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Bailey, L.A.; Brigham, R.M.; Bohn, S.J.; Boyles, J.G.; Smit, B. |
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Title |
An experimental test of the allotonic frequency hypothesis to isolate the effects of light pollution on bat prey selection |
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Journal Article |
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Year |
2019 |
Publication |
Oecologia |
Abbreviated Journal |
Oecologia |
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Volume |
190 |
Issue |
2 |
Pages |
367–374 |
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Keywords |
Animals; Ecology; bats; moths; insects; mammals |
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Abstract |
Artificial lights may be altering interactions between bats and moth prey. According to the allotonic frequency hypothesis (AFH), eared moths are generally unavailable as prey for syntonic bats (i.e., bats that use echolocation frequencies between 20 and 50 kHz within the hearing range of eared moths) due to the moths' ability to detect syntonic bat echolocation. Syntonic bats therefore feed mainly on beetles, flies, true bugs, and non-eared moths. The AFH is expected to be violated around lights where eared moths are susceptible to exploitation by syntonic bats because moths' evasive strategies become less effective. The hypothesis has been tested to date almost exclusively in areas with permanent lighting, where the effects of lights on bat diets are confounded with other aspects of human habitat alteration. We undertook diet analysis in areas with short-term, localized artificial lighting to isolate the effects of artificial lighting and determine if syntonic and allotonic bats (i.e., bats that use echolocation frequencies outside the hearing range of eared moths) consumed more moths under conditions of artificial lights than in natural darkness. We found that syntonic bats increased their consumption of moth prey under experimentally lit conditions, likely owing to a reduction in the ability of eared moths to evade the bats. Eared moths may increase in diets of generalist syntonic bats foraging around artificial light sources, as opposed to allotonic species and syntonic species with a more specialized diet. |
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Department of Zoology and Entomology, Rhodes University, P.O. Box 94, Grahamstown, 6140, South Africa. b.smit@ru.ac.za |
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0029-8549 |
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PMID:31139944 |
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GFZ @ kyba @ |
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2511 |
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Author |
Bapary, M.A.J.; Takano, J.-I.; Soma, S.; Sankai, T. |
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Title |
Effect of blue LED light and antioxidants potential in a somatic cell |
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Journal Article |
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Year |
2019 |
Publication |
Cell Biology International |
Abbreviated Journal |
Cell Biol Int |
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Volume |
43 |
Issue |
11 |
Pages |
1296-1306 |
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Keywords |
Cells; Biology; LED; blue light; Antioxidants; cell death |
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Abstract |
Light is an indispensable part of routine laboratory works in which conventional light is generally used. Light-emitting diodes (LEDs) have come to replace the conventional light thus could be a potent target in biomedical studies. Since blue light is a major component of visible light wavelength, in this study, using a somatic cell from African green monkey kidney, we assessed the possible consequences of blue spectra of LED light in future animal experiments and proposed a potent mitigation against light induced damages. COS-7 cells were exposed to blue LED light (450 nm) and the growth and DNA damage were assessed at different exposure times. A higher suppression in cell growth and viability was observed under a longer period of blue LED light exposure. The number of apoptotic cells increased as light exposure time was prolonged. Reactive oxygen species generation was also elevated in accordance to the extension of light exposure times. A comparison to dark-maintained cells revealed that the upregulation of ROS by blue LED light plays a significant role in causing cellular dysfunction in DNA in a time-dependent manner. In turn, antioxidant treatment has shown to improve the cell growth and viability under blue LED light conditions. This indicates that antioxidants are potential against blue LED light-induced somatic cell damage. It is expected that this study will contribute to the understanding of the basic mechanism of somatic cell death under visible light and to maximize the beneficial use of LED light in future animal experiments. |
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Tsukuba Primate Research Center, National Institutes of Biomedical Innovation, Health and Nutrition, Ibaraki, Japan |
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1065-6995 |
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PMID:30958611 |
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GFZ @ kyba @ |
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2328 |
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Author |
Bará, S. |
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Title |
Naked-eye astronomy: optics of the starry night skies |
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Journal Article |
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Year |
2014 |
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Proc. SPIE 9289, 12th Education and Training in Optics and Photonics Conference, 2014 |
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Proc. SPIE 9289 |
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9289 |
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Society; light pollution |
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The world at night offers a wealth of stimuli and opportunities as a resource for Optics education, at all age levels and from any (formal, non formal or informal) perspective. The starry sky and the urban nightscape provide a unique combination of pointlike sources with extremely different emission spectra and brightness levels on a generally darker, locally homogeneous background. This fact, combined with the particular characteristics of the human visual system under mesopic and scotopic conditions, provides a perfect setting for experiencing first-hand different optical phenomena of increasing levels of complexity: from the eye's point spread function to the luminance contrast threshold for source detection, from basic diffraction patterns to the intricate irradiance fluctuations due to atmospheric turbulence. Looking at the nightscape is also a perfect occasion to raise awareness on the increasing levels of light pollution associated to the misuse of public and private artificial light at night, to promote a sustainable use of lighting, and to take part in worldwide citizen science campaigns. Last but not least, night sky observing activities can be planned and developed following a very flexible schedule, allowing individual students to carry them out from home and sharing the results in the classroom as well as organizing social events and night star parties with the active engagement of families and groups of the local community. This contribution describes these possibilities and introduces some of the free resources available to put them in practice. |
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Univ. de Santiago de Compostela, Spain; salva.bara@usc.es |
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SPIE |
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English |
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English |
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Call Number |
IDA @ john @ |
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1134 |
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Author |
Bará, S. |
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Title |
Light pollution and solid-state lighting: reducing the carbon dioxide footprint is not enough |
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Journal Article |
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Year |
2014 |
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Proc. SPIE 8785, 8th Iberoamerican Optics Meeting and 11th Latin American Meeting on Optics, Lasers, and Applications, 87852G, 2013 |
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Proc. SPIE 8785 |
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8785 |
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*Lighting; LED; light emitting diode; outdoor lighting; artificial light at night; lighting policy; solid-state lighting; blue light |
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Public and private lighting account for a relevant share of the overall electric power consumption worldwide. The pressing need of reducing the carbon dioxide emissions as well as of lowering the lumen•hour price tag has fostered the search for alternative lighting technologies to substitute for the incandescent and gas-discharge based lamps. The most successful approach to date, solid-state lighting, is already finding its way into the public lighting market, very often helped by substantial public investments and support. LED-based sources have distinct advantages: under controlled conditions their efficacy equals or surpasses that of conventional solutions, their small source size allows for an efficient collimation of the lightbeam (delivering the photons where they are actually needed and reducing lightspill on the surrounding areas), and they can be switched and/or dimmed on demand at very high rates, thus allowing for a tailored schedule of lighting. However, energy savings and carbon dioxide reduction are not the only crucial issues faced by present day lighting. A growing body of research has shown the significance of the spectral composition of light when it comes to assess the detrimental effects of artificial light-at-night (ALAN). The potential ALAN blueshift associated to the deployment of LED-based lighting systems has raised sensible concerns about its scientific, cultural, ecological and public health consequences, which can be further amplified if an increased light consumption is produced due to the rebound effect. This contribution addresses some of the challenges that these issues pose to the Optics and Photonics community. |
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Univ. de Santiago de Compostela, Spain; salva.bara@usc.es |
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SPIE |
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English |
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English |
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IDA @ john @ |
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1135 |
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Author |
Bará, S. |
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Title |
Anthropogenic disruption of the night sky darkness in urban and rural areas |
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Journal Article |
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Year |
2016 |
Publication |
Royal Society Open Science |
Abbreviated Journal |
R. Soc. open sci. |
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3 |
Issue |
10 |
Pages |
160541 |
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Keywords |
Skyglow |
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Abstract |
The growing emissions of artificial light to the atmosphere are producing, among other effects, a significant increase of the night sky brightness (NSB) above its expected natural values. A permanent sensor network has been deployed in Galicia (northwest of Iberian peninsula) to monitor the anthropogenic disruption of the night sky darkness in a countrywide area. The network is composed of 14 detectors integrated in automated weather stations of MeteoGalicia, the Galician public meteorological agency. Zenithal NSB readings are taken every minute and the results are openly available in real time for researchers, interested stakeholders and the public at large through a dedicated website. The measurements allow one to assess the extent of the loss of the natural night in urban, periurban, transition and dark rural sites, as well as its daily and monthly time courses. Two metrics are introduced here to characterize the disruption of the night darkness across the year: the significant magnitude (m1/3) and the moonlight modulation factor (γ). The significant magnitude shows that in clear and moonless nights the zenithal night sky in the analysed urban settings is typically 14–23 times brighter than expected from a nominal natural dark sky. This factor lies in the range 7–8 in periurban sites, 1.6–2.5 in transition regions and 0.8–1.6 in rural and mountain dark sky places. The presence of clouds in urban areas strongly enhances the amount of scattered light, easily reaching amplification factors in excess of 25, in comparison with the light scattered in the same places under clear sky conditions. The periodic NSB modulation due to the Moon, still clearly visible in transition and rural places, is barely notable at periurban locations and is practically lost at urban sites. |
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2054-5703 |
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LoNNe @ kyba @ |
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1544 |
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