949 research outputs found

    Parallel structurally-symmetric sparse matrix-vector products on multi-core processors

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    We consider the problem of developing an efficient multi-threaded implementation of the matrix-vector multiplication algorithm for sparse matrices with structural symmetry. Matrices are stored using the compressed sparse row-column format (CSRC), designed for profiting from the symmetric non-zero pattern observed in global finite element matrices. Unlike classical compressed storage formats, performing the sparse matrix-vector product using the CSRC requires thread-safe access to the destination vector. To avoid race conditions, we have implemented two partitioning strategies. In the first one, each thread allocates an array for storing its contributions, which are later combined in an accumulation step. We analyze how to perform this accumulation in four different ways. The second strategy employs a coloring algorithm for grouping rows that can be concurrently processed by threads. Our results indicate that, although incurring an increase in the working set size, the former approach leads to the best performance improvements for most matrices.Comment: 17 pages, 17 figures, reviewed related work section, fixed typo

    Isolated Intraocular Relapse of Pediatric B-cell Precursor Acute Lymphoblastic Leukaemia Following Chimeric Antigen Receptor T-lymphocyte Therapy

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    Chimeric antigen receptor T-lymphocytes (CAR T) targeting the CD19 surface antigen have achieved a breakthrough in the treatment of multiply relapsed and refractory bone marrow (BM) disease in childhood B-cell precursor acute lymphoblastic leukaemia (B-ALL). The ability of CAR T therapy to treat extramedullary (EM) disease is less proven. However, early reports suggest trafficking of CART-cells to the central nervous system (CNS) as well as other EM sites. We describe a case of isolated intraocular relapse of pediatric B-ALL following CAR T-cell therapy, which had successfully controlled multiply relapsed BM and CNS disease. CAR T-cells may not be able to traffic into the eye, making it a "sanctuary" site during therapy

    Parallel solution of eigenproblems in structural dynamics using the implicitly restarted Lanczos method

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    This paper presents a parallel implementation of the implicitly restarted Lanczos method for the solution of large and sparse eigenproblems that occur in modal analysis of complex structures using the finite element method. The implicitly restarted technique improves convergence of the desired eigenvalues without the penalty of lost of orthogonality keeping the number of factorization steps in a modest size. In the parallel solution, a subdomain by subdomain approach was implemented and overlapping and non-overlapping mesh partitions were used. Compressed data structures in the formats CSRC and CSRC/CSR were employed to store the global matrices coefficients. The parallelization of numerical linear algebra operations presented in both Krylov and implicitly restarted methods are discussed

    Same old song and dance: An exploratory study of portrayal of physical activity in television programmes aimed at young adolescents

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    Abstract Objective Exposure to health-related behaviours on television has been shown to influence smoking and drinking in young people, but little research has been conducted on the portrayal physical activity. The aim of the current project was to explore the portrayal of physical activity in television programmes aimed specifically at adolescent females. Content analysis of 120 episodes of four popular adolescent television programmes was performed. Information on the type and context of physical activity, motivating factors and characters involved was recorded. Results Physical activity was portrayed 122 times, for a duration of 1 h and 31 min (3.2% of total viewing time). Physical activity was mainly portrayed as part of an informal activity as part of a group activity. Over half (53.2%) of scenes portrayed activity been carried out by teenagers. The types of activities portrayed were mostly of vigorous intensity (76.2%), for recreational purposes (78.7%) such as dancing (54.1%) and running (11.5%), and motivated by enjoyment. This study highlights that physical activity is portrayed infrequently, and often with a skewed representation of type of activity. There may be an opportunity to influence physical activity in young adolescents through the positioning of positive images of an active lifestyle in the media

    Older Adult Compendium of Physical Activities: Energy Costs of Human Activities in Adults Aged 60 and Older

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    Purpose: To describe the development of a Compendium for estimating the energy costs of activities in adults ≥60 years (OA Compendium). Methods: Physical activities (PAs) and their metabolic equivalent of task (MET) values were obtained from a systematic search of studies published in 4 sport and exercise databases (PubMed, Embase, SPORTDiscus (EBSCOhost), and Scopus) and a review of articles included in the 2011 Adult Compendium that measured PA in older adults. MET values were computed as the oxygen cost (VO2, mL/kg/min) during PA divided by 2.7 mL/kg/min (MET60+) to account for the lower resting metabolic rate in older adults. Results: We identified 68 articles and extracted energy expenditure data on 427 PAs. From these, we derived 99 unique Specific Activity codes with corresponding MET60+ values for older adults. We developed a website to present the OA Compendium MET60+ values: https://pacompendium.com. Conclusion: The OA Compendium uses data collected from adults ≥60 years for more accurate estimation of the energy cost of PAs in older adults. It is an accessible resource that will allow researchers, educators, and practitioners to find MET60+ values for older adults for use in PA research and practice

    Development and Validation of the Behavioral Tendencies Questionnaire

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    At a fundamental level, taxonomy of behavior and behavioral tendencies can be described in terms of approach, avoid, or equivocate (i.e., neither approach nor avoid). While there are numerous theories of personality, temperament, and character, few seem to take advantage of parsimonious taxonomy. The present study sought to implement this taxonomy by creating a questionnaire based on a categorization of behavioral temperaments/tendencies first identified in Buddhist accounts over fifteen hundred years ago. Items were developed using historical and contemporary texts of the behavioral temperaments, described as “Greedy/Faithful”, “Aversive/Discerning”, and “Deluded/Speculative”. To both maintain this categorical typology and benefit from the advantageous properties of forced-choice response format (e.g., reduction of response biases), binary pairwise preferences for items were modeled using Latent Class Analysis (LCA). One sample (n1 = 394) was used to estimate the item parameters, and the second sample (n2 = 504) was used to classify the participants using the established parameters and cross-validate the classification against multiple other measures. The cross-validated measure exhibited good nomothetic span (construct-consistent relationships with related measures) that seemed to corroborate the ideas present in the original Buddhist source documents. The final 13-block questionnaire created from the best performing items (the Behavioral Tendencies Questionnaire or BTQ) is a psychometrically valid questionnaire that is historically consistent, based in behavioral tendencies, and promises practical and clinical utility particularly in settings that teach and study meditation practices such as Mindfulness Based Stress Reduction (MBSR)

    Bilateral ureteropelvic disruption following blunt abdominal trauma: Case report

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    <p>Abstract</p> <p>Background</p> <p>Ureteral injury occurs in less than 1% of blunt abdominal trauma cases, partly because the ureters are relatively well protected in the retroperitoneum. Bilateral ureteral injury is extremely rare, with only 10 previously reported cases. Diagnosis may be delayed if ureteric injury is not suspected, and delay of 36 hours or longer has been observed in more than 50% of patients with ureteric injury following abdominal trauma, leading to increased morbidity.</p> <p>Case presentation</p> <p>A 29-year-old man was involved in a highway motor vehicle collision and was ejected from the front passenger seat even though wearing a seatbelt. He was in a preshock state at the scene of the accident. An intravenous line and left thoracic drain were inserted, and he was transported to our hospital by helicopter. Whole-body, contrast-enhanced computed tomography (CT) scan showed left diaphragmatic disruption, splenic injury, and a grade I injury to the left kidney with a retroperitoneal haematoma. He underwent emergency laparotomy. The left diaphragmatic and splenic injuries were repaired. Although a retroperitoneal haematoma was observed, his renal injury was treated conservatively because the haematoma was not expanding. In the intensive care unit, the patient's haemodynamic state was stable, but there was no urinary output for 9 hours after surgery. Anuresis prompted a review of the abdominal x-ray which had been performed after the contrast-enhanced CT. Leakage of contrast material from the ureteropelvic junctions was detected, and review of the repeat CT scan revealed contrast retention in the perirenal retroperitoneum bilaterally. He underwent cystoscopy and bilateral retrograde pyelography, which showed bilateral complete ureteral disruption, preventing placement of ureteral stents. Diagnostic laparotomy revealed complete disruption of the ureteropelvic junctions bilaterally. Double-J ureteral stents were placed bilaterally and ureteropelvic anastomoses were performed. The patient's postoperative progress was satisfactory and he was discharged on the 23<sup>rd </sup>day.</p> <p>Conclusion</p> <p>Diagnosis of ureteral injury was delayed, although delayed phase contrast-enhanced CT and abdominal x-rays performed after CT revealed the diagnosis early. Prompt detection and early repair prevented permanent renal damage and the necessity for nephrectomy.</p

    Validating MOSPA questionnaire for measuring physical activity in Pakistani women

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    BACKGROUND: Precise measurements of activity at a population level are important for monitoring trends and evaluating health promotion strategies. Few studies have assessed the measurement of physical activity in developing countries. The aim of this study was to validate the MOSPA (Monica Optional Study of Physical Activity) questionnaire which was developed for the WHO-Monitoring trends and determinants of cardiovasculr disease (MONICA) study sites. METHODS: The MOSPA questionnaire assesses energy expendtiture (EE) related to physical activity (employment, household work, transportation, and leisure time) over a one year period. This questionnaire has been described in the manuscript as the long term (LT) questionnaire. An adapted short term (ST) 5 day questionnaire was developed to assess convergent validity. Questionnaire data were compared with physical activity EE estimates from a Caltrac accelerometer and with body composition measures (height, weight and bioelectrical impedance) in 50 women from the Aga Khan University (AKU) hospital antenatal clinics, Pakistan. Other forms of EE i.e. resting EE and thermic effect of food were not assessd in this study. RESULTS: Subjects were aged 26 ± 3.8 years and were 16.1 ± 6.7 weeks pregnant. Their average weight was 58.8 ± 10.7 Kg. The average EE/day assessed by the Caltrac accelerometer, was 224 kcal and by MOSPA LT questionnaire it was 404 kcal. The questionnaires and Caltrac data were reasonably well correlated: r = 0.51 and r = 0.60 (P < 0.01) for LT and ST questionnaires respectively. Energy expenditure from questionnaire data was not correlated with body composition measures. CONCLUSION: The MOSPA questionnaire is useful in assessing physical activity levels in a sedentary population over a one year period

    Reported frequency of physical activity in a large epidemiological study: relationship to specific activities and repeatability over time

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    <p>Abstract</p> <p>Background</p> <p>How overall physical activity relates to specific activities and how reported activity changes over time may influence interpretation of observed associations between physical activity and health. We examine the relationships between various physical activities self-reported at different times in a large cohort study of middle-aged UK women.</p> <p>Methods</p> <p>At recruitment, Million Women Study participants completed a baseline questionnaire including questions on frequency of strenuous and of any physical activity. About 3 years later 589,896 women also completed a follow-up questionnaire reporting the hours they spent on a range of specific activities. Time spent on each activity was used to estimate the associated excess metabolic equivalent hours (MET-hours) and this value was compared across categories of physical activity reported at recruitment. Additionally, 18,655 women completed the baseline questionnaire twice, at intervals of up to 4 years; repeatability over time was assessed using the weighted kappa coefficient (κ<sub>weighted</sub>) and absolute percentage agreement.</p> <p>Results</p> <p>The average number of hours per week women reported doing specific activities was 14.0 for housework, 4.5 for walking, 3.0 for gardening, 0.2 for cycling, and 1.4 for all strenuous activity. Time spent and the estimated excess MET-hours associated with each activity increased with increasing frequency of any or strenuous physical activity reported at baseline (tests for trend, P < 0.003), although the associations for housework were by far the weakest (Spearman correlations, 0.01 and -0.03 respectively for housework, and 0.11-0.37 for all other activities). Repeatability of responses to physical activity questions on the baseline questionnaire declined significantly over time. For strenuous activity, absolute agreement was 64% (κ<sub>weighted </sub>= 0.71) for questionnaires administered less than 6 months apart, and 52% (κ<sub>weighted </sub>= 0.51) for questionnaires more than 2 years apart. Corresponding values for any physical activity were 57% (κ<sub>weighted </sub>= 0.67) and 47% (κ<sub>weighted </sub>= 0.58).</p> <p>Conclusions</p> <p>In this cohort, responses to simple questions on the frequency of any physical activity and of strenuous activity asked at baseline were associated with hours spent on specific activities and the associated estimated excess MET-hours expended, reported 3 years later. The weakest associations were with housework. Agreement for identical questions asked on two occasions about the frequency of physical activity decreased over time.</p
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