143 research outputs found

    Quantum-to-classical crossover for Andreev billiards in a magnetic field

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    We extend the existing quasiclassical theory for the superconducting proximity effect in a chaotic quantum dot, to include a time-reversal-symmetry breaking magnetic field. Random-matrix theory (RMT) breaks down once the Ehrenfest time τE\tau_E becomes longer than the mean time τD\tau_D between Andreev reflections. As a consequence, the critical field at which the excitation gap closes drops below the RMT prediction as τE/τD\tau_E/\tau_D is increased. Our quasiclassical results are supported by comparison with a fully quantum mechanical simulation of a stroboscopic model (the Andreev kicked rotator).Comment: 11 pages, 10 figure

    Presentation and validation of the Abbreviated Self Completion Teen-Addiction Severity Index (ASC T-ASI): A preference-based measure for use in health-economic evaluations

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    Economic evaluations of new youth mental health interventions require preference-based outcome measures that capture the broad benefits these interventions can have for adolescents. The Abbreviated Self Completion Teen-Addiction Severity Index (ASC T-ASI) was developed to meet the need for such a broader measure. It assesses self reported problems in seven important domains of adolescents’ lives, including school performance and family relationships, an

    Cost-effectiveness of blended vs. face-to-face cognitive behavioural therapy for severe anxiety disorders: study protocol of a randomized controlled trial

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    Background: Anxiety disorders are among the most prevalent psychiatric conditions, and are associated with poor quality of life and substantial economic burden. Cognitive behavioural therapy is an effective treatment to reduce anxiety symptoms, but is also costly and labour intensive. Cost-effectiveness could possibly be improved by delivering cognitive behavioural therapy in a blended format, where face-to-face sessions are partially replaced by online sessions. The aim of this trial is to determine the cost-effectiveness of blended cognitive behavioural therapy for adults with anxiety disorders, i.e. panic disorder, social phobia or generalized anxiety disorder, in specialized mental health care settings compared to face-to-face cognitive behavioural therapy. In this paper, we present the study protocol. It is hypothesized that blended cognitive behavioural therapy for anxiety disorders is clinically as effective as face-to-face cognitive behavioural therapy, but that intervention costs may be reduced. We thus hypothesize that blended cognitive behavioural therapy is more cost-effective than face-to-face cognitive behavioural therapy. Methods/design: In a randomised controlled equivalence trial 156 patients will be included (n = 78 in blended cognitive behavioural therapy, n = 78 in face-to-face cognitive behavioural therapy) based on a power of 0.80, calculated by using a formula to estimate the power of a cost-effectiveness analysis: n=2(zα+zβ)2(sd2+(W2sd2)(2Wpsdcsdq))(WEC)2n = \frac{2(z_\alpha + z_\beta)^2(sd^2 + (W^2sd^2) - (2Wpsd_csd_q))}{(WE-C)^2} Measurements will take place at baseline, midway treatment (7 weeks), immediately after treatment (15 weeks) and 12-month follow-up. At baseline a diagnostic interview will be administered. Primary clinical outcomes are changes in anxiety symptom severity as measured with the Beck Anxiety Inventory. An incremental cost-effectiveness ratio will be calculated to obtain the costs per quality-adjusted life years (QALYs) measured by the EQ-5D (5-level version). Health-economic outcomes will be explored from a societal and health care perspective. Discussion: This trial will be one of the first to provide information on the cost-effectiveness of blended cognitive behavioural therapy for anxiety disorders in routine specialized mental health care settings, both from a societal and a health care perspective

    Indicators of patients with major depressive disorder in need of highly specialized care: A systematic review

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    Objectives Early identification of patients with major depressive disorder (MDD) that cannot be managed by secondary mental health services and who require highly specialized mental healthcare could enhance need-based patient stratification. This, in turn, may reduce the number of treatment steps needed to achieve and sustain an adequate treatment response. The development of a valid tool to identify patients with MDD in need of highly specialized care is hampered by the lack of a comprehensive understanding of indicators that distinguish patients with and without a need for highly specialized MDD care. The aim of this study, therefore, was to systematically review studies on indicators of patients with MDD likely in need of highly specialized care. Methods A structured literature search was performed on the PubMed and PsycINFO databases following PRISMA guidelines. Two reviewers independently assessed study eligibility and determined the quality of the identified studies. Three reviewers independently executed data extraction by using a pre-piloted, standardized extraction form. The resulting indicators were grouped by topical similarity, creating a concise summary of the findings. Results The systematic search of all databases yielded a total of 7,360 references, of which sixteen were eligible for inclusion. The sixteen papers yielded a total of 48 unique indicators. Overall, a more pronounced depression severity, a younger age of onset, a history of prior poor treatment response, psychiatric comorbidity, somatic comorbidity, childhood trauma,psychosocial impairment, older age, and a socioeconomically disadvantaged status were found to be associated with proxies of need for highly specialized MDD care. Conclusions Several indicators ar

    Nonequilibrium stabilization of charge states in double quantum dots

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    We analyze the decoherence of charge states in double quantum dots due to cotunneling. The system is treated using the Bloch-Redfield generalized master equation for the Schrieffer-Wolff transformed Hamiltonian. We show that the decoherence, characterized through a relaxation τr\tau_{r} and a dephasing time τϕ\tau_{\phi}, can be controlled through the external voltage and that the optimum point, where these times are maximum, is not necessarily in equilibrium. We outline the mechanism of this nonequilibrium-induced enhancement of lifetime and coherence. We discuss the relevance of our results for recent charge qubit experiments.Comment: 5 pages, 5 figure

    Cost-utility of collaborative care for the treatment of comorbid major depressive disorder in outpatients with chronic physical conditions : A randomized controlled trial in the general hospital setting (CC-DIM)

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    The study was undertaken to establish if collaborative care (CC) is a cost-effective treatment model when provided in the general hospital outpatient setting, rather than the primary care setting, for patients with chronic physical conditions, such as diabetes mellitus (DM), chronic heart failure (CHF), and chronic obstructive pulmonary disease (COPD), with comorbid major depressive disorder (MDD). The researchers performed a randomized controlled trial (RCT) evaluating CC provided by a consultant psychiatric nurse (CPN) as care manager; a consultation–liaison (CL) psychiatrist for diagnosis, supervision, and the prescription of antidepressant medication; and a medical specialist who provided treatment for the chronic physical condition. They found CC to be cost-effective with an incremental cost-effectiveness ratio (ICER) of €24,690 per quality-adjusted life year (QALY). Due to the high disease burden in this patient group, this may indicate that the CC model and setting may be preferable. However, the study was small, so replication in a larger study is warranted

    Development and psychometric evaluation of the Decision Tool Anxiety Disorders, OCD and PTSD (DTAOP):Facilitating the early detection of patients in need of highly specialized care

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    Background: Early identification of patients with an anxiety disorder, obsessive-compulsive disorder (OCD), or post-traumatic stress disorder (PTSD) in need of highly specialized care could facilitate the selection of the optimal initial treatment in these patients. This paper describes the development and psychometric evaluation of the Decision Tool Anxiety Disorders, OCD and PTSD (DTAOP), which aims to aid clinicians in the early identification of patients with an anxiety disorder, OCD, or PTSD in need of highly specialized mental healthcare. Methods: A systematic literature review and a concept mapping procedure were carried out to inform the development of the DTAOP. To evaluate the psychometric properties of the DTAOP, a cross-sectional study in 454 patients with a DSM-IV-TR anxiety disorder was carried out. Feasibility was evaluated by the completion time and the content clarity of the DTAOP. Inter-rater reliability was assessed in a subsample of 87 patients. Spearman’s rank correlation coefficients between the DTAOP and EuroQol five-dimensional questionnaire (EQ-5D-5L) scores were computed to examine the convergent validity. Criterion validity was assessed against independent clinical judgments made by clinicians. Results: The average time required to complete the eight-item DTAOP was 4.6 min and the total DTAOP was evaluated as clear in the majority (93%) of the evaluations. Krippendorff’s alpha estimates ranged from 0.427 to 0.839. Based on the qualitative feedback, item wording and instructions were improved. As hypothesized, the DTAOP correlated negatively with EQ-5D-5L scores. The area under the curve was 0.826 and the cut-off score of >= 4 optimized sensitivity (70%) and specificity (71%). Conclusions: The DTAOP demonstrated excellent feasibility and good validity, but weak inter-rater reliability. Based on the qualitative feedback and reliability estimates, revisions and refinements of the wording and instructions were made, resulting in the final version of the DTAOP

    Gender differences in the implementation of school-based assessment in a Malaysian state

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    This study aims to identify the differences in assessment knowledge, school support, teacher readiness, teacher skills and challenges faced by male and female Grade 8 teachers who are involved in implementing School-Based Assessment (SBA) and the interrelationship among these five factors. In addition, this study explores the teachers’ views with regards to these five factors.This study uses a quantitative questionnaire designed by the researchers, and a total of 243 Grade 8 teachers answered the questionnaire.Qualitative data was then collected via semi-structured interviews which were conducted with 20 teachers. The findings show that male teachers are more ready to implement SBA compared to female teachers.Compared to the female teachers, the male teachers view school support as more important. In terms of knowledge, skills and challenges towards the implementation of SBA, there are no gender differences. The findings also show that there exist significant relationships among the five factors except between school support and challenges faced in SBA.Although male and female teachers share many similar views, the predominant view among female teachers when compared to the male teachers is that many challenges and issues need to be addressed in the implementation of SBA. The findings from the interviews also suggest that male teachers are more willing to accept changes when compared to the female teachers.This study has implications for the implementation of SBA in Malaysia because 63% of the teachers implementing SBA are females

    Adult reversal of cognitive phenotypes in neurodevelopmental disorders

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    Recent findings in mice suggest that it is possible to reverse certain neurodevelopmental disorders in adults. Changes in development, previously thought to be irreparable in adults, were believed to underlie the neurological and psychiatric phenotypes of a range of common mental health problems with a clear developmental component. As a consequence, most researchers have focused their efforts on understanding the molecular and cellular processes that alter development with the hope that early intervention could prevent the emergent pathology. Unexpectedly, several different animal model studies published recently, including animal models of autism, suggest that it may be possible to reverse neurodevelopmental disorders in adults: Addressing the underlying molecular and cellular deficits in adults could in several cases dramatically improve the neurocognitive phenotypes in these animal models. The findings reviewed here provide hope to millions of individuals afflicted with a wide range of neurodevelopmental disorders, including autism, since they suggest that it may be possible to treat or even cure them in adults
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