1,749 research outputs found

    Transplacental transmission of field and rescued strains of BTV-2 and BTV-8 in experimentally infected sheep

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    Transplacental transmission of bluetongue virus has been shown previously for the North European strain of serotype 8 (BTV-8) and for tissue culture or chicken egg-adapted vaccine strains but not for field strains of other serotypes. In this study, pregnant ewes (6 per group) were inoculated with either field or rescued strains of BTV-2 and BTV-8 in order to determine the ability of these viruses to cross the placental barrier. The field BTV-2 and BTV-8 strains was passaged once in Culicoides KC cells and once in mammalian cells. All virus inoculated sheep became infected and seroconverted against the different BTV strains used in this study. BTV RNA was detectable in the blood of all but two ewes for over 28 days but infectious virus could only be detected in the blood for a much shorter period. Interestingly, transplacental transmission of BTV-2 (both field and rescued strains) was demonstrated at high efficiency (6 out of 13 lambs born to BTV-2 infected ewes) while only 1 lamb of 12 born to BTV-8 infected ewes showed evidence of in utero infection. In addition, evidence for horizontal transmission of BTV-2 between ewes was observed. As expected, the parental BTV-2 and BTV-8 viruses and the viruses rescued by reverse genetics showed very similar properties to each other. This study showed, for the first time, that transplacental transmission of BTV-2, which had been minimally passaged in cell culture, can occur; hence such transmission might be more frequent than previously thought

    Absolute calibration and beam reconstruction of MITO (a ground-based instrument in the millimetric region)

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    An efficient sky data reconstruction derives from a precise characterization of the observing instrument. Here we describe the reconstruction of performances of a single-pixel 4-band photometer installed at MITO (Millimeter and Infrared Testagrigia Observatory) focal plane. The strategy of differential sky observations at millimeter wavelengths, by scanning the field of view at constant elevation wobbling the subreflector, induces a good knowledge of beam profile and beam-throw amplitude, allowing efficient data recovery. The problems that arise estimating the detectors throughput by drift scanning on planets are shown. Atmospheric transmission, monitored by skydip technique, is considered for deriving final responsivities for the 4 channels using planets as primary calibrators.Comment: 14 pages, 6 fiugres, accepted for pubblication by New Astronomy (25 March

    Cosmic Microwave Background Temperature at Galaxy Clusters

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    We have deduced the cosmic microwave background (CMB) temperature in the Coma cluster (A1656, z=0.0231z=0.0231), and in A2163 (z=0.203z=0.203) from spectral measurements of the Sunyaev-Zel'dovich (SZ) effect over four passbands at radio and microwave frequencies. The resulting temperatures at these redshifts are TComa=2.7890.065+0.080T_{Coma} = 2.789^{+0.080}_{-0.065} K and TA2163=3.3770.102+0.101T_{A2163} = 3.377^{+0.101}_{-0.102} K, respectively. These values confirm the expected relation T(z)=T0(1+z)T(z)=T_{0}(1+z), where T0=2.725±0.002T_{0}= 2.725 \pm 0.002 K is the value measured by the COBE/FIRAS experiment. Alternative scaling relations that are conjectured in non-standard cosmologies can be constrained by the data; for example, if T(z)=T0(1+z)1aT(z) = T_{0}(1+z)^{1-a} or T(z)=T0[1+(1+d)z]T(z)=T_{0}[1+(1+d)z], then a=0.160.32+0.34a=-0.16^{+0.34}_{-0.32} and d=0.17±0.36d = 0.17 \pm 0.36 (at 95% confidence). We briefly discuss future prospects for more precise SZ measurements of T(z)T(z) at higher redshifts.Comment: 13 pages, 1 figure, ApJL accepted for publicatio

    Psychiatric profile of motor subtypes of de novo drug-naïve Parkinson's disease patients

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    Background: Parkinson's disease (PD) is a heterogeneous neurodegenerative disorder. It is well established that different motor subtypes of PD evolve with different clinical courses and prognoses. The complete psychiatric profile underlying these different phenotypes since the very early stage of the disease is debated. Aims of the study: We aimed at investigating the psychiatric profile of the three motor subtypes of PD (akinetic-rigid, tremor-dominant, and mixed) in de novo drug-naïve patients with PD. Methods: Sixty-eight patients with PD, divided into 39 akinetic-rigid (AR), seven mixed (MIX), and 22 tremor-dominant (TD) patients underwent a complete assessment of psychiatric, cognitive, and motor symptoms. Results: No significant differences were found among groups. Conclusions: Our results suggest that a differentiation of the psychiatric symptoms associated with specific motor subtypes of PD is not detectable in de novo drug-naïve patients. Previous evidence that emerges later along the disease progression may be a consequence of the dopaminergic and nondopaminergic damage increase

    Triple Experiment Spectrum of the Sunyaev-Zeldovich Effect in the Coma Cluster: H_0

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    The Sunyaev-Zeldovich (SZ) effect was previously measured in the Coma cluster by the Owens Valley Radio Observatory and Millimeter and IR Testa Grigia Observatory experiments and recently also with the Wilkinson Microwave Anisotropy Probe satellite. We assess the consistency of these results and their implications on the feasibility of high-frequency SZ work with ground-based telescopes. The unique data set from the combined measurements at six frequency bands is jointly analyzed, resulting in a best-fit value for the Thomson optical depth at the cluster center, tau_{0}=(5.35 \pm 0.67) 10^{-3}. The combined X-ray and SZ determined properties of the gas are used to determine the Hubble constant. For isothermal gas with a \beta density profile we derive H_0 = 84 \pm 26 km/(s\cdot Mpc); the (1\sigma) error includes only observational SZ and X-ray uncertainties.Comment: 11 pages, 1 figur

    Innovative Configuration for a Far Infrared Space Interferometer

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    In the last ten years many proposals and studies have been advanced for a far-IR kilometer baseline interferometer. This paper shows the results of FISICA (Far Infrared Space Interferometer Critical Assessment), an FP7 program of the European Community. In particular, we focus on an innovative strategy to cover the plane of observation with a minimal propellant consumption. Results of some numerical simulations, carried out for a three-booms configuration, are provided

    Planck pre-launch status: HFI beam expectations from the optical optimisation of the focal plane

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    Planck is a European Space Agency (ESA) satellite, launched in May 2009, which will map the cosmic microwave background anisotropies in intensity and polarisation with unprecedented detail and sensitivity. It will also provide full-sky maps of astrophysical foregrounds. An accurate knowledge of the telescope beam patterns is an essential element for a correct analysis of the acquired astrophysical data. We present a detailed description of the optical design of the High Frequency Instrument (HFI) together with some of the optical performances measured during the calibration campaigns. We report on the evolution of the knowledge of the pre-launch HFI beam patterns when coupled to ideal telescope elements, and on their significance for the HFI data analysis procedure

    Detection of the tSZ effect with the NIKA camera

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    We present the first detection of the thermal Sunyaev-Zel'dovich (tSZ) effect from a cluster of galaxies performed with a KIDs (Kinetic Inductance Detectors) based instrument. The tSZ effect is a distortion of the black body CMB (Cosmic Microwave Background) spectrum produced by the inverse Compton interaction of CMB photons with the hot electrons of the ionized intra-cluster medium. The massive, intermediate redshift cluster RX J1347.5-1145 has been observed using NIKA (New IRAM KIDs arrays), a dual-band (140 and 240 GHz) mm-wave imaging camera, which exploits two arrays of hundreds of KIDs: the resonant frequencies of the superconducting resonators are shifted by mm-wave photons absorption. This tSZ cluster observation demonstrates the potential of the next generation NIKA2 instrument, being developed for the 30m telescope of IRAM, at Pico Veleta (Spain). NIKA2 will have 1000 detectors at 140GHz and 2x2000 detectors at 240GHz, providing in that band also a measurement of the linear polarization. NIKA2 will be commissioned in 2015.Comment: SF2A Proceedings 201

    The NIKA instrument: results and perspectives towards a permanent KID based camera for the Pico Veleta observatory

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    The New IRAM KIDs Array (NIKA) is a pathfinder instrument devoted to millimetric astronomy. In 2009 it was the first multiplexed KID camera on the sky; currently it is installed at the focal plane of the IRAM 30-meters telescope at Pico Veleta (Spain). We present preliminary data from the last observational run and the ongoing developments devoted to the next NIKA-2 kilopixels camera, to be commissioned in 2015. We also report on the latest laboratory measurements, and recent improvements in detector cosmetics and read-out electronics. Furthermore, we describe a new acquisition strategy allowing us to improve the photometric accuracy, and the related automatic tuning procedure.Comment: 24th International Symposium on Space Terahertz Technology, ISSTT 2013, April 8 to 10, 2013, Groningen, the Netherland
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