The Sea of Okhotsk is a marginal sea of the western Pacific Ocean, between the Kamchatka Peninsula on the east, the Kuril Islands on the southeast, the island of Hokkaido to the south, the island of Sakhalin along the west, a long stretch of eastern Siberian coast along the west and north. The northeast corner is the Shelikhov Gulf; the sea is named after the first Russian settlement in the Far East. The Sea of Okhotsk covers an area of 1,583,000 square kilometres, with a mean depth of 859 metres and a maximum depth of 3,372 metres, it is connected to the Sea of Japan on either side of Sakhalin: on the west through the Sakhalin Gulf and the Gulf of Tartary. In winter, navigation on the Sea of Okhotsk is impeded by ice floes. Ice floes form due to the large amount of freshwater from the Amur River, lowering the salinity of upper levels raising the freezing point of the sea surface; the distribution and thickness of ice floes depends on many factors: the location, the time of year, water currents, the sea temperatures.
Cold air from Siberia forms sea ice sea in the northwestern Sea of Okhotsk. As the ice forms it expels salt into the deeper layers; this heavy water flows east toward the Pacific carrying oxygen and nutrients, supporting abundant sea life. The Sea of Okhotsk has warmed in some places by as much as 3 degrees Celsius since preindustrial times, three times faster than the global mean. Warming inhibits the formation of sea ice and drives fish populations north; the Salmon catch on the northern Japanese coast has fallen 70% in the last 15 years, while the Russian chum salmon catch has quadrupled. With the exception of Hokkaido, one of the Japanese home islands, the sea is surrounded on all sides by territory administered by the Russian Federation; the International Hydrographic Organization defines the limits of the Sea of Okhotsk as follows: On the Southwest. The Northeastern and Northern limits on the Japan Sea. On the Southeast. A line running from Nosyappu Saki in the Island of Hokusyû through the Kuril or Tisima Islands to Cape Lopatka in such a way that all the narrow waters between Hokusyû and Kamchatka are included in the Sea of Okhotsk.
Some of the Sea of Okhotsk's islands are quite large, including Japan's second largest island, Hokkaido, as well as Russia's largest island, Sakhalin. All of the sea's islands are either in coastal waters or belong to the various islands making up the Kuril Islands chain; these fall either under undisputed Japanese or Russian ownership or disputed ownership between Japan and Russia. Iony Island is the only island located in open waters and belongs to the Khabarovsk Krai of the Russian Federation; the majority of the sea's islands are uninhabited making them ideal breeding grounds for seals, sea lions and other sea island fauna. Large colonies, with over a million individuals, of crested auklets use the Sea of Okhotsk as a nesting site; the Okhotsk culture is an archaeological coastal fishing and hunter-gatherer culture of the lands surrounding the Sea of Okhotsk. Some believe. Russian explorers Ivan Moskvitin and Vassili Poyarkov were the first Europeans to visit the Sea of Okhotsk in the 1640s.
The Dutch captain Maarten Gerritsz Vries in the Breskens entered the Sea of Okhotsk from the south-east in 1643, charted parts of the Sakhalin coast and Kurile Islands, but failed to realize that either Sakhalin or Hokkaido are islands. The first and foremost Russian settlement on the shore was the port of Okhotsk, which relinquished commercial supremacy to Ayan in the 1840s; the Russian-American Company all but monopolized the commercial navigation of the sea in the first half of the 19th century. The Second Kamchatka Expedition under Vitus Bering systematically mapped the entire coast of the sea, starting in 1733. Jean-François de La Pérouse and William Robert Broughton were the first non-Russian European navigators known to have passed through these waters other than Maarten Gerritsz Vries. Ivan Krusenstern explored the eastern coast of Sakhalin in 1805. Mamiya Rinzō and Gennady Nevelskoy determined that the Sakhalin was indeed an island separated from the mainland by a narrow strait; the first detailed summary of the hydrology of the Okhotsk sea was prepared and published by Stepan Makarov in 1894.
The Sea of Okhotsk is one of the world's richest in biological resources, with various kinds of fish and crabs. The harsh conditions of crab fishing in the Sea of Okhotsk is the subject of the most famous novel of the Japanese writer Takiji Kobayashi, The Crab Cannery Ship. American and European whaleships hunted whales in the sea in the nineteenth and early twentieth centuries, they caught right and bowhead whales. A number of ships were wrecked in the sea. During the Cold War, the Sea of Okhotsk was the scene of several successful U. S. Navy operations to tap Soviet Navy undersea communications cables; these operations were documented in the book Blind Man's Bluff: The Untold Story of American Submarine Espionage. The sea were the scene of the Soviet attack on Korean Air Flight 007 in 1983; the Soviet Pacific Fleet used the Sea as a ballistic missile submarine bastion, a strategy that Russia continues. In the Japanese language, the sea has no traditional Japanes
Derry Ormond railway station served the hamlet and rural locale of Betws Bledrws near Llangybi, as well as the mansion and estate of Derry Ormond on the Carmarthen Aberystwyth Line in the Welsh county of Ceredigion. Opened in 1867 as Bettws, it was renamed in July 1874 in honour of the local estate, owned by the influential Jones Inglis-Jones, family; the Manchester and Milford Railway opened from Pencader to Aberystwyth on 12 August 1867. The line went into receivership from 1875 to 1900; the Great Western Railway took over the service in 1906, absorbed the line in 1911. The Great Western Railway and the station passed on to British Railways on nationalisation in 1948, it was closed by the British Railways Board. The OS maps and photographs show that it had one platform, a signal box, a weighing machine, a siding. A passing loop was located just beyond the Llangybi end of the single platform. Passenger services ran through to Aberystwyth until flooding damaged the line south of Aberystwyth in December 1964.
A limited service continued running from Carmarthen to Tregaron for a few months after the line was severed, however this was the era of the Beeching Axe and the line was closed to passengers in February 1965. The line remained open for milk traffic until 1970; the corrugated iron station buildings are a remarkable survival of a small station little altered since Great Western Railway, in GWR colours, which served the combined function of waiting room and ticket office. Notes SourcesButt, R. V. J.. The Directory of Railway Stations: details every public and private passenger station, halt and stopping place and present. Sparkford: Patrick Stephens Ltd. ISBN 978-1-85260-508-7. OCLC 60251199. Jowett, Alan. Jowett's Nationalised Railway Atlas. Penryn, Cornwall: Atlantic Transport Publishers. ISBN 978-0-906899-99-1. OCLC 228266687. Jowett, Alan. Jowett's Railway Atlas of Great Britain and Ireland: From Pre-Grouping to the Present Day. Sparkford: Patrick Stephens Ltd. ISBN 978-1-85260-086-0. OCLC 22311137. Archive Images
Caulobacter crescentus is a Gram-negative, oligotrophic bacterium distributed in fresh water lakes and streams. Caulobacter is an important model organism for studying the regulation of the cell cycle, asymmetric cell division, cellular differentiation. Caulobacter daughter cells have two different forms. One daughter is a mobile "swarmer" cell that has a single flagellum at one cell pole that provides swimming motility for chemotaxis; the other daughter, called the "stalked" cell, has a tubular stalk structure protruding from one pole that has an adhesive holdfast material on its end, with which the stalked cell can adhere to surfaces. Swarmer cells differentiate into stalked cells after a short period of motility. Chromosome replication and cell division only occurs in the stalked cell stage, its name derives from its crescent shape caused by the protein crescentin, discovered by Christine Jacobs-Wagner's laboratory. Its use as a model originated with developmental biologist Lucy Shapiro. In the laboratory, researchers distinguish between C. crescentus strain CB15 and NA1000.
In strain NA1000, derived from CB15 in the 1970s, the stalked and predivisional cells can be physically separated in the laboratory from new swarmer cells, while cell types from strain CB15 cannot be physically separated. The isolated swarmer cells can be grown as a synchronized cell culture. Detailed study of the molecular development of these cells as they progress through the cell cycle has enabled researchers to understand Caulobacter cell cycle regulation in great detail. Due to this capacity to be physically synchronized, strain NA1000 has become the predominant experimental Caulobacter strain throughout the world. Additional phenotypic differences between the two strains have subsequently accumulated due to selective pressures on the NA1000 strain in the laboratory environment; the genetic basis of the phenotypic differences between the two strains results from coding and insertion/deletion polymorphisms at five chromosomal loci. C. crescentus is synonymous with Caulobacter vibrioides.
The Caulobacter CB15 genome has 4,016,942 base pairs in a single circular chromosome encoding 3,767 genes. The genome contains multiple clusters of genes encoding proteins essential for survival in a nutrient-poor habitat. Included are those involved in chemotaxis, outer membrane channel function, degradation of aromatic ring compounds, the breakdown of plant-derived carbon sources, in addition to many extracytoplasmic function sigma factors, providing the organism with the ability to respond to a wide range of environmental fluctuations. In 2010, the Caulobacter NA1000 strain was sequenced and all differences with the CB15 "wild type" strain were identified; the Caulobacter stalked cell stage provides a fitness advantage by anchoring the cell to surfaces to form biofilms and or to exploit nutrient sources. The bacterial species that divides fastest will be most effective at exploiting resources and occupying ecological niches. Yet, Caulobacter has the swarmer cell stage. What is the offsetting fitness advantage of this motile cell stage?
The swarmer cell is thought to provide cell dispersal, so that the organism seeks out new environments. This may be useful in nutrient-limited environments when the scant resources available can be depleted quickly. Many most, of the swarmer daughter cells will not find a productive environment, but the obligate dispersal stage must increase the reproductive fitness of the species as a whole; the Caulobacter cell cycle regulatory system controls many modular subsystems that organize the progression of cell growth and reproduction. A control system constructed using biochemical and genetic logic circuitry organizes the timing of initiation of each of these subsystems; the central feature of the cell cycle regulation is a cyclical genetic circuit—a cell cycle engine –-, centered around the successive interactions of five master regulatory proteins: DnaA, GcrA, CtrA, SciP, CcrM whose roles were worked out by Lucy Shapiro's laboratory. These five proteins directly control the timing of expression of over 200 genes.
The five master regulatory proteins are synthesized and eliminated from the cell one after the other over the course of the cell cycle. Several additional cell signaling pathways are essential to the proper functioning of this cell cycle engine; the principal role of these signaling pathways is to ensure reliable production and elimination of the CtrA protein from the cell at just the right times in the cell cycle. An essential feature of the Caulobacter cell cycle is that the chromosome is replicated once and only once per cell cycle; this is in contrast to the E. coli cell cycle where there can be overlapping rounds of chromosome replication underway. The opposing roles of the Caulobacter DnaA and CtrA proteins are essential to the tight control of Caulobacter chromosome replication; the DnaA protein acts at the origin of replication to initiate the replication of the chromosome. The CtrA protein, in contrast, acts to block initiation of replication, so it must be removed from the cell before chromosome replication can begin.
Multiple additional regulatory pathways integral to cell cycle regulation and involving both phospho signaling pathways and regulated control of protein proteolysis act to assure that DnaA and CtrA are present in the cell just when needed. Each process activated by the proteins of the cell cycle engine involve a cascade of many reactions; the longest subsystem cascade is DNA replication. In Caulobacter cells, replication of the chromosome involves about 2 mill