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Author Garstang, R. H.
Title Limiting visual magnitude and night sky brightness Type Journal Article
Year (up) 2000 Publication Memorie della Società Astronomia Italiana Abbreviated Journal
Volume 71 Issue Pages
Keywords Skyglow
Abstract We review the theory of visual thresholds and applications to the limiting magnitude of a telescope and of the eyes, based on Schaefers's model with minor improvements. We apply out formulation to the Yerkes Observatory refractor and to naked eye observations at Mount Wilson Observatory. We reanalyze Bowen's telescopic observations at Mount Wilson by his approximate method and by our more elaborate theory. An extension of his method leads to a determination of the night sky brightness of the visual activity of the observer is assumed to be average. Our more elaborate method allows a determination of the sky brightness, the visual acuity of the observer, and the average seeing during the observations.
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Call Number IDA @ intern @ Serial 2623
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Author Elvidge, C.D.; Imhoff, M.L.; Baugh, K.E.; Hobson, V.R.; Nelson, I.; Safran, J.; Dietz, J.B.; Tuttle, B.T.
Title Night-time lights of the world: 1994–1995 Type Journal Article
Year (up) 2001 Publication ISPRS Journal of Photogrammetry and Remote Sensing Abbreviated Journal ISPRS Journal of Photogrammetry and Remote Sensing
Volume 56 Issue 2 Pages 81-99
Keywords Remote Sensing
Abstract The Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS) has a unique low-light imaging capability developed for the detection of clouds using moonlight. In addition to moonlit clouds, the OLS also detects lights from human settlements, fires, gas flares, heavily lit fishing boats, lightning and the aurora. By analysing the location, frequency, and appearance of lights observed in an image time series, it is possible to distinguish four primary types of lights present at the earth's surface: human settlements, gas flares, fires, and fishing boats. We have produced a global map of the four types of light sources as observed during a 6-month time period in 1994–1995. We review a number of environmental applications that have been developed or proposed based on the night-time light data. We examine the relationship between area of lighting, population, economic activity, electric power consumption, and energy related carbon emissions for 200 nations, representing 99% of the world's population.
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ISSN 0924-2716 ISBN Medium
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Notes Approved no
Call Number GFZ @ kyba @ Serial 2009
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Author Sullivan, J.M.; Flannagan, M.J.
Title The role of ambient light level in fatal crashes: inferences from daylight saving time transitions Type Journal Article
Year (up) 2002 Publication Accident Analysis & Prevention Abbreviated Journal Accident Analysis & Prevention
Volume 34 Issue 4 Pages 487-498
Keywords Public Safety; Lighting
Abstract The purpose of this study was to estimate the size of the influence of ambient light level on fatal pedestrian and vehicle crashes in three scenarios. The scenarios were: fatal pedestrian crashes at intersections, fatal pedestrian crashes on dark rural roads, and fatal single-vehicle run-off-road crashes on dark, curved roads. Each scenario's sensitivity to light level was evaluated by comparing the number of fatal crashes across changes to and from daylight saving time, within daily time periods in which an abrupt change in light level occurs relative to official clock time. The analyses included 11 years of fatal crashes in the United States, between 1987 and 1997. Scenarios involving pedestrians were most sensitive to light level, in some cases showing up to seven times more risk at night over daytime. In contrast, single-vehicle run-off-road crashes showed little difference between light and dark time periods, suggesting factors other than light level play the dominant role in these crashes. These results are discussed in the context of the possible safety improvements offered by new developments in adaptive vehicle headlighting.
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ISSN 0001-4575 ISBN Medium
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Notes Approved no
Call Number GFZ @ kyba @ Serial 2126
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Author Sanotra, G.S.; Lund, J.D.; Vestergaard, K.S.
Title Influence of light-dark schedules and stocking density on behaviour, risk of leg problems and occurrence of chronic fear in broilers Type Journal Article
Year (up) 2002 Publication British Poultry Science Abbreviated Journal Br Poult Sci
Volume 43 Issue 3 Pages 344-354
Keywords Animals
Abstract 1. The aims of this study were to determine (1) the effect of light-dark schedules on the walking ability, the risk of tibial dyschondroplasia (TD) as well as the duration of tonic immobility (TI) reactions in commercial broiler flocks and (2) the effect of a daily dark period and reduced density on the behaviour of broiler chickens. 2. Experiment 1. Group 1 had a 2 to 8 h daily dark period from 2 to 26 d of age (light-dark programme A) at a stocking density of 28.4 chicks/m2. Group 2 had 8 h of darkness daily from 2 to 38 d of age (light-dark programme B) at 24 chicks/m2. The control group had 24 h continuous light at 28.4 chicks/m2. 3. Experiment 2. Behaviour was studied with and without a daily 8 h dark period and at high (30 chicks/m2) and low (18 chicks/m2) stocking densities. 4. Programme B reduced the prevalence of impaired walking ability, corresponding to gait score > 2, when compared with controls. The effect on walking ability corresponding to gait score > 0 approached significance. 5. Both light-dark programmes reduced the occurrence of TD. Programme B (combined with reduced stocking density), however, had the greater effect. 6. Both light-dark programmes reduced the duration of TI, compared with controls (mean = 426 s) Programme B resulted in a larger reduction (alpha = -156.9 s) than programme A (alpha = -117.0). 7. The proportions of chicks drinking, eating, pecking, scratching, standing and performing vertical wing-shakes increased--both when the 8 h dark period and the reduced stocking density were applied separately and in combination (experiment 2). 8. For all behaviours, except standing, the effect of the dark period was largest in broilers kept at the high stocking density (d 40).
Address Department of Animal Science and Animal Health, Division of Ethology and Health, Royal Veterinary and Agricultural University, Groennegaardsvej 8, DK-1870 Frederiksberg C, Copenhagen, Denmark. sgs@kvl.dk
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ISSN 0007-1668 ISBN Medium
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Notes PMID:12195793 Approved no
Call Number GFZ @ kyba @ Serial 2169
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Author Middleton, B.; Stone, B.M.; Arendt, J.
Title Human circadian phase in 12:12 h, 200:<8 lux and 1000:<8 lux light-dark cycles, without scheduled sleep or activity Type Journal Article
Year (up) 2002 Publication Neuroscience Letters Abbreviated Journal Neuroscience Letters
Volume 329 Issue 1 Pages 41-44
Keywords Human Health
Abstract The light levels required to maintain human circadian phase in the absence of other strong time cues are not defined. We investigated circadian phase in two groups of men, living in partial temporal isolation, exposed to 12 h:12 h light:dark cycles of: (A) 200:<8 lux, broad spectrum white light for 14 days; and (B) 1000:<8lux for 14 days. The rhythm variables measured were urinary 6-sulphatoxymelatonin, rectal temperature, activity and rest (actigraphy and sleep logs). In 200:<8 lux four/six individuals showed phase delays. Exposure to 1000:<8 lux appeared to maintain synchronisation of rest-activity to 24 h, but with a significant overall phase advance of 0.81 h in temperature. These observations suggest that domestic intensity light does not maintain phase without scheduled sleep/activity, possibly due to indirect effects on behaviour influencing light exposure.
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ISSN 0304-3940 ISBN Medium
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Notes Approved no
Call Number GFZ @ kyba @ Serial 2247
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