372 research outputs found

    The impact of significant input of fine sediment on benthic fauna at tributary junctions: a case study of the Bermejo-Paraguay River confluence, Argentina

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    This study examines the morphological features, suspended sediment inputs and hydraulic conditions within a large river in association with ecological patterns before and after a tributary confluence. In order to examine these effects, the macroinvertebrate distributions from three reaches of the Paraguay and Bermejo Rivers (Paraguay-Argentina) are investigated. The Bermejo River is a tributary that supplies significant quantities of fine sediment to the Paraguay River, primarily in suspension. Two reaches were examined on the Paraguay River, upstream and downstream of the Bermejo River junction, with the third study reach located on the Bermejo River, upstream of the confluence with the Paraguay River. The results provide clear evidence that a significantly increased loading of fine sediment at a river confluence has effects on the distribution and potential movement of benthic invertebrates in the lotic environment by representing physical barriers at affected sites. These effects may be important at both local and regional scales, and such increases in suspended sediment (especially associated with anthropogenic change) may thus pose a major threat to ecosystem integrity that has been historically underestimated

    EFECTO DE LA APLICACIÓN DE NITRÓGENO Y DE ESTIÉRCOL BOVINO SOBRE LA TASA DE CRECIMIENTO EN ALTURA DE PLANTA DEL NARANJO AGRIO (Cilrlls allranlillm L.) DE SEGUNDO AÑO DE IMPLANTACIÓN

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      El aceite esencial petit grain, es obtenido por el proceso de destilación a vapor de hojas y ramacetes de naranjo agrio el cual es cultivado principalmente en la Región Oriental y se constituye en un rubro de importancia para los pequeños productores. Con el objetivo de estudiar el efecto del estiércol bovino y del nitrógeno sobre la tasa de crecimiento del naranjo de segundo año de implantación, fue implantado entre julio-noviembre de 2006, un experimento factorial 4 x 4 en bloques al azar con 3 repeticiones, evaluándose la tasa de crecimiento en altura de planta durante 60 días. Las dosis de estiércol bovino y de nitrógeno aplicadas no influyen en la tasa de crecimiento del naranjo agrio en los 60 días después de la aplicación.   &nbsp

    Reversible cardiomyopathy in a patient with Marfan’s syndrome. Case report

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    Marfan´s syndrome is a multisystemic, autosomal dominant congenital abnormality of variable penetrance that affects the integrity of connective tissue. In the cardiovascular system, the dysfunction of the physiology of the aortic root and the myocardial fibrosis originates non-ischemic cardiomyopathy independent of valve lesions. Few data have been reported on the prevalence of arrhythmias and its impact on heart function. We present a 21-year-old man with Marfan’s syndrome and heart failure with frequent supraventricular arrhythmias and aortic root dilation. After ablation in the posteroseptal area of the mitral ring and Tirone David Surgery, there was clinical improvement, the left ventricular ejection fraction increased dramatically from 33% to 46%, the left ventricular end-diastolic volume decreased from 90 ml/m2 to 77 ml/m2 and the NT-proBNP decrease from 1100 pg/mL at 180 pg/mL.Marfan´s syndrome is a multisystemic, autosomal dominant congenital abnormality of variable penetrance that affects the integrity of connective tissue. In the cardiovascular system, the dysfunction of the physiology of the aortic root and the myocardial fibrosis originates non-ischemic cardiomyopathy independent of valve lesions. Few data have been reported on the prevalence of arrhythmias and its impact on heart function. We present a 21-year-old man with Marfan’s syndrome and heart failure with frequent supraventricular arrhythmias and aortic root dilation. After ablation in the posteroseptal area of the mitral ring and Tirone David Surgery, there was clinical improvement, the left ventricular ejection fraction increased dramatically from 33% to 46%, the left ventricular end-diastolic volume decreased from 90 ml/m2 to 77 ml/m2 and the NT-proBNP decrease from 1100 pg/mL at 180 pg/mL

    Modelling of photonic wire Bragg Gratings

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    Some important properties of photonic wire Bragg grating structures have been investigate. The design, obtained as a generalisation of the full-width gap grating, has been modelled using 3D finite-difference time-domain simulations. Different types of stop-band have been observed. The impact of the grating geometry on the lowest order (longest wavelength) stop-band has been investigated - and has identified deeply indented configurations where reduction of the stop-bandwidth and of the reflectivity occurred. Our computational results have been substantially validated by an experimental demonstration of the fundamental stop-band of photonic wire Bragg gratings fabricated on silicon-on-insulator material. The accuracy of two distinct 2D computational models based on the effective index method has also been studied - because of their inherently much greater rapidity and consequent utility for approximate initial designs. A 2D plan-view model has been found to reproduce a large part of the essential features of the spectral response of full 3D models

    Energy balance in a mango orchard in Northeast of Brazil.

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    The main objective of this research was the determination of the energy balance in a mango orchard

    Coeficiente de cultura e produtividade da mangueira irrigada.

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    Data of solar radiation, soil heat flux and dry and wet bulbs air temperature were used in the elaboration of theabove canopy energy balance based on Bowen ratio. Also, data soil humidity profiles were used in thedetermination of the soil water balance of a dripping irrigated seven years old mango orchard, cv. ?Tommy Atkins’.The field experiment was conducted in the irrigated perimeter of Bebedouro, in Petrolina-PE, Brazil (Latitude:09009`S, Longitude: 40022`W; altitude: 365.5m), in the years of 1998 and 1999. The obtained results indicatedthat, in the submedian San Francisco river region soil and climate conditions, the mango orchard waterconsumption, represented by the corp coefficient (Kc), doesn't stay constant throughout the productive cycle, but itvaries as a function of the days after flowering(DAF) according to the following equation: Kc = 0.36 + 0.009(DAF) – 4.0 x 10-5 (DAF)2, with r2 = 0.79

    Componentes do balanco de energia em pomar irrigado no Nordeste.

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    Results of an energy balance based on the Bowen ratio method are presented. Two field experiments were carriedout in 1998 and 1999, with a mango orchard in Petrolina, PE. The mango trees were irrigated by a drip irrigationsystem. A micrometeorology tower was set up for installation of the instruments used for the energy balance,which are: net radiation, two psychrometers and two anemometers installed in two levels above the canopy of theculture, and more two radiometers (global solar radiation and the radiation reflected by the culture). Two plates formeasuring the soil heat flux in a depth of 5 cm were installed. The analog signals of all instruments were scannedonce every five seconds and averaged every 10 minutes using a micrologger. It was verified that didn't happengreat differences among the components of the energy balance in relation to the two experiments. In general, thelatent heat flux was of the order of 80% of Rn, while H and G represented around 15% and 5% of Rn, respectively.Such relationships were analyzed in different phenological phases, as well as the seasonal behavior of the energybalance component

    Cultural effects on neurodevelopmental testing in children from six European countries: An analysis of NUTRIMENTHE Global Database

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    Cultural background is an important variable influencing neuropsychological performance. Multinational projects usually involve gathering data from participants from different countries and/or different cultures. Little is known about the influence of culture on neuropsychological testing results in children and especially in European children. The objectives of this study were to compare neuropsychological performance of children from six European countries (Belgium, Germany, Italy, The Netherlands, Poland and Spain) using a comprehensive neuropsychological battery and to apply a statistical procedure to reduce the influence of country/cultural differences in neuropsychological performance. As expected, the results demonstrated differences in neuropsychological performance among children of the six countries involved. Cultural differences remained after adjusting for other confounders related to neuropsychological execution, such as sex, type of delivery, maternal age, gestational age and maternal educational level. Differences between countries disappeared and influence of culture was considerably reduced when standardised scores by country and sex were used. These results highlight the need for developing specific procedures to compare neuropsychological performance among children from different cultures to be used in multicentre studies

    Perfil de resistencia de Staphylococcus spp aislados de hemocultivos en el Hospital Central del Instituto de Previsión Social

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    Las infecciones nosocomiales por Staphylococcus spp constituyen uno de los problemas de mayor preocupación en salud pública en todo el mundo. Debido a que existen diferencias según centro hospitalario, paciente, área y tiempo de internación es esencial conocer el perfil de resistencia a los antibióticos más utilizados de las cepas de Staphylococcus involucradas en estas infecciones. El objetivo del presente estudio fue determinar el perfil de resistencia de los aislados de Staphylococcus aureus (Sau) y Estafilococo coagulasa negativo (ECN) de muestras de hemocultivos de pacientes adultos, pediátricos y recién nacidos internados entre el 1 de junio de 2005 al 30 de junio de2006, en varios servicios del Hospital Central del Instituto de Previsión Social (IPS.).Se realizó un análisis retrospectivo de los resultados de antibiograma realizados en el Servicio de Microbiología del IPS. Los antibióticos evaluados fueron oxacilina (OXA),penicilina (PEN), eritromicina (ERY), clindamicina (CLI), ciprofloxacina (CIP), gentamicina (GEN), trimetoprim-sulfametoxazol (TMS), tetraciclina (TET) y vancomicina (VAN). De 5698 hemocultivos realizados en este periodo, 1706 (30%) fueron positivos. De estos, en755 (44%) se aisló Staphylococcus spp; correspondiendo 327 (43,3%) a Sau y 428 (56,7%) a ECN. El perfil de resistencia para Sau y ECN fue respectivamente como sigue: OXA 64% y 87%, PEN 96% y 95%, ERY 48% y 52%, CIP 42% y 40%, GEN 48% y 48% yno presentaron R a VAN. El 58% de los Sau y el 56% de los ECN fueron resistentes a más de 4 antibióticos. La alta frecuencia de resistencia a la meticilina y la poliresistencia hallada en este trabajo deben ser tenidos en cuenta a la hora de indicar esquemas deantibióticos empíricos y para realizar ajustes oportunos de los ya iniciados. No se encontró ninguna cepa resistente a la vancomicina, que es considerada el mejor antimicrobiano disponible para el tratamiento de infecciones por estafilococos resistentesa las penicilinas que no son inhibidas por las penicilinasas

    Alguns aspectos fisiologicos da mangueira em condicoes irrigada e de estresse hidrico.

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    Este estudo analisou medidas porométricas feitas em um pomar de manga, variedade Tommy Atkins, plantado em Fevereiro de 1993, e irrigado por gotejamento no campo experimental da Embrapa Semi-Árido em Petrolina, PE, Brasil (Latitude: 090 09`S, Longitude: 400 22`W; altitude: 365,5m), usando um porômetro de difusão, LI - 1600 (Licor, EUA)
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