You're using an outdated browser. Please upgrade to a modern browser for the best experience.
Subject:
All Disciplines Arts & Humanities Biology & Life Sciences Business & Economics Chemistry & Materials Science Computer Science & Mathematics Engineering Environmental & Earth Sciences Medicine & Pharmacology Physical Sciences Public Health & Healthcare Social Sciences
Sort by:
Most Viewed Latest Alphabetical (A-Z) Alphabetical (Z-A)
Filter:
All Topic Review Biography Peer Reviewed Entry Video Entry
Topic Review
Lories and Lorikeets
Lories and lorikeets (tribe Loriini) are small to medium-sized arboreal parrots characterized by their specialized brush-tipped tongues for feeding on nectar of various blossoms and soft fruits, preferably berries. The species form a monophyletic group within the parrot family Psittacidae. Traditionally, they were considered a separate subfamily (Loriinae) from the other subfamily (Psittacinae) based on the specialized characteristics, but recent molecular and morphological studies show that the group is positioned in the middle of various other groups. They are widely distributed throughout the Australasian region, including south-eastern Asia, Polynesia, Papua New Guinea, Timor Leste and Australia , and the majority have very brightly coloured plumage.
  • 3.1K
  • 21 Oct 2022
Topic Review
Red Queen Hypothesis
The Red Queen hypothesis is a hypothesis in evolutionary biology proposed in 1973, that species must constantly adapt, evolve, and proliferate in order to survive while pitted against ever-evolving opposing species. The hypothesis was intended to explain the constant (age-independent) extinction probability as observed in the paleontological record caused by co-evolution between competing species; however, it has also been suggested that the Red Queen hypothesis explains the advantage of sexual reproduction (as opposed to asexual reproduction) at the level of individuals, and the positive correlation between speciation and extinction rates in most higher taxa.
  • 3.1K
  • 22 Nov 2022
Biography
Neil Peart
Neil Ellwood Peart OC (/pɪərt/; September 12, 1952 – January 7, 2020) was a Canadian musician, songwriter, and author, best known as the drummer and primary lyricist of the rock band Rush. Peart earned numerous awards for his musical performances, including an induction into the Modern Drummer Readers Poll Hall of Fame in 1983, making him the youngest person ever so honoured.[1] His drumming
  • 3.1K
  • 16 Nov 2022
Topic Review
Glossitis Areata Exfoliativa
Geographic tongue, also known by several other terms, is a condition of the mucous membrane of the tongue, usually on the dorsal surface. It is a common condition, affecting approximately 2–3% of the general population. It is characterized by areas of smooth, red depapillation (loss of lingual papillae) which migrate over time. The name comes from the map-like appearance of the tongue, with the patches resembling the islands of an archipelago. The cause is unknown, but the condition is entirely benign (importantly, it does not represent oral cancer), and there is no curative treatment. Uncommonly, geographic tongue may cause a burning sensation on the tongue, for which various treatments have been described with little formal evidence of efficacy.
  • 3.1K
  • 24 Oct 2022
Biography
David Abram
David Abram (born June 24, 1957) is an American philosopher, cultural ecologist, and performance artist, best known for his work bridging the philosophical tradition of phenomenology with environmental and ecological issues.[1][2] He is the author of Becoming Animal: An Earthly Cosmology[3] (2010) and The Spell of the Sensuous: Perception and Language in a More-than-Human World (1996), for which
  • 3.1K
  • 12 Dec 2022
Topic Review
Helleborus
Commonly known as hellebores (/ˈhɛlɪbɔːrz/), the Eurasian genus Helleborus consists of approximately 20 species of herbaceous or evergreen perennial flowering plants in the family Ranunculaceae, within which it gave its name to the tribe of Helleboreae. Despite names such as "winter rose", "Christmas rose" and "Lenten rose", hellebores are not closely related to the rose family (Rosaceae). Many hellebore species are poisonous.
  • 3.1K
  • 24 Nov 2022
Topic Review
Actinopterygii
Actinopterygii (/ˌæktɪnɒptəˈrɪdʒiaɪ/; from actino- 'having rays', and grc πτέρυξ (ptérux) 'wing, fins'), members of which are known as ray-finned fishes, is a clade (traditionally class or subclass) of the bony fishes. They comprise over 50% of living vertebrate species. The ray-finned fishes are so-called because their fins are webs of skin supported by bony or horny spines (rays), as opposed to the fleshy, lobed fins that characterize the class Sarcopterygii (lobe-finned fish). These actinopterygian fin rays attach directly to the proximal or basal skeletal elements, the radials, which represent the link or connection between these fins and the internal skeleton (e.g., pelvic and pectoral girdles). By species count, actinopterygians dominate the vertebrates, and they comprise nearly 99% of the over 30,000 species of fish. They are ubiquitous throughout freshwater and marine environments from the deep sea to the highest mountain streams. Extant species can range in size from Paedocypris, at 8 mm (0.3 in), to the massive ocean sunfish, at 2,300 kg (5,070 lb), and the long-bodied oarfish, at 11 m (36 ft). The vast majority of Actinopterygii (~95%) are teleosts.
  • 3.1K
  • 27 Oct 2022
Topic Review
Duck
Duck is the common name for numerous species in the waterfowl family Anatidae which also includes swans and geese. Ducks are divided among several subfamilies in the family Anatidae; they do not represent a monophyletic group (the group of all descendants of a single common ancestral species) but a form taxon, since swans and geese are not considered ducks. Ducks are mostly aquatic birds, mostly smaller than the swans and geese, and may be found in both fresh water and sea water. Ducks are sometimes confused with several types of unrelated water birds with similar forms, such as loons or divers, grebes, gallinules and coots.
  • 3.1K
  • 18 Oct 2022
Topic Review
Cardiolipin
Cardiolipin (IUPAC name 1,3-bis(sn-3’-phosphatidyl)-sn-glycerol) is an important component of the inner mitochondrial membrane, where it constitutes about 20% of the total lipid composition. It can also be found in the membranes of most bacteria. The name "cardiolipin" is derived from the fact that it was first found in animal hearts. It was first isolated from beef heart in the early 1940s. In mammalian cells, but also in plant cells, cardiolipin (CL) is found almost exclusively in the inner mitochondrial membrane, where it is essential for the optimal function of numerous enzymes that are involved in mitochondrial energy metabolism.
  • 3.0K
  • 28 Sep 2022
Biography
Ishfaq Ahmad
Ishfaq Ahmad, D.Sc., Minister of State, SI, HI, NI, FPAS (3 November 1930 – 18 January 2018), was a Pakistani nuclear physicist, emeritus professor of high-energy physics at the National Center for Physics, and former science advisor to the Government of Pakistan.[1] A versatile theoretical physicist,[2] Ahmad made significant contributions in the theoretical development of the applications a
  • 3.0K
  • 15 Nov 2022
Topic Review
Sponge
Sponges, the members of the phylum Porifera (/pəˈrɪfərə/; meaning 'pore bearer'), are a basal animal clade as a sister of the diploblasts. They are multicellular organisms that have bodies full of pores and channels allowing water to circulate through them, consisting of jelly-like mesohyl sandwiched between two thin layers of cells. Sponges have unspecialized cells that can transform into other types and that often migrate between the main cell layers and the mesohyl in the process. Sponges do not have nervous, digestive or circulatory systems. Instead, most rely on maintaining a constant water flow through their bodies to obtain food and oxygen and to remove wastes. Sponges were first to branch off the evolutionary tree from the last common ancestor of all animals, making them the sister group of all other animals.
  • 3.0K
  • 22 Nov 2022
Topic Review
Australian Raven
The Australian raven (Corvus coronoides) is a passerine bird in the genus Corvus native to much of southern and northeastern Australia. Measuring 46–53 centimetres (18–21 in) in length, it has all-black plumage, beak and mouth, as well as strong grey-black legs and feet. The upperparts are glossy, with a purple, blue, or green sheen, and its black feathers have grey bases. The Australian raven is distinguished from the Australian crow species by its throat hackles, which are prominent in adult birds. Older adult individuals have white irises, younger adults have white irises with an inner blue rim, while younger birds have dark brown irises until fifteen months of age, and hazel irises with an inner blue rim around each pupil until age two years and ten months. Nicholas Aylward Vigors and Thomas Horsfield described the Australian raven in 1827, its species name (coronoides) highlighting its similarity with the carrion crow (C. corone). Two subspecies are recognized, which differ slightly in calls and are quite divergent genetically. The preferred habitat is open woodland and transitional zones. It has adapted well to urban environments and is a common city bird in Sydney, Canberra, and Perth. An omnivorous and opportunistic feeder, it eats a wide variety of plant and animal material, as well as food waste from urban areas. In eastern Australia, its range is strongly correlated with the presence of sheep, and it has been blamed for killing lambs. However, this is very rare, and the raven most often scavenges for afterbirth and stillborn animals as well as newborn lamb faeces. The Australian raven is territorial, with pairs generally bonding for life. Breeding takes place between July and September, with almost no variation across its range. The nest is a bowl-shaped structure of sticks sited high in a tree, or occasionally in a man-made structure such as a windmill or other building. File:An audio recording of an Australian Raven (Corvus coronoides).wav
  • 3.0K
  • 21 Nov 2022
Topic Review
Monkeys in Chinese Culture
Monkeys, particularly macaques and monkey-like gibbons, have played significant roles in Chinese culture for over two thousand years. Some examples familiar to English speakers include the zodiacal Year of the Monkey, the Monkey King Sun Wukong in the novel Journey to the West, and Monkey Kung Fu.
  • 3.0K
  • 25 Nov 2022
Biography
Juan Martín Maldacena
Juan Martín Maldacena (September 10, 1968 ) is an Argentine theoretical physicist and the Carl P. Feinberg Professor in the School of Natural Sciences at the Institute for Advanced Study.[1] He has made significant contributions to the foundations of string theory and quantum gravity. His most famous discovery is the AdS/CFT correspondence, a realization of the holographic principle in string t
  • 3.0K
  • 24 Nov 2022
Topic Review
Eurypterida
Eurypterids, often informally called sea scorpions, are a group of extinct arthropods that form the order Eurypterida. The earliest known eurypterids date to the Darriwilian stage of the Ordovician period 467.3 million years ago. The group is likely to have appeared first either during the Early Ordovician or Late Cambrian period. With approximately 250 species, the Eurypterida is the most diverse Paleozoic chelicerate order. Following their appearance during the Ordovician, eurypterids became major components of marine faunas during the Silurian, from which the majority of eurypterid species have been described. The Silurian genus Eurypterus accounts for more than 90% of all known eurypterid specimens. Though the group continued to diversify during the subsequent Devonian period, the eurypterids were heavily affected by the Late Devonian extinction event. They declined in numbers and diversity until becoming extinct during the Permian–Triassic extinction event (or sometime shortly before) 251.9 million years ago. Although popularly called "sea scorpions", only the earliest eurypterids were marine; many later forms lived in brackish or fresh water, and they were not true scorpions. Some studies suggest that a dual respiratory system was present, which would have allowed for short periods of time in terrestrial environments. The name Eurypterida comes from the Ancient Greek words εὐρύς (eurús), meaning 'broad' or 'wide', and πτερόν (pterón), meaning 'wing', referring to the pair of wide swimming appendages present in many members of the group. The eurypterids include the largest known arthropods ever to have lived. The largest, Jaekelopterus, reached 2.5 meters (8.2 ft) in length. Eurypterids were not uniformly large and most species were less than 20 centimeters (8 in) long; the smallest eurypterid, Alkenopterus, was only 2.03 centimeters (0.80 in) long. Eurypterid fossils have been recovered from every continent. A majority of fossils are from fossil sites in North America and Europe because the group lived primarily in the waters around and within the ancient supercontinent of Euramerica. Only a handful of eurypterid groups spread beyond the confines of Euramerica and a few genera, such as Adelophthalmus and Pterygotus, achieved a cosmopolitan distribution with fossils being found worldwide.
  • 3.0K
  • 25 Nov 2022
Biography
Beatrice Wood
Beatrice Wood (March 3, 1893 – March 12, 1998) was an United States artist and studio potter involved in the Avant Garde movement in the United States; she founded and edited The Blind Man magazine in New York City with French artist Marcel Duchamp and writer Henri-Pierre Roché in 1917.[1] She had earlier studied art and theater in Paris, and was working in New York as an actress. She later w
  • 3.0K
  • 25 Nov 2022
Biography
Harold G. White
Harold G. "Sonny" White is a mechanical engineer, aerospace engineer and applied physicist who is the Advanced Propulsion Team Lead for the NASA Engineering Directorate and is known for proposing new Alcubierre drive concepts and promoting advanced propulsion projects, under development at the NASA Johnson Space Center, including the first practical experiment to test the existence of Alcubierre
  • 2.9K
  • 17 Nov 2022
Topic Review
Long-Term Memory
Long-term memory (LTM) is the stage of the Atkinson–Shiffrin memory model in which informative knowledge is held indefinitely. It is defined in contrast to short-term and working memory, which persist for only about 18 to 30 seconds. Long-term memory is commonly labelled as explicit memory (declarative), as well as episodic memory, semantic memory, autobiographical memory, and implicit memory (procedural memory).
  • 2.9K
  • 24 Nov 2022
Topic Review
Gravitational Influence
Gravity constituted the only constant environmental parameter, during the evolutionary period of living matter on Earth. However, whether gravity has affected the evolution of species, and its impact is still ongoing.
  • 2.9K
  • 14 Jul 2021
Topic Review
Cat Senses
Cat senses are adaptations that allow cats to be highly efficient predators. Cats are good at detecting movement in low light, have an acute sense of hearing and smell, and their sense of touch is enhanced by long whiskers that protrude from their heads and bodies. These senses evolved to allow cats to hunt effectively at night.
  • 2.9K
  • 09 Nov 2022
  • Page
  • of
  • 68
Featured Entry Collections
>>

Featured Books

>>
Encyclopedia of COVID-19
Encyclopedia of Engineering
Encyclopedia of Social Sciences
Encyclopedia of Digital Society, Industry 5.0 and Smart City
Academic Video Service
Feedback