296 research outputs found

    Evaluation of semantic web ontologies for modelling art collections

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    © 2017, Springer International Publishing AG. The need for organising, sharing and digitally processing Cultural Heritage (CH) information has led to the development of formal knowledge representation models (ontologies) for the CH domain. Based on RDF and OWL, the standard data model and ontology language of the Semantic Web, ontologies such as CIDOC-CRM, the Europeana Data Model and VRA, offer enhanced representation capabilities, but also support for inference, querying and interlinking through the Web. This paper presents the results of a small-scale evaluation of the three most commonly used CH ontologies, with respect to their capacity to fulfil the data modelling requirements of art collections

    SOBRE LOS EVENTOS QUE SE DESATAN CUANDO LA LUZ INCIDE SOBRE UNA NANOESTRUCTURA

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    La interacción de la radiación con la materia es un hecho cotidiano en la naturaleza, se pueden recordar  fenómenos como la fotosíntesis, interacción de la luz solar con las plantas para generar alimento y la generación de la vitamina D en nuestra piel. Con la formación de sistemas masivos, galaxias, estrellas, planetas, en los albores del universo, se establece la radiación electromagnética, la cual se caracteriza por contener ondas con longitudes desde los kilómetros, ondas de radio, hasta longitudes menores que 10-12 m, rayos gama, pasando por la radiación visible detectada por nuestra retina. En este artículo divulgativo, dirigido al público en general, basado en la investigación de Duque et al [1], se va a tratar acerca de los conceptos involucrados en la interacción de la luz con nanoestructuras semiconductoras.The interaction of radiation with matter is an everyday event in nature, we can recall phenomena such as photosynthesis, sunlight interaction with plants to produce food and the generation of vitamin D in our skin. With the formation of massive systems, galaxies, stars, planets, in the early universe, electromagnetic radiation was established, which is characterized by containing wavelengths from the kilometer radio waves to shorter lengths 10-12 m, gamma rays, through visible radiation detected by the retina. In this informative article, for the general public, based on the work by Duque et al [1], the objective is to describe the concepts involved in the interaction of light with semiconductor nanostructures

    Hemoglobin Mass, Blood Volume and VO₂max of Trained and Untrained Children and Adolescents Living at Different Altitudes

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    Introduction: To a considerable extent, the magnitude of blood volume (BV) and hemoglobin mass (Hbmass) contribute to the maximum O(2)-uptake (VO(2)max), especially in endurance-trained athletes. However, the development of Hbmass and BV and their relationships with VO(2)max during childhood are unknown. The aim of the present cross-sectional study was to investigate Hbmass and BV and their relationships with VO(2)max in children and adolescents. In addition, the possible influence of endurance training and chronic hypoxia was evaluated. Methods: A total of 475 differently trained children and adolescents (girls n = 217, boys n = 258; untrained n = 171, endurance trained n = 304) living at two different altitudes (∼1,000 m, n = 204, ∼2,600 m, n = 271) and 9–18 years old participated in the study. The stage of puberty was determined according to Tanner; Hbmass and BV were determined by CO rebreathing; and VO(2)max was determined by cycle ergometry and for runners on the treadmill. Results: Before puberty, there was no association between training status and Hbmass or BV. During and after puberty, we found 7–10% higher values in the trained groups. Living at a moderate altitude had a uniformly positive effect of ∼7% on Hbmass in all groups and no effect on BV. The VO(2)max before, during and after puberty was strongly associated with training (pre/early puberty: boys +27%, girls +26%; mid puberty: +42% and +45%; late puberty: +43% and +47%) but not with altitude. The associated effects of training in the pre/early pubertal groups were independent of Hbmass and BV, while in the mid- and late pubertal groups, 25% of the training effect could be attributed to the elevated Hbmass. Conclusions: The associated effects of training on Hbmass and BV, resulting in increased VO(2)max, can only be observed after the onset of puberty

    Produção de Biomassa e composição química de pastagens consorciadas de Brachiaria brizantha cv. Marandu com o Stylozanthes guianiensis cv. Bela sob manejo orgânico e convencional em Planaltina-DF.

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    Objetivou-se neste estudo identificar a produção de matéria seca (MS) e os teores de proteína bruta (PB) de pastagens de Brachiaria brizantha cv. Marandu em consórcio com Stylosanthes Guianensis cv. Bela sob manejo orgânico e convencional. Para a correção do solo e adubação verde foi utilizado o calcário dolomítico, gesso agrícola e plantio da crotalária respectivamente para o manejo orgânico e convencional. No manejo convencional foi feita adubação nitrogenada, fosfatada e potássica com uréia, supertriplo e cloreto de potássio, respectivamente. No manejo orgânico, utilizou-se o termofosfato magnesiano e o termopotássio como fontes de fósforo e potássio, respectivamente. O delineamento experimental foi em Blocos Casualizados (DBC), com dois fatores e seis repetições, sendo feitos dois experimentos um em cada período (secas e águas). Para o consórcio, a produção de MS (kg.ha-1) no manejo convencional (3654,1; 9723,1 kg.ha-1) diferiu do orgânico (1596,7; 6214,5 kg.ha-1) no período das secas e das águas, respectivamente. No período seco os valores de PB foram superiores para o manejo orgânico (8,4%) em relação ao convencional (6,4%). A qualidade nutricional da pastagem consorciada sob manejo orgânico foi superior ao manejo convencional, no período seco e semelhante no período das águas, embora o manejo convencional apresentasse maior produtividade em ambos os períodos.ZOOTEC 2013

    Comparação dos sistemas de manejo de produção orgânico e convencional de pastagens de Brachiaria brizantha cv. Marandu em consorcio com o Stylosanthes guianensis cv. Bela em Planaltina - DF.

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    O objetivo deste trabalho foi comparar a produção e teor de matéria seca (MS) e proteína bruta (PB) de pastagens de Brachiaria brizantha cv. Marandu em consórcio com Stylosanthes Guianensis cv. Bela sob os sistemas de manejo orgânico e convencional. Para a correção do solo e adubação verde foi utilizado o calcário, gesso e plantio da crotalária respectivamente para o manejo orgânico e convencional. No manejo convencional foi feita adubação nitrogenada, fosfatada e potássica com uréia, supertriplo e cloreto de potássio, respectivamente. No manejo orgânico, utilizou-se o termofosfato magnesiano e o termopotássio, respectivamente. O delineamento experimental foi em blocos ao acaso, com 1 fator com três tratamentos: manejo orgânico, convencional e testemunha com três repetições com quatro amostras por parcela. Não houve diferenças estatísticas entre os sistemas de manejo para % MS e % PB da brachiaria, estilosantes e do consorcio entre ambos. Entretanto, foram observadas diferenças na produção de MS (kg ha) e PB (kg ha) entre os sistemas. Para a produção de MS (kg ha) e PB (kg ha) o manejo convencional (2815,6; 170,1 kg ha) não diferiu do orgânico (1610,8; 111,3 kg ha) e foi superior a testemunha (1158,5; 81,5 kg ha) respectivamente. O sistema de produção orgânico apresentou resultados satisfatórios de produção MS (kg ha) e PB (kg ha) nas condições experimentais da região de Planaltina-DF

    Analysis of the pathogenic potential of nosocomial Pseudomonas putida strains

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    Pseudomonas putida strains are ubiquitous in soil and water but have also been reported as opportunistic human pathogens capable of causing nosocomial infections. In this study we describe the multilocus sequence typing of four P. putida strains (HB13667, HB8234, HB4184 and HB3267) isolated from in-patients at the Besançon Hospital (France). The four isolates (in particular HB3267) were resistant to a number of antibiotics. The pathogenicity and virulence potential of the strains was tested ex vivo and in vivo using different biological models: human tissue culture, mammalian tissues and insect larvae. Our results showed a significant variability in the ability of the four strains to damage the host; HB13667 did not exhibit any pathogenic traits, HB4184 caused damage only ex vivo in human tissue cultures, and HB8234 had a deleterious effect in tissue culture and in vivo on rat skin, but not in insect larvae. Interestingly, strain HB3267 caused damage in all the model systems studied. The putative evolution of these strains in medical environments is discussed

    Understanding the conformational changes and molecular structure of furoyl thioureas upon substitution

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    1-Acyl thioureas [R1C(O)NHC(S)NR2R3] are shown to display conformational flexibility depending on the degree of substitution at the nitrogen atom. The conformational landscape and structural features for two closely related thioureas having R1 = 2-furoyl have been studied. The un-substituted 2-furoyl thiourea (I) and its dimethyl analogue, i.e. 1-(2-furoyl)-3,3-dimethyl thiourea (II), have been synthesized and fully characterized by spectroscopic (FT-IR, 1H and 13C NMR) and elemental analysis. According to single crystal X-ray diffraction analysis, compounds I and II crystallize in the monoclinic space group P21/c. In the compound I, the trans–cis geometry of the almost planar thiourea unit is stabilized by intramolecular Nsingle bondH ⋯ Odouble bondC hydrogen bond between the H atom of the cis thioamide and the carbonyl O atom. In compound II, however, the acyl thiourea group is non-planar, in good agreement with the potential energy curve computed at the B3LYP/6-31 + G(d,p) level of approximation. Centrosymmetric dimers generated by intermolecular N — H ⋯ O = C hydrogen bond forming R22(8) motif are present in the crystals. Intermolecular interactions have been rationalized in terms of topological partitions of the electron distributions and Hirshfeld surface analysis, which showed the occurrence of S ⋯ H, O ⋯ H and H ⋯ H contacts that display an important role to crystal packing stabilization of both thiourea derivatives.Instituto de Física La PlataCentro de Química Inorgánic

    Pyramidal core-shell quantum dot under applied electric and magnetic fields

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    We have theoretically investigated the electronic states in a core/shell pyramidal quantum dot with GaAs core embedded in AlGaAs matrix. This system has a quite similar recent experimental realization through a cone/shell structure [Phys. Status Solidi-RRL 13, 1800245 (2018)]. The research has been performed within the efective mass approximation taking into account position-dependent efective masses and the presence of external electric and magnetic felds. For the numerical solution of the resulting three-dimensional partial diferential equation we have used a fnite element method. A detailed study of the conduction band states wave functions and their associated energy levels is presented, with the analysis of the efect of the geometry and the external probes. The calculation of the non-permanent electric polarization via the of-diagonal intraband dipole moment matrix elements allows to consider the related optical response by evaluating the coefcients of light absorption and relative refractive index changes, under diferent applied magnetic feld confgurations

    Analysis of the pathogenic potential of nosocomial Pseudomonas putida strains

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    The Supplementary Material for this article can be found online at: http://journal.frontiersin.org/article/10.3389/fmicb.2015.00871Pseudomonas putida strains are ubiquitous in soil and water but have also been reported as opportunistic human pathogens capable of causing nosocomial infections. In this study we describe the multilocus sequence typing of four P. putida strains (HB13667, HB8234, HB4184, and HB3267) isolated from in-patients at the Besançon Hospital (France). The four isolates (in particular HB3267) were resistant to a number of antibiotics. The pathogenicity and virulence potential of the strains was tested ex vivo and in vivo using different biological models: human tissue culture, mammalian tissues, and insect larvae. Our results showed a significant variability in the ability of the four strains to damage the host; HB13667 did not exhibit any pathogenic traits, HB4184 caused damage only ex vivo in human tissue cultures, and HB8234 had a deleterious effect in tissue culture and in vivo on rat skin, but not in insect larvae. Interestingly, strain HB3267 caused damage in all the model systems studied. The putative evolution of these strains in medical environments is discussed.Work in this study was supported by the ERANET Pathogenomics Program through the ADHERS-Signature Project (reference: BIO2008-04419-E)Peer reviewe

    Exciton properties in zincblende InGaN-GaN quantum wells under the effects of intense laser fields

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    ABSTRACT: In this work, we study the exciton states in a zincblende InGaN/GaN quantum well using a variational technique. The system is considered under the action of intense laser fields with the incorporation of a direct current electric field as an additional external probe. The effects of these external influences as well as of the changes in the geometry of the heterostructure on the exciton binding energy are discussed in detail
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