1,259 research outputs found

    Subject-access metadata on ETD supplied by authors: A case study about keywords, titles and abstracts in a Brazilian academic repository

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    The keyword lists are rich in terminology and as such, they are also characterized by great semantic ambiguity, which presents the problems of synonymy and polysemy typical of uncontrolled language, which is both an advantage and a drawback. However, assigning keywords has gained particular importance in the current open scientific communication ecosystem in digital environments, mainly in the academic dissertation and repositories of theses. This article reports a study on the organization of knowledge, using subject-access metadata of master''s theses from the digital repository of the University of São Paulo (USP), Brazil, applying analytical techniques to a big amount of data. The objective was to analyze the number of keywords in each record and keywords repeated in the title and abstracts of the dissertations in Portuguese and English. The analysis of the 48, 501 metadata records of master''s theses submitted to the repository, between 2001 and 2019, presents a total of 223, 867 keywords in Portuguese, with an average of 4.62 keywords per record, and a total of 216, 521 keywords in English, equivalent to an average of 4.59 per record. Although, the attribution of keywords in Portuguese and English by the author is an economic way to expand access to the content of theses and dissertations in institutional repositories, it is necessary to define rules for authors about the choice of keywords and the preparation of the abstract, as well as its translation into English. The task of controlling keywords requires a partnership between authors and librarians who can enrich the quality of indexing languages

    Geometrically induced singular behavior of entanglement

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    We show that the geometry of the set of quantum states plays a crucial role in the behavior of entanglement in different physical systems. More specifically it is shown that singular points at the border of the set of unentangled states appear as singularities in the dynamics of entanglement of smoothly varying quantum states. We illustrate this result by implementing a photonic parametric down conversion experiment. Moreover, this effect is connected to recently discovered singularities in condensed matter models.Comment: v2: 4 pags, 4 figs. A discussion before the proof of Proposition 1 and tomographic results were included, Propostion 2 was removed and the references were fixe

    Physiological characterization of common bean (Phaseolus vulgaris L.) genotypes, water-stress induced with contrasting response towards drought.

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    Among the three annual common bean seasons in Brazil, two of them are subject to drought. The objective of this study was to identify physiological traits in common bean under water restriction. The common beans genotypes, BAT 477 (tolerant to water-stress) and Perola (sensitive to water-stress), were grown under greenhouse conditions under two different watering regimes: irrigated (control treatment) and non-irrigated (stress treatment). The water deficit treatment consisted of suspension of irrigation to the plants at 10 days after emergence (DAE) (at the V2 physiological stage) for 30 days, followed by the irrigation?s re-establishment at 40 DAE (at the R6-R7 physiological stage) up to the phase of physiological maturity of the grains for assessment of grain yield and production components. Under water-stress, BAT 477 showed less reduction in grain yield (33%), more capacity for osmotic adjustment (0.30 MPa) and superiority in the root system´s development (~50%) compared to Perola that showed a 53% reduction in the grain yield and 0.06 MPa of osmotic adjustment. In this study, the robustness of the root system and osmotic adjustment are the main physiological indicators of tolerance to water deficit in common bean plants
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