948 resultados para Hermitian forms
Resumo:
The trimeric human single-stranded DNA-binding protein (HSSB; also called RP-A) plays an essential role in DNA replication, nucleotide excision repair, and homologous DNA recombination. The p34 subunit of HSSB is phosphorylated at the G1/S boundary of the cell cycle or upon exposure of cells to DNA damage-inducing agents including ionizing and UV radiation. We have previously shown that the phosphorylation of p34 is catalyzed by both cyclin-dependent kinase-cyclin A complex and DNA-dependent protein kinase. In this study, we investigated the effect of phosphorylation of p34 by these kinases on the replication and repair function of HSSB. We observed no significant difference with the unphosphorylated and phosphorylated forms of HSSB in the simian virus 40 DNA replication or nucleotide excision repair systems reconstituted with purified proteins. The phosphorylation status of the p34 subunit of HSSB was unchanged during the reactions. We suggest that the phosphorylated HSSB has no direct effect on the basic mechanism of DNA replication and nucleotide excision repair reactions in vitro, although we cannot exclude a role of p34 phosphorylation in modulating HSSB function in vivo through a yet poorly understood control pathway in the cellular response to DNA damage and replication.
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Scrapie is a transmissible neurodegenerative disease that appears to result from an accumulation in the brain of an abnormal protease-resistant isoform of prion protein (PrP) called PrPsc. Conversion of the normal, protease-sensitive form of PrP (PrPc) to protease-resistant forms like PrPsc has been demonstrated in a cell-free reaction composed largely of hamster PrPc and PrPsc. We now report studies of the species specificity of this cell-free reaction using mouse, hamster, and chimeric PrP molecules. Combinations of hamster PrPc with hamster PrPsc and mouse PrPc with mouse PrPsc resulted in the conversion of PrPc to protease-resistant forms. Protease-resistant PrP species were also generated in the nonhomologous reaction of hamster PrPc with mouse PrPsc, but little conversion was observed in the reciprocal reaction. Glycosylation of the PrPc precursors was not required for species specificity in the conversion reaction. The relative conversion efficiencies correlated with the relative transmissibilities of these strains of scrapie between mice and hamsters. Conversion experiments performed with chimeric mouse/hamster PrPc precursors indicated that differences between PrPc and PrPsc at residues 139, 155, and 170 affected the conversion efficiency and the size of the resultant protease-resistant PrP species. We conclude that there is species specificity in the cell-free interactions that lead to the conversion of PrPc to protease-resistant forms. This specificity may be the molecular basis for the barriers to interspecies transmission of scrapie and other transmissible spongiform encephalopathies in vivo.
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This paper outlines the approach adopted by the PLSI research group at University of Alicante in the PASCAL-2006 second Recognising Textual Entailment challenge. Our system is composed of several components. On the one hand, the first component performs the derivation of the logic forms of the text/hypothesis pairs and, on the other hand, the second component provides us with a similarity score given by the semantic relations between the derived logic forms. In order to obtain this score we apply several measures of similitude and relatedness based on the structure and content of WordNet.
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This paper describes a CL-SR system that employs two different techniques: the first one is based on NLP rules that consist on applying logic forms to the topic processing while the second one basically consists on applying the IR-n statistical search engine to the spoken document collection. The application of logic forms to the topics allows to increase the weight of topic terms according to a set of syntactic rules. Thus, the weights of the topic terms are used by IR-n system in the information retrieval process.
Resumo:
As has been the case with other European languages, Spanish has welcomed the arrival of English words, in spite of all purist efforts to the contrary. Moreover, it has not only adopted and adapted true Anglicisms but it has also created other forms based on English patterns, such mechanisms particularly visible in the fashion jargon in Spanish. In this paper we focus on -ing forms in the Spanish language of fashion, which may at times be genuine Anglicisms (formal or semantic ones) or false Anglicisms (analogical creations, that is, English-looking lexical elements), found in Spanish editions of fashion magazines such as Vogue, Elle, InStyle, Grazia, Glamour, and Cosmopolitan. The main aim of this study is to qualitatively analyse and classify -ing Anglicisms and false Anglicisms in the aforementioned jargon in order to establish whether the impact of English in the Spanish fashion jargon is so important as to replace native words and expressions.
Fishes, living and fossil : an outline of their forms and probable relationships / by Bashford Dean.
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Thomas Paine's,
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The objective of this research is to present cluster initiative approaches in post industrial regions characterized by similar economic history and challenges, with additional emphasis on their role in promoting innovation among regional businesses. The research is based on a comparison study of two environmental industry clusters: Environmental Technology Cluster (ET) from British West Midlands and ACLIMA from Spanish Basque Country. The study analyzes clusters' design and their role in fostering innovation based on environment industry clusters. In both regions environmental industry clusters represent strong potential for further dynamic development with grow opportunities driven by legislation introduced at EU, national or regional levels. The paper compares clusters' heterogeneity, goals and priorities, financing schemes, management structure, types of projects, character of private-public partnerships, challenges, as well as clusters' collaboration at regional/national/international levels. Also focus is given on how the clusters enhance innovation and what types of projects are executed by the regions in this field.