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Author Mouland, J.W.; Martial, F.; Watson, A.; Lucas, R.J.; Brown, T.M. url  doi
openurl 
  Title Cones Support Alignment to an Inconsistent World by Suppressing Mouse Circadian Responses to the Blue Colors Associated with Twilight Type Journal Article
  Year 2019 Publication (up) Current Biology Abbreviated Journal Current Biology  
  Volume 29 Issue 24 Pages 4260-4267.e4  
  Keywords Animals; Circadian Rhythm; mouse models; cones  
  Abstract In humans, short-wavelength light evokes larger circadian responses than longer wavelengths. This reflects the fact that melanopsin, a key contributor to circadian assessments of light intensity, most efficiently captures photons around 480 nm and gives rise to the popular view that ‘‘blue’’ light exerts the strongest effects on the clock. However, in the natural world, there is often no direct correlation be- tween perceived color (as reported by the cone-based visual system) and melanopsin excitation. Accordingly, although the mammalian clock does receive cone-based chromatic signals, the influence of color on circadian responses to light remains unclear. Here, we define the nature and functional significance of chromatic influences on the mouse circadian sys- tem. Using polychromatic lighting and mice with altered cone spectral sensitivity (Opn1mwR), we generate conditions that differ in color (i.e., ratio of L- to S-cone opsin activation) while providing identical melanopsin and rod activation. When biased toward S-opsin activation (appearing ‘‘blue’’), these stimuli reliably produce weaker circadian behavioral responses than those favoring L-opsin (‘‘yellow’’). This influence of color (which is absent in animals lacking cone phototransduction; Cnga3/) aligns with natural changes in spectral composition over twilight, where decreasing solar angle is accompanied by a strong blue shift. Accordingly, we find that naturalistic color changes support circadian alignment when environmental conditions render diurnal variations in light intensity weak/ambiguous sources of timing information. Our data thus establish how color contributes to circadian entrainment in mammals and provide important new insight to inform the design of lighting environments that benefit health.  
  Address Centre for Biological Timing, Faculty of Biology, Medicine & Health, University of Manchester, Oxford Road, Manchester M13 9PT, UK; timothy.brown(at)manchester.ac.uk  
  Corporate Author Thesis  
  Publisher Cell Place of Publication Editor  
  Language English Summary Language English Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 0960-9822 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number IDA @ john @ Serial 2785  
Permanent link to this record
 

 
Author Wright, K.P.J.; McHill, A.W.; Birks, B.R.; Griffin, B.R.; Rusterholz, T.; Chinoy, E.D. url  doi
openurl 
  Title Entrainment of the human circadian clock to the natural light-dark cycle Type Journal Article
  Year 2013 Publication (up) Current Biology : CB Abbreviated Journal Curr Biol  
  Volume 23 Issue 16 Pages 1554-1558  
  Keywords Human Health; Adult; Circadian Clocks/*radiation effects; Female; Humans; *Lighting; Male; *Photoperiod; *Sunlight; Young Adult; Circadian Rhythm  
  Abstract The electric light is one of the most important human inventions. Sleep and other daily rhythms in physiology and behavior, however, evolved in the natural light-dark cycle [1], and electrical lighting is thought to have disrupted these rhythms. Yet how much the age of electrical lighting has altered the human circadian clock is unknown. Here we show that electrical lighting and the constructed environment is associated with reduced exposure to sunlight during the day, increased light exposure after sunset, and a delayed timing of the circadian clock as compared to a summer natural 14 hr 40 min:9 hr 20 min light-dark cycle camping. Furthermore, we find that after exposure to only natural light, the internal circadian clock synchronizes to solar time such that the beginning of the internal biological night occurs at sunset and the end of the internal biological night occurs before wake time just after sunrise. In addition, we find that later chronotypes show larger circadian advances when exposed to only natural light, making the timing of their internal clocks in relation to the light-dark cycle more similar to earlier chronotypes. These findings have important implications for understanding how modern light exposure patterns contribute to late sleep schedules and may disrupt sleep and circadian clocks.  
  Address Sleep and Chronobiology Laboratory, Department of Integrative Physiology, University of Colorado Boulder, Boulder, CO 80309-0354, USA. kenneth.wright@colorado.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 0960-9822 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:23910656; PMCID:PMC4020279 Approved no  
  Call Number LoNNe @ christopher.kyba @ Serial 505  
Permanent link to this record
 

 
Author Stothard, E.R.; McHill, A.W.; Depner, C.M.; Birks, B.R.; Moehlman, T.M.; Ritchie, H.K.; Guzzetti, J.R.; Chinoy, E.D.; LeBourgeois, M.K.; Axelsson, J.; Wright, K.P.J. url  doi
openurl 
  Title Circadian Entrainment to the Natural Light-Dark Cycle across Seasons and the Weekend Type Journal Article
  Year 2017 Publication (up) Current Biology : CB Abbreviated Journal Curr Biol  
  Volume 27 Issue 4 Pages 508-513  
  Keywords Human Health  
  Abstract Reduced exposure to daytime sunlight and increased exposure to electrical lighting at night leads to late circadian and sleep timing [1-3]. We have previously shown that exposure to a natural summer 14 hr 40 min:9 hr 20 min light-dark cycle entrains the human circadian clock to solar time, such that the internal biological night begins near sunset and ends near sunrise [1]. Here we show that the beginning of the biological night and sleep occur earlier after a week's exposure to a natural winter 9 hr 20 min:14 hr 40 min light-dark cycle as compared to the modern electrical lighting environment. Further, we find that the human circadian clock is sensitive to seasonal changes in the natural light-dark cycle, showing an expansion of the biological night in winter compared to summer, akin to that seen in non-humans [4-8]. We also show that circadian and sleep timing occur earlier after spending a weekend camping in a summer 14 hr 39 min:9 hr 21 min natural light-dark cycle compared to a typical weekend in the modern environment. Weekend exposure to natural light was sufficient to achieve approximately 69% of the shift in circadian timing we previously reported after a week's exposure to natural light [1]. These findings provide evidence that the human circadian clock adapts to seasonal changes in the natural light-dark cycle and is timed later in the modern environment in both winter and summer. Further, we demonstrate that earlier circadian timing can be rapidly achieved through natural light exposure during a weekend spent camping.  
  Address Department of Integrative Physiology, Sleep and Chronobiology Laboratory, University of Colorado Boulder, Boulder, CO 80309-0354, USA. Electronic address: kenneth.wright@colorado.edu  
  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:28162893 Approved no  
  Call Number LoNNe @ kyba @ Serial 1633  
Permanent link to this record
 

 
Author Sanders, D.; Kehoe, R.; Cruse, D.; van Veen, F.J.F.; Gaston, K.J. url  doi
openurl 
  Title Low Levels of Artificial Light at Night Strengthen Top-Down Control in Insect Food Web Type Journal Article
  Year 2018 Publication (up) Current Biology : CB Abbreviated Journal Curr Biol  
  Volume 28 Issue 15 Pages 2474-2478.e3  
  Keywords Ecology; Animals  
  Abstract Artificial light has transformed the nighttime environment of large areas of the earth, with 88% of Europe and almost 50% of the United States experiencing light-polluted night skies [1]. The consequences for ecosystems range from exposure to high light intensities in the vicinity of direct light sources to the very widespread but lower lighting levels further away [2]. While it is known that species exhibit a range of physiological and behavioral responses to artificial nighttime lighting [e.g., 3-5], there is a need to gain a mechanistic understanding of whole ecological community impacts [6, 7], especially to different light intensities. Using a mesocosm field experiment with insect communities, we determined the impact of intensities of artificial light ranging from 0.1 to 100 lux on different trophic levels and interactions between species. Strikingly, we found the strongest impact at low levels of artificial lighting (0.1 to 5 lux), which led to a 1.8 times overall reduction in aphid densities. Mechanistically, artificial light at night increased the efficiency of parasitoid wasps in attacking aphids, with twice the parasitism rate under low light levels compared to unlit controls. However, at higher light levels, parasitoid wasps spent longer away from the aphid host plants, diminishing this increased efficiency. Therefore, aphids reached higher densities under increased light intensity as compared to low levels of lighting, where they were limited by higher parasitoid efficiency. Our study highlights the importance of different intensities of artificial light in driving the strength of species interactions and ecosystem functions.  
  Address Environment and Sustainability Institute, University of Exeter, Penryn, Penryn, Cornwall TR10 9FE, UK  
  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 0960-9822 ISBN Medium  
  Area Expedition Conference  
  Notes PMID:30057304 Approved no  
  Call Number GFZ @ kyba @ Serial 2518  
Permanent link to this record
 

 
Author Kumar, P.; Ashawat, M.S.; Pandit, V.; Sharma, D.K. url  doi
openurl 
  Title Artificial Light Pollution at Night: A Risk for Normal Circadian Rhythm and Physiological Functions in Humans Type Journal Article
  Year 2019 Publication (up) Current Environmental Engineering Abbreviated Journal Cee  
  Volume 6 Issue 2 Pages 111-125  
  Keywords Human Health; Review  
  Abstract From the past three to four decades, ecologists and scientists have exhaustively studied the effect of increased artificial light pollution at night on the ecological and physiological behavior of mammals. The Suprachiasmatic Nuclei (SCN) or master clock in the brain of mammals including humans synchronizes the physiological functions with the light: dark cycle. The prolongation of light period in the light: dark cycle disrupts the circadian rhythm of mammals causing several negative or modified physiological consequences. Changed physiological level of melatonin, an important endocrine hormone, had been identified as an important factor causing different consequences such as cancer, diabetes mellitus, metabolic disturbances, oxidative stress, and depression. The presence of artificial light at night is the demand of the era but thoughts must be given to the prevention of consequences due to artificial light pollution and ‘how much is needed’. The review paper discusses the effect of artificial light pollution on the biological clock of humans and associated negative physiological consequences. Further, the paper also briefly discusses the economics of light pollution and measures needed to prevent physiological disorders in humans.  
  Address  
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  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2212-7178 ISBN Medium  
  Area Expedition Conference  
  Notes Approved no  
  Call Number GFZ @ kyba @ Serial 2695  
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