1,517 research outputs found

    Comparison of Potential Sites in China for Erecting a Hybrid Solar Tower Power Plant with Air Receiver

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    AbstractIn this work transient simulation results of a hybrid solar tower power plant with openvolumetric receiver technology are presented for several locations in China. The openvolumetric receiver uses ambient air as heat transfer fluid and the hybridization can be realized with additional firing. The solar receiver and/or the additional firing heat up the air which is then passed through a boiler of a conventional Rankine cycle. The simulated plantis based on the configuration of the solar thermal test and demonstration power plant located in Jülich (STJ). The investigatedplant operates in hybrid - parallelmode which allows a constant power generation. The meteorological data for the different sites in China was taken from the software Meteonorm in a time resolution of one hour. The solar tower power simulation tool was developed in the simulation environment MATLAB/Simulink

    Seroprevalencia de la toxoplasmosis humana en Córdoba

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    Se realiza un estudio sobre seroprevalencia de la toxoplasmosis humana en Córdoba, mediante inmunofluorescencia indirecta y hemaglutinación indirecta. La muestra encuestada se compone de 443 sueros, 356 personas supuestamente sanas (estudiantes fundamentalmente) y 87, consideradas de “alto riesgo” (enfermos del Hospital “Reina Sofía”). La positividad obtenida para el total de la muestra ha sido del 43,79 % con IFI y 53,50 % para HAI. Con respecto al sexo, la prevalencia es superior en mujeres con un 54,36 % y 70,47 % con IFI y HAI, respectivamente, en varones el 38,43 % y 44,90 % para las mismas pruebas. En relación con la procedencia de la muestra, 31,lB % con IFI y 43,25 % para HAI sobre la población normal, en la de “alto riesgo” para ambas pruebas el 95,40 %. Entre ambas pruebas hay diferencias significativas a títulos bajos, no así en diluciones altas, Concluimos que la toxoplasmosis humana está presente y difundida en las poblaciones estudiadasA seroprevalency study of human toxoplasmosis was carried out in Córdoba, using indirect immunofluorescence and indirect haemoglutination. The sample of people interviewed was made up of 443 serums, 356 supposedly healthy people (mainly students) and 87, considered “high risk” (pafients from the “Reina Sofia” Hospital). The positiveness obtained for the total of the sample was 43,79 % with IFI and 53,59 % for HAI. As regards sex of the person tested, prevalence is higher in women, with 54,36 % and 70,47 % with IFI and HAI respectively, in men the scores were 38,43 % and 44,90 % for the same tests. As far as the origin of the sample was concerned, there were 31,lB % with IFI and 43,25 % for HAI of the nornal population, in the “high risk” sample, for both tests it was 9540 %. With both tests there are significative differences in low amounts, but not in high dilutions. We conclude that human toxoplasmosis is present and widespread in the studied population

    Contribution of commercial fish species to human mercury exposure: an evaluation near the Mid-Atlantic Ridge

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    Fish consumption is frequently associated with the prevention of some human diseases, being simultaneously a major pathway of mercury (Hg) exposure. Therefore, the aim of the study was to evaluate the contribution of 28 commercial fish species to the human Hg exposure in the Azores archipelago (Portuguese region with highest fish consumption per capita). These species potentially contributed on average to 7.47 mg of Hg per capita, although low Hg levels had been detected in fish. Mora moro and Zeus faber exceeded the maximum permitted for fish consumption (> 0.5 μg g−1 ww) even though they were not the species contributing the most to human Hg exposure. On the other hand, Katsuwonus pelamis was the main contributor due to increased fish landings. Furthermore, an increase in Hg content with trophic level has been suggested, as carnivore fish exhibited higher Hg levels than omnivores. In addition, demersal fish generally presented higher Hg concentration (although non-significant) than pelagic ones, possibly related with increased Hg values of their prey at this depth. Notwithstanding, THQ (Target Hazard Quotient) being < 1 for all species indicates that the daily human exposure to Hg via fish consumption is not likely to cause any negative health risks.publishe

    Effects of discontinued endurance methods on VO2max in judokas

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    Este estudio tuvo como objetivo investigar el efecto de dos diferentes planes de entrenamiento de resistencia basados en la metodología discontinua (intermitente e interválica), sobre el VO2Máx de atletas Antioqueños de Judo de rendimiento. Para ello, 21 Judokas de la Selección Antioqueña pertenecientes a la categoría Senior (20,43±4,18 años), fueron distribuidos aleatoriamente en tres grupos, dos grupos experimentales y un grupo control. Ambos grupos experimentales entrenaron la resistencia durante 4 semanas con 4 estímulos por semana, uno de los grupos experimentales basó su entrenamiento en el método interválico y el otro en el intermitente. Por su parte, el grupo control no realizó ningún tipo de entrenamiento de la resistencia. No se hallaron diferencias significativas entre pretest y postest de ninguno de los grupos ni experimentales ni el de grupo control (p>0,05). Se concluyó que el entrenamiento de la resistencia basado en métodos discontinuos no produjo diferencias significativas en el VO2Máx

    QoSatAr: a cross-layer architecture for E2E QoS provisioning over DVB-S2 broadband satellite systems

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    This article presents QoSatAr, a cross-layer architecture developed to provide end-to-end quality of service (QoS) guarantees for Internet protocol (IP) traffic over the Digital Video Broadcasting-Second generation (DVB-S2) satellite systems. The architecture design is based on a cross-layer optimization between the physical layer and the network layer to provide QoS provisioning based on the bandwidth availability present in the DVB-S2 satellite channel. Our design is developed at the satellite-independent layers, being in compliance with the ETSI-BSM-QoS standards. The architecture is set up inside the gateway, it includes a Re-Queuing Mechanism (RQM) to enhance the goodput of the EF and AF traffic classes and an adaptive IP scheduler to guarantee the high-priority traffic classes taking into account the channel conditions affected by rain events. One of the most important aspect of the architecture design is that QoSatAr is able to guarantee the QoS requirements for specific traffic flows considering a single parameter: the bandwidth availability which is set at the physical layer (considering adaptive code and modulation adaptation) and sent to the network layer by means of a cross-layer optimization. The architecture has been evaluated using the NS-2 simulator. In this article, we present evaluation metrics, extensive simulations results and conclusions about the performance of the proposed QoSatAr when it is evaluated over a DVB-S2 satellite scenario. The key results show that the implementation of this architecture enables to keep control of the satellite system load while guaranteeing the QoS levels for the high-priority traffic classes even when bandwidth variations due to rain events are experienced. Moreover, using the RQM mechanism the user’s quality of experience is improved while keeping lower delay and jitter values for the high-priority traffic classes. In particular, the AF goodput is enhanced around 33% over the drop tail scheme (on average)

    AKARI and BLAST Observations of the Cassiopeia A Supernova Remnant and Surrounding Interstellar Medium

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    We use new large area far infrared maps ranging from 65 - 500 microns obtained with the AKARI and the Balloon-borne Large Aperture Submillimeter Telescope (BLAST) missions to characterize the dust emission toward the Cassiopeia A supernova remnant (SNR). Using the AKARI high resolution data we find a new "tepid" dust grain population at a temperature of ~35K and with an estimated mass of 0.06 solar masses. This component is confined to the central area of the SNR and may represent newly-formed dust in the unshocked supernova ejecta. While the mass of tepid dust that we measure is insufficient by itself to account for the dust observed at high redshift, it does constitute an additional dust population to contribute to those previously reported. We fit our maps at 65, 90, 140, 250, 350, and 500 microns to obtain maps of the column density and temperature of "cold" dust (near 16 K) distributed throughout the region. The large column density of cold dust associated with clouds seen in molecular emission extends continuously from the surrounding interstellar medium to project on the SNR, where the foreground component of the clouds is also detectable through optical, X-ray, and molecular extinction. At the resolution available here, there is no morphological signature to isolate any cold dust associated only with the SNR from this confusing interstellar emission. Our fit also recovers the previously detected "hot" dust in the remnant, with characteristic temperature 100 K.Comment: Accepted for publication in the Astrophysical Journal. Maps and related data are available at http://blastexperiment.info

    Efectos de los métodos discontinuos de resistencia sobre VO2 máx de judokas

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    The aim of this study was to investigate the effect of two different endurance training protocols based on discontinuous methodology (intermittent and interval), on the VO2Peakof Antioquia's top Judo athletes. To do this, 21 judokas of Antioquia’s judo team, belonging to the category of Major (20.43±4.18 years) were randomized into two experimental groups and a control group. Both experimental groups were trained in endurance for 4 weeks with 4 weekly stimuli, one of the experimental groups was trained based on the interval training method, and the other was trained based on the intermittent method. Meanwhile, the control group made no endurance training.No significant differences between pretest and posttest of both experimental groups, (intermittent and interval training protocols), nor in the control group were found (p&gt; 0.05). It was concluded that the endurance training protocols based on discontinuous methodology, produced no significant difference in VO2Peakof Antioquia's top Judo athletes.Este estudio tuvo como objetivo investigar el efecto de dos diferentes planes de entrenamiento de resistencia basados en la metodología discontinua (intermitente e interválica), sobre el VO2Máx de atletas Antioqueños de Judo de rendimiento.Para ello, 21 Judokas de la Selección Antioqueña pertenecientes a la categoría Senior (20,43±4,18 años), fueron distribuidos aleatoriamente en tres grupos, dos grupos experimentales y un grupo control. Ambos grupos experimentales entrenaron la resistencia durante 4 semanas con 4 estímulos por semana, uno de los grupos experimentales basó su entrenamiento en el método interválico y el otro en el intermitente. Por su parte, el grupo control no realizó ningún tipo de entrenamiento de la resistencia.             No se hallaron diferencias significativas entre pretest y postest de ninguno de los grupos ni experimentales ni el de grupo control (p&gt;0,05). Se concluyó que el entrenamiento de la resistencia basado en métodos discontinuos no produjo diferencias significativas en el VO2Máx.

    Mesoscopic Modeling of the Encapsulation of Capsaicin by Lecithin/Chitosan Liposomal Nanoparticles

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    The transport of hydrophobic drugs in the human body exhibits complications due to the low solubility of these compounds. With the purpose of enhancing the bioavailability and biodistribution of such drugs, recent studies have reported the use of amphiphilic molecules, such as phospholipids, for the synthesis of nanoparticles or nanocapsules. Given that phospholipids can self-assemble in liposomes or micellar structures, they are ideal candidates to function as vehicles of hydrophobic molecules. In this work, we report mesoscopic simulations of nanoliposomes, constituted by lecithin and coated with a shell of chitosan. The stability of such structures and the efficiency of the encapsulation of capsaicin, as well as the internal and superficial distribution of capsaicin and chitosan inside the nanoliposome, were analyzed. The characterization of the system was carried out through density maps and the potentials of mean force for the lecithin-capsaicin, lecithin-chitosan, and capsaicin-chitosan interactions. The results of these simulations show that chitosan is deposited on the surface of the nanoliposome, as has been reported in some experimental works. It was also observed that a nanoliposome of approximately 18 nm in diameter is stable during the simulation. The deposition behavior was found to be influenced by a pattern of N-acetylation of chitosan

    Brief communication Social and clinical predictors of drug-resistant tuberculosis in a public hospital, Monterrey, Mexico

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    a b s t r a c t Purpose: Drug-resistant tuberculosis (DRTB) is steadily increasing in Mexico, but little is known of patient risk factors in the MexicoeUnited States border region. This preliminary case-control study included 95 patients with active pulmonary TB with drug susceptibility results attending the José E. González University Hospital in the urban hub of Nuevo Leóndthe Monterrey Metropolitan Area. We report potential social and clinical risk factors of DRTB among this hospital-based sample. Methods: We collected data through face-to-face interviews and medical record reviews from 25 cases with DRTB and 70 drug-sensitive controls. DNA was collected to assess an effect of genetic ancestry on DRTB by using a panel of 291,917 genomic markers. We calculated crude and multivariate logistic regression. Results: After adjusting for potential confounding factors, we found that prior TB treatment (odds ratio, 4.5; 95% confidence interval, 0.9e21.1) and use of crack cocaine (odds ratio, 4.6; 95% confidence interval, 1.1e18.7) were associated with DRTB. No other variables, including genetic ancestry and comorbidities, were predictive. Conclusions: Health care providers may benefit from recognizing predictors of DRTB in regions where routine drug susceptibility testing is limited. Prior TB treatment and illicit drug use, specifically crack cocaine, may be important risk factors for DRTB in this region
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