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Author Sutton, P.; Roberts, D.; Elvidge, C.; Baugh, K.
Title Census from Heaven: An estimate of the global human population using night-time satellite imagery Type Journal Article
Year 2001 Publication International Journal of Remote Sensing Abbreviated Journal International Journal of Remote Sensing
Volume 22 Issue 16 Pages 3061-3076
Keywords light at night; DMSP-OLS; remote sensing; satellite
Abstract Night-time satellite imagery provided by the Defense Meteorological Satellite Program's Operational Linescan System (DMSP OLS) is evaluated as a means of estimating the population of all the cities of the world based on their areal extent in the image. A global night-time image product was registered to a dataset of 2000 known city locations with known populations. A relationship between areal extent and city population discovered by Tobler and Nordbeck is identified on a nation by nation basis to estimate the population of the 22 920 urban clusters that exist in the night-time satellite image. The relationship between city population and city areal extent was derived from 1597 city point locations with known population that landed in a 'lit' area of the image. Due to conurbation, these 1597 cities resulted in only 1383 points of analysis for performing regression. When several cities fell into one 'lit' area their populations were summed. The results of this analysis allow for an estimate of the urban population of every nation of the world. By using the known percent of population in urban areas for every nation a total national population was also estimated. The sum of these estimates is a total estimate of the global human population, which in this case was 6.3 billion. This is fairly close to the generally accepted contemporaneous (1997) estimate of the global population which stood at approximately 5.9 billion.
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ISSN 0143-1161 ISBN Medium
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Notes Approved no
Call Number IDA @ john @ Serial 234
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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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Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0960-9822 ISBN Medium
Area Expedition Conference
Notes PMID:24262832 Approved no
Call Number IDA @ john @ Serial 235
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Author Meng, Y.; He, Z.; Yin, J.; Zhang, Y.; Zhang, T.
Title Quantitative calculation of human melatonin suppression induced by inappropriate light at night Type Journal Article
Year 2011 Publication Medical & Biological Engineering & Computing Abbreviated Journal Med Biol Eng Comput
Volume 49 Issue 9 Pages 1083-1088
Keywords Algorithms; Circadian Rhythm/physiology/*radiation effects; Humans; *Lighting; Melatonin/*secretion; *Models, Biological; Retinal Cone Photoreceptor Cells/physiology/radiation effects; Retinal Ganglion Cells/physiology/radiation effects; Retinal Rod Photoreceptor Cells/physiology/radiation effects
Abstract Melatonin (C(1)(3)H(1)(6)N(2)O(2)) has a wide range of functions in the body. When is inappropriately exposed to light at night, human circadian rhythm will be interfered and then melatonin secretion will become abnormal. For nearly three decades great progresses have been achieved in analytic action spectra and melatonin suppression by various light conditions. However, so far few articles focused on the quantitative calculation of melatonin suppression induced by light. In this article, an algorithm is established, in which all the contributions of rods, cones, and intrinsically photosensitive retinal ganglion cells are considered. Calculation results accords with the experimental data in references very well, which indicate the validity of this algorithm. This algorithm can also interpret the rule of melatonin suppression varying with light correlated color temperature very well.
Address Photonics Research Center, School of Physics, Nankai University, Tianjin 300071, China
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Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0140-0118 ISBN Medium
Area Expedition Conference
Notes PMID:21717231 Approved no
Call Number IDA @ john @ Serial 236
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Author Inger, R.; Bennie, J.; Davies, T.W.; Gaston, K.J.
Title Potential biological and ecological effects of flickering artificial light Type Journal Article
Year 2014 Publication PloS one Abbreviated Journal PLoS One
Volume 9 Issue 5 Pages e98631
Keywords flickering; artificial light; biology
Abstract Organisms have evolved under stable natural lighting regimes, employing cues from these to govern key ecological processes. However, the extent and density of artificial lighting within the environment has increased recently, causing widespread alteration of these regimes. Indeed, night-time electric lighting is known significantly to disrupt phenology, behaviour, and reproductive success, and thence community composition and ecosystem functioning. Until now, most attention has focussed on effects of the occurrence, timing, and spectral composition of artificial lighting. Little considered is that many types of lamp do not produce a constant stream of light but a series of pulses. This flickering light has been shown to have detrimental effects in humans and other species. Whether a species is likely to be affected will largely be determined by its visual temporal resolution, measured as the critical fusion frequency. That is the frequency at which a series of light pulses are perceived as a constant stream. Here we use the largest collation to date of critical fusion frequencies, across a broad range of taxa, to demonstrate that a significant proportion of species can detect such flicker in widely used lamps. Flickering artificial light thus has marked potential to produce ecological effects that have not previously been considered.
Address Environment and Sustainability Institute, University of Exeter, Penryn, Cornwall, United Kingdom
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ISSN 1932-6203 ISBN Medium
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Notes PMID:24874801; PMCID:PMC4038456 Approved no
Call Number IDA @ john @ Serial 237
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Author LeGates, T.A.; Altimus, C.M.; Wang, H.; Lee, H.-K.; Yang, S.; Zhao, H.; Kirkwood, A.; Weber, E.T.; Hattar, S.
Title Aberrant light directly impairs mood and learning through melanopsin-expressing neurons Type Journal Article
Year 2012 Publication Nature Abbreviated Journal Nature
Volume 491 Issue 7425 Pages 594-598
Keywords Affect/drug effects/physiology/*radiation effects; Animals; Antidepressive Agents/pharmacology; Body Temperature Regulation/physiology/radiation effects; Circadian Rhythm/physiology; Cognition/drug effects/physiology/radiation effects; Corticosterone/metabolism; Depression/etiology/physiopathology; Desipramine/pharmacology; Fluoxetine/pharmacology; Learning/drug effects/physiology/*radiation effects; *Light; Long-Term Potentiation/drug effects; Male; Memory/physiology/radiation effects; Mice; Photoperiod; Retinal Ganglion Cells/drug effects/*metabolism/*radiation effects; *Rod Opsins/analysis; Sleep/physiology; Wakefulness/physiology
Abstract The daily solar cycle allows organisms to synchronize their circadian rhythms and sleep-wake cycles to the correct temporal niche. Changes in day-length, shift-work, and transmeridian travel lead to mood alterations and cognitive function deficits. Sleep deprivation and circadian disruption underlie mood and cognitive disorders associated with irregular light schedules. Whether irregular light schedules directly affect mood and cognitive functions in the context of normal sleep and circadian rhythms remains unclear. Here we show, using an aberrant light cycle that neither changes the amount and architecture of sleep nor causes changes in the circadian timing system, that light directly regulates mood-related behaviours and cognitive functions in mice. Animals exposed to the aberrant light cycle maintain daily corticosterone rhythms, but the overall levels of corticosterone are increased. Despite normal circadian and sleep structures, these animals show increased depression-like behaviours and impaired hippocampal long-term potentiation and learning. Administration of the antidepressant drugs fluoxetine or desipramine restores learning in mice exposed to the aberrant light cycle, suggesting that the mood deficit precedes the learning impairments. To determine the retinal circuits underlying this impairment of mood and learning, we examined the behavioural consequences of this light cycle in animals that lack intrinsically photosensitive retinal ganglion cells. In these animals, the aberrant light cycle does not impair mood and learning, despite the presence of the conventional retinal ganglion cells and the ability of these animals to detect light for image formation. These findings demonstrate the ability of light to influence cognitive and mood functions directly through intrinsically photosensitive retinal ganglion cells.
Address Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218, USA
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Series Volume Series Issue Edition
ISSN 0028-0836 ISBN Medium
Area Expedition Conference
Notes PMID:23151476; PMCID:PMC3549331 Approved no
Call Number IDA @ john @ Serial 238
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