The Yerkes-Dodson law demonstrates an empirical relationship between arousal and performance. It dictates that performance increases with cognitive arousal but only to a certain point: when levels of arousal become too high, performance will decrease. A corollary is that there is an optimal level of arousal for a given task. It is a scientific principal developed by psychologists Robert M. Yerkes and J. D. Dodson in 1908 and is grounded within the discourses of biopsychology and neuroscience. The process is often demonstrated graphically as an inverted U-shaped curve, incre ...

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Ankylosing spondylitis (AS) is a chronic, progressive inflammatory arthritis primarily affecting spine and sacroiliac joints, causing eventual fusion of the spine; it is a member of the group of the spondylarthropathies. Complete fusion results in a complete rigidity of the spine, a condition known as bamboo spine. Treatment is with physiotherapy and medication. Some cases remain mild, while other result in marked disability. Ankylosing spondylitis - Signs and symptoms. The typical patient is ...

Including:

• Ankylosing spondylitis - Signs and symptoms
• Ankylosing spondylitis - Diagnosis
• Ankylosing spondylitis - Pathophysiology
• Ankylosing spondylitis - Epidemiology
• Ankylosing spondylitis - Therapy
• Ankylosing spondylitis - Prognosis
• Ankylosing spondylitis - Famous patients
• Ankylosing spondylitis - Reference

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Milk most often means the nutrient fluid produced by the mammary glands of female mammals. It provides the primary source of nutrition for newborns before they are able to digest more diverse foods. It is also processed into dairy products such as cream, butter, yoghurt, ice-cream, gelato, cheese, casein, whey protein, lactose, condensed milk, powdered milk, and many other food-additive and industrial products. It can also be used to mean: The white juice and the processed meat of the coconut in, more or less, liqu ...

Including:

• Milk - Composition and nutrition
• Milk - Cow's milk
• Milk - Commercial processing of milk
• Milk - Distribution
• Milk - Varieties and brands
• Milk - Other milk animals
• Milk - Curdling

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Iridology is an alternative medicine practice in which patterns, colors and other characteristics of stromal fibers of the iris are examined for information about a patient's systemic health. Practitioners match their observations to iris charts which divide the iris into many zones believed to correspond to specific parts of the human body. Little if any rigorous scientific evidence exists confirming any such link between aspects of the iris and a patient's state of health and there is no recognized ca ...

Including:

• Iridology - Methods
• Iridology - History
• Iridology - Support for iridology
• Iridology - Criticism of iridology
• Iridology - Scientific research into iridology
• Iridology - Regulation licensure and certification
• Iridology - Related practices

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White noise (Sample ▶ (help·info)) is a random signal (or process) with a flat power spectral density. In other words, the signal's power spectral density has equal power in any band, at any centre frequency, having a given bandwidth. An infinite-bandwidth white noise signal is purely a theoretical construct. By having power at all frequencies, the total power of such a signal is infinite. In practice, a signal can be "white" with a flat spectrum over ...

Including:

• White noise - Statistical properties
• White noise - Colors of noise
• White noise - Applications
• White noise - Mathematical definition
• White noise - White random vector
• White noise - White random process white noise
• White noise - Random vector transformations
• White noise - Simulating a random vector
• White noise - Whitening a random vector
• White noise - Random signal transformations
• White noise - Simulating a continuous-time random signal
• White noise - Whitening a continuous-time random signal
• White noise - External link

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Symptoms include multiple motor and one or more vocal tics present at some time during the disorder although not necessarily simultaneously; the occurrence of tics many times a day (usually in bouts) nearly every day or intermittently throughout a span of more than one year; the periodic change in the number, frequency, type and location of the tics, and in the waxing and waning of their severity; symptoms disappearing for weeks or mon ...

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Tourette syndrome, Tourette syndrome - Symptoms, Tourette syndrome - Diagnosis, Tourette syndrome - Treatment, Tourette syndrome - Genetics, Tourette syndrome - Famous People With Tourette's, Tourette syndrome - References in the Entertainment Industry, Tourette syndrome - In fiction, Tourette syndrome - On the Internet, Tourette syndrome - In Music

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The essential elements of a scientific method are iterations, recursions, interleavings and orderings of the following: Characterizations (Quantifications, observations and measurements) Hypotheses (theoretical, hypothetical explanations of observations and measurements) Predictions (reasoning including logical deduction from hypotheses and theories) Experi ...

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Scientific method, Scientific method - Elements of scientific method, Scientific method - Characterizations, Scientific method - Hypotheses development, Scientific method - Predictions from the hypotheses, Scientific method - Experiments, Scientific method - Evaluations and iterations, Scientific method - Testing and improvements, Scientific method - Confirmations, Scientific method - Scope and goals, Scientific method - Scientific communities, Scientific method - Peer review evaluations, Scientific method - Reproduction and record-keeping, Scientific method - History, Scientific method - Philosophical issues, Scientific method - Scientific method and the practice of science, Scientific method - Formal approaches, Scientific method - Quotations, Scientific method - Notes, Scientific method - Historical references to scientific method

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In probability theory and statistics, the variance of a random variable is a measure of its statistical dispersion, indicating how far from the expected value its values typically are. The variance of a real-valued random variable is its second central moment, and it also happens to be its second cumulant. The variance of a random variable is the square of its standard deviation. Variance - Definition. If μ = E(X) is the expected value (mean) of the random variable X, then the variance is ...

Including:

• Variance - Definition
• Variance - Properties
• Variance - Population variance and sample variance
• Variance - An unbiased estimator
• Variance - Generalizations
• Variance - History
• Variance - Moment of inertia

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Based on the single-origin hypothesis, black supremacists believe that, because human beings first evolved in Africa with darkly pigmented skin, blacks are more advanced than other peoples of the planet. They claim that the early, powerful black civilizations of Nubia and early dynastic Egypt are proof of inherent melanin-based superiority (see Afrocentrism). This contention, known generally as "Melanin Theory", is founded upon a combination of scientific information and pseudo-scientific claims, and has been a subject of interest among some African-Americans since the discov ...

See also:

Black supremacy, Black supremacy - Black supremacy versus White supremacy, Black supremacy - Rastafari, Black supremacy - Nation of Islam through Malcolm X, Black supremacy - Melanin and Melanin Theory, Black supremacy - Black supremacists and organizations, Black supremacy - Compare

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Early warning signs regarding the attacks first surfaced in 1996, when Eric Harris created a private website on America Online. The original site was set up to host Doom levels that he and Klebold had created, mainly for friends. Throughout the year, Harris began a primitive blog on the site, which included jokes and small journal entries concerning his thoughts on parents, school, and friends. By the end of the year, the site contained instructions on how to cause mischief, as well as instructions on how to make explosives, and logs of the ...

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Columbine High School massacre, Columbine High School massacre - Warning signs, Columbine High School massacre - Crime punishment and retaliation, Columbine High School massacre - Journals and videos, Columbine High School massacre - Firearms, Columbine High School massacre - April 20 1999: shooting at Columbine High, Columbine High School massacre - The shooting begins, Columbine High School massacre - The library massacre, Columbine High School massacre - Suicide of the shooters, Columbine High School massacre - The shooting ends, Columbine High School massacre - Aftermath, Columbine High School massacre - Third shooter theory, Columbine High School massacre - Aftershock and the search for reasons, Columbine High School massacre - Long-term impact, Columbine High School massacre - Cultural impact, Columbine High School massacre - Notes

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An almanac (also spelled almanack, especially in Commonwealth English) is an annual publication containing tabular information in a particular field or fields often arranged according to the calendar. Astronomical data and various statistics are also found in almanacs, such as the times of the rising and setting of the sun and moon, eclipses, hours of full tide, stated festivals of churches, terms of courts, lists of all types, timelines, and more. The word almanac comes from the Arabic al-manaakh, "the climate," ...

Including:

• Almanac - Contemporary Almanacs

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In statistics, the term cross-correlation is sometimes used to refer to the covariance cov(X, Y) between two random vectors X and Y, in order to distinguish that concept from the "covariance" of a random vector X, which is understood to be the matrix of covariances between the scalar components of X. In signal processing, the cross-correlation (or sometimes "cross-covariance") is a measure of similarity of two signals, commonly used to find features in an unknown signal by c ...

Including:

• Cross-correlation - Properties

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Radar - Distance measurement. The easiest way to measure the range of an object is to broadcast a short pulse of radio signal, and then evaluate the time it takes for the reflection to return. The distance is one-half the product of round trip time (because the signal has to travel to the target and then back to the receiver) and the speed of the signal. where c is the speed of light in a vacuum, and τ is the round trip time. For radar the speed of signal is the speed of lig ...

See also:

Radar, Radar - Principles, Radar - Overview, Radar - Reflection, Radar - Radar equation, Radar - Polarization, Radar - Interference, Radar - Radar Signal Processing, Radar - Distance measurement, Radar - Speed measurement, Radar - Reduction of interference effects, Radar - Radar Engineering, Radar - Antenna design, Radar - Frequency bands, Radar - Specific radar systems, Radar - Radar modulators, Radar - Uses of radar

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Conjunctivitis (commonly called "pinkeye") is an inflammation of the conjunctiva (the outermost layer of the eye and the inner surface of the eyelids), often due to infection. There are three common varieties of conjunctivitis, viral, allergic, and bacterial. Other causes of conjunctivitis include thermal and ultraviolet burns, chemicals, toxins, overuse of contact lenses, foreign bodies, vitamin deficiency, dry eye, dryness due to inadequate lid closure, exposure to chickens infected with Newcastle disease, epithelial dysplasia (pre-cancerous changes), and ...

Including:

• Conjunctivitis - Epidemiology
• Conjunctivitis - Diagnosis
• Conjunctivitis - Symptoms
• Conjunctivitis - Signs
• Conjunctivitis - Differential diagnosis
• Conjunctivitis - Investigations
• Conjunctivitis - Treatment and management

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Theodore von Kármán (Szőllőskislaki Kármán Tódor) (May 11, 1881 – May 6, 1963) was an engineer and physicist who was active primarily in the fields of aeronautics during the seminal era in the 1940s and 1950s. He is personally responsible for many key advances in aerodynamics, notably his work on supersonic and hypersonic airflow characterization. He was born in Budapest, Hungary as Kármán Tódor, studied engineering at the city's Royal Technical University, graduating in 1902. He then joined Ludwig Prandtl at ...

Including:

• Theodore von Kármán - Books

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Using the Scientific method, scientists set up experiments to determine causality in the physical world. Certain elemental forces such as gravity, the strong and weak nuclear forces, and electromagnetism are said to be the four fundamental forces which are the causes of all other events in the universe. However, the issue of to which degree a scientific experiment is replicable has been often raised but rarely addressed. The fact that no experime ...

See also:

Causality, Causality - Causation in the history of philosophy, Causality - Aristotle, Causality - Hume, Causality - Spinoza, Causality - Causality determinism and existentialism, Causality - Necessary and sufficient causes, Causality - Causality contrasted with logical implication, Causality - Counterfactual theories of causation, Causality - Probabilistic causation, Causality - Derivation theories, Causality - Manipulation theories, Causality - Process theories, Causality - Causality in psychology, Causality - Attribution, Causality - Causation and salience, Causality - Symbolism and causality, Causality - Causation in religion and theology, Causality - Cosmological argument, Causality - Karma, Causality - Reversed causality, Causality - Causality in science and the humanities, Causality - Physics, Causality - Engineering, Causality - History, Causality - Causality in law

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Neurofeedback (NFB), also called neurotherapy, neurobiofeedback or EEG biofeedback, enables an individual to train brainwave activity, as measured by electrodes on the scalp, via feedback of EEG information in the form of a video display, sound or vibration. If brain activity changes in the direction desired by the therapist, a positive "reward" feedback is given to the individual, and if it regresses, either a negative feedback or no feedback is given (depending on the protocol). Rewards can be as simple as a cha ...

Including:

• Neurofeedback - History and application
• Neurofeedback - Low Energy Neurofeedback System LENS
• Neurofeedback - Scientologists Parapsychologists and Less Mainstream Users of Neurofeedback

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The importance of finding a guru who can impart transcendental knowledge (vidya) is one of the tenets of Hinduism. One of the main Hindu texts, the Bhagavad Gita, is a dialogue between God in the form of Krishna and Arjuna a nobleman. Not only does their dialogue outlines many of the ideals of Hinduism, but the discussion and relationship between the two considered to be an expression of the ideal Guru/disciple relationship. In the Gita itself, Krishna speaks of the importance of finding a guru to Arjuna: Acquire the t ...

See also:

Guru, Guru - Etymology, Guru - Guru in Hinduism, Guru - Guru in Buddhism, Guru - Guru in Sikhism, Guru - Types of gurus, Guru - Succession and lineage parampara, Guru - Guru in a Western culture context, Guru - Gurus in the West, Guru - Assessment and criticism, Guru - Notable scandals and controversies, Guru - Bibliography

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Red hair is most commonly found at both the west and eastern fringes of modern Europe. Although red hair in the human population is most commonly associated with those of the British Isles (more specifically the Scots and Irish), dark red or reddish-tinged hair can be found in a few other Caucasian populations. The Galatian invasion of 275 BC has resulted in a smattering of red hair in the population of modern-day Turkey, as well as some in Iran. The Berber and Kabylie populations of northern Algeria have occasional red heads. The Classical Greek historian, Herodotus described his 'Budini' (probably Votyak a ...

See also:

Red hair, Red hair - Historical distribution, Red hair - Biochemistry and genetics of red hair, Red hair - Kwashiorkor condition, Red hair - Social implications, Red hair - Myths and stories related to red hair, Red hair - Notes

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The stigma surrounding the classification of a group as a cult stems from the purported ill effect the group's influence has on its members. The narratives of ill effect include threats presented by a cult to its members (whether real or perceived), and risks to the physical safety of its members and to their mental and spiritual growth. Much of the actions taken against cults and alleged cults have been in reaction to the harm experienced by some members due to their affiliation with the groups in question. Members of alleged ...

See also:

Cult, Cult - Definitions of cult, Cult - Definition of cult in dictionaries, Cult - Definition by the Christian countercult movement, Cult - Definition by secular cult opposition, Cult - Points of view regarding definitions, Cult - Cult NRM and the sociology and psychology of religion, Cult - Christianity and Cults, Cult - Cults and terrorism, Cult - Theories about the reasons for joining a cult, Cult - Cult leadership, Cult - Development of cults, Cult - Relationships with the outside world, Cult - Cults: genuine concerns and exaggerations, Cult - Stigmatization and discrimination, Cult - Leaving a cult, Cult - Criticism by former members of purported cults, Cult - Allegations made by scholars and skeptics, Cult - Other allegations, Cult - Prevalence of purported cults, Cult - Cults and governments, Cult - Bibliography, Cult - Books, Cult - Articles

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Consider a probability density functional P[X(s)] for stochastic variables X(s) at different points s of some space, then the correlation function is where the statistical averages are taken with respect to the measure specified by the probability density function. In this definition, it has been assumed that the stochastic variable is a scalar. If it is not, then one can define more complicated correlation functions. For example, if one has a vector Xi(s), then one can define the m ...

See also:

Correlation function, Correlation function - Definition, Correlation function - Properties of probability distributions

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As noted in the definition above two proportional variables are sometime said to be directly proportional. This is done so as to contrast proportionality with inverse proportionality. Two variables are inversely proportional (or varying inversely) if one of the variables is directly proportional with the multiplicative inverse of the other, or equivalently if their product is a constant. It follows, that the variable y is inversely proportional to the variable x if t ...

See also:

Proportionality mathematics, Proportionality mathematics - Definition, Proportionality mathematics - Examples, Proportionality mathematics - Properties, Proportionality mathematics - Inverse proportionality, Proportionality mathematics - Exponential and logarithmic proportionality, Proportionality mathematics - Experimental determination

Read more here: » Proportionality mathematics: Encyclopedia II - Proportionality mathematics - Inverse proportionality