity, high electrical resistance and self-healing in response to puncture. This form of model bilayer soon became known as a “BLM” although from the beginning the meaning of this acronym has been ambiguous. As early as 1966, BLM was used to mean either “black lipid membrane” or "bimolecular lipid membrane". This same lateral fluidity was first demonstrated conclusively on the cell surface by Frye and Edidin in 1970. They fused two cells labeled with different membrane-bound fluorescent tags and watched as the two dye populations mixed. The results of this experiment were key in the development of the "fluid mosaic" model of the cell membrane by Singer and Nicolson in 1972. According to this model, biological membranes are composed largely of bare lipid bilayer with proteins penetrating either half way or all the way through the membrane. These proteins are visualized as freely floating within a completely liquid bilayer

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History of cell membrane theory

History of cell membrane theory This was not the first proposal of a heterogeneous membrane structure. Indeed, as early as 1904 Nathansohn proposed a “mosaic” of water permeable and impermeable regions. But the fluid mosaic model was the first to correctly incorporate fluidity, membrane channels and multiple modes of protein/bilayer coupling into one theory. Continued research has revealed some shortcomings and simplifications in the original theory. For instance, channel proteins are described as having a continuous water channel through their center, which is now known to be generally untrue (an exception being nuclear pore complexes, which have a 9 nm open water channel). Also, free diffusion on the cell surface is often limited to areas a few tens of nanometers across. These limits to lateral fluidity are due to cytoskeleton anchors, lipid phase separation and aggregated protein structures. Contemporary studies also indicate that much less of the plasma membrane is “bare” lipid than previously thought and in fact much of the cell surface may be protein-associated. In spite of these limitations, the fluid mosaic model remains a popular and often referenced general notion for the structure of biological membranes. The modern mainstream consensus model of cellular membranes is based on the fluid-mosaic model that envisions a lipid bilayer separating the inside from the outside of cells with associated ion channels, pumps and transporters giving rise to the permeability processes of cells

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History of cell membrane theory

History of cell membrane theory Alternative hypotheses were developed in the past that have largely been rejected. One of these opposing concepts developed early within the context of studies on osmosis, permeability, and electrical properties of cells was that of Gilbert Ling. The modern idea holds that these properties all belonged to the plasma membrane whereas Ling's view was that the protoplasm was responsible for these properties. As support for the lipid bilayer membrane theory grew, this alternative concept was developed which denied the importance of the lipid bilayer membrane. Procter & Wilson (1916) demonstrated that gels, which do not have a semipermeable membrane, swelled in dilute solutions. Loeb (1920) also studied gelatin extensively, with and without a membrane, showing that more of the properties attributed to the plasma membrane could be duplicated in gels without a membrane. In particular, he found that an electrical potential difference between the gelatin and the outside medium could be developed, based on the H+ concentration. Some criticisms of the membrane theory developed in the 1930s, based on observations such as the ability of some cells to swell and increase their surface area by a factor of 1000. A lipid layer cannot stretch to that extent without becoming a patchwork (thereby losing its barrier properties). Such criticisms stimulated continued studies on protoplasm as the principal agent determining cell permeability properties

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History of cell membrane theory

History of cell membrane theory In 1938, Fischer and Suer proposed that water in the protoplasm is not free but in a chemically combined form, and that the protoplasm represents a combination of protein, salt and water. They demonstrated the basic similarity between swelling in living tissues and the swelling of gelatin and fibrin gels. Dimitri Nasonov (1944) viewed proteins as the central components responsible for many properties of the cell, including electrical properties. By the 1940s, the bulk phase theories were not as well developed as the membrane theories and were largely rejected. In 1941, Brooks & Brooks published a monograph The Permeability of Living Cells, which rejects the bulk phase theories.

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History of cell membrane theory

Eidetic memory ( ; more commonly called photographic memory) is the ability to recall an image from memory with high precision for a brief period after seeing it only once, and without using a mnemonic device. Although the terms "eidetic memory" and "photographic memory" are popularly used interchangeably, they are also distinguished, with eidetic memory referring to the ability to view memories like photographs for a few minutes, and photographic memory referring to the ability to recall pages of text or numbers, or similar, in great detail. When the concepts are distinguished, eidetic memory is reported to occur in a small number of children and generally not found in adults, while true photographic memory has never been demonstrated to exist. The word "eidetic" comes from the Greek word εἶδος (, "eidos"). The terms "eidetic memory" and "photographic memory" are commonly used interchangeably, but they are also distinguished. Scholar Annette Kujawski Taylor stated, "In eidetic memory, a person has an almost faithful mental image snapshot or photograph of an event in their memory. However, eidetic memory is not limited to visual aspects of memory and includes auditory memories as well as various sensory aspects across a range of stimuli associated with a visual image." Author Andrew Hudmon commented: "Examples of people with a photographic-like memory are rare. Eidetic imagery is the ability to remember an image in so much detail, clarity, and accuracy that it is as though the image were still being perceived

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Eidetic memory

Eidetic memory It is not perfect, as it is subject to distortions and additions (like episodic memory), and vocalization interferes with the memory." "Eidetikers", as those who possess this ability are called, report a vivid afterimage that lingers in the visual field with their eyes appearing to scan across the image as it is described. Contrary to ordinary mental imagery, eidetic images are externally projected, experienced as "out there" rather than in the mind. Vividness and stability of the image begins to fade within minutes after the removal of the visual stimulus. Lilienfeld et al. stated, "People with eidetic memory can supposedly hold a visual image in their mind with such clarity that they can describe it perfectly or almost perfectly ..., just as we can describe the details of a painting immediately in front of us with near perfect accuracy." By contrast, photographic memory may be defined as the ability to recall pages of text, numbers, or similar, in great detail, without the visualization that comes with eidetic memory. It may be described as the ability to briefly look at a page of information and then recite it perfectly from memory. This type of ability has never been proven to exist and is considered popular myth. is typically found only in young children, as it is virtually nonexistent in adults. Hudmon stated, "Children possess far more capacity for eidetic imagery than adults, suggesting that a developmental change (such as acquiring language skills) may disrupt the potential for eidetic imagery

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Eidetic memory

Eidetic memory " has been found in 2 to 10 percent of children aged 6 to 12. It has been hypothesized that language acquisition and verbal skills allow older children to think more abstractly and thus rely less on visual memory systems. Extensive research has failed to demonstrate consistent correlations between the presence of eidetic imagery and any cognitive, intellectual, neurological or emotional measure. A few adults have had phenomenal memories (not necessarily of images), but their abilities are also unconnected with their intelligence levels and tend to be highly specialized. In extreme cases, like those of Solomon Shereshevsky and Kim Peek, memory skills can reportedly hinder social skills. Shereshevsky was a trained mnemonist, not an eidetic memoriser, and there are no studies that confirm whether Kim Peek had true eidetic memory. According to Herman Goldstine, the mathematician John von Neumann was able to recall from memory every book he had ever read. Scientific skepticism about the existence of eidetic memory was fueled around 1970 by Charles Stromeyer, who studied his future wife, Elizabeth, who claimed that she could recall poetry written in a foreign language that she did not understand years after she had first seen the poem. She also could, apparently, recall random dot patterns with such fidelity as to combine two patterns into a stereoscopic image. She remains the only person documented to have passed such a test

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Eidetic memory

Eidetic memory However, the methods used in the testing procedures could be considered questionable (especially given the extraordinary nature of the claims being made), as is the fact that the researcher married his subject. Additionally, that the tests have never been repeated (Elizabeth has consistently refused to repeat them) raises further concerns. Lilienfeld et al. stated: "Some psychologists believe that eidetic memory reflects an unusually long persistence of the iconic image in some lucky people". They added: "More recent evidence raises questions about whether any memories are truly photographic (Rothen, Meier & Ward, 2012). Eidetikers' memories are clearly remarkable, but they are rarely perfect. Their memories often contain minor errors, including information that was not present in the original visual stimulus. So even eidetic memory often appears to be reconstructive". The American cognitive scientist Marvin Minsky, in his book "The Society of Mind" (1988), considered reports of photographic memory to be an "unfounded myth." Furthermore, there is "no" scientific consensus regarding the nature, the proper definition, or even the very existence of eidetic imagery, even in children. Scientific skeptic author Brian Dunning reviewed the literature on the subject of both eidetic and photographic memory in 2016 and concluded that there is "a lack of compelling evidence that eidetic memory exists at all among healthy adults, and no evidence that photographic memory exists

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Eidetic memory

Eidetic memory But there's a common theme running through many of these research papers, and that's that the difference between ordinary memory and exceptional memory appears to be one of degree." To constitute photographic or eidetic memory, the visual recall must persist without the use of mnemonics, expert talent, or other cognitive strategies. Various cases have been reported that rely on such skills and are erroneously attributed to photographic memory. An example of extraordinary memory abilities being ascribed to eidetic memory comes from the popular interpretations of Adriaan de Groot's classic experiments into the ability of chess grandmasters to memorize complex positions of chess pieces on a chess board. Initially, it was found that these experts could recall surprising amounts of information, far more than nonexperts, suggesting eidetic skills. However, when the experts were presented with arrangements of chess pieces that could never occur in a game, their recall was no better than the nonexperts, suggesting that they had developed an ability to organize certain types of information, rather than possessing innate eidetic ability. Individuals identified as having a condition known as hyperthymesia are able to remember very intricate details of their own personal lives, but the ability seems not to extend to other, non-autobiographical information. They may have vivid recollections such as who they were with, what they were wearing, and how they were feeling on a specific date many years in the past

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Eidetic memory

Eidetic memory Patients under study, such as Jill Price, show brain scans that resemble those with obsessive–compulsive disorder. In fact, Price's unusual autobiographical memory has been attributed as a byproduct of compulsively making journal and diary entries. Hyperthymestic patients may additionally have depression stemming from the inability to forget unpleasant memories and experiences from the past. It is a misconception that hyperthymesia suggests any eidetic ability. Each year at the World Memory Championships, the world's best memorizers compete for prizes. None of the world's best competitive memorizers has a photographic memory, and no one with claimed eidetic or photographic memory has ever won the championship. With the questionable exception of Elizabeth Stromeyer, a 2006 article in "Slate" magazine claimed that, of the people rigorously scientifically tested, no one claiming to have long-term eidetic memory had this ability proven. There are a number of individuals whose extraordinary memory has been labeled "eidetic", but many use mnemonics and other, non-eidetic memory-enhancing exercises. Others have not been thoroughly tested.

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Eidetic memory

Qualia In philosophy and certain models of psychology, qualia ( or ; singular form: quale) are defined as individual instances of subjective, conscious experience. The term "qualia" derives from the Latin neuter plural form ("qualia") of the Latin adjective "quālis" () meaning "of what sort" or "of what kind" in a specific instance, such as "what it is like to taste a specific apple, this particular apple now". Examples of qualia include the perceived sensation of "pain" of a headache, the "taste" of wine, as well as the "redness" of an evening sky. As qualitative characters of sensation, qualia stand in contrast to "propositional attitudes", where the focus is on beliefs about experience rather than what it is directly like to be experiencing. Philosopher and cognitive scientist Daniel Dennett once suggested that "qualia" was "an unfamiliar term for something that could not be more familiar to each of us: the ways things seem to us". Much of the debate over their importance hinges on the definition of the term, and various philosophers emphasize or deny the existence of certain features of qualia. Consequently, the nature and existence of various definitions of qualia remain controversial because they are not verifiable. There are many definitions of qualia, which have changed over time. One of the simpler, broader definitions is: "The 'what it is like' character of mental states. The way it feels to have mental states such as pain, seeing red, smelling a rose, etc

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Qualia

Qualia " Charles Sanders Peirce introduced the term quale in philosophy in 1866. Clarence Irving Lewis, in his book "Mind and the World Order" (1929), was the first to use the term "qualia" in its generally agreed upon modern sense. Frank Jackson later defined qualia as "...certain features of the bodily sensations especially, but also of certain perceptual experiences, which no amount of purely physical information includes". Daniel Dennett identifies four properties that are commonly ascribed to qualia. According to these, qualia are: If qualia of this sort exist, then a normally sighted person who sees red would be unable to describe the experience of this perception in such a way that a listener who has never experienced color will be able to know everything there is to know about that experience. Though it is possible to make an analogy, such as "red looks hot", or to provide a description of the conditions under which the experience occurs, such as "it's the color you see when light of 700-nm wavelength is directed at you", supporters of this kind of qualia contend that such a description is incapable of providing a complete description of the experience. Another way of defining qualia is as "raw feels". A "raw feel" is a perception in and of itself, considered entirely in isolation from any effect it might have on behavior and behavioral disposition. In contrast, a "cooked feel" is that perception seen as existing in terms of its effects

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Qualia

Qualia For example, the perception of the taste of wine is an ineffable, raw feel, while the experience of warmth or bitterness caused by that taste of wine would be a cooked feel. Cooked feels are not qualia. According to an argument put forth by Saul Kripke in his paper "Identity and Necessity" (1971), one key consequence of the claim that such things as raw feels can be meaningfully discussed—that qualia exist—is that it leads to the logical possibility of two entities exhibiting identical behavior in all ways despite one of them entirely lacking qualia. While very few ever claim that such an entity, called a philosophical zombie, actually exists, the mere possibility is claimed to be sufficient to refute physicalism. Arguably, the idea of hedonistic utilitarianism, where the ethical value of things is determined from the amount of subjective pleasure or pain they cause, is dependent on the existence of qualia. Since it is by definition impossible to convey qualia verbally, it is also impossible to demonstrate them directly in an argument; so a more tangential approach is needed. Arguments for qualia generally come in the form of thought experiments designed to lead one to the conclusion that qualia exist. Although it does not actually mention the word "qualia", Thomas Nagel's paper "What Is it Like to Be a Bat?" is often cited in debates over qualia. Nagel argues that consciousness has an essentially subjective character, a what-it-is-like aspect

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Qualia

Qualia He states that "an organism has conscious mental states if and only if there is something that it is like to "be" that organism—something it is like "for" the organism." Nagel also suggests that the subjective aspect of the mind may not ever be sufficiently accounted for by the objective methods of reductionistic science. He claims that "if we acknowledge that a physical theory of mind must account for the subjective character of experience, we must admit that no presently available conception gives us a clue about how this could be done." Furthermore, he states that "it seems unlikely that any physical theory of mind can be contemplated until more thought has been given to the general problem of subjective and objective." The inverted spectrum thought experiment, originally developed by John Locke, invites us to imagine that we wake up one morning and find that for some unknown reason all the colors in the world have been inverted, i.e. swapped to the hue on the opposite side of a color wheel. Furthermore, we discover that no physical changes have occurred in our brains or bodies that would explain this phenomenon. Supporters of the existence of qualia argue that since we can imagine this happening without contradiction, it follows that we are imagining a change in a property that determines the way things look to us, but that has no physical basis. In more detail: The argument thus claims that if we find the inverted spectrum plausible, we must admit that qualia exist (and are non-physical)

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Qualia

Qualia Some philosophers find it absurd that an armchair argument can prove something to exist, and the detailed argument does involve a lot of assumptions about conceivability and possibility, which are open to criticism. Perhaps it is not possible for a given brain state to produce anything other than a given quale in our universe, and that is all that matters. The idea that an inverted spectrum would be undetectable in practice is also open to criticism on more scientific grounds (see main article). There is an actual experiment—albeit somewhat obscure—that parallels the inverted spectrum argument. George M. Stratton, professor of psychology at the University of California, Berkeley, performed an experiment in which he wore special prism glasses that caused the external world to appear upside down. After a few days of continually wearing the glasses, an adaptation occurred and the external world appeared righted. When the glasses were removed, the external world again appeared inverted. After a similar period, perception of the external world returned to the "normal" perceptual state. If this argument provides indicia that qualia exist, it does not necessarily follow that they must be non-physical, because that distinction should be considered a separate epistemological issue. A similar argument holds that it is conceivable (or not inconceivable) that there could be physical duplicates of people, called "philosophical zombies", without any qualia at all

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Qualia

Qualia These "zombies" would demonstrate outward behavior precisely similar to that of a normal human, but would not have a subjective phenomenology. It is worth noting that a necessary condition for the possibility of philosophical zombies is that there be no specific part or parts of the brain that directly give rise to qualia—the zombie can only exist if subjective consciousness is causally separate from the physical brain. "Are zombies possible? They're not just possible, they're actual. We're all zombies. Nobody is conscious." - Daniel Dennett ("Consciousness Explained,1991") Joseph Levine's paper "Conceivability, Identity, and the Explanatory Gap" takes up where the criticisms of conceivability arguments, such as the inverted spectrum argument and the zombie argument, leave off. Levine agrees that conceivability is flawed as a means of establishing metaphysical realities, but points out that even if we come to the "metaphysical" conclusion that qualia are physical, there is still an "explanatory" problem. However, such an epistemological or explanatory problem might indicate an underlying metaphysical issue—the non-physicality of qualia, even if not proven by conceivability arguments is far from ruled out. Frank Jackson offers what he calls the "knowledge argument" for qualia. One example runs as follows: This thought experiment has two purposes. First, it is intended to show that qualia exist

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Qualia

Qualia If one agrees with the thought experiment, we believe that Mary gains something after she leaves the room—that she acquires knowledge of a particular thing that she did not possess before. That knowledge, Jackson argues, is knowledge of the quale that corresponds to the experience of seeing red, and it must thus be conceded that qualia are real properties, since there is a difference between a person who has access to a particular quale and one who does not. The second purpose of this argument is to refute the physicalist account of the mind. Specifically, the knowledge argument is an attack on the physicalist claim about the completeness of physical truths. The challenge posed to physicalism by the knowledge argument runs as follows: First Jackson argued that qualia are epiphenomenal: not causally efficacious with respect to the physical world. Jackson does not give a positive justification for this claim—rather, he seems to assert it simply because it defends qualia against the classic problem of dualism. Our natural assumption would be that qualia must be causally efficacious in the physical world, but some would ask how we could argue for their existence if they did not affect our brains. If qualia are to be non-physical properties (which they must be in order to constitute an argument against physicalism), some argue that it is almost impossible to imagine how they could have a causal effect on the physical world

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Qualia

Qualia By redefining qualia as epiphenomenal, Jackson attempts to protect them from the demand of playing a causal role. Later, however, he rejected epiphenomenalism. This, he argues, is because when Mary first sees red, she says "wow", so it must be Mary's qualia that cause her to say "wow". This contradicts epiphenomenalism. Since the Mary's room thought experiment seems to create this contradiction, there must be something wrong with it. This is often referred to as the "there must be a reply" reply. In "Consciousness Explained" (1991) and "Quining Qualia" (1988), Daniel Dennett offers an argument against qualia by claiming that the above definition breaks down when one tries to make a practical application of it. In a series of thought experiments, which he calls "intuition pumps", he brings qualia into the world of neurosurgery, clinical psychology, and psychological experimentation. His argument states that, once the concept of qualia is so imported, it turns out that we can either make no use of it in the situation in question, or that the questions posed by the introduction of qualia are unanswerable precisely because of the special properties defined for qualia. In Dennett's updated version of the inverted spectrum thought experiment, "alternative neurosurgery", you again awake to find that your qualia have been inverted—grass appears red, the sky appears orange, etc. According to the original account, you should be immediately aware that something has gone horribly wrong

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Qualia

Qualia Dennett argues, however, that it is impossible to know whether the diabolical neurosurgeons have indeed inverted your qualia (by tampering with your optic nerve, say), or have simply inverted your connection to memories of past qualia. Since both operations would produce the same result, you would have no means on your own to tell which operation has actually been conducted, and you are thus in the odd position of not knowing whether there has been a change in your "immediately apprehensible" qualia. Dennett's argument revolves around the central objection that, for qualia to be taken seriously as a component of experience—for them to even make sense as a discrete concept—it must be possible to show that Dennett attempts to show that we cannot satisfy (a) either through introspection or through observation, and that qualia's very definition undermines its chances of satisfying (b). Supporters of qualia could point out that in order for you to notice a change in qualia, you must compare your current qualia with your memories of past qualia. Arguably, such a comparison would involve immediate apprehension of your current qualia "and" your memories of past qualia, but not the past qualia "themselves". Furthermore, modern functional brain imaging has increasingly suggested that the memory of an experience is processed in similar ways and in similar zones of the brain as those originally involved in the original perception

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Qualia

Qualia This may mean that there would be asymmetry in outcomes between altering the mechanism of perception of qualia and altering their memories. If the diabolical neurosurgery altered the immediate perception of qualia, you might not even notice the inversion directly, since the brain zones which re-process the memories would themselves invert the qualia remembered. On the other hand, alteration of the qualia memories themselves would be processed without inversion, and thus you would perceive them as an inversion. Thus, you might know immediately if memory of your qualia had been altered, but might not know if immediate qualia were inverted or whether the diabolical neurosurgeons had done a sham procedure. Dennett also has a response to the "Mary the color scientist" thought experiment. He argues that Mary would not, in fact, learn something new if she stepped out of her black and white room to see the color red. Dennett asserts that if she already truly knew "everything about color", that knowledge would include a deep understanding of why and how human neurology causes us to sense the "quale" of color. Mary would therefore already know exactly what to expect of seeing red, before ever leaving the room. Dennett argues that the misleading aspect of the story is that Mary is supposed to not merely be knowledgeable about color but to actually know "all" the physical facts about it, which would be a knowledge so deep that it exceeds what can be imagined, and twists our intuitions

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Qualia If Mary really does know everything physical there is to know about the experience of color, then this effectively grants her almost omniscient powers of knowledge. Using this, she will be able to deduce her own reaction, and figure out exactly what the experience of seeing red will feel like. Dennett finds that many people find it difficult to see this, so he uses the case of RoboMary to further illustrate what it would be like for Mary to possess such a vast knowledge of the physical workings of the human brain and color vision. RoboMary is an intelligent robot who, instead of the ordinary color camera-eyes, has a software lock such that she is only able to perceive black and white and shades in-between. RoboMary can examine the computer brain of similar non-color-locked robots when they look at a red tomato, and see exactly how they react and what kinds of impulses occur. RoboMary can also construct a simulation of her own brain, unlock the simulation's color-lock and, with reference to the other robots, simulate exactly how this simulation of herself reacts to seeing a red tomato. RoboMary naturally has control over all of her internal states except for the color-lock. With the knowledge of her simulation's internal states upon seeing a red tomato, RoboMary can put her own internal states directly into the states they would be in upon seeing a red tomato. In this way, without ever seeing a red tomato through her cameras, she will know exactly what it is like to see a red tomato

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Qualia Dennett uses this example to show us that Mary's all-encompassing physical knowledge makes her own internal states as transparent as those of a robot or computer, and it is almost straightforward for her to figure out exactly how it feels to see red. Perhaps Mary's failure to learn exactly what seeing red feels like is simply a failure of language, or a failure of our ability to describe experiences. An alien race with a different method of communication or description might be perfectly able to teach their version of Mary exactly how seeing the color red would feel. Perhaps it is simply a uniquely human failing to communicate first-person experiences from a third-person perspective. Dennett suggests that the description might even be possible using English. He uses a simpler version of the Mary thought experiment to show how this might work. What if Mary was in a room without triangles and was prevented from seeing or making any triangles? An English-language description of just a few words would be sufficient for her to imagine what it is like to see a triangle—she can simply and directly visualize a triangle in her mind. Similarly, Dennett proposes, it is perfectly, logically possible that the quale of what it is like to see red could eventually be described in an English-language description of millions or billions of words

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Qualia In "Are we explaining consciousness yet?" (2001), Dennett approves of an account of qualia defined as the deep, rich collection of individual neural responses that are too fine-grained for language to capture. For instance, a person might have an alarming reaction to yellow because of a yellow car that hit her previously, and someone else might have a nostalgic reaction to a comfort food. These effects are too individual-specific to be captured by English words. "If one dubs this inevitable residue "qualia", then qualia are guaranteed to exist, but they are just more of the same, dispositional properties that have not yet been entered in the catalog [...]." According to Paul Churchland, Mary might be considered to be like a feral child. Feral children have suffered extreme isolation during childhood. Technically when Mary leaves the room, she would not have the ability to see or know what the color red is. A brain has to learn and develop how to see colors. Patterns need to form in the V4 section of the visual cortex. These patterns are formed from exposure to wavelengths of light. This exposure is needed during the early stages of brain development. In Mary's case, the identifications and categorizations of color will only be in respect to representations of black and white. In his book "Good and Real" (2006), Gary Drescher compares qualia with "gensyms" (generated symbols) in Common Lisp

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Qualia These are objects that Lisp treats as having no properties or components and which can only be identified as equal or not equal to other objects. Drescher explains, "we have no introspective access to whatever internal properties make the "red" gensym recognizably distinct from the "green" [...] even though we know the sensation when we experience it." Under this interpretation of qualia, Drescher responds to the Mary thought experiment by noting that "knowing about red-related cognitive structures and the dispositions they engender—even if that knowledge were implausibly detailed and exhaustive—would not necessarily give someone who lacks prior color-experience the slightest clue whether the card now being shown is of the color called red." This does not, however, imply that our experience of red is non-mechanical; "on the contrary, gensyms are a routine feature of computer-programming languages". David Lewis has an argument that introduces a new hypothesis about types of knowledge and their transmission in qualia cases. Lewis agrees that Mary cannot learn what red looks like through her monochrome physicalist studies. But he proposes that this doesn't matter. Learning transmits information, but experiencing qualia doesn't transmit information; instead it communicates abilities. When Mary sees red, she doesn't get any new information. She gains new abilities—now she can remember what red looks like, imagine what other red things might look like and recognize further instances of redness

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Qualia Lewis states that Jackson's thought experiment uses the "Phenomenal Information Hypothesis"—that is, the new knowledge that Mary gains upon seeing red is phenomenal information. Lewis then proposes a different "Ability Hypothesis" that differentiates between two types of knowledge: knowledge that (information) and knowledge how (abilities). Normally the two are entangled; ordinary learning is also an experience of the subject concerned, and people both learn information (for instance, that Freud was a psychologist) and gain ability (to recognize images of Freud). However, in the thought experiment, Mary can only use ordinary learning to gain know-that knowledge. She is prevented from using experience to gain the know-how knowledge that would allow her to remember, imagine and recognize the color red. We have the intuition that Mary has been deprived of some vital data to do with the experience of redness. It is also uncontroversial that some things cannot be learned inside the room; for example, we do not expect Mary to learn how to ski within the room. Lewis has articulated that information and ability are potentially different things. In this way, physicalism is still compatible with the conclusion that Mary gains new knowledge. It is also useful for considering other instances of qualia; "being a bat" is an ability, so it is know-how knowledge

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Qualia The artificial intelligence researcher Marvin Minsky thinks the problems posed by qualia are essentially issues of complexity, or rather of mistaking complexity for simplicity. Michael Tye holds the opinion there are no qualia, no "veils of perception" between us and the referents of our thought. He describes our experience of an object in the world as "transparent". By this he means that no matter what private understandings and/or misunderstandings we may have of some public entity, it is still there before us in reality. The idea that qualia intervene between ourselves and their origins he regards as "a massive error"; as he says, "it is just not credible that visual experiences are systematically misleading in this way"; "the only objects of which you are aware are the external ones making up the scene before your eyes"; there are "no such things as the qualities of experiences" for "they are qualities of external surfaces (and volumes and films) if they are qualities of anything." This insistence permits him to take our experience as having a reliable base since there is no fear of losing contact with the realness of public objects. In Tye's thought there is no question of qualia without information being contained within them; it is always "an awareness that", always "representational". He characterizes the perception of children as a misperception of referents that are undoubtedly as present for them as they are for grown-ups

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Qualia As he puts it, they may not know that "the house is dilapidated", but there is no doubt about their seeing the house. After-images are dismissed as presenting no problem for the Transparency Theory because, as he puts it, after-images being illusory, there is nothing that one sees. Tye proposes that phenomenal experience has five basic elements, for which he has coined the acronym PANIC—Poised, Abstract, Nonconceptual, Intentional Content. It is "Poised" in the sense that the phenomenal experience is always presented to the understanding, whether or not the agent is able to apply a concept to it. Tye adds that the experience is "maplike" in that, in most cases, it reaches through to the distribution of shapes, edges, volumes, etc. in the world—you may not be reading the "map" but, as with an actual map there is a reliable match with what it is mapping. It is "Abstract" because it is still an open question in a particular case whether you are in touch with a concrete object (someone may feel a pain in a "left leg" when that leg has actually been amputated). It is "Nonconceptual" because a phenomenon can exist although one does not have the concept by which to recognize it. Nevertheless, it is "Intentional" in the sense that it represents something, again whether or not the particular observer is taking advantage of that fact; this is why Tye calls his theory "representationalism"

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Qualia This last makes it plain that Tye believes that he has retained a direct contact with what produces the phenomena and is therefore not hampered by any trace of a "veil of perception". Roger Scruton, whilst sceptical of the idea that neurobiology can tell us a great amount about consciousness, is of the opinion that the idea of qualia is incoherent, and that Wittgenstein's famous private language argument effectively disproves it. Scruton writes, The belief that these essentially private features of mental states exist, and that they form the introspectible essence of whatever possesses them, is grounded in a confusion, one that Wittgenstein tried to sweep away in his arguments against the possibility of a private language. When you judge that I am in pain, it is on the basis of my circumstances and behavior, and you could be wrong. When I ascribe a pain to myself, I don’t use any such evidence. I don’t find out that I am in pain by observation, nor can I be wrong. But that is not because there is some other fact about my pain, accessible only to me, which I consult in order to establish what I am feeling. For if there were this inner private quality, I could misperceive it; I could get it wrong, and I would have to find out whether I am in pain. To describe my inner state, I would also have to invent a language, intelligible only to me – and that, Wittgenstein plausibly argues, is impossible. The conclusion to draw is that I ascribe pain to myself not on the basis of some inner quale but on no basis at all

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Qualia In his book "On Human Nature", Scruton does pose a potential line of criticism to this, which is that whilst Wittgenstein's private language argument does disprove the concept of reference to qualia, or the idea that we can talk even to ourselves of their nature, it does not disprove its existence altogether. Scruton believes that this is a valid criticism, and this is why he stops short of actually saying that quales don't exist, and instead merely suggests that we should abandon them as a concept. However, he does give a quote by Wittgenstein as a response: "Whereof one cannot speak, thereof one must be silent." David Chalmers formulated the hard problem of consciousness, raising the issue of qualia to a new level of importance and acceptance in the field. In his paper "Absent Qualia, Fading Qualia, Dancing Qualia", he also argued for what he called "the principle of organizational invariance". In this paper, he argues that if a system such as one of appropriately configured computer chips reproduces the functional organization of the brain, it will also reproduce the qualia associated with the brain. E. J. Lowe, of Durham University, denies that holding to indirect realism (in which we have access only to sensory features internal to the brain) necessarily implies a Cartesian dualism. He agrees with Bertrand Russell that our "retinal images"—that is, the distributions across our retinas—are connected to "patterns of neural activity in the cortex" (Lowe 1986)

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Qualia He defends a version of the Causal Theory of Perception in which a causal path can be traced between the external object and the perception of it. He is careful to deny that we do any inferring from the sensory field, a view which he believes allows us to found an access to knowledge on that causal connection. In a later work he moves closer to the non-epistemic theory in that he postulates "a wholly non-conceptual component of perceptual experience", but he refrains from analyzing the relation between the perceptual and the "non-conceptual". Most recently he has drawn attention to the problems that hallucination raises for the direct realist and to their disinclination to enter the discussion on the topic. John Barry Maund, an Australian philosopher of perception at the University of Western Australia, draws attention to a key distinction of qualia. are open to being described on two levels, a fact that he refers to as "dual coding". Using the Television Analogy (which, as the non-epistemic argument shows, can be shorn of its objectionable aspects), he points out that, if asked what we see on a television screen there are two answers that we might give: The states of the screen during a football match are unquestionably different from those of the screen during a chess game, but there is no way available to us of describing the ways in which they are different except by reference to the play, moves and pieces in each game

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Qualia He has refined the explanation by shifting to the example of a "Movitype" screen, often used for advertisements and announcements in public places. A Movitype screen consists of a matrix—or "raster" as the neuroscientists prefer to call it (from the Latin "rastrum", a "rake"; think of the lines on a TV screen as "raked" across)—that is made up of an array of tiny light-sources. A computer-led input can excite these lights so as to give the impression of letters passing from right to left, or even, on the more advanced forms now commonly used in advertisements, to show moving pictures. Maund's point is as follows. It is obvious that there are two ways of describing what you are seeing. We could either adopt the everyday public language and say "I saw some sentences, followed by a picture of a 7-Up can." Although that is a perfectly adequate way of describing the sight, nevertheless, there is a scientific way of describing it which bears no relation whatsoever to this commonsense description. One could ask the electronics engineer to provide us with a computer print-out staged across the seconds that you were watching it of the point-states of the raster of lights. This would no doubt be a long and complex document, with the state of each tiny light-source given its place in the sequence

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Qualia The interesting aspect of this list is that, although it would give a comprehensive and point-by-point-detailed description of the state of the screen, nowhere in that list would there be a mention of "English sentences" or "a 7-Up can". What this makes clear is that there are two ways to describe such a screen, (1) the "commonsense" one, in which publicly recognizable objects are mentioned, and (2) an accurate point-by-point account of the actual state of the field, but makes no mention of what any passer-by would or would not make of it. This second description would be non-epistemic from the common sense point of view, since no objects are mentioned in the print-out, but perfectly acceptable from the engineer's point of view. Note that, if one carries this analysis across to human sensing and perceiving, this rules out Daniel Dennett's claim that all qualiaphiles must regard qualia as "ineffable", for at this second level they are in principle quite "effable"—indeed, it is not ruled out that some neurophysiologist of the future might be able to describe the neural detail of qualia at this level. Maund has also extended his argument particularly with reference of color. Color he sees as a dispositional property, not an objective one, an approach which allows for the facts of difference between person and person, and also leaves aside the claim that external objects are colored

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Qualia Colors are therefore "virtual properties", in that it is as if things possessed them; although the naïve view attributes them to objects, they are intrinsic, non-relational inner experiences. In his book "Sensing the World", Moreland Perkins argues that qualia need not be identified with their objective sources: a smell, for instance, bears no direct resemblance to the molecular shape that gives rise to it, nor is a toothache actually in the tooth. He is also like Hobbes in being able to view the process of sensing as being something complete in itself; as he puts it, it is not like "kicking a football" where an external object is required—it is more like "kicking a kick", an explanation which entirely avoids the familiar Homunculus Objection, as adhered to, for example, by Gilbert Ryle. Ryle was quite unable even to entertain this possibility, protesting that "in effect it explained the having of sensations as the not having of sensations." However, A.J. Ayer in a rejoinder identified this objection as "very weak" as it betrayed an inability to detach the notion of eyes, indeed any sensory organ, from the neural sensory experience. Vilayanur S

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Qualia Ramachandran and William Hirstein proposed three laws of qualia (with a fourth later added), which are "functional criteria that need to be fulfilled in order for certain neural events to be associated with qualia" by philosophers of the mind: They proposed that the phenomenal nature of qualia could be communicated (as in "oh "that" is what salt tastes like") if brains could be appropriately connected with a "cable of neurons". If this turned out to be possible this would scientifically prove or objectively demonstrate the existence and the nature of qualia. Howard Robinson is a philosopher who has concentrated his research within the philosophy of mind. Taking what has been through the latter part of the last century an unfashionable stance, he has consistently argued against those explanations of sensory experience that would reduce them to physical origins. He has never regarded the theory of sense-data as refuted, but has set out to refute in turn the objections which so many have considered to be conclusive. The version of the theory of sense-data he defends takes what is before consciousness in perception to be qualia as mental presentations that are causally linked to external entities, but which are not physical in themselves. Unlike the philosophers so far mentioned, he is therefore a dualist, one who takes both matter and mind to have real and metaphysically distinct natures

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Qualia In one of his most recent articles he takes the physicalist to task for ignoring the fact that sensory experience can be entirely free of representational character. He cites phosphenes as a stubborn example (phosphenes are flashes of neural light that result either from sudden pressure in the brain—as induced, for example, by intense coughing, or through direct physical pressure on the retina), and points out that it is grossly counter-intuitive to argue that these are not visual experiences on a par with open-eye seeing. William Robinson (no relation) takes a very similar view to that of his namesake. In his most recent book, "Understanding Phenomenal Consciousness", he is unusual as a dualist in calling for research programs that investigate the relation of qualia to the brain. The problem is so stubborn, he says, that too many philosophers would prefer "to explain it away", but he would rather have it explained and does not see why the effort should not be made. However, he does not expect there to be a straightforward scientific reduction of phenomenal experience to neural architecture; on the contrary he regards this as a forlorn hope. The "Qualitative Event Realism" that Robinson espouses sees phenomenal consciousness as caused by brain events but not identical with them, being non-material events

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Qualia It is noteworthy that he refuses to set aside the vividness—and commonness—of mental images, both visual and aural, standing here in direct opposition to Daniel Dennett, who has difficulty in crediting the experience in others. He is similar to Moreland Perkins in keeping his investigation wide enough to apply to all the senses. Edmond Wright is a philosopher who considers the intersubjective aspect of perception. From Locke onwards it had been normal to frame perception problems in terms of a single subject S looking at a single entity E with a property p. However, if we begin with the facts of the differences in sensory registration from person to person, coupled with the differences in the criteria we have learned for distinguishing what we together call "the same" things, then a problem arises of how two persons align their differences on these two levels so that they can still get a practical overlap on parts of the real about them—and, in particular, update each other about them. Wright mentions being struck with the hearing difference between himself and his son, discovering that his son could hear sounds up to nearly 20 kilohertz while his range only reached to 14 kHz or so. This implies that a difference in qualia could emerge in human action (for example, the son could warn the father of a high-pitched escape of a dangerous gas kept under pressure, the sound-waves of which would be producing no qualia evidence at all for the father)

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Qualia The relevance for language thus becomes critical, for an informative statement can best be understood as an updating of a perception—and this may involve a radical re-selection from the qualia fields viewed as non-epistemic, even perhaps of the presumed singularity of "the" referent, a fortiori if that "referent" is the self. Here he distinguishes his view from that of Revonsuo, who too readily makes his "virtual space" "egocentric". Wright's particular emphasis has been on what he asserts is a core feature of communication, that, in order for an updating to be set up and made possible, both speaker and hearer have to behave as if they have identified "the same singular thing", which, he notes, partakes of the structure of a joke or a story. Wright says that this systematic ambiguity seems to opponents of qualia to be a sign of fallacy in the argument (as ambiguity is in pure logic) whereas, on the contrary, it is sign—in talk about "what" is perceived—of something those speaking to each other have to learn to take advantage of. In extending this analysis, he has been led to argue for an important feature of human communication being the degree and character of the faith maintained by the participants in the dialogue, a faith that has priority over what has before been taken to be the key virtues of language, such as "sincerity", "truth", and "objectivity". Indeed, he considers that to prioritize them over faith is to move into superstition

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Qualia Erwin Schrödinger, a theoretical physicist and one of the leading pioneers of quantum mechanics, also published in the areas of colorimetry and color perception. In several of his philosophical writings, he defends the notion that qualia are not physical. He continues on to remark that subjective experiences do not form a one-to-one correspondence with stimuli. For example, light of wavelength in the neighborhood of 590 nm produces the sensation of yellow, whereas exactly the same sensation is produced by mixing red light, with wavelength 760 nm, with green light, at 535 nm. From this he concludes that there is no "numerical connection with these physical, objective characteristics of the waves" and the sensations they produce. Schrödinger concludes with a proposal of how it is that we might arrive at the mistaken belief that a satisfactory theoretical account of qualitative experience has been—or might ever be—achieved: When looked at philosophically, qualia become a tipping point between physicality and the metaphysical, which polarizes the discussion, as we've seen above, into "Do they or do they not exist?" and "Are they physical or beyond the physical?" However, from a strictly neurological perspective, they can both exist, and be very important to the organism's survival, and be the result of strict neuronal oscillation, and still not rule out the metaphysical. A good example of this pro/con blending is in Rodolfo Llinás's "I of the Vortex" (MIT Press, 2002, pp. 202–207)

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Qualia Llinás argues that qualia are ancient and necessary for an organism's survival "and" a product of neuronal oscillation. Llinás gives the evidence of anesthesia of the brain and subsequent stimulation of limbs to demonstrate that qualia can be "turned off" with changing only the variable of neuronal oscillation (local brain electrical activity), while all other connections remain intact, arguing strongly for an oscillatory—electrical origin of qualia, or important aspects of them. Roger Orpwood, an engineer with a strong background in studying neural mechanisms, proposed a neurobiological model that gives rise to qualia and ultimately, consciousness. As advancements in cognitive and computational neuroscience continue to grow, the need to study the mind, and qualia, from a scientific perspective follows. Orpwood does not deny the existence of qualia, nor does he intend to debate its physical or non-physical existence. Rather, he suggests that qualia are created through the neurobiological mechanism of re-entrant feedback in cortical systems Orpwood develops his mechanism by first addressing the issue of information. One unsolved aspect of qualia is the concept of the fundamental information involved in creating the experience. He does not address a position on the metaphysics of the information underlying the experience of qualia, nor does he state what information actually is. However, Orpwood does suggest that information in general is of two types: the information structure and information message

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Qualia Information structures are defined by the physical vehicles and structural, biological patterns encoding information. That encoded information is the information message; a source describing "what" that information is. The neural mechanism or network receives input information structures, completes a designated instructional task (firing of the neuron or network), and outputs a modified information structure to downstream regions. The information message is the purpose and meaning of the information structure and causally exists as a result of that particular information structure. Modification of the information structure changes the meaning of the information message, but the message itself cannot be directly altered. Local cortical networks have the capacity to receive feedback from their own output information structures. This form of local feedback continuously cycles part of the networks output structures as its next input information structure. Since the output structure must represent the information message derived from the input structure, each consecutive cycle that is fed-back will represent the output structure the network just generated. As the network of mechanisms cannot recognize the information message, but only the input information structure, the network is unaware that it is representing its own previous outputs. The neural mechanisms are merely completing their instructional tasks and outputting any recognizable information structures

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Qualia Orpwood proposes that these local networks come into an attractor state that consistently outputs exactly the same information structure as the input structure. Instead of only representing the information message derived from the input structure, the network will now represent its own output and thereby its own information message. As the input structures are fed-back, the network identifies the previous information structure as being a previous representation of the information message. As Orpwood states, Representation of the networks own output structures, by which represents its own information message, is Orpwood's explanation that grounds the manifestation of qualia via neurobiological mechanisms. These mechanisms are particular to networks of pyramidal neurons. Although computational neuroscience still has much to investigate regarding pyramidal neurons, their complex circuitry is relatively unique. Research shows that the complexity of pyramidal neuron networks is directly related to the increase in the functional capabilities of a species. When human pyramidal networks are compared with other primate species and species with less intricate behavioral and social interactions, the complexity of these neural networks drastically decline. The complexity of these networks are also increased in frontal brain regions. These regions are often associated with conscious assessment and modification of one's immediate environment; often referred to as "executive functions"

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Qualia Sensory input is necessary to gain information from the environment, and perception of that input is necessary for navigating and modifying interactions with the environment. This suggests that frontal regions containing more complex pyramidal networks are associated with an increased perceptive capacity. As perception is necessary for conscious thought to occur, and since the experience of qualia is derived from consciously recognizing some perception, qualia may indeed be specific to the functional capacity of pyramidal networks. This derives Orpwood's notion that the mechanisms of re-entrant feedback may not only create qualia, but also be the foundation to consciousness. It is possible to apply a criticism similar to Nietzsche's criticism of Kant's "thing in itself" to qualia: are unobservable in others and unquantifiable in us. We cannot possibly be sure, when discussing individual qualia, that we are even discussing the same phenomena. Thus, any discussion of them is of indeterminate value, as descriptions of qualia are necessarily of indeterminate accuracy. can be compared to "things in themselves" in that they have no publicly demonstrable properties; this, along with the impossibility of being sure that we are communicating about the same qualia, makes them of indeterminate value and definition in any philosophy in which proof relies upon precise definition. On the other hand, qualia could be considered akin to Kantian phenomena since they are held to be seemings of appearances

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Qualia Revonsuo, however, considers that, within neurophysiological inquiry, a definition at the level of the fields may become possible (just as we can define a television picture at the level of liquid crystal pixels). Whether or not qualia or consciousness can play any causal role in the physical world remains an open question, with epiphenomenalism acknowledging the existence of qualia while denying it any causal power. The position has been criticized by a number of philosophers, if only because our own consciousness seem to be causally active. In order to avoid epiphenomenalism, one who believes that qualia are nonphysical would need to embrace something like interactionist dualism; or perhaps emergentism, the claim that there are as yet unknown causal relations between the mental and physical. This in turn would imply that qualia can be detected by an external agency through their causal powers. To illustrate: one might be tempted to give as examples of qualia "the pain of a headache, the taste of wine, or the redness of an evening sky". But this list of examples already prejudges a central issue in the current debate on qualia. An analogy might make this clearer. Suppose someone wants to know the nature of the liquid crystal pixels on a television screen, those tiny elements that provide all the distributions of color that go to make up the picture. It would not suffice as an answer to say that they are the "redness of an evening sky" as it appears on the screen

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Qualia We would protest that their real character was being ignored. One can see that relying on the list above assumes that we must tie sensations not only to the notion of given objects in the world (the "head", "wine", "an evening sky"), but also to the properties with which we characterize the experiences themselves ("redness", for example). Nor is it satisfactory to print a little red square as at the top of the article, for, since each person has a slightly different registration of the light-rays, it confusingly suggests that we all have the same response. Imagine in a television shop seeing "a red square" on twenty screens at once, each slightly different—something of vital importance would be overlooked if a single example were to be taken as defining them all. Yet it has been argued whether or not identification with the external object should still be the core of a correct approach to sensation, for there are many who state the definition thus because they regard the link with external reality as crucial. If sensations are defined as "raw feels", there arises a palpable threat to the reliability of knowledge. The reason has been given that, if one sees them as neurophysiological happenings in the brain, it is difficult to understand how they could have any connection to entities, whether in the body or the external world. It has been declared, by John McDowell for example, that to countenance qualia as a "bare presence" prevents us ever gaining a certain ground for our knowledge

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Qualia

Qualia The issue is thus fundamentally an epistemological one: it would appear that access to knowledge is blocked if one allows the existence of qualia as fields in which only virtual constructs are before the mind. His reason is that it puts the entities about which we require knowledge behind a "veil of perception", an occult field of "appearance" which leaves us ignorant of the reality presumed to be beyond it. He is convinced that such uncertainty propels into the dangerous regions of relativism and solipsism: relativism sees all truth as determined by the single observer; solipsism, in which the single observer is the only creator of and legislator for his or her own universe, carries the assumption that no one else exists. These accusations constitute a powerful ethical argument against qualia being something going on in the brain, and these implications are probably largely responsible for the fact that in the 20th century it was regarded as not only freakish, but also dangerously misguided to uphold the notion of sensations as going on inside the head. The argument was usually strengthened with mockery at the very idea of "redness" being in the brain: the question was—and still is—"How can there be red neurons in the brain?" which strikes one as a justifiable appeal to common sense. To maintain a philosophical balance, the argument for "raw feels" needs to be set side by side with the claim above

Biology

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Qualia

Qualia Viewing sensations as "raw feels" implies that initially they have not yet—to carry on the metaphor—been "cooked", that is, unified into "things" and "persons", which is something the mind does after the sensation has responded to the blank input, that response driven by motivation, that is, initially by pain and pleasure, and subsequently, when memories have been implanted, by desire and fear. Such a "raw-feel" state has been more formally identified as "non-epistemic". In support of this view, the theorists cite a range of empirical facts. The following can be taken as representative. There are brain-damaged persons, known as "agnosics" (literally "not-knowing") who still have vivid visual sensations but are quite unable to identify any entity before them, including parts of their own body. There is also the similar predicament of persons, formerly blind, who are given sight for the first time—and consider what it is a newborn baby must experience. A German psychologist of the 19th century, Hermann von Helmholtz, proposed a simple experiment to demonstrate the non-epistemic nature of qualia: his instructions were to stand in front of a familiar landscape, turn your back on it, bend down and look at the landscape between your legs—you will find it difficult in the upside-down view to recognize what you found familiar before. These examples suggest that a "bare presence"—that is, knowledgeless sensation that is no more than evidence—may really occur

Biology

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Qualia

Qualia Present supporters of the non-epistemic theory thus regard sensations as only data in the sense that they are "given" (Latin "datum", "given") and fundamentally involuntary, which is a good reason for not regarding them as basically mental. In the last century they were called "sense-data" by the proponents of qualia, but this led to the confusion that they carried with them reliable proofs of objective causal origins. For instance, one supporter of qualia was happy to speak of the redness and bulginess of a cricket ball as a typical "sense-datum", though not all of them were happy to define qualia by their relation to external entities (see Roy Wood Sellars). The modern argument, following Sellars' lead, centers on how we learn under the regime of motivation to interpret the sensory evidence in terms of "things", "persons", and "selves" through a continuing process of feedback. The definition of qualia thus is governed by one's point of view, and that inevitably brings with it philosophical and neurophysiological presuppositions. The question, therefore, of what qualia can be raises profound issues in the philosophy of mind, since some materialists want to deny their existence altogether: on the other hand, if they are accepted, they cannot be easily accounted for as they raise the difficult problem of consciousness. There are committed dualists such as Richard L

Biology

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Qualia

Qualia Amoroso or John Hagelin who believe that the mental and the material are two distinct aspects of physical reality like the distinction between the classical and quantum regimes. In contrast, there are direct realists for whom the thought of qualia is unscientific as there appears to be no way of making them fit within the modern scientific picture; and there are committed proselytizers for a final truth who reject them as forcing knowledge out of reach.

Biology

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Qualia

Marinoan glaciation The was a period of worldwide glaciation that lasted from approximately 650 to 635 Ma (million years ago) during the Cryogenian period. The glaciation may have covered the entire planet, in an event called the Snowball Earth. The end of the glaciation may have been sped by the release of methane from equatorial permafrost. The name is derived from the stratigraphic terminology of the Adelaide Geosyncline (Adelaide Rift Complex) in South Australia and is taken from the Adelaide suburb of Marino. The term Marinoan Series was first used in a 1950 paper by Douglas Mawson and Reg Sprigg to subdivide the Neoproterozoic rocks of the Adelaide area and encompassed all strata from the top of the Brighton Limestone to the base of the Cambrian. The corresponding time period, referred to as the Marinoan Epoch, spanned from the middle Cryogenian to the top of the Ediacaran in modern terminology. Mawson recognised a glacial episode within the Marinoan Epoch which he referred to as the Elatina glaciation after the 'Elatina Tillite' (now Elatina Formation) where he found the evidence. However, the term came into common usage because it was the glaciation that occurred during the Marinoan Epoch, as distinct from the earlier glaciation during the Sturtian Epoch (the time period of deposition of the older Sturtian Series). The term was later applied globally to any glaciogenic formations assumed (directly or indirectly) to correlate with Mawson's original Elatina glaciation in South Australia

Biology

https://en.wikipedia.org/wiki?curid=21407814

Marinoan glaciation

Marinoan glaciation Recently, there has been a move to return to the term Elatina glaciation in South Australia because of uncertainties regarding global correlation and because an Ediacaran glacial episode (Gaskiers) also occurs within the wide-ranging Marinoan Epoch. Emerging evidence suggests that the Earth underwent a number of glaciations during the Neoproterozoic era. There were three (or possibly four) significant ice ages during the late Neoproterozoic. These periods of nearly complete glaciation of Earth are often referred to as "Snowball Earth", where it is hypothesized that at times the planet was covered by ice thick. Of these glaciations, the Sturtian glaciation was the most significant, whereas the Marinoan was a shorter, but still worldwide glaciation. Other Cryogenian glaciations were probably small and not global as compared to the Marinoan or Sturtian glaciations. During the Marinoan glaciation, characteristic glacial deposits indicate that Earth suffered one of the most severe ice ages in its history. Glaciers extended and contracted in a series of rhythmic pulses, possibly reaching as far as the equator. The melting of the Snowball Earth is associated with greenhouse warming due to the accumulation of high levels of carbon dioxide in the atmosphere. Even though much evidence has been lost through geological changes, field investigations show evidence of the in China, Svalbard archipelago and South Australia

Biology

https://en.wikipedia.org/wiki?curid=21407814

Marinoan glaciation

Marinoan glaciation In Guizhou Province, China, glacial rocks were found to be underlying and overlying a layer of volcanic ashes which contained zircon minerals, which could be dated through radioisotopes. Glacial deposits in South Australia are approximately the same age (about 630 Ma), confirmed by similar stable carbon isotopes, mineral deposits (including sedimentary barite), and other unusual sedimentary structures. Two diamictite-rich layers in the top of the Neoproterozoic strata of the northeastern Svalbard archipelago represent the first and final phases of the Marinoan glaciation. According to Eyles and Young, the Marinoan is a second episode of Neoproterozoic glaciation (680–690 Ma) occurring in the Adelaide Geosyncline. According to them, "It is separated from the Sturtian by a thick succession of sedimentary rocks containing no evidence of glaciation. This glacial phase could correspond to the recently described Ice Brooke formation in the northern Cordillera."

Biology

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Marinoan glaciation

Battle for Births The was one of four economic battles that took place in Fascist Italy (1922–1943), the others being the Battle for Grain (to make the country more self-sufficient), the Battle for the Lira (an increase in the value of the currency), and the Battle for Land (which involved policies of land reclamation). Prime Minister Benito Mussolini, often known as "Il Duce", envisioned an Italian Empire to rival that of the Romans, and in order to carry out this objective, foresaw the need to increase the population. Mussolini pursued an often aggressive foreign policy to achieve his colonial aims: the Italian army invaded Abyssinia (now Ethiopia) in October 1935. The phrase "Battle for Births" was also used, in contemporary sources, to describe policies developed in Nazi Germany. Mussolini feuded with the Catholic Church over a number of issues in his time in office, but their views, at that time, coincided on the issue of gender roles and contraception: both felt that women should assume a role as wife and mother, and both disagreed with contraception and abortion, with Mussolini banning the former. The began in 1927: Mussolini introduced a number of measures to encourage reproduction, with an objective of increasing the population from 40 million to 60 million by 1950. Loans were offered to married couples, with part of the loan cancelled for each new child, and any married man who had more than six children was made exempt from taxation

Biology

https://en.wikipedia.org/wiki?curid=21407921

Battle for Births

Battle for Births Mussolini, who had developed a cult of personality, argued that the Italian people had a duty to himself to produce as many children as possible according to Lisa (2009) and Talent et Al. In correspondence with these incentives, laws were brought in to penalize any citizens who proved to be less productive. Bachelors were taxed increasingly, and by the late 1930s, the civil service began recruiting and promoting only those who were fertile and married. The state exercised some control over the number of women in employment through nationalized businesses, and the state-owned railway company sacked all women employed since 1915, bar war widows. These policies extended to private industry as well, with the majority of companies reserving promotions for married men. Unlike the Battle for Grain and Battle for Land, which were considered to be moderately successful, the is seen as a failure. By 1950—seven years after Mussolini had been ousted by King Victor Emmanuel III, and five years since his execution—Italy's population stood at 47.5 million. Marriage rates stayed virtually the same during Mussolini's reign, and birth rates decreased until 1936, after which there was a modest increase. The birth rate of 112 per 1000 in 1936 was below that of pre-World War I levels (1911: 147 per 1000). Mussolini felt that the lack of enthusiasm shown by the Italian nation had cost him 15 army divisions in World War II (in which Italy had fought alongside the Axis powers).

Biology

https://en.wikipedia.org/wiki?curid=21407921

Battle for Births

Chesson's index The Manly-Chesson's Index (or Manly's alpha, or Chesson's index) refers to an index to determine selective feeding on discrete food items. It was described separately by Bryan F. J. Manly and Jean Chesson in the 1970's . It was initially described for two different food types, but was later extended to include more food types . The index for two food types is calculated as: formula_1. Where formula_2 and formula_3 are the number of individuals of present at the start for each species and formula_4 and formula_5 are the number of items consumed of each type respectively. formula_6 is the estimate of preference. The use of this index has been widespread with more than 400 citations in the scientific literature.

Biology

https://en.wikipedia.org/wiki?curid=21410579

Chesson's index

Casamino acid Casamino acids is a mixture of amino acids and some very small peptides obtained from acid hydrolysis of casein. It is typically used in microbial growth media. It has all the essential amino acids except tryptophan, which is destroyed by digestion with sulfuric or hydrochloric acid. Casamino acids is similar to tryptone, the latter differing by being an incomplete enzymatic hydrolysis with some oligopeptides present, while casamino acids is predominantly free amino acids. Casamino acids supplies a completely hydrolyzed protein nitrogen source. It contains a small amount of cystine. Tryptophan and vitamins are destroyed by the acid treatment. The remaining amino acids (in varying amounts) are a source of nutrients for various microorganisms. Amino acids are highly soluble and suitable for use in tissue culture. Salt content is typically 30-40%. Casamino acids are either found in the Daptacel brand DTaP vaccine or used in its manufacture.

Biology

https://en.wikipedia.org/wiki?curid=21412354

Casamino acid

POLR3GL Polymerase (RNA) III (DNA directed) polypeptide G (32kD)-like also known as is a protein which in humans is encoded by the "POLR3GL" gene.

Biology

https://en.wikipedia.org/wiki?curid=21416985

POLR3GL

ConsensusPathDB The is a molecular functional interaction database, integrating information on protein interactions, genetic interactions signaling, metabolism, gene regulation, and drug-target interactions in humans. currently (release 30) includes such interactions from 32 databases. is freely available for academic use under http://ConsensusPathDB.org. The is accessible via a web interface providing a variety of functions. Using the web interface users can search for physical entities (e.g. proteins, metabolites etc.) or pathways using common names or accession numbers (e.g. UniProt identifiers). Selected interactions can be visualized in an interactive environment as expandable networks. currently allows users to export their models in BioPAX format or as image in several formats. Users can search for shortest paths of functional interactions between physical entities, based on all interactions in the database. The pathway search can be constrained by forbidding passing through certain physical entities. Users can upload their own interaction networks in BioPAX, PSI-MI or SBML files in order to validate and/or extend those networks in the context of the interactions in ConsensusPathDB. Using the web-interface of the database, one can perform overrepresentation analysis, based on biochemical pathways or on neighbourhood-based entity sets (NESTs) that constitute sub-networks of the overall interaction network containing all physical entities around a central one within a "radius" (number of interactions from the center)

Biology

https://en.wikipedia.org/wiki?curid=21423678

ConsensusPathDB

ConsensusPathDB For each predefined set (pathway / NEST), a P-value is computed based on the hypergeometric distribution. It reflects the significance of the observed overlap between the user-specific input gene list and the members of the predefined set. Over-representation analyses can be performed with user-specified genes or metabolites.

Biology

https://en.wikipedia.org/wiki?curid=21423678

ConsensusPathDB

Mu hemoglobin is a predicted protein encoded in the "HBM" gene. The mRNA is expressed at moderate levels, but the protein has not been detected by mass spectrometry. The order of genes is: 5' - zeta - pseudozeta - mu - pseudoalpha-1 - alpha-2 - alpha-1 - theta1 - 3'.

Biology

https://en.wikipedia.org/wiki?curid=21424477

Mu hemoglobin

Defaunation is the global, local or functional extinction of animal populations or species from ecological communities. The growth of the human population, combined with advances in harvesting technologies, has led to more intense and efficient exploitation of the environment. This has resulted in the depletion of large vertebrates from ecological communities, creating what has been termed "empty forest". differs from extinction; it includes both the disappearance of species and declines in abundance. effects were first implied at the Symposium of Plant-Animal Interactions at the University of Campinas, Brazil in 1988 in the context of neotropical forests. Since then, the term has gained broader usage in conservation biology as a global phenomenon. It is estimated that more than 50 percent of all wildlife has been lost in the last 40 years. in 2020 it is estimated that 68% of the world's wildlife will be lost. In South America, there is believed to be a 70 percent loss. In November 2017, over 15,000 scientists around the world issued a second warning to humanity, which, among other things, urged for the development and implementation of policies to halt "defaunation, the poaching crisis, and the exploitation and trade of threatened species." The intensive hunting and harvesting of animals threatens endangered vertebrate species across the world. Game vertebrates are considered valuable products of tropical forests and savannas

Biology

https://en.wikipedia.org/wiki?curid=21424701

Defaunation

Defaunation In Brazilian Amazonia, 23 million vertebrates are killed every year; large-bodied primates, tapirs, white-lipped peccaries, giant armadillos, and tortoises are some of the animals most sensitive to harvest. Overhunting can reduce the local population of such species by more than half, as well as reducing population density. Populations located nearer to villages are significantly more at risk of depletion. Abundance of local game species declines as density of local settlements, such as villages, increases. Hunting and poaching may lead to local population declines or extinction in some species. Most affected species undergo pressure from multiple sources but the scientific community is still unsure of the complexity of these interactions and their feedback loops. One case study in Panama found an inverse relationship between poaching intensity and abundance for 9 of 11 mammal species studied. In addition, preferred game species experienced greater declines and had higher spatial variation in abundance. Human population growth results in changes in land-use, which can cause natural habitats to become fragmented, altered, or destroyed. Large mammals are often more vulnerable to extinction than smaller animals because they require larger home ranges and thus are more prone to suffer the effects of deforestation. Large species such as elephants, rhinoceroses, large primates, tapirs and peccaries are the first animals to disappear in fragmented rainforests

Biology

https://en.wikipedia.org/wiki?curid=21424701

Defaunation

Defaunation A case study from Amazonian Ecuador analyzed two oil-road management approaches and their effects on the surrounding wildlife communities. The free-access road had forests that were cleared and fragmented and the other had enforced access control. Fewer species were found along the first road with density estimates being almost 80% lower than at the second site that which had minimal disturbance. This finding suggests that disturbances affected the local animals' willingness and ability to travel between patches. Fragmentation lowers populations while increasing extinction risk when the remaining habitat size is small. When there is more unfragmented land, there is more habitat for more diverse species. A larger land patch also means it can accommodate more species with larger home ranges. However, when patch size decreases, there is an increase in the number of isolated fragments which can remain unoccupied by local fauna. If this persists, species may become extinct in the area. A study on deforestation in the Amazon looked at two patterns of habitat fragmentation: "fish-bone" in smaller properties and another unnamed large property pattern. The large property pattern contained fewer fragments than the smaller fish-bone pattern. The results suggested that higher levels of fragmentation within the fish-bone pattern led to the loss of species and decreased diversity of large vertebrates

Biology

https://en.wikipedia.org/wiki?curid=21424701

Defaunation

Defaunation Human impacts, such as the fragmentation of forests, may cause large areas to lose the ability to maintain biodiversity and ecosystem function due to loss of key ecological processes. This can consequently cause changes within environments and skew evolutionary processes. In North America, wild bird populations have declined by 29%, or around three billion, since 1970, largely as the result of anthropogenic causes such as habitat loss for human use, the primary driver of the decline, along with widespread use of neonicotinoid insecticides and the proliferation of domesticated cats allowed to roam outdoors. Human influences, such as colonization and agriculture, have caused species to become distributed outside of their native ranges. Fragmentation also has cascading effects on native species, beyond reducing habitat and resource availability; it leaves areas vulnerable to non-native invasions. Invasive species can out-compete or directly prey upon native species, as well as alter the habitat so that native species can no longer survive. In extinct animal species for which the cause of extinction is known, over 50% were affected by invasive species. For 20% of extinct animal species, invasive species are the only cited cause of extinction. Invasive species are the second-most important cause of extinction for mammals. Tropical regions are the most heavily impacted by defaunation

Biology

https://en.wikipedia.org/wiki?curid=21424701

Defaunation

Defaunation These regions, which include the Brazilian Amazon, the Congo Basin of Central Africa, and Indonesia, experience the greatest rates of overexploitation and habitat degradation. However, specific causes are varied, and areas with one endangered group (such as birds) do not necessarily also have other endangered groups (such as mammals, insects, or amphibians). Deforestation of the Brazilian Amazon leads to habitat fragmentation and overexploitation. Hunting pressure in the Amazon rainforest has increased as traditional hunting techniques have been replaced by modern weapons such as shotguns. Access roads built for mining and logging operations fragment the forest landscape and allow hunters to move into forested areas which previously were untouched. The bushmeat trade in Central Africa incentivizes the overexploitation of local fauna. Indonesia has the most endangered animal species of any area in the world. International trade in wild animals, as well as extensive logging, mining and agriculture operations, drive the decline and extinction of numerous species. Inbreeding and genetic diversity loss often occur with endangered species populations because they have small and/or declining populations. Loss of genetic diversity lowers the ability of a population to deal with change in their environment and can make individuals within the community homogeneous. If this occurs, these animals are more susceptible to disease and other occurrences that may target a specific genome

Biology

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Defaunation

Defaunation Without genetic diversity, one disease could eradicate an entire species. Inbreeding lowers reproduction and survival rates. It is suggested that these genetic factors contribute to the extinction risk in threatened/endangered species. The consequences of defaunation can be expected to affect the plant community. There are three non-mutually exclusive conclusions as to the consequences on tropical forest plant communities: One recent study analyzed seedling density and composition from two areas, Los Tuxtlas and Montes Azules. Los Tuxtlas, which is affected more by human activity, showed higher seedling density and a smaller average number of different species than in the other area. Results suggest that an absence of vertebrate dispersers can change the structure and diversity of forests. As a result, a plant community that relies on animals for dispersal could potentially have an altered biodiversity, species dominance, survival, demography, and spatial and genetic structure. Poaching is likely to alter plant composition because the interactions between game and plant species varies in strength. Some game species interact strongly, weakly, or not at all with species. A change in plant species composition is likely to be a result because the net effect removal of game species varies among the plant species they interact with. As large-bodied vertebrates are increasingly lost from seed-dispersal networks, small-bodied seed dispersers (i.e. bats, birds, dung beetles) and seed predators (i.e

Biology

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Defaunation

Defaunation rodents) are affected. leads to reduced species diversity. This is due to relaxed competition; small-bodied species normally compete with large-bodied vertebrates for food and other resources. As an area becomes defaunated, dominant small-bodied species take over, crowding out other similar species and leading to an overall reduced species diversity. The loss of species diversity is reflective of a larger loss of biodiversity, which has consequences for the maintenance of ecosystem services. The quality of the physical habitat may also suffer. Bird and bat species (many of who are small bodied seed dispersers) rely on mineral licks as a source of sodium, which is not available elsewhere in their diets. In defaunated areas in the Western Amazon, mineral licks are more thickly covered by vegetation and have lower water availability. Bats were significantly less likely to visit these degraded mineral licks. The degradation of such licks will thus negatively affect the health and reproduction of bat populations. has negative consequences for seed dispersal networks as well. In the western Amazon, birds and bats have separate diets and thus form separate guilds within the network. It is hypothesized that large-bodied vertebrates, being generalists, connect separate guilds, creating a stable, resilient network. results in a highly modular network in which specialized frugivores instead act as the connector hubs

Biology

https://en.wikipedia.org/wiki?curid=21424701

Defaunation