1,232 research outputs found
Fast Spherical Harmonic Analysis: a quick algorithm for generating and/or inverting full sky, high resolution CMB Anisotropy maps
We present a fast algorithm for generating full sky, high resolution () simulations of the CMB anisotropy pattern. We also discuss the inverse
problem, that of evaluating from such a map the full set of 's and
the spectral coefficients . We show that using an Equidistant
Cylindrical Projection of the sky substantially speeds up the calculations.
Thus, generating and/or inverting a full sky, high resolution map can be easily
achieved with present day computer technology.Comment: 13 pages, LaTex, 5 PostScript figures included, 1 colour plate
available (PostScript version, 1.6 Mb) at http://itovf2.roma2.infn.it/natoli
The AMS-02 Transition Radiation Detector for the International Space Station
The Alpha Magnetic Spectrometer (AMS-02) is a large experiment in the International Space Station (ISS) intended to measure primary cosmic ray spectra in space. It sits outside of the station, looking out into space. High-energy particles pass through it, interacting with different detectors on the way. The Transition Radiation Detector (TRD) contributes to distinguish an e or p signal reducing the p or e background by a rejection factor 10 to 10 in the energy range from 10 to 300 GeV. This detector will be used in conjunction with an electromagnetic calorimeter to provide an overall p rejection of 10 with 90% efficiency for positrons. AMS-02 TRD consists of 20 layers of straw proportional tubes alternating with layer of fiber fleece radiator. The layers are mounted in a stable and light carbon fiber composite/aluminum honeycomb octagonal support, fixed by an M-structure to the AMS-02 magnet flange. A space qualified redundant electronic subsystem processes signals coming from the 5248 straw tubes providing front-end readout, first level DAQ and interface to the AMS-02 trigger/DAQ system. The straw tubes are filled with a Xe:CO2 gas mixture provided by a gas circulating system capable to operate more than 3 years in space. The gas control system of the TRD is also an essential item for its performance. To obtain the required discriminating power, a stringent control of gas parameters is necessary. The construction of the detector is presente
Dose-Effects Models for Space Radiobiology: An Overview on Dose-Effect Relationships
Space radiobiology is an interdisciplinary science that examines the biological effects of ionizing radiation on humans involved in aerospace missions. The dose-effect models are one of the relevant topics of space radiobiology. Their knowledge is crucial for optimizing radioprotection strategies (e.g., spaceship and lunar space station-shielding and lunar/Mars village design), the risk assessment of the health hazard related to human space exploration, and reducing damages induced to astronauts from galactic cosmic radiation. Dose-effect relationships describe the observed damages to normal tissues or cancer induction during and after space flights. They are developed for the various dose ranges and radiation qualities characterizing the actual and the forecast space missions [International Space Station (ISS) and solar system exploration]. Based on a Pubmed search including 53 papers reporting the collected dose-effect relationships after space missions or in ground simulations, 7 significant dose-effect relationships (e.g., eye flashes, cataract, central nervous systems, cardiovascular disease, cancer, chromosomal aberrations, and biomarkers) have been identified. For each considered effect, the absorbed dose thresholds and the uncertainties/limitations of the developed relationships are summarized and discussed. The current knowledge on this topic can benefit from further in vitro and in vivo radiobiological studies, an accurate characterization of the quality of space radiation, and the numerous experimental dose-effects data derived from the experience in the clinical use of ionizing radiation for diagnostic or treatments with doses similar to those foreseen for the future space missions. The growing number of pooled studies could improve the prediction ability of dose-effect relationships for space exposure and reduce their uncertainty level. Novel research in the field is of paramount importance to reduce damages to astronauts from cosmic radiation before Beyond Low Earth Orbit exploration in the next future. The study aims at providing an overview of the published dose-effect relationships and illustrates novel perspectives to inspire future research
Letter to the Editor Regarding Management of Adult Patients with COVID-19 Outside Intensive Care Units: Guidelines from the Italian Society of Anti-Infective Therapy (SITA) and the Italian Society of Pulmonology (SIP)
Matched filters for coalescing binaries detection on massively parallel computers
We discuss some computational problems associated to matched filtering of
experimental signals from gravitational wave interferometric detectors in a
parallel-processing environment. We then specialize our discussion to the use
of the APEmille and apeNEXT processors for this task. Finally, we accurately
estimate the performance of an APEmille system on a computational load
appropriate for the LIGO and VIRGO experiments, and extrapolate our results to
apeNEXT.Comment: 19 pages, 6 figure
APE Results of Hadron Masses in Full QCD Simulations
We present numerical results obtained in full QCD with 2 flavors of Wilson
fermions. We discuss the relation between the phase of Polyakov loops and the
{\bf sea} quarks boundary conditions. We report preliminary results about the
HMC autocorrelation of the hadronic masses, on a lattice
volume, at with .Comment: 3 pages, compressed ps-file (uufiles), Contribution to Lattice 9
Scaling, asymptotic scaling and Symanzik improvement. Deconfinement temperature in SU(2) pure gauge theory
We report on a high statistics simulation of SU(2) pure gauge field theory at
finite temperature, using Symanzik action. We determine the critical coupling
for the deconfinement phase transition on lattices up to 8 x 24, using Finite
Size Scaling techniques. We find that the pattern of asymptotic scaling
violation is essentially the same as the one observed with conventional, not
improved action. On the other hand, the use of effective couplings defined in
terms of plaquette expectation values shows a precocious scaling, with respect
to an analogous analysis of data obtained by the use of Wilson action, which we
interpret as an effect of improvement.Comment: 43 pages ( REVTeX 3.0, self-extracting shell archive, 13 PostScript
figs.), report IFUP-TH 21/93 (2 TYPOS IN FORMULAS CORRECTED,1 CITATION
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