452 research outputs found

    Did tool-use evolve with enhanced physical cognitive abilities?

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    The use and manufacture of tools have been considered to be cognitively demanding and thus a possible driving factor in the evolution of intelligence. In this study, we tested the hypothesis that enhanced physical cognitive abilities evolved in conjunction with the use of tools, by comparing the performance of naturally tool-using and non-tool-using species in a suite of physical and general learning tasks. We predicted that the habitually tool-using species, New Caledonian crows and GalĂĄpagos woodpecker finches, should outperform their non-tool-using relatives, the small tree finches and the carrion crows in a physical problem but not in general learning tasks. We only found a divergence in the predicted direction for corvids. That only one of our comparisons supports the predictions under this hypothesis might be attributable to different complexities of tool-use in the two tool-using species. A critical evaluation is offered of the conceptual and methodological problems inherent in comparative studies on tool-related cognitive abilities

    Accelerated Projected Gradient Method for Linear Inverse Problems with Sparsity Constraints

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    Regularization of ill-posed linear inverse problems via ℓ1\ell_1 penalization has been proposed for cases where the solution is known to be (almost) sparse. One way to obtain the minimizer of such an ℓ1\ell_1 penalized functional is via an iterative soft-thresholding algorithm. We propose an alternative implementation to ℓ1\ell_1-constraints, using a gradient method, with projection on ℓ1\ell_1-balls. The corresponding algorithm uses again iterative soft-thresholding, now with a variable thresholding parameter. We also propose accelerated versions of this iterative method, using ingredients of the (linear) steepest descent method. We prove convergence in norm for one of these projected gradient methods, without and with acceleration.Comment: 24 pages, 5 figures. v2: added reference, some amendments, 27 page

    Liver Enzymes: Interaction Analysis of Smoking with Alcohol Consumption or BMI, Comparing AST and ALT to Îł-GT

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    A detrimental interaction between smoking and alcohol consumption with respect serum Îł-glutamyltransferase (Îł-GT) has recently been described. The underlying mechanisms remain unknown. The present work aimed to provide further insights by examining similar interactions pertaining to aspartate and alanine transaminase (AST, ALT), routine liver markers less prone to enzyme induction.<0.0001). The interactions all were in the same directions as for Îł-GT, i.e. synergistic with alcohol and opposite with BMI.The patterns of interaction between smoking and alcohol consumption or BMI with respect to AST and ALT resembled those observed for Îł-GT. This renders enzyme induction a less probable mechanism for these associations, whereas it might implicate exacerbated hepatocellular vulnerability and injury

    Reliability and validity study of Persian modified version of MUSIC (musculoskeletal intervention center) – Norrtalje questionnaire

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    <p>Abstract</p> <p>Background</p> <p>Musculoskeletal disorders (MSDs) are a major health problem in the world. Self-reported questionnaires are a known method for estimating the prevalence of MSDs among the population. One of the studies concerning MSDs and their relation to work-related physical and psychosocial factors, as well as non-work-related factors, is the MUSIC-Norrtalje study in Sweden. In this study, the research group developed a questionnaire, which has been validated during its development process and is now considered a well-known instrument. The aim of this study is to validate the Persian version of this questionnaire.</p> <p>Methods</p> <p>The first step was to establish two expert panel groups in Iran and Sweden. The Focus Group Discussion (FGD) method was used to detect questionnaire face and content validity. To detect questionnaire reliability, we used the test-retest method.</p> <p>Results</p> <p>Except for two items, all other questions that respondents had problems with in the focus group (20 of 297), had unclear translations; the ambiguity was related to the stem of the questions and the predicted answers were clear for the participants. The concepts of 'household/spare time' and 'physical activity in the workplace' were not understood by the participants of FGD; this has been solved by adding further descriptions to these phrases in the translation. In the test-retest study, the reliability coefficient was relatively high in most items (only 5 items out of 297 had an ICC or kappa below 0.7).</p> <p>Conclusion</p> <p>The findings from the present study provide evidence that the Persian version of the MUSIC questionnaire is a reliable and valid instrument.</p

    Occupational exposure assessment in case-control studies: opportunities for improvement

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    Community based case-control studies are an efficient means to study disease aetiologies, and may be the only practical means to investigate rare diseases. However, exposure assessment remains problematic. We review the literature on the validity and reliability of common case-control exposure assessment methods: occupational histories, job-exposure matrices (JEMs), self reported exposures, and expert assessments. Given the variable quality of current exposure assessment techniques, we suggest methods to improve assessments, including the incorporation of hygiene measurements: using data from administrative exposure databases; using results of studies identifying determinants of exposure to develop questionnaires; and where reasonable given latency and biological half life considerations, directly measuring exposures of study subjects

    Occupational, domestic and environmental mesothelioma risks in the British population: a case–control study

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    We obtained lifetime occupational and residential histories by telephone interview with 622 mesothelioma patients (512 men, 110 women) and 1420 population controls. Odds ratios (ORs) were converted to lifetime risk (LR) estimates for Britons born in the 1940s. Male ORs (95% confidence interval (CI)) relative to low-risk occupations for >10 years of exposure before the age of 30 years were 50.0 (25.8–96.8) for carpenters (LR 1 in 17), 17.1 (10.3–28.3) for plumbers, electricians and painters, 7.0 (3.2–15.2) for other construction workers, 15.3 (9.0–26.2) for other recognised high-risk occupations and 5.2 (3.1–8.5) in other industries where asbestos may be encountered. The LR was similar in apparently unexposed men and women (∌1 in 1000), and this was approximately doubled in exposed workers' relatives (OR 2.0, 95% CI 1.3–3.2). No other environmental hazards were identified. In all, 14% of male and 62% of female cases were not attributable to occupational or domestic asbestos exposure. Approximately half of the male cases were construction workers, and only four had worked for more than 5 years in asbestos product manufacture

    What does regional studies study? From subnational to supra-national regional spaces or Grossraum of sovereign governance

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    This article makes a case for expanding the scope of current versions of “regional studies” to include greater emphasis upon transnational regions as of equal if not greater importance compared with an exclusive focus upon sub-national regions. The latter more restrictive approach is typically predicated on the continued centrality of state borders against which the dominant notion of regions as subnational entities is constituted and reiterated. Drawing upon a case study of the African Union our study provides a framework, a critically revised Grossraum theory, for addressing the emergence of a new pluralistic and multipolar world order characterised by supra-national regions and regional organizations. Traditional Schmittian notions of Grossraum are shown to be in need of substantial revision before they are able to adequately accommodate and explain the empirical details of our case study
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