197 research outputs found

    Aparcamiento en Breuninger

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    El problema del estacionamiento de vehículos en las grandes ciudades, precisamente en sus centros vitales, de comercio y de relación, se agudiza con el incremento incesante de automóviles. Los Municipios demuestran su preocupación creando lugares y espacios capaces para albergarlos. Esto mismo hacen, con un deseo muy encomiable, las grandes casas comerciales, de la que es buena muestra la Breuninger, de Stuttgart, uno de los más poderosos comercios de tejidos de la capital

    Silicon detector for a Compton Camera in Nuclear Medical Imaging

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    Electronically collimated gamma ca\-me\-ras based on Com\-pton scattering in silicon pad sensors may improve imaging in nuclear medicine and bio-medical research. The work described here concentrates on the silicon pad detector developed for a prototype Compton camera. The silicon pad sensors are read out using low noise VLSI CMOS chips and novel fast triggering chips. Depending on the application a light weight and dense packaging of sensors and its readout electronics on a hybrid is required. We describe the silicon pad sensor and their readout with the newly designed hybrid. %The silicon detector of a Compton camera %may contain up to 10510^5~analogue channels requiring %a fast and low cost data acquisition system. We also describe a modular and low-cost data acquisition system (CCDAQ) based on a digital signal processor which is interfaced to the EPP port of personal computers. Using the CCDAQ and the hybrids energy spectra of gamma-ray photons from technetium (4399m^{\rm 99m}_{43}Tc) and americium (95241^{241}_{95}Am) were acquired with an energy resolution of 2.45~keV FWHM for the 140.5~keV photo-absorption line of 4399m^{\rm 99m}_{43}Tc. For all pads the discrimination threshold in the trigger chip was between (15 and 25)~keV

    Measurement of inclusive D*+- and associated dijet cross sections in photoproduction at HERA

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    Inclusive photoproduction of D*+- mesons has been measured for photon-proton centre-of-mass energies in the range 130 < W < 280 GeV and a photon virtuality Q^2 < 1 GeV^2. The data sample used corresponds to an integrated luminosity of 37 pb^-1. Total and differential cross sections as functions of the D* transverse momentum and pseudorapidity are presented in restricted kinematical regions and the data are compared with next-to-leading order (NLO) perturbative QCD calculations using the "massive charm" and "massless charm" schemes. The measured cross sections are generally above the NLO calculations, in particular in the forward (proton) direction. The large data sample also allows the study of dijet production associated with charm. A significant resolved as well as a direct photon component contribute to the cross section. Leading order QCD Monte Carlo calculations indicate that the resolved contribution arises from a significant charm component in the photon. A massive charm NLO parton level calculation yields lower cross sections compared to the measured results in a kinematic region where the resolved photon contribution is significant.Comment: 32 pages including 6 figure

    R & D for collider beauty physics at the LHC

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    We propose an R&D program for the development of a Beauty trigger and innovative elements of the associated spectrometer. A series of short test runs is proposed at the SPS p-pbar Collider with the minimal spectrometer which will allow a credible B signal to be obtained in an invariant mass spectrum of reconstructed B mesons. The program builds on the success of the recent collider run of the P238 Collaboration, in which clean signals from beam-beam interactions were observed in a large silicon strip microvertex detector running 1.5 mm from the circulating beams. A continuing successful R&D program of the type proposed could ultimately lead to a collider experiment at the LHC to study CP Violation and rare B decays

    Quadrupole collectivity in Ca 42 from low-energy Coulomb excitation with AGATA

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    A Coulomb-excitation experiment to study electromagnetic properties of Ca42 was performed using a 170-MeV calcium beam from the TANDEM XPU facility at INFN Laboratori Nazionali di Legnaro. γ rays from excited states in Ca42 were measured with the AGATA spectrometer. The magnitudes and relative signs of ten E2 matrix elements coupling six low-lying states in Ca42, including the diagonal E2 matrix elements of 21+ and 22+ states, were determined using the least-squares code gosia. The obtained set of reduced E2 matrix elements was analyzed using the quadrupole sum rule method and yielded overall quadrupole deformation for 01,2+ and 21,2+ states, as well as triaxiality for 01,2+ states, establishing the coexistence of a weakly deformed ground-state band and highly deformed slightly triaxial sideband in Ca42. The experimental results were compared with the state-of-the-art large-scale shell-model and beyond-mean-field calculations, which reproduce well the general picture of shape coexistence in Ca42

    Superdeformed and Triaxial States in Ca 42

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    Shape parameters of a weakly deformed ground-state band and highly deformed slightly triaxial sideband in ^{42}Ca were determined from E2 matrix elements measured in the first low-energy Coulomb excitation experiment performed with AGATA. The picture of two coexisting structures is well reproduced by new state-of-the-art large-scale shell model and beyond-mean-field calculations. Experimental evidence for superdeformation of the band built on 0_{2}^{+} has been obtained and the role of triaxiality in the A∼40 mass region is discussed. Furthermore, the potential of Coulomb excitation as a tool to study superdeformation has been demonstrated for the first time

    Measurement of the Diffractive Cross Section in Deep Inelastic Scattering using ZEUS 1994 Data

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    The DIS diffractive cross section, dσγpXNdiff/dMXd\sigma^{diff}_{\gamma^* p \to XN}/dM_X, has been measured in the mass range MX<15M_X < 15 GeV for γp\gamma^*p c.m. energies 60<W<20060 < W < 200 GeV and photon virtualities Q2=7Q^2 = 7 to 140 GeV2^2. For fixed Q2Q^2 and MXM_X, the diffractive cross section rises rapidly with WW, dσγpXNdiff(MX,W,Q2)/dMXWadiffd\sigma^{diff}_{\gamma^*p \to XN}(M_X,W,Q^2)/dM_X \propto W^{a^{diff}} with adiff=0.507±0.034(stat)0.046+0.155(syst)a^{diff} = 0.507 \pm 0.034 (stat)^{+0.155}_{-0.046}(syst) corresponding to a tt-averaged pomeron trajectory of \bar{\alphapom} = 1.127 \pm 0.009 (stat)^{+0.039}_{-0.012} (syst) which is larger than \bar{\alphapom} observed in hadron-hadron scattering. The WW dependence of the diffractive cross section is found to be the same as that of the total cross section for scattering of virtual photons on protons. The data are consistent with the assumption that the diffractive structure function F2D(3)F^{D(3)}_2 factorizes according to \xpom F^{D(3)}_2 (\xpom,\beta,Q^2) = (x_0/ \xpom)^n F^{D(2)}_2(\beta,Q^2). They are also consistent with QCD based models which incorporate factorization breaking. The rise of \xpom F^{D(3)}_2 with decreasing \xpom and the weak dependence of F2D(2)F^{D(2)}_2 on Q2Q^2 suggest a substantial contribution from partonic interactions

    Season of Birth and Dopamine Receptor Gene Associations with Impulsivity, Sensation Seeking and Reproductive Behaviors

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    Season of birth (SOB) has been associated with many physiological and psychological traits including novelty seeking and sensation seeking. Similar traits have been associated with genetic polymorphisms in the dopamine system. SOB and dopamine receptor genetic polymorphisms may independently and interactively influence similar behaviors through their common effects on the dopaminergic system.Based on a sample of 195 subjects, we examined whether SOB was associated with impulsivity, sensation seeking and reproductive behaviors. Additionally we examined potential interactions of dopamine receptor genes with SOB for the same set of traits. Phenotypes were evaluated using the Sociosexual Orientation Inventory, the Barratt Impulsivity Scale, the Eysenck Impulsivity Questionnaire, the Sensation Seeking Scale, and the Delay Discounting Task. Subjects were also asked about their age at first sex as well as their desired age at the birth of their first child. The dopamine gene polymorphisms examined were Dopamine Receptor D2 (DRD2) TaqI A and D4 (DRD4) 48 bp VNTR. Primary analyses included factorial genderxSOB ANOVAs or binary logistic regression models for each dependent trait. Secondary analysis extended the factorial models by also including DRD2 and DRD4 genotypes as independent variables. Winter-born males were more sensation seeking than non-winter born males. In factorial models including both genotype and season of birth as variables, two previously unobserved effects were discovered: (1) a SOBxDRD4 interaction effect on venturesomeness and (2) a DRD2xDRD4 interaction effect on sensation seeking.These results are consistent with past findings that SOB is related to sensation seeking. Additionally, these results provide tentative support for the hypothesis that SOB modifies the behavioral expression of dopaminergic genetic polymorphism. These findings suggest that SOB should be included in future studies of risky behaviors and behavioral genetic studies of the dopamine system
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