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Ascomycota
Ascomycota is a phylum of the kingdom Fungi that, together with the Basidiomycota, forms the subkingdom Dikarya. Its members are commonly known as the sac fungi or ascomycetes. It is the largest phylum of Fungi, with over 64,000 species. The defining feature of this fungal group is the "ascus" (from grc ἀσκός (askós) 'sac, wineskin'), a microscopic sexual structure in which nonmotile spores, called ascospores, are formed. However, some species of the Ascomycota are asexual, meaning that they do not have a sexual cycle and thus do not form asci or ascospores. Familiar examples of sac fungi include morels, truffles, brewers' and bakers' yeast, dead man's fingers, and cup fungi. The fungal symbionts in the majority of lichens (loosely termed "ascolichens") such as Cladonia belong to the Ascomycota. Ascomycota is a monophyletic group (it contains all descendants of one common ancestor). Previously placed in the Deuteromycota along with asexual species from other fungal taxa, asexual (or anamorphic) ascomycetes are now identified and classified based on morphological or physiological similarities to ascus-bearing taxa, and by phylogenetic analyses of DNA sequences. The ascomycetes are of particular use to humans as sources of medicinally important compounds, such as antibiotics, for fermenting bread, alcoholic beverages and cheese. Penicillium species on cheeses and those producing antibiotics for treating bacterial infectious diseases are examples of ascomycetes. Many ascomycetes are pathogens, both of animals, including humans, and of plants. Examples of ascomycetes that can cause infections in humans include Candida albicans, Aspergillus niger and several tens of species that cause skin infections. The many plant-pathogenic ascomycetes include apple scab, rice blast, the ergot fungi, black knot, and the powdery mildews. Several species of ascomycetes are biological model organisms in laboratory research. Most famously, Neurospora crassa, several species of yeasts, and Aspergillus species are used in many genetics and cell biology studies.
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  • 04 Nov 2022
Topic Review
Partition (Number Theory)
In number theory and combinatorics, a partition of a positive integer n, also called an integer partition, is a way of writing n as a sum of positive integers. Two sums that differ only in the order of their summands are considered the same partition. (If order matters, the sum becomes a composition.) For example, 4 can be partitioned in five distinct ways: 4 3 + 1 2 + 2 2 + 1 + 1 1 + 1 + 1 + 1 The order-dependent composition 1 + 3 is the same partition as 3 + 1, and the two distinct compositions 1 + 2 + 1 and 1 + 1 + 2 represent the same partition 2 + 1 + 1. A summand in a partition is also called a part. The number of partitions of n is given by the partition function p(n). So p(4) = 5. The notation λ ⊢ n means that λ is a partition of n. Partitions can be graphically visualized with Young diagrams or Ferrers diagrams. They occur in a number of branches of mathematics and physics, including the study of symmetric polynomials and of the symmetric group and in group representation theory in general.
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  • 04 Nov 2022
Topic Review
Landtag
A Landtag (State Diet) is a representative assembly (parliament) in German-speaking countries with legislative authority and competence over a federated state (Land). Landtage assemblies are the legislative bodies for the individual states of Germany and states of Austria, and have authority to legislate in non-federal matters for the regional area. Likewise, the Landtag of South Tyrol (Italian: Consiglio della Provincia autonoma di Bolzano) is the legislature of the autonomous province of South Tyrol in northeast Italy. In the sovereign principality of Liechtenstein the national parliament is called the Landtag of Liechtenstein.
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  • 04 Nov 2022
Topic Review
Ras Subfamily
Ras is a family of related proteins which is expressed in all animal cell lineages and organs. All Ras protein family members belong to a class of protein called small GTPase, and are involved in transmitting signals within cells (cellular signal transduction). Ras is the prototypical member of the Ras superfamily of proteins, which are all related in 3D structure and regulate diverse cell behaviours. When Ras is 'switched on' by incoming signals, it subsequently switches on other proteins, which ultimately turn on genes involved in cell growth, differentiation and survival. Mutations in ras genes can lead to the production of permanently activated Ras proteins. As a result, this can cause unintended and overactive signaling inside the cell, even in the absence of incoming signals. Because these signals result in cell growth and division, overactive Ras signaling can ultimately lead to cancer. The 3 Ras genes in humans (HRas, KRas, and NRas) are the most common oncogenes in human cancer; mutations that permanently activate Ras are found in 20% to 25% of all human tumors and up to 90% in certain types of cancer (e.g., pancreatic cancer). For this reason, Ras inhibitors are being studied as a treatment for cancer and other diseases with Ras overexpression.
  • 1.5K
  • 04 Nov 2022
Topic Review
Lexis
In linguistics, lexis describes the storage of language in our mental Lexicon as prefabricated patterns that can be recalled and sorted into meaningful speech and writing. Recent research in corpus linguistics suggests that the long-held dichotomy between grammar and vocabulary does not exist. Lexis as a concept differs from the traditional paradigm of grammar in that it defines probable language use, not possible language usage. This notion contrasts starkly with the Chomskian proposition of a “Universal Grammar” as the prime mover for language; grammar still plays an integral role in lexis, of course, but it is the result of accumulated lexis, not its generator. In short, the Lexicon is • Formulaic: it relies on partially-fixed expressions and highly probable word combinations • Idiomatic: it follows conventions and patterns for usage • Metaphoric: concepts such as time and money, business and sex, systems and water all share a large portion of the same vocabulary • Grammatical: it uses rules based on sampling of the Lexicon • Register-specific: it uses the same word differently and/or less frequently in different contexts
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  • 04 Nov 2022
Topic Review
Diamond DA40
The Diamond DA40 Star is an Austrian four-seat, single-engine, light aircraft constructed from composite materials. Built in both Austria and Canada, it was developed as a four-seat version of the earlier DA20 by Diamond Aircraft Industries.
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  • 04 Nov 2022
Topic Review
3D City Models
3D city models are digital models of urban areas that represent terrain surfaces, sites, buildings, vegetation, infrastructure and landscape elements in three-dimensional scale as well as related objects (e.g., city furniture) belonging to urban areas. Their components are described and represented by corresponding two-dimensional and three-dimensional spatial data and geo-referenced data. 3D city models support presentation, exploration, analysis, and management tasks in a large number of different application domains. In particular, 3D city models allow "for visually integrating heterogeneous geoinformation within a single framework and, therefore, create and manage complex urban information spaces."
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  • 04 Nov 2022
Topic Review
Electrical Contacts
An electrical contact is an electrical circuit component found in electrical switches, relays, connectors and circuit breakers. Each contact is a piece of electrically conductive material, typically metal. When a pair of contacts touch, they can pass an electrical current with a certain contact resistance, dependent on surface structure, surface chemistry and contact time; when the pair is separated by an insulating gap, then the pair does not pass a current. When the contacts touch, the switch is closed; when the contacts are separated, the switch is open. The gap must be an insulating medium, such as air, vacuum, oil, SF6. Contacts may be operated by humans in push-buttons and switches, by mechanical pressure in sensors or machine cams, and electromechanically in relays. The surfaces where contacts touch are usually composed of metals such as silver or gold alloys that have high electrical conductivity, wear resistance, oxidation resistance and other properties.
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  • 04 Nov 2022
Topic Review
Galvanic Anode
A galvanic anode, or sacrificial anode, is the main component of a galvanic cathodic protection (CP) system used to protect buried or submerged metal structures from corrosion. They are made from a metal alloy with a more "active" voltage (more negative reduction potential / more positive electrode potential) than the metal of the structure. The difference in potential between the two metals means that the galvanic anode corrodes, so that the anode material is consumed in preference to the structure. The loss (or sacrifice) of the anode material gives rise to the alternative name of sacrificial anode.
  • 1.1K
  • 08 Nov 2022
Topic Review
Mercedes-Benz CLS-Class (W219)
The C219 Mercedes-Benz CLS-Class is the first generation of the CLS-Class range of four-door coupe features a fastback body style by Mercedes-Benz, and was produced between 2004 and 2010. The CLS-Class has only four seats and is marketed by Mercedes as a four-door coupé. For this reason, in Germany and in whole Europe the model code name is C219 while in US the CLS is more commonly named as W219 model. It was the first model globally to introduce this four-door coupe style and VW followed with the Volkswagen CC model in 2008. The car is less practical than the W211 E-Class that it is based on, with less legroom, headroom, and boot space. The CLS-Class is priced above the E-Class, but below the S-Class in the Mercedes model range. It was replaced by the Mercedes-Benz CLS-Class (W218) in 2011.
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  • 04 Nov 2022
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