31,206 research outputs found

    Toward specifying Pervasive Developmental Disorder - Not Otherwise Specified

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    Pervasive developmental disorder-not otherwise specified (PDD-NOS) is the most common and least satisfactory of the PDD diagnoses. It is not formally operationalized, which limits its reliability and has hampered attempts to assess its validity. We aimed, first, to improve the reliability and replicability of PDD-NOS by operationalizing its DSM-IV-TR description and, second, to test its validity through comparison with autistic disorder (AD) and Asperger's disorder (AsD). In a sample of 256 young people (mean age = 9.1 years) we used Developmental, Diagnostic and Dimensional (3Di) algorithmic analysis to classify DSM-IV-TR AD (n = 97), AsD (n = 93) and PDD-NOS (n = 66). Groups were compared on independent measures of core PDD symptomatology, associated autistic features, and intelligence. Contrary to the assumption that PDD-NOS is heterogeneous, almost all (97%) of those with PDD-NOS had one distinct symptom pattern, namely impairments in social reciprocity and communication, without significant repetitive and stereotyped behaviors (RSB). Compared to AD and AsD, they had comparably severe but more circumscribed social communication difficulties, with fewer non-social features of autism, such as sensory, feeding and visuo-spatial problems. These individuals appear to have a distinct variant of autism that does not merely sit at the less severe end of the same continuum of symptoms. The current draft guidelines for DSM-V, which mandate the presence of RSBs for any PDD diagnosis, would exclude such people from the autistic spectrum. Autism Res 2011, 4: 121-131. (C) 2011 International Society for Autism Research, Wiley Periodicals, Inc

    Incidence of mild cognitive impairment and dementia in Parkinson's disease: The Parkinson's disease cognitive impairment study

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    Background: Cognitive impairment in Parkinson's disease (PD) includes a spectrum varying from Mild Cognitive Impairment (PD-MCI) to PD Dementia (PDD). The main aim of the present study is to evaluate the incidence of PD-MCI, its rate of progression to dementia, and to identify demographic and clinical characteristics which predict cognitive impairment in PD patients. Methods: PD patients from a large hospital-based cohort who underwent at least two comprehensive neuropsychological evaluations were retrospectively enrolled in the study. PD-MCI and PDD were diagnosed according to the Movement Disorder Society criteria. Incidence rates of PD-MCI and PDD were estimated. Clinical and demographic factors predicting PD-MCI and dementia were evaluated using Cox proportional hazard model. Results: Out of 139 enrolled PD patients, 84 were classified with normal cognition (PD-NC), while 55 (39.6%) fulfilled the diagnosis of PD-MCI at baseline. At follow-up (mean follow-up 23.5 ¬Ī 10.3 months) 28 (33.3%) of the 84 PD-NC at baseline developed MCI and 4 (4.8%) converted to PDD. The incidence rate of PD-MCI was 184.0/1000 pyar (95% CI 124.7-262.3). At multivariate analysis a negative association between education and MCI development at follow-up was observed (HR 0.37, 95% CI 0.15-0.89; p = 0.03). The incidence rate of dementia was 24.3/1000 pyar (95% CI 7.7-58.5). Out of 55 PD-MCI patients at baseline, 14 (25.4%) converted to PDD, giving an incidence rate of 123.5/1000 pyar (95% CI 70.3-202.2). A five time increased risk of PDD was found in PD patients with MCI at baseline (RR 5.09, 95% CI 1.60-21.4). Conclusion: Our study supports the relevant role of PD-MCI in predicting PDD and underlines the importance of education in reducing the risk of cognitive impairment

    Applications and accuracy of the parallel diagonal dominant algorithm

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    The Parallel Diagonal Dominant (PDD) algorithm is a highly efficient, ideally scalable tridiagonal solver. In this paper, a detailed study of the PDD algorithm is given. First the PDD algorithm is introduced. Then the algorithm is extended to solve periodic tridiagonal systems. A variant, the reduced PDD algorithm, is also proposed. Accuracy analysis is provided for a class of tridiagonal systems, the symmetric, and anti-symmetric Toeplitz tridiagonal systems. Implementation results show that the analysis gives a good bound on the relative error, and the algorithm is a good candidate for the emerging massively parallel machines

    Use of Desulfovibrio and Escherichia coli Pd-nanocatalysts in reduction of Cr(VI) and hydrogenolytic dehalogenation of polychlorinated biphenyls and used transformer oil

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    BACKGROUND Desulfovibrio spp. biofabricate metallic nanoparticles (e.g. ‚ÄėBio-Pd‚Äô) which catalyse the reduction of Cr(VI) to Cr(III) and dehalogenate polychlorinated biphenyls (PCBs). Desulfovibrio spp. are anaerobic and produce H2S, a potent catalyst poison, whereas Escherichia coli can be pre-grown aerobically to high density, has well defined molecular tools, and also makes catalytically-active ‚ÄėBio-Pd‚Äô. The first aim was to compare ‚ÄėBio-Pd‚Äô catalysts made by Desulfovibrio spp. and E. coli using suspended and immobilised catalysts. The second aim was to evaluate the potential for Bio-Pd-mediated dehalogenation of PCBs in used transformer oils, which preclude recovery and re-use.\ud RESULTS Catalysis via Bio-PdD. desulfuricans and Bio-PdE. coli was compared at a mass loading of Pd:biomass of 1:3 via reduction of Cr(VI) in aqueous solution (immobilised catalyst) and hydrogenolytic release of Cl- from PCBs and used transformer oil (catalyst suspensions). In both cases Bio-PdD. desulfuricans outperformed Bio-Pd E. coli by ~3.5-fold, attributable to a ~3.5-fold difference in their Pd-nanoparticle surface areas determined by magnetic measurements (Bio-PdD. desulfuricans) and by chemisorption analysis (Bio-PdE. coli). Small Pd particles were confirmed on D. desulfuricans and fewer, larger ones on E. coli via electron microscopy. Bio-PdD. desulfuricans-mediated chloride release from used transformer oil (5.6 ¬Ī\pm 0.8 őľ\mug mL-1 ) was comparable to that observed using several PCB reference materials. \ud CONCLUSIONS At a loading of 1:3 Pd: biomass Bio-PdD. desulfuricans is 3.5-fold more active than Bio-PdE. coli, attributable to the relative catalyst surface areas reflected in the smaller nanoparticle sizes of the former. This study also shows the potential of Bio-PdD. desulfuricans to remediate used transformer oil

    Comparison of different strategies to measure medication adherence via claims data in patients with chronic heart failure

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    Medication adherence correlates with morbidity and mortality in patients with chronic heart failure (CHF), but is difficult to assess. We conducted a retrospective methodological cohort study in 3,808 CHF patients, calculating adherence as proportion of days covered (PDC) utilizing claims data from 2010 to 2015. We aimed to compare different parameters’ influence on the PDC of elderly CHF patients exemplifying a complex chronic disease. Investigated parameters were the assumed prescribed daily dose (PDD), stockpiling, and periods of hospital stay. Thereby, we investigated a new approach using the PDD assigned to different percentiles. The different dose assumptions had the biggest influence on the PDC, with variations from 41.9% to 83.7%. Stockpiling and hospital stays increased the values slightly. These results queries that a reliable PDC can be calculated with an assumed PDD. Hence, results based on an assumed PDD have to be interpreted carefully and should be presented with sensitivity analyses to show the PDC's possible range

    Onset of Mild Cognitive Impairment in Parkinson Disease

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    Objective: Characterize the onset and timing of cognitive decline in Parkinson disease (PD) from the first recognizable stage of cognitively symptomatic PD-mild cognitive impairment (PD-MCI) to PD dementia (PDD). Thirty-nine participants progressed from PD to PDD and 25 remained cognitively normal. Methods: Bayesian-estimated disease-state models described the onset of an individual’s cognitive decline across 12 subtests with a change point. Results: Subtests measuring working memory, visuospatial processing ability, and crystalized memory changed significantly 3 to 5 years before their first nonzero Clinical Dementia Rating and progressively worsened from PD to PD-MCI to PDD. Crystalized memory deficits were the hallmark feature of imminent conversion of cognitive status. Episodic memory tasks were not sensitive to onset of PD-MCI. For cognitively intact PD, all 12 subtests showed modest linear decline without evidence of a change point. Conclusions: Longitudinal disease-state models support a prodromal dementia stage (PD-MCI) marked by early declines in working memory and visuospatial processing beginning 5 years before clinical diagnosis of PDD. Cognitive declines in PD affect motor ability (bradykinesia), working memory, and processing speed (bradyphrenia) resulting in PD-MCI where visuospatial imagery and memory retrieval deficits manifest before eventual development of overt dementia. Tests of episodic memory may not be sufficient to detect and quantify cognitive decline in PD

    High-Dimensional Stochastic Design Optimization by Adaptive-Sparse Polynomial Dimensional Decomposition

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    This paper presents a novel adaptive-sparse polynomial dimensional decomposition (PDD) method for stochastic design optimization of complex systems. The method entails an adaptive-sparse PDD approximation of a high-dimensional stochastic response for statistical moment and reliability analyses; a novel integration of the adaptive-sparse PDD approximation and score functions for estimating the first-order design sensitivities of the statistical moments and failure probability; and standard gradient-based optimization algorithms. New analytical formulae are presented for the design sensitivities that are simultaneously determined along with the moments or the failure probability. Numerical results stemming from mathematical functions indicate that the new method provides more computationally efficient design solutions than the existing methods. Finally, stochastic shape optimization of a jet engine bracket with 79 variables was performed, demonstrating the power of the new method to tackle practical engineering problems.Comment: 18 pages, 2 figures, to appear in Sparse Grids and Applications--Stuttgart 2014, Lecture Notes in Computational Science and Engineering 109, edited by J. Garcke and D. Pfl\"{u}ger, Springer International Publishing, 201
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