Surrogate Accelerated Bayesian Inversion for the Determination of the Thermal Diffusivity of a Material

Determination of the thermal properties of a material is an important task in many scientific and engineering applications. How a material behaves when subjected to high or fluctuating temperatures can be critical to the safety and longevity of a system's essential components. The laser flash experiment is a well-established technique for indirectly measuring the thermal diffusivity, and hence the thermal conductivity, of a material. In previous works, optimization schemes have been used to find estimates of the thermal conductivity and other quantities of interest which best fit a given model to experimental data. Adopting a Bayesian approach allows for prior beliefs about uncertain model inputs to be conditioned on experimental data to determine a posterior distribution, but probing this distribution using sampling techniques such as Markov chain Monte Carlo methods can be incredibly computationally intensive. This difficulty is especially true for forward models consisting of time-dependent partial differential equations. We pose the problem of determining the thermal conductivity of a material via the laser flash experiment as a Bayesian inverse problem in which the laser intensity is also treated as uncertain. We introduce a parametric surrogate model that takes the form of a stochastic Galerkin finite element approximation, also known as a generalized polynomial chaos expansion, and show how it can be used to sample efficiently from the approximate posterior distribution. This approach gives access not only to the sought-after estimate of the thermal conductivity but also important information about its relationship to the laser intensity, and information for uncertainty quantification. We also investigate the effects of the spatial profile of the laser on the estimated posterior distribution for the thermal conductivity

Recent developments in the treatment of anxiety disorders in children and adolescents

Anxiety disorders are among the most common emotional difficulties experienced by children and young people. They cause significant disturbance to the lives of young people and their families and present a risk for lifelong psychological disturbance. Effective psychological (ie, cognitive–behaviour therapy (CBT)) and pharmacological interventions (eg, selective serotonin reuptake inhibitors (SSRIs)) have been established. However, the risk of adverse effects and unknown long-term effects of using SSRIs has led to recommendations that CBT is delivered as a first-line intervention. Recent innovations have included the development of low-intensity CBT programmes, delivered briefly via parents or online. These hold promise to increase access to psychological therapies for children and young people with these common and severe difficulties

Do clinically anxious children cluster according to their expression of factors that maintain child anxiety?

Background Cognitive Behaviour Therapy (CBT) is an effective treatment for childhood anxiety disorders, yet a significant proportion of children do not benefit from it. CBT for child anxiety disorders typically includes a range of strategies that may not all be applicable for all affected children. This study explored whether there are distinct subgroups of children with anxiety disorders who are characterized by their responses to measures of the key mechanisms that are targeted in CBT (i.e. interpretation bias, perceived control, avoidance, physiological arousal, and social communication). Methods 379 clinically anxious children (7–12 years) provided indices of threat interpretation, perceived control, expected negative emotions and avoidance and measures of heart rate recovery following a speech task. Parents also reported on their children's social communication difficulties using the Social Communication Questionnaire (SCQ). Results Latent profile analysis identified three groups, reflecting (i) ‘Typically anxious’ (the majority of the sample and more likely to have Generalized anxiety disorder); (ii) ‘social difficulties’ (characterized by high SCQ and more likely to have social anxiety disorder and be male); (iii) ‘Avoidant’ (characterized by low threat interpretation but high avoidance and low perceived control). Limitations Some measures may have been influenced by confounding variables (e.g. physical variability in heart rate recovery). Sample characteristics of the group may limit the generalizability of the results. Conclusions Clinically anxious children appear to fall in to subgroups that might benefit from more targeted treatments that focus on specific maintenance factors. Treatment studies are now required to establish whether this approach would lead to more effective and efficient treatments

Child/Adolescent Anxiety Multimodal Study (CAMS): rationale, design, and methods

<p>Abstract</p> <p>Objective</p> <p>To present the design, methods, and rationale of the Child/Adolescent Anxiety Multimodal Study (CAMS), a recently completed federally-funded, multi-site, randomized placebo-controlled trial that examined the relative efficacy of cognitive-behavior therapy (CBT), sertraline (SRT), and their combination (COMB) against pill placebo (PBO) for the treatment of separation anxiety disorder (SAD), generalized anxiety disorder (GAD) and social phobia (SoP) in children and adolescents.</p> <p>Methods</p> <p>Following a brief review of the acute outcomes of the CAMS trial, as well as the psychosocial and pharmacologic treatment literature for pediatric anxiety disorders, the design and methods of the CAMS trial are described.</p> <p>Results</p> <p>CAMS was a six-year, six-site, randomized controlled trial. Four hundred eighty-eight (N = 488) children and adolescents (ages 7-17 years) with DSM-IV-TR diagnoses of SAD, GAD, or SoP were randomly assigned to one of four treatment conditions: CBT, SRT, COMB, or PBO. Assessments of anxiety symptoms, safety, and functional outcomes, as well as putative mediators and moderators of treatment response were completed in a multi-measure, multi-informant fashion. Manual-based therapies, trained clinicians and independent evaluators were used to ensure treatment and assessment fidelity. A multi-layered administrative structure with representation from all sites facilitated cross-site coordination of the entire trial, study protocols and quality assurance.</p> <p>Conclusions</p> <p>CAMS offers a model for clinical trials methods applicable to psychosocial and psychopharmacological comparative treatment trials by using state-of-the-art methods and rigorous cross-site quality controls. CAMS also provided a large-scale examination of the relative and combined efficacy and safety of the best evidenced-based psychosocial (CBT) and pharmacologic (SSRI) treatments to date for the most commonly occurring pediatric anxiety disorders. Primary and secondary results of CAMS will hold important implications for informing practice-relevant decisions regarding the initial treatment of youth with anxiety disorders.</p> <p>Trial registration</p> <p>ClinicalTrials.gov NCT00052078.</p

Somatic Complaints in Anxious Youth

This study examined (a) demographic and clinical characteristics associated with physical symptoms in anxiety-disordered youth and (b) the impact of cognitive-behavioral therapy (Coping Cat), medication (sertraline), their combination, and pill placebo on physical symptoms. Youth (N = 488, ages 7-17 years) with a principal diagnosis of generalized anxiety disorder, separation anxiety disorder, or social phobia participated as part of a multi-site, randomized controlled trial and received treatment delivered over 12 weeks. Diagnostic status, symptom severity, and impairment were assessed at baseline and week 12. The total number and severity of physical symptoms was associated with age, principal diagnosis, anxiety severity, impairment, and the presence of comorbid internalizing disorders. Common somatic complaints were headaches, stomachaches, head cold or sniffles, sleeplessness, and feeling drowsy or too sleepy. Physical symptoms decreased over the course of treatment, and were unrelated to treatment condition. Clinical implications and directions for future research are discussed (ClinicalTrials.gov number, NCT00052078)