Approximation algorithms and hardness results for labeled connectivity problems

Let G=(V,E) be a connected multigraph, whose edges are associated with labels specified by an integer-valued function ℒ:E→ℕ. In addition, each label ℓ∈ℕ has a non-negative cost c(ℓ). The minimum label spanning tree problem (MinLST) asks to find a spanning tree in G that minimizes the overall cost of the labels used by its edges. Equivalently, we aim at finding a minimum cost subset of labels I⊆ℕ such that the edge set {e∈E:ℒ(e)∈I} forms a connected subgraph spanning all vertices. Similarly, in the minimum label s – t path problem (MinLP) the goal is to identify an s–t path minimizing the combined cost of its labels. The main contributions of this paper are improved approximation algorithms and hardness results for MinLST and MinLP.     

Wage dynamics and promotions inside and between firms

We focus on the dynamic relation between wage increases, promotions and job changes. In the empirical analyses, we use the Portuguese-matched employer–employee data Quadros de Pessoal. We find substantial wage returns to both promotions and job-to-job transitions. Our results are not consistent with models of full information and symmetric learning in a competitive and frictionless market. This might suggest that there is asymmetric information. An alternative explanation is that workers might search for a good match. Finally, we show that employer-reported promotions differ to a large extent from changes in hierarchical levels.     

Urbanization homogenizes the interactions of plant-frugivore bird networks

Urban Ecosystems - Anthropogenic activities are the main cause of habitat loss and fragmentation, which directly affects biodiversity. Disruption in landscape connectivity among populations may...     

Effect of Financial Inclusion on Poverty and Vulnerability to Poverty: Evidence Using a Multidimensional Measure of Financial Inclusion

This study examines the effect of financial inclusion on poverty and vulnerability to poverty of Ghanaian households. Using data extracted from the seventh round of the Ghana Living Standards Survey in 2016/17, a multiple correspondence analysis is employed to generate a financial inclusion index, and three-stage feasible least squares is used to estimate households’ vulnerability to poverty. Endogeneity associated with financial inclusion is resolved using distance to the nearest bank as an instrument in an instrumental variables probit technique. Results showed that while 23.4% of Ghanaians are considered poor, about 51% are vulnerable to poverty. We found that an increase in financial inclusion has two effects on household poverty. First, it is associated with a decline in a household’s likelihood of being poor by 27%. Second, it prevents a household’s exposure to future poverty by 28%. Female-headed households have a greater chance of experiencing a larger reduction in poverty and vulnerability to poverty through enhanced financial inclusion than do male-headed households. Furthermore, financial inclusion reduces poverty and vulnerability to poverty more in rural than in urban areas. Governments are encouraged to design or enhance policies that provide an enabling environment for the private sector to innovate and expand financial services to more distant places. Government investment in, and regulation of, the mobile money industry will be a necessary step to enhancing financial inclusion in developing countries.

     

Speak! Paradoxical Effects of a Managerial Culture of ‘Speaking Up’

We explore the intrinsic ambiguity of speaking up in a multinational healthcare subsidiary. A culture change initiative, emphasizing learning and agility through encouraging employees to speak up, gave rise to paradoxical effects. Some employees interpreted a managerial tool for improving effectiveness as an invitation to raise challenging points of difference rather than as something ‘beneficial for the organization’. We show that the process of introducing a culture that aims to encourage employees to speak up can produce tensions and contradictions that make various types of organizational paradoxes salient. Telling people to ‘speak up!’ may render paradoxical tensions salient and even foster a sense of low PsySafe.     

Participatory ergonomic intervention for prevention of low back pain: assembly line redesign case

This paper gives an overview of a participatory ergonomic intervention aimed at reducing low back pain cases in the dispatch department of a catalogue and e-commerce retail company. Based on the findings of the ergonomic analysis and design committee, the company's own employees redesigned the assembly line's layout. As a result of these changes two job tasks that involved manual material handling of boxes, identified by the revised NIOSH equation as posing an increased risk for lifting-related low back pain, were totally eliminated, and the employees responsible for moving boxes from the end of the assembly line to pallets on the ground were given more control over their jobs, and these jobs were also enriched with a new, less heavy task. These results demonstrate that participatory ergonomic interventions are a viable and effective strategy to reduce the exposure to work-related physical and psychosocial risk factors for low back pain.     

Association between repetitive work and occupational cold exposure

Occupational cold exposure is an important risk factor that increases stress at work and can induce many health effects like diseases and symptoms related to cold, including work-related musculoskeletal disorders. The methodological procedures were performed to measure these environmental variables as recommended by the ISO 7726/85. For the analysis of repetitiveness was used the OCRA checklist and evaluation of musculoskeletal morbidity conducted by the Nordic Musculoskeletal Questionnaire. So the objective of this study was to investigate the correlation between cold environmental variables and prevalence of musculoskeletal morbidity in the repetitive work. Was found association between work in cutting and boning sector (occupational cold and repetitive work) and the presence of musculoskeletal morbidity, with a significance of 99%.     

Identification of the mental workload of public employees in the administrative sector at a public university

In the workplace there are risk factors that can overwhelm the health of the worker causing physical and psychological disorders. Among these disorders, is occupational stress. Thus, this research proposes to measure the mental workload of job stress from the identification of demand, control and social support. It is an observational cross-sectional epidemiological character, performed with the Rectory office workers at the State University of West Paraná (Unioeste). Data collection was due to the application of the "Job Stress Scale" (JSS) and in its reduced version adapted to Portuguese. The survey sample consisted of 44 individuals. Statistical analysis was correlated inversely with medium intensity (r = -0.404) between age and social support. For males was found between control and age (r = 0.603). According to the data obtained, we conclude that most workers are exposed to passive work, leading to loss of skills or disinterest in the job. This study highlights the importance of research in the area and the need for new actions that change the conditions of stress at work.