8,629 research outputs found

    WebDocBall : a graphical visualisation tool for web search results

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    In the Web search process people often think that the hardest work is done by the search engines or by the directories which are entrusted with finding the Web pages. While this is partially true, a not less important part of the work is done by the user, who has to decide which page is relevant from the huge set of retrieved pages. In this paper we present a graphical visualisation tool aimed at helping users to determine the relevance of a Web page with respect to its structure. Such tool can help the user in the often tedious task of deciding which page is relevant enough to deserve a visit

    Quantitative Analysis of the Effective Functional Structure in Yeast Glycolysis

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    Yeast glycolysis is considered the prototype of dissipative biochemical oscillators. In cellular conditions, under sinusoidal source of glucose, the activity of glycolytic enzymes can display either periodic, quasiperiodic or chaotic behavior. In order to quantify the functional connectivity for the glycolytic enzymes in dissipative conditions we have analyzed different catalytic patterns using the non-linear statistical tool of Transfer Entropy. The data were obtained by means of a yeast glycolytic model formed by three delay differential equations where the enzymatic speed functions of the irreversible stages have been explicitly considered. These enzymatic activity functions were previously modeled and tested experimentally by other different groups. In agreement with experimental conditions, the studied time series corresponded to a quasi-periodic route to chaos. The results of the analysis are three-fold: first, in addition to the classical topological structure characterized by the specific location of enzymes, substrates, products and feedback regulatory metabolites, an effective functional structure emerges in the modeled glycolytic system, which is dynamical and characterized by notable variations of the functional interactions. Second, the dynamical structure exhibits a metabolic invariant which constrains the functional attributes of the enzymes. Finally, in accordance with the classical biochemical studies, our numerical analysis reveals in a quantitative manner that the enzyme phosphofructokinase is the key-core of the metabolic system, behaving for all conditions as the main source of the effective causal flows in yeast glycolysis.Comment: Biologically improve

    Seed beetles (Coleoptera: Bruchidae) associated with Acacia cornigera (L.) Willd., with description of a new species of Acanthoscelides Schilsky

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    Presented herein is a key to identify species of Bruchidae associated with Acacia cornigera (L.). For each species, host records, distributions and bionomics are given. A new species of Acanthoscelides Schilsky is described and figured; Acanthoscelides sauli Romero, Cruz, and Kingsolver

    Clinkering and hydration study of non-active and active Belite-Alite-Ye'elimite (BAY) cements

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    The aim of AIM is to promote industry-driven, interdisciplinary research in material science and engineering in order to provide leading-edge, sustainable solutions to the challenges facing engineers in today’s changing society and environment. http://www.ucl.ac.uk/aim/conference-info/37ccsThe manufacturing process of ye'elimite rich cements emit about 15-37% less CO2 to the atmosphere than OPC. Cements that contain belite, ye’elimite and ferrite, known as BYF cements, are promising eco-friendly binders. However, belite, their main phase, shows a slow hydrating behaviour; therefore the corresponding mortars present lower mechanical strengths than OPC at early ages. To solve this problem, BYF clinkers can be activated by: i) forming alite jointly with belite and ye’elimite during clinkering, known as BAY clinkers. The alite and ye’elimite reaction with water should develop high mechanical strengths at early ages, besides, belite contributes to later curing times. ii) A second activation is based on the stabilisation of alpha forms of belite by dopants. The objective of this work is to obtain two types of BAY clinkers (standard and active BAY) using CaF2 as mineraliser and borax as dopant agent to stabilize alpha forms of belite phase. After that, anhydrite was added as sulphate source to obtain the corresponding cements. The hydration behaviour of these cements has been studied through rheological and x-ray diffraction measurements, the latter combined with Rietveld quantitative phase analysis. In addition, mechanical and dimensional properties of BAY mortars are also presented and discussed.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    A profile of ICT Entrepreneurs in Brazil

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    This paper presents the first results on Brazil of an international survey on how entrepreneurs from BRIC countries perceive their environment. The first section describes briefly the present context of Brazilian ICT entrepreneurs. The second question describes the methodology of the research and the third section describes the main results. The fourth section presents a discussion of results, and the fifth section the conclusions

    Timing the formation and assembly of early-type galaxies via spatially resolved stellar populations analysis

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    To investigate star formation and assembly processes of massive galaxies, we present here a spatially-resolved stellar populations analysis of a sample of 45 elliptical galaxies (Es) selected from the CALIFA survey. We find rather flat age and [Mg/Fe] radial gradients, weakly dependent on the effective velocity dispersion of the galaxy within half-light radius. However, our analysis shows that metallicity gradients become steeper with increasing galaxy velocity dispersion. In addition, we have homogeneously compared the stellar populations gradients of our sample of Es to a sample of nearby relic galaxies, i.e., local remnants of the high-z population of red nuggets. This comparison indicates that, first, the cores of present-day massive galaxies were likely formed in gas-rich, rapid star formation events at high redshift (z>2). This led to radial metallicity variations steeper than observed in the local Universe, and positive [Mg/Fe] gradients. Second, our analysis also suggests that a later sequence of minor dry mergers, populating the outskirts of early-type galaxies (ETGs), flattened the pristine [Mg/Fe] and metallicity gradients. Finally, we find a tight age-[Mg/Fe] relation, supporting that the duration of the star formation is the main driver of the [Mg/Fe] enhancement in massive ETGs. However, the star formation time-scale alone is not able to fully explain our [Mg/Fe] measurements. Interestingly, our results match the expected effect that a variable stellar initial mass function would have on the [Mg/Fe] ratio.Comment: Accepted for publication in MNRA

    Tabla de quentas, con las cinco reglas llanas, y de quebrados con sus diferencias, reglas de tres ...

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    Copia digital. Valladolid : Junta de Castilla y León. Consejería de Cultura y Turismo, 2009-2010Datos de la publicación tomados del colofónSign.: A-D

    HySEA model verification for Tohoku 2011 Tsunami. Application for mitigation tsunami assessment

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    In many aspects Tohoku-Oki 2011 mega tsunami has changed our perception of tsunami risk. The tsunami-HySEA model is used to numerically simulate this event and observed data will we used to verify the model results. Three nested meshes of enhanced resolution (4 arc-min, 32 arc-sec and 2 arc-sec) will be used by the numerical model. The propagation mesh covers all Pacific Ocean with more of 7 million cells. An intermediate mesh with 5 millions cells contains the Japanese archipelago and, finally, two finer meshes, with nearly 8 and 6 millions cells, cover Iwate and Miyagi Prefectures at Tohoku region, the most devastated areas hit by the tsunami. The presentation will focus on the impact of the tsunami wave in these two areas and comparisons with observed data will be performed. DART buoys time series, inundation area and observed runup is used to assess model performance. The arrival time of the leading flooding wave at the vicinity of the Senday airport, as recorded by video cameras, is also used as verification data for the model. After this tsunami, control forests as well as breakwaters has been discussed as suitable mitigation infrastructures. As particular case, we will analyse the evolution of the tsunami in the area around the Sendai airport (Miyagi Prefecture) and its impact on the airport. A second simulation has been performed, assuming the existence of a coastal barrier protecting the area. The role of this barrier in modifying tsunami wave evolution and mitigating flooding effects on the airport area are discussed. The protection effect of the breakwaters near Kamaishi (Iwate Prefecture) is also assessed. The numerical model shows how these structures, although did not provide a full protection to tsunami waves, they helped to largely mitigate its effects in the area.Acknowledgements. This research has been partially supported by the Junta de Andalucía research project TESELA (P11-RNM7069), the Spanish Government Research project DAIFLUID (MTM2012-38383-C02-01) and Universidad de Málaga, Campus de Excelencia Internacional Andalucía Tech. The multi-GPU computations were performed at the Laboratory of Numerical Methods (University of Malaga)

    Diagnóstico estratégico de la Asociación de Horticultores del municipio de Sébaco del departamento de Matagalpa, periodo 2014

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    El tema sobre la cual se desarrolló esta investigación trata del diagnóstico estratégico de la empresa Asociación de Horticultores del municipio de Sébaco en el periodo 2014. En la cual se identificó la situación actual de la empresa, así como también las diferentes problemáticas existentes, de igual manera se determinó el funcionamiento de la organización y se describió el entorno empresarial en el que se desenvuelve tanto en la parte interna y externa de la Asociación. Esta investigación es aplicada del tipo cualitativo con algunos elementos cuantitativos. Esta investigación es realizada con el objetivo de elaborar un diagnóstico estratégico a la Asociación de Horticultores del Municipio de Sébaco en el periodo 2014. Puesto que esta empresa se dedica a la comercialización de cebolla a nivel nacional, e internacional y desconocen la importancia de la realización del análisis empresarial para mejorar su desarrollo. La importancia de este diagnóstico es conocer, la situación actual de la empresa, y a través de los resultados aplicar estrategias adecuadas para la elaboración de un plan estratégico que contribuya a una mejor participación en los diferentes mercados para obtener las metas propuestas y cumplir con los objetivos empresariales. ADHORTISEB, no elabora diagnóstico estratégico, lo que ha complicado el logro de sus metas que pretende alcanzar, las actividades de la empresa no son controladas de manera eficiente puesto que no cuentan con manuales de procedimientos establecidos, sino que lo hacen técnicamente como productores, y con ayudas de los ingenieros agrónomos de instituciones como el MAGFOR y el MIFIC. Esta Asociación cuentas con muchas herramientas las cuales pueden ser aprovechadas con los resultados obtenidos de este diagnóstico, el cual aporta estrategias para desarrollarse mejor en el mercado y tomar decisiones eficiente
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