406 research outputs found

    Variability of DOC and nitrate responses to storms in a small Mediterranean forested catchment

    No full text
    International audienceSevere drought periods followed by intense rainfall often leads to major floods in Mediterranean catchments. The resulting hydrology is complex and the response of solutes in the streams is often unpredictable. This study aimed to identify the most relevant factors controlling the hydrological responses to storms of an intermittent Mediterranean stream and to link those factors with dissolved organic carbon (DOC) and nitrate during storm events. Measurements of climate, hydrology, DOC and nitrate concentrations during 26 storm events over three hydrological years were analysed. The contribution of the storm events to the total DOC and nitrate annual export was also calculated. Nitrate was mainly mobilised during high flow, while most of the DOC export occurred during baseflow. Solute concentrations peaked after drought periods and the solute export was maximal during the largest rainfalls (i.e. > 100 L m-2). One single large storm contributed some 22% of the total annual export of DOC, and about 80% of that of nitrate. Discharge was a good predictor of neither DOC nor nitrate responses, so variables other than discharge were considered. Factor Analysis was used to identify the main factors controlling the biogeochemical responses. Antecedent moisture conditions and the magnitude of the storm event were the most relevant factors and accounted for 63% of the total variance. Solute responses during high flow were highly variable. However, solute concentration changes showed a significant and moderate relationship with the factors controlling the hydrological responses (i.e. ? DOC v. the antecedent moisture conditions and ? NO3-N v. the magnitude of the storm event). Keywords: dissolved organic carbon, nitrate, Mediterranean, drought, Fuirosos catchment, storms</p

    Green light: gross primary production influences seasonal stream N export by controlling fine-scale N dynamics

    Get PDF
    Monitoring nutrient concentrations at fine-scale temporal resolution contributes to a better understanding of nutrient cycling in stream ecosystems. However, the mechanisms underlying fine-scale nutrient dynamics and its implications for budget catchment fluxes are still poorly understood. To gain understanding on patterns and controls of fine-scale stream nitrogen (N) 18 dynamics and to assess how they affect hydrological N fluxes, we explored diel variation in stream nitrate (NO3-) concentration along a headwater stream with increasing riparian area and channel width. At the down-stream site, the highest day-night variations occurred in early-spring when stream NO3- concentrations were 13% higher at night than during day time. Such day-night variations were strongly related to daily light inputs (R2=0.74) and gross primary production (GPP) (R2=0.74), and they showed an excellent fit with day-night NO3- variations predicted from GPP (R2=0.85). These results suggest that diel fluctuations in stream NO3- concentration were mainly driven by photoautotrophic N uptake. Terrestrial influences were discarded because no simultaneous diel variations in stream discharge, riparian groundwater level, or riparian solute concentration were observed. In contrast to the down-stream site, no diel variations in NO3- concentration occurred at the up-stream site likely because water temperature was colder (10 vs. 12 ºC) and light availability was lower (4 vs. 9 mol m-2 d-1). Although daily GPP was between 10-100 folds lower than daily respiration, photoautotrophic N uptake contributed to a 10% reduction in spring NO3- loads at the down-stream site. Our study clearly shows that the activity of photoautotrophs can substantially change over time and along the stream continuum in response to key environmental drivers such as light and temperature, and further that its capacity to regulate diel and seasonal N fluxes can be important even in low productivity streams.Financial supported was provided by the Spanish Government through the projects MONTES-Consolider (CSD2008- 00040-MONTES) and MEDFORESTREAM (CGL2011-30590).Peer reviewe

    Teachers’ beliefs on the use of mother tongue in English lessons in a bilingual school

    Get PDF
    El uso de la lengua materna en clases de inglés es un aspecto que implica las creencias de los profesores de lenguaje adquiridas a través de la experiencia en las aulas de clase y además practicadas con los estudiantes en diferentes momentos de la enseñanza y el aprendizaje del inglés. Este estudio se enfoca en analizar las creencias de los profesores acerca del uso de la lengua materna en las clases de inglés y como está es utilizada como herramienta en el proceso de aprendizaje de una lengua extranjera en un colegio bilingüe en Bogotá. La recolección de los datos se llevó a cabo mediante el uso de tres diferentes técnicas: observaciones de clase, entrevistas estructuradas y un cuestionario. Por otro lado, la tabulación de la información recogida fue organizada a través de un cuadro de triangulación donde los fragmentos analizados y las interpretaciones de los investigadores fueron agrupados en diferentes colores de acuerdo a una categoría específica y relaciones

    América Latina y Asia del Este: una mirada al papel de los choques externos

    Get PDF
    El presente estudio plantea una comparación entre el impacto que han tenido los choques externos en la región latinoamericana y en el este asiático, para el periodo comprendido entre 1995 y 2009. Con el fin de evaluar si dicho impacto ha sido diferente en cada región, se plantea la estimación por medio de un modelo VEC y un Panel VEC, que permiten concluir que los choques externos han afectado a América Latina, como era de esperarse, pero en igual medida han afectado a Asia del Este. Dicho resultado plantea una alteración de la hipótesis inicial, que suponía que las economías de Asia del Este eran menos vulnerables ante choques externos que los países pertenecientes a la región latinoamericana. La bondad del presente estudio radica entonces en el hallazgo de los choques que impactan a las dos regiones de manera significativa, surgiendo así un nuevo interrogante a la literatura: ¿ Por qué Asia del Este continuó creciendo más que América Latina pese a que los choques externos también la afectan

    Equipamiento educativo en la Localidad de Mártires

    Get PDF
    A partir del análisis histórico y espacial de la localidad de Mártires se desarrolla un planteamiento urbano, teniendo en cuenta los planes parciales alrededor de la zona. Al desarrollar el planteamiento urbano se desarrolla un equipamiento complementario, siendo este un plantel educativo. El plan parcial de la localidad de Mártires desarrollara el centro más grande de la industria naranja en Latinoamérica. En donde se construirá una sede del SENA, con carreras técnicas y tecnológicas sobre la economía naranja. Por esta razón se plantea el diseño de un plantel educativo con especialidad técnica el cual tendrá carreras relacionadas con la economía naranja.Starting from an spatial and historical analisis in the localidad of Martires, an urban plan is developed, having into account the partial plans near the intervention zone. When the urban plan is done a complementary equipment is design. The partial plan of localidad of Mártires will include the biggest point of orange industry in Latin America. Where a SENA headquarters will be built, with technical and technological careers on the orange economy. For this reason the design of an educational establishment with a technical specialty is proposed, which will have careers related to the orange economy.Arquitecto (a)Pregrad

    Hydrological responses to rainfall events including the extratropical cyclone Gloria in two contrasting Mediterranean headwaters in Spain; the perennial font del Regàs and the intermittent Fuirosos

    Get PDF
    Catchment hydrological responses to precipitation inputs, particularly during exceptionally large storms, are complex and variable, and our understanding of the associated runoff generation processes during those events is limited. Hydrological monitoring of climatically and hydrologically distinct catchments can help to improve this understanding by shedding light on the interplay between antecedent soil moisture conditions, hydrological connectivity, and rainfall event characteristics. This knowledge is urgently needed considering that both the frequency and magnitude of extreme precipitation events are increasing worldwide as a consequence of climate change. In autumn 2018, we installed water level sensors to monitor stream water and near-stream groundwater levels at two Mediterranean forest headwater catchments with contrasting hydrological regimes: Font del Regàs (sub-humid climate, perennial flow regime) and Fuirosos (semi-arid climate, intermittent flow regime). Both catchments are located in northeastern Spain, where the extratropical cyclone Gloria hit in January 2020 and left in ca. 65 h outstanding accumulated rainfalls of 424 mm in Font del Regàs and 230 mm in Fuirosos. During rainfall events of low mean intensity, hydrological responses to precipitation inputs at the semi-arid Fuirosos were more delayed and more variable than at the sub-humid Font del Regàs. We explain these divergences by differences in antecedent soil moisture conditions and associated differences in catchment hydrological connectivity between the two catchments, which in this case are likely driven by differences in local climate rather than by differences in local topography. In contrast, during events of moderate and high mean rainfall intensities, including the storm Gloria, precipitation inputs and hydrological responses correlated similarly in the two catchments. We explain this convergence by rapid development of hydrological connectivity independently of antecedent soil moisture conditions. The data set presented here is unique and contributes to our mechanistic understanding on how streams respond to rainfall events and exceptionally large storms in catchments with contrasting flow regimes

    América Latina y Asia del Este: una mirada al papel de los choques externos

    Get PDF
    El presente estudio plantea una comparación entre el impacto que han tenido los choques externos en la región latinoamericana y en el este asiático, para el periodo comprendido entre 1995 y 2009. Con el fin de evaluar si dicho impacto ha sido diferente en cada región, se plantea la estimación por medio de un modelo VEC y un Panel VEC, que permiten concluir que los choques externos han afectado a América Latina, como era de esperarse, pero en igual medida han afectado a Asia del Este. Dicho resultado plantea una alteración de la hipótesis inicial, que suponía que las economías de Asia del Este eran menos vulnerables ante choques externos que los países pertenecientes a la región latinoamericana. La bondad del presente estudio radica entonces en el hallazgo de los choques que impactan a las dos regiones de manera significativa, surgiendo así un nuevo interrogante a la literatura: ¿ Por qué Asia del Este continuó creciendo más que América Latina pese a que los choques externos también la afectan

    Does breastfeeding prevent atopic dermatitis in newborn?

    Full text link
    Trabajo fin de grado en EnfermeríaINTRODUCCIÓN: La alimentación en el recién nacido juega un papel esencial en la salud y bienestar del mismo, debido al rápido desarrollo y crecimiento que se produce durante el primer año de vida. Desde mitad del siglo XX, se conoce que el mejor método de alimentación para los recién nacidos es la lactancia materna, al garantizar las necesidades nutricionales y metabólicas del lactante durante los 6 primeros meses. Además, la leche humana representa uno de los factores clave en el desarrollo de la microbiota intestinal infantil, a la que se atribuye la iniciación de un poderoso sistema de defensa. Estudios recientes han demostrado que el papel probiótico de las bacterias presentes en la leche materna tiene múltiples efectos beneficiosos en el recién nacido, entre los que destaca su efecto antimicrobiano, inmunomodulador y metabólico. Por último, destacar la existencia de estudios en relación al efecto de la lactancia materna con el desarrollo de dermatitis atópica. OBJETIVO: Evaluar la incidencia de dermatitis atópica en niños alimentados con lactancia materna o de fórmula durante el primer año de vida. METODOLOGÍA: Proyecto de investigación de cohortes prospectivo en niños/as nacidos en el Hospital Universitario La Paz entre el 1 de junio de 2018 y el 31 de mayo de 2019, que hayan sido alimentados exclusivamente con leche materna o de fórmula, durante los seis primeros meses de vida. La recogida de datos la realizarán los profesionales de enfermería con el índice SCORAD que mide la presencia de dermatitis, y los padres con la herramienta PO-SCORAD. Se realizará un análisis descriptivo y bivariante de las variables a través del programa IBM SPSS Statistics 20.0 para Windows. CONCLUSIONES: Los resultados de este estudio serán de utilidad para determinar la importancia de la lactancia materna en el desarrollo de la dermatitis atópicaINTRODUCTION: Nutrition in newborns has a main roll in his health and well-being, due to the quick development and growth that takes place in the first year of life. Since the 50s last century, it is known that the best nutrition method for newborns is breastfeeding as it ensurse nutritional and metabolic needs during the first six months. Furthermore, it is also known that human milk is a key factor for child microbiotic intestinal development and provides the nursing infant with a powerful immune system. Recent studies showed how probiotic bacteria effect has multiple beneficial properties on the newborns, such as antimicrobial, immunomodulatory and metabolic. At last, we shall highlight the existence of multiple studies that show a relation between breastfeeding beneficial effects and development of allergic diseases, for instance, atopic dermatitis. OBJECTIVE: evaluate the impact of atopic dermatitis on breastfeed and formula-feed kids during the first year of life. METHODOLOGY: this project will show a prospective cohort study with kids born between the 1st of June of 2018 and the 31st of May of 2019 at the “Hospital Universitario La Paz”. The kids will exclusively be breastfeed or formula-feed. Data will be gathered by nurses with SCORAD index that measures dermatitis presence and by parents with a sociodemographic questionnaire and PO-SCORAD tool. Descriptive and bivariate analysis of variable will be done with IBM SPSS Statistics 20.0. CONCLUSIONS: results will be useful in stabilizing the relationship between breastfeeding and atopic dermatitis developmen
    corecore