1,440 research outputs found

    Discrete choice modelling incorporating attribute thresholds of perception

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    In this paper we formulate a discrete choice model that incorporates thresholds in the perception of attribute changes. The model considers multiple options and allows changes in several attributes. We postulate that if thresholds exist they could be random, differ between individuals, and even be a function of socio-economic characteristics and choice conditions. Our formulation allows estimation of the parameters of the threshold probability distribution starting from information about choices. The model is applied to synthetic data and also to real data from a stated preference survey. We found that where perception thresholds exist in the population, the use of models without them leads to errors in estimation and prediction. Clearly, the effect is more relevant when the typical size of change in the attribute value is comparable with the threshold, and when the contribution of this attribute in the utility function is substantial. Finally, we discuss the implications of the threshold model for estimation of the benefits of transport investments, and show that where thresholds exist, models that do not represent them can overestimate benefits substantially

    Features of alterations of igneous rocks from Sierras of Guadarrama and Malagon (Spanish Central Range)

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    [Resumen] Se describen las características-de las alteraciones desarrolladas sobre las rocas ígneas de un sector del Sistema Central. Criterios geomorfológicos y su distinta composición mineralógica permiten suponer su origen a partir de distintas etapas de alteración. Se discuten las condiciones climáticas durante su formación, realizada siempre bajo climas poco agresivos.[Abstract] The main features of the alterations developped on igneous rocks of Central System are described. From geomorphological criteria as well as mineralogical data, different stages of weathering are been inferred. Although weathering processes have not been strong, different conditions are discussed for each stage

    Stress-induced nuclear accumulation is dispensable for Hog1-dependent gene expression and virulence in a fungal pathogen

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    The authors thank E. Veal for intellectual input. This work was funded by the UK Biotechnology and Biological Research Council [J.Q. BB/K016393/1; A.J.P.B. BB/K017365/1], the National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs) [D.M.M. NC/N002482/1] and the Wellcome Trust Strategic Award in Medical Mycology and Fungal Immunology [097377]). D.M.M. and A.J.P.B. are also supported by the MRC Centre for Medical Mycology at the University of Aberdeen (MR/N006364/1).Peer reviewedPublisher PD

    Sfp1 and Rtg3 reciprocally modulate carbon source-conditional stress adaptation in the pathogenic yeast Candida albicans

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    Acknowledgements We thank Aaron Mitchell, Dominique Sanglard and Suzanne Noble for their generosity in providing mutant collections, and Linghuo Jiang for generously providing strains. We also thank Susan Budge for her support and excellent technical assistance. We also thank the qPCR Facility in the Institute of Medical Sciences, and particularly Fiona Saunders for her great advice and help. SLK was supported by a PhD scholarship from the University of Aberdeen. AJPB was supported by the UK Biotechnology and Biological Research Council (BB/F00513X/1; BB/K017365/1), by the European Research Council (STRIFE Advanced Grant; ERC-2009-AdG-249793), and by the UK Medical Research Council (MR/M026663/1). AJPB and CAM were also supported by the Wellcome Trust (088858; 097377), and by the MRC Centre for Medical Mycology and the University of Aberdeen (MR/N006364/1).Peer reviewedPublisher PD

    A study of the relationship between parental mediation and adolescents' digital skills, online risks and online opportunities

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    In recent years, discussions have sparked about the risks and opportunities that digital technologies may have for adolescents. Some researchers argue that the best way to increase online opportunities and avoid online risks is to increase adolescents' digital skills. For this reason, the first goal of this study was to examine how adolescents' digital skills are related to their online opportunities and online risks behaviours. A second goal was to examine the influence of two ways of parental mediation (active and restrictive) on the level of teenagers’ digital skills, and subsequently their online opportunities and online risks. Finally, we intended to establish the validity and the structure of the Digital Literacy Scale. Using data from a cross-sectional survey of 1.446 Spanish secondary school pupils, we found that more digitally skilled adolescents take more opportunities, and experience more risks. Digital literacy mediates the relationship between restrictive (but not of active) parental mediation and online risks and opportunities. Furthermore, the Digital Literacy Scale was shown to be valid in terms of construct validity. The findings suggest that digital literacy remains essential as it lets teenagers take more opportunities, and that parents should opt for other ways of mediation rather than restrictive mediation

    Approach to the concept of quaternary prevention in Genetics and Clinical Dysmorphology.

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    Dismorfología, Citogenética y Clínica: Resultados de estudios sobre los datos del ECEMCPreventive medicine is an important area of health care, mainly in Primary Health Care. Because it is acted on healthy people (in Genetics and Dysmorphology mainly in foetal and neonatal period), preventive medicine needs even stronger supporting evidence (on benefits, harms and costs) than therapeutic and/or diagnostic interventions. The aims of this article are: a) to present the theorical concepts related to screening test in Genetics and Dysmorphology for early diseases detection, with special attention to main potential harm in overdiagnosis (false positive), causing unnecessary anxiety and intervention, and also to screening bias; and b) to present the interesting relation between preventive medicine with two new concepts (quaternary prevention and cascade effect), because it is important to know the clinical and ethical implications of screening programmes and to achieve and evidence-based decision-making in this outstanding area of health. Quaternary prevention is a new concept in preventive medicine (beyond the classical primary, secondary and tertiary prevention) whose objective is to avoid and/or to diminish the unnecessary medical intervention, and is the practical version of the "primum non nocere". Quaternary prevention has a multifactorial origin, in relation to social, cultural, economic, political and/or medical factors. Today, we have the danger to happen towards the "risk culture" and, consequently, to the diagnostic, therapeutic and/or preventive excess, named as cascade effect, with clinical and ethical implications in medical practice. Genetic testing of children is an interesting field in this area of preventive medicine. It is clearly appropriate to perform genetic testing of minors when the problem in question can be rectified, treated, or prevented but the decision is difficult when the risk from the test may be significant, the statistical risk of disease is minimal, and the benefit or early diagnosis is small. Hereditary haemochromatosis, by example, would seem to be an ideal disease for community population-screening with genetic testing, but the major concerns have been the uncertainty surrounding the natural history of untreated disease, informed consent, labelling and stigmatisation among participants that may never develop illness, and genetic discrimination. In Dysmorphology is interesting to know the real value of "guide signs" for posterior diagnostic and screening tests, and we expose to examples on the matter: developmental dysplasia of the hip and Prader-Willi syndrome.N

    Social Pressure or Rational Reactions to Incentives? A Historical Analysis of Reasons for Referee Bias in the Spanish Football

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    A relevant question in social science is whether cognitive bias can be instigated by social pressure or is it just a rational reaction to incentives in place. Sport, and association football in particular, offers settings in which to gain insights into this question. In this paper we estimate the determinants of the length of time between referee appointments in Spanish soccer as a function of referee decisions in favour of the home and away team in the most recent match by means of a deep-learning model. This approach allows us to capture all interactions among a high-dimensional set of variables without the necessity of specifying them beforehand. Furthermore, deep-learning models are nowadays the state of the art among the predicting models which are needed and here used for estimating effects of a cause. We do not find strong evidence of an incentive scheme that counteracts well-known home referee biases. Our results also suggest that referees are incentivised to deliver a moderate amount of surprise in the outcome of the game what is consistent with the objective function of consumers and tournament organisers

    Estimating the value of risk reduction for pedestrians in the road environment: An exploratory analysis

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    In recent years there has been a re-focus on the valuation of a statistical life from the ex post or human capital method to an ex ante willingness to pay (WTP) approach. This is in part a recognition that we need to focus on establishing the amount, ex ante, that individuals are willing to pay to reduce the risk of exposure to circumstances that might lead to death or degree of injury in the road environment. This study sets out a framework in which to identify the degree of preference heterogeneity in WTP of pedestrians to avoid being killed or injured. A stated choice experiment approach is developed. The empirical setting is a choice of walking route for a particular trip that a sample of pedestrians periodically undertakes in Australia. Mixed logit models are estimated to obtain the marginal (dis)utilities associated with each influence on the choice amongst the attribute packages offered in the stated choice scenarios. These conditional estimates are used to obtain the WTP distributions for fatality and classes of injury avoidance, which are then aggregated to obtain estimates for pedestrians of the value of risk reduction (VRR)
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