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Threshold Model
In mathematical or statistical modeling a threshold model is any model where a threshold value, or set of threshold values, is used to distinguish ranges of values where the behaviour predicted by the model varies in some important way. A particularly important instance arises in toxicology, where the model for the effect of a drug may be that there is zero effect for a dose below a critical or threshold value, while an effect of some significance exists above that value.Dodge, Y. (2003) ''The Oxford Dictionary of Statistical Terms'', OUP. Certain types of regression model may include threshold effects. Collective behavior Threshold models are often used to model the behavior of groups, ranging from social insects to animal herds to human society. Classic threshold models were introduced by Sakoda, in his 1949 dissertation and the Journal of Mathematical Sociology (JMS vol 1 #1, 1971). They were subsequently developed by Schelling, Axelrod, and Granovetter to model collectiv ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Standard Deviation Diagram
Standard may refer to: Symbols * Colours, standards and guidons, kinds of military signs * Heraldic flag, Standard (emblem), a type of a large symbol or emblem used for identification Norms, conventions or requirements * Standard (metrology), an object that bears a defined relationship to a unit of measure used for calibration of measuring devices * Standard (timber unit), an obsolete measure of timber used in trade * Breed standard (also called bench standard), in animal fancy and animal husbandry * BioCompute Object, BioCompute Standard, a standard for next generation sequencing * De facto standard, ''De facto'' standard, product or system with market dominance * Gold standard, a monetary system based on gold; also used metaphorically for the best of several options, against which the others are measured * Internet Standard, a specification ratified as an open standard by the Internet Engineering Task Force * Learning standards, standards applied to education content * Stand ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Hormesis
Hormesis is a two-phased dose-response relationship to an environmental agent whereby low-dose amounts have a beneficial effect and high-dose amounts are either inhibitory to function or toxic. Within the hormetic zone, the biological response to low-dose amounts of some stressors is generally favorable. An example is the breathing of oxygen, which is required in low amounts (in air) via respiration in living animals, but can be toxic in high amounts, even in a managed clinical setting. In toxicology, hormesis is a dose-response phenomenon to xenobiotics or other stressors. In physiology and nutrition, hormesis has regions extending from low-dose deficiencies to homeostasis, and potential toxicity at high levels. Physiological concentrations of an agent above or below homeostasis may adversely affect an organism, where the hormetic zone is a region of homeostasis of balanced nutrition. In pharmacology, the hormetic zone is similar to the therapeutic window. In the context of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
James Shields (academic)
James Shields (21 November 1918 – 20 June 1978) was a Scottish psychiatric geneticist and twin researcher. In the 1960s, he worked with Irving Gottesman on a twin study of schizophrenia at the Medical Research Council Psychiatric Genetics Unit at Maudsley Hospital in London, England. This study, known as the Maudsley twin study, is now considered a landmark in the field. He had previously begun working for Eliot Slater at Maudsley after serving in the United Kingdom's Royal Artillery during World War II. He was a fellow of the Eugenics Society The Adelphi Genetics Forum is a non-profit learned society based in the United Kingdom. Its aims are "to promote the public understanding of human heredity and to facilitate informed debate about the ethical issues raised by advances in reproducti ... and the International Society for Twin Studies. After Shields died in 1978, Gottesman founded the annual James Shields Award for Lifetime Contributions to Twin Research in his honor. Refe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Irving Gottesman
Irving Isadore Gottesman (December 29, 1930 – June 29, 2016) was an American professor of psychology who devoted most of his career to the study of the genetics of schizophrenia. He wrote 17 books and more than 290 other publications, mostly on schizophrenia and behavioral genetics, and created the first academic program on behavioral genetics in the United States. He won awards such as the Hofheimer Prize for Research, the highest award from the American Psychiatric Association for psychiatric research. Lastly, Gottesman was a professor in the psychology department at the University of Minnesota, where he received his Doctor of Philosophy, Ph.D. A native of Ohio, Gottesman studied psychology for his undergraduate and graduate degrees, became a faculty member at various universities, and spent most of his career at the University of Virginia and the University of Minnesota. He is known for researching schizophrenia in Twin#IdenticalTwins, identical twins to document the contr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Diabetes
Diabetes mellitus, commonly known as diabetes, is a group of common endocrine diseases characterized by sustained high blood sugar levels. Diabetes is due to either the pancreas not producing enough of the hormone insulin, or the cells of the body becoming unresponsive to insulin's effects. Classic symptoms include polydipsia (excessive thirst), polyuria (excessive urination), polyphagia (excessive hunger), weight loss, and blurred vision. If left untreated, the disease can lead to various health complications, including disorders of the cardiovascular system, eye, kidney, and nerves. Diabetes accounts for approximately 4.2 million deaths every year, with an estimated 1.5 million caused by either untreated or poorly treated diabetes. The major types of diabetes are type 1 and type 2. The most common treatment for type 1 is insulin replacement therapy (insulin injections), while anti-diabetic medications (such as metformin and semaglutide) and lifestyle modificatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Cyril Clarke
Sir Cyril Astley Clarke (22 August 1907 – 21 November 2000) was a British physician, geneticist and lepidopterist. He was honoured for his pioneering work on prevention of Rh disease of the newborn, and also for his work on the genetics of the Lepidoptera (butterflies and moths). Biography Cyril Clarke was born on 22 August 1907 in Leicester, England and received his school education at Wyggeston Grammar School for Boys, Leicester and at the independent Oundle School near Peterborough. His interest in butterflies and moths began at school. His studied natural science at Gonville and Caius College, Cambridge, graduating in 1929, and then medicine at Guy's Hospital, London, graduating in 1932. During the Second World War he worked as a medical specialist in the Royal Naval Volunteer Reserve. After the war Clarke worked as a registrar at the Queen Elizabeth Hospital in Birmingham and then as Consultant Physician at the United Liverpool Hospitals. In 1963 he was appointed Director ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Douglas Scott Falconer
Douglas Scott Falconer (10 March 1913 in Oldmeldrum, Aberdeenshire – 23 February 2004 in Edinburgh) was a Scottish geneticist known for his work in quantitative genetics. Falconer's book ''Introduction to quantitative genetics'' was written in 1960 and became a valuable reference for generations of scientists. Its latest edition dates back to 1996 and is coauthored by Trudy Mackay. Falconer graduated with first class honors in zoology from the University of St Andrews in 1940. He then received his PhD from the University of Cambridge in 1943. He eventually got an honorary ScD from Cambridge in 1969. In 1951, Falconer described a novel mouse mutant that he called reeler for its peculiar gait. Later research using these mice has led to the discovery of reelin, a protein playing important roles in corticogenesis, neuronal migration, and plasticity. In 1964, he introduced the use of liability threshold models into human disease & trait modeling. In 1973, he was announced ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Guinea Pig
The guinea pig or domestic guinea pig (''Cavia porcellus''), also known as the cavy or domestic cavy ( ), is a species of rodent belonging to the genus ''Cavia'', family Caviidae. Animal fancy, Breeders tend to use the name "cavy" for the animal, but "guinea pig" is more commonly used in scientific and laboratory contexts. Despite their name, guinea pigs are not native to Guinea (region), Guinea, nor are they closely related to suidae, pigs. Instead, they originated in the Andes region of South America, where wild guinea pigs can still be found today. Studies based on biochemistry and DNA Hybrid (biology), hybridization suggest they are domestication, domesticated animals that do not exist naturally in the wild, but are descendants of a closely related cavy species such as ''Montane guinea pig, C. tschudii''. Originally, they were domesticated as livestock (source of meat) in the Andean region and are still consumed in some parts of the world. In Western society, the guin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Sewall Wright
Sewall Green Wright ForMemRS HonFRSE (December 21, 1889March 3, 1988) was an American geneticist known for his influential work on evolutionary theory and also for his work on path analysis. He was a founder of population genetics alongside Ronald Fisher and J. B. S. Haldane, which was a major step in the development of the modern synthesis combining genetics with evolution. He discovered the inbreeding coefficient and methods of computing it in pedigree animals. He extended this work to populations, computing the amount of inbreeding between members of populations as a result of random genetic drift, and along with Fisher he pioneered methods for computing the distribution of gene frequencies among populations as a result of the interaction of natural selection, mutation, migration and genetic drift. Wright also made major contributions to mammalian and biochemical genetics. Biography Sewall Wright was born in Melrose, Massachusetts, to Philip Green Wright and Elizabe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Schizophrenia
Schizophrenia () is a mental disorder characterized variously by hallucinations (typically, Auditory hallucination#Schizophrenia, hearing voices), delusions, thought disorder, disorganized thinking and behavior, and Reduced affect display, flat or inappropriate affect. Symptoms Prodrome, develop gradually and typically begin during young adulthood and rarely resolve. There is no objective diagnostic test; diagnosis is based on observed behavior, a psychiatric history that includes the person's reported experiences, and reports of others familiar with the person. For a diagnosis of schizophrenia, the described symptoms need to have been present for at least six months (according to the DSM-5) or one month (according to the ICD-11). Many people with schizophrenia have other mental disorders, especially mood disorder, mood, anxiety disorder, anxiety, and substance use disorders, substance use disorders, as well as obsessive–compulsive disorder (OCD). About 0.3% to 0.7% of peo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Normal Distribution
In probability theory and statistics, a normal distribution or Gaussian distribution is a type of continuous probability distribution for a real-valued random variable. The general form of its probability density function is f(x) = \frac e^\,. The parameter is the mean or expectation of the distribution (and also its median and mode), while the parameter \sigma^2 is the variance. The standard deviation of the distribution is (sigma). A random variable with a Gaussian distribution is said to be normally distributed, and is called a normal deviate. Normal distributions are important in statistics and are often used in the natural and social sciences to represent real-valued random variables whose distributions are not known. Their importance is partly due to the central limit theorem. It states that, under some conditions, the average of many samples (observations) of a random variable with finite mean and variance is itself a random variable—whose distribution c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
Mendelian Disease
Mendelian inheritance (also known as Mendelism) is a type of biological inheritance following the principles originally proposed by Gregor Mendel in 1865 and 1866, re-discovered in 1900 by Hugo de Vries and Carl Correns, and later popularized by William Bateson. These principles were initially controversial. When Mendel's theories were integrated with the Boveri–Sutton chromosome theory of inheritance by Thomas Hunt Morgan in 1915, they became the core of classical genetics. Ronald Fisher combined these ideas with the theory of natural selection in his 1930 book '' The Genetical Theory of Natural Selection'', putting evolution onto a mathematical footing and forming the basis for population genetics within the modern evolutionary synthesis. History The principles of Mendelian inheritance were named for and first derived by Gregor Johann Mendel, a nineteenth-century Moravian monk who formulated his ideas after conducting simple hybridization experiments with pea p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
