A feasibility approach for constructing combinatorial designs of circulant type

In this work, we propose an optimization approach for constructing various classes of circulant combinatorial designs that can be defined in terms of autocorrelation. The problem is formulated as a so-called feasibility problem having three sets, to which the Douglas–Rachford projection algorithm is applied. The approach is illustrated on three different classes of circulant combinatorial designs: circulant weighing matrices, D-optimal matrices of circulant type, and Hadamard matrices with two circulant cores. Furthermore, we explicitly construct two new circulant weighing matrices, a CW(126, 64) and a CW(198, 100), whose existence was previously marked as unresolved in the most recent version of Strassler’s table.     

Schooling and Factors Affecting Decisions on Schooling by Household Members in the Rural Areas of Turkey

Despite the fact that rural education has always been one of the most important means of rural development, it has been ignored in many developing countries, with the result that rural development has not achieved great success. The problems of education in rural areas are not only related to the amount the country spends on education or to the system of education. The socio-economic condition of the individuals living in these areas and the form of rural education also play an important part. The present study deals with the socio-economic factors that influence the education level which is achieved. The assessments in the study are based on data gathered in a survey of 386 households carried out in the Aegean Region of Turkey. The work consists of three parts: the state of education in rural areas; the factors adversely affecting an individual’s decision to continue at school; and the employment situation of individuals who did not continue their education. In the results section, some suggestions have been made regarding the provision of employment opportunities to individuals who have not completed their education and who have had no job training.     

Implementation of Jefferson-d’Hondt rule in the formation of a parliamentary committee

Same parliaments, to form a committee of size $q$ , use a voting process like the following: every parliamentary member votes for one out of a fixed set of candidates, and those $q$ candidates receiving more votes are elected for the committee. Assuming total discipline of vote, this is a game form in which players are the parliamentary groups. We investigate, according to some natural hypotheses about preferences, the likely distribution of the members of this committee. The main results are: (a) when fractional votes are allowed, there is a complete agreement between the distribution among the groups of the elected candidates that are outcomes of a Nash equilibrium and the distribution that, according to the size of the groups, would compute the Jefferson-d’Hondt allocation rule, and (b) when fractional votes are not allowed, there is a near agreement for a majority of situations.     

The division problem with voluntary participation

The division problem consists of allocating a given amount of a homogeneous and perfectly divisible good among a group of agents with single-peaked preferences on the set of their potential shares. A rule proposes a vector of shares for each division problem. The literature has implicitly assumed that agents will find acceptable any share they are assigned to. In this article we consider the division problem when agents’ participation is voluntary. Each agent has an idiosyncratic interval of acceptable shares where his preferences are single-peaked. A rule has to propose to each agent either to not participate or an acceptable share because otherwise he would opt out and this would require to reassign some of the remaining agents’ shares. We study a subclass of efficient and consistent rules and characterize extensions of the uniform rule that deal explicitly with agents’ voluntary participation.     

Stress and musculoskeletal discomfort among hydrocarbon industry workers in Mexico

This study of 114 workers in the hydrocarbon industry was conducted to identify the relationship between stress and musculoskeletal discomfort, and to view the roles played by such factors as age, schooling, obesity, workplace and job seniority. All factors except seniority were found to affect the presence of musculoskeletal discomfort in some area of the body.     

Participatory ergonomics among female cashiers from a department store

The objective of this paper was to control ergonomic risks among female cashiers working in a department store belonging to the retail market. This study was conducted between May and November 2010. Participatory ergonomics was applied through knowing and understanding how the company works, establishing the work team (Ergo group), training the team in ergonomics-related topics, and making decisions and interventions. The sample was composed of 71 participants--mostly female cashiers--, and all of them have a musculoskeletal compromise, declaring pain or discomfort mainly in the neck, lower back, right wrist and shoulders. Among others, following problems were found: postural overload, repetitive work, manual load handling, mental fatigue, environmental discomfort, variable work schedules, extended working days, and absence of breaks. In the intervention, the main implemented changes were the redesign of workstation, complete change of chairs and keyboards, and the implementation of a rotation system, as well breaks for compensatory exercises. After that, an evident improvement of found problems was observed, therefore it can be concluded that participatory ergonomics is an attractive methodology, appropriate and efficient for solving and controlling ergonomic risks and problems.     

Nurses' working tasks and MSDs back symptoms: results from a national survey

Healthcare workers, namely registered nurses (RN), are frequently exposed to work-related musculoskeletal disorders (WRMSDs) risk factors. Identifying the symptoms of these disorders is one of the first epidemiological steps to managing them. This study aims to identify WRMSDs prevalence symptoms in Portuguese RN. During 8 months (2010-2011) the National Public Health School and the Portuguese Registered Nurses Board made a call to all RN to answer an online WRMSDs questionnaire. Respondents (n=2140) are mostly females (77.4%) and work mainly in hospitals (n=1396) and in primary healthcare centers (n=421). Results show high symptoms prevalence (last 12 months) in the lower back (60.6%), the upper back (44.5%), and the neck (48.6%). Nurses' activity, especially patient hygiene in bed, is a strong contributor (p>0.05) to pain in the upper back (OR=1.39 [1.09-1.80]) and lower back (OR=1.4 [1.08-1.84]). Patient holdup without mechanical support has the highest relationship (p>0.05) between work tasks and symptoms in the last 12 months in the upper back (OR=1.50 [1.19-1.90]). Prevalence rates of WRMSDs symptoms in Portuguese nurses are no different from other studies with Swedish, Italian and Greek nurses. Maybe changes in healthcare systems didn't change the way care is delivered and we must rethink how to prevent nurses WRMSDs.     

Ergonomic and individual risk evaluation

The ergonomic risks constitute a vital aspect of study and prevention for the worker's health, especially for people with different capacities. Very job has and implies certain type of risk for the worker's health, depending on the conditions it is done with the use of tools or without them. Aplicated techniques: posturogram, baropodometry, Schober test, biocinemátic chain test, Fukuda test, propioceptiva plataform in personnel with special capabilities.