Aplicación de una ecuación de flujo subterráneo equivalente para medios heterogéneos : Avances preliminares

En este trabajo se evaluó numéricamente la aplicabilidad de un modelo matemático de flujo equivalente en medios saturados basado en una formulación de no equilibrio mediante un término adicional de transferencia de masa a tasa múltiple (Multi-Rate Mass Transfer, MRMT). En campos de transmisividad generados a partir de modelos geoestadísticos estacionarios se simularon numéricamente ensayos de bombeo resolviendo la ecuación de flujo clásica en régimen transitorio, cuyos resultados fueron considerados la respuesta “observada”. Luego se resolvió la ecuación de flujo radial equivalente mediante un código escrito en Fortran 90 donde el término de transferencia de masa o Función de Memoria considera conceptualmente N zonas inmóviles acopladas a cada celda del dominio de cálculo. Ajustes preliminares del modelo equivalente a los descensos observados demuestran que la formulación de no equilibrio podría constituir una buena alternativa para representar el drenaje diferido asociado a la estructura de la variabilidad espacial de la transmisividad de acuíferos.In this paper, the applicability of an equivalent groundwater flow equation, based on non-equilibrium fo rmulation by an additional term of Multi-Rate Mass Transfer (MRMT), was numerically evaluated. Pumping tests in transmissivity fields generated from stationary geostatistical models were numerically simulated by solving the classical transient flow equation and the results were considered the "observed" response. On other hand, it was solved the equivalent radial flow equation by a code written in Fortran 90 where the mass transfer term memory function considers conceptually N immobile zones coupled to each cell in the computational domain. Preliminary adjustments of the equivalent model to the observed drawdowns show that non-equilibrium formulation could be a good alternative to represent delayed drainage associated with associated with the aquifer transmissivity spatial variability.Universidad Nacional de La Plat

Relación cartográfica entre variables hidrológicas y de degradación por pérdida de suelo superficial: sitio piloto A° Estacas, Entre Ríos

El aumento del área agrícola en el norte de la provincia de Entre Ríos resulta de la pérdida del bosque nativo. Este cambio del uso del suelo impacta los servicios ecosistémicos que brindan las cuencas hidrográficas, e incrementa el riesgo de degradación y pérdida de suelo por erosión. Actualmente el límite de pérdida de suelo utilizado para diseñar prácticas de sistematización de tierras es 15 Mg.ha-1.año-1, valor tres veces mayor al umbral para una producción sustentable. Este trabajo relaciona la cartografía de variables hidro­lógicas y pérdida de suelos para localizar y caracterizar áreas vulnerables a la erosión hídrica, como herra­mientas de ordenamiento territorial de cuencas. Se usaron los parámetros de curva número (CN), índice to­pográfico (TCI) y la ecuación USLE. Se trabajó en un entorno SIG en la cuenca del A° Estacas, con resolución espacial de 30 metros. Las imágenes fueron referenciadas al sistema POSGAR 2007 – FAJA 5. Como datos de entrada se utilizó: MDE ALOS PALSAR, carta de suelos de la provincia a escala 1:100.000, precipitación media anual, e imágenes Landsat 8. Se realizaron estadísticas por composición de mapas, gráficos de densidad por Kernel y ajuste por estimadores de máxima verosimilitud. Se observó que la pérdida de suelo se incrementa directamente con la generación de escurrimiento (CN), e inversamente con la probabilidad de encharcamiento (TCI). La cartografía generada verificó que reducir el umbral de pérdida de suelo a 3 Mg.ha-1.año-1 es factible como límite para una producción sustentable en la cuenca, independientemente del uso de suelo. Se definieron sectores que requieren una rápida acción correctiva, donde las pérdidas de suelo superan las 15 Mg.ha-1.año-1. Además, se identificaron áreas vulnerables entre 5 y 15 Mg.ha-1.año-1, tanto bajo uso agrícola como ganadero, donde se necesita revisar la intervención.Expansion of agricultural land use in the north of Entre Ríos province diminishes land occupied by native forests. At watershed scale, this change in land use impacts the provision of ecosystem services and increases soil´s degradation and water erosion. Current limit of soil loss for design of terraces is 15 Mg.ha-1. yr-1, three times larger than FAO threshold for sustainable agricultural production. In this work the mapping of hydrological variables and soil loss is combined to determine and characterize vulnerable areas to soil water erosion, as tools for watershed land use planning. The parameters of curve number (CN), topographic index (TCI) and the USLE equation were used. Work was carried out in a GIS environment in the A° Estacas watershed, with a spatial resolution of 30 meters. The images were referenced to the POSGAR 2007 - FAJA 5 system. The input data used were: ALOS PALSAR DEM, soil map of the province at a scale of 1:100,000, average annual precipitation, and Landsat 8 images. Statistical methods included univariate analyses, Kernel density distribution, and máximum likelihood. Soil loss increased directly with runoff generation (CN), and inversely with the probability of waterlogging (TCI). The generated mapping verified that regardless of land use, it is feasible to reduce the soil loss threshold for sustainable production in the basin to 3 Mg.ha-1. yr-1. The proposed mapping defined areas requiring rapid corrective actions, where estimated soil losses exceeded 15 Mg.ha-1.yr-1. In addition, the mapping allowed to localize vulnerable areas within the watershed, with soil loss between 5 and 15 Mg.ha-1.yr-1, under agricultural and livestock use, where their intervention should be reviewed.EEA ParanáFil: Pighini, Ramiro Joaquin. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Wingeyer, Ana. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Paraná; ArgentinaFil: Rodríguez, Leticia B. Universidad Nacional del Litoral. Facultad de Ingeniería y Ciencias Hídricas. Centro de Estudios Hidro-ambientales; ArgentinaFil: Wilson, Marcelo G. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Paraná; ArgentinaFil: Gabioud, Emmanuel. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Paraná; ArgentinaFil: Van Opstal, Natalia. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Paraná; Argentin

Water stress and temperature effects on germination and early seedling growth of Digitaria eriantha

This study focused on the two major processes critical for plant establishment: Seed germination and seedling survival. We determined the effects of (1) water stress and temperature on the germination, and (2) water stress on early seedling growth of Digitaria eriantha cv ‘Irene’. Seeds harvested in 2007 were used for temperature studies, and those coming from 2006 and 2007 for water stress studies. In 2009, viability decreased by 65.4% from 2006 to 2007. During the first twenty-four hours, germination was more than 50% at constant (30 or 35°C) than alternating (10/30 or 10/35°C) temperatures, although total germination was about 80% for all temperature treatments. Polyethylene glycol 8000 was used to impose water stress conditions. Germination percentages and coefficients of velocity decreased with decreasing water potentials. Early seedling growth was smaller at lower water potentials. D. eriantha cv ‘Irene’ appeared to germinate within a wide range of temperatures, but it varied greatly in germination response to water potentials. Results suggest that this species could be planted in late spring-early summer, when seedbed temperatures are increasing and soil moisture might still be adequate.Fil: Brevedan, Roberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida(i); Argentina. Universidad Nacional del Sur. Departamento de Agronomía; ArgentinaFil: Busso, Carlos Alberto. Universidad Nacional del Sur. Departamento de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida(i); ArgentinaFil: Fioretti, M. N.. Universidad Nacional del Sur. Departamento de Agronomía; ArgentinaFil: Toribio, M. B.. Universidad Nacional del Sur. Departamento de Agronomía; ArgentinaFil: Baioni, S. S.. Universidad Nacional del Sur. Departamento de Agronomía; ArgentinaFil: Torres, Yanina Alejandra. Universidad Nacional del Sur. Departamento de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida(i); ArgentinaFil: Fernandez, Osvaldo Alberto. Universidad Nacional del Sur. Departamento de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida(i); ArgentinaFil: Giorgetti, H. D.. Provincia de Buenos Aires. Ministerio de Asuntos Agrarios. Chacra Experimental de Patagones; ArgentinaFil: Bentivegna, Diego Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida(i); ArgentinaFil: Entío, J.. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales; ArgentinaFil: Ithurrart, Leticia Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida(i); Argentina. Universidad Nacional del Sur. Departamento de Agronomía; ArgentinaFil: Montenegro, O.. Provincia de Buenos Aires. Ministerio de Asuntos Agrarios. Chacra Experimental de Patagones; ArgentinaFil: Mujica, M. de las M.. Universidad Nacional de La Plata. Facultad de Ciencias Agrarias y Forestales; ArgentinaFil: Rodríguez, G.. Provincia de Buenos Aires. Ministerio de Asuntos Agrarios. Chacra Experimental de Patagones; ArgentinaFil: Tucat, Guillermo. Universidad Nacional del Sur. Departamento de Agronomía; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Bahía Blanca. Centro de Recursos Naturales Renovables de la Zona Semiárida(i); Argentin

Water stress and temperature effects on germination and early seedling growth of <i>Digitaria eriantha</i>

This study focused on the two major processes critical for plant establishment: Seed germination and seedling survival. We determined the effects of (1) water stress and temperature on the germination, and (2) water stress on early seedling growth of Digitaria eriantha cv ‘Irene’. Seeds harvested in 2007 were used for temperature studies, and those coming from 2006 and 2007 for water stress studies. In 2009, viability decreased by 65.4% from 2006 to 2007. During the first twenty-four hours, germination was more than 50% at constant (30 or 35°C) than alternating (10/30 or 10/35°C) temperatures, although total germination was about 80% for all temperature treatments. Polyethylene glycol 8000 was used to impose water stress conditions. Germination percentages and coefficients of velocity decreased with decreasing water potentials. Early seedling growth was smaller at lower water potentials. D. eriantha cv ‘Irene’ appeared to germinate within a wide range of temperatures, but it varied greatly in germination response to water potentials. Results suggest that this species could be planted in late spring-early summer, when seedbed temperatures are increasing and soil moisture might still be adequate.Facultad de Ciencias Agrarias y Forestale

Water stress and temperature effects on germination and early seedling growth of <i>Digitaria eriantha</i>

This study focused on the two major processes critical for plant establishment: Seed germination and seedling survival. We determined the effects of (1) water stress and temperature on the germination, and (2) water stress on early seedling growth of Digitaria eriantha cv ‘Irene’. Seeds harvested in 2007 were used for temperature studies, and those coming from 2006 and 2007 for water stress studies. In 2009, viability decreased by 65.4% from 2006 to 2007. During the first twenty-four hours, germination was more than 50% at constant (30 or 35°C) than alternating (10/30 or 10/35°C) temperatures, although total germination was about 80% for all temperature treatments. Polyethylene glycol 8000 was used to impose water stress conditions. Germination percentages and coefficients of velocity decreased with decreasing water potentials. Early seedling growth was smaller at lower water potentials. D. eriantha cv ‘Irene’ appeared to germinate within a wide range of temperatures, but it varied greatly in germination response to water potentials. Results suggest that this species could be planted in late spring-early summer, when seedbed temperatures are increasing and soil moisture might still be adequate.Facultad de Ciencias Agrarias y Forestale

Water stress and temperature effects on germination and early seedling growth of <i>Digitaria eriantha</i>

This study focused on the two major processes critical for plant establishment: Seed germination and seedling survival. We determined the effects of (1) water stress and temperature on the germination, and (2) water stress on early seedling growth of Digitaria eriantha cv ‘Irene’. Seeds harvested in 2007 were used for temperature studies, and those coming from 2006 and 2007 for water stress studies. In 2009, viability decreased by 65.4% from 2006 to 2007. During the first twenty-four hours, germination was more than 50% at constant (30 or 35°C) than alternating (10/30 or 10/35°C) temperatures, although total germination was about 80% for all temperature treatments. Polyethylene glycol 8000 was used to impose water stress conditions. Germination percentages and coefficients of velocity decreased with decreasing water potentials. Early seedling growth was smaller at lower water potentials. D. eriantha cv ‘Irene’ appeared to germinate within a wide range of temperatures, but it varied greatly in germination response to water potentials. Results suggest that this species could be planted in late spring-early summer, when seedbed temperatures are increasing and soil moisture might still be adequate.Facultad de Ciencias Agrarias y Forestale

Central blood pressure and pulse wave velocity: relationship to target organ damage and cardiovascular morbidity-mortality in diabetic patients or metabolic syndrome. An observational prospective study. LOD-DIABETES study protocol

<p>Abstract</p> <p>Background</p> <p>Diabetic patients show an increased prevalence of non-dipping arterial pressure pattern, target organ damage and elevated arterial stiffness. These alterations are associated with increased cardiovascular risk.</p> <p>The objectives of this study are the following: to evaluate the prognostic value of central arterial pressure and pulse wave velocity in relation to the incidence and outcome of target organ damage and the appearance of cardiovascular episodes (cardiovascular mortality, myocardial infarction, chest pain and stroke) in patients with type 2 diabetes mellitus or metabolic syndrome.</p> <p>Methods/Design</p> <p><b>Design</b>: This is an observational prospective study with 5 years duration, of which the first year corresponds to patient inclusion and initial evaluation, and the remaining four years to follow-up.</p> <p><b>Setting</b>: The study will be carried out in the urban primary care setting.</p> <p><b>Study population</b>: Consecutive sampling will be used to include patients diagnosed with type 2 diabetes between 20-80 years of age. A total of 110 patients meeting all the inclusion criteria and none of the exclusion criteria will be included.</p> <p><b>Measurements</b>: Patient age and sex, family and personal history of cardiovascular disease, and cardiovascular risk factors. Height, weight, heart rate and abdominal circumference. Laboratory tests: hemoglobin, lipid profile, creatinine, microalbuminuria, glomerular filtration rate, blood glucose, glycosylated hemoglobin, blood insulin, fibrinogen and high sensitivity C-reactive protein. Clinical and 24-hour ambulatory (home) blood pressure monitoring and self-measured blood pressure. Common carotid artery ultrasound for the determination of mean carotid intima-media thickness. Electrocardiogram for assessing left ventricular hypertrophy. Ankle-brachial index. Retinal vascular study based on funduscopy with non-mydriatic retinography and evaluation of pulse wave morphology and pulse wave velocity using the SphygmoCor system. The medication used for diabetes, arterial hypertension and hyperlipidemia will be registered, together with antiplatelet drugs.</p> <p>Discussion</p> <p>The results of this study will help to know and quantify the prognostic value of central arterial pressure and pulse wave velocity in relation to the evolution of the subclinical target organ damage markers and the possible incidence of cardiovascular events in patients with type 2 diabetes mellitus.</p> <p>Trial Registration</p> <p>ClinicalTrials.gov Identifier: NCT01065155</p