Usability of car stereo

Automotive sound systems vary widely in terms of functions and way of use between different brands and models what can bring difficulties and lack of consistency to the user. This study aimed to analyze the usability of car stereo commonly found in the market. Four products were analyzed by task analysis and after use reports and the results indicate serious usability issues with respect to the form of operation, organization, clarity and quality of information, visibility and readability, among others.     

Examination of computer task exposures in radiologists: a work systems approach

Radiologists are intensive computer users as they review and interpret radiological examinations using the Picture Archiving and Communication Systems (PACS). Since their computer tasks require the prolonged use of pointing devices, a high prevalence of Musculoskeletal Disorders (MSDs) is reported. The first phase of this study involved conducting a Cognitive Work Analysis in conjunction with a Participatory Ergonomics approach to perform a total work system analysis. We also conducted an ergonomic survey as well as collected computer use data, specifically for the mouse and keyboard. The goal of the study was to reduce the physical exposures for radiologists. This paper presents Phase I results describing the analyses and redesign process of the radiologists tasks, training design, computer use, and selected survey results.     

Why without pay? Intrinsic motivation in the unpaid labour supply

Economic theory explains the supply of volunteering alternatively as an ordinary consumer good or an investment good. This paper provides a simultaneous approach, considering both objectives, by using the psychological distinction between intrinsic and extrinsic motivations, in order to reconcile conflicting results reported in the literature. Following the simultaneity approach, the paper develops a theoretical model of unpaid labour supply within an agent's two-period utility maximization problem, taking into account the role of psychological motivation. The theoretical hypotheses are tested with a sample selection model for Italy, by using the 1997 Multipurpose Households Survey on everyday life issues carried out by the Italian National Statistical Office. A robustness analysis and endogeneity test for intrinsic motivation are also performed. Empirical analysis rejects the hypothesis that only a consumption or investment motive can explain Italian volunteers’ behaviour, supporting the hypothesis that both motives interact in shaping regular unpaid labour supply, with a stronger impact of consumption motives. The relevant variables for frequently supplied unpaid labour are intrinsic motivation, age, household income, family responsibilities and activity sector.     

Joint projections of temperature and precipitation change from multiple climate models: a hierarchical Bayesian approach

Summary.  Posterior distributions for the joint projections of future temperature and precipitation trends and changes are derived by applying a Bayesian hierachical model to a rich data set of simulated climate from general circulation models. The simulations that are analysed here constitute the future projections on which the Intergovernmental Panel on Climate Change based its recent summary report on the future of our planet's climate, albeit without any sophisticated statistical handling of the data. Here we quantify the uncertainty that is represented by the variable results of the various models and their limited ability to represent the observed climate both at global and at regional scales. We do so in a Bayesian framework, by estimating posterior distributions of the climate change signals in terms of trends or differences between future and current periods, and we fully characterize the uncertain nature of a suite of other parameters, like biases, correlation terms and model-specific precisions. Besides presenting our results in terms of posterior distributions of the climate signals, we offer as an alternative representation of the uncertainties in climate change projections the use of the posterior predictive distribution of a new model's projections. The results from our analysis can find straightforward applications in impact studies, which necessitate not only best guesses but also a full representation of the uncertainty in climate change projections. For water resource and crop models, for example, it is vital to use joint projections of temperature and precipitation to represent the characteristics of future climate best, and our statistical analysis delivers just that.     

The emancipation of disability studies in Portugal

Despite the interest of the social sciences in issues of exclusion and inequality, the question of disability, as a key issue of reflection, remains absent from many academic areas. The emergence of disability studies owes much to contexts in which the activism of disabled people has revealed the structural conditions that oppress and neglect experiences of disability. Bearing in mind the specific features of the Portuguese socio-political environment, two lines of inquiry are developed in this text. Firstly, what are the challenges faced by Portuguese academics in making disability a central issue, enabling it to confront the silencing of the voices and experiences of disabled people in society? Secondly, how important is it for research to engage with an ethical and political paradigm that supports the rights of disabled people?     

Can skill-biased technological change compress unemployment rate differentials across education groups?

Our aim is to explain why the pattern of relative unemployment rates by education groups was non monotonic in most of the OECD countries. In a two-sector matching model, a simple unexpected productivity shock biased against unskilled labor can replicate the observed dynamics. Demographic effects of skill-biased shocks can be related to inequality in the distribution of wealth. Received: 27 April 1999/Accepted: 08 June 2000     

It Takes Two to Tango: Couples’ Happiness and Childbearing

The existing literature has so far considered the role of the individual’s subjective well-being on fertility, neglecting the importance of the partner’s well-being. Using data from the British Household Panel Survey (BHPS) and event history models estimated separately by parity, we find that in a couple, women’s happiness matters more than that of the male partner in terms of having the first child. Specifically, we observe that couples in which either partner is happier than usual are more at risk of having the first child, but the effect is stronger with higher happiness of the woman. For the transition to the second child, we find that couples in which the woman declares to be happier or less happy than usual have a lower risk of childbirth. We, moreover, find support for a multiplicative effect of partners’ SWB on the decision to have a first child. Our results show that failing to acknowledge that the subjective well-being of both partners matters for the inherently joint decision making of childbearing can lead to an incomplete view of how subjective well-being affects fertility.     

Motivation as a limit to pricing

A monetary reward offered by a principal tends to crowd out an agent's willingness to perform the task for its own sake (i.e. based on intrinsic motivation) if the agent's sense of recognition, fairness, or self-determination are thereby negatively affected. The crowding-out effect of pricing may also spill over into sectors where no pricing is applied (spillover effect) if the persons affected find it costly to dinstinguish their motivations according to sectors. Motivation crowding-out and spillover narrow the scope for successfully applying monetary rewards. These theoretical claims are supported by real-life observations for environmental policy and blood donations.