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Author Mpakairi, K.S.; Muvengwi, J.
Title Night-time lights and their influence on summer night land surface temperature in two urban cities of Zimbabwe: A geospatial perspective Type Journal Article
Year 2019 Publication Urban Climate Abbreviated Journal Urban Climate
Volume 29 Issue Pages (down) 100468
Keywords Remote Sensing
Abstract Owing to the developments that exist in urban landscapes, urban areas experience climates that are different from their surroundings even when in the same climatic region. This is a prominent phenomenon in most urban areas and is commonly known as Surface Urban Heat Island (SUHI). An understanding of some of the drivers of SUHI is imperative for cities worldwide if they endeavor to suppress the socio-economic mishaps related to extremely high UHI. In this study, we sought to explain the drivers of SUHI in two developing cities in Zimbabwe using remote sensing data. We do this through the use of a classification and regression model. The model used climate, land descriptors and anthropogenic activity data as predictor variables against summer night land surface temperature. Using the coefficient of determination (R2) and the root mean square error (RMSE) for evaluation, modelled SUHI was strongly related to actual SUHI. We also found out that night-time lights, a proxy of anthropogenic activity, contributed more to summer night surface urban heat island as compared to other variables used in the study. This study adds more knowledge on the likely drivers of UHI for southern African cities. By identifying SUHI drivers in urban cities, it is plausible to formulate policies or initiatives that regulate extreme summer night SUHI.
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Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2212-0955 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 2497
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Author Nelson, J.A.; Bugbee, B.
Title Economic analysis of greenhouse lighting: light emitting diodes vs. high intensity discharge fixtures Type Journal Article
Year 2014 Publication PloS one Abbreviated Journal PLoS One
Volume 9 Issue 6 Pages (down) e99010
Keywords Plants
Abstract Lighting technologies for plant growth are improving rapidly, providing numerous options for supplemental lighting in greenhouses. Here we report the photosynthetic (400-700 nm) photon efficiency and photon distribution pattern of two double-ended HPS fixtures, five mogul-base HPS fixtures, ten LED fixtures, three ceramic metal halide fixtures, and two fluorescent fixtures. The two most efficient LED and the two most efficient double-ended HPS fixtures had nearly identical efficiencies at 1.66 to 1.70 micromoles per joule. These four fixtures represent a dramatic improvement over the 1.02 micromoles per joule efficiency of the mogul-base HPS fixtures that are in common use. The best ceramic metal halide and fluorescent fixtures had efficiencies of 1.46 and 0.95 micromoles per joule, respectively. We also calculated the initial capital cost of fixtures per photon delivered and determined that LED fixtures cost five to ten times more than HPS fixtures. The five-year electric plus fixture cost per mole of photons is thus 2.3 times higher for LED fixtures, due to high capital costs. Compared to electric costs, our analysis indicates that the long-term maintenance costs are small for both technologies. If widely spaced benches are a necessary part of a production system, the unique ability of LED fixtures to efficiently focus photons on specific areas can be used to improve the photon capture by plant canopies. Our analysis demonstrates, however, that the cost per photon delivered is higher in these systems, regardless of fixture category. The lowest lighting system costs are realized when an efficient fixture is coupled with effective canopy photon capture.
Address Crop Physiology Laboratory, Department of Plant Soils and Climate, Utah State University, Logan, Utah, United States of America
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:24905835; PMCID:PMC4048233 Approved no
Call Number GFZ @ kyba @ Serial 2233
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Author Huss, A.; van Wel, L.; Bogaards, L.; Vrijkotte, T.; Wolf, L.; Hoek, G.; Vermeulen, R.
Title Shedding Some Light in the Dark-A Comparison of Personal Measurements with Satellite-Based Estimates of Exposure to Light at Night among Children in the Netherlands Type Journal Article
Year 2019 Publication Environmental Health Perspectives Abbreviated Journal Environ Health Perspect
Volume 127 Issue 6 Pages (down) 67001
Keywords Human Health; Remote Sensing
Abstract BACKGROUND: Exposure to light at night (LAN) can perturb the biological clock and affect sleep and health. Previous epidemiological studies have evaluated LAN levels measured by satellites, but the validity of this measure as a proxy for personal LAN exposure is unclear. In addition, outdoor satellite-measured LAN levels are higher in urban environments, which means that this measure could potentially represent a proxy for other, likely urban, environmental exposures. OBJECTIVES: We evaluated correlations of satellite-assessed LAN with measured bedroom light levels and explored correlations with other environmental exposures, in particular, air pollution, green space, and area-level socioeconomic position (SEP). METHODS: We compared satellite measurements with evening and nighttime bedroom measurements of illuminance (in units of lux) for 256 children, and we evaluated correlations between satellite-based measures and other urban exposures such as air pollution, area-level SEP, and surrounding green space for 3,021 children. RESULTS: Satellite-measured LAN levels (nanowatts per centimeter squared per steradian) were not correlated with measured evening or nighttime lux levels [Spearman correlation coefficients ([Formula: see text]) [Formula: see text] to 0.04]. There was a weak correlation with measurements during the darkest time period if parents and their children reported that outdoor light sometimes or usually influenced indoor light levels ([Formula: see text], [Formula: see text]). In contrast, satellite-measured LAN levels were correlated with air pollution ([Formula: see text] with [Formula: see text], [Formula: see text] with [Formula: see text]), and surrounding green space ([Formula: see text] for green space within [Formula: see text] of the home). A weak correlation with area-level SEP was also observed ([Formula: see text]). CONCLUSIONS: Outdoor satellite-assessed outdoor LAN exposure levels were correlated with urban environmental exposures, but they were not a good proxy for indoor evening or nighttime personal exposure as measured in our study population of 12-y-old children. Studies planning to evaluate potential risks from LAN should consider such modifying factors as curtains and indoor lighting and the use of electronic devices and should include performing indoor or personal measurements to validate any exposure proxies. The moderate-to-strong correlation of outdoor LAN with other environmental exposures should be accounted for in epidemiological investigations. https://doi.org/10.1289/EHP3431.
Address 4 Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht , Utrecht, Netherlands
Corporate Author Thesis
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Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0091-6765 ISBN Medium
Area Expedition Conference
Notes PMID:31157976 Approved no
Call Number GFZ @ kyba @ Serial 2532
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Author Kim, H.-S.; Lee, Y.H.
Title Correlation Analysis of Image Reproduction and Display Color Temperature Change to Prevent Sleep Disorder Type Journal Article
Year 2019 Publication IEEE Access Abbreviated Journal IEEE Access
Volume 7 Issue Pages (down) 59091-59099
Keywords Human Health
Abstract This paper aims to determine the effect of the smartphone warm color temperature functionthat relieves display’s HEVL (high-energy visible light and short wavelength series blue light), which isknown to cause suppression of melatonin secretion on actual image reproduction quality. For this study,the author of this paper measured the display based on the color difference in 26 sampling colors. It was foundthat for correlated color temperature (CCT) of 4000 K or less, the color difference rose sharply, centeringaround red and green. In hardware or software, a low CCT was realized by reducing the output centered onblue and green, but in actual color quality, a problem arose in the red and green channels. As far as tonegradation is concerned,1E increased for CCT of 4500 K or less while the accuracy of the shadow detail wasreduced. With regard to color gamut reproduction, for the coverage of sRGB color space, the color gamutbecame narrow for CCT of 5500 K or less, and for volume, the color gamut became narrow sharply for CCTof 4000 K. It was found that the maximum CCT changes to prevent a decline in melatonin secretion at alevel of minimizing the degradation of image quality is 4000–4500 K.
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Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2169-3536 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 2500
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Author Zhang, Z.; Wang, H.-J.; Wang, D.-R.; Qu, W.-M.; Huang, Z.-L.
Title Red light at intensities above 10 lx alters sleep-wake behavior in mice Type Journal Article
Year 2017 Publication Light, Science & Applications Abbreviated Journal Light Sci Appl
Volume 6 Issue 5 Pages (down) e16231
Keywords Animals
Abstract Sleep is regulated by two mechanisms: the homeostatic process and the circadian clock. Light affects sleep and alertness by entraining the circadian clock, and acutely inducing sleep/alertness, in a manner mediated by intrinsically photosensitive retinal ganglion cells. Because intrinsically photosensitive retinal ganglion cells are believed to be minimally sensitive to red light, which is widely used for illumination to reduce the photic disturbance to nocturnal animals during the dark phase. However, the appropriate intensity of the red light is unknown. In the present study, we recorded electroencephalograms and electromyograms of freely moving mice to investigate the effects of red light emitted by light-emitting diodes at different intensities and for different durations on the sleep-wake behavior of mice. White light was used as a control. Unexpectedly, red light exerted potent sleep-inducing effects and changed the sleep architecture in terms of the duration and number of sleep episodes, the stage transition, and the EEG power density when the intensity was >20 lx. Subsequently, we lowered the light intensity and demonstrated that red light at or below 10 lx did not affect sleep-wake behavior. White light markedly induced sleep and disrupted sleep architecture even at an intensity as low as 10 lx. Our findings highlight the importance of limiting the intensity of red light (10 lx) to avoid optical influence in nocturnal behavioral experiments, particularly in the field of sleep and circadian research.
Address Institutes of Brain Science and Collaborative Innovation Center for Brain Science, Department of Pharmacology, School of Basic Medical Sciences, State Key Laboratory of Medical Neurobiology and Shanghai Key Laboratory of Clinical Geriatric Medicine, Shanghai Medical College, Fudan University, Shanghai 200032, China
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 2047-7538 ISBN Medium
Area Expedition Conference
Notes PMID:30167247; PMCID:PMC6062196 Approved no
Call Number GFZ @ kyba @ Serial 2463
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