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Author Houser, K.W.
Title Darkness Type Journal Article
Year 2015 Publication Leukos Abbreviated Journal Leukos
Volume 11 Issue 4 Pages 173-173
Keywords Commentary; Darkness
Abstract
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 1550-2724 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number LoNNe @ christopher.kyba @ Serial 1169
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Author Jasser, S.A.; Blask, D.E.; Brainard, G.C.
Title Light during darkness and cancer: relationships in circadian photoreception and tumor biology Type Journal Article
Year 2006 Publication Cancer Causes & Control : CCC Abbreviated Journal Cancer Causes Control
Volume 17 Issue 4 Pages 515-523
Keywords Human Health; Animals; *Circadian Rhythm; *Darkness; Humans; *Light; Light Signal Transduction; Melatonin/physiology/secretion; Neoplasms/etiology/pathology/*physiopathology; Suprachiasmatic Nucleus/physiology
Abstract The relationship between circadian phototransduction and circadian-regulated processes is poorly understood. Melatonin, commonly a circadian phase marker, may play a direct role in a myriad of physiologic processes. The circadian rhythm for pineal melatonin secretion is regulated by the hypothalamic suprachiasmatic nucleus (SCN). Its neural source of light input is a unique subset of intrinsically photosensitive retinal ganglion cells expressing melanopsin, the primary circadian photopigment in rodents and primates. Action spectra of melatonin suppression by light have shown that light in the 446-477 nm range, distinct from the visual system's peak sensitivity, is optimal for stimulating the human circadian system. Breast cancer is the oncological disease entity whose relationship to circadian rhythm fluctuations has perhaps been most extensively studied. Empirical data has increasingly supported the hypothesis that higher risk of breast cancer in industrialized countries is partly due to increased exposure to light at night. Studies of tumor biology implicate melatonin as a potential mediator of this effect. Yet, causality between lifestyle factors and circadian tumor biology remains elusive and likely reflects significant variability with physiologic context. Continued rigorous empirical inquiry into the physiology and clinical implications of these habitual, integrated aspects of life is highly warranted at this time.
Address Department of Neurology, Light Research Program, Thomas Jefferson University, 1025 Walnut Street, Suite 507, Philadelphia, PA 19107, USA. samar.jasser@jefferson.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 0957-5243 ISBN Medium
Area Expedition Conference
Notes PMID:16596305 Approved no
Call Number LoNNe @ kagoburian @ Serial 766
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Author Kelber, A.; Balkenius, A.; Warrant, E.J.
Title Scotopic colour vision in nocturnal hawkmoths Type Journal Article
Year 2002 Publication Nature Abbreviated Journal Nature
Volume 419 Issue 6910 Pages 922-925
Keywords Animals; Behavior, Animal; Color; Color Perception/*physiology; Conditioning (Psychology)/physiology; Cues; *Darkness; Discrimination Learning/physiology; Humans; Light; Lighting; Moths/*physiology; Photic Stimulation; Photoreceptor Cells, Invertebrate/physiology; Reward; Sensitivity and Specificity; Ultraviolet Rays
Abstract Humans are colour-blind at night, and it has been assumed that this is true of all animals. But colour vision is as useful for discriminating objects at night as it is during the day. Here we show, through behavioural experiments, that the nocturnal hawkmoth Deilephila elpenor uses colour vision to discriminate coloured stimuli at intensities corresponding to dim starlight (0.0001 cd x m(-2)). It can do this even if the illumination colour changes, thereby showing colour constancy-a property of true colour vision systems. In identical conditions humans are completely colour-blind. Our calculations show that the possession of three photoreceptor classes reduces the absolute sensitivity of the eye, which indicates that colour vision has a high ecological relevance in nocturnal moths. In addition, the photoreceptors of a single ommatidium absorb too few photons for reliable discrimination, indicating that spatial and/or temporal summation must occur for colour vision to be possible. Taken together, our results show that colour vision occurs at nocturnal intensities in a biologically relevant context.
Address Department of Cell and Organism Biology, Vision Group, Lund University, Helgonavagen 3, S-22362 Lund, Sweden. almut.kelber@zool.lu.se
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 0028-0836 ISBN Medium
Area Expedition Conference
Notes PMID:12410310 Approved no
Call Number LoNNe @ kagoburian @ Serial 606
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Author Kempinger, L.; Dittmann, R.; Rieger, D.; Helfrich-Forster, C.
Title The nocturnal activity of fruit flies exposed to artificial moonlight is partly caused by direct light effects on the activity level that bypass the endogenous clock Type Journal Article
Year 2009 Publication Chronobiology International Abbreviated Journal Chronobiol Int
Volume 26 Issue 2 Pages 151-166
Keywords ARNTL Transcription Factors; Animals; Basic Helix-Loop-Helix Transcription Factors/genetics/metabolism; Behavior, Animal/physiology; Biological Clocks/*physiology; CLOCK Proteins; Circadian Rhythm/*physiology; Darkness; Drosophila Proteins/genetics/metabolism; Drosophila melanogaster/*physiology; *Light; *Moon; Motor Activity/*physiology; Nuclear Proteins/genetics/metabolism; Period Circadian Proteins; Photoperiod; Transcription Factors/genetics/metabolism
Abstract Artificial moonlight was recently shown to shift the endogenous clock of fruit flies and make them nocturnal. To test whether this nocturnal activity is partly due to masking effects of light, we exposed the clock-mutants per(01), tim(01), per(01);tim(01), cyc(01), and Clk(JRK) to light/dark and light/dim-light cycles and determined the activity level during the day and night. We found that under moonlit nights, all clock mutants shifted their activity significantly into the night, suggesting that this effect is independent of the clock. We also recorded the flies under continuous artificial moonlight and darkness to judge the effect of dim constant light on the activity level. All mutants, except Clk(JRK) flies, were significantly more active under artificial moonlight conditions than under complete darkness. Unexpectedly, we found residual rhythmicity of per(01) and especially tim(01) mutants under these conditions, suggesting that TIM and especially PER retained some activity in the absence of its respective partner. Nevertheless, as even the double mutants and the cyc(01) and Clk(JRK) mutants shifted their activity into the night, we conclude that dim light stimulates the activity of fruit flies in a clock-independent manner. Thus, nocturnal light has a twofold influence on flies: it shifts the circadian clock, and it increases nocturnal activity independently of the clock. The latter was also observed in some primates by others and might therefore be of a more general validity.
Address Institute of Zoology, University of Regensburg, Regensburg, 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 0742-0528 ISBN Medium
Area Expedition Conference
Notes PMID:19212834 Approved no
Call Number IDA @ john @ Serial 113
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Author Kocifaj, M.; Solano Lamphar, H.A.
Title Skyglow effects in UV and visible spectra: radiative fluxes Type Journal Article
Year 2013 Publication Journal of Environmental Management Abbreviated Journal J Environ Manage
Volume 127 Issue Pages 300-307
Keywords Animals; Darkness; Environmental Exposure/*analysis; *Light; Models, Theoretical; *Ultraviolet Rays; Light pollution; Optical thickness; Public lighting system; Two stream approximation
Abstract Several studies have tried to understand the mechanisms and effects of radiative transfer under different night-sky conditions. However, most of these studies are limited to the various effects of visible spectra. Nevertheless, the invisible parts of the electromagnetic spectrum can pose a more profound threat to nature. One visible threat is from what is popularly termed skyglow. Such skyglow is caused by injudiciously situated or designed artificial night lighting systems which degrade desired sky viewing. Therefore, since lamp emissions are not limited to visible electromagnetic spectra, it is necessary to consider the complete spectrum of such lamps in order to understand the physical behaviour of diffuse radiation at terrain level. In this paper, the downward diffuse radiative flux is computed in a two-stream approximation and obtained ultraviolet spectral radiative fluxes are inter-related with luminous fluxes. Such a method then permits an estimate of ultraviolet radiation if the traditionally measured illuminance on a horizontal plane is available. The utility of such a comparison of two spectral bands is shown, using the different lamp types employed in street lighting. The data demonstrate that it is insufficient to specify lamp type and its visible flux production independently of each other. Also the UV emissions have to be treated by modellers and environmental scientists because some light sources can be fairly important pollutants in the near ultraviolet. Such light sources can affect both the living organisms and ambient environment.
Address ICA, Slovak Academy of Sciences, 9, Dubravska Road, 845 03 Bratislava, Slovak Republic. kocifaj@savba.sk
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 0301-4797 ISBN Medium
Area Expedition Conference
Notes PMID:23792881 Approved no
Call Number IDA @ john @ Serial 265
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