389 research outputs found

    Vicarious experience affects patients' treatment preferences for depression

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    Purpose: Depression is common in primary care but often under-treated. Personal experiences with depression can affect adherence to therapy, but the effect of vicarious experience is unstudied. We sought to evaluate the association between a patient's vicarious experiences with depression (those of friends or family) and treatment preferences for depressive symptoms. Methods: We sampled 1054 English and/or Spanish speaking adult subjects from July through December 2008, randomly selected from the 2008 California Behavioral Risk Factor Survey System, regarding depressive symptoms and treatment preferences. We then constructed a unidimensional scale using item analysis that reflects attitudes about antidepressant pharmacotherapy. This became the dependent variable in linear regression analyses to examine the association between vicarious experiences and treatment preferences for depressive symptoms. Results: Our sample was 68% female, 91% white, and 13% Hispanic. Age ranged from 18-94 years. Mean PHQ-9 score was 4.3; 14.5% of respondents had a PHQ-9 score >9.0, consistent with active depressive symptoms. Analyses controlling for current depression symptoms and socio-demographic factors found that in patients both with (coefficient 1.08, p = 0.03) and without (coefficient 0.77, p = 0.03) a personal history of depression, having a vicarious experience (family and friend, respectively) with depression is associated with a more favorable attitude towards antidepressant medications. Conclusions: Patients with vicarious experiences of depression express more acceptance of pharmacotherapy. Conversely, patients lacking vicarious experiences of depression have more negative attitudes towards antidepressants. When discussing treatment with patients, clinicians should inquire about vicarious experiences of depression. This information may identify patients at greater risk for non-adherence and lead to more tailored patient-specific education about treatment

    Effectiveness of CFD simulation for the performance prediction of phase change building boards in the thermal environment control of indoor spaces

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    This is the post-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2013 ElsevierThis paper reports on a validation study of CFD models used to predict the effect of PCM clay boards on the control of indoor environments, in ventilated and non-ventilated situations. Unlike multi-zonal models, CFD is important in situations where localised properties are essential such as in buildings with complex and large geometries. The employed phase change model considers temperature/enthalpy hysteresis and varying enthalpy-temperature characteristics to more accurately simulate the phase change behaviour of the PCM boards compared to the standard default modelling approach in the commercial CFD codes. Successful validation was obtained with a mean error of 1.0 K relative to experimental data, and the results show that in addition to providing satisfactory quantitative results, CFD also provides qualitative results which are useful in the effective design of indoor thermal environment control systems utilising PCM. These results include: i) temperature and air flow distribution within the space resulting from the use of PCM boards and different night ventilation rates; ii) the fraction of PCM experiencing phase change and is effective in the control of the indoor thermal environment, enabling optimisation of the location of the boards; and iii) the energy impact of PCM boards and adequate ventilation configurations for effective night charging.This work was funded through sponsorship from the UK Engineering and Physical Sciences Research Council (EPSRC), Grant No: EP/H004181/1

    Dual Vortex Theory of Strongly Interacting Electrons: Non-Fermi Liquid to the (Hard) Core

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    As discovered in the quantum Hall effect, a very effective way for strongly-repulsive electrons to minimize their potential energy is to aquire non-zero relative angular momentum. We pursue this mechanism for interacting two-dimensional electrons in zero magnetic field, by employing a representation of the electrons as composite bosons interacting with a Chern-Simons gauge field. This enables us to construct a dual description in which the fundamental constituents are vortices in the auxiliary boson fields. The resulting formalism embraces a cornucopia of possible phases. Remarkably, superconductivity is a generic feature, while the Fermi liquid is not -- prompting us to conjecture that such a state may not be possible when the interactions are sufficiently strong. Many aspects of our earlier discussions of the nodal liquid and spin-charge separation find surprising incarnations in this new framework.Comment: Modified dicussion of the hard-core model, correcting several mistake

    Instability, Intermixing and Electronic Structure at the Epitaxial LaAlO3/SrTiO3(001) Heterojunction

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    The question of stability against diffusional mixing at the prototypical LaAlO3/SrTiO3(001) interface is explored using a multi-faceted experimental and theoretical approach. We combine analytical methods with a range of sensitivities to elemental concentrations and spatial separations to investigate interfaces grown using on-axis pulsed laser deposition. We also employ computational modeling based on the density function theory as well as classical force fields to explore the energetic stability of a wide variety of intermixed atomic configurations relative to the idealized, atomically abrupt model. Statistical analysis of the calculated energies for the various configurations is used to elucidate the relative thermodynamic stability of intermixed and abrupt configurations. We find that on both experimental and theoretical fronts, the tendency toward intermixing is very strong. We have also measured and calculated key electronic properties such as the presence of electric fields and the value of the valence band discontinuity at the interface. We find no measurable electric field in either the LaAlO3 or SrTiO3, and that the valence band offset is near zero, partitioning the band discontinuity almost entirely to the conduction band edge. Moreover, we find that it is not possible to account for these electronic properties theoretically without including extensive intermixing in our physical model of the interface. The atomic configurations which give the greatest electrostatic stability are those that eliminate the interface dipole by intermixing, calling into question the conventional explanation for conductivity at this interface - electronic reconstruction. Rather, evidence is presented for La indiffusion and doping of the SrTiO3 below the interface as being the cause of the observed conductivity

    Can chaotic quantum energy levels statistics be characterized using information geometry and inference methods?

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    In this paper, we review our novel information geometrodynamical approach to chaos (IGAC) on curved statistical manifolds and we emphasize the usefulness of our information-geometrodynamical entropy (IGE) as an indicator of chaoticity in a simple application. Furthermore, knowing that integrable and chaotic quantum antiferromagnetic Ising chains are characterized by asymptotic logarithmic and linear growths of their operator space entanglement entropies, respectively, we apply our IGAC to present an alternative characterization of such systems. Remarkably, we show that in the former case the IGE exhibits asymptotic logarithmic growth while in the latter case the IGE exhibits asymptotic linear growth. At this stage of its development, IGAC remains an ambitious unifying information-geometric theoretical construct for the study of chaotic dynamics with several unsolved problems. However, based on our recent findings, we believe it could provide an interesting, innovative and potentially powerful way to study and understand the very important and challenging problems of classical and quantum chaos.Comment: 21 page

    Parity Violation in Proton-Proton Scattering

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    Measurements of parity-violating longitudinal analyzing powers (normalized asymmetries) in polarized proton-proton scattering provide a unique window on the interplay between the weak and strong interactions between and within hadrons. Several new proton-proton parity violation experiments are presently either being performed or are being prepared for execution in the near future: at TRIUMF at 221 MeV and 450 MeV and at COSY (Kernforschungsanlage Juelich) at 230 MeV and near 1.3 GeV. These experiments are intended to provide stringent constraints on the set of six effective weak meson-nucleon coupling constants, which characterize the weak interaction between hadrons in the energy domain where meson exchange models provide an appropriate description. The 221 MeV is unique in that it selects a single transition amplitude (3P2-1D2) and consequently constrains the weak meson-nucleon coupling constant h_rho{pp}. The TRIUMF 221 MeV proton-proton parity violation experiment is described in some detail. A preliminary result for the longitudinal analyzing power is Az = (1.1 +/-0.4 +/-0.4) x 10^-7. Further proton-proton parity violation experiments are commented on. The anomaly at 6 GeV/c requires that a new multi-GeV proton-proton parity violation experiment be performed.Comment: 13 Pages LaTeX, 5 PostScript figures, uses espcrc1.sty. Invited talk at QULEN97, International Conference on Quark Lepton Nuclear Physics -- Nonperturbative QCD Hadron Physics & Electroweak Nuclear Processes --, Osaka, Japan May 20--23, 199

    Acute viral bronchiolitis in South Africa : strategies for management and prevention

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    Management of acute viral bronchiolitis is largely supportive. There is currently no proven effective therapy other than oxygen for hypoxic children. The evidence indicates that there is no routine benefit from inhaled, rapid short-acting bronchodilators, adrenaline or ipratropium bromide for children with acute viral bronchiolitis. Likewise, there is no demonstrated benefit from routine use of inhaled or oral corticosteroids, inhaled hypertonic saline nebulisation, montelukast or antibiotics. The last should be reserved for children with severe disease, when bacterial co-infection is suspected. Prevention of respiratory syncytial virus (RSV) disease remains a challenge. A specific RSV monoclonal antibody, palivizumab, administered as an intramuscular injection, is available for children at risk of severe bronchiolitis, including premature infants, young children with chronic lung disease, immunodeficiency, or haemodynamically significant congenital heart disease. Prophylaxis should be commenced at the start of the RSV season and given monthly during the season. The development of an RSV vaccine may offer a more effective alternative to prevent disease, for which the results of clinical trials are awaited. Education of parents or caregivers and healthcare workers about diagnostic and management strategies should include the following: bronchiolitis is caused by a virus; it is seasonal; it may start as an upper respiratory tract infection with low-grade fever; symptoms are cough and wheeze, often with fast breathing; antibiotics are generally not needed; and the condition is usually self limiting, although symptoms may occur for up to 4 weeks in some children.http://www.samj.org.zaam2016Paediatrics and Child Healt

    Parity nonconserving cold neutron-parahydrogen interactions

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    Three pion dominated observables of the parity nonconserving interactions between the cold neutrons and parahydrogen are calculated. The transversely polarized neutron spin rotation, unpolarized neutron longitudinal polarization, and photon-asymmetry of the radiative polarized neutron capture are considered. For the numerical evaluation of the observables, the strong interactions are taken into account by the Reid93 potential and the parity nonconserving interactions by the DDH model along with the two-pion exchange.Comment: 17 pages, 2 figure

    On the nature of the finite-temperature transition in QCD

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    We discuss the nature of the finite-temperature transition in QCD with N_f massless flavors. Universality arguments show that a continuous (second-order) transition must be related to a 3-D universality class characterized by a complex N_f X N_f matrix order parameter and by the symmetry-breaking pattern [SU(N_f)_L X SU(N_f)_R]/Z(N_f)_V -> SU(N_f)_V/Z(N_f)_V, or [U(N_f)_L X U(N_f)_R]/U(1)_V -> U(N_f)_V/U(1)_V if the U(1)_A symmetry is effectively restored at T_c. The existence of any of these universality classes requires the presence of a stable fixed point in the corresponding 3-D Phi^4 theory with the expected symmetry-breaking pattern. Otherwise, the transition is of first order. In order to search for stable fixed points in these Phi^4 theories, we exploit a 3-D perturbative approach in which physical quantities are expanded in powers of appropriate renormalized quartic couplings. We compute the corresponding Callan-Symanzik beta-functions to six loops. We also determine the large-order behavior to further constrain the analysis. No stable fixed point is found, except for N_f=2, corresponding to the symmetry-breaking pattern [SU(2)_L X SU(2)_R]/Z(2)_V -> SU(2)_V/Z(2)_V equivalent to O(4) -> O(3). Our results confirm and put on a firmer ground earlier analyses performed close to four dimensions, based on first-order calculations in the framework of the epsilon=4-d expansion. These results indicate that the finite-temperature phase transition in QCD is of first order for N_f>2. A continuous transition is allowed only for N_f=2. But, since the theory with symmetry-breaking pattern [U(2)_L X U(2)_R]/U(1)_V -> U(2)_V/U(1)_V does not have stable fixed points, the transition can be continuous only if the effective breaking of the U(1)_A symmetry is sufficiently large.Comment: 30 pages, 3 figs, minor correction
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