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Topic Review
Allelopathy of S. canadensis
Solidago canadensis L. is native to North America and have naturalized many other continents including Europa and Asia. Their species is an aggressive colonizer and forms thick monospecific stands. Allelopathy is the chemical interaction between donor plants and recipient plants through allelochemicals. Allelochemicals are produced in some plant parts and released into the vicinity of the donor plants, including their rhizosphere soil either by the root exudation, rainfall leachates, volatilization from the plant parts or decomposition processes of plant residues.
  • 430
  • 07 Dec 2022
Topic Review
Middle Eastern Philosophy
Middle Eastern philosophy includes the various philosophies of the Middle East regions, including the Fertile Crescent, Iran, and Anatolia. Traditions include Ancient Egyptian philosophy, Babylonian philosophy, Jewish philosophy, Iranian/Persian philosophy, and Islamic philosophy.
  • 2.2K
  • 05 Dec 2022
Topic Review
Bearing (Navigation)
In navigation, bearing is the horizontal angle between the direction of an object and another object, or between it and that of true north.
  • 8.3K
  • 05 Dec 2022
Topic Review
Solar Storm of August 1972
The solar storms of August 1972 were a historically powerful series of solar storms with intense to extreme solar flare, solar particle event, and geomagnetic storm components in early August 1972, during solar cycle 20. The storm caused widespread electric‐ and communication‐grid disturbances through large portions of North America as well as satellite disruptions. On August 4, 1972, the storm caused the accidental detonation of numerous U.S. naval mines near Haiphong, North Vietnam. The coronal cloud's transit time from the Sun to the Earth is the fastest ever recorded.
  • 1.8K
  • 05 Dec 2022
Topic Review
Map Symbolization
Map symbolization is the characters, letters, or similar graphic representations used on a map to indicate an object or characteristic in the real world.
  • 1.2K
  • 02 Dec 2022
Topic Review
First Grinnell Expedition
The First Grinnell Expedition of 1850 was the first American effort, financed by Henry Grinnell, to determine the fate of the lost Franklin Polar Expedition. Led by Lieutenant Edwin De Haven, the team explored the accessible areas along Franklin's proposed route. In coordination with British expeditions, they identified the remains of Franklin's Beechy Island winter camp, providing the first solid clues to Franklin's activities during the winter of 1845 before becoming icebound themselves.
  • 233
  • 02 Dec 2022
Topic Review
Celestial Coordinate System
In astronomy, a celestial coordinate system (or celestial reference system) is a system for specifying positions of satellites, planets, stars, galaxies, and other celestial objects relative to physical reference points available to a situated observer (e.g. the true horizon and north cardinal direction to an observer situated on the Earth's surface). Coordinate systems can specify an object's position in three-dimensional space or plot merely its direction on a celestial sphere, if the object's distance is unknown or trivial. The coordinate systems are implemented in either spherical or rectangular coordinates. Spherical coordinates, projected on the celestial sphere, are analogous to the geographic coordinate system used on the surface of Earth. These differ in their choice of fundamental plane, which divides the celestial sphere into two equal hemispheres along a great circle. Rectangular coordinates, in appropriate units, are simply the Cartesian equivalent of the spherical coordinates, with the same fundamental (x, y) plane and primary (x-axis) direction. Each coordinate system is named after its choice of fundamental plane.
  • 1.2K
  • 02 Dec 2022
Topic Review
Mosasaurus
Mosasaurus (/ˌmoʊzəˈsɔːrəs/; "lizard of the Meuse River") is the type genus (defining example) of the mosasaurs, an extinct group of aquatic squamate reptiles. It lived from about 82 to 66 million years ago during the Campanian and Maastrichtian stages of the Late Cretaceous. The earliest fossils of Mosasaurus known to science were found as skulls in a chalk quarry near the Dutch city of Maastricht in the late 18th century, which were initially thought to have been the bones of crocodiles or whales. One skull discovered around 1780, and which was seized by France during the French Revolutionary Wars for its scientific value, was famously nicknamed the "great animal of Maastricht". In 1808, naturalist Georges Cuvier concluded that it belonged to a giant marine lizard with similarities to monitor lizards but otherwise unlike any known living animal. This concept was revolutionary at the time and helped support the then-developing ideas of extinction. Cuvier did not designate a scientific name for the new animal, and this was done by William Daniel Conybeare in 1822 when he named it Mosasaurus in reference to its origin in fossil deposits near the Meuse River. The exact affinities of Mosasaurus as a squamate remain controversial, and scientists continue to debate whether its closest living relatives are monitor lizards or snakes. Traditional interpretations have estimated the maximum length of the largest species, M. hoffmannii, to be up to 17.1 meters (56 ft), making it one of the largest mosasaurs, although some scientists consider this an overestimation with recent estimates suggesting a length closer to 13 meters (43 ft). The skull of Mosasaurus was equipped with robust jaws capable of swinging back and forth and strong muscles capable of powerful bites using dozens of large teeth adapted for cutting prey. Its four limbs were shaped into robust paddles to steer the animal underwater. Its tail was long and ended in a downward bend and a paddle-like fluke. Mosasaurus was a predator possessing excellent vision to compensate for its poor sense of smell, and a high metabolic rate suggesting it was endothermic ("warm-blooded"), an adaptation only found in mosasaurs among squamates. There is considerable morphological variability across the currently-recognized species in Mosasaurus—from the robustly-built M. hoffmannii to the slender and serpentine M. lemonnieri—but an unclear diagnosis (description of distinguishing features) of the type species M. hoffmannii led to a historically problematic classification. As a result, more than fifty different species have been attributed to the genus in the past. A redescription of the type specimen in 2017 helped resolve the taxonomy issue and confirmed at least five species to be within the genus. Another five species still nominally classified within Mosasaurus are planned to be reassessed in a future study. Fossil evidence suggests Mosasaurus inhabited much of the Atlantic Ocean and the seaways adjacent to it. Mosasaurus fossils have been found in places as diverse as North and South America, Europe, Africa, Western Asia, and Antarctica. This distribution encompassed a wide range of oceanic climates including tropical, subtropical, temperate, and subpolar climates. Mosasaurus was a common large predator in these oceans and was positioned at the top of the food chain. Paleontologists believe its diet would have included virtually any animal; it likely preyed on bony fish, sharks, cephalopods, birds, and other marine reptiles including sea turtles and other mosasaurs. It likely preferred to hunt in open water near the surface. From an ecological standpoint, Mosasaurus probably had a profound impact on the structuring of marine ecosystems; its arrival in some locations such as the Western Interior Seaway in North America coincides with a complete turnover of faunal assemblages and diversity. Mosasaurus faced competition with other large predatory mosasaurs such as Prognathodon and Tylosaurus—which were known to feed on similar prey—though they were able to coexist in the same ecosystems through niche partitioning. There were still conflicts among them, as an instance of Tylosaurus attacking a Mosasaurus has been documented. Several fossils document deliberate attacks on Mosasaurus individuals by members of the same species. Infighting likely took place in the form of snout grappling, similarly seen in modern crocodiles today.
  • 5.1K
  • 01 Dec 2022
Topic Review
Mammoth Mountain
Mammoth Mountain is a lava dome complex partially located within the town of Mammoth Lakes, California, in the Inyo National Forest of Madera and Mono Counties. It is home to a large ski area primarily on the Mono County side. Mammoth Mountain was formed in a series of eruptions that ended 57,000 years ago. Mammoth still produces hazardous volcanic gases that kill trees and caused ski patroller fatalities in 2006.
  • 490
  • 01 Dec 2022
Topic Review
Almaguin Highlands
The Almaguin Highlands Region (colloquially known as Almaguin, also referred to as 'the Highlands') in Ontario, Canada, covers approximately 5,200 km2 (2,000 sq mi) comprising the eastern half of Parry Sound District. It is bounded by Muskoka in the south, and by Lake Nipissing and Nipissing District in the north. The eastern edge abuts the western boundary of Algonquin Provincial Park, whereas the western boundary of the Almaguin Highlands is generally regarded to be the mid east-west point of Parry Sound District. Originally derived from the words, Algonquin, Magnetawan, and Seguin. Almaguin is now used to describe the marketing region of East Parry Sound.
  • 744
  • 01 Dec 2022
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