Your browser does not fully support modern features. Please upgrade for a smoother 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
Addax
The addax (Addax nasomaculatus), also known as the white antelope and the screwhorn antelope, is an antelope native to the Sahara Desert. The only member of the genus Addax, it was first described scientifically by Henri de Blainville in 1816. As suggested by its alternative name, the pale antelope has long, twisted horns - typically 55 to 80 cm (22 to 31 in) in females and 70 to 85 cm (28 to 33 in) in males. Males stand from 105 to 115 cm (41 to 45 in) at the shoulder, with females at 95 to 110 cm (37 to 43 in). They are sexually dimorphic, as the females are smaller than the males. The colour of the coat depends on the season - in the winter, it is greyish-brown with white hindquarters and legs, and long, brown hair on the head, neck, and shoulders; in the summer, the coat turns almost completely white or sandy blonde. The addax mainly eats grasses and leaves of any available shrubs, leguminous herbs and bushes. They are well-adapted to exist in their desert habitat, as they can live without water for long periods of time. Addax form herds of five to 20 members, consisting of both males and females. They are led by the oldest female. Due to its slow movements, the addax is an easy target for its predators: humans, lions, leopards, cheetahs and African wild dogs. Breeding season is at its peak during winter and early spring. The natural habitat of the addax are arid regions, semideserts and sandy and stony deserts. The addax is a critically endangered species of antelope, as classified by the IUCN. Although extremely rare in its native habitat due to unregulated hunting, it is quite common in captivity. The addax was once abundant in North Africa; however it is currently only native to Chad, Mauritania, and Niger. It is extirpated from Algeria, Egypt, Libya, Sudan, and Western Sahara, but has been reintroduced into Morocco and Tunisia.
  • 1.8K
  • 14 Oct 2022
Topic Review
Taenia (Cestode)
Taenia is a genus of tapeworms (a type of helminth) that includes some important parasites of livestock. Members of the genus are responsible for taeniasis and cysticercosis in humans, which are a type of helminthiasis belonging to the group of neglected tropical diseases. More than 100 species are recorded. They are morphologically characterized by a ribbon-like body composed of a series of segments called proglottids; hence the name Taenia (Greek ταίνια, tainia meaning ribbon, bandage, or stripe). The anterior end of the body is the scolex. Not all members of the genus Taenia have an armed scolex (hooks and/or spines located in the "head" region), for example, Taenia saginata has an unarmed scolex, while Taenia solium has an armed scolex. Proglottids have a central ovary, with a vitellarium (yolk gland) posterior to it. As in all cyclophyllid cestodes, a genital pore occurs on the side of the proglottid. Eggs are released when the proglottid deteriorates, so a uterine pore is unnecessary.
  • 1.8K
  • 22 Nov 2022
Topic Review
Iconic Memory
Iconic memory is the visual sensory memory register pertaining to the visual domain and a fast-decaying store of visual information. It is a component of the visual memory system which also includes visual short-term memory (VSTM) and long-term memory (LTM). Iconic memory is described as a very brief (
  • 1.8K
  • 07 Oct 2022
Topic Review
Deinonychosauria
Deinonychosauria is a probable stem-bird clade of maniraptoran dinosaurs that lived from the Late Jurassic to the Late Cretaceous periods. Fossils have been found across the globe in North America, Europe, Africa, Japan , China , Mongolia, Manchuria, Madagascar , Argentina , and Antarctica, with fossilized teeth giving credence to the possibility that they inhabited Australia as well. This group of dinosaurs are known for their sickle-shaped toe claws and features in the shoulder bones.
  • 1.8K
  • 24 Oct 2022
Topic Review
Blister
A blister is a small pocket of body fluid (lymph, serum, plasma, blood, or pus) within the upper layers of the skin, usually caused by forceful rubbing (friction), burning, freezing, chemical exposure or infection. Most blisters are filled with a clear fluid, either serum or plasma. However, blisters can be filled with blood (known as "blood blisters") or with pus (for instance, if they become infected). The word "blister" entered English in the 14th century. It came from the Middle Dutch bluyster and was a modification of the Old French blostre, which meant a leprous nodule—a rise in the skin due to leprosy. In dermatology today, the words vesicle and bulla refer to blisters of smaller or greater size, respectively. To heal properly, a blister should not be popped unless medically necessary. If popped, the excess skin should not be removed because the skin underneath needs the top layer to heal properly.
  • 1.8K
  • 09 Nov 2022
Biography
Wolfgang Gentner
Wolfgang Gentner (23 July 1906 in Frankfurt am Main – 4 September 1980 in Heidelberg)[1] was a German experimental nuclear physicist. Gentner received his doctorate in 1930 from the University of Frankfurt. From 1932 to 1935 he had a fellowship which allowed him to do postdoctoral research and study at Curie's Radium Institute at the University of Paris. From 1936 to 1945, he was a staff scie
  • 1.8K
  • 14 Dec 2022
Topic Review
Occipital Epilepsy
Occipital epilepsy is a neurological disorder that arises from excessive neural activity in the occipital lobe of the brain that may or may not be symptomatic. Occipital lobe epilepsy is fairly rare, and may sometimes be misdiagnosed as migraine when symptomatic. Epileptic seizures are the result of synchronized neural activity that is excessive, and may stem from a failure of inhibitory neurons to regulate properly. It is a disorder with focal seizures in the occipital lobe of the brain. There are two main types of this epilepsy, each consisting of focal seizures- Gastaut and Panayiotopoulos (Pan.). Other names for the Gastaut type include benign epilepsy of childhood with occipital paroxysms (BECOP) and late-onset occipital epilepsy. Pan. is also known as self-limiting focal epilepsy of childhood with occipital paroxysms and early-onset benign partial epilepsy with occipital paroxysms. There may be no known cause of this type of seizure, but these epilepsies may occur for a variety of reasons, such as brain tumors, infection, trauma and lesions, and idiopathic onset. Seizures originate in the occipital lobe and account for 5 to 10 percent of all epileptic seizure types. Generally, this type of epilepsy can have an onset anywhere from 1–17 years old in children, but the patient prognosis is good. Since the event is located in the occipital lobe, symptoms may occur spontaneously and include visual stimuli.
  • 1.8K
  • 14 Nov 2022
Biography
Alan Lightman
Alan Paige Lightman is an American physicist, writer, and social entrepreneur. He has served on the faculties of Harvard and Massachusetts Institute of Technology (MIT) and is currently professor of the practice of the humanities at MIT. He is widely known as the author of the international bestseller Einstein's Dreams. Einstein's Dreams has been adapted into dozens of independent theatrical pro
  • 1.8K
  • 06 Dec 2022
Topic Review
Cytokine Release Syndrome
Cytokine release syndrome (CRS) is a form of systemic inflammatory response syndrome (SIRS) that can be triggered by a variety of factors such as infections and certain drugs. It refers to cytokine storm syndromes (CSS) and occurs when large numbers of white blood cells are activated and release inflammatory cytokines, which in turn activate yet more white blood cells. CRS is also an adverse effect of some monoclonal antibody medications, as well as adoptive T-cell therapies. When occurring as a result of a medication, it is also known as an infusion reaction. The term cytokine storm is often used interchangeably with CRS but, despite the fact that they have similar clinical phenotype, their characteristics are different. When occurring as a result of a therapy, CRS symptoms may be delayed until days or weeks after treatment. Immediate-onset CRS is a cytokine storm, although severe cases of CRS have also been called cytokine storms.
  • 1.8K
  • 29 Nov 2022
Topic Review
Diverticulosis
Diverticulosis is the condition of having multiple pouches (diverticula) in the colon that are not inflamed. These are outpockets of the colonic mucosa and submucosa through weaknesses of muscle layers in the colon wall, and may be due in part to low-fiber diet prompting changes in intestinal microflora with consequent low-grade inflammation. Diverticula do not cause symptoms in most people. Diverticular disease occurs when diverticula become clinically inflamed, a condition known as diverticulitis. Diverticula typically occur in the sigmoid colon, which is commonplace for increased pressure. The left side of the colon is more commonly affected in the United States while the right side is more commonly affected in Asia. Diagnosis is often during routine colonoscopy or as an incidental finding during CT scan. It is common in Western countries with about half of those over the age of 60 affected in Canada and the United States. Diverticula are uncommon before the age of 40, and increase in incidence beyond that age. Rates are lower in Africa; the reasons for this remain unclear but may involve the greater prevalence of a high fiber diet in contrast with the lower-fiber diet characteristic of many Western populations.
  • 1.8K
  • 10 Nov 2022
Topic Review
Sensory Memory
During every moment of an organism's life, sensory information is being taken in by sensory receptors and processed by the nervous system. Sensory information is stored in sensory memory just long enough to be transferred to short-term memory. Humans have five traditional senses: sight, hearing, taste, smell, touch. Sensory memory (SM) allows individuals to retain impressions of sensory information after the original stimulus has ceased. A common demonstration of SM is a child's ability to write letters and make circles by twirling a sparkler at night. When the sparkler is spun fast enough, it appears to leave a trail which forms a continuous image. This "light trail" is the image that is represented in the visual sensory store known as iconic memory. The other two types of SM that have been most extensively studied are echoic memory, and haptic memory; however, it is reasonable to assume that each physiological sense has a corresponding memory store. Children for example have been shown to remember specific "sweet" tastes during incidental learning trials but the nature of this gustatory store is still unclear. However, sensory memories might be related to a region of the thalamus, which serves as a source of signals encoding past experiences in the neocortex.
  • 1.8K
  • 30 Nov 2022
Topic Review
Nematophagous Fungi
Plant-parasitic nematodes significantly threaten agriculture and forestry, causing various diseases. They cause annual losses of up to 178 billion dollars worldwide due to their parasitism. Nematophagous fungi (NF) are valuable in controlling or reducing parasitic nematode diseases by killing nematodes through predatory behavior.
  • 1.8K
  • 09 Nov 2023
Topic Review
PhyloCode
The International Code of Phylogenetic Nomenclature, known as the PhyloCode for short, is a developing draft for a formal set of rules governing phylogenetic nomenclature. Its current version is specifically designed to regulate the naming of clades, leaving the governance of species names up to the rank-based Nomenclature codes (ICN, ICZN, ICNB, ICTV). The PhyloCode is associated with the International Society for Phylogenetic Nomenclature (ISPN). The PhyloCode proposes to regulate phylogenetic nomenclature by providing rules for how to decide which associations of names and definitions will be considered established, which of those will be considered homonyms or synonyms, and which one of a set of synonyms or homonyms will be considered accepted (generally the one registered first; see below). The PhyloCode will only allow the naming of clades, not of paraphyletic or polyphyletic groups, and will only allow the use of specimens, species, and apomorphies as specifiers (anchors).
  • 1.8K
  • 06 Oct 2022
Biography
Ivar Giaever
Ivar Giaever (Norwegian: Giæver, IPA: [ˈiːvɑr ˈjeːvər]; born April 5, 1929) is a Norwegian-American physicist who shared the Nobel Prize in Physics in 1973 with Leo Esaki and Brian Josephson "for their discoveries regarding tunnelling phenomena in solids".[1] Giaever's share of the prize was specifically for his "experimental discoveries regarding tunnelling phenomena in superconductors"
  • 1.8K
  • 15 Nov 2022
Biography
Philip M. Morse
Philip McCord Morse (August 6, 1903 – 5 September 1985), was an American physicist, administrator and pioneer of operations research (OR) in World War II.[1] He is considered to be the father of operations research in the U.S. Morse graduated from the Case School of Applied Science in 1926 with a B.S. in physics.[2] He earned his Ph.D. in physics from Princeton University in 1929.[3] In 19
  • 1.8K
  • 26 Dec 2022
Topic Review
Sleep Health Promotion Interventions
Sleep health promotion is the public health field that is concerned with improving sleep health in primarily healthy populations. Good sleep health is characterized by subjective satisfaction, appropriate timing, adequate duration, high efficiency, and sustained alertness during waking hours (Buysse,2014). As in the last decade evidence has been mounting that good sleep is crucial for health, sleep health promotion is receiving increasing attention in public health. In this contribution, an overview is provided of the sleep health promotion interventions that have been described in reviews. 
  • 1.8K
  • 31 May 2021
Topic Review
Free Recall
Free recall is a common task in the psychological study of memory. In this task, participants study a list of items on each trial, and then are prompted to recall the items in any order. Items are usually presented one at a time for a short duration, and can be any of a number of nameable materials, although traditionally, words from a larger set are chosen. The recall period typically lasts a few minutes, and can involve spoken or written recall. The standard test involves the recall period starting immediately after the final list item; this can be referred to as immediate free recall (IFR) to distinguish it from delayed free recall (DFR). In delayed free recall, there is a short distraction period between the final list item and the start of the recall period. Both IFR and DFR have been used to test certain effects that appear during recall tests, such as the primacy effect and recency effect.
  • 1.8K
  • 04 Nov 2022
Biography
Betty Williams (Nobel Laureate)
Betty Williams (born 22 May 1943, Belfast, Northern Ireland) is a co-recipient with Mairead Corrigan of the Nobel Peace Prize in 1976 for her work as a cofounder of Community of Peace People, an organization dedicated to promoting a peaceful resolution to the Troubles in Northern Ireland. Williams heads the Global Children's Foundation and is the President of the World Centre of Compassion for
  • 1.8K
  • 21 Nov 2022
Topic Review
Edentulism
Edentulism or toothlessness is the condition of being toothless to at least some degree; in organisms (such as humans) that naturally have teeth (dentition), it is the result of tooth loss. Loss of some teeth is called partial edentulism, whereas loss of all teeth is called complete edentulism. Persons who have lost teeth are (either partially or completely) edentulous (edentate), whereas those who have not lost teeth can be called dentate by comparison. For example, a scientific study may include a partially edentulous group and a healthy dentate control group. Organisms that never possessed teeth can also be described as edentulous, such as members of the former zoological classification order of Edentata, which included anteaters and sloths, all of which possess no anterior teeth and either no or poorly developed posterior teeth. In naturally dentate species, edentulism is more than just the simple presence or absence of teeth; it is biochemically complex, because the teeth, jaws, and oral mucosa are not static objects; they are dynamic (changing over time). Processes such as bone remodeling (loss and gain of bone tissue) in the jaws and inflammation of soft tissue in response to the oral microbiota are clinically important for edentulous people. For example, bone resorption in the jaw is frequently how the teeth were able to detach in the first place; the jaw in an edentulous area undergoes further resorption even after the teeth are gone; and insertion of dental implants can elicit new bone formation, leading to osseointegration. Meanwhile, bacteria and yeasts of the oral cavity and the immune system of their host create an immensely complicated and constantly changing interplay that presents clinically as gingivitis, caries, stomatitis, and other periodontal pathology.
  • 1.8K
  • 18 Oct 2022
Topic Review
Short-Beaked Echidna
The short-beaked echidna (Tachyglossus aculeatus) is one of four living species of echidna and the only member of the genus Tachyglossus. It is covered in fur and spines and has a distinctive snout and a specialized tongue, which it uses to catch its insect prey at a great speed. Like the other extant monotremes, the short-beaked echidna lays eggs; the monotremes are the only living group of mammals to do so. The short-beaked echidna has extremely strong front limbs and claws, which allow it to burrow quickly with great power. As it needs to be able to survive underground, it has a significant tolerance to high levels of carbon dioxide and low levels of oxygen. It has no weapons or fighting ability but repels predators by curling into a ball and deterring them with its spines. It lacks the ability to sweat and cannot deal with heat well, so it tends to avoid daytime activity in hot weather. It can swim if needed. The snout has mechanoreceptors and electroreceptors that help the echidna to detect its surroundings. During the Australia n winter, it goes into deep torpor and hibernation, reducing its metabolism to save energy. As the temperature increases, it emerges to mate. Female echidnas lay one egg a year and the mating period is the only time the otherwise solitary animals meet one another; the male has no further contact with the female or his offspring after mating. A newborn echidna is the size of a grape but grows rapidly on its mother's milk, which is very rich in nutrients. Baby echidnas eventually grow too large and spiky to stay in the pouch and, around seven weeks after hatching, are expelled from the pouch into the mother's burrow. At around six months of age, they leave the burrow and have no more contact with their mothers. The species is found throughout Australia, where it is the most widespread native mammal, and in coastal and highland regions of eastern New Guinea, where it is known as the mungwe in the Daribi and Chimbu languages. It is not threatened with extinction, but human activities, such as hunting, habitat destruction, and the introduction of foreign predatory species and parasites, have reduced its distribution in Australia.
  • 1.8K
  • 29 Nov 2022
  • Page
  • of
  • 68
Featured Entry Collections
>>

Featured Reprints

>>
Encyclopedia of Digital Society, Industry 5.0 and Smart City
Encyclopedia of Engineering
Encyclopedia of Social Sciences
Encyclopedia of Medieval Royal Iconography
Academic Video Service
Feedback