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These species are subdivisions of genus types that can occur in partly unstable air with limited convection. The species castellanus appears when a mostly stable stratocumuliform or cirriform layer becomes disturbed by localized areas of airmass instability, usually in the morning or afternoon. This results in the form... | Cloud | Wikipedia | 445 | 47515 | https://en.wikipedia.org/wiki/Cloud | Physical sciences | Earth science | null |
With highly unstable atmospheric conditions, large cumulus may continue to grow into even more strongly convective cumulonimbus calvus (essentially a very tall congestus cloud that produces thunder), then ultimately into the species capillatus when supercooled water droplets at the top of the cloud turn into ice crysta... | Cloud | Wikipedia | 507 | 47515 | https://en.wikipedia.org/wiki/Cloud | Physical sciences | Earth science | null |
Another variety, duplicatus (closely spaced layers of the same type, one above the other), is sometimes found with cirrus of both the fibratus and uncinus species, and with altocumulus and stratocumulus of the species stratiformis and lenticularis. The variety undulatus (having a wavy undulating base) can occur with an... | Cloud | Wikipedia | 479 | 47515 | https://en.wikipedia.org/wiki/Cloud | Physical sciences | Earth science | null |
When the precipitation reaches the ground without completely evaporating, it is designated as the feature praecipitatio. This normally occurs with altostratus opacus, which can produce widespread but usually light precipitation, and with thicker clouds that show significant vertical development. Of the latter, upward-g... | Cloud | Wikipedia | 511 | 47515 | https://en.wikipedia.org/wiki/Cloud | Physical sciences | Earth science | null |
Several new supplementary features have been formally recognized by the World Meteorological Organization (WMO). The feature fluctus can form under conditions of strong atmospheric wind shear when a stratocumulus, altocumulus, or cirrus cloud breaks into regularly spaced crests. This variant is sometimes known informal... | Cloud | Wikipedia | 499 | 47515 | https://en.wikipedia.org/wiki/Cloud | Physical sciences | Earth science | null |
Clouds initially form in clear air or become clouds when fog rises above surface level. The genus of a newly formed cloud is determined mainly by air mass characteristics such as stability and moisture content. If these characteristics change over time, the genus tends to change accordingly. When this happens, the orig... | Cloud | Wikipedia | 464 | 47515 | https://en.wikipedia.org/wiki/Cloud | Physical sciences | Earth science | null |
Stratocumulus clouds can be organized into "fields" that take on certain specially classified shapes and characteristics. In general, these fields are more discernible from high altitudes than from ground level. They can often be found in the following forms:
Actinoform, which resembles a leaf or a spoked wheel.
Clos... | Cloud | Wikipedia | 480 | 47515 | https://en.wikipedia.org/wiki/Cloud | Physical sciences | Earth science | null |
Divergence is the opposite of convergence. In the Earth's troposphere, it involves the horizontal outflow of air from the upper part of a rising column of air, or from the lower part of a subsiding column often associated with an area or ridge of high pressure. Cloudiness tends to be least prevalent near the poles and ... | Cloud | Wikipedia | 386 | 47515 | https://en.wikipedia.org/wiki/Cloud | Physical sciences | Earth science | null |
As a tropospheric cloud matures, the dense water droplets may combine to produce larger droplets. If the droplets become too large and heavy to be kept aloft by the air circulation, they will fall from the cloud as rain. By this process of accumulation, the space between droplets becomes increasingly larger, permitting... | Cloud | Wikipedia | 331 | 47515 | https://en.wikipedia.org/wiki/Cloud | Physical sciences | Earth science | null |
A cumulonimbus cloud that appears to have a greenish or bluish tint is a sign that it contains extremely high amounts of water; hail or rain which scatter light in a way that gives the cloud a blue color. A green colorization occurs mostly late in the day when the sun is comparatively low in the sky and the incident su... | Cloud | Wikipedia | 440 | 47515 | https://en.wikipedia.org/wiki/Cloud | Physical sciences | Earth science | null |
The complexity and diversity of clouds in the troposphere is a major reason for difficulty in quantifying the effects of clouds on climate and climate change. On the one hand, white cloud tops promote cooling of Earth's surface by reflecting shortwave radiation (visible and near infrared) from the Sun, diminishing the ... | Cloud | Wikipedia | 289 | 47515 | https://en.wikipedia.org/wiki/Cloud | Physical sciences | Earth science | null |
As difficult as it is to evaluate the influences of current clouds on current climate, it is even more problematic to predict changes in cloud patterns and properties in a future, warmer climate, and the resultant cloud influences on future climate. In a warmer climate more water would enter the atmosphere by evaporati... | Cloud | Wikipedia | 420 | 47515 | https://en.wikipedia.org/wiki/Cloud | Physical sciences | Earth science | null |
Supercooled nitric acid and water PSC's, sometimes known as type 1, typically have a stratiform appearance resembling cirrostratus or haze, but because they are not frozen into crystals, do not show the pastel colors of the nacreous types. This type of PSC has been identified as a cause of ozone depletion in the strat... | Cloud | Wikipedia | 488 | 47515 | https://en.wikipedia.org/wiki/Cloud | Physical sciences | Earth science | null |
Distribution in the mesosphere is similar to the stratosphere except at much higher altitudes. Because of the need for maximum cooling of the water vapor to produce noctilucent clouds, their distribution tends to be restricted to polar regions of Earth. Sightings are rare more than 45 degrees south of the north pole o... | Cloud | Wikipedia | 436 | 47515 | https://en.wikipedia.org/wiki/Cloud | Physical sciences | Earth science | null |
Clouds play an important mythical or non-scientific role in various cultures and religious traditions. The ancient Akkadians believed that the clouds (in meteorology, probably the supplementary feature mamma) were the breasts of the sky goddess Antu and that rain was milk from her breasts. In , Yahweh is described as g... | Cloud | Wikipedia | 441 | 47515 | https://en.wikipedia.org/wiki/Cloud | Physical sciences | Earth science | null |
Condensation is the change of the state of matter from the gas phase into the liquid phase, and is the reverse of vaporization. The word most often refers to the water cycle. It can also be defined as the change in the state of water vapor to liquid water when in contact with a liquid or solid surface or cloud conde... | Condensation | Wikipedia | 427 | 47521 | https://en.wikipedia.org/wiki/Condensation | Physical sciences | Phase transitions | null |
Because condensation is a naturally occurring phenomenon, it can often be used to generate water in large quantities for human use. Many structures are made solely for the purpose of collecting water from condensation, such as air wells and fog fences. Such systems can often be used to retain soil moisture in areas whe... | Condensation | Wikipedia | 490 | 47521 | https://en.wikipedia.org/wiki/Condensation | Physical sciences | Phase transitions | null |
Convection is single or multiphase fluid flow that occurs spontaneously through the combined effects of material property heterogeneity and body forces on a fluid, most commonly density and gravity (see buoyancy). When the cause of the convection is unspecified, convection due to the effects of thermal expansion and bu... | Convection | Wikipedia | 343 | 47526 | https://en.wikipedia.org/wiki/Convection | Physical sciences | Fluid mechanics | null |
[...] This motion of heat takes place in three ways, which a common fire-place very well illustrates. If, for instance, we place a thermometer directly before a fire, it soon begins to rise, indicating an increase of temperature. In this case the heat has made its way through the space between the fire and the thermome... | Convection | Wikipedia | 460 | 47526 | https://en.wikipedia.org/wiki/Convection | Physical sciences | Fluid mechanics | null |
Mechanisms
Convection may happen in fluids at all scales larger than a few atoms. There are a variety of circumstances in which the forces required for convection arise, leading to different types of convection, described below. In broad terms, convection arises because of body forces acting within the fluid, such as g... | Convection | Wikipedia | 504 | 47526 | https://en.wikipedia.org/wiki/Convection | Physical sciences | Fluid mechanics | null |
Natural convection will be more likely and more rapid with a greater variation in density between the two fluids, a larger acceleration due to gravity that drives the convection or a larger distance through the convecting medium. Natural convection will be less likely and less rapid with more rapid diffusion (thereby d... | Convection | Wikipedia | 436 | 47526 | https://en.wikipedia.org/wiki/Convection | Physical sciences | Fluid mechanics | null |
Variable salinity in water and variable water content in air masses are frequent causes of convection in the oceans and atmosphere which do not involve heat, or else involve additional compositional density factors other than the density changes from thermal expansion (see thermohaline circulation). Similarly, variable... | Convection | Wikipedia | 425 | 47526 | https://en.wikipedia.org/wiki/Convection | Physical sciences | Fluid mechanics | null |
Convection occurs on a large scale in atmospheres, oceans, planetary mantles, and it provides the mechanism of heat transfer for a large fraction of the outermost interiors of the Sun and all stars. Fluid movement during convection may be invisibly slow, or it may be obvious and rapid, as in a hurricane. On astronomica... | Convection | Wikipedia | 382 | 47526 | https://en.wikipedia.org/wiki/Convection | Physical sciences | Fluid mechanics | null |
A convection cell, also known as a Bénard cell, is a characteristic fluid flow pattern in many convection systems. A rising body of fluid typically loses heat because it encounters a colder surface. In liquid, this occurs because it exchanges heat with colder liquid through direct exchange. In the example of the Earth'... | Convection | Wikipedia | 432 | 47526 | https://en.wikipedia.org/wiki/Convection | Physical sciences | Fluid mechanics | null |
Some more localized phenomena than global atmospheric movement are also due to convection, including wind and some of the hydrologic cycle. For example, a foehn wind is a down-slope wind which occurs on the downwind side of a mountain range. It results from the adiabatic warming of air which has dropped most of its moi... | Convection | Wikipedia | 492 | 47526 | https://en.wikipedia.org/wiki/Convection | Physical sciences | Fluid mechanics | null |
Solar radiation affects the oceans: warm water from the Equator tends to circulate toward the poles, while cold polar water heads towards the Equator. The surface currents are initially dictated by surface wind conditions. The trade winds blow westward in the tropics, and the westerlies blow eastward at mid-latitudes... | Convection | Wikipedia | 430 | 47526 | https://en.wikipedia.org/wiki/Convection | Physical sciences | Fluid mechanics | null |
The Earth's surface is divided into a number of tectonic plates that are continuously being created and consumed at their opposite plate boundaries. Creation (accretion) occurs as mantle is added to the growing edges of a plate. This hot added material cools down by conduction and convection of heat. At the consumption... | Convection | Wikipedia | 402 | 47526 | https://en.wikipedia.org/wiki/Convection | Physical sciences | Fluid mechanics | null |
The Stack effect or chimney effect is the movement of air into and out of buildings, chimneys, flue gas stacks, or other containers due to buoyancy. Buoyancy occurs due to a difference in indoor-to-outdoor air density resulting from temperature and moisture differences. The greater the thermal difference and the height... | Convection | Wikipedia | 481 | 47526 | https://en.wikipedia.org/wiki/Convection | Physical sciences | Fluid mechanics | null |
Another case of this phenomenon is the event of super-cooling, where the water is cooled to below freezing temperatures but does not immediately begin to freeze. Under the same conditions as before, the flow is developed. Afterward, the temperature of the right wall is decreased to −10 °C. This causes the water at that... | Convection | Wikipedia | 490 | 47526 | https://en.wikipedia.org/wiki/Convection | Physical sciences | Fluid mechanics | null |
The relative magnitudes of the Grashof number and the square of the Reynolds number determine which form of convection dominates. If , forced convection may be neglected, whereas if , natural convection may be neglected. If the ratio, known as the Richardson number, is approximately one, then both forced and natural co... | Convection | Wikipedia | 501 | 47526 | https://en.wikipedia.org/wiki/Convection | Physical sciences | Fluid mechanics | null |
Behavior
The Grashof number can be formulated for natural convection occurring due to a concentration gradient, sometimes termed thermo-solutal convection. In this case, a concentration of hot fluid diffuses into a cold fluid, in much the same way that ink poured into a container of water diffuses to dye the entire sp... | Convection | Wikipedia | 471 | 47526 | https://en.wikipedia.org/wiki/Convection | Physical sciences | Fluid mechanics | null |
Note that the above equation differs from the usual expression for Grashof number because the value has been replaced by its approximation , which applies for ideal gases only (a reasonable approximation for air at ambient pressure).
Pattern formation
Convection, especially Rayleigh–Bénard convection, where the conv... | Convection | Wikipedia | 345 | 47526 | https://en.wikipedia.org/wiki/Convection | Physical sciences | Fluid mechanics | null |
The cryosphere is an umbrella term for those portions of Earth's surface where water is in solid form. This includes sea ice, ice on lakes or rivers, snow, glaciers, ice caps, ice sheets, and frozen ground (which includes permafrost). Thus, there is a overlap with the hydrosphere. The cryosphere is an integral part of ... | Cryosphere | Wikipedia | 406 | 47527 | https://en.wikipedia.org/wiki/Cryosphere | Physical sciences | Water: General | null |
Properties and interactions
There are several fundamental physical properties of snow and ice that modulate energy exchanges between the surface and the atmosphere. The most important properties are the surface reflectance (albedo), the ability to transfer heat (thermal diffusivity), and the ability to change state (l... | Cryosphere | Wikipedia | 476 | 47527 | https://en.wikipedia.org/wiki/Cryosphere | Physical sciences | Water: General | null |
The higher albedos for snow and ice cause rapid shifts in surface reflectivity in autumn and spring in high latitudes, but the overall climatic significance of this increase is spatially and temporally modulated by cloud cover. (Planetary albedo is determined principally by cloud cover, and by the small amount of total... | Cryosphere | Wikipedia | 385 | 47527 | https://en.wikipedia.org/wiki/Cryosphere | Physical sciences | Water: General | null |
While snow and ice act to insulate the surface from large energy losses in winter, they also act to retard warming in the spring and summer because of the large amount of energy required to melt ice (the latent heat of fusion, 3.34 x 105 J/kg at 0 °C). However, the strong static stability of the atmosphere over areas o... | Cryosphere | Wikipedia | 512 | 47527 | https://en.wikipedia.org/wiki/Cryosphere | Physical sciences | Water: General | null |
Sea ice covers much of the polar oceans and forms by freezing of sea water. Satellite data since the early 1970s reveal considerable seasonal, regional, and interannual variability in the sea ice covers of both hemispheres. Seasonally, sea-ice extent in the Southern Hemisphere varies by a factor of 5, from a minimum of... | Cryosphere | Wikipedia | 497 | 47527 | https://en.wikipedia.org/wiki/Cryosphere | Physical sciences | Water: General | null |
Ice forms on rivers and lakes in response to seasonal cooling. The sizes of the ice bodies involved are too small to exert anything other than localized climatic effects. However, the freeze-up/break-up processes respond to large-scale and local weather factors, such that considerable interannual variability exists in ... | Cryosphere | Wikipedia | 401 | 47527 | https://en.wikipedia.org/wiki/Cryosphere | Physical sciences | Water: General | null |
Global warming is expected to result in major changes to the partitioning of snow and rainfall, and to the timing of snowmelt, which will have important implications for water use and management. These changes also involve potentially important decadal and longer time-scale feedbacks to the climate system through tempo... | Cryosphere | Wikipedia | 153 | 47527 | https://en.wikipedia.org/wiki/Cryosphere | Physical sciences | Water: General | null |
Cumulonimbus () is a dense, towering, vertical cloud, typically forming from water vapor condensing in the lower troposphere that builds upward carried by powerful buoyant air currents. Above the lower portions of the cumulonimbus the water vapor becomes ice crystals, such as snow and graupel, the interaction of which ... | Cumulonimbus cloud | Wikipedia | 474 | 47530 | https://en.wikipedia.org/wiki/Cumulonimbus%20cloud | Physical sciences | Clouds | null |
Types
Cumulonimbus flammagenitus (pyrocumulonimbus): rapidly growing cloud forming from non-atmospheric heat and condensation nuclei sources such as wildfires and volcanic eruptions.
Supplementary features
Accessory clouds
Arcus (including roll and shelf clouds): low, horizontal cloud formation associated with the... | Cumulonimbus cloud | Wikipedia | 312 | 47530 | https://en.wikipedia.org/wiki/Cumulonimbus%20cloud | Physical sciences | Clouds | null |
Cumulonimbus storm cells can produce torrential rain of a convective nature (often in the form of a rain shaft) and flash flooding, as well as straight-line winds. Most storm cells die after about 20 minutes, when the precipitation causes more downdraft than updraft, causing the energy to dissipate. If there is suffici... | Cumulonimbus cloud | Wikipedia | 446 | 47530 | https://en.wikipedia.org/wiki/Cumulonimbus%20cloud | Physical sciences | Clouds | null |
In general, cumulonimbus require moisture, an unstable air mass, and a lifting force in order to form. Cumulonimbus typically go through three stages: the developing stage, the mature stage (where the main cloud may reach supercell status in favorable conditions), and the dissipation stage. The average thunderstorm has... | Cumulonimbus cloud | Wikipedia | 211 | 47530 | https://en.wikipedia.org/wiki/Cumulonimbus%20cloud | Physical sciences | Clouds | null |
Cumulus clouds are clouds that have flat bases and are often described as puffy, cotton-like, or fluffy in appearance. Their name derives from the Latin , meaning "heap" or "pile". Cumulus clouds are low-level clouds, generally less than in altitude unless they are the more vertical cumulus congestus form. Cumulus clo... | Cumulus cloud | Wikipedia | 435 | 47532 | https://en.wikipedia.org/wiki/Cumulus%20cloud | Physical sciences | Clouds | null |
In this phase, water vapor condenses on various nuclei present in the air, forming the cumulus cloud. This creates the characteristic flat-bottomed puffy shape associated with cumulus clouds. The height of the cloud (from its bottom to its top) depends on the temperature profile of the atmosphere and of the presence of... | Cumulus cloud | Wikipedia | 457 | 47532 | https://en.wikipedia.org/wiki/Cumulus%20cloud | Physical sciences | Clouds | null |
The height at which the cloud forms depends on the amount of moisture in the thermal that forms the cloud. Humid air will generally result in a lower cloud base. In temperate areas, the base of the cumulus clouds is usually below above ground level, but it can range up to in altitude. In arid and mountainous areas, t... | Cumulus cloud | Wikipedia | 411 | 47532 | https://en.wikipedia.org/wiki/Cumulus%20cloud | Physical sciences | Clouds | null |
The species Cumulus fractus is ragged in appearance and can form in clear air as a precursor to cumulus humilis and larger cumulus species-types; or it can form in precipitation as the supplementary feature pannus (also called scud) which can also include stratus fractus of bad weather. Cumulus humilis clouds look like... | Cumulus cloud | Wikipedia | 454 | 47532 | https://en.wikipedia.org/wiki/Cumulus%20cloud | Physical sciences | Clouds | null |
Due to reflectivity, clouds cool the earth by around , an effect largely caused by stratocumulus clouds. However, at the same time, they heat the earth by around by reflecting emitted radiation, an effect largely caused by cirrus clouds. This averages out to a net loss of . Cumulus clouds, on the other hand, have a va... | Cumulus cloud | Wikipedia | 374 | 47532 | https://en.wikipedia.org/wiki/Cumulus%20cloud | Physical sciences | Clouds | null |
Cirrocumulus clouds form in patches and cannot cast shadows. They commonly appear in regular, rippling patterns or in rows of clouds with clear areas between. Cirrocumulus are, like other members of the cumuliform and stratocumuliform categories, formed via convective processes. Significant growth of these patches indi... | Cumulus cloud | Wikipedia | 440 | 47532 | https://en.wikipedia.org/wiki/Cumulus%20cloud | Physical sciences | Clouds | null |
A stratocumulus cloud is another type of stratocumuliform cloud. Like cumulus clouds, they form at low levels and via convection. However, unlike cumulus clouds, their growth is almost completely retarded by a strong inversion. As a result, they flatten out like stratus clouds, giving them a layered appearance. These c... | Cumulus cloud | Wikipedia | 443 | 47532 | https://en.wikipedia.org/wiki/Cumulus%20cloud | Physical sciences | Clouds | null |
The haptophytes, classified either as the Haptophyta, Haptophytina or Prymnesiophyta (named for Prymnesium), are a clade of algae.
The names Haptophyceae or Prymnesiophyceae are sometimes used instead. This ending implies classification at the class rank rather than as a division. Although the phylogenetics of this gr... | Haptophyte | Wikipedia | 428 | 47535 | https://en.wikipedia.org/wiki/Haptophyte | Biology and health sciences | Other organisms | null |
The best-known haptophytes are coccolithophores, which make up 673 of the 762 described haptophyte species, and have an exoskeleton of calcareous plates called coccoliths. Coccolithophores are some of the most abundant marine phytoplankton, especially in the open ocean, and are extremely abundant as microfossils, formi... | Haptophyte | Wikipedia | 372 | 47535 | https://en.wikipedia.org/wiki/Haptophyte | Biology and health sciences | Other organisms | null |
Subphylum Haptophytina Cavalier-Smith 2015 [Haptophyta Hibberd 1976 sensu Ruggerio et al. 2015]
Clade Rappemonada Kim et al. 2011
Class Rappephyceae Cavalier-Smith 2015
Order Rappemonadales
Family Rappemonadaceae
Clade Haptomonada (Margulis & Schwartz 1998) [Haptophyta Hibberd 1976 emend. Edvardsen & Eikrem 2000; ... | Haptophyte | Wikipedia | 506 | 47535 | https://en.wikipedia.org/wiki/Haptophyte | Biology and health sciences | Other organisms | null |
Family Phaeocystaceae Lagerheim 1896
Order Prymnesiales Papenfuss 1955 emend. Edvardsen and Eikrem 2000
Family Chrysochromulinaceae Edvardsen, Eikrem & Medlin 2011
Family Prymnesiaceae Conrad 1926 ex Schmidt 1931
Subclass Calcihaptophycidae
Order Isochrysidales Pascher 1910 [Prinsiales Young & Bown 1997]
Family †... | Haptophyte | Wikipedia | 494 | 47535 | https://en.wikipedia.org/wiki/Haptophyte | Biology and health sciences | Other organisms | null |
Order †Podorhabdales Rood 1971 [Biscutales Aubry 2009; Prediscosphaerales Aubry 2009] (non-imbricating or radial placolith)
Family †Axopodorhabdaceae Wind & Wise 1977 [Podorhabdaceae Noel 1965]
Family †Biscutaceae Black, 1971
Family †Calyculaceae Noel 1973
Family †Cretarhabdaceae Thierstein 1973
Family †Mazaganel... | Haptophyte | Wikipedia | 248 | 47535 | https://en.wikipedia.org/wiki/Haptophyte | Biology and health sciences | Other organisms | null |
The carrying capacity of an environment is the maximum population size of a biological species that can be sustained by that specific environment, given the food, habitat, water, and other resources available. The carrying capacity is defined as the environment's maximal load, which in population ecology corresponds to... | Carrying capacity | Wikipedia | 503 | 47544 | https://en.wikipedia.org/wiki/Carrying%20capacity | Biology and health sciences | Ecology | Biology |
Neo-Malthusians and eugenicists popularised the use of the words to describe the number of people the Earth can support in the 1950s, although American biostatisticians Raymond Pearl and Lowell Reed had already applied it in these terms to human populations in the 1920s.
Hadwen and Palmer (1923) defined carrying capac... | Carrying capacity | Wikipedia | 510 | 47544 | https://en.wikipedia.org/wiki/Carrying%20capacity | Biology and health sciences | Ecology | Biology |
This equation is a modification of the original Verhulst model:
In this equation, the carrying capacity , , is
When the Verhulst model is plotted into a graph, the population change over time takes the form of a sigmoid curve, reaching its highest level at . This is the logistic growth curve and it is calculate... | Carrying capacity | Wikipedia | 358 | 47544 | https://en.wikipedia.org/wiki/Carrying%20capacity | Biology and health sciences | Ecology | Biology |
Agriculture
It is important for farmers to calculate the carrying capacity of their land so they can establish a sustainable stocking rate. For example, calculating the carrying capacity of a paddock in Australia is done in Dry Sheep Equivalents (DSEs). A single DSE is 50 kg Merino wether, dry ewe or non-pregnant ewe,... | Carrying capacity | Wikipedia | 500 | 47544 | https://en.wikipedia.org/wiki/Carrying%20capacity | Biology and health sciences | Ecology | Biology |
This system can also be applied to natural areas. Grazing megaherbivores at roughly 1 GV/ha is considered sustainable in central European grasslands, although this varies widely depending on many factors. In ecology it is theoretically (i.e. cyclic succession, patch dynamics, Megaherbivorenhypothese) taken that a grazi... | Carrying capacity | Wikipedia | 466 | 47544 | https://en.wikipedia.org/wiki/Carrying%20capacity | Biology and health sciences | Ecology | Biology |
In fisheries, carrying capacity is used in the formulae to calculate sustainable yields for fisheries management. The maximum sustainable yield (MSY) is defined as "the highest average catch that can be continuously taken from an exploited population (=stock) under average environmental conditions". MSY was originally ... | Carrying capacity | Wikipedia | 501 | 47544 | https://en.wikipedia.org/wiki/Carrying%20capacity | Biology and health sciences | Ecology | Biology |
Recent technological successes, however, have come at grave environmental costs. Climate change, ocean acidification, and the huge dead zones at the mouths of many of world's great rivers, are a function of the scale of contemporary agriculture and the many other demands 8 billion people make on the planet. Scientists ... | Carrying capacity | Wikipedia | 442 | 47544 | https://en.wikipedia.org/wiki/Carrying%20capacity | Biology and health sciences | Ecology | Biology |
One issue with applying carrying capacity to any species is that ecosystems are not constant and change over time, therefore changing the resources available. Research has shown that sometimes the presence of human populations can increase local biodiversity, demonstrating that human habitation does not always lead to ... | Carrying capacity | Wikipedia | 397 | 47544 | https://en.wikipedia.org/wiki/Carrying%20capacity | Biology and health sciences | Ecology | Biology |
Millennium ecosystem assessment
The Millennium Ecosystem Assessment (MEA) of 2005 was a massive, collaborative effort to assess the state of Earth's ecosystems, involving more than 1,300 experts worldwide. Their first two of four main findings were the following. The first finding is:Over the past 50 years, humans hav... | Carrying capacity | Wikipedia | 275 | 47544 | https://en.wikipedia.org/wiki/Carrying%20capacity | Biology and health sciences | Ecology | Biology |
Critiques of Carrying Capacity with Relation to Humans
Humans and human culture itself are highly adaptable things that have overcome issues that seemed incomprehensible at the time before. It is not to say that carrying capacity is not something that should be considered and thought about, but it should be taken with... | Carrying capacity | Wikipedia | 291 | 47544 | https://en.wikipedia.org/wiki/Carrying%20capacity | Biology and health sciences | Ecology | Biology |
Ecological Footprint accounting measures the demands people make on nature and compares them to available supplies, for both individual countries and the world as a whole. Developed originally by Mathis Wackernagel and William Rees, it has been refined and applied in a variety of contexts over the years by Global Footp... | Carrying capacity | Wikipedia | 495 | 47544 | https://en.wikipedia.org/wiki/Carrying%20capacity | Biology and health sciences | Ecology | Biology |
For the rest of the year, we are maintaining our ecological deficit by drawing down local resource stocks and accumulating carbon dioxide in the atmosphere. We are operating in overshoot.The concept of ‘ecological overshoot’ can be seen as equivalent to exceeding human carrying capacity. According to the most recent ca... | Carrying capacity | Wikipedia | 89 | 47544 | https://en.wikipedia.org/wiki/Carrying%20capacity | Biology and health sciences | Ecology | Biology |
This includes countries with dense populations (such as China, India, and the Philippines), countries with high per capita consumption and resource use (France, Germany, and Saudi Arabia), and countries with both high per capita consumption and large numbers of people (Japan, the United Kingdom, and the United States). | Carrying capacity | Wikipedia | 63 | 47544 | https://en.wikipedia.org/wiki/Carrying%20capacity | Biology and health sciences | Ecology | Biology |
Planetary Boundaries Framework
According to its developers, the planetary boundaries framework defines “a safe operating space for humanity based on the intrinsic biophysical processes that regulate the stability of the Earth system.” Human civilization has evolved in the relative stability of the Holocene epoch; cros... | Carrying capacity | Wikipedia | 425 | 47544 | https://en.wikipedia.org/wiki/Carrying%20capacity | Biology and health sciences | Ecology | Biology |
Daylight saving time (DST), also referred to as daylight saving(s), daylight savings time, daylight time (United States and Canada), or summer time (United Kingdom, European Union, and others), is the practice of advancing clocks to make better use of the longer daylight available during summer so that darkness falls a... | Daylight saving time | Wikipedia | 480 | 47548 | https://en.wikipedia.org/wiki/Daylight%20saving%20time | Technology | Timekeeping | null |
Industrialized societies usually follow a clock-based schedule for daily activities that do not change throughout the course of the year. The time of day that individuals begin and end work or school, and the coordination of mass transit, for example, usually remain constant year-round. In contrast, an agrarian society... | Daylight saving time | Wikipedia | 468 | 47548 | https://en.wikipedia.org/wiki/Daylight%20saving%20time | Technology | Timekeeping | null |
Variation within a time zone
The effect of daylight saving time also varies according to how far east or west the location is within its time zone, with locations farther east inside the time zone benefiting more from DST than locations farther west in the same time zone. In spite of a width spanning thousands of kilom... | Daylight saving time | Wikipedia | 467 | 47548 | https://en.wikipedia.org/wiki/Daylight%20saving%20time | Technology | Timekeeping | null |
New Zealand entomologist George Hudson first proposed modern DST. His shift-work job gave him spare time to collect insects and led him to value after-hours daylight. In 1895, he presented a paper to the Wellington Philosophical Society proposing a two-hour daylight-saving shift, and considerable interest was expressed... | Daylight saving time | Wikipedia | 450 | 47548 | https://en.wikipedia.org/wiki/Daylight%20saving%20time | Technology | Timekeeping | null |
It is a common myth in the United States that DST was first implemented for the benefit of farmers. In reality, farmers have been one of the strongest lobbying groups against DST since it was first implemented. The factors that influence farming schedules, such as morning dew and dairy cattle's readiness to be milked, ... | Daylight saving time | Wikipedia | 459 | 47548 | https://en.wikipedia.org/wiki/Daylight%20saving%20time | Technology | Timekeeping | null |
In most countries that observe seasonal daylight saving time, clocks revert in winter to "standard time". An exception exists in Ireland, where its winter clock has the same offset (UTC+00:00) and legal name as that in Britain (Greenwich Mean Time)—but while its summer clock also has the same offset as Britain's (UTC+0... | Daylight saving time | Wikipedia | 367 | 47548 | https://en.wikipedia.org/wiki/Daylight%20saving%20time | Technology | Timekeeping | null |
The dates on which clocks change vary with location and year; consequently, the time differences between regions also vary throughout the year. For example, Central European Time is usually six hours ahead of North American Eastern Time, except for a few weeks in March and October/November, while the United Kingdom and... | Daylight saving time | Wikipedia | 505 | 47548 | https://en.wikipedia.org/wiki/Daylight%20saving%20time | Technology | Timekeeping | null |
Willett's 1907 proposal illustrates several political issues. It attracted many supporters, including Arthur Balfour, Churchill, David Lloyd George, Ramsay MacDonald, King Edward VII (who used half-hour DST or "Sandringham time" at Sandringham), the managing director of Harrods, and the manager of the National Bank Ltd... | Daylight saving time | Wikipedia | 286 | 47548 | https://en.wikipedia.org/wiki/Daylight%20saving%20time | Technology | Timekeeping | null |
The end of World War I brought a change in DST use. Farmers continued to dislike DST, and many countries repealed it—like Germany itself, which dropped DST from 1919 to 1939 and from 1950 to 1979. Britain proved an exception; it retained DST nationwide but adjusted transition dates over the years for several reasons, i... | Daylight saving time | Wikipedia | 500 | 47548 | https://en.wikipedia.org/wiki/Daylight%20saving%20time | Technology | Timekeeping | null |
In 2003, the United Kingdom's Royal Society for the Prevention of Accidents supported a proposal to observe year-round daylight saving time, but it has been opposed by some industries, by some postal workers and farmers, and particularly by those living in the northern regions of the UK.
In 2005, the Sporting Goods Ma... | Daylight saving time | Wikipedia | 506 | 47548 | https://en.wikipedia.org/wiki/Daylight%20saving%20time | Technology | Timekeeping | null |
Religion
Some religious groups and individuals have opposed DST on religious grounds. For religious Muslims and Jews it makes religious practices such as prayer and fasting more difficult or inconvenient.
Some Muslim countries, such as Morocco, have temporarily abandoned DST during Ramadan.
In Israel, DST has been a ... | Daylight saving time | Wikipedia | 507 | 47548 | https://en.wikipedia.org/wiki/Daylight%20saving%20time | Technology | Timekeeping | null |
Effects on health
There are measurable adverse effects of clock-shifts on human health. It has been shown to disrupt human circadian rhythms, negatively affecting human health in the process, and that the yearly DST clock-shifts can increase health risks such as heart attacks and traffic accidents.
A 2017 study in th... | Daylight saving time | Wikipedia | 441 | 47548 | https://en.wikipedia.org/wiki/Daylight%20saving%20time | Technology | Timekeeping | null |
In 2022, a publication of three replicating studies of individuals, between individuals, and transecting societies, demonstrated that sleep loss affects the human motivation to help others, which in its fMRI findings is "associated with deactivation of key nodes within the social cognition brain network that facilitate... | Daylight saving time | Wikipedia | 487 | 47548 | https://en.wikipedia.org/wiki/Daylight%20saving%20time | Technology | Timekeeping | null |
Terminology
As explained by Richard Meade in the English Journal of the (American) National Council of Teachers of English, the form daylight savings time (with an "s") was already much more common than the older form daylight saving time in American English ("the change has been virtually accomplished") in 1978. Never... | Daylight saving time | Wikipedia | 444 | 47548 | https://en.wikipedia.org/wiki/Daylight%20saving%20time | Technology | Timekeeping | null |
The name of local time typically changes when DST is observed. American English replaces standard with daylight: for example, Pacific Standard Time (PST) becomes Pacific Daylight Time (PDT). In the United Kingdom, the standard term for UK time when advanced by one hour is British Summer Time (BST), and British English ... | Daylight saving time | Wikipedia | 308 | 47548 | https://en.wikipedia.org/wiki/Daylight%20saving%20time | Technology | Timekeeping | null |
IANA time zone database
The tz database maps a name to the named location's historical and predicted clock shifts. This database is used by many computer software systems, including most Unix-like operating systems, Java, and the Oracle RDBMS; HP's "tztab" database is similar but incompatible. When temporal authorities... | Daylight saving time | Wikipedia | 470 | 47548 | https://en.wikipedia.org/wiki/Daylight%20saving%20time | Technology | Timekeeping | null |
The United Kingdom and Ireland put clocks forward by an extra hour during World War II and experimented with year-round summer time between 1968 and 1971. Russia switched to permanent DST from 2011 to 2014, but the move proved unpopular because of the extremely late winter sunrises; in 2014, Russia switched permanently... | Daylight saving time | Wikipedia | 504 | 47548 | https://en.wikipedia.org/wiki/Daylight%20saving%20time | Technology | Timekeeping | null |
Some experts in circadian rhythms and sleep health recommend year-round standard time as the preferred option for public health and safety. However, some experts state that permanent daylight saving time is still a better option when compared to annual clock changes. Several chronobiology societies have published posi... | Daylight saving time | Wikipedia | 412 | 47548 | https://en.wikipedia.org/wiki/Daylight%20saving%20time | Technology | Timekeeping | null |
A low Earth orbit (LEO) is an orbit around Earth with a period of 128 minutes or less (making at least 11.25 orbits per day) and an eccentricity less than 0.25. Most of the artificial objects in outer space are in LEO, peaking in number at an altitude around , while the farthest in LEO, before medium Earth orbit (MEO),... | Low Earth orbit | Wikipedia | 478 | 47568 | https://en.wikipedia.org/wiki/Low%20Earth%20orbit | Physical sciences | Orbital mechanics | null |
Orbital characteristics
The mean orbital velocity needed to maintain a stable low Earth orbit is about , which translates to . However, this depends on the exact altitude of the orbit. Calculated for a circular orbit of the orbital velocity is , but for a higher orbit the velocity is reduced to . The launch vehicle's... | Low Earth orbit | Wikipedia | 483 | 47568 | https://en.wikipedia.org/wiki/Low%20Earth%20orbit | Physical sciences | Orbital mechanics | null |
A low Earth orbit requires the lowest amount of energy for satellite placement. It provides high bandwidth and low communication latency. Satellites and space stations in LEO are more accessible for crew and servicing.
Since it requires less energy to place a satellite into a LEO, and a satellite there needs less powe... | Low Earth orbit | Wikipedia | 492 | 47568 | https://en.wikipedia.org/wiki/Low%20Earth%20orbit | Physical sciences | Orbital mechanics | null |
In fiction
In the film 2001: A Space Odyssey, Earth's transit station ("Space Station V") "orbited 300 km above Earth".
Space debris
The LEO environment is becoming congested with space debris because of the frequency of object launches. This has caused growing concern in recent years, since collisions at orbital v... | Low Earth orbit | Wikipedia | 158 | 47568 | https://en.wikipedia.org/wiki/Low%20Earth%20orbit | Physical sciences | Orbital mechanics | null |
The American pickerel (Esox americanus) is a medium-sized species of North American freshwater predatory fish belonging to the pike family. The genus Esox is placed in family Esocidae in order Esociformes).
Two subspecies are sometimes recognised:
Redfin pickerel, sometimes called the brook pickerel, E. americanus a... | American pickerel | Wikipedia | 419 | 47571 | https://en.wikipedia.org/wiki/American%20pickerel | Biology and health sciences | Esociformes | Animals |
Both subspecies are native to the freshwater bodies of North America, and are not to be confused with their more aggressive big cousin, the northern pike. The redfin pickerel's range extends from the Saint Lawrence basin in Quebec down to the Gulf Coast, from Mississippi to Florida; while the grass pickerel's range is ... | American pickerel | Wikipedia | 164 | 47571 | https://en.wikipedia.org/wiki/American%20pickerel | Biology and health sciences | Esociformes | Animals |
The muskellunge (Esox masquinongy), often shortened to muskie, musky, ski, or lunge, is a species of large freshwater predatory fish native to North America. It is the largest member of the pike family, Esocidae.
Origin of name
The name "muskellunge" originates from the Ojibwe words maashkinoozhe meaning "great fish",... | Muskellunge | Wikipedia | 234 | 47578 | https://en.wikipedia.org/wiki/Muskellunge | Biology and health sciences | Esociformes | Animals |
Muskellunge closely resemble other esocids such as the northern pike (Esox lucius) and American pickerel (E. americanus) in both appearance and behavior. Like the northern pike and other aggressive pikes, the body plan is typical of ambush predators with an elongated body, flat head, and dorsal, pelvic, and anal fins s... | Muskellunge | Wikipedia | 344 | 47578 | https://en.wikipedia.org/wiki/Muskellunge | Biology and health sciences | Esociformes | Animals |
Habitat
Muskellunge are found in oligotrophic and mesotrophic lakes and large rivers from northern Michigan, northern Wisconsin, and northern Minnesota through the Great Lakes region, Chautauqua Lake in western New York, north into Canada, throughout most of the St Lawrence River drainage, and northward throughout the ... | Muskellunge | Wikipedia | 482 | 47578 | https://en.wikipedia.org/wiki/Muskellunge | Biology and health sciences | Esociformes | Animals |
According to the International Game Fish Association (IGFA) the largest muskellunge on record was caught by Cal Johnson in Lac Courte Oreilles (recognized as Lake Courte Oreilles by the association), Hayward, Wisconsin, United States, on July 24, 1949. The fish weighed and was in length, and in girth.
Behavior
Mus... | Muskellunge | Wikipedia | 439 | 47578 | https://en.wikipedia.org/wiki/Muskellunge | Biology and health sciences | Esociformes | Animals |
Subspecies and hybrids
Though interbreeding with other pike species can complicate the classification of some individuals, zoologists usually recognize up to three subspecies of muskellunge.
The Great Lakes Muskellunge or Spotted Muskellunge (E. m. masquinongy) is the most common variety in the Great Lakes basin and s... | Muskellunge | Wikipedia | 284 | 47578 | https://en.wikipedia.org/wiki/Muskellunge | Biology and health sciences | Esociformes | Animals |
Pollock or pollack (pronounced ) is the common name used for either of the two species of North Atlantic marine fish in the genus Pollachius. Pollachius pollachius is referred to as "pollock" in North America, Ireland and the United Kingdom, while Pollachius virens is usually known as saithe or coley in Great Britain a... | Pollock | Wikipedia | 412 | 47579 | https://en.wikipedia.org/wiki/Pollock | Biology and health sciences | Acanthomorpha | Animals |
Because of its slightly grey colour, pollock is often prepared, as in Norway, as fried fish balls, or if juvenile-sized, breaded with oatmeal and fried, as in Shetland. Year-old fish are traditionally split, salted, and dried over a peat hearth in Orkney, where their texture becomes wooden. Coalfish can also be salted ... | Pollock | Wikipedia | 290 | 47579 | https://en.wikipedia.org/wiki/Pollock | Biology and health sciences | Acanthomorpha | Animals |
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