Contents
| |||
|---|---|---|---|
| +... |
 | This article needs additional citations for verification .(February 2024) |
1904 in philosophy
| |||
|---|---|---|---|
| +... |
| | This article needs additional citations for verification .(February 2024) |
1904 in philosophy
 | This section is empty. You can help by adding to it. (February 2013) |
| | This section is empty. You can help by adding to it. (February 2013) |
| | This section is empty. You can help by adding to it. (February 2013) |
Burrhus Frederic Skinner was an American psychologist, behaviorist, inventor, and social philosopher. He was the Edgar Pierce Professor of Psychology at Harvard University from 1958 until his retirement in 1974.
Human skin color ranges from the darkest brown to the lightest hues. Differences in skin color among individuals is caused by variation in pigmentation, which is the result of genetics, exposure to the sun, disorders, or some combination thereof. Differences across populations evolved through natural selection or sexual selection, because of social norms and differences in environment, as well as regulations of the biochemical effects of ultraviolet radiation penetrating the skin.
Melanocytes are melanin-producing neural crest-derived cells located in the bottom layer of the skin's epidermis, the middle layer of the eye, the inner ear, vaginal epithelium, meninges, bones, and heart. Melanin is a dark pigment primarily responsible for skin color. Once synthesized, melanin is contained in special organelles called melanosomes which can be transported to nearby keratinocytes to induce pigmentation. Thus darker skin tones have more melanosomes present than lighter skin tones. Functionally, melanin serves as protection against UV radiation. Melanocytes also have a role in the immune system.
A skin tag, or acrochordon, is a small benign tumor that forms primarily in areas where the skin forms creases, such as the neck, armpit and groin. They may also occur on the face, usually on the eyelids. Though tags up to half an inch (12.7 mm) long have been seen, they are typically the size of a grain of rice. The surface of an acrochordon may be smooth or irregular in appearance and is often raised from the surface of the skin on a fleshy stalk called a peduncle. Microscopically, an acrochordon consists of a fibrovascular core, sometimes also with fat cells, covered by an unremarkable epidermis. However, tags may become irritated by shaving, clothing, jewellery, or eczema.
Vitiligo is a chronic autoimmune disorder that causes patches of skin to lose pigment or color. The cause of vitiligo is unknown, but it may be related to immune system changes, genetic factors, stress, or sun exposure. Treatment options include topical medications, light therapy, surgery and cosmetics. The condition can show up on any skin type as a light peachy color and can appear on any place on the body in all sizes. The spots on the skin known as vitiligo are also able to “change” as spots lose and regain pigment; they will stay in relatively the same areas but can move over time and some big patches can move through the years but never disappear overnight.
Psoriasis is a long-lasting, noncontagious autoimmune disease characterized by patches of abnormal skin. These areas are red, pink, or purple, dry, itchy, and scaly. Psoriasis varies in severity from small localized patches to complete body coverage. Injury to the skin can trigger psoriatic skin changes at that spot, which is known as the Koebner phenomenon.
Ehlers–Danlos syndromes (EDS) are a group of 13 genetic connective-tissue disorders. Symptoms often include loose joints, joint pain, stretchy velvety skin, and abnormal scar formation. These may be noticed at birth or in early childhood. Complications may include aortic dissection, joint dislocations, scoliosis, chronic pain, or early osteoarthritis. The current classification was last updated in 2017, when a number of rarer forms of EDS were added.
In electromagnetism, skin effect is the tendency of an alternating electric current (AC) to become distributed within a conductor such that the current density is largest near the surface of the conductor and decreases exponentially with greater depths in the conductor. It is caused by opposing eddy currents induced by the changing magnetic field resulting from the alternating current. The electric current flows mainly at the skin of the conductor, between the outer surface and a level called the skin depth. Skin depth depends on the frequency of the alternating current; as frequency increases, current flow becomes more concentrated near the surface, resulting in less skin depth. Skin effect reduces the effective cross-section of the conductor and thus increases its effective resistance. At 60 Hz in copper, skin depth is about 8.5 mm. At high frequencies, skin depth becomes much smaller.
The jungle cat, also called reed cat and swamp cat is a medium-sized cat native to the Middle East, the Caucasus, South and Southeast Asia and southern China. It inhabits foremost wetlands like swamps, littoral and riparian areas with dense vegetation. It is listed as Least Concern on the IUCN Red List, and is mainly threatened by destruction of wetlands, trapping and poisoning.
The morin khuur, also known as the horsehead fiddle, is a traditional Mongolian bowed stringed instrument. It is one of the most important musical instruments of the Mongol people, and is considered a symbol of the nation of Mongolia. The morin khuur is one of the Masterpieces of the Oral and Intangible Heritage of Humanity identified by UNESCO.
Behaviorism is a systematic approach to understand the behavior of humans and other animals. It assumes that behavior is either a reflex evoked by the pairing of certain antecedent stimuli in the environment, or a consequence of that individual's history, including especially reinforcement and punishment contingencies, together with the individual's current motivational state and controlling stimuli. Although behaviorists generally accept the important role of heredity in determining behavior, they focus primarily on environmental events. The cognitive revolution of the late 20th century largely replaced behaviorism as an explanatory theory with cognitive psychology, which unlike behaviorism examines internal mental states.
Acral lentiginous melanoma is a type of skin cancer. It typically begins as a uniform brownish mark before becoming darker and wider with a blurred irregular edge, most frequently seen in the foot of a person with darker skin. It may become bumpy and ulcerate. Just under the nail it typically appears as dark longitudinal streaks, and it may spread.
Incontinentia pigmenti (IP) is a rare X-linked dominant genetic disorder that affects the skin, hair, teeth, nails and central nervous system. It is named from its appearance under a microscope.
Chytridiomycosis is an infectious disease in amphibians, caused by the chytrid fungi Batrachochytrium dendrobatidis and Batrachochytrium salamandrivorans. Chytridiomycosis has been linked to dramatic population declines or extinctions of amphibian species in western North America, Central America, South America, eastern Australia, east Africa (Tanzania), and Dominica and Montserrat in the Caribbean. Much of the New World is also at risk of the disease arriving within the coming years. The fungus is capable of causing sporadic deaths in some amphibian populations and 100% mortality in others. No effective measure is known for control of the disease in wild populations. Various clinical signs are seen by individuals affected by the disease. A number of options are possible for controlling this disease-causing fungus, though none has proved to be feasible on a large scale. The disease has been proposed as a contributing factor to a global decline in amphibian populations that apparently has affected about 30% of the amphibian species of the world. Some research found evidence insufficient for linking chytrid fungi and chytridiomycosis to global amphibian declines, but more recent research establishes a connection and attributes the spread of the disease to its transmission through international trade routes into native ecosystems.
The European wildcat is a small wildcat species native to continental Europe, Scotland, Turkey and the Caucasus. It inhabits forests from the Iberian Peninsula, Italy, Central and Eastern Europe to the Caucasus. Its fur is brownish to grey with stripes on the forehead and on the sides and has a bushy tail with a black tip. It reaches a head-to-body length of up to 65 cm (26 in) with a 34.5 cm (13.6 in) long tail, and weighs up to 7.5 kg (17 lb).
Chlormezanone is a drug used as an anxiolytic and a muscle relaxant.
The African wildcat is a small wildcat species with sandy grey fur, pale vertical stripes on the sides and around the face. It is native to Africa, West and Central Asia, and is distributed to Rajasthan in India and Xinjiang in China. It inhabits a broad variety of landscapes ranging from deserts to savannas, shrublands and grasslands.
Ogden R. Lindsley was an American psychologist. He is best known for developing precision teaching.
Inhibitor of nuclear factor kappa-B kinase subunit alpha (IKK-α) also known as IKK1 or conserved helix-loop-helix ubiquitous kinase (CHUK) is a protein kinase that in humans is encoded by the CHUK gene. IKK-α is part of the IκB kinase complex that plays an important role in regulating the NF-κB transcription factor. However, IKK-α has many additional cellular targets, and is thought to function independently of the NF-κB pathway to regulate epidermal differentiation.
Lucius Duncan Bulkley was an American dermatologist and alternative cancer treatment advocate.