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Author Wright, K.P.J.; McHill, A.W.; Birks, B.R.; Griffin, B.R.; Rusterholz, T.; Chinoy, E.D.
Title Entrainment of the human circadian clock to the natural light-dark cycle Type Journal Article
Year 2013 Publication 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 (up) LoNNe @ christopher.kyba @ Serial 505
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Author Bullough, J.D.; Donnell, E.T.; Rea, M.S.
Title To illuminate or not to illuminate: roadway lighting as it affects traffic safety at intersections Type Journal Article
Year 2013 Publication Accident; Analysis and Prevention Abbreviated Journal Accid Anal Prev
Volume 53 Issue Pages 65-77
Keywords Lighting; Accident Prevention/*methods; Accidents, Traffic/*prevention & control/psychology/statistics & numerical data; Cross-Sectional Studies; *Environment Design; Humans; *Lighting; Minnesota; Models, Statistical; Photoperiod; Psychomotor Performance; Regression Analysis; Safety/statistics & numerical data; Visual Perception
Abstract A two-pronged effort to quantify the impact of lighting on traffic safety is presented. In the statistical approach, the effects of lighting on crash frequency for different intersection types in Minnesota were assessed using count regression models. The models included many geometric and traffic control variables to estimate the association between lighting and nighttime and daytime crashes and the resulting night-to-day crash ratios. Overall, the presence of roadway intersection lighting was found to be associated with an approximately 12% lower night-to-day crash ratio than unlighted intersections. In the parallel analytical approach, visual performance analyses based on roadway intersection lighting practices in Minnesota were made for the same intersection types investigated in the statistical approach. The results of both approaches were convergent, suggesting that visual performance improvements from roadway lighting could serve as input for predicting improvements in crash frequency. A provisional transfer function allows transportation engineers to evaluate alternative lighting systems in the design phase so selections based on expected benefits and costs can be made.
Address Lighting Research Center, Rensselaer Polytechnic Institute, 21 Union Street, Troy, NY 12180, USA
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 0001-4575 ISBN Medium
Area Expedition Conference
Notes PMID:23377085 Approved no
Call Number (up) LoNNe @ kagoburian @ Serial 627
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Author Monsere, C.M.; Fischer, E.L.
Title Safety effects of reducing freeway illumination for energy conservation Type Journal Article
Year 2008 Publication Accident; Analysis and Prevention Abbreviated Journal Accid Anal Prev
Volume 40 Issue 5 Pages 1773-1780
Keywords Lighting; Accidents, Traffic/*statistics & numerical data; *Automobile Driving; *Conservation of Energy Resources; Environment Design; Humans; *Lighting; Models, Statistical; Oregon; Safety; Wounds and Injuries/epidemiology
Abstract The addition of illumination where none was present is generally believed to have a positive effect on motor vehicle safety; reducing the frequency, as well as the severity of crashes. The operational cost of illumination, however, can make it a candidate for conservation during periods of high energy costs. In response to a forecasted energy shortage, the Oregon Department of Transportation selectively reduced illumination on interstate highways as part of an energy-saving effort. The reductions occurred at 44 interchanges and along 5.5 miles of interstate highway. This paper presents the results of a crash-based analysis of the changes in safety performance using an empirical-Bayes observational methodology. The study found an increase in reported crashes where the lineal lighting was reduced both in total crashes (28.95%, P=0.05) and injury night crashes (39.21%, P=0.07). Where full interchange lighting was reduced to partial lighting, a 2.46% increase (P=0.007) in total night crashes was observed. Injury night crashes, however, decreased by 12.16% (P<0.001) though day injury crashes also decreased at these locations. Unexpectedly, for interchanges where illumination was reduced from partial plus to partial, a 35.24% decrease (P<0.001) in total crashes and 39.98 (P<0.001) decrease in injury night crashes was found, though again, day crashes also decreased.
Address Department of Civil & Environmental Engineering, Portland State University, P.O. Box 751, Portland, OR 97207-0751, USA. monsere@pdx.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 0001-4575 ISBN Medium
Area Expedition Conference
Notes PMID:18760107 Approved no
Call Number (up) LoNNe @ kagoburian @ Serial 643
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Author Lerchl, A.; Schindler, C.; Eichhorn, K.; Kley, F.; Erren, T.C.
Title Indirect blue light does not suppress nocturnal salivary melatonin in humans in an automobile setting Type Journal Article
Year 2009 Publication Journal of Pineal Research Abbreviated Journal J Pineal Res
Volume 47 Issue 2 Pages 143-146
Keywords Human Health; Adolescent; Adult; *Automobiles; Circadian Rhythm/physiology; Humans; *Lighting; Male; Melatonin/metabolism/*secretion; Salivary Glands/*secretion; Statistics, Nonparametric
Abstract In 2007, the International Agency for Research on Cancer (IARC) classified shift work that involves circadian disruption as being probably carcinogenic to humans (Group 2A). In this context, light exposure during the night plays a key role because it can suppress nocturnal melatonin levels when exposures exceed a certain threshold. Blue light around 464 nm is most effective in suppressing melatonin because of the spectral sensitivity of melanopsin, a recently discovered photopigment in retinal ganglion cells; the axons of these cells project to the suprachiasmatic nucleus, a circadian master clock in the brain. Due to advances in light technologies, normal tungsten light bulbs are being replaced by light-emitting diodes which produce quasi-monochromatic or white light. The objective of this study was to assess whether the light-melanopsin-melatonin axis might be affected in automobiles at night which employ the new generation diodes. To this end, we have tested in an experimental automobile setting whether indirect blue light (lambda(max) = 465 nm) at an intensity of 0.22 or 1.25 lx can suppress salivary melatonin levels in 12 male volunteers (age range 17-27 years) who served as their own controls. Daytime levels were low (2.7 +/- 0.5 pg/mL), and night-time levels without light exposure were high (14.5 +/- 1.1 pg/mL), as expected. Low-intensity light exposures had no significant effect on melatonin levels (0.22 lx: 17.2 +/- 2.8 pg/mL; P > 0.05; 1.25 lx: 12.6 +/- 2.0 pg/mL; P > 0.05). It is concluded that indirect blue light exposures in automobiles up to 1.25 lx do not cause unintentional chronodisruption via melatonin suppression.
Address School of Engineering and Science, Jacobs University, D-28759 Bremen, Germany. a.lerchl@jacobs-university.de
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 0742-3098 ISBN Medium
Area Expedition Conference
Notes PMID:19555449 Approved no
Call Number (up) LoNNe @ kagoburian @ Serial 777
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Author Stevens, R.G.; Blask, D.E.; Brainard, G.C.; Hansen, J.; Lockley, S.W.; Provencio, I.; Rea, M.S.; Reinlib, L.
Title Meeting report: the role of environmental lighting and circadian disruption in cancer and other diseases Type Journal Article
Year 2007 Publication Environmental Health Perspectives Abbreviated Journal Environ Health Perspect
Volume 115 Issue 9 Pages 1357-1362
Keywords Human Health; Animals; *Circadian Rhythm; Environmental Exposure; Humans; *Lighting/adverse effects; *Neoplasms/etiology; Research; breast cancer; circadian rhythms; clock genes; lighting; melatonin; phototransduction; pineal gland
Abstract Light, including artificial light, has a range of effects on human physiology and behavior and can therefore alter human physiology when inappropriately timed. One example of potential light-induced disruption is the effect of light on circadian organization, including the production of several hormone rhythms. Changes in light-dark exposure (e.g., by nonday occupation or transmeridian travel) shift the timing of the circadian system such that internal rhythms can become desynchronized from both the external environment and internally with each other, impairing our ability to sleep and wake at the appropriate times and compromising physiologic and metabolic processes. Light can also have direct acute effects on neuroendocrine systems, for example, in suppressing melatonin synthesis or elevating cortisol production that may have untoward long-term consequences. For these reasons, the National Institute of Environmental Health Sciences convened a workshop of a diverse group of scientists to consider how best to conduct research on possible connections between lighting and health. According to the participants in the workshop, there are three broad areas of research effort that need to be addressed. First are the basic biophysical and molecular genetic mechanisms for phototransduction for circadian, neuroendocrine, and neurobehavioral regulation. Second are the possible physiologic consequences of disrupting these circadian regulatory processes such as on hormone production, particularly melatonin, and normal and neoplastic tissue growth dynamics. Third are effects of light-induced physiologic disruption on disease occurrence and prognosis, and how prevention and treatment could be improved by application of this knowledge.
Address Department of Community Medicine, University of Connecticut Health Center, Farmington, Connecticut 06030-6325, USA. bugs@uchc.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 0091-6765 ISBN Medium
Area Expedition Conference
Notes PMID:17805428; PMCID:PMC1964886 Approved no
Call Number (up) LoNNe @ kagoburian @ Serial 821
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