Touitou, Y., Reinberg, A., & Touitou, D. (2017). Association between light at night, melatonin secretion, sleep deprivation, and the internal clock: Health impacts and mechanisms of circadian disruption. Life Sci, 173, 94–106.
Abstract: Exposure to Artificial Light At Night (ALAN) results in a disruption of the circadian system, which is deleterious to health. In industrialized countries, 75% of the total workforce is estimated to have been involved in shift work and night work. Epidemiologic studies, mainly of nurses, have revealed an association between sustained night work and a 50-100% higher incidence of breast cancer. The potential and multifactorial mechanisms of the effects include the suppression of melatonin secretion by ALAN, sleep deprivation, and circadian disruption. Shift and/or night work generally decreases the time spent sleeping, and it disrupts the circadian time structure. In the long run, this desynchronization is detrimental to health, as underscored by a large number of epidemiological studies that have uncovered elevated rates of several diseases, including cancer, diabetes, cardiovascular risks, obesity, mood disorders and age-related macular degeneration. It amounts to a public health issue in the light of the very substantial number of individuals involved. The IARC has classified shift work in group 2A of “probable carcinogens to humans” since “they involve a circadian disorganization”. Countermeasures to the effects of ALAN, such as melatonin, bright light, or psychotropic drugs, have been proposed as a means to combat circadian clock disruption and improve adaptation to shift and night work. We review the evidence for the ALAN impacts on health. Furthermore, we highlight the importance of an in-depth mechanistic understanding to combat the detrimental properties of exposure to ALAN and develop strategies of prevention.
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Heo, J. - Y., Kim, K., Fava, M., Mischoulon, D., Papakostas, G. I., Kim, M. - J., et al. (2017). Effects of smartphone use with and without blue light at night in healthy adults: A randomized, double-blind, cross-over, placebo-controlled comparison. J Psychiatr Res, 87, 61–70.
Abstract: Smartphones deliver light to users through Light Emitting Diode (LED) displays. Blue light is the most potent wavelength for sleep and mood. This study investigated the immediate effects of smartphone blue light LED on humans at night. We investigated changes in serum melatonin levels, cortisol levels, body temperature, and psychiatric measures with a randomized, double-blind, cross-over, placebo-controlled design of two 3-day admissions. Each subject played smartphone games with either conventional LED or suppressed blue light from 7:30 to 10:00PM (150 min). Then, they were readmitted and conducted the same procedure with the other type of smartphone. Serum melatonin levels were measured in 60-min intervals before, during and after use of the smartphones. Serum cortisol levels and body temperature were monitored every 120 min. The Profile of Mood States (POMS), Epworth Sleepiness Scale (ESS), Fatigue Severity Scale (FSS), and auditory and visual Continuous Performance Tests (CPTs) were administered. Among the 22 participants who were each admitted twice, use of blue light smartphones was associated with significantly decreased sleepiness (Cohen's d = 0.49, Z = 43.50, p = 0.04) and confusion-bewilderment (Cohen's d = 0.53, Z = 39.00, p = 0.02), and increased commission error (Cohen's d = -0.59, t = -2.64, p = 0.02). Also, users of blue light smartphones experienced a longer time to reach dim light melatonin onset 50% (2.94 vs. 2.70 h) and had increases in body temperature, serum melatonin levels, and cortisol levels, although these changes were not statistically significant. Use of blue light LED smartphones at night may negatively influence sleep and commission errors, while it may not be enough to lead to significant changes in serum melatonin and cortisol levels.
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Warrant, E. (2016). Superior vision in nocturnal insects inspires new night vision technologies. SPIE Newsroom.
Abstract: Algorithms that dramatically improve the quality of video sequences captured in very dim light have been developed on the basis of the neural mechanisms in nocturnal insects with excellent visual capabilities.
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Challéat, S., & Lapostolle, D. (2014). Concilier éclairage urbain et environnement nocturne : Les enjeux d’une controverse sociotechnique. Nat. Sci. Soc., 22(4), 317–328.
Abstract: La question de l’éclairage urbain nocturne est posée publiquement de manière de plus en plus significative, d’abord aux États-Unis puis en Europe. Cantonnée à l’origine au domaine de l’astronomie, cette question pose problème dans différents secteurs : l’environnement, la santé, l’urbanisme, mais aussi et surtout l’énergie... En croisant une approche sociologique avec une approche géographique, les auteurs font le récit d’une controverse environnementale aboutissant, en France, à l’inscription de la notion de pollution lumineuse dans la loi Grenelle et questionnent sa dimension spatiale. Ils montrent les différentes logiques et interprétations, à l’œuvre autour de la distinction entre « pollution » et « nuisance » lumineuses, qui traversent les scènes de négociation sur les processus de normalisation et la mobilisation d’outils de zonage.
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Delhey, K., & Peters, A. (2016). Implications for conservation of anthropogenic impacts on visual communication and camouflage. Conserv Biol, 31(1), 30–39.
Abstract: Anthropogenic environmental impacts can disrupt the sensory environment of animals and affect important processes from mate choice to predator avoidance. Currently these effects are best understood for auditory and chemo-sensory modalities and recent reviews highlight their importance for conservation. Here we summarise how anthropogenic changes to the visual environment (ambient light, transmission, backgrounds) affect visual communication and camouflage, and highlight implications for conservation. These implications are particularly evident for disrupted camouflage due to its tight links with survival while the conservation importance of impaired visual communication is less well-documented. Such effects can be potentially severe when they affect critical processes such as pollination or species recognition. However, when impaired mate choice does not lead to hybridization, the conservation consequences are less clear. We suggest that the demographic effects of human impacts on visual communication and camouflage will be particularly strong when: (a) human-induced modifications to the visual environment are evolutionary novel, that is, very different from natural variation, (b) affected species and populations have low levels of intraspecific (genotypic and phenotypic) variation and low levels of behavioural, sensory or physiological plasticity and (c) the processes affected are directly related to survival (camouflage), species recognition, or number of offspring produced, rather than offspring quality or attractiveness. The evidence summarized here suggests that anthropogenic effects on the visual environment might be of similar conservation concerns as those on other sensory modalities. This article is protected by copyright. All rights reserved.
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