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Hyperactive apoptosis
On the other hand, loss of control of cell death (resulting in excess apoptosis) can lead to neurodegenerative diseases, hematologic diseases, and tissue damage. Neurons that rely on mitochondrial respiration undergo apoptosis in neurodegenerative diseases such as Alzheimer's and Parkinson's. (an ... | Apoptosis | Wikipedia | 478 | 2457 | https://en.wikipedia.org/wiki/Apoptosis | Biology and health sciences | Cell processes | Biology |
HIV progression
The progression of the human immunodeficiency virus infection into AIDS is due primarily to the depletion of CD4+ T-helper lymphocytes in a manner that is too rapid for the body's bone marrow to replenish the cells, leading to a compromised immune system. One of the mechanisms by which T-helper cells ar... | Apoptosis | Wikipedia | 368 | 2457 | https://en.wikipedia.org/wiki/Apoptosis | Biology and health sciences | Cell processes | Biology |
Researchers from Kumamoto University in Japan have developed a new method to eradicate HIV in viral reservoir cells, named "Lock-in and apoptosis." Using the synthesized compound Heptanoylphosphatidyl L-Inositol Pentakisphophate (or L-Hippo) to bind strongly to the HIV protein PR55Gag, they were able to suppress viral ... | Apoptosis | Wikipedia | 240 | 2457 | https://en.wikipedia.org/wiki/Apoptosis | Biology and health sciences | Cell processes | Biology |
Viruses can trigger apoptosis of infected cells via a range of mechanisms including:
Receptor binding
Activation of protein kinase R (PKR)
Interaction with p53
Expression of viral proteins coupled to MHC proteins on the surface of the infected cell, allowing recognition by cells of the immune system (such as natura... | Apoptosis | Wikipedia | 470 | 2457 | https://en.wikipedia.org/wiki/Apoptosis | Biology and health sciences | Cell processes | Biology |
With the use of gel electrophoresis, it can be observed that OROV causes DNA fragmentation in HeLa cells. It can be interpreted by counting, measuring, and analyzing the cells of the Sub/G1 cell population. When HeLA cells are infected with OROV, the cytochrome C is released from the membrane of the mitochondria, into ... | Apoptosis | Wikipedia | 491 | 2457 | https://en.wikipedia.org/wiki/Apoptosis | Biology and health sciences | Cell processes | Biology |
Plants
Programmed cell death in plants has a number of molecular similarities to that of animal apoptosis, but it also has differences, notable ones being the presence of a cell wall and the lack of an immune system that removes the pieces of the dead cell. Instead of an immune response, the dying cell synthesizes sub... | Apoptosis | Wikipedia | 297 | 2457 | https://en.wikipedia.org/wiki/Apoptosis | Biology and health sciences | Cell processes | Biology |
The aurochs (Bos primigenius) ( or , plural aurochs or aurochsen) is an extinct species of bovine, considered to be the wild ancestor of modern domestic cattle. With a shoulder height of up to in bulls and in cows, it was one of the largest herbivores in the Holocene; it had massive elongated and broad horns that rea... | Aurochs | Wikipedia | 500 | 2494 | https://en.wikipedia.org/wiki/Aurochs | Biology and health sciences | Artiodactyla | null |
The use of the plural form in English is a direct parallel of the German plural Ochsen and recreates the same distinction by analogy as English singular ox and plural oxen, although aurochs may stand for both the singular and the plural term; both are attested.
Taxonomy and evolution
The scientific name Bos taurus w... | Aurochs | Wikipedia | 454 | 2494 | https://en.wikipedia.org/wiki/Aurochs | Biology and health sciences | Artiodactyla | null |
Evolution
Calibrations using fossils of 16 Bovidae species indicate that the Bovini tribe evolved about . The Bos and Bison genetic lineages are estimated to have genetically diverged from the Bovini about . The following cladogram shows the phylogenetic relationships of the aurochs based on analysis of nuclear and mi... | Aurochs | Wikipedia | 508 | 2494 | https://en.wikipedia.org/wiki/Aurochs | Biology and health sciences | Artiodactyla | null |
According to a 16th-century description by Sigismund von Herberstein, the aurochs was pitch-black with a grey streak along the back; his wood carving made in 1556 was based on a culled aurochs, which he had received in Mazovia. In 1827, Charles Hamilton Smith published an image of an aurochs that was based on an oil pa... | Aurochs | Wikipedia | 406 | 2494 | https://en.wikipedia.org/wiki/Aurochs | Biology and health sciences | Artiodactyla | null |
The proportions and body shape of the aurochs were strikingly different from many modern cattle breeds. For example, the legs were considerably longer and more slender, resulting in a shoulder height that nearly equalled the trunk length. The skull, carrying the large horns, was substantially larger and more elongated ... | Aurochs | Wikipedia | 447 | 2494 | https://en.wikipedia.org/wiki/Aurochs | Biology and health sciences | Artiodactyla | null |
Genetics
A well-preserved aurochs bone yielded sufficient mitochondrial DNA for a sequence analysis in 2010, which showed that its genome consists of 16,338 base pairs. Further studies using the aurochs whole genome sequence have identified candidate microRNA-regulated domestication genes. A comprehensive sequence anal... | Aurochs | Wikipedia | 499 | 2494 | https://en.wikipedia.org/wiki/Aurochs | Biology and health sciences | Artiodactyla | null |
Landscapes in Europe probably consisted of dense forests throughout much of the last few thousand years. The aurochs is likely to have used riparian forests and wetlands along lakes. Analysis of specimens found in Britain suggests that aurochs preferred inhabiting low lying relatively flat landscapes. Pollen of mostly ... | Aurochs | Wikipedia | 319 | 2494 | https://en.wikipedia.org/wiki/Aurochs | Biology and health sciences | Artiodactyla | null |
Mating season was in September, and calves were born in spring. Rutting bulls had violent fights, and evidence from the Jaktorów forest shows that they were fully capable of mortally wounding one another. In autumn, aurochs fed for the winter, gaining weight and possessing a shinier coat than during the rest of the yea... | Aurochs | Wikipedia | 400 | 2494 | https://en.wikipedia.org/wiki/Aurochs | Biology and health sciences | Artiodactyla | null |
Acheulean layers in Hunasagi on India's southern Deccan Plateau yielded aurochs bones with cut marks. An aurochs bone with cut marks induced with flint was found in a Middle Paleolithic layer at the Nesher Ramla Homo site in Israel; it was dated to Marine Isotope Stage 5 about 120,000 years ago. An archaeological excav... | Aurochs | Wikipedia | 435 | 2494 | https://en.wikipedia.org/wiki/Aurochs | Biology and health sciences | Artiodactyla | null |
In Africa
Petroglyphs depicting aurochs found in Qurta in the upper Nile valley were dated to the Late Pleistocene about 19–15,000 years BP using luminescence dating and are the oldest engravings found to date in Africa. Aurochs are part of hunting scenes in reliefs in a tomb at Thebes, Egypt dating to the 20th centur... | Aurochs | Wikipedia | 231 | 2494 | https://en.wikipedia.org/wiki/Aurochs | Biology and health sciences | Artiodactyla | null |
The aurochs is widely represented in Upper Paleolithic cave paintings in the Chauvet and Lascaux caves in southern France dating to 36,000 and 21,000 years BP, respectively.
Two Paleolithic rock engravings in the Calabrian Romito Cave depict an aurochs.
Palaeolithic engravings showing aurochs were also found in the Gro... | Aurochs | Wikipedia | 413 | 2494 | https://en.wikipedia.org/wiki/Aurochs | Biology and health sciences | Artiodactyla | null |
In the , Sigurd kills four aurochs. During the Middle Ages, aurochs horns were used as drinking horns including the horn of the last bull; many aurochs horn sheaths are preserved today. The aurochs drinking horn at Corpus Christi College, Cambridge was engraved with the college's coat of arms in the 17th century.
An au... | Aurochs | Wikipedia | 231 | 2494 | https://en.wikipedia.org/wiki/Aurochs | Biology and health sciences | Artiodactyla | null |
Domestication
The earliest-known domestication of the aurochs dates to the Neolithic Revolution in the Fertile Crescent, where cattle hunted and kept by Neolithic farmers gradually decreased in size between 9800 and 7500 BC. Aurochs bones found at Mureybet and Göbekli Tepe are larger in size than cattle bones from lat... | Aurochs | Wikipedia | 447 | 2494 | https://en.wikipedia.org/wiki/Aurochs | Biology and health sciences | Artiodactyla | null |
Comparative analysis of single-nucleotide polymorphisms and shared alleles revealed admixture between East Asian aurochs and introduced taurine cattle in ancient China, for example at Shimao. This suggested the incorporation of local aurochs into domestic cattle as far back as 4,000 years BP, either through spontaneous... | Aurochs | Wikipedia | 470 | 2494 | https://en.wikipedia.org/wiki/Aurochs | Biology and health sciences | Artiodactyla | null |
The Indian aurochs (B. p. namadicus) became extinct sometime during the Holocene period, likely due to habitat loss caused by expanding pastoralism and interbreeding with the domestic zebu. The timing of extinction of aurochs in the Indian subcontinent is unclear, due to difficulty distinguishing aurochs remains from t... | Aurochs | Wikipedia | 479 | 2494 | https://en.wikipedia.org/wiki/Aurochs | Biology and health sciences | Artiodactyla | null |
The last-known aurochs herd lived in a marshy woodland in Poland's Jaktorów Forest. It decreased from around 50 individuals in the mid 16th century to four individuals by 1601. The last aurochs cow died in 1627 from natural causes.
A 2021 study argued that the aurochs possibly survived in northeastern Bulgaria until a... | Aurochs | Wikipedia | 356 | 2494 | https://en.wikipedia.org/wiki/Aurochs | Biology and health sciences | Artiodactyla | null |
In mammals, invertebrates and most fish, the anus (: anuses or ani; from Latin, 'ring' or 'circle') is the external body orifice at the exit end of the digestive tract (bowel), i.e. the opposite end from the mouth. Its function is to facilitate the expulsion of wastes that remain after digestion.
Bowel contents that p... | Anus | Wikipedia | 488 | 2500 | https://en.wikipedia.org/wiki/Anus | Biology and health sciences | Gastrointestinal tract | Biology |
In comb jellies, there are species with one and sometimes two permanent anuses, species like the warty comb jelly grows an anus, which then disappear when it is no longer needed.
Development
In animals at least as complex as an earthworm, the embryo forms a dent on one side, the blastopore, which deepens to become th... | Anus | Wikipedia | 198 | 2500 | https://en.wikipedia.org/wiki/Anus | Biology and health sciences | Gastrointestinal tract | Biology |
Amphetamine (contracted from alpha-methylphenethylamine) is a central nervous system (CNS) stimulant that is used in the treatment of attention deficit hyperactivity disorder (ADHD), narcolepsy, and obesity; it is also used to treat binge eating disorder in the form of its inactive prodrug lisdexamfetamine. Amphetamine... | Amphetamine | Wikipedia | 370 | 2504 | https://en.wikipedia.org/wiki/Amphetamine | Biology and health sciences | Drugs and pharmacology | null |
At therapeutic doses, amphetamine causes emotional and cognitive effects such as euphoria, change in desire for sex, increased wakefulness, and improved cognitive control. It induces physical effects such as improved reaction time, fatigue resistance, decreased appetite, elevated heart rate, and increased muscle streng... | Amphetamine | Wikipedia | 487 | 2504 | https://en.wikipedia.org/wiki/Amphetamine | Biology and health sciences | Drugs and pharmacology | null |
Reviews of clinical stimulant research have established the safety and effectiveness of long-term continuous amphetamine use for the treatment of ADHD. Randomized controlled trials of continuous stimulant therapy for the treatment of ADHD spanning 2 years have demonstrated treatment effectiveness and safety. Two review... | Amphetamine | Wikipedia | 360 | 2504 | https://en.wikipedia.org/wiki/Amphetamine | Biology and health sciences | Drugs and pharmacology | null |
Models of ADHD suggest that it is associated with functional impairments in some of the brain's neurotransmitter systems; these functional impairments involve impaired dopamine neurotransmission in the mesocorticolimbic projection and norepinephrine neurotransmission in the noradrenergic projections from the locus coer... | Amphetamine | Wikipedia | 480 | 2504 | https://en.wikipedia.org/wiki/Amphetamine | Biology and health sciences | Drugs and pharmacology | null |
Lisdexamfetamine's therapeutic effects for BED primarily involve direct action in the central nervous system after conversion to its pharmacologically active metabolite, dextroamphetamine. Centrally, dextroamphetamine increases neurotransmitter activity of dopamine and norepinephrine in prefrontal cortical regions that... | Amphetamine | Wikipedia | 269 | 2504 | https://en.wikipedia.org/wiki/Amphetamine | Biology and health sciences | Drugs and pharmacology | null |
Medical reviews of randomized controlled trials have demonstrated that lisdexamfetamine, at doses between 50–70 mg, is safe and effective for the treatment of moderate-to-severe BED in adults. These reviews suggest that lisdexamfetamine is persistently effective at treating BED and is associated with significant reduct... | Amphetamine | Wikipedia | 490 | 2504 | https://en.wikipedia.org/wiki/Amphetamine | Biology and health sciences | Drugs and pharmacology | null |
Amphetamine’s therapeutic mode of action in narcolepsy primarily involves increasing monoamine neurotransmitter activity in the ARAS. This includes noradrenergic neurons in the locus coeruleus, dopaminergic neurons in the ventral tegmental area, histaminergic neurons in the tuberomammillary nucleus, and serotonergic ne... | Amphetamine | Wikipedia | 451 | 2504 | https://en.wikipedia.org/wiki/Amphetamine | Biology and health sciences | Drugs and pharmacology | null |
Cognitive performance
In 2015, a systematic review and a meta-analysis of high quality clinical trials found that, when used at low (therapeutic) doses, amphetamine produces modest yet unambiguous improvements in cognition, including working memory, long-term episodic memory, inhibitory control, and some aspects of att... | Amphetamine | Wikipedia | 308 | 2504 | https://en.wikipedia.org/wiki/Amphetamine | Biology and health sciences | Drugs and pharmacology | null |
Amphetamine is used by some athletes for its psychological and athletic performance-enhancing effects, such as increased endurance and alertness; however, non-medical amphetamine use is prohibited at sporting events that are regulated by collegiate, national, and international anti-doping agencies. In healthy people at... | Amphetamine | Wikipedia | 231 | 2504 | https://en.wikipedia.org/wiki/Amphetamine | Biology and health sciences | Drugs and pharmacology | null |
Recreational
Amphetamine, specifically the more dopaminergic dextrorotatory enantiomer (dextroamphetamine), is also used recreationally as a euphoriant and aphrodisiac, and like other amphetamines; is used as a club drug for its energetic and euphoric high. Dextroamphetamine (d-amphetamine) is considered to have a high... | Amphetamine | Wikipedia | 497 | 2504 | https://en.wikipedia.org/wiki/Amphetamine | Biology and health sciences | Drugs and pharmacology | null |
According to the International Programme on Chemical Safety (IPCS) and the U.S. Food and Drug Administration (FDA), amphetamine is contraindicated in people with a history of drug abuse, cardiovascular disease, severe agitation, or severe anxiety. It is also contraindicated in individuals with advanced arteriosclerosis... | Amphetamine | Wikipedia | 438 | 2504 | https://en.wikipedia.org/wiki/Amphetamine | Biology and health sciences | Drugs and pharmacology | null |
Physical
Cardiovascular side effects can include hypertension or hypotension from a vasovagal response, Raynaud's phenomenon (reduced blood flow to the hands and feet), and tachycardia (increased heart rate). Sexual side effects in males may include erectile dysfunction, frequent erections, or prolonged erections. Gast... | Amphetamine | Wikipedia | 419 | 2504 | https://en.wikipedia.org/wiki/Amphetamine | Biology and health sciences | Drugs and pharmacology | null |
Psychological
At normal therapeutic doses, the most common psychological side effects of amphetamine include increased alertness, apprehension, concentration, initiative, self-confidence and sociability, mood swings (elated mood followed by mildly depressed mood), insomnia or wakefulness, and decreased sense of fatigue... | Amphetamine | Wikipedia | 467 | 2504 | https://en.wikipedia.org/wiki/Amphetamine | Biology and health sciences | Drugs and pharmacology | null |
Biomolecular mechanisms
Chronic use of amphetamine at excessive doses causes alterations in gene expression in the mesocorticolimbic projection, which arise through transcriptional and epigenetic mechanisms. The most important transcription factors that produce these alterations are Delta FBJ murine osteosarcoma viral ... | Amphetamine | Wikipedia | 281 | 2504 | https://en.wikipedia.org/wiki/Amphetamine | Biology and health sciences | Drugs and pharmacology | null |
ΔJunD, a transcription factor, and G9a, a histone methyltransferase enzyme, both oppose the function of ΔFosB and inhibit increases in its expression. Sufficiently overexpressing ΔJunD in the nucleus accumbens with viral vectors can completely block many of the neural and behavioral alterations seen in chronic drug abu... | Amphetamine | Wikipedia | 436 | 2504 | https://en.wikipedia.org/wiki/Amphetamine | Biology and health sciences | Drugs and pharmacology | null |
there is no effective pharmacotherapy for amphetamine addiction. Reviews from 2015 and 2016 indicated that TAAR1-selective agonists have significant therapeutic potential as a treatment for psychostimulant addictions; however, the only compounds which are known to function as TAAR1-selective agonists are experimental ... | Amphetamine | Wikipedia | 378 | 2504 | https://en.wikipedia.org/wiki/Amphetamine | Biology and health sciences | Drugs and pharmacology | null |
Behavioral treatments
A 2018 systematic review and network meta-analysis of 50 trials involving 12 different psychosocial interventions for amphetamine, methamphetamine, or cocaine addiction found that combination therapy with both contingency management and community reinforcement approach had the highest efficacy (i.... | Amphetamine | Wikipedia | 340 | 2504 | https://en.wikipedia.org/wiki/Amphetamine | Biology and health sciences | Drugs and pharmacology | null |
Dependence and withdrawal
Drug tolerance develops rapidly in amphetamine abuse (i.e., recreational amphetamine use), so periods of extended abuse require increasingly larger doses of the drug in order to achieve the same effect.
According to a Cochrane review on withdrawal in individuals who compulsively use amphetamin... | Amphetamine | Wikipedia | 381 | 2504 | https://en.wikipedia.org/wiki/Amphetamine | Biology and health sciences | Drugs and pharmacology | null |
Toxicity
In rodents and primates, sufficiently high doses of amphetamine cause dopaminergic neurotoxicity, or damage to dopamine neurons, which is characterized by dopamine terminal degeneration and reduced transporter and receptor function. There is no evidence that amphetamine is directly neurotoxic in humans. Howeve... | Amphetamine | Wikipedia | 334 | 2504 | https://en.wikipedia.org/wiki/Amphetamine | Biology and health sciences | Drugs and pharmacology | null |
Many types of substances are known to interact with amphetamine, resulting in altered drug action or metabolism of amphetamine, the interacting substance, or both. Inhibitors of enzymes that metabolize amphetamine (e.g., CYP2D6 and FMO3) will prolong its elimination half-life, meaning that its effects will last longer.... | Amphetamine | Wikipedia | 432 | 2504 | https://en.wikipedia.org/wiki/Amphetamine | Biology and health sciences | Drugs and pharmacology | null |
Amphetamine exerts its behavioral effects by altering the use of monoamines as neuronal signals in the brain, primarily in catecholamine neurons in the reward and executive function pathways of the brain. The concentrations of the main neurotransmitters involved in reward circuitry and executive functioning, dopamine a... | Amphetamine | Wikipedia | 375 | 2504 | https://en.wikipedia.org/wiki/Amphetamine | Biology and health sciences | Drugs and pharmacology | null |
In addition to the neuronal monoamine transporters, amphetamine also inhibits both vesicular monoamine transporters, VMAT1 and VMAT2, as well as SLC1A1, SLC22A3, and SLC22A5. SLC1A1 is excitatory amino acid transporter 3 (EAAT3), a glutamate transporter located in neurons, SLC22A3 is an extraneuronal monoamine transpor... | Amphetamine | Wikipedia | 464 | 2504 | https://en.wikipedia.org/wiki/Amphetamine | Biology and health sciences | Drugs and pharmacology | null |
Dopamine
In certain brain regions, amphetamine increases the concentration of dopamine in the synaptic cleft. Amphetamine can enter the presynaptic neuron either through or by diffusing across the neuronal membrane directly. As a consequence of DAT uptake, amphetamine produces competitive reuptake inhibition at the tr... | Amphetamine | Wikipedia | 491 | 2504 | https://en.wikipedia.org/wiki/Amphetamine | Biology and health sciences | Drugs and pharmacology | null |
Serotonin
Amphetamine exerts analogous, yet less pronounced, effects on serotonin as on dopamine and norepinephrine. Amphetamine affects serotonin via and, like norepinephrine, is thought to phosphorylate via . Like dopamine, amphetamine has low, micromolar affinity at the human 5-HT1A receptor.
Other neurotransmitt... | Amphetamine | Wikipedia | 424 | 2504 | https://en.wikipedia.org/wiki/Amphetamine | Biology and health sciences | Drugs and pharmacology | null |
Pharmacokinetics
The oral bioavailability of amphetamine varies with gastrointestinal pH; it is well absorbed from the gut, and bioavailability is typically 90%. Amphetamine is a weak base with a pKa of 9.9; consequently, when the pH is basic, more of the drug is in its lipid soluble free base form, and more is absorbe... | Amphetamine | Wikipedia | 412 | 2504 | https://en.wikipedia.org/wiki/Amphetamine | Biology and health sciences | Drugs and pharmacology | null |
CYP2D6, dopamine β-hydroxylase (DBH), flavin-containing monooxygenase 3 (FMO3), butyrate-CoA ligase (XM-ligase), and glycine N-acyltransferase (GLYAT) are the enzymes known to metabolize amphetamine or its metabolites in humans. Amphetamine has a variety of excreted metabolic products, including , , , benzoic acid, hip... | Amphetamine | Wikipedia | 502 | 2504 | https://en.wikipedia.org/wiki/Amphetamine | Biology and health sciences | Drugs and pharmacology | null |
Amphetamine has a very similar structure and function to the endogenous trace amines, which are naturally occurring neuromodulator molecules produced in the human body and brain. Among this group, the most closely related compounds are phenethylamine, the parent compound of amphetamine, and , a structural isomer of amp... | Amphetamine | Wikipedia | 451 | 2504 | https://en.wikipedia.org/wiki/Amphetamine | Biology and health sciences | Drugs and pharmacology | null |
The substituted derivatives of amphetamine, or "substituted amphetamines", are a broad range of chemicals that contain amphetamine as a "backbone"; specifically, this chemical class includes derivative compounds that are formed by replacing one or more hydrogen atoms in the amphetamine core structure with substituents.... | Amphetamine | Wikipedia | 438 | 2504 | https://en.wikipedia.org/wiki/Amphetamine | Biology and health sciences | Drugs and pharmacology | null |
A large number of alternative synthetic routes to amphetamine have been developed based on classic organic reactions. One example is the Friedel–Crafts alkylation of benzene by allyl chloride to yield beta chloropropylbenzene which is then reacted with ammonia to produce racemic amphetamine (method 2). Another example ... | Amphetamine | Wikipedia | 315 | 2504 | https://en.wikipedia.org/wiki/Amphetamine | Biology and health sciences | Drugs and pharmacology | null |
Detection in body fluids
Amphetamine is frequently measured in urine or blood as part of a drug test for sports, employment, poisoning diagnostics, and forensics. Techniques such as immunoassay, which is the most common form of amphetamine test, may cross-react with a number of sympathomimetic drugs. Chromatographic me... | Amphetamine | Wikipedia | 454 | 2504 | https://en.wikipedia.org/wiki/Amphetamine | Biology and health sciences | Drugs and pharmacology | null |
Amphetamine was first synthesized in 1887 in Germany by Romanian chemist Lazăr Edeleanu who named it phenylisopropylamine; its stimulant effects remained unknown until 1927, when it was independently resynthesized by Gordon Alles and reported to have sympathomimetic properties. Amphetamine had no medical use until late... | Amphetamine | Wikipedia | 408 | 2504 | https://en.wikipedia.org/wiki/Amphetamine | Biology and health sciences | Drugs and pharmacology | null |
Legal status
As a result of the United Nations 1971 Convention on Psychotropic Substances, amphetamine became a schedule II controlled substance, as defined in the treaty, in all 183 state parties. Consequently, it is heavily regulated in most countries. Some countries, such as South Korea and Japan, have banned substi... | Amphetamine | Wikipedia | 486 | 2504 | https://en.wikipedia.org/wiki/Amphetamine | Biology and health sciences | Drugs and pharmacology | null |
Fieldnotes refer to qualitative notes recorded by scientists or researchers in the course of field research, during or after their observation of a specific organism or phenomenon they are studying. The notes are intended to be read as evidence that gives meaning and aids in the understanding of the phenomenon. Fieldno... | Fieldnotes | Wikipedia | 461 | 4083803 | https://en.wikipedia.org/wiki/Fieldnotes | Physical sciences | Research methods | Basics and measurement |
Inscription – where the writer records notes, impressions, and potentially important keywords.
Transcription – where the author writes down dictated local text
Description – a reflective type of writing that synthesizes previous observations and analysis for a later situation in which a more coherent conclusion can b... | Fieldnotes | Wikipedia | 508 | 4083803 | https://en.wikipedia.org/wiki/Fieldnotes | Physical sciences | Research methods | Basics and measurement |
The technique has four main parts:
A field-worthy notebook where one records direct observations as they are being observed.
A larger more substantial journal containing written entries on observations and information, transcribed from the smaller field notebook as soon as possible.
Species accounts of the notes taken... | Fieldnotes | Wikipedia | 196 | 4083803 | https://en.wikipedia.org/wiki/Fieldnotes | Physical sciences | Research methods | Basics and measurement |
Create vivid images: Focus on recording vivid descriptions of actions that take place in the field, instead of recording an interpretation of them. This is particularly important early in the research process. Immediately trying to interpret events can lead to premature conclusions that can prevent later insight when m... | Fieldnotes | Wikipedia | 479 | 4083803 | https://en.wikipedia.org/wiki/Fieldnotes | Physical sciences | Research methods | Basics and measurement |
Verify notes during collection: Converting fieldnotes as described above will likely lead the researcher to discover key points and themes that can then be checked while still present in the field. If conflicting themes are emerging, further data collection can be directed in a manner to help resolve the discrepancy.
... | Fieldnotes | Wikipedia | 181 | 4083803 | https://en.wikipedia.org/wiki/Fieldnotes | Physical sciences | Research methods | Basics and measurement |
The saltwater crocodile (Crocodylus porosus) is a crocodilian native to saltwater habitats, brackish wetlands and freshwater rivers from India's east coast across Southeast Asia and the Sundaland to northern Australia and Micronesia. It has been listed as Least Concern on the IUCN Red List since 1996. It was hunted for... | Saltwater crocodile | Wikipedia | 507 | 566405 | https://en.wikipedia.org/wiki/Saltwater%20crocodile | Biology and health sciences | Crocodilia | Animals |
Currently, the saltwater crocodile is considered a monotypic species.
Evolution
Fossil remains of a saltwater crocodile excavated in northern Queensland were dated to the Pliocene. The saltwater crocodile's closest extant (living) relatives are the Siamese crocodile and the mugger crocodile.
The genus Crocodylus was... | Saltwater crocodile | Wikipedia | 416 | 566405 | https://en.wikipedia.org/wiki/Saltwater%20crocodile | Biology and health sciences | Crocodilia | Animals |
Young saltwater crocodiles are pale yellow in colour with black stripes and spots on their bodies and tails. This colouration lasts for several years until the crocodiles mature into adults. The colour as an adult is much darker greenish-drab, with a few lighter tan or grey areas sometimes apparent. Several colour vari... | Saltwater crocodile | Wikipedia | 478 | 566405 | https://en.wikipedia.org/wiki/Saltwater%20crocodile | Biology and health sciences | Crocodilia | Animals |
Male size
An adult male saltwater crocodile, from young adults to older individuals, typically ranges in length and weighs . On average, adult males range in length and weigh . However average size largely depends on the location, habitat, and human interactions and thus varies from one study to another. In 1993, in... | Saltwater crocodile | Wikipedia | 99 | 566405 | https://en.wikipedia.org/wiki/Saltwater%20crocodile | Biology and health sciences | Crocodilia | Animals |
The largest confirmed saltwater crocodile on record drowned in a fishing net in Papua New Guinea, in 1979. Its dried skin plus head measured in length and it was estimated to have been when accounting for shrinkage and a missing tail tip. Projected from their skull lengths, multiple specimens from Singapore were esti... | Saltwater crocodile | Wikipedia | 459 | 566405 | https://en.wikipedia.org/wiki/Saltwater%20crocodile | Biology and health sciences | Crocodilia | Animals |
Female size
Adult females typically measure from in total length and weigh . Large mature females reach and weigh up to . The largest female on record measured about in total length. Female are thus similar in size to other species of large crocodiles and average slightly smaller than females of some other species, ... | Saltwater crocodile | Wikipedia | 430 | 566405 | https://en.wikipedia.org/wiki/Saltwater%20crocodile | Biology and health sciences | Crocodilia | Animals |
Bait is any appetizing substance (e.g. food) used to attract prey when hunting or fishing, most commonly in the form of trapping (e.g. mousetrap and bird trap), ambushing (e.g. from a hunting blind) and angling.
Baiting is a ubiquitous practice in both recreational (especially angling) and commercial fishing, but the ... | Bait (luring substance) | Wikipedia | 500 | 566692 | https://en.wikipedia.org/wiki/Bait%20%28luring%20substance%29 | Technology | Hunting and fishing | null |
Poisoned bait is a common method for controlling rats, mice, birds, slugs, snails, ants, cockroaches, and other pests. The basic granules, or other formulation, contains a food attractant for the target species and a suitable poison. For ants, a slow-acting toxin is needed so that the workers have time to carry the sub... | Bait (luring substance) | Wikipedia | 233 | 566692 | https://en.wikipedia.org/wiki/Bait%20%28luring%20substance%29 | Technology | Hunting and fishing | null |
In electrochemistry, standard electrode potential , or , is a measure of the reducing power of any element or compound. The IUPAC "Gold Book" defines it as; "the value of the standard emf (electromotive force) of a cell in which molecular hydrogen under standard pressure is oxidized to solvated protons at the left-han... | Standard electrode potential | Wikipedia | 473 | 566959 | https://en.wikipedia.org/wiki/Standard%20electrode%20potential | Physical sciences | Electrochemistry | Chemistry |
A reversible electrode is an electrode that owes its potential to changes of a reversible nature. A first condition to be fulfilled is that the system is close to the chemical equilibrium. A second set of conditions is that the system is submitted to very small solicitations spread on a sufficient period of time so, th... | Standard electrode potential | Wikipedia | 500 | 566959 | https://en.wikipedia.org/wiki/Standard%20electrode%20potential | Physical sciences | Electrochemistry | Chemistry |
In a galvanic cell, where a spontaneous redox reaction drives the cell to produce an electric potential, Gibbs free energy must be negative, in accordance with the following equation:
(unit: Joule = Coulomb × Volt)
where is number of moles of electrons per mole of products and is the Faraday constant, .
A... | Standard electrode potential | Wikipedia | 200 | 566959 | https://en.wikipedia.org/wiki/Standard%20electrode%20potential | Physical sciences | Electrochemistry | Chemistry |
The sea otter (Enhydra lutris) is a marine mammal native to the coasts of the northern and eastern North Pacific Ocean. Adult sea otters typically weigh between , making them the heaviest members of the weasel family, but among the smallest marine mammals. Unlike most marine mammals, the sea otter's primary form of ins... | Sea otter | Wikipedia | 385 | 567471 | https://en.wikipedia.org/wiki/Sea%20otter | Biology and health sciences | Carnivora | null |
Evolution
The sea otter is the heaviest (the giant otter is longer, but significantly slimmer) member of the family Mustelidae, a diverse group that includes the 13 otter species and terrestrial animals such as weasels, badgers, and minks. It is unique among the mustelids in not making dens or burrows, in having no fu... | Sea otter | Wikipedia | 179 | 567471 | https://en.wikipedia.org/wiki/Sea%20otter | Biology and health sciences | Carnivora | null |
Fossil evidence indicates the Enhydra lineage became isolated in the North Pacific approximately 2 million years ago, giving rise to the now-extinct Enhydra macrodonta and the modern sea otter, Enhydra lutris. One related species has been described, Enhydra reevei, from the Pleistocene of East Anglia. The modern sea ot... | Sea otter | Wikipedia | 469 | 567471 | https://en.wikipedia.org/wiki/Sea%20otter | Biology and health sciences | Carnivora | null |
Previously, it was suspected that sea otters came from the same evolutionary branch as earless seals, such as harbor and monk seals. Sea Otters have experienced numerous population bottlenecks throughout their history, with significant numbers being wiped out 9,000-10,000 generations ago and 300–700 generations ago, lo... | Sea otter | Wikipedia | 364 | 567471 | https://en.wikipedia.org/wiki/Sea%20otter | Biology and health sciences | Carnivora | null |
Subspecies
Three subspecies of the sea otter are recognized with distinct geographical distributions. Enhydra lutris lutris (nominate), the Asian sea otter, ranges across Russia's Kuril Islands northeast of Japan, and the Commander Islands in the northwestern Pacific Ocean. In the eastern Pacific Ocean, E. l. kenyoni,... | Sea otter | Wikipedia | 297 | 567471 | https://en.wikipedia.org/wiki/Sea%20otter | Biology and health sciences | Carnivora | null |
Unlike most other marine mammals, the sea otter has no blubber and relies on its exceptionally thick fur to keep warm. With up to , its fur is the densest of any animal. The fur consists of long, waterproof guard hairs and short underfur; the guard hairs keep the dense underfur layer dry. There is an air compartment be... | Sea otter | Wikipedia | 387 | 567471 | https://en.wikipedia.org/wiki/Sea%20otter | Biology and health sciences | Carnivora | null |
The sea otter presents an insight into the evolutionary process of the mammalian invasion of the aquatic environment, which has occurred numerous times over the course of mammalian evolution. Having only returned to the sea about 3 million years ago, sea otters represent a snapshot at the earliest point of the transiti... | Sea otter | Wikipedia | 501 | 567471 | https://en.wikipedia.org/wiki/Sea%20otter | Biology and health sciences | Carnivora | null |
An adult's 32 teeth, particularly the molars, are flattened and rounded for crushing rather than cutting food. Seals and sea otters are the only carnivores with two pairs of lower incisor teeth rather than three; the adult dental formula is . The teeth and bones are sometimes stained purple as a result of ingesting sea... | Sea otter | Wikipedia | 411 | 567471 | https://en.wikipedia.org/wiki/Sea%20otter | Biology and health sciences | Carnivora | null |
The sea otter hunts in short dives, often to the sea floor. Although it can hold its breath for up to five minutes, its dives typically last about one minute and not more than four minutes. It is the only marine animal capable of lifting and turning over rocks, which it often does with its front paws when searching for... | Sea otter | Wikipedia | 479 | 567471 | https://en.wikipedia.org/wiki/Sea%20otter | Biology and health sciences | Carnivora | null |
A male sea otter is most likely to mate if he maintains a breeding territory in an area that is also favored by females. As autumn is the peak breeding season in most areas, males typically defend their territory only from spring to autumn. During this time, males patrol the boundaries of their territories to exclude o... | Sea otter | Wikipedia | 498 | 567471 | https://en.wikipedia.org/wiki/Sea%20otter | Biology and health sciences | Carnivora | null |
Nursing lasts six to eight months in Californian populations and four to twelve months in Alaska, with the mother beginning to offer bits of prey at one to two months. The milk from a sea otter's two abdominal nipples is rich in fat and more similar to the milk of other marine mammals than to that of other mustelids. A... | Sea otter | Wikipedia | 478 | 567471 | https://en.wikipedia.org/wiki/Sea%20otter | Biology and health sciences | Carnivora | null |
Sea otters live in coastal waters deep, and usually stay within a kilometre ( mi) of the shore. They are found most often in areas with protection from the most severe ocean winds, such as rocky coastlines, thick kelp forests, and barrier reefs. Although they are most strongly associated with rocky substrates, sea ott... | Sea otter | Wikipedia | 443 | 567471 | https://en.wikipedia.org/wiki/Sea%20otter | Biology and health sciences | Carnivora | null |
Russia
Currently, the most stable and secure part of the western sea otter's range is along the Russian Far East coastline, in the northwestern Pacific waters off of the country (namely Kamchatka and Sakhalin Island), occasionally being seen in and around the Sea of Okhotsk. Before the 19th century, around 20,000 to 2... | Sea otter | Wikipedia | 457 | 567471 | https://en.wikipedia.org/wiki/Sea%20otter | Biology and health sciences | Carnivora | null |
Alaska
Alaska is the central area of the sea otter's range. In 1973, the population in Alaska was estimated at between 100,000 and 125,000 animals. By 2006, though, the Alaska population had fallen to an estimated 73,000 animals. A massive decline in sea otter populations in the Aleutian Islands accounts for most of t... | Sea otter | Wikipedia | 453 | 567471 | https://en.wikipedia.org/wiki/Sea%20otter | Biology and health sciences | Carnivora | null |
The historic population of California sea otters was estimated at 16,000 before the fur trade decimated the population, leading to their assumed extinction. Today's population of California sea otters are the descendants of a single colony of about 50 sea otters located near Bixby Creek Bridge in March 1938. Their prin... | Sea otter | Wikipedia | 355 | 567471 | https://en.wikipedia.org/wiki/Sea%20otter | Biology and health sciences | Carnivora | null |
In the late 1980s, the USFWS relocated about 140 southern sea otters to San Nicolas Island in southern California, in the hope of establishing a reserve population should the mainland be struck by an oil spill. To the surprise of biologists, the majority of the San Nicolas sea otters swam back to the mainland. Another ... | Sea otter | Wikipedia | 210 | 567471 | https://en.wikipedia.org/wiki/Sea%20otter | Biology and health sciences | Carnivora | null |
When the USFWS implemented the translocation program, it also attempted, in 1986, to implement "zonal management" of the Californian population. To manage the competition between sea otters and fisheries, it declared an "otter-free zone" stretching from Point Conception to the Mexican border. In this zone, only San Nic... | Sea otter | Wikipedia | 315 | 567471 | https://en.wikipedia.org/wiki/Sea%20otter | Biology and health sciences | Carnivora | null |
Although the southern sea otter's range has continuously expanded from the remnant population of about 50 individuals in Big Sur since protection in 1911, from 2007 to 2010, the otter population and its range contracted and since 2010 has made little progress. As of spring 2010, the northern boundary had moved from abo... | Sea otter | Wikipedia | 253 | 567471 | https://en.wikipedia.org/wiki/Sea%20otter | Biology and health sciences | Carnivora | null |
For southern sea otters to be considered for removal from threatened species listing, the U.S. Fish and Wildlife Service (USFWS) determined that the population should exceed 3,090 for three consecutive years. In response to recovery efforts, the population climbed steadily from the mid-20th century through the early 20... | Sea otter | Wikipedia | 293 | 567471 | https://en.wikipedia.org/wiki/Sea%20otter | Biology and health sciences | Carnivora | null |
Mexico
Historian Adele Ogden described sea otters as being particularly abundant in "Lower California", now the Baja California Peninsula, where "seven bays...were main centers". The southernmost limit was Punta Morro Hermoso about south of Punta Eugenia, in turn a headland at the southwestern end of Sebastián Vizcaí... | Sea otter | Wikipedia | 336 | 567471 | https://en.wikipedia.org/wiki/Sea%20otter | Biology and health sciences | Carnivora | null |
Sea otters are apex predators that consume over 100 prey species. In most of its range, the sea otter's diet consists almost exclusively of marine benthic invertebrates, including sea urchins (such as Strongylocentrotus franciscanus and S. purpuratus), sea cucumbers, fat innkeeper worms, crustaceans, a variety of mollu... | Sea otter | Wikipedia | 415 | 567471 | https://en.wikipedia.org/wiki/Sea%20otter | Biology and health sciences | Carnivora | null |
The individuals within a particular area often differ in their foraging methods and prey types, and tend to follow the same patterns as their mothers. The diet of local populations also changes over time, as sea otters can significantly deplete populations of highly preferred prey such as large sea urchins, and prey av... | Sea otter | Wikipedia | 481 | 567471 | https://en.wikipedia.org/wiki/Sea%20otter | Biology and health sciences | Carnivora | null |
Predators
The leading mammalian predators of this species is the orca. Sea lions and bald eagles may prey on pups. On land, young sea otters may face attack from bears and coyotes. In California, great white sharks are their primary predator, though this is the result of mistaking otters for seals and they do not cons... | Sea otter | Wikipedia | 301 | 567471 | https://en.wikipedia.org/wiki/Sea%20otter | Biology and health sciences | Carnivora | null |
In the early 18th century, Russians began to hunt sea otters in the Kuril Islands and sold them to the Chinese at Kyakhta. Russia was also exploring the far northern Pacific at this time, and sent Vitus Bering to map the Arctic coast and find routes from Siberia to North America. In 1741, on his second North Pacific vo... | Sea otter | Wikipedia | 467 | 567471 | https://en.wikipedia.org/wiki/Sea%20otter | Biology and health sciences | Carnivora | null |
Other nations joined in the hunt in the south. Along the coasts of what is now Mexico and California, Spanish explorers bought sea otter pelts from Native Americans and sold them in Asia. In 1778, British explorer Captain James Cook reached Vancouver Island and bought sea otter furs from the First Nations people. When ... | Sea otter | Wikipedia | 432 | 567471 | https://en.wikipedia.org/wiki/Sea%20otter | Biology and health sciences | Carnivora | null |
During the 20th century, sea otter numbers rebounded in about two-thirds of their historic range, a recovery considered one of the greatest successes in marine conservation. However, the IUCN still lists the sea otter as an endangered species, and describes the significant threats to sea otters as oil pollution, predat... | Sea otter | Wikipedia | 303 | 567471 | https://en.wikipedia.org/wiki/Sea%20otter | Biology and health sciences | Carnivora | null |
The small geographic ranges of the sea otter populations in California, Washington, and British Columbia mean a single major spill could be catastrophic for that state or province. Prevention of oil spills and preparation to rescue otters if one happens is a major focus for conservation efforts. Increasing the size and... | Sea otter | Wikipedia | 494 | 567471 | https://en.wikipedia.org/wiki/Sea%20otter | Biology and health sciences | Carnivora | null |
In the Aleutian Islands, a massive and unexpected disappearance of sea otters has occurred in recent decades. In the 1980s, the area was home to an estimated 55,000 to 100,000 sea otters, but the population fell to around 6,000 animals by 2000. The most widely accepted, but still controversial, hypothesis is that kille... | Sea otter | Wikipedia | 455 | 567471 | https://en.wikipedia.org/wiki/Sea%20otter | Biology and health sciences | Carnivora | null |
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