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Search Results: 1 - 10 of 8982 matches for " Alejandro Herrada "
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MORTALIDAD NEONATAL EN EL HOSPITAL DE SULLANA. UN ESTUDIO CASO CONTROL.
Clever H. Leiva Herrada,Jenny L. Parra Alejandro
Electronic Journal of Biomedicine , 2008,
Abstract:
Scaling properties of protein family phylogenies
Alejandro Herrada, Víctor M Eguíluz, Emilio Hernández-García, Carlos M Duarte
BMC Evolutionary Biology , 2011, DOI: 10.1186/1471-2148-11-155
Abstract: The comparative analysis between protein and species phylogenies shows that both sets of phylogenies share a remarkably similar scaling behavior, suggesting the universality of branching rules and of the evolutionary processes that drive biological diversification from gene to species level. In order to explain such generality, we propose a simple model which allows us to estimate the proportion of evolvability/robustness needed to approximate the scaling behavior observed in the phylogenies, highlighting the relevance of the robustness of a biological system (species or protein) in the scaling properties of the phylogenetic trees.The invariance of the scaling properties at levels spanning from genes to species suggests that rules that govern the incapability of a biological system to diversify are equally relevant both at the gene and at the species level.During the last century, an important effort has been devoted to the understanding of diversification patterns and processes in terms of branching evolutionary trees [1-7]. Tempo and mode of genetic change, and their connections with tempo and mode of speciation is an important issue in this context. In that sense, we address the question of whether similar forces act across the gene level and species-level evolution [8-10], through a comparative analysis of the topological behavior of protein and species phylogenies.Previous analyses of the topological properties of phylogenies have revealed universal patterns of phylogenetic differentiation [3,6,7,11,12]. This means that the impact of evolutionary forces shaping the diversity of life on Earth on the shape of phylogenetic trees is, at least to the level of detail captured by the descriptors used, similar across a broad range of scales, from macro-evolution to speciation and population differentiation, and across diverse organisms such as eukaryotes, eubacteria, archaea or viruses, thereby. This together with the fact that evolutionary forces work at molecular lev
FACTORES ASOCIADOS A MORTALIDAD NEONATAL EN EL HOSPITAL DE SULLANA (PERU)
Clever Humberto Leiva Herrada,Omar Castro Atarama,Jenny Liz Parra Alejandro
Electronic Journal of Biomedicine , 2005,
Abstract: SUMMARYOBJECTIVE: To know the factors that is ssociated to neonatal mortality in the Hospital of Sullana between July and December of the 2003.METODO: A study observational-descriptive. The criterion of inclusion of the sample was constituted by all the newborn ones been born and died in the Hospital of Sullana, during July to December June of the 2003.RESULTS: Of the 36 newborn ones that passed away. There were 32 in the group of early neonatal mortality (MNP) and 4 in the group of late neonatal mortality (MNT). The rate of neonatal mortality for this period was 19.67 x 1000. 50% (18) of the mothers had not had one gestation previously. (77,78%) they had prenatal control. 80.56% of the newborn ones had cephalic presentation. 52.78% of the newborn ones had normal childbirth. 55.56% of the newborn ones were premature, 69.44% were adapted for the gestacional age, 41.67% presented/displayed depression (hypoxia) severe to the minute of life. The weight average of the newborn ones was of 2218,6 grams. The gestacional age in average was of 34,5 weeks. The maternal age in average was of 26,111 years.CONCLUSIONS: - The most frequent complication was the hypoxia. The prematurity when being associated to other problems was the most important cause of death. We must try the prenatal control universally.
Simple models for scaling in phylogenetic trees
Emilio Hernandez-Garcia,Murat Tugrul,E. Alejandro Herrada,Victor M. Eguiluz,Konstantin Klemm
Quantitative Biology , 2008, DOI: 10.1142/S0218127410026095
Abstract: Many processes and models --in biological, physical, social, and other contexts-- produce trees whose depth scales logarithmically with the number of leaves. Phylogenetic trees, describing the evolutionary relationships between biological species, are examples of trees for which such scaling is not observed. With this motivation, we analyze numerically two branching models leading to non-logarithmic scaling of the depth with the number of leaves. For Ford's alpha model, although a power-law scaling of the depth with tree size was established analytically, our numerical results illustrate that the asymptotic regime is approached only at very large tree sizes. We introduce here a new model, the activity model, showing analytically and numerically that it also displays a power-law scaling of the depth with tree size at a critical parameter value.
Pretty, but dangerous! Records of non-native Monk Parakeets (Myiopsitta monachus) in Mexico Bonita pero peligrosa! Registros de la cotorra argentina (Myiopsitta monachus) en México
Ian MacGregor-Fors,Rafael Calderón-Parra,Alejandro Meléndez-Herrada,Silvia López-López
Revista mexicana de biodiversidad , 2011,
Abstract: The Monk Parakeet (Myiopsitta monachus) is native to South America and has been introduced by the pet market to several countries around the world. In this note, we compiled records for this species in Mexico and report the first sight-recording of this species in the state of Michoacán and several nesting localities within the Metropolitan area of México City. Most records are of individuals escaped or released from captivity. Also, we review the negative effects that this species has had in invaded areas from around the world. Our analysis suggests the possible beginning of an invasion in Mexico that could have dramatic negative ecological and economic effects throughout this biodiverse country. La cotorra argentina (Myiopsitta monachus) es nativa de Sudamérica y ha sido introducida a través del comercio de mascotas en diversos países del mundo. En esta nota compilamos los registros de esta especie para México, además de reportarla por primera vez para el estado de Michoacán y diversas localidades de anidación en la zona metropolitana de la ciudad de México. La mayoría de los registros son de individuos que han escapado o han sido liberados intencionalmente del cautiverio. Además, discutimos los efectos que ha tenido esta especie en otros lugares del mundo. Los registros compilados en esta nota sugieren el inicio de un proceso masivo de invasión por parte de la cotorra argentina, el cual podría tener efectos económicos y ecológicos dramáticos en un país biodiverso como México.
Preparing future teachers against racism: A training experience at the University of Almería
Rosario Isabel Herrada Valverde
Revista Electronica Interuniversitaria de Formación del Profesorado , 2008,
Abstract: The arrival of a large number of immigrants at Spanish schools has turned classrooms into multicultural spaces. This is the reason why prospective teachers must receive appropriate training in cultural diversity. This paper presents a detailed study of the concept of racism as perceived by a group of prospective teachers who took the course on “Education and Socio-cultural Diversity”, and this concept’s influence to promote a change in their views and attitudes in topics associated with racism. The results show how students dealt with this concept and acknowledged some of their main prejudices. This research demands the inclusion of subjects related to cultural diversity in tertiary education, particularly at the initial stage of teacher-training studies.
El concepto de cultura entre los futuros maestros: un análisis etnográfico. [The concept of culture used by future teachers: an ethnographic analysis]
Herrada Valverde, Rosario Isabel
Revista Electrónica de Investigación y Evaluación Educativa , 2008,
Abstract: The arrival of immigrant families to Spain from other countries has led a sharp increase in foreign students in Spanish schools, which have in turn become multicultural spaces. . The concept of culture could become the framework on which are based discriminations, prejudices and stereotypes towards groups and individuals. This paper describes the main results of an ethnographic study about the perceived concept of culture of students at a Spanish university. In particular this study was developed from data collected among students who, during academic year 2003/2004, attended to “Education and Socio-cultural Diversity”, subject included in this academic year for the first time in the Degree in Education at the University of Almería. This research not only seeks to give an insight into the concept of culture handle these students, but also to analyze the influence of the subject on the concept of culture used by students as well as the influence of the lecturer on their views and attitudes. La llegada de familias inmigrantes a nuestro país ha conllevado un notable incremento de inmigrantes o hijos de inmigrantes en las escuelas, lo que las han convertido en espacios multiculturales. El concepto de cultura podría convertirse en el andamiaje sobre el que se estructuran discriminaciones, prejuicios y estereotipos hacia grupos e individuos. En este artículo se expone un estudio de corte etnográfico llevado a cabo en un aula universitaria, entre los estudiantes que cursaron Educación y Diversidad Sociocultural (EDSC) el curso académico 2003/2004. Esta investigación no sólo pretende dar una visión sobre qué concepto de cultura manejaban estos estudiantes, sino además mostrar la influencia de la asignatura sobre el concepto de cultura empleado por el alumnado, así como la influencia ejercida por el profesor universitario para hacer posible ese cambio conceptual y/o actitudinal.
Universal Scaling in the Branching of the Tree of Life
E. Alejandro Herrada, Claudio J. Tessone, Konstantin Klemm, Víctor M. Eguíluz, Emilio Hernández-García, Carlos M. Duarte
PLOS ONE , 2008, DOI: 10.1371/journal.pone.0002757
Abstract: Understanding the patterns and processes of diversification of life in the planet is a key challenge of science. The Tree of Life represents such diversification processes through the evolutionary relationships among the different taxa, and can be extended down to intra-specific relationships. Here we examine the topological properties of a large set of interspecific and intraspecific phylogenies and show that the branching patterns follow allometric rules conserved across the different levels in the Tree of Life, all significantly departing from those expected from the standard null models. The finding of non-random universal patterns of phylogenetic differentiation suggests that similar evolutionary forces drive diversification across the broad range of scales, from macro-evolutionary to micro-evolutionary processes, shaping the diversity of life on the planet.
Pretty, but dangerous! Records of non-native Monk Parakeets (Myiopsitta monachus) in Mexico
MacGregor-Fors, Ian;Calderón-Parra, Rafael;Meléndez-Herrada, Alejandro;López-López, Silvia;Schondube, Jorge E.;
Revista mexicana de biodiversidad , 2011,
Abstract: the monk parakeet (myiopsitta monachus) is native to south america and has been introduced by the pet market to several countries around the world. in this note, we compiled records for this species in mexico and report the first sight-recording of this species in the state of michoacán and several nesting localities within the metropolitan area of méxico city. most records are of individuals escaped or released from captivity. also, we review the negative effects that this species has had in invaded areas from around the world. our analysis suggests the possible beginning of an invasion in mexico that could have dramatic negative ecological and economic effects throughout this biodiverse country.
Una propuesta para el monitoreo de la movilidad cortical actual en la sierra Chica de Zonda (Precordillera oriental de San Juan): mediciones de gravedad en red A proposal for monitoring the present crustal mobility in Sierra Chica de Zonda (Eastern Precordillera of San Juan): Gravity measurements in a network
S. Miranda,A. Herrada,J. Sisterna
Revista de la Asociación Geológica Argentina , 2006,
Abstract: Se detallan los requerimientos para el procedimiento de medición de redes precisas de gravedad que permitan obtener una interpretación de los cambios temporales de gravedad observados con relación a movimientos verticales en la corteza. Para Argentina, esta es la primera medición de gravedad en red realizada con fines de monitoreo cortical a escala local. Los vértices de la red prácticamente rodean a la sierra Chica de Zonda (Precordillera Oriental de San Juan) caracterizada como una región de fallamiento activo. El objetivo científico del experimento es el ensayo de esta herramienta geofísica para cuantificar probables deformaciones verticales y/o cambios de masas subsuperficiales vinculados con actividad sísmica. In an attempt to obtain an interpretation of the observed temporal gravity changes related to crustal vertical motions, we describe a methodology using accurate gravity measurements within a fixed network. In Argentina, this is the first gravity survey measured in a network configuration for crustal monitoring studies at a local scale. The network contains the Sierra Chica de Zonda (San Juan Eastern Precordillera), a region of active tectonics. The main goal is to test a geophysical tool useful to quantify probable vertical ground deformations and/or subsurface mass changes associated with seismic activity.
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