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Author Small, C.; Elvidge, C.D.
Title Night on Earth: Mapping decadal changes of anthropogenic night light in Asia Type Journal Article
Year 2013 Publication International Journal of Applied Earth Observation and Geoinformation Abbreviated Journal International Journal of Applied Earth Observation and Geoinformation
Volume 22 Issue Pages 40-52
Keywords Urban; Night light; DMSP-OLS; Landsat; Zipf; Asia; India; China; Nightsat; remote sensing; light at night; satellite
Abstract The defense meteorological satellite program (DMSP) operational linescan system (OLS) sensors have imaged emitted light from Earth's surface since the 1970s. Temporal overlap in the missions of 5 OLS sensors allows for intercalibration of the annual composites over the past 19 years (Elvidge et al., 2009). The resulting image time series captures a spatiotemporal signature of the growth and evolution of lighted human settlements and development. We use empirical orthogonal function (EOF) analysis and the temporal feature space to characterize and quantify patterns of temporal change in stable night light brightness and spatial extent since 1992. Temporal EOF analysis provides a statistical basis for representing spatially abundant temporal patterns in the image time series as uncorrelated vectors of brightness as a function of time from 1992 to 2009. The variance partition of the eigenvalue spectrum combined with temporal structure of the EOFs and spatial structure of the PCs provides a basis for distinguishing between deterministic multi-year trends and stochastic year-to-year variance. The low order EOFs and principal components (PC) space together discriminate both earlier (1990s) and later (2000s) increases and decreases in brightness. Inverse transformation of these low order dimensions reduces stochastic variance sufficiently so that tri-temporal composites depict potentially deterministic decadal trends. The most pronounced changes occur in Asia. At critical brightness threshold we find an 18% increase in the number of spatially distinct lights and an 80% increase in lighted area in southern and eastern Asia between 1992 and 2009. During this time both China and India experienced a &#8764;20% increase in number of lights and a &#8764;270% increase in lighted area – although the timing of the increase is later in China than in India. Throughout Asia a variety of different patterns of brightness increase are apparent in tri-temporal brightness composites – as well as some conspicuous areas of apparently decreasing background luminance and, in many places, intermittent light suggesting development of infrastructure rather than persistently lighted development. Vicarious validation using higher resolution Landsat imagery verifies multiple phases of urban growth in several cities as well as the consistent presence of low DN (<&#8764;15) background luminance for many agricultural areas. Lights also allow us to quantify changes in the size distribution and connectedness of different intensities of development. Over a wide range of brightnesses, the size distributions of spatially contiguous lighted area are consistent with power laws with exponents near &#8722;1 as predicted by Zipf's Law for cities. However, the larger lighted segments are much larger than individual cities; they correspond to vast spatial networks of contiguous development (Small et al., 2011).
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ISSN 0303-2434 ISBN Medium (up)
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Notes Approved no
Call Number IDA @ john @ Serial 222
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Author Warrant, E.J.; Johnsen, S.
Title Vision and the light environment Type Journal Article
Year 2013 Publication Current Biology : CB Abbreviated Journal Curr Biol
Volume 23 Issue 22 Pages R990-4
Keywords photobiology; animals; physiology of vision; photodetection
Abstract Almost all animals, no matter how humble, possess eyes. Only those that live in total darkness, such as in a pitch-dark cave, may lack eyes entirely. Even at tremendous depths in the ocean — where the only lights that are ever seen are rare and fitful sparks of bioluminescence — most animals have eyes, and often surprisingly well-developed eyes. And despite their diversity (there are currently ten generally recognised optical types) all eyes have evolved in response to the remarkably varied light environments that are present in the habitats where animals live. Variations in the intensity of light, as well as in its direction, colour and dominant planes of polarisation, have all had dramatic effects on visual evolution. In the terrestrial habitats where we ourselves have most recently evolved, the light environment can vary quite markedly from day to night and from one location to another. In aquatic habitats, this variation can be orders of magnitude greater. Even though the ecologies and life histories of animals have played a major role in visual evolution, it is arguably the physical limitations imposed on photodetection by a given habitat and its light environment that have defined the basic selective pressures that have driven the evolution of eyes.
Address Department of Biology, University of Lund, Solvegatan 35, S-22362 Lund, Sweden. Electronic address: Eric.Warrant@biol.lu.se
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ISSN 0960-9822 ISBN Medium (up)
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Notes PMID:24262832 Approved no
Call Number IDA @ john @ Serial 235
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Author Ruger, M.; St Hilaire, M.A.; Brainard, G.C.; Khalsa, S.-B.S.; Kronauer, R.E.; Czeisler, C.A.; Lockley, S.W.
Title Human phase response curve to a single 6.5 h pulse of short-wavelength light Type Journal Article
Year 2013 Publication The Journal of Physiology Abbreviated Journal J Physiol
Volume 591 Issue Pt 1 Pages 353-363
Keywords Adolescent; Adult; Body Temperature; Circadian Rhythm/*physiology; Female; Humans; *Light; Male; Melatonin/physiology; Young Adult; blue light; melatonin; photic response; whort-wavelength
Abstract The photic resetting response of the human circadian pacemaker depends on the timing of exposure, and the direction and magnitude of the resulting shift is described by a phase response curve (PRC). Previous PRCs in humans have utilized high-intensity polychromatic white light. Given that the circadian photoreception system is maximally sensitive to short-wavelength visible light, the aim of the current study was to construct a PRC to blue (480 nm) light and compare it to a 10,000 lux white light PRC constructed previously using a similar protocol. Eighteen young healthy participants (18-30 years) were studied for 9-10 days in a time-free environment. The protocol included three baseline days followed by a constant routine (CR) to assess initial circadian phase. Following this CR, participants were exposed to a 6.5 h 480 nm light exposure (11.8 muW cm(-2), 11.2 lux) following mydriasis via a modified Ganzfeld dome. A second CR was conducted following the light exposure to re-assess circadian phase. Phase shifts were calculated from the difference in dim light melatonin onset (DLMO) between CRs. Exposure to 6.5 h of 480 nm light resets the circadian pacemaker according to a conventional type 1 PRC with fitted maximum delays and advances of -2.6 h and 1.3 h, respectively. The 480 nm PRC induced approximately 75% of the response of the 10,000 lux white light PRC. These results may contribute to a re-evaluation of dosing guidelines for clinical light therapy and the use of light as a fatigue countermeasure.
Address Circadian Physiology Program, Division of Sleep Medicine, Brigham and Women's Hospital, Harvard Medical School, 221 Longwood Avenue, Boston, MA 02115, USA. mrueger@rics.bwh.harvard.edu
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ISSN 0022-3751 ISBN Medium (up)
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Notes PMID:23090946; PMCID:PMC3630790 Approved no
Call Number IDA @ john @ Serial 239
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Author Dukic, T.; Ahlstrom, C.; Patten, C.; Kettwich, C.; Kircher, K.
Title Effects of electronic billboards on driver distraction Type Journal Article
Year 2013 Publication Traffic Injury Prevention Abbreviated Journal Traffic Inj Prev
Volume 14 Issue 5 Pages 469-476
Keywords Adult; Advertising as Topic/*methods; *Attention; Automobile Driving/*psychology; Eye Movements; Humans; Middle Aged; Psychomotor Performance; Sweden; Time Factors
Abstract OBJECTIVE: There is an increase in electronic advertising billboards along major roads, which may cause driver distraction due to the highly conspicuous design of the electronic billboards. Yet limited research on the impact of electronic billboards on driving performance and driver behavior is available. The Swedish Transport Administration recently approved the installation of 12 electronic billboards for a trial period along a 3-lane motorway with heavy traffic running through central Stockholm, Sweden. The aim of this study was to evaluate the effect of these electronic billboards on visual behavior and driving performance. METHOD: A total of 41 drivers were recruited to drive an instrumented vehicle passing 4 of the electronic billboards during day and night conditions. A driver was considered visually distracted when looking at a billboard continuously for more than 2 s or if the driver looked away from the road for a high percentage of time. Dependent variables were eye-tracking measures and driving performance measures. RESULTS: The visual behavior data showed that drivers had a significantly longer dwell time, a greater number of fixations, and longer maximum fixation duration when driving past an electronic billboard compared to other signs on the same road stretches. No differences were found for the factors day/night, and no effect was found for the driving behavior data. CONCLUSION: Electronic billboards have an effect on gaze behavior by attracting more and longer glances than regular traffic signs. Whether the electronic billboards attract too much attention and constitute a traffic safety hazard cannot be answered conclusively based on the present data.
Address Swedish National Road and Transport Research Institute, Linkoping, Sweden. tania.dukic@vti.se
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ISSN 1538-9588 ISBN Medium (up)
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Notes PMID:23682577 Approved no
Call Number IDA @ john @ Serial 247
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Author Lyytimäki, J.; Rinne, J.
Title Voices for the darkness: online survey on public perceptions on light pollution as an environmental problem Type Journal Article
Year 2013 Publication Journal of Integrative Environmental Sciences Abbreviated Journal Journal of Integrative Environmental Sciences
Volume 10 Issue 2 Pages 127-139
Keywords environmental management; light pollution; public perceptions; survey; public policy
Abstract Light pollution is increasingly affecting ecosystems and human health. We present results from an online survey aimed to chart what aspects of lighting are considered harmful and how light pollution is perceived by the public. We focus on affluent societies by using Finland as an example of a northern industrialised country. The survey generated 2053 responses, particularly from well-educated urban persons living in residential areas and interested in astronomy or environmental issues. The results show that the lighting of residential areas and lighting serving traffic are considered the most common sources of light pollution while commercial lighting is perceived as the most annoying form of light use. Respondents commonly considered light pollution as a disturbance for outdoor recreation and relaxation. The results suggest that the ecological and health effects of light pollution emphasised by the research are poorly known by the people emphasising the aesthetic aspects. The results indicate relatively wide but passive acceptance for policy measures aimed at reducing light pollution.
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ISSN 1943-815X ISBN Medium (up)
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Notes Approved no
Call Number IDA @ john @ Serial 248
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