The winter day as a constraint for human activity in Western Europe
  Time use surveys in Denmark, Spain, France, Ireland, Italy and United Kingdom are analyzed to provide start, noon and end times for the main activities of a society: labor (the focus of this preprint), sleeping and eating. Also, the location at home is analyzed. Local times are converted into mean solar times and compared to latitude. Observed trends allow to unveil the winter day as a restriction for the human activity. Alternatively, apparently large time differences set forth by clocks, becomes smaller when observed as a time distance to winter sunrise or sunset. 
Jos\'e-Mar\'ia Mart\'in-Olalla
physics.soc-ph