10,353 research outputs found

    Influence of the Yesa reservoir on floods of the Aragón River, central Spanish Pyrenees

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    International audienceThe Yesa reservoir, the largest Pyrenean reservoir, was constructed in 1959 to supply water to new irrigated areas in the Ebro Depression, NE Spain. It is filled from October to May-June and then releases large quantities of water in the summer via the Bardenas Canal. The results confirm that the frequency of floods downstream of the dam decreased. The reduction mainly depends on two factors: i) the water storage level, and ii) the season of the year. Floods are very well controlled when the reservoir level is lower than 50%. Between 50 and 70%, only the highest floods are controlled. Finally, the reservoir retains mainly autumn and spring floods; most winter floods are released downstream to ensure the safety of the dam. Keywords: reservoir, flood control, flood seasonality, flood frequency, river regime, Pyrenees</p

    Anticoncepción poscoital. Características de la demanda

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    ObjetivoConocer el perfil de las mujeres que demandan anticoncepción poscoital (APC).DiseñoDescriptivo transversal. Emplazamiento. Centro de Orientación Familiar (COF), Área 4 del Instituto Madrileño de Salud. Madrid.ParticipantesTodas las mujeres que acudieron en el año 2000 para requerir APC (n = 404).MedicionesSe realizó una encuesta con variables sociodemográficas relacionadas con la APC y con la vida sexual.ResultadosLa edad media fue de 23,9 años (límites, 14–49); el 9,9% era menor de edad. La media de coitos al mes era de 6,7, el número de años de relaciones sexuales era de 4,9 y el primer coito se produjo, de media, a los 18 años. El 90,9% afirmaba tener pareja estable. Tenía estudios secundarios o universitarios un 75%. El 55,7% manifestaba no haber recibido información sobre anticonceptivos. El 19,5% utilizó APC en otra ocasión. El 6,5% había tenido alguna interrupción voluntaria de embarazo y de éstas, el 36% había utilizado APC anteriormente. Los motivos de consulta fueron: rotura de preservativo (69,3%), preservativo retenido (16,9%) y coito sin protección (12%). El 7% tuvo otros coitos de riesgo en el mismo ciclo. Un 33,2% las remitía su equipo de atención primaria, acudió por conocidos el 19% y desde servicios de urgencias el 16%. Conocía el COF un 26,1%. En el 12,2% no se prescribió APC por mínimo riesgo de embarazo. Realizaron la valoración una enfermera (52,6%), médicos residentes (34,4%) y una ginecóloga (13%).ConclusionesFalta información sobre métodos anticonceptivos. La mayoría de las pacientes son derivadas por otros servicios sanitarios.ObjectiveDefine the profile of the women that ask for emergency contraception (EC).DesignTransversal descriptive investigation.SettingFamiliar Planning Center of 4th Area of Instituto Madrileño de Salud. in Madrid. Participants. All the women that went in the year 2000 requiring EC (n=404).MeasurementsWas carried out a survey with sociodemographic variables, related with the EC and with the sexual life.ResultsThe average age was of 23.9 years (age range 14 to 49) were inquired, 9.9 were under 18. They had an average of 6.7 intercourses per month, the first intercourse when they were 18 years old on average, and 4.9 years of sexual relationships. 90.9% stated to have a couple. 75% were graduated from high school or university, and 55.7% said they had never received information about contraceptives. For 19.5% this was not the first time they asked for EC. 6.5% had interrupted on purpose pregnancy and 36% of them had used EC before. The reasons to demand EC were: condom break (69.3%), held condom (16.9%) and intercourse without any protection (12%). 7% acknowledged other risky intercourses during the same period. 33.2% had been sent by a General Practitioner, 26.1% knew the center, 19% were sent by acquaintances and 16% from Emergency Services. EC was not prescribed in 12.2% of the cases because of minimum risk to pregnancy. The evaluation was made by a nurse (52.6%), by a doctor (34.4%) and by a gynecologist (13%).ConclusionsThere is a lack of information about contraceptive methods. Most of the patients are sent from other sanitary services

    Transversal inhomogeneities in dilute vibrofluidized granular fluids

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    The spontaneous symmetry breaking taking place in the direction perpendicular to the energy flux in a dilute vibrofluidized granular system is investigated, using both a hydrodynamic description and simulation methods. The latter include molecular dynamics and direct Monte Carlo simulation of the Boltzmann equation. A marginal stability analysis of the hydrodynamic equations, carried out in the WKB approximation, is shown to be in good agreement with the simulation results. The shape of the hydrodynamic profiles beyond the bifurcation is discussed

    Academic competence, teacher–student relationship, and violence and victimisation in adolescents: The classroom climate as a mediator

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    School violence is a serious social and public health problem prevalent worldwide. Alt-hough the relevance of teacher and classroom factors is well established in the literature, few studies have focused on the role of teacher perceptions in school violence and victimisation and the poten-tial mediational role of classroom climate in this relationship. A total of 2399 adolescents (50% girls), aged between 11 and 18 years (M = 14.65, SD = 1.78) and enrolled in five Spanish Secondary Com-pulsory Education schools completed measures of classroom climate, school violence towards peers and perception of peer victimisation, and their teachers informed about their academic competence and the teacher–student relationship. Correlational analyses revealed that whereas academic competence perceived by the teacher was negatively related to overt violence and victimisation, its relationship with pure relational violence was positive. Structural equation modelling analyses showed that variables of classroom climate (involvement, affiliation, and teacher support) perceived by the students functioned as partial mediators between teacher perceptions of academic competence and of teacher–student relationship and violence and victimisation. In the mediational model, teacher perception of academic competence acted as a direct protective factor against violence and victimisation, and teacher perception of teacher–student relationship acted as a direct risk for violence, as well as an indirect protective factor through classroom climate for victimisation. The interpretation of these results points to the importance of the teacher’s subjective perceptions in the prevention of violence and victimisation problems and their practical implications for the classroom climate perceived by students

    Piezochromic properties of a D-A-D platform: A joint experimental and theoretical perspective

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    Organic π-conjugated molecules with mechanochromic luminescence properties have attracted great interest in the last two decades due to their numerous applications in the optoelectronic field, such as sensors, probes and security inks. Materials that modify their colour under pressure are known as piezochromic materials. Usually, this variation is provoked by changes in the molecular structure, for example, crystal-to-amorphous phase transitions, modifications in dihedral angles or bond distances, and intermolecular interactions. The molecule proposed in this study is a TADF (Thermally activated delayed fluorescence) U-shaped molecule composed by two donors and one acceptor (D-A-D) units with a π-conjugated skeleton [1]. It was synthetized as a powder which under different crystallization methods gives rise to different conformers varying the dihedral angle of the bond that links the D and A units. The donors are two phenothiazine units and the acceptor is a dibenzo[a,j]phenazine unit located in the central core. Two different conformers have been analysed: the quasi equatorial - quasi equatorial (denoted as 1R) and the quasi axial - quasi axial (denoted as 1Y). In this project, we study the configurational changes triggering the piezochromic effects combining density functional theory (DFT) calculations with Raman spectroscopy experiments of the 1R and 1Y conformers during heating or in compression via a sapphire anvil cell [2]. Both show pressure and temperature dependence properties. Besides, these changes are reversible meaning that when the stimuli stop they revert to its original conformation. When these molecules are exposed to different ambient (like pressure or temperature variations) they evolved to a third conformer with an intermediate dihedral angle that results in different Raman, emission and absorption behaviour.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Carbon use efficiency variability from MODIS data

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    [EN] Carbon use efficiency (CUE) describes how efficiently plants incorporate the carbon fixed during photosynthesis into biomass gain and can be calculated as the ratio between net primary production (NPP) and gross primary production (GPP). In this work, annual CUE has been obtained from annual GPP and NPP MODIS products for the peninsular Spain study area throughout eight years. CUE is spatially and temporally analyzed in terms of the vegetation type and annual precipitation and annual average air temperature. Results show that dense vegetation areas with moderate to high levels of precipitation present lower CUE values, whereas more arid areas present the highest CUE values. However, the temperature effect on the spatial variation of CUE is not well characterized. On the other hand, inter-annual variations of CUE of different ecosystems are discussed in terms of inter-annual variations of temperature and precipitation. It is shown that CUE exhibited a positive correlation with precipitation and a negative correlation with temperature in most ecosystems. Thus, CUE decreases when the ecosystem conditions change towards aridity.[ES] La eficiencia en el uso de carbono (CUE) cuantifica el incremento de la biomasa de las plantas a partir del carbono que fijan a través de su actividad fotosintética. En este trabajo se analiza la variación de la CUE anual (estimada a partir del cociente entre los productos de producción primaria neta, NPP, y producción primaria bruta, GPP, anuales de MODIS) en función del tipo de vegetación y de las variables meteorológicas temperatura del aire y precipitación, a lo largo de ocho años en la España peninsular. Los valores más bajos de CUE se encuentran en zonas de vegetación densa con niveles de precipitación de moderada a elevada (superior a 1000 mm/año), mientras que los valores más altos se localizan en zonas más áridas (con precipitación por debajo de 800 mm/año). La influencia de la temperatura es menos marcada. Cuando se analizan las variaciones interanuales de la CUE se observa que, para la mayor parte de los ecosistemas, un incremento de la precipitación produce un incremento de su CUE, mientras que un incremento de la temperatura la disminuye. En este caso, además, la influencia de la temperatura es más significativa desde un punto de vista estadístico. Es decir, para un ecosistema en particular, la CUE disminuye cuando se intensifi-can las condiciones de aridez.Este trabajo ha sido subvencionado, en parte, por los proyectos ERMES (FP7/2007-2013) y ESCENARIOS (MINECO/FEDER, CGL2016-75239-R). Agradecemos a AEMet, y muy especialmente al Dr. J. Tamayo, la cesión de los datos meteorológicos. Los productos MODIS se descargaron utilizando la herramienta online Data Pool, que es cortesía de NASA EOSDIS Land Processes Distributed Active Archive Center (LP DAAC), USGS/Earth Resources Observation and Science (EROS) Center, Sioux Falls, South Dakota, [https://lpdaac.usgs.gov/data_access]. Finalmente, les damos las gracias a los revisores, cuyas sugerencias han contribuido a mejorar el manuscrito.Cañizares, M.; Moreno, A.; Sánchez-Ruiz, S.; Gilabert, M. (2017). Variabilidad de la eficiencia en el uso del carbono a partir de datos MODIS. Revista de Teledetección. (48):1-12. https://doi.org/10.4995/raet.2017.70441124

    A review of current management of vitreomacular traction and macular hole

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    The paper presents a review of the sequence of events of posterior vitreous detachment (PVD), vitreomacular adhesion (VMA), vitreomacular traction (VMT), and macular hole (MH) from their pathophysiological aspects, clinical features, diagnostic implications, and current management strategies. A treatment algorithm to be used in clinical practice in patients with VMA, VMT, and MH based on the presence of symptoms, visual acuity, associated epiretinal membrane, and width of the vitreous attachment is presented. Observation, pharmacologic vitreolysis with ocriplasmin, and surgical treatment are positioned as treatment options in the different steps of the therapeutic algorithm, with clear indications of the paths to be followed according to the initial presenting manifestations and the patient's clinical course
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