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Author Bará, S.; Escofet, J.
Title On lamps, walls, and eyes: The spectral radiance field and the evaluation of light pollution indoors Type Journal Article
Year 2018 Publication Journal of Quantitative Spectroscopy and Radiative Transfer Abbreviated Journal J of Quant Spect and Rad Trans
Volume 205 Issue Pages 267-277
Keywords Instrumentation; Light pollution; Artificial light at night; Light field; Radiance field; Radiometry; Photometry
Abstract Light plays a key role in the regulation of different physiological processes, through several visual and non-visual retinal phototransduction channels whose basic features are being unveiled by recent research. The growing body of evidence on the significance of these effects has sparked a renewed interest in the determination of the light field at the entrance pupil of the eye in indoor spaces. Since photic interactions are strongly wavelength-dependent, a significant effort is being devoted to assess the relative merits of the spectra of the different types of light sources available for use at home and in the workplace. The spectral content of the light reaching the observer eyes in indoor spaces, however, does not depend exclusively on the sources: it is partially modulated by the spectral reflectance of the walls and surrounding surfaces, through the multiple reflections of the light beams along all possible paths from the source to the observer. This modulation can modify significantly the non-visual photic inputs that would be produced by the lamps alone, and opens the way for controlling—to a certain extent—the subject's exposure to different regions of the optical spectrum. In this work we evaluate the expected magnitude of this effect and we show that, for factorizable sources, the spectral modulation can be conveniently described in terms of a set of effective filter-like functions that provide useful insights for lighting design and light pollution assessment. The radiance field also provides a suitable bridge between indoor and outdoor light pollution studies.
Address Área de Óptica, Departamento de Física Aplicada, Universidade de Santiago de Compostela, Santiago de Compostela, Galicia, Spain; salva.bara(at)usc.es
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 0022-4073 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial (down) 2163
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Author Wood, J.M.; Isoardi, G.; Black, A.; Cowling, I.
Title Night-time driving visibility associated with LED streetlight dimming Type Journal Article
Year 2018 Publication Accident; Analysis and Prevention Abbreviated Journal Accid Anal Prev
Volume 121 Issue Pages 295-300
Keywords Public Safety
Abstract New LED streetlighting designs and dimming are being introduced worldwide, however, while their cost savings are well established, their impact on driving performance has received little attention. This study investigated the effect of streetlight dimming on night-time driving performance. Participants included 14 licensed drivers (mean age 34.2 +/- 4.9 years, range 27-40 years) who drove an instrumented vehicle around a closed circuit at night. Six LED streetlights were positioned along a 250 m, straight section and their light output varied between laps (dimming levels of 25%, 50%, 75% and 100% of maximum output; L25, L50, L75 and L100 respectively; at 100% average road surface luminance of 1.14 cd/m(2)). Driving tasks involved recognition distances and reaction times to a low contrast, moving target and a pedestrian walking at the roadside. Participants drove at an average driving speed of 55 km/hr in the streetlight zone. Streetlight dimming significantly delayed driver reaction times to the moving target (F3,13.06 = 6.404; p = 0.007); with an average 0.4 s delay in reaction times under L25 compared to L100, (estimated reduction in recognition distances of 6 m). Pedestrian recognition distances were significantly shorter under dimmed streetlight levels (F3,12.75 = 8.27; p = 0.003); average pedestrian recognition distances were 15 m shorter under L25 compared to L100, and 11 m shorter under L50 compared to L100. These data suggest that streetlight dimming impacts on driver visibility but it is unclear how these differences impact on safety; future studies are required to inform decisions on safe dimming levels for road networks.
Address School of Chemistry, Physics and Mechanical Engineering, Faculty of Science and Engineering Faculty, Queensland University of Technology, Brisbane, Queensland, 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 0001-4575 ISBN Medium
Area Expedition Conference
Notes PMID:30317014 Approved no
Call Number GFZ @ kyba @ Serial (down) 2160
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Author Fotios, S.; Monteiro, A.L.; Uttley, J.
Title Evaluation of pedestrian reassurance gained by higher illuminances in residential streets using the day–dark approach Type Journal Article
Year 2018 Publication Lighting Research & Technology Abbreviated Journal Lighting Research & Technology
Volume in press Issue Pages
Keywords Vision; Psychology; Security
Abstract A field study was conducted to investigate how changes in the illuminance affect pedestrian reassurance when walking after dark in an urban location. The field study was conducted in daytime and after dark in order to employ the day–dark approach to analysis of optimal lighting. The results suggest that minimum illuminance is a better predictor of reassurance than is mean illuminance. For a day–dark difference of 0.5 units on a 6-point response scale, the results suggest a minimum horizontal illuminance of approximately 2.0 lux.
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 1477-1535 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial (down) 2159
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Author Stern, M.; Broja, M.; Sansone, R.; Grone, M.; Skene, S.S.; Liebmann, J.; Suschek, C.V.; Born, M.; Kelm, M.; Heiss, C.
Title Blue light exposure decreases systolic blood pressure, arterial stiffness, and improves endothelial function in humans Type Journal Article
Year 2018 Publication European Journal of Preventive Cardiology Abbreviated Journal Eur J Prev Cardiol
Volume 25 Issue 17 Pages 1875-1883
Keywords Human Health; Blue light; blood pressure; endothelial function; forearm blood flow; pulse wave velocity
Abstract AIMS: Previous studies have shown that ultraviolet light can lead to the release of nitric oxide from the skin and decrease blood pressure. In contrast to visible light the local application of ultraviolet light bears a cancerogenic risk. Here, we investigated whether whole body exposure to visible blue light can also decrease blood pressure and increase endothelial function in healthy subjects. METHODS: In a randomised crossover study, 14 healthy male subjects were exposed on 2 days to monochromatic blue light or blue light with a filter foil (control light) over 30 minutes. We measured blood pressure (primary endpoint), heart rate, forearm vascular resistance, forearm blood flow, endothelial function (flow-mediated dilation), pulse wave velocity and plasma nitric oxide species, nitrite and nitroso compounds (secondary endpoints) during and up to 2 hours after exposure. RESULTS: Blue light exposure significantly decreased systolic blood pressure and increased heart rate as compared to control. In parallel, blue light significantly increased forearm blood flow, flow-mediated dilation, circulating nitric oxide species and nitroso compounds while it decreased forearm vascular resistance and pulse wave velocity. CONCLUSION: Whole body irradiation with visible blue light at real world doses improves blood pressure, endothelial function and arterial stiffness by nitric oxide released from photolabile intracutanous nitric oxide metabolites into circulating blood.
Address Department of Clinical and Experimental Medicine, Faculty of Health and Medical Sciences, University of Surrey, Stag Hill, Guildford GU2 7XH, UK. Email: c.heiss(at)
Corporate Author Thesis
Publisher SAGE Place of Publication Editor
Language English Summary Language English Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2047-4873 ISBN Medium
Area Expedition Conference
Notes PMID:30196723 Approved no
Call Number IDA @ john @ Serial (down) 2157
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Author Shor, E.; Potavskaya, R.; Kurtz, A.; Paik, I.; Huq, E.; Green, R.
Title PIF-mediated sucrose regulation of the circadian oscillator is light quality and temperature dependent Type Journal Article
Year 2018 Publication Genes Abbreviated Journal Genes (Basel)
Volume 9 Issue 12 Pages
Keywords Plants
Abstract Studies are increasingly showing that metabolic and circadian (~24 h) pathways are strongly interconnected, with the circadian system regulating the metabolic state of the cell, and metabolic products feeding back to entrain the oscillator. In plants, probably the most significant impact of the circadian system on metabolism is in its reciprocal regulation of photosynthesis; however, the pathways by which this occurs are still poorly understood. We have previously shown that members of the basic helix-loop-helix (bHLH) transcription factor PHYTOCHROME INTERACTING FACTOR (PIF) family are involved in the photosynthate entrainment of the circadian oscillator. In this paper, using Arabidopsis mutants and overexpression lines, we examine how temperature and light quality affect PIF-mediated sucrose signaling to the oscillator and examine the contributions of individual PIF members. Our results also show that the quality of light is important for PIF signaling, with red and blue lights having the opposite effects, and that temperature affects PIF-mediated sucrose signaling. We propose the light sensitivity of PIF-mediated sucrose entrainment of the oscillator may be important in enabling plants to distinguish between sucrose produced de novo from photosynthesis during the day and the sucrose products of starch degradation at the end of the night.
Address Department of Plant and Environmental Sciences, Institute for Life Sciences, Edmond J. Safra Campus, Givat Ram, Hebrew University, Jerusalem 91904, Israel. rgreen@mail.huji.ac.il
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 2073-4425 ISBN Medium
Area Expedition Conference
Notes PMID:30551669; PMCID:PMC6316277 Approved no
Call Number GFZ @ kyba @ Serial (down) 2155
Permanent link to this record