In physics, a transverse wave is a wave whose oscillations are perpendicular to the direction of the wave's advance. This is in contrast to a longitudinal wave which travels in the direction of its oscillations.
Longitudinal waves are waves in which the vibration of the medium is parallel ("along") to the direction the wave travels and displacement of the medium is in the same direction of the wave propagation. Mechanical longitudinal waves are also called compressional or compression waves, because they produce compression and rarefaction when traveling through a medium, and pressure waves, because they produce increases and decreases in pressure. A wave along the length of a stretched Slinky toy, where the distance between coils increases and decreases, is a good visualization. Real-world examples include sound waves and seismic P-waves.
The mesentery is an organ that attaches the intestines to the posterior abdominal wall in humans and is formed by the double fold of peritoneum. It helps in storing fat and allowing blood vessels, lymphatics, and nerves to supply the intestines, among other functions.
The transverse Mercator map projection is an adaptation of the standard Mercator projection. The transverse version is widely used in national and international mapping systems around the world, including the Universal Transverse Mercator. When paired with a suitable geodetic datum, the transverse Mercator delivers high accuracy in zones less than a few degrees in east-west extent.
Orthoceras is a genus of extinct nautiloid cephalopod restricted to Middle Ordovician-aged marine limestones of the Baltic States and Sweden. This genus is sometimes called Orthoceratites. Note it is sometimes misspelled as Orthocera, Orthocerus or Orthoceros.
Orthocerida is an order of extinct Orthoceratoid cephalopods also known as the Michelinocerida that lived from the Early Ordovician possibly to the Late Triassic. A fossil found in the Caucasus suggests they may even have survived until the Early Cretaceous. They were most common however from the Ordovician to the Devonian.
In the mathematical theory of knots, a finite type invariant, or Vassiliev invariant, is a knot invariant that can be extended to an invariant of certain singular knots that vanishes on singular knots with m + 1 singularities and does not vanish on some singular knot with 'm' singularities. It is then said to be of type or order m.
The Ellesmerocerida is an order of primitive cephalopods belonging to the subclass Nautiloidea with a widespread distribution that lived during the Late Cambrian and Ordovician.
Actinoceras is the principal and root genus of the Actinoceratidae, a major family in the Actinocerida, that lived during the Middle and Late Ordovician. It is an extinct genus of nautiloid cephalopod that thrived in the warm waters of the United States during the Paleozoic era.
Lamellorthoceratidae is a family of fossil orthoceratoids in the Orthocerida, defined by Curt Teichert in 1961. The lamellorthoceratids are placed in the superfamily Orthocerataceae in the Treatise on Invertebrate Paleontology.
Spyroceras is a genus of pseudorthocerids from the Devonian of North America and Europe, defined by Hyatt in 1884. Pseudorthocerids are a kind of orthocertaoid, a taxonomic group within the Nautiloidea. Specifically Spyroceras belongs to the pseudorthocerid family, Spyroceratidae.
The Graciloceratidae is a family of nautiloid cephalopods from the Middle and Upper Ordovician belonging to the Oncocerida, characterized by exogastric cyrtocones that expand slightly or moderately and have thin walled, orthochoanitic marginal or subventral, tubular siphuncles.
The Barrandeoceratidae is a family of coiled nautiloids included in the Tarphycerida that lived from the Middle Ordovician to the Middle Devonian, characterised by mostly compressed shells with a subcentral siphuncle composed of thin-walled segments that may become secondarily ventral.(Flower and Kummel 1950, Sweet 1964).
Bitaunioceras is a genus of Permian orthocerids with a gradually expanding, straight, orthodontic shell with straight transverse sutures and a small, subcentral siphuncle with straight tubular orthochromatic necks.
Polygrammoceras is an orthoconic nautiloid that lived during the period from the middle Ordovician to the early Devonian in what is now North America and Eurasia.
The genus Savageoceras is a barrandeoceratid first known from the Middle Silurian of Illinois consisting of rapidly enlarging, depressed cyrtocones with a trapezoidal section; ventral side wider and flatter than dorsal; sides converging on dorsum. Sutures have slight lateral and ventral lobes and ventrolateral saddles. The surface is covered by transverse striae and has rib-like rings that are more prominent at the ventrolateral shoulders but otherwise vaguely defined. The siphuncle is central; interior unknown.
Gomphoceras is a questionable nautiloid cephalopod genus assigned to the Oncocerida. The family to which it might belong is undetermined.
Geisonoceras is an extinct orthocerid genus named by Hyatt, 1884, and type for the Geisonoceratidae established by Zhuravleva in 1959.
Haydenoceras is a genus of middle Devonian cephalopods originally placed in the Barrandeocerida. The genus can be recognized by its strongly compressed, gradually expanding exogastrically curved shell with a strongly rounded dorsum and acutely angled venter, calling attention to the general form of earlier Bassleroceras. The siphuncle is tubular, central.
Fumicollis is a genus of prehistoric flightless birds from the Late Cretaceous (Coniacian-Santonian) Niobrara Chalk of Kansas.
