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Author Dominoni, D.M.; Carmona-Wagner, E.O.; Hofmann, M.; Kranstauber, B.; Partecke, J.
Title Individual-based measurements of light intensity provide new insights into the effects of artificial light at night on daily rhythms of urban-dwelling songbirds Type Journal Article
Year (down) 2014 Publication Journal of Animal Ecology Abbreviated Journal J Anim Ecol
Volume 83 Issue 3 Pages 681–692
Keywords Animals; Biological rhythms; light at night; light loggers; light pollution; night shift; noise; radiotelemetry; sleep disruption; temporal niche; urban sprawl
Abstract Summary

The growing interest in the effects of light pollution on daily and seasonal cycles of animals has led to a boost of research in recent years. In birds, it has been hypothesized that artificial light at night can affect daily aspects of behaviour, but one caveat is the lack of knowledge about the light intensity that wild animals, such as birds, are exposed to during the night.

Organisms have naturally evolved daily rhythms to adapt to the 24-h cycle of day and night, thus, it is important to investigate the potential shifts in daily cycles due to global anthropogenic processes such as urbanization.

We captured adult male European blackbirds (Turdus merula) in one rural forest and two urban sites differing in the degree of anthropogenic disturbance. We tagged these birds with light loggers and simultaneously recorded changes in activity status (active/non-active) through an automated telemetry system. We first analysed the relationship between light at night, weather conditions and date with daily activity onset and end. We then compared activity, light at night exposure and noise levels between weekdays and weekends.

Onset of daily activity was significantly advanced in both urban sites compared to the rural population, while end of daily activity did not vary either among sites. Birds exposed to higher amounts of light in the late night showed earlier onset of activity in the morning, but light at night did not influence end of daily activity. Light exposure at night and onset/end of daily activity timing was not different between weekdays and weekends, but all noise variables were. A strong seasonal effect was detected in both urban and rural populations, such as birds tended to be active earlier in the morning and later in the evening (relative to civil twilight) in the early breeding season than at later stages.

Our results point at artificial light at night as a major driver of change in timing of daily activity. Future research should focus on the costs and benefits of altered daily rhythmicity in birds thriving in urban areas.
Address Department of Migration and Immuno-ecology, Max Planck Institute for Ornithology, Am Obstberg 1, 78315, Radolfzell, Germany; Department of Biology, University of Konstanz, Universitatsstrasse 10, 78464, Konstanz, Germany
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 0021-8790 ISBN Medium
Area Expedition Conference
Notes PMID:24102250 Approved no
Call Number LoNNe @ christopher.kyba @ Serial 375
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Author He, C.; Anand, S.T.; Ebell, M.H.; Vena, J.E.; Robb, S.W.
Title Circadian disrupting exposures and breast cancer risk: a meta-analysis Type Journal Article
Year (down) 2014 Publication International Archives of Occupational and Environmental Health Abbreviated Journal Int Arch Occup Environ Health
Volume 88 Issue 5 Pages 533-547
Keywords Human Health; Circadian disruption; Breast cancer; Meta-analysis; Oncogenesis; BrCA; shift work; meta-analysis
Abstract PURPOSE: Shift work, short sleep duration, employment as a flight attendant, and exposure to light at night, all potential causes of circadian disruption, have been inconsistently associated with breast cancer (BrCA) risk. The aim of this meta-analysis is to quantitatively evaluate the combined and independent effects of exposure to different sources of circadian disruption on BrCA risk in women. METHODS: Relevant studies published through January 2014 were identified by searching the PubMed database. The pooled relative risks (RRs) and corresponding 95 % confidence intervals (CIs) were estimated using fixed- or random effects models as indicated by heterogeneity tests. Generalized least squares trend test was used to assess dose-response relationships. RESULTS: A total of 28 studies, 15 on shift work, 7 on short sleep duration, 3 on flight attendants, and 6 on light at night were included in the analysis. The combined analysis suggested a significantly positive association between circadian disruption and BrCA risk (RR = 1.14; 95 % CI 1.08-1.21). Separate analyses showed that the RR for BrCA was 1.19 (95 % CI 1.08-1.32) for shift work, 1.120 (95 % CI 1.119-1.121) for exposure to light at night, 1.56 (95 % CI 1.10-2.21) for employment as a flight attendant, and 0.96 (95 % CI 0.86-1.06) for short sleep duration. A dose-response analysis showed that each 10-year increment of shift work was associated with 16 % higher risk of BrCA (95 % CI 1.06-1.27) based on selected case-control studies. No significant dose-response effects of exposure to light at night and sleep deficiency were found on BrCA risk. CONCLUSIONS: Our meta-analysis demonstrates that circadian disruption is associated with an increased BrCA risk in women. This association varied by specific sources of circadian disrupting exposures, and a dose-response relationship remains uncertain. Therefore, future rigorous prospective studies are needed to confirm these relationships.
Address Department of Epidemiology and Biostatistics, College of Public Health, University of Georgia, 101 Buck Road, Health Sciences Campus, B.S. Miller Hall, Athens, GA, 30602, USA, willahe@uga.edu
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 0340-0131 ISBN Medium
Area Expedition Conference
Notes PMID:25261318 Approved no
Call Number IDA @ john @ Serial 1064
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Author Bonmati-Carrion, M.; Arguelles-Prieto, R.; Martinez-Madrid, M.; Reiter, R.; Hardeland, R.; Rol, M.; Madrid, J.
Title Protecting the Melatonin Rhythm through Circadian Healthy Light Exposure Type Journal Article
Year (down) 2014 Publication International Journal of Molecular Sciences Abbreviated Journal IJMS
Volume 15 Issue 12 Pages 23448-23500
Keywords human health; chronodisruption; circadian; light at night (LAN); melanopsin; melatonin
Abstract Currently, in developed countries, nights are excessively illuminated (light at night), whereas daytime is mainly spent indoors, and thus people are exposed to much lower light intensities than under natural conditions. In spite of the positive impact of artificial light, we pay a price for the easy access to light during the night: disorganization of our circadian system or chronodisruption (CD), including perturbations in melatonin rhythm. Epidemiological studies show that CD is associated with an increased incidence of diabetes, obesity, heart disease, cognitive and affective impairment, premature aging and some types of cancer. Knowledge of retinal photoreceptors and the discovery of melanopsin in some ganglion cells demonstrate that light intensity, timing and spectrum must be considered to keep the biological clock properly entrained. Importantly, not all wavelengths of light are equally chronodisrupting. Blue light, which is particularly beneficial during the daytime, seems to be more disruptive at night, and induces the strongest melatonin inhibition. Nocturnal blue light exposure is currently increasing, due to the proliferation of energy-efficient lighting (LEDs) and electronic devices. Thus, the development of lighting systems that preserve the melatonin rhythm could reduce the health risks induced by chronodisruption. This review addresses the state of the art regarding the crosstalk between light and the circadian system.
Address Department of Physiology, Faculty of Biology, University of Murcia, Murcia 30100, Spain
Corporate Author Thesis
Publisher MDPI Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1422-0067 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 1078
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Author Fernandez, F.; Lu, D.; Ha, P.; Costacurta, P.; Chavez, R.; Heller, H.C.; Ruby, N.F.
Title Circadian rhythm. Dysrhythmia in the suprachiasmatic nucleus inhibits memory processing Type Journal Article
Year (down) 2014 Publication Science (New York, N.Y.) Abbreviated Journal Science
Volume 346 Issue 6211 Pages 854-857
Keywords Animals; circadian rhythm; circadian disruption; memory; suprachiasmatic nucleus; Biological Clocks; dysrhythmia; Siberian hamster; Phodopus sungorus; sleep
Abstract Chronic circadian dysfunction impairs declarative memory in humans but has little effect in common rodent models of arrhythmia caused by clock gene knockouts or surgical ablation of the suprachiasmatic nucleus (SCN). An important problem overlooked in these translational models is that human dysrhythmia occurs while SCN circuitry is genetically and neurologically intact. Siberian hamsters (Phodopus sungorus) are particularly well suited for translational studies because they can be made arrhythmic by a one-time photic treatment that severely impairs spatial and recognition memory. We found that once animals are made arrhythmic, subsequent SCN ablation completely rescues memory processing. These data suggest that the inhibitory effects of a malfunctioning SCN on cognition require preservation of circuitry between the SCN and downstream targets that are lost when these connections are severed.
Address Biology Department, Stanford University, Stanford CA, USA. ruby@stanford.edu
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 0036-8075 ISBN Medium
Area Expedition Conference
Notes PMID:25395537 Approved no
Call Number IDA @ john @ Serial 1069
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Author Hurley, S.; Nelson, D.O.; Garcia, E.; Gunier, R.; Hertz, A.; Reynolds, P.
Title A cross-sectional analysis of light at night, neighborhood sociodemographics and urinary 6-sulfatoxymelatonin concentrations: implications for the conduct of health studies Type Journal Article
Year (down) 2013 Publication International Journal of Health Geographics Abbreviated Journal Int J Health Geogr
Volume 12 Issue 1 Pages 39
Keywords circadian disruption; 6-sulftoxymelatonin; melatonin; aMT6s, DMSP; light at night
Abstract BACKGROUND: There is accumulating evidence that circadian disruption, mediated by alterations in melatonin levels, may play an etiologic role in a wide variety of diseases. The degree to which light-at-night (LAN) and other factors can alter melatonin levels is not well-documented. Our primary objective was to evaluate the degree to which estimates of outdoor environmental LAN predict 6-sulftoxymelatonin (aMT6s), the primary urinary metabolite of melatonin. We also evaluated other potential behavioral, sociodemographic, and anthropomorphic predictors of aMT6s. METHODS: Study participants consisted of 303 members of the California Teachers Study who provided a 24-hour urine specimen and completed a self-administered questionnaire in 2000. Urinary aMT6s was measured using the Buhlmann ELISA. Outdoor LAN levels were estimated from satellite imagery data obtained from the U.S. Defense Meteorological Satellite Program's (DMSP) Operational Linescan System and assigned to study participants' geocoded residential address. Information on other potential predictors of aMT6s was derived from self-administered surveys. Neighborhood socioeconomic status (SES) was based on U.S. Census block group data. RESULTS: Lower aMT6s levels were significantly associated with older age, shorter nights, and residential locations in lower SES neighborhoods. Outdoor sources of LAN estimated using low-dynamic range DMSP data had insufficient variability across urban neighborhoods to evaluate. While high-dynamic range DMSP offered much better variability, it was not significantly associated with urinary aMT6s. CONCLUSIONS: Future health studies should utilize the high-dynamic range DMSP data and should consider other potential sources of circadian disruption associated with living in lower SES neighborhoods.
Address
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 1476-072X ISBN Medium
Area Expedition Conference
Notes PMID:24127816; PMCID:PMC3766028 Approved no
Call Number IDA @ john @ Serial 142
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