18 resultados para Lifespan Extension

em Aston University Research Archive


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The Saccharomyces cerevisiae gene FPS1 encodes an aquaglyceroporin of the major intrinsic protein (MIP) family. The main function of Fps1p seems to be the efflux of glycerol in the adaptation of the yeast cell to lower external osmolarity. Fps1p is an atypical member of the family, because the protein is much larger (669 amino acids) than most MIPs due to long hydrophilic extensions in both termini. We have shown previously that a short domain in the N-terminal extension of the protein is required for restricting glycerol transport through the channel (Tamás, M. J., Karlgren, S., Bill, R. M., Hedfalk, K., Allegri, L., Ferreira, M., Thevelein, J. M., Rydström, J., Mullins, J. G. L., and Hohmann, S. (2003) J. Biol. Chem. 278, 6337-6345). Deletion of the N-terminal domain results in an unregulated channel, loss of glycerol, and osmosensitivity. In this work we have investigated the role of the Fps1p C terminus (139 amino acids). A set of eight truncations has been constructed and tested in vivo in a yeast fps1Δ strain. We have performed growth tests, membrane localization following cell fractionation, and glycerol accumulation measurements as well as an investigation of the osmotic stress response. Our results show that the C-terminal extension is also involved in restricting transport through Fps1p. We have identified a sequence of 12 amino acids, residues 535-546, close to the sixth transmembrane domain. This element seems to be important for controlling Fps1p function. Similar to the N-terminal domain, the C-terminal domain is amphiphilic and has a potential to dip into the membrane.

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Primary data obtained from unionized employees in Singapore were used to examine P. A. Bamberger, A. N. Kluger, and R. Suchard's (1999) integrative model of the antecedents and outcomes of union commitment. Structural equation modeling results revealed support for their integrative model. Specifically, the results revealed the influence of job satisfaction on union loyalty to be indirect through organizational commitment. However, the union-related antecedents (union socialization and union instrumentality) were both directly and indirectly related to union loyalty through pro-union attitudes. In addition, union loyalty was related to the individually and organizationally directed union citizenship behavior dimensions. Limitations of the study and implications of the findings are discussed.

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The research described in this study replicates and extends the Brady et al., [Brady, M. K., Knight, G. A., Cronin Jr. J. Toma, G., Hult, M. and Keillor, B. D. (2005), emoving the Contextual Lens: A Multinational, Mult-setting Comparison of Service Evaluation Models, Journal of Retailing, 81(3), pp. 215-230] study suggestion that future research in service evaluations should focus on emerging service economies such as China. The intent of the research was to examine the suitability of the models suggested by Brady and colleagues in the Chinese market. The replication somewhat successfully duplicated their finding as to the superiority of the comprehensive service evaluation model. Additionally, we also sought to examine as to whether the service evaluation model is gender invariant. Our findings indicate that there are significant differences between gender. These findings are discussed relative to the limitations associated with the study.

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In this paper, we examine how brand ownership status affects consumers’ evaluation of brand extensions, using an experiment. In evaluating both brand extension and parent brands, brand owners differ from both nonowners and nonusers of a brand's product category in important ways. While the functional similarity between a brand and its extension impacts on all three groups’ brand extensions, its effects on nonowners and nonusers are more significant than those on brand owners. For brand owners, the most important consideration in their evaluation of brand extensions seems to be the image consistency between a brand and its extensions. Furthermore, there is an interaction effect between brand image consistency and product similarity for brand owners, whereas this effect is nonexistent for nonowners and nonusers.

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Self-identity as a careful pedestrian has not been fully considered in previous work on predicting intention to cross the road, or actual crossing behaviour, in non-optimal situations. Evidence suggests that self-identity may be a better predictor than attitudes in situations where decision-making styles have become habitual ways to respond. This study compared contributions of self-identity and attitudes to the prediction of intentions in two situations differing in level of habitual crossing expectation, and to crossing behaviour. Three hundred and sixty-two adults (17–92 years) completed a questionnaire measuring self-identity, attitudes, intentions, experience, social identity variables (e.g. age, gender) and personal limitations (mobility). Two hundred and five participants also completed a road-crossing simulation. Self-identity and attitude were both shown as significant independent predictors of intention in both situations. However, self-identity was less effective as a predictor in the higher risk scenario, where intention to perform the behaviour was lower, and for participants aged >75 years who had lower intention across scenarios. Self-identity strongly predicted intention to cross, which in turn predicted behaviour, but self-identity did not directly predict behaviour. Self-identity was strongly predicted by age. Implications for theories of compensation in older age and for design and targeting of pedestrian safety education are discussed.

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Adult pedestrian accident data has demonstrated that the risk of being killed or seriously injured varies with age and gender. A range of factors affecting road crossing choices of 218 adults aged 17-90+ were examined in a simulation study using filmed real traffic. With increasing age, women were shown to make more unsafe crossing decisions, to leave small safety margins and to become poorer at estimating their walking speed. However, the age effects on all of these were ameliorated by driving experience. Men differed from women in that age was not a major factor in predicting unsafe crossing decisions. Rather, reduced mobility was the key factor, leading them to make more unsafe crossings and delay longer in leaving the kerb. For men, driving experience did not predict unsafe road crossing decisions. Although male drivers were more likely to look both ways before crossing than male non-drivers, the impact of being a driver had a negative effect in terms of smaller safety margins and delay in leaving the kerb. The implications of the different predictor variables for men and women for unsafe road crossing are discussed and possible reasons for the differences explored.

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Shopping behavior is often exclusively studied through consumer purchases, since they are an easily measurable ouput. Still, the observation of in-store physical behavior (paths, moves and actions) is crucial, as is the quantification of its impact on purchases. Using an innovative PDA tool to precisely record and time stamp consumer’s moves and gestures, we extend the classical Market Basket Analysis (MBA) by integrating this new kind of information. We draw associations not only from purchases but also from in-store consumer moves and actions. We compare results of our new method with classical MBA results and show a significant improvement.

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Shopping behavior is often exclusively studied through consumer purchases, since they are an easily measurable ouput. Still, the observation of in-store physical behavior (path, moves and actions) is crucial, as is the quantification of its impact on purchases. Using an innovative PDA tool to precisely record and time stamp consumers' moves and actions, we extend the classical Market Basket Analysis (MBA) by integrating this new information: associations between product categories are measured not only from purchases but also from consumer physical behavior. We compare results of our new method with classical MBA results and show a significant improvement.

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The research described in this study replicates and extends the Brady et al., [Brady, M. K., Knight, G. A., Cronin Jr. J. Toma, G., Hult, M. and Keillor, B. D. (2005), emoving the Contextual Lens: A Multinational, Mult-setting Comparison of Service Evaluation Models, Journal of Retailing, 81(3), pp. 215-230] study suggestion that future research in service evaluations should focus on emerging service economies such as China. The intent of the research was to examine the suitability of the models suggested by Brady and colleagues in the Chinese market. The replication somewhat successfully duplicated their finding as to the superiority of the comprehensive service evaluation model. Additionally, we also sought to examine as to whether the service evaluation model is gender invariant. Our findings indicate that there are significant differences between gender. These findings are discussed relative to the limitations associated with the study.

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Sustained driving in older age has implications for quality of life and mental health. Studies have shown that despite the recognised importance of driving in maintaining health and social engagement, many women give up driving prematurely or adopt self-imposed restrictive driving practices. Emotional responses to driving have been implicated in these decisions. This research examined the effect of risk perception and feelings of vulnerability on women’s driving behaviour across the lifespan. It also developed and tested a modified theory of planned behaviour intervention to positively affect driving habits. The first two studies (N=395) used quantitative analysis to model driving behaviours affected by risk perception and feelings of vulnerability, and established that feelings of vulnerability do indeed affect women’s driving behaviour, specifically resulting in increases in driving avoidance and the adoption of maladaptive driving styles. Further, that self-regulation, conceptualised as avoidance, is used by drivers across the lifespan. Qualitative analysis of focus group data (N=48) in the third study provided a deeper understanding of the variations in coping behaviours adopted by sub-groups of drivers and extended the definition of self-regulation to incorporate adaptive coping strategies. The next study (N=64) reported the construction and preliminary validation of the novel self-regulation index (SRI) to measure wider self-regulation behaviours using an objective measure of driving behaviour, a simulated driving task. The understanding gained from the formative research was used in the final study, an extended theory of planned behaviour intervention to promote wider self-regulation behaviour, measured using the previously validated self-regulation index. The intervention achieved moderate success with changes in affective attitude and normative beliefs as well as self-reported behaviour. The results offer promise for self-regulation, incorporating a spectrum of planning and coping behaviours, to be used as a mechanism to assist drivers in achieving their personal mobility goals whilst promoting safe driving.

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Previous work has demonstrated that planning behaviours may be more adaptive than avoidance strategies in driving self-regulation, but ways of encouraging planning have not been investigated. The efficacy of an extended theory of planned behaviour (TPB) plus implementation intention based intervention to promote planning self-regulation in drivers across the lifespan was tested. An age stratified group of participants (N=81, aged 18-83 years) was randomly assigned to an experimental or control condition. The intervention prompted specific goal setting with action planning and barrier identification. Goal setting was carried out using an agreed behavioural contract. Baseline and follow-up measures of TPB variables, self-reported, driving self-regulation behaviours (avoidance and planning) and mobility goal achievements were collected using postal questionnaires. Like many previous efforts to change planned behaviour by changing its predictors using models of planned behaviour such as the TPB, results showed that the intervention did not significantly change any of the model components. However, more than 90% of participants achieved their primary driving goal, and self-regulation planning as measured on a self-regulation inventory was marginally improved. The study demonstrates the role of pre-decisional, or motivational components as contrasted with post-decisional goal enactment, and offers promise for the role of self-regulation planning and implementation intentions in assisting drivers in achieving their mobility goals and promoting safer driving across the lifespan, even in the context of unchanging beliefs such as perceived risk or driver anxiety.