538 research outputs found

    Desarrollo de Materiales para Aplicaciones Marítimas, Fluviales y Militares

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    A platform to design composite materials of a polymeric matrix, that are specifically for military applications on fluvial and naval navigation, has been developed using energy dissipation and storage mechanisms. Our composites are designed to generate synergy between the dissipation capacities of ceramics and high-performance fibers, which are used as the reinforced material in the lightweight laminates. The composite design is combined with processing tools and advanced characterization techniques that result in laminates with reliability, traceability and quality. The platform begins with the identification of energy dissipation mechanisms and the detailed characterization of the polymeric resin. It includes the Time – Temperature – Transformation Diagram (TTT- Diagram) that supplies the optimal processing conditions. Our designs open new paths for military applications including a wide spectrum of protective systems together with geometric versatility, high mechanical resistance and reliabilityUtilizando los múltiples mecanismos de disipación de la energía de impacto a alta velocidad, hemos desarrollado una plataforma de diseño de materiales compuestos de matriz polimérica, especiales para aplicaciones militares en navegación fluvial y marítima.  Nuestros compuestos pretenden hacer sinergia entre las capacidades de disipación de cerámicos y fibras de alto desempeño, los cuales son utilizados como los elementos de refuerzo en los laminados de bajo peso.  El diseño del material es combinado con herramientas de procesamiento y técnicas avanzadas de caracterización que resultan en laminados consistentes de alta repetibilidad, trazabilidad y alta calidad.  La plataforma parte de la identificación de los mecanismos de disipación y de una caracterización detallada de la resina polimérica, el cual incluye un diagrama de Tiempo-Temperatura-Transformación que provee las condiciones óptimas de procesamiento.  Nuestros diseños abren rutas novedosas para aplicaciones militares, los cuales incluyen amplios portafolios de protección, versatilidad geométrica, resistencia mecánica y confiabilida

    Reducing green turtle bycatch in small-scale fisheries using illuminated gillnets: The Cost of Saving a Sea Turtle

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    This is the author accepted manuscript. The final version is available from the publisher via the DOI in this record.Gillnet fisheries exist throughout the oceans and have been implicated in high bycatch rates of sea turtles. In this study, we examined the effectiveness of illuminating nets with light-emitting diodes (LEDs), placed on floatlines in order to reduce sea turtle bycatch in a small-scale bottom-set gillnet fishery. In Sechura Bay, Northern Peru, 114 pairs of control and illuminated nets were deployed. The predicted mean Catch Per Unit of Effort (CPUE) of target species, standardized for environmental variables using generalized additive model analysis, was similar for both control and illuminated nets. In contrast, the predicted mean CPUE of green turtles (Chelonia mydas) was reduced by 63.9% in illuminated nets. One hundred twenty-five green turtles were caught in control nets while 62 were caught in illuminated nets. This statistically significant reduction (GAM analysis, p<0.05) in sea turtle bycatch suggests that net illumination could be an effective conservation tool. Challenges to implementing the use of LEDs include equipment costs, increased net handling times, and limited awareness among fishermen regarding the effectiveness of this technology. Cost estimates for preventing a single sea turtle catch are as low as 34USD,whilethecoststooutfittheentiregillnetfisheryinSechuraBaycanbeaslowas34 USD, while the costs to outfit the entire gillnet fishery in Sechura Bay can be as low as 9200 USD. Understanding these cost challenges emphasizes the need for institutional support from national ministries, international non-governmental organizations and the broader fisheries industry to make possible widespread implementation of net illumination as a sea turtle bycatch reduction strategy.ProDelphinusDarwin InitiativeNational Marine Fisheries Service of the National Oceanic and Atmospheric AdministrationUniversity of Hawaii Joint Institute for Marine and Atmospheric Researc

    Gold(I) Catalysis Applied to the Stereoselective Synthesis of Indeno[2,1-b]thiochromene Derivatives and Seleno Analogues

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    A gold(I)-catalyzed cascade reaction for the stereoselective synthesis of sulfur- or selenium-containing indeno[1,2-b]chromene derivatives from o-(alkynyl)styrenes substituted at the triple bond with a thio- or seleno-aryl group is described. The reaction involves a double cyclization process through a proposed key gold−cyclopropyl carbene intermediate that evolves by the intramolecular addition of an aromatic to the cyclopropane ring, affording polycyclic structures. The enantioselective version was studied using gold(I) complexes bearing chiral ligands.We gratefully acknowledge MICINN (PID2020-115789GBC21), “NextGenerationEU/PRTR” (PDC2021-120825-C21), Junta de Castilla y León, and FEDER (BU049P20) for financial support. The project leading to these results also received funding from the “la Caixa” Foundation, under Agreement LCF/PR/PR18/51130007 (CAIXA-UBU001). C.V. and S.S.-P. thank Junta de Castilla y León (Consejería de Educación) and Fondo Social Europeo for postdoctoral contracts

    Application of Chlorella sp. and Scenedesmus sp. in the bioconversion of urban leachates into industrially relevant metabolites

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    This paper explores the ability of Chlorella sp. and Scenedesmus sp. to convert landfill leachates into usable metabolites. Different concentrations (0.5, 1, 5, and 10% v/v) of leachate coupled with an inorganic carbon source (Na2CO3, and NaHCO3) were tested to improve biomass production, metabolites synthesis, and removal of NO3 and PO4 . The result shows that both strains can effectively grow in media with up to 5% (v/v) leachate, while significantly reducing the concentrations of NO3, and PO4 (80 and 50%, respectively). The addition of NaHCO3 as a carbon source improved the final concentration of biomass, lipids, carbohydrates, and the removal of NO3 and PO4 in both strains

    The relationship of the atlantic diet with cardiovascular risk factors and markers of arterial stiffness in adults without cardiovascular disease

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    Background: Studying the adherence of the population to the Atlantic Diet (AD) could be simplified by an easy and quickly applied dietary index. The aim of this study is to analyse the relationship of an index measuring compliance with recommendations regarding the Atlantic diet and physical activity with cardiovascular disease risk factors, cardiovascular risk factors, obesity indexes and arterial stiffness markers. Methods: We included 791 individuals from the EVIDENT study (lifestyles and arterial ageing), (52.3 ± 12 years, 61.7% women) without cardiovascular disease. Compliance with recommendations on AD was collected through the responses to a food frequency questionnaire, while physical activity was measured by accelerometer. The number of recommendations being met was estimated using a global scale between 0 and 14 points (a higher score representing greater adherence). Blood pressure, plasma lipid and glucose values and obesity rates were measured. Cardiovascular risk was estimated with the Framingham equation. Results: In the overall sample, 184 individuals (23.3%) scored between 0–3 on the 14-point index we created, 308 (38.9%) between 4 and 5 points, and 299 (37.8%) 6 or more points. The results of multivariate analysis yield a common tendency in which the group with an adherence score of at least 6 points shows lower figures for total cholesterol (p = 0.007) and triglycerides (p = 0.002). Similarly, overall cardiovascular risk in this group is the lowest (p < 0.001), as is pulse wave velocity (p = 0.050) and the mean values of the obesity indexes studied (p < 0.05 in all cases). Conclusion: The rate of compliance with the Atlantic diet and physical activity shows that greater adherence to these recommendations is linked to lower cardiovascular risk, lower total cholesterol and triglycerides, lower rates of obesity and lower pulse wave velocity values

    Antibióticos empíricos para la neumonía adquirida en la comunidad en pacientes adultos: Una revisión sistemática y un metaanálisis en red

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    Objetivo: El objetivo principal de este metaanálisis en red es identificar el antibiótico empírico (Em-ATB) con mayor probabilidad de ser el mejor (HPBB) en términos de (1) tasa de curación y (2) tasa de mortalidad en pacientes hospitalizados con neumonía adquirida en la comunidad (NAC) . Método: Criterios de inclusión: (1) pacientes adultos (>16 años) diagnosticados de NAC que requirieron hospitalización; (2) aleatorizados a al menos dos Em-ATB diferentes, (3) que informen de la tasa de curación y (4) que estén escritos en inglés o español. Criterios de exclusión: (1) protocolo de antibióticos ambiguo y (2) publicados exclusivamente en formato resumen o carta. Fuentes de datos: Medline, Embase, Cochrane y revisiones de citas desde el 1 de enero de 2000 hasta el 31 de diciembre de 2018. Riesgo de sesgo: Herramienta de Cochrane. Calidad de la revisión sistemática (RS): A MeaSurement Tool to Assess systematic Reviews-2. Certeza de la evidencia: Grading of Recommendations Assessment, Development and Evaluation. Análisis estadísticos: método frecuentista realizado con la biblioteca 'netmeta', paquete R. Resultados: se incluyeron 27 ensayos controlados aleatorizados (ECA) de las 41.307 citas seleccionadas inicialmente. En cuanto al riesgo de sesgo, más de una cuarta parte de los estudios presentaron riesgo bajo y ningún estudio presentó riesgo alto en todos los dominios. La calidad de la RS es moderada. Para la curación, se construyeron dos redes. Así, dos Em-ATB tienen la HPBB: cetarolina 600 mg (dos veces al día) y piperacilina 2000 mg (dos veces al día). Para la mortalidad, se construyeron tres redes. Así, tres Em-ATB tienen la HPBB: ceftriaxona 2000 mg (una vez al día) más levofloxacino 500 (dos veces al día), ertapenem 1000 mg (dos veces al día) y amikacina 250 mg (dos veces al día) más claritromicina 500 mg (dos veces al día). La certeza de la evidencia para cada resultado es moderada. Conclusiones: Para la tasa de curación, ceftarolina y piperacilina son las opciones con la HPBB. Sin embargo, para la tasa de mortalidad, las opciones son ceftriaxona más levofloxacino, ertapenem y amikacina más claritromicina. Parece necesario realizar un ECA que compare los tratamientos con el HPBB para cada evento (curación o mortalidad) (CRD42017060692).Objective: The main aim of this network meta-analysis is to identify the empiric antibiotic (Em-ATB) with the highest probability of being the best (HPBB) in terms of (1) cure rate and (2) mortality rate in hospitalised patients with community acquired pneumonia (CAP) . Method: Inclusion criteria: (1) adult patients (>16 years old) diagnosed with CAP that required hospitalisation; (2) randomised to at least two different Em-ATBs, (3) that report cure rate and (4) are written in English or Spanish. Exclusion criteria: (1) ambiguous antibiotics protocol and (2) published exclusively in abstract or letter format. Data sources: Medline, Embase, Cochrane and citation reviews from 1 January 2000 to 31 December 2018. Risk of bias: Cochrane's tool. Quality of the systematic review (SR): A MeaSurement Tool to Assess systematic Reviews-2. Certainity of the evidence: Grading of Recommendations Assessment, Development and Evaluation. Statistical analyses: frequentist method performed with the 'netmeta' library, R package. Results: 27 randomised controlled trials (RCTs) from the initial 41 307 screened citations were included. Regarding the risk of bias, more than one quarter of the studies presented low risk and no study presented high risk in all domains. The SR quality is moderate. For cure, two networks were constructed. Thus, two Em-ATBs have the HPBB: cetaroline 600 mg (two times a day) and piperacillin 2000 mg (two times a day). For mortality, three networks were constructed. Thus, three Em-ATBs have the HPBB: ceftriaxone 2000 mg (once a day) plus levofloxacin 500 (two times a day), ertapenem 1000 mg (two times a day) and amikacin 250 mg (two times a day) plus clarithromycin 500 mg (two times a day). The certainity of evidence for each results is moderate. Conclusion: For cure rate, ceftaroline and piperaciline are the options with the HPBB. However, for mortality rate, the options are ceftriaxone plus levofloxacin, ertapenem and amikacin plus clarithromycin. It seems necessary to conduct an RCT that compares treatments with the HPBB for each event (cure or mortality) (CRD42017060692)

    A search for point sources of EeV photons

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    Measurements of air showers made using the hybrid technique developed with the fluorescence and surface detectors of the Pierre Auger Observatory allow a sensitive search for point sources of EeV photons anywhere in the exposed sky. A multivariate analysis reduces the background of hadronic cosmic rays. The search is sensitive to a declination band from -85{\deg} to +20{\deg}, in an energy range from 10^17.3 eV to 10^18.5 eV. No photon point source has been detected. An upper limit on the photon flux has been derived for every direction. The mean value of the energy flux limit that results from this, assuming a photon spectral index of -2, is 0.06 eV cm^-2 s^-1, and no celestial direction exceeds 0.25 eV cm^-2 s^-1. These upper limits constrain scenarios in which EeV cosmic ray protons are emitted by non-transient sources in the Galaxy.Comment: 28 pages, 10 figures, accepted for publication in The Astrophysical Journa

    Operations of and Future Plans for the Pierre Auger Observatory

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    Technical reports on operations and features of the Pierre Auger Observatory, including ongoing and planned enhancements and the status of the future northern hemisphere portion of the Observatory. Contributions to the 31st International Cosmic Ray Conference, Lodz, Poland, July 2009.Comment: Contributions to the 31st ICRC, Lodz, Poland, July 200
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