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Search Results: 1 - 10 of 25628 matches for " Alberto Romero Gracia "
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Fitting Nonlinear Calibration Curves: No Models Perfect  [PDF]
Julia Martin, Alberto Romero Gracia, Agustín G. Asuero
Journal of Analytical Sciences, Methods and Instrumentation (JASMI) , 2017, DOI: 10.4236/jasmi.2017.71001
Abstract: The study of the calibration of a series of compounds of environmental concern (six perfluoroalkyl compounds (perfluorooctane sulfonic acid and five perfluoroalkyl carboxylic acids), three preservatives (methyl-, ethyl- and propylparabens) and the brominated flame retardant hexabromocyclododecane) by LC-MS/MS has been carries out, with a view to their simultaneous determination in samples of environmental interest. In some cases nonlinear calibration curves are obtained, but restricting the concentration range a linear model may be used to fit the data. Residual analysis has been performed in order to verify which models fit the data better, opting for a compromise decision given the apparent complexity of residuals plots. As Box states there are no perfect models (but models that work better than others).
Two Frequenins in Drosophila: unveiling the evolutionary history of an unusual Neuronal Calcium Sensor (NCS) duplication
Alejandro Sánchez-Gracia, Jesús Romero-Pozuelo, Alberto Ferrús
BMC Evolutionary Biology , 2010, DOI: 10.1186/1471-2148-10-54
Abstract: Surprisingly, we have found no amino acid replacements fixed across the twelve Drosophila species surveyed. In contrast, synonymous substitutions have been prevalent in the evolution of the coding region of frq1 and frq2, indicating the presence of strong functional constraints following gene duplication. Despite that, we have detected that significant evolutionary rate acceleration had occurred in Frq1 in early times from the duplication, in which positive selection (likely promoting functional diversification) had probably an important role. The analysis of sequence conservation and DNA topology at the non-coding regions of both genes has allowed the identification of DNA regions candidates to be cis-regulatory elements. The results reveal a possible mechanism of regulatory diversification between frq1 and frq2.The presence of two Frequenins in Drosophila and the rapid accumulation of amino acid substitutions after gene duplication are very unusual features in the evolution of the Frq/NCS-1 subfamily. Here we show that the action of positive selection in concordance with some extent of regulatory diversification might explain these findings. Selected amino acid substitutions in Frq1 likely contributed to the functional divergence between the two duplicates, which, in turn, should have diverged in their regulation by Ecdysone-induced early genes.Many different aspects of neuronal function, including neurotransmitter release from synaptic vesicles, are regulated by alterations in the concentration of intracellular free Ca2+ [1,2]. The transduction of calcium signals into appropriate physiological responses is frequently mediated by a range of calcium sensor proteins, which act as effectors and modulators in signalling pathways [3]. The specific effects of these changes depend on their affinity for Ca2+, their cellular localization in relation to the Ca2+ entry signal and their interaction with other proteins. A number of calcium binding proteins related to the ubiqu
Las redes de información y su importancia para la investigación científica.
Alberto Romero
Revista Venezolana de Gerencia , 2002,
Abstract: La información es la materia prima del conocimiento, el cual se ha ido convirtiendo cada vez mas en la principal fuente de poder y de riqueza de las naciones. En este sentido, la organización de redes de información, como apoyo a la investigación, es una necesidad inaplazable. El propósito de este trabajo es analizar las características de las diferentes herramientas utilizadas para el funcionamiento de las comunidades en red, tales como las listas de discusión a través del correo electrónico, los boletines, los newsletters, los chats y los foros virtuales. Los resultados revelan que: 1) Las tecnologías de información y comunicación son una importante vía de apropiación social del conocimiento del cual pueden beneficiarse los países que han llegado tardíamente al proceso, realizando esfuerzos de inversión física y de formación de recursos humanos. 2) Las redes de información (mundiales, regionales y nacionales) juegan un importante papel en la consolidación de comunidades científicas en el mundo. Las listas de discusión, boletines, novedades, salas de conversación y foros virtuales son una herramienta importante de las comunidades científicas para el intercambio de información y experiencias. Se concluye sobre la necesidad de desarrollar redes para fortalecer las comunidades científicas.
Construcción lingüística y discursiva de Bolívar y Zamora en los mensajes presidenciales Venezolanos
León,Florelba; Gracia Romero,María;
Opción , 2008,
Abstract: this paper analyzes the linguistic and discursive construction of the historical figures simón bolívar and ezequiel zamora in the political speech of the current venezuelan president. by studying speech using a semantic-pragmatic approach, the investigation is based on the conjunction of the theoretical and methodologic contributions of linguistic semantics (pottier, 1992, 1993); the textual linguistics of van dijk (1980, 1990, 1994, 1999) and it connects with the ideas that have been being adapted and developed in the research line from applied linguistics to discourse analysis (molero, 1985, 2002, 2003). the corpus includes a total of seventeen (17) presidential speeches emitted by the leader from the year 2001 to 2006. analysis of the corpus permitted obtaining the following results: a) the construction of ?i-we? is demonstrated at the logical-conceptual level through use of causatives, which indicate processes of degradation caused by opponents and processes of improvement that the ?i? (discursive subject) carries out; b) actancial analysis reveals the identification that the leader establishes between the ?i? and the historical figures of bolívar and zamora; c) semantic fields demonstrate that the discursive meaning depends on the contextual variables as well as the lexical strategies that allow for re-contextualizing meanings from other social and discursive practices legitimized and widely known by the receivers. conclusions are that the use of these historical figures contributes to persuading the public about the legitimacy of the policies developed from the government.
Las Tecnologías de información y comunicación en el gobierno electrónico de la alcaldía de Maracaibo
Rincon Mena,Derlisiret; Romero Paredes,Maria Gracia;
Opción , 2003,
Abstract: the main purpose of this work is to explore the incidence and use of information technologies in municipal public electronic management in the maracaibo municipality mayors office. the hypothesis was that the use of information and communication technologies (tic′s) generates organizational changes and causes modifications both for operators and users of the system. the target population was divided into three groups: directors of the mayors office; workers in the tic system in this institution, and users of the information center (infocentro) located at the lia bermudez art center in maracaibo (cam-lb) . the results of this research indicate that theweb does not represent an effective alternative of municipal public management, because among other factors, there is a technological gap between those who have access to the technology and those who do not. for this reason, the citizens make very little use of this service, and knowledge of its existence is little known in the population.
Construcción lingüística y discursiva de Bolívar y Zamora en los mensajes presidenciales venezolanos
Florelba León,María Gracia Romero
Opción , 2008,
Abstract: En este artículo se analiza la construcción lingüística y discursiva de las figuras históricas de Simón Bolívar y Ezequiel Zamora en el discurso político del actual presidente venezolano. Mediante un estudio del discurso bajo un enfoque semántico-pragmático, la investigación se fundamenta en la conjunción de los aportes teóricos y metodológicos de la Semántica Lingüística (Pottier, 1992, 1993); de la lingüística textual de Van Dijk (1980, 1990, 1994, 1999) y se articula en los esquemas que se han venido adaptando y desarrollando en la línea de investigación de Lingüística aplicada al análisis del discurso (Molero, 1985, 2002, 2003). El corpus comprende un total de 17 alocuciones presidenciales emitidas por el líder desde el a o 2001 hasta el 2006. El análisis del corpus permitió obtener los siguientes resultados: a) la construcción del "yo-nosotros" se evidencia en el nivel lógico-conceptual mediante la utilización de los causativos, los cuales se alan los procesos de degradación causados por los oponentes y los procesos de mejoramiento que lleva a cabo el "Yo" (sujeto discursivo); b) el análisis actancial revela la identificación que establece el líder entre el "Yo" y las figuras históricas de Bolívar y Zamora; c) los campos semánticos demuestran que el sentido discursivo depende tanto de las variables contextuales como de las estrategias lexicales, que permiten recontextualizar sentidos de otras prácticas sociales y discursivas legitimadas y ampliamente conocidas por los receptores. Se concluye que la utilización de estas figuras históricas contribuye a persuadir al público acerca de la legitimidad de las políticas que se desarrollan desde el Gobierno.
La Guerra Civil Espa?ola y la polarización ideológica y política: la Argentina 1936-1946
ROMERO,LUIS ALBERTO;
Anuario Colombiano de Historia Social y de la Cultura , 2011,
Abstract: deeply moved by the spanish civil war, the spanish community in argentina, and society as a whole, mobilized in support of one side or the other. the majority, which belonged to a liberal, democratic, and reformist tradition, adhered to the republic, but the supporters of the franco regime, recruited mainly from a dynamic catholic and nationalist anti-liberalism, constituted a significant minority. this article analyzes the repercussions of that polarization in politics, as well as its translation and adaptation to local circumstances, with special emphasis on the alternatives of the anti-fascist front. the latter played an important role in the cultural and intellectual field, in which emigrated spanish republicans had a strong presence. there were two turning points in the process: the military coup of june 1943, which was interpreted as the triumph of fascism in argentina, and the election, in 1946, of perón, who recruited the support of labor unions that had until then supported anti-fascism. explaining this paradoxical result is the objective of this article.
La Argentina entre sus centenarios
Romero,Luis Alberto;
Revista Pilquen , 2010,
Abstract: in this text we examine the image of argentina in its first centenary, in 1910, and the present vision, at its second centenary. we focus in three main issues: the republic, the nation and the state. we contrast the optimism of 1910 with the present pessimism, and lack of great expectations. we analyze what happened between 1910 and 2010, especially the great change happened in the mid seventies.
Religión y mitología de los uitotos
Robayo Romero Camilo Alberto
Forma y Función , 1995,
Abstract: Recopilación y análisis de textos y etnografía uitoto hecha por el gran arqueólogo y etnógrafo prusiano, editada originalmente, en alemán (1921-1923), esta primera edición castellana se debe a una de las investigaciones del Departamento de Lingüística de la Universidad Nacional.
SOL SERRANO, Qué hacer con Dios en la República? Política y secularización en Chile (1845-1885)
Luis Alberto Romero
Historia (Santiago) , 2009,
Abstract:
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