208 research outputs found

    IAC-Star: a Code for Synthetic Color-Magnitude Diagram Computation

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    The code IAC-star is presented. It generates synthetic HR and color-magnitude diagrams (CMDs) and is mainly aimed to star formation history studies in nearby galaxies. Composite stellar populations are calculated on a star by star basis, by computing the luminosity, effective temperature and gravity of each star by direct bi-logarithmic interpolation in the metallicity and age grid of a library of stellar evolution tracks. Visual (broad band and HST) and infrared magnitudes are also provided for each star after applying bolometric corrections. The Padua (Bertelli et al. 1994, Girardi et al. 2000) and Teramo (Pietrinferni et al. 2004) stellar evolution libraries and various bolometric corrections libraries are used in the current version. A variety of star formation rate functions, initial mass functions and chemical enrichment laws are allowed and binary stars can be computed. Although the main motivation of the code is the computation of synthetic CMDs, it also provides integrated masses, luminosities and magnitudes as well as surface brightness fluctuation luminosities and magnitudes for the total synthetic stellar population, and therefore it can also be used for population synthesis research. The code is offered for free use and can be executed at the site {\tt http://iac-star.iac.es}, with the only requirement of referencing this paper and crediting as indicated in the site.Comment: Astronomical Journal, in pres

    Smart IoT soundproofing panels for enhanced environmental comfort

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    In the context of Ambient Assisted Living, the SISSI project aims to integrate soundproofing panels with IoT technologies, developing a new modular system to improve the comfort of people living and working in shared environments by taking advantage of the acoustic properties of the panels and the automatic monitoring of some relevant environmental variables. To reach a satisfying solution the need to experiment with different technologies arose, and thus the team needed to share observations, problems, and solutions right from the design phase. The first step was checking if perforating the company's current sound-absorbing panels and incorporating electronic components would affect their efficiency, measuring the material's performances in the laboratory to verify its sound absorption value. Measurements were conducted in compliance with ISO 354 standards, assessing both types of sound-absorbing materials in various configurations. They show that arranging the material in a checkerboard pattern or in "thinned" lines is more advantageous in terms of absorption. Indeed, the laboratory tests have shown that a smaller amount of material results in better sound-absorbing characteristics. With this data, the final IoT panel will be more sustainable because less material can be used. In the second step, new panels with integrated sensors to monitor temperature, humidity, CO2, brightness, and people's presence were tested. Based on the data collected, the team defined the functions of the panel, which will be able to monitor the level of air oxygenation and control room or desk brightness level and to switch on or off when the user is present, thus reducing energy consumption. The experimental results changed the redesign of the panels, which now feature accessible electronic components and an interior that is not fully packed with material. Furthermore, the system is designed to integrate additional elements, such as lighting and electronic devices, for seamless interaction with the surrounding environment. Importantly, the sound-absorbing panel system will also provide clear user signals about the monitoring status, enhancing comfort

    22Ne and 23Na ejecta from intermediate-mass stars: The impact of the new LUNA rate for 22Ne(p,gamma)23Na

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    We investigate the impact of the new LUNA rate for the nuclear reaction 22^{22}Ne(p,γ)23(p,\gamma)^{23}Na on the chemical ejecta of intermediate-mass stars, with particular focus on the thermally-pulsing asymptotic giant branch (TP-AGB) stars that experience hot-bottom burning. To this aim we use the PARSEC and COLIBRI codes to compute the complete evolution, from the pre-main sequence up to the termination of the TP-AGB phase, of a set of stellar models with initial masses in the range 3.0 M⊙−6.0 M⊙3.0\,M_{\odot} - 6.0\,M_{\odot}, and metallicities Zi=0.0005Z_{\rm i}=0.0005, Zi=0.006Z_{\rm i}=0.006, and Zi=0.014Z_{\rm i} = 0.014. We find that the new LUNA measures have much reduced the nuclear uncertainties of the 22^{22}Ne and 23^{23}Na AGB ejecta, which drop from factors of ≃10\simeq 10 to only a factor of few for the lowest metallicity models. Relying on the most recent estimations for the destruction rate of 23^{23}Na, the uncertainties that still affect the 22^{22}Ne and 23^{23}Na AGB ejecta are mainly dominated by evolutionary aspects (efficiency of mass-loss, third dredge-up, convection). Finally, we discuss how the LUNA results impact on the hypothesis that invokes massive AGB stars as the main agents of the observed O-Na anti-correlation in Galactic globular clusters. We derive quantitative indications on the efficiencies of key physical processes (mass loss, third dredge-up, sodium destruction) in order to simultaneously reproduce both the Na-rich, O-poor extreme of the anti-correlation, and the observational constraints on the CNO abundance. Results for the corresponding chemical ejecta are made publicly available

    Outer density profiles of 19 Galactic globular clusters from deep and wide-field imaging

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    Using deep photometric data from WFC@INT and [email protected] we measure the outer number density profiles of 19 stellar clusters located in the inner region of the Milky Way halo (within a Galactocentric distance range of 10-30 kpc) in order to assess the impact of internal and external dynamical processes on the spatial distribution of stars. Adopting power-law fitting templates, with index −γ-\gamma in the outer region, we find that the clusters in our sample can be divided in two groups: a group of massive clusters (≄105 \ge 10^5 M_sun) that has relatively flat profiles with 2.5<Îł<42.5 < \gamma < 4 and a group of low-mass clusters (≀105 \le 10^5 M_sun), with steep profiles (Îł>4\gamma > 4) and clear signatures of interaction with the Galactic tidal field. We refer to these two groups as 'tidally unaffected' and 'tidally affected', respectively. Our results also show a clear trend between the slope of the outer parts and the half-mass density of these systems, which suggests that the outer density profiles may retain key information on the dominant processes driving the dynamical evolution of Globular Clusters.Comment: 17 pages, 14 figures, 2 tables; accepted for publication in MNRA

    Novel cetacean morbillivirus in Guiana dolphin, Brazil

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    We thank Ariosvaldo Pinto dos Santos and volunteers for the valuable help during the fieldwork; Projeto TAMAR and Parque Estadual de ItaĂșnas for reporting stranded marine mammals and providing logistical support in many stranding events; Jane Megid, Adriana Cortez, Susan D. Allendorf, CĂ­ntia Maria Favero, and laboratory staffs from participating institutions for assistance during analysis; and the journal editor and 2 anonymous reviewers for their constructive comments. Fundação de Amparo Ă  Pesquisa do Estado de SĂŁo Paulo provided grants (processes 2010/50094-3, 2011/08357-0 and 2012/00021-5), which are greatly appreciated. Veracel Celulose provided financial support to the Rescue Program. Projeto Baleia Jubarte is sponsored by Petroleo Brasileiro (Petrobras). J.L.C.-D. is a recipient of a professorship by the Conselho Nacional de Desenvolvimento CientĂ­fico e TecnolĂłgico–CNPq (301517/2006-1).FAPESPT - Processes 2010/50094-3, 2011/08357-0 and 2012/00021-5CNPq - 301517/2006-1Carta ao Editor

    A Relay Pathway between Arginine and Tryptophan Metabolism Confers Immunosuppressive Properties on Dendritic Cells

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    Arginase 1 (Arg1) and indoleamine 2,3-dioxygenase 1\ua0(IDO1) are immunoregulatory enzymes catalyzing the degradation of L-arginine and L-tryptophan, respectively, resulting in local amino acid deprivation. In addition, unlike Arg1, IDO1 is also endowed with non-enzymatic signaling activity in dendritic cells (DCs). Despite considerable knowledge of their individual biology, no integrated functions of Arg1 and IDO1 have been reported yet. We found that IDO1 phosphorylation and consequent activation of IDO1 signaling in DCs was strictly dependent on prior expression of Arg1 and Arg1-dependent production of polyamines. Polyamines, either produced by DCs or released by bystander Arg1+ myeloid-derived suppressor cells, conditioned DCs toward an IDO1-dependent, immunosuppressive phenotype via activation of the Src kinase, which has IDO1-phosphorylating activity. Thus our data indicate that Arg1 and IDO1 are linked by an entwined pathway in immunometabolism and that their joint modulation could represent an important target for effective immunotherapy in several disease settings

    Improved astrophysical rate for the 18O(p,α)15N reaction by underground measurements

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    The 18O(p,\u3b1)15N reaction affects the synthesis of 15N, 18O and 19F isotopes, whose abundances can be used to probe the nucleosynthesis and mixing processes occurring deep inside asymptotic giant branch (AGB) stars. We performed a low-background direct measurement of the 18O(p,\u3b1)15N reaction cross-section at the Laboratory for Underground Nuclear Astrophysics (LUNA) from center of mass energy Ec.m.=340keV down to Ec.m.=55keV, the lowest energy measured to date corresponding to a cross-section of less than 1 picobarn/sr. The strength of a key resonance at center of mass energy Er=90keV was found to be a factor of 10 higher than previously reported. A multi-channel R-matrix analysis of our and other data available in the literature was performed. Over a wide temperature range, T=0.01\u20131.00GK, our new astrophysical rate is both more accurate and precise than recent evaluations. Stronger constraints can now be placed on the physical processes controlling nucleosynthesis in AGB stars with interesting consequences on the abundance of 18O in these stars and in stardust grains, specifically on the production sites of oxygen-rich Group II grains
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