نتایج جستجو برای: fish skeleton
تعداد نتایج: 121256 فیلتر نتایج به سال:
The zebrafish is a premier model organism yet lacks a system for assigning postembryonic fish to developmental stages. To provide such a staging series, we describe postembryonic changes in several traits that are visible under brightfield illumination or through vital staining and epiflourescent illumination. These include the swim bladder, median and pelvic fins, pigment pattern, scale format...
The Cretaceous Pierre Shale Group along the Missouri River has produced numerous mosasaur specimens since the western fossil discoveries of Lewis and Clark in 1804 that included a 45-foot “fish.” Many of these marine reptile specimens represent the largest of mosasaurs, the tylosaurines. In 1990 the largest mosasaur heretofore recorded along the Missouri River was discovered near Nicholas Creek...
Algorithmic skeleton has received attention as an efficient method of parallel programming in recent years. Using the method, the programmer can implement parallel programs easily. In this study, a set of efficient algorithmic skeletons is introduced for use in implementing parallel genetic algorithm (PGA).A performance modelis derived for each skeleton that makes the comparison of skeletons po...
The alternative double bonds and conjugation in the polyene compounds are one of the main properties in these compounds. Each carbon-carbon bonds in a polyene compound along the chain has appreciable double-bond character. The p-electrons are therefore not localized but are relatively free to move throughout the entire carbon skeleton as an one-dimensional box. The skeleton be considered as a r...
Lampreys and hagfish, which together are known as the cyclostomes or 'agnathans', are the only surviving lineages of jawless fish. They diverged early in vertebrate evolution, before the origin of the hinged jaws that are characteristic of gnathostome (jawed) vertebrates and before the evolution of paired appendages. However, they do share numerous characteristics with jawed vertebrates. Studie...
formerly the turkmenian stone loach was the only member of the genus metaschistura based on osteological characters. but recently, it is placed in the genus paraschistura based on mtdna coi data. to provide a detailed description of the osteological characteristics of paraschistura cristata (berg 1898), ten specimens of p. cristata were collected from the hari river basin in iran and their oste...
Endolithic algae inhabiting skeletons of living corals appear to be adapted to an extreme environment created by the coral. However, measurements on three coral species from the genus Porites revealed that these corals provide several modes of protection to the algae as well. High concentrations of ultraviolet (UV)-absorbing compounds, mycosporine-like amino acids (MAAs), were found in the tiss...
Visualization of a three-dimensional fish behavior based on the successive feature extraction using the time sequential three-dimensional shape modeling is reported. The principle of the modeling is based on the intersected viewing pyramid consisting of each image boundary of the object and the corresponding focal point. Threedirectional video images are simultaneously acquired and sequential s...
Teleost fishes typically first encounter the environment as free-swimming embryos or larvae. Larvae are morphologically distinct from adults, and major anatomical structures are unformed. Thus, larvae undergo a series of dramatic morphological changes until they reach adult morphology (but are reproductively immature) and are considered juveniles. Free-swimming embryos and larvae are able to pe...
Of the 6,000 reef fish species, only 128 feed on corals [1,2]. Despite being widely available on tropical reefs, corals appear to represent a particularly challenging trophic resource, with mucus- and nematocyst-laden tissues spread over a sharp coral skeleton. Here we report that coral-feeding tubelip wrasses use highly modified lips to suck material from the coral surface. These lips have a s...
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