935 resultados para super-dense computation
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The brain-spliced isoform of Myosin Va (BR-MyoVa) plays an important role in the transport of dense core secretory granules (SGs) to the plasma membrane in hormone and neuropeptide-producing cells. The molecular composition of the protein complex that recruits BR-MyoVa to SGs and regulates its function has not been identified to date. We have identified interaction between SG-associated proteins granuphilin-a/b (Gran-a/b), BR-MyoVa and Rab27a, a member of the Rab family of GTPases. Gran-a/b-BR-MyoVa interaction is direct, involves regions downstream of the Rab27-binding domain, and the C-terminal part of Gran-a determines exon specificity. MyoVa and Gran-a/b are partially colocalised on SGs and disruption of Gran-a/b-BR-MyoVa binding results in a perinuclear accumulation of SGs which augments nutrient-stimulated hormone secretion in pancreatic beta-cells. These results indicate the existence of at least another binding partner of BR-MyoVa that was identified as rabphilin-3A (Rph-3A). BR-MyoVa-Rph-3A interaction is also direct and enhanced when secretion is activated. The BR-MyoVa-Rph-3A and BR-MyoVa-Gran-a/b complexes are linked to a different subset of SGs, and simultaneous inhibition of these complexes nearly completely blocks stimulated hormone release. This study demonstrates that multiple binding partners of BR-MyoVa regulate SG transport, and this molecular mechanism is universally used by neuronal, endocrine and neuroendocrine cells.
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Ecrit par le copiste Bertrand (f. 170v).
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Error-correcting codes and matroids have been widely used in the study of ordinary secret sharing schemes. In this paper, the connections between codes, matroids, and a special class of secret sharing schemes, namely, multiplicative linear secret sharing schemes (LSSSs), are studied. Such schemes are known to enable multiparty computation protocols secure against general (nonthreshold) adversaries.Two open problems related to the complexity of multiplicative LSSSs are considered in this paper. The first one deals with strongly multiplicative LSSSs. As opposed to the case of multiplicative LSSSs, it is not known whether there is an efficient method to transform an LSSS into a strongly multiplicative LSSS for the same access structure with a polynomial increase of the complexity. A property of strongly multiplicative LSSSs that could be useful in solving this problem is proved. Namely, using a suitable generalization of the well-known Berlekamp–Welch decoder, it is shown that all strongly multiplicative LSSSs enable efficient reconstruction of a shared secret in the presence of malicious faults. The second one is to characterize the access structures of ideal multiplicative LSSSs. Specifically, the considered open problem is to determine whether all self-dual vector space access structures are in this situation. By the aforementioned connection, this in fact constitutes an open problem about matroid theory, since it can be restated in terms of representability of identically self-dual matroids by self-dual codes. A new concept is introduced, the flat-partition, that provides a useful classification of identically self-dual matroids. Uniform identically self-dual matroids, which are known to be representable by self-dual codes, form one of the classes. It is proved that this property also holds for the family of matroids that, in a natural way, is the next class in the above classification: the identically self-dual bipartite matroids.
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Dense granular bodies (DGB) are particular structural constituents observed in cell nuclei of different tissues-liver, pancreas, brown adipose tissue, adrenal cortex-of hibernating dormice. They appear as strongly electron-dense clusters of closely packed granules, with thin fibrils spreading out at their periphery. DGB always occur in the nucleoplasm, sometimes making contact with other nuclear structural constituents typical of the hibernating state, such as coiled bodies, amorphous bodies and nucleoplasmic fibrils. DGB are present only during deep hibernation and rapidly disappear upon arousal from hibernation. Cytochemical and immunocytochemical analyses showed that DGB contain ribonucleoproteins and several nucleoplasmic RNA processing factors, suggesting that DGB can represent accumulation sites of splicing factors which are provided to splicing sites when normal metabolic activity is rapidly restored during arousal.
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Ex-libris "S. Cornelii Compendiensis Congr. S. Mauri", suivi du chiffre 91B, XVIIe s., f. 1. Compiègne.
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Cordeliers.
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Jacobins de la rue Saint-Honoré.
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Collection : French books before 1601 ; 66.1
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Collection : Italian books before 1601 ; 59.5
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Franc. Philelfi orationes (34). - Philelfus Francisco Sforcie (92). - Guarinus Veron. Conrado Alcaldo (96). - De matrimonio inter Stephanum Salvanum et Margaritam Pontam (96 v°). - Plutarchus, de liberis educandis, interprete Garino Veron. (101).
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The generalization of simple correspondence analysis, for two categorical variables, to multiple correspondence analysis where they may be three or more variables, is not straighforward, both from a mathematical and computational point of view. In this paper we detail the exact computational steps involved in performing a multiple correspondence analysis, including the special aspects of adjusting the principal inertias to correct the percentages of inertia, supplementary points and subset analysis. Furthermore, we give the algorithm for joint correspondence analysis where the cross-tabulations of all unique pairs of variables are analysed jointly. The code in the R language for every step of the computations is given, as well as the results of each computation.
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Astrocytes are the brain nonnerve cells that are competent for gliosecretion, i.e., for expression and regulated exocytosis of clear and dense-core vesicles (DCVs). We investigated whether expression of astrocyte DCVs is governed by RE-1-silencing transcription factor (REST)/neuron-restrictive silencer factor (NRSF), the transcription repressor that orchestrates nerve cell differentiation. Rat astrocyte cultures exhibited high levels of REST and expressed neither DCVs nor their markers (granins, peptides, and membrane proteins). Transfection of a dominant-negative construct of REST induced the appearance of DCVs filled with secretogranin 2 and neuropeptide Y (NPY) and distinct from other organelles. Total internal reflection fluorescence analysis revealed NPY-monomeric red fluorescent protein-labeled DCVs to undergo Ca(2+)-dependent exocytosis, which was largely prevented by botulinum toxin B. In the I-II layers of the human temporal brain cortex, all neurons and microglia exhibited the expected inappreciable and high levels of REST, respectively. In contrast, astrocyte REST was variable, going from inappreciable to high, and accompanied by a variable expression of DCVs. In conclusion, astrocyte DCV expression and gliosecretion are governed by REST. The variable in situ REST levels may contribute to the well-known structural/functional heterogeneity of astrocytes.
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O presente trabalho intitula-se «Controlo Interno como suporte estratégico na Gestão das Empresas», pressupõe que todas as instituições devem ter um departamento de controlo interno para que possam desempenhar as suas actividades com eficiência e eficácia para alcançarem os objectivos estabelecidos pela administração. Porem, este trabalho teve como o principal objectivo definir e ampliar uma visão da importância do controlo interno nas instituições, pondo o foco no estudo de caso do Grupo Calú & Ângela, e Palácio Finícia. O controlo interno define-se como um conjunto de normas, procedimentos, instrumentos e acções utilizados pelas instituições ou empresas de uma forma sistematizada com o objectivo de assegurar o comprimento das normas e regulamentos internos.Partindo do pressuposto que, o controlo interno é uma ferramenta essencial para a gestão das instituições que prima pela salvaguarda dos seus activos e de prever eventuais riscos que possa pôr em causa a credibilidade das instituições, como, fraude, receptação de mercadorias diteoradas e fora do prazo, essas empresas devem ter um sistema de controlo interno robusta capaz de detectar essas situações constrangedoras. Portanto, os objectivos traçados e alcançados no trabalho é de uma interacção com o quotidiano das empresas comerciais em cabo verde, uma aproximação da teoria aprendida, e a prática desenvolvida durante o estágio curricular que teve uma metodologia virada pela pesquisas bibliográficas, pesquisas na internet, e aplicação do questionário.