99 research outputs found

    Ageing is associated with disrupted reinforcement learning whilst learning to help others is preserved.

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    Funder: Wellcome Trust (Wellcome); doi: https://doi.org/10.13039/100004440Funder: DH | National Institute for Health Research (NIHR); doi: https://doi.org/10.13039/501100000272Funder: Christ Church Junior Research Fellowship Christ Church Research Centre GrantReinforcement learning is a fundamental mechanism displayed by many species. However, adaptive behaviour depends not only on learning about actions and outcomes that affect ourselves, but also those that affect others. Using computational reinforcement learning models, we tested whether young (age 18-36) and older (age 60-80, total n = 152) adults learn to gain rewards for themselves, another person (prosocial), or neither individual (control). Detailed model comparison showed that a model with separate learning rates for each recipient best explained behaviour. Young adults learned faster when their actions benefitted themselves, compared to others. Compared to young adults, older adults showed reduced self-relevant learning rates but preserved prosocial learning. Moreover, levels of subclinical self-reported psychopathic traits (including lack of concern for others) were lower in older adults and the core affective-interpersonal component of this measure negatively correlated with prosocial learning. These findings suggest learning to benefit others is preserved across the lifespan with implications for reinforcement learning and theories of healthy ageing

    Zoonosis emergence linked to agricultural intensification and environmental change

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    A systematic review was conducted by a multidisciplinary team to analyze qualitatively best available scientific evidence on the effect of agricultural intensification and environmental changes on the risk of zoonoses for which there are epidemiological interactions between wildlife and livestock. The study found several examples in which agricultural intensification and/or environmental change were associated with an increased risk of zoonotic disease emergence, driven by the impact of an expanding human population and changing human behavior on the environment. We conclude that the rate of future zoonotic disease emergence or reemergence will be closely linked to the evolution of the agriculture–environment nexus. However, available research inadequately addresses the complexity and interrelatedness of environmental, biological, economic, and social dimensions of zoonotic pathogen emergence, which significantly limits our ability to predict, prevent, and respond to zoonotic disease emergence

    Discourse constraints on prosodic marking in lexical replacement repair

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    This paper reports on an investigation of instances of lexical replacement repair, in which a speaker replaces one lexical choice with another, sampled from Dutch spontaneous interaction. The study is driven by the question as to what motivates a speaker to produce a particular instance of self-repair with or without ‘prosodic marking’ ― with or without notable prosodic prominence ― and the notion that a close consideration of the discourse context in which the repair is embedded, and its function in that context, is paramount in addressing this question. The study explores the empirical grounds for two proposals regarding the function of prosodic marking: one in which marking is a response to the speaker’s embarrassment or unease at the error or infelicity, and one in which marking is done for the listener’s benefit, to highlight particularly important information. This paper describes three discourse contexts in which prosodic marking is notably common, and argues that both proposals find some support in these contexts. The analysis suggests that speakers’ decisions for or against prosodic marking are based at least on considerations of epistemic authority, precision and exaggeration, and discourse coherence

    Memory Self-Efficacy in its Social Cognitive Context

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    This chapter takes a primarily cognitive construct - memory self-efficacy (MSE) - and returns it to its roots - social cognition (Bandura, 1986). This is a natural and obvious move. MSE has evolved since the mid-1980s (Berry, West, & Powlishta, 1986; Hertzog, Dixon, Schulenberg, & Hultsch, 1987) to its present identity and status in the cognitive aging and adult developmental research literature. If it is to avoid becoming a hypothesis in search of data (Light, 1991) or worse, an epiphenomenon to more robust explanations of cognitive aging (e.g., speed) (Salthouse, 1993), its potential and limits must be scrutinized and subjected to rigorous new research agendas. Arguably, MSE has arrived at its present destination via metamemory (Dixon, Hertzog, & Hultsch, 1986; Hertzog, Dixon, & Hultsch, 1990a; Hertzog et al., 1987; Hultsch, Hertzog, Dixon, & Davidson, 1988), thereby acquiring a more cognitive emphasis than its clinical and social underpinnings suggest. This chapter presents MSE research from my lab that has been conducted from the orienting framework of self-efficacy theory and methodology (Bandura, 1977, 1986, 1997; Bandura, Adams, Hardy, & Howells, 1980; Bandura, Reese, & Adams, 1982). The value of this framework lies in its rich theoretical foundation, its unique measurement approach, and its ties to social cognition. The goal of the chapter is to evaluate the present status of MSE research and to suggest new research directions

    Random forests to evaluate interspecific interactions in fish distribution models

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    [EN] Previous research indicated that high predictive performance in species distribution modelling can be obtained by combining both biotic and abiotic habitat variables. However, models developed for fish often only address physical habitat characteristics, thus omitting potentially important biotic factors. Therefore, we assessed the impact of biotic variables on fish habitat preferences in four selected stretches of the upper Cabriel River (E Spain). The occurrence of Squalius pyrenaicus and Luciobarbus guiraonis was related to environmental variables describing biotic interactions (inferred by relationships among fish abundances) and channel hydro-morphological characteristics. Random Forests (RF) models were trained and then validated using independent datasets. To build RF models, the conditional variable importance was used together with the model improvement ratio technique. The procedure showed effectiveness in identifying a parsimonious set of not correlated variables, which minimize noise and improve model performance in both training and validation phases. Water depth, channel width, fine substrate and water-surface gradient were selected as most important habitat variables for both fish. Results showed clear habitat overlapping between fish species and suggest that competition is not a strong factor in the study area.This research has been developed in the framework of the HolRiverMed project (FP7-PEOPLE-2010-275577, Marie Curie Actions, Intra-European Fellowships) and the SCARCE project (Assessing and predicting effects on water quantity and quality in Iberian rivers caused by global change, Consolider-Ingenio 2010 CSD2009-00065). Data collection was partially funded by the Spanish Ministry of Environment, Rural and Marine Affairs, the Jucar River Basin District Authority and the Spanish Ministry of Education and Science (POTECOL, CGL2007-66412). We thank Juan Diego Alacaraz-Hernandez, Matias Peredo-Parada and Aina Hernandez-Mascarell for their help with field work and suggestions on data analysis.Vezza, P.; Muñoz Mas, R.; Martinez-Capel, F.; Mouton, A. (2015). Random forests to evaluate interspecific interactions in fish distribution models. Environmental Modelling and Software. 67:173-183. https://doi.org/10.1016/j.envsoft.2015.01.005S1731836

    Multicenter Phase 2 Trial of Sirolimus for Tuberous Sclerosis: Kidney Angiomyolipomas and Other Tumors Regress and VEGF- D Levels Decrease

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    Tuberous sclerosis (TSC) related tumors are characterized by constitutively activated mTOR signaling due to mutations in TSC1 or TSC2.We completed a phase 2 multicenter trial to evaluate the efficacy and tolerability of the mTOR inhibitor, sirolimus, for the treatment of kidney angiomyolipomas.36 adults with TSC or TSC/LAM were enrolled and started on daily sirolimus. The overall response rate was 44.4% (95% confidence intervals [CI] 28 to 61); 16/36 had a partial response. The remainder had stable disease (47.2%, 17/36), or were unevaluable (8.3%, 3/36). The mean decrease in kidney tumor size (sum of the longest diameters [sum LD]) was 29.9% (95% CI, 22 to 37; n = 28 at week 52). Drug related grade 1-2 toxicities that occurred with a frequency of >20% included: stomatitis, hypertriglyceridemia, hypercholesterolemia, bone marrow suppression (anemia, mild neutropenia, leucopenia), proteinuria, and joint pain. There were three drug related grade 3 events: lymphopenia, headache, weight gain. Kidney angiomyolipomas regrew when sirolimus was discontinued but responses tended to persist if treatment was continued after week 52. We observed regression of brain tumors (SEGAs) in 7/11 cases (26% mean decrease in diameter), regression of liver angiomyolipomas in 4/5 cases (32.1% mean decrease in longest diameter), subjective improvement in facial angiofibromas in 57%, and stable lung function in women with TSC/LAM (n = 15). A correlative biomarker study showed that serum VEGF-D levels are elevated at baseline, decrease with sirolimus treatment, and correlate with kidney angiomyolipoma size (Spearman correlation coefficient 0.54, p = 0.001, at baseline).Sirolimus treatment for 52 weeks induced regression of kidney angiomyolipomas, SEGAs, and liver angiomyolipomas. Serum VEGF-D may be a useful biomarker for monitoring kidney angiomyolipoma size. Future studies are needed to determine benefits and risks of longer duration treatment in adults and children with TSC.Clinicaltrials.gov NCT00126672

    Spatial distribution and risk factors of Brucellosis in Iberian wild ungulates

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    <p>Abstract</p> <p>Background</p> <p>The role of wildlife as a brucellosis reservoir for humans and domestic livestock remains to be properly established. The aim of this work was to determine the aetiology, apparent prevalence, spatial distribution and risk factors for brucellosis transmission in several Iberian wild ungulates.</p> <p>Methods</p> <p>A multi-species indirect immunosorbent assay (iELISA) using <it>Brucella </it>S-LPS antigen was developed. In several regions having brucellosis in livestock, individual serum samples were taken between 1999 and 2009 from 2,579 wild bovids, 6,448 wild cervids and4,454 Eurasian wild boar (<it>Sus scrofa</it>), and tested to assess brucellosis apparent prevalence. Strains isolated from wild boar were characterized to identify the presence of markers shared with the strains isolated from domestic pigs.</p> <p>Results</p> <p>Mean apparent prevalence below 0.5% was identified in chamois (<it>Rupicapra pyrenaica</it>), Iberian wild goat (<it>Capra pyrenaica</it>), and red deer (<it>Cervus elaphus</it>). Roe deer (<it>Capreolus capreolus</it>), fallow deer (<it>Dama dama</it>), mouflon (<it>Ovis aries</it>) and Barbary sheep (<it>Ammotragus lervia</it>) tested were seronegative. Only one red deer and one Iberian wild goat resulted positive in culture, isolating <it>B. abortus </it>biovar 1 and <it>B. melitensis </it>biovar 1, respectively. Apparent prevalence in wild boar ranged from 25% to 46% in the different regions studied, with the highest figures detected in South-Central Spain. The probability of wild boar being positive in the iELISA was also affected by age, age-by-sex interaction, sampling month, and the density of outdoor domestic pigs. A total of 104 bacterial isolates were obtained from wild boar, being all identified as <it>B. suis </it>biovar 2. DNA polymorphisms were similar to those found in domestic pigs.</p> <p>Conclusions</p> <p>In conclusion, brucellosis in wild boar is widespread in the Iberian Peninsula, thus representing an important threat for domestic pigs. By contrast, wild ruminants were not identified as a significant brucellosis reservoir for livestock.</p
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