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Semeniuk, K. (Ed.). (2014). Gazing Up: An Exploration of Municipal Night Lighting Practices Amongst Six Canadian Municipalities. Master's thesis, University of Guelph, Guelph, Ontario.
Abstract: Light pollution is broadly defined as the unnecessary illumination of the nocturnal environment. Light pollution is a pervasive phenomena shown to have harmful consequences for both the biotic and abiotic components of an ecosystem. While some municipalities have begun to address the environmental and economic costs of light pollution, most have not. The goal of this study was to investigate current municipal night lighting practices for six selected Canadian municipalities with the aim of determining their policies and practices for night lighting. Semi-structured interviews with key informants were conducted and analyzed using a mixed methods approach that included a thorough literature review. The results indicate that rising energy costs, aging infrastructure and the lighting industry are driving the majority of changes taking place in adapting municipalities while most municipalities remain content with status quo. The research conducted led to guideline improvements for municipal night lighting in todayâs municipalities.
Bedrosian, T. A. (Ed.). (2013). Circadian Disruption by Light at Night: Implications for Mood. Ph.D. thesis, , .
Abstract: Life on Earth has adapted to a consistent 24-h solar cycle. Circadian rhythms in physiology and behavior remain synchronized to the environment using light as the most potent entraining cue. During the past century, however, the widespread adoption of electric light has led to `round-the-clockâ societies. Instead of aligning with the environment, individuals follow artificial and often erratic light cycles created by social and work schedules. In particular, exposure to artificial light at night (LAN), termed âlight pollutionâ, has become pervasive over the past 100 years. Virtually every individual living in the U.S. and Europe experiences this aberrant light exposure, and moreover about 20% of the population performs shift work. LAN may disrupt physiological timekeeping, leading to dysregulation of internal processes and misalignment between behavior and the environment. Recent evidence suggests that individuals exposed to excessive LAN, such as night shift workers, have increased risk for depressive disorders, but the biological mechanism remains unspecified. In mammals, intrinsically photosensitive retinal ganglion cells (ipRGCs) project light information to (1) the suprachiasmatic nucleus (SCN) in the hypothalamus, regulating circadian rhythms, and (2) to limbic regions, putatively regulating mood. Thus, LAN has the potential to affect both circadian timekeeping and mood. In this dissertation, I present evidence from rodent studies supporting the novel hypothesis that night-time exposure to light disrupts circadian organization and contributes to depressed mood. First, I consider the physiological and behavioral consequences associated with unnatural exposure to LAN. The effects of LAN on circadian output are considered in terms of locomotor activity, the diurnal cortisol rhythm, and diurnal clock protein expression in the brain in Chapter 2. The influence of LAN on behavior and brain plasticity is discussed, with particular focus on depressive-like behavior (Chapter 3) and effects of SSRI treatment (Chapter 4). Effects of LAN on structural plasticity and gene expression in the brain are described, with emphasis on potential correlates of the depressive-like behavior observed under LAN in Chapter 5. Given the prevalence of LAN exposure and its importance, strategies for reversing the effects are offered. Specifically, eliminating LAN quickly reverses behavioral and physiological effects of exposure as described in Chapter 5. In Chapter 6 I report that administration of a pharmacological cytokine inhibitor prevents depressive-like behaviors in LAN, implicating brain inflammation in the behavioral effect. Finally, I demonstrate in Chapter 7 that exposure to red wavelength LAN reduces the effects on brain and behavior, suggesting that LAN acts through specific retinal pathways involving melanopsin. Taken together, these studies demonstrate the consequences of LAN, but also outline potential avenues for prevention or intervention.
Fuller, G. (Ed.). (2013). The Night Shift: Lighting and Nocturnal Strepsirrhine Care in Zoos. Ph.D. thesis, , .
Abstract: Over billions of years of evolution, light from the sun, moon, and stars has provided
organisms with reliable information about the passage of time. Photic cues entrain
the circadian system, allowing animals to perform behaviors critical for survival and
reproduction at optimal times. Modern artificial lighting has drastically altered
environmental light cues. Evidence is accumulating that exposure to light at night
(particularly blue wavelengths) from computer screens, urban light pollution, or as
an occupational hazard of night-shift work has major implications for human health.
Nocturnal animals are the shift workers of zoos; they are generally housed on
reversed light cycles so that daytime visitors can observe their active behaviors. As a
result, they are exposed to artificial light throughout their subjective night. The goal
of this investigation was to examine critically the care of nocturnal strepsirrhine
primates in North American zoos, focusing on lorises (Loris and Nycticebus spp.) and pottos (Perodicticus potto). The general hypothesis was that exhibit lighting design affects activity patterns and circadian physiology in nocturnal strepsirrhines. The
first specific aim was to assess the status of these populations. A multi-institutional husbandry survey revealed little consensus among zoos in lighting design, with both red and blue light commonly used for nocturnal illumination. A review of medical records also revealed high rates of neonate mortality. The second aim was to
develop methods for measuring the effects of exhibit lighting on behavior and
health. The use of actigraphy for automated activity monitoring was explored.
Methods were also developed for measuring salivary melatonin and cortisol as
indicators of circadian disruption. Finally, a multi-institutional study was conducted
comparing behavioral and endocrine responses to red and blue dark phase lighting.
These results showed greater activity levels in strepsirrhines housed under red light than blue. Salivary melatonin concentrations in pottos suggested that blue light
suppressed nocturnal melatonin production at higher intensities, but evidence for
circadian disruption was equivocal. These results add to the growing body of
evidence on the detrimental effects of blue light at night and are a step towards
empirical recommendations for nocturnal lighting design in zoos.
Luo, W. (Ed.). (2014). Outdoor lighting – Mesopic photometry, adaptation conditions and user preferences in pedestrian way lighting. Ph.D. thesis, , .
Abstract: The starting point of this work is to review the current recommendations and criteria of road and pedestrian way lighting. At present, the emphasis of traffic safety, the increasing energy costs, and improvements in mesopic photometry have led to new discussions about the accuracy of the recommendations for road lighting. Sufficient road lighting is generally based on the lighting requirements given in different lighting classes.
For road lighting, the value of 2 cd/m2 is recommended as the minimum average road surface luminance for the highest lighting class in the CIE and CEN publications. The basis of the average road surface luminance for the lower lighting classes is unknown and lacks experimental works. Moreover, the experimental set-ups of the studies conducted in the 1930s and 1950s do not meet the conditions of motor traffic lighting nowadays. They also have deficiencies in the number and age distributions of the subjects. The values of the average horizontal illuminances of the pedestrian way lighting recommendations are based on studies conducted in the 1970s and 1980s. However, no information exists on how the recommended illuminance values are derived for the different lighting classes.
The current recommendations for outdoor lighting are based on photopic photometry, this is daylight visibility conditions. In outdoor lighting, the luminances are in the mesopic range. The CIE recommended system for mesopic photometry should be used in providing recommendations and criteria for both road and pedestrian way lighting. Before implementing mesopic photometry, the adaptation luminance of the road users should be known. This study examined the adaptation conditions of pedestrians based on eye-tracking measurements. A case study in a pedestrian way was conducted in Chongqing of China. The study is related to the currently ongoing task of the CIE JCT-1 Implementation of CIE 191 System for Mesopic Photometry in Outdoor Lighting, which is to investigate adaptation and viewing conditions and define visual adaptation fields in outdoor lighting. The case study consisted of eye-tracking measurements and subjective evaluations of the lighting conditions.
It was found that the eye-fixation areas and locations were around a central area of the road surface in the horizontal level but spread over a wider area in the vertical level. The subjective importance of facial recognition depends on the specific visual tasks at different light levels in a pedestrian way. The results also suggest that further studies using an eye-tracking system could combine eye-fixation data with pupil size and luminance data. This would help in further analysis of visual adaptation fields of the road users.
Provencio, I., Rodriguez, I. R., Jiang, G., Hayes, W. P., Moreira, E. F., & Rollag, M. D. (2000). A Novel Human Opsin in the Inner Retina.20(2), 600–605.
Abstract: Here we report the identification of a novel human opsin, melanopsin, that is expressed in cells of the mammalian inner retina. The human melanopsin gene consists of 10 exons and is mapped to chromosome 10q22. This chromosomal localization and gene structure differs significantly from that of other human opsins that typically have four to seven exons. A survey of 26 anatomical sites indicates that, in humans, melanopsin is expressed only in the eye. In situ hybridization histochemistry shows that melanopsin expression is restricted to cells within the ganglion and amacrine cell layers of the primate and murine retinas. Notably, expression is not observed in retinal photoreceptor cells, the opsin-containing cells of the outer retina that initiate vision. The unique inner retinal localization of melanopsin suggests that it is not involved in image formation but rather may mediate nonvisual photoreceptive tasks, such as the regulation of circadian rhythms and the acute suppression of pineal melatonin. The anatomical distribution of melanopsin-positive retinal cells is similar to the pattern of cells known to project from the retina to the suprachiasmatic nuclei of the hypothalamus, a primary circadian pacemaker.