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Author Nickla, D.L.
Title Ocular diurnal rhythms and eye growth regulation: where we are 50 years after Lauber Type Journal Article
Year 2013 Publication Experimental eye Research Abbreviated Journal Exp Eye Res
Volume 114 Issue Pages 25-34
Keywords Vision; Human Health; Review
Abstract Many ocular processes show diurnal oscillations that optimize retinal function under the different conditions of ambient illumination encountered over the course of the 24 h light/dark cycle. Abolishing the diurnal cues by the use of constant darkness or constant light results in excessive ocular elongation, corneal flattening, and attendant refractive errors. A prevailing hypothesis is that the absence of the Zeitgeber of light and dark alters ocular circadian rhythms in some manner, and results in an inability of the eye to regulate its growth in order to achieve emmetropia, the matching of the front optics to eye length. Another visual manipulation that results in the eye growth system going into a “default” mode of excessive growth is form deprivation, in which a translucent diffuser deprives the eye of visual transients (spatial or temporal) while not significantly reducing light levels; these eyes rapidly elongate and become myopic. It has been hypothesized that form deprivation might constitute a type of “constant condition” whereby the absence of visual transients drives the eye into a similar default mode as that in response to constant light or dark. Interest in the potential influence of light cycles and ambient lighting in human myopia development has been spurred by a recent study showing a positive association between the amount of time that children spent outdoors and a reduced prevalence of myopia. The growing eyes of chickens and monkeys show a diurnal rhythm in axial length: Eyes elongate more during the day than during the night. There is also a rhythm in choroidal thickness that is in approximate anti-phase to the rhythm in eye length. The phases are altered in eyes growing too fast, in response to form deprivation or negative lenses, or too slowly, in response to myopic defocus, suggesting an influence of phase on the emmetropization system. Other potential rhythmic influences include dopamine and melatonin, which form a reciprocal feedback loop, and signal “day” and “night” respectively. Retinal dopamine is reduced during the day in form deprived myopic eyes, and dopamine D2 agonists inhibit ocular growth in animal models. Rhythms in intraocular pressure as well, may influence eye growth, perhaps as a mechanical stimulus triggering changes in scleral extracellular matrix synthesis. Finally, evidence shows varying influences of environmental lighting parameters on the emmetropization system, such as high intensity light being protective against myopia in chickens. This review will cover the evidence for the possible influence of these various factors on ocular growth. The recognition that ocular rhythms may play a role in emmetropization is a first step toward understanding how they may be manipulated in treatment therapies to prevent myopia in humans.
Address New England College of Optometry, Department of Biosciences, 424 Beacon Street, Boston, MA 02115, USA. nicklad@neco.edu
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ISSN 0014-4835 ISBN Medium
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Notes PMID:23298452; PMCID:PMC3742730 Approved no
Call Number GFZ @ kyba @ Serial (down) 1987
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Author Li, X.; Chen, F.; Chen, X.
Title Satellite-Observed Nighttime Light Variation as Evidence for Global Armed Conflicts Type Journal Article
Year 2013 Publication IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing Abbreviated Journal IEEE J. Sel. Top. Appl. Earth Observations Remote Sensing
Volume 6 Issue 5 Pages 2302-2315
Keywords Remote Sensing; Society
Abstract The objective of this research is to investigate the potential of nighttime light images, acquired with Defense Meteorological Satellite Program Operational Linescan System (DMSP-OLS), in evaluating global armed conflicts. To achieve this purpose, we assessed the relationship between armed conflicts and the satellite-observed nighttime light variation over 159 countries through annual composites of the nighttime light images. Firstly, a light ratio index was developed to reduce the data inconsistency of annual nighttime light images during 1992-2010. Then 12 countries were selected as examples for a primary investigation, and we found the outbreak of a war can reduce the light and the ceasefire can increase the light from the remote sensing images, which indicates armed conflict events always have significant impact on the nighttime light. Based on this assertion, a nighttime light variation index (NLVI) was developed to quantify the variation of the time series nighttime light. Then using conditional probability analysis, the probability of a country suffering from armed conflicts increases with increase of NLVI. Particularly, when the NLVI value is in a very high level as defined, 80% of the countries have experienced armed conflicts. Furthermore, using correlation analysis, the number of global armed conflicts is highly correlated with the global NLVI in temporal dimension, with a correlation coefficient larger than 0.77. In summary, the potential of nighttime light images in armed conflict evaluation is extended from a regional scale to a global scale by this study.
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ISSN 1939-1404 ISBN Medium
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Notes Approved no
Call Number GFZ @ kyba @ Serial (down) 1876
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Author Stokkan, K.-A.; Folkow, L.; Dukes, J.; Neveu, M.; Hogg, C.; Siefken, S.; Dakin, S.C.; Jeffery, G.
Title Shifting mirrors: adaptive changes in retinal reflections to winter darkness in Arctic reindeer Type Journal Article
Year 2013 Publication Proceedings. Biological Sciences Abbreviated Journal Proc Biol Sci
Volume 280 Issue 1773 Pages 20132451
Keywords Animals; Skyglow
Abstract Arctic reindeer experience extreme changes in environmental light from continuous summer daylight to continuous winter darkness. Here, we show that they may have a unique mechanism to cope with winter darkness by changing the wavelength reflection from their tapetum lucidum (TL). In summer, it is golden with most light reflected back directly through the retina, whereas in winter it is deep blue with less light reflected out of the eye. The blue reflection in winter is associated with significantly increased retinal sensitivity compared with summer animals. The wavelength of reflection depends on TL collagen spacing, with reduced spacing resulting in shorter wavelengths, which we confirmed in summer and winter animals. Winter animals have significantly increased intra-ocular pressure, probably produced by permanent pupil dilation blocking ocular drainage. This may explain the collagen compression. The resulting shift to a blue reflection may scatter light through photoreceptors rather than directly reflecting it, resulting in elevated retinal sensitivity via increased photon capture. This is, to our knowledge, the first description of a retinal structural adaptation to seasonal changes in environmental light. Increased sensitivity occurs at the cost of reduced acuity, but may be an important adaptation in reindeer to detect moving predators in the dark Arctic winter.
Address Department of Arctic and Marine Biology, University of Tromso, , Tromso, Norway, Institute of Ophthalmology, University College London, , 11-43 Bath Street, London EC1V 9EL, UK, Moorfields Eye Hospital, , London, UK
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ISSN 0962-8452 ISBN Medium
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Notes PMID:24174115; PMCID:PMC3826237 Approved no
Call Number LoNNe @ kyba @ Serial (down) 1636
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Author Shimmura, Tsuyoshi; Yoshimura, Takashi
Title Circadian clock determines the timing of rooster crowing Type Journal Article
Year 2013 Publication Current Biology Abbreviated Journal
Volume 23 Issue 6 Pages R231–R233
Keywords animals; rooster; bird
Abstract Crowing of roosters is described by onomatopoetic terms such as ‘cock-a-doodle-doo’ (English), ‘ki-ke-ri-ki’ (German), and ‘ko-ke-kok-koh’ (Japanese). Rooster crowing is a symbol of the break of dawn in many countries. Indeed, crowing is frequently observed in the morning [1] . However, people also notice that crowing is sometimes observed at other times of day. Therefore, it is yet unclear whether crowing is under the control of an internal biological clock, or is simply caused by external stimuli. Here we show that predawn crowing is under the control of a circadian clock. Although external stimuli such as light and crowing by other individuals also induce roosters’ crowing, the magnitude of this induction is also regulated by a circadian clock.
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Call Number LoNNe @ schroer @ Serial (down) 1600
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Author Riley, W. D.; Davison, P. I.; Maxwell, D. L.; Bendall, B.
Title Street lighting delays and disrupts the dispersal of Atlantic salmon (Salmo salar) fry Type Journal Article
Year 2013 Publication Biological conservation Abbreviated Journal
Volume 158 Issue Pages 140-146
Keywords animals; fish; animal behaviour
Abstract There has been a decline in the abundance of Atlantic salmon (Salmo salar) despite significant conservation measures designed to reduce fishing mortality. Populations at the southern edge of their historical distribution, where anthropogenic impacts on the freshwater environment may be greater, have suffered the largest decline. In this investigation, we compared the timing of Atlantic salmon fry dispersal from incubators in an aquarium under control and ecologically relevant broad spectrum street-lit conditions (median night light intensity = 12 lx). Fry dispersal occurred 2.8 days later (F = 82.9, df = 1,8, p < 0.001), and on average the fry were smaller at dispersal (0.017 g, se = 0.0012, p < 0.001, n = 730), in the incubators exposed to street lighting. Significant disruption to the diel pattern of fry dispersal was also observed. Dispersal under control conditions was significantly directed around a mean time of 4:17 h after dusk (p < 0.001, r = 0.76, n = 1990) with very few fry (<2%) dispersing during daylight hours. Under street lighting, the dispersal of fry was significantly delayed (mean time 6:38 h after dusk; p < 0.001, r = 0.39, n = 2413) with a significant proportion (32%) dispersing during daylight hours. Survival to dispersal in the controlled aquarium conditions was not lower under street-lit conditions (p = 0.21, n = 5000 eggs across 10 incubators). However, in the wild, the period between fry emergence and the establishment of feeding territories is considered to be of critical importance in the dynamics of salmonid populations and any disruption may reduce fitness.
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Notes Approved no
Call Number LoNNe @ schroer @ Serial (down) 1599
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