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Topic Review
Vestigiality
Vestigiality is the retention during the process of evolution of genetically determined structures or attributes that have lost some or all of the ancestral function in a given species. Assessment of the vestigiality must generally rely on comparison with homologous features in related species. The emergence of vestigiality occurs by normal evolutionary processes, typically by loss of function of a feature that is no longer subject to positive selection pressures when it loses its value in a changing environment. The feature may be selected against more urgently when its function becomes definitively harmful, but if the lack of the feature provides no advantage, and its presence provides no disadvantage, the feature may not be phased out by natural selection and persist across species. Examples of vestigial structures (also called degenerate, atrophied, or rudimentary organs) are the loss of functional wings in island-dwelling birds; the human vomeronasal organ; and the hindlimbs of the snake and whale. The human appendix is no longer considered vestigial.
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  • 24 Oct 2022
Biography
William Thomson, Baron Kelvin
William Thomson, Baron Kelvin, OM, GCVO, PC, PRS, FRSE (26 June 1824 – 17 December 1907) was a British[1] mathematical physicist and engineer who was born in Belfast in 1824. At the University of Glasgow he did important work in the mathematical analysis of electricity and formulation of the first and second laws of thermodynamics, and did much to unify the emerging discipline of physics in it
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  • 01 Dec 2022
Biography
Bill Donohue
William Anthony Donohue (born July 18, 1947) is an American Roman Catholic. He has been president of the Catholic League in the United States since 1993.[1] Donohue was born in the borough of Manhattan in New York City , New York. He began his teaching career in the 1970s working at St. Lucy's School in Spanish Harlem. In 1977, he took a teaching position at La Roche College in McCandless, Pe
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  • 30 Dec 2022
Topic Review
Marsupial Lion
The marsupial lion (Thylacoleo carnifex) is an extinct species of carnivorous marsupial mammal that lived in Australia from the early to the late Pleistocene (1,600,000–46,000 years ago). Despite its name, it is not closely related to the lion, but is a member of the order Diprotodontia, one of the taxonomic groups of Australian marsupials.
  • 3.3K
  • 20 Oct 2022
Topic Review
Pudu (Genus)
The pudus (Mapudungun püdü or püdu, Spanish: pudú, Spanish pronunciation: [puˈðu]) are two species of South American deer from the genus Pudu, and are the world's smallest deer. The name is a loanword from Mapudungun, the language of the indigenous Mapuche people of central Chile and south-western Argentina. The two species of pudus are the northern pudu (Pudu mephistophiles) from Venezuela, Colombia, Ecuador, and Peru, and the southern pudu (Pudu puda; sometimes incorrectly modified to Pudu pudu) from southern Chile and south-western Argentina . Pudus range in size from 32 to 44 centimeters (13 to 17 in) tall, and up to 85 centimeters (33 in) long. The southern pudu is currently classified as near threatened, while the northern pudu is classified as Data Deficient in the IUCN Red List.
  • 3.3K
  • 20 Oct 2022
Topic Review
Evolution of Domestic Goats
Goat evolution is the process by which domestic goats came to exist through evolution by natural selection. Wild goats — medium-sized mammals which are found in noticeably harsh environments, particularly forests and mountains, in the Middle East and Central Asia — were one of the first species domesticated by modern humans, with the date of domestication generally considered to be 8,000 BCE. Goats are part of the family Bovidae, a broad and populous group which includes a variety of ruminants such as bison, cows and sheep. Bovids all share many traits, such as hooves and a herbivorous diet and all males, along with many females, have horns. Bovids began to diverge from deer and giraffids during the early Miocene epoch. The subfamily Caprinae, which includes goats, ibex and sheep, are considered to have diverged from the rest of Bovidae as early as the late Miocene, with the group reaching its greatest diversity in the ice ages. The tribe Caprini would subsequently develop from Caprids who arrived in the mountainous areas of Eurasia and split into goats and sheep in response to a further geographic separation. The ancestors of sheep remained in the foothills and the ancestors of goats went to higher altitudes. This divergence resulted in the adaption of the ancestors of goats to a mountainous environment, producing many of the traits considered peculiar to the species. During the ice ages a genus called Capri evolved which would then diverge into the modern goat species, along with several species of ibex. It is commonly held that the earliest domestication was of the bezoar ibex in the Zagros Mountains. These earliest domesticated goats were used to produce meat and milk for Neolithic farmers, along with providing many of the materials required to built residences and tools. Following the domestication of goats over 300 breeds have been established for a variety of purposes, including for the maximation of milk production and for meat. Domestication and the selective breeding which resulted had a significant effect on the direction of goat evolution, with goats developing behaviour which is considered to have been influenced by consistent proximity to humans. Selective breeding also significantly increased the physical diversity of modern goats, producing characteristics not seen in wild goats.
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  • 08 Oct 2023
Topic Review
Level of Consciousness (Esotericism)
Consciousness is a loosely defined concept that addresses the human awareness of both internal and external stimuli. This can refer to spiritual recognition, psychological understanding, medically altered states, or more modern-day concepts of life purpose, satisfaction, and self-actualization. Levels of Consciousness can be presented in a map. Some levels are more continuous or complex than others. Movement between levels or stages is often bidirectional depending on internal and external conditions, with each mental ascension precipitating a change in reactivity. In the most basic sense, this alteration might lead to a reduced responsiveness as seen in anesthesiology; more abstract facets of tiered consciousness describe characteristics of profoundness, insight, perception, or understanding. First appearing in the historical records of the ancient Mayan and Incan civilizations, proposals of multiple levels of consciousness have pervaded spiritual, psychological, medical, and moral speculations in both Eastern and Western cultures. Because of occasional and sometimes substantial overlap between hypotheses, there have recently been attempts to combine perspectives to form new models that integrate components of separate viewpoints. Any of these proposals, models or viewpoints can be verified or falsified, and are open to question.
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  • 24 Nov 2022
Topic Review
Physaliidae
The Portuguese man o' war (Physalia physalis), also known as the man-of-war, bluebottle, blue bottle jellyfish, or floating terror is a marine hydrozoan found in the Atlantic Ocean and the Indian Ocean. It is considered to be the same species as the Pacific man o' war, which is found mainly in the Pacific Ocean. The Portuguese man o' war is the only species in the genus Physalia, which in turn is the only genus in the family Physaliidae. It has numerous venomous microscopic nematocysts which deliver a painful sting powerful enough to kill fish, and has been known to occasionally kill humans. Although it superficially resembles a jellyfish, the Portuguese man o' war is in fact a siphonophore. Like all siphonophores, it is a colonial organism, made up of many smaller units called zooids. All zooids in a colony are genetically identical, but fulfill specialized functions such as feeding and reproduction, and together allow the colony to operate as a single individual.
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  • 27 Oct 2022
Biography
Arthur B. C. Walker Jr.
Arthur Bertram Cuthbert Walker Jr. (August 24, 1936 – April 29, 2001) was a solar physicist and a pioneer of EUV/XUV optics. He is most noted for having developed normal incidence multilayer XUV telescopes to photograph the solar corona. Two of his sounding rocket payloads, the Stanford/MSFC Rocket Spectroheliograph Experiment and the Multi-Spectral Solar Telescope Array, recorded the first fu
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  • 08 Dec 2022
Topic Review
Tissues to Implant Abutments
This entry is based on the fact that physical or biomechanical phenomena can cause biologic results. Implant-abutment connection structures determine the stability of soft tissue attachment to abutments. The bone responses to the strain that the stress is converted to, not the stress itself. Some implant-abutment materials and connection designs prevent the marginal bone loss by converting the stress to the strain stimulating bone apposition properly. These biomechanical interpretation of soft tissue seal and bone stimulation should be understood for the clinical long-term success of dental implants.
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  • 27 Oct 2020
Topic Review
Giant Cheetah
The giant cheetah (Acinonyx pardinensis) is an extinct felid species that was closely related to the modern cheetah.
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  • 14 Oct 2022
Topic Review
Explicit Memory
Explicit memory (or declarative memory) is one of the two main types of long-term human memory, the other of which is implicit memory. Explicit memory is the conscious, intentional recollection of factual information, previous experiences, and concepts. This type of memory is dependent upon three processes: acquisition, consolidation, and retrieval. Explicit memory can be divided into two categories: episodic memory, which stores specific personal experiences, and semantic memory, which stores factual information. Explicit memory requires gradual learning, with multiple presentations of a stimulus and response. Procedural memory, a type of implicit (or non-declarative) memory, refers to unconscious memories such as skills (e.g. knowing how to get dressed, eat, drive, ride a bicycle without having to re-learn the skill each time). Procedural memory learns rule-like relations, whereas explicit memory learns relations that are arbitrary. Unlike explicit memory, procedural memory learns rapidly, even from a single stimulus, and it is influenced by other mental systems. Sometimes a distinction is made between explicit memory and declarative memory. In such cases, explicit memory relates to any kind of conscious memory, and declarative memory relates to any kind of memory that can be described in words; however, if it is assumed that a memory cannot be described without being conscious and vice versa, then the two concepts are identical.
  • 3.2K
  • 23 Nov 2022
Biography
Gregory Benford
Gregory Benford (born January 30, 1941) is an American science fiction author and astrophysicist who is on the faculty of the Department of Physics and Astronomy at the University of California, Irvine. He is also a contributing editor of Reason magazine.[1] As a science fiction author, Benford is perhaps best known for the Galactic Center Saga novels, beginning with In the Ocean of Night (1977
  • 3.2K
  • 05 Dec 2022
Topic Review
Plesiosauria
The Plesiosauria (/ˌpliːsiəˈsɔːriə, -zi-/; Greek: πλησίος, plesios, meaning "near to" and sauros, meaning "lizard") or plesiosaurs are an order or clade of extinct Mesozoic marine reptiles, belonging to the Sauropterygia. Plesiosaurs first appeared in the latest Triassic Period, possibly in the Rhaetian stage, about 203 million years ago. They became especially common during the Jurassic Period, thriving until their disappearance due to the Cretaceous–Paleogene extinction event at the end of the Cretaceous Period, about 66 million years ago. They had a worldwide oceanic distribution. Plesiosaurs were among the first fossil reptiles discovered. In the beginning of the nineteenth century, scientists realised how distinctive their build was and they were named as a separate order in 1835. The first plesiosaurian genus, the eponymous Plesiosaurus, was named in 1821. Since then, more than a hundred valid species have been described. In the early twenty-first century, the number of discoveries has increased, leading to an improved understanding of their anatomy, relationships and way of life. Plesiosaurs had a broad flat body and a short tail. Their limbs had evolved into four long flippers, which were powered by strong muscles attached to wide bony plates formed by the shoulder girdle and the pelvis. The flippers made a flying movement through the water. Plesiosaurs breathed air, and bore live young; there are indications that they were warm-blooded. Plesiosaurs showed two main morphological types. Some species, with the "plesiosauromorph" build, had (sometimes extremely) long necks and small heads; these were relatively slow and caught small sea animals. Other species, some of them reaching a length of up to seventeen metres, had the "pliosauromorph" build with a short neck and a large head; these were apex predators, fast hunters of large prey. The two types are related to the traditional strict division of the Plesiosauria into two suborders, the long-necked Plesiosauroidea and the short-neck Pliosauroidea. Modern research, however, indicates that several "long-necked" groups might have had some short-necked members or vice versa. Therefore, the purely descriptive terms "plesiosauromorph" and "pliosauromorph" have been introduced, which do not imply a direct relationship. "Plesiosauroidea" and "Pliosauroidea" today have a more limited meaning. The term "plesiosaur" is properly used to refer to the Plesiosauria as a whole, but informally it is sometimes meant to indicate only the long-necked forms, the old Plesiosauroidea.
  • 3.2K
  • 29 Nov 2022
Topic Review
Nikolaas Tinbergen
Nikolaas "Niko" Tinbergen FRS (/ˈtɪnbɜːrɡən/; Dutch: [ˈnikoːlaːs ˈnikoː ˈtɪnbɛrɣən]; 15 April 1907 – 21 December 1988) was a Dutch biologist and ornithologist who shared the 1973 Nobel Prize in Physiology or Medicine with Karl von Frisch and Konrad Lorenz for their discoveries concerning organization and elicitation of individual and social behavior patterns in animals. He is regarded as one of the founders of modern ethology, the study of animal behavior. In 1951, he published The Study of Instinct, an influential book on animal behaviour. In the 1960s, he collaborated with filmmaker Hugh Falkus on a series of wildlife films, including The Riddle of the Rook (1972) and Signals for Survival (1969), which won the Italia prize in that year and the American blue ribbon in 1971.
  • 3.2K
  • 04 Oct 2022
Biography
Karl Schwarzschild
Karl Schwarzschild (9 October 1873 – 11 May 1916) was a Germany physicist and astronomer. He was also the father of astrophysicist Martin Schwarzschild. Schwarzschild provided the first exact solution to the Einstein field equations of general relativity, for the limited case of a single spherical non-rotating mass, which he accomplished in 1915, the same year that Einstein first introduced g
  • 3.2K
  • 01 Dec 2022
Biography
George Marshall
General of the Army George Catlett Marshall Jr. (December 31, 1880 – October 16, 1959) was an American soldier and statesman. He rose through the United States Army to become Chief of Staff under presidents Franklin D. Roosevelt and Harry S. Truman, then served as Secretary of State and Secretary of Defense under Truman.[1] Winston Churchill lauded Marshall as the "organizer of victory" for hi
  • 3.2K
  • 15 Nov 2022
Biography
Edip Yüksel
Edip Yüksel (born December 20, 1957 in Güroymak, Turkey) is a Kurdish American author and philosophy professor of Sunni Muslim background. He is an exponent of the modern Islamic reform and Quranism (Quraniyoon) movements and is known for his criticism and rejection of both Sunni and Shiite versions of Islam. Author of several books on the Qur'an and Islam, he gained attention through his work
  • 3.2K
  • 01 Dec 2022
Topic Review
Autobiographical Memory
Autobiographical memory is a memory system consisting of episodes recollected from an individual's life, based on a combination of episodic (personal experiences and specific objects, people and events experienced at particular time and place) and semantic (general knowledge and facts about the world) memory. It is thus a type of explicit memory.
  • 3.1K
  • 28 Nov 2022
Topic Review
Oldest People
This is a list of tables of the oldest people in the world in ordinal ranks. To avoid including false or unconfirmed claims of extreme old age, names here are restricted to those people whose ages have been validated by an international body that specifically deals in longevity research, such as the Gerontology Research Group (GRG) or Guinness World Records (GWR), and others who have otherwise been reliably sourced. According to this criterion, the longest human lifespan is that of Jeanne Calment of France (1875–1997), who lived to the age of 122 years, 164 days. She met Vincent van Gogh when she was 12 or 13. She received news media attention in 1985, after turning 110. Subsequent investigation found documentation for Calment's age, beyond any reasonable question, in the records of her native city, Arles, France. More evidence of Calment's lifespan has been produced than for any other supercentenarian, such that her case serves as an archetype in the methodology for verifying the ages of the world's oldest people. As women live longer than men on average, combined records for both sexes are predominated by women. The longest undisputed lifespan for a man is that of Jiroemon Kimura of Japan (1897–2013), who died at age 116 years, 54 days. Since the death of 117-year-old Chiyo Miyako of Japan on 22 July 2018, 115-year-old Kane Tanaka, also of Japan, born 2 January 1903, is the oldest living person in the world whose age has been documented. Since the death of 113-year-old Francisco Núñez Olivera of Spain on 29 January 2018, 113-year-old Masazō Nonaka of Japan, born 25 July 1905, is the world's oldest verified living man.
  • 3.1K
  • 30 Nov 2022
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