On vanishing theorems for Higgs bundles

We introduce the notion of Hermitian Higgs bundle as a natural generalization of the notion of Hermitian vector bundle and we study some vanishing theorems concerning Hermitian Higgs bundles when the base manifold is a compact complex manifold. We show that a first vanishing result, proved for these objects when the base manifold was K\"ahler, also holds when the manifold is compact complex. From this fact and some basic properties of Hermitian Higgs bundles, we conclude several results. In particular we show that, in analogy to the classical case, there are vanishing theorems for invariant sections of tensor products of Higgs bundles. Then, we prove that a Higgs bundle admits no nonzero invariant sections if there is a condition of negativity on the greatest eigenvalue of the Hitchin-Simpson mean curvature. Finally, we prove that invariant sections of certain tensor products of a weak Hermitian-Yang-Mills Higgs bundle are all parallel in the classical sense.Comment: 10 Pages, some typos corrected and minor change

Preliminary Results for LP VPE X-Ray Detectors

Thick epitaxial layers have been grown using Low Pressure Vapour Phase Epitaxy techniques with low free carrier concentrations . This type of material is attractive as a medium for X-ray detection, because of its high conversion efficiency for X-rays in the medically interesting energy range.Comment: 4 pages. PS file only - original in WORD. Also available at http://ppewww.ph.gla.ac.uk/preprints/97/07

Test beam Characterizations of 3D Silicon Pixel detectors

3D silicon detectors are characterized by cylindrical electrodes perpendicular to the surface and penetrating into the bulk material in contrast to standard Si detectors with planar electrodes on its top and bottom. This geometry renders them particularly interesting to be used in environments where standard silicon detectors have limitations, such as for example the radiation environment expected in an LHC upgrade. For the first time, several 3D sensors were assembled as hybrid pixel detectors using the ATLAS-pixel front-end chip and readout electronics. Devices with different electrode configurations have been characterized in a 100 GeV pion beam at the CERN SPS. Here we report results on unirradiated devices with three 3D electrodes per 50 x 400 um2 pixel area. Full charge collection is obtained already with comparatively low bias voltages around 10 V. Spatial resolution with binary readout is obtained as expected from the cell dimensions. Efficiencies of 95.9% +- 0.1 % for tracks parallel to the electrodes and of 99.9% +- 0.1 % at 15 degrees are measured. The homogeneity of the efficiency over the pixel area and charge sharing are characterized.Comment: 5 pages, 7 figure

Recent results on GaAs detectors - 137

The present understanding of the charge collection in GaAs detectors with respect to the materials used and its processing are discussed. The radiation induced degradation of the charge collection efficiency and the leakage current of the detectors are summarised. The status of strip and pixel detectors for the ATLAS experiment are reported along with the latest results from GaAs X-ray detectors for non-high energy physics applications.Comment: 7 pages. 4 postscript figures + 1 postscript preprint logo + 1 LaTeX file + 1 style file. Also available at http://ppewww.ph.gla.ac.uk/preprints/97/05

Prevenció d'RNM causats per PRM de seguretat: ajust posològic de medicaments en ancians polimedicats amb funció renal disminiuïda atesos a les farmàcies comunitàries

El creixement constant de la població de gent gran ha portat un increment de l'ús dels medicaments i ha originat la denominada polimedicació, principalment a causa del nombre de malalties cròniques associades a aquesta franja d'edat i del deteriorament fisiològic i natural de l'organisme. (1) El càlcul és que l'any 2015, a Catalunya, el percentatge de persones de més de 65 anys superarà el 18,5% i les persones de més de 80 anys seran aproximadament un 5,6% de la població. (2) La mitjana del nombre de medicaments utilitzats per les persones grans oscil·la entre 2 i 5 i pot augmentar si tenim en compte els medicaments que no necessiten prescripció mèdica. (3) Es calcula que un 65% de la gent gran té prescrits tres o més medicaments i un 30% més de cinc. (4) Si bé els medicaments estan formulats amb criteris de protecció i seguretat, els riscos associats a la utilització sempre són presents. La utilització correcta requereix un balanç favorable i individual de la relació benefici i risc que aquests medicaments poden produir. La seguretat n'és una part primordial i defineix en sentit positiu l'absència de toxicitat o de riscos. (5) Actualment, la seguretat del pacient es considera un tret essencial de la qualitat assistencial i la manca d'aquest tret podria comprometre negativament dimensions com l'efectivitat terapèutica..

Light Ions Response of Silicon Carbide Detectors

Silicon carbide (SiC) Schottky diodes 21 mum thick with small surfaces and high N-dopant concentration have been used to detect alpha particles and low energy light ions. In particular 12C and 16O beams at incident energies between 5 and 18 MeV were used. The diode active-region depletion-thickness, the linearity of the response, energy resolution and signal rise-time were measured for different values of the applied reverse bias. Moreover the radiation damage on SiC diodes irradiated with 53 MeV 16O beam has been explored. The data show that SiC material is radiation harder than silicon but at least one order of magnitude less hard than epitaxial silicon diodes. An inversion in the signal was found at a fluence of 10^15 ions/cm^2.Comment: 20 pages, 16 figures, submitted for publication to Nuclear Instruments and Methods in Physics Research