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Search Results: 1 - 10 of 19902 matches for " RICARDO; POZO "
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Node Vulnerability under Finite Perturbations in Complex Networks
Ricardo Gutiérrez,Francisco del-Pozo,Stefano Boccaletti
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0020236
Abstract: A measure to quantify vulnerability under perturbations (attacks, failures, large fluctuations) in ensembles (networks) of coupled dynamical systems is proposed. Rather than addressing the issue of how the network properties change upon removal of elements of the graph (the strategy followed by most of the existing methods for studying the vulnerability of a network based on its topology), here a dynamical definition of vulnerability is introduced, referring to the robustness of a collective dynamical state to perturbing events occurring over a fixed topology. In particular, we study how the collective (synchronized) dynamics of a network of chaotic units is disrupted under the action of a finite size perturbation on one of its nodes. Illustrative examples are provided for three systems of identical chaotic oscillators coupled according to three distinct well-known network topologies. A quantitative comparison between the obtained vulnerability rankings and the classical connectivity/centrality rankings is made that yields conclusive results. Possible applications of the proposed strategy and conclusions are also discussed.
PLAGUICIDAS ORGANOCLORADOS PERSISTENTES EN SEDIMENTOS DE TRES LAGOS COSTEROS Y UN LAGO ANDINO DE CHILE CENTRAL
RICARDO BARRAL,KARLA POZO,URRUTIA ROBERTO,MARCO CISTERNAS
Boletín de la Sociedad Chilena de Química , 2001,
Abstract: Se evaluó la presencia y distribución de los compuestos orgánicos persistentes (COPs) en núcleos de sedimentos de los lagos Chica y Grande de San Pedro, Lleu-Lleu e Icalma. Los compuestos fueron extraídos mediante sistema soxhlet con solvente n-hexano, la identificación y cuantificación, de estos, se realizó por cromatografía gaseosa con detector de captura de electrones de 63Ni. Se realizó un análisis estadístico de componentes principales (ACP) y Correlación de Pearson. Los plaguicidas identificados en los sedimentos fueron: a-HCH, g-HCH, Heptacloro, Aldrin, Endrin, pp′-DDT, pp'-DDE y pp'-DDD. Los resultados indican variaciones en la distribución y concentración de los COPs, al comparar los lagos urbanos con los lagos prístinos. Destaca la presencia de pp'-DDE (rango: b.n.d- 1.68 ng g-1 peso seco) y pp'-DDT (rango: b.n.d- 0.89 ng g-1 peso seco) en tres de los cuatro cuerpos de agua analizados. El análisis estadístico identificó correlaciones significativas entre el pp'-DDE y pp'-DDD. No se detectaron correlaciones entre el pp'-DDT y sus metabolitos. El ACP permitió agrupar algunos compuestos orgánicos en función de sus concentraciones y degradación a través del tiempo. Se concluye que Laguna Chica de San Pedro presentó las concentraciones más altas de COPs, las cuales son bajas al ser comparadas con concentraciones detectadas en áreas limpias del Sur de Chile We have measured concentrations and distribution of Persistent Organic Compounds (POC) in sediment cores from four Chilean lakes: Laguna Chica de San Pedro, Laguna Grande de San Pedro, Lleu-lleu, and Icalma. The organochlorine compounds were extracted with n-hexane in a soxhlet system and then identified and quantified by gas chromatography using a 63 Ni Electron Capture Detector. Statistical analyses were performed using a Principal Components Analysis (PCA) and the Pearson Correlation. The following pesticides were identified in the sediments: a-HCH, Lindane, Heptachlor, Aldrin, pp'-DDT, pp'-DDE, and pp'-DDD. The results show variation in both POC distribution and concentration when comparing pristine and urban lakes. It is important to note that pp'-DDE (range:b.d.l.-1.68 ng g-1 d.w.) and pp'-DDT (range: b.d.l.-0.89 ng g-1 d.w.) were present in three of the four lakes in the study. The statistical analyses showed significant correlations between pp'-DDE and pp'-DDD. Correlations between pp'-DDT and its metabolites were not detected. The PCA showed groupings of some of the organic compounds based on concentration and degradation over time. It is concluded that Laguna Chica de San Pedro is the l
Adaptability and Genotype x Environment Interaction of Spring Wheat Cultivars in Chile using Regression Analysis, AMMI, and SRAG Adaptabilidad e Interacción Genotipo x Ambiente en Trigos de Primavera utilizando Análisis de Regresión, AMMI y SREG
Dalma Castillo,Iván Matus,Alejandro del Pozo,Ricardo Madariaga
Chilean Journal of Agricultural Research , 2012,
Abstract: Wheat (Triticum aestivum L.) genetic improvement objectives include obtaining cultivars capable of expressing their maximum potential yield and quality in diverse environments. This make necessary to know and define the environment in which a variety can express its maximum potential yield and quality. The objective of this study was to assess which method is the most efficient to study cultivars response in multiple environments. For this, we analyze the adaptability, stability, and genotype x environment (GxE) interaction effect, grain yield, sedimentation, and wet gluten content of 13 spring wheat cultivars sown in six environments in the central-south and southern zones of Chile during two seasons. The data were analyzed by regression analysis, additive main effects and multiplicative interaction (AMMI), and the sites regression (SREG) model. By this was thus established that SREG analysis is the most efficient for this type of study since, in addition to analyzing stability, adaptability, and effect (GxE), it allows identifying the best cultivar. In this case, 'Pandora-INIA' stands out by exhibiting the best yield (7.38 t ha-1), high sedimentation (36.95 cm3), and wet gluten (41.54%) indices in all the environments, and this positions it as a variety having both high yield and quality. Dentro de los objetivos del mejoramiento genético del trigo (Triticum aestivum L.) figura la obtención de variedades capaces de expresar su máximo potencial de rendimiento y calidad en diversos ambientes. Por lo cual es necesario conocer y definir el ambiente en que una variedad puede expresar al máximo su potencial de rendimiento y de calidad. El objetivo de este trabajo fue determinar una metodología eficiente para analizar la respuesta de diversos cultivares de trigo a distintos ambientes. Para ello se analizó la adaptabilidad, estabilidad y la interacción Genotipo x Ambiente (GxE) de 13 variedades de trigo de primavera, sembradas, en seis ambientes de la zona centro sur y sur de Chile, durante dos temporadas, evaluando rendimiento de grano, sedimentación y contenido de gluten húmedo. Los resultados fueron sometidos a análisis de regresión, análisis de efectos principales aditivos e interacción multiplicativa (AMMI) y modelo de regresión de sitios (SREG), estableciendo que el análisis SREG es el más eficiente para este tipo de estudio, ya que además de analizar estabilidad, adaptabilidad y efecto (GxE), permite identificar cuál es la mejor variedad. 'Pandora-INIA' presentó el mejor rendimiento (7,38 t ha-1), altos índices de sedimentación (36,95 cm3) y gluten húme
HERMES: towards an integrated toolbox to characterize functional and effective brain connectivity
Guiomar Niso,Ricardo Bru?a,Ernesto Pereda,Ricardo Gutiérrez,Ricardo Bajo,Fernando Maestú,Francisco del-Pozo
Computer Science , 2013, DOI: 10.1007/s12021-013-9186-1
Abstract: The analysis of the interdependence between time series has become an important field of research in the last years, mainly as a result of advances in the characterization of dynamical systems from the signals they produce, the introduction of concepts such as generalized and phase synchronization and the application of information theory to time series analysis. In neurophysiology, different analytical tools stemming from these concepts have added to the 'traditional' set of linear methods, which includes the cross-correlation and the coherency function in the time and frequency domain, respectively, or more elaborated tools such as Granger Causality. This increase in the number of approaches to tackle the existence of functional (FC) or effective connectivity (EC) between two (or among many) neural networks, along with the mathematical complexity of the corresponding time series analysis tools, makes it desirable to arrange them into a unified-easy-to-use software package. The goal is to allow neuroscientists, neurophysiologists and researchers from related fields to easily access and make use of these analysis methods from a single integrated toolbox. Here we present HERMES (http://hermes.ctb.upm.es), a toolbox for the Matlab environment (The Mathworks, Inc), which is designed for the analysis functional and effective brain connectivity from neurophysiological data such as multivariate EEG and/or MEG records. It includes also visualization tools and statistical methods to address the problem of multiple comparisons. We believe that this toolbox will be very helpful to all the researchers working in the emerging field of brain connectivity analysis.
PLAGUICIDAS ORGANOCLORADOS PERSISTENTES EN SEDIMENTOS DE TRES LAGOS COSTEROS Y UN LAGO ANDINO DE CHILE CENTRAL
BARRAL,RICARDO; POZO,KARLA; ROBERTO,URRUTIA; CISTERNAS,MARCO; PACHECO,PATRICIA; FOCARDI,S.;
Boletín de la Sociedad Chilena de Química , 2001, DOI: 10.4067/S0366-16442001000200008
Abstract: we have measured concentrations and distribution of persistent organic compounds (poc) in sediment cores from four chilean lakes: laguna chica de san pedro, laguna grande de san pedro, lleu-lleu, and icalma. the organochlorine compounds were extracted with n-hexane in a soxhlet system and then identified and quantified by gas chromatography using a 63 ni electron capture detector. statistical analyses were performed using a principal components analysis (pca) and the pearson correlation. the following pesticides were identified in the sediments: a-hch, lindane, heptachlor, aldrin, pp'-ddt, pp'-dde, and pp'-ddd. the results show variation in both poc distribution and concentration when comparing pristine and urban lakes. it is important to note that pp'-dde (range:b.d.l.-1.68 ng g-1 d.w.) and pp'-ddt (range: b.d.l.-0.89 ng g-1 d.w.) were present in three of the four lakes in the study. the statistical analyses showed significant correlations between pp'-dde and pp'-ddd. correlations between pp'-ddt and its metabolites were not detected. the pca showed groupings of some of the organic compounds based on concentration and degradation over time. it is concluded that laguna chica de san pedro is the lake with the highest concentration of poc's, although the levels appear low when compared with those measured in pristine areas in southern chile
La economía global de la imagen
Pozo,Patricio;
ARQ (Santiago) , 2001, DOI: 10.4067/S0717-69962001004900018
Abstract: patricio pozo dissects a group of new scenarios that constitute and configure the new territory of images, superimposed to reality. figures of the everyday are translated until the exhaustion into two-dimension surface trying to represent, to support and to transmit a transactional world. a new race of designers -no longer anonymous artisans but visual authors of texts and interpreters of contents- will be in charge of managing and organizing this new scene
La economía global de la imagen
Patricio Pozo
ARQ , 2001,
Abstract: Un conjunto de nuevos escenarios que constituyen y configuran el nuevo territorio, superpuesto a la realidad, de las imágenes. Figuras cotidianas traducidas hasta el cansancio en dos dimensiones buscando representar y transmitir una globalidad transable. Una nueva raza de dise adores, ya no artesanos anónimos sino autores visuales de textos e intérpretes de contenidos, será la encargada de manejar y diagramar esta nueva escena Patricio Pozo dissects a group of new scenarios that constitute and configure the new territory of images, superimposed to reality. Figures of the everyday are translated until the exhaustion into two-dimension surface trying to represent, to support and to transmit a transactional world. A new race of designers -no longer anonymous artisans but visual authors of texts and interpreters of contents- will be in charge of managing and organizing this new scene
Conselho editorial, estatiística e nominata
Hamilton Pozo
Revista da Micro e Pequena Empresa , 2011,
Abstract:
Editorial
Hamilton Pozo
Revista da Micro e Pequena Empresa , 2011,
Abstract:
Editorial
Hamilton Pozo
Revista da Micro e Pequena Empresa , 2011,
Abstract:
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