795 research outputs found

    Dissociation of structural and functional integrities of the motor system in amyotrophic lateral sclerosis and behavioral-variant frontotemporal dementia

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    Background and Purpose: This study investigated the structural and functional changes in the motor system in amyotrophic lateral sclerosis (ALS; n=25) and behavioral-variant fronto-temporal dementia (bvFTD; n=17) relative to healthy controls (n=37). Methods: Structural changes were examined using a region-of-interest approach, applying voxel-based morphometry for gray-matter changes and diffusion tensor imaging for white-matter changes. Functional changes in the motor system were elucidated using threshold-tracking transcranial magnetic stimulation (TMS) measurements of upper motor-neuron excitability. Results: The structural analyses showed that in ALS there were more white-matter changes in the corticospinal and motor-cortex regions and more gray-matter changes in the cerebellum in comparison to controls. bvFTD showed substantial gray- and white-matter changes across virtually all motor-system regions compared to controls, although the brainstem was affected less than the other regions. Direct comparisons across patient groups showed that the gray- and white-matter motor-system changes inclusive of the motor cortex were greater in bvFTD than in ALS. By contrast, the functional integrity of the motor system was more adversely affected in ALS than in bvFTD, with both patient groups showing increased excitability of upper motor neurons compared to controls. Conclusions: Cross-correlation of structural and functional data further revealed a neural dissociation of different motor-system regions and tracts covarying with the TMS excitability across both patient groups. The structural and functional motor-system integrities appear to be dissociated between ALS and bvFTD, which represents useful information for the diagnosis of motor-system changes in these two disorders

    Idiopathic Hemochromotosis and Alpha‐1‐Antitrypsin Deficiency: Coexistence in a Family with Progressive Liver Disease in the Proband

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    A patient with coexistent hemochromatosis and alpha‐1‐antitrypsin deficiency which led to cirrhosis and death despite adequate therapy for hemochromatosis is reported. Evaluation of the family revealed first degree relatives with iron overload and others with alpha‐1‐antitrypsin deficiency but none with both conditions. The role of family studies in the early recognition and possible prevention of overt clinical disease in individuals with either of these two genetic diseases is discussed. Copyright © 1983 American Association for the Study of Liver Disease

    Genetic Variation at Nuclear Loci Fails to Distinguish Two Morphologically Distinct Species of Aquilegia

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    Aquilegia formosa and pubescens are two closely related species belonging to the columbine genus. Despite their morphological and ecological differences, previous studies have revealed a large degree of intercompatibility, as well as little sequence divergence between these two taxa [1], [2]. We compared the inter- and intraspecific patterns of variation for 9 nuclear loci, and found that the two species were practically indistinguishable at the level of DNA sequence polymorphism, indicating either very recent speciation or continued gene flow. As a comparison, we also analyzed variation at two loci across 30 other Aquilegia taxa; this revealed slightly more differentiation among taxa, which seemed best explained by geographic distance. By contrast, we found no evidence for isolation by distance on a more local geographic scale. We conclude that the extremely low levels of genetic differentiation between A. formosa and A.pubescens at neutral loci will facilitate future genome-wide scans for speciation genes

    Forecasting in dynamic factor models using Bayesian model averaging

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    This paper considers the problem of forecasting in dynamic factor models using Bayesian model averaging. Theoretical justifications for averaging across models, as opposed to selecting a single model, are given. Practical methods for implementing Bayesian model averaging with factor models are described. These methods involve algorithms which simulate from the space defined by all possible models. We discuss how these simulation algorithms can also be used to select the model with the highest marginal likelihood (or highest value of an information criterion) in an efficient manner. We apply these methods to the problem of forecasting GDP and inflation using quarterly U.S. data on 162 time series. For both GDP and inflation, we find that the models which contain factors do out-forecast an AR(p), but only by a relatively small amount and only at short horizons. We attribute these findings to the presence of structural instability and the fact that lags of dependent variable seem to contain most of the information relevant for forecasting. Relative to the small forecasting gains provided by including factors, the gains provided by using Bayesian model averaging over forecasting methods based on a single model are appreciable

    Greater diaphragm fatigability in individuals with recurrent low back pain.

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    The diaphragm plays an important role in spinal control. Increased respiratory demand compromises spinal control, especially in individuals with low back pain (LBP). The objective was to determine whether individuals with LBP exhibit greater diaphragm fatigability compared to healthy controls. Transdiaphragmatic twitch pressures (TwPdi) were recorded in 10 LBP patients and 10 controls, before and 20 and 45 min after inspiratory muscle loading (IML). Individuals with LBP showed a significantly decreased potentiated TwPdi, 20 min (-20%) (p=0.002) and 45 min (-17%) (p=0.006) after IML. No significant decline was observed in healthy individuals, 20 min (-9%) (p=0.662) and 45 min (-5%) (p=0.972) after IML. Diaphragm fatigue (TwPdi fall ≄ 10%) was present in 80% (20 min after IML) and 70% (45 min after IML) of the LBP patients compared to 40% (p=0.010) and 30% (p=0.005) of the controls, respectively. Individuals with LBP exhibit propensity for diaphragm fatigue, which was not observed in controls. An association with reduced spinal control warrants further study

    PrintSense: a versatile sensing technique to support multimodal flexible surface interaction

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    We present a multimodal on-surface and near-surface sensing technique for planar, curved and flexible surfaces. Our technique leverages temporal multiplexing of signals coming from a universal interdigitated electrode design, which is printed as a single conductive layer on a flexible substrate. It supports sensing of touch and proximity input, and moreover is capable of capturing several levels of pressure and flexing. We leverage recent developments in conductive inkjet printing as a way to prototype electrode patterns, and combine this with our hardware module for supporting the full range of sensing methods. As the technique is low-cost and easy to implement, it is particularly well-suited for prototyping touch- and hover-based user interfaces, including curved and deformable ones

    Effect of a consumer-focused website for low back pain on health literacy, treatment choices, and clinical outcomes: randomized controlled trial

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    BACKGROUND: The internet is used for information related to health conditions, including low back pain (LBP), but most LBP websites provide inaccurate information. Few studies have investigated the effectiveness of internet resources in changing health literacy or treatment choices. OBJECTIVE: This study aims to evaluate the effectiveness of the MyBackPain website compared with unguided internet use on health literacy, choice of treatments, and clinical outcomes in people with LBP. METHODS: This was a pragmatic, web-based, participant- and assessor-blinded randomized trial of individuals with LBP stratified by duration. Participants were randomly allocated to have access to the evidence-based MyBackPain website, which was designed with input from consumers and expert consensus or unguided internet use. The coprimary outcomes were two dimensions of the Health Literacy Questionnaire (dimension 2: “having sufficient information to manage my health;” dimension 3: “actively managing my health;” converted to scores 1-100) at 3 months. Secondary outcomes included additional Health Literacy Questionnaire dimensions, quality of treatment choices, and clinical outcomes. RESULTS: A total of 453 participants were recruited, and 321 (70.9%) completed the primary outcomes. Access to MyBackPain was not superior to unguided internet use on primary outcomes (dimension 2: mean difference −0.87 units, 95% CI −3.56 to 1.82; dimension 3: mean difference −0.41 units, 95% CI −2.78 to 1.96). Between-group differences in other secondary outcomes had inconsistent directions and were unlikely to be clinically important, although a small improvement of unclear importance in the quality of stated treatment choices at 1 month was found (mean difference 0.93 units, 95% CI 0.03 to 1.84). CONCLUSIONS: MyBackPain was not superior to unguided internet use for health literacy, but data suggest some short-term improvement in treatment choices. Future research should investigate if greater interactivity and engagement with the website may enhance its impact. TRIAL REGISTRATION: Australian New Zealand Clinical Trials Registry (ANZCTR) ACTRN12617001292369; https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=372926 INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): RR2-10.1136/bmjopen-2018-02751

    Postural strategy and back muscle oxygenation during inspiratory muscle loading.

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    Most healthy individuals show a multisegmental control strategy during challenging standing conditions, whereas others show a rigid ankle-steered strategy, which is assumed as suboptimal. Respiratory-demanding tasks exert a perturbing effect on balance, although the underlying mechanisms remain poorly understood. The purpose of this study was to investigate whether inspiratory resistive loading (IRL) affects postural strategy, back muscle oxygenation, and blood volume during postural control

    Cognitive mediators of the effect of peer victimization on loneliness

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    The impact of stress on psychological adjustment may be mediated by cognitive interpretations (i.e., appraisals) of events for individuals. Defining characteristics of loneliness suggest that appraisals of blame, threat, and perceived control may be particularly important in this domain. AIMS: To evaluate the extent to which cognitive appraisals (perceived control, threat, and blame) can mediate the effect of peer victimization on loneliness. SAMPLE: One hundred and ten children (54 boys, 56 girls) aged 8-12 years attending mainstream schools in Scotland. METHOD: Self-report measures of peer victimization, appraisal, and loneliness. RESULTS: Perceived control partially mediated the effects of peer victimization on loneliness, but neither blame nor threat were mediators. All three measures of control were significantly associated with loneliness at the bivariate level, but only perceived control was significant when the appraisals were entered as predictors in a hierarchical multiple linear regression. CONCLUSIONS: The results highlight the importance of research designs assessing multiple categories of appraisal. Furthermore, they suggest that intervention efforts aiming to combat feelings of loneliness within a peer victimization context should address children's appraisals of perceived control

    Re-examining the consumption-wealth relationship : the role of model uncertainty

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    This paper discusses the consumption-wealth relationship. Following the recent influential workof Lettau and Ludvigson [e.g. Lettau and Ludvigson (2001), (2004)], we use data on consumption, assets andlabor income and a vector error correction framework. Key 
ndings of their work are that consumption doesrespond to permanent changes in wealth in the expected manner, but that most changes in wealth are transitoryand have no e€ect on consumption. We investigate the robustness of these results to model uncertainty andargue for the use of Bayesian model averaging. We 
nd that there is model uncertainty with regards to thenumber of cointegrating vectors, the form of deterministic components, lag length and whether the cointegratingresiduals a€ect consumption and income directly. Whether this uncertainty has important empirical implicationsdepends on the researcher's attitude towards the economic theory used by Lettau and Ludvigson. If we workwith their model, our findings are very similar to theirs. However, if we work with a broader set of models andlet the data speak, we obtain somewhat di€erent results. In the latter case, we 
nd that the exact magnitudeof the role of permanent shocks is hard to estimate precisely. Thus, although some support exists for the viewthat their role is small, we cannot rule out the possibility that they have a substantive role to play
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