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Crystal Mush
A crystal mush is a magmatic body which contains a significant amount of crystals (up to 50% of the volume) suspended in the liquid phase (melt). As the crystal fraction makes up less than half of the volume, there is no rigid large-scale three-dimensional network as in solids. As such, their rheological behavior mirrors that of absolute liquids. Within a single crystal mush, there is grading to a higher solid fraction towards the margins of the pluton while the liquid fraction increases towards the uppermost portions, forming a liquid lens at the top. Furthermore, depending on depth of placement crystal mushes are likely to contain a larger portion of crystals at greater depth in the crust than at shallower depth, as melting occurs from the adiabatic decompression of the magma as it rises, this is particularly the case for mid-oceanic ridges. Seismic investigation offers strong evidence for the existence of crystal mushes rather than fully liquid magmatic bodies. Crystal mushes can have a wide range of chemical and mineralogical compositions, from mafic (SiO2-poor, MgO-rich) to felsic (SiO2-rich, MgO-poor).
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  • 01 Dec 2022
Topic Review
DNS Zone
A DNS zone is a specific portion of the DNS namespace in the Domain Name System (DNS), which is managed by a specific organization or administrator. A DNS zone is an administrative space that allows for more granular control of the DNS components, such as authoritative nameserver. The DNS is broken up into many different zones, which are distinctly managed areas in the DNS namespace. DNS zones are not necessarily physically separated from one another, however, a DNS zone can contain multiple subdomains and multiple zones can exist on the same server. The domain namespace of the Internet is organized into a hierarchical layout of subdomains below the DNS root domain. The individual domains of this tree may serve as delegation points for administrative authority and management. However, usually, it is furthermore desirable to implement fine-grained boundaries of delegation, so that multiple sub-levels of a domain may be managed independently. Therefore, the domain name space is partitioned into areas (zones) for this purpose. A zone starts at a domain and extends downward in the tree to the leaf nodes or to the top-level of subdomains where other zones start. A DNS zone is implemented in the configuration system of a domain name server. Historically, it is defined in the zone file, an operating system text file that starts with the special DNS record type Start of Authority (SOA) and contains all records for the resources described within the zone. This format was originally used by the Berkeley Internet Name Domain Server (BIND) software package and is defined in RFC 1034 and RFC 1035.
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  • 01 Dec 2022
Topic Review
Humid Subtropical Climate
A humid subtropical climate is a zone of climate characterized by hot, humid summers, and cool to mild winters. These climates normally lie on the southeast side of all continents, generally between latitudes 25° and 35° and are located poleward from adjacent tropical climates. While many subtropical climates tend to be located at or near coastal locations, in some cases they extend inland, most notably in China and the United States , where they exhibit more pronounced seasonal variations and sharper contrasts between summer and winter, as part of a gradient between the more tropical climates of the southern coasts of these countries and the more continental climates of China and the United States ' northern and central regions (localities around the Ohio and Yangtze rivers exhibiting continental influence from the north, compared to climates around the Gulf of Mexico and the South China Sea, which exhibit tropical influence due to their southern coastal positions). The humid subtropical climate classification was officially created under the Trewartha Climate classification. Trewartha attempted to redefine middle latitude climates in the Koppen system since many climatologists argued that his "C" climate zone was too broad. Trewartha attempted to separate the middle latitude in three zones (subarctic, temperate, and subtropical). In this classification, climates are termed humid subtropical when they have at least 8 months with a mean temperature above 10 °C (50 °F). Under the Holdridge life zones classification, the subtropical climates have a biotemperature between the frost or critical temperature line, 16 to 18 °C (61 to 64 °F) (depending on locations in the world) and 24 °C (75 °F), and these climates are humid (or even perhumid or superhumid) when the potential evapotranspiration (PET) ratio (= PET / Precipitation) is less than 1. In the Holdridge classification, the humid subtropical climates coincide more or less with the warmest Cfa and Cwa climates and the less warm humid tropical "Köppen" climates (Aw, Am and Af). In a humid subtropical climate, summers are typically long, hot and humid. Monthly mean summer temperatures are normally between 24 and 27 °C (75 and 81 °F). A deep current of tropical air dominates the humid subtropics at the time of high sun, and daily intense (but brief) convective thundershowers are common. Summer high temperatures are typically in the high 20s to mid-30s °C (80s or 90s °F), while overnight lows in the summer are typically in the lower 20s °C (70s °F). Monthly mean temperatures in winter are often mild, typically averaging 7.5 to 16 °C (45.5 to 60.8 °F). Daytime highs in winter normally are in the 10 to 16 °C (50 to 61 °F) range, while overnight lows are from 2 to 7 °C (36 to 45 °F), though the poleward boundaries of this climate feature colder temperatures. Rainfall often shows a summer peak, especially where monsoons are well developed, as in Southeast Asia and South Asia. Other areas have a more uniform or varying rainfall cycles, but consistently lack any predictably dry summer months. Most summer rainfall occurs during thunderstorms that build up due to the intense surface heating and strong subtropical sun angle. Weak tropical lows that move in from adjacent warm tropical oceans, as well as infrequent tropical storms often contribute to summer seasonal rainfall peaks. Winter rainfall is often associated with large storms in the westerlies that have fronts that reach down into subtropical latitudes. However, many subtropical climates such as southeast Asia and Florida in the United States have very dry winters, with frequent brush fires and water shortages.
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  • 01 Dec 2022
Biography
Barbara Jacak
Barbara Jacak is a nuclear physicist who uses heavy ion collisions for fundamental studies of hot, dense nuclear matter. She is Director of the Nuclear Science Division, Lawrence Berkeley National Laboratory, and a professor of Physics at UC Berkeley.[1] Before going to Berkeley, she was a member of the Department of Physics and Astronomy at Stony Brook University, where she held the rank of Dis
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  • 06 Dec 2022
Topic Review
Chemical-Mechanical Planarization
Chemical mechanical polishing/planarization is a process of smoothing surfaces with the combination of chemical and mechanical forces. It can be thought of as a hybrid of chemical etching and free abrasive polishing.
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  • 01 Dec 2022
Topic Review
Sigma-Algebra
In mathematical analysis and in probability theory, a σ-algebra (also σ-field) on a set X is a collection Σ of subsets of X that includes the empty subset, is closed under complement, and is closed under countable unions and countable intersections. The pair (X, Σ) is called a measurable space or Borel space. A σ-algebra is a type of algebra of sets. An algebra of sets needs only to be closed under the union or intersection of finitely many subsets, which is a weaker condition. The main use of σ-algebras is in the definition of measures; specifically, the collection of those subsets for which a given measure is defined is necessarily a σ-algebra. This concept is important in mathematical analysis as the foundation for Lebesgue integration, and in probability theory, where it is interpreted as the collection of events which can be assigned probabilities. Also, in probability, σ-algebras are pivotal in the definition of conditional expectation. In statistics, (sub) σ-algebras are needed for the formal mathematical definition of a sufficient statistic, particularly when the statistic is a function or a random process and the notion of conditional density is not applicable. If X = {a, b, c, d}, one possible σ-algebra on X is Σ = { ∅, {a, b}, {c, d}, {a, b, c, d} }, where ∅ is the empty set. In general, a finite algebra is always a σ-algebra. If {A1, A2, A3, …} is a countable partition of X then the collection of all unions of sets in the partition (including the empty set) is a σ-algebra. A more useful example is the set of subsets of the real line formed by starting with all open intervals and adding in all countable unions, countable intersections, and relative complements and continuing this process (by transfinite iteration through all countable ordinals) until the relevant closure properties are achieved (a construction known as the Borel hierarchy).
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  • 01 Dec 2022
Topic Review
RBS-15
The RBS-15 (Robotsystem 15) is a long-range fire-and-forget surface-to-surface and air-to-surface anti-ship missile. The later version Mk. III has the ability to attack land targets as well. The missile was developed by the Swedish company Saab Bofors Dynamics.
  • 3.7K
  • 01 Dec 2022
Biography
Carl H. Brans
Carl Henry Brans (/brænz/; born December 13, 1935) is an American mathematical physicist best known for his research into the theoretical underpinnings of gravitation elucidated in his most widely publicized work, the Brans–Dicke theory. A Texas , born in Dallas, Carl Brans spent his academic career in neighboring Louisiana, graduating in 1957 from Loyola University New Orleans. Having obt
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  • 01 Dec 2022
Biography
Roy Spencer
Roy Warren Spencer (born December 20, 1955)[1] is a meteorologist,[2] a principal research scientist at the University of Alabama in Huntsville, and the U.S. Science Team leader for the Advanced Microwave Scanning Radiometer (AMSR-E) on NASA's Aqua satellite.[3][4] He has served as senior scientist for climate studies at NASA's Marshall Space Flight Center.[3][4] He is known for his satellite-b
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  • 06 Dec 2022
Topic Review
Beta-Catenin
Catenin beta-1, also known as β-catenin, is a protein that in humans is encoded by the CTNNB1 gene. β-catenin is a dual function protein, involved in regulation and coordination of cell–cell adhesion and gene transcription. In humans, the CTNNB1 protein is encoded by the CTNNB1 gene. In Drosophila, the homologous protein is called armadillo. β-catenin is a subunit of the cadherin protein complex and acts as an intracellular signal transducer in the Wnt signaling pathway. It is a member of the catenin protein family and homologous to γ-catenin, also known as plakoglobin. Beta-catenin is widely expressed in many tissues. In cardiac muscle, beta-catenin localizes to adherens junctions in intercalated disc structures, which are critical for electrical and mechanical coupling between adjacent cardiomyocytes. Mutations and overexpression of β-catenin are associated with many cancers, including hepatocellular carcinoma, colorectal carcinoma, lung cancer, malignant breast tumors, ovarian and endometrial cancer. Alterations in the localization and expression levels of beta-catenin have been associated with various forms of heart disease, including dilated cardiomyopathy. β-catenin is regulated and destroyed by the beta-catenin destruction complex, and in particular by the adenomatous polyposis coli (APC) protein, encoded by the tumour-suppressing APC gene. Therefore, genetic mutation of the APC gene is also strongly linked to cancers, and in particular colorectal cancer resulting from familial adenomatous polyposis (FAP).
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  • 01 Dec 2022
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