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Ephedra is a genus of gymnosperm shrubs. The various species of Ephedra are widespread in many arid regions of the world, ranging across southwestern North America, southern Europe, northern Africa, southwest and central Asia, northern China, and western South America. It is the only extant genus in its family, Ephedra... | Ephedra (plant) | Wikipedia | 435 | 5095984 | https://en.wikipedia.org/wiki/Ephedra%20%28plant%29 | Biology and health sciences | Gymnosperms (except conifers) | Plants |
Evolutionary history
The oldest known members of the genus are from the Early Cretaceous around 125 million years ago, with records being known from the Aptian-Albian of Argentina, China, Portugal and the United States. The fossil record of Ephedra outside of pollen disappears after the Early Cretaceous. Molecular clo... | Ephedra (plant) | Wikipedia | 143 | 5095984 | https://en.wikipedia.org/wiki/Ephedra%20%28plant%29 | Biology and health sciences | Gymnosperms (except conifers) | Plants |
, Plants of the World Online accepted the following species:
Ephedra alata Decne. – North Africa, Arabian Peninsula
Ephedra altissima Desf. non-Bové (1834), non-Delile (1813), non-Buch (1828) (High-climbing jointfir) – North Africa, Canary Islands
Ephedra americana Humb. & Bonpl. ex Willd. – Bolivia, Ecuador, Peru, Arg... | Ephedra (plant) | Wikipedia | 500 | 5095984 | https://en.wikipedia.org/wiki/Ephedra%20%28plant%29 | Biology and health sciences | Gymnosperms (except conifers) | Plants |
Ephedra distachya L. – Joint-pine, Jointfir – southern Europe and central Asia from Portugal to Kazakhstan
Ephedra × eleutherolepis V.A.Nikitin – Tajikistan (hybrid E. intermedia × E. strobilacea)
Ephedra equisetina Bunge – Ma huang – Caucasus, Central Asia, Siberia, Mongolia, Gansu, Hebei, Inner Mongolia, Ningxia, Qin... | Ephedra (plant) | Wikipedia | 512 | 5095984 | https://en.wikipedia.org/wiki/Ephedra%20%28plant%29 | Biology and health sciences | Gymnosperms (except conifers) | Plants |
Ephedra minuta Florin – Qinghai, Sichuan
Ephedra monosperma J.G.Gmel. ex C.A.Mey. (dan zi ma huang) – Siberia, Mongolia, much of China including Tibet and Xinjiang
Ephedra multiflora Phil. ex Stapf – Chile, Argentina
Ephedra nevadensis S.Watson – Nevada Ephedra, Nevada Jointfir, Nevada Mormon-tea – Baja California, Cal... | Ephedra (plant) | Wikipedia | 502 | 5095984 | https://en.wikipedia.org/wiki/Ephedra%20%28plant%29 | Biology and health sciences | Gymnosperms (except conifers) | Plants |
Ephedra strongylensis Brullo et al.
Ephedra sumlingensis P.Sharma & P.L.Uniyal – western Himalayas
Ephedra tilhoana Maire – Chad
Ephedra torreyana S.Watson – Torrey's Ephedra, Torrey's Jointfir, Torrey's Mormon-tea, Cañutillo – Nevada, Utah, Colorado, Arizona, New Mexico, Texas, Chihuahua
Ephedra transitoria Riedl – Ir... | Ephedra (plant) | Wikipedia | 311 | 5095984 | https://en.wikipedia.org/wiki/Ephedra%20%28plant%29 | Biology and health sciences | Gymnosperms (except conifers) | Plants |
Distribution
The genus is found worldwide, in desert regions, but not in Australia.
Ecology
Ephedraceae are adapted to extremely arid regions, growing often in high sunny habitats, and occur as high as 4000 m above sea level in both the Andes and the Himalayas. They make up a significant part of the North American Gr... | Ephedra (plant) | Wikipedia | 443 | 5095984 | https://en.wikipedia.org/wiki/Ephedra%20%28plant%29 | Biology and health sciences | Gymnosperms (except conifers) | Plants |
Economic botany and alkaloid content
The earliest uses of Ephedra species (mahuang) for specific illnesses date back to 5000 BC. Ephedrine and its isomers were isolated in 1881 from Ephedra distachya and characterized by the Japanese organic chemist Nagai Nagayoshi. His work to access Ephedra's active ingredients to is... | Ephedra (plant) | Wikipedia | 347 | 5095984 | https://en.wikipedia.org/wiki/Ephedra%20%28plant%29 | Biology and health sciences | Gymnosperms (except conifers) | Plants |
The lunar south pole is the southernmost point on the Moon. It is of interest to scientists because of the occurrence of water ice in permanently shadowed areas around it. The lunar south pole region features craters that are unique in that the near-constant sunlight does not reach their interior. Such craters are cold... | Lunar south pole | Wikipedia | 461 | 20215858 | https://en.wikipedia.org/wiki/Lunar%20south%20pole | Physical sciences | Solar System | Astronomy |
Cold traps are some of the important places on the lunar south pole region in terms of possible water ice and other volatile deposits. Cold traps can contain water and ice that were originally from comets, meteorites and solar wind-induced iron reduction. From experiments and sample readings, scientists were able to co... | Lunar south pole | Wikipedia | 512 | 20215858 | https://en.wikipedia.org/wiki/Lunar%20south%20pole | Physical sciences | Solar System | Astronomy |
LCROSS
The Lunar Crater Observation and Sensing Satellite (LCROSS) was a robotic spacecraft operated by NASA. The mission was conceived as a low-cost means of determining the nature of hydrogen detected at the polar regions of the Moon. Launched immediately after discovery of lunar water by Chandrayaan-1, the main LCR... | Lunar south pole | Wikipedia | 488 | 20215858 | https://en.wikipedia.org/wiki/Lunar%20south%20pole | Physical sciences | Solar System | Astronomy |
The IM-1 Odysseus lander has taken about six days to travel from the Earth to the Moon. Once in the vicinity of the Moon, the lander spent approximately one more Earth-day orbiting the Moon. This set February 22, 2024 at 11:24 PM UTC as the lander's lunar landing date. The initial aim was to land within the Malapert-A ... | Lunar south pole | Wikipedia | 454 | 20215858 | https://en.wikipedia.org/wiki/Lunar%20south%20pole | Physical sciences | Solar System | Astronomy |
The lunar south pole is a place where scientists may be able to perform unique astronomical observations of radio waves under 30 MHz. The Chinese Longjiang microsatellites were launched in May 2018 to orbit the Moon, and Longjiang-2 operated in this frequency until 31 July 2019. Before Longjiang-2, no space observatory... | Lunar south pole | Wikipedia | 361 | 20215858 | https://en.wikipedia.org/wiki/Lunar%20south%20pole | Physical sciences | Solar System | Astronomy |
Ferricyanide is the name of the anion [Fe(CN)6]3−. It is also called hexacyanoferrate(III) and in rare, but systematic nomenclature, hexacyanidoferrate(III). The most common salt of this anion is potassium ferricyanide, a red crystalline material that is used as an oxidant in organic chemistry.
Properties
[Fe(CN)6]3−... | Ferricyanide | Wikipedia | 315 | 2798024 | https://en.wikipedia.org/wiki/Ferricyanide | Physical sciences | Cyanide salts | Chemistry |
Ferrocyanide is the name of the anion [Fe(CN)6]4−. Salts of this coordination complex give yellow solutions. It is usually available as the salt potassium ferrocyanide, which has the formula K4Fe(CN)6. [Fe(CN)6]4− is a diamagnetic species, featuring low-spin iron(II) center in an octahedral ligand environment. Although... | Ferrocyanide | Wikipedia | 508 | 2798040 | https://en.wikipedia.org/wiki/Ferrocyanide | Physical sciences | Cyanide salts | Chemistry |
Nomenclature
According to the recommendations of IUPAC, ferrocyanide should be called "hexacyanidoferrate(II)". Cyanides as a chemical class were named because they were discovered in ferrocyanide. Ferrocyanide in turn was named in Latin to mean "blue substance with iron." The dye Prussian blue had been first made in t... | Ferrocyanide | Wikipedia | 117 | 2798040 | https://en.wikipedia.org/wiki/Ferrocyanide | Physical sciences | Cyanide salts | Chemistry |
The zosterophylls are a group of extinct land plants that first appeared in the Silurian period. The taxon was first established by Banks in 1968 as the subdivision Zosterophyllophytina; they have since also been treated as the division Zosterophyllophyta or Zosterophyta and the class or plesion Zosterophyllopsida or Z... | Zosterophyll | Wikipedia | 439 | 2799611 | https://en.wikipedia.org/wiki/Zosterophyll | Biology and health sciences | Lycophytes | Plants |
Stomata were present, particularly on the upper axes. Their absence on the lower portions of the axes suggests that this part of the plants may have been submerged, and that the plants dwelt in boggy ground or even shallow water. In many fossils these appear to consist of a slit-like opening in the middle of a single... | Zosterophyll | Wikipedia | 501 | 2799611 | https://en.wikipedia.org/wiki/Zosterophyll | Biology and health sciences | Lycophytes | Plants |
This approach has been widely used alongside previous systems. A consequence is that "lycophyte" and corresponding formal names such as "Lycophyta" and "Lycophytina" are used by different authors in at least two senses: either excluding zosterophylls in the sense of Banks or including them in the sense of Kenrick and C... | Zosterophyll | Wikipedia | 446 | 2799611 | https://en.wikipedia.org/wiki/Zosterophyll | Biology and health sciences | Lycophytes | Plants |
Adoketophyton
Anisophyton
Barinophyton
Bathurstia (B)
Crenaticaulis (B)
Danziella
Deheubarthia
Demersatheca
Discalis
Distichophytum (B)
Gosferia (= Forgesia)
Gosslingia (B)
Guangnania
Gumuia
Hicklingia
Hsua
Huia
Jugumella
Konioria
Macivera
Nothia
Oricilla
Protobarinophyton
Ramoferis
Rebuchia, se... | Zosterophyll | Wikipedia | 250 | 2799611 | https://en.wikipedia.org/wiki/Zosterophyll | Biology and health sciences | Lycophytes | Plants |
A yakhchāl ( "ice pit"; yakh meaning "ice" and chāl meaning "pit") is an ancient type of ice house, which also made ice. They are primarily found in the Dasht-e Lut and Dasht-e-Kavir deserts, whose climates range from cold (BWk) to hot (BWh) desert regions.
In present-day Iran, Afghanistan, and Tajikistan, the term ya... | Yakhchāl | Wikipedia | 507 | 2800195 | https://en.wikipedia.org/wiki/Yakhch%C4%81l | Technology | Heating and cooling | null |
However, they varied greatly, as some used all three components, whereas others were simply a large shade wall over a thin pool.
Ice house
Most yakhchāls operate like a traditional ice house. The tall, conical shape of the building is to optimize the solar chimney effect, creating a convection current to guide any re... | Yakhchāl | Wikipedia | 428 | 2800195 | https://en.wikipedia.org/wiki/Yakhch%C4%81l | Technology | Heating and cooling | null |
The temperature differences between shaded and non-shaded area in most areas where the yakhchāls were constructed often have temperature differences of nearly to cooler, making shade walls necessary for production and storage, as well as giving workers extra time to harvest ice. A wall is usually built in an east–wes... | Yakhchāl | Wikipedia | 481 | 2800195 | https://en.wikipedia.org/wiki/Yakhch%C4%81l | Technology | Heating and cooling | null |
This meant that ice pools could use the cold of the desert nights and/or radiative cooling to freeze water which would later be transported to storage as ice. | Yakhchāl | Wikipedia | 33 | 2800195 | https://en.wikipedia.org/wiki/Yakhch%C4%81l | Technology | Heating and cooling | null |
The Désirée potato (sometimes rendered Desirée or Desiree) is a red-skinned main-crop potato originally bred in the Netherlands in 1962. It has yellow flesh with a distinctive flavour and is a favourite with allotment-holders because of its resistance to drought, and is fairly resistant to disease. It is a versatile, f... | Désirée potato | Wikipedia | 234 | 2800677 | https://en.wikipedia.org/wiki/D%C3%A9sir%C3%A9e%20potato | Biology and health sciences | Root vegetables | Plants |
Ocean acidification is the ongoing decrease in the pH of the Earth's ocean. Between 1950 and 2020, the average pH of the ocean surface fell from approximately 8.15 to 8.05. Carbon dioxide emissions from human activities are the primary cause of ocean acidification, with atmospheric carbon dioxide () levels exceeding 42... | Ocean acidification | Wikipedia | 433 | 2801560 | https://en.wikipedia.org/wiki/Ocean%20acidification | Physical sciences | Climate change | Earth science |
The only solution that would address the root cause of ocean acidification is to reduce carbon dioxide emissions. This is one of the main objectives of climate change mitigation measures. The removal of carbon dioxide from the atmosphere would also help to reverse ocean acidification. In addition, there are some specif... | Ocean acidification | Wikipedia | 471 | 2801560 | https://en.wikipedia.org/wiki/Ocean%20acidification | Physical sciences | Climate change | Earth science |
The carbon cycle describes the fluxes of carbon dioxide () between the oceans, terrestrial biosphere, lithosphere, and atmosphere. The carbon cycle involves both organic compounds such as cellulose and inorganic carbon compounds such as carbon dioxide, carbonate ion, and bicarbonate ion, together referenced as dissolve... | Ocean acidification | Wikipedia | 454 | 2801560 | https://en.wikipedia.org/wiki/Ocean%20acidification | Physical sciences | Climate change | Earth science |
In shallow coastal and shelf regions, a number of factors interplay to affect air-ocean exchange and resulting pH change. These include biological processes, such as photosynthesis and respiration, as well as water upwelling. Also, ecosystem metabolism in freshwater sources reaching coastal waters can lead to large, b... | Ocean acidification | Wikipedia | 507 | 2801560 | https://en.wikipedia.org/wiki/Ocean%20acidification | Physical sciences | Climate change | Earth science |
The saturation state (known as Ω) of seawater for a mineral is a measure of the thermodynamic potential for the mineral to form or to dissolve, and for calcium carbonate is described by the following equation:
Here Ω is the product of the concentrations (or activities) of the reacting ions that form the mineral (Ca2+ ... | Ocean acidification | Wikipedia | 473 | 2801560 | https://en.wikipedia.org/wiki/Ocean%20acidification | Physical sciences | Climate change | Earth science |
At depths of 1000s of meters in the ocean, calcium carbonate shells begin to dissolve as increasing pressure and decreasing temperature shift the chemical equilibria controlling calcium carbonate precipitation. The depth at which this occurs is known as the carbonate compensation depth. Ocean acidification will increas... | Ocean acidification | Wikipedia | 436 | 2801560 | https://en.wikipedia.org/wiki/Ocean%20acidification | Physical sciences | Climate change | Earth science |
The rate of decline differs by region. This is due to complex interactions between different types of forcing mechanisms: "In the tropical Pacific, its central and eastern upwelling zones exhibited a faster pH decline of minus 0.022 to minus 0.026 pH unit per decade." This is thought to be "due to increased upwelling o... | Ocean acidification | Wikipedia | 389 | 2801560 | https://en.wikipedia.org/wiki/Ocean%20acidification | Physical sciences | Climate change | Earth science |
Three of the big five mass extinction events in the geologic past were associated with a rapid increase in atmospheric carbon dioxide, probably due to volcanism and/or thermal dissociation of marine gas hydrates. Elevated CO2 levels impacted biodiversity. Decreased saturation due to seawater uptake of volcanogenic CO2... | Ocean acidification | Wikipedia | 382 | 2801560 | https://en.wikipedia.org/wiki/Ocean%20acidification | Physical sciences | Climate change | Earth science |
Importantly, the rate of change in ocean acidification is much higher than in the geological past. This faster change prevents organisms from gradually adapting, and prevents climate cycle feedbacks from kicking in to mitigate ocean acidification. Ocean acidification is now on a path to reach lower pH levels than at an... | Ocean acidification | Wikipedia | 508 | 2801560 | https://en.wikipedia.org/wiki/Ocean%20acidification | Physical sciences | Climate change | Earth science |
Under normal conditions, calcite and aragonite are stable in surface waters since the carbonate ions are supersaturated with respect to seawater. However, as ocean pH falls, the concentration of carbonate ions also decreases. Calcium carbonate thus becomes undersaturated, and structures made of calcium carbonate are vu... | Ocean acidification | Wikipedia | 508 | 2801560 | https://en.wikipedia.org/wiki/Ocean%20acidification | Physical sciences | Climate change | Earth science |
The fluid in the internal compartments (the coelenteron) where corals grow their exoskeleton is also extremely important for calcification growth. When the saturation state of aragonite in the external seawater is at ambient levels, the corals will grow their aragonite crystals rapidly in their internal compartments, h... | Ocean acidification | Wikipedia | 427 | 2801560 | https://en.wikipedia.org/wiki/Ocean%20acidification | Physical sciences | Climate change | Earth science |
Studies at carbon dioxide seep sites
In some places carbon dioxide bubbles out from the sea floor, locally changing the pH and other aspects of the chemistry of the seawater. Studies of these carbon dioxide seeps have documented a variety of responses by different organisms. Coral reef communities located near carbon ... | Ocean acidification | Wikipedia | 490 | 2801560 | https://en.wikipedia.org/wiki/Ocean%20acidification | Physical sciences | Climate change | Earth science |
Acoustic properties
Another potential route to ecosystem impacts is through bioacoustics. This may occur as ocean acidification can alter the acoustic properties of seawater, allowing sound to propagate further, and increasing ocean noise. This impacts all animals that use sound for echolocation or communication.
Alg... | Ocean acidification | Wikipedia | 451 | 2801560 | https://en.wikipedia.org/wiki/Ocean%20acidification | Physical sciences | Climate change | Earth science |
This experiment showed that when larvae are exposed to a pH of 7.8 ± 0.05 their reaction to environmental cues differs drastically from their reaction to cues at pH equal to current ocean levels. At pH 7.6 ± 0.05 larvae had no reaction to any type of cue. However, a meta-analysis published in 2022 found that the effect... | Ocean acidification | Wikipedia | 447 | 2801560 | https://en.wikipedia.org/wiki/Ocean%20acidification | Physical sciences | Climate change | Earth science |
Meta analyses have quantified the direction and magnitude of the harmful effects of combined ocean acidification, warming and deoxygenation on the ocean. These meta-analyses have been further tested by mesocosm studies that simulated the interaction of these stressors and found a catastrophic effect on the marine food ... | Ocean acidification | Wikipedia | 435 | 2801560 | https://en.wikipedia.org/wiki/Ocean%20acidification | Physical sciences | Climate change | Earth science |
The value of fish caught from US commercial fisheries in 2007 was valued at $3.8 billion and of that 73% was derived from calcifiers and their direct predators. Other organisms are directly harmed as a result of acidification. For example, decrease in the growth of marine calcifiers such as the American lobster, ocean ... | Ocean acidification | Wikipedia | 433 | 2801560 | https://en.wikipedia.org/wiki/Ocean%20acidification | Physical sciences | Climate change | Earth science |
Some carbon removal techniques add alkalinity to the ocean and therefore immediately buffer pH changes which might help the organisms in the region that the extra alkalinity is added to. The two technologies that fall into this category are ocean alkalinity enhancement and electrochemical methods. Eventually, due to di... | Ocean acidification | Wikipedia | 500 | 2801560 | https://en.wikipedia.org/wiki/Ocean%20acidification | Physical sciences | Climate change | Earth science |
Experimental materials include limestone, brucite, olivine and alkaline solutions. Another approach is to use electricity to raise alkalinity during desalination to capture waterborne CO2.
Electrochemical methods
Electrochemical methods, or electrolysis, can strip carbon dioxide directly from seawater. Electrochemical... | Ocean acidification | Wikipedia | 418 | 2801560 | https://en.wikipedia.org/wiki/Ocean%20acidification | Physical sciences | Climate change | Earth science |
The UN Ocean Decade has a program called "Ocean acidification research for sustainability". It was proposed by the Global Ocean Acidification Observing Network (GOA-ON) and its partners, and has been formally endorsed as a program of the UN Decade of Ocean Science for Sustainable Development. The OARS program builds on... | Ocean acidification | Wikipedia | 457 | 2801560 | https://en.wikipedia.org/wiki/Ocean%20acidification | Physical sciences | Climate change | Earth science |
The Intergovernmental Oceanographic Commission (IOC) of UNESCO was identified as the custodian agency for the SDG 14.3.1 Indicator. In this role, IOC-UNESCO is tasked with developing the SDG 14.3.1 Indicator Methodology, the annual collection of data towards the SDG 14.3.1 Indicator and the reporting of progress to the... | Ocean acidification | Wikipedia | 482 | 2801560 | https://en.wikipedia.org/wiki/Ocean%20acidification | Physical sciences | Climate change | Earth science |
By the end of the 20th century the trade-offs between the beneficial role of the ocean in absorbing some 90 % of all heat created, and the accumulation of some 50 % of all fossil fuel CO2 emitted, and the impacts on marine life were becoming more clear. By 2003, the time of planning for the "First Symposium on the Ocea... | Ocean acidification | Wikipedia | 485 | 2801560 | https://en.wikipedia.org/wiki/Ocean%20acidification | Physical sciences | Climate change | Earth science |
The sternum (: sternums or sterna) or breastbone is a long flat bone located in the central part of the chest. It connects to the ribs via cartilage and forms the front of the rib cage, thus helping to protect the heart, lungs, and major blood vessels from injury. Shaped roughly like a necktie, it is one of the largest... | Sternum | Wikipedia | 443 | 30270392 | https://en.wikipedia.org/wiki/Sternum | Biology and health sciences | Skeletal system | Biology |
The manubrium joins with the body of the sternum, the clavicles and the cartilages of the first 1.5 pairs of ribs. The inferior border, oval and rough, is covered with a thin layer of cartilage for articulation with the body. The lateral borders are each marked above by a depression for the first costal cartilage, and ... | Sternum | Wikipedia | 406 | 30270392 | https://en.wikipedia.org/wiki/Sternum | Biology and health sciences | Skeletal system | Biology |
Each outer border, at its superior angle, has a small facet, which with a similar facet on the manubrium, forms a cavity for the cartilage of the second rib; below this are four angular depressions which receive the cartilages of the third, fourth, fifth, and sixth ribs. The inferior angle has a small facet, which, wit... | Sternum | Wikipedia | 484 | 30270392 | https://en.wikipedia.org/wiki/Sternum | Biology and health sciences | Skeletal system | Biology |
The sternum develops from two cartilaginous bars one on the left and one on the right, connected with the cartilages of the ribs on each side. These two bars fuse together along the middle to form the cartilaginous sternum which is ossified from six centers: one for the manubrium, four for the body, and one for the xip... | Sternum | Wikipedia | 452 | 30270392 | https://en.wikipedia.org/wiki/Sternum | Biology and health sciences | Skeletal system | Biology |
The xiphoid process may become joined to the body before the age of thirty, but this occurs more frequently after forty; on the other hand, it sometimes remains ununited in old age. In advanced life the manubrium is occasionally joined to the body by bone. When this takes place, however, the bony tissue is generally on... | Sternum | Wikipedia | 392 | 30270392 | https://en.wikipedia.org/wiki/Sternum | Biology and health sciences | Skeletal system | Biology |
Fractures of the sternum are rather uncommon. They may result from trauma, such as when a driver's chest is forced into the steering column of a car in a car accident. A fracture of the sternum is usually a comminuted fracture. The most common site of sternal fractures is at the sternal angle. Some studies reveal tha... | Sternum | Wikipedia | 433 | 30270392 | https://en.wikipedia.org/wiki/Sternum | Biology and health sciences | Skeletal system | Biology |
Other animals
The sternum, in vertebrate anatomy, is a flat bone that lies in the middle front part of the rib cage. It is endochondral in origin. It probably first evolved in early tetrapods as an extension of the pectoral girdle; it is not found in fish. In amphibians and reptiles, it is typically a shield-shaped str... | Sternum | Wikipedia | 329 | 30270392 | https://en.wikipedia.org/wiki/Sternum | Biology and health sciences | Skeletal system | Biology |
Belemnitida (or belemnites) is an extinct order of squid-like cephalopods that existed from the Late Triassic to Late Cretaceous. Unlike squid, belemnites had an internal skeleton that made up the cone. The parts are, from the arms-most to the tip: the tongue-shaped pro-ostracum, the conical phragmocone, and the pointy... | Belemnitida | Wikipedia | 383 | 30275643 | https://en.wikipedia.org/wiki/Belemnitida | Biology and health sciences | Cephalopods | Animals |
The belemnite cone is composed of three parts. Going from arms to tip, these are the tongue-shaped pro-ostracum; the conical, chambered phragmocone; and the spear-shaped guard at the very tip. The guard is attached to the phragmocone in a socket called the alveolus. The cone, in life, would have been encased in muscle ... | Belemnitida | Wikipedia | 495 | 30275643 | https://en.wikipedia.org/wiki/Belemnitida | Biology and health sciences | Cephalopods | Animals |
Belemnites had a radula – the "tongue" embedded in the buccal mass, the first part of a gastropod digestive system – similar to open ocean predatory cephalopods. The radula had rows of seven teeth, consistent with modern predatory squid. The statocysts – which give a sense of balance and function much like the cochlea ... | Belemnitida | Wikipedia | 333 | 30275643 | https://en.wikipedia.org/wiki/Belemnitida | Biology and health sciences | Cephalopods | Animals |
Limbs and hooks
Belemnites had 10 hooked arms of, more or less, equal length with suckers. The hooks were rarely larger than , and increased in size toward the midsection of the arm, possibly because the midsection is where maximum power could be exerted when grabbing, or bigger hooks on the extremities of the arm incr... | Belemnitida | Wikipedia | 390 | 30275643 | https://en.wikipedia.org/wiki/Belemnitida | Biology and health sciences | Cephalopods | Animals |
The males, like in modern squid, probably had one or two hectocotyli - long, modified arms used in copulation or combat with other males. Instead of several hooks, the hectocotyli feature a pair of enlarged hooks—mega-onychites—to latch onto the female at a safe distance to prevent getting stuck with one of her hooks. ... | Belemnitida | Wikipedia | 419 | 30275643 | https://en.wikipedia.org/wiki/Belemnitida | Biology and health sciences | Cephalopods | Animals |
Much like in cuttlefish, nautiluses, and ammonites, the number and successive size of the chambers of the phragmocone are used to analyze the growth of an individual over their life. Successive belemnite chambers tend to increase in size exponentially. Unlike other cephalopods, there is no decreasing trend of chamber s... | Belemnitida | Wikipedia | 307 | 30275643 | https://en.wikipedia.org/wiki/Belemnitida | Biology and health sciences | Cephalopods | Animals |
Belemnite guards have sometimes been found with fractures with signs of healing. It has been interpreted in the past that these are evidence of digging, with belemnites using their guard to dig up prey on the seafloor; however, belemnites are now generally interpreted to have been open ocean predators. A deformed, zigz... | Belemnitida | Wikipedia | 273 | 30275643 | https://en.wikipedia.org/wiki/Belemnitida | Biology and health sciences | Cephalopods | Animals |
Belemnites, being coleoids, derive from the orthoconic (conical) Devonian belemnoid order Aulacocerida, which, in turn, is derived from the Devonian Bactritida. Belemnites were traditionally thought to have evolved in northern Europe in the Hettangian stage of the Early Jurassic 201.6–197 million years ago (mya) and la... | Belemnitida | Wikipedia | 425 | 30275643 | https://en.wikipedia.org/wiki/Belemnitida | Biology and health sciences | Cephalopods | Animals |
The first mention of belemnites in writing comes from the Greek philosopher Theophrastus, who lived in the 4th and 3rd century BCE, in his book De Animalibus Quæ Dicuntur Invidere who described it as lyngurium, lynx urine which had been buried and solidified. Pliny the Elder, in the first century CE, did not believe in... | Belemnitida | Wikipedia | 489 | 30275643 | https://en.wikipedia.org/wiki/Belemnitida | Biology and health sciences | Cephalopods | Animals |
Phylogeny
Belemnites were cephalopods. Having no outer shells, they are classified into the subclass Coleoidea. In 1994, American geologist Peter Doyle defined Coleoidea as composed of three superorders: Decapodiformes (squid and cuttlefish), Octopodiformes (octopuses), and Belemnoidea; with Belemnoidea containing the ... | Belemnitida | Wikipedia | 382 | 30275643 | https://en.wikipedia.org/wiki/Belemnitida | Biology and health sciences | Cephalopods | Animals |
The order Belemnitida is a monophyletic taxon, consisting of a common ancestor and all of its descendants, and is characterized by the possession of ten hooked appendages, a multilayered outer wall of the phragmocone, and a septum between the pro-ostracum and the phragmocone. Belemnitida is separated into two suborders... | Belemnitida | Wikipedia | 250 | 30275643 | https://en.wikipedia.org/wiki/Belemnitida | Biology and health sciences | Cephalopods | Animals |
Family Dimitobelidae
Conobelus
Dimitobelus
Pumiliobelus
Family Belemnitellidae
Actinocamax
Belemnitella
Belemnites
Family Belemnopseidae
Belemnopsis
Vaunagites
Family Cylindroteuthidae
Cylindroteuthis
Family Dicoelitidae
Dicoelites
Family Duvaliidae
Duvalia
Pseudobelus
Rhopaloteuthis
Pseudoduvalia
Family Hastitidae
Has... | Belemnitida | Wikipedia | 321 | 30275643 | https://en.wikipedia.org/wiki/Belemnitida | Biology and health sciences | Cephalopods | Animals |
Belemnite remains are found in what were littoral (nearshore) and mid-shelf zones. To hunt, they may have quickly or stealthily grabbed prey, maintaining a grip with the hooks, and then dove down to eat. It is traditionally thought they resided on the shelf their entire life, and preyed on crustaceans and other mollusk... | Belemnitida | Wikipedia | 469 | 30275643 | https://en.wikipedia.org/wiki/Belemnitida | Biology and health sciences | Cephalopods | Animals |
Large accumulations of guards are commonly found and have been nicknamed "belemnite battlefields". The most quoted explanation is that belemnites were semelparous and died shortly after spawning, much like modern coleoids which migrate from the ocean to the shelf area. In battlefields comprising both adults and juvenil... | Belemnitida | Wikipedia | 366 | 30275643 | https://en.wikipedia.org/wiki/Belemnitida | Biology and health sciences | Cephalopods | Animals |
Belemnite guards have been known since antiquity, and much folklore has evolved since.
The symbol of the Egyptian god Min has been described, among others, as two fossil belemnites.
Before belemnites were identified as fossils, it was believed the guards were some gemstones, namely lyngurium and amber. After a thunders... | Belemnitida | Wikipedia | 224 | 30275643 | https://en.wikipedia.org/wiki/Belemnitida | Biology and health sciences | Cephalopods | Animals |
Azhdarchidae (from the Persian word , , a dragon-like creature in Persian mythology) is a family of pterosaurs known primarily from the Late Cretaceous Period, though an isolated vertebra apparently from an azhdarchid is known from the Early Cretaceous as well (late Berriasian age, about 140 million years ago). Azhdarc... | Azhdarchidae | Wikipedia | 394 | 3757010 | https://en.wikipedia.org/wiki/Azhdarchidae | Biology and health sciences | Pterosaurs | Animals |
It had been suggested azhdarchids were skimmers, but further research has cast doubt on this idea, demonstrating that azhdarchids lacked the necessary adaptations for a skim-feeding lifestyle, and that they may have led a more terrestrial existence similar to modern storks and ground hornbills. Most large azhdarchids p... | Azhdarchidae | Wikipedia | 400 | 3757010 | https://en.wikipedia.org/wiki/Azhdarchidae | Biology and health sciences | Pterosaurs | Animals |
Phylogeny
Two of the most complete cladograms that include the family Azhdarchidae are presented below. The first one is by Brian Andres in 2021, in which Azhdarchidae was found to be the sister taxon to Montanazhdarcho within the clade Azhdarchiformes. Within Azhdarchidae, two different subfamilies were recovered, th... | Azhdarchidae | Wikipedia | 381 | 3757010 | https://en.wikipedia.org/wiki/Azhdarchidae | Biology and health sciences | Pterosaurs | Animals |
Former and possible azhdarchid genera
There have been many pterosaur genera that were once assigned to the Azhdarchidae, but have since been reassigned to other pterosaur groups. Alanqa and Argentinadraco, for example, have sometimes been referred to Azhdarchidae, but recent phylogenetic studies have recovered these a... | Azhdarchidae | Wikipedia | 264 | 3757010 | https://en.wikipedia.org/wiki/Azhdarchidae | Biology and health sciences | Pterosaurs | Animals |
In graph theory, an edge contraction is an operation that removes an edge from a graph while simultaneously merging the two vertices that it previously joined. Edge contraction is a fundamental operation in the theory of graph minors. Vertex identification is a less restrictive form of this operation.
Definition
The ... | Edge contraction | Wikipedia | 469 | 3758115 | https://en.wikipedia.org/wiki/Edge%20contraction | Mathematics | Graph theory | null |
Path contraction
Path contraction occurs upon the set of edges in a path that contract to form a single edge between the endpoints of the path. Edges incident to vertices along the path are either eliminated, or arbitrarily (or systematically) connected to one of the endpoints.
Twisting
Consider two disjoint graphs a... | Edge contraction | Wikipedia | 430 | 3758115 | https://en.wikipedia.org/wiki/Edge%20contraction | Mathematics | Graph theory | null |
Ice pellets (Canadian English) or sleet (American English) is a form of precipitation consisting of small, hard, translucent balls of ice. Ice pellets are different from graupel ("soft hail"), which is made of frosty white opaque rime, and from a mixture of rain and snow, which is a slushy liquid or semisolid. Ice pe... | Ice pellets | Wikipedia | 434 | 3762639 | https://en.wikipedia.org/wiki/Ice%20pellets | Physical sciences | Precipitation | Earth science |
Effects
In most parts of the world, ice pellets only occur for brief periods and do not accumulate a significant and troublesome amount. However, across the eastern United States and southeastern Canada, warm air flowing north from the Gulf of Mexico ahead of a strong synoptic-scale storm system can overrun cold, den... | Ice pellets | Wikipedia | 175 | 3762639 | https://en.wikipedia.org/wiki/Ice%20pellets | Physical sciences | Precipitation | Earth science |
The spinal cord is a long, thin, tubular structure made up of nervous tissue that extends from the medulla oblongata in the lower brainstem to the lumbar region of the vertebral column (backbone) of vertebrate animals. The center of the spinal cord is hollow and contains a structure called the central canal, which cont... | Spinal cord | Wikipedia | 507 | 21294842 | https://en.wikipedia.org/wiki/Spinal%20cord | Biology and health sciences | Nervous system | null |
The spinal cord is continuous with the caudal portion of the medulla, running from the base of the skull to the body of the first lumbar vertebra. It does not run the full length of the vertebral column in adults. It is made of 31 segments from which branch one pair of sensory nerve roots and one pair of motor nerve ro... | Spinal cord | Wikipedia | 441 | 21294842 | https://en.wikipedia.org/wiki/Spinal%20cord | Biology and health sciences | Nervous system | null |
In cross-section, the peripheral region of the cord contains neuronal white matter tracts containing sensory and motor axons. Internal to this peripheral region is the grey matter, which contains the nerve cell bodies arranged in the three grey columns that give the region its butterfly-shape. This central region surro... | Spinal cord | Wikipedia | 490 | 21294842 | https://en.wikipedia.org/wiki/Spinal%20cord | Biology and health sciences | Nervous system | null |
The spinal cord proper terminates in a region called the conus medullaris, while the pia mater continues as an extension called the filum terminale, which anchors the spinal cord to the coccyx. The cauda equina ("horse's tail") is a collection of nerves inferior to the conus medullaris that continue to travel through t... | Spinal cord | Wikipedia | 477 | 21294842 | https://en.wikipedia.org/wiki/Spinal%20cord | Biology and health sciences | Nervous system | null |
Although the spinal cord cell bodies end around the L1/L2 vertebral level, the spinal nerves for each segment exit at the level of the corresponding vertebra. For the nerves of the lower spinal cord, this means that they exit the vertebral column much lower (more caudally) than their roots. As these nerves travel from ... | Spinal cord | Wikipedia | 376 | 21294842 | https://en.wikipedia.org/wiki/Spinal%20cord | Biology and health sciences | Nervous system | null |
The major contribution to the arterial blood supply of the spinal cord below the cervical region comes from the radially arranged posterior and anterior radicular arteries, which run into the spinal cord alongside the dorsal and ventral nerve roots, but with one exception do not connect directly with any of the three l... | Spinal cord | Wikipedia | 199 | 21294842 | https://en.wikipedia.org/wiki/Spinal%20cord | Biology and health sciences | Nervous system | null |
The spinal cord is made from part of the neural tube during development. There are four stages of the spinal cord that arises from the neural tube: The neural plate, neural fold, neural tube, and the spinal cord. Neural differentiation occurs within the spinal cord portion of the tube. As the neural tube begins to deve... | Spinal cord | Wikipedia | 506 | 21294842 | https://en.wikipedia.org/wiki/Spinal%20cord | Biology and health sciences | Nervous system | null |
There are two ascending somatosensory pathways in the spinal cord. The dorsal column–medial lemniscus pathway (DCML pathway), and the anterolateral system (ALS).
DCML
In the dorsal column-medial lemniscus pathway, a primary neuron's axon enters the spinal cord and then enters the dorsal column. Here the dorsal column ... | Spinal cord | Wikipedia | 430 | 21294842 | https://en.wikipedia.org/wiki/Spinal%20cord | Biology and health sciences | Nervous system | null |
Anterolateral system
The anterolateral system (ALS) works somewhat differently. Its primary neurons axons enter the spinal cord and then ascend one to two levels before synapsing in the substantia gelatinosa. The tract that ascends before synapsing is known as Lissauer's tract. After synapsing, secondary axons decussat... | Spinal cord | Wikipedia | 465 | 21294842 | https://en.wikipedia.org/wiki/Spinal%20cord | Biology and health sciences | Nervous system | null |
From the levels of L2 to T1, proprioceptive information enters the spinal cord and ascends ipsilaterally, where it synapses in Clarke's nucleus. The secondary neuronal axons continue to ascend ipsilaterally and then pass into the cerebellum via the inferior cerebellar peduncle. This tract is known as the dorsal spinoce... | Spinal cord | Wikipedia | 329 | 21294842 | https://en.wikipedia.org/wiki/Spinal%20cord | Biology and health sciences | Nervous system | null |
Cortical upper motor neurons originate from Brodmann areas 1, 2, 3, 4, and 6 and then descend in the posterior limb of the internal capsule, through the crus cerebri, down through the pons, and to the medullary pyramids, where about 90% of the axons cross to the contralateral side at the decussation of the pyramids. Th... | Spinal cord | Wikipedia | 398 | 21294842 | https://en.wikipedia.org/wiki/Spinal%20cord | Biology and health sciences | Nervous system | null |
The anterior corticospinal tract descends ipsilaterally in the anterior column, where the axons emerge and either synapse on lower ventromedial (VM) motor neurons in the ventral horn ipsilaterally or descussate at the anterior white commissure where they synapse on VM lower motor neurons contralaterally. The tectospina... | Spinal cord | Wikipedia | 423 | 21294842 | https://en.wikipedia.org/wiki/Spinal%20cord | Biology and health sciences | Nervous system | null |
Damage to upper motor neuron axons in the spinal cord results in a characteristic pattern of ipsilateral deficits. These include hyperreflexia, hypertonia and muscle weakness. Lower motor neuronal damage results in its own characteristic pattern of deficits. Rather than an entire side of deficits, there is a pattern re... | Spinal cord | Wikipedia | 415 | 21294842 | https://en.wikipedia.org/wiki/Spinal%20cord | Biology and health sciences | Nervous system | null |
Spinal stenoses at the lumbar region are usually due to disc herniation, hypertrophy of the facet joint and ligamentum flavum, osteophyte, and spondylolisthesis. An uncommon cause of lumbar spinal stenosis is spinal epidural lipomatosis, a condition where there is excessive deposit of fat in the epidural space, causin... | Spinal cord | Wikipedia | 257 | 21294842 | https://en.wikipedia.org/wiki/Spinal%20cord | Biology and health sciences | Nervous system | null |
A pony is a type of small horse, usually measured under a specified height at maturity. Ponies often have thicker coats, manes and tails, compared to larger horses, and proportionally shorter legs, wider barrels, heavier , thicker necks and shorter heads. In modern use, breed registries and horse shows may define a pon... | Pony | Wikipedia | 506 | 21294852 | https://en.wikipedia.org/wiki/Pony | Biology and health sciences | Horses | null |
By the 20th century, many pony breeds had Arabian and other blood added to make a more refined pony suitable for riding.
Uses
In many parts of the world, ponies are used as working animals, as pack animals and for pulling various horse-drawn vehicles. They are seen in many different equestrian pursuits. Some breeds, ... | Pony | Wikipedia | 422 | 21294852 | https://en.wikipedia.org/wiki/Pony | Biology and health sciences | Horses | null |
Ponies are generally considered intelligent and friendly, though sometimes they also are described as stubborn or cunning. The differences of opinion often result from an individual pony's degree of proper training. Ponies trained by inexperienced individuals, or only ridden by beginners, can turn out to be spoiled bec... | Pony | Wikipedia | 463 | 21294852 | https://en.wikipedia.org/wiki/Pony | Biology and health sciences | Horses | null |
Conversely, the term "pony" is occasionally used to describe horses of normal height. Horses used for polo are often called "polo ponies" regardless of height, even though they are often of Thoroughbred breeding and often well over . American Indigenous tribes also have the tradition of referring to their horses as "po... | Pony | Wikipedia | 201 | 21294852 | https://en.wikipedia.org/wiki/Pony | Biology and health sciences | Horses | null |
The lemon (Citrus × limon) is a species of small evergreen tree in the Citrus genus of the flowering plant family Rutaceae. The lemon is a hybrid of the citron and the bitter orange. Its origins are uncertain, but some evidence suggests lemons originated during the 1st millennium BC in what is now northeastern India.
... | Lemon | Wikipedia | 428 | 21299730 | https://en.wikipedia.org/wiki/Lemon | Biology and health sciences | Sapindales | null |
Lemons entered Europe near southern Italy no later than the second century AD, during the time of Ancient Rome. They were later introduced to Persia and then to Iraq and Egypt around 700 AD. The lemon was first recorded in literature in a 10th-century Arabic treatise on farming; it was used as an ornamental plant in ea... | Lemon | Wikipedia | 509 | 21299730 | https://en.wikipedia.org/wiki/Lemon | Biology and health sciences | Sapindales | null |
The 'Eureka' grows year-round and abundantly. This is the common supermarket lemon, also known as "Four Seasons" (Quatre Saisons) because of its ability to produce fruit and flowers together throughout the year. This variety is also available as a plant for domestic customers. There is also a pink-fleshed Eureka lemon ... | Lemon | Wikipedia | 455 | 21299730 | https://en.wikipedia.org/wiki/Lemon | Biology and health sciences | Sapindales | null |
Lemon peel is used in the manufacture of pectin, a gelling agent and stabilizer in food and other products. In Mediterranean countries including Morocco, lemons are preserved in jars or barrels of salt. The salt penetrates the peel and rind, softening them, and curing them so that they last almost indefinitely.
Lemon... | Lemon | Wikipedia | 437 | 21299730 | https://en.wikipedia.org/wiki/Lemon | Biology and health sciences | Sapindales | null |
Lemons appear in paintings, pop art, and novels. A wall painting in the tomb of Nakht in 15th century BC Egypt depicts a woman in a festival, holding a lemon. In the 17th century, Giovanna Garzoni painted a Still Life with Bowl of Citrons, the fruits still attached to leafy flowering twigs, with a wasp on one of the fr... | Lemon | Wikipedia | 250 | 21299730 | https://en.wikipedia.org/wiki/Lemon | Biology and health sciences | Sapindales | null |
Quartz clocks and quartz watches are timepieces that use an electronic oscillator regulated by a quartz crystal to keep time. This crystal oscillator creates a signal with very precise frequency, so that quartz clocks and watches are at least an order of magnitude more accurate than mechanical clocks. Generally, some f... | Quartz clock | Wikipedia | 497 | 21304320 | https://en.wikipedia.org/wiki/Quartz%20clock | Technology | Clocks | null |
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