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Eurypterus hankeni Tetlie, 2006 – Silurian, Norway
Small Eurypterus species, averaging at long. The largest specimen found is about in length. They can be distinguished by pustules and six scales at the rear margin of their carapaces. Appendages I to IV has two spines on each podomere. The postabdomen have small epim... | Eurypterus | Wikipedia | 369 | 892600 | https://en.wikipedia.org/wiki/Eurypterus | Biology and health sciences | Fossil arthropods | Animals |
Eurypterus lacustris Harlan, 1834 – Silurian, USA & Canada
= Eurypterus pachycheirus Hall, 1859 – Silurian, USA & Canada
= Eurypterus robustus Hall, 1859 – Silurian, USA & Canada
One of the two most common Eurypterus fossils found. It is very similar to E. remipes and often found in the same localities, but the eyes a... | Eurypterus | Wikipedia | 483 | 892600 | https://en.wikipedia.org/wiki/Eurypterus | Biology and health sciences | Fossil arthropods | Animals |
Eurypterus ornatus Leutze, 1958 – Silurian, USA
Ornamentation of pustules on the entire surface of the carapace and at least the first tergite. Does not possess raised scales. Its specific name means 'adorned', from Latin ('adorned, ornate'). Recovered from Fayette, Ohio.
Eurypterus pittsfordensis Sarle, 1903 – Silur... | Eurypterus | Wikipedia | 471 | 892600 | https://en.wikipedia.org/wiki/Eurypterus | Biology and health sciences | Fossil arthropods | Animals |
Eurypterus serratus (Jones & Woodward, 1888) – Silurian, Sweden
Similar to E. pittsfordensis and E. leopoldi but can be distinguished by the dense angular striations on their styliform telson. The specific name means 'serrated', from Latin ('sawn [into pieces]'). Originally discovered from Gotland, Sweden.
Eurypteru... | Eurypterus | Wikipedia | 497 | 892600 | https://en.wikipedia.org/wiki/Eurypterus | Biology and health sciences | Fossil arthropods | Animals |
An alternative hypothesis for Eurypterus swimming behavior is that individuals were capable of underwater flying (or subaqueous flight), in which the sinuous motions and shape of the paddles themselves acting as hydrofoils are enough to generate lift. This type is similar to that found in sea turtles and sea lions. It ... | Eurypterus | Wikipedia | 469 | 892600 | https://en.wikipedia.org/wiki/Eurypterus | Biology and health sciences | Fossil arthropods | Animals |
Eurypterus were most probably marine animals, as their remains are mostly found in intertidal shallow environments. The concentrations of Eurypterus fossils in certain sites has been interpreted to be a result of mass mating and molting behavior. Juveniles were likely to have inhabited nearshore hypersaline environment... | Eurypterus | Wikipedia | 460 | 892600 | https://en.wikipedia.org/wiki/Eurypterus | Biology and health sciences | Fossil arthropods | Animals |
Ontogeny
Juvenile Eurypterus differed from adults in several ways. Their carapaces were narrower and longer (parabolic) in contrast to the trapezoidal carapaces of adults. The eyes are aligned almost laterally but move to a more anterior location during growth. The preabdomen also lengthened, increasing the overall len... | Eurypterus | Wikipedia | 485 | 892600 | https://en.wikipedia.org/wiki/Eurypterus | Biology and health sciences | Fossil arthropods | Animals |
They are now only known from fossils from North America, Europe, and northwestern Asia, cratons that were the former components of Laurussia. While three species of Eurypterus were purportedly discovered in China in 1957, the evidence of them belonging to the genus (or if they were even eurypterids at all) is nonexiste... | Eurypterus | Wikipedia | 231 | 892600 | https://en.wikipedia.org/wiki/Eurypterus | Biology and health sciences | Fossil arthropods | Animals |
Floriculture is the study of the efficient production of the plants that produce showy, colorful flowers and foliage for human enjoyment in human environments. It is a commercially successful branch of horticulture and agriculture found throughout the world. Efficient production practices have been developed over the y... | Floriculture | Wikipedia | 391 | 893280 | https://en.wikipedia.org/wiki/Floriculture | Technology | Horticulture | null |
Protected horticulture (greenhouses) has developed simultaneously with the continued changes in the flower crops and markets. Floriculture is a major component of controlled-environment agriculture (CEA). Floriculture crops have a high value to humans, so the cost of an expensive production system - greenhouses, automa... | Floriculture | Wikipedia | 505 | 893280 | https://en.wikipedia.org/wiki/Floriculture | Technology | Horticulture | null |
The horticulture industry is growing due to the increasing demand for fresh, healthy food, sustainable landscaping, and environmental conservation.
Annual Bedding/Garden Plants
Potted Flowering Plants
Herbaceous Perennial Plants
Foliage Plants, Indoor/Patio Use (Houseplants)
Propagative Floriculture Materials
Cut... | Floriculture | Wikipedia | 322 | 893280 | https://en.wikipedia.org/wiki/Floriculture | Technology | Horticulture | null |
Plant tissue culture, micropropagation
Plant propagation has always been a part of flower and plant gardening. Plant tissue culture began as a way to save orchid embryos as orchid fanciers bred new cultivars. Most horticulture and many botany programs in the world had scientists working on plant propagation through ti... | Floriculture | Wikipedia | 287 | 893280 | https://en.wikipedia.org/wiki/Floriculture | Technology | Horticulture | null |
This success was tied to a relatively deep pot, usually 6–10 inches (15–25 cm) deep or larger. Gravity was sufficient to pull or drain water from the soil so an adequate portion of the soil in the pot was well drained and oxygen would be available to the root system. As US greenhouses began to expand the bedding plant ... | Floriculture | Wikipedia | 471 | 893280 | https://en.wikipedia.org/wiki/Floriculture | Technology | Horticulture | null |
Supplemental lighting
Supplemental lighting for flower crops began with photoperiod treatments and interest expanded to determine whether artificial light from electric lamps could substitute for sunlight during winter conditions. Incandescent lamps were not successful, so floriculture had to wait for lighting technol... | Floriculture | Wikipedia | 363 | 893280 | https://en.wikipedia.org/wiki/Floriculture | Technology | Horticulture | null |
Didelphodon (from [is] "opossum" tooth "tooth") is a genus of extinct metatherian mammal from the Late Cretaceous of North America.
Description
Although perhaps little larger than a Virginia opossum, with a skull length of and a weight of , the teeth have specialized bladelike cusps and carnassial notches, indicat... | Didelphodon | Wikipedia | 369 | 893573 | https://en.wikipedia.org/wiki/Didelphodon | Biology and health sciences | Marsupials | Animals |
Classification
Didelphodon is a stagodontid marsupial related to Eodelphis and Pariadens. The genus appears to descend from the Campanian Eodelphis, and in particular appears to be related to Eodelphis cutleri. Pariadens appears to be more primitive than either Eodelphis or Didelphodon, and is probably sister to their ... | Didelphodon | Wikipedia | 505 | 893573 | https://en.wikipedia.org/wiki/Didelphodon | Biology and health sciences | Marsupials | Animals |
The evolution of Didelphodon and other large stagodontids (as well as large deltatheroidans like Nanocuris) occurs after the local extinction of eutriconodont mammals, suggesting passive or direct ecological replacement. Given that all insectivorous and carnivorous mammal groups suffered heavy losses during the mid-Cre... | Didelphodon | Wikipedia | 92 | 893573 | https://en.wikipedia.org/wiki/Didelphodon | Biology and health sciences | Marsupials | Animals |
Ambulocetus (Latin ambulare "to walk" + cetus "whale") is a genus of early amphibious cetacean from the Kuldana Formation in Pakistan, roughly 48 or 47 million years ago during the Early Eocene (Lutetian). It contains one species, Ambulocetus natans (Latin natans "swimming"), known solely from a near-complete skeleton.... | Ambulocetus | Wikipedia | 438 | 893602 | https://en.wikipedia.org/wiki/Ambulocetus | Biology and health sciences | Cetaceans | Animals |
Ambulocetus inhabited the Indian subcontinent during the Eocene. The area had a hot climate with tropical rainforests and coastal mangroves, and Ambulocetus may have predominantly inhabited brackish areas such as river mouths. It lived alongside requiem sharks, catfish and various other fishes, turtles, crocodiles, the... | Ambulocetus | Wikipedia | 500 | 893602 | https://en.wikipedia.org/wiki/Ambulocetus | Biology and health sciences | Cetaceans | Animals |
The Kuldana Formation is constrained to sometime during the Lutetian stage of the Early Eocene, and the remains may date to 48–47 million years ago. The holotype specimen, HGSP 18507, is a partial skeleton initially discovered preserving an incomplete skull (missing the snout), some elements of the vertebral column and... | Ambulocetus | Wikipedia | 476 | 893602 | https://en.wikipedia.org/wiki/Ambulocetus | Biology and health sciences | Cetaceans | Animals |
Modern cetaceans (Neoceti) are grouped into either the parvorders Mysticeti (baleen whales) or Odontoceti (toothed whales). Neoceti are descended from the ancient Archaeoceti, whose members span the transition from terrestrial to fully aquatic. Archaeoceti are thus paraphyletic (it is a non-natural group which does not... | Ambulocetus | Wikipedia | 351 | 893602 | https://en.wikipedia.org/wiki/Ambulocetus | Biology and health sciences | Cetaceans | Animals |
Though middle-to-late-Eocene archaeocetes are also known from North America, Europe, and Africa, most of these are found only on the Indian subcontinent. Therefore, it is thought cetaceans originally evolved in that region. Based on molecular data, cetaceans are most closely allied with hippos (Whippomorpha), and they ... | Ambulocetus | Wikipedia | 463 | 893602 | https://en.wikipedia.org/wiki/Ambulocetus | Biology and health sciences | Cetaceans | Animals |
Like other archaeocetes which preserve this element, the base of the skull has an undulating contour, probably related to the shape of the nasal canal (and its passage to the throat) and the narrow infraorbital region (the area below the eyes). The base of the skull is wide compared to other archaeocetes, more like tha... | Ambulocetus | Wikipedia | 504 | 893602 | https://en.wikipedia.org/wiki/Ambulocetus | Biology and health sciences | Cetaceans | Animals |
Like Remingtonocetus, Ambulocetus appears to have had a small brain | Ambulocetus | Wikipedia | 18 | 893602 | https://en.wikipedia.org/wiki/Ambulocetus | Biology and health sciences | Cetaceans | Animals |
The snout was quite broad, but the end of the holotype's snout is missing, so it is unclear how long it would have been. The snouts of Basilosaurus and Rodhocetus are short and make up about half the skull's length. Remingtonocetid snouts are quite narrow, which was clearly not the case for Ambulocetus. The mandibular ... | Ambulocetus | Wikipedia | 389 | 893602 | https://en.wikipedia.org/wiki/Ambulocetus | Biology and health sciences | Cetaceans | Animals |
Unlike modern toothed whales which only have one kind of tooth (homodont), archaeocetes are heterodont. Judging by tooth root size, the lower canine was larger than the incisors. The teeth are more robust than those of Rodhocetus and Basilosaurus. The premolars were double rooted, whereas most archaeocetes have single-... | Ambulocetus | Wikipedia | 266 | 893602 | https://en.wikipedia.org/wiki/Ambulocetus | Biology and health sciences | Cetaceans | Animals |
The holotype preserved seven neck vertebrae, which are rather long at . The 16 preserved thoracic vertebrae have thick spinous and transverse processes (which jut upwards and obliquely from the centrum, the vertebral body), with deep depressions on both sides at the tail-end of each centrum which may have supported str... | Ambulocetus | Wikipedia | 384 | 893602 | https://en.wikipedia.org/wiki/Ambulocetus | Biology and health sciences | Cetaceans | Animals |
The holotype preserves 26 ribs, though it is thought to have had 32 total in life. The cortical bone (the outermost layer) is thickest at the neck of the rib (between the joint and the costal cartilage), at max , and was filled with spongy bone. That is, unlike many other aquatic mammals, the ribs did not exhibit osteo... | Ambulocetus | Wikipedia | 456 | 893602 | https://en.wikipedia.org/wiki/Ambulocetus | Biology and health sciences | Cetaceans | Animals |
For the four preserved sacral vertebrae (at the sacrum, between the pelvic bones), the transverse processes of S1 are smaller than those of L8. There is a robust sacroiliac joint with the hip. For the spinous processes, those of S1–S3 are fused. Metapophyses jut straight up from each lamina near the joint, progressivel... | Ambulocetus | Wikipedia | 470 | 893602 | https://en.wikipedia.org/wiki/Ambulocetus | Biology and health sciences | Cetaceans | Animals |
The ilium of the hip of Ambulocetus, like remingtonocetids, features deep depressions to support the rectus femoris and the gluteal muscles. Unlike terrestrial mammals and protocetids, the ischium is expanded dorsolaterally (from left to right, and upwards), which would have increased lever arm for thigh and leg retrac... | Ambulocetus | Wikipedia | 208 | 893602 | https://en.wikipedia.org/wiki/Ambulocetus | Biology and health sciences | Cetaceans | Animals |
The leg proportions of Ambulocetus are similar to otters and seals, and American mammalogist Alfred Brazier Howell predicted similar proportions for a transitional cetacean in 1930. The femur measures , a length similar to the presumably cursorial (capable of running) mesonychian Pachyaena. Archaeocete femora are gener... | Ambulocetus | Wikipedia | 310 | 893602 | https://en.wikipedia.org/wiki/Ambulocetus | Biology and health sciences | Cetaceans | Animals |
The robustness of the cheek teeth, as well as the cusp arrangement, suggests they were involved in crushing, and the fact that both the premolars and molars were involved in crushing indicates Ambulocetus required a large area for crushing, such as when biting into large prey items. Similarly, the broad and powerful sn... | Ambulocetus | Wikipedia | 503 | 893602 | https://en.wikipedia.org/wiki/Ambulocetus | Biology and health sciences | Cetaceans | Animals |
Thewissen hypothesised that Ambulocetus was a drag-powered swimmer, and used its huge feet as its primary propulsion mechanism, much like modern river otters including the giant otter, and species in the genera Lontra and Lutra. Based on the length of the known tail vertebrae, Ambulocetus may have had an inflexible tai... | Ambulocetus | Wikipedia | 488 | 893602 | https://en.wikipedia.org/wiki/Ambulocetus | Biology and health sciences | Cetaceans | Animals |
Hearing
Modern cetaceans have highly specialised ear bones to hear underwater as well as to detect certain frequency ranges. Unlike most other mammals, cetacean ear bones are comparatively thick, and so preserve more reliably in the fossil record. Modern cetaceans have air sinuses surrounding the ear bones (peritympani... | Ambulocetus | Wikipedia | 480 | 893602 | https://en.wikipedia.org/wiki/Ambulocetus | Biology and health sciences | Cetaceans | Animals |
During the Eocene, the Indian subcontinent was an island just beginning its collision with Asia which would eventually lead to the uprising of the Himalayas. The Eocene had a greenhouse climate (no permanent ice sheets at the poles) as opposed to the icehouse climate of today, so, in general, areas were much warmer. Th... | Ambulocetus | Wikipedia | 503 | 893602 | https://en.wikipedia.org/wiki/Ambulocetus | Biology and health sciences | Cetaceans | Animals |
Orthopedic casts or just casts are a form of medical treatment used to immobilize and support bones and soft tissues during the healing process after fractures, surgeries, or severe injuries. By restricting movement, casts provide stability to the affected area, enabling proper alignment and healing of bones, ligaments... | Orthopedic cast | Wikipedia | 492 | 894250 | https://en.wikipedia.org/wiki/Orthopedic%20cast | Technology | Devices | null |
Leg casts are designed to immobilize the lower limb, facilitating the healing process for fractures, ligament injuries, or post-surgical repairs. They provide stability to the affected area, helping to alleviate pain and prevent additional damage. The design of leg casts can vary to cater to specific injuries, from sim... | Orthopedic cast | Wikipedia | 389 | 894250 | https://en.wikipedia.org/wiki/Orthopedic%20cast | Technology | Devices | null |
Ambulation
When a patient is advised not to put weight on an injured limb, mobility aids like crutches, walkers, or wheelchairs can be used to help with movement during the recovery process. These aids protect the injured area while allowing the patient to move around safely. For those who cannot use crutches due to ba... | Orthopedic cast | Wikipedia | 464 | 894250 | https://en.wikipedia.org/wiki/Orthopedic%20cast | Technology | Devices | null |
A common variant, the body jacket, encases the trunk and includes shoulder straps to provide added stabilization, particularly for injuries involving the thoracic or lumbar spine. These casts are meticulously shaped to maintain spinal alignment and prevent movement that could disrupt healing. Despite their efficacy, bo... | Orthopedic cast | Wikipedia | 406 | 894250 | https://en.wikipedia.org/wiki/Orthopedic%20cast | Technology | Devices | null |
Spica cast
A spica cast encases the trunk of the body and one or more limbs, providing immobilization for injuries or conditions requiring stabilization across multiple joints. Spica casts can be used for both upper and lower extremities. For instance, a shoulder spica covers the trunk of the body and one arm, typicall... | Orthopedic cast | Wikipedia | 488 | 894250 | https://en.wikipedia.org/wiki/Orthopedic%20cast | Technology | Devices | null |
To maintain hygiene around the cast, patients should clean and moisturize the exposed skin near the cast edges, being cautious not to let any liquids seep inside. A damp cloth with mild soap can be used for cleaning, followed by gentle drying. Avoid inserting objects, such as sticks or sharp items, into the cast to all... | Orthopedic cast | Wikipedia | 474 | 894250 | https://en.wikipedia.org/wiki/Orthopedic%20cast | Technology | Devices | null |
Bandages of synthetic materials are also used—often knitted fiberglass bandages impregnated with polyurethane, sometimes bandages of thermoplastic. These are lighter and dry much faster than plaster bandages. However, plaster can be more easily moulded to make a snug and therefore more comfortable fit. In addition, pla... | Orthopedic cast | Wikipedia | 501 | 894250 | https://en.wikipedia.org/wiki/Orthopedic%20cast | Technology | Devices | null |
Orthopedic brace are another alternative, commonly used for joint injuries or soft tissue sprains and strains. Braces provide support and stabilize joints like the knee, ankle, or wrist. They are often used for conditions such as ligament sprains, tendinitis, or as post-operative support. Braces are usually made of fab... | Orthopedic cast | Wikipedia | 384 | 894250 | https://en.wikipedia.org/wiki/Orthopedic%20cast | Technology | Devices | null |
The earliest methods of holding a reduced fracture involved using splints. These are rigid strips laid parallel to each other alongside the bone. The Ancient Egyptians used wooden splints made of bark wrapped in linen. They also used stiff bandages for support that were probably derived from embalming techniques. The... | Orthopedic cast | Wikipedia | 406 | 894250 | https://en.wikipedia.org/wiki/Orthopedic%20cast | Technology | Devices | null |
Dominique Jean Larrey (1768–1842) was born in a small town in southern France. He first studied medicine with his uncle, a surgeon in Toulouse. After a short tour of duty as a naval surgeon, he returned to Paris, where he became caught up in the turmoil of the French Revolution, being present at the Storming of the Bas... | Orthopedic cast | Wikipedia | 405 | 894250 | https://en.wikipedia.org/wiki/Orthopedic%20cast | Technology | Devices | null |
A good description of Seutin's technique was provided by Sampson Gamgee who learned it from Seutin in France during the winter of 1851–52 and went on to promote its use in Britain. The limb was initially wrapped in wool, especially over any bony prominences. Pasteboard was then cut into shape to provide a splint, and d... | Orthopedic cast | Wikipedia | 373 | 894250 | https://en.wikipedia.org/wiki/Orthopedic%20cast | Technology | Devices | null |
Plaster of Paris bandages were introduced in different forms by two army surgeons, one at a peacetime home station and another on active service at the front. Antonius Mathijsen (1805–1878) was born in Budel, the Netherlands, where his father was the village doctor. He was educated in Brussels, Maastricht and Utrecht ... | Orthopedic cast | Wikipedia | 411 | 894250 | https://en.wikipedia.org/wiki/Orthopedic%20cast | Technology | Devices | null |
Seutin had travelled through Russia demonstrating his 'starched bandage', and his technique had been adopted by both the Russian army and navy by 1837. Pirogov had observed the use of plaster of Paris bandages in the studio of a sculptor who used strips of linen soaked in liquid plaster of Paris for making models (this... | Orthopedic cast | Wikipedia | 312 | 894250 | https://en.wikipedia.org/wiki/Orthopedic%20cast | Technology | Devices | null |
Cooksonia is an extinct group of primitive land plants, treated as a genus, although probably not monophyletic. The earliest Cooksonia date from the middle of the Silurian (the Wenlock epoch); the group continued to be an important component of the flora until the end of the Early Devonian, a total time span of . While... | Cooksonia | Wikipedia | 469 | 2784391 | https://en.wikipedia.org/wiki/Cooksonia | Biology and health sciences | Pteridophytes | Plants |
Some Cooksonia species bore stomata, which had a role in gas exchange; this was probably to assist in transpiration-driven transport of dissolved materials in the xylem, rather than primarily in photosynthesis, as suggested by their concentration at the tips of the axes. These clusterings of stomata are typically assoc... | Cooksonia | Wikipedia | 386 | 2784391 | https://en.wikipedia.org/wiki/Cooksonia | Biology and health sciences | Pteridophytes | Plants |
The widths of Cooksonia fossils span an order of magnitude. Study of smaller Cooksonia fossils showed that once the tissue required to support the axes, protect them from desiccation, and transport water had been accounted for, no room remained for photosynthetic tissue, and the sporophyte may therefore have been depen... | Cooksonia | Wikipedia | 277 | 2784391 | https://en.wikipedia.org/wiki/Cooksonia | Biology and health sciences | Pteridophytes | Plants |
Taxonomy
The first Cooksonia species were described by William Henry Lang in 1937 and named in honor of Isabel Cookson, with whom he had collaborated and who collected specimens of Cooksonia pertoni in Perton Quarry, Wales, in 1934. There were originally two species, Cooksonia pertoni and C. hemisphaerica. The genus wa... | Cooksonia | Wikipedia | 494 | 2784391 | https://en.wikipedia.org/wiki/Cooksonia | Biology and health sciences | Pteridophytes | Plants |
C. caledonica and the less well-preserved C. crassiparietilis have sporangia which are composed of two 'valves', splitting to release their spores along a line opposite to where they are attached to the stem (i.e. distally).
Phylogeny
For some years, it was suspected that Cooksonia and its species were poorly characte... | Cooksonia | Wikipedia | 443 | 2784391 | https://en.wikipedia.org/wiki/Cooksonia | Biology and health sciences | Pteridophytes | Plants |
Cooksonioids
Cooksonia and similar genera have been placed in a group called "cooksonioids". Originally the term was used for a group of plants fitting the general description of Cooksonia (i.e. simple plants with naked axes showing dichotomous branching and terminal sporangia), but with uncertain evidence of vascular ... | Cooksonia | Wikipedia | 204 | 2784391 | https://en.wikipedia.org/wiki/Cooksonia | Biology and health sciences | Pteridophytes | Plants |
A polyyne is any organic compound with alternating single and triple bonds; that is, a series of consecutive alkynes, with n greater than 1. These compounds are also called polyacetylenes, especially in the natural products and chemical ecology literature, even though this nomenclature more properly refers to acetylen... | Polyyne | Wikipedia | 444 | 2784496 | https://en.wikipedia.org/wiki/Polyyne | Physical sciences | Aliphatic hydrocarbons | Chemistry |
Organic and organosilicon polyynes
Using various techniques, polyynes with n up to 4 or 5 were synthesized during the 1950s. Around 1971, T. R. Johnson and D. R. M. Walton developed the use of end-caps of the form –, where R was usually an ethyl group, to protect the polyyne chain during the chain-doubling reaction u... | Polyyne | Wikipedia | 454 | 2784496 | https://en.wikipedia.org/wiki/Polyyne | Physical sciences | Aliphatic hydrocarbons | Chemistry |
Stability
Long polyyne chains are said to be inherently unstable in bulk because they can cross-link with each other exothermically. Explosions are a real hazard in this area of research. They can be fairly stable, even against moisture and oxygen, if the end hydrogen atoms are replaced with a suitably inert end-group,... | Polyyne | Wikipedia | 492 | 2784496 | https://en.wikipedia.org/wiki/Polyyne | Physical sciences | Aliphatic hydrocarbons | Chemistry |
Biological origins
A wide range of organisms synthesize polyynes. These chemicals have various biological activities, including as flavorings and pigments, chemical repellents and toxins, and potential application to biomedical research and pharmaceuticals. In plants, polyynes are found mainly in Asterids clade, especi... | Polyyne | Wikipedia | 510 | 2784496 | https://en.wikipedia.org/wiki/Polyyne | Physical sciences | Aliphatic hydrocarbons | Chemistry |
Dihydromatricaria acid is a polyyne produced and secreted by soldier beetles as a chemical defense.
In space
The octatetraynyl radicals and hexatriynyl radicals together with their ions are detected in space where hydrogen is rare. Moreover, there have been claims that polyynes have been found in astronomical impact s... | Polyyne | Wikipedia | 91 | 2784496 | https://en.wikipedia.org/wiki/Polyyne | Physical sciences | Aliphatic hydrocarbons | Chemistry |
A belt is a loop of flexible material used to link two or more rotating shafts mechanically, most often parallel. Belts may be used as a source of motion, to transmit power efficiently or to track relative movement. Belts are looped over pulleys and may have a twist between the pulleys, and the shafts need not be paral... | Belt (mechanical) | Wikipedia | 503 | 1364502 | https://en.wikipedia.org/wiki/Belt%20%28mechanical%29 | Technology | Flexible components | null |
Pros and cons
Belt drives are simple, inexpensive, and do not require axially aligned shafts. They help protect machinery from overload and jam, and damp and isolate noise and vibration. Load fluctuations are shock-absorbed (cushioned). They need no lubrication and minimal maintenance. They have high efficiency (90–98%... | Belt (mechanical) | Wikipedia | 442 | 1364502 | https://en.wikipedia.org/wiki/Belt%20%28mechanical%29 | Technology | Flexible components | null |
Because flat belts tend to climb towards the higher side of the pulley, pulleys were made with a slightly convex or "crowned" surface (rather than flat) to allow the belt to self-center as it runs. Flat belts also tend to slip on the pulley face when heavy loads are applied, and many proprietary belt dressings were ava... | Belt (mechanical) | Wikipedia | 509 | 1364502 | https://en.wikipedia.org/wiki/Belt%20%28mechanical%29 | Technology | Flexible components | null |
In general, as with flat belts, rope drives were used for connections from stationary engines to the jack shafts and line shafts of mills, and sometimes from line shafts to driven machinery. Unlike leather belts, however, rope drives were sometimes used to transmit power over relatively long distances. Over long distan... | Belt (mechanical) | Wikipedia | 397 | 1364502 | https://en.wikipedia.org/wiki/Belt%20%28mechanical%29 | Technology | Flexible components | null |
V belts (also style V-belts, vee belts, or, less commonly, wedge rope) solved the slippage and alignment problem. It is now the basic belt for power transmission. They provide the best combination of traction, speed of movement, load of the bearings, and long service life. They are generally endless, and their general ... | Belt (mechanical) | Wikipedia | 498 | 1364502 | https://en.wikipedia.org/wiki/Belt%20%28mechanical%29 | Technology | Flexible components | null |
History of V-belts
Trade journal coverage of V-belts in automobiles from 1916 mentioned leather as the belt material, and mentioned that the V angle was not yet well standardized. The endless rubber V-belt was developed in 1917 by Charles C. Gates of the Gates Rubber Company. Multiple-V-belt drive was first arranged a ... | Belt (mechanical) | Wikipedia | 412 | 1364502 | https://en.wikipedia.org/wiki/Belt%20%28mechanical%29 | Technology | Flexible components | null |
Any V-belt's ability to drive pulleys depends on wrapping the belt around a sufficient angle of the pulley to provide grip. Where a single-V-belt is limited to a simple convex shape, it can adequately wrap at most three or possibly four pulleys, so can drive at most three accessories. Where more must be driven, such as... | Belt (mechanical) | Wikipedia | 459 | 1364502 | https://en.wikipedia.org/wiki/Belt%20%28mechanical%29 | Technology | Flexible components | null |
Film belts
Though often grouped with flat belts, they are actually a different kind. They consist of a very thin belt (0.5–15 millimeters or 100–4000 micrometres) strip of plastic and occasionally rubber. They are generally intended for low-power (less than 10 watts), high-speed uses, allowing high efficiency (up to 98... | Belt (mechanical) | Wikipedia | 492 | 1364502 | https://en.wikipedia.org/wiki/Belt%20%28mechanical%29 | Technology | Flexible components | null |
Standards for use
The open belt drive has parallel shafts rotating in the same direction, whereas the cross-belt drive also bears parallel shafts but rotate in opposite direction. The former is far more common, and the latter not appropriate for timing and standard V-belts unless there is a twist between each pulley so... | Belt (mechanical) | Wikipedia | 286 | 1364502 | https://en.wikipedia.org/wiki/Belt%20%28mechanical%29 | Technology | Flexible components | null |
ISO 9563: This standard specifies requirements and test methods for endless power transmission V-belts and V-ribbed belts.
ISO 4184: This standard specifies the dimensions of classical and narrow V-belts for general use.
ISO 9981: This standard deals with the dimensions of rubber synchronous belt drives.
ISO 9982: This... | Belt (mechanical) | Wikipedia | 450 | 1364502 | https://en.wikipedia.org/wiki/Belt%20%28mechanical%29 | Technology | Flexible components | null |
Factors of power adjustment include speed ratio; shaft distance (long or short); type of drive unit (electric motor, internal combustion engine); service environment (oily, wet, dusty); driven unit loads (jerky, shock, reversed); and pulley-belt arrangement (open, crossed, turned). These are found in engineering handbo... | Belt (mechanical) | Wikipedia | 447 | 1364502 | https://en.wikipedia.org/wiki/Belt%20%28mechanical%29 | Technology | Flexible components | null |
Belt tension
Power transmission is a function of belt tension. However, also increasing with tension is stress (load) on the belt and bearings. The ideal belt is that of the lowest tension that does not slip in high loads. Belt tensions should also be adjusted to belt type, size, speed, and pulley diameters. Belt tensi... | Belt (mechanical) | Wikipedia | 499 | 1364502 | https://en.wikipedia.org/wiki/Belt%20%28mechanical%29 | Technology | Flexible components | null |
Specifications
To fully specify a belt, the material, length, and cross-section size and shape are required. Timing belts, in addition, require that the size of the teeth be given. The length of the belt is the sum of the central length of the system on both sides, half the circumference of both pulleys, and the square... | Belt (mechanical) | Wikipedia | 333 | 1364502 | https://en.wikipedia.org/wiki/Belt%20%28mechanical%29 | Technology | Flexible components | null |
Four-dimensional space (4D) is the mathematical extension of the concept of three-dimensional space (3D). Three-dimensional space is the simplest possible abstraction of the observation that one needs only three numbers, called dimensions, to describe the sizes or locations of objects in the everyday world. For example... | Four-dimensional space | Wikipedia | 482 | 1364622 | https://en.wikipedia.org/wiki/Four-dimensional%20space | Mathematics | Four-dimensional space | null |
Single locations in Euclidean 4D space can be given as vectors or 4-tuples, i.e., as ordered lists of numbers such as . It is only when such locations are linked together into more complicated shapes that the full richness and geometric complexity of higher-dimensional spaces emerge. A hint of that complexity can be se... | Four-dimensional space | Wikipedia | 474 | 1364622 | https://en.wikipedia.org/wiki/Four-dimensional%20space | Mathematics | Four-dimensional space | null |
Higher dimensional non-Euclidean spaces were put on a firm footing by Bernhard Riemann's 1854 thesis, , in which he considered a "point" to be any sequence of coordinates . In 1908, Hermann Minkowski presented a paper consolidating the role of time as the fourth dimension of spacetime, the basis for Einstein's theories... | Four-dimensional space | Wikipedia | 441 | 1364622 | https://en.wikipedia.org/wiki/Four-dimensional%20space | Mathematics | Four-dimensional space | null |
Orthogonality and vocabulary
In the familiar three-dimensional space of daily life, there are three coordinate axes—usually labeled , , and —with each axis orthogonal (i.e. perpendicular) to the other two. The six cardinal directions in this space can be called up, down, east, west, north, and south. Positions along th... | Four-dimensional space | Wikipedia | 415 | 1364622 | https://en.wikipedia.org/wiki/Four-dimensional%20space | Mathematics | Four-dimensional space | null |
In three dimensions, a circle may be extruded to form a cylinder. In four dimensions, there are several different cylinder-like objects. A sphere may be extruded to obtain a spherical cylinder (a cylinder with spherical "caps", known as a spherinder), and a cylinder may be extruded to obtain a cylindrical prism (a cubi... | Four-dimensional space | Wikipedia | 320 | 1364622 | https://en.wikipedia.org/wiki/Four-dimensional%20space | Mathematics | Four-dimensional space | null |
Four-dimensional perception in humans
Research using virtual reality finds that humans, despite living in a three-dimensional world, can, without special practice, make spatial judgments about line segments embedded in four-dimensional space, based on their length (one-dimensional) and the angle (two-dimensional) betw... | Four-dimensional space | Wikipedia | 491 | 1364622 | https://en.wikipedia.org/wiki/Four-dimensional%20space | Mathematics | Four-dimensional space | null |
To understand the nature of four-dimensional space, a device called dimensional analogy is commonly employed. Dimensional analogy is the study of how () dimensions relate to dimensions, and then inferring how dimensions would relate to () dimensions.
The dimensional analogy was used by Edwin Abbott Abbott in the bo... | Four-dimensional space | Wikipedia | 216 | 1364622 | https://en.wikipedia.org/wiki/Four-dimensional%20space | Mathematics | Four-dimensional space | null |
Cross-sections
As a three-dimensional object passes through a two-dimensional plane, two-dimensional beings in this plane would only observe a cross-section of the three-dimensional object within this plane. For example, if a sphere passed through a sheet of paper, beings in the paper would see first a single point. A ... | Four-dimensional space | Wikipedia | 500 | 1364622 | https://en.wikipedia.org/wiki/Four-dimensional%20space | Mathematics | Four-dimensional space | null |
Similarly, objects in the fourth dimension can be mathematically projected to the familiar three dimensions, where they can be more conveniently examined. In this case, the 'retina' of the four-dimensional eye is a three-dimensional array of receptors. A hypothetical being with such an eye would perceive the nature of ... | Four-dimensional space | Wikipedia | 449 | 1364622 | https://en.wikipedia.org/wiki/Four-dimensional%20space | Mathematics | Four-dimensional space | null |
Bounding regions
The dimensional analogy also helps in inferring basic properties of objects in higher dimensions, such as the bounding region. For example, two-dimensional objects are bounded by one-dimensional boundaries: a square is bounded by four edges. Three-dimensional objects are bounded by two-dimensional surf... | Four-dimensional space | Wikipedia | 444 | 1364622 | https://en.wikipedia.org/wiki/Four-dimensional%20space | Mathematics | Four-dimensional space | null |
One of the most heralded science fiction stories regarding true geometric dimensionality, and often recommended as a starting point for those just starting to investigate such matters, is the 1884 novella Flatland by Edwin A. Abbott. Isaac Asimov, in his foreword to the Signet Classics 1984 edition, described Flatland ... | Four-dimensional space | Wikipedia | 510 | 1364622 | https://en.wikipedia.org/wiki/Four-dimensional%20space | Mathematics | Four-dimensional space | null |
Simon Newcomb wrote an article for the Bulletin of the American Mathematical Society in 1898 entitled "The Philosophy of Hyperspace". Linda Dalrymple Henderson coined the term "hyperspace philosophy", used to describe writing that uses higher dimensions to explore metaphysical themes, in her 1983 thesis about the fourt... | Four-dimensional space | Wikipedia | 113 | 1364622 | https://en.wikipedia.org/wiki/Four-dimensional%20space | Mathematics | Four-dimensional space | null |
Sports medicine is a branch of medicine that deals with physical fitness and the treatment and prevention of injuries related to sports and exercise. Although most sports teams have employed team physicians for many years, it is only since the late 20th century that sports medicine emerged as a distinct field of health... | Sports medicine | Wikipedia | 507 | 1365637 | https://en.wikipedia.org/wiki/Sports%20medicine | Biology and health sciences | Fields of medicine | Health |
Related medical specialties
Exercise medicine
Podiatry
Sports cardiology
Emergency medicine
Lifestyle medicine
General practice
Adolescent medicine
Physical medicine and rehabilitation
Rheumatology
Orthopaedic sports medicine
Pediatrics
Occupational medicine
Establishment as a medical specialty
Historical... | Sports medicine | Wikipedia | 508 | 1365637 | https://en.wikipedia.org/wiki/Sports%20medicine | Biology and health sciences | Fields of medicine | Health |
Common sports injuries that can result in seeing a sports medicine specialist are knee and shoulder injuries, fractures, ankle sprains, concussions, cartilage injuries, and more. A sports medicine specialist can also be seen for advice in other areas of health, like nutrition, exercise, supplements, and how to prevent ... | Sports medicine | Wikipedia | 472 | 1365637 | https://en.wikipedia.org/wiki/Sports%20medicine | Biology and health sciences | Fields of medicine | Health |
Doping in sport has a long history with doctors in the sports medicine world being both heroes and villains on different occasions. The presence of trained sports medicine professionals at elite sporting events has been critical in the fight against doping, but sometimes doctors become the enablers of doping and are pa... | Sports medicine | Wikipedia | 490 | 1365637 | https://en.wikipedia.org/wiki/Sports%20medicine | Biology and health sciences | Fields of medicine | Health |
Other practitioners
All of Exercise physiologists, Strength and conditioning coaches, personal trainers, Chiropractors, Osteopaths, Sports psychologists, Sekkotsu, and Sports nutritionists/dietitians can be part of the Sport and Exercise Medicine team.
Journals | Sports medicine | Wikipedia | 56 | 1365637 | https://en.wikipedia.org/wiki/Sports%20medicine | Biology and health sciences | Fields of medicine | Health |
Elemental analysis is a process where a sample of some material (e.g., soil, waste or drinking water, bodily fluids, minerals, chemical compounds) is analyzed for its elemental and sometimes isotopic composition. Elemental analysis can be qualitative (determining what elements are present), and it can be quantitative (... | Elemental analysis | Wikipedia | 471 | 1367595 | https://en.wikipedia.org/wiki/Elemental%20analysis | Physical sciences | Basics_2 | Chemistry |
Neutron activation analysis involves the activation of a sample matrix through the process of neutron capture. The resulting radioactive target nuclei of the sample begin to decay, emitting gamma rays of specific energies that identify the radioisotopes present in the sample. The concentration of each analyte can be de... | Elemental analysis | Wikipedia | 251 | 1367595 | https://en.wikipedia.org/wiki/Elemental%20analysis | Physical sciences | Basics_2 | Chemistry |
In concurrent programming, a monitor is a synchronization construct that prevents threads from concurrently accessing a shared object's state and allows them to wait for the state to change. They provide a mechanism for threads to temporarily give up exclusive access in order to wait for some condition to be met, befo... | Monitor (synchronization) | Wikipedia | 495 | 1367789 | https://en.wikipedia.org/wiki/Monitor%20%28synchronization%29 | Technology | Computer science | null |
Problem statement
For many applications, mutual exclusion is not enough. Threads attempting an operation may need to wait until some condition holds true. A busy waiting loop
while not ( ) do skip
will not work, as mutual exclusion will prevent any other thread from entering the monitor to make the condition true.... | Monitor (synchronization) | Wikipedia | 491 | 1367789 | https://en.wikipedia.org/wiki/Monitor%20%28synchronization%29 | Technology | Computer science | null |
// Method representing each producer thread's behavior:
public method producer() {
while (true) {
task myTask = ...; // Producer makes some new task to be added.
while (queue.isFull()) {} // Busy-wait until the queue is non-full.
queue.enqueue(myTask); // Add the task to the queue.
}
}
... | Monitor (synchronization) | Wikipedia | 480 | 1367789 | https://en.wikipedia.org/wiki/Monitor%20%28synchronization%29 | Technology | Computer science | null |
global RingBuffer queue; // A thread-unsafe ring-buffer of tasks.
global Lock queueLock; // A mutex for the ring-buffer of tasks.
// Method representing each producer thread's behavior:
public method producer() {
while (true) {
task myTask = ...; // Producer makes some new task to be added.
queueL... | Monitor (synchronization) | Wikipedia | 433 | 1367789 | https://en.wikipedia.org/wiki/Monitor%20%28synchronization%29 | Technology | Computer science | null |
This method assures that an inconsistent state does not occur, but wastes CPU resources due to the unnecessary busy-waiting. Even if the queue is empty and producer threads have nothing to add for a long time, consumer threads are always busy-waiting unnecessarily. Likewise, even if consumers are blocked for a long t... | Monitor (synchronization) | Wikipedia | 299 | 1367789 | https://en.wikipedia.org/wiki/Monitor%20%28synchronization%29 | Technology | Computer science | null |
Thus there are three main operations on condition variables:
wait c, m, where c is a condition variable and m is a mutex (lock) associated with the monitor. This operation is called by a thread that needs to wait until the assertion is true before proceeding. While the thread is waiting, it does not occupy the moni... | Monitor (synchronization) | Wikipedia | 378 | 1367789 | https://en.wikipedia.org/wiki/Monitor%20%28synchronization%29 | Technology | Computer science | null |
signal c, also known as notify c, is called by a thread to indicate that the assertion is true. Depending on the type and implementation of the monitor, this moves one or more threads from c's sleep-queue to the "ready queue", or another queue for it to be executed. It is usually considered a best practice to perfor... | Monitor (synchronization) | Wikipedia | 292 | 1367789 | https://en.wikipedia.org/wiki/Monitor%20%28synchronization%29 | Technology | Computer science | null |
As a design rule, multiple condition variables can be associated with the same mutex, but not vice versa. (This is a one-to-many correspondence.) This is because the predicate is the same for all threads using the monitor and must be protected with mutual exclusion from all other threads that might cause the conditi... | Monitor (synchronization) | Wikipedia | 453 | 1367789 | https://en.wikipedia.org/wiki/Monitor%20%28synchronization%29 | Technology | Computer science | null |
// ... (previous code)
// About to enter the monitor.
// Acquire the advisory mutex (lock) associated with the concurrent
// data that is shared between threads,
// to ensure that no two threads can be preemptively interleaved or
// run simultaneously on different cores while executing in critical
// sections that rea... | Monitor (synchronization) | Wikipedia | 481 | 1367789 | https://en.wikipedia.org/wiki/Monitor%20%28synchronization%29 | Technology | Computer science | null |
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