Search With Learning for Differentiated Products: Evidence from E-Commerce

This article provides a method to estimate search costs in a differentiated product environment in which consumers are uncertain about the utility distribution. Consumers learn about the utility distribution by Bayesian updating their Dirichlet process prior beliefs. The model provides expressions for bounds on the search costs that can rationalize observed search and purchasing behavior. Using individual-specific data on web browsing and purchasing behavior for MP3 players sold online we show how to use these bounds to estimate search costs as well as the parameters of the utility distribution. Our estimates indicate that search costs are sizable. We show that ignoring consumer learning while searching can lead to severely biased search cost and elasticity estimates.     

Ergonomic risks in mining companies: a study in Paraiba/Brazil

The growing concern for the welfare of workers in the work environment, the importance of widespread use of ergonomics in the different sectors of industry. Yet most corporate practices that work with rudimentary or great need for human handling of materials is not fully in line with the ergonomic aspects. Given this, this article aims to identify ergonomic hazards in mining to later propose improvements in the process. After a series conducted plant visits, found that workers are exposed to various ergonomic risks, which entails the need for new healthy practices in the workplace. Finally, a series of proposals are submitted in order to avoid possible occupational diseases.     

Development of an ergonomics device for maintenance of hydraulic generators of Tucuruí hydropower plant

This paper aims to present an ergonomic device to assist in the maintenance of the units of Tucuruí Hydropower Plant. The development of this ergonomic device made possible to reduce maintenance time, reduce losses caused by billing, improve performance and reduce the physical strain for labors during the execution of services.     

Instruments of trainers' activity: the use of refentials in processes of recognition and validation of prior learning

In Portugal, recognition and validation of prior learning has emerged as an important training practice. Since 2001, it has been possible to obtain an academic certification by valuing learning, regardless of its origin. The current study was conducted with trainers and adults who were involved in processes of recognition, validation and certification of competences (RVCC). This research study, using qualitative research methods, described and tried to develop the comprehension of the use of referentials as instruments of trainers' activity. This analysis focused especially on three aspects: (i) the organization and development of RVCC processes; (ii) trainers' role in these processes; and (iii) the use of a referential as an instrument of activity. The findings suggested that the referential used in these processes mediates trainers' activity, functioning as competences identification guides. After an initial appropriation, trainers reconceptualize the referential by creating their own grids. There is clear variability in the use of this guiding document. Trainers revealed ambivalence towards the autonomy that they have in their work activity. Although they assess the opportunity to individually and freely create their work instruments in a positive way, they also lack a collective support and validation.     

Minor psychiatric disorders among nursing workers--is there an association with current or former night work?

We aimed at analyzing whether Minor Psychiatric Disorders (MPD) is associated to night work either currently or in the past. A cross-sectional study was conducted at three public hospitals in Brazil, with female nursing workers. Data collection (N=1,134) was based on a comprehensive questionnaire that included the self-reported questionnaire (SRQ-20) for screening of MPD. Former night workers were subdivided into three groups according to their reasons for leaving night work: (i) directly related to work, (ii) related to better reconcile with studies or another job, and (iii) related to health, sleep, fatigue or stress. Binomial logistic regression was performed, with adjustment for potential confounders. A dose response gradient was observed between current night work and MPD (OR=1.5; 95% CI: 1.1-2.2 and OR=2.1; 95%CI: 1.5-3.1 for those who worked up to five nights and six or more nights per 2-week span, respectively). Potential detrimental effects of night work were confirmed. The association between working at night and MPD was not restricted to current night workers as workers who left night work for health/fatigue/sleep/strain also showed higher chances of reporting MPD (OR=1.8;95%CI:1.14-2.90). Results contribute to the scientific debate on the impact of night work on health and wellbeing.     

Ergonomic sustainability based on the ergonomic maturity level measurement

This paper aims at the application of an ergonomic maturity model (EMM), in order to assess the ergonomic sustainability outreach of ergonomic actions. This proposition was motivated by the widespread sensation that the development of the discipline, its educational devices and related practices depends on the attitude of ergonomics practitioners rather than environmental macroergonomic conditions. Maturity modeling in this paper is undertaken as a tool for ergonomic practitioners. Thus, its foundations were uprooted from diverse fields: Clinic Psychology, Quality Management and Project Management. The paper brings about a detailled explanation of this ergonomic maturity tool. The empirical part is fulfilled by the examination - using the EMM - of four emblematic cases excerpted from our research lab ergonomic portfolio.     

DMAICR in an ergonomic risks analysis

The DMAICR problem-solving methodology is used throughout this paper to show you how to implement ergonomics recommendations. The DMAICR method consists of the following five six steps by which you can solve ergonomic design problems: The steps of the proposed method, adapting DMAICR, are the following: In the steep D, there is the definition of the project or the situation to be assessed and its guiding objectives, known as demand. In the step M, it relates to the work, tasks and organizational protocols and also includes the need of measuring. In the step A, all concepts are about the analysis itself. The step I is the moment of improving or incrementing. In the step C, control, prevention from prospective troublesome situation and implementation of management are the activities controlling the situation. R is Report. Some relevant technical and conceptual aspects for the comparison of these methodologies are illustrated in this paper. The steps of DMAICR were taken by a multifunctional team (multi-professional and multi-disciplinary) termed as focus group, composed by selected members of the company and supported by experts in ergonomics.     

Indirect Inference for Lévy‐driven continuous‐time GARCH models

We advocate the use of an Indirect Inference method to estimate the parameter of a COGARCH(1,1) process for equally spaced observations. This requires that the true model can be simulated and a reasonable estimation method for an approximate auxiliary model. We follow previous approaches and use linear projections leading to an auxiliary autoregressive model for the squared COGARCH returns. The asymptotic theory of the Indirect Inference estimator relies on a uniform strong law of large numbers and asymptotic normality of the parameter estimates of the auxiliary model, which require continuity and differentiability of the COGARCH process with respect to its parameter and which we prove via Kolmogorov's continuity criterion. This leads to consistent and asymptotically normal Indirect Inference estimates under moment conditions on the driving Lévy process. A simulation study shows that the method yields a substantial finite sample bias reduction compared with previous estimators.