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Search Results: 1 - 10 of 33298 matches for " Daniel Pizarro "
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Dengue, Dengue hemorrágico
Pizarro,Daniel;
Acta Pediátrica Costarricense , 2009,
Abstract: el dengue ó fiebre por dengue, es una enfermedad febril producida por uno de los cuatro serotipos del virus dengue, que pertenecen al grupo de virus transmitidos por artrópodos (arthropod-borne-virus ó arbovirus). la transmisión se hace por medio de la hembra del mosquito aedes aegypti, que pertenece al género flavivirus de la familia flaviridae. el dengue es la enfermedad transmitida por vectores más frecuente en todo el mundo. desde 1993 en costa rica el dengue es una enfermedad endémica en las costas del océano pacífico y del mar caribe. durante estos a?os y hasta el 8 de septiembre del 2007 la prevalencia de dengue clásico es de 4.087 casos por 100.000 habitantes, de dengue hemorrágico 14 casos por 100.000 habitantes para una tasa de letalidad por dengue hemorrágico de 0.02%. entre la inoculación del virus por la mosquita aedes y la aparición de los síntomas hay un lapso de 3 á 14 días, en promedio 7 días. es el período de incubación de la enfermedad. existen 4 grupos antigénicos o serotipos de virus del dengue: den-1, den-2, den- 3 y den-4. el den-1 tiene sólo 7 biotipos, y el den-2, 34 biotipos. las hemorragias que se producen en el dengue son el producto de las lesiones en el endotelio vascular, de la trombocitopenia, de la disfunción de las plaquetas y de la alteración de los factores de coagulación. la lesión de las "esclusas" de la zonula occludens provoca un escape de líquidos del espacio intra-vascular al espacio extra-vascular. la hipovolemia desencadena una serie de respuestas homeostáticas que tienen como fin mantener una mejor perfusión de los órganos más nobles de la economía en detrimento de otros órganos como son la piel y los músculos. el periodo febril dura de 3 á 7 días, y el día de la defervescencia (día cero) el paciente evolucionará hacia la convalecencia ó hacia el dengue hemorrágico. en los primeros días suele aparecer exantema generalizado, con palidez de la piel al hacer presión sobre ella. las manos y pies se tornan hiperhémicos y en la
Alteraciones hidroelectrolíticas y ácido-base más frecuentes en el paciente con diarrea
Pizarro-Torres, Daniel;
Boletín médico del Hospital Infantil de México , 2005,
Abstract: normonatremic dehydration is by far the most common electrolyte imbalance. hyponatremic and hypernatremic dehydration are less frequent and are caused by offering the patient hypotonic fluid in cases presenting hyponatremic dehydration or hypertonic and/or fluid containing high sodium concentration in cases presenting hypernatremic dehydration. dehydration promotes vasoconstriction. intravascular space contraction causes tissue hypoxia. the aerobic atp production in mitochondria diminishes, the glycolytic atp production is enhanced and its consumption yields high hydrogen and lactate concentration, causing acidemia. the production of activated oxygen species (aos) increases in systemic arteries and diminishes in pulmonary arterioles. acidemia and aos open katp in systemic arteries. potassium extrusion causes hyperpotassemia, hyperpolarization of miocytes and vasodilatation. in pulmonary arterioles acidemia and diminishing in aos release cause closure of kv, membrane depolarization and pulmonary vasoconstriction. acidemia causes opening of cl-c2 chloride channels and outward rectification. imbalance in calcium, phosphate and magnesium is minimum. oral or intravenous rehydration with balanced polyelectrolytic rehydration solution rehydrates successfully the diarrheic dehydrated patients presenting electrolyte and acid-base imbalance.
Análisis del cumplimiento de la normativa estatal sobre la evaluación de impacto ambiental para proyectos de grandes presas
Pizarro Camacho, Daniel,Soca Olazábal, Nely
Informes de la Construccion , 2001,
Abstract: The purpose of this work consists on specifying through un analysis of the DIA emitted in Spain, for the projects of large dams. which are the most significant aspects that are considered, how the studies of environmental impact presented are assess and what deficiencies or adaptation lack fo the evaluation procedure are detected. We concludes with some proposals in order to improve the procedure in the elaboration of the DIA according lo appropriate execution of that are specifed in the state environmental normative. En nuestro trabajo se realiza un análisis de las declaraciones de impacto ambiental (DIA) hechas públicas en el BOE desde 1990 al 2001, sobre proyectos de grandes presas. Se puede observar el incumplimiento del articulado sobre el contenido del Estudio de Impacto Ambiental especificado en el Reglamento 1131/1988, de 30 de septiembre, que se detalla en el trabajo. Asimismo se analizan las deficiencias encontradas en las DIA, documento de gran importancia en la aprobación y especificación de los condicionantes necesarios para que el desarrollo del proyecto no cause un impacto irreparable.
Source Localization with Acoustic Sensor Arrays Using Generative Model Based Fitting with Sparse Constraints
Jose Velasco,Daniel Pizarro,Javier Macias-Guarasa
Sensors , 2012, DOI: 10.3390/s121013781
Abstract: This paper presents a novel approach for indoor acoustic source localization using sensor arrays. The proposed solution starts by defining a generative model, designed to explain the acoustic power maps obtained by Steered Response Power (SRP) strategies. An optimization approach is then proposed to fit the model to real input SRP data and estimate the position of the acoustic source. Adequately fitting the model to real SRP data, where noise and other unmodelled effects distort the ideal signal, is the core contribution of the paper. Two basic strategies in the optimization are proposed. First, sparse constraints in the parameters of the model are included, enforcing the number of simultaneous active sources to be limited. Second, subspace analysis is used to filter out portions of the input signal that cannot be explained by the model. Experimental results on a realistic speech database show statistically significant localization error reductions of up to 30% when compared with the SRP-PHAT strategies.
Diversidad taxonómica y denso-actividad de solífugos (Arachnida: Solifugae) asociados a un ecosistema desértico costero del centro norte de Chile
Valdivia,Daniel E.; Pizarro-Araya,Jaime; Cepeda-Pizarro,Jorge; Ojanguren-Affilastro,Andrés A.;
Revista de la Sociedad Entomol?3gica Argentina , 2008,
Abstract: in chile the order solifugae is represented by 14 species arranged in 10 genera distributed among the three families described for south america: ammotrechidae, mummuciidae and daesiidae. the present work documents the taxonomic composition of solpugids in a desert coastal ecosystem of the northern centre of chile and describes variation in their density-activity. the study was carried out in the coastal sector of punta de choros (29°21's, 71°10'w; 17 masl) during june, august, october and november 2005. the 249 captured specimens represented three families, four genera, and five species. these were procleobis sp. and sedna pirata muma (ammotrechidae), mummucia sp. and mummucia variegata (gervais) (mummuciidae), and ammotrechelis goetschi roewer (daesiidae). the highest levels of solpugid density-activity occurred in october (ca 30 % of the total captured) and november (ca 41 % of the total captured). five species were captured in october and three, in november. while some species were active throughout the study (e.g., ammotrechelis goetschi), others showed occasional activity. for example, mummucia variegata showed activity between august and november, sedna pirata between october and november, and procleobis sp. and mummucia sp. only in october. the diversity and density-activity may be determined by biological and ecological factors.
Species composition and abundance of solpugids (Arachnida: Solifugae) in ecotopes of the transitional coastal desert of Chile
Valdivia, Daniel Eugenio;Pizarro-Araya, Jaime;Briones, Raúl;Ojanguren-Affilastro, Andrés A.;Cepeda-Pizarro, Jorge;
Revista mexicana de biodiversidad , 2011,
Abstract: using pitfall traps, the species composition and abundance of solpugids were studied in several ecotopes of chile's transitional coastal desert. the study was conducted in the area around punta de choros (29°15's, 71°26'w) and in los choros archipelago (29°32's, 67°61'w), in 2005 and 2006. five species were recorded: procleobis sp.; sedna pirata muma, 1971 (ammotrechidae); mummucia sp.; mummucia variegata (gervais, 1849) (mummuciidae); and ammotrechelis goetschi roewer, 1934 (daesiidae). solpugid abundance was higher on the continent (65%) than on the islands (35%). the anosim used to evaluate any difference in species richness between ecotopes revealed no significant differences (r= 0.097, p= 0.13). the similarity dendrogram obtained from the bray-curtis matrix indicates that there are 3 groups of ecotopes: steppe, dune, and a miscellaneous group. from the data it is inferred that the diversity and abundance of solpugids in the ecotopes studied may be related to plant structure and to the pedological conditions of the habitat.
Diversidad taxonómica y denso-actividad de solífugos (Arachnida: Solifugae) asociados a un ecosistema desértico costero del centro norte de Chile Taxonomic diversity and density-activity of solpugids (Arachnida: Solifugae) in a coastal desert ecosystem in the northern centre of Chile
Daniel E. Valdivia,Jaime Pizarro-Araya,Jorge Cepeda-Pizarro,Andrés A. Ojanguren-Affilastro
Revista de la Sociedad Entomol?3gica Argentina , 2008,
Abstract: En Chile, el orden Solifugae está representado por 14 especies agrupadas en 10 géneros, distribuidos en las tres familias descritas en Sudamérica: Ammotrechidae, Mummuciidae y Daesiidae. En el presente trabajo se documenta la composición genérica y/o específica de solífugos asociados a un ecosistema desértico costero del centro norte de Chile, y se muestran las variaciones de su denso-actividad. El estudio se realizó en el sector costero de Punta de Choros (29°21'S, 71°10'O; 17 msnm), durante los meses de junio, agosto, octubre y noviembre de 2005. Entre los 249 ejemplares capturados, se reconoció la presencia de tres familias, cuatro géneros y cinco especies. éstas fueron Procleobis sp., Sedna pirata Muma (Ammotrechidae), Mummucia sp., Mummucia variegata (Gervais) (Mummuciidae) y Ammotrechelis goetschi Roewer (Daesiidae). La mayor denso-actividad de solífugos se registró en los meses de octubre, 5 especies (ca 30 % del total capturado); y noviembre, 3 especies (ca 41 % del total capturado). Mientras que algunas especies se mostraron activas durante todo el período de estudio (e.g., Ammotrechelis goetschi), otras presentaron actividad parcial. Por ejemplo, Mummucia variegata manifestó actividad entre agosto y noviembre; Sedna pirata entre octubre y noviembre y tanto Procleobis sp. como Mummucia sp. estuvieron activas sólo en octubre. La diversidad y la denso-actividad de Solifugae estarían determinadas por factores biológicos y ecológicos. In Chile the order Solifugae is represented by 14 species arranged in 10 genera distributed among the three families described for South America: Ammotrechidae, Mummuciidae and Daesiidae. The present work documents the taxonomic composition of solpugids in a desert coastal ecosystem of the northern centre of Chile and describes variation in their density-activity. The study was carried out in the coastal sector of Punta de Choros (29°21'S, 71°10'W; 17 masl) during June, August, October and November 2005. The 249 captured specimens represented three families, four genera, and five species. These were Procleobis sp. and Sedna pirata Muma (Ammotrechidae), Mummucia sp. and Mummucia variegata (Gervais) (Mummuciidae), and Ammotrechelis goetschi Roewer (Daesiidae). The highest levels of solpugid density-activity occurred in October (ca 30 % of the total captured) and November (ca 41 % of the total captured). Five species were captured in October and three, in November. While some species were active throughout the study (e.g., Ammotrechelis goetschi), others showed occasional activity. For example, Mummucia variegata showed
Spatial Structure and Activity of Sedimentary Microbial Communities Underlying a Beggiatoa spp. Mat in a Gulf of Mexico Hydrocarbon Seep
Karen G. Lloyd,Daniel B. Albert,Jennifer F. Biddle,Jeffrey P. Chanton,Oscar Pizarro,Andreas Teske
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0008738
Abstract: Subsurface fluids from deep-sea hydrocarbon seeps undergo methane- and sulfur-cycling microbial transformations near the sediment surface. Hydrocarbon seep habitats are naturally patchy, with a mosaic of active seep sediments and non-seep sediments. Microbial community shifts and changing activity patterns on small spatial scales from seep to non-seep sediment remain to be examined in a comprehensive habitat study.
GPCA vs. PCA in Recognition and 3-D Localization of Ultrasound Reflectors
Carlos A. Luna,José A. Jiménez,Daniel Pizarro,Cristina Losada,José M. Rodriguez
Sensors , 2010, DOI: 10.3390/s100504825
Abstract: In this paper, a new method of classification and localization of reflectors, using the time-of-flight (TOF) data obtained from ultrasonic transducers, is presented. The method of classification and localization is based on Generalized Principal Component Analysis (GPCA) applied to the TOF values obtained from a sensor that contains four ultrasound emitters and 16 receivers. Since PCA works with vectorized representations of TOF, it does not take into account the spatial locality of receivers. The GPCA works with two-dimensional representations of TOF, taking into account information on the spatial position of the receivers. This report includes a detailed description of the method of classification and localization and the results of achieved tests with three types of reflectors in 3-D environments: planes, edges, and corners. The results in terms of processing time, classification and localization were very satisfactory for the reflectors located in the range of 50–350 cm.
Odometry and Laser Scanner Fusion Based on a Discrete Extended Kalman Filter for Robotic Platooning Guidance
Felipe Espinosa,Carlos Santos,Marta Marrón-Romera,Daniel Pizarro,Fernando Valdés,Javier Dongil
Sensors , 2011, DOI: 10.3390/s110908339
Abstract: This paper describes a relative localization system used to achieve the navigation of a convoy of robotic units in indoor environments. This positioning system is carried out fusing two sensorial sources: (a) an odometric system and (b) a laser scanner together with artificial landmarks located on top of the units. The laser source allows one to compensate the cumulative error inherent to dead-reckoning; whereas the odometry source provides less pose uncertainty in short trajectories. A discrete Extended Kalman Filter, customized for this application, is used in order to accomplish this aim under real time constraints. Different experimental results with a convoy of Pioneer P3-DX units tracking non-linear trajectories are shown. The paper shows that a simple setup based on low cost laser range systems and robot built-in odometry sensors is able to give a high degree of robustness and accuracy to the relative localization problem of convoy units for indoor applications.
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