7,386 research outputs found

    New objects in old structures: The Iron Age hoard of the Palacio III megalithic funerary complex (Almadén de la Plata, Seville, Spain)

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    Cultural contact, exchange and interaction feature high in the list of challenging topics of current research on European Prehistory. Not far off is the issue of the changing role of monuments in the making and maintaining of key cultural devices such as memory and identity. Addressing both these highly-debated issues from a science-based perspective, in this paper we look at an unusual case study set in southern Iberia and illustrate how these archaeological questions can benefit from robust materials-science approaches.We present the contextual, morphological and analytical study of an exceptional Early Iron Age hoard composed of a number of different (and mostly exotic) materials such as amber, quartz, silver and ceramic. This hoard, found under the fallen orthostat of a megalithic structure built at least 2000 years earlier, throws new light on long-distance exchange networks and the effect they could have had on the cultural identities and social relations of local Iberian Early Iron Age communities. Moreover, the archaeometric study reveals how diverse and distant the sources of these item are (Northern Europe to Eastern and Western Mediterranean raw materials, as well as local and eastern technologies), therefore raising questions concerning the social mechanisms used to establish change and resistance in contexts of colonial encounter

    Solution blow spinning and obtaining submicrometric fibers of different polymers

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    Thermoplastic polymers with potential biomedical and electrical applications such as polyethyleneoxide, PEO, polyvinylidene fluoride, PVDF, polyethylene-co-vinyl acetate, EVA were prepared bysolution blow spinning, SBS, looking for the best processing conditions to obtain submicrometricfibers with highest homogeneity in terms of morphology. Fabrication was carried out by a commercialairbrush and a home-made automatic SBS device. The aim of this work was to optimize the SBSprocess for each of the polymer systems to get films in the form of mats formed by submicrometricfibers. In particular, the pressure of the ejecting gas, the feed rate of the polymer solution and theworking distance was considered as the final influencing parameters on the materials morphology.SEM was used as the main technique to evaluate the effect of the processing conditions on the finalmorphology. The different morphologies obtained showed a directly dependence of between themand the processing conditions. Gas pressure, feed rate and working distance have a great influencein the fiber production, fiber diameter, and fiber diameter distribution.Authors gratefully acknowledge financial support from the Projects MAT2014-59116-C2 (Ministerio de Economía y Competitividad); 2012/00130/004 (Fondos de Investigación de Fco. Javier González Benito, política de reinversión de costes generales, Universidad Carlos III de Madrid) and 2011/00287/002 (Acción Estratégica en Materiales Compuestos Poliméricos e Interfases, Universidad Carlos III de Madrid)

    Electromagnetic waves in a wormhole geometry

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    We investigate the propagation of electromagnetic waves through a static wormhole. It is shown that the problem can be reduced to a one-dimensional Schr\"odinger-like equation with a barrier-type potential. Using numerical methods, we calculate the transmission coefficient as a function of the energy. We also discuss the polarization of the outgoing radiation due to this gravitational scattering.Comment: LaTex file, 5 pages, 2 figures, one reference added, accepted for publication in PR

    Guiding-center dynamics of vortex dipoles in Bose-Einstein condensates

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    A quantized vortex dipole is the simplest vortex molecule, comprising two counter-circulating vortex lines in a superfluid. Although vortex dipoles are endemic in two-dimensional superfluids, the precise details of their dynamics have remained largely unexplored. We present here several striking observations of vortex dipoles in dilute-gas Bose-Einstein condensates, and develop a vortex-particle model that generates vortex line trajectories that are in good agreement with the experimental data. Interestingly, these diverse trajectories exhibit essentially identical quasi-periodic behavior, in which the vortex lines undergo stable epicyclic orbits.Comment: 4 pages, 2 figure

    No AGN evidence in NGC 1614 from deep radio VLBI observations

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    We present deep dual-band 5.0- and 8.4-GHz European VLBI Network (EVN) observations of NGC 1614, a local luminous infrared galaxy with a powerful circumnuclear starburst ring, and whose nuclear engine origin is still controversial. We aim at detecting and characterizing compact radio structures both in the nuclear region and in the circumnuclear ring. We do not find any compact source in the central 200 pc region, setting a very tight 5s upper limit of 3.7 × 1036 and 5.8 × 1036 erg s-1, at 5.0 and 8.4 GHz, respectively. However, we report a clear detection at both frequencies of a compact structure in the circumnuclear ring, 190 pc to the north of the nucleus, whose luminosity and spectral index are compatible with a core-collapse supernova, giving support to the high star formation rate in the ring. Our result favours the pure starburst scenario, even for the nucleus of NGC 1614, and shows the importance of radio VLBI (very long baseline interferometry) observations when dealing with the obscured environments of dusty galaxies

    The effects of weather and climate change on dengue

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    There is much uncertainty about the future impact of climate change on vector-borne diseases. Such uncertainty reflects the difficulties in modelling the complex interactions between disease, climatic and socioeconomic determinants. We used a comprehensive panel dataset from Mexico covering 23 years of province-specific dengue reports across nine climatic regions to estimate the impact of weather on dengue, accounting for the effects of non-climatic factors

    The Core-Collapse Supernova Rate in Arp299 Revisited

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    We present a study of the CCSN rate in nuclei A and B1 of the luminous infrared galaxy Arp299, based on 11 years of Very Large Array monitoring of their radio emission at 8.4 GHz. Significant variations in the nuclear radio flux density can be used to identify the CCSN activity in the absence of high-resolution very long baseline interferometry observations. In the case of the B1-nucleus, the small variations in its measured diffuse radio emission are below the fluxes expected from radio supernovae, thus making it well-suited to detect RSNe through flux density variability. In fact, we find strong evidence for at least three RSNe this way, which results in a lower limit for the CCSN rate of 0.28 +/- 0.16 per year. In the A-nucleus, we did not detect any significant variability and found a SN detection threshold luminosity which allows only the detection of the most luminous RSNe known. Our method is basically blind to normal CCSN explosions occurring within the A-nucleus, which result in too small variations in the nuclear flux density, remaining diluted by the strong diffuse emission of the nucleus itself. Additionally, we have attempted to find near-infrared counterparts for the earlier reported RSNe in the Arp299 nucleus A, by comparing NIR adaptive optics images from the Gemini-N telescope with contemporaneous observations from the European VLBI Network. However, we were not able to detect NIR counterparts for the reported radio SNe within the innermost regions of nucleus A. While our NIR observations were sensitive to typical CCSNe at 300 mas from the centre of the nucleus A, suffering from extinction up to A_v~15 mag, they were not sensitive to such highly obscured SNe within the innermost nuclear regions where most of the EVN sources were detected. (abridged)Comment: 12 pages, 4 figures and 7 tables. Accepted for publication in MNRA

    Molecular gas at supernova local environments unveiled by EDGE

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    CO observations allow estimations of the gas content of molecular clouds, which trace the reservoir of cold gas fuelling star formation, as well as to determine extinction via H2_2 column density, N(H2_2). Here, we studied millimetric and optical properties at 26 supernovae (SNe) locations of different types in a sample of 23 nearby galaxies by combining molecular 12^{12}C16^{16}O (J = 1 \rightarrow 0) resolved maps from the EDGE survey and optical Integral Field Spectroscopy from the CALIFA survey. We found an even clearer separation between type II and type Ibc SNe in terms of molecular gas than what we found in the optical using Hα\alpha emission as a proxy for current SF rate, which reinforces the fact that SNe Ibc are more associated with SF-environments. While AV_V at SN locations is similar for SNe II and SNe Ibc, and higher compared to SNe Ia, N(H2_2) is significantly higher for SNe Ibc than for SNe II and SNe Ia. When compared to alternative extinction estimations directly from SN photometry and spectroscopy, we find that our SNe Ibc have also redder color excess but showed standard Na I D absorption pseudo-equivalent widths (\sim1 \AA). In some cases we find no extinction when estimated from the environment, but high amounts of extinction when measured from SN observations, which suggests that circumstellar material or dust sublimation may be playing a role. This work serves as a benchmark for future studies combining last generation millimeter and optical IFS instruments to reveal the local environmental properties of extragalactic SNe.Comment: MNRAS accepted, 17 pages, 8 Figures, 4 Table

    A functional IL1RL1 variant regulates corticosteroid-induced sST2 expression in ulcerative colitis

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    Indexación: Web of Science; Scopus.The ST2/IL33 signalling pathway has been associated with ulcerative colitis (UC). ST2, encoded by the IL1RL1 gene, is expressed as both a membrane-anchored receptor (ST2L) activated by IL33 and as a soluble receptor (sST2) with anti-inflammatory properties. In UC patients, sST2 is further increased by corticosteroid treatment; however, the glucocorticoid-mediated molecular regulation remains unknown. We therefore tested whether genetic variants in the IL1RL1 distal promoter are involved in UC and affect glucocorticoid-mediated ST2 expression. Serum ST2 levels and genetic variants in the IL1RL1 distal promoter were examined by ELISA and PCR sequencing in UC patients receiving corticosteroids. Glucocorticoid-mediated ST2 production was evaluated in intestinal mucosa cultures. Molecular regulation of glucocorticoid-mediated ST2 was assessed by RT-qPCR, ChIP assay and luciferase reporter assay. Dexamethasone effect on ST2 transcript expression was analyzed in leukocytes and related to IL1RL1 variants. Sequencing of a distal IL1RL1 promoter region demonstrated that SNPs rs6543115(C) and rs6543116(A) are associated with increased sST2 in UC patients on corticosteroids. Dexamethasone up-regulated sST2 transcription through interaction with the glucocorticoid-response element (GRE) carrying rs6543115(C) variant. Our data indicate that IL1RL1 SNPs rs6543115(C) confer susceptibility to UC and is contained in the GRE, which may modulate glucocorticoid-induced sST2 expression.https://www.nature.com/articles/s41598-017-10465-

    Life Project for Adolescents: A Concept Analysis

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    It is essential to identify protective factors during adolescence due to its high incidence on risk behaviors. One of these factors is to have a life project that influences adolescent decision-making. The concept of life project has mainly been linked to teen pregnancy, depression and suicide; however, some authors agree that the concept is not clearly defined. Therefore, the objective of this paper is to define the concept of adolescent life project, using the methodology developed by Walker and Avant for concept analysis. The following steps were followed are: select a concept, determining the purpose of analysis, identifying all uses of the concept, determining the defining attributes, identifying a model, a borderline and a contrary cases, identifying history and consequences of the concept, and finally defining empirical referents. After the analysis, the final definition of the concept of adolescent life project includes the set of desires, future plans and actions necessary to accomplish it that influence the adolescent decisions. Knowing the importance of this concept when working with adolescents may guide development more effective interventions
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