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Author Kelber, A.; Balkenius, A.; Warrant, E.J.
Title Scotopic colour vision in nocturnal hawkmoths Type Journal Article
Year 2002 Publication Nature Abbreviated Journal Nature
Volume 419 Issue 6910 Pages (down) 922-925
Keywords Animals; Behavior, Animal; Color; Color Perception/*physiology; Conditioning (Psychology)/physiology; Cues; *Darkness; Discrimination Learning/physiology; Humans; Light; Lighting; Moths/*physiology; Photic Stimulation; Photoreceptor Cells, Invertebrate/physiology; Reward; Sensitivity and Specificity; Ultraviolet Rays
Abstract Humans are colour-blind at night, and it has been assumed that this is true of all animals. But colour vision is as useful for discriminating objects at night as it is during the day. Here we show, through behavioural experiments, that the nocturnal hawkmoth Deilephila elpenor uses colour vision to discriminate coloured stimuli at intensities corresponding to dim starlight (0.0001 cd x m(-2)). It can do this even if the illumination colour changes, thereby showing colour constancy-a property of true colour vision systems. In identical conditions humans are completely colour-blind. Our calculations show that the possession of three photoreceptor classes reduces the absolute sensitivity of the eye, which indicates that colour vision has a high ecological relevance in nocturnal moths. In addition, the photoreceptors of a single ommatidium absorb too few photons for reliable discrimination, indicating that spatial and/or temporal summation must occur for colour vision to be possible. Taken together, our results show that colour vision occurs at nocturnal intensities in a biologically relevant context.
Address Department of Cell and Organism Biology, Vision Group, Lund University, Helgonavagen 3, S-22362 Lund, Sweden. almut.kelber@zool.lu.se
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 0028-0836 ISBN Medium
Area Expedition Conference
Notes PMID:12410310 Approved no
Call Number LoNNe @ kagoburian @ Serial 606
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Author Rea, M. S.; Bierman, A.
Title Spectral considerations for outdoor lighting: Consequences for sky glow Type Journal Article
Year 2014 Publication Lighting Research and Technology Abbreviated Journal Lighting Res. & Tech.
Volume 47 Issue 8 Pages (down) 920-930
Keywords Lighting; skyglow; spectrum; scattering; aerosol; modeling
Abstract It is well known that the magnitude of sky glow on a clear night depends upon the aerosol content in the atmosphere and the spectral power distribution (amount and spectrum). Sources with a greater proportion of short-wavelength radiation produce more backscattered radiation, but as aerosol density increases, the differential effect of spectrum becomes smaller. Sky glow magnitude also depends upon the operating characteristics of the detector and will be greater when the spectrum of the backscattered radiation is tuned to the spectral band-pass characteristics of the detector. The human visual system is most often used to assess sky glow magnitude, but its spectral response is not limited to a single, univariate detector. Rather, the retina is composed of many neural channels, each with its own spectral and absolute sensitivities to optical radiation. Since we can use a different neural channel to see an individual star than we do to gain an overall impression of sky brightness, changes to the spectral power distribution of backscattered radiation differentially, and simultaneously, affect one’s ability to see a single star and to assess sky brightness. A general method for assessing sky glow based upon aerosol content, spectral power distribution and the specific operating characteristics of a detector, human or otherwise, is offered.
Address Lighting Research Center, Rensselaer Polytechnic Institute, Troy, New York, USA
Corporate Author Thesis
Publisher The Society of Light and Lighting Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
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ISSN ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 1065
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Author Rea, M.S.; Bullough, J.D.; Brons, M.S.
Title Spectral considerations for outdoor lighting: Designing for perceived scene brightness Type Journal Article
Year 2014 Publication Lighting Research and Technology Abbreviated Journal Lighting Res. & Tech.
Volume 47 Issue 8 Pages (down) 909-919
Keywords Public Safety; outdoor lighting; photopic; photopic illuminance; human vision; metrics; task lighting; parking lots
Abstract Photopic illuminance is the photometric metric used today for specifying parking lot lighting levels. The photopic luminous efficiency function does not represent the spectral sensitivity of the perceived scene brightness of parking lots. Sources with a greater proportion of short-wavelength radiation will be seen as brighter for the same photopic illuminance. Moreover, the psychological benefit of providing people with a sense of safety and security in a parking lot is better correlated with the perceived brightness of the parking lot than with its photopic illuminance. Because photopic illuminance is not predictive of the psychological benefit expected from the parking lot lighting system, electric energy will be unnecessarily wasted if specifications are based upon this metric. Specifying parking lot lighting with a benefit metric based upon perceived scene brightness could reduce electric power requirements as well as the amount of radiant energy reflecting from the pavement and escaping into the night sky. A method of equating brightness for different spectral power distributions is provided.
Address Lighting Research Center, Rensselaer Polytechnic Institute, Troy, New York, USA
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Notes Approved no
Call Number IDA @ john @ Serial 1074
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Author Valentová, M.; Quicheron, M.; Bertoldi, P.
Title LED Projects and Economic Test Cases in Europe Type Journal Article
Year 2015 Publication International Journal of Green Energy Abbreviated Journal International Journal of Green Energy
Volume 12 Issue 8 Pages (down) 843-851
Keywords Economics; Lighting
Abstract Solid-State Lighting (SSL) is a fast evolving, promising energy-efficient technology, offering a wide range of potential uses. The article presents the status of the existing light emitting diode (LED) pilot actions in Europe, analyzing 106 LED test cases from 17 European countries. Projects from the public and commercial sectors form the focus of this article, with special attention devoted to the economics of LED projects – particularly in terms of energy savings. The results of the test cases demonstrate wide variation. Installations offer energy savings of 59% on average (savings range from 10% to more than 90%). In many applications, LEDs are competitive (with payback time ranging from two to 10 years), yet a large number of projects are still in the trial phase. From the test cases reviewed, the most successful applications are, in terms of savings and economic considerations, replacement of both (1) incandescent light bulbs in traffic light systems, and (2) halogen spotlights in indoor applications. The LED projects bring many co-benefits, including lower maintenance costs, improved lighting characteristics, or improved ambience. Some challenges remain to be addressed, such as to improve the quality characteristics of LEDs and the quality of information and data provided by manufacturers/suppliers, and optimality of LED technology for existing street lighting systems.
Address
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ISSN 1543-5075 ISBN Medium
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Notes Approved no
Call Number LoNNe @ kyba @ Serial 1631
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Author Gago-Calderón, A.; Hermoso-Orzáez, M.; De Andres-Diaz, J.; Redrado-Salvatierra, G.
Title Evaluation of Uniformity and Glare Improvement with Low Energy Efficiency Losses in Street Lighting LED Luminaires Using Laser-Sintered Polyamide-Based Diffuse Covers Type Journal Article
Year 2018 Publication Energies Abbreviated Journal Energies
Volume 11 Issue 4 Pages (down) 816
Keywords Lighting
Abstract Energy saving in street lighting is garnering more interest and has become a priority in municipal management. Therefore, LED luminaires are gradually becoming prevalent in our cities. Beyond their energy/economic saving potential, quality in public lighting installations concerns aspects such as uniformity and glare which must be maintained if not improved in any installation renewal project using this technology. The high light intensity generated in a discrete point in LED packages and its directional nature result in significant deficiencies in these last two parameters. To soften these effects, translucent covers are being used as one of the most common solutions with the drawback of significant light intensity losses. The objective of this paper is to evaluate the behavior of LED luminaire’s polyamide-based optical covers manufactured with a laser-sintered process. These are designed to improve glare and uniformity output, to minimize light output reductions, and to be industrially manufactured with no increment of cost for their lighting equipment compared to conventional transparent polycarbonate solutions. A laboratory and field lighting test study has been applied to different covers with the same LED lamp and luminaire to compare the performance of three different solutions built with different polymeric materials and with different light transmission surface textures. The photometric results have been observed and discussed to demonstrate the ability to significantly improve the lighting performance of LED luminaires—illuminance and uniformity levels and discomfort and disability glare indexes— using an improved optic cover.
Address
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Language Summary Language Original Title
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Series Volume Series Issue Edition
ISSN 1996-1073 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 1844
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