An electromagnetic shashlik calorimeter with longitudinal segmentation

A novel technique for longitudinal segmentation of shashlik calorimeters has been tested in the CERN West Area beam facility. A 25 tower very fine samplings e.m. calorimeter has been built with vacuum photodiodes inserted in the first 8 radiation lengths to sample the initial development of the shower. Results concerning energy resolution, impact point reconstruction and electron/pion separation are reported.Comment: 13 pages, 12 figure

Debris disks in main sequence binary systems

We observed 69 A3-F8 main sequence binary star systems using the Multiband Imaging Photometer for Spitzer onboard the Spitzer Space Telescope. We find emission significantly in excess of predicted photospheric flux levels for 9(+4/-3)% and 40(+7/-6)% of these systems at 24 and 70 microns, respectively. Twenty two systems total have excess emission, including four systems that show excess emission at both wavelengths. A very large fraction (nearly 60%) of observed binary systems with small (<3 AU) separations have excess thermal mission. We interpret the observed infrared excesses as thermal emission from dust produced by collisions in planetesimal belts. The incidence of debris disks around main sequence A3-F8 binaries is marginally higher than that for single old AFGK stars. Whatever combination of nature (birth conditions of binary systems) and nurture (interactions between the two stars) drives the evolution of debris disks in binary systems, it is clear that planetesimal formation is not inhibited to any great degree. We model these dust disks through fitting the spectral energy distributions and derive typical dust temperatures in the range 100--200 K and typical fractional luminosities around 10^-5, with both parameters similar to other Spitzer-discovered debris disks. Our calculated dust temperatures suggest that about half the excesses we observe are derived from circumbinary planetesimal belts and around one third of the excesses clearly suggest circumstellar material. Three systems with excesses have dust in dynamically unstable regions, and we discuss possible scenarios for the origin of this short-lived dust.Comment: ApJ, in press. 57 pages, including 7 figures (one of which is in color

La grande crociata. Il 18 aprile nel Veneto

Il fascicolo analizza il tornante decisivo delle lezioni politiche dell'aprile 1948 analizzando la mobilitazione del clero e dell'associazionismo cattolico in alcune province venete

Early red nucleus atrophy in relapse-onset multiple sclerosis

No study has investigated red nucleus (RN) atrophy in multiple sclerosis (MS) despite cerebellum and its connections are elective sites of MS-related pathology. In this study, we explore RN atrophy in early MS phases and its association with cerebellar damage (focal lesions and atrophy) and physical disability. Thirty-seven relapse-onset MS (RMS) patients having mean age of 35.6 ± 8.5 (18–56) years and mean disease duration of 1.1 ± 1.5 (0–5) years, and 36 age- and sex-matched healthy controls (HC) were studied. Cerebellar and RN lesions and volumes were analyzed on 3 T-MRI images. RMS did not differ from HC in cerebellar lobe volumes but significantly differed in both right (107.84 ± 13.95 mm3 vs. 99.37 ± 11.53 mm3, p =.019) and left (109.71 ± 14.94 mm3 vs. 100.47 ± 15.78 mm3, p =.020) RN volumes. Cerebellar white matter lesion volume (WMLV) inversely correlated with both right and left RN volumes (r = −.333, p =.004 and r = −.298, p =.010, respectively), while no correlation was detected between RN volumes and mean cortical thickness, cerebellar gray matter lesion volume, and supratentorial WMLV (right RN: r = −.147, p =.216; left RN: r = −.153, p =.196). Right, but not left, RN volume inversely correlated with midbrain WMLV (r = −.310, p =.008), while no correlation was observed between whole brainstem WMLV and either RN volumes (right RN: r = −.164, p =.164; left RN: r = −.64, p =.588). Finally, left RN volume correlated with vermis VIIb (r =.297, p =.011) and right interposed nucleus (r =.249, p =.034) volumes. We observed RN atrophy in early RMS, likely resulting from anterograde axonal degeneration starting in cerebellar and midbrain WML. RN atrophy seems a promising marker of neurodegeneration and/or cerebellar damage in RMS

An electromagnetic shashlik calorimeter with longitudinal segmentation

A novel technique for longitudinal segmentation of shashlik calorimeters has been tested in the CERN West Area beam facility. A 25 tower e.m. calorimeter has been built with vacuum photodiodes inserted in the first 8 radiation lengths to sample the initial development of the shower. Results concerning energy resolution, impact point reconstruction and $e/\pi$ separation are reported.A novel technique for longitudinal segmentation of shashlik calorimeters has been tested in the CERN West Area beam facility. A 25 tower very fine samplings e.m. calorimeter has been built with vacuum photodiodes inserted in the first 8 radiation lengths to sample the initial development of the shower. Results concerning energy resolution, impact point reconstruction and electron/pion separation are reported

A shashlik calorimeter with longitudinal segmentation for a linear collider

Two techniques for longitudinal segmentation of shashlik calorimeters are proposed. Beam tests have demonstrated the technical feasibility of longitudinally segmented shashlik calorimeters in which longitudinal sampling is performed by lateral vacuum photodiodes or by using two scintillator types with different decay times. Results concerning energy resolution and e/π separation are presente