Master Production Scheduling Under Rolling Planning Horizons with Fixed Order Intervals

Fixed interval scheduling is studied in the context of a rolling horizon framework that is developed by building on previous work in the master scheduling area. The rolling horizon framework includes a stationary scheduling model which uses the “time fencing’concept by partitioning the planning horizon into three sections. The lengths of these sections and the frequency at which the stationary problem is updated and resolved are discussed as parameters of the rolling horizon model. Two different interpretations of the freeze interval parameter are examined, enabling confirmation and clarification of results presented in an earlier study. Details are given for three methods of calculating safety stocks as a function of rolling horizon parameters, including a method which results in optimal safety stock levels. A comparison of the safety stock methods shows that the constant safety stock method can result in inventories that are significantly above optimal under certain conditions, whereas the constant service level method consistently yields nearly optimal results.     

Is a Picture Worth A Thousand Words? An Experiment Comparing Observer-Based Skin Tone Measures

Several different measures of skin color are popular in social science surveys, yet we have little evidence to suggest which method is the most valid or re     

Terms of engagement: Facebook and Twitter use among nonprofit human service organizations

This study uses Lovejoy and Saxton's (2012) hierarchy of engagement to analyze how nonprofit human service organizations use Facebook and Twitter to engage stakeholders. Their framework has not been applied to this nonprofit subgroup, and most previous scholarship on this topic focuses on just one platform. We also contribute by drawing on organizational theory to better understand variation in the modes of engagement organizations emphasize. Based on our analysis, we add new subcategories to the hierarchy of engagement. In addition, we find that compared to other nonprofit subgroups examined in previous research, the organizations in our sample placed a greater emphasis on using social media messages to ask stakeholders to take action. We report only modest variations in how organizations were using Facebook and Twitter. Finally, according to our results, resource dependence and stewardship theories help explain the modes of engagement organizations prioritize.     

Analysis on the relationship between the school furniture and the work surface lighting and the body posture of public Middle School students from João Pessoa, Paraíba, Brazil

The main objective of this study is to evaluate the impact of school furniture and work surface lighting on the body posture of two public Middle School students from Paraíba (Brazil). The target population included 8th grade groups involving 31 students. Brazilian standards for lighting levels, the CEBRACE standards for furniture measurements and the Postural Assessment Software (SAPO) for the postural misalignment assay were adopted for the measurements comparison. The statistic analysis includes analyses of parametric and non-parametric correlations. The results show that the students' most affected parts of the body were the spine, the regions of the knees and head and neck and about 90% of the students presented postural misalignment. The lighting levels were usually found below 300 lux, below recommended levels. Such results indicate the need of investments in more suitable school furniture and structural reforms aimed at improving the lighting in the classrooms, which could fulfill the students' profile and reduce their complaints.     

Job stress management protocol using a merge between cognitive-behavioral techniques and ergonomic tools

This paper presents a protocol for work distress assessment. Work distress is defined as a merge between nonergonomic related aspects, in tasks or environment, and adversely conditions perceived for a worker, in a certain work situation. This frame requires an approach that can treat individuals and organizational factors in the same way, at the same time. For this, we elaborate a psycho-ergonomics method, associating concepts and practices from cognitive-behavioral techniques and work ergonomic analysis, which we named CEWAT - Cognitive-Behavioral Work Analysis Technique. This paper presents CEWAT's foundations and structure, in steps. An application to a complex and dangerous system illustrates its benefits in the ergonomics action.     

Irregular working times and metabolic disorders among truck drivers: a review

A number of studies to better understand the complex physiological mechanism involved in regulating body weight have been conducted. More specifically, the hormones related to appetite, leptin and ghrelin, and their association to obesity have been a focus of investigation. Circadian patterns of these hormones are a new target of research. The behaviour of these hormones in individuals subject to atypical working times such as shiftwork remains unclear. Shiftwork is characterized by changes in biological rhythms and cumulative circadian phase changes, being associated with high rates of obesity and metabolic syndrome. Truck drivers, who work irregular shifts, frequently present a high prevalence of obesity, which might be associated with work-related factors and/or lifestyle. In this context, the aim of this paper was to discuss the relationship of body mass index, appetite-related hormones and sleep characteristics in truck drivers who work irregular shifts compared with day workers.     

Functional disability among chronic pain patients receiving long-term opioid treatment

This study of 2,163 adult chronic, non-cancer-pain, long-term opioid therapy patients examines the relationship of depression to functional disability by measuring average pain interference, activity limitation days, and employment status. Those with more depression symptoms compared to those with fewer were more likely to have worse disability on all 3 measures (average pain interference score >5, OR = 5.36, p < .0001; activity limitation days ≥ 30, OR = 4.05, p < .0001; unemployed due to health reasons, OR = 4.06, p < .0001). Depression might play a crucial role in the lives of these patients; identifying and treating depression symptoms in chronic pain patients should be a priority.     

Predicting the recipients of social work support,and its impact on emotional and behavioural problems in early childhood

This paper examines the recipients of social work support in the Millennium Cohort Study. Using panel analysis and fixed effects models, it investigates the factors that lead to the receipt of any type of social work support for individuals with young children and the effects of this support on changes in the prevalence of emotional and behavioural problems in these children. We find that divorce or separation, and episodes of homelessness are two important factors that lead to the receipt of social work support. Mothers with male children are also more likely to receive social work support. However, we find no clear evidence that social work support has any effect on changes in children's emotional and behavioural problems over time. The implications of these findings for social work research and for practice and policy are discussed.     

Who is a volunteer? A cultural and temporal exploration of volunteerism

This study’s purpose was to develop a temporal and cultural definition of volunteering in China. Using a comparative mixed-methods approach, N₁ = 218 Chinese students in Hong Kong were surveyed about their perceptions of volunteering. These quantitative data were compared cross-culturally with a sample of adults in the United States who used the same instrument called Who is a Volunteer? Subsequently, N₂ = 40 of these same students voluntarily participated in a series of focus groups, to further explore more in-depth their opinions about volunteering. The main quantitative results revealed that at the extreme ends of the volunteer scale, both the U.S. and Chinese samples could readily distinguish what volunteering was or was not. The more nuanced empirical differences on the scale (24% of the 21 items) were explained either by unique cultural differences, or the longer and more prominent history that volunteering has had in North America versus China. Main qualitative findings revealed additional between-group cultural differences exemplified by (1) a more family-centric and collectivist Chinese culture versus a more individualistic American culture, (2) a role blurring about volunteer activities versus paid work activities, and (3) that both organizational and cultural context must be seriously considered when defining volunteerism. This study adds to the growing definitional literature on this transformational concept and represents the largest comparative empirical investigation on this subject from East Asia.