2,979 research outputs found

    Group psychoeducative cognitive-behaviour therapy for mixed anxiety and depression with older adults

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    Objectives: There is a dearth of older adult evidence regarding the group treatment for co-morbid anxiety and depression. This research evaluated the effectiveness of a low-intensity group psychoeducational approach. Method: Patients attended six sessions of a manualised cognitive-behavioural group. Validated measures of anxiety, depression and psychological well-being were taken at assessment, termination and six-week follow-up from patients, who also rated the alliance and their anxiety/depression at each group session. Staff rated patients regarding their functioning at assessment, termination and six-week follow-up. Outcomes were categorised according to whether patients had recovered, improved, deteriorated or been harmed. Effect sizes were compared to extant group interventions for anxiety and depression. Results: Eight groups were completed with 34 patients, with a drop-out rate of 17%. Staff and patient rated outcome measures showed significant improvements (with small effect sizes) in assessment to termination and assessment to follow-up comparisons. Over one quarter (26.47%) of patients met the recovery criteria at follow-up and no patients were harmed. Outcomes for anxiety were better than for depression with the alliance in groups stable over time. Conclusion: The intervention evaluated shows clinical and organisational promise. The group approach needs to be further developed and tested in research with greater methodological control

    Therapist effects and IAPT Psychological Wellbeing Practitioners (PWPs): A multilevel modelling and mixed methods analysis

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    The aim of this research was (a) to determine the extent of therapist effects in Psychological Wellbeing Practitioners (PWPs) delivering guided self-help in IAPT services and (b) to identify factors that defined effective PWP clinical practice. Using patient (N = 1122) anxiety and depression outcomes (PHQ-9 and GAD-7), the effectiveness of N = 21 PWPs across 6 service sites was examined using multi-level modelling. PWPs and their clinical supervisors were also interviewed and completed measures of ego strength, intuition and resilience. Therapist effects accounted for around 9 per cent of the variance in patient outcomes. One PWP had significantly better than average outcomes on both PHQ-9 and GAD-7 while 3 PWPs were significantly below average on the PHQ-9 and 2 were below average on the GAD-7. Computed PWP ranks identified quartile clusters of the most (N = 5) and least (N = 5) effective PWPs. More effective PWPs generated higher rates of reliable and clinically significant change and displayed greater resilience, organisational abilities, knowledge and confidence. Study weaknesses are identified and methodological considerations for future studies examining therapist effects in low intensity cognitive behaviour therapy are provided

    Rydberg Wave Packets are Squeezed States

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    We point out that Rydberg wave packets (and similar ``coherent" molecular packets) are, in general, squeezed states, rather than the more elementary coherent states. This observation allows a more intuitive understanding of their properties; e.g., their revivals.Comment: 7 pages of text plus one figure available in the literature, LA-UR 93-2804, to be published in Quantum Optics, LaTe

    Exact results for `bouncing' Gaussian wave packets

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    We consider time-dependent Gaussian wave packet solutions of the Schrodinger equation (with arbitrary initial central position, x_0, and momentum, p_0, for an otherwise free-particle, but with an infinite wall at x=0, so-called bouncing wave packets. We show how difference or mirror solutions of the form psi(x,t)-psi(-x,t) can, in this case, be normalized exactly, allowing for the evaluation of a number of time-dependent expectation values and other quantities in closed form. For example, we calculate _t explicitly which illustrates how the free-particle kinetic (and hence total) energy is affected by the presence of the distant boundary. We also discuss the time dependence of the expectation values of position, _t, and momentum, _t, and their relation to the impulsive force during the `collision' with the wall. Finally, the x_0,p_0 --> 0 limit is shown to reduce to a special case of a non-standard free-particle Gaussian solution. The addition of this example to the literature then expands on the relatively small number of Gaussian solutions to quantum mechanical problems with familiar classical analogs (free particle, uniform acceleration, harmonic oscillator, unstable oscillator, and uniform magnetic field) available in closed form.Comment: 14 pages, 1 embedded .eps figur

    The Stark effect in linear potentials

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    We examine the Stark effect (the second-order shift in the energy spectrum due to an external constant force) for two 1-dimensional model quantum mechanical systems described by linear potentials, the so-called quantum bouncer (defined by V(z) = Fz for z>0 and V(z) infinite for z<0) and the symmetric linear potential (given by V(z) = F|z|). We show how straightforward use of the most obvious properties of the Airy function solutions and simple Taylor expansions give closed form results for the Stark shifts in both systems. These exact results are then compared to other approximation techniques, such as perturbation theory and WKB methods. These expressions add to the small number of closed-form descriptions available for the Stark effect in model quantum mechanical systems.Comment: 15 pages. To appear in Eur. J. Phys. Needs Institute of Physics (iopart) style file

    A systematic review of therapist effects: A critical narrative update and refinement to Baldwin and Imel's (2013) review

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    Objective: To review the therapist effects literature since Baldwin and Imel's (2013) review. Method: Systematic literature review of three databases (PsycINFO, PubMed and Web of Science) replicating Baldwin and Imel (2013) search terms. Weighted averages of therapist effects (TEs) were calculated, and a critical narrative review of included studies conducted. Results: Twenty studies met inclusion criteria (3 RCTs; 17 practice-based) with 19 studies using multilevel modeling. TEs were found in 19 studies. The TE range for all studies was 0.2% to 29% (weighted average = 5%). For RCTs, 1%–29% (weighted average = 8.2%). For practice-based studies, 0.2–21% (weighted average = 5%). The university counseling subsample yielded a lower TE (2.4%) than in other groupings (i.e., primary care, mixed clinical settings, and specialist/focused settings). Therapist sample sizes remained lower than recommended, and few studies appeared to be designed specifically as TE studies as opposed to maximising on the availability of large routine patient datasets. Conclusions: Therapist effects are a robust phenomenon although considerable heterogeneity exists across studies. Patient severity appeared related to TE size. TEs from RCTs were highly variable. Using an overall therapist effects statistic may lack precision, and TEs might be better reported separately for specific clinical settings

    Strange Decays of Nonstrange Baryons

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    The strong decays of excited nonstrange baryons into the final states Lambda K, Sigma K, and for the first time into Lambda(1405) K, Lambda(1520) K, Sigma(1385) K, Lambda K*, and Sigma K*, are examined in a relativized quark pair creation model. The wave functions and parameters of the model are fixed by previous calculations of N pi and N pi pi, etc., decays. Our results show that it should be possible to discover several new negative parity excited baryons and confirm the discovery of several others by analyzing these final states in kaon production experiments. We also establish clear predictions for the relative strengths of certain states to decay to Lambda(1405) K and Lambda(1520) K, which can be tested to determine if a three-quark model of the Lambda(1405) K is valid. Our results compare favorably with the results of partial wave analyses of the limited existing data for the Lambda K and Sigma K channels. We do not find large Sigma K decay amplitudes for a substantial group of predicted and weakly established negative-parity states, in contrast to the only previous work to consider decays of these states into the strange final states Lambda K and Sigma K.Comment: 25 pages, 8 figures, RevTe

    Eikonal analysis of Coulomb distortion in quasi-elastic electron scattering

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    An eikonal expansion is used to provide systematic corrections to the eikonal approximation through order 1/k21/k^2, where kk is the wave number. Electron wave functions are obtained for the Dirac equation with a Coulomb potential. They are used to investigate distorted-wave matrix elements for quasi-elastic electron scattering from a nucleus. A form of effective-momentum approximation is obtained using trajectory-dependent eikonal phases and focusing factors. Fixing the Coulomb distortion effects at the center of the nucleus, the often-used ema approximation is recovered. Comparisons of these approximations are made with full calculations using the electron eikonal wave functions. The ema results are found to agree well with the full calculations.Comment: 12 pages, 6 Postscript figure

    Analytic results for Gaussian wave packets in four model systems: I. Visualization of the kinetic energy

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    Using Gaussian wave packet solutions, we examine how the kinetic energy is distributed in time-dependent solutions of the Schrodinger equation corresponding to the cases of a free particle, a particle undergoing uniform acceleration, a particle in a harmonic oscillator potential, and a system corresponding to an unstable equilibrium. We find, for specific choices of initial parameters, that as much as 90% of the kinetic energy can be localized (at least conceptually) in the `front half' of such Gaussian wave packets, and we visualize these effects.Comment: 22 pages, RevTeX, four .eps figures, to appear in Found. Phys. Lett. Vol. 17, Dec. 200

    Weak localization of light by cold atoms: the impact of quantum internal structure

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    Since the work of Anderson on localization, interference effects for the propagation of a wave in the presence of disorder have been extensively studied, as exemplified in coherent backscattering (CBS) of light. In the multiple scattering of light by a disordered sample of thermal atoms, interference effects are usually washed out by the fast atomic motion. This is no longer true for cold atoms where CBS has recently been observed. However, the internal structure of the atoms strongly influences the interference properties. In this paper, we consider light scattering by an atomic dipole transition with arbitrary degeneracy and study its impact on coherent backscattering. We show that the interference contrast is strongly reduced. Assuming a uniform statistical distribution over internal degrees of freedom, we compute analytically the single and double scattering contributions to the intensity in the weak localization regime. The so-called ladder and crossed diagrams are generalized to the case of atoms and permit to calculate enhancement factors and backscattering intensity profiles for polarized light and any closed atomic dipole transition.Comment: 22 pages Revtex, 9 figures, to appear in PR
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