12,937 research outputs found

    XNAT-PIC: Extending XNAT to Preclinical Imaging Centers

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    Molecular imaging generates large volumes of heterogeneous biomedical imagery with an impelling need of guidelines for handling image data. Although several successful solutions have been implemented for human epidemiologic studies, few and limited approaches have been proposed for animal population studies. Preclinical imaging research deals with a variety of machinery yielding tons of raw data but the current practices to store and distribute image data are inadequate. Therefore, standard tools for the analysis of large image datasets need to be established. In this paper, we present an extension of XNAT for Preclinical Imaging Centers (XNAT-PIC). XNAT is a worldwide used, open-source platform for securely hosting, sharing, and processing of clinical imaging studies. Despite its success, neither tools for importing large, multimodal preclinical image datasets nor pipelines for processing whole imaging studies are yet available in XNAT. In order to overcome these limitations, we have developed several tools to expand the XNAT core functionalities for supporting preclinical imaging facilities. Our aim is to streamline the management and exchange of image data within the preclinical imaging community, thereby enhancing the reproducibility of the results of image processing and promoting open science practices

    Avaliação do desempenho de um pivo central da baixa pressão equipado com tubos de descida.

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    At the Corn and Sorghum National Research Center in Sete Lagoas, Minas Gerais State, an evaluation was made of the performance of a low pressure central pivot equipped with drop sparay, operating at 100% of its displacement capacity. The tests carried out were the following: without drop spray; drop spray of 1.2m; 2.0m and 2.6m lenght. For each test, the uniformity coefficients of Christiansen (CUC) and distribution (CUD), the application efficiency, in potential (EPa), and the highest precipitation intensity were determined. It was concluded that: The lenght of drop spray did not affect distribution uniformity; The collected water plate at the end of the pivot line showed a large variation; Topographic characteristics influenced distribution uniformity; Drop spray increased application efficiency, in potential, reducing pressure at the diffusor exit. Proximity of the diffusor to the ground decreased the covering diameter and increase precipitation density

    Total CO2 output from Ischia Island volcano (Italy)

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    The total amount of CO2 released at Ischia Island has been estimated from soil gas flux measurements and from chemical composition of the gases released by fumaroles or dissolved in groundwaters. The preliminary results indicate an overall CO2 output of about 15 kg s–1 from the entire island (46 km2). The main contribution to the total output from diffuse soil degassing is about 14.8 kg s–1, followed by dissolved CO2 of about 0.3 kg s–1. The contribution of fumaroles to the total output was found to be negligible (about 0.03 kg s–1). Ischia’s output, although being considerably less than that of open conduit volcanoes, is higher than many other volcanic systems, especially those related to volcanic arcs. The recent tensile tectonic regime of the area allows probably an easier upflow of CO2 from the mantle sustaining the diffuse degassing of the island

    SURVEY ON FLUORIDE, BROMIDE, CHLORIDE, NITRATE AND SULPHATE CONTENTS IN PUBLIC DRINKING WATER SUPPLIES IN SICILY (ITALY)

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    Six hundred and sixty-seven water samples were collected from public drinking water supplies in Sicily and analysed for electric conductivity and for their chloride, bromide, fluoride, sulphate and nitrate contents. The samples were, as far as possible, collected evenly over the entire territory with an average sampling density of about one sample for every 7600 inhabitants. The contents of chloride and bromide, ranging between 5.53 and 1302 mg/l and between < 0.025 and 4.76 mg/l respectively, correlated well with the electric conductivity, a parameter used as a proxy for water salinity. The highest values were found both along the NW and SE coasts, which we attributed to seawater contamination, and in the central part of Sicily, which we attributed to evaporitic rock dissolution. The nitrate concentrations were in the range 0.05 – 296 mg/l. Of the analysed samples about 4.4% exceeded the maximum admissible concentration (MAC) of 50 mg/l. The highest values were always measured in areas of intense agricultural exploitation. The sulphate concentrations varied between 6.03 and 516 mg/l, exceeding in about 1.2% of the cases the guideline level of 250 mg/l. The highest values were always related either to evaporitic rock dissolution or to seawater intrusion. The fluoride concentrations ranged from 0.023 to 3.28 mg/l, while the highest values (only 3 exceeding the MAC of 1.5 mg/l) generally attributed either to the leaching of crystalline (volcanic or metamorphic) or evaporitic rocks or to contamination from a hydrothermal component. Apart from these limited cases of exceeding of MACs, the waters of public drinking water supplies in Sicily can be considered safe for human consumption for the analysed parameters. Some limited concern could arise from the intake of bromide-rich waters (about 3% exceeding 1 mg/l) because of the potential formation of dangerous disinfection by-products. Also nitrate concentrations, although sometimes exceeding MAC, display generally level well suited for human consumption, the population-weighted average being about 16 mg/l for the whole Sicily. As regards geographic distribution, the best water quality was found in areas with the most humid climate and with huge aquifers in the north-eastern part of the island. On the contrary especially along the southern coasts of Sicily, arid conditions and the widespread presence of impermeable lithologies, sometimes forces the use of low quality water resources. But it is also worth to note that bad management often exacerbates water quality and quantity problems in these areas

    Properties of the ferrimagnetic double-perovskite A_{2}FeReO_{6} (A=Ba and Ca)

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    Ceramics of A_{2}FeReO_{6} double-perovskite have been prepared and studied for A=Ba and Ca. Ba_{2}FeReO_{6} has a cubic structure (Fm3m) with aa\approx 8.0854(1) \AA whereas Ca_{2}FeReO_{6} has a distorted monoclinic symmetry with a5.396(1)A˚,b5.522(1)A˚,c7.688(2)A˚a\approx 5.396(1) \AA, b\approx 5.522(1) \AA, c\approx 7.688(2) \AA and β=90.4(P21/n)\beta =90.4^{\circ} (P21/n). The barium compound is metallic from 5 K to 385 K, i.e. no metal-insulator transition has been seen up to 385 K, and the calcium compound is semiconducting from 5 K to 385 K. Magnetization measurements show a ferrimagnetic behavior for both materials, with T_{c}=315 K for Ba_{2}FeReO_{6} and above 385 K for Ca_{2}FeReO_{6}. A specific heat measurement on the barium compound gave an electron density of states at the Fermi level, N(E_{F}) equal to 6.1×1024eV1mole1\times 10^{24} eV^{-1}mole^{-1}. At 5 K, we observed a negative magnetoresistance of 10 % in a magnetic field of 5 T, but only for Ba_{2}FeReO_{6}. Electrical, thermal and magnetic properties are discussed and compared to the analogous compounds Sr_{2}Fe(Mo,Re)O_{6}.Comment: 5 pages REVTeX, 7 figures included, submitted to PR

    Elucidating the real-time Ag nanoparticle growth on alpha-Ag2WO4 during electron beam irradiation: experimental evidence and theoretical insights

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    FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORWhy and how Ag is formed when electron beam irradiation takes place on alpha-Ag2WO4 in a vacuum transmission electron microscopy chamber? To find an answer, the atomic-scale mechanisms underlying the formation and growth of Ag on alpha-Ag2WO4 have been investigated by detailed in situ transmission electron microscopy (TEM) and field emission scanning electron microscopy (FE-SEM) studies, density functional theory based calculations and ab initio molecular dynamics simulations. The growth process at different times, chemical composition, size distribution and element distribution were analyzed in depth at the nanoscale level using FE-SEM, operated at different voltages (5, 10, 15, and 20 kV), and TEM with energy dispersive spectroscopy (EDS) characterization. The size of Ag nanoparticles covers a wide range of values. Most of the Ag particles are in the 20-40 nm range. The nucleation and formation of Ag on alpha-Ag2WO4 is a result of structural and electronic changes in the AgOx (x = 2,4, 6, and 7) clusters used as constituent building blocks of this material, consistent with metallic Ag formation. First principle calculations point out that Ag-3 and Ag-4-fold coordinated centers, located in the sub-surface of the (100) surface, are the most energetically favorable to undergo the diffusion process to form metallic Ag. Ab initio molecular dynamics simulations and the nudged elastic band (NEB) method were used to investigate the minimum energy pathways of these Ag atoms from positions in the first slab layer to outward sites on the (100) surface of alpha-Ag2WO4. The results point out that the injection of electrons decreases the activation barrier for this diffusion step and this unusual behavior results from the presence of a lower energy barrier process.Why and how Ag is formed when electron beam irradiation takes place on alpha-Ag2WO4 in a vacuum transmission electron microscopy chamber? To find an answer, the atomic-scale mechanisms underlying the formation and growth of Ag on alpha-Ag2WO4 have been investigated by detailed in situ transmission electron microscopy (TEM) and field emission scanning electron microscopy (FE-SEM) studies, density functional theory based calculations and ab initio molecular dynamics simulations. The growth process at different times, chemical composition, size distribution and element distribution were analyzed in depth at the nanoscale level using FE-SEM, operated at different voltages (5, 10, 15, and 20 kV), and TEM with energy dispersive spectroscopy (EDS) characterization. The size of Ag nanoparticles covers a wide range of values. Most of the Ag particles are in the 20-40 nm range. The nucleation and formation of Ag on alpha-Ag2WO4 is a result of structural and electronic changes in the AgOx (x = 2,4, 6, and 7) clusters used as constituent building blocks of this material, consistent with metallic Ag formation. First principle calculations point out that Ag-3 and Ag-4-fold coordinated centers, located in the sub-surface of the (100) surface, are the most energetically favorable to undergo the diffusion process to form metallic Ag. Ab initio molecular dynamics simulations and the nudged elastic band (NEB) method were used to investigate the minimum energy pathways of these Ag atoms from positions in the first slab layer to outward sites on the (100) surface of alpha-Ag2WO4. The results point out that the injection of electrons decreases the activation barrier for this diffusion step and this unusual behavior results from the presence of a lower energy barrier process.17753525359FAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORFAPESP - FUNDAÇÃO DE AMPARO À PESQUISA DO ESTADO DE SÃO PAULOCNPQ - CONSELHO NACIONAL DE DESENVOLVIMENTO CIENTÍFICO E TECNOLÓGICOCAPES - COORDENAÇÃO DE APERFEIÇOAMENTO DE PESSOAL DE NÍVEL SUPERIORFAPESP [2013/07296-2, 2012/14468-1, 2010/16970-0, 2013/02032-7]CNPq [573636/2008-7, 150753/2013-6]CAPES [088/2013]2010/16970-02012/14468-12013/02032-72013/07296-2573636/2008-7150753/2013-6088/2013The authors are grateful to Prometeo/2009/053 (GeneralitatValenciana), Ministerio de Economia y Competitividad (Spain), CTQ2012-36253-C03-02, Spanish Brazilian program (PHB2009-0065-PC), FAPESP (Project 2013/07296-2) (Project 2012/14468-1) (Project 2010/16970-0), grant (2013/02032-7), CAPES and CNPq (Project 573636/2008-7, Grant 150753/2013-6) and CAPES (Project 088/2013) for financially supporting this research. Most of the calculations were performed using IFGW-UNICAMP computer facilities and the National Center for High Performance Computing in São Paulo (CENAPAD-SP). We also acknowledge the Servei Informática, Universitat Jaume I, for the generous allotment of computer time
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