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.     

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.     

Comparing swimsuits in 3D

In competitive swimming, suits have become more important. These suits influence friction, pressure and wave drag. Friction drag is related to the surface properties whereas both pressure and wave drag are greatly influenced by body shape. To find a relationship between the body shape and the drag, the anthropometry of several world class female swimmers wearing different suits was accurately defined using a 3D scanner and traditional measuring methods. The 3D scans delivered more detailed information about the body shape. On the same day the swimmers did performance tests in the water with the tested suits. Afterwards the result of the performance tests and the differences found in body shape was analyzed to determine the deformation caused by a swimsuit and its effect on the swimming performance. Although the amount of data is limited because of the few test subjects, there is an indication that the deformation of the body influences the swimming performance.     

Predicting long-term absenteeism from work in construction industry: a longitudinal study

In this study we examine whether the Work Ability Index (WAI) has additional value in predicting long-term absenteeism in construction industry. Results of the study show that the WAI has additional value in predicting absenteeism, but that the amount of explained variance is low. This is partly due to the definition of absenteeism in The Netherlands, where this study took place.     

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.     

Citizenship Norms in Eastern Europe

Research on Eastern Europe stresses the weakness of its civil society and the lack of political and social involvement, neglecting the question: What do people themselves think it means to be a good citizen? This study looks at citizens’ definitions of good citizenship in Poland, Slovenia, the Czech Republic and Hungary, using 2002 European Social Survey data. We investigate mean levels of civic mindedness in these countries and perform regression analyses to investigate whether factors traditionally associated with civic and political participation are also correlated with citizenship norms across Eastern Europe. We show that mean levels of civic mindedness differ significantly across the four Eastern European countries. We find some support for theories on civic and political participation when explaining norms of citizenship, but also demonstrate that individual-level characteristics are differently related to citizenship norms across the countries of our study. Hence, our findings show that Eastern Europe is not a monolithic and homogeneous bloc, underscoring the importance of taking the specificities of countries into account.     

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.     

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.     

From Source to Evidence? Teachers' Use of Historical Sources in Their Classrooms

To explore questions in history and to construct historical narratives, historians work with evidence from the past. This approach to teaching history (inquiry involving the use of evidence) is an accepted part of the research on history teaching and is promoted widely in standards frameworks and practitioner publications as “good history instruction.” What happens in a standards-based setting where teachers are covering large bodies of content? Do teachers use sources as part of their daily instruction? If so, how? We were afforded the unique opportunity to spend time observing what 35 teachers do by analyzing 352 videos submitted over a 4-year time span. We observed a spectrum of source use within and across teacher practice. In this article we share what we noticed.     

Do Reports of Age and Circumstances of First Intercourse Differ in a Birth Cohort When Asked Seventeen Years Apart?

Conclusions about temporal changes in age and circumstances of first intercourse are generally derived from retrospective reports by people of various ages in cross-sectional studies, with an inherent assumption of no bias stemming from time since the event. We examined this assumption through repeated questions on age and circumstances of first heterosexual intercourse (FHI) at ages 21 and 38 in a birth cohort. Despite considerable movement in individual reports, there was no bias in reported age of FHI. However, a greater proportion of both men and women stated at the later assessment both partners had been equally willing (versus persuading or persuaded). The distribution of current views of the appropriateness of the timing did not differ markedly between assessments, although there were many individual changes. Reports of contraceptive usage were similar at the two assessments for men but differed among women, mainly through more reporting that they could not remember. These findings imply that among cohorts born in the 1970s, there is no bias in reports of age of FHI many years after the event, and views on the appropriateness of timing persist. However, time biases reports in favor of a more mutual willingness.