727 research outputs found

    Detailed study of SNR G306.3-0.9 using XMM-Newton and Chandra observations

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    We used combined data from XMM-Newton and Chandra observatories to study the X-ray morphology of SNR G306.3-0.9. A spatially-resolved spectral analysis was used to obtain physical and geometrical parameters of different regions of the remnant. Spitzer infrared observations were also used to constrain the progenitor supernova and study the environment in which the SNR evolved. The X-ray morphology of the remnant displays a non-uniform structure of semi-circular appearance, with a bright southwest region and very weak or almost negligible X-ray emission in its northern part. These results indicate that the remnant is propagating in a non-uniform environment as the shock fronts are encountering a high-density medium, where enhanced infrared emission is detected. The X-ray spectral analysis of the selected regions shows distinct emission-line features of several metal elements, confirming the thermal origin of the emission. The X-ray spectra are well represented by a combination of two absorbed thermal plasma models: one in equilibrium ionization with a mean temperature of ~0.19 keV, and another out of equilibrium ionization at a higher temperature of ~1.1 or 1.6-1.9 keV. For regions located in the northeast, central, and southwest part of the SNR, we found elevated abundances of Si, S, Ar, Ca, and Fe, typical of ejecta material. The outer regions located northwest and south show values of the abundances above solar but lower than to those found in the central regions. This suggests that the composition of the emitting outer parts of the SNR is a combination of ejecta and shocked material of the interstellar medium. The comparison between the S/Si, Ar/Si, and Ca/Si abundances ratios (1.75, 1.27, and 2.72 in the central region, respectively), favor a Type Ia progenitor for this SNR, a result that is also supported by an independent morphological analysis using X-ray and IR data.Comment: 8 pages, 7 figures. Accepted by Astronomy and Astrophysic

    Sistema educativo, ética y crisis

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    La carencia de Educación Económico-Financiera que las sociedades desarrolladas, en general, y la española, en particular, padecen, tiene mucho que ver con la actual situación de crisis. La Educación Económico-Financiera tiene una doble vertiente, primera, de dotar al individuo de una formación de contenidos y, segunda, la componente Ético-Moral asociada a toda buena educación. En esta comunicación analizamos los aspectos de la educación que competen a la Educación Económico Financiera y los planes que hay en marcha, así como la actual crisis ha puesto de manifiesto las carencias existentes en el sistema educativo.Universidad de Málaga. Campus de Excelencia Internacional Andalucía Tech

    Resonant Photocurrent Generation in Dye-Sensitized Periodically Nanostructured Photoconductors by Optical Field Confinement Effects

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    Herein we show experimental evidence of resonant photocurrent generation in dye-sensitized periodically nanostructured photoconductors, which is achieved by spectral matching of the sensitizer absorption band to different types of localized photon modes present in either periodic or broken symmetry structures. Results are explained in terms of the calculated spatial distribution of the electric field intensity within the configurations under analysis.Unión Europea FP7 / 2007-2013Convenio de subvención ERC 307081 (POLIGHT)Ministerio de Economía y Competitividad MAT2011- 23593CONSOLIDER HOPE CSD2007-00007Junta de Andalucía FQM3579Junta de Andalucía FQM524

    Highly active catalytic Ru/TiO2 nanomaterials for continuous production of γ-valerolactone

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    Green energy production from renewable sources is an attractive but challenging topic to face the likely energy crisis scenario in the future. In the current work, a series of versatile Ru/TiO2 catalysts were simply synthesized and employed in continuous flow catalytic transfer hydrogenation of industrially derived methyl levulinate biowaste (from Avantium Chemicals B.V.) to γ-valerolactone. Different analytical techniques were applied in the characterization of the as-synthesized catalysts, including XRD, SEM, EDX, TEM and XPS etc. The effects of various reaction conditions (e.g. temperature, concentration and flow rate) were investigated. Results suggested that optimum dispersion and distribution of Ru on the TiO2 surface could efficiently promote production of γ-valerolactone, with 5% Ru/TiO2 catalyst providing excelling catalytic performance and stability as compared to commercial Ru catalysts

    Synthesis and catalytic activity of well-defined Co(i) complexes based on NHC–phosphane pincer ligands

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    A new methodology for the preparation of Co(I)–NHC (NHC = N-heterocyclic carbene) complexes, namely, [Co(PCNHCP)(CO)2][Co(CO)4] (1) and [Co(PCNHCP)(CO)2]BF4 (2), has been developed (PCNHCP = 1,3-bis(2-(diphenylphosphanyl)ethyl)-imidazol-2-ylidene). Both complexes can be straightforwardly prepared by direct reaction of their parent imidazolium salts with the Co(0) complex Co2(CO)8. Complex 1 efficiently catalyses the reductive amination of furfural and levulinic acid employing silanes as reducing agents under mild conditions. Furfural has been converted into a variety of secondary and tertiary amines employing dimethyl carbonate as the solvent, while levulinic acid has been converted into pyrrolidines under solventless conditions. Dehydrocoupling of the silane to give polysilanes has been observed to occur as a side reaction of the hydrosilylation process

    Ultrastable CoxSiyOz Nanowires by Glancing Angle Deposition with Magnetron Sputtering as Novel Electrocatalyst for Water Oxidation

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    Cobalt is one of the most promising non‐noble metal as electrocatalyst for water oxidation. Herein, a highly stable silicon‐cobalt mixed oxide thin film with a porous columnar nanostructure is proposed as electrocatalyst for oxygen evolution reaction (OER). CoOx and CoxSiyOz layers with similar thickness were fabricated at room temperature by magnetron sputtering in a glancing angle configuration (MS‐GLAD) on tin‐doped indium oxide (ITO) substrates. After characterization, a comparative study of the electrocatalytic performance for OER of both layers was carried out. The excellent long‐term stability as electrocatalyst for OER of the porous CoxSiyOz thin film demonstrates that the presence of silicon on the mixed oxide network increases the mechanical stability of the Si/Co layer, whilst maintaining a considerable electrocatalytic response

    Influence of glycerin and lecithin inclusion in the diet on liver characteristics and lipid fraction in the serum of brownegg laying hens at 55 week of age

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    The effects of the inclusion of raw glycerin (GLYC) and raw lecithin, in the diet (23 to 55 wk) on liver characteristics and various serum lipid fractions were studied in brown egg-laying hens at 55 wk of age. The control diets were based on corn, soybean meal, and 4% supplemental fat and contained 2,750 kcal AMEn/kg, 16.5% CP, and 0.73% digestible Lys. The diets were arranged as a 2 × 3 factorial with 2 levels of GLYC (0 and 7%) and 3 animal fat to lecithin ratios (4:0, 2:2, and 0:4%). Each treatment was replicated 8 times and the experimental unit was a cage with 10 hens. At 55 wk of age, 2 hens per cage replicate were randomly selected, weighed individually, and slaughtered by CO2 inhalation. Liver was immediately removed and weighed and the color recorded by spectrophotometry. In addition, blood samples from one bird per replicate were collected from the wing vein and the concentration of total cholesterol, low and high density lipoprotein cholesterol, and triglycerides were determined. The data were analyzed as a completely randomized design and the main effects of GLYC and lecithin content of the diet and the interactions were determined. No interactions between GLYC and lecithin content of the diets were detected for any of the variables studied. Liver characteristics and serum lipid traits were not affected by the inclusion of GLYC in the diet. The substitution of animal fat by lecithin, however, reduced the redness (a* 14.9 to 13.8) and yellowness (b* 8.60 to 7.20) values of the liver (P < 0.05) but did not affect the content of serum lipid fractions. It is concluded that the inclusion of GLYC and lecithin in the diet did not affect liver size or serum lipid fraction. However, the inclusion of lecithin reduced the a* and b* value of the live

    Heap-based Algorithms to Accelerate Fingerprint Matching on Parallel Platforms

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    Nowadays, fingerprint is the most used biometric trait for individuals identification. In this area, the state-of-the-art algorithms are very accurate, but when the database contains millions of identities, an acceleration of the algorithm is required. From these algorithms, Minutia Cylinder-Code (MCC) stands out for its good results in terms of accuracy, however its efficiency in computational time is not high. In this work, we propose to use two different parallel platforms to accelerate fingerprint matching process by using MCC: (1) a multi-core server, and (2) a Xeon Phi coprocessor. Our proposal is based on heaps as auxiliary structure to process the global similarity of MCC. As heap-based algorithms are exhaustive (all the elements are accessed), we also explored the use an indexing algorithm to avoid comparing the query against all the fingerprints of the database. Experimental results show an improvement up to 97.15x of speed-up, which is competitive compared to other state-of-the-art algorithms in GPU and FPGA. To the best of our knowledge, this is the first work for fingerprint identification using a Xeon Phi coprocessor.Instituto de Investigación en Informátic

    Heap-based Algorithms to Accelerate Fingerprint Matching on Parallel Platforms

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    Nowadays, fingerprint is the most used biometric trait for individuals identification. In this area, the state-of-the-art algorithms are very accurate, but when the database contains millions of identities, an acceleration of the algorithm is required. From these algorithms, Minutia Cylinder-Code (MCC) stands out for its good results in terms of accuracy, however its efficiency in computational time is not high. In this work, we propose to use two different parallel platforms to accelerate fingerprint matching process by using MCC: (1) a multi-core server, and (2) a Xeon Phi coprocessor. Our proposal is based on heaps as auxiliary structure to process the global similarity of MCC. As heap-based algorithms are exhaustive (all the elements are accessed), we also explored the use an indexing algorithm to avoid comparing the query against all the fingerprints of the database. Experimental results show an improvement up to 97.15x of speed-up, which is competitive compared to other state-of-the-art algorithms in GPU and FPGA. To the best of our knowledge, this is the first work for fingerprint identification using a Xeon Phi coprocessor.Instituto de Investigación en Informátic

    Inequality in mortality in pre-industrial Southern Europe during an epidemic episode : socio-economic determinants (eighteenth - nineteenth centuries Spain)

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    The objective of this study is to gain more comprehensive knowledge about social inequality in mortality in pre-industrial periods. With this aim, we have reconstructed the life courses of the inhabitants of the town of Vera in south-east Spain for the period 1797-1812 in order to estimate the influence of socio-economic status on ordinary and extraordinary mortality, given that, during this period, the town suffered from several epidemic outbreaks of yellow fever. As a result of these outbreaks, around a quarter of the town's population died. The results obtained indicate social inequality in mortality at least from the end of the eighteenth century. Although the differences are higher in mortality caused by non-infectious diseases or ill-defined causes, the coefficients also show a certain social gradient in mortality derived from infectious diseases. However, with respect to this latter type of mortality, the place of residence - seems to have a greater influence on the chances of survival than socio-economic status
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