20,286 research outputs found

    The Availability of Training Opportunities in Personality Disorders in American Psychological Association- and Psychological Clinical Science Accreditation System-Accredited Clinical and Counseling Psychology Doctoral Programs

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    Personality disorders are relatively common, especially in clinical settings. A number of evidence-based treatments are now available, especially for borderline personality disorder. However, little is known about the relevant training available to doctoral students in clinical and counseling psychology. in the current study, data were extracted from 336 clinical and counseling Ph.D. and Psy.D. programs from the Insider’s Guide to Graduate Programs in Clinical and Counseling Psychology (Norcross & Sayette, 2020), including the number of programs with faculty with specific interests in personality disorders and the number of programs with clinical opportunities related to personality disorders. We found that formal training in personality disorders is not widely available to most trainees in APA-accredited doctoral training programs. Only 16% of programs have faculty with interests in personality disorders, all of them clinical psychology programs. Ph.D. programs were more likely to have PD-interested faculty than Psy.D. programs, and, within clinical Ph.D. programs, PCSAS-accredited programs were more likely to have PD-interested faculty than programs without PCSAS accreditation. Similarly, only 15% of programs (all clinical psychology programs) offer practicum opportunities in psychotherapy for personality disorders. Our findings indicate that doctoral level psychology programs are not sufficiently preparing their students with personality disorder training, which serves as a substantial disservice to both trainees and the public

    Thermodynamics as an alternative foundation for zero-temperature density functional theory and spin density functional theory

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    Thermodynamics provides a transparent definition of the free energy of density functional theory (DFT), and of its derivatives - the potentials, at finite temperatures T. By taking the T to 0 limit, it is shown here that both DFT and spin-dependent DFT (for ground states) suffer from precisely the same benign ambiguities: (a) charge and spin quantization lead to "up to a constant" indeterminacies in the potential and the magnetic field respectively, and (b) the potential in empty subspaces is undetermined but irrelevant. Surprisingly, these simple facts were inaccessible within the standard formulation, leading to recent discussions of apparent difficulties within spin-DFT.Comment: RevTeX, to appear in Phys. Rev.

    Center of mass and relative motion in time dependent density functional theory

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    It is shown that the exchange-correlation part of the action functional Axc[ρ(r,t)]A_{xc}[\rho (\vec r,t)] in time-dependent density functional theory , where ρ(r,t)\rho (\vec r,t) is the time-dependent density, is invariant under the transformation to an accelerated frame of reference ρ(r,t)ρ(r,t)=ρ(r+x(t),t)\rho (\vec r,t) \to \rho ' (\vec r,t) = \rho (\vec r + \vec x (t),t), where x(t)\vec x (t) is an arbitrary function of time. This invariance implies that the exchange-correlation potential in the Kohn-Sham equation transforms in the following manner: Vxc[ρ;r,t]=Vxc[ρ;r+x(t),t]V_{xc}[\rho '; \vec r, t] = V_{xc}[\rho; \vec r + \vec x (t),t]. Some of the approximate formulas that have been proposed for VxcV_{xc} satisfy this exact transformation property, others do not. Those which transform in the correct manner automatically satisfy the ``harmonic potential theorem", i.e. the separation of the center of mass motion for a system of interacting particles in the presence of a harmonic external potential. A general method to generate functionals which possess the correct symmetry is proposed

    Volatility clustering and scaling for financial time series due to attractor bubbling

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    A microscopic model of financial markets is considered, consisting of many interacting agents (spins) with global coupling and discrete-time thermal bath dynamics, similar to random Ising systems. The interactions between agents change randomly in time. In the thermodynamic limit the obtained time series of price returns show chaotic bursts resulting from the emergence of attractor bubbling or on-off intermittency, resembling the empirical financial time series with volatility clustering. For a proper choice of the model parameters the probability distributions of returns exhibit power-law tails with scaling exponents close to the empirical ones.Comment: For related publications see http://www.helbing.or

    Local Ferroelectricity in SrTiO_3 Thin Films

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    The temperature-dependent polarization of SrTiO_3 thin films is investigated using confocal scanning optical microscopy. A homogeneous out-of-plane and inhomogeneous in-plane ferroelectric phase are identified from images of the linear electrooptic response. Both hysteretic and non-hysteretic behavior are observed under a dc bias field. Unlike classical transitions in bulk ferroelectrics, local ferroelectricity is observed at temperatures far above the dielectric permittivity maximum. The results demonstrate the utility of local probe experiments in understanding inhomogeneous ferroelectrics.Comment: 8 pages, 3 figures, accepted for publication in PR

    Ultrasound Investigations of Orbital Quadrupolar Ordering in UPd_3

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    For a high-quality single crystal of UPd_3 we present the relevant elastic constants and ultrasonic attenuation data. In addition to the magnetic phase transition at T_2=4.4 +/- 0.1K and the quadrupolar transition at T_1~6.8K, we find orbital ordering at T_0=7.6 +/- 0.1K concomitant with a symmetry change from hexagonal to orthorhombic. A striking feature is the splitting of the phase transition at T_1 into a second-order transition at T_{+1}=6.9 +/- 0.05K and a first-order transition at T_{-1}=6.7 +/- 0.05K. For the four phase transitions, the quadrupolar order parameters and the respective symmetry changes are specified.Comment: 14 pages (RevTex), 3 eps-figures, accepted by PR

    Exploring Foundations of Time-Independent Density Functional Theory for Excited-States

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    Based on the work of Gorling and that of Levy and Nagy, density-functional formalism for many Fermionic excited-states is explored through a careful and rigorous analysis of the excited-state density to external potential mapping. It is shown that the knowledge of the ground-state density is a must to fix the mapping from an excited-state density to the external potential. This is the excited-state counterpart of the Hohenberg-Kohn theorem, where instead of the ground-state density the density of the excited-state gives the true many-body wavefunctions of the system. Further, the excited-state Kohn-Sham system is defined by comparing it's non-interacting kinetic energy with the true kinetic energy. The theory is demonstrated by studying a large number of atomic systems.Comment: submitted to J. Chem. Phy

    On-chip non-reciprocal optical devices based on quantum inspired photonic lattices

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    We propose a novel geometry for integrated photonic devices that can be used as isolators and polarization splitters based on engineered photonic lattices. Starting from optical waveguide arrays that mimic Fock space representation of a non-interacting two-site Bose Hubbard Hamiltonian, we show that introducing magneto-optic nonreciprocity to these structures leads to a superior optical isolation performance. In the forward propagation direction, an input TM polarized beam experiences a perfect state transfer between the input and output waveguide channels while surface Bloch oscillations block the backward transmission between the same ports. Our analysis indicates a large isolation ratio of 75 dB after a propagation distance of 8 mm inside seven coupled waveguides. Moreover, we demonstrate that, a judicious choice of the nonreciprocity in this same geometry can lead to perfect polarization splitting.Comment: 13 pages 3 figure

    Surface Enhancement of Superconductivity in Tin

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    The possibility of surface enhancement of superconductivity is examined experimentally. It is shown that single crystal tin samples with cold-worked surfaces represent a superconductor with a surface-enhanced order parameter (or negative surface extrapolation length b), whose magnitude can be controlled.Comment: 8 pages, 4 figure
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