830 research outputs found

    A qualitative study of the contribution of pharmacists to heart failure management in Scotland

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    Study objectives: (1) To identify the medication management needs of chronic heart failure (CHF) patients and their caregivers; (2) To examine the perceived support for medication management available to these people from health professionals; (3) To identify the actual and potential perceived contribution of pharmacists to medication management. Setting: A mixed urban/ rural region in the west of Scotland. Design: Semi-structured qualitative research interviews. Participants: A total of 50 people with CHF (NYHA Class II and III) due to left ventricular systolic dysfunction (33 males; mean age 67 years, 17 females; mean age 68 years) and 30 nominated caregivers recruited from the outpatient departments of two hospitals in the West of Scotland. Sampling was purposive to include patients from a range of CHF severity, ages and sexes. Main results: Managing medications was a responsibility shared by both the patients with CHF and caregivers. Treatment regimens were reported to be difficult to comply with. Health professionals were seen to provide little support for medication management. Pharmacists were viewed as being a good and accessible source of practical assistance who were also knowledgeable about the individual’s heart health history. Participants reported valuing advice from pharmacists about the side effects of medications and for their assistance in reducing the complex logistics of medication management and in having medications delivered. Conclusions: Patients with CHF and caregivers voiced a willingness to try to manage their medication regimen accurately but had a limited capacity to do so. Pharmacists were viewed as providing valuable support to patients with CHF and their caregivers, in terms of medication management. The extended role of pharmacists in medication management of CHF should be encouraged

    Geometrical dissipation for dynamical systems

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    On a Riemannian manifold (M,g)(M,g) we consider the k+1k+1 functions F1,...,Fk,GF_1,...,F_k,G and construct the vector fields that conserve F1,...,FkF_1,...,F_k and dissipate GG with a prescribed rate. We study the geometry of these vector fields and prove that they are of gradient type on regular leaves corresponding to F1,...,FkF_1,...,F_k. By using these constructions we show that the cubic Morrison dissipation and the Landau-Lifschitz equation can be formulated in a unitary form

    Action-gradient-minimizing pseudo-orbits and almost-invariant tori

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    Transport in near-integrable, but partially chaotic, 11/21 1/2 degree-of-freedom Hamiltonian systems is blocked by invariant tori and is reduced at \emph{almost}-invariant tori, both associated with the invariant tori of a neighboring integrable system. "Almost invariant" tori with rational rotation number can be defined using continuous families of periodic \emph{pseudo-orbits} to foliate the surfaces, while irrational-rotation-number tori can be defined by nesting with sequences of such rational tori. Three definitions of "pseudo-orbit," \emph{action-gradient--minimizing} (AGMin), \emph{quadratic-flux-minimizing} (QFMin) and \emph{ghost} orbits, based on variants of Hamilton's Principle, use different strategies to extremize the action as closely as possible. Equivalent Lagrangian (configuration-space action) and Hamiltonian (phase-space action) formulations, and a new approach to visualizing action-minimizing and minimax orbits based on AGMin pseudo-orbits, are presented.Comment: Accepted for publication in a special issue of Communications in Nonlinear Science and Numerical Simulation (CNSNS) entitled "The mathematical structure of fluids and plasmas : a volume dedicated to the 60th birthday of Phil Morrison

    Baryon Spectra and AdS/CFT Correspondence

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    We provide a detailed map between wrapped D3-branes in Anti-de Sitter (AdS) backgrounds and dibaryon operators in the corresponding conformal field theory (CFT). The effective five dimensional action governing the dynamics of AdS space contains a U(1)RU(1)_R gauge field that mediates interactions between objects possessing R-charge. We show that the U(1)RU(1)_R charge of these wrapped D3-branes as measured by the gauge field matches the R-charge of the dibaryons expected from field theory considerations. We are able, through a careful probe brane calculation in an AdS5×T1,1AdS_5\times T^{1,1} background, to understand the exact relation between the mass of the wrapped D3-brane and the dimension of the corresponding dibaryon. We also make some steps toward matching the counting of dibaryon operators in the CFT with the ground states of a supersymmetric quantum mechanical system whose target space is the moduli space of D-branes. Finally, we discuss BPS excitations of the D3-brane and compare them with higher dimension operators in the CFT.Comment: 24 pages, typos correcte

    Closed string tachyons, flips and conifolds

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    Following the analysis of tachyons and orbifold flips described in hep-th/0412337, we study nonsupersymmetric analogs of the supersymmetric conifold singularity and show using their toric geometry description that they are nonsupersymmetric orbifolds of the latter. Using linear sigma models, we see that these are unstable to localized closed string tachyon condensation and exhibit flip transitions between their two small resolutions (involving 2-cycles), in the process mediating mild dynamical topology change. Our analysis shows that the structure of these nonsupersymmetric conifolds as quotients of the supersymmetric conifold obstructs the 3-cycle deformation of such singularities, suggesting that these nonsupersymmetric conifolds decay by evolving towards their stable small resolutions.Comment: Latex, 22 pgs, 2 figs. v4: matches JHEP version, 29 pgs, 3 figures, more elaborate Introduction, various clarifications adde

    Holographic dual of the Standard Model on the throat

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    We apply recent techniques to construct geometries, based on local Calabi-Yau manifolds, leading to warped throats with 3-form fluxes in string theory, with interesting structure at their bottom. We provide their holographic dual description in terms of RG flows for gauge theories with almost conformal duality cascades and infrared confinement. We describe a model of a throat with D-branes at its bottom, realizing a 3-family Standard Model like chiral sector. We provide the explicit holographic dual gauge theory RG flow, and describe the appearance of the SM degrees of freedom after confinement. As a second application, we describe throats within throats, namely warped throats with discontinuous warp factor in different regions of the radial coordinate, and discuss possible model building applications.Comment: 46 pages, 21 figures, reference adde

    On Type II Strings in Two Dimensions

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    We consider type IIA/B strings in two-dimensions and their projection with respect to the nilpotent space-time supercharge. Based on the ground ring structure, we propose a duality between perturbed type II strings and the topological B-model on deformed Calabi-Yau singularities. Depending on the type II spectra, one has either the conifold or the suspended pinch point geometry. Using the corresponding quiver gauge theory, obtained by D-branes wrapping in the resolved suspended pinch point geometry, we propose the all orders perturbative partition function.Comment: 1+23 page

    Ricci-flat deformation of orbifolds and localized tachyonic modes

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    We study Ricci-flat deformations of orbifolds in type II theory. We obtain a simple formula for mass corrections to the twisted modes due to the deformations, and apply it to originally tachyonic and massless states in several examples. In the case of supersymmetric orbifolds, we find that tachyonic states appear when the deformation breaks all the supersymmetries. We also study nonsupersymmetric orbifolds C^2/Z_{2N(2N+1)}, which is T-dual to N type 0 NS5-branes. For N>=2, we compute mass corrections for states, which have string scale tachyonic masses. We find that the corrected masses coincide to ones obtained by solving the wave equation for the tachyon field in the smeared type 0 NS5-brane background geometry. For N=1, we show that the unstable mode representing the bubble creation is the unique tachyonic mode.Comment: 20 pages, minor collection

    Spontaneous magnetization above TC in polycrystalline La0.7 Ca0.3 MnO3 and La0.7 Ba0.3 MnO3

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    In the present work, spontaneous magnetization is observed in the inverse magnetic susceptibility of La0.7Ca0.3MnO3 and La0.7Ba0.3MnO3 compounds above TC up to a temperature T*. From information gathered from neutron diffraction, dilatometry, and high-field magnetization data, we suggest that T* is related to the transition temperature of the low-temperature (high magnetic field) magnetic phase. In the temperature region between T* and TC, the application of a magnetic field drives the system from the high-temperature to low-temperature magnetic phases, the latter possessing a higher magnetization. © 2014 American Physical Society

    Structure and dynamics of Rh surfaces

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    Lattice relaxations, surface phonon spectra, surface energies, and work functions are calculated for Rh(100) and Rh(110) surfaces using density-functional theory and the full-potential linearized augmented plane wave method. Both, the local-density approximation and the generalized gradient approximation to the exchange-correlation functional are considered. The force constants are obtained from the directly calculated atomic forces, and the temperature dependence of the surface relaxation is evaluated by minimizing the free energy of the system. The anharmonicity of the atomic vibrations is taken into account within the quasiharmonic approximation. The importance of contributions from different phonons to the surface relaxation is analyzed.Comment: 9 pages, 7 figures, scheduled to appear in Phys. Rev. B, Feb. 15 (1998). Other related publications can be found at http://www.rz-berlin.mpg.de/th/paper.htm
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