1,614 research outputs found

    Possible Association of Two Stellar Bowshocks with Unidentified <i>Fermi</i> Sources

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    The bowshocks of runaway stars had been theoretically proposed as gamma-ray sources. However, this hypothesis has not been confirmed by observations to date. In this paper, we present two runaway stars (λ Cep and LS 2355) whose bowshocks are coincident with the unidentified Fermi gamma-ray sources 3FLG J2210.1+5925 and 3FGL J1128.7-6232, respectively. After performing a cross-correlation between different catalogs at distinct wavelengths, we found that these bowshocks are the most peculiar objects in the Fermi position ellipses. Then we computed the inverse Compton emission and fitted the Fermi data in order to test the viability of both runaway stars as potential counterparts of the two high-energy sources. We obtained very reasonable values for the fitted parameters of both stars. We also evaluated the possibility for the source 3FGL J1128.7-6232, which is positionally coincident with a H II region, to be the result of background cosmic-ray protons interacting with the matter of the cloud, as well as the probability of a pure chance association. We conclude that the gamma rays from these Fermi sources might be produced in the bowshocks of the considered runaway stars. In such a case, these would be the first sources of this class ever detected at gamma rays.Facultad de Ciencias Astronómicas y Geofísica

    Marco teórico del efecto de interferencia en contextos neutrales y emocionales

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    Interference is the experimental effect caused by distracting information. It manifests as decreased performance in conditions with distracting information compared to performance in conditions without distracting information. Although many studies have investigated this effect, most of them have analysed it in neutral settings (i.e. settings without emotional salience). We review the interference effect, its temporal and formal dimensions, and settings in which it occurs (i.e. in neutral as well as emotionally charged settings), and different aspects of emotional settings that modulate the interference effect. Finally, we include different concepts that support the interference effect as the main explanatory mechanism of inhibitory control processes.La interferencia es el efecto experimental causado por información distractora que se manifiesta en una disminución del desempeño respecto a condiciones que implican ausencia de información distractora. Si bien existe un notorio cuerpo de literatura respecto a este efecto, la gran mayoría de los trabajos existentes lo analizan en contextos neutrales, es decir, sin saliencia emocional. Por este motivo, en este trabajo se revisará el efecto de interferencia, sus dimensiones temporales y formales, como así también los contextos en los que interviene, es decir no sólo los neutrales sino también aquellos con saliencia emocional. Con respecto a estos últimos, se revisan los diferentes aspectos de los contextos emocionales que modulan el efecto de interferencia. Finalmente, se incorporan diferentes nociones que han inclinado la balanza a favor del efecto de interferencia como el principal mecanismo explicativo de los procesos de control inhibitorio

    Rational Design of a Biocatalyst Based on Immobilized CALB onto Nanostructured SiO2

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    The adsorption of the lipase B from Candida antarctica (CALB) over nanostructured SiO2 (Ns SiO2 from now on) with and without the addition of polyols (sorbitol and glycerol) was investigated. The isotherms of adsorption made it possible to establish that the maximum dispersion limit was 0.029 µmol of protein per surface area unit of Ns SiO2 (29.4 mg per 100 mg of support), which was reached in 30 min of exposure. The studies through SDS-PAGE of the immobilization solutions and infrared spectroscopy of the prepared solids determined that CALB (from a commercial extract) is selectively adsorbed, and its secondary structure distribution is thus modified. Its biocatalytic activity was corroborated through the kinetic resolution of rac-ibuprofen. Conversions of up to 70% and 52% enantiomeric excess toward S-ibuprofen in 24 h of reaction at 45 °C were achieved. The biocatalytic performance increased with the increase in protein loading until it leveled off at 0.021 µmol.m−2, reaching 0.6 µmol.min−1. The biocatalyst containing the lipase at the maximum dispersion limit and co-adsorbed polyols presented the best catalytic performance in the kinetic resolution of rac-ibuprofen, an improved thermal resistance (up to 70 °C), and stability under long-term storage (more than 2 years).Fil: Llerena Suster, Carlos Rafael. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Ciencias Biológicas. Laboratorio de Investigación de Proteínas Vegetales; ArgentinaFil: Toledo, María V.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; ArgentinaFil: Matkovic, Silvana Raquel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; ArgentinaFil: Morcelle del Valle, Susana Raquel. Universidad Nacional de La Plata. Facultad de Ciencias Exactas. Departamento de Ciencias Biológicas. Laboratorio de Investigación de Proteínas Vegetales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Briand, Laura Estefania. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Centro de Investigación y Desarrollo en Ciencias Aplicadas "Dr. Jorge J. Ronco". Universidad Nacional de la Plata. Facultad de Ciencias Exactas. Centro de Investigación y Desarrollo en Ciencias Aplicadas; Argentin

    AE Aurigae: First detection of non-thermal X-ray emission from a bow shock produced by a runaway star

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    Runaway stars produce shocks when passing through interstellar medium at supersonic velocities. Bow shocks have been detected in the mid-infrared for several high-mass runaway stars and in radio waves for one star. Theoretical models predict the production of high-energy photons by non-thermal radiative processes in a number sufficiently large to be detected in X-rays. To date, no stellar bow shock has been detected at such energies. We present the first detection of X-ray emission from a bow shock produced by a runaway star. The star is AE Aur, which was likely expelled from its birthplace due to the encounter of two massive binary systems and now is passing through the dense nebula IC 405. The X-ray emission from the bow shock is detected at 30″ northeast of the star, coinciding with an enhancement in the density of the nebula. From the analysis of the observed X-ray spectrum of the source and our theoretical emission model, we confirm that the X-ray emission is produced mainly by inverse Compton upscattering of infrared photons from dust in the shock front.Instituto Argentino de RadioastronomíaFacultad de Ciencias Astronómicas y Geofísica

    Layer-dependence of macroscopic and atomic magnetic correlations in Co/Pd multilayers

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    The development of multilayered materials with engineered magnetic properties compels a deep knowledge of physical properties at the atomic scale. The magnetic anisotropy is a key property in these materials. This work accounts for the magnetic anisotropy energy and its correlation with atomic properties of Co/Pd multilayers with the number of Co/Pd repetitions. Magnetometry measurements confirm stronger perpendicular magnetic anisotropy energies as the number of repetitions increases up to 40. However, the intrinsic anisotropy, related to the Co-Pd orbital hybridization and spin-orbit coupling, saturates at 15 repetitions. This finding is supported by x-ray magnetic circular dichroism analysis that reveals a direct correlation of the atomic Co and Pd orbital magnetic moments and the effective anisotropy of the system. The proximity effect that accounts for the Pd induced magnetization, along with the increasing Co moment, provides a suitable mechanism for the observed anisotropy energy layer dependence

    Uncontrolled donation programs after out-of-hospital cardiac arrest. An estimation of potential donors.

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    Objective To determine the number of potential deceased organ donors from out-of- hospital cardiac arrest cases (OHCA) attended by public physician-led emergency medical services in Spain, based on data recorded in the nationwide Spanish OHCA Registry (OHSCAR). Material and methods We analysed OHSCAR data on deceased OHCA patients in Spain during 13 months (1/10/2013 to 31/10/ 2014). Variables included age, sex, estimated OHCA time, cardiopulmonary resuscitation (CPR) start time and outcome. Inclusion criteria were: age 16–60 years, witnessed OHCA, no return of spontaneous circulation (ROSC) and time interval <15 min between OHCA occurrence and CPR initiation. Results Of a total 8789 cases, 3290 met the age criteria; of these, CPR was not witnessed in 745 cases. Among the remaining 2545 patients, 141 were included in uncontrolled donation after cardiac death (uDCD) programs, 902 arrived at the hospital with ROSC, 64 arrived with ongoing CPR and 15 cases were lost to follow-up. Of the remaining 1423 without ROSC, CPR initiation time was not recorded in 454 cases and 398 did not meet the time criteria <15 min between OHCA and CPR initiation. Finally, 571 met all the criteria and could have been potential donors. There were significant differences in the actual donors percentage from potential donors percentage between provinces with and without donor programs (141/322 = 43.8% versus 0/390 = 0%), but there were no differences in ROSC between the two types of provinces (418/1320 = 31.7% versus 652/1970 = 33.4%). Conclusions Many potential donors are missed in current clinical practice. uDCD programs are few and underused even in a country with high rates of organs transplantation.pre-print820 K

    Vortex dynamics controlled by local superconducting enhancement

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    A controlled local enhancement of superconductivity yields unexpected modifications in the vortex dynamics. This local enhancement has been achieved by designing an array of superconducting Nb nanostructures embedded in a V superconducting film. The most remarkable findings are: (i) vanishing of the main commensurability effect between the vortex lattice and the array unit cell, (ii) hysteretic behavior in the vortex dynamics, (iii) broadening of the vortex liquid phase and (iv) strong softening of the vortex lattice. These effects can be controlled and they can be quenched by reducing the Nb array superconducting performance applying an in-plane magnetic field. These results can be explained by taking into account the repulsive potential landscape created by the superconducting Nb nanostructures on which vortices move

    Dasatinib-induced spleen contraction leads to transient lymphocytosis

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    The tyrosine kinase inhibitor dasatinib is approved for Philadelphia chromosome–positive leukemia, including chronic myeloid leukemia (CML). Although effective and well tolerated, patients typically exhibit a transient lymphocytosis after dasatinib uptake. To date, the underlying physiological process linking dasatinib to lymphocytosis remains unknown. Here, we used a small rodent model to examine the mechanism of dasatinib-induced lymphocytosis, focusing on lymphocyte trafficking into and out of secondary lymphoid organs. Our data indicate that lymphocyte homing to lymph nodes and spleen remained unaffected by dasatinib treatment. In contrast, dasatinib promoted lymphocyte egress from spleen with kinetics consistent with the observed lymphocytosis. Unexpectedly, dasatinib-induced lymphocyte egress occurred independently of canonical sphingosine-1-phosphate–mediated egress signals; instead, dasatinib treatment led to a decrease in spleen size, concomitant with increased splenic stromal cell contractility, as measured by myosin light chain phosphorylation. Accordingly, dasatinib-induced lymphocytosis was partially reversed by pharmacological inhibition of the contraction-promoting factor Rho-rho associated kinase. Finally, we uncovered a decrease in spleen size in patients with CML who showed lymphocytosis immediately after dasatinib treatment, and this reduction was proportional to the magnitude of lymphocytosis and dasatinib plasma levels. In summary, our work provides evidence that dasatinib-induced lymphocytosis is a consequence of drug-induced contractility of splenic stromal cell
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