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Search Results: 1 - 10 of 155957 matches for " Laura Leiva B "
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Assessing the Performance of Two Hydrologic Models for Forecasting Daily Streamflows in the Cazones River Basin (Mexico)  [PDF]
Fernando González-Leiva, Rodrigo Valdés-Pineda, Juan B. Valdés, Laura A. Ibá?ez-Castillo
Open Journal of Modern Hydrology (OJMH) , 2016, DOI: 10.4236/ojmh.2016.63014
Abstract: Floods have caused significant human and economic losses in the Cazones River Basin, located on the Gulf of Mexico. Despite this knowledge, steps towards the design and implementation of an early warning system for the Cazones are still a pending task. In this study we contributed by establishing a hydrological scheme for forecasting mean daily discharges in the Cazones Basin. For these purposes, we calibrated, validated and compared the HyMod model (HM) which is physics-based, and an autoregressive-based model coupled with the Discrete Kalman Filter (ARX-DKF). The ability of both models to accurately predict discharges proved satisfactory results during the validation period with RMSEHYMOD = 2.77 [mm/day]; and RMSEARX-DKF = [2.38 mm/day]. Further analysis based on a Streamflow Assimilation Ratio (SAR) revealed that both models underestimate the discharges in a similar proportion. This evaluation also showed that, under the most common conditions, the simpler stochastic model (ARX-DKF) performs better; however, under extreme hydrological conditions the deterministic HM model reveals a better performance. These results are discussed under the context of future applications and additional requirements needed to implement an early warning hydrologic system for the Cazones Basin.
APORTE DEL PAN A LA NUTRICION DE YODO DEL ESCOLAR CHILENO
Leiva B,Laura; Braverman,Lewis; Muzzo B,Santiago;
Revista chilena de nutrición , 2002, DOI: 10.4067/S0717-75182002000100009
Abstract: the evolution of iodine nutrition in chilean school age children belonging to 4 censorial areas is described. the excesive urinary iodine excretion, in spite that food sanitary regulations decreased iodine concentration in salt from 100 to a range of 20 to 60 ppm, is noted. we were interested in studying why iodine in urine did not decreased. iodine content in bread was measured due to its high intake in chile (250 ug/day). iodine concentration in different types of breads was around 0.5 ug/g, a value 10 times the determinations done in england and spain. however it was estimated that bread consumption in chile contributed around 130 ug i/ day, which does not explain completely current high urinary iodine excretions. it is important continue searching the cause of this high intake to avoid posible complications.
MASA óSEA MáXIMA DE ADULTOS JOVENES CHILENOS COMPARADA CON LOS VALORES DE LA LUNAR
Muzzo B.,Santiago; Leiva B.,Laura; Ramirez M.,Ivan;
Revista chilena de nutrición , 2003, DOI: 10.4067/S0717-75182003000100007
Abstract: achievement of a high peak bone mass (pbm) in the young adult constitute the most important safeguard to prevent bone mineralization (bm) problems of the elderly. we were interested to know if young healthy chilean adults, with all the positive factors that favors a normal bm, had a pbm similar to the lunar's reference values, that are used to determine the adequation of bm in lunar's densitometers. twelve men and 11 women, 27 to 29 years of age were studied. bone mineral density (bmd) of whole body, spine and hips were determined with a lunar-dexa densitometer. no significant differences were found in bmd of whole body, spine and hips of this young chilean adults compared with lunar's reference values. these results point out that lunar's references values can be used as the gold standard to achieve early in the adult life in order to prevent osteoporosis
Peso, talla y perímetro craneano de escolares de la Región Metropolitana de Chile, de acuerdo al nivel socioeconómico Weight, height and skull circumference of school age children from the Metropolitan Region of Chile, according to socioeconomic level
Raquel Burrows A,Laura Leiva B,Santiago Muzzo B
Revista chilena de pediatría , 1992,
Abstract:
Perímetro, áreas magra y grasa braquiales, pliegue tricipital y nivel socioeconómico en escolares de la Región Metropolitana de Chile Brachial circumference, lean and fat area, triceps skin fold and socioeconomic condition in school children
Raquel Burrows A,Laura Leiva B,Santiago Muzzo B
Revista chilena de pediatría , 1993,
Abstract:
MASA óSEA MáXIMA DE ADULTOS JOVENES CHILENOS COMPARADA CON LOS VALORES DE LA LUNAR PEAK BONE MASS VALUES OF YOUNG CHILEAN ADULTS COMPARED WITH LUNAR′S VALUES
Santiago Muzzo B.,Laura Leiva B.,Ivan Ramirez M.
Revista Chilena de Nutricíon , 2003,
Abstract: La masa ósea máxima (MOM) del adulto joven constituye el capital de reserva para prevenir trastornos de la mineralización ósea (MO) en la vida de adulto mayor. Nos interesó conocer si adultos jóvenes chilenos, sanos y que reunieran todos los factores favorecedores de una adecuada MO, tenían una MOM similar a los valores de referencia de los densitómetros LUNAR, que se usan para determinar la adecuación de la MO. Se estudiaron 23 jóvenes cuyas edades fluctuaron entre 27 y 29 a os (12 varones y 11 mujeres), a los cuales se les determinó la densidad mineral ósea (DMO) en cuerpo entero, columna y caderas con un densitómetro LUNAR-DEXA. No se encontraron diferencias significativas entre los valores determinados en estos adultos jóvenes chilenos con los valores de referencia de la LUNAR. Estos resultados indicarían que los valores de MOM de la LUNAR pueden usarse como meta a obtener especialmente en programas de prevención de osteoporosis Achievement of a high peak bone mass (PBM) in the young adult constitute the most important safeguard to prevent bone mineralization (BM) problems of the elderly. We were interested to know if young healthy Chilean adults, with all the positive factors that favors a normal BM, had a PBM similar to the Lunar's reference values, that are used to determine the adequation of BM in Lunar's densitometers. Twelve men and 11 women, 27 to 29 years of age were studied. Bone mineral density (BMD) of whole body, spine and hips were determined with a LUNAR-DEXA densitometer. No significant differences were found in BMD of whole body, spine and hips of this young Chilean adults compared with Lunar's reference values. These results point out that Lunar's references values can be used as the gold standard to achieve early in the adult life in order to prevent osteoporosis
APORTE DEL PAN A LA NUTRICION DE YODO DEL ESCOLAR CHILENO CONTRIBUTION OF BREAD TO IODINE INTAKE IN CHILEAN SCHOOL CHILDREN
Laura Leiva B,Lewis Braverman,Santiago Muzzo B
Revista Chilena de Nutricíon , 2002,
Abstract: Se describe la evolución de la nutrición de yodo en el escolar chileno perteneciente a 4 zonas censorias del país, destacando la excesiva excreción urinaria de yodo a pesar que el Reglamento Sanitario de los Alimentos disminuyó el a o 2000 la concentración de yodo en la sal de 100 ppm a un rango de 20 a 60 ppm. Nos interesó estudiar porque no disminuyeron las yodurias en los escolares. Para ello se midió el contenido de yodo en el pan, por tener un alto consumo en Chile (en promedio 250 g por día). En diferentes tipos de pan se determinó la concentración de yodo que fue alrededor de 0.5 ug /g, valor 10 veces mas alta que en mediciones efectuadas en Inglaterra y Espa a. Sin embargo se estimó que el consumo de pan en Chile aportaría alrededor de 130 ug I/día, lo que no explicaría totalmente las altas cifras de excreción de yodo actuales. De importancia es continuar indagando las causas de este alto consumo para evitar sus posibles complicaciones The evolution of iodine nutrition in chilean school age children belonging to 4 censorial areas is described. The excesive urinary iodine excretion, in spite that Food Sanitary regulations decreased iodine concentration in salt from 100 to a range of 20 to 60 ppm, is noted. We were interested in studying why iodine in urine did not decreased. Iodine content in bread was measured due to its high intake in Chile (250 ug/day). Iodine concentration in different types of breads was around 0.5 ug/g, a value 10 times the determinations done in England and Spain. However it was estimated that bread consumption in Chile contributed around 130 ug I/ day, which does not explain completely current high urinary iodine excretions. It is important continue searching the cause of this high intake to avoid posible complications.
SENSIBILIDAD DE DIFERENTES ESTáNDARES PARA DETECTAR LOS TRASTORNOS METABóLICOS EN NI?OS CON EXCESO DE PESO
Burrows A.,Raquel; Burgue?o A.,Medardo; Leiva B.,Laura;
Revista chilena de nutrición , 2003, DOI: 10.4067/S0717-75182003000100004
Abstract: childhood obesity is associated with a high prevalence of metabolic disturbances (md) which precede type 2 diabetes and ischemic cardiopaties. early detection and correction would allow to decrease morbimortality from these diseases. dyslipidemia and insulin resistance are related with the amount of total body fat (tbf), showing a higher risk when is > 30%. the most used standards to define obesity in people < 18 years of age are the cdc-nchs (usa), which describes as obesity a body mass index (bmi) > p95 and the international obesity task force (iotf) standards whose definition is based on the bmi, regressively calculated from bmi 30 kg/m2 at 18 years old. both standards are supported on a statistical criteria. the objective of this study was to compare the sensitivity of the cut-off points of these two standards and the 30% of tbf and relate them to the md associated to obesity, with the intention to give a more biological than statistical diagnosis. in 259 overweight children from both sexes, aged 5 to 17 yeras old total cholesterol (tc), ldl cholesterol (ldl-chol) basal insulinemia (biins) and 2 hours post oral glucosa administration (2h ins) was measured. with simple contingency tables, chi2, odds ratio, sensitivity and specificity was calculated. there was 25% of total hypercholesterolemia, 24,2% of elevated ldl chol, 20,5% and 39,5% of high basal ins and 2h ins respectively. the prevalence of obesity and/or overweight was significantly associated (p < 0.000) to the standard used to qualify them. no association was found between the amount of weight excess and the risk of dyslipidemia or hyperinsulinism after a glucose load when cdc/nchs and iotf were used. in obese children the basal hyperinsulinism was higher than in non-obese. the cut-off point > 30% of tbf showed the higher sensitivity and statistical validation for the detection of the basal and post glucose load hyperinsulinism
SENSIBILIDAD DE DIFERENTES ESTáNDARES PARA DETECTAR LOS TRASTORNOS METABóLICOS EN NI OS CON EXCESO DE PESO SENSITIVITY OF VARIOUS STANDARDS FOR DETECTION OF METABOLIC DISTRUBANCE IN OVERWEIGHT CHILDREN
Raquel Burrows A.,Medardo Burgue?o A.,Laura Leiva B.
Revista Chilena de Nutricíon , 2003,
Abstract: La obesidad infantil se asocia a una alta prevalencia de trastornos metabólicos (TM) que preceden a la Diabetes Mellitus tipo 2 y a la cardiopatía isquémica. Detectarlos y corregirlos tempranamente permitiría disminuir la morbimortalidad por estas enfermedades. La dislipidemia y la resistencia insulínica se relacionan con la cantidad de grasa corporal total (GCT), describiéndose un mayor riesgo biológico cuando es igual o mayor al 30 %. Para calificar el sobrepeso en el menor de 18 a os la OMS recomienda el Indice de Masa Corporal (IMC). Los referentes más utilizados son los del CDC-NCHS (USA) que califica como obesidad al IMC p95 y el del International Obesity Task Force (IOTF), cuya calificación de obesidad se basa en los IMC calculados regresivamente a partir de una población que a los 18 ańos tenía un IMC 30; ambos estándares se apoyan en un criterio estadístico. El propósito de este estudio fue comparar la sensibilidad de los puntos de cortes que califican obesidad de estos 2 estándares y del 30 % GCT, para pesquizar los trastornos metabólicos asociados a la obesidad, con el objeto de aportar antecedentes que permitan realizar un diagnóstico más biológico que estadístico. En 259 ni os con sobrepeso de ambos sexos entre 5 y 17 a os, se midió el colesterol total (CT), el colesterol LDL (Col-LDL), la insulinemia basal (Ins bas ) y 2 horas post sobrecarga de glucosa (Ins 2 hrs). Se calificó el exceso de peso utilizando los estándares CDC/NCHS e IOTF y el % GCT. Por tablas de contingencia simple, Chi2 y Odds Ratio (OR) R se evaluó la validez, la sensibilidad y la especificidad para pesquisar los trastornos metabólicos de estos tres criterios. Hubo un 25 % de hiper CT, un 24,2 % de hipercol- LDL, un 20,5 % de hiper Ins b y 39,5 % de hiper Ins 2h. La prevalencia de obesidad y/o sobrepeso se asoció significativamente (p < 0.000) al criterio utilizado para calificarlos. No se encontró asociación entre la calidad del exceso ponderal y el riesgo de dislipidemia, ni hipersinsulinismo post sobrecarga al utilizar los estandares CDC-NCHS e IOTF. En los obesos el riesgo de hipersinsulinismo basal fue 4.8 y 4.5 veces mayor respectivamente. El punto de corte 30% GCT mostró la mayor sensibilidad y validez estadística para la pesquiza del hiperinsulinismo tanto basal como postsobrecarga de glucosa Childhood obesity is associated with a high prevalence of metabolic disturbances (MD) which precede type 2 diabetes and ischemic cardiopaties. Early detection and correction would allow to decrease morbimortality from these diseases. Dyslipidemia and insulin resistance ar
Crecimiento y desarrollo de hijos de adolescentes de clase media-baja. II Parte: 30 meses de vida Growth and development in children from teenage's mothers
Raquel Burrows A,Laura Leiva B,Ruperto Bravo B,Laura Macho F
Revista chilena de pediatría , 1986,
Abstract:
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