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Author Kelber, A.
Title Light intensity limits foraging activity in nocturnal and crepuscular bees Type Journal Article
Year 2005 Publication Behavioral Ecology Abbreviated Journal Behavioral Ecology
Volume 17 Issue 1 Pages 63-72
Keywords bees; eyes; foraging; insects; ocelli; sensitivity; visual ecology
Abstract A crepuscular or nocturnal lifestyle has evolved in bees several times independently, probably to explore rewarding pollen sources without competition and to minimize predation and nest parasites. Despite these obvious advantages, only few bee species are nocturnal. Here we show that the sensitivity of the bee apposition eye is a major factor limiting the ability to forage in dim light. We present data on eye size, foraging times, and light levels for Megalopta genalis (Augochlorini, Halictidae) in Panama, and Lasioglossum (Sphecodogastra) sp. (Halictini, Halictidae) in Utah, USA. M. genalis females forage exclusively during twilight, but as a result of dim light levels in the rain forest, they are adapted to extremely low intensities. The likely factor limiting their foraging activity is finding their nest entrance on return from a foraging trip. The lowest light intensity at which they can do this, both in the morning and the evening, is 0.0001 cd m−2. Therefore, they leave the nest at dimmer light levels in the morning than in the evening. Lasioglossum (Sphecodogastra) foraging is limited by light intensity in the evening, but probably by temperature in the morning in the temperate climate of Utah. We propose that the evolution of nocturnality in bees was favored by the large variance in the size of females.
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ISSN 1045-2249 ISBN Medium
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Notes Approved no
Call Number IDA @ john @ Serial 119
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Author Simpson, S.N.; Hanna, B.G.
Title Willingness to pay for a clear night sky: use of the contingent valuation method Type Journal Article
Year 2010 Publication Applied Economics Letters Abbreviated Journal Applied Economics Letters
Volume 17 Issue 11 Pages 1095-1103
Keywords economics; contingent valuation method; light pollution
Abstract This article applies the Contingent Valuation Method (CVM) to the issue of night sky pollution. Light pollution decreases the ability to view a clear, unobstructed night sky. We administered a survey to the students of the Rochester Institute of Technology (RIT) to obtain estimates of Willingness To Pay (WTP) to improve night sky visibility and to prevent deterioration in visibility. This is the first CVM study that attempts to distinguish between these different WTPs. We find that students are willing to pay significantly more for a larger improvement in night sky conditions. We also find significant differences in WTP to improve versus prevent deterioration in night sky conditions.
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ISSN 1350-4851 ISBN Medium
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Notes Approved no
Call Number IDA @ john @ Serial 121
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Author Chen, X.; Nordhaus, W.D.
Title Using luminosity data as a proxy for economic statistics Type Journal Article
Year 2011 Publication Proceedings of the National Academy of Sciences of the United States of America Abbreviated Journal Proc Natl Acad Sci U S A
Volume 108 Issue 21 Pages 8589-8594
Keywords Developing Countries/history/*statistics & numerical data; *Extraterrestrial Environment; History, 20th Century; History, 21st Century; *Light; Methods; *Research Design; Socioeconomic Factors/*history
Abstract A pervasive issue in social and environmental research has been how to improve the quality of socioeconomic data in developing countries. Given the shortcomings of standard sources, the present study examines luminosity (measures of nighttime lights visible from space) as a proxy for standard measures of output (gross domestic product). We compare output and luminosity at the country level and at the 1 degrees latitude x 1 degrees longitude grid-cell level for the period 1992-2008. We find that luminosity has informational value for countries with low-quality statistical systems, particularly for those countries with no recent population or economic censuses.
Address Department of Economics, Yale University, New Haven, CT 06520, USA. xi.chen@yale.edu
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ISSN 0027-8424 ISBN Medium
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Notes PMID:21576474; PMCID:PMC3102367 Approved no
Call Number IDA @ john @ Serial 122
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Author Elvidge, C.D.; Sutton, P.C.; Ghosh, T.; Tuttle, B.T.; Baugh, K.E.; Bhaduri, B.; Bright, E.
Title A global poverty map derived from satellite data Type Journal Article
Year 2009 Publication Computers & Geosciences Abbreviated Journal Computers & Geosciences
Volume 35 Issue 8 Pages 1652-1660
Keywords Poverty; DMSP; Nighttime lights; World development indicators; light pollution
Abstract A global poverty map has been produced at 30 arcsec resolution using a poverty index calculated by dividing population count (LandScan 2004) by the brightness of satellite observed lighting (DMSP nighttime lights). Inputs to the LandScan product include satellite-derived land cover and topography, plus human settlement outlines derived from high-resolution imagery. The poverty estimates have been calibrated using national level poverty data from the World Development Indicators (WDI) 2006 edition. The total estimate of the numbers of individuals living in poverty is 2.2 billion, slightly under the WDI estimate of 2.6 billion. We have demonstrated a new class of poverty map that should improve over time through the inclusion of new reference data for calibration of poverty estimates and as improvements are made in the satellite observation of human activities related to economic activity and technology access.
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ISSN 0098-3004 ISBN Medium
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Notes Approved no
Call Number IDA @ john @ Serial 123
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Author Doll, C.N.H.; Muller, J.-P.; Morley, J.G.
Title Mapping regional economic activity from night-time light satellite imagery Type Journal Article
Year 2006 Publication Ecological Economics Abbreviated Journal Ecological Economics
Volume 57 Issue 1 Pages 75-92
Keywords Night-time light satellite imagery; Economic activity; Geographic information; Mapping; Scale
Abstract The recognition that the elements of the ‘anthropocene’ play a critical role in global change processes means that datasets describing elements of the socio-economic environment are becoming increasingly more desirable. The ability to present these data in a gridded format as opposed to the traditionally reported administrative units is advantageous for incorporation with other environmental datasets. Night-time light remote sensing data has been shown to correlate with national-level figures of Gross Domestic Product (GDP). Night-time radiance data is analysed here along with regional economic productivity data for 11 European Union countries along with the United States at a number of sub-national levels. Night-time light imagery was found to correlate with Gross Regional Product (GRP) across a range of spatial scales. Maps of economic activity at 5 km resolution were produced based on the derived relationships. To produce these maps, certain areas had to be excluded due to their anomalously high levels of economic activity for the amount of total radiance present. These areas were treated separately from other areas in the map. These results provide the first detailed examination of night-time light characteristics with respect to local economic activity and highlight issues, which should be considered when undertaking such analysis.
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ISSN 0921-8009 ISBN Medium
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Notes Approved no
Call Number IDA @ john @ Serial 124
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