242 research outputs found

    Recruiting and retaining children and families' social workers. The potential of work discussion groups

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    Current difficulties with the recruitment and retention of children and families' social workers have been formally acknowledged. However, although initiatives which focus on remuneration and career progression are clearly welcome, research and evidence from practice highlights how social workers themselves place high value on the availability of good quality supervision. Yet, questions remain about whether first-line managers have the time or are even in the best position to offer this support. This article draws on the experience and evaluation of one particular model of supervision — 'work discussion groups' —and explores its impact with residential social work staff and teachers as well as the potential for further developments of this kind

    Spin Dynamics of the Triangular Heisenberg Antiferromagnet: A Schwinger Boson Approach

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    We have analyzed the two-dimensional antiferromagnetic Heisenberg model on the triangular lattice using a Schwinger boson mean-field theory. By expanding around a state with local 120∘120^\circ order, we obtain, in the limit of infinite spin, results for the excitation spectrum in complete agreement with linear spin wave theory (LSWT). In contrast to LSWT, however, the modes at the ordering wave vectors acquire a mass for finite spin. We discuss the origin of this effect.Comment: 15 pages REVTEX 3.0 preprint, 6 postscript figures ( uuencoded and compressed using the script uufiles ) are submitted separately

    Possible Quantum Spin Liquid States on the Triangular and Kagome Lattices

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    The frustrated spin-one-half Heisenberg model on triangualr and Kagome Lattices is mapped onto a single specis of fermion carrying statistical flux. The corresponding Chern-Simons gauge theory is analyzed at the Gaussian level and found to be massive. This provides a new motivation for the spin-liquid Kalmeyer-Laughlin wave function. Good overlap of this wave function with the numerical ground state is found for small clusters.Comment: 13 pages, revtex. IUCM-920

    Spontaneous Inter-layer Coherence in Double-Layer Quantum-Hall Systems I: Charged Vortices and Kosterlitz-Thouless Phase Transitions

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    At strong magnetic fields double-layer two-dimensional-electron-gas systems can form an unusual broken symmetry state with spontaneous inter-layer phase coherence. In this paper we explore the rich variety of quantum and finite-temperature phase transitions associated with this broken symmetry. We describe the system using a pseudospin language in which the layer degree-of-freedom is mapped to a fictional spin 1/2 degree-of-freedom. With this mapping the spontaneous symmetry breaking is equivalent to that of a spin 1/2 easy-plane ferromagnet. In this language spin-textures can carry a charge. In particular, vortices carry e/2 electrical charge and vortex-antivortex pairs can be neutral or carry charge e. We derive an effective low-energy action and use it to discuss the charged and collective neutral excitations of the system. We have obtained the parameters of the Landau-Ginzburg functional from first-principles estimates and from finite-size exact diagonalization studies. We use these results to estimate the dependence of the critical temperature for the Kosterlitz-Thouless phase transition on layer separation.Comment: 56 pages, 19 figures available upon request at [email protected]. RevTex 3.0. IUCM94-00

    Self-esteem is associated with premorbid adjustment and positive psychotic symptoms in early psychosis

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    <p>Abstract</p> <p>Background</p> <p>Low levels of self-esteem have been implicated as both a cause and a consequence of severe mental disorders. The main aims of the study were to examine whether premorbid adjustment has an impact on the subject's self-esteem, and whether lowered self-esteem contributes to the development of delusions and hallucinations.</p> <p>Method</p> <p>A total of 113 patients from the Thematically Organized Psychosis research study (TOP) were included at first treatment. The Positive and Negative Syndrome Scale (PANSS) was used to assess present symptoms. Premorbid adjustment was measured with the Premorbid Adjustment Scale (PAS) and self-esteem by the Rosenberg Self-Esteem Scale (RSES).</p> <p>Results</p> <p>Premorbid social adjustment was significantly related to lower self-esteem and explained a significant proportion of the variance in self-esteem. Self-esteem was significantly associated with the levels of persecutory delusions and hallucinations experienced by the patient and explained a significant proportion of the variance even after adjusting for premorbid functioning and depression.</p> <p>Conclusion</p> <p>There are reasons to suspect that premorbid functioning is an important aspect in the development of self- esteem, and, furthermore, that self-esteem is associated with the development of delusions and hallucinations.</p

    New-generation atrial antitachycardia pacing (Reactive ATP) is associated with reduced risk of persistent or permanent atrial fibrillation in patients with bradycardia: Results from the MINERVA randomized multicenter international trial

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    Background Atrial fibrillation (AF) is a frequent comorbidity in patients with pacemaker and is a recognized cause of mortality, morbidity, and quality-of-life impairment. The international MINimizE Right Ventricular pacing to prevent Atrial fibrillation and heart failure trial established that atrial preventive pacing and atrial antitachycardia pacing (DDDRP) in combination with managed ventricular pacing (MVP) reduce permanent AF occurrence in comparison with standard dual-chamber pacing (DDDR). Objective We aimed to determine the role of new-generation atrial antitachycardia pacing (Reactive ATP) in preventing AF disease progression. Methods Patients with dual-chamber pacemaker and with previous atrial tachyarrhythmias were randomly assigned to DDDR (n = 385 (33%)), MVP (n = 398 (34%)), or DDDRP+MVP (n = 383 (33%)) group. The incidence of permanent AF, as defined by the study investigator, or persistent AF, defined as ≥7 consecutive days with AF, was estimated using the Kaplan-Meier method, while its association with patients' characteristics was evaluated via multivariable Cox regression. Results At 2 years, the incidence of permanent or persistent AF was 26% (95% confidence interval [CI] 22%-31%) in the DDDR group, 25% (95% CI 21%-30%) in the MVP group, and 15% (95% CI 12%-20%) in the DDDRP+MVP group (P 44.4%) as a significant predictor of reduced permanent or persistent AF risk (hazard ratio 0.32; 95% CI 0.13-0.781; P =.012) and episodes' characteristics, such as long atrial arrhythmia cycle length, regularity, and the number of rhythm transitions, as predictors of high ATP efficacy. Conclusion In patients with bradycardia, DDDRP+MVP delays AF disease progression, with Reactive ATP efficacy being an independent predictor of permanent or persistent AF reduction

    Computational Study of Hippocampal-Septal Theta Rhythm Changes Due to Beta-Amyloid-Altered Ionic Channels

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    Electroencephagraphy (EEG) of many dementia patients has been characterized by an increase in low frequency field potential oscillations. One of the characteristics of early stage Alzheimer’s disease (AD) is an increase in theta band power (4–7 Hz). However, the mechanism(s) underlying the changes in theta oscillations are still unclear. To address this issue, we investigate the theta band power changes associated with β-Amyloid (Aβ) peptide (one of the main markers of AD) using a computational model, and by mediating the toxicity of hippocampal pyramidal neurons. We use an established biophysical hippocampal CA1-medial septum network model to evaluate four ionic channels in pyramidal neurons, which were demonstrated to be affected by Aβ. They are the L-type Ca2+ channel, delayed rectifying K+ channel, A-type fast-inactivating K+ channel and large-conductance Ca2+-activated K+ channel. Our simulation results demonstrate that only the Aβ inhibited A-type fast-inactivating K+ channel can induce an increase in hippocampo-septal theta band power, while the other channels do not affect theta rhythm. We further deduce that this increased theta band power is due to enhanced synchrony of the pyramidal neurons. Our research may elucidate potential biomarkers and therapeutics for AD. Further investigation will be helpful for better understanding of AD-induced theta rhythm abnormalities and associated cognitive deficits
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