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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 (up) 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
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 0014-4835 ISBN Medium
Area Expedition Conference
Notes PMID:23298452; PMCID:PMC3742730 Approved no
Call Number GFZ @ kyba @ Serial 1987
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Author Dominoni, D.M.; Goymann, W.; Helm, B.; Partecke, J.
Title Urban-like night illumination reduces melatonin release in European blackbirds (Turdus merula): implications of city life for biological time-keeping of songbirds Type Journal Article
Year 2013 Publication Frontiers in Zoology Abbreviated Journal (up) Front Zool
Volume 10 Issue 1 Pages 60
Keywords European blackbirds; birds; Turdus merula; animals; melatonin; *Photoperiod
Abstract INTRODUCTION: Artificial light-at-night is known to affect a broad array of behaviours and physiological processes. In urbanized bird species, light-at-night advances important biological rhythms such as daily cycles of activity/rest and timing of reproduction, but our knowledge of the underlying physiological mechanisms is limited. Given its role as chronobiological signal, melatonin is a strong candidate for mediating the effects of light-at-night. RESULTS: We exposed urban and rural European blackbirds (Turdus merula) to two light treatments equal in photoperiod but with different light intensities at night. The control group was exposed to 0.0001 lux (almost darkness), while the experimental group was exposed to 0.3 lux at night, simulating conditions recorded previously on free-living urban blackbirds. We obtained diel profiles of plasma melatonin for all birds in summer (July) and winter (January), while simultaneously recording locomotor activity. Daily patterns of melatonin concentrations were clearly affected by light-at-night in both seasons. In winter, melatonin concentrations of light-at-night birds were lower in the early and late night than in those of birds kept in darkness. In summer, melatonin concentrations of the light-at-night birds were lower through all night compared to birds kept in darkness. Locomotor activity in light-at-night birds was overall higher than in control individuals, both during the day and at night, and it increased sharply before dawn. In winter, the amount of activity before dawn in the light-at-night group correlated with changes in melatonin from midnight to late night: the greater the decrease in melatonin, the greater the amount of pre-dawn activity. Urban and rural birds responded similarly to light-at-night with respect to melatonin, but differed in their behaviour, with rural birds showing more locomotor activity than urban counterparts. CONCLUSIONS: This study points to reduced melatonin release at night as a potential physiological mechanism underlying the advanced onset of morning activity of urbanized birds. Based on the pattern of melatonin secretion, we suggest that birds responded to light-at-night as if they were exposed to a longer day than birds kept under dark nights.
Address Department of Migration and Immuno-ecology, Max Planck Institute for Ornithology, Radolfzell, Germany. ddominoni@orn.mpg.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 1742-9994 ISBN Medium
Area Expedition Conference
Notes PMID:24090446; PMCID:PMC3850952 Approved no
Call Number IDA @ john @ Serial 41
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Author Kamrowski, R.L.; Limpus, C.; Jones, R.; Anderson, S.; Hamann, M.
Title Temporal changes in artificial light exposure of marine turtle nesting areas Type Journal Article
Year 2013 Publication Global Change Biology Abbreviated Journal (up) Glob Chang Biol
Volume 20 Issue 8 Pages 2437-2449
Keywords GIS analysis; artificial light; conservation planning; marine turtles; population resilience; temporal change
Abstract Artificial light at night poses a significant threat to multiple taxa across the globe. In coastal regions, artificial lighting close to marine turtle nesting beaches is disruptive to their breeding success. Prioritizing effective management of light pollution requires an understanding of how the light exposure of nesting areas changes over time in response to changing temporal and spatial distributions of coastal development. We analyzed multitemporal, satellite night-light data, in combination with linear mixed model analysis, to determine broadscale changes in artificial light exposure at Australian marine turtle nesting areas between 1993 and 2010. We found seven marine turtle management units (MU), from five species, have experienced significant increases in light exposure over time, with flatback turtles nesting in east Australia experiencing the fastest increases. The remaining 12 MUs showed no significant change in light exposure. Unchanging MUs included those previously identified as having high exposure to light pollution (located in western Australia and southern Queensland), indicating that turtles in these areas have been potentially exposed to high light levels since at least the early nineties. At a finer geographic scale (within-MU), nine MUs contained nesting areas with significant increases in light exposure. These nesting areas predominantly occurred close to heavily industrialized coastal areas, thus emphasizing the importance of rigorous light management in industry. Within all MUs, nesting areas existed where light levels were extremely low and/or had not significantly increased since 1993. With continued coastal development, nesting females may shift to these darker/unchanging 'buffer' areas in the future. This is valuable information that informs our understanding of the capacity and resilience of marine turtles faced with coastal development: an understanding that is essential for effective marine turtle conservation.
Address School of Earth and Environmental Sciences, James Cook University, Townsville, QLD, 4811, Australia
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 1354-1013 ISBN Medium
Area Expedition Conference
Notes PMID:24353164 Approved no
Call Number IDA @ john @ Serial 73
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Author Clark, G.F.; Stark, J.S.; Johnston, E.L.; Runcie, J.W.; Goldsworthy, P.M.; Raymond, B.; Riddle, M.J.
Title Light-driven tipping points in polar ecosystems Type Journal Article
Year 2013 Publication Global Change Biology Abbreviated Journal (up) Glob Chang Biol
Volume 19 Issue 12 Pages 3749-3761
Keywords Ecology; benthic; biodiversity; irradiance; macroalgae; marine ecology; polar; regime shift
Abstract Some ecosystems can undergo abrupt transformation in response to relatively small environmental change. Identifying imminent 'tipping points' is crucial for biodiversity conservation, particularly in the face of climate change. Here, we describe a tipping point mechanism likely to induce widespread regime shifts in polar ecosystems. Seasonal snow and ice-cover periodically block sunlight reaching polar ecosystems, but the effect of this on annual light depends critically on the timing of cover within the annual solar cycle. At high latitudes, sunlight is strongly seasonal, and ice-free days around the summer solstice receive orders of magnitude more light than those in winter. Early melt that brings the date of ice-loss closer to midsummer will cause an exponential increase in the amount of sunlight reaching some ecosystems per year. This is likely to drive ecological tipping points in which primary producers (plants and algae) flourish and out-compete dark-adapted communities. We demonstrate this principle on Antarctic shallow seabed ecosystems, which our data suggest are sensitive to small changes in the timing of sea-ice loss. Algae respond to light thresholds that are easily exceeded by a slight reduction in sea-ice duration. Earlier sea-ice loss is likely to cause extensive regime shifts in which endemic shallow-water invertebrate communities are replaced by algae, reducing coastal biodiversity and fundamentally changing ecosystem functioning. Modeling shows that recent changes in ice and snow cover have already transformed annual light budgets in large areas of the Arctic and Antarctic, and both aquatic and terrestrial ecosystems are likely to experience further significant change in light. The interaction between ice-loss and solar irradiance renders polar ecosystems acutely vulnerable to abrupt ecosystem change, as light-driven tipping points are readily breached by relatively slight shifts in the timing of snow and ice-loss.
Address School of Biological, Earth and Environmental Science, University of New South Wales, Sydney, NSW, 2052, Australia
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 1354-1013 ISBN Medium
Area Expedition Conference
Notes PMID:23893603 Approved no
Call Number LoNNe @ kagoburian @ Serial 850
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Author Jackett, M.; Frith, W.
Title Quantifying the impact of road lighting on road safety -- A New Zealand Study Type Journal Article
Year 2013 Publication IATSS Research Abbreviated Journal (up) IATSS Research
Volume 36 Issue 2 Pages 139-145
Keywords Lighting; roadway lighting; road safety; traffic safety; public safety
Abstract It is well known from the literature that road lighting has significant safety benefits. The NZTA Economic Evaluation Manual (EEM) quotes a 35% reduction in crashes as the effect of upgrading or improving lighting where lighting is poor.

However, no well-established dose–response relationship to lighting parameters exists from which one can deduce benchmark levels of lighting for safety.

This study looked at a sample of street lighting installations spread over the urban areas of nine territorial local authorities. Standard street lighting parameters were measured in the field using a variety of instruments including illuminance meter, luminance meter and digital camera. Field measurements were related to the ratio of night-time to day time crashes as a measure of night time safety vis-a-vis daytime safety.

A statistically significant dose–response relationship was found between average road luminance and safety across all traffic volume groups, with an indication that the relationship may be stronger where more serious crashes are involved.

Threshold increment was also a significant variable but not so longitudinal uniformity or overall uniformity.

The results related to luminance will allow practitioners to better estimate the safety benefits of different levels of lighting resulting in better targeting of expenditure.
Address Jackett Consulting, Lower Hutt, New Zealand; jackett(at)paradise.net.nz
Corporate Author Thesis
Publisher Elsevier Place of Publication Editor
Language English Summary Language English Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0386-1112 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number LoNNe @ kagoburian @ Serial 638
Permanent link to this record