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Topic Review
Species Problem
The species problem is the set of questions that arises when biologists attempt to define what a species is. Such a definition is called a species concept; there are at least 26 recognized species concepts. A species concept that works well for sexually reproducing organisms such as birds is useless for species that reproduce asexually, such as bacteria. The scientific study of the species problem has been called microtaxonomy. One common, but sometimes difficult, question is how best to decide which species an organism belongs to, because reproductively isolated groups may not be readily recognizable, and cryptic species may be present. There is a continuum from reproductive isolation with no interbreeding, to panmixis, unlimited interbreeding. Populations can move forward or backwards along this continuum, at any point meeting the criteria for one or another species concept, and failing others. Many of the debates on species touch on philosophical issues, such as nominalism and realism, and on issues of language and cognition. The current meaning of the phrase "species problem" is quite different from what Charles Darwin and others meant by it during the 19th and early 20th centuries. For Darwin, the species problem was the question of how new species arose. Darwin was however one of the first people to question how well-defined species are, given that they constantly change.
  • 5.1K
  • 02 Nov 2022
Biography
Hutton Gibson
Hutton Peter Gibson (born August 26, 1918) is an American writer on Sedevacantism, a World War II veteran, the 1968 Jeopardy! grand champion and the father of 11 children, one of whom is the actor and director Mel Gibson. Gibson is an outspoken critic, both of the post-Vatican II Roman Catholic Church and of those Traditionalist Catholics, like the Society of Saint Pius X, who reject Sedevacant
  • 5.0K
  • 27 Dec 2022
Biography
Hans Adolf Krebs
Sir Hans Adolf Krebs (/krɛbz, krɛps/; 25 August 1900 – 22 November 1981)[1][2][3][4] was a German-born British biologist, physician and biochemist.[5] He was a pioneer scientist in the study of cellular respiration, a biochemical process in living cells that extracts energy from food and oxygen and makes it available to drive the processes of life.[6][7] He is best known for his discoveries
  • 5.0K
  • 29 Nov 2022
Topic Review
Dilophosauridae
Dilophosauridae is a family of medium to large sized theropod dinosaurs. The name Dilophosauridae is derived from Greek, with “di-” meaning “two,” “lophos” meaning “crest,” “sauros” meaning “lizard,” and “-idae” meaning “family”. While the name suggests that all dilophosaurids have two crests, this is not applicable to all dilophosaurids. The Dilophosauridae is anchored by its type genus, Dilophosaurus, and therefore the name comes from the distinctive two crests of the genus.
  • 4.9K
  • 24 Oct 2022
Biography
Hans Geiger
Johannes Wilhelm "Hans" Geiger (30 September 1882 – 24 September 1945) was a German physicist. He is best known as the co-inventor of the detector component of the Geiger counter and for the Geiger–Marsden experiment which discovered the atomic nucleus. Geiger was born at Neustadt an der Haardt, Germany. He was one of five children born to the Indologist Wilhelm Ludwig Geiger, who was a pr
  • 4.9K
  • 25 Nov 2022
Topic Review
Nanotyrannus
Nanotyrannus ("dwarf tyrant") is a likely invalid genus of tyrannosaurid dinosaur. It is known from only a single certain specimen, CMNH 7541, that was originally proposed to be a distinct genus based on a handful of cranial and postcranial features. It has since been suggested to be juvenile of the contemporary species Tyrannosaurus rex, based on a lack of mature specimens and the proposed diagnostic traits being variable within the species, a conclusion that is not universally accepted.
  • 4.9K
  • 07 Nov 2022
Topic Review
Effects of Global Warming
The effects of global warming or climate damage include far-reaching and long-lasting changes to the natural environment, to ecosystems and human societies caused directly or indirectly by human emissions of greenhouse gases. It also includes the economic and social changes which stem from living in a warmer world. Human caused climate change is one of the threats to sustainability. Many physical impacts of global warming are already visible, including extreme weather events, glacier retreat, changes in the timing of seasonal events (e.g., earlier flowering of plants), sea level rise, and declines in Arctic sea ice extent. The future impact of global warming depends on the extent to which nations implement prevention efforts and reduce greenhouse gas emissions. Ocean acidification is not a consequence of global warming, but instead has the same cause: increasing atmospheric carbon dioxide. Climate change has already impacted ecosystems and humans as well. In combination with climate variability, it makes food insecurity worse in many places and puts pressure on fresh water supply. This in combination with extreme weather events, leads to negative effects on human health. Rising temperatures threaten development because of negative effects on economic growth in developing countries. The social impact of climate change will be further affected by society's efforts to prepare and adapt. Global warming already contributes to migration in different parts of the world. Near-term climate change policies significantly affect long-term climate change impacts. Stringent mitigation policies might be able to limit global warming (in 2100) to around 2 °C or below, relative to pre-industrial levels. Without mitigation, increased energy demand and extensive use of fossil fuels might lead to global warming of around 4 °C. Higher magnitudes of global warming would be more difficult to adapt to, and would increase the risk of negative impacts.
  • 4.8K
  • 01 Nov 2022
Topic Review
History of Neurology and Neurosurgery
The study of neurology and neurosurgery dates back to prehistoric times, but the academic disciplines did not begin until the 16th century. From an observational science they developed a systematic way of approaching the nervous system and possible interventions in neurological disease.
  • 4.8K
  • 14 Oct 2022
Topic Review
Triticum Dicoccum
Emmer wheat or hulled wheat is a type of awned wheat. Emmer is a tetraploid (2n = 4x = 28 chromosomes). The domesticated types are Triticum turgidum subsp. dicoccum and Triticum turgidum conv. durum. The wild plant is called Triticum turgidum subsp. dicoccoides. The principal difference between the wild and the domestic is that the ripened seed head of the wild plant shatters and scatters the seed onto the ground, while in the domesticated emmer the seed head remains intact, thus making it easier for humans to harvest the grain. Along with einkorn wheat, emmer was one of the first crops domesticated in the Near East. It was widely cultivated in the ancient world, but is now a relict crop in mountainous regions of Europe and Asia. Emmer is considered a type of farro food especially in Italy.
  • 4.7K
  • 07 Nov 2022
Biography
Sri Bhagavan
Sri Bhagavan (also known as 'Kalki' Bhagwan, born 7 March 1949)[1][2] is a spiritual teacher from India, and founder of Oneness University, a spiritual school located in South India.[3][4] In October 2019, newspapers reported that the Income Tax Department had raided 40 different properties associated with "White Lotus", owned by his son, and had confiscated large amounts of cash and gold.[5][6]
  • 4.7K
  • 09 Dec 2022
Topic Review
Sinhapura
Sinhapura (Sanskrit, "Lion City"; IAST: Siṃhapura) was the capital of the legendary Indian king Sinhabahu. It has been mentioned in the Buddhist legends about Prince Vijaya. The name is also transliterated as Sihapura or Singhapura. The location of Sinhapura is disputed with some scholars claiming the city was located in eastern India and others claiming it was located in present-day Malaysia or Thailand. The city is linked to the origin of the Sinhalese people and Sinhalese Buddhist mythology.
  • 4.7K
  • 27 Oct 2022
Biography
William Luther Pierce
William Luther Pierce III (September 11, 1933 – July 23, 2002) was an American white supremacist, author, and political activist.[1][2] He was one of the most influential ideologues of the white nationalist movement for some 30 years before his death. A physicist by profession, he was also an author under the pseudonym Andrew Macdonald of the novels The Turner Diaries and Hunter. Pierce founde
  • 4.7K
  • 25 Nov 2022
Topic Review
Recognition Memory
Recognition memory, a subcategory of declarative memory, is the ability to recognize previously encountered events, objects, or people. When the previously experienced event is reexperienced, this environmental content is matched to stored memory representations, eliciting matching signals. As first established by psychology experiments in the 1970s, recognition memory for pictures is quite remarkable: humans can remember thousands of images at high accuracy after seeing each only once and only for a few seconds. Recognition memory can be subdivided into two component processes: recollection and familiarity, sometimes referred to as "remembering" and "knowing", respectively. Recollection is the retrieval of details associated with the previously experienced event. In contrast, familiarity is the feeling that the event was previously experienced, without recollection. Thus, the fundamental distinction between the two processes is that recollection is a slow, controlled search process, whereas familiarity is a fast, automatic process. Mandler's "Butcher-on-the-bus" example: Imagine taking a seat on a crowded bus. You look to your left and notice a man. Immediately, you are overcome with this sense that you've seen this man before, but you cannot remember who he is. This automatically elicited feeling is familiarity. While trying to remember who this man is, you begin retrieving specific details about your previous encounter. For example, you might remember that this man handed you a fine chop of meat in the grocery store. Or perhaps you remember him wearing an apron. This search process is recollection.
  • 4.7K
  • 29 Nov 2022
Biography
Pandurang Shastri Athavale
Pandurang Shastri Athavale (19 October 1920 – 25 October 2003), also known as Dadaji, which literally translates as "elder brother" in Marathi, was an Indian activist, philosopher, spiritual leader, social revolutionary,[1] and religion reformist, who founded the Swadhyaya Parivar (Swadhyaya Family) in 1954.[2] Swadhyaya is a self-study process based on the Bhagavad Gita which has spread acros
  • 4.7K
  • 02 Dec 2022
Biography
Mustafa Tlass
Mustafa Abdul Qadir Tlass (Arabic: مصطفى طلاس; 11 May 1932 – 27 June 2017) was a Syrian senior military officer and politician who was Syria's minister of defense from 1972 to 2004.[1] He was part of the four-member Regional Command during the Hafez Assad era. Tlass was born in Rastan near the city of Homs to a prominent local Sunni Muslim family on 11 May 1932.[2] His father, Abdu
  • 4.6K
  • 05 Dec 2022
Topic Review
Start School Later Movement
The movement to start school later consists of efforts by health care professionals, sleep scientists, educators, economists, legislators, parents, students, and other concerned citizens to restore a later start to the school day. Based on a growing body of evidence that starting middle and high schools too early in the morning is unhealthy, counterproductive, and incompatible with adolescent sleep needs and patterns. During the second half of the 20th century, many public schools in the United States began shifting instructional time earlier than the more conventional bell time, thought to be about 9 a.m. Today it is common for American schools to begin the instructional day in the 7 a.m. hour and end about seven hours later, around 2 p.m. Most sleep research suggests that morning classes should begin no earlier than 8:30 a.m. for middle and high school students. Advocates of a return to later school start times argue that sleep and school hours should be viewed as a public health issue, citing evidence linking early school start times to widespread sleep deprivation among teenagers as well as a wide array of acute and chronic physical, psychological, and educational problems. Not only do students consistently get significantly more sleep on school nights when their schools move to later start times, but later school hours have been consistently linked with improved school performance, reduced impulsiveness, and greater motivation, as well as with lower rates of depression, tardiness, truancy, and morning automobile accidents. Recent (2011) studies suggest that early school start times disproportionately hurt economically disadvantaged students and may even negatively impact future earning potential of students, offsetting any financial savings to the school system attributed to earlier hours.
  • 4.6K
  • 06 Oct 2022
Topic Review
Competition
Competition is an interaction between organisms or species in which both require a resource that is in limited supply (such as food, water, or territory). Competition lowers the fitness of both organisms involved, since the presence of one of the organisms always reduces the amount of the resource available to the other. In the study of community ecology, competition within and between members of a species is an important biological interaction. Competition is one of many interacting biotic and abiotic factors that affect community structure, species diversity, and population dynamics (shifts in a population over time). There are three major mechanisms of competition: interference, exploitation, and apparent competition (in order from most direct to least direct). Interference and exploitation competition can be classed as "real" forms of competition, while apparent competition is not, as organisms do not share a resource, but instead share a predator. Competition among members of the same species is known as intraspecific competition, while competition between individuals of different species is known as interspecific competition. According to the competitive exclusion principle, species less suited to compete for resources must either adapt or die out, although competitive exclusion is rarely found in natural ecosystems. According to evolutionary theory, competition within and between species for resources is important in natural selection. More recently, however, researchers have suggested that evolutionary biodiversity for vertebrates has been driven not by competition between organisms, but by these animals adapting to colonize empty livable space; this is termed the 'Room to Roam' hypothesis.
  • 4.6K
  • 28 Nov 2022
Biography
Jeff Dean
Jeffrey Adgate "Jeff" Dean (born July 1968) is an American computer scientist and software engineer. He is currently the lead of Google AI, Google's AI division.[1] Dean received a B.S., summa cum laude from the University of Minnesota in Computer Science & Engineering in 1990.[2] He received a Ph.D. in Computer Science from the University of Washington, working under Craig Chambers on compil
  • 4.6K
  • 29 Dec 2022
Topic Review
Cincinnati Radiation Experiments (1960-1971)
The Cincinnati Radiation Experiments were a series of total and partial body irradiation tests performed on at least 90 patients with advanced cancer at the Cincinnati General Hospital, now University Hospital, from 1960-1971. Led by radiologist Dr. Eugene L. Saenger, the experiments were funded in part by the Defense Atomic Support Agency within the Department of Defense to study how soldiers in nuclear war would be affected by large doses of radiation. The experiments were conducted without patient consent in the first five years of the study and with disputed levels of consent thereafter. The irradiated patients experienced nausea, vomiting, cognitive impairment, and death. The contract between the researchers and the DOD terminated in 1972 under pressure from Senator Edward Kennedy, marking the end of major human irradiation experimentation in the U.S. that began after World War II and continued throughout the Cold War Era. Although initially fading from public eye, the controversy resurfaced in 1993 and was soon investigated by President Bill Clinton’s Advisory Committee on Human Radiation Experiments. In 1994, families of the patients filed a class-action lawsuit against the team of 15 researchers. Five years later, the University of Cincinnati settled the case for over $4 million.
  • 4.6K
  • 20 Oct 2022
Topic Review
Pluteus Larva
An echinoderm (/ɪˈkaɪnəˌdɜːrm, ˈɛkə-/) is any member of the phylum Echinodermata (/ɪˌkaɪnoʊˈdɜːrmətə/). The adults are recognisable by their (usually five-point) radial symmetry, and include starfish, brittle stars, sea urchins, sand dollars, and sea cucumbers, as well as the sea lilies or "stone lilies". Adult echinoderms are found on the sea bed at every ocean depth, from the intertidal zone to the abyssal zone. The phylum contains about 7,000 living species, making it the second-largest grouping of deuterostomes, after the chordates. Echinoderms are the largest entirely marine phylum. The first definitive echinoderms appeared near the start of the Cambrian. The echinoderms are important both ecologically and geologically. Ecologically, there are few other groupings so abundant in the biotic desert of the deep sea, as well as shallower oceans. Most echinoderms are able to reproduce asexually and regenerate tissue, organs, and limbs; in some cases, they can undergo complete regeneration from a single limb. Geologically, the value of echinoderms is in their ossified skeletons, which are major contributors to many limestone formations, and can provide valuable clues as to the geological environment. They were the most used species in regenerative research in the 19th and 20th centuries. Further, some scientists hold that the radiation of echinoderms was responsible for the Mesozoic Marine Revolution.
  • 4.6K
  • 28 Nov 2022
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