672 research outputs found

    Probing neutrino masses with CMB lensing extraction

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    We evaluate the ability of future cosmic microwave background (CMB) experiments to measure the power spectrum of large scale structure using quadratic estimators of the weak lensing deflection field. We calculate the sensitivity of upcoming CMB experiments such as BICEP, QUaD, BRAIN, ClOVER and PLANCK to the non-zero total neutrino mass M_nu indicated by current neutrino oscillation data. We find that these experiments greatly benefit from lensing extraction techniques, improving their one-sigma sensitivity to M_nu by a factor of order four. The combination of data from PLANCK and the SAMPAN mini-satellite project would lead to sigma(M_nu) = 0.1 eV, while a value as small as sigma(M_nu) = 0.035 eV is within the reach of a space mission based on bolometers with a passively cooled 3-4 m aperture telescope, representative of the most ambitious projects currently under investigation. We show that our results are robust not only considering possible difficulties in subtracting astrophysical foregrounds from the primary CMB signal but also when the minimal cosmological model (Lambda Mixed Dark Matter) is generalized in order to include a possible scalar tilt running, a constant equation of state parameter for the dark energy and/or extra relativistic degrees of freedom.Comment: 13 pages, 4 figures. One new figure and references added. Version accepted for publicatio

    Stability of Hematological Parameters in Woodland Caribou (Rangifer tarandus caribou) Blood Stored at 4°C

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    Eighteen free-ranging female woodland caribou were captured in northern Alberta in January and February 1993. Blood was collected into ethylenediaminetetraacetate (EDTA) tubes which were packaged in coolers containing ice packs, and transported to the laboratory where they arrived within 48 hrs of collection. Complete blood counts (CBC) were performed on five consecutive days to assess the stability of hematological parameters. Average values of hematocrit (HCT), mean cell hemoglobin (MCH), mean cell volume (MCV), red cell distribution width (P-J3W), white blood cell count (WBC), and red blood cell count (RJ3C) remained stable with no statistically significant changes occurring during 5 days of post-collection storage at 4°C. Mean PvBC values exhibited significant differences (p<0.05) between geographic locations. Mean platelet volume (MPV) increased significantly (p<0.001) with storage time, while platelet (PLT) values decreased (p<0.001) over time and were significantly different (p<0.01) between locations. For optimal hematological results, it is recommended that sample analysis be performed within 24 hours of blood collection; however, if caribou blood samples are properly stored at 4°C, useful information may be obtained from stable parameters up to 5 days following collection

    Cosmic Background dipole measurements with Planck-High Frequency Instrument

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    This paper discusses the Cosmic Background (CB) dipoles observations in the framework of the Planck mission. Dipoles observations can be used in three ways: (i) It gives a measurement of the peculiar velocity of our Galaxy which is an important observation in large scale structures formation model. (ii) Measuring the dipole can give unprecedent information on the monopole (that can be in some cases hard to obtain due to large foreground contaminations). (iii) The dipole can be an ideal absolute calibrator, easily detectable in cosmological experiments. Following the last two objectives, the main goal of the work presented here is twofold. First, we study the accuracy of the Planck-HFI calibration using the Cosmic Microwave Background (CMB) dipole measured by COBE as well as the Earth orbital motion dipole. We show that we can reach for HFI, a relative calibration between rings of about 1% and an absolute calibration better than 0.4% for the CMB channels (in the end, the absolute calibration will be limited by the uncertainties on the CMB temperature). We also show that Planck will be able to measure the CMB dipole direction at better than 1.7 arcmin and improve on the amplitude. Second, we investigate the detection of the Cosmic Far-Infrared Background (FIRB) dipole. Measuring this dipole could give a new and independent determination of the FIRB for which a direct determination is quite difficult due to Galactic dust emission contamination. We show that such a detection would require a Galactic dust emission removal at better than 1%, which will be very hard to achieve.Comment: 10 pages, 13 figures, submitted to A&A, uses aa.sty V5.

    Drivers involved in road traffic accidents in Piedmont Region: psychoactive substances consumption

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    Introduction. The role played by psychoactive substances in road safety has become object of increasing interest: these substances can reduce driving performance and increase accidents risk. Aims of the study are to establish the dimension of the problem and to describe the characteristics of people involved in accidents under psychoactive substance effects. Methods. Target population consists of people from 18 to 60 years old involved in accidents afferent in Emergency Rooms. Subjects were interviewed by surveyors and a urines was collected for psychoactive substances screening. Results. In 18.5% of people we found substance consumption. Cocaine was the most frequently detected substance (9.5%), then benzodiazepines (7.5%), methadone, morphine and marijuana (THC) (3.5%). In 5.5% of subjects more then one substance was found. Considering only illegal substances detected, female have a higher risk to be consumers (OR = 1.36) and the young age (18-35 years) seems to be at higher prevalence and risk for substance use (OR = 1.86). Discussion. Considering all psychoactive substances detected, clearly the problem about substances consumption and driving is not restricted to youngest but involves all age groups. Conclusions. In order to decrease the number of accidents due to substance use, new prevention programmes able to involve also middle age groups should be planned

    About the connection between the CC_{\ell} power spectrum of the Cosmic Microwave Background and the Γm\Gamma_{m} Fourier spectrum of rings on the sky

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    In this article we present and study a scaling law of the mΓmm\Gamma_m CMB Fourier spectrum on rings which allows us (i) to combine spectra corresponding to different colatitude angles (e.g. several detectors at the focal plane of a telescope), and (ii) to recover the ClC_l power spectrum once the Γm\Gamma_m coefficients have been measured. This recovery is performed numerically below the 1% level for colatitudes Θ>80\Theta> 80^\circ degrees. In addition, taking advantage of the smoothness of the ClC_l and of the Γm\Gamma_m, we provide analytical expressions which allow to recover one of the spectrum at the 1% level, the other one being known.Comment: 8 pages, 8 figure

    Correctors for some nonlinear monotone operators

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    In this paper we study homogenization of quasi-linear partial differential equations of the form -\mbox{div}\left( a\left( x,x/\varepsilon _h,Du_h\right) \right) =f_h on Ω\Omega with Dirichlet boundary conditions. Here the sequence (εh)\left( \varepsilon _h\right) tends to 00 as hh\rightarrow \infty and the map a(x,y,ξ)a\left( x,y,\xi \right) is periodic in y,y, monotone in ξ\xi and satisfies suitable continuity conditions. We prove that uhuu_h\rightarrow u weakly in W01,p(Ω)W_0^{1,p}\left( \Omega \right) as h,h\rightarrow \infty , where uu is the solution of a homogenized problem of the form -\mbox{div}\left( b\left( x,Du\right) \right) =f on Ω.\Omega . We also derive an explicit expression for the homogenized operator bb and prove some corrector results, i.e. we find (Ph)\left( P_h\right) such that DuhPh(Du)0Du_h-P_h\left( Du\right) \rightarrow 0 in Lp(Ω,Rn)L^p\left( \Omega, \mathbf{R}^n\right)

    Some homogenization and corrector results for nonlinear monotone operators

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    This paper deals with the limit behaviour of the solutions of quasi-linear equations of the form \ \ds -\limfunc{div}\left(a\left(x, x/{\varepsilon _h},Du_h\right)\right)=f_h on Ω\Omega with Dirichlet boundary conditions. The sequence (εh)(\varepsilon _h) tends to 00 and the map a(x,y,ξ)a(x,y,\xi ) is periodic in yy, monotone in ξ\xi and satisfies suitable continuity conditions. It is proved that uhuu_h\rightarrow u weakly in H01,2(Ω)H_0^{1,2}(\Omega ), where uu is the solution of a homogenized problem \ -\limfunc{div}(b(x,Du))=f on Ω\Omega . We also prove some corrector results, i.e. we find (Ph)(P_h) such that DuhPh(Du)0Du_h-P_h(Du)\rightarrow 0 in L2(Ω,Rn)L^2(\Omega ,R^n)

    On weak convergence of locally periodic functions

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    We prove a generalization of the fact that periodic functions converge weakly to the mean value as the oscillation increases. Some convergence questions connected to locally periodic nonlinear boundary value problems are also considered.Comment: arxiv version is already officia

    QUBIC: The QU Bolometric Interferometer for Cosmology

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    One of the major challenges of modern cosmology is the detection of B-mode polarization anisotropies in the CMB. These originate from tensor fluctuations of the metric produced during the inflationary phase. Their detection would therefore constitute a major step towards understanding the primordial Universe. The expected level of these anisotropies is however so small that it requires a new generation of instruments with high sensitivity and extremely good control of systematic effects. We propose the QUBIC instrument based on the novel concept of bolometric interferometry, bringing together the sensitivity advantages of bolometric detectors with the systematics effects advantages of interferometry. Methods: The instrument will directly observe the sky through an array of entry horns whose signals will be combined together using an optical combiner. The whole set-up is located inside a cryostat. Polarization modulation will be achieved using a rotating half-wave plate and interference fringes will be imaged on two focal planes (separated by a polarizing grid) tiled with bolometers. We show that QUBIC can be considered as a synthetic imager, exactly similar to a usual imager but with a synthesized beam formed by the array of entry horns. Scanning the sky provides an additional modulation of the signal and improve the sky coverage shape. The usual techniques of map-making and power spectrum estimation can then be applied. We show that the sensitivity of such an instrument is comparable with that of an imager with the same number of horns. We anticipate a low level of beam-related systematics thanks to the fact that the synthesized beam is determined by the location of the primary horns. Other systematics should be under good control thanks to an autocalibration technique, specific to our concept, that will permit the accurate determination of most of the systematics parameters.Comment: 12 pages, 10 figures, submitted to Astronomy and Astrophysic
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