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Author Mortazavi, S.A.R.; Faraz, M.; Laalpour, S.; Kaveh Ahangar, A.; Eslami, J.; Zarei, S.; Mortazavi, G.; Gheisari, F.; Mortazavi, S.M.J.
Title Exposure to Blue Light Emitted from Smartphones in an Environment with Dim Light at Night Alters the Reaction Time of University Students Type Journal Article
Year 2019 Publication Shiraz E-Medical Journal Abbreviated Journal Shiraz E-Med J
Volume Issue Pages e88230
Keywords Human Health; Blue light; smartphone; Reaction Time; shift work
Abstract Background: Substantial evidence now indicates that exposure to visible light at night can be linked to a wide spectrum of disorders ranging from obesity to cancer. More specifically, it has been shown that exposure to short wavelengths in the blue region at night is associated with adverse health effects, such as sleep problems.

Objectives: This study aimed at investigating if exposure to blue light emitted from common smartphones in an environment with dim light at night alters human reaction time.

Methods: Visual reaction time (VRT) of 267 male and female university students were recorded using a simple blind computer-assisted VRT test, respectively. Volunteer university students, who provided their informed consent were randomly divided to two groups of control (N = 126 students) and intervention (N = 141 students). All participants were asked to go to bed at 23:00. Participants in the intervention group were asked to use their smartphones from 23:00 to 24:00 (watching a natural life documentary movie for 60 minutes), while the control group only stayed in bed under low lighting condition, i.e. dim light. Before starting the experiment and after 60 minutes of smartphone use, reaction time was recorded in both groups.

Results: The mean reaction times in the intervention and the control groups before the experiment (23:00) did not show a statistically difference (P = 0.449). The reaction time in the intervention group significantly increased from 412.64 ± 105.60 msec at 23:00 to 441.66 ± 125.78 msec at 24:00 (P = 0.0368) while in the control group, there was no statistically significant difference between the mean reaction times at 23:00 and 24:00.

Conclusions: To the best of the author’s knowledge, this is the first study, which showed that exposure to blue-rich visible light emitted from widely used smartphones increases visual reaction time, which would eventually result in a delay in human responses to different hazards. These findings indicate that people, such as night shift or on call workers, who need to react to stresses rapidly should avoid using their smartphones in a dim light at night.
Address (down) Student Research Committee, School of Medicine, Shiraz University of Medical Sciences, Shiraz, Iran
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1735-1391 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 2534
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Author Falchi, F.; Furgoni, R.; Gallaway, T.A.; Rybnikova, N.A.; Portnov, B.A.; Baugh, K.; Cinzano, P.; Elvidge, C.D.
Title Light pollution in USA and Europe: The good, the bad and the ugly Type Journal Article
Year 2019 Publication Journal of Environmental Management Abbreviated Journal Journal of Environmental Management
Volume 248 Issue Pages 109227
Keywords Remote Sensing; gross domestic product; light pollution; Economics
Abstract Light pollution is a worldwide problem that has a range of adverse effects on human health and natural eco-systems. Using data from the New World Atlas of Artificial Night Sky Brightness, VIIRS-recorded radiance and Gross Domestic Product (GDP) data, we compared light pollution levels, and the light flux to the population size and GDP at the State and County levels in the USA and at Regional (NUTS2) and Province (NUTS3) levels inEurope. We found 6800-fold differences between the most and least polluted regions in Europe, 120-fold differences in their light flux per capita, and 267-fold differences influx per GDP unit. Yet, we found even greater differences between US counties: 200,000-fold differences in sky pollution, 16,000-fold differences in light flux per capita, and 40,000-fold differences in light flux per GDP unit. These findings may inform policy-makers, helping to reduce energy waste and adverse environmental, cultural and health consequences associated with light pollution.
Address (down) STIL – Istituto di Scienza e Tecnologia dell'Inquinamento Luminoso, Light Pollution Science and Technology Institute, Thiene, Italy; Italy. falchi@lightpollution.it(at)istil.it
Corporate Author Thesis
Publisher Elsevier Place of Publication Editor
Language English Summary Language English Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0301-4797 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number IDA @ john @ Serial 2593
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Author Zhang, G.; Li, L.; Jiang, Y.; Shen, X.; Li, D.
Title On-Orbit Relative Radiometric Calibration of the Night-Time Sensor of the LuoJia1-01 Satellite Type Journal Article
Year 2018 Publication Sensors (Basel, Switzerland) Abbreviated Journal Sensors (Basel)
Volume 18 Issue 12 Pages
Keywords Instrumentation; Remote Sensing
Abstract The LuoJia1-01 satellite can acquire high-resolution, high-sensitivity nighttime light data for night remote sensing applications. LuoJia1-01 is equipped with a 4-megapixel CMOS sensor composed of 2048 x 2048 unique detectors that record weak nighttime light on Earth. Owing to minute variations in manufacturing and temporal degradation, each detector's behavior varies when exposed to uniform radiance, resulting in noticeable detector-level errors in the acquired imagery. Radiometric calibration helps to eliminate these detector-level errors. For the nighttime sensor of LuoJia1-01, it is difficult to directly use the nighttime light data to calibrate the detector-level errors, because at night there is no large-area uniform light source. This paper reports an on-orbit radiometric calibration method that uses daytime data to estimate the relative calibration coefficients for each detector in the LuoJia1-01 nighttime sensor, and uses the calibrated data to correct nighttime data. The image sensor has a high dynamic range (HDR) mode, which is optimized for day/night imaging applications. An HDR image can be constructed using low- and high-gain HDR images captured in HDR mode. Hence, a day-to-night radiometric reference transfer model, which uses daytime uniform calibration to calibrate the detector non-uniformity of the nighttime sensor, is herein built for LuoJia1-01. Owing to the lack of calibration equipment on-board LuoJia1-01, the dark current of the nighttime sensor is calibrated by collecting no-light desert images at new moon. The results show that in HDR mode (1) the root mean square of mean for each detector in low-gain (high-gain) images is better than 0.04 (0.07) in digital number (DN) after dark current correction; (2) the DN relationship between low- and high-gain images conforms to the quadratic polynomial mode; (3) streaking metrics are better than 0.2% after relative calibration; and (4) the nighttime sensor has the same relative correction parameters at different exposure times for the same gain parameters.
Address (down) State Key Laboratory of Information Engineering in Surveying, Mapping and Remote Sensing, Wuhan University, Wuhan 430079, China. drli@whu.edu.cn
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 1424-8220 ISBN Medium
Area Expedition Conference
Notes PMID:30513817 Approved no
Call Number GFZ @ kyba @ Serial 2125
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Author Zhen, J.; Pei, T.; Xie, S.
Title Kriging methods with auxiliary nighttime lights data to detect potentially toxic metals concentrations in soil Type Journal Article
Year 2019 Publication The Science of the Total Environment Abbreviated Journal Sci Total Environ
Volume 659 Issue Pages 363-371
Keywords Remote Sensing
Abstract The spatial distribution of potentially toxic metals (PTMs) has been shown to be related to anthropogenic activities. Several auxiliary variables, such as those related to remote sensing data (e.g. digital elevation models, land use, and enhanced vegetation index) and soil properties (e.g. pH, soil type and cation exchange capacity), have been used to predict the spatial distribution of soil PTMs. However, these variables are mostly focused on natural processes or a single aspect of anthropogenic activities and cannot reflect the effects of integrated anthropogenic activities. Nighttime lights (NTL) images, a representative variable of integrated anthropogenic activities, may have the potential to reflect PTMs distribution. To uncover this relationship and determine the effects on evaluation precision, the NTL was employed as an auxiliary variable to map the distribution of PTMs in the United Kingdom. In this study, areas with a digital number (DN)>/=50 and an area>30km(2) were extracted from NTL images to represent regions of high-frequency anthropogenic activities. Subsequently, the distance between the sampling points and the nearest extracted area was calculated. Barium, lead, zinc, copper, and nickel concentrations exhibited the highest correlation with this distance. Their concentrations were mapped using distance as an auxiliary variable through three different kriging methods, i.e., ordinary kriging (OK), cokriging (CK), and regression kriging (RK). The accuracy of the predictions was evaluated using the leave-one-out cross validation method. Regardless of the elements, CK and RK always exhibited lower mean absolute error and root mean square error, in contrast to OK. This indicates that using the NTL as the auxiliary variable indeed enhanced the prediction accuracy for the relevant PTMs. Additionally, RK showed superior results in most cases. Hence, we recommend RK for prediction of PTMs when using the NTL as the auxiliary variable.
Address (down) State Key Laboratory of Geological Processes and Mineral Resources(GPMR), Faculty of Earth Sciences, China University of Geosciences, Wuhan, 430074, China
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 0048-9697 ISBN Medium
Area Expedition Conference
Notes PMID:30599355 Approved no
Call Number GFZ @ kyba @ Serial 2494
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Author Kaplan, K.A.; Mashash, M.; Williams, R.; Batchelder, H.; Starr-Glass, L.; Zeitzer, J.M.
Title Effect of Light Flashes vs Sham Therapy During Sleep With Adjunct Cognitive Behavioral Therapy on Sleep Quality Among Adolescents: A Randomized Clinical Trial Type Journal Article
Year 2019 Publication JAMA Network Open Abbreviated Journal JAMA Netw Open
Volume 2 Issue 9 Pages e1911944
Keywords Human Health
Abstract Importance: Owing to biological, behavioral, and societal factors, sleep duration in teenagers is often severely truncated, leading to pervasive sleep deprivation. Objective: To determine whether a novel intervention, using both light exposure during sleep and cognitive behavioral therapy (CBT), would increase total sleep time in teenagers by enabling them to go to sleep earlier than usual. Design, Setting, and Participants: This double-blind, placebo-controlled, randomized clinical trial, conducted between November 1, 2013, and May 31, 2016, among 102 adolescents enrolled full-time in grades 9 to 12, who expressed difficulty going to bed earlier and waking up early enough, was composed of 2 phases. In phase 1, participants were assigned to receive either 3 weeks of light or sham therapy and were asked to try to go to sleep earlier. In phase 2, participants received 4 brief CBT sessions in addition to a modified light or sham therapy. All analyses were performed on an intent-to-treat basis. Interventions: Light therapy consisted of receiving a 3-millisecond light flash every 20 seconds during the final 3 hours of sleep (phase 1) or final 2 hours of sleep (phase 2). Sham therapy used an identical device, but delivered 1 minute of light pulses (appearing in 20-second intervals, for a total of 3 pulses) per hour during the final 3 hours of sleep (phase 1) or 2 hours of sleep (phase 2). Light therapy occurred every night during the 4-week intervention. Cognitive behavioral therapy consisted of four 50-minute in-person sessions once per week. Main Outcomes and Measures: Primary outcome measures included diary-based sleep times, momentary ratings of evening sleepiness, and subjective measures of sleepiness and sleep quality. Results: Among the 102 participants (54 female [52.9%]; mean [SD] age, 15.6 [1.1] years), 72 were enrolled in phase 1 and 30 were enrolled in phase 2. Mixed-effects models revealed that light therapy alone was inadequate in changing the timing of sleep. However, compared with sham therapy plus CBT alone, light therapy plus CBT significantly moved sleep onset a mean (SD) of 50.1 (27.5) minutes earlier and increased nightly total sleep time by a mean (SD) of 43.3 (35.0) minutes. Light therapy plus CBT also resulted in a 7-fold greater increase in bedtime compliance than that observed among participants receiving sham plus CBT (mean [SD], 2.21 [3.91] vs 0.29 [0.76]), as well as a mean 0.55-point increase in subjective evening sleepiness as compared with a mean 0.48-point decrease in participants receiving sham plus CBT as measured on a 7-point sleepiness scale. Conclusions and Relevance: This study found that light exposure during sleep, in combination with a brief, motivation-focused CBT intervention, was able to consistently move bedtimes earlier and increase total sleep time in teenagers. This type of passive light intervention in teenagers may lead to novel therapeutic applications. Trial Registration: ClinicalTrials.gov identifier: NCT01406691.
Address (down) Stanford Center for Sleep Sciences and Medicine, Department of Psychiatry and Behavioral Sciences, Stanford University, Stanford, California
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 2574-3805 ISBN Medium
Area Expedition Conference
Notes PMID:31553469 Approved no
Call Number GFZ @ kyba @ Serial 2683
Permanent link to this record