369 research outputs found

    Environments of a sample of AzTEC submillimetre galaxies in the COSMOS field

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    Aims. Submillimetre galaxies (SMGs) are bright sources at submillimetre wavelengths (F-850 mu m>2-5 mJy). Made up of mostly of high-z galaxies (z>1), SMGs are amongst the most luminous dusty galaxies in the Universe. These galaxies are thought to be the progenitors of the massive elliptical galaxies in the local Universe and to reside in massive haloes at early epochs. Studying their environments and clustering strength is thus important to put these galaxies in a cosmological context.Methods. We present an environmental study of a sample of 116 SMGs in 96 ALMA observation fields, which were initially discovered with the AzTEC camera on ASTE and identified with high-resolution 1.25 mm ALMA imaging within the COSMOS survey field, having either spectroscopic or unambiguous photometric redshift. We analysed their environments making use of the latest release of the COSMOS photometric catalogue, COSMOS2015, a catalogue that contains precise photometric redshifts for more than half a million objects over the 2 deg(2) COSMOS field. We searched for dense galaxy environments computing the so-called overdensity parameter as a function of distance within a radius of 5 from the SMG. We validated this approach spectroscopically for those SMGs for which spectroscopic redshift is available. As an additional test, we searched for extended X-ray emission as a proxy for the hot intracluster medium, performing an X-ray stacking analysis in the 0.5-2 keV band with a 32 '' aperture and our SMG position using all available XMM-Newton and Chandra X-ray observations of the COSMOS field.Results. We find that 27% (31 out of 116) of the SMGs in our sample are located in a galactic dense environment; a fraction that is similar to previous studies. The spectroscopic redshift is known for 15 of these 31 sources, thus this photometric approach is tested using spectroscopy. We are able to confirm that 7 out of 15 SMGs lie in high-density peaks. However, the search for associated extended X-ray emission via an X-ray stacking analysis leads to a detection that is not statistically significant.Peer reviewe

    OPTICAL SPECTROSCOPIC OBSERVATIONS OF GAMMA-RAY BLAZAR CANDIDATES. VI. FURTHER OBSERVATIONS FROM TNG, WHT, OAN, SOAR, AND MAGELLAN TELESCOPES

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    Indexación: Web of ScienceBlazars, one of the most extreme classes of active galaxies, constitute so far the largest known population of.-ray sources, and their number is continuously growing in the Fermi catalogs. However, in the latest release of the Fermi catalog there is still a large fraction of sources that are classified as blazar candidates of uncertain type (BCUs) for which optical spectroscopic observations are necessary to confirm their nature and their associations. In addition, about one-third of the gamma-ray point sources listed in the Third Fermi-LAT Source Catalog (3FGL) are still unassociated and lacking an assigned lower-energy counterpart. Since 2012 we have been carrying out an optical spectroscopic campaign to observe blazar candidates to confirm their nature. In this paper, the sixth of the series, we present optical spectroscopic observations for 30 gamma-ray blazar candidates from different observing programs we carried out with the Telescopio Nazionale Galileo, William Herschel Telescope, Observatorio Astronomico Nacional, Southern Astrophysical Research Telescope, and Magellan. Telescopes. We found that 21 out of 30 sources investigated are BL Lac objects, while the remaining targets are classified as flat-spectrum radio quasars showing the typical broad emission lines of normal quasi-stellar objects. We conclude that our selection of gamma-ray blazar. candidates based on their multifrequency properties continues to be a successful way to discover potential low-energy counterparts of the Fermi. unidentified gamma-ray sources and to confirm the nature of BCUs.http://iopscience.iop.org/article/10.3847/0004-6256/151/4/95/met

    AGT haplotype in ITGA4 gene is related to antibody-mediated rejection in heart transplant patients

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    [Abstract] Introduction. One of the main problems involved in heart transplantation (HT) is antibody-mediated rejection (AMR). Many aspects of AMR are still unresolved, including its etiology, diagnosis and treatment. In this project, we hypothesize that variants in genes involved in B-cell biology in HT patients can yield diagnostic and prognostic information about AMR. Methods. Genetic variants in 61 genes related to B-cell biology were analyzed by next generation sequencing in 46 HT patients, 23 with and 23 without AMR. Results. We identified 3 single nucleotide polymorphisms in ITGA4 gene (c.1845G>A, c.2633A>G, and c.2883C>T) that conformed the haplotype AGT-ITGA4. This haplotype is associated with the development of AMR. Moreover, AMR patients with the haplotype AGT-ITGA4 present lower levels of integrin α-4 in serum samples compared to the reference GAC haplotype in control patients. Conclusion. We can conclude that polymorphisms in genes related to the biology of B-cells could have an important role in the development of AMR. In fact, the AGT haplotype in ITGA4 gene could potentially increase the risk of AMR.Instituto de Salud Carlos III; PI13/0217

    Analysis of multiple single nucleotide polymorphisms closely positioned in the ovine PRNP gene using linear fluorescent probes and melting curve analysis

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    <p>Abstract</p> <p>Background</p> <p>Resistance and susceptibility to scrapie has been associated with single nucleotide polymorphisms located within codons 136, 154 and 171 of the ovine prion protein gene (<it>PRNP</it>). Dual-labelled HyBeacon probes were developed to analyse single and clustered polymorphisms within these and neighbouring codons.</p> <p>Methods</p> <p>Extracted DNAs and unpurified blood samples were genotyped with respect to polymorphisms in <it>PRNP </it>codons 136, 141, 154 and 171. PCR amplicons were investigated using a LightTyper instrument, measuring the stability of probe/target hybridisation through peak melting temperatures and determining the sequence of nucleotides at polymorphic sites.</p> <p>Results</p> <p>The performance of HyBeacon assays was evaluated in a validation study comparing genotypes with those obtained using a primer extension assay (Sequenom MassEXTEND) analysed on a MALDI-ToF mass spectrometer. Over 12,000 sheep samples were successfully genotyped, reliably detecting A<sup>136</sup>, V<sup>136</sup>, T<sup>136</sup>, T<sup>137</sup>, L<sup>141</sup>, F<sup>141 </sup>R<sup>154</sup>, H<sup>154</sup>, L<sup>168</sup>, R<sup>171</sup>, Q<sup>171</sup>, H<sup>171 </sup>and K<sup>171 </sup>sequence variants using only 4 HyBeacon probes.</p> <p>Conclusion</p> <p>HyBeacon assays provide an extremely robust and accurate method for the analysis of single and clustered <it>PRNP </it>polymorphisms in a high-throughput format. The flexibility of the diagnostic tests ensures that samples are correctly genotyped even in the presence of additional sequence variations that flank the polymorphisms of interest. Such sequence variations may also be neutralised using universal bases such as 5-nitroindole if required.</p

    Dark matter line searches with the Cherenkov Telescope Array

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    Monochromatic gamma-ray signals constitute a potential smoking gun signature for annihilating or decaying dark matter particles that could relatively easily be distinguished from astrophysical or instrumental backgrounds. We provide an updated assessment of the sensitivity of the Cherenkov Telescope Array (CTA) to such signals, based on observations of the Galactic centre region as well as of selected dwarf spheroidal galaxies. We find that current limits and detection prospects for dark matter masses above 300 GeV will be significantly improved, by up to an order of magnitude in the multi-TeV range. This demonstrates that CTA will set a new standard for gamma-ray astronomy also in this respect, as the world's largest and most sensitive high-energy gamma-ray observatory, in particular due to its exquisite energy resolution at TeV energies and the adopted observational strategy focussing on regions with large dark matter densities. Throughout our analysis, we use up-to-date instrument response functions, and we thoroughly model the effect of instrumental systematic uncertainties in our statistical treatment. We further present results for other potential signatures with sharp spectral features, e.g. box-shaped spectra, that would likewise very clearly point to a particle dark matter origin

    Effectiveness of rotavirus vaccination in Spain

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    With the aim of determining rotavirus vaccine effectiveness (RVVE) in Spain, from Oct-2008/Jun-2009, 467 consecutive children below 2 years old with acute gastroenteritis (AGE) were recruited using a pediatric research network (ReGALIP-www.regalip.org) that includes primary, emergency and hospital care settings. Of 467 enrolled children, 32.3% were rotavirus positive and 35.0% had received at least one dose of any rotavirus vaccine. RRVE to prevent any episode of rotavirus AGE was 91.5% (95% CI: 83.7%-95.6%). RVVE to prevent hospitalization by rotavirus AGE was 95.6% (85.6-98.6%). No differences in RVVE were found regarding the vaccine used. Rotavirus vaccines have showed an outstanding effectiveness in Spain

    Azithromycin to Prevent Pertussis in Household Contacts, Catalonia and Navarre, Spain, 2012-2013

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    We retrospectively assessed the effectiveness of azithromycin in preventing transmission of pertussis to a patient's household contacts. We also considered the duration between symptom onset in the primary patient and azithromycin administration. We categorized contacts into 4 groups: those treated within 21 days after illness onset in the primary patient. We studied 476 primary index patients and their 1,975 household contacts, of whom 4.5% were later identified as having pertussis. When contacts started chemoprophylaxis within 14 days after primary patient's symptom onset was less effective. We recommend that contacts of persons with pertussis begin chemoprophylaxis within <14 days after primary patient's symptom onset

    Efectos de la suplementación con microminerales en indicadores de producción y su residualidad en sangre, heces y orina de alpacas (Lama lama) en pastoreo.

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    Con el objetivo de analizar el efecto del nivel de suplemento de microminerales adicionales a la dieta sobre las variables alzada peso y diámetro de la fibra de alpacas, se evaluó la aplicación de tres dosis de selenio y zinc (0,0; 1,0 y 1,5 cc), bajo un (DCA) en arreglo factorial (3 x 2) + (3 x 2). Los resultados mostraron diferencias estadísticas para tratamientos: dosis de selenio, edades, dosis de zinc, edades y para la interacción zinc por edades (Se1E2 con 74,33 kg a los 90 días para alzada a la cruz, Zn1E2 con un promedio de 91,33 cm). La longitud de la fibra los tratamientos Se1E1 y Se1E2 con promedio de 3 cm. Para el diámetro de la fibra los tratamientos 1 (Se0E1) y tratamiento Se1E1 del grupo 1 y los tratamientos Zn0E2 y Zn1E1 del grupo 2 mostraron mejor calidad de la fibra (P &lt; 0,05), con promedios de 28 micras. Se confirmó un efecto beneficioso en el peso vivo, calidad de la fibra en animales maduros de la suplementación con los microelementos Se y Zn, que mejoró las características fenotípicas de producción como el peso vivo, aunque manifestó residualidad en la orina de los animales de 3 a 5 años de edad.Effects of Supplementation with Microminerals on Production Indicators and Blood, Feces, and Urine Traces of Grazing alpaca (Lama lama) ABSTRACTIn this area was applied three doses of selenium and zinc (0.0; 1.0 and 1.5 cc), under a (DCA) in factorial arrangement (3 x 2) + (3 x 2) in order to analyze the effect of the level of additional mineral supplement micro (Selenium, Zinc) to the diet on the raised variables, weight and fiber diameter of alpacas. Results revealed statistical differences for treatment: selenium doses, age, Zinc doses, Zinc interaction for ages. For this, the treatment 4 (Se1E2) with 74.33 kg to 90 days to cross height (Zn1E2) with 91.33 cm average. The length fiber into treatments 3 (Se1E1) and 4 (Se1E2) with 3 cm average. For fiber diameter on treatments 1 (Se0E1) Treatment 3 (Se1E1) of group 1, treatments 8 (Zn0E2) and 9 (Zn1E1) which group 2 charged better fiber quality with 28 microns average. It was confirmed an beneficial effect on live weight and fiber quality in mature animals for mineral supply with Se and Zn con los microelements, that improved the production phenotypical characteristics like weight, but it was manifested minerals urine residuality in 3-5 years old animals
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