104 research outputs found
Modelos de erosión de base física: características y utilidades
[Resumen] El desarrollo de los modelos de erosión tiene como objetivo facilitar la predicción de la erosión y diseñar así, las posibles medidas de prevención para evitar la pérdida de suelo. Actualmente, estos modelos de erosión tienden a describir los procesos mediante aproximaciones de tipo físico, y han aumentado su complejidad en el tratamiento de datos. En el presente trabajo se analizan las diferencias y semejanzas de 5 modelos principales de erosión de los últimos 20 años (ANSWERS, CREAMS, KINEROS, EUROSEM y WEPP), y se plantean los posibles errores que involucran estos modelos "avanzados", ya sea por su complejidad, como por su utilización.[Abstract] At present, erosion models are common too1s to cope with erosive processes. These models are aimed to predict erosion, thus helping to design management actions oriented to prevent soil loss. Nowadays, erosion models represent physica1 processes, and their comp1exity increas. Diferences and resemblances between 5 main erosion models developed in the 1ast 20 years (ANSWERS, CREAMS, KINEROS, EUROSEM and WEPP), and it's questioned the possible errors associated with these "advanced" models are discussed
Internal evaluation of a physically-based distributed model using data from a Mediterranean mountain catchment
An evaluation of the performance of a physically-based distributed model of a small Mediterranean mountain catchment is presented. This was carried out using hydrological response data, including measurements of runoff, soil moisture, phreatic surface level and actual evapotranspiration. <i>A-priori</i> model parameterisation was based as far as possible on property data measured in the catchment. Limited model calibration was required to identify an appropriate value for terms controlling water loss to a deeper regional aquifer. The model provided good results for an initial calibration period, when judged in terms of catchment discharge. However, model performance for runoff declined substantially when evaluated against a consecutive, rather drier, period of data. Evaluation against other catchment responses allowed identification of the problems responsible for the observed lack of model robustness in flow simulation. In particular, it was shown that an incorrect parameterisation of the soil water model was preventing adequate representation of drainage from soils during hydrograph recessions. This excess moisture was then being removed via an overestimation of evapotranspiration. It also appeared that the model underestimated canopy interception. The results presented here suggest that model evaluation against catchment scale variables summarising its water balance can be of great use in identifying problems with model parameterisation, even for distributed models. Evaluation using spatially distributed data yielded less useful information on model performance, owing to the relative sparseness of data points, and problems of mismatch of scale between the measurement and the model grid.</p> <p style='line-height: 20px;'><b>Keywords: </b>physically-based distributed model, SHETRAN, parameterisation, Mediterranean mountain catchment, internal evaluation, multi-respons
Nuevos datos cronoestratigráficos de la Fm. Marismas (Bajo Guadalquivir)
La Formación Marismas forma la parte superior del relleno sedimentario del sector SW de la cuenca del Guadalquivir. Los datos previos sobre el sondeo Lebrija, indicaban que la parte más alta de esta formación tenía edades de hasta 9.6 kyr BP y en la parte inferior eran cercanas o fuera del rango del radiocarbono, pero posterior a la reversión
Brunhes-Matuyama. En este trabajo se aportan 17 nuevas dataciones realizadas mediante racemización de aminoácidos en valvas de ostrácodos en este mismo sondeo, con el fin de
completar la cronología y el modelo de edad de la parte superior e inferior de la Fm Marismas. El resultado indica que el tramo situado por debajo del metro 56, arroja edades
que oscilan entre 164685±14110 y 202830±30255, que se correlacionan con los estadios isotópicos marinos MIS 6-7 del Pleistoceno medio, edad sensiblemente más baja a las inferidas para esta formación en otros puntos de la Cuenca del bajo GuadalquivirEste trabajo se ha realizado dentro del proyecto Guadaltyc (Impacto del clima y la tectónica en el registro sedimentario de la Cuenca del Guadalquivir, (CGL2012-30875).Peer Reviewe
Hepatitis A virus in urban sewage from two Mediterranean countries.
Molecular methods for the detection and typing of hepatitis A virus (HAV) strains in sewage were applied to determine its distribution in Cairo and Barcelona. The study revealed the occurrence of different patterns of hepatitis A endemicity in each city. The circulating strains characterized, whether in Cairo or Barcelona, were genotype IB. The effects of a child vaccination programme and the increase in the immigrant population on the overall hepatitis A occurrence in Barcelona were evaluated. While vaccination contributed to a significant decrease in the number of clinical cases, the huge recent immigration flow has probably been responsible for the re-emergence of the disease in the last year of study, in the form of small outbreaks among the non-vaccinated population
Magnetobiochronology of lower Pliocene marine sediments from the lower Guadalquivir Basin: insights into the tectonic evolution of the Strait of Gibraltar area
The Gibraltar Arc is a complex tectonic region, and several competing models have been proposed to explain its evolution. We studied the sedimentary fill of the Guadalquivir Basin to identify tectonic processes that were occurring when the reopening of the Strait of Gibraltar led to the reestablishment of Mediterranean outflow. We present a chronostratigraphic framework for the Lower Pliocene sediments from the lower Guadalquivir Basin (SW Spain). The updated chronology is based on magnetobiostratigraphic data from several boreholes. Our results show that the studied interval in the La Matilla core is in the early Pliocene section, providing better constraints on the sedimentary evolution of the basin during that period. Migrating depositional facies led to a younger onset of sandy deposition basinward. At the northwestern passive margin, a 0.7 m.y. period of sedimentary bypass related to a sharp decrease in sedimentation rates and lower sea levels resulted from the tectonic uplift of the forebulge. In contrast, high sedimentation rates with continuous deep-marine sedimentation are recorded at the basin center due to continuous tectonic subsidence and west-southwestward progradation of axial depositional systems. The marginal forebulge uplift, continuous tectonic basinal subsidence, and southward progradation of clinoforms in the early Pliocene can be explained by the pull of a lithospheric slab beneath the Gibraltar Arc as the Strait of Gibraltar opened. These findings are, to our knowledge, the first reported sedimentary expression of slab pull beneath the Betics related to the opening of the Strait of Gibraltar after the Messinian salinity crisis
Trends in maternal and neonatal mortality in South Africa: a systematic review protocol
Las formaciones Plio-Cuaternarias de El Abalario, en el litoral de la provincia de Huelva
Influence of socioeconomic status on community-acquired pneumonia outcomes in elderly patients requiring hospitalization: a multicenter observational study
The associations between socioeconomic status and community-acquired pneumonia outcomes in adults have been studied although studies did not always document a relationship.
The aim of this multicenter observational study was to determine the association between socioeconomic status and community-acquired pneumonia outcomes in the elderly, in the context of a public health system providing universal free care to the whole population
The impact of the Great Recession on mental health and its inequalities: the case of a Southern European region, 1997–2013
Background: Numerous studies have shown that macroeconomic changes have a great influence on health, prompting different concerns in recent literature about the effects of the current recession. The objetive of the study was to assess the changes in the mental health of the working-age population in the Basque Country (Spain) and its social inequalities following the onset of the 2008 recession, with special focus on the role of unemployment.
Methods: Repeated cross-sectional study on the population aged 16-64, using four Basque Health Surveys (1997-2013). Age-adjusted prevalences of poor mental health and incremental prevalence ratios (working status and social class adjusted) between years were calculated. Absolute/relative measures of social inequalities were also calculated.
Results: From 2008, there was a clear deterioration in the mental health, especially among men. Neither changes in employment status nor social class accounted for these changes. In men, the deterioration affected all working status categories, except the retired but significant changes occurred only among the employed. In women, poor mental health significantly increased among the unemployed. Students were also especially affected. Relative inequalities increased only in men.
Conclusions: The Great Recession is being accompanied by adverse effects on mental health, which cannot be fully explained by the increase of unemployment. Public healtThis work was partially supported by the Ministry of Economy and Competitiveness (State Programme for Promotion of Scientific and Technical Research Challenges (CSO2013-44886-R))
Guadalquivir Basin
Cap. 2.2. Guadalquivir Basin, páginas 40-59.Instituto Geológico y Minero de España, EspañaUniversidad de Salamanca, EspañaUniversitar de Barcelona, EspañaUniversitat Politècnica de Barcelona, EspañaGas Natural Fenosa, EspañaDepartamento de Ciências da Terra, Universidade de Coimbra, PortugalPeer reviewe
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