672 research outputs found
Probing neutrino masses with CMB lensing extraction
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
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
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
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 power spectrum of the Cosmic Microwave Background and the Fourier spectrum of rings on the sky
In this article we present and study a scaling law of the 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 power spectrum once the
coefficients have been measured. This recovery is performed numerically below
the 1% level for colatitudes degrees. In addition, taking
advantage of the smoothness of the and of the , 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
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 with Dirichlet boundary conditions. Here the
sequence tends to as
and the map is periodic in monotone in
and satisfies suitable continuity conditions. We prove that
weakly in as where
is the solution of a homogenized problem of the form -\mbox{div}\left(
b\left( x,Du\right) \right) =f on We also derive an explicit
expression for the homogenized operator and prove some corrector results,
i.e. we find such that in
Some homogenization and corrector results for nonlinear monotone operators
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 with Dirichlet boundary conditions.
The sequence tends to and the map is
periodic in , monotone in and satisfies suitable continuity
conditions. It is proved that weakly in , where is the solution of a homogenized problem \
-\limfunc{div}(b(x,Du))=f on . We also prove some corrector results,
i.e. we find such that in
On weak convergence of locally periodic functions
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
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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