386 research outputs found

    PMH40 How do Patients Describe Their Depression? - Incorporating the Patient's Voice Into Instrument Development

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    Letter from CGIAR Chairman Ismail Serageldin to CGIAR heads of delegation, board chairs, center directors and the TAC chairman and secretariat, leading up to ICW94. Serageldin described the work of various ad hoc and standing bodies in preparation for International Centers Week 1994 and the Ministerial-level Meeting being planned for early 1995. He also announced that as a result of additional funding by donors and matching funds from the World Bank, the 1994 core program was fully funded

    Infinite temperature limit of meson spectral functions calculated on the lattice

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    We analyze the cut-off dependence of mesonic spectral functions calculated at finite temperature on Euclidean lattices with finite temporal extent. In the infinite temperature limit we present analytic results for lattice spectral functions calculated with standard Wilson fermions as well as a truncated perfect action. We explicitly determine the influence of `Wilson doublers' on the high momentum structure of the mesonic spectral functions and show that this cut-off effect is strongly suppressed when using an improved fermion action.Comment: 25 pages, 8 figure

    Semi-leptonic decays of heavy flavours on a fine grained lattice

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    We present the results of a numerical calculation of semi-leptonic form factors relevant for heavy flavour meson decays into light mesons, at β=6.4 on a 243×60 lattice, using the Wilson action in the quenched approximation. We obtain f+K(0)=0.65±0.18, V(0)=0.95±0.34, A1(0)=0.63±0.14 and A2(0)=0.45±0.33. We also obtain A1(q2max)=0.62±0.09, V(0)/A1(0)=1.5±0.28 and A2(0)/A1(0)=0.7±0.4. The results for f+K(0), V(0) and A1(0) are consistent with the experimental data and with previous lattice determinations with larger lattice spacings. In the case of A2(0) the errors are too large to draw any firm conclusion. We have also extrapolated the form factors to the B meson, showing a behaviour compatible with the predictions by the heavy quark effective theory (HQET). Within large uncertainties, our results suggest that A2/A1 increases with the heavy quark mass. We also get very rough estimates for the partial decay widths B→πlνl)=|Vub|2(12±8)1012s−1 and Γ(B→ρlνl)=|Vub|2(13±12)1012s−1, which can be used to give upper bounds on the rates

    Geriatric screeners 2.0: time for a paradigm shift in emergency department vulnerability research

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    Pathophysiology, epidemiology and therapy of agein

    Accretion, Outflows, and Winds of Magnetized Stars

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    Many types of stars have strong magnetic fields that can dynamically influence the flow of circumstellar matter. In stars with accretion disks, the stellar magnetic field can truncate the inner disk and determine the paths that matter can take to flow onto the star. These paths are different in stars with different magnetospheres and periods of rotation. External field lines of the magnetosphere may inflate and produce favorable conditions for outflows from the disk-magnetosphere boundary. Outflows can be particularly strong in the propeller regime, wherein a star rotates more rapidly than the inner disk. Outflows may also form at the disk-magnetosphere boundary of slowly rotating stars, if the magnetosphere is compressed by the accreting matter. In isolated, strongly magnetized stars, the magnetic field can influence formation and/or propagation of stellar wind outflows. Winds from low-mass, solar-type stars may be either thermally or magnetically driven, while winds from massive, luminous O and B type stars are radiatively driven. In all of these cases, the magnetic field influences matter flow from the stars and determines many observational properties. In this chapter we review recent studies of accretion, outflows, and winds of magnetized stars with a focus on three main topics: (1) accretion onto magnetized stars; (2) outflows from the disk-magnetosphere boundary; and (3) winds from isolated massive magnetized stars. We show results obtained from global magnetohydrodynamic simulations and, in a number of cases compare global simulations with observations.Comment: 60 pages, 44 figure

    Exploring the stability of super heavy elements: First measurement of the fission barrier of 254No

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    The gamma-ray multiplicity and total energy emitted by the heavy nucleus 254No have been measured at 2 different beam energies. From these measurements, the initial distributions of spin I and excitation energy E * of 254No were constructed. The distributions display a saturation in excitation energy, which allows a direct determination of the fission barrier. 254No is the heaviest shell-stabilized nucleus with a measured fission barrier. © Owned by the authors, published by EDP Sciences, 2014

    How well do we understand the reaction rate of C burning?

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    Carbon burning plays a crucial role in stellar evolution, where this reaction is an important route for the production of heavier elements. A particle-γ coincidence technique that minimizes the backgrounds to which this reaction is subject and provides reliable cross sections has been used at the Argonne National Laboratory to measure fusion cross-sections at deep sub-barrier energies in the 12C+12C system. The corresponding excitation function has been extracted down to a cross section of about 6 nb. This indicates the existence of a broad S-factor maximum for this system. Experimental results are presented and discussed

    Reaction rate for carbon burning in massive stars

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    Carbon burning is a critical phase for nucleosynthesis in massive stars. The conditions for igniting this burning stage, and the subsequent isotope composition of the resulting ashes, depend strongly on the reaction rate for C12+C12 fusion at very low energies. Results for the cross sections for this reaction are influenced by various backgrounds encountered in measurements at such energies. In this paper, we report on a new measurement of C12+C12 fusion cross sections where these backgrounds have been minimized. It is found that the astrophysical S factor exhibits a maximum around Ecm=3.5-4.0 MeV, which leads to a reduction of the previously predicted astrophysical reaction rate
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