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Author Nielsen, E.T.
Title Illumination at twilight Type Journal Article
Year 1963 Publication Okios Abbreviated Journal
Volume 14 Issue (up) 1 Pages 9-21
Keywords Animals; Instrumentation; Methods
Abstract Introduction Poikilotherms with a nocturnal or crepuscular period of activity are usually guided by changes in illumination. The releasing factor may be a certain low level of illumination, or it might be a certain rate of change of intensity or a combination of both. ASCHOFF (1960) has shown that also animals with an internal clock mechanism of activation have to have the “clock” reset by actual changes in illumination. To all students of such animals it is essential to measure light intensity and its changes especially during the twilight period.
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Call Number GFZ @ kyba @ Serial 3196
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Author Stone, J.E.; Phillips, A.J.K.; Ftouni, S.; Magee, M.; Howard, M.; Lockley, S.W.; Sletten, T.L.; Anderson, C.; Rajaratnam, S.M.W.; Postnova, S.
Title Generalizability of A Neural Network Model for Circadian Phase Prediction in Real-World Conditions Type Journal Article
Year 2019 Publication Scientific Reports Abbreviated Journal Sci Rep
Volume 9 Issue (up) 1 Pages 11001
Keywords Human Health; Instrumentation
Abstract A neural network model was previously developed to predict melatonin rhythms accurately from blue light and skin temperature recordings in individuals on a fixed sleep schedule. This study aimed to test the generalizability of the model to other sleep schedules, including rotating shift work. Ambulatory wrist blue light irradiance and skin temperature data were collected in 16 healthy individuals on fixed and habitual sleep schedules, and 28 rotating shift workers. Artificial neural network models were trained to predict the circadian rhythm of (i) salivary melatonin on a fixed sleep schedule; (ii) urinary aMT6s on both fixed and habitual sleep schedules, including shift workers on a diurnal schedule; and (iii) urinary aMT6s in rotating shift workers on a night shift schedule. To determine predicted circadian phase, center of gravity of the fitted bimodal skewed baseline cosine curve was used for melatonin, and acrophase of the cosine curve for aMT6s. On a fixed sleep schedule, the model predicted melatonin phase to within +/- 1 hour in 67% and +/- 1.5 hours in 100% of participants, with mean absolute error of 41 +/- 32 minutes. On diurnal schedules, including shift workers, the model predicted aMT6s acrophase to within +/- 1 hour in 66% and +/- 2 hours in 87% of participants, with mean absolute error of 63 +/- 67 minutes. On night shift schedules, the model predicted aMT6s acrophase to within +/- 1 hour in 42% and +/- 2 hours in 53% of participants, with mean absolute error of 143 +/- 155 minutes. Prediction accuracy was similar when using either 1 (wrist) or 11 skin temperature sensor inputs. These findings demonstrate that the model can predict circadian timing to within +/- 2 hours for the vast majority of individuals on diurnal schedules, using blue light and a single temperature sensor. However, this approach did not generalize to night shift conditions.
Address School of Physics, University of Sydney, Sydney, New South Wales, Australia
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Language English Summary Language Original Title
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ISSN 2045-2322 ISBN Medium
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Notes PMID:31358781; PMCID:PMC6662750 Approved no
Call Number GFZ @ kyba @ Serial 2667
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Author Kocifaj, M.; Bará, S.
Title Night-time monitoring of the aerosol content of the lower atmosphere by differential photometry of the anthropogenic skyglow Type Journal Article
Year 2020 Publication Monthly Notices of the Royal Astronomical Society: Letters Abbreviated Journal
Volume 500 Issue (up) 1 Pages L47-L51
Keywords Skyglow; radiative transfer; scattering; atmospheric effects; instrumentation; photometers; light pollution
Abstract Night-time monitoring of the aerosol content of the lower atmosphere is a challenging task, because appropriate reference natural light sources are lacking. Here, we show that the anthropogenic night-sky brightness due to city lights can be successfully used for estimating the aerosol optical depth of arbitrarily thick atmospheric layers. This method requires measuring the zenith night-sky brightness with two detectors located at the limiting layer altitudes. Combined with an estimate of the overall atmospheric optical depth (available from ground-based measurements or specific satellite products), the ratio of these radiances provides a direct estimate of the differential aerosol optical depth of the air column between these two altitudes. These measurements can be made with single-channel low-cost radiance detectors widely used by the light pollution research community.
Address Faculty of Mathematics, Physics, and Informatics, Comenius University, Mlynská dolina, 842 48 Bratislava, Slovakia ICA, Slovak Academy of Sciences, Dúbravská cesta 9, 845 03 Bratislava, Slovakia; kocifaj ( at ) savba.sk
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Publisher Oxford Academic Place of Publication Editor
Language English Summary Language English Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1745-3925 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 3302
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Author den Outer, P.; Lolkema, D.; Haaima, M.; van der Hoff, R.; Spoelstra, H.; Schmidt, W.
Title Intercomparisons of nine sky brightness detectors Type Journal Article
Year 2011 Publication Sensors (Basel, Switzerland) Abbreviated Journal Sensors (Basel)
Volume 11 Issue (up) 10 Pages 9603-9612
Keywords Calibration; Darkness; *Extraterrestrial Environment; Humans; Light; Luminescent Measurements; Netherlands; *Optical Phenomena; Optics and Photonics/*instrumentation/*methods; Sky Quality Meter; artificial lighting; intercalibration; intercomparison; light pollution; night sky brightness
Abstract Nine Sky Quality Meters (SQMs) have been intercompared during a night time measurement campaign held in the Netherlands in April 2011. Since then the nine SQMs have been distributed across The Netherlands and form the Dutch network for monitoring night sky brightness. The goal of the intercomparison was to infer mutual calibration factors and obtain insight into the variability of the SQMs under different meteorological situations. An ensemble average is built from the individual measurements and used as a reference to infer the mutual calibration factors. Data required additional synchronization prior to the calibration determination, because the effect of moving clouds combined with small misalignments emerges as time jitter in the measurements. Initial scatter of the individual instruments lies between +/-14%. Individual night time sums range from -16% to +20%. Intercalibration reduces this to 0.5%, and -7% to +9%, respectively. During the campaign the smallest luminance measured was 0.657 +/- 0.003 mcd/m(2) on 12 April, and the largest value was 5.94 +/- 0.03 mcd/m(2) on 2 April. During both occurrences interfering circumstances like snow cover or moonlight were absent.
Address National Institute for Public Health and the Environment, A. van Leeuwenhoeklaan 9, 3720 BA Bilthoven, The Netherlands. peter.den.outer@rivm.nl
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Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1424-8220 ISBN Medium
Area Expedition Conference
Notes PMID:22163715; PMCID:PMC3231263 Approved no
Call Number IDA @ john @ Serial 196
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Author Kolláth, Z.; Száz, D.; Kolláth, K.; Tong, K.P.
Title Light Pollution Monitoring and Sky Colours Type Journal Article
Year 2020 Publication Journal of Imaging Abbreviated Journal J. Imaging
Volume 6 Issue (up) 10 Pages 104
Keywords Skyglow; Instrumentation; light pollution; imaging radiometry; colorimetry
Abstract The measurement of night sky quality has become an important task in nature conservation. The primary device used for this task can be a calibrated digital camera. In addition, colour information can be derived from sky photography. In this paper, we provide a test on a concept to gather information about the possible sources of night sky brightness based on digital camera images. This method helps to understand changes in night sky quality due to natural and artificial changes in the environment. We demonstrate that a well-defined colour–colour diagram can differentiate between the different natural and artificial sources of night sky radiance. The colour information can be essential when interpreting long-term evolution of light pollution measurements.
Address Department of Physics, Eötvös Loránd University (ELTE) BDPK, 9700 Szombathely, Hungary; zkollath( at ) gmail.com
Corporate Author Thesis
Publisher MDPI Place of Publication Editor
Language English Summary Language English Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 2313-433X ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 3170
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