563 research outputs found

    A Chandra View Of Nonthermal Emission In The Northwestern Region Of Supernova Remnant RCW 86: Particle Acceleration And Magnetic Fields

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    The shocks of supernova remnants (SNRs) are believed to accelerate particles to cosmic ray (CR) energies. The amplification of the magnetic field due to CRs propagating in the shock region is expected to have an impact on both the emission from the accelerated particle population, as well as the acceleration process itself. Using a 95 ks observation with the Advanced CCD Imaging Spectrometer (ACIS) onboard the Chandra X-ray Observatory, we map and characterize the synchrotron emitting material in the northwestern region of RCW 86. We model spectra from several different regions, filamentary and diffuse alike, where emission appears dominated by synchrotron radiation. The fine spatial resolution of Chandra allows us to obtain accurate emission profiles across 3 different non-thermal rims in this region. The narrow width (l = 10''-30'') of these filaments constrains the minimum magnetic field strength at the post-shock region to be approximately 80 {\mu}G.Comment: 7 pages, 3 figures, submitted for publication at the Astrophysical Journa

    Delayed Emergence from General Anesthesia

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    The incidence of perioperative morbidity associated with varying degrees of untreated thyroid disease is unknown, however major complications have been reported including severe hypotension or cardiac arrest, extreme sensitivity to opioids and anesthetics with prolonged unconsciousness, and myxedema coma. Myxedema coma is a rare and life-threatening illness the outcome of which has not been robustly studied in large numbers, partly due to its low incidence. This case illustrates the differential diagnosis of delayed emergence from general anesthesia and the value of a complete history and physical exam. Although delayed emergence from general anesthesia is not uncommon, recognizing the cause and instituting timely treatment is imperative in conditions where delayed therapy can increase morbidity and mortality

    Sterile Neutrinos, Coherent Scattering and Oscillometry Measurements with Low-temperature Bolometers

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    Coherent neutrino-nucleon scattering offers a unique approach in the search for physics beyond the Standard Model. When used in conjunction with mono-energetic neutrino sources, the technique can be sensitive to the existence of light sterile neutrinos. The ability to utilize such reactions has been limited in the past due to the extremely low energy threshold (10-50 eV) needed for detection. In this paper, we discuss an optimization of cryogenic solid state bolometers that enables reaching extremely low kinetic energy thresholds. We investigate the sensitivity of an array of such detectors to neutrino oscillations to sterile states. A recent analysis of available reactor data appears to favor the existence of such such a sterile neutrino with a mass splitting of Δmsterile21.5|\Delta m_{\rm sterile}|^2 \ge 1.5 eV2^2 and mixing strength of sin22θsterile=0.17±0.08\sin^2{2\theta_{\rm sterile}} = 0.17\pm 0.08 at 95% C.L. An array of such low-threshold detectors would be able to make a definitive statement as to the validity of the interpretation.Comment: 14 pages, 10 figures. Version 2: Temperature dependence on alpha fixed from earlier versio

    Selection of indigenous lactic acid bacteria presenting anti-listerial activity, and their role in reducing the maturation period and assuring the safety of traditional Brazilian cheeses

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    Artisanal raw milk cheeses are highly appreciated dairy products in Brazil and ensuring their microbiological safety has been a great need. This study reports the isolation and characterization of lactic acid bacteria (LAB) strains with anti-listerial activity, and their effects on Listeria monocytogenes during refrigerated shelf-life of soft Minas cheese and ripening of semi-hard Minas cheese. LAB strains (n ¼ 891) isolated from Minas artisanal cheeses (n ¼ 244) were assessed for anti-listerial activity by deferred antagonism assay at 37 C and 7 C. The treatments comprised the production of soft or semi-hard Minas cheeses using raw or pasteurized milk, and including the addition of selected LAB only [Lactobacillus brevis 2-392, Lactobacillus plantarum 1-399 and 4 Enterococcus faecalis (1-37, 2-49, 2-388 and 1-400)], L. monocytogenes only, selected LAB co-inoculated with L. monocytogenes, or without any added cultures. At 37 C, 48.1% of LAB isolates showed anti-listerial capacity and 77.5% maintained activity at 7 C. Selected LAB strains presented a bacteriostatic effect on L. monocytogenes in soft cheese. L. monocytogenes was inactivated during the ripening of semi-hard cheeses by the mix of LAB added. Times to attain a 4 log-reduction of L. monocytogenes were 15 and 21 days for semi-hard cheeses produced with raw and pasteurized milk, respectively. LAB with anti-listerial activity isolated from artisanal Minas cheeses can comprise an additional barrier to L. monocytogenes growth during the refrigerated storage of soft cheese and help shorten the ripening period of semi-hard cheeses aged at ambient temperature.The authors thank the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) for financial support (Grants 13/ 20456-9, 14/14891-7, 15/25641-4, 16/21041-5, 16/12406-0 and 16/ 09346-5). Dr. Gonzales-Barron also acknowledges the financial support provided by the Portuguese Foundation for Science and Technology (FCT) through the award of an Investigator Fellowship (IF) in the mode of Development Grants (IF/00570). A.S. Sant'Ana acknowledges the financial support of “Conselho Nacional de Desenvolvimento Científico e Tecnológico” (CNPq) (Grant #302763/ 2014-7) and CAPES (Grant #33003017027P1).info:eu-repo/semantics/publishedVersio

    H1 and H2 control design for polytopic continuous-time Markov jump linear systems with uncertain transition rates.

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    This paper investigates the problems of H1 and H2 state feedback control design for continuous-time Markov jump linear systems. The matrices of each operation mode are supposed to be uncertain, belonging to a polytope, and the transition rate matrix is considered partly known. By appropriately modeling all the uncertain parameters in terms of a multi-simplex domain, new design conditions are proposed, whose main advantage with respect to the existing ones is to allow the use of polynomially parameter-dependent Lyapunov matrices to certify the mean square closed-loop stability. Synthesis conditions are derived in terms of matrix inequalities with a scalar parameter. The conditions, which become LMIs for fixed values of the scalar, can cope with H1 and H2 state feedback control in both mode-independent and modedependent cases. Using polynomial Lyapunov matrices of larger degrees and performing a search for the scalar parameter, less conservative results in terms of guaranteed costs can be obtained through LMI relaxations. Numerical examples illustrate the advantages of the proposed conditions when compared with other techniques from the literature

    Early Salmonella Typhimurium infection in pigs disrupts Microbiome composition and functionality principally at the ileum mucosa

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    [EN] Salmonella is a major foodborne pathogen which successfully infects animal species for human consumption such as swine. The pathogen has a battery of virulence factors which it uses to colonise and persist within the host. The host microbiota may play a role in resistance to, and may also be indirectly responsible from some of the consequences of, Salmonella infection. To investigate this, we used 16S rRNA metagenomic sequencing to determine the changes in the gut microbiota of pigs in response to infection by Salmonella Typhimurium at three locations: ileum mucosa, ileum content and faeces. Early infection (2 days post-infection) impacted on the microbiome diversity at the mucosa, reflected in a decrease in representatives of the generally regarded as desirable genera (i.e., Bifidobacterium and Lactobacillus). Severe damage in the epithelium of the ileum mucosa correlated with an increase in synergistic (with respect to Salmonella infection; Akkermansia) or opportunistically pathogenic bacteria (Citrobacter) and a depletion in anaerobic bacteria (Clostridium spp., Ruminococcus, or Dialliser). Predictive functional analysis, together with metabolomic analysis revealed changes in glucose and lipid metabolism in infected pigs. The observed changes in commensal healthy microbiota, including the growth of synergistic or potentially pathogenic bacteria and depletion of beneficial or competing bacteria, could contribute to the pathogen's ability to colonize the gut successfully. The findings from this study could be used to form the basis for further research aimed at creating intervention strategies to mitigate the effects of Salmonella infectionSIWe want to acknowledge the staff from the Genomics and Animal breeding group at the University of Córdoba for their technical support to carry out this study. This article is based upon work from COST Action FA1401 (PiGutNet), supported by COST (European Cooperation in Science and Technology. This work was supported by the Spanish Ministry of Economy and Competitiveness (AGL2014-54089-R/AGL2017-87415-R). HA was funded by the PiGutNet COST action (FA1401) for a Short-Term Scientific Mission at INRA’s GABI laboratory (Jouy-en- Josas, France). SZL is a postdoctoral researcher supported by the Postdoctoral Trainee Program of the Spanish Ministry of Economy and Competitiveness (FPDI-2013-15619). HA is a postdoctoral researcher supported by the Juan de la Cierva Postdoctoral Trainee Program of the Spanish Ministry of Economy and Competitiveness (FJCI-2014-22877

    Analysis of the low-energy electron-recoil spectrum of the CDMS experiment

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    We report on the analysis of the low-energy electron-recoil spectrum from the CDMS II experiment using data with an exposure of 443.2 kg-days. The analysis provides details on the observed counting rate and possible background sources in the energy range of 2 - 8.5 keV. We find no significant excess in the counting rate above background, and compare this observation to the recent DAMA results. In the framework of a conversion of a dark matter particle into electromagnetic energy, our 90% confidence level upper limit of 0.246 events/kg/day at 3.15 keV is lower than the total rate above background observed by DAMA by 8.9σ\sigma. In absence of any specific particle physics model to provide the scaling in cross section between NaI and Ge, we assume a Z^2 scaling. With this assumption the observed rate in DAMA differs from the upper limit in CDMS by 6.8σ\sigma. Under the conservative assumption that the modulation amplitude is 6% of the total rate we obtain upper limits on the modulation amplitude a factor of ~2 less than observed by DAMA, constraining some possible interpretations of this modulation.Comment: 4 pages, 3 figure

    Characterization of SuperCDMS 1-inch Ge Detectors

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    The newly commissioned SuperCDMS Soudan experiment aims to search for WIMP dark matter with a sensitivity to cross sections of 5×10^(−45)cm^2 and larger (90% CL upper limit). This goal is facilitated by a new set of germanium detectors, 2.5 times more massive than the ones used in the CDMS-II experiment, and with a different athermal phonon sensor layout that eliminates radial degeneracy in position reconstruction of high radius events. We present characterization data on these detectors, as well as improved techniques for correcting position-dependent variations in pulse shape across the detector. These improvements provide surface-event discrimination sufficient for a reach of 5×10^(−45)cm^2
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