Implementing Multidisciplinary and Multi-Zonal Applications Using MPI

Multidisciplinary and multi-zonal applications are an important class of applications in the area of Computational Aerosciences. In these codes, two or more distinct parallel programs or copies of a single program are utilized to model a single problem. To support such applications, it is common to use a programming model where a program is divided into several single program multiple data stream (SPMD) applications, each of which solves the equations for a single physical discipline or grid zone. These SPMD applications are then bound together to form a single multidisciplinary or multi-zonal program in which the constituent parts communicate via point-to-point message passing routines. Unfortunately, simple message passing models, like Intel's NX library, only allow point-to-point and global communication within a single system-defined partition. This makes implementation of these applications quite difficult, if not impossible. In this report it is shown that the new Message Passing Interface (MPI) standard is a viable portable library for implementing the message passing portion of multidisciplinary applications. Further, with the extension of a portable loader, fully portable multidisciplinary application programs can be developed. Finally, the performance of MPI is compared to that of some native message passing libraries. This comparison shows that MPI can be implemented to deliver performance commensurate with native message libraries

Fractionating impulsivity: commentary on "choice impulsivity" and "rapid-response impulsivity" articles by Hamilton and colleagues.

Comments on the original articles "Rapid-response impulsivity: Definitions, measurement issues, and clinical implications" (see record 2015-14753-004) and "Choice impulsivity: Definitions, measurement issues, and clinical implications" (see record 2015-14753-005) by Hamilton, Mitchell, et al. and Hamilton, Littlefield, et al., respectively. The present authors note that research has made important steps toward understanding impulsivity. Rapid-Response Impulsivity and Choice Impulsivity appear to be dissociable in terms of underlying neural circuitry and associated neurochemical modulation. Although various cognitive paradigms have been developed that tap these two functions, as Hamilton and colleagues correctly argue, there is a need for standardized measurements to be validated and agreed on, and for academics and clinicians to work together in order to tackle several pressing and related questions.This is the author accepted manuscript. The final version is available from the American Psychological Association via http://dx.doi.org/10.1037/per000012

Experimental Evaluation of SIMD PE-Mask Generation and Hybrid Mode Parallel Computing on Multi- Microprocessor Systems

Experimentation aimed at determining the potential efficiency of multi-microprocessor designs of SIMD machines is reported. The experimentation is based on timing measurements made on the PASM system prototype at Purdue. The application used to measure and evaluate this phenomenon was bitonic sorting, which has feasible solutions in both SIMD and MIMD modes of computation, as well as in at least two hybrids of SlMD and MIMD modes. Bitonic sorting was coded in these four ways and experiments were performed that examine the tradeoffs among all of these modes. Also, a new PE mask generation scheme for multiple of-the-shelf microprocessor based SIMD systems is proposed, and its performance was measured

Altered cognitive response to serotonin challenge as a candidate endophenotype for obsessive-compulsive disorder.

RATIONALE: Obsessive-compulsive disorder (OCD) implicates dysfunction of orbitofrontal and insula-related circuitry and of the serotonin system. There is an on-going search in psychiatry for intermediate biological markers, termed 'endophenotypes', that exist not only in patients with a given disorder but also in their clinically unaffected first-degree relatives. OBJECTIVE: Pharmacological challenge is recognized as a means of eliciting an endophenotype, but this strategy has yet to be used in OCD. METHODS: Twenty-three OCD patients without comorbidities (12 [52.2 %] female), 13 clinically asymptomatic first-degree relatives of OCD patients (11 [84.6 %] female) and 27 healthy controls (16 [59.3 %] female) received single-dose escitalopram (20 mg) and placebo in a randomized double-blind crossover design. Effects of treatment on decision-making were quantified using the Cambridge Gamble Task (CGT) in conjunction with a mixed model analysis of covariance (ANCOVA). RESULTS: There was a significant interaction between serotonergic challenge and group for risk adjustment on the CGT (F = 4.1406; p = 0.02). Only controls showed a significant placebo-drug change in risk adjustment (p = 0.02; versus p > 0.10). Numerically, escitalopram was associated with increase in risk adjustment in controls and reductions in the other groups. Change in risk adjustment was similar in OCD patients and relatives (p = 0.806) and differed significantly from controls (p = 0.007; p = 0.041, respectively). CONCLUSIONS: Individuals with OCD, and first-degree relatives, showed an altered cognitive response to serotonin challenge. This is the first demonstration of a candidate pharmacological challenge endophenotype for the disorder. Future work should confirm these findings in a larger sample size and ideally extend them to other cognitive paradigms, utilizing functional neuroimaging.This work was supported by the Medical Research Council of South Africa, the Obsessive-Compulsive Foundation (Prof Stein), the National Research Foundation of South Africa (Prof Lochner), an unrestricted grant from Lundbeck H/S and by a Starter Grant for Clinical Lecturers from the Academy of Medical Sciences UK (Dr Chamberlain).This is the author accepted manuscript. The final version is available from Springer via http://dx.doi.org/10.1007/s00213-015-4172-

Differential effects of sertraline and cognitive behavioural therapy on behavioural inhibition in patients with obsessive compulsive disorder

© 2024 The Author(s). Published by Wolters Kluwer Health, Inc. This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY), https://creativecommons.org/licenses/by/4.0/Patients with obsessive compulsive disorder (OCD) randomised to sertraline, manualised cognitive behavioural therapy (CBT), or combination (sertraline + CBT), underwent cognitive assessment. Cognitive testing was conducted at baseline and at week 16. The stop signal reaction time task (SSRT) was used to evaluate motor impulsivity and attentional flexibility was evaluated using the intra/extra-dimensional set shifting task. Paired-samples t-tests or nonparametric variants were used to compare baseline and posttreatment scores within each treatment group. Forty-five patients were tested at baseline (sertraline n = 14; CBT n = 14; sertraline + CBT n = 17) and 23 patients at week 16 (sertraline n = 6; CBT n = 7; sertraline + CBT n = 10). The mean dosage of sertraline was numerically higher in those taking sertraline as a monotherapy (166.67 mg) compared with those taking sertraline in combination with CBT (100 mg). Analysis of pre-post treatment scores using an intent-to-treat-analysis found a significant reduction in the SSRT in those treated with sertraline, whilst there was no significant change on this task for those treated with CBT or the combination. This study found that motor inhibition improved significantly following sertraline monotherapy. Suboptimal sertraline dosing might explain the failure to detect an effect on motor inhibition in the group receiving combination of sertraline + CBT. Higher dose sertraline may have broader cognitive effects than CBT for OCD, motor impulsivity may have value as a measure of treatment outcome and, by extension, the SSRT could serve as a biomarker for personalising care.Peer reviewe

Mapping Compulsivity in the DSM-5 Obsessive Compulsive and Related Disorders: Cognitive Domains, Neural Circuitry, and Treatment.

Compulsions are repetitive, stereotyped thoughts and behaviors designed to reduce harm. Growing evidence suggests that the neurocognitive mechanisms mediating behavioral inhibition (motor inhibition, cognitive inflexibility) reversal learning and habit formation (shift from goal-directed to habitual responding) contribute toward compulsive activity in a broad range of disorders. In obsessive compulsive disorder, distributed network perturbation appears focused around the prefrontal cortex, caudate, putamen, and associated neuro-circuitry. Obsessive compulsive disorder-related attentional set-shifting deficits correlated with reduced resting state functional connectivity between the dorsal caudate and the ventrolateral prefrontal cortex on neuroimaging. In contrast, experimental provocation of obsessive compulsive disorder symptoms reduced neural activation in brain regions implicated in goal-directed behavioral control (ventromedial prefrontal cortex, caudate) with concordant increased activation in regions implicated in habit learning (presupplementary motor area, putamen). The ventromedial prefrontal cortex plays a multifaceted role, integrating affective evaluative processes, flexible behavior, and fear learning. Findings from a neuroimaging study of Pavlovian fear reversal, in which obsessive compulsive disorder patients failed to flexibly update fear responses despite normal initial fear conditioning, suggest there is an absence of ventromedial prefrontal cortex safety signaling in obsessive compulsive disorder, which potentially undermines explicit contingency knowledge and may help to explain the link between cognitive inflexibility, fear, and anxiety processing in compulsive disorders such as obsessive compulsive disorder

Problematic use of the internet during the COVID-19 pandemic: Good practices and mental health recommendations.

With the onset of the COVID-19 pandemic and the accelerated spread of the SARS-CoV-2 virus came jurisdictional limitations on mobility of citizens and distinct alterations in their daily routines. Confined to their homes, many people increased their overall internet use, with problematic use of the internet (PUI) becoming a potential reason for increased mental health concerns. Our narrative review summarizes information on the extent of PUI during the pandemic, by focusing on three types: online gaming, gambling and pornography viewing. We conclude by providing guidance for mental health professionals and those affected by PUI (with an outline of immediate research priorities and best therapeutic approaches), as well as for the general public (with an overview of safe and preventative practices)

The profile of executive function in OCD hoarders and hoarding disorder

Hoarding disorder is a new mental disorder in DSM-5. It is classified alongside OCD and other presumably related disorders in the Obsessive-Compulsive and Related Disorders chapter. We examined cognitive performance in two distinct groups comprising individuals with both OCD and severe hoarding, and individuals with hoarding disorder without comorbid OCD. Participants completed executive function tasks assessing inhibitory control, cognitive flexibility, spatial planning, probabilistic learning and reversal and decision making. Compared to a matched healthy control group, OCD hoarders showed significantly worse performance on measures of response inhibition, set shifting, spatial planning, probabilistic learning and reversal, with intact decision making. Despite having a strikingly different clinical presentation, individuals with only hoarding disorder did not differ significantly from OCD hoarders on any cognitive measure suggesting the two hoarding groups have a similar pattern of cognitive difficulties. Tests of cognitive flexibility were least similar across the groups, but differences were small and potentially reflected subtle variation in underlying brain pathology together with psychometric limitations. These results highlight both commonalities and potential differences between OCD and hoarding disorder, and together with other lines of evidence, support the inclusion of the new disorder within the new Obsessive-Compulsive and Related Disorders chapter in DSM-5

Analytical validation of a standardised scoring protocol for Ki67 immunohistochemistry on breast cancer excision whole sections: an international multicentre collaboration

Aims The nuclear proliferation marker Ki67 assayed by immunohistochemistry has multiple potential uses in breast cancer, but an unacceptable level of interlaboratory variability has hampered its clinical utility. The International Ki67 in Breast Cancer Working Group has undertaken a systematic programme to determine whether Ki67 measurement can be analytically validated and standardised among laboratories. This study addresses whether acceptable scoring reproducibility can be achieved on excision whole sections. Methods and results Adjacent sections from 30 primary ER+ breast cancers were centrally stained for Ki67 and sections were circulated among 23 pathologists in 12 countries. All pathologists scored Ki67 by two methods: (i) global: four fields of 100 tumour cells each were selected to reflect observed heterogeneity in nuclear staining; (ii) hot-spot: the field with highest apparent Ki67 index was selected and up to 500 cells scored. The intraclass correlation coefficient (ICC) for the global method [confidence interval (CI) = 0.87; 95% CI = 0.799-0.93] marginally met the prespecified success criterion (lower 95% CI >= 0.8), while the ICC for the hot-spot method (0.83; 95% CI = 0.74-0.90) did not. Visually, interobserver concordance in location of selected hot-spots varies between cases. The median times for scoring were 9 and 6 min for global and hot-spot methods, respectively. Conclusions The global scoring method demonstrates adequate reproducibility to warrant next steps towards evaluation for technical and clinical validity in appropriate cohorts of cases. The time taken for scoring by either method is practical using counting software we are making publicly available. Establishment of external quality assessment schemes is likely to improve the reproducibility between laboratories further

Analytical validation of a standardized scoring protocol for Ki67: phase 3 of an international multicenter collaboration

Pathological analysis of the nuclear proliferation biomarker Ki67 has multiple potential roles in breast and other cancers. However, clinical utility of the immunohistochemical (IHC) assay for Ki67 immunohistochemistry has been hampered by unacceptable between-laboratory analytical variability. The International Ki67 Working Group has conducted a series of studies aiming to decrease this variability and improve the evaluation of Ki67. This study tries to assess whether acceptable performance can be achieved on prestained core-cut biopsies using a standardized scoring method. Sections from 30 primary ER+ breast cancer core biopsies were centrally stained for Ki67 and circulated among 22 laboratories in 11 countries. Each laboratory scored Ki67 using three methods: (1) global (4 fields of 100 cells each); (2) weighted global (same as global but weighted by estimated percentages of total area); and (3) hot-spot (single field of 500 cells). The intraclass correlation coefficient (ICC), a measure of interlaboratory agreement, for the unweighted global method (0.87; 95% credible interval (CI): 0.81–0.93) met the prespecified success criterion for scoring reproducibility, whereas that for the weighted global (0.87; 95% CI: 0.7999–0.93) and hot-spot methods (0.84; 95% CI: 0.77–0.92) marginally failed to do so. The unweighted global assessment of Ki67 IHC analysis on core biopsies met the prespecified criterion of success for scoring reproducibility. A few cases still showed large scoring discrepancies. Establishment of external quality assessment schemes is likely to improve the agreement between laboratories further. Additional evaluations are needed to assess staining variability and clinical validity in appropriate cohorts of samples