1,133 research outputs found

    Constraining the Observer Angle of the Kilonova AT2017gfo Associated with GW170817: Implications for the Hubble Constant

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    There is a strong degeneracy between the luminosity distance (D L) and the observer viewing angle (θ obs; hereafter viewing angle) of the gravitational wave (GW) source with an electromagnetic counterpart, GW170817. Here, for the first time, we present independent constraints on IMG ALIGN="MIDDLE" ALT="θobs=32.59.7+11.7{θ}_{\mathrm{obs}}={32.5}-{-9.7}^{^\circ +11.7}" SRC="apjab5799ieqn1.gif"/from broadband photometry of the kilonova (kN) AT2017gfo associated with GW170817. These constraints are consistent with independent results presented in the literature using the associated gamma-ray burst GRB 170817A. Combining the constraints on θ obs with the GW data, we find an improvement of 24% on H 0. The observer angle constraints are insensitive to other model parameters, e.g., the ejecta mass, the half-opening angle of the lanthanide-rich region and the temperature. A broad wavelength coverage extending to the near-infrared is helpful to robustly constrain θ obs. While the improvement on H 0 presented here is smaller than the one from high angular resolution imaging of the radio counterpart of GW170817, kN observations are significantly more feasible at the typical distances of such events from current and future LIGO-Virgo collaboration observing runs (D L ∼ 100 Mpc). Our results are insensitive to the assumption of the peculiar velocity of the kN host galaxy. © 2020. The American Astronomical Society

    Floating stones off El Hierro, Canary Islands: xenoliths of pre-island sedimentary origin in the early products of the October 2011 eruption

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    The eruption that started off the south coast of El Hierro, Canary Islands, in October 2011 has emitted intriguing eruption products found floating in the sea. These specimens appeared as floating volcanic "bombs" that have in the meantime been termed "restingolites" (after the close-by village of La Restinga) and exhibit cores of white and porous pumice-like material. Currently the nature and origin of these "floating stones" is vigorously debated among researchers, with important implications for the interpretation of the hazard potential of the ongoing eruption. The "restingolites" have been proposed to be either (i) juvenile high-silica magma (e.g. rhyolite), (ii) remelted magmatic material (trachyte), (iii) altered volcanic rock, or (iv) reheated hyaloclastites or zeolite from the submarine slopes of El Hierro. Here, we provide evidence that supports yet a different conclusion. We have collected and analysed the structure and composition of samples and compared the results to previous work on similar rocks found in the archipelago. Based on their high silica content, the lack of igneous trace element signatures, and the presence of remnant quartz crystals, jasper fragments and carbonate relicts, we conclude that "restingolites" are in fact xenoliths from pre-island sedimentary rocks that were picked up and heated by the ascending magma causing them to partially melt and vesiculate. They hence represent messengers from depth that help us to understand the interaction between ascending magma and crustal lithologies in the Canary Islands as well as in similar Atlantic islands that rest on sediment/covered ocean crust (e.g. Cape Verdes, Azores). The occurrence of these "restingolites" does therefore not indicate the presence of an explosive high-silica magma that is involved in the ongoing eruption

    Lanthanides in granulometric fractions of Mediterranean soils. Can they be used as fingerprints of provenance?

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    Highlights Are lanthanides from fine sand and clay genetically related to the geological materials? Lanthanide concentrations of fine sand and clay fit chronofunctions Pearson's r of lanthanide couples decreases when separation increases in the periodic table Free forms of clay are scavengers of lanthanides and concentrate HREE and ceriumSample preparation and chemical analysis were conducted by Emma Humphreys-Williams and Stanislav Strekopytov (Imaging and Analysis Centre, Natural History Museum, London, UK). This work was supported by a grant from Ministerio de Economía, Industria y Competitividad de España (‘Tipologías de Suelos Mediterráneos versus Cuarzo. En la frontera del conocimiento edafogenético’; Ref. CGL2016-80308-P). The authors thank Professor Margaret A. Oliver, an anonymous editor and two anonymous reviewers for helpful comments and suggestions that improved the final manuscript. We also thank Robert Abrahams (Bsc) for revising the English language.There is geochemical interest in the lanthanides because they behave like a group that is closely related to the parent materials during surface processes, although they also undergo fractionation as a result of supergene dynamics. We analysed lanthanide concentrations (ICPms) in the granulometric fractions fine sand, clay and free forms of clay (FFclay‐CDB and FFclay‐Ox: extracted with citrate‐dithionite‐sodium bicarbonate and with ammonium oxalate, respectively) from a soil chronosequence of Mediterranean soils. There was a relative enrichment of heavy rare earth elements (HREE) in the clay fraction and its free forms with respect to fine sand. The clay free forms behaved as scavengers of lanthanides, and oxidative scavenging of cerium (Ce) in FFclay‐CDB was also detected. Lanthanide concentrations (lanthanum to gadolinium in fine sand; terbium to lutetium in clay) varied with soil age, and chronofunctions were established. There was a strong positive collinearity between most of the lanthanide concentrations. Furthermore, the value of the correlation index (Pearson's r ) of the concentrations between couples of lanthanides (r CLC) decreased significantly with increasing separation between the elements in the periodic table; this has never been described in soils. Several geochemical properties and indices in the fine sand and clay soil fractions and in the geological materials of the Guadalquivir catchment showed, on the one hand, a genetic relation between them all, enabling the lanthanides to be used as fingerprints of provenance; on the other hand, fractionation between fine sand and clay showed these are actively involved in soil lanthanide dynamics.Secretaría de Estado de Investigación, Desarrollo e Innovación. Grant Number: CGL2016‐80308‐

    Longitudinal analysis on parasite diversity in honeybee colonies: new taxa, high frequency of mixed infections and seasonal patterns of variation

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    To evaluate the influence that parasites have on the losses of Apis mellifera it is essential to monitor their presence in the colonies over time. Here we analysed the occurrence of nosematids, trypanosomatids and neogregarines in five homogeneous colonies for up to 21 months until they collapsed. The study, which combined the use of several molecular markers with the application of a massive parallel sequencing technology, provided valuable insights into the epidemiology of these parasites: (I) it enabled the detection of parasite species rarely reported in honeybees (Nosema thomsoni, Crithidia bombi, Crithidia acanthocephali) and the identification of two novel taxa; (II) it revealed the existence of a high rate of co-infections (80% of the samples harboured more than one parasite species); (III) it uncovered an identical pattern of seasonal variation for nosematids and trypanosomatids, that was different from that of neogregarines; (IV) it showed that there were no significant differences in the fraction of positive samples, nor in the levels of species diversity, between interior and exterior bees; and (V) it unveiled that the variation in the number of parasite species was not directly linked with the failure of the colonies

    The transitional gap transient AT 2018hso: new insights into the luminous red nova phenomenon

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    Context. The absolute magnitudes of luminous red novae (LRNe) are intermediate between those of novae and supernovae (SNe), and show a relatively homogeneous spectro-photometric evolution. Although they were thought to derive from core instabilities in single stars, there is growing support for the idea that they are triggered by binary interaction that possibly ends with the merging of the two stars. Aims. AT 2018hso is a new transient showing transitional properties between those of LRNe and the class of intermediate-luminosity red transients (ILRTs) similar to SN 2008S. Through the detailed analysis of the observed parameters, our study supports that it actually belongs to the LRN class and was likely produced by the coalescence of two massive stars. Methods. We obtained ten months of optical and near-infrared photometric monitoring, and 11 epochs of low-resolution optical spectroscopy of AT 2018hso. We compared its observed properties with those of other ILRTs and LRNe. We also inspected the archival Hubble Space Telescope (HST) images obtained about 15 years ago to constrain the progenitor properties. Results. The light curves of AT 2018hso show a first sharp peak (reddening-corrected M-r = -13.93 mag), followed by a broader and shallower second peak that resembles a plateau in the optical bands. The spectra dramatically change with time. Early-time spectra show prominent Balmer emission lines and a weak [Ca II] doublet, which is usually observed in ILRTs. However, the strong decrease in the continuum temperature, the appearance of narrow metal absorption lines, the great change in the H alpha strength and profile, and the emergence of molecular bands support an LRN classification. The possible detection of a M-I similar to -8 mag source at the position of AT 2018hso in HST archive images is consistent with expectations for a pre-merger massive binary, similar to the precursor of the 2015 LRN in M101. Conclusions. We provide reasonable arguments to support an LRN classification for AT 2018hso. This study reveals growing heterogeneity in the observables of LRNe than has been thought previously, which is a challenge for distinguishing between LRNe and ILRTs. This suggests that the entire evolution of gap transients needs to be monitored to avoid misclassifications

    Petrology and geochemistry of Cardeña-Virgen de La Cabeza pluton (batholith of Los Pedroches)

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    [Resumen] El plutón de Cardeña-Virgen de La Cabeza es uno de los cuerpos intrusivos que integran la unidad granítica del batolito de Los Pedroches. Dentro de este plutón, se ha establecido el emplazamiento sucesivo en el tiempo de: 1) adamellitas biotíticas, 2) granitos biotíticos porfídicos ± cordierita, 3) leucogranitos ± cordierita. Las adamellitas biotíticas muestran localmente paso gradual hacia las facies granodioríticas del batolito. Existe además un importante complejo filoniano que se intruye posteriormente, formado por diques riodacíticos de dirección NO-SE, lamprófidos, aplitas, pegmatitas y filones mineralizados· de cuarzo. Geoquímicamente, la adamellita y el granito biotítico porfídico constituyen una asociación alumino-cafémica de carácter calcoalcalino. Los enclaves anfibólicos (términos cafémicos) poseen carácter metaaluminoso. Los leucogranitos se desvían de la tendencia general definiendo una asociación aluminosa y leucocrática. Los diagramas de variación para elementos mayores, menores, trazas y tierras.raras de adamellitas, granitos biotíticos porfídicos y de granodioritas, rocas, estas últimas, con las que se encuentran íntimamente relacionadas, son compatibles con procesos de diferenciación magmática por cristalización fraccionada a partir de un magma inicial de composición granodiorítica más básico[Abstract] The Cardeña-Virgen de La Cabeza intrusion belongs to the granitic unit of the Los Pedroches batholith. the chronology of the intrusion of the different rocktypes that make up the pluton is as follows: 1) biotitic adamellite, 2) porphyritic, cordierite-bearing, biotitic granite. 3) cordierite bearing leucogranite. The biotitic adamellite locally shows a transition to the granodioritic facies of the batholith. A great amount ofNW-SW oriented dikes with rhyodacitic composition intruded subsequently. Lampophyres, aplites, pegmatites and ore-bearing quartz veins complete the dike complexo Adamellite and biotitic ganite define an aluminous-cafemic association with calcalkaline affinity. The amphibole-bearing enclaves represent the cafemic terms of the series and have a metaaluminous character.The leucogranite deviates from the general trend defining and aluminous, leucocratic association. Variation diagrams for major, minor and trace elements, including REE, of adamallite, porphyritic biotitic granite and granodiorite of the main pluton (which is intimately associated with the Cardeña-Virgen de La Cabeza intrusion) suggest a process of magmatic differentiation through fractional crystallization starting from a slightly more basic granodioritic magma

    The helicase HAGE prevents interferon-a-induced PML expression in ABCB5+ malignant melanoma-initiating cells by promoting the expression of SOCS1

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    The tumour suppressor PML (promyelocytic leukaemia protein) regulates several cellular pathways involving cell growth, apoptosis, differentiation and senescence. PML also has an important role in the regulation of stem cell proliferation and differentiation. Here, we show the involvement of the helicase HAGE in the transcriptional repression of PML expression in ABCB5 + malignant melanoma-initiating cells (ABCB5 + MMICs), a population of cancer stem cells which are responsible for melanoma growth, progression and resistance to drug-based therapy. HAGE prevents PML gene expression by inhibiting the activation of the JAK-STAT (janus kinase-signal transducers and activators of transcription) pathway in a mechanism which implicates the suppressor of cytokine signalling 1 (SOCS1). Knockdown of HAGE led to a significant decrease in SOCS1 protein expression, activation of the JAK-STAT signalling cascade and a consequent increase of PML expression. To confirm that the reduction in SOCS1 expression was dependent on the HAGE helicase activity, we showed that SOCS1, effectively silenced by small interfering RNA, could be rescued by re-introduction of HAGE into cells lacking HAGE. Furthermore, we provide a mechanism by which HAGE promotes SOCS1 mRNA unwinding and protein expression in vitro

    The long-lived Type IIn SN 2015da: Infrared echoes and strong interaction within an extended massive shell star star star

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    In this paper we report the results of the first similar to four years of spectroscopic and photometric monitoring of the Type IIn supernova SN 2015da (also known as PSN J13522411+3941286, or iPTF16tu). The supernova exploded in the nearby spiral galaxy NGC 5337 in a relatively highly extinguished environment. The transient showed prominent narrow Balmer lines in emission at all times and a slow rise to maximum in all bands. In addition, early observations performed by amateur astronomers give a very well-constrained explosion epoch. The observables are consistent with continuous interaction between the supernova ejecta and a dense and extended H-rich circumstellar medium. The presence of such an extended and dense medium is difficult to reconcile with standard stellar evolution models, since the metallicity at the position of SN 2015da seems to be slightly subsolar. Interaction is likely the mechanism powering the light curve, as confirmed by the analysis of the pseudo bolometric light curve, which gives a total radiated energy greater than or similar to 10(51) erg. Modeling the light curve in the context of a supernova shock breakout through a dense circumstellar medium allowed us to infer the mass of the prexisting gas to be similar or equal to 8 M-circle dot, with an extreme mass-loss rate for the progenitor star similar or equal to 0.6 M-circle dot yr(-1), suggesting that most of the circumstellar gas was produced during multiple eruptive events. Near- and mid-infrared observations reveal a fluxexcess in these domains, similar to those observed in SN 2010jl and other interacting transients, likely due to preexisting radiatively heated dust surrounding the supernova. By modeling the infrared excess, we infer a mass greater than or similar to 0.4 x 10(-3) M-circle dot for the dustSpanish MICINN gran

    The genomics of visuospatial neurocognition in obsessive-compulsive disorder: A preliminary GWAS

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    Background: The study of Obsessive-Compulsive Disorder (OCD) genomics has primarily been tackled by Genome-wide association studies (GWAS), which have encountered troubles in identifying replicable single nucleotide polymorphisms (SNPs). Endophenotypes have emerged as a promising avenue of study in trying to elucidate the genomic bases of complex traits such as OCD.Methods: We analyzed the association of SNPs across the whole genome with the construction of visuospatial information and executive performance through four neurocognitive variables assessed by the Rey-Osterrieth Complex Figure Test (ROCFT) in a sample of 133 OCD probands. Analyses were performed at SNP- and genelevel.Results: No SNP reached genome-wide significance, although there was one SNP almost reaching significant association with copy organization (rs60360940; P = 9.98E-08). Suggestive signals were found for the four variables at both SNP- (P < 1E-05) and gene-levels (P < 1E-04). Most of the suggestive signals pointed to genes and genomic regions previously associated with neurological function and neuropsychological traits. Limitations: Our main limitations were the sample size, which was limited to identify associated signals at a genome-wide level, and the composition of the sample, more representative of rather severe OCD cases than a population-based OCD sample with a broad severity spectrum.Conclusions: Our results suggest that studying neurocognitive variables in GWAS would be more informative on the genetic basis of OCD than the classical case/control GWAS, facilitating the genetic characterization of OCD and its different clinical profiles, the development of individualized treatment approaches, and the improvement of prognosis and treatment response
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