83 resultados para Cluster structure of atomic nuclei
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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This paper is the result of the Masters dissertation studying the role and history of scientific communication, especially the changes that have occurred after the appearance of electronic communication and computer networks. This study showed that hypertext systems are increasingly being used in the scientific and academic world in the production of electronic journals; this makes it possible for the user to rapidly access information in their area. However, these systems need to be improved to help the user during search and access to information. Both printed journals migrating to electronic media, and the exclusively electronic journals should present the current quality indicators. The attempt was made to discover whether characteristics related to printed journals are being maintained in their electronic counterparts. For this, a prototype model was developed to analyze the structure of electronic scientific journals; it composes 14 criteria expressing aspects of quality for these journals. It includes elements of Website Information Architecture and those already in place in printed scientific journals in order to ensure that basic functions - archiving and dissemination - are maintained in electronic publishing. Each criterion consists of variables, which measure the maintenance of these functions both in the migrating printed journals and the exclusively electronic ones. This prototype model was used to analyze Ciência da Informação On-line and DataGramaZero - Revista de Ciência da Informação. Results indicate that this model is able to find out if the basic functions of archiving and dissemination are being maintained in electronic journals. Therefore, its implementation is justified in electronic journals. The model can help librarians, authors, and users of electronic journals to identify quality journals, and assist editors in developing their projects. The material from the study may be included in the preservice and inservice education of Information Science professionals and to support editors of scientific journals.
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This study aimed at evaluating the effect of the use of different growth promoters on the morphometry and ultra-structure of the intestinal mucosa of 42-day-old broilers. A total number of 36 male Cobb broilers was distributed in a randomized experimental design with a 3 x 3 factorial arrangement, with 3 prebiotic and 3 probiotic sources in the feed, summing up 9 treatments, with 4 replicates each. There was a significant interaction (P<0.01) among the studied factor for villi height (VH) in all intestinal segments, and for crypt depth (CD) in the duodenum and the ileum. In the duodenum, higher villi were obtained in the control group, with the combination of B. subtilis and prebiotics, and with the single use of MOS+OA. No VH differences were observed between the control group and those fed prebiotics. In the jejunum, the highest villi were obtained with the use of the bacterial pool, followed by the control group, and by the use of B. subtilis. Higher villi were also obtained in the control group and in the groups fed MOS, when B. subtilis was used in combination with prebiotics, and when the bacterial pool was used individually or in combination with MOS. In the ileum, the highest villi were obtained with the individual use of B. subtilis, and when MOS+OA or MOS were individually used or in combination with the bacterial pool. As to duodenal CID, deeper crypts were observed in the control group and in those fed B. subtilis or MOS+OA. In the ileum, deeper crypts were also found in the control group and those fed B. subtilis. Deeper crypts were also found when the bacterial pool was individually used or in combination with MOS+OA, and with the individual use of MOS. It was concluded that the use of growth promoters was beneficial to Increase intestinal villi height when Bacillus subtilis was used in combination with prebiotics. The other growth promoters (MOS+OA, MOS, and bacterial pool), can be individually used in most situations. The tested growth promoters did not influence intestinal villi density.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)
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The binding selectivity of the M(phen)(edda) (M = Cu, Co, Ni, Zn; phen = 1,10-phenanthroline, edda = ethylenediaminediacetic acid) complexes towards ds(CG)(6), ds(AT)(6) and ds(CGCGAATTCGCG) B-form oligonucleotide duplexes were studied by CD spectroscopy and molecular modeling. The binding mode is intercalation and there is selectivity towards AT-sequence and stacking preference for A/A parallel or diagonal adjacent base steps in their intercalation. The nucleolytic properties of these complexes were investigated and the factors affecting the extent of cleavage were determined to be: concentration of complex, the nature of metal(11) ion, type of buffer, pH of buffer, incubation time, incubation temperature, and the presence of hydrogen peroxide or ascorbic acid as exogenous reagents. The fluorescence property of these complexes and its origin were also investigated. The crystal structure of the Zn(phen)(edda) complex is reported in which the zinc atom displays a distorted trans-N4O2 octahedral geometry; the crystal packing features double layers of complex molecules held together by extensive hydrogen bonding that inter-digitate with adjacent double layers via pi...pi interactions between 1,10-phenanthroline residues. The structure is compared with that of the recently described copper(II) analogue and, with the latter, included in molecular modeling. (C) 2008 Elsevier B.V. All rights reserved.