Ambient light levels influence visual system size in birds and primates. Here, we argue that the same is true for humans. Light levels, in terms of both the amount of light hitting the Earth's surface and day length, decrease with increasing latitude. We demonstrate a significant positive relationship between absolute latitude and human orbital volume, an index of eyeball size. Owing to tight s...

OBJECTIVE This study sought to examine the influence of protective work factors on long-term sickness absence among employees reporting different levels of depressive symptoms in a representative sample of the Danish workforce. METHODS Questionnaire data were collected from a random sample of members of the Danish workforce aged between 18 and 64 years using information from two surveys with ...

The aim of this study was to compare the sensitometric properties of Insight and Ektaspeed Plus radiographic films manually and automatically processed using fresh and depleted chemical solutions. Ten sets of each type of film were obtained (1 set = 5 films), 5 sets being manually processed and 5 sets being automatically processed. A total of 100 films (50 Ektaspeed Plus and 50 Insight film) we...

*Department of Ecology and Evolutionary Biology, University of Michigan Herbarium, 3600 Varsity Drive, Ann Arbor, Michigan 48108-2287, U.S.A.; yDepartment of Botany, California Academy of Sciences, Golden Gate Park, San Francisco, California 94118, U.S.A.; zFlorida Museum of Natural History, Dickinson Hall, University of Florida, Gainesville, Florida 32611, U.S.A.; and §Arnold Arboretum, Harvar...

Determining longitude is incredibly difficult--for humans. Are animals fooling us into thinking that they have bicoordinate maps? New experiments show that at least some creatures effortlessly solve the seemingly insoluble problem of longitude.

3 images, we show that the auroral emission events that 4 initiate equatorward of the isotropic boundary (IB) ob-5 tained from a time-dependent empirical model, have sys-6 tematically steeper power-law slopes of energy, power, 7 area and lifetime probability distributions compared to 8 the events that initiate poleward of the IB. The low-9 latitude group of events contains a distinct subpopulat...

Simultaneous observations are valuable in providing further insights into the character of the quasi 2-day wave. In this study we investigate the period and amplitude for the quasi 2-day wave near 91 km using MF radars at London and Saskatoon, Canada, and in addition look at possible values of the zonal wave number. The results of the present study bring out certain new aspects of the quasi 2-d...