53 research outputs found
A survey on hospitalised community-acquired pneumonia in Italy.
Background and aim. Community Acquired Pneumonia (CAP) remains a major cause of disease and death. We evaluated the levels of care, the outcome and the characteristics of hospitalised patients with CAP in a primary hospital in Italy. We also investigated the value of both the Pneumonia Severity Index (PSI) and the modified Appropriateness Evaluation Protocol (AEP) for recognising both the outcome and the unnecessary admissions and stay of hospitalised patients with CAP. Methods. A retrospective review of all the charts of adult patients with CAP at Manerbio, Brescia, Italy between January 2001 and December 2002 was performed. Results. We evaluated 148 patients; their mean age (±SD) was 70 (±17) years; 34% were female. Most patients (87%) had at least a concomitant co-morbid disease. The overall survival rate at 30 days was 88%. All but one death occurred in the high-risk group of patients according to the PSI. On the contrary, the death rate of patients with inappropriate hospital admission according to the AEP was high. Patients with high PSI score had a significantly longer hospital length of stay than the low-risk group. However, a substantial part of the hospital stay did not show any justification into the charts. Conclusions. The PSI, but not the AEP, upon hospital admission, was useful for evaluating the outcome of patients with CAP. The PSI score and the modified AEP can be useful for assessing the appropriateness of hospitalisation for patients with CAP. There is the need for a practical and validated tool to support physicians in their decision making regarding the early and safe discharge of hospitalised patients with CAP
The FEL SASE operation, bunch compression and the beam heater
We discuss the conditions required for an optimal SASE FEL operation when
bunch compression techniques are exploited to enhance the bunch peak current.
We discuss the case of velocity bunching and magnetic bunch compression. With
the reference to the latter technique we provide a quantitative estimate of the
amount of laser heater power necessary to suppress the micro-bunching
instability without creating any problem to the SASE dynamic
Conceptual Design of a Soft Xâray SASEâFEL Source
FELs based on SASE are believed to be powerful tools to explore the frontiers of basic sciences, from physics to chemistry to biology. Intense R&D programs have started in the USA and Europe in order to understand the SASE physics and to prove the feasibility of these sources. The allocation of considerable resources in the Italian National Research Plan (PNR) brought about the formation of a CNRâENEAâINFNâUniversity of Roma "Tor Vergata" study group. A conceptual design study has been developed and possible schemes for linac sources have been investigated, bringing to the SPARX proposal. We report in this paper the results of a preliminary start to end simulation concerning one option we are considering based on an Sâband normal conducting linac with high brightness photoinjector integrated in a RF compressor
Beam spin asymmetry measurements of deeply virtual Ï0 production with CLAS12
The new experimental measurements of beam spin asymmetry were performed for the deeply virtual exclusive pi0 production in a wide kinematic region with the photon virtualities Q2 up to 6.6 GeV2 and the Bjorken scaling variable xB in the valence regime. The data were collected by the CEBAF Large Acceptance Spectrometer (CLAS12) at Jefferson Lab with longitudinally polarized 10.6 GeV electrons scattered on an unpolarized liquid-hydrogen target. Sizable asymmetry values indicate a substantial contribution from transverse virtual photon amplitudes to the polarized structure functions. The interpretation of these measurements in terms of the Generalized Parton Distributions (GPDs) demonstrates their sensitivity to the chiral-odd GPD ET, which contains information on quark transverse spin densities in unpolarized and polarized nucleons and provides access to the nucleon's transverse anomalous magnetic moment. Additionally, the data were compared to a theoretical model based on a Regge formalism that was extended to the high photon virtualities
Status of the SPARX FEL project
The SPARX project consists in an X-ray-FEL facility jointly supported by MIUR (Research Department of Italian Government), Regione Lazio, CNR, ENEA, INFN and Rome University Tor Vergata. It is the natural extension of the ongoing activities of the SPARC collaboration. The aim is the generation of electron beams characterized by ultra-high peak brightness at the energy of 1 and 2 GeV, for the first and the second phase respectively. The beam is expected to drive a single pass FEL experiment in the range of 13.5-6 nm and 6-1.5 nm, at 1 GeV and 2 GeV respectively, both in SASE and SEEDED FEL configurations. A hybrid scheme of RF and magnetic compression will be adopted, based on the expertise achieved at the SPARC high brightness photoinjector presently under commissioning at Frascati INFNLNF Laboratories. The use of superconducting and exotic undulator sections will be also exploited. In this paper we report the progress of the collaboration together with start to end simulation results based on a combined scheme of RF compression techniques
Beam Charge Asymmetries for Deeply Virtual Compton Scattering on the Proton at CLAS12
International audienceThe parameterization of the nucleon structure through Generalized Parton Distributions (GPDs) shed a new light on the nucleon internal dynamics. For its direct interpretation, Deeply Virtual Compton Scattering (DVCS) is the golden channel for GPDs investigation. The DVCS process interferes with the Bethe-Heitler (BH) mechanism to constitute the leading order amplitude of the process. The study of the reaction with polarized positron and electron beams gives a complete set of unique observables to unravel the different contributions to the cross section. This separates the different reaction amplitudes, providing a direct access to their real and imaginary parts which procures crucial constraints on the model dependences and associated systematic uncertainties on GPDs extraction. The real part of the BH-DVCS interference amplitude is particularly sensitive to the -term which parameterizes the Gravitational Form Factors of the nucleon. The separation of the imaginary parts of the interference and DVCS amplitudes provides insights on possible higher-twist effects. We propose to measure the unpolarized and polarized Beam Charge Asymmetries (BCAs) of the process on an unpolarized hydrogen target with {\tt CLAS12}, using polarized positron and electron beams at 10.6~GeV. The azimuthal and -dependences of the unpolarized and polarized BCAs will be measured over a large phase space using a 100 day run with a luminosity of 0.66cms
Beam Charge Asymmetries for Deeply Virtual Compton Scattering on the Proton at CLAS12
International audienceThe parameterization of the nucleon structure through Generalized Parton Distributions (GPDs) shed a new light on the nucleon internal dynamics. For its direct interpretation, Deeply Virtual Compton Scattering (DVCS) is the golden channel for GPDs investigation. The DVCS process interferes with the Bethe-Heitler (BH) mechanism to constitute the leading order amplitude of the process. The study of the reaction with polarized positron and electron beams gives a complete set of unique observables to unravel the different contributions to the cross section. This separates the different reaction amplitudes, providing a direct access to their real and imaginary parts which procures crucial constraints on the model dependences and associated systematic uncertainties on GPDs extraction. The real part of the BH-DVCS interference amplitude is particularly sensitive to the -term which parameterizes the Gravitational Form Factors of the nucleon. The separation of the imaginary parts of the interference and DVCS amplitudes provides insights on possible higher-twist effects. We propose to measure the unpolarized and polarized Beam Charge Asymmetries (BCAs) of the process on an unpolarized hydrogen target with {\tt CLAS12}, using polarized positron and electron beams at 10.6~GeV. The azimuthal and -dependences of the unpolarized and polarized BCAs will be measured over a large phase space using a 100 day run with a luminosity of 0.66cms
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