|   | 
Details
   web
Records
Author Eriksen, A.; Wabakken, P.
Title 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 (up) 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
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0908-8857 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 1881
Permanent link to this record
 

 
Author Holveck, M.-J.; Grégoire, A.; Doutrelant, C.; Lambrechts, M.M.
Title Nest height is affected by lamppost lighting proximity in addition to nestbox size in urban great tits Type Journal Article
Year 2018 Publication Journal of Avian Biology Abbreviated Journal (up) J Avian Biol
Volume in press Issue Pages
Keywords Animals
Abstract Both natural and artificial light have proximate influences on many aspects of avian biology, physiology and behaviour. To date artificial light at night is mostly considered as being a nuisance disrupting for instance sleep and reproduction of diurnal species. Here, we investigate if lamppost night lighting affects cavity‐nesting bird species inside their breeding cavity. Nest height in secondary cavity‐nesting species is the result of trade‐offs between several selective forces. Predation is the prevailing force leading birds to build thin nests to increase the distance towards the entrance hole. A thin nest may also limit artificial light exposure at night. Yet, a minimum level of daylight inside nesting cavities is necessary for adequate visual communication and/or offspring development. Against this background, we hypothesised that avian nest‐building behaviour varies in response to a change in night lighting. We monitored nest height of urban great tits (Parus major) during six years and found that it varied with artificial light proximity. The birds built thinner nests inside nestboxes of various sizes in response to increasing lamppost night light availability at the nest. In large nestboxes, the nests were also thinner when a lamppost was present in the territory. Whether this relationship between artificial night lighting and nest height reflects a positive or negative effect of urbanisation is discussed in the light of recent experimental studies conducted in rural populations by other research groups.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0908-8857 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 2062
Permanent link to this record
 

 
Author Mason, I.C.; Boubekri, M.; Figueiro, M.G.; Hasler, B.P.; Hattar, S.; Hill, S.M.; Nelson, R.J.; Sharkey, K.M.; Wright, K.P.; Boyd, W.A.; Brown, M.K.; Laposky, A.D.; Twery, M.J.; Zee, P.C.
Title Circadian Health and Light: A Report on the National Heart, Lung, and Blood Institute's Workshop Type Journal Article
Year 2018 Publication Journal of Biological Rhythms Abbreviated Journal (up) J Biol Rhythms
Volume 33 Issue 5 Pages 451-457
Keywords Human Health
Abstract Despite the omnipresence of artificial and natural light exposure, there exists little guidance in the United States and elsewhere on light exposure in terms of timing, intensity, spectrum, and other light characteristics known to affect human health, performance, and well-being; in parallel, there is little information regarding the quantity and characteristics of light exposure that people receive. To address this, the National Center on Sleep Disorders Research, in the Division of Lung Diseases, National Heart, Lung, and Blood Institute, held a workshop in August 2016 on circadian health and light. Workshop participants discussed scientific research advances on the effects of light on human physiology, identified remaining knowledge gaps in these research areas, and articulated opportunities to use appropriate lighting to protect and improve circadian-dependent health. Based on this workshop, participants put forth the following strategic intent, objectives, and strategies to guide discovery, measurement, education, and implementation of the appropriate use of light to achieve, promote, and maintain circadian health in modern society.
Address Center for Circadian and Sleep Medicine, Department of Neurology, Northwestern University Feinberg School of Medicine, Chicago, Illinois
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 0748-7304 ISBN Medium
Area Expedition Conference
Notes PMID:30033850 Approved no
Call Number GFZ @ kyba @ Serial 1975
Permanent link to this record
 

 
Author Souman, J.L.; Borra, T.; de Goijer, I.; Schlangen, L.J.M.; Vlaskamp, B.N.S.; Lucassen, M.P.
Title Spectral Tuning of White Light Allows for Strong Reduction in Melatonin Suppression without Changing Illumination Level or Color Temperature Type Journal Article
Year 2018 Publication Journal of Biological Rhythms Abbreviated Journal (up) J Biol Rhythms
Volume 33 Issue 4 Pages 420-431
Keywords Human Health; Lighting
Abstract Studies with monochromatic light stimuli have shown that the action spectrum for melatonin suppression exhibits its highest sensitivity at short wavelengths, around 460 to 480 nm. Other studies have demonstrated that filtering out the short wavelengths from white light reduces melatonin suppression. However, this filtering of short wavelengths was generally confounded with reduced light intensity and/or changes in color temperature. Moreover, it changed the appearance from white light to yellow/orange, rendering it unusable for many practical applications. Here, we show that selectively tuning a polychromatic white light spectrum, compensating for the reduction in spectral power between 450 and 500 nm by enhancing power at even shorter wavelengths, can produce greatly different effects on melatonin production, without changes in illuminance or color temperature. On different evenings, 15 participants were exposed to 3 h of white light with either low or high power between 450 and 500 nm, and the effects on salivary melatonin levels and alertness were compared with those during a dim light baseline. Exposure to the spectrum with low power between 450 and 500 nm, but high power at even shorter wavelengths, did not suppress melatonin compared with dim light, despite a large difference in illuminance (175 vs. <5 lux). In contrast, exposure to the spectrum with high power between 450 and 500 nm (also 175 lux) resulted in almost 50% melatonin suppression. For alertness, no significant differences between the 3 conditions were observed. These results open up new opportunities for lighting applications that allow for the use of electrical lighting without disturbance of melatonin production.
Address Philips Lighting Research, Department Lighting Applications, Eindhoven, 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 0748-7304 ISBN Medium
Area Expedition Conference
Notes PMID:29984614 Approved no
Call Number GFZ @ kyba @ Serial 1985
Permanent link to this record
 

 
Author Flores, D.E.F.L.; Oda, G.A.
Title Novel Light/Dark Regimens with Minimum Light Promote Circadian Disruption: Simulations with a Model Oscillator Type Journal Article
Year 2018 Publication Journal of Biological Rhythms Abbreviated Journal (up) J Biol Rhythms
Volume in press Issue Pages
Keywords Animals
Abstract Artificial lab manipulation of LD cycles has enabled simulations of the disruptive conditions found in modern human societies, such as jet-lag, night-work and light at night. New techniques using animal models have been developed, and these can greatly improve our understanding of circadian disruption. Some of these techniques, such as in vivo bioluminescence assays, require minimum external light. This requirement is challenging because the usual lighting protocols applied in circadian desynchronization experiments rely on considerable light input. Here, we present a novel LD regimen that can disrupt circadian rhythms with little light per day, based on computer simulations of a model limit-cycle oscillator. The model predicts that a single light pulse per day has the potential to disturb rhythmicity when pulse times are randomly distributed within an interval. Counterintuitively, the rhythm still preserves an underlying 24-h periodicity when this interval is as large as 14 h, indicating that day/night cues are still detectable. Only when pulses are spread throughout the whole 24-h day does the rhythm lose any day-to-day period correlation. In addition, the model also reveals that stronger pulses of brighter light should exacerbate the disrupting effects. We propose the use of this LD schedule-which would be compatible with the requirements of in vivo bioluminescence assays-to help understand circadian disruption and associated illnesses.
Address Instituto de Biociencias, Universidade de Sao Paulo, Sao Paulo, SP, Brazil
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 0748-7304 ISBN Medium
Area Expedition Conference
Notes PMID:30595077 Approved no
Call Number GFZ @ kyba @ Serial 2146
Permanent link to this record