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Search Results: 1 - 10 of 55702 matches for " David Valle ? "
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Ojo seco y otros trastornos de la superficie ocular: Diagnóstico y tratamiento en Xerodacriología
David Díaz-Valle
Archivos de la Sociedad Espa?ola de Oftalmología , 2008,
Abstract:
Cornea, Fundamentals, Diagnosis and Management
David Díaz-Valle
Archivos de la Sociedad Espa?ola de Oftalmología , 2005,
Abstract:
Papel del moxifloxacino en la profilaxis de la endoftalmitis posquirúrgica The Role of Moxifloxacin in the Prophylaxis of Post-Surgical Endophthalmitis
Pedro Arriola Villalobos,David Díaz Valle
Archivos de la Sociedad Espa?ola de Oftalmología , 2010,
Abstract:
RECONSTRUCCIóN DE LOS NIVELES DEL RíO ATRATO CON ANILLOS DE CRECIMIENTO DE PRIORIA COPAIFERA
HERRERA,DAVID ANDRéS; DEL VALLE,JORGE IGNACIO;
DYNA , 2011,
Abstract: dendrochronology provides hydroclimatic proxy records in many regions with scarcity of instrumental records. in this paper, we reconstructed the low atrato river′s water levels and assessed the effect of the enso phenomenon in the river level over the past 150 years using the tree rings of prioria copaifera tree (cativo). we demonstrated the annuality of the growth rings by 14c, and by correlations with annual climatic variables. to reconstruct river levels, we used 23 ring width series, and standard dendrochronology methods to cross-dating, detrending, standardize the series, remove the serial autocorrelation, and calculate both arstan and residual chronologies. we found positive and significant association (r=0,589; p<0,01) between water levels and cativo's growth. residual chronology cro4r correlated significant and positively with soi, and the opposite with oni of enso. we found no statistical significant effect on the trend of the atrato river levels over the past 150 years.
Modelación del crecimiento de Albizia niopoides (Mimosaceae) por métodos dendrocronológicos Growth modeling of Albizia niopoides (Mimosaceae) using dendrochronological methods
Víctor David Giraldo,Jorge Ignacio del Valle
Revista de Biología Tropical , 2012,
Abstract: El crecimiento anual de los anillos en los árboles de los bosques tropicales es bastante frecuente y se evidenció en los árboles de Albizia niopoides, que crecen en el ca ón del río Porce, cordillera Central de los Andes colombianos. Se recolectaron 33 secciones transversales de árboles entre 664-870msnm, cortadas a partir de 1.3m de altura del suelo. La hipótesis sobre una periodicidad anual en los anillos fue demostrada mediante cofechado, spaguetti plots y análisis de C14. Para ajustar el diámetro al modelo de crecimiento de Korf se empleó una combinación de análisis descriptivo de series de tiempo (suavizado y pre-whitening); para filtrar el ruido climático y regresión no lineal con residuales ponderados, se alcanzó un coeficiente de determinación cercano al 100%. A pesar de no ser significativa, la autocorrelación serial positiva de orden 1, se explica por la existencia de reservas de energía en el tronco y por la acumulación de los incrementos del diámetro requeridos para la construcción del modelo de crecimiento. Las tasas de crecimiento corriente y medio máximos fueron 1.03 y 0.94cm/a o a las edades de 18 y 46 a os, respectivamente. Albizia niopoides se clasifica dentro del grupo de rápido crecimiento, las cuales pueden alcanzar diámetros de corta de más de 50cm en aproximadamente 52 a os. The annual growth rings in tropical trees are fairly common, but their study is relatively recent. Growth rings were found in trees of Albizia niopoides from the Porce River Canyon, Central Cordillera of the Colombian Andes. A total of 33 cross-sections were collected from trees distributed throughout the study area from 664-870masl. Cross-dating, spaguetti plot and 14C analyses were used to demonstrate ring annuality, assuming as hypothesis that these are real annual growth rings. A combination of descriptive analysis of time series (smoothing and prewhitening) to filter climate noise and nonlinear regression with weighted residuals was used to fit the diameter to Korf′s growth model, in which the coefficient of determination reaches values close to 100%. The positive residual autocorrelation of order 1, although not significant, is explained by the existence of energy reserves in the stem and by the accumulation of diameter increments required for the construction of the diameter growth model. The current and mean annual maximum increment rates are 1.03 and 0.94cm/year at ages 18 and 46 years old, respectively. These trees are classified within the group of fast growing species which can reach a cut diameter of over 50cm in approximately 52 years.
- Las vacunas de ADN: una promisoria medicina para el paciente veterinario (DNA vaccines: a promising medicine for the veterinary patient)
Juan Carlos Díaz David,Maritza Barrera Valle
REDVET , 2006,
Abstract: Resumen. Las vacunas de ADN constituyen una promisoria herramienta en vacunología moderna. Al tratarse de una tecnología fácil de aplicar y de gran versatilidad, capaz de estimular una respuesta inmune humoral y celular, esenciales en la lucha contra infecciones virales, constituye una línea primordial de investigación y desarrollo. Esta revisión aborda las características de un vector de ADN y los mecanismos propuestos para la generación de la respuesta inmune mediante este tipo de vacunación. Igualmente, se discuten algunos regímenes de vacunación, ejemplos de respuestas inmunes protectoras obtenidas en especies de interés veterinario, y se hace referencia a las cuestiones de inocuidad inherentes a este tipo de vacuna. Abstract. DNA vaccines represent an invaluable tool in modern vaccinology. Besides being a simple versatile technology, capable of stimulating both cellular and humoral immune responses, it is also an essential weapon to fight against infections of viral etiology. This review emphasizes the characteristics of a DNA vaccine vector, as well as the proposed mechanisms responsible for the generation of a protective immune response. Furthermore, immunization regimes are discussed, examples of protective immune responses attained in target species of veterinary interest are given and reference is made to the safety concerns derived from this kind of vaccine.
RECONSTRUCCIóN DE LOS NIVELES DEL RíO ATRATO CON ANILLOS DE CRECIMIENTO DE PRIORIA COPAIFERA
DAVID ANDRéS HERRERA,JORGE IGNACIO DEL VALLE
DYNA , 2011,
Abstract: La dendrocronología proporciona registros hidroclimáticos sustitutivos en regiones poco instrumentadas. En este artículo reconstruimos los niveles del bajo río Atrato y evaluamos el efecto del fenómeno ENSO en los últimos 150 a os empleando los anillos de crecimiento de Prioria copaifera (cativo). Demostramos la anualidad de los anillos de crecimiento mediante 14C y correlaciones con variables climáticas anuales. Para la reconstrucción de los niveles del Río empleamos 23 series de ancho de anillos y métodos dendrocronológicos estándar para cofechar, eliminar la tendencia del crecimiento, estandarizar las series eliminar la autocorrelación serial y calcular las cronologías Arstan y Residual. Encontramos asociación positiva y significativa (r=0,589; p<0,01) entre los niveles del Río y el crecimiento del cativo. La cronología residual Cro4R correlacionó significativa y positivamente con SOI y, lo opuesto con ONI del ENSO. No encontramos efecto estadísticamente significativo en la tendencia de los niveles del río Atrato durante los últimos 150 a os.
Prevalencia de sobrepeso y obesidad en escolares de zonas rurales
Coronado Vázquez,Valle; Odero Sobrado,David; Canalejo González,David; Cidoncha Pérez,Jesús;
Gaceta Sanitaria , 2012, DOI: 10.1016/j.gaceta.2011.11.015
Abstract: objectives: to estimate the prevalence of overweight and obesity in schoolchildren in rural areas. methods: a cross-sectional study was carried out in a sample of 1,513 schoolchildren aged 6, 11 and 14 years. data were collected on height and weight with digital scales equipped with a measuring rod. we used three criteria to define overweight and obesity: cole's points, the centers for disease control and prevention (cdc) criteria and hernandez's tables. results: when cole's points were used, 24.6% (95%ci: 22.5 - 26.8) were overweight and 11.6% (95%ci: 10-13.3) were obese; these percentages were higher in children aged 11 and 6 years, respectively. according cdc growth charts, 19.8% of children (95%ci: 17.9-21.9) were overweight and 16.5% (95%ci: 14.7-18.4) were obese, corresponding to higher percentages at 14 and 6 years. when hernandez's tables were used, 11.5% (95%ci: 10-13.2) were overweight and 18.6% (95%ci: 16.7-20.6) were obese, and both disorders were higher in children aged 11 years. the risk of obesity and overweight was higher in small rural areas (<5,000 people), with or = 1.49 (95%ci: 1.13-1.95) and or = 1.33 (95%ci: 1.06-1.67), respectively. conclusions: the prevalence of overweight and obesity in schoolchildren in rural areas is very high and is even higher in towns with less than 5,000 inhabitants.
Experimental Assessment of the Battery Lifetime in WSN Based on the Duty-Cycle Current Average Method  [PDF]
Leonardo Barboni, Maurizio Valle
Wireless Sensor Network (WSN) , 2014, DOI: 10.4236/wsn.2014.610021
Abstract: A great amount of work addressed methods for predicting the battery lifetime in wireless sensor systems. In spite of these efforts, the reported experimental results demonstrate that the duty-cycle current average method, which is widely used to this aim, fails in accurately estimating the battery life time of most of the presented wireless sensor system applications. The aim of this paper is to experimentally assess the duty-cycle current average method in order to give more effective insight on the effectiveness of the method. An electronic metering system, based on a dedicated PCB, has been designed and developed to experimentally measure node current consumption profiles and charge extracted from the battery in two selected case studies. A battery lifetime measurement (during 30 days) has been carried out. Experimental results have been assessed and compared with estimations given by using the duty-cycle current average method. Based on the measurement results, we show that the assumptions on which the method is based do not hold in real operating cases. The rationality of the duty-cycle current average method needs reconsidering.
The Cryo-EM Structure of a Complete 30S Translation Initiation Complex from Escherichia coli
Patricia Julián,Pohl Milon,Xabier Agirrezabala,Gorka Lasso,David Gil,Marina V. Rodnina,Mikel Valle
PLOS Biology , 2012, DOI: 10.1371/journal.pbio.1001095
Abstract: Formation of the 30S initiation complex (30S IC) is an important checkpoint in regulation of gene expression. The selection of mRNA, correct start codon, and the initiator fMet-tRNAfMet requires the presence of three initiation factors (IF1, IF2, IF3) of which IF3 and IF1 control the fidelity of the process, while IF2 recruits fMet-tRNAfMet. Here we present a cryo-EM reconstruction of the complete 30S IC, containing mRNA, fMet-tRNAfMet, IF1, IF2, and IF3. In the 30S IC, IF2 contacts IF1, the 30S subunit shoulder, and the CCA end of fMet-tRNAfMet, which occupies a novel P/I position (P/I1). The N-terminal domain of IF3 contacts the tRNA, whereas the C-terminal domain is bound to the platform of the 30S subunit. Binding of initiation factors and fMet-tRNAfMet induces a rotation of the head relative to the body of the 30S subunit, which is likely to prevail through 50S subunit joining until GTP hydrolysis and dissociation of IF2 take place. The structure provides insights into the mechanism of mRNA selection during translation initiation.
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