439 research outputs found

    AN ALTERNATIVE APPROACH TO THE EVALUATION OF GOAL HIERARCHIES AMONG FARMERS

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    Results of a study of goal orderings of Saskatchewan farmers who participate in the province's FARMLAB Program are presented. We use the method of fuzzy pair-wise comparisons which allows the respondent to indicate a degree of preference between two alternative goal statements, thereby providing more information than in the binary case. From survey data ratio-scale scores are constructed for eight goal statements, and these are regressed on a set of farm enterprise and household characteristics and a psychological locus-of-control (or I-E) score. The empirical results indicate that goodness-of-fit measures are better than those obtained by other researchers, perhaps because a psychological measure (I-E score) is included as an explanatory variable for goal orderings.Farm Management,

    Simulation of ultrasonic lamb wave generation, propagation and detection for an air coupled robotic scanner

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    A computer simulator, to facilitate the design and assessment of a reconfigurable, air-coupled ultrasonic scanner is described and evaluated. The specific scanning system comprises a team of remote sensing agents, in the form of miniature robotic platforms that can reposition non-contact Lamb wave transducers over a plate type of structure, for the purpose of non-destructive evaluation (NDE). The overall objective is to implement reconfigurable array scanning, where transmission and reception are facilitated by different sensing agents which can be organised in a variety of pulse-echo and pitch-catch configurations, with guided waves used to generate data in the form of 2-D and 3-D images. The ability to reconfigure the scanner adaptively requires an understanding of the ultrasonic wave generation, its propagation and interaction with potential defects and boundaries. Transducer behaviour has been simulated using a linear systems approximation, with wave propagation in the structure modelled using the local interaction simulation approach (LISA). Integration of the linear systems and LISA approaches are validated for use in Lamb wave scanning by comparison with both analytic techniques and more computationally intensive commercial finite element/difference codes. Starting with fundamental dispersion data, the paper goes on to describe the simulation of wave propagation and the subsequent interaction with artificial defects and plate boundaries, before presenting a theoretical image obtained from a team of sensing agents based on the current generation of sensors and instrumentation

    ‘I did my bit’: Terrorism, Tarde and the Vehicle-Ramming Attack as an Imitative Event

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    This paper charts the rise in prevalence of ramming attacks and how this wave of attacks challenges many of the assumptions and approaches we have about terrorism, its causes, and policies to address it. Such approaches tend to concentrate on either the ‘psychology’ of individual terrorists, or wider structural issues, such as religious ideology and the role of terrorist organisations in converting and recruiting people to violence. This paper will take a different approach, one which focusses less on structure and individual psychology, and more on the act itself, as something that is not merely an expression of an individual or an ideology, but something that has a lure and force of its own, as something that travels through our contemporary mediascape, to be internalised and imitated by an increasingly varied set of subjects with varying motivations, psychologies, ideologies and circumstances

    The Scotia Science Symposium 2011

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    Introduction to the Scotia Paper

    Assessment and optimisation of STCA performance: Using the Pareto optimal receiver operating characteristic

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    EUROCONTROL Annual Safety R&D Seminar (2008), Southampton, UK, 22-24 October 2008Short Term Conflict Alert (STCA) systems are complex software programs, with many parameters that must be adjusted to achieve best performance. We describe a simple evolutionary algorithm for optimising the trade-off between wanted alerts and nuisance alerts. The procedure yields an estimate of the Pareto optimal Receiver Operating Characteristic for the STCA system and we discuss additional uses of this for characterising and comparing the performance of STCA systems and airspaces

    Self-oriented perfectionism and socially prescribed perfectionism: Differential relationships with intrinsic and extrinsic motivation and test anxiety

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    Previous studies suggest that self-oriented and socially prescribed perfectionism show differential relationships with intrinsic–extrinsic motivation and test anxiety, but the findings are ambiguous. Moreover, they ignored that test anxiety is multidimensional. Consequently, the present study re-investigated the relationships in 104 university students examining how the two forms of perfectionism are related to intrinsic–extrinsic motivation and multidimensional test anxiety (worry, emotionality, interference, lack of confidence, and total anxiety). Regarding motivation, self-oriented perfectionism showed positive correlations with intrinsic reasons for studying, and socially prescribed perfectionism positive correlations with extrinsic reasons. Regarding test anxiety, only socially prescribed perfectionism showed positive correlations with total anxiety. Moreover, socially prescribed perfectionism showed positive correlations with interference and lack of confidence, whereas self-oriented perfectionism showed positive correlations with worry, but negative correlations with interference and lack of confidence. The findings confirm that socially prescribed perfectionism is a maladaptive form of perfectionism associated with extrinsic motivation for studying and higher anxiety in exams. Self-oriented perfectionism, however, is an ambivalent form associated with intrinsic motivation for studying and with both higher and lower anxiety (higher worry, lower interference, lower lack of confidence) in exams

    A validation of the diathesis-stress model for depression in Generation Scotland

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    Abstract Depression has well-established influences from genetic and environmental risk factors. This has led to the diathesis-stress theory, which assumes a multiplicative gene-by-environment interaction (GxE) effect on risk. Recently, Colodro-Conde et al. empirically tested this theory, using the polygenic risk score for major depressive disorder (PRS, genes) and stressful life events (SLE, environment) effects on depressive symptoms, identifying significant GxE effects with an additive contribution to liability. We have tested the diathesis-stress theory on an independent sample of 4919 individuals. We identified nominally significant positive GxE effects in the full cohort (R 2 = 0.08%, p = 0.049) and in women (R 2 = 0.19%, p = 0.017), but not in men (R 2 = 0.15%, p = 0.07). GxE effects were nominally significant, but only in women, when SLE were split into those in which the respondent plays an active or passive role (R 2 = 0.15%, p = 0.038; R 2 = 0.16%, p = 0.033, respectively). High PRS increased the risk of depression in participants reporting high numbers of SLE (p = 2.86 × 10−4). However, in those participants who reported no recent SLE, a higher PRS appeared to increase the risk of depressive symptoms in men (ÎČ = 0.082, p = 0.016) but had a protective effect in women (ÎČ = −0.061, p = 0.037). This difference was nominally significant (p  = 0.017). Our study reinforces the evidence of additional risk in the aetiology of depression due to GxE effects. However, larger sample sizes are required to robustly validate these findings

    Convergent consequences of parthenogenesis on stick insect genomes

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    International audienceThe shift from sexual reproduction to parthenogenesis has occurred repeatedly in animals, but how the loss of sex affects genome evolution remains poorly understood. We generated reference genomes for five independently evolved parthenogenetic species in the stick insect genus Timema and their closest sexual relatives. Using these references and population genomic data, we show that parthenogenesis results in an extreme reduction of heterozygosity and often leads to genetically uniform populations. We also find evidence for less effective positive selection in parthenogenetic species, suggesting that sex is ubiquitous in natural populations because it facilitates fast rates of adaptation. Parthenogenetic species did not show increased transposable element (TE) accumulation, likely because there is little TE activity in the genus. By using replicated sexual-parthenogenetic comparisons, our study reveals how the absence of sex affects genome evolution in natural populations, providing empirical support for the negative consequences of parthenogenesis as predicted by theory

    Genome of the rams horn snail Biomphalaria straminea : an obligate intermediate host of schistosomiasis

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    This work was supported by the Hong Kong Research Grant Council Collaborative Research Fund (C4015-20EF), General Research Fund (14100919), NSFC/RGC Joint Research Scheme (N_CUHK401/21), and The Chinese University of Hong Kong Direct Grant (4053433, 4053489). Y.Y., W.L.S., C.F.W., S.T.S.L., and Y.L. were supported by the Ph.D. studentships of The Chinese University of Hong Kong. A.H. is supported by a Biotechnology and Biological Sciences Research Council (BBSRC) David Phillips Fellowship (BB/N020146/1). T.B. is supported by a studentship from the Biotechnology and Biological Sciences Research Council-funded South West Biosciences Doctoral Training Partnership (BB/M009122/1). M.E.A.R. is supported by a Ph.D. studentship from the School of Biology and St Andrews University.Background: Schistosomiasis, or bilharzia, is a parasitic disease caused by trematode flatworms of the genus Schistosoma. Infection by Schistosoma mansoni in humans results when cercariae emerge into water from freshwater snails in the genus Biomphalaria and seek out and penetrate human skin. The snail Biomphalaria straminea is native to South America and is now also present in Central America and China, and represents a potential vector host for spreading schistosomiasis. To date, genomic information for the genus is restricted to the neotropical species Biomphalaria glabrata. This limits understanding of the biology and management of other schistosomiasis vectors, such as B. straminea. Findings: Using a combination of Illumina short‐read, 10X Genomics linked‐read, and Hi‐C sequencing data, our 1.005 Gb B. straminea genome assembly is of high contiguity, with a scaffold N50 of 25.3 Mb. Transcriptomes from adults were also obtained. Developmental homeobox genes, hormonal genes, and stress-response genes were identified, and repeat content was annotated (40.68% of genomic content). Comparisons with other mollusc genomes (including Gastropoda, Bivalvia, and Cephalopoda) revealed syntenic conservation, patterns of homeobox gene linkage indicative of evolutionary changes to gene clusters, expansion of heat shock protein genes, and the presence of sesquiterpenoid and cholesterol metabolic pathway genes in Gastropoda. In addition, hormone treatment together with RT-qPCR assay reveal a sesquiterpenoid hormone responsive system in B. straminea, illustrating that this renowned insect hormonal system is also present in the lophotrochozoan lineage. Conclusion: This study provides the first genome assembly for the snail B. straminea and offers an unprecedented opportunity to address a variety of phenomena related to snail vectors of schistosomiasis, as well as evolutionary and genomics questions related to molluscs more widely.Publisher PDFPeer reviewe

    The ENIGMA Stroke Recovery Working Group: Big data neuroimaging to study brain–behavior relationships after stroke

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    The goal of the Enhancing Neuroimaging Genetics through Meta‐Analysis (ENIGMA) Stroke Recovery working group is to understand brain and behavior relationships using well‐powered meta‐ and mega‐analytic approaches. ENIGMA Stroke Recovery has data from over 2,100 stroke patients collected across 39 research studies and 10 countries around the world, comprising the largest multisite retrospective stroke data collaboration to date. This article outlines the efforts taken by the ENIGMA Stroke Recovery working group to develop neuroinformatics protocols and methods to manage multisite stroke brain magnetic resonance imaging, behavioral and demographics data. Specifically, the processes for scalable data intake and preprocessing, multisite data harmonization, and large‐scale stroke lesion analysis are described, and challenges unique to this type of big data collaboration in stroke research are discussed. Finally, future directions and limitations, as well as recommendations for improved data harmonization through prospective data collection and data management, are provided
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