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Author Eriksen, A.; Wabakken, P. url  doi
openurl 
  Title (up) Activity patterns at the Arctic Circle: nocturnal eagle owls and interspecific interactions during continuous midsummer daylight Type Journal Article
  Year 2018 Publication Journal of Avian Biology Abbreviated Journal J Avian Biol  
  Volume 49 Issue 7 Pages e01781  
  Keywords Animals  
  Abstract Circadian rhythms result from adaptations to biotic and abiotic environmental conditions that cycle through the day, such as light, temperature, or temporal overlap between interacting species. At high latitudes, close to or beyond the polar circles, uninterrupted midsummer daylight may pose a challenge to the circadian rhythms of otherwise nocturnal species, such as eagle owls Bubo bubo. By non‐invasive field methods, we studied eagle owl activity in light of their interactions with their main prey the water vole Arvicola amphibius, and their competitor the white‐tailed eagle Haliaeetus albicilla during continuous midsummer daylight on open, treeless islands in coastal Northern Norway. We evaluated circadian rhythms, temporal overlap, exposure, and spatial distribution. The owls maintained a nocturnal activity pattern, possibly because slightly dimmer light around midnight offered favourable hunting conditions. The eagles were active throughout the 24‐hour period as opposed to the strictly diurnal rhythm reported elsewhere, thus increasing temporal overlap and the potential for interference competition between the two avian predators. This may indicate an asymmetry, with the owls facing the highest cost of interference competition. The presence of eagles combined with constant daylight in this open landscape may make the owls vulnerable to interspecific aggression, and contrary to the available literature, eagle owls rarely exposed themselves visually during territorial calls, possibly to avoid detection by eagles. We found indications of spatial segregation between owls and eagles reflecting differences in main prey, possibly in combination with habitat‐mediated avoidance. Eagle owl vocal activity peaked in the evening before a nocturnal peak in visual observations, when owls were active hunting, consistent with the hypothesis of a dusk chorus in nocturnal bird species. The owls may have had to trade‐off between calling and foraging during the few hours around midnight when slightly dimmer light reduced the detection risk while also providing better hunting conditions.  
  Address  
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  ISSN 0908-8857 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number GFZ @ kyba @ Serial 1881  
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Author Souman, J.L.; Tinga, A.M.; Te Pas, S.F.; van Ee, R.; Vlaskamp, B.N.S. url  doi
openurl 
  Title (up) Acute alerting effects of light: a systematic literature review Type Journal Article
  Year 2018 Publication Behavioural Brain Research Abbreviated Journal Behav Brain Res  
  Volume 337 Issue Pages 228-239  
  Keywords Human Health  
  Abstract Periodic, well timed exposure to light is important for our health and wellbeing. Light, in particular in the blue part of the spectrum, is thought to affect alertness both indirectly, by modifying circadian rhythms, and directly, giving rise to acute effects. We performed a systematic review of empirical studies on direct, acute effects of light on alertness to evaluate the reliability of these effects and to assess to what extent they depend on other factors, such as time of day, exposure duration and sleep pressure. In total, we identified 74 studies in which either light intensity, spectral distribution, or both were manipulated, and the effects on behavioral measures of alertness were evaluated, either subjectively or measured in performance tasks. The results show that increasing the intensity or the color temperature of polychromatic white light in general has been found to increase subjective ratings of alertness, though a substantial proportion of these studies failed to find significant effects. There is little evidence in the literature that these subjective alerting effects of light also translate into improvements on performance measures of alertness. For monochromatic or narrowband light exposure, some studies have shown improvement in reaction time tasks with exposure to blue light, but generally this was not accompanied by changes in subjective alertness. Thus, the alerting effects of light are far less clear than often suggested. We suggest that in future studies more attention should be paid to other factors that may influence the effects of light, such as chronotype, circadian phase, homeostatic state and prior light history.  
  Address Philips Research (Department Brain, Behavior & Cognition), Eindhoven, The Netherlands  
  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 0166-4328 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:28912014 Approved no  
  Call Number LoNNe @ kyba @ Serial 1727  
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Author Chellappa, S.L.; Steiner, R.; Oelhafen, P.; Lang, D.; Gotz, T.; Krebs, J.; Cajochen, C. url  doi
openurl 
  Title (up) Acute exposure to evening blue-enriched light impacts on human sleep Type Journal Article
  Year 2013 Publication Journal of Sleep Research Abbreviated Journal J Sleep Res  
  Volume 22 Issue 5 Pages 573-580  
  Keywords Human Health  
  Abstract Light in the short wavelength range (blue light: 446-483 nm) elicits direct effects on human melatonin secretion, alertness and cognitive performance via non-image-forming photoreceptors. However, the impact of blue-enriched polychromatic light on human sleep architecture and sleep electroencephalographic activity remains fairly unknown. In this study we investigated sleep structure and sleep electroencephalographic characteristics of 30 healthy young participants (16 men, 14 women; age range 20-31 years) following 2 h of evening light exposure to polychromatic light at 6500 K, 2500 K and 3000 K. Sleep structure across the first three non-rapid eye movement non-rapid eye movement – rapid eye movement sleep cycles did not differ significantly with respect to the light conditions. All-night non-rapid eye movement sleep electroencephalographic power density indicated that exposure to light at 6500 K resulted in a tendency for less frontal non-rapid eye movement electroencephalographic power density, compared to light at 2500 K and 3000 K. The dynamics of non-rapid eye movement electroencephalographic slow wave activity (2.0-4.0 Hz), a functional index of homeostatic sleep pressure, were such that slow wave activity was reduced significantly during the first sleep cycle after light at 6500 K compared to light at 2500 K and 3000 K, particularly in the frontal derivation. Our data suggest that exposure to blue-enriched polychromatic light at relatively low room light levels impacts upon homeostatic sleep regulation, as indexed by reduction in frontal slow wave activity during the first non-rapid eye movement episode.  
  Address Centre for Chronobiology, Psychiatric Hospital of the University of Basel, Basel, Switzerland; Cyclotron Research Center, University of Liege, Liege, Belgium  
  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 0962-1105 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:23509952 Approved no  
  Call Number GFZ @ kyba @ Serial 2201  
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Author Walker, W.H. 2nd; Borniger, J.C.; Gaudier-Diaz, M.M.; Hecmarie Melendez-Fernandez, O.; Pascoe, J.L.; Courtney DeVries, A.; Nelson, R.J. url  doi
openurl 
  Title (up) Acute exposure to low-level light at night is sufficient to induce neurological changes and depressive-like behavior Type Journal Article
  Year 2019 Publication Molecular Psychiatry Abbreviated Journal Mol Psychiatry  
  Volume Issue Pages  
  Keywords Human health; physiology; brain  
  Abstract The advent and wide-spread adoption of electric lighting over the past century has profoundly affected the circadian organization of physiology and behavior for many individuals in industrialized nations; electric lighting in homes, work environments, and public areas have extended daytime activities into the evening, thus, increasing night-time exposure to light. Although initially assumed to be innocuous, chronic exposure to light at night (LAN) is now associated with increased incidence of cancer, metabolic disorders, and affective problems in humans. However, little is known about potential acute effects of LAN. To determine whether acute exposure to low-level LAN alters brain function, adult male, and female mice were housed in either light days and dark nights (LD; 14 h of 150 lux:10 h of 0 lux) or light days and low level light at night (LAN; 14 h of 150 lux:10 h of 5 lux). Mice exposed to LAN on three consecutive nights increased depressive-like responses compared to mice housed in dark nights. In addition, female mice exposed to LAN increased central tendency in the open field. LAN was associated with reduced hippocampal vascular endothelial growth factor-A (VEGF-A) in both male and female mice, as well as increased VEGFR1 and interleukin-1beta mRNA expression in females, and reduced brain derived neurotrophic factor mRNA in males. Further, LAN significantly altered circadian rhythms (activity and temperature) and circadian gene expression in female and male mice, respectively. Altogether, this study demonstrates that acute exposure to LAN alters brain physiology and can be detrimental to well-being in otherwise healthy individuals.  
  Address Department of Rockefeller Neuroscience Institute, West Virginia University, Morgantown, WV, 26506, USA  
  Corporate Author Thesis  
  Publisher Nature Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1359-4184 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:31138889 Approved no  
  Call Number IDA @ john @ Serial 2509  
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Author Halfwerk, W.; Blaas, M.; Kramer, L.; Hijner, N.; Trillo, P.A.; Bernal, X.E.; Page, R.A.; Goutte, S.; Ryan, M.J.; Ellers, J. url  doi
openurl 
  Title (up) Adaptive changes in sexual signalling in response to urbanization Type Journal Article
  Year 2018 Publication Nature Ecology & Evolution Abbreviated Journal Nat Ecol Evol  
  Volume 3 Issue Pages 374-380  
  Keywords Animals  
  Abstract Urbanization can cause species to adjust their sexual displays, because the effectiveness of mating signals is influenced by environmental conditions. Despite many examples that show that mating signals in urban conditions differ from those in rural conditions, we do not know whether these differences provide a combined reproductive and survival benefit to the urban phenotype. Here we show that male tungara frogs have increased the conspicuousness of their calls, which is under strong sexual and natural selection by signal receivers, as an adaptive response to city life. The urban phenotype consequently attracts more females than the forest phenotype, while avoiding the costs that are imposed by eavesdropping bats and midges, which we show are rare in urban areas. Finally, we show in a translocation experiment that urban frogs can reduce risk of predation and parasitism when moved to the forest, but that forest frogs do not increase their sexual attractiveness when moved to the city. Our findings thus reveal that urbanization can rapidly drive adaptive signal change via changes in both natural and sexual selection pressures.  
  Address Department of Ecological Science, Vrije Universiteit, Amsterdam, The Netherlands  
  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 2397-334X ISBN Medium  
  Area Expedition Conference  
  Notes PMID:30532046 Approved no  
  Call Number GFZ @ kyba @ Serial 2136  
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