2,958 research outputs found

    X-ray follow-ups of XSSJ12270-4859: a low-mass X-ray binary with gamma ray FERMI-LAT association

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    XSSJ1227.0-4859 is a peculiar, hard X-ray source recently positionally associated to the Fermi-LAT source 1FGLJ1227.9-4852/2FGLJ1227.7-4853. Multi-wavelength observations have added information on this source, indicating a low-luminosity low-mass X-ray binary (LMXB), but its nature is still unclear. To progress in our understanding, we present new X-ray data from a monitoring campaign performed in 2011 with the XMM-Newton, RXTE, and Swift satellites and combine them with new gamma-ray data from the Fermi and AGILE satellites. We complement the study with simultaneous near-UV photometry from XMM-Newton and with previous UV/optical and near-IR data. The X-ray history of XSSJ1227.0-4859 over 7yr shows a persistent and rather stable low-luminosity (~6x10^33 d_{1\,kpc}^2 erg/s) source, with flares and dips being peculiar and permanent characteristics. The associated Fermi-LAT source 2FGLJ1227.7-4853 is also stable over an overlapping period of 4.7\,yr. Searches for X-ray fast pulsations down to msec give upper limits to pulse fractional amplitudes of 15-25% that do not rule out a fast spinning pulsar. The combined UV/optical/near-IR spectrum reveals a hot component at ~13\,kK and a cool one at ~4.6\,kK. The latter would suggest a late-type K2-K5 companion star, a distance range of1.4--3.6kpc and an orbital period of 7--9 h. A near-UV variability (>6\,h) also suggests a longer orbital period than previously estimated. The analysis shows that the X-ray and UV/optical/near-IR emissions are more compatible with an accretion-powered compact object than with a rotational powered pulsar. The X-ray to UV bolometric luminosity ratio could be consistent with a binary hosting a neutron star, but the uncertainties in the radio data may also allow an LMXB black hole with a compact jet. In this case it would be the first associated with a high-energy gamma-ray source.Comment: 17 pages, 14 figures, 1 table; Accepted for publication in Astronomy & Astrophysics Main Journa

    Suplemento alimenticio en colonias de abejas para la mejora del servicio de polinización de kiwi (Actinidia deliciosa Liang & Ferguson) (Actinidiaceae: Theales)

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    El modelo actual de agricultura determina una disminución en los hábitats seminaturales lo que conduce a una mala nutrición de las colonias de abejas, las cuales generalmente necesitan ser suplementadas con alimentos. Las abejas se utilizan para transferir polen entre plantas de kiwi (Actinidia deliciosa Liang & Ferguson masculina y femenina, aumentando así la calidad de la fruta y el rendimiento de los cultivos. El objetivo principal fue determinar el efecto de la estimulación de las colonias de Apis mellifera L. con suministros alimentarios estándar sobre la recolección de polen de kiwi. Los tratamientos (n= 5 colmenas cada uno) se realizaron en un huerto de kiwis en Mar del Plata, Argentina: Grupo J/A: suministrado con jarabe de azúcar (2:1) + suplemento proteico líquido (“Apipromotor®”); Grupo J/P: suministrado con jarabe de azúcar (2:1) + suplemento de proteínas sólidas ("patty"); Grupo J: suministrado con jarabe de azúcar (2:1); Grupo C: control, no suministrado. Las colonias abastecidas con J, J/P y J/A recolectaron más polen de kiwifruit que el tratamiento control, incluso bajo la presencia de otras especies florales en áreas cercanas. Aunque las abejas recolectaron la mayor parte del polen de otras especies de plantas de hábitats seminaturales, los tratamientos bajo estimulación artificial (J/P, J/A y J) pueden mejorar significativamente el servicio de polinización de kiwis que realizan las abejas.The current agriculture model determines a decrease in semi-natural habitats leading to poor nutrition for honeybee colonies, which usually need to be food supplemented. Honeybees are used to transfer pollen between male and female kiwifruit (Actinidia deliciosaLiang & Ferguson) plants, increasing fruit quality and crop yield. Our main goal was to determine the effect of stimulating Apis mellifera L. colonies with standard food supplies on the collection of kiwifruit pollen. However, honey bees can also forage other flowering species in the crop site´s surrounding areas. We selected kiwifruit as a model to analyze the effects of food supply on pollen collection of the target crop. The following experimental treatments (n = 5 hives each were conducted in a kiwifruit orchard in Mar del Plata, Argentina: Group J/A: supplied with sugar syrup (2:1 + liquid protein supplements ("Apipromotor ®"; Group J/P: supplied with sugar syrup (2:1 + solid protein supplements ("patty";Group J: supplied with sugar syrup (2:1; Group C: control, not supplied. Colonies supplied with J, J/P and J/A collected more kiwifruit pollen than the other two treatments, even under other flowering species in areas nearby. Although honeybees collected most pollen from other plant species of semi-natural habitats, J/P, J, and J/A treatments can significantly improve the honeybees´ kiwifruit pollination service.Fil: de Piano, Fiorella Giselle. Universidad Nacional de Mar del Plata. Instituto de Investigaciones En Produccion, Sanidad y Ambiente. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mar del Plata. Instituto de Investigaciones En Produccion, Sanidad y Ambiente.; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Meroi Arcerito, Facundo René. Universidad Nacional de Mar del Plata. Instituto de Investigaciones En Produccion, Sanidad y Ambiente. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mar del Plata. Instituto de Investigaciones En Produccion, Sanidad y Ambiente.; Argentina. Ministerio de Ciencia. Tecnología e Innovación Productiva. Agencia Nacional de Promoción Científica y Tecnológica; ArgentinaFil: De Feudis, Leonardo. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Basilio, Alicia M.. Universidad de Buenos Aires. Facultad de Agronomía; ArgentinaFil: Galetto, Leonardo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto Multidisciplinario de Biología Vegetal. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas Físicas y Naturales. Instituto Multidisciplinario de Biología Vegetal; ArgentinaFil: Eguaras, Martin Javier. Universidad Nacional de Mar del Plata. Instituto de Investigaciones En Produccion, Sanidad y Ambiente. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mar del Plata. Instituto de Investigaciones En Produccion, Sanidad y Ambiente.; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Maggi, Matías Daniel. Universidad Nacional de Mar del Plata. Instituto de Investigaciones En Produccion, Sanidad y Ambiente. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mar del Plata. Instituto de Investigaciones En Produccion, Sanidad y Ambiente.; Argentina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales; Argentin

    Beekeeping as a strategy for environmental management in the basin Guaremal reservoir, municipality Peña, Yaracuy, Venezuela

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    El objetivo del presente estudio fue proponer estrategias de gestión ambiental para la recuperación de la cuenca del embalse Guaremal mediante el desarrollo de sistemas apícolas. Se realizó un relevamiento florístico alrededor de la cuenca tomando en consideración las especies visitadas por las abejas. Se determinaron las especies melíferas más abundantes de la zona en un área mínima de 0,10 ha definida en 7 transectos de 4m de ancho x 50m de largo, distribuidos a lo largo de toda la cuenca. La superficie fue dividida en tres zonas: baja (transectos 1 y 2), media (transectos 3, 4 y 5) y alta (transectos 6 y 7). Se estableció la densidad absoluta y relativa de cada especie vegetal dentro de cada transecto y entre todos los transectos. Se determinó la composición de la flora en la cuenca del embalse Guaremal, constituida por 77 especies de interés apícola, representadas en 40 familias, siendo las más predominantes: Compositae, Fabaceae, Mimosaceae, Euphorbiaceae y Urticaceae. La aparición de una especie apibotánica colonizadora, Wedelia caracasana, reveló un fuerte impacto antrópico negativo. Se proponen varias acciones correctivas, entre ellas el desarrollo de la Apicultura como estrategia de gestión ambiental para la recuperación de la cuenca del embalse Guaremal.The aim of this study was to propose different environmental management strategies for the recovery of the Guaremal Reservoir basin area, by developing beekeeping systems. A floristic screening was done around the Guaremal basin area taking into account the species visited by the bees. In order to determine the most abundant honey species of the region, a minimal area of 0.10 ha was established, defined by seven transects of 4m width by 50m long, laid out along the basin. The surface was also divided in three different zones: low (transects 1 and 2), medium (transects 3, 4 and 5) and high (transects 6 and 7). Absolute and relative plant species density was determined within each transect and among all of the transects. Floral composition in the Guaremal Reservoir basin area was registered and it consists of 77 species of beekeeping interest, represented by 40 different families, being the predominant ones Compositae, Fabaceae, Mimosaceae, Euphorbiaceae and Urticaceae. The appearance of a certain apibotanic plant species Wedelia. caracasana evealed a strongly negative anthropic effect. Several corrective actions were proposed, such as beekeeping activities as possible environmental control strategies, for the recovery of the Guaremal reservoir basin area.Fil: Barrios, Carlos. Universidad Centroccidental Lisandro Alvarado. Decanato de Ciencias Veterinarias. Estación de Apicultura; Venezuela;Fil: Morales, Yoel. Universidad Nacional Experimental de los Llanos “Ezequiel Zamora”; Venezuela;Fil: Cugnata, Noelia Melina. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología. Laboratorio de Artrópodos; Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Mar del Plata; Argentina;Fil: de Piano, Fiorella Giselle. Universidad Nacional de Mar del Plata. Facultad de Ciencias Agrarias. Departamento de Producción Animal. Cátedra de Apicultura; Argentina; Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Mar del Plata; Argentina;Fil: Fuselli, Sandra Rosa. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología. Laboratorio de Artrópodos; Argentina; Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Mar del Plata; Argentina;Fil: Maggi, Matías Daniel. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Departamento de Biología. Laboratorio de Artrópodos; Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Mar del Plata; Argentina;Fil: Melo, Hugo M.. Instituto Nacional de Tecnologia Agropecuaria; Argentina;Fil: Principal, Judith. Universidad Centroccidental Lisandro Alvarado. Decanato de Ciencias Veterinarias. Estación de Apicultura; Venezuela

    First determination of the one-proton induced Non-Mesonic Weak Decay width of p-shell {\Lambda}-Hypernuclei

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    Previous studies of proton and neutron spectra from Non-Mesonic Weak Decay of eight Lambda-Hypernuclei (A = 5-16) have been revisited. New values of the ratio of the two-nucleon and the one-proton induced decay widths, Gamma_2N/Gamma_p, are obtained from single proton spectra, Gamma_2N/Gamma_p = 0.50 +/- 0.24, and from neutron and proton coincidence spectra, Gamma_2N/Gamma_p = 0.36 +/- 0.14stat +0.05sys -0.04sys , in full agreement with previously published ones. With these values, a method is developed to extract the one-proton induced decay width in units of the free Lambda decay width, Gamma_p/Gamma_Lambda, without resorting to Intra Nuclear Cascade models but by exploiting only experimental data, under the assumption of a linear dependence on A of the Final State Interaction contribution. This is the first systematic determination ever done and it agrees within the errors with recent theoretical calculations.Comment: 16 pages, 3 figures, 2 table

    Long-Term Effects of Metformin and Lifestyle Modification on Nonalcoholic Fatty Liver Disease Obese Adolescents

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    Objective. To assess the long-term effects of metformin in combination with lifestyle intervention and its association between insulin levels and the degree of steatosis at ultrasonography (US) in obese adolescents. Methods. Thirty-five postpubertal obese boys were randomized into two groups: one receiving metformin in combination with a multidisciplinary lifestyle intervention versus a placebo group, which also received the same intervention. The visceral, subcutaneous fat and degree of steatosis were measured by ultrasonography. Fasting blood samples were collected to analyze glucose, insulin, insulin resistance, and aminotransferases. Repeated ANOVA measures were used to compare changes over time and between groups, and Spearman's correlations were used to identify an association between insulin and the degree of steatosis at US. Results. There was a positive correlation between the degree of steatosis at US with insulin concentrations and HOMA-IR. Long-term therapy plus metformin significantly reduced body weight, body mass index, insulin, HOMA-IR, and visceral fat. Conclusions. Metformin was more effective than the placebo in improving clinical parameters associated with obesity and steatosis

    Σp\Sigma^- p emission rates in KK^- absorptions at rest on 6^6Li, 7^7Li, 9^{9}Be, 13^{13}C and 16^{16}O

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    An experimental study of the KstopAΣpAK^-_{stop}A\rightarrow \Sigma^- p A' reaction on A=6A=^6Li, 7^7Li, 9^9Be, 13^{13}C and 16^{16}O pp-shell nuclei is presented. The data were collected by the FINUDA spectrometer operating at the DAΦ\PhiNE ϕ\phi-factory (LNF-INFN, Italy). Emission rates for the reaction in the mentioned nuclei are measured and compared with the few existing data. The spectra of several observables are discussed; indications of Quasi-Free absorptions by a (np)(np) pair embedded in the AA nucleus can be obtained from the study of the missing mass distributions.Comment: Version accepted by PR

    Prenatal tobacco smoke exposure increases hospitalizations for bronchiolitis in infants

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    BACKGROUND: Tobacco smoke exposure (TSE) is a worldwide health problem and it is considered a risk factor for pregnant women's and children's health, particularly for respiratory morbidity during the first year of life. Few significant birth cohort studies on the effect of prenatal TSE via passive and active maternal smoking on the development of severe bronchiolitis in early childhood have been carried out worldwide. METHODS: From November 2009 to December 2012, newborns born at ≥ 33 weeks of gestational age (wGA) were recruited in a longitudinal multi-center cohort study in Italy to investigate the effects of prenatal and postnatal TSE, among other risk factors, on bronchiolitis hospitalization and/or death during the first year of life. RESULTS: Two thousand two hundred ten newborns enrolled at birth were followed-up during their first year of life. Of these, 120 (5.4%) were hospitalized for bronchiolitis. No enrolled infants died during the study period. Prenatal passive TSE and maternal active smoking of more than 15 cigarettes/daily are associated to a significant increase of the risk of offspring children hospitalization for bronchiolitis, with an adjHR of 3.5 (CI 1.5-8.1) and of 1.7 (CI 1.1-2.6) respectively. CONCLUSIONS: These results confirm the detrimental effects of passive TSE and active heavy smoke during pregnancy for infants' respiratory health, since the exposure significantly increases the risk of hospitalization for bronchiolitis in the first year of lif
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