Le Tallec, T., Théry, M., & Perret, M. (2016). Melatonin concentrations and timing of seasonal reproduction in male mouse lemurs (Microcebus murinus) exposed to light pollution. J of Mammalogy, 97(3), 753–760.
Abstract: Adverse effects of light at night are associated with human health problems and with changes in seasonal reproduction in several species. Owing to its role in the circadian timing system, melatonin production is suspected to mediate excess nocturnal light. To test this hypothesis, we examined the effect of light pollution on the timing of seasonal reproduction on a strict Malagasy long-day breeder, the nocturnal mouse lemur (Microcebus murinus). We randomly exposed 12 males in wintering sexual rest to moonlight or to a light-mimicking nocturnal streetlight for 5 weeks. We monitored urinary 6-sulfatoxymelatonin concentrations (aMT6s), plasma testosterone concentrations, and testis size, and we recorded daily rhythms of core temperature and locomotor activity. In males exposed to light pollution, we observed a significant decrease in urinary aMT6s concentrations associated with changes in daily rhythm profiles and with activation of reproductive function. These results showed that males entered spontaneous sexual recrudescence leading to a summer acclimatization state, which suggests that light at night disrupts perception of day length cues, leading to an inappropriate photoentrainment of seasonal rhythms.
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Sun, C., & Lian, Z. (2016). Sensitive physiological indicators for human visual comfort evaluation. Lighting Res. & Tech., 48(6), 726–741.
Abstract: Three physiological factors (melatonin levels, tear mucus ferning quality and degree of asthenopia) were examined for their relationship to visual comfort. A lighting environment was created where the illuminance, illuminance uniformity and correlated colour temperature could be adjusted. A three-factor and three-level orthogonal experiment with 24 subjects was designed and carried out. The results indicated that the selected environmental factors had different impacts on the physiological factors. With the illuminance increasing, the melatonin level decreased significantly and the tear mucus ferning quality was improved. However, there is no general influence of illuminance uniformity and correlated colour temperature on the physiological parameters, only differential effects among the three levels were found.
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Mann, M., Melaas, E., & Malik, A. (2016). Using VIIRS Day/Night Band to Measure Electricity Supply Reliability: Preliminary Results from Maharashtra, India. Remote Sensing, 8(9), 711.
Abstract: Unreliable electricity supplies are common in developing countries and impose large socio-economic costs, yet precise information on electricity reliability is typically unavailable. This paper presents preliminary results from a machine-learning approach for using satellite imagery of nighttime lights to develop estimates of electricity reliability for western India at a finer spatial scale. We use data from the Visible Infrared Imaging Radiometer Suite (VIIRS) onboard the Suomi National Polar Partnership (SNPP) satellite together with newly-available data from networked household voltage meters. Our results point to the possibilities of this approach as well as areas for refinement. With currently available training data, we find a limited ability to detect individual outages identified by household-level measurements of electricity voltage. This is likely due to the relatively small number of individual outages observed in our preliminary data. However, we find that the approach can estimate electricity reliability rates for individual locations fairly well, with the predicted versus actual regression yielding an R2 > 0.5. We also find that, despite the after midnight overpass time of the SNPP satellite, the reliability estimates derived are representative of daytime reliability.
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Macgregor, C. J., Evans, D. M., Fox, R., & Pocock, M. J. O. (2016). The dark side of street lighting: impacts on moths and evidence for the disruption of nocturnal pollen transport. Glob Chang Biol, 23(2), 697–707.
Abstract: Among drivers of environmental change, artificial light at night is relatively poorly understood, yet is increasing on a global scale. The community-level effects of existing street lights on moths and their biotic interactions have not previously been studied. Using a combination of sampling methods at matched-pairs of lit and unlit sites, we found significant effects of street lighting: moth abundance at ground level was halved at lit sites, species richness was >25% lower, and flight activity at the level of the light was 70% greater. Furthermore, we found that 23% of moths carried pollen of at least 28 plant species and that there was a consequent overall reduction in pollen transport at lit sites. These findings support the disruptive impact of lights on moth activity, which is one proposed mechanism driving moth declines, and suggest that street lighting potentially impacts upon pollination by nocturnal invertebrates. We highlight the importance of considering both direct and cascading impacts of artificial light.
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Scheffler, T., & Kyba, C. C. M. (2016). Measuring Social Jetlag in Twitter Data. In Proceedings of the Tenth International AAAI Conference on Web and Social Media (ICWSM 2016) (pp. 675–678).
Abstract: Social constraints have replaced the natural cycle of light and darkness as the main determinant of wake-up and activity times for many people. In this paper we show how Twitter activity can be used as a source of large-scale, naturally occurring data for the study of circadian rhythm in humans. Our year-long initial study is based on almost 1.5 million observations by over 200,000 users. The progression of the onset of Twitter activity times on free days in the course of the year is consistent with previous survey-based research on wake
times. We show that the difference in wake-up time (implicating lack of sleep) on weekdays compared to Sundays is between 1 hour and over 2 hours depending on the time of year. The data also supports the assertion that Daylight Saving Time greatly disrupts the easing of social jetlag in the Spring transition.
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