Co-variation in time between near-far accommodation of the lens and trapezius muscle activity

Visual strain and discomfort may contribute to the generation of work-related musculoskeletal disorders among e.g. computer workers. A positive correlation on a group level between eye-lens accommodation and trapezius muscle activity has been reported. In this study we investigated the possibility of a direct, fast, connection between lens accommodation and trapezius muscles activity. The subjects focused alternately on Near and Far targets, with a mean switch time of 5 s, through four different lenses. The cross-correlation, R(tau) was computed, between the time signals of accommodation and electromyography (EMG) from 23 subjects. In the overall mean R(tau) of 736 curves, a small but significant correlation peak (0.019) with a delay (of the EMG signal) of about 0.3 s, revealed a small common component in the two signals. Among the lenses, the positive lens (3.5 D), showed the highest correlation peak (0.040). The correlation may be caused by a direct "hard-wired" connection between the ciliary and trapezius muscles. But it could also be caused indirectly by the subject's need for a more stable head in a more demanding visual task. The latter is supported by the result that the correlation was the highest in the positive lens condition. The present correlation is however weak and it has probably a low practical importance.     

Charisma as signal: An evolutionary perspective on charismatic leadership

We present an evolutionary perspective on charismatic leadership, arguing that charisma has evolved as a credible signal of a person's ability to solve a coordination challenge requiring urgent collective action from group members. We suggest that a better understanding of charisma's evolutionary and biological origins and functions can provide a broader perspective in which to situate current debates surrounding the utility and validity of charismatic leadership as a construct in the social sciences. We outline several key challenges which have shaped our followership psychology, and argue that the benefits of successful coordination in ancestral environments has led to the evolution of context-dependent psychological mechanisms which are especially attuned to cues and signals of outstanding personal leadership qualities. We elaborate on several implications of this signaling hypothesis of charismatic leadership, including opportunities for deception (dishonest signaling) and for large-scale coordination.     

Balanced consistency and balanced cost reduction for sequencing problems

We investigate the implications of balanced consistency and balanced cost reduction in the context of sequencing problems. Balanced consistency requires that the effect on the payoff from the departure of one agent to another agent should be equal between any two agents. On the other hand, balanced cost reduction requires that if one agent leaves a problem, then the total payoffs of the remaining agents should be affected by the amount previously assigned to the leaving agent. We show that the minimal transfer rule is the only rule satisfying efficiency and Pareto indifference together with either one of our two main axioms, balanced consistency and balanced cost reduction.     

Eye- and neck/shoulder-discomfort during visually demanding experimental near work

Frequent use of digital information technology has an impact on eye- and neck/shoulder-discomfort. Studies with cross sectional and intervention design indicate an association between the two symptom categories. Still, whether visually demanding near work, per se, contributes to increased neck/shoulder discomfort remains a question of debate. The aim of this laboratory study was to assess if visually demanding experimental near work affects eye- and neck/shoulder-discomfort when the posture was adjusted for comfort and no movements were allowed. Thirty-three healthy subjects performed a visually demanding computer screen task (viewing task) under four different optical lens conditions: binocular -3.5 D and monocular -3.5 D, +3.5 D and ± 0 D. During the experiment subjects were seated in an office chair (with neck support) that was individually adjusted for comfort. At baseline and after each viewing task, subjects reported their perceived eye- and neck/shoulder discomfort on Borg's CR-10 scale. Results show a significant increase of eye discomfort between baseline and the first viewing task, and a significant increase in neck/shoulder discomfort from baseline throughout the first three viewing tasks. Further analysis is required to determent whether the neck/shoulder discomfort was induced by the demanding near work or the static posture, or a combination.     

Walking in the shoes of others: Experimental testing of dual-interest and empathy in environmental choice

This paper further tests dual interest theory and the metaeconomics approach to environmental choice, recognizing a possible role for empathy–sympathy (the basis for an internalized, shared other-interest) in tempering and conditioning the more fundamental tendency to pursue self-interest. To test, we focus on rivers flowing through agricultural areas carrying sediments, chemicals, and fertilizers which are making their way into downstream rivers and lakes. We conduct a framed laboratory experiment modeling this problem: farmers decide on the usage of conservation technology to lessen impacts on the water quality (i.e. on the commons, the capacity to absorb these wastes) in downstream areas, which is more costly than the alternative intensive technology. The results confirm our hypotheses, demonstrating that Upstream Farmers who practice conservation are tempering profit maximization with empathy-based, environmentally conscious behavior. Such behavior better serves the farmers’ own-interest, and also helps Downstream Water Users. Environmental economics models need to explicitly include empathy–sympathy and the moral–ethical context it produces, providing a more scientific basis for conservation policy and programs.     

Dashed Hopes,Dashed Selves? A Sociometer Perspective on Self‐esteem Change Across the Transition to Secondary School

The transition from primary to secondary school challenges children's psychological well‐being. A cross‐transitional longitudinal study (N = 306; mean age = 12.2 years) examined why some children's self‐esteem decreases across the transition whereas other children's self‐esteem does not. Children's expected social acceptance in secondary school was measured before the transition; their actually perceived social acceptance was measured after the transition. Self‐esteem and Big Five personality traits were measured both pre‐ and posttransition. Self‐esteem changed as a function of the discrepancy between children's expected and actually perceived social acceptance. Furthermore, neuroticism magnified self‐esteem decreases when children's ‘hopes were dashed'—when they experienced disappointing levels of social acceptance. These findings provide longitudinal support for sociometer theory across the critical transition to secondary school.     

Species richness in urban parks and its drivers: A review of empirical evidence

There is growing recognition of urban areas as hosts for innovative ways to conserve and promote biodiversity. Parks, as one specific type of urban green space, constitute particularly important biodiversity hotspots in the cityscape. We reviewed empirical findings on the species richness in urban parks across all species groups that have been studied. The aim was to assess and discuss the overall species richness of urban parks, its community attributes and drivers. Search and subsequent selection process resulted in 62 papers from 25 different countries. For all examined species groups, the findings consistently show that parks are among the most species rich types of urban green spaces, but also that exotics constitute large shares, especially of plant species. Key ecological theories like the gradient approach and the island habitat ecological theory, and fundamental ecological relationships such as the species-area relationship are valid despite the manipulated ‘nature’ of parks and the surrounding urban matrix. Most studies surveyed large number of parks and applied ‘multi-scale’ approaches in tests of confounding variables, providing methodological strength. While matrix effects are consistently found to affect species richness negatively, the diversity of habitats and microhabitat heterogeneity contained in urban parks appears as the most decisive factor for the overall species richness. However, a constraint of research to date is the limitation of individual studies to one or a few species groups, rarely bridging between flora and fauna. Adopting ‘multi-species group’ approaches in future research is needed to further advance the understanding of the overall biodiversity of urban parks, and its drivers.     

Differences between paid and unpaid social services for beneficiaries

In many Western welfare states, social work services that have traditionally been provided by paid employees are being replaced by family support, community support, informal networks, and volunteering. For the field of social work, it is relevant to know what it matters to beneficiaries whether services are provided by volunteers or by paid employees. The central question of this article is therefore as follows: What are the differences between unpaid and paid social services for beneficiaries? The article is based on literature review and focus groups. Our results suggest that beneficiaries do experience some differences regarding the advantages of volunteer services for beneficiaries that can be summarized in three propositions: (1) services provided by volunteers are more relational than are services provided by paid employees, and they are therefore perceived as more equal, flexible and sincere. (2) The effects of volunteer services for beneficiaries are not exclusively positive. (3) Although particular tasks may appear to be interchangeable to some extent, the relative advantages of a given task depend upon whether it is performed by a paid worker or by a volunteer. Additional research is needed in order to provide further validation.     

Market hours,household work,child care,and wage rates of partners: an empirical analysis

The aim of this paper is to provide new evidence on the effect of partners’ wages on partners’ allocation of time. Earlier studies concluded that wage rates are an important determinant of partners’ hours of market and non-market work and also that house work may lower married women’s wage rates. However, the bulk of earlier literature in this area failed to account for the endogeneity of wages or the simultaneity of partners’ time allocation choices. Here we take a reduced form approach and specify a ten simultaneous equations model of wage rates, employment and hours of market work, house work and childcare of parents. Non-participants are included in the model. We exploit a rich time use dataset for France to estimate the model. We find that the own wage affects positively own market hours and negatively own house work and childcare hours. The wage of the father has a significantly negative effect on the mother’s market hours while her wage rate has a significantly positive effect on his house work hours.     

Expatriate contact with a local host: an intervention to increase social support

Social capital is a crucial factor for expatriates to employ as they cope with the demands of an international assignment. This longitudinal study used a mixed method approach to examine the social support benefits of expatriate contact with a local host. Western expatriates in the Netherlands were randomly divided into two groups: an experimental group (n = 33), that had contact with a Dutch host during 9 months, and a control group (n = 32) with no host. Qualitative methods such as interviews and diaries were included to shed light on the various types of social support that occurred. Results show that local hosts offered all four types of social support: social companionship, informational support, emotional support, and instrumental support. Furthermore, expatriates with a host increased their social capital; they received significantly more social support from host nationals than did those without a host. This study shows that HRD professionals may develop the social capital of expatriates by bringing them into contact with a local host, which can produce more social support from host nationals. Increased social capital may lead to a higher performance at both the individual and organisational levels.