558 research outputs found

    Large values of eigenfunctions on arithmetic hyperbolic 3-manifolds

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    Sub-Weyl subconvexity for Dirichlet L-functions to prime power moduli

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    Executable specifications for Java programs

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    Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2010.Cataloged from PDF version of thesis.Includes bibliographical references (p. 55-57).In this thesis, we present a unified environment for running declarative specifications in the context of an imperative object-oriented programming language. Specifications are Alloy-like, written in first-order relational logic with transitive closure, and the imperative language for this purpose is Java. By being able to mix imperative code with executable declarative specifications, the user can easily express constraint problems in-place, i.e. in terms of the existing data structures and objects on the heap. After a solution is found, our framework will automatically update the heap to reflect the solution, so the user can continue to manipulate the program heap in the usual imperative way, without ever having to manually translate the problem back and forth between the host programming environment and the solver language. We show that this approach is not only convenient, but, for certain problems, like puzzles or NP-complete graph algorithms, it can also outperform the manual implementation. We also present an optimization technique that allowed us to run our tool on heaps with almost 2000 objects.by Aleksandar Milicevic.S.M

    Confirmatory Factor Analysis of the Nepean Dysphoria Scale in a Clinical Sample

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    © 2018, Springer Science+Business Media, LLC, part of Springer Nature. The construct of dysphoria has been described inconsistently across a broad range of psychopathology. The term has been used to refer to an irritable state of discontent, but is also thought to incorporate anger, resentment and nonspecific symptoms associated with anxiety and depression, such as tension and unhappiness. The Nepean Dysphoria Scale has been developed to allow assessment of dysphoria, but its factor structure has not yet been investigated in clinical samples. We aimed to determine the latent structure of dysphoria as reflected by the Nepean Dysphoria Scale, using a clinical sample. Adults (N = 206) seeking treatment at a range of mental health services were administered the Nepean Dysphoria Scale. Four putative factor structures were investigated using confirmatory factor analysis: a single-factor model, a hierarchical model, a bifactor model and a four-factor model as identified in previous studies. No model fit the data except for a four-factor model when a revised 22-item version of the original 24-item scale was investigated. A four-factor structure similar to that identified in non-clinical samples was supported, albeit following the removal of two items. The Nepean Dysphoria Scale appears to have utility for the assessment of dysphoria in routine clinical settings

    Does emotional reasoning change during cognitive behavioural therapy for anxiety?

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    © 2015 Swedish Association for Behaviour Therapy. Abstract: Emotional reasoning refers to the use of subjective emotions, rather than objective evidence, to form conclusions about oneself and the world. It is a key interpretative bias in cognitive models of anxiety disorders and appears to be especially evident in individuals with anxiety disorders. However, the amenability of emotional reasoning to change during treatment has not yet been investigated. We sought to determine whether emotional reasoning tendencies change during a course of routine cognitive-behavioural therapy (CBT). Emotional reasoning tendencies were assessed in 36 individuals with a primary anxiety disorder who were seeking treatment at an outpatient clinic. Changes in anxiety and depressive symptoms as well as emotional reasoning tendencies after 12 sessions of CBT were examined in 25 individuals for whom there was complete data. Emotional reasoning tendencies were evident at pretreatment assessment. Although anxiety and depressive symptoms decreased during CBT, only one of six emotional reasoning interpretative styles (pertaining to conclusions that one is incompetent) changed significantly during the course of therapy. Attrition rates were high and there was not enough information regarding the extent to which therapy specifically focused on addressing emotional reasoning tendencies. Individuals seeking treatment for anxiety disorders appear to engage in emotional reasoning, however routine individual CBT does not appear to result in changes in emotional reasoning tendencies

    The structure and intensity of self-reported autonomic arousal symptoms across anxiety disorders and obsessive-compulsive disorder

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    © 2016 Elsevier B.V. All rights reserved. Background Heightened autonomic arousal symptoms (AAS) are assumed to be a central feature of anxiety disorders. However, it is unclear whether the magnitude and profile of AAS vary across anxiety disorders and whether heightened AAS characterises obsessive-compulsive disorder (OCD). Aims We sought to determine whether the intensity and structure of AAS varied across anxiety disorders and OCD. Method A sample of 459 individuals with a primary anxiety disorder or OCD were administered the Symptom Checklist-90R. Nine items referring to prototypic AAS were included in a latent class analysis. Results A 2-class solution (high and low AAS classes) best fitted the data. Participants comprising the high AAS class scored uniformly high across all assessed AAS symptoms. Older age and the presence of panic disorder, social anxiety disorder and generalized anxiety disorder predicted membership in the high AAS class. No OCD symptom dimension was significantly associated with membership in the high AAS class. Limitation AAS were assessed using a self-report measure and replication is needed using other methodologies. Conclusions These findings suggest that OCD may be sufficiently distinct from anxiety disorders and do not support subtyping of anxiety disorders on the basis of the predominant type of AAS. Therapeutic approaches that target AAS might best be applied in the treatment of panic disorder, social anxiety disorder and generalized anxiety disorder

    Dual resonance mechanisms facilitating enhanced optical transmission in coaxial waveguide arrays

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    We experimentally and computationally demonstrate high transmission through arrays of coaxial apertures with different geometries and arrangements in silver films. By studying both periodic and random arrangements of apertures, we were able to isolate transmission enhancement phenomena owing to surface plasmon effects from those owing to the excitation of cylindrical surface plasmons within the apertures themselves.This work was partially supported by the Office of Naval Research. The support of the Australian Research Council through its Centers of Excellence, Federation Fellow, and Discovery Programs is acknowledged

    Implementing QVT-R bidirectional model transformations using alloy

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    QVT Relations (QVT-R) is the standard language proposed by the OMG to specify bidirectional model transformations. Unfortunately, in part due to ambiguities and omissions in the original semantics, acceptance and development of effective tool support has been slow. Recently, the checking semantics of QVT-R has been clarified and formalized. In this paper we propose a QVT-R tool that complies to such semantics. Unlike any other existing tool, it also supports meta-models enriched with OCL constraints (thus avoiding returning ill-formed models), and proposes an alternative enforcement semantics that works according to the simple and predictable “principle of least change”. The implementation is based on an embedding of both QVT-R transformations and UML class diagrams (annotated with OCL) in Alloy, a lightweight formal specification language with support for automatic model finding via SAT solving.Fundação para a Ciência e a Tecnologi

    Synthesis, radiolabelling and in vitro and in vivo evaluation of a novel fluorinated ABP688 derivative for the PET imaging of metabotropic glutamate receptor subtype 5

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    (E)-3-(Pyridin-2-ylethynyl)cyclohex-2-enone O-(2-(3-18F-fluoropropoxy)ethyl) oxime ([18F]-PSS223) was evaluated in vitro and in vivo to establish its potential as a PET tracer for imaging metabotropic glutamate receptor subtype 5 (mGluR5). [18F]-PSS223 was obtained in 20% decay corrected radiochemical yield whereas the non-radioactive PSS223 was accomplished in 70% chemical yield in a SN2 reaction of common intermediate mesylate 8 with potassium fluoride. The in vitro binding affinity of [18F]-PSS223 was measured directly in a Scatchard assay to give Kd = 3.34 ± 2.05 nM. [18F]-PSS223 was stable in PBS and rat plasma but was significantly metabolized by rat liver microsomal enzymes, but to a lesser extent by human liver microsomes. Within 60 min, 90% and 20% of [18F]-PSS223 was metabolized by rat and human microsome enzymes, respectively. In vitro autoradiography on horizontal rat brain slices showed heterogeneous distribution of [18F]-PSS223 with the highest accumulation in brain regions where mGluR5 is highly expressed (hippocampus, striatum and cortex). Autoradiography in vitro under blockade conditions with ABP688 confirmed the high specificity of [18F]-PSS223 for mGluR5. Under the same blocking conditions but using the mGluR1 antagonist, JNJ16259685, no blockade was observed demonstrating the selectivity of [18F]-PSS223 for mGluR5 over mGluR1. Despite favourable in vitro properties of [18F]-PSS223, a clear-cut visualization of mGluR5- rich brain regions in vivo in rats was not possible mainly due to a fast clearance from the brain and low metabolic stability of [18F]-PSS223

    Synaptic Loss in Primary Tauopathies Revealed by [11 C]UCB-J Positron Emission Tomography.

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    BACKGROUND: Synaptic loss is a prominent and early feature of many neurodegenerative diseases. OBJECTIVES: We tested the hypothesis that synaptic density is reduced in the primary tauopathies of progressive supranuclear palsy (PSP) (Richardson's syndrome) and amyloid-negative corticobasal syndrome (CBS). METHODS: Forty-four participants (15 CBS, 14 PSP, and 15 age-/sex-/education-matched controls) underwent PET with the radioligand [11 C]UCB-J, which binds to synaptic vesicle glycoprotein 2A, a marker of synaptic density; participants also had 3 Tesla MRI and clinical and neuropsychological assessment. RESULTS: Nine CBS patients had negative amyloid biomarkers determined by [11 C]PiB PET and hence were deemed likely to have corticobasal degeneration (CBD). Patients with PSP-Richardson's syndrome and amyloid-negative CBS were impaired in executive, memory, and visuospatial tasks. [11 C]UCB-J binding was reduced across frontal, temporal, parietal, and occipital lobes, cingulate, hippocampus, insula, amygdala, and subcortical structures in both PSP and CBD patients compared to controls (P < 0.01), with median reductions up to 50%, consistent with postmortem data. Reductions of 20% to 30% were widespread even in areas of the brain with minimal atrophy. There was a negative correlation between global [11 C]UCB-J binding and the PSP and CBD rating scales (R = -0.61, P < 0.002; R = -0.72, P < 0.001, respectively) and a positive correlation with the revised Addenbrooke's Cognitive Examination (R = 0.52; P = 0.01). CONCLUSIONS: We confirm severe synaptic loss in PSP and CBD in proportion to disease severity, providing critical insight into the pathophysiology of primary degenerative tauopathies. [11 C]UCB-J may facilitate treatment strategies for disease-modification, synaptic maintenance, or restoration. © 2020 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society
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