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Author (up) Dacke, M.; Byrne, M.J.; Baird, E.; Scholtz, C.H.; Warrant, E.J. url  doi
openurl 
  Title How dim is dim? Precision of the celestial compass in moonlight and sunlight Type Journal Article
  Year 2011 Publication Philosophical Transactions of the Royal Society of London. Series B, Biological Sciences Abbreviated Journal Philos Trans R Soc Lond B Biol Sci  
  Volume 366 Issue 1565 Pages 697-702  
  Keywords Animals; Beetles/*physiology; Behavior, Animal; *Moon; *Sunlight; Video Recording  
  Abstract Prominent in the sky, but not visible to humans, is a pattern of polarized skylight formed around both the Sun and the Moon. Dung beetles are, at present, the only animal group known to use the much dimmer polarization pattern formed around the Moon as a compass cue for maintaining travel direction. However, the Moon is not visible every night and the intensity of the celestial polarization pattern gradually declines as the Moon wanes. Therefore, for nocturnal orientation on all moonlit nights, the absolute sensitivity of the dung beetle's polarization detector may limit the precision of this behaviour. To test this, we studied the straight-line foraging behaviour of the nocturnal ball-rolling dung beetle Scarabaeus satyrus to establish when the Moon is too dim--and the polarization pattern too weak--to provide a reliable cue for orientation. Our results show that celestial orientation is as accurate during crescent Moon as it is during full Moon. Moreover, this orientation accuracy is equal to that measured for diurnal species that orient under the 100 million times brighter polarization pattern formed around the Sun. This indicates that, in nocturnal species, the sensitivity of the optical polarization compass can be greatly increased without any loss of precision.  
  Address Department of Biology, University of Lund, Helgonavagen 3, 223 62 Lund, Sweden. marie.dacke@cob.lu.se  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0962-8436 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:21282173; PMCID:PMC3049003 Approved no  
  Call Number IDA @ john @ Serial 34  
Permanent link to this record
 

 
Author (up) Hansen, J.; Lassen, C.F. url  doi
openurl 
  Title Nested case-control study of night shift work and breast cancer risk among women in the Danish military Type Journal Article
  Year 2012 Publication Occupational and Environmental Medicine Abbreviated Journal Occup Environ Med  
  Volume 69 Issue 8 Pages 551-556  
  Keywords Adult; Aged; Aged, 80 and over; Breast Neoplasms/*etiology; Case-Control Studies; *Circadian Rhythm; Denmark/epidemiology; Female; Humans; Logistic Models; Middle Aged; Military Personnel; *Occupations; Odds Ratio; Risk Factors; *Sunlight; *Work; *Work Schedule Tolerance; oncogenesis  
  Abstract OBJECTIVES: Growing but limited evidence suggests that night shift work is associated with breast cancer. The authors conducted a nationwide case-control study nested within a cohort of 18,551 female military employees born in 1929-1968 to investigate the risk for breast cancer after night shift work and to explore the role of leisure time sun exposure and diurnal preference. METHODS: The authors documented 218 cases of breast cancer (1990-2003) and selected 899 age-matched controls from the cohort by incidence density sampling. Information on shift work, sun exposure habits, diurnal preference and other potential confounders was obtained from a structured questionnaire. ORs were estimated by multivariate conditional logistic regression. RESULTS: Overall, the authors observed an adjusted OR of 1.4 (95% CI 0.9 to 2.1) among women with ever compared with never night shifts. The RR for breast cancer tended to increase with increasing number of years of night shift work (p=0.03) and with cumulative number of shifts (p=0.02),with a neutral risk for fewer than three night shifts per week. The OR for the group with the highest tertile of cumulative exposure was 2.3 (95% CI 1.2 to 4.6). The most pronounced effect of night shift work on breast cancer risk was observed in women with morning chronotype preference and intense night shifts (OR=3.9, 95% CI 1.6 to 9.5). Night shift workers tended to sunbathe more frequently than day workers. CONCLUSIONS: The results indicate that frequent night shift work increases the risk for breast cancer and suggest a higher risk with longer duration of intense night shifts. Women with morning preference who worked on night shifts tended to have a higher risk than those with evening preference.  
  Address Institute of Cancer Epidemiology, Danish Cancer Society, Strandboulevarden 49, Copenhagen DK2100, Denmark. johnni@cancer.dk  
  Corporate Author Thesis  
  Publisher Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1351-0711 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:22645325 Approved no  
  Call Number IDA @ john @ Serial 156  
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Author (up) Kantermann, T. url  doi
openurl 
  Title Circadian biology: sleep-styles shaped by light-styles Type Journal Article
  Year 2013 Publication Current Biology : CB Abbreviated Journal Curr Biol  
  Volume 23 Issue 16 Pages R689-90  
  Keywords Human Health; Circadian Clocks/*radiation effects; Female; Humans; *Lighting; Male; *Photoperiod; *Sunlight  
  Abstract Light and darkness are the main time cues synchronising all biological clocks to the external environment. This little understood evolutionary phenomenon is called circadian entrainment. A new study illuminates our understanding of how modern light- and lifestyles compromise circadian entrainment and impact our biological clocks.  
  Address Chronobiology – Centre for Behaviour and Neurosciences, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands. thomas@kantermann.de  
  Corporate Author Thesis  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0960-9822 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:23968925 Approved no  
  Call Number LoNNe @ christopher.kyba @ Serial 501  
Permanent link to this record
 

 
Author (up) Muheim, R.; Phillips, J.B.; Akesson, S. url  doi
openurl 
  Title Polarized light cues underlie compass calibration in migratory songbirds Type Journal Article
  Year 2006 Publication Science (New York, N.Y.) Abbreviated Journal Science  
  Volume 313 Issue 5788 Pages 837-839  
  Keywords Alaska; *Animal Migration; Animals; Calibration; Cues; *Flight, Animal; Geography; *Light; Magnetics; *Orientation; Seasons; Sparrows/*physiology; Sunlight  
  Abstract Migratory songbirds use the geomagnetic field, stars, the Sun, and polarized light patterns to determine their migratory direction. To prevent navigational errors, it is necessary to calibrate all of these compass systems to a common reference. We show that migratory Savannah sparrows use polarized light cues from the region of sky near the horizon to recalibrate the magnetic compass at both sunrise and sunset. We suggest that skylight polarization patterns are used to derive an absolute (i.e., geographic) directional system that provides the primary calibration reference for all of the compasses of migratory songbirds.  
  Address Department of Animal Ecology, Lund University, Ecology Building, SE-223 62 Lund, Sweden. rmuheim@vt.edu  
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  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0036-8075 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:16902138 Approved no  
  Call Number IDA @ john @ Serial 243  
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Author (up) Scheffler, T.; Kyba, C.C.M. url  openurl
  Title Measuring Social Jetlag in Twitter Data Type Conference Article
  Year 2016 Publication Proceedings of the Tenth International AAAI Conference on Web and Social Media (ICWSM 2016) Abbreviated Journal  
  Volume Issue Pages 675-678  
  Keywords Human Health; Sunlight; Society  
  Abstract Social constraints have replaced the natural cycle of light and darkness as the main determinant of wake-up and activity times for many people. In this paper we show how Twitter activity can be used as a source of large-scale, naturally occurring data for the study of circadian rhythm in humans. Our year-long initial study is based on almost 1.5 million observations by over 200,000 users. The progression of the onset of Twitter activity times on free days in the course of the year is consistent with previous survey-based research on wake

times. We show that the difference in wake-up time (implicating lack of sleep) on weekdays compared to Sundays is between 1 hour and over 2 hours depending on the time of year. The data also supports the assertion that Daylight Saving Time greatly disrupts the easing of social jetlag in the Spring transition.
 
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  Area Expedition Conference ICWSM 2016  
  Notes Approved no  
  Call Number LoNNe @ kyba @ Serial 1453  
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