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Author Kocifaj, M.; Solano Lamphar, H.A.
Title Angular Emission Function of a City and Skyglow Modeling: A Critical Perspective Type Journal Article
Year 2016 Publication Publications of the Astronomical Society of the Pacific Abbreviated Journal Pasp
Volume 128 Issue 970 Pages (down) 124001
Keywords Skyglow
Abstract The radiative transfer equation (RTE) is a common approach to solving the transfer of electromagnetic energy in heterogeneous disperse media, such as atmospheric environment. One-dimensional RTE is a linear boundary value problem that is well suited to plane-parallel atmosphere with no diffuse intensity entering the top of the atmosphere. In nighttime regime, the ground-based light sources illuminate the atmosphere at its bottom interface. However, the light-pollution models conventionally use radiant intensity function rather than radiance. This might potentially result in a number of misconceptions. We focused on similarities and fundamental differences between both functions and clarified distinct consequences for the modeling of skyglow from finite-sized and semi-infinite light-emitting flat surfaces. Minimum requirements to be fulfilled by a City Emission Function (CEF) are formulated to ensure a successful solution of standard and inverse problems. It has been shown that the horizon radiance of a flat surface emitting in accordance with Garstang's function (GEF) would exceed any limit, meaning that the GEF is not an appropriate tool to model skyglow from distant sources. We developed two alternative CEFs to remedy this problem through correction of direct upward emissions; the most important strengths of the modified CEFs are detailed in this paper. Numerical experiments on sky luminance under well-posed and ill-posed boundary conditions were made for two extreme uplight fractions (F) and for three discrete distances from the city edge. The errors induced by replacing radiance with radiant intensity function in the RTE are generally low (15%–30%) if F is as large as 0.15, but alteration of the luminance may range over 1–3 orders of magnitude if F approaches zero. In the latter case, the error margin can increase by a factor of 10–100 or even 1000, even if the angular structure of luminance patterns suffers only weak changes. This is why such a shift in luminance magnitudes can be mistakenly interpreted as the effect of inaccurate estimate of lumens per head of the population rather than the effect of cosine distortion due to ill-posed inputs to the RTE. For that reason, a thorough revision (and/or remediation) of theoretical and computational models is suggested.
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 0004-6280 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number LoNNe @ kyba @ Serial 1564
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Author Szaz, D.; Horvath, G.; Barta, A.; Robertson, B.A.; Farkas, A.; Egri, A.; Tarjanyi, N.; Racz, G.; Kriska, G.
Title Lamp-Lit Bridges as Dual Light-Traps for the Night-Swarming Mayfly, Ephoron virgo: Interaction of Polarized and Unpolarized Light Pollution Type Journal Article
Year 2015 Publication PloS one Abbreviated Journal PLoS One
Volume 10 Issue 3 Pages (down) e0121194
Keywords Animals
Abstract Ecological photopollution created by artificial night lighting can alter animal behavior and lead to population declines and biodiversity loss. Polarized light pollution is a second type of photopollution that triggers water-seeking insects to ovisposit on smooth and dark man-made objects, because they simulate the polarization signatures of natural water bodies. We document a case study of the interaction of these two forms of photopollution by conducting observations and experiments near a lamp-lit bridge over the river Danube that attracts mass swarms of the mayfly Ephoron virgo away from the river to oviposit on the asphalt road of the bridge. Millions of mayflies swarmed near bridge-lights for two weeks. We found these swarms to be composed of 99% adult females performing their upstream compensatory flight and were attracted upward toward unpolarized bridge-lamp light, and away from the horizontally polarized light trail of the river. Imaging polarimetry confirmed that the asphalt surface of the bridge was strongly and horizontally polarized, providing a supernormal ovipositional cue to Ephoron virgo, while other parts of the bridge were poor polarizers of lamplight. Collectively, we confirm that Ephoron virgo is independently attracted to both unpolarized and polarized light sources, that both types of photopollution are being produced at the bridge, and that spatial patterns of swarming and oviposition are consistent with evolved behaviors being triggered maladaptively by these two types of light pollution. We suggest solutions to bridge and lighting design that should prevent or mitigate the impacts of such scenarios in the future. The detrimental impacts of such scenarios may extend beyond Ephoron virgo.
Address Danube Research Institute, Centre for Ecological Research, Hungarian Academy of Sciences, Budapest, Hungary; Group for Methodology in Biology Teaching, Biological Institute, Eotvos University, Budapest, Hungary
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 1932-6203 ISBN Medium
Area Expedition Conference
Notes PMID:25815748 Approved no
Call Number LoNNe @ christopher.kyba @ Serial 1145
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Author Russart, K.L.G.; Chbeir, S.A.; Nelson, R.J.; Magalang, U.J.
Title Light at night exacerbates metabolic dysfunction in a polygenic mouse model of type 2 diabetes mellitus Type Journal Article
Year 2019 Publication Life Sciences Abbreviated Journal Life Sci
Volume in press Issue Pages (down) 116574
Keywords Animals
Abstract AIMS: Electric lighting is beneficial to modern society; however, it is becoming apparent that light at night (LAN) is not without biological consequences. Several studies have reported negative effects of LAN on health and behavior in humans and nonhuman animals. Exposure of non-diabetic mice to dim LAN impairs glucose tolerance, whereas a return to dark nights (LD) reverses this impairment. We predicted that exposure to LAN would exacerbate the metabolic abnormalities in TALLYHO/JngJ (TH) mice, a polygenic model of type 2 diabetes mellitus (T2DM). MATERIALS AND METHODS: We exposed 7-week old male TH mice to either LD or LAN for 8-10weeks in two separate experiments. After 8weeks of light treatment, we conducted intraperitoneal glucose tolerance testing (ipGTT) followed by intraperitoneal insulin tolerance testing (ipITT). In Experiment 1, all mice were returned to LD for 4weeks, and ipITT was repeated. KEY FINDINGS: The major results of this study are i) LAN exposure for 8weeks exacerbates glucose intolerance and insulin resistance ii) the effects of LAN on insulin resistance are reversed upon return to LD, iii) LAN exposure results in a greater increase in body weight compared to LD exposure, iv) LAN increases the incidence of mice developing overt T2DM, and v) LAN exposure decreases survival of mice with T2DM. SIGNIFICANCE: In conclusion, LAN exacerbated metabolic abnormalities in a polygenic mouse model of T2DM, and these effects were reversed upon return to dark nights. The applicability of these findings to humans with T2DM needs to be determined.
Address Department of Neuroscience, The Ohio State University Wexner Medical Center, Columbus, OH 43210, USA; Department of Internal Medicine, The Ohio State University Wexner Medical Center, Columbus, OH 43210, 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 0024-3205 ISBN Medium
Area Expedition Conference
Notes PMID:31207311 Approved no
Call Number GFZ @ kyba @ Serial 2549
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Author Molcan, L.; Sutovska, H.; Okuliarova, M.; Senko, T.; Krskova, L.; Zeman, M.
Title Dim light at night attenuates circadian rhythms in the cardiovascular system and suppresses melatonin in rats Type Journal Article
Year 2019 Publication Life Sciences Abbreviated Journal Life Sci
Volume 231 Issue Pages (down) 116568
Keywords Animals
Abstract AIMS: Cardiovascular parameters exhibit significant 24-h variability, which is coordinated by the suprachiasmatic nucleus (SCN), and light/dark cycles control SCN activity. We aimed to study the effects of light at night (ALAN; 1-2lx) on cardiovascular system control in normotensive rats. MAIN METHODS: Heart rate (HR) and blood pressure (BP) were measured by telemetry during five weeks of ALAN exposure. From beat-to-beat telemetry data, we evaluated spontaneous baroreflex sensitivity (sBRS). After 2 (A2) and 5 (A5) weeks of ALAN, plasma melatonin concentrations and the response of BP and HR to norepinephrine administration were measured. The expression of endothelial nitric oxide synthase (eNOS) and endothelin-1 was determined in the aorta. Spontaneous exploratory behaviour was evaluated in an open-field test. KEY FINDINGS: ALAN significantly suppressed the 24-h variability in the HR, BP, and sBRS after A2, although the parameters were partially restored after A5. The daily variability in the BP response to norepinephrine was reduced after A2 and restored after A5. ALAN increased the BP response to norepinephrine compared to the control after A5. Increased eNOS expression was found in arteries after A2 but not A5. Endothelin-1 expression was not affected by ALAN. Plasma melatonin levels were suppressed after A2 and A5. Spontaneous exploratory behaviour was reduced. SIGNIFICANCE: ALAN decreased plasma melatonin and the 24-h variability in the haemodynamic parameters and increased the BP response to norepinephrine. A low intensity ALAN can suppress circadian control of the cardiovascular system with negative consequences on the anticipation of a load.
Address Department of Animal Physiology and Ethology, Faculty of Natural Sciences, Comenius University, Bratislava, Slovakia
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 0024-3205 ISBN Medium
Area Expedition Conference
Notes PMID:31202842 Approved no
Call Number GFZ @ kyba @ Serial 2548
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Author Navarro, Johanna Y.; Lahti, David C.
Title Light Dulls and Darkens Bird Eggs Type Journal Article
Year 2014 Publication PloS one Abbreviated Journal
Volume 9 Issue 12 Pages (down) e116112
Keywords aanimals; birds; eggshell; color
Abstract Although egg color is generally consistent within individual birds and robust to environmental variation, recent evidence suggests a degree of susceptibility to environmental perturbation or modulation of egg color. Most of this variation manifests via the physiology of the laying female, but some direct impacts of the environment on laid eggs have also been discovered. Here we test whether light changes bird egg color and we quantify its effect, by subjecting variable blue-green eggs of Rüppell's weaver (Ploceus galbula) to a broad-spectrum light source under laboratory conditions, and measuring egg reflectance every few hours. Eggshells gradually decreased in reflectance across the entire measured wavelength spectrum of 250–800 nm. Reflectance peaks were disproportionately affected, such that the height decreased of both the blue-green peak and the smaller UV peak typical of blue-green eggs. The reflectance of lighter eggs was affected slightly more than that of darker eggs. These changes are similar to previous results for changes over long periods of time in darkness, suggesting that light might hasten the same process of pigment degradation that proceeds even without light. Comparison between the experimental light source and both sunlight and typical artificial lighting situations raises the possibility that significant color change might occur during incubation in some birds, but indicates that eggshell illumination in museums for short periods of study is unlikely to affect their color to a detectable extent. Additional research should be performed on eggs of other species and in other light environments, with an eye to an eventual generalized model of the effect of light on eggshell color.
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
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Area Expedition Conference
Notes Approved no
Call Number LoNNe @ schroer @ Serial 1597
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