Therefore, there are two mineral phases in larval spicule formation.
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On occasion, sclerocytes may begin a second spicule while the first is still in progress.
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Few long marginalia projecting from the oscular margin may belong to an oscular spicule rim.
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Despite inhabiting the same hosts, T. discolor and T. ovis are distinct species. The size of male and female T. discolor whipworms are 33.9-50.68mm and 36.0—59.0mm respectively. The spicule of T. discolor is 0.94-1.30mm long and has a rounded tip, whereas the spicule of T. ovis is 4.18-5.62mm long and has a pointed tip. In addition to the spicule, the female sex organs can be used to differentiate the two species.
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Females have at least two rows of oocytes and the spicule on the male nematodes is a short ventral process without outgrowths.
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There are also slides of the holotype: BNHM 1877.5.21.1400 (one slide of surface and one spicule preparation) and BNHM 1877.5.21.1401 (slide of a section).
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They project through the surface in some parts of the cormus only, and the club- shaped portion of the spicule lies inside the tube.
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Actines are cylindrical, but they are slightly wider near the centre of the spicule. They are undulated at the distal part and their tip is blunt.
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Embryologic mesenchymal cells (MSC) condense into layers of vascularized primitive connective tissue. Certain mesenchymal cells group together, usually near or around blood vessels, and differentiate into osteogenic cells which deposit bone matrix constitutively. These aggregates of bony matrix are called bone spicules. Separate mesenchymal cells differentiate into osteoblasts, which line up along the surface of the spicule and secrete more osteoid, which increases the size of the spicule.
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Here, the benefit of utilizing ACC may not be for physical strength, but for its periodic need of the exoskeleton to be dissolved for molting. Sea urchins and their larvae utilize the transient form of ACC when forming spicules. The new material, a hydrated form of ACC, for the spicule is transported and deposited at the outer edges of the spicule. Then the deposited material, ACC·H2O, rapidly dehydrates to ACC.
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Its spicules are slender and needle-like; the right spicule is longer than the left spicule or in some cases both spicules are equal in length. Its gubernaculum is narrow and long, with its proximal half being dorsally bent. The distal part of the gubernaculum possesses a transverse lamella-like structure on its dorsal side. The spicules and gubernaculum are well sclerotized, which are orange-coloured, the anterior part of which is colourless.
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A. besseyi has a well- developed and distinct metacorpus. The stylet is small with well-developed knobs. The tail has a mucro with three points. Males have a rose thorn spicule and no bursa.
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USDA, Forest Service B. xylophilus is distinguished by three characteristics: the spicule is flattened into a disc-shaped cucullus at the tip, the front vulval lip is flap-like, and the tail of the female is rounded.
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Suberites are key examples of the importance of the extracellular matrix in animals. In sponges, it is mediated by proteoglycans. Spicule formation is also important for Suberites. Spicules are structural support of sponges, similar to skeletons in higher animals.
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Enterobius gregorii, another human species is morphologically indistinguishable from Enterobius vermicularis except the spicule size. Throughout this article, the word "pinworm" refers to Enterobius. In British usage, however, pinworm refers to Strongyloides, while Enterobius is called threadworm.Vanderkooi 2000, p.
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Posterior end of a male nematode, Gongylonema pulchrum, showing right spicule and gubernaculumphilometrid nematode - E and F represent the gubernaculum In nematodes, the gubernaculum is a hardened or sclerotized structure in the wall that guides the protrusion of the spicule during copulation. For example, in Caenorhabditis elegans, spicules serve to open and dilate the vagina of the hermaphrodite and the gubernaculum is a grooved plate in which the spicules move; the gubernaculum is controlled by two erector and two protractor muscles. The shape and size of the gubernaculum are often important characters for the systematics of nematodes.
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Journal of Experimental Biology 211, 300 (2008) Silicateins are modulated by a group of proteins called silintaphins.W. E. G. Müller et al., The silicatein propeptide acts as inhibitor/modulator of self-organization during spicule axial filament formation. FEBS Journal 280, 1693 (2013).
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Fred Huffman Wilt is an American biologist who was elected a Fellow of the American Association for the Advancement of Science. His research currently includes the endoskeletal spicule of sea urchin embryos, and its biomineralization relative to its cellular and molecular foundation.
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Six-pointed spicule from a siliceous glass sponge Spicules are structural elements found in most sponges. They provide structural support and deter predators. Large spicules that are visible to the naked eye are referred to as megascleres, while smaller, microscopic ones are termed microscleres.
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Chiton tuberculatus can reach a length of about . The basic color is gray green. The valves are ribbed, dull grayish green or greenish brown, with a spicule-covered mantle girdle alternating zones of whitish, green or black.Sea Life BaseArianna Fulvo et Roberto Nistri (2005).
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Durikainema is a genus of two nematodes in the family Robertdollfusidae. Species have a head with a cuticular cephalic inflation, elongated papillae and amphids, and well-developed musculature. Characteristics of the males include a single spicule and a long attenuated tail. Durikainema species parasitize macropods.
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There are about 3,00,000 active spicules at any one time on the Sun's chromosphere. An individual spicule typically reaches 3,000–10,000 km altitude above the photosphere.§1, Two Dynamical Models for Solar Spicules, Paul Lorrain and Serge Koutchmy, Solar Physics 165, #1 (April 1996), pp. 115–137, , .
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The mandibles measure . The dentition is simple, with a large apical tooth and subapical tooth present. The masticatory margin contains no teeth, and the outside areas of the mandibles are concave. The oral surface of the mandibles has dense brushes of stiff, sharp and spicule-like setae.
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Cormus massive, formed of thin, regular and tightly anastomosed tubes. Oscula are simple openings, surrounded by a thin membrane, and located on the top of short conical projections. They receive water from large water-collecting tubes. The skeleton comprises three kinds of spicule: triactines, tetractines and tripods.
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It has also been found that the msp130 gene exhibits a complex pattern of spatial regulation within the PMC syncytium during skeletogenesis. It is suggested that the ectoderm may play a role in controlling skeletal morphogenesis by regulating the expression of PMC- specific gene products involved in spicule biogenesis.
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Calcaronea is a subclass of sea sponges in the class Calcarea. They are Calcarea with the triactines and the basal system of tetractines sagittal (i.e. the rays of the spicule make unequal angles with each other), exceptionally regular. In ontogeny the first spicules to be secreted are diactines.
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2006 Hugot (1983) claims another species affects humans, Enterobius gregorii, which is supposedly a sister species of E. vermicularis, and has a slightly smaller spicule (i.e., sexual organ).Hugot 1983 Its existence is controversial, however; Totkova et al. (2003) consider the evidence to be insufficient,Totkova et al.
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Certain inorganic materials, such as iron and selenium, influence the growth of Suberites, including the primmorph growth and spicule formation.L. Valisano, G. Bavestrello, M. Giovine, A. Arillo, C. Cerrano, Effect of iron and dissolved silica on primmorphs of Petrosia ficiformis (Poiret, 1789). Chemistry & Ecology 23, 233 (2007).A. Krasko et al.
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Adults and juveniles are vermiform in shape. Adults are sexually dimorphic. The male has a poorly developed stylet, a knob-like head, and a sharp, curved spicule enclosed in a sac. The male is 500 to 600 µm in length, while the female is about 550 to 880 µm long.
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H&E; stain. Scale bars are 100μm. TS can be diagnosed based on clinical observations, but is usually confirmed by histopathology of a lesional biopsy or a plucked spicule. Characteristic histological findings include enlarged and abnormally organized hair follicles and hyperproliferation of inner root sheath cells containing large eosinophilic trichohyalin granules.
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Spicules near the solar limb. They appear as dark "hairs" above the solar surface. In solar physics, a spicule is a dynamic jet of plasma, about 300 km diameterQuantifying Spicules, Tiago M. D. Pereira, Bart De Pontieu, and Mats Carlsson, The Astrophysical Journal 759, #1 (October 2012), pp. 18-34, , .
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Studies of biogenic ACC have also shown that these stable forms of ACC are hydrated whereas the transient forms are not. From observations of spicule growth in sea urchins, it seems that ACC is deposited at the location of new mineral growth where it then dehydrates and transforms into calcite.
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Spicules are formed by sclerocytes, which are derived from archaeocytes. The sclerocyte begins with an organic filament, and adds silica to it. Spicules are generally elongated at a rate of 1-10 μm per hour. Once the spicule reaches a certain length it protrudes from the sclerocyte cell body, but remains within the cell’s membrane.
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These sponges are massive or encrusting in form and have a very simple structure with very little variation in spicule form (all spicules tend to be very small). Reproduction is viviparous and the larva is an oval form known as an amphiblastula. This form is usual in calcareous sponges but is less common in other sponges.
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Sponges are some of Earth’s oldest and most ubiquitous animals. The appearance of sponge spicule fossils date back to the Precambrian Era around 580 million years ago. An assemblage of these fossils were found in the Doushanto formation in Southern China. Some circular impressions from the Ediacaran Hills in Southern Australia are also reported to be sponges.
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On one side it has many large, circular osculi (holes) scattered across the surface. On the other side are small pores and a few, widely dispersed, irregular osculi and some groups of smaller ones. Each vent is surrounded by a collar or rim of thickened skin. The tissue forming the sponge is strengthened by the incorporation of a single type of mineralised spicule.
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Monorhaphis is a monotypic genus of siliceous deep sea Hexactinellid sponges. The single species is the type species Monorhaphis chuni, a sponge known for creating a single giant basal spicule (G.B.S.) to anchor the sponge in the sediments. The species was described by Franz Eilhard Schulze in 1904 from specimens collected by the German Deep Sea Expedition in 1898-1899.
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Sponge spicule A sponge defense is a trait that increases a sponge fitness when faced with a spongivore. This is measured relative to another sponge that lacks the defensive trait. Sponge defenses increase survival and/or reproduction (fitness) of sponges under pressure of predation from spongivore. The use of structural and chemical strategies found in sponges are used to deter predation.
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Originally classified in the genus Capillaria, it was reclassified in Aonchotheca in 1999. A. forresteri is small and narrow-bodied, with a length of 13.8 to 19.4 mm in females and 6.8 to 9.2 mm in males. Similar species such as A. putorii differ in features of the alae and spicule (organs in the male), the size of the female, and the texture of the eggs.
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This species of whipworm is white and is known to have a long, thin neck that composes two- thirds of its body, and a short, thick posterior. The male organisms of T. ovis usually range from 53.04mm-75.08mm in length, while their female counterparts are approximately 32.03-70.19mm in length. The spicule length is 4.18-5.62mm for both genders. Both genders also have bacillary bands.
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M. incrustans is an encrusting sponge occurring in patches up to across and high. It is usually some shade of yellow but can range through orange, pink and white. It has a bubbly-looking appearance with internal channels visible through the surface and large, raised oscules. The consistency is fairly soft and elastic but the surface feels crisp because of the vertical spicule bundles supporting it.
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When viewed microscopically, the spicule structure of the two species is very different, A. contorta possessing two-pointed diactines and four-pointed tetractines as well as the three-pointed triactines which C. clathrus is exclusively made up of. This sponge is found on north-eastern Atlantic coasts from the Arctic to the Mediterranean, usually on rocks at depths of 10–30 m, but occasionally in shallower water.
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Clathrina cribrata is a massive species with its body formed from a network of large, irregular tubes. Some of these extend above the main body of the sponge as blind tubes and others are open-ended, serving as osculi. This sponge contains only one type of calcareous spicule. These are three-rayed spicules, known as triactines, and are distributed throughout the tissues in an unorganized way.
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During copulation, one or more chitinized spicules move out of the cloaca and are inserted into the genital pore of the female. Amoeboid sperm crawl along the spicule into the female worm. Nematode sperm is thought to be the only eukaryotic cell without the globular protein G-actin. Eggs may be embryonated or unembryonated when passed by the female, meaning their fertilized eggs may not yet be developed.
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Fossils of glass sponges have been found from around in rocks in Australia, China and Mongolia. Early Cambrian sponges from Mexico belonging to the genus Kiwetinokia show evidence of fusion of several smaller spicules to form a single large spicule. Calcium carbonate spicules of calcareous sponges have been found in Early Cambrian rocks from about in Australia. Other probable demosponges have been found in the Early Cambrian Chengjiang fauna, from .
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However, a recent study published by Baird et al. (2015) refuted this division. In a molecular phylogeny constructed by nuclear ribosomal DNA small and large subunits of Collodaria, the skeleton-lacking and spicule-bearing Sphaerozodae, and its sister clades the skeleton-bearing Collosphaeridae and skeleton- lacking Collophidilidae were found to be monophyletic but Thalassicollidae was found to be paraphyletic. To confirm findings, molecular analyses and morphologies of members were observed.
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The promontory of the tympanic cavity, also known as the cochlear promontory is a rounded hollow prominence, formed by the projection outward of the first turn of the cochlea. It is placed between the oval window and the round window, and is furrowed on its surface by small grooves, for the lodgement of branches of the tympanic plexus. A minute spicule of bone frequently connects the promontory to the pyramidal eminence.
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Fedomia is a genus of organisms resembling sea sponges from the Ediacaran Period. The organisms look like sacs, often connected and occasionally radiating from a central point, and are millimetres to centimetres in length. Their surface is often patterned with a number of concave, star-shaped, spicule-like structures with six to eight points, with a diameter of 2–5 mm; these were probably flexible rather than rigid.
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In the sphenoid bone, the posterior border, smooth and rounded, is received into the lateral fissure of the brain; the medial end of this border forms the anterior clinoid process, which gives attachment to the tentorium cerebelli; it is sometimes joined to the middle clinoid process by a spicule of bone, and when this occurs the termination of the groove for the internal carotid artery is converted into a foramen (carotico-clinoid).
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Biemna variantia is an encrusting sponge forming small cushions seldom more than across, thick in the middle and thinner near the edge. The surface is covered with small conical peaks and has a spiky appearance due to spicule fibres which support the surface. The oscula are irregularly scattered across the surface. Sometimes the cushions are plate-like, cup or fan-shaped, and older individuals may have protuberances and appear lumpy or shaggy.
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They have mandibles which are half the length of Gerontoformica and have a dense brush of spicule-like setae. Furthermore, the vertex (the upper surface of the head) has a pair of oval-shaped rugose (wrinkled) patches. Z. ferox is only known from small, wingless females. The head is similar to those of queens of Z. tonsora, but they can be separated by the lack of ocelli and rugose patches found on the vertex.
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220) by Félix Dujardin as a subgenus of the genus Ascaris Linnaeus, 1758. Dujardin did not make explicit the etymology, but stated that the subgenus included the species in which the males have unequal spicules ("mâles ayant des spicules inégaux"); thus, the name Anisakis is based on anis- (Greek prefix for different) and akis (Greek for spine or spicule). Two species were included in the new subgenus, Ascaris (Anisakis) distans Rudolphi, 1809 and Ascaris (Anisakis) simplex Rudolphi, 1809.
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Near the back end, there are two alae (ridges) at the sides (laterally), which are 40 to 55 (46) μm long; these are located at 10 to 15 μm from another, small ala at the tip. In A. putorii, the lateral alae are much longer and reach the ala at the tip. The spicule, a spikelike structure that functions in reproduction, is curved at the tip and hardened and has a length of 380 to 426 (406) μm.
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The ectoplasm consists of cytoplasmic extensions used for prey capture and also contains food vacuoles for prey digestion. The ectoplasm is surrounded by a periplasmic cortex, also made up of microfibrils, but arranged into twenty plates, each with a hole through which one spicule projects. The cortex is linked to the spines by contractile myonemes, which assist in buoyancy control by allowing the ectoplasm to expand and contract, increasing and decreasing the total volume of the cell.
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The surface of all segments have some sharp tubercles which are ending in short and thick spicule. The front of the head and its interantennae part is joined at the same level as its body, with the former is without raised angle next to the socket of the antennae. The anterior margin is broadly rounded from both sides. The front of the interantennal ridges are low, oblique and wide, with the back part tend to be more slender, granule and flat.
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The yellow boring sponge inhabits living bivalve molluscs, boring into the shell valves. The only parts of the sponge which are visible from the outside are small yellow patches up to in diameter, sometimes containing small oscula (openings). The sponge spicules are silicaceous (glassy) and are scattered throughout the sponge tissues. They consist entirely of megascleres known as "tylostyles", which are a kind of spicule with a single shaft, with a point on one end and a knob on the other.
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Dense spine-like setae cover the labrum (a flap-like structure in front of the mouth); these setae are organised into three rows. Each row, on average, contains around 20 setae which increase in length when they are ventral to the clypeus. The mandibles barely overlap medially, with a single large apical tooth and smaller subapical tooth present. The oral surface is covered in spicule-like setae, in which the inner setae are four times longer than the outer setae.
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RP begins with death of rod photoreceptor cells, which are the only cells in the retina to express rhodopsin and which express it as their most abundant protein. Eventually, loss of rod cells leads to loss of cone cells (cone photoreceptors), the mainstay of human vision. Symptoms of RP include loss of sensitivity to dim light, abnormal visual function, and characteristic bone spicule deposits of pigment in the retina. Affected individuals progressively lose visual field and visual acuity, and photoreceptor cell death can ultimately lead to blindness.
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The molecular mechanisms of skeletogenesis involve several PMC-specific gene products. These include Msp30, a sulfate cell-surface glycoprotein which has been implicated in calcium uptake and deposition, and SM50, SM30, and PM27 which are three proteins of the spicule matrix. SM50 and PM27 are thought to be structurally similar, nonglycosylated, basic proteins whereas SM30 is an acidic glycoprotein. The specific roles of these matrix proteins has yet to be fully elucidated, but it is thought that they may function in the nucleation or orientation of crystal growth.
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Similarly, E. tribuloides also possesses a larval skeleton that arises from a special lineage of cells. In contrast, however, the number and size of its micromeres can vary (from one to three), and they do not precociously invaginate; rather, they ingress during gastrulation and bud off from the tip of the growing archenteron. Although there are numerous molecular differences between the "spicule-forming cells" of E. tribuloides and the primary mesencyhme cells of euechinoids, these two cell lineages are thought to be homologous and have been contrasted in developmental evolution research.
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Pratylenchus penetrans is a migratory nematode which means it moves from root to root and is also an endoparasite which means go into the roots. There are both female and male nematodes, with distinguishing differences being a spicule for the males and that males have a bent tail while females have a straight tail. They reproduce sexually, with the females laying single eggs in the root or soil. After embryonic development within the egg to the first stage juvenile (J1), the nematode molts to the second-stage juvenile (J2) and hatches from the egg.
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These neighbouring cells secrete an organic pellicle on the outside of the developing spicule, whose aragonite is deposited by the central cell; subsequent division of this central cell allows larger spines to be secreted in certain taxa. The organic pellicule is found in most polyplacophora (but not 'basal' chitons, such as Hanleya) but is unusual in aplacophora. Developmentally, sclerite-secreting cells arise from pretrochal and postrochal cells: the 1a, 1d, 2a, 2c, 3c and 3d cells. The shell plates arise primarily from the 2d micromere, although 2a, 2b, 2c and sometimes 3c cells also participate in its secretion.
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Of note is the extension in body length that the worm undergoes each time it is exposed to green light, which is presumably caused by Mac's muscle-relaxant effects. spicule, as would be seen naturally during copulation. Optogenetics provides millisecond-scale temporal precision which allows the experimenter to keep pace with fast biological information processing (for example, in probing the causal role of specific action potential patterns in defined neurons). Indeed, to probe the neural code, optogenetics by definition must operate on the millisecond timescale to allow addition or deletion of precise activity patterns within specific cells in the brains of intact animals, including mammals (see Figure 1).
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For decades, researchers believed spicules could send heat into the corona. However, following observational research in the 1980s, it was found that spicule plasma did not reach coronal temperatures, and so the theory was discounted. As per studies performed in 2010 at the National Center for Atmospheric Research in Colorado, in collaboration with the Lockheed Martin's Solar and Astrophysics Laboratory (LMSAL) and the Institute of Theoretical Astrophysics of the University of Oslo, a new class of spicules (TYPE II) discovered in 2007, which travel faster (up to 100 km/s) and have shorter lifespans, can account for the problem. These jets insert heated plasma into the Sun's outer atmosphere.
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Bart De Pontieu (Lockheed Martin Solar and Astrophysics Laboratory, Palo Alto, California, United States), Robert Erdélyi and Stewart James (both from the University of Sheffield, United Kingdom) hypothesised in 2004 that spicules formed as a result of P-mode oscillations in the Sun's surface, sound waves with a period of about five minutes that causes the Sun's surface to rise and fall at several hundred meters per second (see helioseismology). Magnetic flux tubes that tilted away from the vertical can focus and guide the rising material up into the solar atmosphere to form a spicule. There is still however some controversy about the issue in the solar physics community.
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The anterior border is serrated for articulation with the frontal bone. The posterior border, smooth and rounded, is received into the lateral fissure of the brain; the medial end of this border forms the anterior clinoid process, which gives attachment to the tentorium cerebelli; it is sometimes joined to the middle clinoid process by a spicule of bone, and when this occurs the termination of the groove for the internal carotid artery is converted into a foramen (carotico-clinoid). The lesser wing is connected to the body by two roots, the upper thin and flat, the lower thick and triangular; between the two roots is the optic foramen, for the transmission of the optic nerve and ophthalmic artery.
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In the male, the left spicule (a spine-like copulatory structure) ends with a shoe-like form, not with a tapered, rounded end as in S. thapari. Both males and females have small structures resembling nipples on the ends of their tails, which are absent in S. thapari. Total length is 2.6 to 2.8 mm (0.10 to 0.11 in) in males and 3.4 to 4.9 mm (0.13 to 0.19 in) in females. Maximum width is 55 to 81 μm in males and 100 to 142 μm in females, esophagus length is 612 to 845 μm in males and 823 to 1000 μm in females, and tail length 76 to 112 μm in males and 80 to 90 μm in females.
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Acantharian skeletons are composed of strontium sulfate crystals secreted by vacuoles surrounding each spicule or spine. Acantharians are the only marine organisms known to biomineralize strontium sulfate as the main component of their skeletons, making them unique. Unlike other radiolarians, whose skeletons are made of silica, acantharian skeletons do not fossilize, primarily because strontium sulfate is very scarce in seawater and the crystals dissolve after the acantharians die. The arrangement of the spines is very precise, and is described by what is called the Müllerian law, which can be described in terms of lines of latitude and longitude – the spines lie on the intersections between five of the former, symmetric about an equator, and eight of the latter, spaced uniformly.
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The Carterinids, including the genera Carterina and Zaninettia, have a unique crystalline structure of the test which long complicated their classification. The test in this genus consists of spicules of low-magnesium calcite, bound together with an organic matrix and containing "blebs" of organic matter; this led some researchers to conclude that the test must be agglutinated. However, life studies have failed to find agglutination, and in fact the genus has been discovered on artificial substrate where sediment particles do not accumulate. A 2014 genetic study found carterinids to be an independent lineage within the Globothalamea, and supported the idea of the spicules being secreted as spicule shape differed consistently between specimens of Carterina and Zaninettia collected from the same locality (ovoid in Carterina, rounded-rectangular in Zaninettia).
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This begins on the cranial surface of the bone immediately above the foramen magnum, and is directed lateralward and forward above the condyle. It may be partially or completely divided into two by a spicule of bone; it gives exit to the hypoglossal or twelfth cerebral nerve, and entrance to a meningeal branch of the ascending pharyngeal artery. Behind either condyle is a depression, the condyloid fossa, which receives the posterior margin of the superior facet of the atlas when the head is bent backward; the floor of this fossa is sometimes perforated by the condyloid canal, through which an emissary vein passes from the transverse sinus. Extending lateralward from the posterior half of the condyle is a quadrilateral plate of bone, the jugular process, excavated in front by the jugular notch, which, in the articulated skull, forms the posterior part of the jugular foramen.
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The jugular notch may be divided into two by a bony spicule, the intrajugular process, which projects lateralward above the hypoglossal canal. The under surface of the jugular process is rough, and gives attachment to the Rectus capitis lateralis muscle and the lateral atlanto-occipital ligament; from this surface an eminence, the paramastoid process, sometimes projects downward, and may be of sufficient length to reach, and articulate with, the transverse process of the atlas. Laterally the jugular process presents a rough quadrilateral or triangular area which is joined to the jugular surface of the temporal bone by a plate of cartilage; after the age of twenty-five this plate tends to ossify. The upper surface of the lateral part presents an oval eminence, the jugular tubercle, which overlies the hypoglossal canal and is sometimes crossed by an oblique groove for the glossopharyngeal, vagus, and accessory nerves.
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