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Suckling pig, a piglet slaughtered for its tender meat
Feeder pig, a weaned gilt or barrow weighing between and at 6 to 8 weeks of age that is sold to be finished for slaughter
Porker, market pig between and about dressed weight
Baconer, a market pig between and dressed weight. The maximum weight can vary between processors.
Grower, a pig between weaning and sale or transfer to the breeding herd, sold for slaughter or killed for rations.
Finisher, a grower pig over liveweight
Butcher hog, a pig of approximately , ready for the market. In some markets (Italy) the final weight of butcher pig is in the range. They tend to have hind legs suitable to produce cured ham
Backfatter, cull breeding pig sold for meat; usually refers specifically to a cull sow, but is sometimes used in reference to boars
Groups
Herd, a group of pigs, or all the pigs on a farm or in a region
Sounder, a small group of pigs (or wild boar) foraging in woodland
Pig parts
Trotters, the hooves of pigs (they have four hoofed toes on each foot, walking mainly on the larger central two)
Biology
In pig, pregnant
Farrowing, giving birth
Hogging, a sow when on heat (during estrus)
Housing
Sty, a small pig-house, usually with an outdoor run or a pig confinement
Pig-shed, a larger pig-house
Ark, a low semi circular field-shelter for pigs
Curtain-barn, a long, open building with curtains on the long sides of the barn. This increases ventilation on hot, humid summer days
Environmental and health impacts | Pig farming | Wikipedia | 339 | 15929223 | https://en.wikipedia.org/wiki/Pig%20farming | Technology | Animal husbandry | null |
Feces and waste often spread to surrounding neighborhoods, polluting air and water with toxic waste particles. Waste from swine on these farms carry a host of pathogens and bacteria as well as heavy metals. These toxins can leach down through the soil into groundwater, polluting local drinking water supplies. Pathogens can also become airborne, polluting the air and harming individuals when ingested. Contents from waste have been shown to cause detrimental health implications, as well as harmful algal blooms in surrounding bodies of water. Due to Concentrated Animal Feed Operations (CAFOs), those who live in the surrounding areas of pig farms tend to experience health complications. Symptoms included headaches, nausea, and weakness due to the fumes that are emitted from these farms. Those who work directly inside these farms often experience these symptoms more intensely. Typically, workers of these farms experience respiratory issues such as wheezing, coughing, and tightness of the chest as well as eye and nasal irritation. This is in part due to the air quality being poor because of the air particles being contaminated with hog feces.
Little to no regulation has been written by the EPA and federal legislators surrounding CAFOs to protect the welfare of both the environment and humans from their impacts. The only permit required by federal law on wastewater runoff by CAFOs is the National Pollutant Discharge Elimination System (NPDES) permit. NPDES are authorized under the Clean Water Act and aim to reduce dumping of pollutants in water systems. However, one of the most detrimental waste management practices used at swine farms, manure lagoons, have little to no regulations surrounding waste management, as they are not connected to a moving water source and therefore is not seen as an imminent threat to human or environmental health.
Occupational hazards
Common occupational hazards faced by pig farmers include but are not limited to exposure to toxic gases and particulate matter. The Occupational Safety and Health Administration or OSHA sets health and safety standards for hazardous substances in the workplace called permissible exposure limits or PELs. Specific PELs exist for toxic gases and particulate matter and these standards are legally enforced by OSHA to ensure that the safety and health of workers are protected.
Toxic Gas and Particulate Matter Exposure | Pig farming | Wikipedia | 447 | 15929223 | https://en.wikipedia.org/wiki/Pig%20farming | Technology | Animal husbandry | null |
Toxic gases including hydrogen sulfide, ammonia, methane and carbon dioxide are produced as a result of the decomposition of pig feces and these gases become highly concentrated in enclosed spaces of pig barns which can be hazardous to health when inhaled. Carbon monoxide is another commonly associated toxic gas that can accumulate in pig barns as a result of the trapping of combustion byproducts such as malfunctioning furnaces or gas heat sources in the absence of adequate ventilation.
Hydrogen sulfide gas has a foul, "rotten eggs" smell at low concentrations but paralyzes the olfactory nerve at higher concentrations so that no smell is sensed. Exposure to high levels, well beyond the OSHA PEL, of hydrogen sulfide can cause fatal respiratory paralysis. The common source of hydrogen sulfide are covered manure pits below the pig barns that act as feces reservoirs. These manure pits require regular emptying and during this process, high levels of hydrogen sulfide is released and seeps into pig barns. Pig barns must be void of any human or animal inhabitants during this emptying process and require a several hour "waiting period" until occupants can safely reenter the barn.
Ammonia gas has a strong odor that can be smelled at low levels, below the OSA PEL, but does not have any negative health effects. At higher levels, ammonia is irritating to the body's mucous membranes such as the eyes, nose, mouth, throat and lungs. Particulate matter in pig barns often absorbs ammonia as it floats through the air. These particles are then inhaled and increase the irritating effect of ammonia.
Methane and carbon dioxide are combustible gases meaning that they can burn, catch fire or explode easily. They are also known as chemical asphyxiants and at high levels can cause suffocation by displacing oxygen from the air.
Particulate matter is produced when small fragments of pig hair or skin, dried feces, or feed can detach and become suspended in the air in pig barns. The increased concentration of particulate matter in the air, especially in confined spaces, can lead to respiratory tract irritation and other health effects when inhaled. Bacteria and viruses, such as influenza, can travel through the air on particulate matter and increase the risk of transmission of disease. | Pig farming | Wikipedia | 460 | 15929223 | https://en.wikipedia.org/wiki/Pig%20farming | Technology | Animal husbandry | null |
OSHA requires that toxic gas and particulate matter be measured at least twice yearly preferably in the autumn months and again in the winter when natural ventilation is the most reduced. Workers are also advised to wear N-95 respirators and eye protection when inside of pig barns to prevent the inhalation of toxic gases and particulate matter as well as irritation to the of eyes.
Geopolitical issues
As with other commodities, pork presents challenges in the politics of international trade as national interests compete and seek economic modus vivendi. Changes to policy can upset the existing balances, prompting economic anxiety. For example, in 2020, the hog farming sector in Taiwan was upset by a decision to allow imports from the United States without labeling of ractopamine use. Farmers' views varied on how negative the effects might be. Issues of pride and degree of autarky also figure into such debates; people understandably wonder whether trade competition changes will deeply damage domestic production capability, while accurate quantitative answers are often difficult to find amid the mass of debate.
Drugs
Growth promoters
Ractopamine
Most pigs in the US receive ractopamine which promotes muscle instead of fat, quicker weight gain, and reduced costs and pollutants in the environment. Such pigs consume less feed to reach finishing weight and produce less manure. Ractopamine has not been approved for use by the European Union, China, Russia, and several other countries.
Colistin
China once used colistin (an antibiotic) as growth promoter (subtherapeutic antibiotic use) but discovered a colistin-resistant form of E. coli bacteria in a pig from a Shanghai farm in 2013. Investigations then led to the identification of "a gene called MCR-1 that allowed bacteria to survive colistin treatment in animals and humans." In 2016, these findings led China to ban colistin as growth promoter.
Antibiotics
A systematic review found that penicillins and tetracyclines were the most commonly used antibiotics in pigs. | Pig farming | Wikipedia | 412 | 15929223 | https://en.wikipedia.org/wiki/Pig%20farming | Technology | Animal husbandry | null |
Parasites
Toxoplasmosis is a constant pressure on pig farming. Worldwide, the percentage of pigs harboring viable Toxoplasma gondii parasites has been measured to be 3% to 71.43%. Surveys of seroprevalence (T. gondii antibodies in blood) are more common, and such measurements are indicative of the high relative seroprevalence in pigs across the world. Neonatal piglets have been found to suffer the entire range of severity, including progression to stillbirth. This was especially demonstrated in the foundational Thiptara et al. 2006, reporting a litter birth of three stillborns and six live in Thailand. This observation has been relevant not only to that country but to toxoplasmosis control in porciculture around the world.
Hygiene
Excessively hygienic raising conditions were found to prevent proper gut microbiota development by Schmidt et al. 2011. Moore et al. 1995 describes the pathology of Cryptosporidium infection, a common difficulty in piglet production.
In an attempt to curb diseases such as African swine fever, a number of Chinese companies have built condominium-style mega complexes multiple stories high to house thousands of pigs. The buildings have been dubbed "hog hotels" and come with strict protocols and advanced cleaning, veterinary, and disposal systems. However, doubt has been raised by policy specialists and animal scientists over the facilities' efficacy in preventing outbreaks. The welfare of the animals has also been a source of concern, and it has been suggested that the poor welfare of the pigs may cause a decline in their immunity. | Pig farming | Wikipedia | 331 | 15929223 | https://en.wikipedia.org/wiki/Pig%20farming | Technology | Animal husbandry | null |
Parasitoid wasps are a large group of hymenopteran superfamilies, with all but the wood wasps (Orussoidea) being in the wasp-waisted Apocrita. As parasitoids, they lay their eggs on or in the bodies of other arthropods, sooner or later causing the death of these hosts. Different species specialise in hosts from different insect orders, most often Lepidoptera, though some select beetles, flies, or bugs; the spider wasps (Pompilidae) exclusively attack spiders.
Parasitoid wasp species differ in which host life-stage they attack: eggs, larvae, pupae, or adults. They mainly follow one of two major strategies within parasitism: either they are endoparasitic, developing inside the host, and koinobiont, allowing the host to continue to feed, develop, and moult; or they are ectoparasitic, developing outside the host, and idiobiont, paralysing the host immediately. Some endoparasitic wasps of the superfamily Ichneumonoidea have a mutualistic relationship with polydnaviruses, the viruses suppressing the host's immune defenses.
Parasitoidism evolved only once in the Hymenoptera, during the Permian, leading to a single clade called Euhymenoptera, but the parasitic lifestyle has secondarily been lost several times including among the ants, bees, and vespid wasps. As a result, the order Hymenoptera contains many families of parasitoids, intermixed with non-parasitoid groups. The parasitoid wasps include some very large groups, some estimates giving the Chalcidoidea as many as 500,000 species, the Ichneumonidae 100,000 species, and the Braconidae up to 50,000 species.
Host insects have evolved a range of defences against parasitoid wasps, including hiding, wriggling, and camouflage markings.
Many parasitoid wasps are considered beneficial to humans because they naturally control agricultural pests. Some are applied commercially in biological pest control, starting in the 1920s with Encarsia formosa to control whitefly in greenhouses. Historically, parasitoidism in wasps influenced the thinking of Charles Darwin.
Parasitoidism | Parasitoid wasp | Wikipedia | 474 | 5457188 | https://en.wikipedia.org/wiki/Parasitoid%20wasp | Biology and health sciences | Hymenoptera | Animals |
Parasitoid wasps range from some of the smallest species of insects to wasps about an inch long. Most females have a long, sharp ovipositor at the tip of the abdomen, sometimes lacking venom glands, and almost never modified into a sting.
Parasitoids can be classified in a variety of ways. They can live within their host's body as endoparasitoids, or feed on it from outside as ectoparasitoids: both strategies are found among the wasps. Parasitoids can also be divided according to their effect on their hosts. Idiobionts prevent further development of the host after initially immobilizing it, while koinobionts allow the host to continue its development while they are feeding upon it; and again, both types are seen in parasitoidal wasps. Most ectoparasitoid wasps are idiobiont, as the host could damage or dislodge the external parasitoid if allowed to move or moult. Most endoparasitoid wasps are koinobionts, giving them the advantage of a host that continues to grow larger and remains able to avoid predators.
Hosts
Many parasitoid wasps use larval Lepidoptera as hosts, but some groups parasitize different host life stages (egg, larva or nymph, pupa, adult) of nearly all other orders of insects, especially Coleoptera, Diptera, Hemiptera and other Hymenoptera. Some attack arthropods other than insects: for instance, the Pompilidae specialise in catching spiders: these are quick and dangerous prey, often as large as the wasp itself, but the spider wasp is quicker, swiftly stinging her prey to immobilise it. Adult female wasps of most species oviposit into their hosts' bodies or eggs.
More rarely, parasitoid wasps may use plant seeds as hosts, such as Torymus druparum.
Some also inject a mix of secretory products that paralyse the host or protect the egg from the host's immune system; these include polydnaviruses, ovarian proteins, and venom. If a polydnavirus is included, it infects the nuclei of host hemocytes and other cells, causing symptoms that benefit the parasite. | Parasitoid wasp | Wikipedia | 470 | 5457188 | https://en.wikipedia.org/wiki/Parasitoid%20wasp | Biology and health sciences | Hymenoptera | Animals |
Host size is important for the development of the parasitoid, as the host is its entire food supply until it emerges as an adult; small hosts often produce smaller parasitoids. Some species preferentially lay female eggs in larger hosts and male eggs in smaller hosts, as the reproductive capabilities of males are limited less severely by smaller adult body size.
Some parasitoid wasps mark the host with chemical signals to show that an egg has been laid there. This may both deter rivals from ovipositing, and signal to itself that no further egg is needed in that host, effectively reducing the chances that offspring will have to compete for food and increasing the offspring's survival.
Life cycle
On or inside the host the parasitoid egg hatches into a larva or two or more larvae (polyembryony). Endoparasitoid eggs can absorb fluids from the host body and grow several times in size from when they were first laid before hatching. The first instar larvae are often highly mobile and may have strong mandibles or other structures to compete with other parasitoid larvae. The following instars are generally more grub-like. Parasitoid larvae have incomplete digestive systems with no rear opening. This prevents the hosts from being contaminated by their wastes. The larva feeds on the host's tissues until ready to pupate; by then the host is generally either dead or almost so. A meconium, or the accumulated wastes from the larva is cast out as the larva transitions to a prepupa. Depending on its species, the parasitoid then may eat its way out of the host or remain in the more or less empty skin. In either case it then generally spins a cocoon and pupates. As adults, parasitoid wasps feed primarily on nectar from flowers. Females of some species will also drink hemolymph from hosts to gain additional nutrients for egg production.
Mutualism with polydnavirus | Parasitoid wasp | Wikipedia | 403 | 5457188 | https://en.wikipedia.org/wiki/Parasitoid%20wasp | Biology and health sciences | Hymenoptera | Animals |
Polydnaviruses are a unique group of insect viruses that have a mutualistic relationship with some parasitic wasps. The polydnavirus replicates in the oviducts of an adult female parasitoid wasp. The wasp benefits from this relationship because the virus provides protection for the parasitic larvae inside the host, (i) by weakening the host's immune system and (ii) by altering the host's cells to be more beneficial to the parasite. The relationship between these viruses and the wasp is obligatory in the sense that all individuals are infected with the viruses; the virus has been incorporated in the wasp's genome and is inherited.
Host defenses
The hosts of parasitoids have developed several levels of defence. Many hosts try to hide from the parasitoids in inaccessible habitats. They may also get rid of their frass (body wastes) and avoid plants that they have chewed on as both can signal their presence to parasitoids hunting for hosts. The egg shells and cuticles of the potential hosts are thickened to prevent the parasitoid from penetrating them. Hosts may use behavioral evasion when they encounter an egg laying female parasitoid, like dropping off the plant they are on, twisting and thrashing so as to dislodge or kill the female and even regurgitating onto the wasp to entangle it. The wriggling can sometimes help by causing the wasp to "miss" laying the egg on the host and instead place it nearby. Wriggling of pupae can cause the wasp to lose its grip on the smooth hard pupa or get trapped in the silk strands. Some caterpillars even bite the female wasps that approach them. Some insects secrete poisonous compounds that kill or drive away the parasitoid. Ants that are in a symbiotic relationship with caterpillars, aphids or scale insects may protect them from attack by wasps.
Parasitoid wasps are vulnerable to hyperparasitoid wasps. Some parasitoid wasps change the behavior of the infected host, causing them to build a silk web around the pupae of the wasps after they emerge from its body to protect them from hyperparasitoids. | Parasitoid wasp | Wikipedia | 441 | 5457188 | https://en.wikipedia.org/wiki/Parasitoid%20wasp | Biology and health sciences | Hymenoptera | Animals |
Hosts can kill endoparasitoids by sticking haemocytes to the egg or larva in a process called encapsulation. In aphids, the presence of a particular species of γ-3 Pseudomonadota makes the aphid relatively immune to their parasitoid wasps by killing many of the eggs. As the parasitoid's survival depends on its ability to evade the host's immune response, some parasitoid wasps have developed the counterstrategy of laying more eggs in aphids that have the endosymbiont, so that at least one of them may hatch and parasitize the aphid.
Certain caterpillars eat plants that are toxic to both themselves and the parasite to cure themselves. Drosophila melanogaster larvae also self-medicate with ethanol to treat parasitism. D. melanogaster females lay their eggs in food containing toxic amounts of alcohol if they detect parasitoid wasps nearby. The alcohol protects them from the wasps, at the cost of retarding their own growth.
Evolution and taxonomy
Evolution | Parasitoid wasp | Wikipedia | 223 | 5457188 | https://en.wikipedia.org/wiki/Parasitoid%20wasp | Biology and health sciences | Hymenoptera | Animals |
Based on genetic and fossil analysis, parasitoidism has evolved only once in the Hymenoptera, during the Permian, leading to a single clade. All parasitoid wasps are descended from this lineage. The narrow-waisted Apocrita emerged during the Jurassic. The Aculeata, which includes bees, ants, and parasitoid spider wasps, evolved from within the Apocrita; it contains many families of parasitoids, though not the Ichneumonoidea, Cynipoidea, and Chalcidoidea. The Hymenoptera, Apocrita, and Aculeata are all clades, but since each of these contains non-parasitic species, the parasitoid wasps, formerly known as the Parasitica, do not form a clade on their own. The common ancestor in which parasitoidism evolved lived approximately 247 million years ago and was previously believed to be an ectoparasitoid wood wasp that fed on wood-boring beetle larvae. Species similar in lifestyle and morphology to this ancestor still exist in the Ichneumonoidea. However, recent molecular and morphological analysis suggests this ancestor was endophagous, meaning it fed from within its host. A significant radiation of species in the Hymenoptera occurred shortly after the evolution of parasitoidy in the order and is thought to have been a result of it. The evolution of a wasp waist, a constriction in the abdomen of the Apocrita, contributed to rapid diversification as it increased maneuverability of the ovipositor, the organ off the rear segment of the abdomen used to lay eggs.
The phylogenetic tree gives a condensed overview of the positions of parasitoidal groups (boldface), amongst groups (italics) like the Vespidae which have secondarily abandoned the parasitoid habit. The approximate numbers of species estimated to be in these groups, often much larger than the number so far described, is shown in parentheses, with estimates for the most populous also shown in boldface, like "(150,000)". Not all species in these groups are parasitoidal: for example, some Cynipoidea are phytophagous.
Taxonomy | Parasitoid wasp | Wikipedia | 462 | 5457188 | https://en.wikipedia.org/wiki/Parasitoid%20wasp | Biology and health sciences | Hymenoptera | Animals |
The parasitoid wasps are paraphyletic since the ants, bees, and non-parasitic wasps such as the Vespidae are not included, and there are many members of mainly parasitoidal families which are not themselves parasitic. Listed are Hymenopteran families where most members have a parasitoid lifestyle.
Symphyta:
Orussidae
Apocrita:
Scolebythidae
Bethylidae
Chrysididae
Sclerogibbidae
Dryinidae
Embolemidae
Tiphiidae
Thynnidae
Sapygidae
Mutillidae
Bradynobaenidae
Chyphotidae
Sierolomorphidae
Braconidae
Ichneumonidae
Pompilidae
Rhopalosomatidae
Aulacidae
Evaniidae
Gasteruptiidae
Stephanidae
Megalyridae
Trigonalidae
Ibaliidae
Liopteridae
Figitidae
Austroniidae
Diapriidae
Heloridae
Monomachidae
Pelecinidae
Peradeniidae
Proctotrupidae
Roproniidae
Vanhorniidae
Platygastridae
Scelionidae
Megaspilidae
Ceraphronidae
Mymarommatidae
Chalcidoidea (19 families)
Ampulicidae
Interactions with humans
Biological pest control
Parasitoid wasps are considered beneficial as they naturally control the population of many pest insects. They are widely used commercially (alongside other parasitoids such as tachinid flies) for biological pest control, for which the most important groups are the ichneumonid wasps, which prey mainly on caterpillars of butterflies and moths; braconid wasps, which attack caterpillars and a wide range of other insects including greenfly; chalcidoid wasps, which parasitise eggs and larvae of greenfly, whitefly, cabbage caterpillars, and scale insects.
One of the first parasitoid wasps to enter commercial use was Encarsia formosa, an endoparasitic aphelinid. It has been used to control whitefly in greenhouses since the 1920s. Use of the insect fell almost to nothing, replaced by chemical pesticides by the 1940s. Since the 1970s, usage has revived, with renewed usage in Europe and Russia. In some countries, such as New Zealand, it is the primary biological control agent used to control greenhouse whiteflies, particularly on crops such as tomato, a particularly difficult plant for predators to establish on. | Parasitoid wasp | Wikipedia | 492 | 5457188 | https://en.wikipedia.org/wiki/Parasitoid%20wasp | Biology and health sciences | Hymenoptera | Animals |
Commercially, there are two types of rearing systems: short-term seasonal daily output with high production of parasitoids per day, and long-term year-round low daily output with a range in production of 4–1000 million female parasitoids per week, to meet demand for suitable parasitoids for different crops.
In culture
Parasitoid wasps influenced the thinking of Charles Darwin. In an 1860 letter to the American naturalist Asa Gray, Darwin wrote: "I cannot persuade myself that a beneficent and omnipotent God would have designedly created parasitic wasps with the express intention of their feeding within the living bodies of Caterpillars." The palaeontologist Donald Prothero notes that religiously-minded people of the Victorian era, including Darwin, were horrified by this instance of evident cruelty in nature, particularly noticeable in the Ichneumonidae. | Parasitoid wasp | Wikipedia | 180 | 5457188 | https://en.wikipedia.org/wiki/Parasitoid%20wasp | Biology and health sciences | Hymenoptera | Animals |
Harvester ant is a common name for any of the species or genera of ants that collect seeds (called seed predation), or mushrooms as in the case of Euprenolepis procera, which are stored in the nest in communal chambers called granaries. They are also referred to as agricultural ants. Seed harvesting by some desert ants is an adaptation to the lack of typical ant resources such as prey or honeydew from hemipterans. Harvester ants increase seed dispersal and protection, and provide nutrients that increase seedling survival of the desert plants. In addition, ants provide soil aeration through the creation of galleries and chambers, mix deep and upper layers of soil, and incorporate organic refuse into the soil.
Seed dispersal
Ants may play an important role in the dynamics of plant communities by acting either as seed dispersal agents or as seed predators, or both. During the day, these ants search the savannas for vegetation and plant seeds, and carry them along back to their nest. The two main mechanisms through which ants disperse seeds are myrmecochory, or seed dispersal mediated by the elaiosome, i.e., a lipid-rich seed appendage that mainly attracts non-granivorous ants and provides rewards for seed dispersal, and diszoochory, or seed dispersal performed by seed-harvesting ants that is not mediated by any particular seed structure. While the former has traditionally been recognized mainly as a mutualism, the latter is usually perceived as an antagonism.
Foraging behavior
Harvester ants foraging in hot, dry conditions lose water, but obtain water from metabolizing fats in the seeds they eat. Positive feedback on foraging activity, from returning foragers with food, allows the colony to regulate its foraging activity according to the current costs of desiccation and the benefits based on current food availability.
In many harvester ant species, foraging behavior is influenced by the weather. For example, in the ant Messor andrei, recruitment to food bait is higher in more humid conditions. Both humidity and food availability are affected by day-to-day changes in weather conditions. Food is distributed by wind and flooding and rain uncover seeds in the top layer of the soil. In Pogonomyrmex barbatus, daily changes in conditions such as humidity and food availability produce strong daily trends in the foraging activity of all colonies. | Harvester ant | Wikipedia | 481 | 2155942 | https://en.wikipedia.org/wiki/Harvester%20ant | Biology and health sciences | Hymenoptera | Animals |
Colonies may vary in the relation between humidity and foraging activity. Colonies differ consistently from year to year in how often they forage at all and most colonies forage on days with high humidity and high food availability, such as those just after a rain when flooding has exposed a layer of seeds in the soil. Few colonies forage on very dry days. Colonies also differ in how likely they are to adjust the rate of outgoing foragers to the rate of forager return. While all colonies tend to adjust outgoing foraging rate closely when conditions are good, only some colonies do so in poor conditions.
Sting
Harvester ants, for their size, have a rather potent venom. They inject it into their victim via sting by biting down and following up with a rapid sting from their abdomen. This causes 4-8 hours of sharp pain with effects similar to neurotoxicity such as piloerection and localized swelling around the area of the sting.
Species and genera
Aphaenogaster - about 200 species
Novomessor, seed harvesters
Novomessor cockerelli
Euprenolepis - eight species
Euprenolepis procera, nomadic mushroom-harvesters, a previously unknown lifestyle among ants
Messor, seed-harvesters
Pheidole, seed-harvesters
Pogonomyrmex, seed-harvesters
Pogonomyrmex barbatus
Pogonomyrmex maricopa, a venomous species found in Arizona, USA
Pogonomyrmex occidentalis, seed-harvesters
Carebara
Carebara diversa, seed harvesters | Harvester ant | Wikipedia | 320 | 2155942 | https://en.wikipedia.org/wiki/Harvester%20ant | Biology and health sciences | Hymenoptera | Animals |
The Australorp is an Australian breed of dual-purpose utility chicken. It derives from the British Black Orpington, and was selectively bred for egg-laying performance; some hens lay more than 300 eggs per year. It achieved world-wide popularity in the 1920s after the breed broke numerous world records for number of eggs laid and has been a popular breed in the western world since. It is one of eight poultry breeds created in Australia and recognised by the Australian Poultry Standards. The original plumage colour is black, which is the only colour recognised in the United States of America, but blue and white are also recognised in Australia and the Poultry Club South Africa recognises buff, splash, wheaten laced and golden in addition.
History
The original stock used in the development of the Australorp was imported to Australia from England out of the Black Orpington yards of William Cook and Joseph Partington in the period from 1890 to the early 1900s with Rhode Island Red. Local breeders used this stock together with judicious out-crossings of Minorca, White Leghorn and Langshan blood to improve the utility features of the imported Orpingtons. There is even a report of some Plymouth Rock blood also being used. The emphasis of the early breeders was on utility features. At this time, the resulting birds were known as Australian Black Orpingtons (Austral-orp). | Australorp | Wikipedia | 283 | 2156142 | https://en.wikipedia.org/wiki/Australorp | Biology and health sciences | Chickens | Animals |
The origin of the name "Australorp" seems to be shrouded in as much controversy as the attempts to obtain agreement between the States over a suitable national Standard. The earliest claim to the name was made by one of poultry fancy's institutions, Wiliam Wallace Scott, before the First World War. From 1925 Wal Scott set to work to have Australorp recognised as a breed with the Poultry Society as he developed the breed. Equally as persuasive a claim came in 1919 from Arthur Harwood who suggested that the "Australian Laying Orpingtons" be named "Australs". The letters "orp" were suggested as a suffix to denote the major breed in the fowl's development. A further overseas claim to the name came from Britain's W. Powell-Owen who drafted the British Standard for the breed in 1921 following the importation of the "Australian Utility Black Orpingtons". It is certain that the name "Australorp" was being used in the early 1920s when the breed was launched internationally. The Australorp was added to the Standard of Perfection of the American Poultry Association in 1929.
A white colour variety was bred in South Africa the 1930s, and in Australia in the 1940s. It was recognised in Australia in 2012. A bantam Australorp was bred in the early 1930s by Roy Corner and Jack Mann, and was first exhibited at a poultry show in 1934.
The Australorp is reported in all five inhabited continents, in seventeen countries of which four report a population of or more: Australia, Serbia, Slovakia and the United States. In 2024 the world-wide population was estimated at close to , with an overall conservation status of "not at risk". The risk status in Australia was listed as "at/risk/endangered" in DAD-IS, while in the United Kingdom it was listed as "priority" on the watchlist of the Rare Breeds Survival Trust. In the United States it was removed from the watchlist of the Livestock Conservancy in 2023.
Characteristics
There are both bantam and standard-sized Australorps.
Three colours are recognised in the Australian Poultry Standards: black, white and blue; the same three colours are recognised by the Entente Européenne and by the Poultry Club of Great Britain. The Poultry Club South Africa recognises a further four colours: buff, splash, wheaten laced, and golden.
Use | Australorp | Wikipedia | 502 | 2156142 | https://en.wikipedia.org/wiki/Australorp | Biology and health sciences | Chickens | Animals |
The egg-laying performance of Australorps attracted attention when in 1922–1923, a team of six hens set a world record by laying 1857 eggs for an average of 309.5 eggs per hen during a 365 consecutive day trial. These figures were achieved without the lighting regimens of the modern intensive shed. Such performances had importation orders flooding in from England, United States of America, South Africa, Canada and Mexico. A new record was set when a hen laid 364 eggs in 365 days. They are also known to be good nest sitters and mothers, making them one of the most popular large heritage utility breeds of chicken.
Hens lay approximately 190 light brown eggs per year, with an average weight of ; bantam hens lay some 160 per year, averaging in weight. | Australorp | Wikipedia | 161 | 2156142 | https://en.wikipedia.org/wiki/Australorp | Biology and health sciences | Chickens | Animals |
Visual or vision impairment (VI or VIP) is the partial or total inability of visual perception. In the absence of treatment such as corrective eyewear, assistive devices, and medical treatment, visual impairment may cause the individual difficulties with normal daily tasks, including reading and walking. The terms low vision and blindness are often used for levels of impairment which are difficult or impossible to correct and significantly impact daily life. In addition to the various permanent conditions, fleeting temporary vision impairment, amaurosis fugax, may occur, and may indicate serious medical problems.
The most common causes of visual impairment globally are uncorrected refractive errors (43%), cataracts (33%), and glaucoma (2%). Refractive errors include near-sightedness, far-sightedness, presbyopia, and astigmatism. Cataracts are the most common cause of blindness. Other disorders that may cause visual problems include age-related macular degeneration, diabetic retinopathy, corneal clouding, childhood blindness, and a number of infections. Visual impairment can also be caused by problems in the brain due to stroke, premature birth, or trauma, among others. These cases are known as cortical visual impairment. Screening for vision problems in children may improve future vision and educational achievement. Screening adults without symptoms is of uncertain benefit. Diagnosis is by an eye exam.
The World Health Organization (WHO) estimates that 80% of visual impairment is either preventable or curable with treatment. This includes cataracts, the infections river blindness and trachoma, glaucoma, diabetic retinopathy, uncorrected refractive errors, and some cases of childhood blindness. Many people with significant visual impairment benefit from vision rehabilitation, changes in their environment, and assistive devices.
, there were 940 million people with some degree of vision loss. 246 million had low vision and 39 million were blind. The majority of people with poor vision are in the developing world and are over the age of 50 years. Rates of visual impairment have decreased since the 1990s. Visual impairments have considerable economic costs both directly due to the cost of treatment and indirectly due to decreased ability to work.
Classification | Visual impairment | Wikipedia | 459 | 2158298 | https://en.wikipedia.org/wiki/Visual%20impairment | Biology and health sciences | Disability | null |
In 2010, the WHO definition for visual impairment was changed and now follows the ICD-11. The previous definition which used "best corrected visual acuity" was changed to "presenting visual acuity". This change was made as newer studies showed that best-corrected vision overlooks a larger proportion of the population who has visual impairment due to uncorrected refractive errors, and/or lack of access to medical or surgical treatment.
Distance vision impairment:
Category 0: No or mild visual impairment – presenting visual acuity better than 6/18
Category 1: Moderate visual impairment – presenting visual acuity worse than 6/18 and better than 6/60
Category 2: Severe visual impairment – presenting visual acuity worse than 6/60 and better than 3/60
Category 3: Blindness – presenting visual acuity worse than 3/60 and better than 1/60
Category 4: Blindness – presenting visual acuity worse than 1/60 with light perception
Category 5: Blindness – irreversible blindness with no light perception
Near vision impairment:
Near visual acuity worse than N6 or M 0.8 at 40 cm.
United Kingdom
Severely sight impaired
Defined as having central visual acuity of less than 3/60 with normal fields of vision, or gross visual field restriction.
Unable to see at what the normally sighted person sees at .
Sight impaired
Able to see at , but not at , what the normally sighted person sees at
Less severe visual impairment is not captured by registration data, and its prevalence is difficult to quantify
Low vision
A visual acuity of less than 6/18 but greater than 3/60.
Not eligible to drive and may have difficulty recognising faces across a street, watching television, or choosing clean, unstained, co-ordinated clothing.
In the UK, the Certificate of Vision Impairment (CVI) is used to certify people as being severely sight impaired or sight impaired. The accompanying guidance for clinical staff states: "The National Assistance Act 1948 states that a person can be certified as severely sight impaired if they are 'so blind as to be unable to perform any work for which eye sight is essential'". Certification is based on whether a person can do any work for which eyesight is essential, not just one particular job (such as their job before becoming blind). | Visual impairment | Wikipedia | 470 | 2158298 | https://en.wikipedia.org/wiki/Visual%20impairment | Biology and health sciences | Disability | null |
In practice, the definition depends on individuals' visual acuity and the extent to which their field of vision is restricted. The Department of Health identifies three groups of people who may be classified as severely visually impaired.
Those below 3/60 (equivalent to 20/400 in US notation) Snellen (most people below 3/60 are severely sight impaired).
Those better than 3/60 but below 6/60 Snellen (people who have a very contracted field of vision only).
Those 6/60 Snellen or above (people in this group who have a contracted field of vision especially if the contraction is in the lower part of the field).
The Department of Health also state that a person is more likely to be classified as severely visually impaired if their eyesight has failed recently or if they are an older individual, both groups being perceived as less able to adapt to their vision loss.
United States
In the United States, any person with vision that cannot be corrected to better than 20/200 in the better eye, or who has 20 degrees (diameter) or less of visual field remaining, is considered legally blind or eligible for disability classification and possible inclusion in certain government sponsored programs.
The terms partially sighted, low vision, legally blind and totally blind are used by schools, colleges, and other educational institutions to describe students with visual impairments. They are defined as follows:
Partially sighted indicates some type of visual problem, with a need of person to receive special education in some cases.
Low vision generally refers to a severe visual impairment, not necessarily limited to distance vision. Low vision applies to all individuals with sight who are unable to read the newspaper at a normal viewing distance, even with the aid of eyeglasses or contact lenses. They use a combination of vision and other senses to learn, although they may require adaptations in lighting or the size of print, and, sometimes, braille.
Legally blind indicates that a person has less than 20/200 vision in the better eye after best correction (contact lenses or glasses), or a field of vision of less than 20 degrees in the better eye.
Totally blind students learn via braille or other non-visual media.
In 1934, the American Medical Association adopted the following definition of blindness:
The United States Congress included this definition as part of the Aid to the Blind program in the Social Security Act passed in 1935. In 1972, the Aid to the Blind program and two others combined under Title XVI of the Social Security Act to form the Supplemental Security Income program which states: | Visual impairment | Wikipedia | 510 | 2158298 | https://en.wikipedia.org/wiki/Visual%20impairment | Biology and health sciences | Disability | null |
Temporary vision impairment
Vision impairment for a few seconds, or minutes, may occur due to any of a variety of causes, some serious and requiring medical attention.
Health effects
General functioning
Visual impairments may take many forms and be of varying degrees. Visual acuity alone is not always a good predictor of an individual's function. Someone with relatively good acuity (e.g., 20/40) can have difficulty with daily functioning, while someone with worse acuity (e.g., 20/200) may function reasonably well if they have low visual demands.
Best-corrected visual acuity differs from presenting visual acuity; a person with a "normal" best corrected acuity can have "poor" presenting acuity (e.g. individual who has uncorrected refractive error). Thus, measuring an individual's general functioning depends on one's situational and contextual factors, as well as access to treatment.
The American Medical Association has estimated that the loss of one eye equals 25% impairment of the visual system and 24% impairment of the whole person; total loss of vision in both eyes is considered to be 100% visual impairment and 85% impairment of the whole person.
Some people who fall into this category can use their considerable residual vision – their remaining sight – to complete daily tasks without relying on alternative methods. The role of a low vision specialist (optometrist or ophthalmologist) is to maximize the functional level of a patient's vision by optical or non-optical means. Primarily, this is by use of magnification in the form of telescopic systems for distance vision and optical or electronic magnification for near tasks.
People with significantly reduced acuity may benefit from training conducted by individuals trained in the provision of technical aids. Low vision rehabilitation professionals, some of whom are connected to an agency for the blind, can provide advice on lighting and contrast to maximize remaining vision. These professionals also have access to non-visual aids, and can instruct patients in their uses.
Mobility
Older adults with visual impairment are at an increased risk of physical inactivity, slower gait speeds, and fear of falls. | Visual impairment | Wikipedia | 442 | 2158298 | https://en.wikipedia.org/wiki/Visual%20impairment | Biology and health sciences | Disability | null |
Physical activity is a useful predictor of overall well-being, and routine physical activity reduces the risk of developing chronic diseases and disability. Older adults with visual impairment (including glaucoma, age-related macular degeneration, and diabetic retinopathy) have decreased physical activity as measured with self-reports and accelerometers. The US National Health and Nutrition Examination Survey (NHANES) showed that people with corrected visual acuity of less than 20/40 spent significantly less time in moderate to vigorous physical activity. Age-related macular degeneration is also associated with a 50% decrease in physical activity–however physical activity is protective against age-related macular degeneration progression.
In terms of mobility, those with visual impairment have a slower gait speed than those without visual impairment; however, the rate of decline remains proportional with increasing age in both groups. Additionally, the visually impaired also have greater difficulty walking a quarter mile (400 m) and walking up stairs, as compared to those with normal vision.
Cognitive
Older adults with vision loss are at an increased risk of memory loss, cognitive impairment, and cognitive decline.
Social and psychological
Studies demonstrate an association between older adults with visual impairment and a poor mental health; discrimination was identified as one of the causes of this association. Older adults with visual impairment have a 1.5-fold risk of reporting perceived discrimination and of these individuals, there was a 2-fold risk of loneliness and 4-fold risk of reporting a lower quality of life. Among adults with visual impairment, the prevalence of moderate loneliness is 28.7% (18.2% in general population) and prevalence of severe loneliness is 19.7% (2.7% in general population). The risk of depression and anxiety are also increased in the visually impaired; 32.2% report depressive symptoms (12.01% in general population), and 15.61% report anxiety symptoms (10.69% in general population).
The subjects making the most use of rehabilitation instruments, who lived alone, and preserved their own mobility and occupation were the least depressed, with the lowest risk of suicide and the highest level of social integration. | Visual impairment | Wikipedia | 445 | 2158298 | https://en.wikipedia.org/wiki/Visual%20impairment | Biology and health sciences | Disability | null |
Those with worsening sight and the prognosis of eventual blindness are at comparatively high risk of suicide and thus may be in need of supportive services. Many studies have demonstrated how rapid acceptance of the serious visual impairment has led to a better, more productive compliance with rehabilitation programs. Moreover, psychological distress has been reported to be at its highest when sight loss is not complete, but the prognosis is unfavorable. Therefore, early intervention is imperative for enabling successful psychological adjustment.
Associated conditions
Blindness can occur in combination with such conditions as intellectual disability, autism spectrum disorders, cerebral palsy, hearing impairments, and epilepsy. Blindness in combination with hearing loss is known as deafblindness.
It has been estimated that over half of completely blind people have non-24-hour sleep–wake disorder, a condition in which a person's circadian rhythm, normally slightly longer than 24 hours, is not entrained (synchronized) to the lightdark cycle.
Cause
The most common causes of visual impairment globally in 2010 were:
Refractive error (42%)
Cataract (33%)
Glaucoma (2%)
Age-related macular degeneration (1%)
Corneal opacification (1%)
Diabetic retinopathy (1%)
Childhood blindness
Trachoma (1%)
Undetermined (18%)
The most common causes of blindness worldwide in 2010 were:
Cataracts (51%)
Glaucoma (8%)
Age-related macular degeneration (5%)
Corneal opacification (4%)
Childhood blindness (4%)
Refractive errors (3%)
Trachoma (3%)
Diabetic retinopathy (1%)
Undetermined (21%)
About 90% of people who are visually impaired live in the developing world. Age-related macular degeneration, glaucoma, and diabetic retinopathy are the leading causes of blindness in the developed world. | Visual impairment | Wikipedia | 411 | 2158298 | https://en.wikipedia.org/wiki/Visual%20impairment | Biology and health sciences | Disability | null |
Among working-age adults who are newly blind in England and Wales the most common causes in 2010 were:
Hereditary retinal disorders (20.2%)
Diabetic retinopathy (14.4%)
Optic atrophy (14.1%)
Glaucoma (5.9%)
Congenital abnormalities (5.1%)
Disorders of the visual cortex (4.1%)
Cerebrovascular disease (3.2%)
Degeneration of the macula and posterior pole (3.0%)
Myopia (2.8%)
Corneal disorders (2.6%)
Malignant neoplasms of the brain and nervous system (1.5%)
Retinal detachment (1.4%)
Cataracts
Cataracts are the greying or opacity of the crystalline lens, which can be caused in children by intrauterine infections, metabolic disorders, and genetically transmitted syndromes. Cataracts are the leading cause of child and adult blindness that doubles in prevalence with every ten years after the age of 40. Consequently, today cataracts are more common among adults than in children. That is, people face higher chances of developing cataracts as they age. Nonetheless, cataracts tend to have a greater financial and emotional toll upon children as they must undergo expensive diagnosis, long term rehabilitation, and visual assistance. Also, according to the Saudi Journal for Health Sciences, sometimes people experience irreversible amblyopia after pediatric cataract surgery because the cataracts prevented the normal maturation of vision prior to operation. Despite the great progress in treatment, cataracts remain a global problem in both economically developed and developing countries. At present, with the variant outcomes as well as the unequal access to cataract surgery, the best way to reduce the risk of developing cataracts is to avoid smoking and extensive exposure to sun light (i.e. UV-B rays). | Visual impairment | Wikipedia | 404 | 2158298 | https://en.wikipedia.org/wiki/Visual%20impairment | Biology and health sciences | Disability | null |
Glaucoma
Glaucoma is an eye disease often characterized by increased pressure within the eye or intraocular pressure (IOP). Glaucoma causes visual field loss as well as severs the optic nerve. Early diagnosis and treatment of glaucoma in patients is imperative because glaucoma is triggered by non-specific levels of IOP. Also, another challenge in accurately diagnosing glaucoma is that the disease has four causes: 1) inflammatory ocular hypertension syndrome (IOHS); 2) severe uveitic angle closure; 3) corticosteroid-induced; and 4) a heterogonous mechanism associated with structural change and chronic inflammation. In addition, often pediatric glaucoma differs greatly in cause and management from the glaucoma developed by adults. Currently, the best sign of pediatric glaucoma is an IOP of 21 mm Hg or greater present within a child. One of the most common causes of pediatric glaucoma is cataract removal surgery, which leads to an incidence rate of about 12.2% among infants and 58.7% among 10-year-olds.
Infections
Childhood blindness can be caused by conditions related to pregnancy, such as congenital rubella syndrome and retinopathy of prematurity. Leprosy and onchocerciasis each blind approximately 1 million individuals in the developing world.
The number of individuals blind from trachoma has decreased in the past 10 years from 6 million to 1.3 million, putting it in seventh place on the list of causes of blindness worldwide.
Central corneal ulceration is also a significant cause of monocular blindness worldwide, accounting for an estimated 850,000 cases of corneal blindness every year in the Indian subcontinent alone. As a result, corneal scarring from all causes is now the fourth greatest cause of global blindness.
Injuries
Eye injuries, most often occurring in people under 30, are the leading cause of monocular blindness (vision loss in one eye) throughout the United States. Injuries and cataracts affect the eye itself, while abnormalities such as optic nerve hypoplasia affect the nerve bundle that sends signals from the eye to the back of the brain, which can lead to decreased visual acuity. | Visual impairment | Wikipedia | 466 | 2158298 | https://en.wikipedia.org/wiki/Visual%20impairment | Biology and health sciences | Disability | null |
Cortical blindness results from injuries to the occipital lobe of the brain that prevent the brain from correctly receiving or interpreting signals from the optic nerve. Symptoms of cortical blindness vary greatly across individuals and may be more severe in periods of exhaustion or stress. It is common for people with cortical blindness to have poorer vision later in the day.
Blinding has been used as an act of vengeance and torture in some instances, to deprive a person of a major sense by which they can navigate or interact within the world, act fully independently, and be aware of events surrounding them. An example from the classical realm is Oedipus, who gouges out his own eyes after realizing that he fulfilled the awful prophecy spoken of him. Having crushed the Bulgarians, the Byzantine Emperor Basil II blinded as many as 15,000 prisoners taken in the battle, before releasing them. Contemporary examples include the addition of methods such as acid throwing as a form of disfigurement.
Genetic defects
People with albinism often have vision loss to the extent that many are legally blind, though few of them actually cannot see. Leber congenital amaurosis can cause total blindness or severe sight loss from birth or early childhood. Retinitis pigmentosa is characterized by decreased peripheral vision and trouble seeing at night.
Advances in mapping of the human genome have identified other genetic causes of low vision or blindness. One such example is Bardet–Biedl syndrome.
Poisoning
Rarely, blindness is caused by the intake of certain chemicals. A well-known example is methanol, which is only mildly toxic and minimally intoxicating, and breaks down into the substances formaldehyde and formic acid which in turn can cause blindness, an array of other health complications, and death. When competing with ethanol for metabolism, ethanol is metabolized first, and the onset of toxicity is delayed. Methanol is commonly found in methylated spirits, denatured ethyl alcohol, to avoid paying taxes on selling ethanol intended for human consumption. Methylated spirits are sometimes used by alcoholics as a desperate and cheap substitute for regular ethanol alcoholic beverages. | Visual impairment | Wikipedia | 435 | 2158298 | https://en.wikipedia.org/wiki/Visual%20impairment | Biology and health sciences | Disability | null |
Other
Amblyopia: is a category of vision loss or visual impairment that is caused by factors unrelated to refractive errors or coexisting ocular diseases. Amblyopia is the condition when a child's visual systems fail to mature normally because the child either has been born premature, measles, congenital rubella syndrome, vitamin A deficiency, or meningitis. If left untreated during childhood, amblyopia is currently incurable in adulthood because surgical treatment effectiveness changes as a child matures. Consequently, amblyopia is the world's leading cause of child monocular vision loss, which is the damage or loss of vision in one eye. In the best case scenario, which is very rare, properly treated amblyopia patients can regain 20/40 acuity.
Corneal opacification
Degenerative myopia
Diabetic retinopathy: is one of the manifestation microvascular complications of diabetes, which is characterized by blindness or reduced acuity. That is, diabetic retinopathy describes the retinal and vitreous hemorrhages or retinal capillary blockage caused by the increase of A1C, which a measurement of blood glucose or sugar level. In fact, as A1C increases, people tend to be at greater risk of developing diabetic retinopathy than developing other microvascular complications associated with diabetes (e.g. chronic hyperglycemia, diabetic neuropathy, and diabetic nephropathy). Despite the fact that only 8% of adults 40 years and older experience vision-threatening diabetic retinopathy (e.g. nonproliferative diabetic retinopathy or NPDR and proliferative diabetic retinopathy or PDR), this eye disease accounted for 17% of cases of blindness in 2002.
Retinitis pigmentosa
Retinopathy of prematurity: The most common cause of blindness in infants worldwide. In its most severe form, ROP causes retinal detachment, with attendant visual loss. Treatment is aimed mainly at prevention, via laser or Avastin therapy.
Stargardt's disease | Visual impairment | Wikipedia | 449 | 2158298 | https://en.wikipedia.org/wiki/Visual%20impairment | Biology and health sciences | Disability | null |
Uveitis: is a group of 30 intraocular inflammatory diseases caused by infections, systemic diseases, organ-specific autoimmune processes, cancer or trauma. That is, uveitis refers to a complex category of ocular diseases that can cause blindness if either left untreated or improperly diagnosed. The current challenge of accurately diagnosing uveitis is that often the cause of a specific ocular inflammation is either unknown or multi-layered. Consequently, about 3–10% of those with uveitis in developed countries, and about 25% of those with uveitis in the developing countries, become blind from incorrect diagnosis and from ineffectual prescription of drugs, antibiotics or steroids. In addition, uveitis is a diverse category of eye diseases that are subdivided as granulomatous (or tumorous) or non-granulomatous anterior, intermediate, posterior or pan uveitis. In other words, uveitis diseases tend to be classified by their anatomic location in the eye (e.g. uveal tract, retina, or lens), as well as can create complication that can cause cataracts, glaucoma, retinal damage, age-related macular degeneration or diabetic retinopathy.
Xerophthalmia, often due to vitamin A deficiency, is estimated to affect 5 million children each year; 500,000 develop active corneal involvement, and half of these go blind. | Visual impairment | Wikipedia | 306 | 2158298 | https://en.wikipedia.org/wiki/Visual%20impairment | Biology and health sciences | Disability | null |
Diagnosis
It is important that people be examined by someone specializing in low vision care prior to other rehabilitation training to rule out potential medical or surgical correction for the problem and to establish a careful baseline refraction and prescription of both normal and low vision glasses and optical aids. Only a doctor is qualified to evaluate visual functioning of a compromised visual system effectively. The American Medical Association provides an approach to evaluating visual loss as it affects an individual's ability to perform activities of daily living.
Screening adults who have no symptoms is of uncertain benefit.
Prevention
The World Health Organization estimates that 80% of visual loss is either preventable or curable with treatment. This includes cataracts, onchocerciasis, trachoma, glaucoma, diabetic retinopathy, uncorrected refractive errors, and some cases of childhood blindness. The Center for Disease Control and Prevention estimates that half of blindness in the United States is preventable.
Management
Mobility
Many people with serious visual impairments can travel independently, using a wide range of tools and techniques. Orientation and mobility specialists are professionals who are specifically trained to teach people with visual impairments how to travel safely, confidently, and independently in the home and the community. These professionals can also help blind people to practice travelling on specific routes which they may use often, such as the route from one's house to a convenience store. Becoming familiar with an environment or route can make it much easier for a blind person to navigate successfully.
Tools such as the white cane with a red tip – the international symbol of blindness – may also be used to improve mobility. A long cane is used to extend the user's range of touch sensation. It is usually swung in a low sweeping motion, across the intended path of travel, to detect obstacles. However, techniques for cane travel can vary depending on the user and/or the situation. Some visually impaired persons do not carry these kinds of canes, opting instead for the shorter, lighter identification (ID) cane. Still others require a support cane. The choice depends on the individual's vision, motivation, and other factors. | Visual impairment | Wikipedia | 428 | 2158298 | https://en.wikipedia.org/wiki/Visual%20impairment | Biology and health sciences | Disability | null |
A small number of people employ guide dogs to assist in mobility. These dogs are trained to navigate around various obstacles, and to indicate when it becomes necessary to go up or down a step. However, the helpfulness of guide dogs is limited by the inability of dogs to understand complex directions. The human half of the guide dog team does the directing, based upon skills acquired through previous mobility training. In this sense, the handler might be likened to an aircraft's navigator, who must know how to get from one place to another, and the dog to the pilot, who gets them there safely.
GPS devices can also be used as a mobility aid. Such software can assist blind people with orientation and navigation, but it is not a replacement for traditional mobility tools such as white canes and guide dogs.
Some blind people are skilled at echolocating silent objects simply by producing mouth clicks and listening to the returning echoes. It has been shown that blind echolocation experts use what is normally the "visual" part of their brain to process the echoes.
Government actions are sometimes taken to make public places more accessible to blind people. Public transportation is freely available to blind people in many cities. Tactile paving and audible traffic signals can make it easier and safer for visually impaired pedestrians to cross streets. In addition to making rules about who can and cannot use a cane, some governments mandate the right-of-way be given to users of white canes or guide dogs.
Reading and magnification
Most visually impaired people who are not totally blind read print, either of a regular size or enlarged by magnification devices. Many also read large-print, which is easier for them to read without such devices. A variety of magnifying glasses, some handheld, and some on desktops, can make reading easier for them.
Others read braille (or the infrequently used Moon type), or rely on talking books and readers or reading machines, which convert printed text to speech or braille. They use computers with special hardware such as scanners and refreshable braille displays as well as software written specifically for the blind, such as optical character recognition applications and screen readers.
Some people access these materials through agencies for the blind, such as the National Library Service for the Blind and Physically Handicapped in the United States, the National Library for the Blind or the RNIB in the United Kingdom. | Visual impairment | Wikipedia | 485 | 2158298 | https://en.wikipedia.org/wiki/Visual%20impairment | Biology and health sciences | Disability | null |
Closed-circuit televisions, equipment that enlarges and contrasts textual items, are a more high-tech alternative to traditional magnification devices.
There are also over 100 radio reading services throughout the world that provide people with vision impairments with readings from periodicals over the radio. The International Association of Audio Information Services provides links to all of these organizations.
Computers and mobile technology
Access technology such as screen readers, screen magnifiers and refreshable braille displays enable the blind to use mainstream computer applications and mobile phones. The availability of assistive technology is increasing, accompanied by concerted efforts to ensure the accessibility of information technology to all potential users, including the blind. Later versions of Microsoft Windows include an Accessibility Wizard & Magnifier for those with partial vision, and Microsoft Narrator, a simple screen reader. Linux distributions (as live CDs) for the blind include Vinux and Adriane Knoppix, the latter developed in part by Adriane Knopper who has a visual impairment. macOS and iOS also come with a built-in screen reader called VoiceOver, while Google TalkBack is built in to most Android devices.
The movement towards greater web accessibility is opening a far wider number of websites to adaptive technology, making the web a more inviting place for visually impaired surfers.
Experimental approaches in sensory substitution are beginning to provide access to arbitrary live views from a camera.
Modified visual output that includes large print and/or clear simple graphics can be of benefit to users with some residual vision.
Other aids and techniques | Visual impairment | Wikipedia | 309 | 2158298 | https://en.wikipedia.org/wiki/Visual%20impairment | Biology and health sciences | Disability | null |
Blind people may use talking equipment such as thermometers, watches, clocks, scales, calculators, and compasses. They may also enlarge or mark dials on devices such as ovens and thermostats to make them usable. Other techniques used by blind people to assist them in daily activities include:
Adaptations of coins and banknotes so that the value can be determined by touch. For example:
In some currencies, such as the euro, the pound sterling and the Indian rupee, the size of a note increases with its value.
On US coins, pennies and dimes, and nickels and quarters are similar in size. The larger denominations (dimes and quarters) have ridges along the sides (historically used to prevent the "shaving" of precious metals from the coins), which can now be used for identification.
Some currencies' banknotes have a tactile feature to indicate denomination. For example, the Canadian currency tactile feature is a system of raised dots in one corner, based on braille cells but not standard braille.
It is also possible to fold notes in different ways to assist recognition.
Labeling and tagging clothing and other personal items
Placing different types of food at different positions on a dinner plate
Marking controls of household appliances
Most people, once they have been visually impaired for long enough, devise their own adaptive strategies in all areas of personal and professional management.
For the blind, there are books in braille, audio-books, and text-to-speech computer programs, machines and e-book readers. Low vision people can make use of these tools as well as large-print reading materials and e-book readers that provide large font sizes.
Computers are important tools of integration for the visually impaired person. They allow, using standard or specific programs, screen magnification and conversion of text into sound or touch (braille line), and are useful for all levels of visual impairment. OCR scanners can, in conjunction with text-to-speech software, read the contents of books and documents aloud via computer. Vendors also build closed-circuit televisions that electronically magnify paper, and even change its contrast and color, for visually impaired users. For more information, consult assistive technology. | Visual impairment | Wikipedia | 464 | 2158298 | https://en.wikipedia.org/wiki/Visual%20impairment | Biology and health sciences | Disability | null |
In adults with low vision there is no conclusive evidence supporting one form of reading aid over another. In several studies stand-mounted devices allowed faster reading than hand-held or portable optical aids. While electronic aids may allow faster reading for individuals with low vision, portability, ease of use, and affordability must be considered for people.
Children with low vision sometimes have reading delays, but do benefit from phonics-based beginning reading instruction methods. Engaging phonics instruction is multisensory, highly motivating, and hands-on. Typically students are first taught the most frequent sounds of the alphabet letters, especially the so-called short vowel sounds, then taught to blend sounds together with three-letter consonant-vowel-consonant words such as cat, red, sit, hot, sun. Hands-on (or kinesthetically appealing) VERY enlarged print materials such as those found in "The Big Collection of Phonics Flipbooks" by Lynn Gordon (Scholastic, 2010) are helpful for teaching word families and blending skills to beginning readers with low vision. Beginning reading instructional materials should focus primarily on the lower-case letters, not the capital letters (even though they are larger) because reading text requires familiarity (mostly) with lower-case letters. Phonics-based beginning reading should also be supplemented with phonemic awareness lessons, writing opportunities, and many read-alouds (literature read to children daily) to stimulate motivation, vocabulary development, concept development, and comprehension skill development. Many children with low vision can be successfully included in regular education environments. Parents may need to be vigilant to ensure that the school provides the teacher and students with appropriate low vision resources, for example technology in the classroom, classroom aide time, modified educational materials, and consultation assistance with low vision experts.
Epidemiology
The WHO estimates that in 2012 there were 285 million visually impaired people in the world, of which 246 million had low vision and 39 million were blind.
Of those who are blind 90% live in the developing world. Worldwide for each blind person, an average of 3.4 people have low vision, with country and regional variation ranging from 2.4 to 5.5. | Visual impairment | Wikipedia | 445 | 2158298 | https://en.wikipedia.org/wiki/Visual%20impairment | Biology and health sciences | Disability | null |
By age: Visual impairment is unequally distributed across age groups. More than 82% of all people who are blind are 50 years of age and older, although they represent only 19% of the world's population. Due to the expected number of years lived in blindness (blind years), childhood blindness remains a significant problem, with an estimated 1.4 million blind children below age 15.
By gender: Available studies consistently indicate that in every region of the world, and at all ages, females have a significantly higher risk of being visually impaired than males.
By geography: Visual impairment is not distributed uniformly throughout the world. More than 90% of the world's visually impaired live in developing countries.
Since the estimates of the 1990s, new data based on the 2002 global population show a reduction in the number of people who are blind or visually impaired, and those who are blind from the effects of infectious diseases, but an increase in the number of people who are blind from conditions related to longer life spans.
In 1987, it was estimated that 598,000 people in the United States met the legal definition of blindness. Of this number, 58% were over the age of 65. In 1994–1995, 1.3 million Americans reported legal blindness.
Society and culture
Legal definition
To determine which people qualify for special assistance because of their visual disabilities, various governments have specific definitions for legal blindness. In North America and most of Europe, legal blindness is defined as visual acuity (vision) of 20/200 (6/60) or less in the better eye with best correction possible. This means that a legally blind individual would have to stand from an object to see itwith corrective lenseswith the same degree of clarity as a normally sighted person could from . In many areas, people with average acuity who nonetheless have a visual field of less than 20 degrees (the norm being 180 degrees) are also classified as being legally blind.
Approximately fifteen percent of those deemed legally blind, by any measure, have no light or form perception. The rest have some vision, from light perception alone to relatively good acuity. Low vision is sometimes used to describe visual acuities from 20/70 to 20/200.
Literature and art
Antiquity
The Moche people of ancient Peru depicted the blind in their ceramics. | Visual impairment | Wikipedia | 464 | 2158298 | https://en.wikipedia.org/wiki/Visual%20impairment | Biology and health sciences | Disability | null |
In Greek myth, Tiresias was a prophet famous for his clairvoyance. According to one myth, he was blinded by the gods as punishment for revealing their secrets, while another holds that he was blinded as punishment after he saw Athena naked while she was bathing. In the Odyssey, the one-eyed Cyclops Polyphemus captures Odysseus, who blinds Polyphemus to escape. In Norse mythology, Loki tricks the blind god Höðr into killing his brother Baldr, the god of happiness.
The New Testament contains numerous instances of Jesus performing miracles to heal the blind. According to the Gospels, Jesus healed the two blind men of Galilee, the blind man of Bethsaida, the blind man of Jericho and the man who was born blind.
The parable of the blind men and an elephant has crossed between many religious traditions and is part of Jain, Buddhist, Sufi and Hindu lore. In various versions of the tale, a group of blind men (or men in the dark) touch an elephant to learn what it is like. Each one feels a different part, but only one part, such as the side or the tusk. They then compare notes and learn that they are in complete disagreement.
"Three Blind Mice" is a medieval English nursery rhyme about three blind mice whose tails are cut off after chasing the farmer's wife. The work is explicitly incongruous, ending with the comment Did you ever see such a sight in your life, As three blind mice?
Modern times
Poet John Milton, who went blind in mid-life, composed "On His Blindness", a sonnet about coping with blindness. The work posits that [those] who best Bear [God]'s mild yoke, they serve him best.
The Dutch painter and engraver Rembrandt often depicted scenes from the apocryphal Book of Tobit, which tells the story of a blind patriarch who is healed by his son, Tobias, with the help of the archangel Raphael.
Slaver-turned-abolitionist John Newton composed the hymn "Amazing Grace" about a wretch who "once was lost, but now am found, Was blind, but now I see." Blindness, in this sense, is used both metaphorically (to refer to someone who was ignorant but later became knowledgeable) and literally, as a reference to those healed in the Bible. In the later years of his life, Newton himself would go blind. | Visual impairment | Wikipedia | 502 | 2158298 | https://en.wikipedia.org/wiki/Visual%20impairment | Biology and health sciences | Disability | null |
H. G. Wells' story "The Country of the Blind" explores what would happen if a sighted man found himself trapped in a country of blind people to emphasise society's attitude to blind people by turning the situation on its head.
José Saramago's novel Blindness describes a sudden mass blindness epidemic, and the main story follows the first group to lose their vision and how they have to adapt to their new disability amidst a decaying society.
Bob Dylan's anti-war song "Blowin' in the Wind" twice alludes to metaphorical blindness: How many times can a man turn his head // and pretend that he just doesn't see... How many times must a man look up // Before he can see the sky?
Contemporary fiction contains numerous well-known blind characters. Some of these characters can see by means of devices, such as the Marvel Comics superhero Daredevil, who can see via his super-human hearing acuity, or Star Trek Geordi La Forge, who can see with the aid of a VISOR, a fictional device that transmits optical signals to his brain.
Blind culture
People who are not blind often imagine that people who are blind share a cultural identity in the way that other minority groups with shared experiences have a distinct culture. Various blind commentators have responded to this perception by explaining that more commonly, blind people integrate with the broader community and culture, and often do not identify blindness as a defining part of their culture.
People who are blind share the common cultural experience of the many misconceptions sighted people have about living with blindness.
Sports
Blind and partially sighted people participate in sports, such as swimming, snow skiing and athletics. Some sports have been invented or adapted for the blind, such as goalball, association football, cricket, golf, tennis, bowling, and beep baseball. The worldwide authority on sports for the blind is the International Blind Sports Federation. People with vision impairments have participated in the Paralympic Games since the 1976 Toronto summer Paralympics. | Visual impairment | Wikipedia | 409 | 2158298 | https://en.wikipedia.org/wiki/Visual%20impairment | Biology and health sciences | Disability | null |
Metaphorical uses
The word "blind" (adjective and verb) is often used to signify a lack of knowledge of something. For example, a blind date is a date in which the people involved have not previously met; a blind experiment is one in which information is kept from either the experimenter or the participant to mitigate the placebo effect or observer bias. The expression "blind leading the blind" refers to incapable people leading other incapable people. Being blind to something means not understanding or being aware of it. A "blind spot" is an area where someone cannot see: for example, where a car driver cannot see because parts of his car's bodywork are in the way; metaphorically, a topic on which an individual is unaware of their own biases, and therefore of the resulting distortions of their own judgements (see Bias blind spot).
Research
A 2008 study tested the effect of using gene therapy to help restore the sight of patients with a rare form of inherited blindness, known as Leber's congenital amaurosis or LCA. Leber's Congenital Amaurosis damages the light receptors in the retina and usually begins affecting sight in early childhood, with worsening vision until complete blindness around the age of 30. The study used a common cold virus to deliver a normal version of the gene called RPE65 directly into the eyes of affected patients. All three patients, aged 19, 22 and 25, responded well to the treatment and reported improved vision following the procedure.
Two experimental treatments for retinal problems include a cybernetic replacement and transplant of fetal retinal cells.
There is no high-quality evidence on the effect of assistive technologies on educational outcomes and quality of life in children with low vision , nor is there evidence on magnifying reading aids in children. Low-vision rehabilitation does not appear to have an important impact on health-related quality of life, though some low-vision rehabilitation interventions, particularly psychological therapies and methods of enhancing vision, may improve vision-related quality of life in people with sight loss.
Other animals | Visual impairment | Wikipedia | 423 | 2158298 | https://en.wikipedia.org/wiki/Visual%20impairment | Biology and health sciences | Disability | null |
Statements that certain species of mammals are "born blind" refers to them being born with their eyes closed and their eyelids fused together; the eyes open later. One example is the rabbit. In humans, the eyelids are fused for a while before birth, but open again before the normal birth time; however, very premature babies are sometimes born with their eyes fused shut, and opening later. Other animals, such as the blind mole rat, are truly blind and rely on other senses.
The theme of blind animals has been a powerful one in literature. Peter Shaffer's Tony Award-winning play, Equus, tells the story of a boy who blinds six horses. Theodore Taylor's classic young adult novel, The Trouble With Tuck, is about a teenage girl, Helen, who trains her blind dog to follow and trust a seeing-eye dog. | Visual impairment | Wikipedia | 172 | 2158298 | https://en.wikipedia.org/wiki/Visual%20impairment | Biology and health sciences | Disability | null |
The Port of Hamburg (, ) is a seaport on the river Elbe in Hamburg, Germany, from its mouth on the North Sea.
Known as Germany's "Gateway to the World" (), it is the country's largest seaport by volume. In terms of TEU throughput, Hamburg is the third-busiest port in Europe (after Rotterdam and Antwerp) and 15th-largest worldwide. In 2014, 9.73 million TEUs (20-foot standard container equivalents) were handled in Hamburg.
The port covers an area of (64.80 km2 usable), of which 43.31 km2 (34.12 km2) are land areas. The branching Elbe creates an ideal place for a port complex with warehousing and transshipment facilities. The extensive free port was established when Hamburg joined the German Customs Union. It enabled duty-free storing of imported goods and also importing of materials which were processed, re-packaged, used in manufacturing and then re-exported without incurring customs duties. The free port was abandoned in 2013.
History
The port is almost as old as the history of Hamburg itself. Founded on 7 May 1189 by Frederick I at a strategic location near the mouth of the Elbe, it has been Central Europe's main port for centuries and enabled Hamburg to develop early into a leading city of trade with a rich and proud bourgeoisie.
During the age of the Hanseatic League from the 13th to 16th century, Hamburg was considered second only to the port and city of Lübeck in terms of its position as a central trading node for sea-borne trade. With discovery of the Americas and the emerging transatlantic trade, Hamburg exceeded all other German ports. During the second half of the 19th century, Hamburg became Central Europe's main hub for transatlantic passenger and freight travel, and from 1871 onward it was Germany's principal port of trade. In her time the Hamburg America Line was the largest shipping company in the world. Since 1888, the HADAG runs a scheduled ferry service across various parts of the port and the Elbe. The Free Port (Freihafen), established on 15 October 1888, enabled traders to ship and store goods without going through customs and further enhanced Hamburg's position in sea trade with neighbouring countries. It was permanently closed on 1 January 2013. The Moldauhafen has a similar arrangement, though related to the Czech Republic exclusively. | Port of Hamburg | Wikipedia | 495 | 2158876 | https://en.wikipedia.org/wiki/Port%20of%20Hamburg | Technology | Specific piers and ports | null |
The Speicherstadt, one of Hamburg's architectural icons today, is a large wharf area of 350,000 m2 floor area on the northern shore of the river, built in the 1880s as part of the free port and to cope with the growing quantity of goods stored in the port.
Hamburg shipyards lost fleets twice after World War I and World War II. Moreover, during World War II, Hamburg harbour was the hub destination of the Hamburg America Line, that assured the Nazi Party a connection to the United States for the import of oil and steel, and the export of manufactured goods from Germany thanks to container ships. The shipping line Hamburg-Amerikanische Packetfahrt-Aktien-Gesellschaft (HAPAG) gave the name to the so-called shipping company based in Hamburg which used to run the trades of goods on this route. In 1970, along with Norddeutscher Lloyd, the present-day active company Hapag-Lloyd was founded.
During the partition of Germany between 1945 and 1990, the Port of Hamburg lost much of its hinterland and consequently many of its trading connections. However, since German reunification, the fall of the Iron Curtain and European enlargement, Hamburg has made substantial ground as one of Europe's prime logistics centres and as one of the world's largest and busiest sea ports.
In 2022, the German government let the Chinese state-owned COSCO Shipping take a stake in ownership of the port.
Access
Deepening of the river Elbe for large vessels is controversial for ecological reasons. In part due to cooperation with Lower Saxony and Bremen to build a new container port (JadeWeserPort) in the deep waters of Jadebusen in Wilhelmshaven, Hamburg withdrew from this plan after a change of government in 2001.
Hamburg Port Authority
The port is administered by the Hamburg Port Authority. The Hamburg Port Authority is described as having adopted an innovative approach. In November 2016 the Hamburg Port Authority ordered a modern fireboat budgeted at 16 million euros.
Terminals
Cruise | Port of Hamburg | Wikipedia | 410 | 2158876 | https://en.wikipedia.org/wiki/Port%20of%20Hamburg | Technology | Specific piers and ports | null |
Hamburg is a major cruise destination and one of Europe's largest ports of call for cruise passengers traveling the Atlantic, or the Norwegian and Baltic Seas. The port is also a major location for shipbuilder and shipyards, designing, building and reconditioning yachts and cruise liners. Hamburg has three passenger terminals for cruise ships: Hamburg Cruise Center HafenCity, the Hamburg Cruise Center Altona and the Hamburg Cruise Center Steinwerder, all three capable of processing the world's largest cruise ships.
Culture
Hamburg's harbour is also one of the city's major attractions, both as a vital, industrial, and logistical centre, and as a backdrop for modern culture and harbour history. These include several museum ships, musical theatres, bars, restaurants, and hotels – and even a floating church.
The annual celebration of the port's birthday (Hafengeburtstag), during the first weekend of May, is one of Hamburg's biggest public events. National and international visitors come to experience the festivities. Tugboats perform "ballets", old galleons and new cruise ships are open for tours, and fireworks explode at night.
Tour guides on boat tours in the port are called "he lüchts" (Low German for "he is lying"), after an often used call of dock workers when they overheard the stories told to tourists. | Port of Hamburg | Wikipedia | 281 | 2158876 | https://en.wikipedia.org/wiki/Port%20of%20Hamburg | Technology | Specific piers and ports | null |
Sexual and reproductive health (SRH) is a field of research, health care, and social activism that explores the health of an individual's reproductive system and sexual well-being during all stages of their life. Sexual and reproductive health is more commonly defined as sexual and reproductive health and rights, to encompass individual agency to make choices about their sexual and reproductive lives.
The term can also be further defined more broadly within the framework of the World Health Organization's (WHO) definition of health―as "a state of complete physical, mental and social well-being, and not merely the absence of disease or infirmity"―. WHO has a working definition of sexual health (2006) as '“…a state of physical, emotional, mental and social well-being in relation to sexuality; it is not merely the absence of disease, dysfunction or infirmity. Sexual health requires a positive and respectful approach to sexuality and sexual relationships, as well as the possibility of having pleasurable and safe sexual experiences, free of coercion, discrimination and violence. For sexual health to be attained and maintained, the sexual rights of all persons must be respected, protected and fulfilled.” This includes sexual wellbeing, encompassing the ability of an individual to have responsible, satisfying and safe sex and the freedom to decide if, when and how often to do so. UN agencies in particular define sexual and reproductive health as including both physical and psychological well-being vis-à-vis sexuality. Furthermore, the importance of ensuring sexual lives are pleasurable and satisfying, and not only focused on negative consequences of sex has been emphasized by many agencies such as the World Association of Sexual Health as well as considering the positive impacts on health and well-being of safe and satisfying relationships. A further interpretation includes access to sex education, access to safe, effective, affordable and acceptable methods of birth control, as well as access to appropriate health care services, as the ability of women to go safely through pregnancy and childbirth could provide couples with the best chance of having a healthy infant. | Sexual and reproductive health | Wikipedia | 413 | 2159778 | https://en.wikipedia.org/wiki/Sexual%20and%20reproductive%20health | Biology and health sciences | Fields of medicine | null |
The critical Guttmacher- Lancet Commission on Sexual and reproductive health and rights states state Sexual and reproductive health and rights (SRHR) are essential for sustainable development because of their links to gender equality and women’s wellbeing, their impact on maternal, newborn, child, and adolescent health, and their roles in shaping future economic development and environmental sustainability. Yet progress towards fulfilling SRHR for all has been stymied because of weak political commitment, inadequate resources, persistent discrimination against women and girls, and an unwillingness to address issues related to sexuality openly and comprehensively. As a result, almost all of the 4·3 billion people of reproductive age worldwide will have inadequate sexual and reproductive health services over the course of their lives'.
Individuals face inequalities in reproductive health services. Inequalities vary based on socioeconomic status, education level, age, ethnicity, religion, and resources available in their environment. Low income individuals may lack access to appropriate health services and/or knowledge of how to maintain reproductive health. Additionally, many approaches involving women, families, and local communities as active stakeholders in interventions and strategies to improve reproductive health.
Overview
The WHO assessed in 2008 that "Reproductive and sexual ill-health accounts for 20% of the global burden of ill-health for women, and 14% for men." Reproductive health is a part of sexual and reproductive health and rights. According to the United Nations Population Fund (UNFPA), unmet needs for sexual and reproductive health deprive women of the right to make "crucial choices about their own bodies and futures", affecting family welfare. Women bear and usually nurture children, so their reproductive health is inseparable from gender equality. Denial of such rights also worsens poverty.
Adolescent health | Sexual and reproductive health | Wikipedia | 358 | 2159778 | https://en.wikipedia.org/wiki/Sexual%20and%20reproductive%20health | Biology and health sciences | Fields of medicine | null |
Adolescent health creates a major global burden and has a great deal of additional and diverse complications compared to adult reproductive health such as early pregnancy and parenting issues, difficulties accessing contraception and safe abortions, lack of healthcare access, and high rates of HIV, sexually transmitted infections and mental health issues. Each of those can be affected by outside political, economic and socio-cultural influences. For most adolescent females, they have yet to complete their body growth trajectories, therefore adding a pregnancy exposes them to a predisposition to complications. These complications range from anemia, malaria, HIV and other STIs, postpartum bleeding and other postpartum complications, mental health disorders such as depression and suicidal thoughts or attempts. In 2016, adolescent birth rates between the ages of 15-19 was 45 per 1000. In 2014, 1 in 3 experienced sexual violence, and there more than 1.2 million deaths. The top three leading causes of death in females between the ages of 15-19 are maternal conditions 10.1%, self-harm 9.6%, and road conditions 6.1%.
The causes of teenage pregnancy are vast and diverse. In developing countries, young women are pressured to marry for different reasons. One reason is to bear children to help with work, another on a dowry system to increase the families income, another is due to prearranged marriages. These reasons tie back to the financial needs of girls' families, cultural norms, religious beliefs, and external conflicts.
Adolescent pregnancy, especially in developing countries, carries increased health risks, and contributes to maintaining the cycle of poverty. The availability and type of sex education for teenagers varies in different parts of the world. Teens that are self-identified as non-heterosexual may develop additional problems if they live in places where homosexual activity is socially disapproved or even illegal; in extreme cases, there can be depression, social isolation, and even suicide among LGBT youth.
Maternal health | Sexual and reproductive health | Wikipedia | 396 | 2159778 | https://en.wikipedia.org/wiki/Sexual%20and%20reproductive%20health | Biology and health sciences | Fields of medicine | null |
95% of maternal deaths occur in low income contexts and countries, and in 25 years, the maternal mortality globally dropped to 44%. Statistically, a woman's chance of survival during childbirth is closely tied to her social-economic status, access to healthcare, where she lives geographically, and cultural norms. To compare, a woman dies of complications from childbirth every minute in developing countries versus a total of 1% of total maternal mortality deaths in developed countries. Women in developing countries have little access to family planning services, different cultural practices, lack of information, birthing attendants, prenatal care, birth control, postnatal care, lack of access to health care, and are typically in poverty. In 2015, those in low-income countries had access to antenatal care visits averaged 40% and were preventable. All these reasons led to an increase in the maternal mortality ratio (MMR).
One of the international Sustainable Development Goals developed by United Nations is to improve maternal health by a targeted 70 deaths per 100,000 live births by 2030. Most models of maternal health encompass family planning, preconception, prenatal, and postnatal care. All care after childbirth recovery is typically excluded, which includes pre-menopause and aging into old age. During childbirth, women typically die from severe bleeding, infections, high blood pressure during pregnancy, delivery complications, or an unsafe abortion. Other reasons can be regional such as complications related to diseases such as malaria and AIDS during pregnancy. The younger the woman is when she gives birth, the more at risk she and her baby are for complications and possible mortality. | Sexual and reproductive health | Wikipedia | 330 | 2159778 | https://en.wikipedia.org/wiki/Sexual%20and%20reproductive%20health | Biology and health sciences | Fields of medicine | null |
There is a significant relationship between the quality of maternal services made available and the greater financial standings of a country. Sub-Saharan Africa and South Asia exemplify this as these regions are significantly deprived of medical staff and affordable health
opportunities. Most countries provide for their health services through a combination of funding from government tax revenue and local households. Poorer nations or regions with extremely concentrated wealth can leave citizens on the margins uncared for or overlooked.
However, the lack of proper leadership can result in a nation's public sectors being mishandled or poorly performing despite said nation's resources and standing. In addition, poorer nations funding their medical services through taxes places a greater financial burden on the public and effectively the mothers themselves.
Responsibility and accountability on the part of mental health sectors are strongly emphasized as to what will remedy the poor quality of maternal health globally. The impact of different maternal health interventions across the globe stagger variously and are vastly uneven. This is the result of a lack of political and financial commitment to the issue as most safe motherhood programs internationally have to compete for significant funding. Some resolve that if global survival initiatives were promoted and properly funded it would prove to be mutually beneficial for the international community. Investing in maternal health would ultimately advance several issues such as gender inequality, poverty, and general global health standards. As it currently stands, pregnant women are subjugated to high financial costs throughout the duration of their term internationally which is highly taxing and strenuous.
In addition, if either parent has a genetic disease, there is risk of these being passed on to the children. Birth control or technical solutions (assisted reproductive technology) can be an option then. | Sexual and reproductive health | Wikipedia | 335 | 2159778 | https://en.wikipedia.org/wiki/Sexual%20and%20reproductive%20health | Biology and health sciences | Fields of medicine | null |
LGBT+ sexual and reproductive health
The sexual and reproductive health of LGBT+ people face challenges through issues like the ongoing HIV pandemic, binary organization of "men" and "women"'s reproductive health, alongside stigma and repression that limit LGBT+ people from accessing the healthcare they need. Sexual health is a state of physical, emotional, mental, and social well-being in relation to sexuality. It is important to not only consider the sexual/physical health of an individual but also the cultural and contextual factors that influence an individual's well-being. The lack of competent providers and stigma attached to homosexuality have a great impact on the sexual health of the LGBTQ+ population. The LGBTQ+ population faces a number of obstacles in terms of sexual and reproductive health. The different stigmas and biases that come with these barriers make receiving proper care difficult. Some of these stigmas that follow those in the LGBTQ+ population in terms of their sexual and reproductive health are associating certain diseases, and other illnesses with this community. This leaves those in the LGBTQ+ population in a position that makes them vulnerable, as well as victims of a number of health disparities. The overall health of those in the LGBTQ+ population is determinant on sexual and reproductive health as these all make up the health of these individuals. Those in the LGBTQ+ community face also face discrimination from providers and insurance companies, on top of all of the other barriers and limits on access to care that they endure. All of these factors have led to those in the LGBTQ+ population having worse health outcomes.
Contraception
Access to reproductive health services is very poor in many countries. Women are often unable to access maternal health services due to a lack of knowledge about the existence of such services or lack of freedom of movement. Some women are subjected to forced pregnancy and banned from leaving the home. In many countries, women are not allowed to leave home without a male relative or husband, and therefore their ability to access medical services is limited. Therefore, increasing women's autonomy is needed in order to improve reproductive health, however, doing so may require a cultural shift. According to the WHO, "All women need access to antenatal care in pregnancy, skilled care during childbirth, and care and support in the weeks after childbirth". | Sexual and reproductive health | Wikipedia | 471 | 2159778 | https://en.wikipedia.org/wiki/Sexual%20and%20reproductive%20health | Biology and health sciences | Fields of medicine | null |
The fact that the law allows certain reproductive health services, does not necessarily ensure that such services are actually in use by the people. The availability of contraception, sterilization, and abortion is dependent on laws, as well as social, cultural, and religious norms. Some countries have liberal laws regarding these issues, but in practice, it is very difficult to access such services due to doctors, pharmacists, and other social and medical workers being conscientious objectors.
In developing regions of the world, there are about 214 million women who want to avoid pregnancy but are unable to use safe and effective family planning methods. When taken correctly, the combined oral contraceptive pill is over 99% effective at preventing pregnancy. However, it does not protect from sexually transmitted infections (STIs). Some methods, such as using condoms, achieve both protection from STIs and unwanted pregnancies. There are also natural family planning methods, which may be preferred by religious people, but some very conservative religious groups, such as the Quiverfull movement, oppose these methods too because they advocate the maximization of procreation. One of the oldest ways to reduce unwanted pregnancy is coitus interruptus - still widely used in the developing world.
There are many types of contraceptives. One type of contraceptive includes barrier methods. One barrier method includes condoms for males and females. Both types stop sperm from entering the woman's uterus, thereby preventing pregnancy from occurring. Another type of contraception is the birth control pill, which stops ovulation from occurring by combining the chemicals progestin and estrogen. Many women use this method of contraception, however, they discontinue using it equally as much as they use it. One reason for this is because of the side effects that may occur from using the pill, and because some health care providers do not take women's concerns about negative side effects seriously. The use of the birth control pill is common in western countries, and two forms of combined oral contraceptives are on the World Health Organization's List of Essential Medicines, the most important medications needed in a basic health system. | Sexual and reproductive health | Wikipedia | 437 | 2159778 | https://en.wikipedia.org/wiki/Sexual%20and%20reproductive%20health | Biology and health sciences | Fields of medicine | null |
There are many objections to the use of birth control, both historically and in the present day. One argument against birth control usage states that there is no need for birth control, to begin with. This argument was levied in 1968 when Richard Nixon was elected president, and the argument stated that since birth rates were at their lowest point since World War II ended, birth control was not necessary. Demographic planning arguments were also the basis of the population policy of Nicolae Ceaușescu in communist Romania, who adopted a very aggressive natalist policy which included outlawing abortion and contraception, routine pregnancy tests for women, taxes on childlessness, and legal discrimination against childless people. Such policies consider that coercion is an acceptable means of reaching demographic targets. Religious objections are based on the view that premarital sex should not happen, while married couples should have as many children as possible. As such, the Catholic Church encourages premarital abstinence from sex. This argument was written out in Humanae Vitae, a papal encyclical released in 1968. The Catholic Church bases its argument against birth control pills on the basis that birth control pills undermine the natural law of God. The Catholic Church also argues against birth control on the basis of family size, with Cardinal Mercier of Belgium arguing, "...the duties of conscience are above worldly considerations, and besides, it is the large families who are the best" (Reiterman, 216). Another argument states that women should use natural methods of contraception in place of artificial ones, such as having sexual intercourse when one is infertile.
Support for contraception is based on views such as reproductive rights, women's rights, and the necessity to prevent child abandonment and child poverty. The World Health Organization states that "By preventing unintended pregnancy, family planning /contraception prevents deaths of mothers and children".
Sexually transmitted infection
A sexually transmitted infection (STI) --previously known as a sexually transmitted disease (STD) or venereal disease (VD)-- is an infection that has a significant likelihood of transmission between humans by means of sexual activity. The CDC analyses the eight most common STIs: chlamydia, gonorrhea, hepatitis B virus (HBV), herpes simplex virus type 2 (HSV-2), human immunodeficiency virus (HIV), human papillomavirus (HPV), syphilis, and trichomoniasis. | Sexual and reproductive health | Wikipedia | 511 | 2159778 | https://en.wikipedia.org/wiki/Sexual%20and%20reproductive%20health | Biology and health sciences | Fields of medicine | null |
There are 1 million new infections a day and more than 20 million new cases within the United States. In 2020, WHO estimated 374 million new infections with 1 of 4 STIs: chlamydia (129 million), gonorrhoea (82 million), syphilis (7.1 million) and trichomoniasis (156 million). More than 490 million people were estimated to be living with genital herpes in 2016, and an estimated 300 million women have an HPV infection, the primary cause of cervical cancer and anal cancer among men who have sex with men.
Numbers of such high magnitude weigh a heavy burden on the local and global economy. A study conducted at Oxford University in 2015 concluded that despite giving participants early antiviral medications (ART), they still cost an estimated $256 billion over 2 decades. HIV testing done at modest rates could reduce HIV infections by 21%, HIV retention by 54%, and HIV mortality rates by 64%, with a cost-effectiveness ratio of $45,300 per quality-adjusted life year. However, the study concluded that the United States has led to an excess in infections, treatment costs, and deaths, even when interventions do not improve overall survival rates.
There is a profound reduction in STI rates once those who are sexually active are educated about transmissions, condom promotion, interventions targeted at key and vulnerable populations through comprehensive sex education courses or programs. Recent evidence shows that acknowledging the role pleasure takes in people's sexual lives and integrating this in sexual health services and education has a significant impact on increasing condom use and improved sexual health outcomes. South Africa's policy addresses the needs of women at risk for HIV and who are HIV positive as well as their partners and children. The policy also promotes screening activities related to sexual health such as HIV counseling and testing as well as testing for other STIs, tuberculosis, cervical cancer, and breast cancer.
The CDC stated that the rate of sexually transmitted infections is higher among minorities compared to white people. These minorities are currently being affected by different factors including health literacy, socioeconomic status, access to health services, and fear of discrimination by health providers. The rates of infection are five to eight times higher in the Black community compared to non-Hispanic White people. | Sexual and reproductive health | Wikipedia | 460 | 2159778 | https://en.wikipedia.org/wiki/Sexual%20and%20reproductive%20health | Biology and health sciences | Fields of medicine | null |
Young African American women are at a higher risk for STIs, including HIV. A recent study published outside of Atlanta, Georgia collected data (demographic, psychological, and behavioral measures) with a vaginal swab to confirm the presence of STIs. They found a profound difference that those women who had graduated from college were far less likely to have STIs, potentially be benefiting from a reduction in vulnerability to acquiring STIs/HIV as they gain in education status and potentially move up in demographic areas and/or status.
Abortion
Globally, an estimated 25 million unsafe abortions occur each year. The vast majority of such unsafe abortions occur in developing countries in Africa, Asia and Latin America.
The abortion debate is the ongoing controversy surrounding the moral, legal, and religious status of induced abortion. The sides involved in the debate are the self-described "pro-choice" and "pro-life" movements. "Pro-choice" emphasizes the right of women to decide whether to terminate a pregnancy. "Pro-life" emphasizes the right of the embryo or fetus to gestate to term and be born. Both terms are considered loaded in mainstream media, where terms such as "abortion rights" or "anti-abortion" are generally preferred. Each movement has, with varying results, sought to influence public opinion and to attain legal support for its position, with small numbers of radical activists using violence, such as murder and arson.
Articles from the World Health Organization call legal abortion a fundamental right of women regardless of where they live, and argue that unsafe abortion is a silent pandemic. In 2005, it was estimated that 19-20 million abortions had complications, some complications are permanent, while another estimated 68,000 women died from unsafe abortions. Having access to safe abortion can have positive impacts on women's health and life, and vice versa. "Legislation of abortion on request is necessary but an insufficient step towards improving women's health. In some countries where it abortion is legal and has been for decades, there has been no improvement in access to adequate services making abortion unsafe due to lack of healthcare services. It is hard to get an abortion due to legal and policy barriers, social and cultural barriers (gender discrimination, poverty, religious restrictions, lack of support), health system barriers (lack of facilities or trained personnel). However, safe abortions with trained personnel, good social support, and access to facilities, can improve maternal health and increase reproductive health later in life. | Sexual and reproductive health | Wikipedia | 503 | 2159778 | https://en.wikipedia.org/wiki/Sexual%20and%20reproductive%20health | Biology and health sciences | Fields of medicine | null |
The Maputo Protocol, which was adopted by the African Union in the form of a protocol to the African Charter on Human and Peoples' Rights, states at Article 14 (Health and Reproductive Rights) that: "(2). States Parties shall take all appropriate measures to: [...] c) protect the reproductive rights of women by authorising medical abortion in cases of sexual assault, rape, incest, and where the continued pregnancy endangers the mental and physical health of the mother or the life of the mother or the foetus." The Maputo Protocol is the first international treaty to recognize abortion, under certain conditions, as a woman's human right.
The General comment No. 36 (2018) on article 6 of the International Covenant on Civil and Political Rights, on the right to life, adopted by the Human Rights Committee in 2018, defines, for the first time ever, a human right to abortion - in certain circumstances (however these UN general comments are considered soft law, and, as such, not legally binding).
When negotiating the Cairo Programme of Action at the 1994 International Conference on Population and Development (ICPD), the issue was so contentious that delegates eventually decided to omit any recommendation to legalize abortion, instead advising governments to provide proper post-abortion care and to invest in programs that will decrease the number of unwanted pregnancies.
The Committee on the Elimination of Discrimination against Women considers the criminalization of abortion a "violations of women's sexual and reproductive health and rights" and a form of "gender based violence"; paragraph 18 of its General recommendation No. 35 on gender based violence against women, updating general recommendation No. 19 states that: "Violations of women's sexual and reproductive health and rights, such as forced sterilizations, forced abortion, forced pregnancy, criminalisation of abortion, denial or delay of safe abortion and post abortion care, forced continuation of pregnancy, abuse and mistreatment of women and girls seeking sexual and reproductive health information, goods and services, are forms of gender based violence that, depending on the circumstances, may amount to torture or cruel, inhuman or degrading treatment." The same General Recommendation also urges countries at paragraph 31 to [...] In particular, repeal:
a) Provisions that allow, tolerate or condone forms of gender based violence against women, including [...] legislation that criminalises abortion". | Sexual and reproductive health | Wikipedia | 490 | 2159778 | https://en.wikipedia.org/wiki/Sexual%20and%20reproductive%20health | Biology and health sciences | Fields of medicine | null |
In 2008, the Parliamentary Assembly of the Council of Europe, a group comprising members from 47 European countries, has adopted a resolution calling for the decriminalization of abortion within reasonable gestational limits and guaranteed access to safe abortion procedures. The nonbinding resolution was passed on April 16 by a vote of 102 to 69.
Accesses to abortion is not only a question of legality but also an issue of overcoming de facto barriers, such as conscientious objections from medical staff, high prices, lack of knowledge about the law, lack of access to medical care (especially in rural areas). The de facto inability of women to access abortion even in countries where it is legal is highly controversial because it results in a situation where women have rights only on paper, not in practice; the UN in its 2017 resolution on Intensification of efforts to prevent and eliminate all forms of violence against women and girls: domestic violence urged states to guarantee access to "safe abortion where such services are permitted by national law".
There are two primary arguments for maintaining legalized abortion today in the U.S. The first is recognizing the full citizenship of women. The Roe v. Wade'' court case on abortion compared the citizenship of women and fetuses Because the Constitution defines born people as citizens, Justice Harry Blackmun ruled that fetuses were not citizens. The citizenship of women is emphasized because fetuses are not individual entities that can exist without the woman. Another reason why the full citizenship of women is defined by advocates for abortion is that it recognizes the right of women to manage their own bodies. Fertility affects women's bodies. The argument for abortion prevents others from making decisions that alter a woman's body. Pro-choice advocates also attempt to confirm that state-mandated education or other outside biases do not attempt to influence these decisions. Feminists argue that women throughout history have had to justify their citizenship politically and socially. The right to manage one's own body is a matter of health, safety, and respect. The citizenship of women and the right to manage their own bodies is a societal confirmation that feminists highlight as a pro-choice justification. | Sexual and reproductive health | Wikipedia | 437 | 2159778 | https://en.wikipedia.org/wiki/Sexual%20and%20reproductive%20health | Biology and health sciences | Fields of medicine | null |
The second primary argument to uphold legalized abortion and creating better access to it is the necessity of abortion and the health and safety of pregnant women. There are two events that largely changed the course of public opinion about abortion in the U.S. The first is Sherry Finkbine, who was denied access to an abortion by the board of obstetrician-gynecologists at her local hospital. Although she was privileged enough to afford the trip, Finkbine was forced to travel to Sweden for an abortion to avoid caring for a damaged fetus in addition to four children. The other event that changed public opinion was the outbreak of rubella in the 1950s and 60s. Because rubella disrupted the growth of fetuses and caused deformities during pregnancy, the California Therapeutic Abortion Act was signed in 1967, permitting doctors to legally abort pregnancies that pose a risk to a pregnant woman's physical or mental health. These two events are commonly used to show how the health and safety of pregnant women are contingent upon abortions as well as the ability to give birth to and adequately take care of a child. Another argument in favor of legalized abortion to service necessity are the reasons why an abortion might be necessary. Nearly half of all pregnancies in the United States are unintended, and over half of all unintended pregnancies in the United States are met with abortion. Unintended pregnancy can lead to serious harm to women and children for reasons such as not being able to afford to raise a baby, inaccessibility to time off of work, difficulties facing single motherhood, difficult socio-economic conditions for women. Unintended pregnancies also have a greater potential for putting women of color at risk due to systematically produced environmental hazards from proximity to pollution, access to livable income, and affordable healthy food. These factors as threats to the health and safety of pregnant women run parallel to data that shows the number of abortions in the United States did not decline while laws restricting legal access to abortion were implemented.
At a global level, the region with the strictest abortion laws is considered to be Latin America (see Reproductive rights in Latin America), a region strongly influenced by the Catholic Church in Latin America.
Female genital mutilation | Sexual and reproductive health | Wikipedia | 463 | 2159778 | https://en.wikipedia.org/wiki/Sexual%20and%20reproductive%20health | Biology and health sciences | Fields of medicine | null |
Female genital mutilation (FGM), also known as female genital circumcision or cutting, is the traditional, non-medical practice of altering or injuring the female reproductive organs, often by removing all or parts of the external genitalia. It is mostly practiced in 30 countries in Africa, the Middle East, and Asia, and affects over 200 million women and girls worldwide. More severe forms of FGM are highly concentrated in Djibouti, Eritrea, Ethiopia, Somalia, and Sudan.
The WHO categorizes FGM into four types:
Type I (Clitoridectomy) is the removal of all or part of the clitoris. This may or may not include removing the prepuce along with the clitoral glans.
Type II (Excision) is the removal of the clitoris along with all or part of the labia minora. This may or may not include removing all or part of the labia majora.
Type III (Infibulation) is the act of removing the inner or outer labia and sealing the wound, leaving only a narrow opening.
Type IV refers to "all other harmful procedures to the female genitalia for non-medical purposes (piercing, scraping, cauterizing of the genital area)."
FGM often takes the form of a traditional celebration conducted by an elder or community leader. The age that women undergo the procedure varies depending on the culture, although it is most commonly performed on prepubescent girls. Certain cultures value FGM as a coming of age ritual for girls and use it to preserve a woman's virginity and faithfulness to the husband after marriage. It is also closely connected with some traditional ideals of female beauty and hygiene. FGM may or may not have religious connotations depending on the circumstances. | Sexual and reproductive health | Wikipedia | 373 | 2159778 | https://en.wikipedia.org/wiki/Sexual%20and%20reproductive%20health | Biology and health sciences | Fields of medicine | null |
There are no health benefits of FGM, as it interferes with the natural functions of a woman's and girls' bodies, such as causing severe pain, shock, hemorrhage, tetanus or sepsis (bacterial infection), urine retention, open sores in the genital region and injury to nearby genital tissue, recurrent bladder and urinary tract infections, cysts, increased risk of infertility, childbirth complications and newborn deaths. Sexual problems are 1.5 more likely to occur in women who have undergone FGM, they may experience painful intercourse, have less sexual satisfaction, and be two times more likely to report a lack of sexual desire. In addition, the maternal and fetal death rate is significantly higher due to childbirth complications.
FGM can have severe negative psychological effects on women, both during and after the procedure. These can include long-term symptoms of depression, anxiety, post-traumatic stress disorder, and low self-esteem. Some women report that the procedure was carried out without their consent and knowledge, and describe feelings of fear and helplessness while it was taking place. A 2018 study found that larger quantities of the hormone cortisol were secreted in women who had undergone FGM, especially those who had experienced more severe forms of the procedure and at an early age. This marks the body's chemical response to trauma and stress and can indicate a greater risk for developing symptoms of PTSD and other trauma disorders, although there are limited studies showing a direct correlation.
The Istanbul Convention prohibits FGM (Article 38). Legislation has been introduced in certain countries to prevent FGM. A 2016 survey of 30 countries showed 24 had policies to manage and prevent FGM, although the process to provide funding, education, and resources were often inconsistent and lacking. Some countries have seen a slight decline in FGM rates, while others show little to no change.
Child and forced marriage
The practice of forcing young girls into early marriage, common in many parts of the world, is threatening their reproductive health. According to the World Health Organization:
Niger has the highest prevalence of child marriage under 18 in the world, while Bangladesh has the highest rate of marriage of girls under age 15. Practices such as bride price and dowry can contribute to child and forced marriages. | Sexual and reproductive health | Wikipedia | 462 | 2159778 | https://en.wikipedia.org/wiki/Sexual%20and%20reproductive%20health | Biology and health sciences | Fields of medicine | null |
International Conference on Population and Development, 1994
The International Conference on Population and Development (ICPD) was held in Cairo, Egypt, from 5 to 13 September 1994. Delegations from 179 States took part in negotiations to finalize a Programme of Action on population and development for the next 20 years. Some 20,000 delegates from various governments, UN agencies, NGOs, and the media gathered for a discussion of a variety of population issues, including immigration, infant mortality, birth control, family planning, and the education of women.
In the ICPD Program of Action, 'reproductive health' is defined as:
This definition of the term is also echoed in the United Nations Fourth World Conference on Women, or the so-called Beijing Declaration of 1995. However, the ICPD Program of Action, even though it received the support of a large majority of UN Member States, does not enjoy the status of an international legal instrument; it is therefore not legally binding.
The Program of Action endorses a new strategy which emphasizes the numerous linkages between population and development and focuses on meeting the needs of individual women and men rather than on achieving demographic targets. The ICPD achieved consensus on four qualitative and quantitative goals for the international community, the final two of which have particular relevance for reproductive health:
Reduction of maternal mortality: A reduction of maternal mortality rates and a narrowing of disparities in maternal mortality within countries and between geographical regions, socio-economic and ethnic groups.
Access to reproductive and sexual health services including family planning: Family planning counseling, pre-natal care, safe delivery and post-natal care, prevention and appropriate treatment of infertility, prevention of abortion and the management of the consequences of abortion, treatment of reproductive tract infections, sexually transmitted infections and other reproductive health conditions; and education, counseling, as appropriate, on human sexuality, reproductive health, and responsible parenthood. Services regarding HIV/AIDS, breast cancer, infertility, delivery, hormone therapy, sex reassignment therapy, and abortion should be made available. Active discouragement of female genital mutilation (FGM).
The keys to this new approach are empowering women, providing them with more choices through expanded access to education and health services, and promoting skill development and employment. The programme advocates making family planning universally available by 2015 or sooner, as part of a broadened approach to reproductive health and rights, provides estimates of the levels of national resources and international assistance that will be required, and calls on governments to make these resources available. | Sexual and reproductive health | Wikipedia | 508 | 2159778 | https://en.wikipedia.org/wiki/Sexual%20and%20reproductive%20health | Biology and health sciences | Fields of medicine | null |
Sustainable Development Goals
Half of the development goals put on by the United Nations started in 2000 to 2015 with the Millennium Development Goals (MDGs). Reproductive health was Goal 5 out of 8. To monitor the progress, the UN agreed to four indicators:
Contraceptive prevalence rates
Adolescent birth rate
Antenatal care coverage
Unmet need for family planning
Progress was slow, and according to the WHO in 2005, about 55% of women did not have sufficient antenatal care and 24% had no access to family planning services. The MDGs expired in 2015 and were replaced with a more comprehensive set of goals to cover a span of 2016–2030 with a total of 17 goals, called the Sustainable Development Goals. All 17 goals are comprehensive in nature and build off one another, but goal 3 is "To ensure healthy lives and promote wellbeing for all at all ages". Specific targets are to reduce global maternal mortality ratio to less than 70 per 100,000 live births, end preventable deaths of newborns and children, reduce the number by 50% of accidental deaths globally, strengthen the treatment and prevention programs of substance abuse and alcohol. Goal 4 emphasizes the fact that no one should be left out in providing quality education. Target 4 specifically mentions the inclusion of persons with disabilities, indigenous peoples and children in vulnerable situations. In addition, one of the targets of the Sustainable Development Goal 5 is to ensure universal access to sexual and reproductive health.
By region
North America
The CDC estimated that one in five people in the US had a sexually transmitted infection (STI) totalling near about 68 million infections in 2018. 26 million new STI in 2018. Almost half of new STI were among youth aged 15 to 24 in the US. New STIs total $16 billion in direct medical costs.
Engaging in oral sex can carry the risk of sexually transmitted infections (STIs). | Sexual and reproductive health | Wikipedia | 377 | 2159778 | https://en.wikipedia.org/wiki/Sexual%20and%20reproductive%20health | Biology and health sciences | Fields of medicine | null |
AfricaHIV/AIDSHIV/AIDS in Africa is a major public health problem. The population of Sub-Saharan Africa is the worst affected region with the disease especially affecting the young female population. According to the National Library of Medicine, "Sub Saharan Africa (SSA) is occupied by 12% of the global population, but disproportionately has more than 90% of children younger than 15 years of age and 68% of adults that are living with HIV2." In Nigeria in specific, "There is early sexual maturity and considerable sexual activity between 9 and 15 years of age." HIV is also transmissible through breast milk, which proves that women infected with HIV/AIDS have to deal with more health consequences. South of the Sahara, the AIDS epidemic is the leading cause of death. | Sexual and reproductive health | Wikipedia | 164 | 2159778 | https://en.wikipedia.org/wiki/Sexual%20and%20reproductive%20health | Biology and health sciences | Fields of medicine | null |
The reasons for the high spread of HIV/AIDS can be broken down into 7 main subsections: poverty, inadequate medical care, lack of prevention and education, taboo and stigma, sexual behavior, prostitution, and sexual violence against women. With a high population of individuals living in extreme poverty, condoms, HIV tests, and other forms of screening are not prioritized, leaving many individuals lacking the necessities to protect themselves from the disease. According to the International Finance Corporation, "Health care in Sub-Saharan Africa remains the worst in the world, with few countries able to spend the $34 to $40 a year per person that the World Health Organization considers the minimum for basic health care." Notably, though widespread poverty, "an astonishing 50 percent of the region's health expenditure is financed by out-of-pocket payments from individuals." This represents the lack of both affordability and accessibility surrounding the health care system in Sub-Saharan Africa. According to the United Nation, Sub-Saharan Africa struggles with the highest rate of education exclusion in the world; 60% of youth ages 15 to 17 are not in school. With this lack of education, information regarding HIV/AIDS and prevention practices are not transmitted to a number of individuals, leading to more citizens being unaware of the severity of the disease. Stigma surrounding HIV/AIDS further contributes to the high infection rate. In African villages, an individual's life is closely intertwined with their friends, families, and neighbors around them. Individuals who have HIV/AIDS are motivated to keep it a secret in fear of isolation and alienation. The extremity of this stigma is conveyed by some of the dialogue, people living with HIV are often ridiculed as "a walking corpse", referred to as "an HIV" and even called in Tanzania, "nyambizi", or submarine, which implies that an HIV-positive person is "menacing and deadly." Sexual behavior and prostitution also play a part in the increased rate of transmission of HIV/AIDS in Africa. Due to the high rates of poverty, prostitution is widespread, and sexual partners are often changing, increasing the likelihood of transmission. Africa has one of the highest rates of rape in the world, with many women getting AIDS due to raped and sexual violence by an HIV-infected offender | Sexual and reproductive health | Wikipedia | 468 | 2159778 | https://en.wikipedia.org/wiki/Sexual%20and%20reproductive%20health | Biology and health sciences | Fields of medicine | null |
Similarly, gender roles within many African countries contribute to this, as "in much of sub-Saharan Africa, women are a subordinate group who are expected to become pregnant, bear children, and fulfill the sexual desires of their husbands without hesitation".Fertility rates and contraceptivesIn most African countries, the total fertility rate is very high often due to a lack of access to contraception, family planning, and practices such as forced child marriage. For instance, Niger, Angola, Mali, Burundi, Somalia and Uganda have very high fertility rates. According to the United Nations Department of Economic and Social Affairs, "Africa has the lowest rate of contraceptive use (33%) and the highest rate of unmet need for contraceptives (22%)." In Mozambique, despite efforts in improving access to modern contraceptive methods, the general fertility rate is "still high at 5.3 and the unmet need for contraceptives is also high at 26%." Among young women, the fertility rate has dramatically increased from 167 births per 1000 aged between (15–19 years) in 2011 to 194 in 2015 with a large increase in rural areas from 183 to 230. Contraceptive prevalence among (15–19 years) remains low at 14% in 2015 when compared to the national prevalence among the reproductive age group (15–49 years) at 25% in the same year.Types of contraceptivesThe copper IUD has been provided less frequently than other contraceptive methods but there have been signs of an increase in most reported provinces. The most frequently provided methods are implants and injectable progesterone, which is not as ideal as condom usage, which is still required with this method to decrease the risk of HIV. In Nigeria, specifically, people who have multiple partners are often unwilling to protect themselves with condoms. "In a study conducted in a rural community in South West Nigeria in 1993, it was found that although 94.7% of 302 candidates aged between 20 and 54 years admitted hearing about the condom, only 51.3% admitted ever using it." According to the International Family Planning Perspective, "these injectable progesterone products made up 49% of South Africa's contraceptive use and up to 90% in some provinces." Though contraceptive use is rising in African countries, discontinuation rates are also high. Weak health systems challenge Sub-Saharan African countries in expanding contraceptive outreach, promotions and service | Sexual and reproductive health | Wikipedia | 497 | 2159778 | https://en.wikipedia.org/wiki/Sexual%20and%20reproductive%20health | Biology and health sciences | Fields of medicine | null |
Contraceptive accessibilityThe updated contraceptive guidelines in South Africa attempt to improve accessibility by providing special service delivery and prompting awareness for adolescents, lesbian, gay, bisexual, transgender, intersex people, disabled people, chronically ill people, women who are perimenopausal, sex workers, migrants and males. They also aim to increase access to long-acting contraceptive methods such as the copper IUD, the single rod progestogen implant combined with estrogen and progesterone injectables. Tanzanian provider perspectives also realized the biggest obstacle in maintaining healthy contraceptive care in their communities: lack of consistency. Contraceptive dispensaries found that the capability of providing service to patients was inconsistent and substandard. This resulted in unsatisfied reproductive goals, low educational attainment, miseducation about the side effects of certain contraceptives | Sexual and reproductive health | Wikipedia | 179 | 2159778 | https://en.wikipedia.org/wiki/Sexual%20and%20reproductive%20health | Biology and health sciences | Fields of medicine | null |
Accessibility has also been hindered as a result of inadequate quantities of properly trained medical personnel. According to the African Journal of Reproductive Health, "Shortage of the medical attendant...is a challenge, we are not able to attend to a big number of clients, also we do not have enough education which makes us unable to provide women with the methods they want". The majority of medical centers are staffed by people without medical training and few doctors and nurses, despite federal regulations, due to lack of resources. One center had only one person who was able to insert and remove implants, and without her, they were unable to service people who required this method of contraceptive care. Another dispensary which carried two methods of birth control shared that they sometimes run out of both materials at the same time which makes it difficult to keep up with the supply and demand chain.Social factors effect on contraceptivesUnbalanced gender dynamics, spousal dynamics, economic conditions, religious norms, cultural norms, and constraints in supply chains all contribute to contraceptive rates and usage. One instance of this is a provider who referenced harmful propaganda about the side effects of contraceptive usage. The spread of this propaganda is one of the many examples of influential people in the community, such as elders and religious leaders, discouraging proper contraceptive care/health. In some cases, influential members of the community often convince others that condoms and contraceptive pills contain microorganisms that cause cancer. | Sexual and reproductive health | Wikipedia | 298 | 2159778 | https://en.wikipedia.org/wiki/Sexual%20and%20reproductive%20health | Biology and health sciences | Fields of medicine | null |
In regards to spousal and gendered dynamics, many women often have faced pressure from their spouse or family members to use avoid birth control which resulted in them using it secretly. This is also one of the many reasons women frequently preferred undetectable contraceptive methods which can lead to less effective contraceptives.Other common sexually transmitted infections in Sub-Saharan AfricaSub-Saharan Africa ranks first in STI yearly incidence compared to other world regions, reiterating the major problem that public health is in African countries. In Sub-Saharan Africa, STIs are the most common reasons that individuals seek medical care. According to the World Health Organization, every year in Africa "there are 3.5 million cases of syphilis, 15 million cases of chlamydial disease, 16 million cases of gonorrhea, and 30 million cases of trichomoniasis."Sexually transmitted infections and womenThe majority of HIV infections, risks, and other sexually transmitted infections in Sub-Saharan Africa disproportionately impact women. Women, particularly under the age of 30, account for more than half of new infections on the African continent, employing incidence rates that are often double that of their male counterparts. Not only do women contain more risk of infection, but the consequences of these diseases are often significantly worse for women, as they can affect reproductive health as well. Some consequences of bacterial STIs include "pelvic inflammatory disease, chronic pelvic pain, tubal infertility, pregnancy complications, fetal and neonatal death." HIV infection is less unbalanced in gender infections, but other STIs disproportionately affect women, "who bear 80 percent of the disability." Previously stated, women are also more susceptible to infection due to social stigma and gendered expectations. "Most women with STDs will not seek medical care at all, or will only present late for treatment, when complications have already developed, complications that have devastating physical, psychological, and social consequences, particularly for women and their children." Women of lower-income status are often the least likely subgroup to receive any sort of medical attention.More on LGBTQ+ healthIndividuals who identify as transgender often yield significantly higher rates of HIV in comparison to other subgroups. African politics and government are silent on LGBTQ+ issues in the political sphere, which translates in part to their accessibility and prioritization in healthcare | Sexual and reproductive health | Wikipedia | 493 | 2159778 | https://en.wikipedia.org/wiki/Sexual%20and%20reproductive%20health | Biology and health sciences | Fields of medicine | null |
"It is possible that the invisibility of transgender people in epidemiological data from Africa is related to the criminalization of same-sex behaviour in many countries," representative of how traditional attitudes shape one's ability to participate similarly in society. Further research conducted among transgender women in South Africa shows more "health disparities and poor access to appropriate mental, sexual and reproductive health services." Still, however, there is limited data concerning transgender individuals within African countries | Sexual and reproductive health | Wikipedia | 96 | 2159778 | https://en.wikipedia.org/wiki/Sexual%20and%20reproductive%20health | Biology and health sciences | Fields of medicine | null |
Individuals identifying as part of the LGBTQ+ community, in a study conducted by BMC International Health and Human Rights, resulted all in facing some sort of discrimination by healthcare providers based on their sexual orientation and/or gender identity. Violations took four distinct forms: availability, accessibility, acceptability, and quality. Facilities in South Africa lack services for specific LGBT concerns, providers refuse to care for patients identifying within the community, and if did, articulate moral disapproval. Finally, the lack of quality and knowledge about LGBTQ+ identities and health needs contributes to disproportionate negative harms, avoiding or delaying seeking healthcare with these implications.
The workplace and reproductive health
Reproductive health can be impacted by exposures in the workplace. Both women and men who work during their reproductive years can be exposed to a variety of chemical, physical, and psychosocial hazards at work that can impact their fertility. Many women continue to work while pregnant, thus increasing the likelihood that both mother and baby could be exposed.
Routes of exposure
Harmful substances can enter a woman's body through breathing in (inhalation), contact with the skin, or swallowing (ingestion). Pregnant workers and those planning to become pregnant should be especially concerned about exposure to reproductive hazards. Some chemicals (such as alcohol) can circulate in the mother's blood, pass through the placenta, and reach the developing fetus. Other hazardous agents can affect the overall health of the woman and reduce the delivery of nutrients to the fetus. Radiation can pass directly through the mother's body to harm her eggs or the fetus. Some drugs and chemicals can also pass through a mother's body into the nursing baby through the breast milk.
Reproductive hazards do not affect every woman or every pregnancy. Whether a woman or her baby is harmed depends on how much of the hazard they are exposed to, when they are exposed, how long they are exposed, how they are exposed, and personal factors like age, stage of menstrual cycle, stage of pregnancy or when exposure occurs. For example, exposure to a hazard could block ovulation and pregnancy only at specific times of the menstrual cycle. Exposure during the first 3 months of pregnancy might cause a birth defect or a miscarriage. Exposure during the last 6 months of pregnancy could slow the baby's growth, affect its brain development, or cause premature labor. | Sexual and reproductive health | Wikipedia | 487 | 2159778 | https://en.wikipedia.org/wiki/Sexual%20and%20reproductive%20health | Biology and health sciences | Fields of medicine | null |
Workplace substances that affect female workers and their pregnancies can also harm their families. Without knowing it, workers can bring home harmful substances that can affect the health of other family members—both adults and children. For example, lead brought home from the workplace on a worker's skin, hair, clothes, shoes, tool box, or car can cause lead poisoning in family members, especially young children.
Occupational reproductive hazards
A number of occupational hazards can impact reproductive health and subsequently reproductive outcomes including chemical, physical, and psychosocial hazards. Although more than 1,000 workplace chemicals have been shown to have reproductive effects on animals, most have not been studied in humans. In addition, most of the 4 million other chemical mixtures in commercial use remain untested.
Some reproductive hazards include:
Anesthetic gases
Antineoplastic (cancer treatment drugs)
Chemical disinfectants and sterilants
Certain ethylene glycol ethers such as 2-ethoxyethanol (2EE) and 2-methoxyethanol (2ME)
Carbon disulfide (CS2)
Epoxies and resins
Ethylene Oxide
Formaldehyde
Heat
Infectious agents
Lead and other heavy metals
Noise
Pesticides
Ionizing radiation
Non-ionizing radiation
Secondhand smoke
Smoke and by-products of burning
Solvents
Shift work and long working hours
Strenuous physical demands (e.g. prolonged standing, heavy lifting, bending)
Many chemicals are not evaluated for reproductive toxicity and occupational exposure limits are developed based on nonpregnant adults. Exposure levels considered safe for an adult may, or may not be safe for a fetus.
Reproductive health problems that might be caused by workplace exposures
Workplace hazards can lead to certain reproductive health problems, such as:
Reduced fertility or infertility
Erectile dysfunction
Menstrual cycle and ovulatory disorders
Women's health problems linked to sex hormone imbalance
Miscarriage
Stillbirth
Babies born too soon or too small
Birth defects
Child developmental disorders
Childhood cancers
Occupational hazards and female reproductive health
Some workplace hazards can affect reproductive health, the ability to become pregnant, and the health of unborn children. Most women can safely keep working in their job during their pregnancy. But some jobs involve exposures that are harmful to pregnant or breastfeeding women. Some female health problems that may be caused by workplace reproductive hazards include the following: | Sexual and reproductive health | Wikipedia | 481 | 2159778 | https://en.wikipedia.org/wiki/Sexual%20and%20reproductive%20health | Biology and health sciences | Fields of medicine | null |
Disruption of the menstrual cycle and hormone production
High levels of physical or emotional stress or exposure to chemicals such as pesticides, polychlorinated biphenyls (PCBs), organic solvents and carbon disulfide, may disrupt the balance between the brain, pituitary gland, and ovaries. This disruption can result in an imbalance of estrogen and progesterone, and lead to changes in menstrual cycle length and regularity and ovulation. Because these sex hormones have effects throughout a woman's body, severe or long-lasting hormone imbalances may affect a woman's overall health.
Hazards that can disrupt the menstrual cycle and/or sex hormone production include:
a variety of pesticides
carbon disulfide (CS2)
polychlorinated biphenyls (PCBs)
organic solvents
jet fuel
shift work
Infertility and subfertility
About 10% to 15% of all couples are infertile or have subfertility, which means that they are unable to conceive a child after 1 year of trying to become pregnant. Many factors can affect fertility, and these factors can affect one or both partners. Damage to the woman's eggs or the man's sperm, or a change in the hormones needed to regulate the normal menstrual cycle are just a few things that can cause problems with fertility. More common causes of infertility include:
Damage to the woman's eggs
Damage to the man's sperm
Infertility can be caused by change in the hormones needed to regulate the normal menstrual cycle and uterine growth. Hazards that can reduce fertility in women include:
cancer treatment drugs, including antineoplastic drugs
lead
ionizing radiation, including x-rays and gamma rays
nitrous oxide (N2O)
Miscarriages and stillbirths
About 1 in every 6 pregnancies ends in a miscarriage—the unplanned termination of a pregnancy. Miscarriages can occur very early in pregnancy, even before the woman knows she is pregnant. Miscarriages and stillbirths occur for many reasons, such as the following:
The egg or sperm may be damaged so that the egg cannot be fertilized or cannot survive after fertilization.
A problem may exist in the hormone system needed to maintain the pregnancy.
The fetus may not have developed normally.
Physical problems may exist with the uterus or cervix. | Sexual and reproductive health | Wikipedia | 508 | 2159778 | https://en.wikipedia.org/wiki/Sexual%20and%20reproductive%20health | Biology and health sciences | Fields of medicine | null |
Birth defects
A birth defect is a physical abnormality present at birth, though it may not be detected until later. About 2% to 3% of babies are born with a major birth defect. In most cases, the cause of the birth defect is unknown. The first 3 months of the pregnancy is a very sensitive time of development because the internal organs and limbs are formed during this period. Many women are not aware that they are pregnant during much of this critical period.
Low birth weight and premature birth
About 7% of babies born in the United States are born underweight or prematurely. Poor maternal nutrition, smoking, and alcohol use during pregnancy are believed to be responsible for most of these cases. Although better medical care has helped many underweight or premature babies to develop and grow normally, they are more likely than other babies to become ill or even die during their first year of life.
Developmental disorders
Sometimes the brain of the fetus does not develop normally, which leads to developmental delays or learning disabilities later in life. About 10% of children in the United States have some form of developmental disability. Such problems are often not noticeable at birth. They can be difficult to measure, may be temporary or permanent, and range from mild to severe. Developmental problems may appear as hyperactivity, short attention span, reduced learning ability, or (in severe cases) intellectual disability.
Other health problems
Even if a woman is not trying to become pregnant, her general health can be harmed by reproductive hazards that alter the production of sex hormones. Sex hormones have effects throughout a woman's body. Some workplace exposures can cause an imbalance of estrogen and progesterone levels in the blood. This disruption can increase vulnerability to:
Some cancers, such as endometrial or breast cancer
Osteoporosis
Heart disease
Tissue loss or weakening
Effects on the brain and spinal cord, including symptoms of menopause
Occupational hazards and male reproductive health
A number of workplace substances have been identified as reproductive hazards for men such as:
Lead
Dibromochloropropane
Carbaryl (sevin)
Toluenediamine and dinitrotoluene
Ethylene dibromide
Plastic production (styrene and acetone)
Ethylene glycol monoethyl ether
Welding
Perchloroethylene
Mercury vapor
Heat
Military radar
High levels of kepone
High levels of bromine vapor
High levels of radiation
Carbon disulfide
2,4-dichlorophenoxy acetic acid (2,4-D) | Sexual and reproductive health | Wikipedia | 509 | 2159778 | https://en.wikipedia.org/wiki/Sexual%20and%20reproductive%20health | Biology and health sciences | Fields of medicine | null |
Exposure to occupational hazards can impact:
Number of sperm. Some reproductive hazards can stop or slow the actual production of sperm. This means that there will be fewer sperm present to fertilize an egg; if no sperm are produced, the man is sterile. If the hazard prevents sperm from being made, sterility is permanent.
Sperm shape. Reproductive hazards may cause the shape of sperm cells to be different. These sperm often have trouble swimming or lack the ability to fertilize the egg.
Sperm transfer. Hazardous chemicals may collect in the epididymis, seminal vesicles, or prostate. These chemicals may kill the sperm, change the way in which they swim, or attach to the sperm and be carried to the egg or the unborn child.
Sexual performance. Changes in amounts of hormones can affect sexual performance. Some chemicals, like alcohol, may also affect the ability to achieve erections, whereas others may affect the sex drive. Several drugs (both legal and illegal) have effects on sexual performance, but little is known about the effects of workplace hazards.
Sperm chromosomes. Reproductive hazards can affect the chromosomes found in sperm. The sperm and egg each contribute 23 chromosomes at fertilization. The DNA stored in these chromosomes determines what someone will look like and their our bodies will function. Radiation or chemicals may cause changes or breaks in the DNA. If the sperm's DNA is damaged, it may not be able to fertilize an egg; or if it does fertilize an egg, it may affect the development of the fetus. Some cancer treatment drugs are known to cause such damage. However, little is known about the effects of workplace hazards on sperm chromosomes.
Pregnancy'''. If a damaged sperm does fertilize an egg, the egg might not develop properly, causing a miscarriage or a possible health problem in the baby. If a reproductive hazard is carried in the semen, the fetus might be exposed within the uterus, possibly leading to problems with the pregnancy or with the health of the baby after it is born. | Sexual and reproductive health | Wikipedia | 421 | 2159778 | https://en.wikipedia.org/wiki/Sexual%20and%20reproductive%20health | Biology and health sciences | Fields of medicine | null |
The snow pea is an edible-pod pea with flat pods and thin pod walls. It is eaten whole, with both the seeds and the pod, while still unripened.
Names
The common name snow pea seems to be a misnomer as the planting season of this pea is no earlier than that of other peas. Another common name, Chinese pea, is probably related to its prominence in Chinese dishes served in the West. It is called mangetout in the United Kingdom and Ireland (from the French for "eat-all" and pronounced monge-too; /mɒnʒtuː/).
Snow peas and snap peas both belong to Macrocarpon Group, a cultivar group based on the variety Pisum sativum var. macrocarpum Ser. named in 1825. It was described as having very compressed non-leathery edible pods in the original publication.
The scientific name Pisum sativum var. saccharatum Ser. is often misused for snow peas. The variety under this name was described as having sub-leathery and compressed-testes pods and the French name petit pois. The description is inconsistent with the appearance of snow peas, and therefore botanists have replaced this name with Pisum sativum var. macrocarpum. Austrian scientist and monk Gregor Mendel used peas which he called Pisum saccharatum in his famous experiments demonstrating the heritable nature of specific traits, and this Latin name might not refer to the same varieties identified with modern snow peas.
Composition
Nutrition
Uses
Culinary
Snow peas, along with sugar snap peas and unlike field and garden peas, are notable for having edible pods that lack inedible fiber (in the form of "parchment", a fibrous layer found in the inner pod rich in lignin) in the pod walls. Snow peas have the thinner walls of the two edible pod variants. Two recessive genes known as p and v are responsible for this trait. p is responsible for reducing the sclerenchymatous membrane on the inner pod wall, while v reduces pod wall thickness (n is a gene that thickens pod walls in snap peas).
Pea shoots () are the stems and leaves of the immature plant, used as a vegetable in Chinese cooking. They are commonly stir-fried with garlic and sometimes combined with crab or other shellfish. | Snow pea | Wikipedia | 482 | 11737869 | https://en.wikipedia.org/wiki/Snow%20pea | Biology and health sciences | Pulses | Plants |
Nitrogen fixers
As with most legumes, snow peas host beneficial bacteria, rhizobia, in their root nodules, which fix nitrogen in the soil—this is called a mutualistic relationship—and are therefore a useful companion plant, especially useful to grow intercropped with green, leafy vegetables that benefit from high nitrogen content in their soil.
Cultivation
Snow peas can be grown in open fields during cool seasons and can thus be cultivated during winter and spring seasons.
Storage
Storage of the pea with films of polymethylpentene at a temperature of and controlled atmosphere with a concentration of oxygen and carbon dioxide of 5 kPa augments the shelf life, internal and external characteristics of the plant.
Gallery | Snow pea | Wikipedia | 144 | 11737869 | https://en.wikipedia.org/wiki/Snow%20pea | Biology and health sciences | Pulses | Plants |
Peak demand on an electrical grid is the highest electrical power demand that has occurred over a specified time period (Gönen 2008). Peak demand is typically characterized as annual, daily or seasonal and has the unit of power.
Peak demand, peak load or on-peak are terms used in energy demand management describing a period in which electrical power is expected to be provided for a sustained period at a significantly higher than average supply level. Peak demand fluctuations may occur on daily, monthly, seasonal and yearly cycles. For an electric utility company, the actual point of peak demand is a single half-hour or hourly period which represents the highest point of customer consumption of electricity. At this time there is a combination of office, domestic demand and at some times of the year, the fall of darkness.
Some utilities will charge customers based on their individual peak demand. The highest demand during each month or even a single 15 to 30 minute period of highest use in the previous year may be used to calculate charges. The renewable energy transition will include considerations for peak demand.
Economic growth of the state is inversely associated with peak load.
Demand Tariff
Electricity network is built to deal with the highest possible peak demand otherwise blackout may happen. In Australia, demand tariff has three components: peak demand charge, energy charge and daily connection charge. For example, for large customers (commercial, industrial or mixed of commercial/residential), the peak demand charge is based on the highest 30 minutes electricity consumption in a month; the energy charge is based on a month electricity consumption. This type of demand tariff is gradually introduced to residential households and will be rolled out by 2020 in Queensland Australia. How to manage electricity bills under demand tariff can be challenging. The key solutions involve improving building efficiency and managing the operational settings of large power appliances.
Time of Peak Demand
Peak Demand depends on the demography, the economy, the weather, the climate, the season, the day of the week and other factors. In industrialised regions of China or Germany, the peak demands mostly occur in day time. However, in more service based economy such as Australia, the daily peak demands often occur in the late afternoon to early evening time (e.g. 4pm to 8pm). Residential and commercial electricity demand contributes a lot to this type of network peak demand. | Peak demand | Wikipedia | 462 | 11738757 | https://en.wikipedia.org/wiki/Peak%20demand | Technology | Concepts | null |
Off-peak
Peak demand is considered to be the opposite to off-peak hours when power demand is usually low. There are off-peak time-of-use rates. Sometimes, there are 3 time-of-use zones: peak, shoulder and offpeak. Shoulder is often the time between peak and offpeak in weekdays. Weekends are often just peak and offpeak in terms of managing electricity loads for the network.
Response
Peak demand may exceed the maximum supply levels that the electrical power industry can generate, resulting in power outages and load shedding. This often occurs during heat waves when use of air conditioners and powered fans raises the rate of energy consumption significantly. During a shortage authorities may request the public to curtail their energy use and shift it to a non-peak period.
Power stations
Power stations specifically constructed for providing power to electrical grids for peak demand are called peaking power plants or 'peakers'. In general, Natural gas fueled power stations can be fired up rapidly and are therefore often utilized at peak demand times. Combined cycle power plants can frequently provide power for peak demand, as well as run efficiently for baseload power.
Hydroelectric power and pumped storage type dams such as Carters Dam in the U.S. state of Georgia help to meet peak demand as well.
The chances that a wind farm will be unable to meet peak demand are greater than for a fossil-fueled power station, due to the ability to store liquid fuels for use during peak demand.
Solar power's peak output often naturally coincides with daytime peaks of usage due to air conditioning. | Peak demand | Wikipedia | 322 | 11738757 | https://en.wikipedia.org/wiki/Peak%20demand | Technology | Concepts | null |
Planetary nebula luminosity function (PNLF) is a secondary distance indicator used in astronomy. It makes use of the [O III] λ5007 forbidden line found in all planetary nebula (PNe) which are members of the old stellar populations (Population II).
It can be used to determine distances to both spiral and elliptical galaxies despite their completely different stellar populations and is part of the Extragalactic Distance Scale.
Procedure
The distance estimate to a galaxy using the PNLF requires discovery of such an object in the target galaxy that is visible at λ5007 but not when the entire spectrum is considered. These points are candidate PNe, however, there are three other types of objects that would also exhibit such an emission line that must be filtered out: HII regions, supernova remnants, and Lyα galaxies. After the PNe are determined, to estimate a distance one must measure their monochromatic [O III] λ5007 luminosity. What remains is a statistical sample of
PNe. The observed luminosity function is then fitted to some standard law.
Finally, one must estimate the foreground interstellar extinction. The two sources of extinction, are from within the Milky Way and the internal extinction of the target galaxy. The first is well known and can be taken from sources such as reddening maps computed from H I measurements and galaxy counts or from IRAS and DIRBE satellite experiments. The later type of extinction, occurs only in target galaxies which are either late type spiral or irregular. However, this extinction is difficult to measure. In the Milky Way, the scale height of PNe is much bigger than that of the dust. Observational data and models support that this holds true for other galaxies, that the bright edge of the PNLF is primarily due to PNe in front of the dust layer. The data and models support a less than 0.05 apparent magnitude internal extinction of a galaxy's PNe. | Planetary nebula luminosity function | Wikipedia | 397 | 13256745 | https://en.wikipedia.org/wiki/Planetary%20nebula%20luminosity%20function | Physical sciences | Basics | Astronomy |
Physics behind process
The PNLF method is unbiased by metallicity. This is because oxygen is a primary nebular coolant; any drop in its concentration raises the plasma's electron temperature and raises the amount of collisional excitations per ion. This compensates for having a smaller number of emitting ions in the PNe resulting in little change in the λ5007 emissions . Consequently, a reduction in oxygen density only lowers the emergent [O III] λ5007 emission line intensity by approximately the square root of the difference in abundance. At the same time, the PNe's core responds to metallicity the opposite way. In the case where the metallicity of the progenitor star is smaller, the PNe's central star will be a bit more massive and its illuminating ultraviolet flux will be a bit greater. This added energy almost precisely accounts for the decreased emissions of the PNe. Consequently, the total [O III] λ5007 luminosity that is produced by a PNe is practically
uncorrelated to metallicity. This beneficial negation is in agreement with more precise models of PNe evolution. Only in extremely metal-poor PNe does the brightness of the PNLF cutoff dim by more than a small percentage.
The relative independence of the PNLF cutoff with respect to population age is harder to understand. The [O III] λ5007 flux of a PNe directly correlates to the brightness of its central star. Further, the brightness of its central star directly correlates to its mass and the central star's mass directly varies in relation to its progenitor's mass. However, by observation, it is demonstrated that reduced brightness does not happen. | Planetary nebula luminosity function | Wikipedia | 355 | 13256745 | https://en.wikipedia.org/wiki/Planetary%20nebula%20luminosity%20function | Physical sciences | Basics | Astronomy |
Utahraptor (meaning "Utah's predator") is a genus of large dromaeosaurid (a group of feathered carnivorous theropods) dinosaur that lived during the Early Cretaceous period from around 135 to 130 million years ago in what is now the United States. The genus was described in 1993 by American paleontologist James Kirkland and colleagues with the type species Utahraptor ostrommaysi, based on fossils that had been unearthed earlier from the Cedar Mountain Formation of Utah. Later, many additional specimens were described including those from the skull and postcranium in addition to those of younger individuals.
The genus contains a single species, Utahraptor ostrommaysi. It is the largest-known member of the family Dromaeosauridae, measuring about long and typically weighing up to . As a heavily built, ground-dwelling, bipedal carnivore, its large size and variety of unique features have earned it attention in both pop culture and the scientific community. The jaws of Utahraptor were lined with small, serrated teeth that were used in conjunction with a large "killing claw" on its second toe to dispatch its prey. Its skull was boxy and elongated, akin to other dromaeosaurids like Dromaeosaurus and Velociraptor.
Being a carnivore, Utahraptor was adapted to hunt the other animals of the Cedar Mountain Formation ecosystem such as ankylosaurs and iguanodonts. Evidence from the leg physiology supports the idea of Utahraptor being an ambush predator, in contrast to other dromaeosaurs that were pursuit predators. Fossil remains of several individuals of various ages have been found together, suggesting that Utahraptor was gregarious (social) and practiced degrees of post nestling care.
Discovery and naming | Utahraptor | Wikipedia | 383 | 569684 | https://en.wikipedia.org/wiki/Utahraptor | Biology and health sciences | Theropods | Animals |
The first specimens of Utahraptor were found in 1975 by Jim Jensen in the Dalton Wells Quarry of Utah, near the town of Moab, but did not receive much attention. After a find of a large claw by Carl Limone in October 1991, James Kirkland, Robert Gaston and Donald Burge uncovered further remains of Utahraptor in 1991 in the Gaston Quarry in Grand County, Utah, within the Yellow Cat and Poison Strip members of the Cedar Mountain Formation. The holotype of Utahraptor, CEUM 184v.86, consists of a second pedal ungual, with potentially assigned elements from other specimens: pedal ungual CEUM 184v.294, tibia CEUM 184v.260 and premaxilla CEUM 184v.400. The holotype is housed in the paleontology collections of the Prehistoric Museum at Utah State University Eastern. Brigham Young University, the depository of Jensen's finds, currently houses the largest collection of Utahraptor fossils.
The type species, Utahraptor ostrommaysi, was named by Kirkland, Gaston and Burge in June 1993. The genus name Utahraptor is in reference to Utah, where the remains were found. The specific name, ostrommaysi, is in honor to John Ostrom for his investigations on Deinonychus and its relationships to birds, as well as Chris Mays, who helped in the research of Utahraptor by founding Dinamation. From his description, Kirkland stated the meaning of genus name to be "Utah's predator," but the Latin word raptor translates to 'robber' or 'plunderer', not 'predator'. Earlier, it had been intended to name the species "U. spielbergi" after film director Steven Spielberg, in exchange for him funding paleontological research, but no agreement could be reached on the amount of financial assistance. | Utahraptor | Wikipedia | 394 | 569684 | https://en.wikipedia.org/wiki/Utahraptor | Biology and health sciences | Theropods | Animals |
In 2000, the specific name was emended by George Olshevsky to the plural genitive ostrommaysorum. However, Thiago Vernaschi V. Costa and Normand David in 2019 criticized the use of the species name U. ostrommaysorum, since it has no clear justification or explanation. Although this spelling has been largely used by other authors, the genus Utahraptor was originally coined with the type species U. ostrommaysi and, given that the International Code of Zoological Nomenclature offers no provision for forming a genitive form from two persons with different names, Costa and David conclude that the original spelling ostrommaysi has to be regarded as an arbitrary combination of letters and not a correctly formed genitive form. Under this reasoning, ostrommaysorum has no valid use and the original spelling ostrommaysi does not need to be emended. Other alternative and also invalid spellings were used in scientific literature, such as ostromaysi, ostromaysorum, ostromayssorum, ostromayorum and ostrommaysori.
Some elements were wrongly referred to the genus. The lacrimal bone of the specimen CEUM 184v.83 turned out to be a postorbital from the ankylosaur Gastonia. Britt et al. also suggested that the previously identified manual unguals of the specimens M184v.294, BYU 9438 and BYU 13068 are indeed pedal unguals. This suggestion was confirmed by Senter in 2007.
Description
Utahraptor was one of, if not the largest and heaviest of all dromaeosaurids, with the largest assigned specimen BYUVP 15465 having a femoral length of .
Utahraptor is estimated to have reached in length and somewhat less than , comparable in weight to a polar bear. Some authors estimated that it weighed up to . In 2024, the body mass of BYUVP 2536 and BYUVP 1833 were estimated around respectively, though BYUVP 7510-18078 was estimated to have weighed . | Utahraptor | Wikipedia | 428 | 569684 | https://en.wikipedia.org/wiki/Utahraptor | Biology and health sciences | Theropods | Animals |
Although feathers have never been found in association with Utahraptor specimens, there is strong phylogenetic evidence suggesting that all dromaeosaurids had them. The feathered genus Microraptor is one of the oldest-known dromaeosaurids and is phylogenetically more primitive than Utahraptor. Since Microraptor and other dromaeosaurids possessed feathers, it is reasonable to assume that this trait was present in all of Dromaeosauridae. Feathers were very unlikely to have evolved more than once, so assuming that any given dromaeosaurid, such as Utahraptor, lacked feathers would require positive evidence that they did not have them. So far, there is nothing to suggest that feathers were lost in larger, more derived species of dromaeosaurs. The presence of quill knobs in Dakotaraptor evidenced that even larger dromaeosaurids had feathers.
According to Kirkland et al. in 1993, Utahraptor can be recognized by a few special autapomorphies. The claws on its hand are more specialized as cutting blades than in other dromaeosaurids. It has a lacrimal bone with distinctly parallel mesial and outer sides that gives it an elongate subrectangular appearance in top view and it has a base of the nasal opening on the premaxilla parallel to the premaxillary tooth row. In the revised diagnosis conducted by Turner et al. in 2012, Utahraptor differs from other dromaeosaurids in having an elongate nasal process of the premaxilla, a distal end of metatarsal III that is smooth, not ginglymoid, an L-shaped quadratojugal without a posterior process, the presence of a well-developed notch between the lesser trochanter and greater trochanter, and dorsal vertebrae that lack pleurocoels. Like other dromaeosaurids, Utahraptor had a large curved claw on the second toe of each foot. The second pedal ungual is preserved with a outside curve length and is estimated to reach in restoration. | Utahraptor | Wikipedia | 450 | 569684 | https://en.wikipedia.org/wiki/Utahraptor | Biology and health sciences | Theropods | Animals |
Classification
Utahraptor is a member of the family Dromaeosauridae, a clade of theropod dinosaurs commonly known as "raptors". Utahraptor is the largest known genus in the family and belongs to the same clade of other notable dinosaurs such as Velociraptor, Deinonychus, or Dromaeosaurus. It is classified in the subfamily Dromaeosaurinae, which is found in the clade Eudromaeosauria.
In 2015, Utahraptor was found to be closely related to the smaller Dromaeosaurus and the giant Mongolian and North American dromaeosaurid genera Achillobator and Dakotaraptor:
The cladogram below is the result of a cladistic analysis conducted by Cau et al. in 2017.
Paleobiology
Predatory behavior
Kirkland et al. noted that given the huge size of Utahraptor, it was not as fast as Deinonychus and Velociraptor; instead, it would have had a similar speed to the contemporary iguanodonts, and was faster than sauropods. Additionally, the thickness of the tibia indicates that the animal possessed a significant leg force in order to kill prey. It was also suggested that lighter dromaeosaurids such as Velociraptor and Deinonychus relied on their hand claws to handle prey and retain balance while kicking it; in contrast to this, the heavily built Utahraptor may have been able to deliver kicks without the risk of losing balance, freeing the hands and using them to dispatch prey.
According to Gregory S. Paul, Utahraptor was not particularly fast and would have been an ambush hunter that preyed on large dinosaurs such as the contemporary iguanodonts and therizinosaurs. Its robust build and large sickle claw indicate it was well suited to hunting such prey. Like other dromaeosaurine dromaeosaurids, it may have also relied heavily on its jaws to dispatch prey—more so than other types of dromaeosaurids, such as velociraptorines. | Utahraptor | Wikipedia | 444 | 569684 | https://en.wikipedia.org/wiki/Utahraptor | Biology and health sciences | Theropods | Animals |
Social behavior
In 2001, Kirkland et al. pursued a graduate student's discovery of a bone protruding from a 9-ton fossil block of sandstone in eastern Utah. It was determined to contain the bones of at least seven individuals, including an adult measuring about , four juveniles, and a hatchling about long. Also fossilized with the Utahraptor pack are the remains of at least one possible iguanodont. Kirkland speculated that the Utahraptor pack attempted to scavenge carrion or attack helpless prey mired in quicksand, and were themselves mired in the attempt to feed on the herbivore. Similar sites such as the Cleveland-Lloyd Quarry and California's La Brea Tar Pits house such predator traps. Examination of the fossils are ongoing after a decade of excavation, but if Kirkland is correct, it may be one of the best-preserved predator traps ever discovered. The fossils may further reveal aspects into the behavior of Utahraptor, such as whether it might have hunted in groups like Deinonychus was believed to have done. Whether all the Utahraptor individuals were mired simultaneously or were drawn in, one-by-one is unclear. Further examination of the block suggests that the number of Utahraptor remains may be double the amount previously assumed.
While dinosaur behavior can only be theorized, it was later discovered in 2020 that Deinonychus may not have practiced mammal-like pack hunting, based on differing dietary preferences in adults and juveniles. Despite this, the authors stated that gregariousness was still possible for Deinonychus and the discovery of Utahraptor in the mud-trap implies it exhibited a degree of post nestling care and gregariousness. | Utahraptor | Wikipedia | 358 | 569684 | https://en.wikipedia.org/wiki/Utahraptor | Biology and health sciences | Theropods | Animals |
Paleoenvironment
Utahraptor lived in the lower part of the Cedar Mountain Formation, a bed known as the Yellow Cat Member. According to the authors of its description, Utahraptor had an important ecological role as a major carnivore of the paleofauna of the present-day Arches region during the Early Cretaceous, and could probably attack prey larger than itself. Group hunting of individuals of at least and , if proven, could have killed prey of a weight of . Additionally, sauropods ranging around may have been an important part of its diet. The paleontologist Thomas R. Holtz estimated that Utahraptor existed between 130 million and 125 million years ago. In multiple occasions, the Yellow Cat Member has been dated to Barremian-Aptian ages. Sames and Schudack (2010) proposed a reassignment of the estimated age, compromising Berriasian to Valanginian stages; however, this interpretation was not followed by most authors. Using advanced methods of radiometric and palynological dating, Joeckel et al. (2019) concluded that the Yellow Cat Member is indeed older than previous estimations. The deposition occurred between 139 ± 1.3 million to 134.6 ± 1.7 million years ago, or, Berriasian to Late Valanginian stages. Based on the presence of new palynoflora, Middle Berriasian–Early Hauterivian ages were provisionally assigned. However, the Yellow Cat Member is divided into distinct "lower" and "upper" layers, and Utahraptor fossils are only currently known within the upper Yellow Cat Member.
Utahraptor was unearthed from the Yellow Cat Member, which during the Berriasian to Late Valanginian was a semiarid area with floodplain prairies, riverine forests, and open woodlands predominated by conifers (Pinophyta), ferns (Polypodiopsida), hornworts (Anthocerotophyta) and other vascular plants. During the description of Mierasaurus, it was interpreted that there was also a waterlogged bog-like environment. There is believed to have been a short wet season. This is supported by the presence of charred spores and other carbonized plant debris in the pollen maceral that indicate the occurrence of ancient wildfires ignited during periods of low precipitation. | Utahraptor | Wikipedia | 489 | 569684 | https://en.wikipedia.org/wiki/Utahraptor | Biology and health sciences | Theropods | Animals |
Paleofauna that were contemporaneous with the dromaeosaurid in the upper Yellow Cat Member included numerous dinosaurs, such as the medium-sized iguanodonts Hippodraco and Cedrorestes, the smaller theropods Martharaptor and Nedcolbertia, the nodosaurid Gastonia, and the sauropods Cedarosaurus and Moabosaurus. The only known mammal from the Upper Yellow Cat Member is Cifelliodon.
Other non-dinosaur or avian taxa known from the Member include the fish Ceratodus and Semionotus, the turtles Glyptops and Trinitichelys, Aquatilavipes (fossilized bird tracks), the rhynchocephalian Toxolophosaurus, and the indeterminate remains of hybodontid and polyacrodontid sharks.
Additional paleofauna was recovered, most of it being unnamed and/or indeterminate, including an isolated mesoeucrocodylian skull that measures in length. A neochoristodere unearthed from the Upper Yellow Cat Member, represented by a partial left femur, shows that aquatic paleofauna was present and diverse during the Early Cretaceous of the Cedar Mountain Formation. A large sail-backed iguanodont represented by large vertebrae and fragmentary remains, and an indeterminate eudromaeosaur known from a caudal vertebra and fragmented tail (UMNH VP 20209) were also present.
Cultural significance
Raptor Red was published in 1995, and features the fictionalized story of a female Utahraptor. Written by paleontologist Robert T. Bakker, it was positively regarded by mainstream reviewers, though updates to the science have rendered some of the story line facts presented untrue and the paleontology community was critical of fossil record inaccuracies. Bakker's anthropomorphosis of the titular Red was particularly praised. | Utahraptor | Wikipedia | 408 | 569684 | https://en.wikipedia.org/wiki/Utahraptor | Biology and health sciences | Theropods | Animals |
In 2018, it was proposed by a 10-year-old elementary school student, Kenyon Roberts, that Utahraptor be the Utah state dinosaur, an act that was approved by the Senate. Initially Utahraptor would have replaced another dinosaur, Allosaurus, as the state's official fossil, but it was decided that Utahraptor would be another symbol of the state. In 2021, Steve Eliason successfully created a proposal for Utahraptor State Park where the block was discovered, proposed by the same Utah student, Kenyon Roberts. It was approved by the state House. | Utahraptor | Wikipedia | 122 | 569684 | https://en.wikipedia.org/wiki/Utahraptor | Biology and health sciences | Theropods | Animals |
A semi-arid climate, semi-desert climate, or steppe climate is a dry climate sub-type. It is located on regions that receive precipitation below potential evapotranspiration, but not as low as a desert climate. There are different kinds of semi-arid climates, depending on variables such as temperature, and they give rise to different biomes.
Defining attributes of semi-arid climates
A more precise definition is given by the Köppen climate classification, which treats steppe climates (BSh and BSk) as intermediates between desert climates (BW) and humid climates (A, C, D) in ecological characteristics and agricultural potential. Semi-arid climates tend to support short, thorny or scrubby vegetation and are usually dominated by either grasses or shrubs as they usually cannot support forests.
To determine if a location has a semi-arid climate, the precipitation threshold must first be determined. The method used to find the precipitation threshold (in millimeters):
multiply by 20 the average annual temperature in degrees Celsius and then
add 280 if at least 70% of the total precipitation falls in the summer half of the year (April–September in the northern hemisphere, October–March in the southern hemisphere)
add 140 if 30–70% of the total precipitation falls in the summer half of the year
add nothing if less than 30% of the total precipitation falls in the summer half of the year
If the area's annual precipitation in millimeters is less than the threshold but more than half or 50% the threshold, it is classified as a BS (steppe, semi-desert, or semi-arid climate).
Furthermore, to delineate hot semi-arid climates from cold semi-arid climates, a mean annual temperature of is used as an isotherm. A location with a BS-type climate is classified as hot semi-arid (BSh) if its mean temperature is above this isotherm, and cold semi-arid (BSk) if not.
Hot semi-arid climates
Hot semi-arid climates (type "BSh") tend to be located from the high teens to mid-30s latitudes of the tropics and subtropics, typically in proximity to regions with a tropical savanna climate or a humid subtropical climate. These climates tend to have hot, or sometimes extremely hot, summers and warm to cool winters, with some to minimal precipitation. Hot semi-arid climates are most commonly found around the fringes of subtropical deserts. | Semi-arid climate | Wikipedia | 504 | 569881 | https://en.wikipedia.org/wiki/Semi-arid%20climate | Physical sciences | Climates | Earth science |
Hot semi-arid climates are most commonly found in Africa, Australia, and South Asia. In Australia, a large portion of the Outback surrounding the central desert regions lies within the hot semi-arid climate region. In South Asia, both India and parts of Pakistan experience the seasonal effects of monsoons and feature short but well-defined wet seasons, but are not sufficiently wet overall to qualify as either a tropical savanna or a humid subtropical climate.
Hot semi-arid climates can be also found in parts of North America, such as most of northern Mexico, the ABC Islands, the rain shadows of Hispaniola's mountain ranges in the Dominican Republic and Haiti, parts of the Southwestern United States including California's Central Valley, and sections of South America such as the sertão, the Gran Chaco, and the poleward side of the arid deserts, where they typically feature a Mediterranean precipitation pattern, with generally rainless summers and wetter winters. They are also found in few areas of Europe surrounding the Mediterranean Basin. In Europe, BSh climates are predominantly found in southeastern Spain. It can also be found primarily in parts of south Greece but also in marginal areas of Thessaloniki and Chalkidiki in north Greece, most of Formentera, marginal areas of Ibiza and marginal areas of Italy in Sicily, Sardinia and Lampedusa.
Cold semi-arid climates
Cold semi-arid climates (type "BSk") tend to be located in elevated portions of temperate zones generally from the mid-30s to low 50s latitudes, typically bordering a humid continental climate or a Mediterranean climate. They are also typically found in continental interiors some distance from large bodies of water. Cold semi-arid climates usually feature warm to hot dry summers, though their summers are typically not quite as hot as those of hot semi-arid climates. Unlike hot semi-arid climates, areas with cold semi-arid climates tend to have cold and possibly freezing winters. These areas usually see some snowfall during the winter, though snowfall is much lower than at locations at similar latitudes with more humid climates. | Semi-arid climate | Wikipedia | 418 | 569881 | https://en.wikipedia.org/wiki/Semi-arid%20climate | Physical sciences | Climates | Earth science |
Areas featuring cold semi-arid climates tend to have higher elevations than areas with hot semi-arid climates, and tend to feature major temperature swings between day and night, sometimes by as much as 20 °C (36 °F) or more. These large diurnal temperature variations are seldom seen in hot semi-arid climates. Cold semi-arid climates at higher latitudes tend to have dry winters and wetter summers, while cold semi-arid climates at lower latitudes tend to have precipitation patterns more akin to Mediterranean climates, with dry summers, relatively wet winters, and even wetter springs and autumns.
Cold semi-arid climates are most commonly found in central Asia and the western US, as well as the Middle East and other parts of Asia. However, they can also be found in Northern Africa, South Africa, sections of South America, sections of interior southern Australia (e.g. Kalgoorlie and Mildura) and inland Spain.
Charts of selected cities
Hot semi-arid
Cold semi-arid | Semi-arid climate | Wikipedia | 204 | 569881 | https://en.wikipedia.org/wiki/Semi-arid%20climate | Physical sciences | Climates | Earth science |
The Siberian crane (Leucogeranus leucogeranus), also known as the Siberian white crane or the snow crane, is a bird of the family Gruidae, the cranes. They are distinctive among the cranes: adults are nearly all snowy white, except for their black primary feathers that are visible in flight, and with two breeding populations in the Arctic tundra of western and eastern Russia. The eastern populations migrate during winter to China, while the western population winters in Iran and (formerly) in Bharatpur, India.
Among the cranes, they make the longest distance migrations. Their populations, particularly those in the western range, have declined drastically in the 20th century due to hunting along their migration routes and habitat degradation. The world population was estimated in 2010 at about 3,200 birds, mostly belonging to the eastern population with about 93% of them wintering in the Poyang Lake basin in China, a habitat that may be altered by the Three Gorges Dam.
Taxonomy and systematics
The Siberian crane was formally described by Peter Simon Pallas in 1773 and given the binomial name Grus leucogeranus. The specific epithet is derived from the classical Greek words leukos for "white" and geranos for a "crane". Ustad Mansur, a 17th-century court artist and singer of Jahangir, had illustrated a Siberian crane about 100 years earlier. The genus Megalornis was used for the cranes by George Robert Gray and this species was included in it, while Richard Bowdler Sharpe suggested a separation from Grus and used the genus Sarcogeranus. The Siberian crane lacks the complex tracheal coils found in most other cranes but shares this feature with the wattled crane. The unison call differed from that of most cranes and some authors suggested that the Siberian crane belonged in the genus Bugeranus along with the wattled crane. Comparisons of the DNA sequences of cytochrome-b however suggest that the Siberian crane is basal among the Gruinae and the wattled crane is retained as the sole species in the genus Bugeranus and placed as a sister to the Anthropoides cranes. | Siberian crane | Wikipedia | 440 | 570029 | https://en.wikipedia.org/wiki/Siberian%20crane | Biology and health sciences | Gruiformes | Animals |
A molecular phylogenetic study published in 2010 found that the genus Grus, as then defined, was polyphyletic. In the resulting rearrangement to create monophyletic genera, the Siberian crane was moved to the resurrected genus Leucogeranus. The genus Leucogeranus had been introduced by the French biologist Charles Lucien Bonaparte in 1855.
Description
Adults of both sexes have a pure white plumage except for the black primaries, alula and primary coverts. The fore-crown, face and side of head is bare and brick red, the bill is dark and the legs are pinkish. The iris is yellowish. Juveniles are feathered on the face and the plumage is dingy brown. There are no elongated tertial feathers as in some other crane species. During breeding season, both the male and female cranes are often seen with mud streaking their feathers; they may intentionally smear mud on their feathers, which has been hypothesized to aid camouflage on the nest. The call is very different from the trumpeting of most cranes and is a goose-like high pitched whistling toyoya. This is a fairly large species of crane, typically weighing and standing about tall. The wingspan is reportedly from and length is . Males are on average larger than females. The average weight of adults in one study was while juvenile birds were slightly heavier on average at . There is a single record of an outsized male of this species weighing . Usually, this crane is usually slightly smaller in weight and height than some other cranes, particularly the sarus crane, wattled crane and red-crowned crane. | Siberian crane | Wikipedia | 325 | 570029 | https://en.wikipedia.org/wiki/Siberian%20crane | Biology and health sciences | Gruiformes | Animals |
Distribution and habitat
The breeding area of the Siberian crane formerly extended between the Urals and Ob river south to the Ishim and Tobol rivers and east to the Kolyma region. The populations declined with changes in landuse, the draining of wetlands for agricultural expansion and hunting on their migration routes. The breeding areas in modern times are restricted to two widely disjunct regions. The western area in the river basins of the Ob, Konda and Sossva and to the east a much larger population in Yakutia between the Yana and the Alazeya rivers. Like most cranes, the Siberian crane inhabits shallow marshlands and wetlands and will often forage in deeper water than other cranes. They show very high site fidelity for both their wintering and breeding areas, making use of the same sites year after year. The western population winters in Iran and some individuals formerly wintered in India south to Nagpur and east to Bihar. The eastern populations winter mainly in the Poyang Lake area in China.
Behaviour and ecology
Siberian cranes are widely dispersed in their breeding areas and are highly territorial. They maintain feeding territories in winter but may form small and loose flocks, and gather closer at their winter roosts. They are very diurnal, feeding almost all throughout the day. When feeding on submerged vegetation, they often immerse their heads entirely underwater. When calling, the birds stretch their neck forward. The contexts of several calls have been identified and several of these vary with sex. Individual variation is very slight and most calls have a dominant frequency of about 1.4 kHz. The unison calls, duets between paired males and female however are more distinctive with marked differences across pairs. The female produces a higher pitched call which is the "loo" in the duetted "doodle-loo" call. Pairs will walk around other pairs to threaten them and drive them away from their territory. In captivity, one individual was recorded to have lived for nearly 62 years while another lived for 83 years. | Siberian crane | Wikipedia | 407 | 570029 | https://en.wikipedia.org/wiki/Siberian%20crane | Biology and health sciences | Gruiformes | Animals |
Feeding
These cranes are omnivorous with a tendency to plant matter. In the summer grounds they feed on a range of plants including the roots of hellebore (Veratrum misae), seeds of Empetrum nigrum as well as small rodents like lemmings and voles, earthworms, and fish. They were earlier thought to be predominantly fish eating on the basis of the serrated edge of their bill, but later studies suggest that they take animal prey mainly when the vegetation is covered by snow. They also swallow pebbles and grit to aid in crushing food in their crop. In their wintering grounds in China, they have been noted to feed to a large extent on the submerged leaves of Vallisneria spiralis. Specimens wintering in India have been found to have mainly aquatic plants in their stomachs. They are however noted to pick up beetles and bird's eggs in captivity.
Breeding
Siberian cranes return to the Arctic tundra around the end of April and beginning of May. The nest is usually on the edge of lake in boggy ground and is usually surrounded by water. Most eggs are laid in the first week of June when the tundra is snow free. The usual clutch is two eggs, which are incubated by the female after the second egg is laid, with the male standing guard nearby. The eggs hatch in about 27 to 29 days. The young birds fledge in about 80 days. Usually only a single chick survives due to aggression between young birds. The population increase per year is less than 10%, the lowest recruitment rate among cranes. Their success in breeding may further be hampered by disturbance from reindeer and sometimes dogs that accompany reindeer herders. Captive breeding was achieved by the International Crane Foundation at Baraboo after numerous failed attempts. Males often killed their mates and captive breeding was achieved by artificial insemination and the hatching of eggs by other crane species such as the sandhill and using floodlights to simulate the longer daylengths of the Arctic summer. | Siberian crane | Wikipedia | 407 | 570029 | https://en.wikipedia.org/wiki/Siberian%20crane | Biology and health sciences | Gruiformes | Animals |
Migration
This species breeds in two disjunct regions in the arctic tundra of Russia; the western population along the Ob, Yakutia, and western Siberia. It is a long distance migrant and among the cranes, makes one of the longest migrations. The eastern population winters on the Yangtze River and Lake Poyang in China, and the western population in Fereydoon Kenar in Iran. The central population, which once wintered in Keoladeo National Park, Bharatpur, is extinct.
Status and conservation
The conservation status of the Siberian crane is very serious. In 2008, the decreasing world population was estimated to be around 3500–4000 individuals, nearly all of them belonging to the eastern breeding population. Of the 15 crane species, this is the only regarded as critically endangered, the highest threatened category by the IUCN (the whooping crane of North America has a smaller but rising population that is better protected, giving the species a status of endangered.) The western population of the Siberian crane had dwindled to four in 2002 and subsequently it was thought to be extirpated, but a single individual, named "Omid", has wintered in Iran since 2006–2007. The wintering site at Poyang in China holds an estimated 98% of the population and is threatened by hydrological changes caused by the Three Gorges Dam and other water development projects.
Historical records from India suggest a wider winter distribution in the past including records from Gujarat, near New Delhi and even as far east as Bihar. In the 19th century, larger numbers of birds were noted to visit India. They were sought after by hunters and specimen collectors. In 1974, as many as 75 birds wintered in Bharatpur, but this population declined to a single pair in 1992 and the last bird was seen in 2002. An individual that escaped from a private menagerie was shot in the Outer Hebrides in 1891. The western population may even have wintered as far west as Egypt along the Nile. | Siberian crane | Wikipedia | 409 | 570029 | https://en.wikipedia.org/wiki/Siberian%20crane | Biology and health sciences | Gruiformes | Animals |
Satellite telemetry was used to track the migration of a flock that wintered in Iran. They were noted to rest on the eastern end of the Volga Delta. Satellite telemetry was also used to track the migration of the eastern population in the mid-1990s, leading to the discovery of new resting areas along the species' flyway in eastern Russia and China. The Siberian crane is one of the species to which the Agreement on the Conservation of African-Eurasian Migratory Waterbirds (AEWA) applies and is subject of the Memorandum of Understanding concerning Conservation Measures for the Siberian Crane concluded under the Bonn Convention.
Significance in human culture
For the Yakuts and Yukaghirs, the white crane is a sacred bird associated with sun, spring and kind celestial spirits ajyy. In yakut epics Olonkho shamans and shamanesses transform into white cranes. | Siberian crane | Wikipedia | 177 | 570029 | https://en.wikipedia.org/wiki/Siberian%20crane | Biology and health sciences | Gruiformes | Animals |
Action at a distance is the concept in physics that an object's motion can be affected by another object without the two being in physical contact; that is, it is the concept of the non-local interaction of objects that are separated in space. Coulomb's law and Newton's law of universal gravitation are based on action at a distance.
Historically, action at a distance was the earliest scientific model for gravity and electricity and it continues to be useful in many practical cases. In the 19th and 20th centuries, field models arose to explain these phenomena with more precision. The discovery of electrons and of special relativity led to new action at a distance models providing alternative to field theories. Under our modern understanding, the four fundamental interactions (gravity, electromagnetism, the strong interaction and the weak interaction) in all of physics are not described by action at a distance.
Categories of action
In the study of mechanics, action at a distance is one of three fundamental actions on matter that cause motion. The other two are direct impact (elastic or inelastic collisions) and actions in a continuous medium as in fluid mechanics or solid mechanics.
Historically, physical explanations for particular phenomena have moved between these three categories over time as new models were developed.
Action-at-a-distance and actions in a continuous medium may be easily distinguished when the medium dynamics are visible, like waves in water or in an elastic solid. In the case of electricity or gravity, no medium is required. In the nineteenth century, criteria like the effect of actions on intervening matter, the observation of a time delay, the apparent storage of energy, or even the possibility of a plausible mechanical model for action transmission were all accepted as evidence against action at a distance. Aether theories were alternative proposals to replace apparent action-at-a-distance in gravity and electromagnetism, in terms of continuous action inside an (invisible) medium called "aether".
Direct impact of macroscopic objects seems visually distinguishable from action at a distance. If however the objects are constructed of atoms, and the volume of those atoms is not defined and atoms interact by electric and magnetic forces, the distinction is less clear.
Roles
The concept of action at a distance acts in multiple roles in physics and it can co-exist with other models according to the needs of each physical problem. | Action at a distance | Wikipedia | 472 | 570922 | https://en.wikipedia.org/wiki/Action%20at%20a%20distance | Physical sciences | Physics basics: General | Physics |
One role is as a summary of physical phenomena, independent of any understanding of the cause of such an action. For example, astronomical tables of planetary positions can be compactly summarized using Newton's law of universal gravitation, which assumes the planets interact without contact or an intervening medium. As a summary of data, the concept does not need to be evaluated as a plausible physical model.
Action at a distance also acts as a model explaining physical phenomena even in the presence of other models. Again in the case of gravity, hypothesizing an instantaneous force between masses allows the return time of comets to be predicted as well as predicting the existence of previously unknown planets, like Neptune. These triumphs of physics predated the alternative more accurate model for gravity based on general relativity by many decades.
Introductory physics textbooks discuss central forces, like gravity, by models based on action-at-distance without discussing the cause of such forces or issues with it until the topics of relativity and fields are discussed. For example, see The Feynman Lectures on Physics on gravity.
History
Early inquiries into motion
Action-at-a-distance as a physical concept requires identifying objects, distances, and their motion. In antiquity, ideas about the natural world were not organized in these terms. Objects in motion were modeled as living beings. Around 1600, the scientific method began to take root. René Descartes held a more fundamental view, developing ideas of matter and action independent of theology. Galileo Galilei wrote about experimental measurements of falling and rolling objects. Johannes Kepler's laws of planetary motion summarized Tycho Brahe's astronomical observations. Many experiments with electrical and magnetic materials led to new ideas about forces. These efforts set the stage for Newton's work on forces and gravity.
Newtonian gravity
In 1687 Isaac Newton published his Principia which combined his laws of motion with a new mathematical analysis able to reproduce Kepler's empirical results. His explanation was in the form of a law of universal gravitation: any two bodies are attracted by a force proportional to their mass and inversely proportional to the square of the distance between them. Thus the motions of planets were predicted by assuming forces working over great distances.
This mathematical expression of the force did not imply a cause. Newton considered action-at-a-distance to be an inadequate model for gravity. Newton, in his words, considered action at a distance to be: | Action at a distance | Wikipedia | 490 | 570922 | https://en.wikipedia.org/wiki/Action%20at%20a%20distance | Physical sciences | Physics basics: General | Physics |
Metaphysical scientists of the early 1700s strongly objected to the unexplained action-at-a-distance in Newton's theory. Gottfried Wilhelm Leibniz complained that the mechanism of gravity was "invisible, intangible, and not mechanical". Moreover, initial comparisons with astronomical data were not favorable. As mathematical techniques improved throughout the 1700s, the theory showed increasing success, predicting the date of the return of Halley's comet and aiding the discovery of planet Neptune in 1846. These successes and the increasingly empirical focus of science towards the 19th century led to acceptance of Newton's theory of gravity despite distaste for action-at-a-distance.
Electrical action at a distance
Electrical and magnetic phenomena also began to be explored systematically in the early 1600s. In William Gilbert's early theory of "electric effluvia," a kind of electric atmosphere, he rules out action-at-a-distance on the grounds that "no action can be performed by matter save by contact".
However subsequent experiments, especially those by Stephen Gray showed electrical effects over distance. Gray developed an experiment call the "electric boy" demonstrating electric transfer without direct contact.
Franz Aepinus was the first to show, in 1759, that a theory of action at a distance for electricity provides a simpler replacement for the electric effluvia theory. Despite this success, Aepinus himself considered the nature of the forces to be unexplained: he did "not approve of the doctrine which assumes the possibility of action at a distance", setting the stage for a shift to theories based on aether.
By 1785 Charles-Augustin de Coulomb showed that two electric charges at rest experience a force inversely proportional to the square of the distance between them, a result now called Coulomb's law. The striking similarity to gravity strengthened the case for action at a distance, at least as a mathematical model.
As mathematical methods improved, especially through the work of Pierre-Simon Laplace, Joseph-Louis Lagrange, and Siméon Denis Poisson, more sophisticated mathematical methods began to influence the thinking of scientists. The concept of potential energy applied to small test particles led to the concept of a scalar field, a mathematical model representing the forces throughout space. While this mathematical model is not a mechanical medium, the mental picture of such a field resembles a medium.
Fields as an alternative | Action at a distance | Wikipedia | 488 | 570922 | https://en.wikipedia.org/wiki/Action%20at%20a%20distance | Physical sciences | Physics basics: General | Physics |
Michael Faraday was the first who suggested that action at a distance was inadequate as an account of electric and magnetic forces, even in the form of a (mathematical) potential field. Faraday, an empirical experimentalist, cited three reasons in support of some medium transmitting electrical force: 1) electrostatic induction across an insulator depends on the nature of the insulator, 2) cutting a charged insulator causes opposite charges to appear on each half, and 3) electric discharge sparks are curved at an insulator. From these reasons he concluded that the particles of an insulator must be polarized, with each particle contributing to continuous action. He also experimented with magnets, demonstrating lines of force made visible by iron filings. However, in both cases his field-like model depends on particles that interact through an action-at-a-distance: his mechanical field-like model has no more fundamental physical cause than the long-range central field model.
Faraday's observations, as well as others, led James Clerk Maxwell to a breakthrough formulation in 1865, a set of equations that combined electricity and magnetism, both static and dynamic, and which included electromagnetic radiation – light. Maxwell started with elaborate mechanical models but ultimately produced a purely mathematical treatment using dynamical vector fields. The sense that these fields must be set to vibrate to propagate light set off a search of a medium of propagation; the medium was called the luminiferous aether or the aether.
In 1873 Maxwell addressed action at a distance explicitly. He reviews Faraday's lines of force, carefully pointing out that Faraday himself did not provide a mechanical model of these lines in terms of a medium. Nevertheless the many properties of these lines of force imply these "lines must not be regarded as mere mathematical abstractions". Faraday himself viewed these lines of force as a model, a "valuable aid" to the experimentalist, a means to suggest further experiments. | Action at a distance | Wikipedia | 394 | 570922 | https://en.wikipedia.org/wiki/Action%20at%20a%20distance | Physical sciences | Physics basics: General | Physics |
In distinguishing between different kinds of action Faraday suggested three criteria: 1) do additional material objects alter the action?, 2) does the action take time, and 3) does it depend upon the receiving end? For electricity, Faraday knew that all three criteria were met for electric action, but gravity was thought to only meet the third one. After Maxwell's time a fourth criteria, the transmission of energy, was added, thought to also apply to electricity but not gravity. With the advent of new theories of gravity, the modern account would give gravity all of the criteria except dependence on additional objects.
Fields fade into spacetime
The success of Maxwell's field equations led to numerous efforts in the later decades of the 19th century to represent electrical, magnetic, and gravitational fields, primarily with mechanical models. No model emerged that explained the existing phenomena. In particular no good model for stellar aberration, the shift in the position of stars with the Earth's relative velocity. The best models required the ether to be stationary while the Earth moved, but experimental efforts to measure the effect of Earth's motion through the aether found no effect.
In 1892 Hendrik Lorentz proposed a modified aether based on the emerging microscopic molecular model rather than the strictly macroscopic continuous theory of Maxwell. Lorentz investigated the mutual interaction of a moving solitary electrons within a stationary aether. He rederived Maxwell's equations in this way but, critically, in the process he changed them to represent the wave in the coordinates moving electrons. He showed that the wave equations had the same form if they were transformed using a particular scaling factor,
where is the velocity of the moving electrons and is the speed of light. Lorentz noted that if this factor were applied as a length contraction to moving matter in a stationary ether, it would eliminate any effect of motion through the ether, in agreement with experiment.
In 1899, Henri Poincaré questioned the existence of an aether, showing that the principle of relativity prohibits the absolute motion assumed by proponents of the aether model. He named the transformation used by Lorentz the Lorentz transformation but interpreted it as a transformation between two inertial frames with relative velocity . This transformation makes the electromagnetic equations look the same in every uniformly moving inertial frame. Then, in 1905, Albert Einstein demonstrated that the principle of relativity, applied to the simultaneity of time and the constant speed of light, precisely predicts the Lorentz transformation. This theory of special relativity quickly became the modern concept of spacetime. | Action at a distance | Wikipedia | 512 | 570922 | https://en.wikipedia.org/wiki/Action%20at%20a%20distance | Physical sciences | Physics basics: General | Physics |
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