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Several prenatal and perinatal complications have been reported as possible risk factors for autism. These risk factors include maternal gestational diabetes, maternal and paternal age over 30, bleeding during pregnancy after the first trimester, use of certain prescription medication (e.g. valproate) during pregnancy,... | Autism | Wikipedia | 477 | 29113700 | https://en.wikipedia.org/wiki/Autism | Biology and health sciences | Mental disorder | null |
Two versions of the vaccine causation hypothesis were that autism results from brain damage caused by either the MMR vaccine itself, or by mercury used as a vaccine preservative. No convincing scientific evidence supports these claims. They are biologically implausible, and further evidence continues to refute them, in... | Autism | Wikipedia | 382 | 29113700 | https://en.wikipedia.org/wiki/Autism | Biology and health sciences | Mental disorder | null |
Research exploring the evolutionary benefits of autism and associated genes has suggested that autistic people may have played a "unique role in technological spheres and understanding of natural systems" in the course of human development. It has been suggested that autism may have arisen as "a slight trade off for ot... | Autism | Wikipedia | 510 | 29113700 | https://en.wikipedia.org/wiki/Autism | Biology and health sciences | Mental disorder | null |
Pathophysiology
Diagnosis
Conditions correlated or comorbid to autism
Autism is correlated or comorbid with several personality traits/disorders. Comorbidity may increase with age and may worsen the course of youth with ASDs and make intervention and treatment more difficult. Distinguishing between ASDs and other d... | Autism | Wikipedia | 219 | 29113700 | https://en.wikipedia.org/wiki/Autism | Biology and health sciences | Mental disorder | null |
The most common medical condition occurring in autistic people is seizure disorder or epilepsy, which occurs in 11–39% of autistic people. The risk varies with age, cognitive level, and type of language disorder.
Tuberous sclerosis, an autosomal dominant genetic condition in which non-malignant tumors grow in the brai... | Autism | Wikipedia | 502 | 29113700 | https://en.wikipedia.org/wiki/Autism | Biology and health sciences | Mental disorder | null |
Deficits in ASD are often linked to behavior problems, such as difficulties following directions, being cooperative, and doing things on other people's terms. Symptoms similar to those of ADHD can be part of an ASD diagnosis.
Sensory processing disorder is also comorbid with ASD, with comorbidity rates of 42–88%.
Sta... | Autism | Wikipedia | 509 | 29113700 | https://en.wikipedia.org/wiki/Autism | Biology and health sciences | Mental disorder | null |
Management
There is no treatment as such for autism, and many sources advise that this is not an appropriate goal, although treatment of co-occurring conditions remains an important goal. There is no cure for autism, nor can any of the known treatments significantly reduce brain mutations caused by autism, although t... | Autism | Wikipedia | 495 | 29113700 | https://en.wikipedia.org/wiki/Autism | Biology and health sciences | Mental disorder | null |
There has been increasing attention to the development of evidence-based interventions for autistic young children. Three theoretical frameworks outlined for early childhood intervention include applied behavior analysis (ABA), the developmental social-pragmatic model (DSP) and cognitive behavioral therapy (CBT). Altho... | Autism | Wikipedia | 473 | 29113700 | https://en.wikipedia.org/wiki/Autism | Biology and health sciences | Mental disorder | null |
ASD treatment generally focuses on behavioral and educational interventions to target its two core symptoms: social communication deficits and restricted, repetitive behaviors. If symptoms continue after behavioral strategies have been implemented, some medications can be recommended to target specific symptoms or co-e... | Autism | Wikipedia | 476 | 29113700 | https://en.wikipedia.org/wiki/Autism | Biology and health sciences | Mental disorder | null |
Similarly, a teacher-implemented intervention that utilizes a more naturalistic form of ABA combined with a developmental social pragmatic approach has been found to be beneficial in improving social-communication skills in young children, although there is less evidence in its treatment of global symptoms. Neuropsycho... | Autism | Wikipedia | 110 | 29113700 | https://en.wikipedia.org/wiki/Autism | Biology and health sciences | Mental disorder | null |
Pharmacological interventions
Medications may be used to treat ASD symptoms that interfere with integrating a child into home or school when behavioral treatment fails. They may also be used for associated health problems, such as ADHD, anxiety, or if the person is hurting themself or aggressive with others, but their... | Autism | Wikipedia | 482 | 29113700 | https://en.wikipedia.org/wiki/Autism | Biology and health sciences | Mental disorder | null |
Although popularly used as an alternative treatment for autistic people, there is no good evidence to recommend a gluten- and casein-free diet as a standard treatment. A 2018 review concluded that it may be a therapeutic option for specific groups of children with autism, such as those with known food intolerances or ... | Autism | Wikipedia | 448 | 29113700 | https://en.wikipedia.org/wiki/Autism | Biology and health sciences | Mental disorder | null |
Results of a systematic review on interventions to address health outcomes among autistic adults found emerging evidence to support mindfulness-based interventions for improving mental health. This includes decreasing stress, anxiety, ruminating thoughts, anger, and aggression. An updated Cochrane review (2022) found e... | Autism | Wikipedia | 467 | 29113700 | https://en.wikipedia.org/wiki/Autism | Biology and health sciences | Mental disorder | null |
While rates of ASD are consistent across cultures, they vary greatly by gender, with boys diagnosed far more frequently than girls: 1 in 70 boys, but only 1 in 315 girls at eight years of age. Girls, however, are more likely to have associated cognitive impairment, suggesting that less severe forms of ASD are likely be... | Autism | Wikipedia | 462 | 29113700 | https://en.wikipedia.org/wiki/Autism | Biology and health sciences | Mental disorder | null |
In 2020, the Centers for Disease Control's Autism and Developmental Disabilities Monitoring (ADDM) Network reported that approximately 1 in 54 children in the United States (1 in 34 boys, and 1 in 144 girls) is diagnosed with an autism spectrum disorder (ASD), based on data collected in 2016. This estimate is a 10% inc... | Autism | Wikipedia | 440 | 29113700 | https://en.wikipedia.org/wiki/Autism | Biology and health sciences | Mental disorder | null |
An autistic culture has emerged, accompanied by the autistic rights and neurodiversity movements, that argues autism should be accepted as a difference to be accommodated instead of cured, although a minority of autistic people might still accept a cure. Worldwide, events related to autism include World Autism Awarenes... | Autism | Wikipedia | 359 | 29113700 | https://en.wikipedia.org/wiki/Autism | Biology and health sciences | Mental disorder | null |
Autism rights or neurodiversity advocates believe that the autism spectrum is genetic and should be accepted as a natural variation in the human genome. These movements are not without detractors; a common argument against neurodiversity activists is that most of them have relatively low support needs, or are self-diag... | Autism | Wikipedia | 448 | 29113700 | https://en.wikipedia.org/wiki/Autism | Biology and health sciences | Mental disorder | null |
The puzzle symbol is controversial among autism advocates and rejected by many. It has been criticized as outdated, now that autism is better understood, as well as implying that autistic people are mysterious or incomplete, and for its association with Autism Speaks. The autism rights movement and neurodiversity advoc... | Autism | Wikipedia | 485 | 29113700 | https://en.wikipedia.org/wiki/Autism | Biology and health sciences | Mental disorder | null |
A (; from the Latin word ) is an amphitheatre-like valley formed by glacial erosion. Alternative names for this landform are corrie (from , meaning a pot or cauldron) and ; ). A cirque may also be a similarly shaped landform arising from fluvial erosion.
The concave shape of a glacial cirque is open on the downhill s... | Cirque | Wikipedia | 464 | 945670 | https://en.wikipedia.org/wiki/Cirque | Physical sciences | Glacial landforms | Earth science |
Cirques form in conditions which are favorable; in the Northern Hemisphere the conditions include the north-east slope, where they are protected from the majority of the Sun's energy and from the prevailing winds. These areas are sheltered from heat, encouraging the accumulation of snow; if the accumulation of snow inc... | Cirque | Wikipedia | 506 | 945670 | https://en.wikipedia.org/wiki/Cirque | Physical sciences | Glacial landforms | Earth science |
Where cirques form one behind the other, a cirque stairway results, as at the Zastler Loch in the Black Forest.
As glaciers can only originate above the snowline, studying the location of present-day cirques provides information on past glaciation patterns and on climate change.
Fluvial-erosion cirque formation
Alth... | Cirque | Wikipedia | 320 | 945670 | https://en.wikipedia.org/wiki/Cirque | Physical sciences | Glacial landforms | Earth science |
Australia
Blue Lake Cirque, New South Wales, Australia
Asia
Chandra Taal, Himachal Pradesh, India
Cirque Valley, Hindu Kush, Pakistan
Karasawa Cirque, Kamikōchi, Mount Hotakadake, Hida Mountains, Japan
Makhtesh Ramon, Negev desert, Israel
Senjōjiki Cirque, Mount Hōken, Kiso Mountains, Japan
Western Cwm, Khumbu Hi... | Cirque | Wikipedia | 350 | 945670 | https://en.wikipedia.org/wiki/Cirque | Physical sciences | Glacial landforms | Earth science |
Acanthodii or acanthodians is an extinct class of gnathostomes (jawed fishes). They are currently considered to represent a paraphyletic grade of various fish lineages basal to extant Chondrichthyes, which includes living sharks, rays, and chimaeras. Acanthodians possess a mosaic of features shared with both osteichthy... | Acanthodii | Wikipedia | 314 | 945696 | https://en.wikipedia.org/wiki/Acanthodii | Biology and health sciences | Fishes | null |
Acanthodians have been divided into four orders: Acanthodiformes, Climatiiformes, Diplacanthiformes, and Ischnacanthiformes. "Climatiiformes" is a paraphyletic assemblage of early acanthodians such as climatiids, gyracanthids, and diplacanthids; they had robust bony shoulder girdles and many small sharp spines ("interm... | Acanthodii | Wikipedia | 459 | 945696 | https://en.wikipedia.org/wiki/Acanthodii | Biology and health sciences | Fishes | null |
Many palaeontologists originally considered the acanthodians close to the ancestors of the bony fishes. Although their interior skeletons were made of cartilage, a bonelike material had developed in the skins of these fishes, in the form of closely fitting scales (see above). Some scales were greatly enlarged and forme... | Acanthodii | Wikipedia | 441 | 945696 | https://en.wikipedia.org/wiki/Acanthodii | Biology and health sciences | Fishes | null |
Evolutionary history
The oldest remains attributed acanthodian-grade chondrichthyans are Fanjingshania and Qianodus from the Early Silurian of China, dating to around 439 million years ago. Compared to other contemporary groups of fish, acanthodians were relatively morphologically and ecologically conservative. Acanth... | Acanthodii | Wikipedia | 177 | 945696 | https://en.wikipedia.org/wiki/Acanthodii | Biology and health sciences | Fishes | null |
In mathematical logic, New Foundations (NF) is a non-well-founded, finitely axiomatizable set theory conceived by Willard Van Orman Quine as a simplification of the theory of types of Principia Mathematica.
Definition
The well-formed formulas of NF are the standard formulas of propositional calculus with two primiti... | New Foundations | Wikipedia | 360 | 945957 | https://en.wikipedia.org/wiki/New%20Foundations | Mathematics | Axiomatic systems | null |
Extensionality: If and are sets, and for each object , is an element of if and only if is an element of , then . This can also be viewed as defining the equality symbol.
Singleton: For every object , the set exists, and is called the singleton of .
Cartesian Product: For any sets , , the set , called the Cartes... | New Foundations | Wikipedia | 414 | 945957 | https://en.wikipedia.org/wiki/New%20Foundations | Mathematics | Axiomatic systems | null |
Typed Set Theory
New Foundations is closely related to Russellian unramified typed set theory (TST), a streamlined version of the theory of types of Principia Mathematica with a linear hierarchy of types. In this many-sorted theory, each variable and set is assigned a type. It is customary to write the type indices a... | New Foundations | Wikipedia | 421 | 945957 | https://en.wikipedia.org/wiki/New%20Foundations | Mathematics | Axiomatic systems | null |
TTT is considered a "weird" theory because each type is related to each lower type in the same way. For example, type 2 sets have both type 1 members and type 0 members, and extensionality axioms assert that a type 2 set is determined uniquely by either its type 1 members or its type 0 members. Whereas TST has natural ... | New Foundations | Wikipedia | 494 | 945957 | https://en.wikipedia.org/wiki/New%20Foundations | Mathematics | Axiomatic systems | null |
This section discusses some problematic constructions in NF. For a further development of mathematics in NFU, with a comparison to the development of the same in ZFC, see implementation of mathematics in set theory.
Ordered pairs
Relations and functions are defined in TST (and in NF and NFU) as sets of ordered pairs ... | New Foundations | Wikipedia | 353 | 945957 | https://en.wikipedia.org/wiki/New%20Foundations | Mathematics | Axiomatic systems | null |
Natural numbers and the axiom of infinity
The usual form of the axiom of infinity is based on the von Neumann construction of the natural numbers, which is not suitable for NF, since the description of the successor operation (and many other aspects of von Neumann numerals) is necessarily unstratified. The usual form ... | New Foundations | Wikipedia | 500 | 945957 | https://en.wikipedia.org/wiki/New%20Foundations | Mathematics | Axiomatic systems | null |
In NF (without urelements), Specker has shown that the axiom of choice is false. Since it can be proved through induction that every finite set has a choice function (a stratified condition), it follows that is infinite.
In NFU with axioms asserting the existence of a type-level ordered pair, is equinumerous with it... | New Foundations | Wikipedia | 508 | 945957 | https://en.wikipedia.org/wiki/New%20Foundations | Mathematics | Axiomatic systems | null |
Resolution of set-theoretic paradoxes
NF may seem to run afoul of problems similar to those in naive set theory, but this is not the case. For example, the existence of the impossible Russell class is not an axiom of NF, because cannot be stratified. NF steers clear of the three well-known paradoxes of set theory i... | New Foundations | Wikipedia | 438 | 945957 | https://en.wikipedia.org/wiki/New%20Foundations | Mathematics | Axiomatic systems | null |
The usual way to correct such a type problem is to replace with , the set of one-element subsets of . Indeed, the correctly typed version of Cantor's theorem is a theorem in TST (thanks to the diagonalization argument), and thus also a theorem in NF. In particular, : there are fewer one-element sets than sets (and so... | New Foundations | Wikipedia | 376 | 945957 | https://en.wikipedia.org/wiki/New%20Foundations | Mathematics | Axiomatic systems | null |
To formalize the Burali-Forti paradox in NF, it is necessary to first formalize the concept of ordinal numbers. In NF, ordinals are defined (in the same way as in naive set theory) as equivalence classes of well-orderings under isomorphism. This is a stratified definition, so the set of ordinals can be defined with no... | New Foundations | Wikipedia | 482 | 945957 | https://en.wikipedia.org/wiki/New%20Foundations | Mathematics | Axiomatic systems | null |
Another (stratified) statement that can be proven by transfinite induction is that T is a strictly monotone (order-preserving) operation on the ordinals, i.e., iff . Hence the T operation is not a function: The collection of ordinals cannot have a least member, and thus cannot be a set. More concretely, the monotonic... | New Foundations | Wikipedia | 319 | 945957 | https://en.wikipedia.org/wiki/New%20Foundations | Mathematics | Axiomatic systems | null |
Although NFU resolves the paradoxes similarly to NF, it has a much simpler consistency proof. The proof can be formalized within Peano Arithmetic (PA), a theory weaker than ZF that most mathematicians accept without question. This does not conflict with Gödel's second incompleteness theorem because NFU does not include... | New Foundations | Wikipedia | 388 | 945957 | https://en.wikipedia.org/wiki/New%20Foundations | Mathematics | Axiomatic systems | null |
It may now be proved that this actually is a model of NFU. Let be a stratified formula in the language of NFU. Choose an assignment of types to all variables in the formula which witnesses the fact that it is stratified. Choose a natural number N greater than all types assigned to variables by this stratification. Exp... | New Foundations | Wikipedia | 450 | 945957 | https://en.wikipedia.org/wiki/New%20Foundations | Mathematics | Axiomatic systems | null |
Self-sufficiency of mathematical foundations in NFU
For philosophical reasons, it is important to note that it is not necessary to work in ZFC or any related system to carry out this proof. A common argument against the use of NFU as a foundation for mathematics is that the reasons for relying on it have to do with th... | New Foundations | Wikipedia | 399 | 945957 | https://en.wikipedia.org/wiki/New%20Foundations | Mathematics | Axiomatic systems | null |
Facts about the automorphism j
The automorphism j of a model of this kind is closely related to certain natural operations in NFU. For example, if W is a well-ordering in the nonstandard model (we suppose here that we use Kuratowski pairs so that the coding of functions in the two theories will agree to some extent) w... | New Foundations | Wikipedia | 316 | 945957 | https://en.wikipedia.org/wiki/New%20Foundations | Mathematics | Axiomatic systems | null |
In 1914, Norbert Wiener showed how to code the ordered pair as a set of sets, making it possible to eliminate the relation types of Principia Mathematica in favor of the linear hierarchy of sets in TST. The usual definition of the ordered pair was first proposed by Kuratowski in 1921. Willard Van Orman Quine first prop... | New Foundations | Wikipedia | 421 | 945957 | https://en.wikipedia.org/wiki/New%20Foundations | Mathematics | Axiomatic systems | null |
In 1983, Marcel Crabbé proved consistent a system he called NFI, whose axioms are unrestricted extensionality and those instances of comprehension in which no variable is assigned a type higher than that of the set asserted to exist. This is a predicativity restriction, though NFI is not a predicative theory: it admits... | New Foundations | Wikipedia | 481 | 945957 | https://en.wikipedia.org/wiki/New%20Foundations | Mathematics | Axiomatic systems | null |
Orpiment, also known as ″yellow arsenic blende″ is a deep-colored, orange-yellow arsenic sulfide mineral with formula . It is found in volcanic fumaroles, low-temperature hydrothermal veins, and hot springs and may be formed through sublimation.
Orpiment takes its name from the Latin auripigmentum (aurum, "gold" + pig... | Orpiment | Wikipedia | 493 | 946319 | https://en.wikipedia.org/wiki/Orpiment | Physical sciences | Minerals | Earth science |
Orpiment and realgar
Orpiment and realgar are closely related minerals and are often categorized in the same group. They are both arsenic sulfides and belong to the monoclinic crystal system. They are found in the same deposits and can form in the same geologic environments. As a result, Orpiment and realgar share sim... | Orpiment | Wikipedia | 424 | 946319 | https://en.wikipedia.org/wiki/Orpiment | Physical sciences | Minerals | Earth science |
Historical and regional use of orpiment
In Egypt, lumps of orpiment pigment have been found in a fourteenth-century BC tomb. In China, orpiment is known to have been used to color Chinese lacquer, despite no written sources mentioning this. Orpiment has also been identified on Central Asian wall paintings from the six... | Orpiment | Wikipedia | 487 | 946319 | https://en.wikipedia.org/wiki/Orpiment | Physical sciences | Minerals | Earth science |
Other historical uses
Orpiment was traded in the Roman Empire and was used as a medicine in China, even though it is very toxic. It has been used as fly poison and to tip arrows with poison. Because of its striking color, it was of interest to alchemists, both in China and Europe, searching for a way to make gold. It ... | Orpiment | Wikipedia | 329 | 946319 | https://en.wikipedia.org/wiki/Orpiment | Physical sciences | Minerals | Earth science |
In geometry, a straight line, usually abbreviated line, is an infinitely long object with no width, depth, or curvature, an idealization of such physical objects as a straightedge, a taut string, or a ray of light. Lines are spaces of dimension one, which may be embedded in spaces of dimension two, three, or higher. Th... | Line (geometry) | Wikipedia | 473 | 946975 | https://en.wikipedia.org/wiki/Line%20%28geometry%29 | Mathematics | Geometry and topology | null |
On a Euclidean plane, a line can be represented as a boundary between two regions. Any collection of finitely many lines partitions the plane into convex polygons (possibly unbounded); this partition is known as an arrangement of lines.
In higher dimensions
In three-dimensional space, a first degree equation in the va... | Line (geometry) | Wikipedia | 450 | 946975 | https://en.wikipedia.org/wiki/Line%20%28geometry%29 | Mathematics | Geometry and topology | null |
In Euclidean geometry, the Euclidean distance d(a,b) between two points a and b may be used to express the collinearity between three points by:
The points a, b and c are collinear if and only if d(x,a) = d(c,a) and d(x,b) = d(c,b) implies x = c.
However, there are other notions of distance (such as the Manhattan dista... | Line (geometry) | Wikipedia | 472 | 946975 | https://en.wikipedia.org/wiki/Line%20%28geometry%29 | Mathematics | Geometry and topology | null |
Parallel lines are lines in the same plane that never cross. Intersecting lines share a single point in common. Coincidental lines coincide with each other—every point that is on either one of them is also on the other.
Perpendicular lines are lines that intersect at right angles.
In three-dimensional space, skew lin... | Line (geometry) | Wikipedia | 498 | 946975 | https://en.wikipedia.org/wiki/Line%20%28geometry%29 | Mathematics | Geometry and topology | null |
or
In two dimensions, the equation for non-vertical lines is often given in the slope–intercept form:
where:
m is the slope or gradient of the line.
b is the y-intercept of the line.
x is the independent variable of the function .
The slope of the line through points and , when , is given by and the equation of ... | Line (geometry) | Wikipedia | 508 | 946975 | https://en.wikipedia.org/wiki/Line%20%28geometry%29 | Mathematics | Geometry and topology | null |
Vectors
The vector equation of the line through points A and B is given by (where λ is a scalar).
If a is vector OA and b is vector OB, then the equation of the line can be written: .
A ray starting at point A is described by limiting λ. One ray is obtained if λ ≥ 0, and the opposite ray comes from λ ≤ 0.
Polar coo... | Line (geometry) | Wikipedia | 416 | 946975 | https://en.wikipedia.org/wiki/Line%20%28geometry%29 | Mathematics | Geometry and topology | null |
When a geometry is described by a set of axioms, the notion of a line is usually left undefined (a so-called primitive object). The properties of lines are then determined by the axioms which refer to them. One advantage to this approach is the flexibility it gives to users of the geometry. Thus in differential geometr... | Line (geometry) | Wikipedia | 474 | 946975 | https://en.wikipedia.org/wiki/Line%20%28geometry%29 | Mathematics | Geometry and topology | null |
Given distinct points A and B, they determine a unique ray with initial point A. As two points define a unique line, this ray consists of all the points between A and B (including A and B) and all the points C on the line through A and B such that B is between A and C. This is, at times, also expressed as the set of al... | Line (geometry) | Wikipedia | 507 | 946975 | https://en.wikipedia.org/wiki/Line%20%28geometry%29 | Mathematics | Geometry and topology | null |
A bird nest is the spot in which a bird lays and incubates its eggs and raises its young. Although the term popularly refers to a specific structure made by the bird itself—such as the grassy cup nest of the American robin or Eurasian blackbird, or the elaborately woven hanging nest of the Montezuma oropendola or the v... | Bird nest | Wikipedia | 471 | 947038 | https://en.wikipedia.org/wiki/Bird%20nest | Biology and health sciences | Shelters and structures | Animals |
Not every bird species builds or uses a nest. Some auks, for instance—including common murre, thick-billed murre and razorbill—lay their eggs directly onto the narrow rocky ledges they use as breeding sites. The eggs of these species are dramatically pointed at one end, so that they roll in a circle when disturbed. Thi... | Bird nest | Wikipedia | 430 | 947038 | https://en.wikipedia.org/wiki/Bird%20nest | Biology and health sciences | Shelters and structures | Animals |
The simplest nest construction is the scrape, which is merely a shallow depression in soil or vegetation. This nest type, which typically has a rim deep enough to keep the eggs from rolling away, is sometimes lined with bits of vegetation, small stones, shell fragments or feathers. These materials may help to camouflag... | Bird nest | Wikipedia | 510 | 947038 | https://en.wikipedia.org/wiki/Bird%20nest | Biology and health sciences | Shelters and structures | Animals |
In warm climates, such as deserts and salt flats, heat rather than cold can kill the developing embryos. In such places, scrapes are shallower and tend to be lined with non-vegetative material (including shells, feathers, sticks and soil), which allows convective cooling to occur as air moves over the eggs. Some specie... | Bird nest | Wikipedia | 438 | 947038 | https://en.wikipedia.org/wiki/Bird%20nest | Biology and health sciences | Shelters and structures | Animals |
Burying eggs as a form of incubation reaches its zenith with the Australasian megapodes. Several megapode species construct enormous mound nests made of soil, branches, sticks, twigs and leaves, and lay their eggs within the rotting mass. The heat generated by these mounds, which are in effect giant compost heaps, warm... | Bird nest | Wikipedia | 262 | 947038 | https://en.wikipedia.org/wiki/Bird%20nest | Biology and health sciences | Shelters and structures | Animals |
Both the temperature and the moisture content of the mound are critical to the survival and development of the eggs, so both are carefully regulated for the entire length of the breeding season (which may last for as long as eight months), principally by the male. Ornithologists believe that megapodes may use sensitive... | Bird nest | Wikipedia | 472 | 947038 | https://en.wikipedia.org/wiki/Bird%20nest | Biology and health sciences | Shelters and structures | Animals |
The base of the horned coot's enormous nest is a mound built of stones, gathered one at a time by the pair, using their beaks. These stones, which may weigh as much as 450 g (about a pound) each, are dropped into the shallow water of a lake, making a cone-shaped pile which can measure as much as at the bottom and at ... | Bird nest | Wikipedia | 324 | 947038 | https://en.wikipedia.org/wiki/Bird%20nest | Biology and health sciences | Shelters and structures | Animals |
Most burrow nesting species dig a horizontal tunnel into a vertical (or nearly vertical) dirt cliff, with a chamber at the tunnel's end to house the eggs. The length of the tunnel varies depending on the substrate and the species; sand martins make relatively short tunnels ranging from , for example, while those of the... | Bird nest | Wikipedia | 485 | 947038 | https://en.wikipedia.org/wiki/Bird%20nest | Biology and health sciences | Shelters and structures | Animals |
Predation levels on some burrow-nesting species can be quite high; on Alaska's Wooded Islands, for example, river otters munched their way through some 23 percent of the island's fork-tailed storm-petrel population during a single breeding season in 1977. There is some evidence that increased vulnerability may lead som... | Bird nest | Wikipedia | 343 | 947038 | https://en.wikipedia.org/wiki/Bird%20nest | Biology and health sciences | Shelters and structures | Animals |
Woodpeckers use their chisel-like bills to excavate their cavity nests, a process which takes, on average, about two weeks. Cavities are normally excavated on the downward-facing side of a branch, presumably to make it more difficult for predators to access the nest, and to reduce the chance that rain floods the nest. ... | Bird nest | Wikipedia | 440 | 947038 | https://en.wikipedia.org/wiki/Bird%20nest | Biology and health sciences | Shelters and structures | Animals |
Cavity-dwelling species have to contend with the danger of predators accessing their nest, catching them and their young inside and unable to get out. They have a variety of methods for decreasing the likelihood of this happening. Red-cockaded woodpeckers peel bark around the entrance, and drill wells above and below t... | Bird nest | Wikipedia | 448 | 947038 | https://en.wikipedia.org/wiki/Bird%20nest | Biology and health sciences | Shelters and structures | Animals |
Many swifts and some hummingbirds use thick, quick-drying saliva to anchor their nests. The chimney swift starts by dabbing two globs of saliva onto the wall of a chimney or tree trunk. In flight, it breaks a small twig from a tree and presses it into the saliva, angling the twig downwards so that the central part of t... | Bird nest | Wikipedia | 464 | 947038 | https://en.wikipedia.org/wiki/Bird%20nest | Biology and health sciences | Shelters and structures | Animals |
The sphere nest is a roundish structure; it is completely enclosed, except for a small opening which allows access. Most spherical nests are woven out of plant material. Spider webs are also frequently used, upon which other material such as lichens may be stuck for camouflage. The cape penduline tit incorporates false... | Bird nest | Wikipedia | 506 | 947038 | https://en.wikipedia.org/wiki/Bird%20nest | Biology and health sciences | Shelters and structures | Animals |
Some birds use pieces of snake slough in their nests. It has been suggested that these may deter some nest predators such as squirrels.
Colonial nesting
Though most birds nest individually, some species—including seabirds, penguins, flamingos, many herons, gulls, terns, weaver, some corvids and some sparrows—gather t... | Bird nest | Wikipedia | 473 | 947038 | https://en.wikipedia.org/wiki/Bird%20nest | Biology and health sciences | Shelters and structures | Animals |
In the 19th and early 20th centuries, naturalists often collected bird's eggs and their nests. The practice of egg-collecting or oology is now illegal in many jurisdictions worldwide; the study of bird nests is called caliology.
Artificial bird nests
Bird nests are also built by humans to help in the conservation of ... | Bird nest | Wikipedia | 153 | 947038 | https://en.wikipedia.org/wiki/Bird%20nest | Biology and health sciences | Shelters and structures | Animals |
Dredging is the excavation of material from a water environment. Possible reasons for dredging include improving existing water features; reshaping land and water features to alter drainage, navigability, and commercial use; constructing dams, dikes, and other controls for streams and shorelines; and recovering valuabl... | Dredging | Wikipedia | 404 | 947692 | https://en.wikipedia.org/wiki/Dredging | Technology | Hydraulic infrastructure | null |
History
Ancient authors refer to harbour dredging. The seven arms of the Nile were channelled and wharfs built at the time of the pyramids (4000 BC), there was extensive harbour building in the eastern Mediterranean from 1000 BC and the disturbed sediment layers gives evidence of dredging. At Marseille, dredging phases... | Dredging | Wikipedia | 258 | 947692 | https://en.wikipedia.org/wiki/Dredging | Technology | Hydraulic infrastructure | null |
Purposes
Capital dredging: dredging carried out to create a new harbour, berth or waterway, or to deepen existing facilities in order to allow larger ships access. Because capital works usually involve hard material or high-volume works, the work is usually done using a cutter suction dredge or large trailing suction h... | Dredging | Wikipedia | 456 | 947692 | https://en.wikipedia.org/wiki/Dredging | Technology | Hydraulic infrastructure | null |
Contaminant remediation: to reclaim areas affected by chemical spills, storm water surges (with urban runoff), and other soil contaminations, including silt from sewage sludge and from decayed matter, like wilted plants. Disposal becomes a proportionally large factor in these operations.
Flood prevention: dredging inc... | Dredging | Wikipedia | 83 | 947692 | https://en.wikipedia.org/wiki/Dredging | Technology | Hydraulic infrastructure | null |
Other
Beach nourishment: this is mining sand offshore and placing on a beach to replace sand eroded by storms or wave action. This enhances the recreational and protective function of the beach, which are also eroded by human activity. This is typically performed by a cutter-suction dredge or trailing suction hopper ... | Dredging | Wikipedia | 446 | 947692 | https://en.wikipedia.org/wiki/Dredging | Technology | Hydraulic infrastructure | null |
the largest trailing suction hopper dredgers in the world were Jan De Nul's Cristobal Colon (launched 4 July 2008) and her sister ship Leiv Eriksson (launched 4 September 2009). Main design specifications for the Cristobal Colon and the Leiv Eriksson are: 46,000 cubic metre hopper and a design dredging depth of 155 m.... | Dredging | Wikipedia | 495 | 947692 | https://en.wikipedia.org/wiki/Dredging | Technology | Hydraulic infrastructure | null |
A grab dredger picks up seabed material with a clam shell bucket, which hangs from an onboard crane or a crane barge, or is carried by a hydraulic arm, or is mounted like on a dragline. This technique is often used in excavation of bay mud. Most of these dredges are crane barges with spuds, steel piles that can be lowe... | Dredging | Wikipedia | 511 | 947692 | https://en.wikipedia.org/wiki/Dredging | Technology | Hydraulic infrastructure | null |
A water injection dredger uses a small jet to inject water under low pressure (to prevent the sediment from exploding into the surrounding waters) into the seabed to bring the sediment in suspension, which then becomes a turbidity current, which flows away down slope, is moved by a second burst of water from the WID or... | Dredging | Wikipedia | 499 | 947692 | https://en.wikipedia.org/wiki/Dredging | Technology | Hydraulic infrastructure | null |
As of June 2018, the largest dredger in Asia is , a long dredger constructed in China, with a capacity of . An even larger dredger, retired in 1980, was the U.S. Army Corps of Engineers , which was long. The , a clamshell dredger that maintains levees in San Francisco Bay, has operated continuously since being built... | Dredging | Wikipedia | 504 | 947692 | https://en.wikipedia.org/wiki/Dredging | Technology | Hydraulic infrastructure | null |
A number of vessels, notably in the UK and NW Europe de-water the hopper to dry the cargo to enable it to be discharged onto a quayside 'dry'. This is achieved principally using self discharge bucket wheel, drag scraper or excavator via conveyor systems.
When contaminated (toxic) sediments are to be removed, or large ... | Dredging | Wikipedia | 409 | 947692 | https://en.wikipedia.org/wiki/Dredging | Technology | Hydraulic infrastructure | null |
Dredging can have numerous significant impacts on the environment, including the following:
Release of toxic chemicals (including heavy metals and PCB) from bottom sediments into the water column.
Short term increases in turbidity, which can affect aquatic species metabolism and interfere with spawning. Suction dredg... | Dredging | Wikipedia | 425 | 947692 | https://en.wikipedia.org/wiki/Dredging | Technology | Hydraulic infrastructure | null |
Fell terrier refers to a regional type of long-legged working terrier, not a specific breed of dog.
Description and purpose
Fell terriers are types of small working terriers developed in the fell country of Northern England and used as hunting dogs. They may be crossbred or purebred. Fell terrier types are typically ... | Fell Terrier | Wikipedia | 481 | 948422 | https://en.wikipedia.org/wiki/Fell%20Terrier | Biology and health sciences | Dogs | Animals |
Breeds
Several named breeds have been developed from the fell terrier type, such as the Border Terrier, Lakeland Terrier, Patterdale Terrier, scorrier terrier, Welsh Terrier, and other locally developed breeds. All are sometimes called "fell terrier" interchangeably with their breed name. The "National Terriers Club L... | Fell Terrier | Wikipedia | 147 | 948422 | https://en.wikipedia.org/wiki/Fell%20Terrier | Biology and health sciences | Dogs | Animals |
Afrocarpus is a genus of conifer of the family Podocarpaceae. Two to six species are recognized. They are evergreen trees native to Africa. Afrocarpus was designated a genus in 1989, when several species formerly classified in Podocarpus and Nageia were reclassified.
Taxonomy
Afrocarpus gaussenii was based on a single... | Afrocarpus | Wikipedia | 401 | 948821 | https://en.wikipedia.org/wiki/Afrocarpus | Biology and health sciences | Pinophyta (Conifers) | Plants |
The female seed cones are solitary. Their peduncles may have small scale leaves. The cones consist of several sterile cone scales and one fertile cone scale with just one seed producing ovule. The sterile scales wither as the cone matures, unlike in the closely related genus Podocarpus where the scales fuse to form a f... | Afrocarpus | Wikipedia | 324 | 948821 | https://en.wikipedia.org/wiki/Afrocarpus | Biology and health sciences | Pinophyta (Conifers) | Plants |
The Goliath birdeater (Theraphosa blondi) belongs to the tarantula family Theraphosidae. Found in northern South America, it is the largest spider in the world by mass () and body length (up to ), and second to the giant huntsman spider by leg span. It is also called the Goliath tarantula or Goliath bird-eating spider;... | Goliath birdeater | Wikipedia | 471 | 948919 | https://en.wikipedia.org/wiki/Goliath%20birdeater | Biology and health sciences | Spiders | Animals |
Feeding
Despite its name, the Goliath birdeater only rarely actually preys on birds; in the wild, its diet consists primarily of other large arthropods, worms, and amphibians. However, because of its size and opportunistic predatory behavior, this species commonly kills and consumes a variety of insects and small te... | Goliath birdeater | Wikipedia | 279 | 948919 | https://en.wikipedia.org/wiki/Goliath%20birdeater | Biology and health sciences | Spiders | Animals |
Merbromin (marketed as Mercurochrome, Merbromine, Mercurocol, Sodium mercurescein, Asceptichrome, Supercrome, Brocasept and Cinfacromin) is an organomercuric disodium salt compound used as a topical antiseptic for minor cuts and scrapes and as a biological dye. Readily available in most countries, it is no longer sold... | Merbromin | Wikipedia | 482 | 2095010 | https://en.wikipedia.org/wiki/Merbromin | Physical sciences | Organic salts | Chemistry |
Its antiseptic qualities were discovered in 1918 by Hugh H. Young, a physician at Johns Hopkins Hospital. The chemical soon became popular among parents and physicians for everyday antiseptic uses, in part because the dye component made it easy to see where the antiseptic had been applied.
On 19 October 1998, citing p... | Merbromin | Wikipedia | 217 | 2095010 | https://en.wikipedia.org/wiki/Merbromin | Physical sciences | Organic salts | Chemistry |
The geology of the Moon (sometimes called selenology, although the latter term can refer more generally to "lunar science") is quite different from that of Earth. The Moon lacks a true atmosphere, and the absence of free oxygen and water eliminates erosion due to weather. Instead, the surface is eroded much more slowly... | Geology of the Moon | Wikipedia | 486 | 2096232 | https://en.wikipedia.org/wiki/Geology%20of%20the%20Moon | Physical sciences | Solar System | Astronomy |
The geological history of the Moon has been defined into six major epochs, called the lunar geologic timescale. Starting about 4.5 billion years ago, the newly formed Moon was in a molten state and was orbiting much closer to Earth resulting in tidal forces. These tidal forces deformed the molten body into an ellipsoid... | Geology of the Moon | Wikipedia | 510 | 2096232 | https://en.wikipedia.org/wiki/Geology%20of%20the%20Moon | Physical sciences | Solar System | Astronomy |
Analysis of the samples from the Moon seems to show that a lot of the Moon's impact basins formed in a short amount of time between about 4 and 3.85 Ga ago. This hypothesis is referred to as the lunar cataclysm or late heavy bombardment. However, it is now recognized that ejecta from the Imbrium impact basin (one of th... | Geology of the Moon | Wikipedia | 347 | 2096232 | https://en.wikipedia.org/wiki/Geology%20of%20the%20Moon | Physical sciences | Solar System | Astronomy |
Impacts by meteorites and comets are the only abrupt geologic force acting on the Moon today, though the variation of Earth tides on the scale of the Lunar anomalistic month causes small variations in stresses. Some of the most important craters used in lunar stratigraphy formed in this recent epoch. For example, the c... | Geology of the Moon | Wikipedia | 455 | 2096232 | https://en.wikipedia.org/wiki/Geology%20of%20the%20Moon | Physical sciences | Solar System | Astronomy |
Highlands
The most distinctive aspect of the Moon is the contrast between its bright and dark zones. Lighter surfaces are the lunar highlands, which receive the name of terrae (singular terra, from the Latin for earth, land), and the darker plains are called maria (singular mare, from the Latin for sea), after Johannes... | Geology of the Moon | Wikipedia | 431 | 2096232 | https://en.wikipedia.org/wiki/Geology%20of%20the%20Moon | Physical sciences | Solar System | Astronomy |
A large portion of maria erupted within, or flowed into, the low-lying impact basins on the lunar nearside. However, it is unlikely that a causal relationship exists between the impact event and mare volcanism because the impact basins are much older (by about 500 million years) than the mare fill. Furthermore, Oceanus... | Geology of the Moon | Wikipedia | 434 | 2096232 | https://en.wikipedia.org/wiki/Geology%20of%20the%20Moon | Physical sciences | Solar System | Astronomy |
Rilles
Rilles on the Moon sometimes resulted from the formation of localized lava channels. These generally fall into three categories, consisting of sinuous, arcuate, or linear shapes. By following these meandering rilles back to their source, they often lead to an old volcanic vent. One of the most notable sinuous ri... | Geology of the Moon | Wikipedia | 511 | 2096232 | https://en.wikipedia.org/wiki/Geology%20of%20the%20Moon | Physical sciences | Solar System | Astronomy |
Impact cratering is the most notable geological process on the Moon. The craters are formed when a solid body, such as an asteroid or comet, collides with the surface at a high velocity (mean impact velocities for the Moon are about 17 km per second). The kinetic energy of the impact creates a compression shock wave th... | Geology of the Moon | Wikipedia | 473 | 2096232 | https://en.wikipedia.org/wiki/Geology%20of%20the%20Moon | Physical sciences | Solar System | Astronomy |
The ejecta from large impacts can include large blocks of material that reimpact the surface to form secondary impact craters. These craters are sometimes formed in clearly discernible radial patterns, and generally have shallower depths than primary craters of the same size. In some cases an entire line of these block... | Geology of the Moon | Wikipedia | 490 | 2096232 | https://en.wikipedia.org/wiki/Geology%20of%20the%20Moon | Physical sciences | Solar System | Astronomy |
The regolith contains rocks, fragments of minerals from the original bedrock, and glassy particles formed during the impacts. In most of the lunar regolith, half of the particles are made of mineral fragments fused by the glassy particles; these objects are called agglutinates. The chemical composition of the regolith ... | Geology of the Moon | Wikipedia | 426 | 2096232 | https://en.wikipedia.org/wiki/Geology%20of%20the%20Moon | Physical sciences | Solar System | Astronomy |
The first rocks brought back by Apollo 11 were basalts. Although the mission landed on Mare Tranquillitatis, a few millimetric fragments of rocks coming from the highlands were picked up. These are composed mainly of plagioclase feldspar; some fragments were composed exclusively of anorthite. The identification of thes... | Geology of the Moon | Wikipedia | 395 | 2096232 | https://en.wikipedia.org/wiki/Geology%20of%20the%20Moon | Physical sciences | Solar System | Astronomy |
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