1,308 research outputs found

    Discovering predictive variables when evolving cognitive models

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    A non-dominated sorting genetic algorithm is used to evolve models of learning from different theories for multiple tasks. Correlation analysis is performed to identify parameters which affect performance on specific tasks; these are the predictive variables. Mutation is biased so that changes to parameter values tend to preserve values within the population's current range. Experimental results show that optimal models are evolved, and also that uncovering predictive variables is beneficial in improving the rate of convergence

    Fish stocking programs: assessing the benefits against long term impacts

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    OBJECTIVES: 1. Assess movements and ecological impacts of stocked barramundi in a model river and impoundment 2. Determine if barramundi stocking has any discernable adverse genetic impacts on wild populations in a previously stocked river syste

    perceiving animacy and arousal in transformed displays of human interaction

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    When viewing a moving abstract stimulus, people tend to attribute social meaning and purpose to the movement. The classic work of Heider and Simmel [1] investigated how observers would describe movement of simple geometric shapes (circle, triangles, and a square) around a screen. A high proportion of participants reported seeing some form of purposeful interaction between the three abstract objects and defining this interaction as a social encounter. Various papers have subsequently found similar results [2,3] and gone on to show that, as Heider and Simmel suggested, the phenomenon was due more to the relationship in space and time of the objects, rather than any particular object characteristic. The research of Tremoulet and Feldman [4] has shown that the percept of animacy may be elicited with a solitary moving object. They asked observers to rate the movement of a single dot or rectangle for whether it was under the influence of an external force, or whether it was in control of its own motion. At mid-trajectory the shape would change speed or direction, or both. They found that shapes that either changed direction greater than 25 degrees from the original trajectory, or changed speed, were judged to be "more alive" than others. Further discussion and evidence of animacy with one or two small dots can be found in Gelman, Durgin and Kaufman [5] Our aim was to further study this phenomenon by using a different method of stimulus production. Previous methods for producing displays of animate objects have relied either on handcrafted stimuli or on parametric variations of simple motion patterns. It is our aim to work towards a new automatic approach by taking actual human movements, transforming them into basic shapes, and exploring what motion properties need to be preserved to obtain animacy. Though the phenomenon of animacy has been shown for many years, using various different displays, very few specific criteria have been set on the essential characteristics of the displays. Part of this research is to try and establish what movements result in percepts of animacy, and in turn, to give further understanding of essential characteristics of human movement and social interaction. In this paper we discuss two experiments in which we examine how different transformations of an original video of a dance influences perception of animacy. We also examine reports of arousal, Experiment 1, and emotional engagement in Experiment 2

    Encouraging children to mentalise about a perceived outgroup increases prosocial behaviour towards outgroup members

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    We investigated whether encouraging young children to discuss the mental states of an immigrant group would elicit more prosocial behaviour towards them and impact on their perception of a group member’s emotional experience. Five- and 6-year-old children were either prompted to talk about the thoughts and feelings of this social group or to talk about their actions. Across two studies, we found that this manipulation increased the extent to which children shared with a novel member of the immigrant group who was the victim of a minor transgression. The manipulation did not lead to greater sharing towards a victim from the children’s own culture and did not influence their perception of a victim’s negative emotions. These results may ultimately have implications for interventions aimed at fostering positive intergroup relations within the context of immigration

    A method for isolating and culturing placental cells from failed early equine pregnancies

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    Early pregnancy loss occurs in 6–10% of equine pregnancies making it the main cause of reproductive wastage. Despite this, reasons for the losses are known in only 16% of cases. Lack of viable conceptus material has inhibited investigations of many potential genetic and pathological causes. We present a method for isolating and culturing placental cells from failed early equine pregnancies. Trophoblast cells from 18/30 (60%) failed equine pregnancies of gestational ages 14–65 days were successfully cultured in three different media, with the greatest growth achieved for cells cultured in AmnioChrome™ Plus. Genomic DNA of a suitable quality for molecular assays was also isolated from 29/30 of these cases. This method will enable future investigations determining pathologies causing EPL

    Risk accuracy of type 2 diabetes in middle aged adults: Associations with sociodemographic, clinical, psychological and behavioural factors

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    Objective To identify the proportion of individuals with an accurate perception of their risk of type 2 diabetes (T2D) prior to, immediately after and eight weeks after receiving a personalised risk estimate. Additionally, we aimed to explore what factors are associated with underestimation and overestimation immediately post-intervention. Methods Cohort study based on the data collected in the Diabetes Risk Communication Trial. We included 379 participants (mean age 48.9 (SD 7.4) years; 55.1 women) who received a genotypic or phenotypic risk estimate for T2D. Results While only 1.3 of participants perceived their risk accurately at baseline, this increased to 24.7 immediately after receiving a risk estimate and then dropped to 7.3 at eight weeks. Those who overestimated their risk at baseline continued to overestimate it, whereas those who underestimated their risk at baseline improved their risk accuracy. We did not identify any other characteristics associated with underestimation or overestimation immediately after receiving a risk estimate. Conclusion Understanding a received risk estimate is challenging for most participants with many continuing to have inaccurate risk perception after receiving the estimate. Practice implications Individuals who overestimate or underestimate their T2D risk before receiving risk information might require different approaches for altering their risk perception. © 2017 The Author

    Effective action approach and Carlson-Goldman mode in d-wave superconductors

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    We theoretically investigate the Carlson-Goldman (CG) mode in two-dimensional clean d-wave superconductors using the effective ``phase only'' action formalism. In conventional s-wave superconductors, it is known that the CG mode is observed as a peak in the structure factor of the pair susceptibility S(Ω,K)S(\Omega, \mathbf{K}) only just below the transition temperature T_c and only in dirty systems. On the other hand, our analytical results support the statement by Y.Ohashi and S.Takada, Phys.Rev.B {\bf 62}, 5971 (2000) that in d-wave superconductors the CG mode can exist in clean systems down to the much lower temperatures, T0.1TcT \approx 0.1 T_c. We also consider the manifestations of the CG mode in the density-density and current-current correlators and discuss the gauge independence of the obtained results.Comment: 23 pages, RevTeX4, 12 EPS figures; final version to appear in PR
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