122 research outputs found

    Phase-resolved NuSTAR and Swift-XRT Observations of Magnetar 4U 0142+61

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    We present temporal and spectral analysis of simultaneous 0.5-79 keV Swift-XRT and NuSTAR observations of the magnetar 4U 0142+61. The pulse profile changes significantly with photon energy between 3 and 35 keV. The pulse fraction increases with energy, reaching a value of ~20%, similar to that observed in 1E 1841-045 and much lower than the ~80% pulse fraction observed in 1E 2259+586. We do not detect the 55-ks phase modulation reported in previous Suzaku-HXD observations. The phase-averaged spectrum of 4U 0142+61 above 20 keV is dominated by a hard power law with a photon index, Γ\Gamma ~ 0.65, and the spectrum below 20 keV can be described by two blackbodies, a blackbody plus a soft power law, or by a Comptonized blackbody model. We study the full phase-resolved spectra using the electron-positron outflow model of Beloborodov (2013). Our results are consistent with the parameters of the active j-bundle derived from INTEGRAL data by Hascoet et al. (2014). We find that a significant degeneracy appears in the inferred parameters if the footprint of the j-bundle is allowed to be a thin ring instead of a polar cap. The degeneracy is reduced when the footprint is required to be the hot spot inferred from the soft X-ray data.Comment: 14 pages, 8 figures, 4 tables. Accepted for publication in Ap

    The recent neophyte Opuntia aurantiaca Lindl.: distribution and potential invasion in Spain

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    Trabajo presentado en el XVI Optima Meeting (Organization for the Phyto-Taxonomic Investigation of the Mediterranean Area), celebrado en Atenas (Grecia), del 2 al 5 de octubre de 2019The Cactaceae, and especially its most emblematic genus, Opuntia, have become one of the groups of plants with greater invasion potential in Spain. In fact, this area is considered one of the three global hotspots of invasion of cacti, together with South Africa and Australia. In our country, one of the most recently detected species is Opuntia aurantiaca Lindl, a small cactus with an enormous capacity of dispersion by means of cladodes and (sterile) fruits, which are easily detached and adhere to animals, clothes, and footwear. Probably native to the Southern Cone (Argentina and Uruguay), it behaves as a very aggressive invader in Australia and South Africa. In Europe, it only occurs on the Mediterranean coast of the Iberian Peninsula (Catalonia and Valencian Community). In this study, the geographic range of the species is updated at the peninsular level. Firstly detected at the beginning of the last decade in Navajas (Castellón), it has been subsequently observed in other places of the province of Castellón, but also in Valencia, Tarragona and Barcelona. With all occurrence data, its potential distribution is estimated using the algorithm of maximum entropy implemented in the program MaxEnt. Distribution models are built for the current climatic conditions as well as for different scenarios of global warming. Due to its possible invasive nature, it is necessary to eradicate the existing populations at this initial stage. Legislation should consider the prohibition of trade and transport of this plant to avoid new introductions

    Desarrollo, implementación y utilización de modelos para el procesamiento automático de textos

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    El libro recoge ponencias y talleres seleccionados de JALIMI 2005 (Jornadas Argentinas de Lingüística Informática: Modelización e Ingeniería), y está organizado en nueve capítulos y un apéndice. Si bien hay sustantivas diferencias en los enfoques, las metodologías, las propiedades específicas estudiadas y las aplicaciones propuestas o proyectadas, todos los capítulos comunican resultados de investigaciones que pretenden contribuir a alcanzar el objetivo a largo plazo de la Lingüística Informática, a saber: emular en términos cibernéticos la extraordinaria capacidad humana de producir y comprender textos en lengua natural

    The recent neophyte Opuntia aurantiaca (Cactaceae): distribution and potential invasion in the Iberian Peninsula

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    The Cactaceae, and especially its most emblematic genus, Opuntia, is one of the groups of plants with greater invasion potential in the Iberian Peninsula. One of the most recently detected species is Opuntia aurantiaca, a small cactus with an enormous capacity of dispersion. Probably native to Argentina and Uruguay, it behaves as a very aggressive invader in Australia and South Africa. In Europe, it only occurs on the Mediterranean coast of the Iberian Peninsula (Catalonia and Valencian Community). In this study, the geographic range of the species is accurately delineated at the peninsular level. Detected firstly at the beginning of the last decade in Navajas (Castelló Province), it has been subsequently observed in other places of Castelló, but also in Valencia, Tarragona and Barcelona, and since 2017 in Girona. With all gathered occurrence data, the potential distribution of O. aurantiaca is estimated (for the current climatic conditions as well as for different scenarios of global warming). Despite the fact that the species seems to be spreading, maps of potential distribution do not forecast large expansions to other areas of the Iberian Peninsula, both for the present and for the year 2070.This work received financial support from the “Proyecto Intramural Especial, PIE” (grant no. 201630I024) from the CSIC (Spain) and from the “Ajuts a Grups de Recerca Consolidats” (grants nos. 2014-SGR514-GREB and 2017-SGR1116) from the Generalitat de Catalunya (Spain).Abstract Introduction Materials & methods The study species Search for occurrences Ecological niche modelling Results and Discussion Current distribution range of Opuntia aurantiaca in the Iberian Peninsula Present and future potential distribution of Opuntia aurantiaca Acknowledgement

    Inference of Population Structure using Dense Haplotype Data

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    The advent of genome-wide dense variation data provides an opportunity to investigate ancestry in unprecedented detail, but presents new statistical challenges. We propose a novel inference framework that aims to efficiently capture information on population structure provided by patterns of haplotype similarity. Each individual in a sample is considered in turn as a recipient, whose chromosomes are reconstructed using chunks of DNA donated by the other individuals. Results of this “chromosome painting” can be summarized as a “coancestry matrix,” which directly reveals key information about ancestral relationships among individuals. If markers are viewed as independent, we show that this matrix almost completely captures the information used by both standard Principal Components Analysis (PCA) and model-based approaches such as STRUCTURE in a unified manner. Furthermore, when markers are in linkage disequilibrium, the matrix combines information across successive markers to increase the ability to discern fine-scale population structure using PCA. In parallel, we have developed an efficient model-based approach to identify discrete populations using this matrix, which offers advantages over PCA in terms of interpretability and over existing clustering algorithms in terms of speed, number of separable populations, and sensitivity to subtle population structure. We analyse Human Genome Diversity Panel data for 938 individuals and 641,000 markers, and we identify 226 populations reflecting differences on continental, regional, local, and family scales. We present multiple lines of evidence that, while many methods capture similar information among strongly differentiated groups, more subtle population structure in human populations is consistently present at a much finer level than currently available geographic labels and is only captured by the haplotype-based approach. The software used for this article, ChromoPainter and fineSTRUCTURE, is available from http://www.paintmychromosomes.com/

    Nutrimetabolomics: An Integrative Action for Metabolomic Analyses in Human Nutritional Studies

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    The life sciences are currently being transformed by an unprecedented wave of developments in molecular analysis, which include important advances in instrumental analysis as well as biocomputing. In light of the central role played by metabolism in nutrition, metabolomics is rapidly being established as a key analytical tool in human nutritional studies. Consequently, an increasing number of nutritionists integrate metabolomics into their study designs. Within this dynamic landscape, the potential of nutritional metabolomics (nutrimetabolomics) to be translated into a science, which can impact on health policies, still needs to be realized. A key element to reach this goal is the ability of the research community to join, to collectively make the best use of the potential offered by nutritional metabolomics. This article, therefore, provides a methodological description of nutritional metabolomics that reflects on the state‐of‐the‐art techniques used in the laboratories of the Food Biomarker Alliance (funded by the European Joint Programming Initiative "A Healthy Diet for a Healthy Life" (JPI HDHL)) as well as points of reflections to harmonize this field. It is not intended to be exhaustive but rather to present a pragmatic guidance on metabolomic methodologies, providing readers with useful "tips and tricks" along the analytical workflow

    Environmental and Climatic Determinants of Molecular Diversity and Genetic Population Structure in a Coenagrionid Damselfly

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    Identifying environmental factors that structure intraspecific genetic diversity is of interest for both habitat preservation and biodiversity conservation. Recent advances in statistical and geographical genetics make it possible to investigate how environmental factors affect geographic organisation and population structure of molecular genetic diversity within species. Here we present a study on a common and wide ranging insect, the blue tailed damselfly Ischnuraelegans, which has been the target of many ecological and evolutionary studies. We addressed the following questions: (i) Is the population structure affected by longitudinal or latitudinal gradients?; (ii) Do geographic boundaries limit gene flow?; (iii) Does geographic distance affect connectivity and is there a signature of past bottlenecks?; (iv) Is there evidence of a recent range expansion and (vi) what is the effect of geography and climatic factors on population structure? We found low to moderate genetic sub-structuring between populations (mean FST = 0.06, Dest = 0.12), and an effect of longitude, but not latitude, on genetic diversity. No significant effects of geographic boundaries (e.g. water bodies) were found. FST-and Dest-values increased with geographic distance; however, there was no evidence for recent bottlenecks. Finally, we did not detect any molecular signatures of range expansions or an effect of geographic suitability, although local precipitation had a strong effect on genetic differentiation. The population structure of this small insect has probably been shaped by ecological factors that are correlated with longitudinal gradients, geographic distances, and local precipitation. The relatively weak global population structure and high degree of genetic variation within populations suggest that I. elegans has high dispersal ability, which is consistent with this species being an effective and early coloniser of new habitats

    ExoClock Project. III. 450 New Exoplanet Ephemerides from Ground and Space Observations

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    The ExoClock project has been created to increase the efficiency of the Ariel mission. It will achieve this by continuously monitoring and updating the ephemerides of Ariel candidates, in order to produce a consistent catalog of reliable and precise ephemerides. This work presents a homogenous catalog of updated ephemerides for 450 planets, generated by the integration of ∼18,000 data points from multiple sources. These sources include observations from ground-based telescopes (the ExoClock network and the Exoplanet Transit Database), midtime values from the literature, and light curves from space telescopes (Kepler, K2, and TESS). With all the above, we manage to collect observations for half of the postdiscovery years (median), with data that have a median uncertainty less than 1 minute. In comparison with the literature, the ephemerides generated by the project are more precise and less biased. More than 40% of the initial literature ephemerides had to be updated to reach the goals of the project, as they were either of low precision or drifting. Moreover, the integrated approach of the project enables both the monitoring of the majority of the Ariel candidates (95%), and also the identification of missing data. These results highlight the need for continuous monitoring to increase the observing coverage of the candidate planets. Finally, the extended observing coverage of planets allows us to detect trends (transit-timing variations) for a sample of 19 planets. All the products, data, and codes used in this work are open and accessible to the wider scientific community
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