8 resultados para Gruppi profiniti, estensioni di Galois, interi p-adici, limiti inversi

em BORIS: Bern Open Repository and Information System - Berna - Suiça


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Gruppo mediatico di proprietà della fam. omonima, le cui origini risalgono alla tipografia fondata nel 1833 a Zofingen da Johann Rudolf (1803-1874). Nel 1898 Paul August Ringier, esponente della terza generazione, rilevò l'azienda, che ampliò fino a farne un'impresa tipografica industriale e una delle principali case editrici della Svizzera. Nel 1932 la Ringier fu trasformata in un gruppo, divenne una soc. anonima e fu fondata la holding. Fino al 1938 pubblicò nove riviste illustrate per fam., di intrattenimento e dedicate ai programmi radiofonici, con una tiratura complessiva di 680'000 copie; nel 1959 diede vita al Blick. Dal 1960 con Hans (1906-2003), figlio di Paul August, e dal 1985 con i suoi figli Christoph (nascita 1941; in azienda fino al 1991) e Michael (nascita 1949), l'impresa divenne il più grande gruppo mediatico della Svizzera. Dal 1980 si è espansa in Germania, Asia e negli Stati Uniti e dal 1992 nell'Europa orientale. Nel 2008 impiegava in tutto il mondo 8129 persone e la cifra d'affari ammontava a oltre 1,535 miliardi di frs. Bibliografia – P. Meier, T. Häussler, Zwischen Masse, Markt und Macht, 2009

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The development of a completely annotated sheep genome sequence is a key need for understanding the phylogenetic relationships and genetic diversity among the many different sheep breeds worldwide and for identifying genes controlling economically and physiologically important traits. The ovine genome sequence assembly will be crucial for developing optimized breeding programs based on highly productive, healthy sheep phenotypes that are adapted to modern breeding and production conditions. Scientists and breeders around the globe have been contributing to this goal by generating genomic and cDNA libraries, performing genome-wide and trait-associated analyses of polymorphism, expression analysis, genome sequencing, and by developing virtual and physical comparative maps. The International Sheep Genomics Consortium (ISGC), an informal network of sheep genomics researchers, is playing a major role in coordinating many of these activities. In addition to serving as an essential tool for monitoring chromosome abnormalities in specific sheep populations, ovine molecular cytogenetics provides physical anchors which link and order genome regions, such as sequence contigs, genes and polymorphic DNA markers to ovine chromosomes. Likewise, molecular cytogenetics can contribute to the process of defining evolutionary breakpoints between related species. The selective expansion of the sheep cytogenetic map, using loci to connect maps and identify chromosome bands, can substantially contribute to improving the quality of the annotated sheep genome sequence and will also accelerate its assembly. Furthermore, identifying major morphological chromosome anomalies and micro-rearrangements, such as gene duplications or deletions, that might occur between different sheep breeds and other Ovis species will also be important to understand the diversity of sheep chromosome structure and its implications for cross-breeding. To date, 566 loci have been assigned to specific chromosome regions in sheep and the new cytogenetic map is presented as part of this review. This review will also summarize the current cytogenomic status of the sheep genome, describe current activities in the sheep cytogenomics research sector, and will discuss the cytogenomics data in context with other major sheep genomics projects.

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We present a new thermodynamic activity-composition model for di-trioctahedral chlorite in the system FeO–MgO–Al2O3–SiO2–H2O that is based on the Holland–Powell internally consistent thermodynamic data set. The model is formulated in terms of four linearly independent end-members, which are amesite, clinochlore, daphnite and sudoite. These account for the most important crystal-chemical substitutions in chlorite, the Fe–Mg, Tschermak and di-trioctahedral substitution. The ideal part of end-member activities is modeled with a mixing-on-site formalism, and non-ideality is described by a macroscopic symmetric (regular) formalism. The symmetric interaction parameters were calibrated using a set of 271 published chlorite analyses for which robust independent temperature estimates are available. In addition, adjustment of the standard state thermodynamic properties of sudoite was required to accurately reproduce experimental brackets involving sudoite. This new model was tested by calculating representative P–T sections for metasediments at low temperatures (<400 °C), in particular sudoite and chlorite bearing metapelites from Crete. Comparison between the calculated mineral assemblages and field data shows that the new model is able to predict the coexistence of chlorite and sudoite at low metamorphic temperatures. The predicted lower limit of the chloritoid stability field is also in better agreement with petrological observations. For practical applications to metamorphic and hydrothermal environments, two new semi-empirical chlorite geothermometers named Chl(1) and Chl(2) were calibrated based on the chlorite + quartz + water equilibrium (2 clinochlore + 3 sudoite = 4 amesite + 4 H2O + 7 quartz). The Chl(1) thermometer requires knowledge of the (Fe3+/ΣFe) ratio in chlorite and predicts correct temperatures for a range of redox conditions. The Chl(2) geothermometer which assumes that all iron in chlorite is ferrous has been applied to partially recrystallized detrital chlorite from the Zone houillère in the French Western Alps.