Artificial light at night affects sleep behaviour differently in two closely related songbird species.

Science.gov (United States)

Sun, Jiachen; Raap, Thomas; Pinxten, Rianne; Eens, Marcel

2017-12-01

Artificial light at night (ALAN) or light pollution is an increasing and worldwide problem. There is growing concern that because of the disruption of natural light cycles, ALAN may pose serious risks for wildlife. While ALAN has been shown to affect many aspects of animal behaviour and physiology, few studies have experimentally studied whether individuals of different species in the wild respond differently to ALAN. Here, we investigated the effect of ALAN on sleep behaviour in two closely related songbird species inhabiting the same study area and roosting/breeding in similar nest boxes. We experimentally exposed free-living great tits (Parus major) and blue tits (Cyanistes caeruleus) to artificial light inside their nest boxes and observed changes in their sleep behaviour compared to the previous night when the nest boxes were dark. In line with previous studies, sleep behaviour of both species did not differ under dark conditions. ALAN disrupted sleep in both great and blue tits. However, compared to blue tits, great tits showed more pronounced effects and more aspects of sleep were affected. Light exposed great tits entered the nest boxes and fell asleep later, woke up and exited the nest boxes earlier, and the total sleep amount and sleep percentage were reduced. By contrast, these changes in sleep behaviour were not found in light exposed blue tits. Our field experiment, using exactly the same light manipulation in both species, provides direct evidence that two closely related species respond differently to ALAN, while their sleep behaviour under dark conditions was similar. Our research suggests that findings for one species cannot necessarily be generalised to other species, even closely-related species. Furthermore, species-specific effects could have implications for community dynamics. Copyright © 2017 Elsevier Ltd. All rights reserved.

Dose-dependent responses of avian daily rhythms to artificial light at night

NARCIS (Netherlands)

Jong, de M.; Jeninga, L.; Ouyang, J.Q.; Oers, van K.; Spoelstra, K.; Visser, M.E.

2016-01-01

Recent studies have shown that animals are affected by night-time light exposure. Light is a continuous variable, but our knowledge on how individuals react to different light intensities during the night is limited. We therefore determined the relationship between night light intensity and the

Do wild great tits avoid exposure to light at night?

NARCIS (Netherlands)

De Jong, M.; Ouyang, Jenny; van Grunsven, Roy H. A.; Visser, M.E.; Spoelstra, K.

2016-01-01

Studies of wild populations have provided important insights into the effects of artificial light at night on organisms, populations and ecosystems. However, in most studies the exact amount of light at night individuals are exposed to remains unknown. Individuals can potentially control their

Artificial light pollution increases nocturnal vigilance in peahens.

Science.gov (United States)

Yorzinski, Jessica L; Chisholm, Sarah; Byerley, Sydney D; Coy, Jeanee R; Aziz, Aisyah; Wolf, Jamie A; Gnerlich, Amanda C

2015-01-01

Artificial light pollution is drastically changing the sensory environments of animals. Even though many animals are now living in these changed environments, the effect light pollution has on animal behavior is poorly understood. We investigated the effect of light pollution on nocturnal vigilance in peahens (Pavo cristatus). Captive peahens were exposed to either artificial lighting or natural lighting at night. We employed a novel method to record their vigilance behavior by attaching accelerometers to their heads and continuously monitoring their large head movements. We found that light pollution significantly increases nocturnal vigilance in peahens. Furthermore, the birds faced a trade-off between vigilance and sleep at night: peahens that were more vigilant spent less time sleeping. Given the choice, peahens preferred to roost away from high levels of artificial lighting but showed no preference for roosting without artificial lighting or with low levels of artificial lighting. Our study demonstrates that light pollution can have a substantial impact on animal behavior that can potentially result in fitness consequences.

Do wild great tits avoid exposure to light at night?

NARCIS (Netherlands)

Jong, De Maaike; Ouyang, Jenny Q.; Grunsven, van Roy H.A.; Visser, Marcel E.; Spoelstra, Kamiel

2016-01-01

Studies of wild populations have provided important insights into the effects of artificial light at night on organisms, populations and ecosystems. However, in most studies the exact amount of light at night individuals are exposed to remains unknown. Individuals can potentially control their

Artificial night lighting rather than traffic noise affects the daily timing of dawn and dusk singing in common European songbirds

NARCIS (Netherlands)

Da Silva, Arnaud; Samplonius, Jelmer Menno; Schlicht, Emmi; Valcu, Mihai; Kempenaers, Bart

2014-01-01

It is well established that artificial night lighting can influence animal orientation, but there is less information about its effects on other behaviors. Previous work suggested that light pollution can affect both seasonal and daily patterns of behavior. The aim of our study was to investigate

Barriers and benefits: implications of artificial night-lighting for the distribution of common bats in Britain and Ireland

Science.gov (United States)

Mathews, Fiona; Roche, Niamh; Aughney, Tina; Jones, Nicholas; Day, Julie; Baker, James; Langton, Steve

2015-01-01

Artificial lighting is a particular problem for animals active at night. Approximately 69% of mammal species are nocturnal, and one-third of these are bats. Due to their extensive movements—both on a nightly basis to exploit ephemeral food supplies, and during migration between roosts—bats have an unusually high probability of encountering artificial light in the landscape. This paper reviews the impacts of lighting on bats and their prey, exploring the direct and indirect consequences of lighting intensity and spectral composition. In addition, new data from large-scale surveys involving more than 265 000 bat calls at more than 600 locations in two countries are presented, showing that prevalent street-lighting types are not generally linked with increased activity of common and widespread bat species. Such bats, which are important to ecosystem function, are generally considered ‘light-attracted’ and likely to benefit from the insect congregations that form at lights. Leisler's bat (Nyctalus leisleri) may be an exception, being more frequent in lit than dark transects. For common pipistrelle bats (Pipistrellus pipistrellus), lighting is negatively associated with their distribution on a landscape scale, but there may be local increases in habitats with good tree cover. Research is now needed on the impacts of sky glow and glare for bat navigation, and to explore the implications of lighting for habitat matrix permeability. PMID:25780236

Penguin colony attendance under artificial lights for ecotourism.

Science.gov (United States)

Rodríguez, Airam; Holmberg, Ross; Dann, Peter; Chiaradia, André

2018-03-30

Wildlife watching is an emerging ecotourism activity around the world. In Australia and New Zealand, night viewing of little penguins attracts hundreds of thousands of visitors per year. As penguins start coming ashore after sunset, artificial lighting is essential to allow visitors to view them in the dark. This alteration of the nightscape warrants investigation for any potential effects of artificial lighting on penguin behavior. We experimentally tested how penguins respond to different light wavelengths (colors) and intensities to examine effects on the colony attendance behavior at two sites on Phillip Island, Australia. At one site, nocturnal artificial illumination has been used for penguin viewing for decades, whereas at the other site, the only light is from the natural night sky. Light intensity did not affect colony attendance behaviors of penguins at the artificially lit site, probably due to penguin habituation to lights. At the not previously lit site, penguins preferred lit paths over dark paths to reach their nests. Thus, artificial light might enhance penguin vision at night and consequently it might reduce predation risk and energetic costs of locomotion through obstacle and path detection. Although penguins are faithful to their path, they can be drawn to artificial lights at small spatial scale, so light pollution could attract penguins to undesirable lit areas. When artificial lighting is required, we recommend keeping lighting as dim and time-restricted as possible to mitigate any negative effects on the behavior of penguins and their natural habitat. © 2018 Wiley Periodicals, Inc.

Artificial light pollution increases nocturnal vigilance in peahens

Directory of Open Access Journals (Sweden)

Jessica L. Yorzinski

2015-08-01

Full Text Available Artificial light pollution is drastically changing the sensory environments of animals. Even though many animals are now living in these changed environments, the effect light pollution has on animal behavior is poorly understood. We investigated the effect of light pollution on nocturnal vigilance in peahens (Pavo cristatus. Captive peahens were exposed to either artificial lighting or natural lighting at night. We employed a novel method to record their vigilance behavior by attaching accelerometers to their heads and continuously monitoring their large head movements. We found that light pollution significantly increases nocturnal vigilance in peahens. Furthermore, the birds faced a trade-off between vigilance and sleep at night: peahens that were more vigilant spent less time sleeping. Given the choice, peahens preferred to roost away from high levels of artificial lighting but showed no preference for roosting without artificial lighting or with low levels of artificial lighting. Our study demonstrates that light pollution can have a substantial impact on animal behavior that can potentially result in fitness consequences.

Migratory bats respond to artificial green light with positive phototaxis.

Directory of Open Access Journals (Sweden)

Christian C Voigt

Full Text Available Artificial light at night is spreading worldwide at unprecedented rates, exposing strictly nocturnal animals such as bats to a novel anthropogenic stressor. Previous studies about the effect of artificial light on bats focused almost exclusively on non-migratory species, yet migratory animals such as birds are known to be largely affected by light pollution. Thus, we conducted a field experiment to evaluate if bat migration is affected by artificial light at night. In late summer, we presented artificial green light of 520 nm wavelength to bats that were migrating south along the shoreline of the Baltic Sea. Using a light on-off treatment, we observed that the activity of Pipistrellus nathusii and P. pygmaeus, the two most abundant migratory species at our site, increased by more than 50% in the light-on compared to the light-off treatment. We observed an increased number of feeding buzzes during the light-on compared to the light-off treatment for P. nathusii. However, feeding activity was low in general and did not increase disproportionately during the light-on treatment in relation to the overall echolocation call activity of bats. Further, P. nathusii were attracted towards the green light at a distance of about 23 m, which is way beyond the echolocation detection range for insects of Nathusius' bats. We therefore infer that migratory bats were not attracted to artificial green light because of high insect densities, but instead by positive phototaxis. We conclude that artificial light at night may potentially impact bat migration in a yet unrecognized way.

Reducing the ecological consequences of night-time light pollution: options and developments.

Science.gov (United States)

Gaston, Kevin J; Davies, Thomas W; Bennie, Jonathan; Hopkins, John

2012-12-01

1. Much concern has been expressed about the ecological consequences of night-time light pollution. This concern is most often focused on the encroachment of artificial light into previously unlit areas of the night-time environment, but changes in the spectral composition, duration and spatial pattern of light are also recognized as having ecological effects.2. Here, we examine the potential consequences for organisms of five management options to reduce night-time light pollution. These are to (i) prevent areas from being artificially lit; (ii) limit the duration of lighting; (iii) reduce the 'trespass' of lighting into areas that are not intended to be lit (including the night sky); (iv) change the intensity of lighting; and (v) change the spectral composition of lighting.3. Maintaining and increasing natural unlit areas is likely to be the most effective option for reducing the ecological effects of lighting. However, this will often conflict with other social and economic objectives. Decreasing the duration of lighting will reduce energy costs and carbon emissions, but is unlikely to alleviate many impacts on nocturnal and crepuscular animals, as peak times of demand for lighting frequently coincide with those in the activities of these species. Reducing the trespass of lighting will maintain heterogeneity even in otherwise well-lit areas, providing dark refuges that mobile animals can exploit. Decreasing the intensity of lighting will reduce energy consumption and limit both skyglow and the area impacted by high-intensity direct light. Shifts towards 'whiter' light are likely to increase the potential range of environmental impacts as light is emitted across a broader range of wavelengths.4.Synthesis and applications. The artificial lightscape will change considerably over coming decades with the drive for more cost-effective low-carbon street lighting solutions and growth in the artificially lit area. Developing lighting strategies that minimize adverse

Effects of day-time exposure to different light intensities on light-induced melatonin suppression at night.

Science.gov (United States)

Kozaki, Tomoaki; Kubokawa, Ayaka; Taketomi, Ryunosuke; Hatae, Keisuke

2015-07-04

Bright nocturnal light has been known to suppress melatonin secretion. However, bright light exposure during the day-time might reduce light-induced melatonin suppression (LIMS) at night. The effective proportion of day-time light to night-time light is unclear; however, only a few studies on accurately controlling both day- and night-time conditions have been conducted. This study aims to evaluate the effect of different day-time light intensities on LIMS. Twelve male subjects between the ages of 19 and 23 years (mean ± S.D., 20.8 ± 1.1) gave informed consent to participate in this study. They were exposed to various light conditions (day-time light conditions). They were then exposed to bright light (300 lx) again between 01:00 and 02:30 (night-time light exposure). They provided saliva samples before (00:55) and after night-time light exposure (02:30). A one-tailed paired t test yielded significant decrements of melatonin concentration after night-time light exposure under day-time dim, 100- and 300-lx light conditions. No significant differences exist in melatonin concentration between pre- and post-night-time light exposure under day-time 900- and 2700-lx light conditions. Present findings suggest the amount of light exposure needed to prevent LIMS caused by ordinary nocturnal light in individuals who have a general life rhythm (sleep/wake schedule). These findings may be useful in implementing artificial light environments for humans in, for example, hospitals and underground shopping malls.

Does artificial light-at-night exposure contribute to the worldwide obesity pandemic?

Science.gov (United States)

Rybnikova, N A; Haim, A; Portnov, B A

2016-05-01

Worldwide overweight and obesity rates are on the rise, with about 1 900 billion adults being defined as overweight and about 600 million adults being defined as obese by the World Health Organization (WHO). Increasing exposure to artificial light-at-night (ALAN) may influence body mass, by suppression of melatonin production and disruption of daily rhythms, resulting in physiological or behavioral changes in the human body, and may thus become a driving force behind worldwide overweight and obesity pandemic. We analyzed most recent satellite images of night time illumination, available from the US Defense Meteorological Satellite Program (DMSP), combining them with country-level data on female and male overweight and obesity prevalence rates, reported by the WHO. The study aims to identify and measure the strength of association between ALAN and country-wide overweight and obesity rates, controlling for per capita GDP, level of urbanization, birth rate, food consumption and regional differences. ALAN emerged as a statistically significant and positive predictor of overweight and obesity (t>1.97; Pworldwide. Regional differences in the strength of association between ALAN and excessive body mass are also noted. This study is the first population-level study that confirms the results of laboratory research and cohort studies in which ALAN was found to be a contributing factor to excessive body mass in humans.

Neither artificial light at night, anthropogenic noise nor distance from roads are associated with oxidative status of nestlings in an urban population of songbirds.

Science.gov (United States)

Casasole, Giulia; Raap, Thomas; Costantini, David; AbdElgawad, Hamada; Asard, Han; Pinxten, Rianne; Eens, Marcel

2017-08-01

Increasing urbanization is responsible for road-related pollutants and causes an unprecedented increase in light and noise pollution, with potential detrimental effects for individual animals, communities and ecosystems. These stressors rarely act in isolation but studies dissecting the effects of these multiple stressors are lacking. Moreover, studies on urban stressors have mainly focused on adults, while exposure in early-life may be detrimental but is largely ignored. To fill this important knowledge gap, we studied if artificial light at night, anthropogenic noise and road-related pollution (using distance from roads as a proxy) explain variation in oxidative status in great tit nestlings (Parus major) in an urban population. Artificial light at night, anthropogenic noise and distance from roads were not associated with variation of the nine studied metrics of oxidative status (superoxide dismutase-SOD-, glutathione peroxidase-GPX, catalase-CAT-, non-enzymatic total antioxidant capacity-TAC-, reduced glutathione-GSH-, oxidized glutathione-GSSG-, ratio GSH/GSSG, protein carbonyls and thiobarbituric acid reactive substances-TBARS). Interestingly, for all oxidative status metrics, we found that there was more variation in oxidative status among individuals of the same nest compared to between different nests. We also showed an increase in protein carbonyls and a decrease of the ratio GSH/GSSG as the day advanced, and an increase of GPX when weather conditions deteriorated. Our study suggests that anthropogenic noise, artificial light at night and road-related pollution are not the most important sources of variation in oxidative status in great tit nestlings. It also highlights the importance of considering bleeding time and weather conditions in studies with free-living animals. Copyright © 2017. Published by Elsevier Inc.

Effect of spectral composition of artificial light on the attraction of moths

NARCIS (Netherlands)

Langevelde, van F.; Ettema, J.A.; Donners, M.; Wallis de Vries, M.F.; Groenendijk, D.

2011-01-01

During the last decades, artificial night lighting has increased globally, which largely affected many plant and animal species. So far, current research highlights the importance of artificial light with smaller wavelengths in attracting moths, yet the effect of the spectral composition of

Artificial light at night confounds broad-scale habitat use by migrating birds

NARCIS (Netherlands)

McLaren, J.D.; Buler, J.J.; Schreckengost, T.; Smolinsky, J.A.; Boone, M.; van Loon, E.E.; Dawson, D.K.; Walters, E.L.

With many of the world's migratory bird populations in alarming decline, broad-scale assessments of responses to migratory hazards may prove crucial to successful conservation efforts. Most birds migrate at night through increasingly light-polluted skies. Bright light sources can attract airborne

Dim artificial light at night affects mating, reproductive output, and reactive oxygen species in Drosophila melanogaster.

Science.gov (United States)

McLay, Lucy Katherine; Nagarajan-Radha, Venkatesh; Green, Mark Philip; Jones, Therésa Melanie

2018-05-07

Humans are lighting the night-time environment with ever increasing extent and intensity, resulting in a variety of negative ecological effects in individuals and populations. Effects of light at night on reproductive fitness traits are demonstrated across taxa however, the mechanisms underlying these effects are largely untested. One possible mechanism is that light at night may result in perturbed reactive oxygen species (ROS) and oxidative stress levels. Here, we reared Drosophila melanogaster under either dim (10 lx) light or no light (0 lx) at night for three generations and then compared mating and lifetime oviposition patterns. In a second experiment, we explored whether exposure to light at night treatments resulted in variation in ROS levels in the heads and ovaries of six, 23- and 36-day-old females. We demonstrate that dim light at night affects mating and reproductive output: 10 lx flies courted for longer prior to mating, and female oviposition patterns differed to 0 lx females. ROS levels were lower in the ovaries but not heads, of 10 lx compared with 0 lx females. We suggest that reduced ROS levels may reflect changes in ovarian physiology and cell signaling, which may be related to the differences observed in oviposition patterns. Taken together, our results indicate negative consequences for invertebrates under more stressful, urban, lit conditions and further investigation into the mechanisms driving these changes is warranted to manage invertebrate communities in a brighter future. © 2018 Wiley Periodicals, Inc.

Melatonin: a possible link between the presence of artificial light at night and reductions in biological fitness

Science.gov (United States)

Jones, Therésa M.; Durrant, Joanna; Michaelides, Ellie B.; Green, Mark P.

2015-01-01

The mechanisms underpinning the ecological impacts of the presence of artificial night lighting remain elusive. One suspected underlying cause is that the presence of light at night (LAN) supresses nocturnal production of melatonin, a key driver of biological rhythm and a potent antioxidant with a proposed role in immune function. Here, we briefly review the evidence for melatonin as the link between LAN and changes in behaviour and physiology. We then present preliminary data supporting the potential for melatonin to act as a recovery agent mitigating the negative effects of LAN in an invertebrate. Adult crickets (Teleogryllus commodus), exposed to constant illumination, were provided with dietary melatonin (concentrations: 0, 10 or 100 µg ml−1) in their drinking water. We then compared survival, lifetime fecundity and, over a 4-week period, immune function (haemocyte concentration, lysozyme-like and phenoloxidase (PO) activity). Melatonin supplementation was able only partially to mitigate the detrimental effects of LAN: it did not improve survival or fecundity or PO activity, but it had a largely dose-dependent positive effect on haemocyte concentration and lysozyme-like activity. We discuss the implications of these relationships, as well as the usefulness of invertebrates as model species for future studies that explore the effects of LAN. PMID:25780235

Effects of artificial light at night on human health: A literature review of observational and experimental studies applied to exposure assessment.

Science.gov (United States)

Cho, YongMin; Ryu, Seung-Hun; Lee, Byeo Ri; Kim, Kyung Hee; Lee, Eunil; Choi, Jaewook

2015-01-01

It has frequently been reported that exposure to artificial light at night (ALAN) may cause negative health effects, such as breast cancer, circadian phase disruption and sleep disorders. Here, we reviewed the literature assessing the effects of human exposure to ALAN in order to list the health effects of various aspects of ALAN. Several electronic databases were searched for articles, published through August 2014, related to assessing the effects of exposure to ALAN on human health; these also included the details of experiments on such exposure. A total of 85 articles were included in the review. Several observational studies showed that outdoor ALAN levels are a risk factor for breast cancer and reported that indoor light intensity and individual lighting habits were relevant to this risk. Exposure to artificial bright light during the nighttime suppresses melatonin secretion, increases sleep onset latency (SOL) and increases alertness. Circadian misalignment caused by chronic ALAN exposure may have negative effects on the psychological, cardiovascular and/or metabolic functions. ALAN also causes circadian phase disruption, which increases with longer duration of exposure and with exposure later in the evening. It has also been reported that shorter wavelengths of light preferentially disturb melatonin secretion and cause circadian phase shifts, even if the light is not bright. This literature review may be helpful to understand the health effects of ALAN exposure and suggests that it is necessary to consider various characteristics of artificial light, beyond mere intensity.

Early Birds by Light at Night: Effects of Light Color and Intensity on Daily Activity Patterns in Blue Tits

NARCIS (Netherlands)

de Jong, Maaike; Caro, Samuel P.; Gienapp, Phillip; Spoelstra, Kamiel; Visser, Marcel E.

2017-01-01

Artificial light at night disturbs the daily rhythms of many organisms. To what extent this disturbance depends on the intensity and spectral composition of light remain obscure. Here, we measured daily activity patterns of captive blue tits (Cyanistes caeruleus) exposed to similar intensities of

Dim light at night disrupts molecular circadian rhythms and increases body weight.

Science.gov (United States)

Fonken, Laura K; Aubrecht, Taryn G; Meléndez-Fernández, O Hecmarie; Weil, Zachary M; Nelson, Randy J

2013-08-01

With the exception of high latitudes, life has evolved under bright days and dark nights. Most organisms have developed endogenously driven circadian rhythms that are synchronized to this daily light/dark cycle. In recent years, humans have shifted away from the naturally occurring solar light cycle in favor of artificial and sometimes irregular light schedules produced by electric lighting. Exposure to unnatural light cycles is increasingly associated with obesity and metabolic syndrome; however, the means by which environmental lighting alters metabolism are poorly understood. Thus, we exposed mice to dim light at night and investigated changes in the circadian system and metabolism. Here we report that exposure to ecologically relevant levels of dim (5 lux) light at night altered core circadian clock rhythms in the hypothalamus at both the gene and protein level. Circadian rhythms in clock expression persisted during light at night; however, the amplitude of Per1 and Per2 rhythms was attenuated in the hypothalamus. Circadian oscillations were also altered in peripheral tissues critical for metabolic regulation. Exposure to dimly illuminated, as compared to dark, nights decreased the rhythmic expression in all but one of the core circadian clock genes assessed in the liver. Additionally, mice exposed to dim light at night attenuated Rev-Erb expression in the liver and adipose tissue. Changes in the circadian clock were associated with temporal alterations in feeding behavior and increased weight gain. These results are significant because they provide evidence that mild changes in environmental lighting can alter circadian and metabolic function. Detailed analysis of temporal changes induced by nighttime light exposure may provide insight into the onset and progression of obesity and metabolic syndrome, as well as other disorders involving sleep and circadian rhythm disruption.

Das Ende der Nacht [The End of the Night (2nd enlarged ed.)

Science.gov (United States)

Posch, Thomas; Hölker, Franz; Uhlmann, Thomas; Freyhoff, Anja

2013-09-01

We provide provide an overview of the history of lighting and of the problems arising from artificial lighting. The book covers the following topics: A brief history of light (ch. 1); night and light in cultural history (ch. 2); light pollution in central Europe (ch. 3); Moths and artificial lights (ch. 4); Artificial lighting and birds (ch. 5); Ocean turtles as victims of beach lighting (ch. 6); Moon light as a zeitgeber for the marine fauna (ch. 7); the influence of artificial light at night on freshwater ecology (ch. 8); artificial light and human health (ch. 9); the loss of the night in a 24 hours society (ch. 10).

Traffic Light Detection at Night

DEFF Research Database (Denmark)

Jensen, Morten Bornø; Philipsen, Mark Philip; Bahnsen, Chris

2015-01-01

Traffic light recognition (TLR) is an integral part of any in- telligent vehicle, it must function both at day and at night. However, the majority of TLR research is focused on day-time scenarios. In this paper we will focus on detection of traffic lights at night and evalu- ate the performance...... of three detectors based on heuristic models and one learning-based detector. Evaluation is done on night-time data from the public LISA Traffic Light Dataset. The learning-based detector out- performs the model-based detectors in both precision and recall. The learning-based detector achieves an average...

Dim Light at Night Disrupts Molecular Circadian Rhythms and Affects Metabolism

Science.gov (United States)

Fonken, Laura K.; Aubrecht, Taryn G.; Meléndez-Fernández, O. Hecmarie; Weil, Zachary M.; Nelson, Randy J.

2014-01-01

With the exception of high latitudes, life has evolved under bright days and dark nights. Most organisms have developed endogenously driven circadian rhythms which are synchronized to this daily light/dark cycle. In recent years, humans have shifted away from the naturally occurring solar light cycle in favor of artificial and sometimes irregular light schedules produced by electrical lighting. Exposure to unnatural light cycles is increasingly associated with obesity and metabolic syndrome; however the means by which environmental lighting alters metabolism are poorly understood. Thus, we exposed mice to nighttime light and investigated changes in the circadian system and body weight. Here we report that exposure to ecologically relevant levels of dim (5 lux) light at night attenuate core circadian clock rhythms in the SCN at both the gene and protein level. Moreover, circadian clock rhythms were perturbed in the liver by nighttime light exposure. Changes in the circadian clock were associated with temporal alterations in feeding behavior and increased weight gain. These results are significant because they provide mechanistic evidence for how mild changes in environmental lighting can alter circadian and metabolic function. PMID:23929553

Influence of light intensity and spectral composition of artificial light at night on melatonin rhythm and mRNA expression of gonadotropins in roach Rutilus rutilus.

Science.gov (United States)

Brüning, Anika; Hölker, Franz; Franke, Steffen; Kleiner, Wibke; Kloas, Werner

2018-02-01

In this study we investigated the influence of artificial light at night (ALAN) of different intensities (0, 1, 10, 100 lx) and different colours (blue, green, red) on the daily melatonin rhythm and mRNA expression of gonadotropins in roach Rutilus rutilus, a ubiquitous cyprinid, which occur in standing and moderately flowing freshwater habitats of central Europe. Melatonin concentrations were significantly lowered under nocturnal white light already at 1 lx. Low intensity blue, green and red ALAN lowered the melatonin levels significantly in comparison to a dark control. We conclude that ALAN can disturb melatonin rhythms in roach at very low intensities and at different wavelengths and thus light pollution in urban waters has the potential to impact biological rhythms in fish. However, mRNA expression of gonadotropins was not affected by ALAN during the period of the experiments. Thus, suspected implications of ALAN on reproduction of roach could not be substantiated.

Early Birds by Light at Night: Effects of Light Color and Intensity on Daily Activity Patterns in Blue Tits.

Science.gov (United States)

de Jong, Maaike; Caro, Samuel P; Gienapp, Phillip; Spoelstra, Kamiel; Visser, Marcel E

2017-08-01

Artificial light at night disturbs the daily rhythms of many organisms. To what extent this disturbance depends on the intensity and spectral composition of light remain obscure. Here, we measured daily activity patterns of captive blue tits ( Cyanistes caeruleus) exposed to similar intensities of green, red, or white light at night. Birds advanced their onset of activity in the morning under all light colors but more under red and white light than under green light. Offset of activity was slightly delayed in all light colors. The total activity over a 24-h period did not change but birds moved a part of their daily activity into the night. Since the effect of red and white lights are comparable, we tested the influence of light intensity in a follow-up experiment, where we compared the activity of the birds under different intensities of green and white light only. While in the higher range of intensities, the effects of white and green light were comparable; at lower intensities, green light had a less disturbing effect as compared with white light on daily rhythms in blue tits. Our results show that the extent of this disturbance can be mitigated by modulating the spectral characteristics and intensity of outdoor lighting, which is now feasible through the use of LED lighting.

Artificial Light at Night Reduces Daily Energy Expenditure in Breeding Great Tits (Parus major

Directory of Open Access Journals (Sweden)

Anouk A. M. H. Welbers

2017-05-01

Full Text Available The ecological impact of artificial light at night (ALAN is an increasingly recognized process that accompanies expanding urbanization. Yet, we have limited knowledge on the impact of ALAN on wild species, and on the potential to mitigate any negative effects by using different light sources and colors. In birds, effects of ALAN on activity levels are reported for several species and, hence, their daily energy expenditure (DEE may be affected. DEE is a potent mediator of life-history trade-offs and fitness and thus an important aspect to consider when examining the potential long-term ecological effects of ALAN. Previous work has suggested that birds exposed to ALAN show higher levels of provisioning and nocturnal activity, suggesting that white ALAN increases DEE. Other factors regulating DEE, such as provisioning behavior and food availability, might also respond to ALAN and thus indirectly affect DEE. We tested the hypothesis that ALAN increases DEE using an experimental setup where four previously unlit transects were illuminated with either white, green, or red LED light, or left dark as a control treatment. This setup was replicated in eight locations across the Netherlands. We measured DEE of our focal species, the great tit (Parus major, using a novel doubly labeled water technique that uses breath rather than blood samples. Contrary to our expectations, birds feeding their offspring under white and green ALAN showed lower DEE compared to birds in the control dark treatment. Differences in chick provisioning activity did not explain this result, as neither visit rates nor daily activity timing was affected by light treatment. However, food availability under white and green light was much higher compared to red light and the dark control. This difference strongly suggests that the lower DEE under white and green ALAN sites is a consequence of higher food availability in these treatments. This result shows that there can be positive

Exposure of tropical ecosystems to artificial light at night: Brazil as a case study

Science.gov (United States)

Bennie, Jon; Mantovani, Waldir; Gaston, Kevin J.

2017-01-01

Artificial nighttime lighting from streetlights and other sources has a broad range of biological effects. Understanding the spatial and temporal levels and patterns of this lighting is a key step in determining the severity of adverse effects on different ecosystems, vegetation, and habitat types. Few such analyses have been conducted, particularly for regions with high biodiversity, including the tropics. We used an intercalibrated version of the Defense Meteorological Satellite Program’s Operational Linescan System (DMSP/OLS) images of stable nighttime lights to determine what proportion of original and current Brazilian vegetation types are experiencing measurable levels of artificial light and how this has changed in recent years. The percentage area affected by both detectable light and increases in brightness ranged between 0 and 35% for native vegetation types, and between 0 and 25% for current vegetation (i.e. including agriculture). The most heavily affected areas encompassed terrestrial coastal vegetation types (restingas and mangroves), Semideciduous Seasonal Forest, and Mixed Ombrophilous Forest. The existing small remnants of Lowland Deciduous and Semideciduous Seasonal Forests and of Campinarana had the lowest exposure levels to artificial light. Light pollution has not often been investigated in developing countries but our data show that it is an environmental concern. PMID:28178352

Exposure of tropical ecosystems to artificial light at night: Brazil as a case study.

Science.gov (United States)

Freitas, Juliana Ribeirão de; Bennie, Jon; Mantovani, Waldir; Gaston, Kevin J

2017-01-01

Artificial nighttime lighting from streetlights and other sources has a broad range of biological effects. Understanding the spatial and temporal levels and patterns of this lighting is a key step in determining the severity of adverse effects on different ecosystems, vegetation, and habitat types. Few such analyses have been conducted, particularly for regions with high biodiversity, including the tropics. We used an intercalibrated version of the Defense Meteorological Satellite Program's Operational Linescan System (DMSP/OLS) images of stable nighttime lights to determine what proportion of original and current Brazilian vegetation types are experiencing measurable levels of artificial light and how this has changed in recent years. The percentage area affected by both detectable light and increases in brightness ranged between 0 and 35% for native vegetation types, and between 0 and 25% for current vegetation (i.e. including agriculture). The most heavily affected areas encompassed terrestrial coastal vegetation types (restingas and mangroves), Semideciduous Seasonal Forest, and Mixed Ombrophilous Forest. The existing small remnants of Lowland Deciduous and Semideciduous Seasonal Forests and of Campinarana had the lowest exposure levels to artificial light. Light pollution has not often been investigated in developing countries but our data show that it is an environmental concern.

A night sky model.

Science.gov (United States)

Erpylev, N. P.; Smirnov, M. A.; Bagrov, A. V.

A night sky model is proposed. It includes different components of light polution, such as solar twilight, moon scattered light, zodiacal light, Milky Way, air glow and artificial light pollution. The model is designed for calculating the efficiency of astronomical installations.

Fatal attraction of short-tailed shearwaters to artificial lights.

Directory of Open Access Journals (Sweden)

Airam Rodríguez

Full Text Available Light pollution is increasing around the world and altering natural nightscapes with potential ecological and evolutionary consequences. A severe ecological perturbation caused by artificial lights is mass mortalities of organisms, including seabird fledglings that are attracted to lights at night on their first flights to the sea. Here, we report on the number of fledging short-tailed shearwaters Ardenna tenuirostris found grounded in evening and morning rescue patrols conducted at Phillip Island, Australia, during a 15-year period (1999-2013. We assessed factors affecting numbers of grounded birds and mortality including date, moon phase, wind direction and speed, number of visitors and holiday periods. We also tested experimentally if birds were attracted to lights by turning the lights off on a section of the road. Of 8871 fledglings found, 39% were dead or dying. This mortality rate was 4-8 times higher than reported elsewhere for other shearwater species, probably because searching for fledglings was part of our systematic rescue effort rather than the opportunistic rescue used elsewhere. Thus, it suggests that light-induced mortality of seabirds is usually underestimated. We rescued more birds (dead and alive in peak fledging, moonless and windy nights. Mortality increased through the fledging period, in the mornings and with increased traffic on holiday periods. Turning the road lights off decreased the number of grounded birds (dead and alive. While moon, wind and time are uncontrolled natural constraints, we demonstrated that reduction of light pollution and better traffic management can mitigate artificial light-induced mortality.

Health consequences of electric lighting practices in the modern world : A report on the National Toxicology Program's workshop on shift work at night, artificial light at night, and circadian disruption

NARCIS (Netherlands)

Lunn, Ruth M; Blask, David E; Coogan, Andrew N; Figueiro, Mariana G; Gorman, Michael R; Hall, Janet E; Hansen, Johnni; Nelson, Randy J; Panda, Satchidananda; Smolensky, Michael H; Stevens, Richard G; Turek, Fred W; Vermeulen, Roel; Carreón, Tania; Caruso, Claire C; Lawson, Christina C; Thayer, Kristina A; Twery, Michael J; Ewens, Andrew D; Garner, Sanford C; Schwingl, Pamela J; Boyd, Windy A

2017-01-01

The invention of electric light has facilitated a society in which people work, sleep, eat, and play at all hours of the 24-hour day. Although electric light clearly has benefited humankind, exposures to electric light, especially light at night (LAN), may disrupt sleep and biological processes

Night-Time Light Dynamics during the Iraqi Civil War

Directory of Open Access Journals (Sweden)

Xi Li

2018-06-01

Full Text Available In this study, we analyzed the night-time light dynamics in Iraq over the period 2012–2017 by using Visible Infrared Imaging Radiometer Suite (VIIRS monthly composites. The data quality of VIIRS images was improved by repairing the missing data, and the Night-time Light Ratio Indices (NLRIs, derived from urban extent map and night-time light images, were calculated for different provinces and cities. We found that when the Islamic State of Iraq and Syria (ISIS attacked or occupied a region, the region lost its light rapidly, with the provinces of Al-Anbar, At-Ta’min, Ninawa, and Sala Ad-din losing 63%, 73%, 88%, and 56%, of their night-time light, respectively, between December 2013 and December 2014. Moreover, the light returned after the Iraqi Security Forces (ISF recaptured the region. In addition, we also found that the night-time light in the Kurdish Autonomous Region showed a steady decline after 2014, with the Arbil, Dihok, and As-Sulaymaniyah provinces losing 47%, 18%, and 31% of their night-time light between December 2013 and December 2016 as a result of the economic crisis in the region. The night-time light in Southern Iraq, the region controlled by Iraqi central government, has grown continuously; for example, the night-time light in Al Basrah increased by 75% between December 2013 and December 2017. Regions formerly controlled by ISIS experienced a return of night-time light during 2017 as the ISF retook almost all this territory in 2017. This indicates that as reconstruction began, electricity was re-supplied in these regions. Our analysis shows the night-time light in Iraq is directly linked to the socioeconomic dynamics of Iraq, and demonstrates that the VIIRS monthly night-time light images are an effective data source for tracking humanitarian disasters in that country.

Night lights and regional income inequality in Africa

DEFF Research Database (Denmark)

Mveyange, Anthony Francis

Estimating regional income inequality in Africa has been challenging due to the lack of reliable and consistent sub-national income data. I employ night lights data to circumvent this limitation. I find significant and positive associations between regional inequality visible through night lights...... and income in Africa. Thus, in the absence of income data, we can construct regional inequality proxies using night lights data. Further investigation on the night lights-based regional inequality trends reveals two main findings: first, increasing regional inequality trends between 1992 and 2003; and second......, declining regional inequality trends between 2004 and 2012....

Dim Light at Night Increases Body Mass of Female Mice

OpenAIRE

Aubrecht, Taryn G.; Jenkins, Richelle; Nelson, Randy J.

2014-01-01

During the past century the prevalence of light at night has increased in parallel with obesity rates. Dim light at night (dLAN) increases body mass in male mice. However, the effects of light at night on female body mass remain unspecified. Thus, female mice were exposed to a standard light/dark (LD; 16h light at ~150 lux/8h dark at ~0 lux) cycle or to light/dim light at night (dLAN; 16h light at ~150 lux/8h dim light at ~5 lux) cycles for six weeks. Females exposed to dLAN increased the rat...

Artificial Light at Night Affects Organism Flux across Ecosystem Boundaries and Drives Community Structure in the Recipient Ecosystem

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Alessandro Manfrin

2017-10-01

Full Text Available Artificial light at night (ALAN is a widespread alteration of the natural environment that can affect the functioning of ecosystems. ALAN can change the movement patterns of freshwater animals that move into the adjacent riparian and terrestrial ecosystems, but the implications for local riparian consumers that rely on these subsidies are still unexplored. We conducted a 2-year field experiment to quantify changes of freshwater-terrestrial linkages by installing streetlights in a previously light-naïve riparian area adjacent to an agricultural drainage ditch. We compared the abundance and community composition of emerging aquatic insects, flying insects, and ground-dwelling arthropods with an unlit control site. Comparisons were made within and between years using two-way generalized least squares (GLS model and a BACI design (Before-After Control-Impact. Aquatic insect emergence, the proportion of flying insects that were aquatic in origin, and the total abundance of flying insects all increased in the ALAN-illuminated area. The abundance of several night-active ground-dwelling predators (Pachygnatha clercki, Trochosa sp., Opiliones increased under ALAN and their activity was extended into the day. Conversely, the abundance of nocturnal ground beetles (Carabidae decreased under ALAN. The changes in composition of riparian predator and scavenger communities suggest that the increase in aquatic-to-terrestrial subsidy flux may cascade through the riparian food web. The work is among the first studies to experimentally manipulate ALAN using a large-scale field experiment, and provides evidence that ALAN can affect processes that link adjacent ecosystems. Given the large number of streetlights that are installed along shorelines of freshwater bodies throughout the globe, the effects could be widespread and represent an underestimated source of impairment for both aquatic and riparian systems.

Chronic exposure to dim light at night suppresses immune responses in Siberian hamsters.

Science.gov (United States)

Bedrosian, Tracy A; Fonken, Laura K; Walton, James C; Nelson, Randy J

2011-06-23

Species have been adapted to specific niches optimizing survival and reproduction; however, urbanization by humans has dramatically altered natural habitats. Artificial light at night (LAN), termed 'light pollution', is an often overlooked, yet increasing disruptor of habitats, which perturbs physiological processes that rely on precise light information. For example, LAN alters the timing of reproduction and activity in some species, which decreases the odds of successful breeding and increases the threat of predation for these individuals, leading to reduced fitness. LAN also suppresses immune function, an important proxy for survival. To investigate the impact of LAN in a species naive to light pollution in its native habitat, immune function was examined in Siberian hamsters derived from wild-caught stock. After four weeks exposure to dim LAN, immune responses to three different challenges were assessed: (i) delayed-type hypersensitivity (DTH), (ii) lipopolysaccharide-induced fever, and (iii) bactericide activity of blood. LAN suppressed DTH response and reduced bactericide activity of blood after lipopolysaccharide treatment, in addition to altering daily patterns of locomotor activity, suggesting that human encroachment on habitats via night-time lighting may inadvertently compromise immune function and ultimately fitness.

Light Pollution Awareness through Globe at Night & IYL2015

Science.gov (United States)

Walker, Constance E.

2015-01-01

The International Astronomical Union (IAU) will be coordinating extensive activities to raise awareness of light pollution through running the Cosmic Light theme of the International Year of Light (IYL2015) and by partnering in particular with the popular Globe at Night program.Globe at Night (www.globeatnight.org) is an international campaign to raise public awareness of the impact of light pollution by having people measure night-sky brightness and submit observations in real-time with smart phone or later with a computer. In 2015, Globe at Night will run for 10-nights each month, an hour after sunset til before the Moon rises. Students can use the data to monitor levels of light pollution around the world, as well as understand light pollution's effects on energy consumption, plants, wildlife, human health and our ability to enjoy a starry night sky.Since its inception in 2006, more than 115,000 measurements from 115 countries have been reported. The last 9 years of data can be explored with Globe at Night's interactive world map or with the 'map app' to view a particular area. A spreadsheet of the data is downloadable from any year. One can compare Globe at Night data with a variety of other databases to see, for example, how light pollution affects the foraging habits of bats.To encourage public participation in Globe at Night during IYL2015, each month will target an area of the world that habitually contributes during that time. Special concerns for how light pollution affects that area and solutions will be featured on the Globe at Night website (www.globeatnight.org), through its Facebook page, in its newsletter or in the 365DaysofAstronomy.org podcasts.Twice during IYL there will be a global Flash Mob event, one on Super Pi Day (March 14, 2015) and a second in mid-September, where the public will be invited to take night-sky brightness measurements en masse. In April, the International Dark-Sky Week hosted by the International Dark-Sky Association will be

Light at Night Markup Language (LANML): XML Technology for Light at Night Monitoring Data

Science.gov (United States)

Craine, B. L.; Craine, E. R.; Craine, E. M.; Crawford, D. L.

2013-05-01

Light at Night Markup Language (LANML) is a standard, based upon XML, useful in acquiring, validating, transporting, archiving and analyzing multi-dimensional light at night (LAN) datasets of any size. The LANML standard can accommodate a variety of measurement scenarios including single spot measures, static time-series, web based monitoring networks, mobile measurements, and airborne measurements. LANML is human-readable, machine-readable, and does not require a dedicated parser. In addition LANML is flexible; ensuring future extensions of the format will remain backward compatible with analysis software. The XML technology is at the heart of communicating over the internet and can be equally useful at the desktop level, making this standard particularly attractive for web based applications, educational outreach and efficient collaboration between research groups.

Light at Night and Breast Cancer Risk Among California Teachers

Science.gov (United States)

Hurley, Susan; Goldberg, Debbie; Nelson, David; Hertz, Andrew; Horn-Ross, Pamela L.; Bernstein, Leslie; Reynolds, Peggy

2014-01-01

Background There is convincing evidence that circadian disruption mediated by exposure to light at night promotes mammary carcinogenesis in rodents. The role that light at night plays in human breast cancer etiology remains unknown. We evaluated the relationship between estimates of indoor and outdoor light at night and the risk of breast cancer among members of the California Teachers Study. Methods Indoor light-at-night estimates were based on questionnaire data regarding sleep habits and use of night time lighting while sleeping. Estimates of outdoor light at night were derived from imagery data obtained from the U.S. Defense Meteorological Satellite Program assigned to geocoded addresses of study participants. Analyses were conducted among 106,731 California Teachers Study members who lived in California, had no prior history of breast cancer, and provided information on lighting while sleeping. 5,095 cases of invasive breast cancer diagnosed 1995–2010 were identified via linkage to the California Cancer Registry. We used age-stratified Cox proportional hazard models to calculate hazard ratios (HRs) with 95% confidence intervals (CIs), adjusting for breast cancer risk factors and neighborhood urbanization and socioeconomic class. Results An increased risk was found for women living in areas with the highest quintile of outdoor light at night exposure estimates (HR=1.12 [95% CI=1.00 – 1.26], test for trend, P=0.06). While more pronounced among premenopausal women (HR=1.34 [95% CI=1.07 – 1.69], test for trend, P=0.04), the associations did not differ statistically by menopausal status (test for interaction, P=0.34). Conclusions Women living in areas with high levels of ambient light at night may be at an increased risk of breast cancer. Future studies that integrate quantitative measurements of indoor and outdoor light at night are warranted. PMID:25061924

Modeling the effects of phosphor converted LED lighting to the night sky of the Haleakala Observatory, Hawaii

Science.gov (United States)

Aubé, M.; Simoneau, A.; Wainscoat, R.; Nelson, L.

2018-05-01

The goal of this study is to evaluate the current level of light pollution in the night sky at the Haleakala Observatory on the island of Maui in Hawaii. This is accomplished with a numerical model that was tested in the first International Dark Sky Reserve located in Mont-Mégantic National Park in Canada. The model uses ground data on the artificial light sources present in the region of study, geographical data, and remotely sensed data for: 1) the nightly upward radiance; 2) the terrain elevation; and, 3) the ground spectral reflectance of the region. The results of the model give a measure of the current state of the sky spectral radiance at the Haleakala Observatory. Then, using the current state as a reference point, multiple light conversion plans are elaborated and evaluated using the model. We can thus estimate the expected impact of each conversion plan on the night sky radiance spectrum. A complete conversion to white (LEDs) with (CCT) of 4000K and 3000K are contrasted with a conversion using (PC) amber (LEDs). We include recommendations concerning the street lamps to be used in sensitive areas like the cities of Kahului and Kihei and suggest best lighting practices related to the color of lamps used at night.

Mapping lightscapes: spatial patterning of artificial lighting in an urban landscape.

Science.gov (United States)

Hale, James D; Davies, Gemma; Fairbrass, Alison J; Matthews, Thomas J; Rogers, Christopher D F; Sadler, Jon P

2013-01-01

Artificial lighting is strongly associated with urbanisation and is increasing in its extent, brightness and spectral range. Changes in urban lighting have both positive and negative effects on city performance, yet little is known about how its character and magnitude vary across the urban landscape. A major barrier to related research, planning and governance has been the lack of lighting data at the city extent, particularly at a fine spatial resolution. Our aims were therefore to capture such data using aerial night photography and to undertake a case study of urban lighting. We present the finest scale multi-spectral lighting dataset available for an entire city and explore how lighting metrics vary with built density and land-use. We found positive relationships between artificial lighting indicators and built density at coarse spatial scales, whilst at a local level lighting varied with land-use. Manufacturing and housing are the primary land-use zones responsible for the city's brightly lit areas, yet manufacturing sites are relatively rare within the city. Our data suggests that efforts to address light pollution should broaden their focus from residential street lighting to include security lighting within manufacturing areas.

Dim light at night increases body mass of female mice.

Science.gov (United States)

Aubrecht, Taryn G; Jenkins, Richelle; Nelson, Randy J

2015-05-01

During the past century, the prevalence of light at night has increased in parallel with obesity rates. Dim light at night (dLAN) increases body mass in male mice. However, the effects of light at night on female body mass remain unspecified. Thus, female mice were exposed to a standard light/dark (LD; 16 h light at ∼150 lux/8 h dark at ∼0 lux) cycle or to light/dim light at night (dLAN; 16 h light at ∼150 lux/8 h dim light at ∼5 lux) cycles for six weeks. Females exposed to dLAN increased the rate of change in body mass compared to LD mice despite reduced total food intake during weeks five and six, suggesting that dLAN disrupted circadian rhythms resulting in deranged metabolism.

Disruption of Circadian Rhythms by Light During Day and Night.

Science.gov (United States)

Figueiro, Mariana G

2017-06-01

This study aims to discuss possible reasons why research to date has not forged direct links between light at night, acute melatonin suppression or circadian disruption, and risks for disease. Data suggest that irregular light-dark patterns or light exposures at the wrong circadian time can lead to circadian disruption and disease risks. However, there remains an urgent need to: (1) specify light stimulus in terms of circadian rather than visual response; (2) when translating research from animals to humans, consider species-specific spectral and absolute sensitivities to light; (3) relate the characteristics of photometric measurement of light at night to the operational characteristics of the circadian system; and (4) examine how humans may be experiencing too little daytime light, not just too much light at night. To understand the health effects of light-induced circadian disruption, we need to measure and control light stimulus during the day and at night.

Green Grape Detection and Picking-Point Calculation in a Night-Time Natural Environment Using a Charge-Coupled Device (CCD Vision Sensor with Artificial Illumination

Directory of Open Access Journals (Sweden)

Juntao Xiong

2018-03-01

Full Text Available Night-time fruit-picking technology is important to picking robots. This paper proposes a method of night-time detection and picking-point positioning for green grape-picking robots to solve the difficult problem of green grape detection and picking in night-time conditions with artificial lighting systems. Taking a representative green grape named Centennial Seedless as the research object, daytime and night-time grape images were captured by a custom-designed visual system. Detection was conducted employing the following steps: (1 The RGB (red, green and blue. Color model was determined for night-time green grape detection through analysis of color features of grape images under daytime natural light and night-time artificial lighting. The R component of the RGB color model was rotated and the image resolution was compressed; (2 The improved Chan–Vese (C–V level set model and morphological processing method were used to remove the background of the image, leaving out the grape fruit; (3 Based on the character of grape vertical suspension, combining the principle of the minimum circumscribed rectangle of fruit and the Hough straight line detection method, straight-line fitting for the fruit stem was conducted and the picking point was calculated using the stem with an angle of fitting line and vertical line less than 15°. The visual detection experiment results showed that the accuracy of grape fruit detection was 91.67% and the average running time of the proposed algorithm was 0.46 s. The picking-point calculation experiment results showed that the highest accuracy for the picking-point calculation was 92.5%, while the lowest was 80%. The results demonstrate that the proposed method of night-time green grape detection and picking-point calculation can provide technical support to the grape-picking robots.

Dim light at night does not disrupt timing or quality of sleep in mice.

Science.gov (United States)

Borniger, Jeremy C; Weil, Zachary M; Zhang, Ning; Nelson, Randy J

2013-10-01

Artificial nighttime illumination has recently become commonplace throughout the world; however, in common with other animals, humans have not evolved in the ecological context of chronic light at night. With prevailing evidence linking the circadian, endocrine, immune, and metabolic systems, understanding these relationships is important to understanding the etiology and progression of several diseases. To eliminate the covariate of sleep disruption in light at night studies, researchers often use nocturnal animals. However, the assumption that light at night does not affect sleep in nocturnal animals remains unspecified. To test the effects of light at night on sleep, we maintained Swiss-Webster mice in standard light/dark (LD) or dim light at night (DLAN) conditions for 8-10 wks and then measured electroencephalogram (EEG) and electromyogram (EMG) biopotentials via wireless telemetry over the course of two consecutive days to determine differences in sleep timing and homeostasis. Results show no statistical differences in total percent time, number of episodes, maximum or average episode durations in wake, slow-wave sleep (SWS), or rapid eye movement (REM) sleep. No differences were evident in SWS delta power, an index of sleep drive, between groups. Mice kept in DLAN conditions showed a relative increase in REM sleep during the first few hours after the dark/light transition. Both groups displayed normal 24-h circadian rhythms as measured by voluntary running wheel activity. Groups did not differ in body mass, but a marked negative correlation of body mass with percent time spent awake and a positive correlation of body mass with time spent in SWS was evident. Elevated body mass was also associated with shorter maximum wake episode durations, indicating heavier animals had more trouble remaining in the wake vigilance state for extended periods of time. Body mass did not correlate with activity levels, nor did activity levels correlate with time spent in

Exposure to dim light at night during early development increases adult anxiety-like responses.

Science.gov (United States)

Borniger, Jeremy C; McHenry, Zachary D; Abi Salloum, Bachir A; Nelson, Randy J

2014-06-22

Early experiences produce effects that may persist throughout life. Therefore, to understand adult phenotype, it is important to investigate the role of early environmental stimuli in adult behavior and health. Artificial light at night (LAN) is an increasingly common phenomenon throughout the world. However, animals, including humans, evolved under dark night conditions. Many studies have revealed affective, immune, and metabolic alterations provoked by aberrant light exposure and subsequent circadian disruption. Pups are receptive to entraining cues from the mother and then light early during development, raising the possibility that the early life light environment may influence subsequent behavior. Thus, to investigate potential influences of early life exposure to LAN on adult phenotype, we exposed mice to dim (~5 lux; full spectrum white light) or dark (~0 lux) nights pre- and/or postnatally. After weaning at 3 weeks of age, all mice were maintained in dark nights until adulthood (9 weeks of age) when behavior was assessed. Mice exposed to dim light in early life increased anxiety-like behavior and fearful responses on the elevated plus maze and passive avoidance tests. These mice also displayed reduced growth rates, which ultimately normalized during adolescence. mRNA expression of brain derived neurotrophic factor (BDNF), a neurotrophin previously linked to early life environment and adult phenotype, was not altered in the prefrontal cortex or hippocampus by early life LAN exposure. Serum corticosterone concentrations were similar between groups at weaning, suggesting that early life LAN does not elicit a long-term physiologic stress response. Dim light exposure did not influence behavior on the open field, novel object, sucrose anhedonia, or forced swim tests. Our data highlight the potential deleterious consequences of low levels of light during early life to development and subsequent behavior. Whether these changes are due to altered maternal behavior

Dim light at night provokes depression-like behaviors and reduces CA1 dendritic spine density in female hamsters.

Science.gov (United States)

Bedrosian, Tracy A; Fonken, Laura K; Walton, James C; Haim, Abraham; Nelson, Randy J

2011-08-01

The prevalence of major depression has increased in recent decades; however, the underlying causes of this phenomenon remain unspecified. One environmental change that has coincided with elevated rates of depression is increased exposure to artificial light at night. Shift workers and others chronically exposed to light at night are at increased risk of mood disorders, suggesting that nighttime illumination may influence brain mechanisms mediating affect. We tested the hypothesis that exposure to dim light at night may impact affective responses and alter morphology of hippocampal neurons. Ovariectomized adult female Siberian hamsters (Phodopus sungorus) were housed for 8 weeks in either a light/dark cycle (LD) or a light/dim light cycle (DM), and then behavior was assayed. DM-hamsters displayed more depression-like responses in the forced swim and the sucrose anhedonia tests compared with LD-hamsters. Conversely, in the elevated plus maze DM-hamsters reduced anxiety-like behaviors. Brains from the same animals were processed using the Golgi-Cox method and hippocampal neurons within CA1, CA3, and the dentate gyrus were analyzed for morphological characteristics. In CA1, DM-hamsters significantly reduced dendritic spine density on both apical and basilar dendrites, an effect which was not mediated by baseline cortisol, as concentrations were equivalent between groups. These results demonstrate dim light at night is sufficient to reduce synaptic spine connections to CA1. Importantly, the present results suggest that night-time low level illumination, comparable to levels that are pervasive in North America and Europe, may contribute to the increasing prevalence of mood disorders. Copyright © 2011 Elsevier Ltd. All rights reserved.

Dark nights reverse metabolic disruption caused by dim light at night.

Science.gov (United States)

Fonken, L K; Weil, Z M; Nelson, R J

2013-06-01

The increasing prevalence of obesity and related metabolic disorders coincides with increasing exposure to light at night. Previous studies report that mice exposed to dim light at night (dLAN) develop symptoms of metabolic syndrome. This study investigated whether mice returned to dark nights after dLAN exposure recover metabolic function. Male Swiss-Webster mice were assigned to either: standard light-dark (LD) conditions for 8 weeks (LD/LD), dLAN for 8 weeks (dLAN/dLAN), LD for 4 weeks followed by 4 weeks of dLAN (LD/dLAN), and dLAN for 4 weeks followed by 4 weeks of LD (dLAN/LD). After 4 weeks in their respective lighting conditions both groups initially placed in dLAN increased body mass gain compared to LD mice. Half of the dLAN mice (dLAN/LD) were then transferred to LD and vice versa (LD/dLAN). Following the transfer dLAN/dLAN and LD/dLAN mice gained more weight than LD/LD and dLAN/LD mice. At the conclusion of the study dLAN/LD mice did not differ from LD/LD mice with respect to weight gain and had lower fat pad mass compared to dLAN/dLAN mice. Compared to all other groups dLAN/dLAN mice decreased glucose tolerance as indicated by an intraperitoneal glucose tolerance test at week 7, indicating that dLAN/LD mice recovered glucose metabolism. dLAN/dLAN mice also increased MAC1 mRNA expression in peripheral fat as compared to both LD/LD and dLAN/LD mice, suggesting peripheral inflammation is induced by dLAN, but not sustained after return to LD. These results suggest that re-exposure to dark nights ameliorates metabolic disruption caused by dLAN exposure. Copyright © 2013 The Obesity Society.

LAN MAP: An Innovative Airborne Light at Night Mapping Project

Science.gov (United States)

Craine, Eric R.; Craine, B. L.; Craine, E. M.; Craine, P. R.

2013-01-01

Widespread installation of inefficient and misdirected artificial light at night (LAN) has led to increasing concerns about light pollution and its impact, not only on astronomical facilities but larger communities as well. Light pollution impacts scientific research, environmental ecosystems, human health, and quality of life. In recent years, the public policy response to light pollution has included formulation of government codes to regulate lighting design and installation. Various environmental groups now include light pollution among their rallying themes to protest both specific and general developments. The latter efforts are often conducted in the absence of any quantitative data and are frequently charged by emotion rather than reason. To bring some scientific objectivity, and quantitative data, to these discussions, we have developed a suite of tools for simultaneous photometric measurements and temporal monitoring of both local communities and the sky overhead. We have also developed novel protocols for the use of these tools, including a triad of airborne, ground mobile, and ground static photometric surveys. We present a summary of these tools and protocols, with special emphasis on the airborne systems, and discuss baseline and follow-up measurements of LAN environments in the vicinity of numerous observatories in Arizona, the home of the initial LAN MAP surveys.

Transient anhedonia phenotype and altered circadian timing of behaviour during night-time dim light exposure in Per3-/- mice, but not wildtype mice.

Science.gov (United States)

Martynhak, Bruno Jacson; Hogben, Alexandra L; Zanos, Panos; Georgiou, Polymnia; Andreatini, Roberto; Kitchen, Ian; Archer, Simon N; von Schantz, Malcolm; Bailey, Alexis; van der Veen, Daan R

2017-01-10

Industrialisation greatly increased human night-time exposure to artificial light, which in animal models is a known cause of depressive phenotypes. Whilst many of these phenotypes are 'direct' effects of light on affect, an 'indirect' pathway via altered sleep-wake timing has been suggested. We have previously shown that the Period3 gene, which forms part of the biological clock, is associated with altered sleep-wake patterns in response to light. Here, we show that both wild-type and Per3 -/- mice showed elevated levels of circulating corticosterone and increased hippocampal Bdnf expression after 3 weeks of exposure to dim light at night, but only mice deficient for the PERIOD3 protein (Per3 -/- ) exhibited a transient anhedonia-like phenotype, observed as reduced sucrose preference, in weeks 2-3 of dim light at night, whereas WT mice did not. Per3 -/- mice also exhibited a significantly smaller delay in behavioural timing than WT mice during weeks 1, 2 and 4 of dim light at night exposure. When treated with imipramine, neither Per3 -/- nor WT mice exhibited an anhedonia-like phenotype, and neither genotypes exhibited a delay in behavioural timing in responses to dLAN. While the association between both Per3 -/- phenotypes remains unclear, both are alleviated by imipramine treatment during dim night-time light.

Global Night-Time Lights for Observing Human Activity

Science.gov (United States)

Hipskind, Stephen R.; Elvidge, Chris; Gurney, K.; Imhoff, Mark; Bounoua, Lahouari; Sheffner, Edwin; Nemani, Ramakrishna R.; Pettit, Donald R.; Fischer, Marc

2011-01-01

We present a concept for a small satellite mission to make systematic, global observations of night-time lights with spatial resolution suitable for discerning the extent, type and density of human settlements. The observations will also allow better understanding of fine scale fossil fuel CO2 emission distribution. The NASA Earth Science Decadal Survey recommends more focus on direct observations of human influence on the Earth system. The most dramatic and compelling observations of human presence on the Earth are the night light observations taken by the Defence Meteorological System Program (DMSP) Operational Linescan System (OLS). Beyond delineating the footprint of human presence, night light data, when assembled and evaluated with complementary data sets, can determine the fine scale spatial distribution of global fossil fuel CO2 emissions. Understanding fossil fuel carbon emissions is critical to understanding the entire carbon cycle, and especially the carbon exchange between terrestrial and oceanic systems.

Student Project and Curriculum Based on Light at Night Data Collection

Science.gov (United States)

Craine, Erin M.; DeBenedetti, Jennifer C.

2012-05-01

There is a growing movement in the educational field to promote science, technology, engineering and math studies, stemming from a concern about waning understanding and interest among K-12 students in these topics. STEM Laboratory, Inc. (STEM) has developed a Sky Brightness Meter (SBM) that can be used with ease yet produces complex information relating to light at night monitoring. STEM sees the SBM and its corresponding data archive as a means to involve students in projects that relate to scientific method exploration, makes science more accessible, and encourages a life long appreciation and understanding of scientific endeavors. In this paper we present an example of a project template that could be used by students studying effects of artificial light on sky brightness. STEM has developed several outreach lessons aligned with the National Common Core Curriculum, Systems Thinking concepts and local standards to be implemented in classrooms or independent youth organizations.

Night work, light exposure and melatonin on work days and days off.

Science.gov (United States)

Daugaard, Stine; Garde, Anne Helene; Bonde, Jens Peter Ellekilde; Christoffersen, Jens; Hansen, Äse Marie; Markvart, Jakob; Schlünssen, Vivi; Skene, Debra J; Vistisen, Helene Tilma; Kolstad, Henrik A

2017-01-01

We aimed to examine the effects of night work on salivary melatonin concentration during and subsequent to night work and the mediating role of light. We included 254 day workers and 87 night workers who were followed during 322 work days and 301 days off work. Each day was defined as the 24 hour period starting from the beginning of a night shift or from waking in the mornings with day work and days off. Light levels were recorded and synchronized with diary information (start and end of sleep and work). On average, participants provided four saliva samples per day, and these were analyzed for melatonin concentration by liquid chromatography tandem mass spectrometry (LC-MS/MS). Differences between day and night workers on work days and days off were assessed with multilevel regression models with melatonin concentration as the primary outcome. All models were stratified or adjusted by time of day. For light exposure, we estimated the total, direct and indirect effects of night work on melatonin concentrations obtaining 95% confidence intervals through bootstrapping. On work days, night workers showed 15% lower salivary melatonin concentrations compared with day workers (-15.0%; 95% CI: -31.4%; 5.2%). During the night, light exposure mediated a melatonin suppression of approximately 6% (-5.9%, 95% CI: -10.2%; -1.5%). No mediating effect of light was seen during the day time. On days off, we observed no difference in melatonin concentrations between day and night workers. These findings are in accordance with a transient and partly light-mediated effect of night work on melatonin production.

Modal evaluation of the anthropogenic night sky brightness at arbitrary distances from a light source

International Nuclear Information System (INIS)

Bará, Salvador; Ribas, Salvador J; Kocifaj, Miroslav

2015-01-01

The artificial emissions of light contribute to a high extent to the observed brightness of the night sky in many places of the world. Determining the all-sky radiance of anthropogenic origin requires solving the radiative transfer equation for ground-level light sources, generally resorting to a double-scattering approximation in order to account for the observed radiance patterns with a reasonable degree of accuracy. Since the all-sky radiance distribution produced by an elementary light source depends on the distance to the observer in a way that is not immediately obvious, the contributions of sources located at different distances have to be computed on an individual basis, solving for each one the corresponding scattering integrals. In this paper we show that these calculations may be significantly alleviated by using a modal approach, whereby the hemispheric night-sky radiance is expanded in terms of a convenient basis of two-dimensional (2D) orthogonal functions. Since the modal coefficients of this expansion do vary smoothly with the distance to the observer, the all-sky brightness distributions produced by light sources located at arbitrary intermediate distances can be efficiently estimated by interpolation, provided that the coefficients at a discrete set of distances are accurately determined beforehand. (paper)

Experimental illumination of natural habitat-an experimental set-up to assess the direct and indirect ecological consequences of artificial light of different spectral composition

NARCIS (Netherlands)

Spoelstra, Kamiel; van Grunsven, Roy H. A.; Donners, Maurice; Gienapp, Phillip; Huigens, Martinus E.; Slaterus, Roy; Berendse, Frank; Visser, Marcel E.; Veenendaal, Elmar

2015-01-01

Artificial night-time illumination of natural habitats has increased dramatically over the past few decades. Generally, studies that assess the impact of artificial light on various species in the wild make use of existing illumination and are therefore correlative. Moreover, studies mostly focus on

Transient anhedonia phenotype and altered circadian timing of behaviour during night-time dim light exposure in Per3−/− mice, but not wildtype mice

Science.gov (United States)

Martynhak, Bruno Jacson; Hogben, Alexandra L.; Zanos, Panos; Georgiou, Polymnia; Andreatini, Roberto; Kitchen, Ian; Archer, Simon N.; von Schantz, Malcolm; Bailey, Alexis; van der Veen, Daan R.

2017-01-01

Industrialisation greatly increased human night-time exposure to artificial light, which in animal models is a known cause of depressive phenotypes. Whilst many of these phenotypes are ‘direct’ effects of light on affect, an ‘indirect’ pathway via altered sleep-wake timing has been suggested. We have previously shown that the Period3 gene, which forms part of the biological clock, is associated with altered sleep-wake patterns in response to light. Here, we show that both wild-type and Per3−/− mice showed elevated levels of circulating corticosterone and increased hippocampal Bdnf expression after 3 weeks of exposure to dim light at night, but only mice deficient for the PERIOD3 protein (Per3−/−) exhibited a transient anhedonia-like phenotype, observed as reduced sucrose preference, in weeks 2–3 of dim light at night, whereas WT mice did not. Per3−/− mice also exhibited a significantly smaller delay in behavioural timing than WT mice during weeks 1, 2 and 4 of dim light at night exposure. When treated with imipramine, neither Per3−/− nor WT mice exhibited an anhedonia-like phenotype, and neither genotypes exhibited a delay in behavioural timing in responses to dLAN. While the association between both Per3−/− phenotypes remains unclear, both are alleviated by imipramine treatment during dim night-time light. PMID:28071711

Controlled patterns of daytime light exposure improve circadian adjustment in simulated night work.

Science.gov (United States)

Dumont, Marie; Blais, Hélène; Roy, Joanie; Paquet, Jean

2009-10-01

Circadian misalignment between the endogenous circadian signal and the imposed rest-activity cycle is one of the main sources of sleep and health troubles in night shift workers. Timed bright light exposure during night work can reduce circadian misalignment in night workers, but this approach is limited by difficulties in incorporating bright light treatment into most workplaces. Controlled light and dark exposure during the daytime also has a significant impact on circadian phase and could be easier to implement in real-life situations. The authors previously described distinctive light exposure patterns in night nurses with and without circadian adaptation. In the present study, the main features of these patterns were used to design daytime light exposure profiles. Profiles were then tested in a laboratory simulation of night work to evaluate their efficacy in reducing circadian misalignment in night workers. The simulation included 2 day shifts followed by 4 consecutive night shifts (2400-0800 h). Healthy subjects (15 men and 23 women; 20-35 years old) were divided into 3 groups to test 3 daytime light exposure profiles designed to produce respectively a phase delay (delay group, n=12), a phase advance (advance group, n=13), or an unchanged circadian phase (stable group, n=13). In all 3 groups, light intensity was set at 50 lux during the nights of simulated night work. Salivary dim light melatonin onset (DLMO) showed a significant phase advance of 2.3 h (+/-1.3 h) in the advance group and a significant phase delay of 4.1 h (+/-1.3 h) in the delay group. The stable group showed a smaller but significant phase delay of 1.7 h (+/-1.6 h). Urinary 6-sulfatoxymelatonin (aMT6s) acrophases were highly correlated to salivary DLMOs. Urinary aMT6s acrophases were used to track daily phase shifts. They showed that phase shifts occurred rapidly and differed between the 3 groups by the 3rd night of simulated night work. These results show that significant phase shifts can

Dawn song in natural and artificial continuous day: Light pollution affects songbirds at high latitudes.

Science.gov (United States)

Derryberry, Elizabeth P

2017-10-01

In Focus: Da Silva, A., & Kempenaers, B. (2017). Singing from North to South: Latitudinal variation in timing of dawn singing under natural and artificial light conditions. Journal of Animal Ecology, 86, 1286-1297. doi: 10.1111/1365-2656.12739 Satellite images of the world at night show bright dots connected by glowing lines crisscrossing the globe. As these connect-the-dots become brighter and expand into more and more remote regions, much of the flora and fauna of the world are experiencing evolutionarily unprecedented levels of light at night. Light cues are essential to most physiological and behavioural processes, and so the need to measure the effects of light pollution on these processes is critical. In this issue, Da Silva and Kempenaers take on this task using an important reproductive behaviour in songbirds-dawn song. The geographic, temporal and taxonomic breadth of sampling in this study allows for a close examination of a potentially complex interaction between light pollution and natural variation in the behaviour of dawn singing across latitude, season and species. Their extensive dataset highlights complexity in how songbirds respond to light pollution. Although light pollution has a strong effect on the timing of dawn song, not all songbirds respond the same way to light pollution, and the effects of light pollution vary with changes in natural light levels. Early dawn singers show more flexibility in the timing of dawn song across the season and across latitudes than late dawn singers, and also appear less affected by light pollution at high latitudes than are late dawn singers. These findings suggest that not all songbirds are responding to artificial continuous daylight as they do to natural continuous daylight, highlighting the general need to measure the fitness effects of light pollution. © 2017 The Author. Journal of Animal Ecology © 2017 British Ecological Society.

Depressive-like behavior is elevated among offspring of parents exposed to dim light at night prior to mating.

Science.gov (United States)

Cissé, Yasmine M; Russart, Kathryn L G; Nelson, Randy J

2017-09-01

Rates of major depressive disorder (MDD) have steadily increased over the past 50 years. Many factors have been implicated in the etiology of depressive disorders and environmental influences are being increasingly recognized. The increase in depression rates has coincided with increased artificial nighttime lighting. Exposure to light at night (LAN) has been associated with increased depressive-like behavior in rodents and decreased mood in humans. However, relatively little is known on the multigenerational effects of dLAN on affect. In this study, we exposed adult male and female Siberian hamsters (Phodopus sungorus) to either DARK (0lx) or dim LAN (5lx) for 9 weeks, then paired animals in a full factorial design; all animals were thereafter housed in dark nights. Offspring were gestated and reared in dark nights, then tested in adulthood for depressive-like behaviors and hippocampal expression of glucocorticoid (GR) and melatonin (MT1) receptor expression. Maternal exposure to dLAN decreased sucrose preference, time to first float bout in the Porsolt swim test, and GR expression in the hippocampus. Paternal exposure to dLAN increased time spent floating, and increased hippocampal GR expression. Overall, our results suggest that chronic exposure of parents to light at night has multigenerational effects on offspring depressive-like behavior. If these results pertain to humans, then our data suggest that LAN may contribute to the rapidly rising rates of major depressive disorder in industrialized and developing countries. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of housing rats in dim light or long nights on heart rate.

Science.gov (United States)

Azar, Toni A; Sharp, Jody L; Lawson, David M

2008-07-01

Housing laboratory animals under lighting conditions that more closely mimic the natural environment may improve their wellbeing. This study examined the effects of dim light or a long-night photocycle on resting heart rate (HR) of rats and their HR responses to acute procedures. Male and female Sprague-Dawley (SD) and spontaneously hypertensive (SHR) rats, instrumented with radiotelemetry transmitters and housed individually under a 12:12-h light:dark photocycle with 10 lx illumination (dim light) or under an 8:16-h light:dark photocycle with 200 lx illumination (long nights), were compared with control rats individually housed under a 12:12-h light:dark photocycle with 200 lx illumination. Dim light and long nights significantly reduced the HR of undisturbed SD and SHR male and SHR female rats during the day and at night; however, the HR of undisturbed SD females was not affected. When rats were subjected acutely to husbandry, experimental, or stressful procedures, dim light or long nights (or both) reduced HR responses to some procedures, did not alter responses to others, and increased responses to yet other procedures. The pattern of effects varied between strains and between male and female rats. Because basal HR was reduced when rats were housed under 10 lx illumination or an 8:16-h light:dark photocycle, we concluded that housing rats under 12:12-h light:dark, 200 lx ambient light conditions was potentially stressful, We also concluded that dim light or long nights did not uniformly reduce the increased HR responses induced by acute procedures.

Dim light at night disrupts the short-day response in Siberian hamsters.

Science.gov (United States)

Ikeno, Tomoko; Weil, Zachary M; Nelson, Randy J

2014-02-01

Photoperiodic regulation of physiology, morphology, and behavior is crucial for many animals to survive seasonally variable conditions unfavorable for reproduction and survival. The photoperiodic response in mammals is mediated by nocturnal secretion of melatonin under the control of a circadian clock. However, artificial light at night caused by recent urbanization may disrupt the circadian clock, as well as the photoperiodic response by blunting melatonin secretion. Here we examined the effect of dim light at night (dLAN) (5lux of light during the dark phase) on locomotor activity rhythms and short-day regulation of reproduction, body mass, pelage properties, and immune responses of male Siberian hamsters. Short-day animals reduced gonadal and body mass, decreased spermatid nuclei and sperm numbers, molted to a whiter pelage, and increased pelage density compared to long-day animals. However, animals that experienced short days with dLAN did not show these short-day responses. Moreover, short-day specific immune responses were altered in dLAN conditions. The nocturnal activity pattern was blunted in dLAN hamsters, consistent with the observation that dLAN changed expression of the circadian clock gene, Period1. In addition, we demonstrated that expression levels of genes implicated in the photoperiodic response, Mel-1a melatonin receptor, Eyes absent 3, thyroid stimulating hormone receptor, gonadotropin-releasing hormone, and gonadotropin-inhibitory hormone, were higher in dLAN animals than those in short-day animals. These results suggest that dLAN disturbs the circadian clock function and affects the molecular mechanisms of the photoperiodic response. Copyright © 2013 Elsevier Inc. All rights reserved.

Engineering a Light-Attenuating Artificial Iris

Science.gov (United States)

Shareef, Farah J.; Sun, Shan; Kotecha, Mrignayani; Kassem, Iris; Azar, Dimitri; Cho, Michael

2016-01-01

Purpose Discomfort from light exposure leads to photophobia, glare, and poor vision in patients with congenital or trauma-induced iris damage. Commercial artificial iris lenses are static in nature to provide aesthetics without restoring the natural iris's dynamic response to light. A new photo-responsive artificial iris was therefore developed using a photochromic material with self-adaptive light transmission properties and encased in a transparent biocompatible polymer matrix. Methods The implantable artificial iris was designed and engineered using Photopia, a class of photo-responsive materials (termed naphthopyrans) embedded in polyethylene. Photopia was reshaped into annular disks that were spin-coated with polydimethylsiloxane (PDMS) to form our artificial iris lens of controlled thickness. Results Activated by UV and blue light in approximately 5 seconds with complete reversal in less than 1 minute, the artificial iris demonstrates graded attenuation of up to 40% of visible and 60% of UV light. There optical characteristics are suitable to reversibly regulate the incident light intensity. In vitro cell culture experiments showed up to 60% cell death within 10 days of exposure to Photopia, but no significant cell death observed when cultured with the artificial iris with protective encapsulation. Nuclear magnetic resonance spectroscopy confirmed these results as there was no apparent leakage of potentially toxic photochromic material from the ophthalmic device. Conclusions Our artificial iris lens mimics the functionality of the natural iris by attenuating light intensity entering the eye with its rapid reversible change in opacity and thus potentially providing an improved treatment option for patients with iris damage. PMID:27116547

Engineering a Light-Attenuating Artificial Iris.

Science.gov (United States)

Shareef, Farah J; Sun, Shan; Kotecha, Mrignayani; Kassem, Iris; Azar, Dimitri; Cho, Michael

2016-04-01

Discomfort from light exposure leads to photophobia, glare, and poor vision in patients with congenital or trauma-induced iris damage. Commercial artificial iris lenses are static in nature to provide aesthetics without restoring the natural iris's dynamic response to light. A new photo-responsive artificial iris was therefore developed using a photochromic material with self-adaptive light transmission properties and encased in a transparent biocompatible polymer matrix. The implantable artificial iris was designed and engineered using Photopia, a class of photo-responsive materials (termed naphthopyrans) embedded in polyethylene. Photopia was reshaped into annular disks that were spin-coated with polydimethylsiloxane (PDMS) to form our artificial iris lens of controlled thickness. Activated by UV and blue light in approximately 5 seconds with complete reversal in less than 1 minute, the artificial iris demonstrates graded attenuation of up to 40% of visible and 60% of UV light. There optical characteristics are suitable to reversibly regulate the incident light intensity. In vitro cell culture experiments showed up to 60% cell death within 10 days of exposure to Photopia, but no significant cell death observed when cultured with the artificial iris with protective encapsulation. Nuclear magnetic resonance spectroscopy confirmed these results as there was no apparent leakage of potentially toxic photochromic material from the ophthalmic device. Our artificial iris lens mimics the functionality of the natural iris by attenuating light intensity entering the eye with its rapid reversible change in opacity and thus potentially providing an improved treatment option for patients with iris damage.

Light pollution alters the phenology of dawn and dusk singing in common European songbirds.

Science.gov (United States)

Da Silva, Arnaud; Valcu, Mihai; Kempenaers, Bart

2015-05-05

Artificial night lighting is expanding globally, but its ecological consequences remain little understood. Animals often use changes in day length as a cue to time seasonal behaviour. Artificial night lighting may influence the perception of day length, and may thus affect both circadian and circannual rhythms. Over a 3.5 month period, from winter to breeding, we recorded daily singing activity of six common songbird species in 12 woodland sites, half of which were affected by street lighting. We previously reported on analyses suggesting that artificial night lighting affects the daily timing of singing in five species. The main aim of this study was to investigate whether the presence of artificial night lighting is also associated with the seasonal occurrence of dawn and dusk singing. We found that in four species dawn and dusk singing developed earlier in the year at sites exposed to light pollution. We also examined the effects of weather conditions and found that rain and low temperatures negatively affected the occurrence of dawn and dusk singing. Our results support the hypothesis that artificial night lighting alters natural seasonal rhythms, independently of other effects of urbanization. The fitness consequences of the observed changes in seasonal timing of behaviour remain unknown.

Bright-light exposure during daytime sleeping affects nocturnal melatonin secretion after simulated night work.

Science.gov (United States)

Nagashima, Shunsuke; Osawa, Madoka; Matsuyama, Hiroto; Ohoka, Wataru; Ahn, Aemi; Wakamura, Tomoko

2018-02-01

The guidelines for night and shift workers recommend that after night work, they should sleep in a dark environment during the daytime. However, staying in a dark environment during the daytime reduces nocturnal melatonin secretion and delays its onset. Daytime bright-light exposure after night work is important for melatonin synthesis the subsequent night and for maintaining the circadian rhythms. However, it is not clear whether daytime sleeping after night work should be in a dim- or a bright-light environment for maintaining melatonin secretion. The aim of this study, therefore, was to evaluate the effect of bright-light exposure during daytime sleeping on nocturnal melatonin secretion after simulated night work. Twelve healthy male subjects, aged 24.8 ± 4.6 (mean ± SD), participated in 3-day sessions under two experimental conditions, bright light or dim light, in a random order. On the first day, the subjects entered the experimental room at 16:00 and saliva samples were collected every hour between 18:00 and 00:00 under dim-light conditions. Between 00:00 and 08:00, they participated in tasks that simulated night work. At 10:00 the next morning, they slept for 6 hours under either a bright-light condition (>3000 lx) or a dim-light condition (night work were compared between the light conditions using paired t-tests. The ANOVA results indicated a significant interaction (light condition and3 day) (p = .006). Post hoc tests indicated that in the dim-light condition, the melatonin concentration was significantly lower on the second day than on the first day (p = .046); however, in the bright-light condition, there was no significant difference in the melatonin concentration between the days (p = .560). There was a significant difference in ΔDLMO between the conditions (p = .015): DLMO after sleeping was advanced by 11.1 ± 17.4 min under bright-light conditions but delayed for 7.2 ± 13.6 min after sleeping under dim-light conditions. No

Spotlight on fish: light pollution affects circadian rhythms of European perch but does not cause stress.

Science.gov (United States)

Brüning, Anika; Hölker, Franz; Franke, Steffen; Preuer, Torsten; Kloas, Werner

2015-04-01

Flora and fauna evolved under natural day and night cycles. However, natural light is now enhanced by artificial light at night, particularly in urban areas. This alteration of natural light environments during the night is hypothesised to alter biological rhythms in fish, by effecting night-time production of the hormone melatonin. Artificial light at night is also expected to increase the stress level of fish, resulting in higher cortisol production. In laboratory experiments, European perch (Perca fluviatilis) were exposed to four different light intensities during the night, 0 lx (control), 1 lx (potential light level in urban waters), 10 lx (typical street lighting at night) and 100 lx. Melatonin and cortisol concentrations were measured from water samples every 3h during a 24 hour period. This study revealed that the nocturnal increase in melatonin production was inhibited even at the lowest light level of 1 lx. However, cortisol levels did not differ between control and treatment illumination levels. We conclude that artificial light at night at very low intensities may disturb biological rhythms in fish since nocturnal light levels around 1 lx are already found in urban waters. However, enhanced stress induction could not be demonstrated. Copyright © 2014 Elsevier B.V. All rights reserved.

Pollination by nocturnal Lepidoptera, and the effects of light pollution: a review.

Science.gov (United States)

MacGregor, Callum J; Pocock, Michael J O; Fox, Richard; Evans, Darren M

2015-06-01

1. Moths (Lepidoptera) are the major nocturnal pollinators of flowers. However, their importance and contribution to the provision of pollination ecosystem services may have been under-appreciated. Evidence was identified that moths are important pollinators of a diverse range of plant species in diverse ecosystems across the world. 2. Moth populations are known to be undergoing significant declines in several European countries. Among the potential drivers of this decline is increasing light pollution. The known and possible effects of artificial night lighting upon moths were reviewed, and suggest how artificial night lighting might in turn affect the provision of pollination by moths. The need for studies of the effects of artificial night lighting upon whole communities of moths was highlighted. 3. An ecological network approach is one valuable method to consider the effects of artificial night lighting upon the provision of pollination by moths, as it provides useful insights into ecosystem functioning and stability, and may help elucidate the indirect effects of artificial light upon communities of moths and the plants they pollinate. 4. It was concluded that nocturnal pollination is an ecosystem process that may potentially be disrupted by increasing light pollution, although the nature of this disruption remains to be tested.

Light + architecture. Daylight - artificial light - energy; Licht + Architektur. Tageslicht - Kunstlicht - Energie

Energy Technology Data Exchange (ETDEWEB)

NONE

2009-07-01

The symposium intends to provide scientific and technical fundamentals for room lighting with daylight. Daylight deflection systems and artificial light control systems were analyzed for this purpose, and a catalogue of criteria was established. Planners were given tools for projecting daylight control systems. Builder-owners received the fundamentals for economic assessment of combined daylight and artificial light illumination systems, while industrial producers obtained information for further development to maturity and for marketing of daylight-dependent artificial light control systems. (GL)

Assessment of Interior and Area Artificial Lighting in Hospitals of Hamadan City

Directory of Open Access Journals (Sweden)

Rostam Golmohamadi

2014-04-01

Full Text Available Background & Objectives: Comfort lighting is one of the most important topics, which provides optimum physical conditions in general environment and workplaces such as hospitals. This study aimed to evaluate general, local and area artificial illumination of Hamadan city hospitals . Methods : In this descriptive-analytical study, general, local and area artificial illumination in seven Hamadan hospitals in 2006 were evaluated. Lighting intensities (illuminance were measured according to recommended IESNA method using the lux meter model (Lutron-Lx102 in the early hours of night. Lighting quality parameters such as color rendering, technical suitability of design and lighting uniformity were evaluated. Data was analyzed using SPSS 13 . Results : The average of interior illuminance was 90.44 ± 46.97 lx, which was lower than the national recommended limits. Maximum and minimum intensity values of interior illuminance were in nursing station and laboratory, respectively. The average of area illuminance was 47.92 ± 53.2 lx and local illuminance was 131.5 ± 60.2 lx, which were lower than the recommended limits. Maximum intensity of local illuminance was in laboratories and the minimum levels were in admitted rooms, checkup and injection units. In total, 90.6% of general interior lighting systems, 83.3% of area lighting systems and 100% of local lighting systems had unaccepted design . Conclusion : The average of general, local and area illuminance in Hamadan hospitals were not within the acceptable limits for comfort lighting. To obtain comfort lighting in studied hospitals, reforming and modifying lightening systems is necessary .

Light at night alters daily patterns of cortisol and clock proteins in female Siberian hamsters.

Science.gov (United States)

Bedrosian, T A; Galan, A; Vaughn, C A; Weil, Z M; Nelson, R J

2013-06-01

Humans and other organisms have adapted to a 24-h solar cycle in response to life on Earth. The rotation of the planet on its axis and its revolution around the sun cause predictable daily and seasonal patterns in day length. To successfully anticipate and adapt to these patterns in the environment, a variety of biological processes oscillate with a daily rhythm of approximately 24 h in length. These rhythms arise from hierarchally-coupled cellular clocks generated by positive and negative transcription factors of core circadian clock gene expression. From these endogenous cellular clocks, overt rhythms in activity and patterns in hormone secretion and other homeostatic processes emerge. These circadian rhythms in physiology and behaviour can be organised by a variety of cues, although they are most potently entrained by light. In recent history, there has been a major change from naturally-occurring light cycles set by the sun, to artificial and sometimes erratic light cycles determined by the use of electric lighting. Virtually every individual living in an industrialised country experiences light at night (LAN) but, despite its prevalence, the biological effects of such unnatural lighting have not been fully considered. Using female Siberian hamsters (Phodopus sungorus), we investigated the effects of chronic nightly exposure to dim light on daily rhythms in locomotor activity, serum cortisol concentrations and brain expression of circadian clock proteins (i.e. PER1, PER2, BMAL1). Although locomotor activity remained entrained to the light cycle, the diurnal fluctuation of cortisol concentrations was blunted and the expression patterns of clock proteins in the suprachiasmatic nucleus and hippocampus were altered. These results demonstrate that chronic exposure to dim LAN can dramatically affect fundamental cellular function and emergent physiology. © 2013 British Society for Neuroendocrinology.

RESEARCH OF NIGHT LIGHT EFFECTS ON COLORIMETRIC CHARACTERISTICS OF IMAGE PERCEIVED BY THE PILOT IN AN AIRCRAFT COCKPIT

Directory of Open Access Journals (Sweden)

I. O. Zharinov

2015-09-01

Full Text Available Subject of Research. The influence of radiation spectra from the source of artificial night light on colorimetric characteristics of image perceived by the pilot in the aircraft cockpit has been studied. The image is displayed on the LCD screen of multifunctional color indication equipment unit. Night illumination of the cockpit is performed with the use of artificial lamps of red, green, blue and, rarely, white light. Method. Any given color to be displayed on the screen is perceived by an observer differently with presence and absence of external illumination. When external light of white color is used, perceived color depends upon color temperature of the light source; if illumination source has any arbitrary spectral characteristics, then perceivable color depends upon whole spectral content of the used source. The color, perceived by an observer, is formed as the mixture of the color displayed on the screen (image element color with the color presented by diffuse reflection of external illumination source from the surface of the screen. The brightness of both colors is added. Mathematical expressions, that define calculation rule for chromaticity coordinates of color perceived by an observer, are based on the Grassmann’s law of additive color mixing. Quantitative analysis of the effect, caused by radiation spectra from an external source of artificial light on color gamut area, corresponding to image, perceived by an observer, has been performed through simulation in MathCad 15.0. Main Results. It was shown, that the color palette of on-board indication equipment, obtained on automated working place for any preset source of external illumination of fluorescent spectrum, corresponding to white light, is not usable correctly in the aircraft night flight mode. An observer loses ability to perceive properly saturated primary colors of red and blue in the case of green-blue light source of external illumination; and the same issue occurs with

From OLS to VIIRS, an overview of nighttime satellite aerosol retrievals using artificial light sources

Science.gov (United States)

Zhang, J.; Miller, S. D.; Reid, J. S.; Hyer, E. J.; McHardy, T. M.

2015-12-01

Compared to abundant daytime satellite-based observations of atmospheric aerosol, observations at night are relatively scarce. In particular, conventional satellite passive imaging radiometers, which offer expansive swaths of spatial coverage compared to non-scanning lidar systems, lack sensitivity to most aerosol types via the available thermal infrared bands available at night. In this talk, we make the fundamental case for the importance of nighttime aerosol information in forecast models, and the need to mitigate the existing nocturnal gap. We review early attempts at estimating nighttime aerosol optical properties using the modulation of stable artificial surface lights. Initial algorithm development using DMSP Operational Linescan System (OLS) has graduated to refined techniques based on the Suomi-NPP Visible Infrared Imaging Radiometer Suite (VIIRS) Day/Night Band (DNB). We present examples of these retrievals for selected cases and compare the results to available surface-based point-source validation data.

Determining Light Pollution of the Global Sky: GLOBE at Night

Science.gov (United States)

Henderson, S.; Meymaris, K.; Ward, D.; Walker, C.; Russell, R.; Pompea, S.; Salisbury, D.

2006-05-01

GLOBE at Night is an international science event designed to observe and record the visible stars as a means of measuring light pollution in a given location. Increased and robust understanding of our environment requires learning opportunities that take place outside of the conventional K-12 classroom and beyond the confines of the school day. This hands-on learning activity extended the traditional classroom and school day last March with a week of nighttime sky observations involving teachers, students and their families. The quality of the night sky for stellar observations is impacted by several factors including human activities. By observing cloud cover and locating specific constellations in the sky, students from around the world learned how the lights in their community contribute to light pollution, exploring the relationship between science, technology and their society. Students learned that light pollution impacts more than just the visibility of stars at night. Lights at night impact both the biology and ecology of many species in our environment. Students were able to participate in this global scientific campaign by submitting their observations through an online database, allowing for authentic worldwide research and analysis by participating scientists. Students and their families learned how latitude and longitude coordinates provide a location system to map and analyze the observation data submitted from around the globe. The collected data is available online for use by students, teachers and scientists worldwide to assess how the quality of the night sky varies around the world. This session will share how students and scientists across the globe can explore and analyze the results of this exciting campaign. GLOBE at Night is a collaborative effort sponsored by The GLOBE Program, the National Optical Astronomy Observatory (NOAO), Centro de Apoyo a la Didactica de la Astronomia (CADIAS), Windows to the Universe, and ESRI. The GLOBE Program is

Evaluating potential spectral impacts of various artificial lights on melatonin suppression, photosynthesis, and star visibility.

Directory of Open Access Journals (Sweden)

Martin Aubé

Full Text Available Artificial light at night can be harmful to the environment, and interferes with fauna and flora, star visibility, and human health. To estimate the relative impact of a lighting device, its radiant power, angular photometry and detailed spectral power distribution have to be considered. In this paper we focus on the spectral power distribution. While specific spectral characteristics can be considered harmful during the night, they can be considered advantageous during the day. As an example, while blue-rich Metal Halide lamps can be problematic for human health, star visibility and vegetation photosynthesis during the night, they can be highly appropriate during the day for plant growth and light therapy. In this paper we propose three new indices to characterize lamp spectra. These indices have been designed to allow a quick estimation of the potential impact of a lamp spectrum on melatonin suppression, photosynthesis, and star visibility. We used these new indices to compare various lighting technologies objectively. We also considered the transformation of such indices according to the propagation of light into the atmosphere as a function of distance to the observer. Among other results, we found that low pressure sodium, phosphor-converted amber light emitting diodes (LED and LED 2700 K lamps filtered with the new Ledtech's Equilib filter showed a lower or equivalent potential impact on melatonin suppression and star visibility in comparison to high pressure sodium lamps. Low pressure sodium, LED 5000 K-filtered and LED 2700 K-filtered lamps had a lower impact on photosynthesis than did high pressure sodium lamps. Finally, we propose these indices as new standards for the lighting industry to be used in characterizing their lighting technologies. We hope that their use will favor the design of new environmentally and health-friendly lighting technologies.

Acute effects of different light spectra on simulated night-shift work without circadian alignment.

Science.gov (United States)

Canazei, Markus; Pohl, Wilfried; Bliem, Harald R; Weiss, Elisabeth M

2017-01-01

Short-wavelength and short-wavelength-enhanced light have a strong impact on night-time working performance, subjective feelings of alertness and circadian physiology. In the present study, we investigated acute effects of white light sources with varied reduced portions of short wavelengths on cognitive and visual performance, mood and cardiac output.Thirty-one healthy subjects were investigated in a balanced cross-over design under three light spectra in a simulated night-shift paradigm without circadian adaptation.Exposure to the light spectrum with the largest attenuation of short wavelengths reduced heart rate and increased vagal cardiac parameters during the night compared to the other two light spectra without deleterious effects on sustained attention, working memory and subjective alertness. In addition, colour discrimination capability was significantly decreased under this light source.To our knowledge, the present study for the first time demonstrates that polychromatic white light with reduced short wavelengths, fulfilling current lighting standards for indoor illumination, may have a positive impact on cardiac physiology of night-shift workers without detrimental consequences for cognitive performance and alertness.

Two- and 4-hour bright-light exposures differentially effect sleepiness and performance the subsequent night.

Science.gov (United States)

Thessing, V C; Anch, A M; Muehlbach, M J; Schweitzer, P K; Walsh, J K

1994-03-01

The effect of two durations of bright light upon sleepiness and performance during typical night shift hours was assessed. Thirty normal, healthy young adults participated in a 2-night protocol. On the 1st night subjects were exposed to bright or dim light beginning at 2400 hours, under one of the following three conditions: bright light for 4 hours, dim light for 2 hours followed by bright light for 2 hours or dim light for 4 hours. Following light exposure, subjects remained awake until 0800 hours in a dimly lit room and slept in the laboratory between 0800 and 1600 hours, during which time sleep was estimated with actigraphy. Throughout the 2nd night, the multiple sleep latency test (MSLT), simulated assembly line task (SALT) performance, and subjective sleepiness were recorded. The single, 4-hour exposure to bright light was found to significantly increase MSLT scores and improve SALT performance during the early morning hours on the night following bright-light exposure. No significant effects were noted with a 2-hour exposure. The most likely explanation for these findings is a phase delay in the circadian rhythm of sleepiness-alertness.

The Effect of Creating an Artificial Night On Physiological Changes in Preterm Infants

Directory of Open Access Journals (Sweden)

Tayebeh Reyhani

2014-12-01

Full Text Available Introduction Preterm infants are exposed to irregular light for several weeks or months in the Neonatal intensive-care unit (NICU. This lack of maternal entrainment, the exposure to irregular extrauterine lighting and care in the nursery may contribute to the disturbances in body temperature, sleep and physiological changes that are commonly experienced by preterm infants. Materials and Methods This is a randomized clinical trial dual group study, 38 preterm infants (gestational age of 30-34 weeks due to prematurity hospitalized at NICU of Ghaem Hospital, Iran, were evaluated within 10 days. Infants were divided into two groups of 1200-1700 and 1701-2200g based on the weight and the weight of each group were randomized into artificial night (dark period was from 19 to 7 during incubator was covered with linen cloth & light period was from 7 to 19 removed the cover and control groups (continuous lighting. Mothers & infants through questionnaires, interviews, observation & document completion, changes in physiologic & weight before entering the study & then physiologic changes twice a day, weight & feeding tolerance were collected daily. Data were analyzed using SPSS version16 software. Results The two groups were matched in terms of other variables. Mean gestational age was (31.39+1.39 weeks in both groups, mean weight at study entry in period light of the (1415.8+ 263.46 and (1471.6 + 244.47 was in continuous lighting. The difference in oxygen saturation, respiratory rate, respectively, higher and lower in the intervention group than the control group. Result of the statistical analysis of repeated measures suggests that the difference between the two groups was significant (P

The International Globe at Night Citizen-Science Campaign: Shedding Light on Light Pollution

Science.gov (United States)

Walker, C. E.; Pompea, S. M.

2013-12-01

For 8 years now, the Globe at Night campaign has invited citizen-scientists worldwide to measure and record the brightness of their night sky by hunting for the faintest stars in a particular constellation. Students for science projects and scientists for research use the data to monitor levels of brightness or 'light pollution' around the world. They also use the Globe at Night data to understand light pollution's effects on energy consumption, plants, wildlife and human health, as well as our ability to enjoy a starry night sky. The dates of the campaign for 2014 have been extended to every month during the year. Ten days each month (when the Moon is not up between 8pm and 10pm) are the recommended times to take measurements for the campaign. However, one can participate at other times and dates, as long as the Moon is not in the night sky and it is more than an hour after sunset or more than an hour before sunrise. New in 2014 will be an Android app that will allow you to input visual measurements anytime the Moon is not up. Also possibly included will be an iPhone app that will take sky brightness measurements. The campaign dates and the 5 easy steps to participating in the campaign are listed at www.globeatnight.org. You do not need to register. Once on the report page, you enter your location, date and time (automatic for a smart device). You find the constellation of the month in the night sky. (Help is on the website.) Then you choose which chart looks most like what you see toward the constellation. Choose the icon for how clear or cloudy it is and hit the submit button and you are done! The fifth step is returning later to the website to compare your observations on the world map to others from around the globe. Included on the Globe at Night website are many helpful resources and tools from finding the constellations used in the campaign, to understanding concepts like light pollution, to games that test your expertise in choosing 'limiting magnitudes

Mice exposed to dim light at night exaggerate inflammatory responses to lipopolysaccharide.

Science.gov (United States)

Fonken, Laura K; Weil, Zachary M; Nelson, Randy J

2013-11-01

The mammalian circadian system regulates many physiological functions including inflammatory responses. Appropriately timed light information is essential for maintaining circadian organization. Over the past ∼120 years, urbanization and the widespread adoption of electric lights have dramatically altered lighting environments. Exposure to light at night (LAN) is pervasive in modern society and disrupts core circadian clock mechanisms. Because microglia are the resident macrophages in the brain and macrophages contain intrinsic circadian clocks, we hypothesized that chronic exposure to LAN would alter microglia cytokine expression and sickness behavior following LPS administration. Exposure to 4 weeks of dim LAN elevated inflammatory responses in mice. Mice exposed to dimly lit, as compared to dark, nights exaggerated changes in body temperature and elevated microglia pro-inflammatory cytokine expression following LPS administration. Furthermore, dLAN mice had a prolonged sickness response following the LPS challenge. Mice exposed to dark or dimly lit nights had comparable sickness behavior directly following the LPS injection; however, dLAN mice showed greater reductions in locomotor activity, increased anorectic behavior, and increased weight loss than mice maintained in dark nights 24h post-LPS injection. Overall, these data suggest that chronic exposure to even very low levels of light pollution may alter inflammatory responses. These results may have important implications for humans and other urban dwelling species that commonly experience nighttime light exposure. Copyright © 2013 Elsevier Inc. All rights reserved.

Shift work, light at night, and the risk of breast cancer.

Science.gov (United States)

Reed, Virginia A

2011-01-01

Studies of the effect of shift work have identified several negative health outcomes, most notably breast cancer. Disruption of circadian rhythm by exposure to light at night has been identified as the mechanism likely responsible for this outcome. This article recommends that health care institutions work with occupational health nurses to develop and implement hazard communication and policies concerning shift work, exposure to light at night, and increased risk for negative health outcomes, particularly breast cancer. 2011, SLACK Incorporated.

Global Trends in Exposure to Light Pollution in Natural Terrestrial Ecosystems

Directory of Open Access Journals (Sweden)

Jonathan Bennie

2015-03-01

Full Text Available The rapid growth in electric light usage across the globe has led to increasing presence of artificial light in natural and semi-natural ecosystems at night. This occurs both due to direct illumination and skyglow - scattered light in the atmosphere. There is increasing concern about the effects of artificial light on biological processes, biodiversity and the functioning of ecosystems. We combine intercalibrated Defense Meteorological Satellite Program’s Operational Linescan System (DMSP/OLS images of stable night-time lights for the period 1992 to 2012 with a remotely sensed landcover product (GLC2000 to assess recent changes in exposure to artificial light at night in 43 global ecosystem types. We find that Mediterranean-climate ecosystems have experienced the greatest increases in exposure, followed by temperate ecosystems. Boreal, Arctic and montane systems experienced the lowest increases. In tropical and subtropical regions, the greatest increases are in mangroves and subtropical needleleaf and mixed forests, and in arid regions increases are mainly in forest and agricultural areas. The global ecosystems experiencing the greatest increase in exposure to artificial light are already localized and fragmented, and often of particular conservation importance due to high levels of diversity, endemism and rarity. Night time remote sensing can play a key role in identifying the extent to which natural ecosystems are exposed to light pollution.

"Chrono-functional milk": The difference between melatonin concentrations in night-milk versus day-milk under different night illumination conditions.

Science.gov (United States)

Asher, A; Shabtay, A; Brosh, A; Eitam, H; Agmon, R; Cohen-Zinder, M; Zubidat, A E; Haim, A

2015-01-01

Pineal melatonin (MLT) is produced at highest levels during the night, under dark conditions. We evaluated differences in MLT-concentration by comparing daytime versus night time milk samples, from two dairy farms with different night illumination conditions: (1) natural dark (Dark-Night); (2) short wavelength Artificial Light at Night (ALAN, Night-Illuminated). Samples were collected from 14 Israeli Holstein cows from each commercial dairy farm at 04:30 h ("Night-milk") 12:30 h ("Day-milk") and analyzed for MLT-concentration. In order to study the effects of night illumination conditions on cows circadian rhythms, Heart Rate (HR) daily rhythms were recorded. MLT-concentrations of Night-milk samples from the dark-night group were significantly (p Night-illuminated conditions (30.70 ± 1.79 and 17.81 ± 0.33 pg/ml, respectively). Interestingly, night illumination conditions also affected melatonin concentrations at daytime where under Dark-Night conditions values are significantly (p Night-Illuminated conditions, (5.36 ± 0.33 and 3.30 ± 0.18 pg/ml, respectively). There were no significant differences between the two treatments in the milk yield and milk composition except somatic cell count (SCC), which was significantly lower (p = 0.02) in the Dark-Night group compared with the Night-Illuminated group. Cows in both groups presented a significant (p night illuminated cows feeding and milking time are the "time keeper", while in the Dark-night cows, HR rhythms were entrained by the light/dark cycle. The higher MLT-concentration in Dark-night cows with the lower SCC values calls upon farmers to avoid exposure of cows to ALAN. Therefore, under Dark-night conditions milk quality will improve by lowering SCC values where separation between night and day of such milk can produce chrono-functional milk, naturally rich with MLT.

Session 21.2 - Measurement of Light at Night

Science.gov (United States)

Wainscoat, Richard J.

2016-10-01

The introduction of the mercury vapor lamp for general lighting in the 1930s probably marked the beginning of significant light pollution. Lighting levels have increased slowly, year-to-year, with sky brightness levels increasing only slowly on timescales of a year; no measurement protocols or instruments existed to quantify this increase. However, on timescales of 10-20 years, or on generational timescales, the increases in night sky levels, particularly in urban areas, have been dramatic. Younger people speak with their parents or grandparents who remark how beautiful the sky used to be, and how many stars they could see when they when they were younger. Older people can themselves remember how many stars were visible in the sky when they were younger. Whole generations of children now grow up without ever seeing the Milky Way. Society has not had tools to easily measure sky brightness, and monitoring from space has only recently become available. A subtle increase of 10% sky brightness per year, for example, is not noticeable to the human eye on the time scale of a year, and has been tolerated by society. But such an increase compounds to an increase of a factor 2.6 in 10 years, 6.7 in 20 years, and a factor 45 in 40 years, corresponding to a dramatic increase in sky brightness, an almost complete loss in ability to see faint objects in the night sky, and rendering the sky unusable for most forms of astronomy. The most striking examples are the urban observatories found in many major cities that can no longer be used. Session 2 was primarily focused on measurement of light at night, with an emphasis on measurement of light pollution. It comprised of 6 papers that are summarized below. Over the last decade, our ability to measure light pollution has grown tremendously, and the instrumentation needed to produce reliable quantitative measurements has become much more affordable, and now includes consumer grade digital cameras and even smart phones. During this same

Night-sky brightness monitoring in Hong Kong: a city-wide light pollution assessment.

Science.gov (United States)

Pun, Chun Shing Jason; So, Chu Wing

2012-04-01

Results of the first comprehensive light pollution survey in Hong Kong are presented. The night-sky brightness was measured and monitored around the city using a portable light-sensing device called the Sky Quality Meter over a 15-month period beginning in March 2008. A total of 1,957 data sets were taken at 199 distinct locations, including urban and rural sites covering all 18 Administrative Districts of Hong Kong. The survey shows that the environmental light pollution problem in Hong Kong is severe-the urban night skies (sky brightness at 15.0 mag arcsec(- 2)) are on average ~ 100 times brighter than at the darkest rural sites (20.1 mag arcsec(- 2)), indicating that the high lighting densities in the densely populated residential and commercial areas lead to light pollution. In the worst polluted urban location studied, the night-sky at 13.2 mag arcsec(- 2) can be over 500 times brighter than the darkest sites in Hong Kong. The observed night-sky brightness is found to be affected by human factors such as land utilization and population density of the observation sites, together with meteorological and/or environmental factors. Moreover, earlier night skies (at 9:30 p.m. local time) are generally brighter than later time (at 11:30 p.m.), which can be attributed to some public and commercial lightings being turned off later at night. On the other hand, no concrete relationship between the observed sky brightness and air pollutant concentrations could be established with the limited survey sampling. Results from this survey will serve as an important database for the public to assess whether new rules and regulations are necessary to control the use of outdoor lightings in Hong Kong.

Night work, light exposure and melatonin on work days and days off

DEFF Research Database (Denmark)

Daugaard, Stine; Garde, Anne Helene; Bonde, Jens Peter Ellekilde

2017-01-01

We aimed to examine the effects of night work on salivary melatonin concentration during and subsequent to night work and the mediating role of light. We included 254 day workers and 87 night workers who were followed during 322 work days and 301 days off work. Each day was defined as the 24 hour...... period starting from the beginning of a night shift or from waking in the mornings with day work and days off. Light levels were recorded and synchronized with diary information (start and end of sleep and work). On average, participants provided four saliva samples per day, and these were analyzed...... for melatonin concentration by liquid chromatography tandem mass spectrometry (LC-MS/MS). Differences between day and night workers on work days and days off were assessed with multilevel regression models with melatonin concentration as the primary outcome. All models were stratified or adjusted by time of day...

The health risks associated with energy efficient fluorescent, LEDs, and artificial lighting

Science.gov (United States)

Panahi, Allen

2014-09-01

With the phasing out of incandescent lamps in many countries, the introduction of new LED based light sources and luminaries sometimes raise the question of whether the spectral characteristics of the LED and other energy savings Fluorescent lights including the popular CFLs are suitable to replace the traditional incandescent lamps. These concerns are sometimes raised particularly for radiation emissions in the UV and Blue parts of the spectrum. This paper aims to address such concerns for the common `white light' sources typically used in household and other general lighting used in the work place. Recent studies have shown that women working the night shift have an increased probability of developing breast cancer. We like to report on the findings of many studies done by medical professionals, in particular the recent announcement of AMA in the US and many studies conducted in the UK, as well as the European community to increase public awareness on the long term health risks of the optical and opto-biological effects on the human health caused by artificial lighting.

GLOBE at Night: a Worldwide Citizen-Science Program to Increase Awareness of Light Pollution by Measuring Night Sky Brightness

Science.gov (United States)

Walker, C. E.; Pompea, S. M.

2011-12-01

The emphasis in the international citizen-science, star-hunting campaign, GLOBE at Night, is in bringing awareness to the public on issues of light pollution. Light pollution threatens not only observatory sites and our "right to starlight", but can affect energy consumption, wildlife and health. GLOBE at Night has successfully reached a few 100,000 citizen-scientists. What has contributed to its success? Foundational resources are available to facilitate the public's participation in promoting dark skies awareness. The GLOBE at Night website explains clearly the simple-to-participate-in 5 step program and offers background information and interactive games on key concepts. To promote the campaign via popular social media, GLOBE at Night created Facebook and Twitter pages. The program has been expanded to include trainings of the general public, but especially educators in schools, museums and science centers, in unique ways. Education kits for dark skies awareness have been distributed at the training workshops. The kit includes material for a light shielding demonstration, a digital Sky Quality Meter and "Dark Skies Rangers" activities. The activities are on how unshielded light wastes energy, how light pollution affects wildlife and how one can participate in a citizen-science star-hunt like GLOBE at Night. To increase participation in the 2011 campaign, children and adults submitted their sky brightness measurements in real time with smart phones or tablets using the web application at www.globeatnight.org/webapp/. With smart phones and tablets, the location, date and time register automatically. For those without smart mobile devices, user-friendly tools on the GLOBE at Night report page were reconfigured to determine latitude and longitude more easily and accurately. As a proto-type for taking multiple measurements, people in Tucson found it easy to adopt a street and take measurements every mile for the length of the street. The grid of measurements

Light and architecture. Daylight - artificial light - energy; Licht und Architektur. Tageslicht - Kunstlicht - Energie

Energy Technology Data Exchange (ETDEWEB)

Wambsganss, M. (ed.) [ip5 ingenieurpartnerschaft, Karlsruhe (Germany)]|[Fachhochschule Rosenheim (Germany)

2007-07-01

The symposium intends to provide scientific and technical fundamentals for room lighting with daylight. Daylight deflection systems and artificial light control systems were analyzed for this purpose, and a catalogue of criteria was established. Planners were given tools for projecting daylight control systems. Builder-owners received the fundamentals for economic assessment of combined daylight and artificial light illumination systems, while industrial producers obtained information for further development to maturity and for marketing of daylight-dependent artificial light control systems. (GL)

Results from the Prototype GLOBE at Night Worldwide Light Pollution Observation Program

Science.gov (United States)

Walker, Constance E.; Pompea, S. M.; Isbell, D.; Orellana, D.; Blurton, C.; Henderson, S.

2006-06-01

Students, families, and educators worldwide participated in GLOBE at Night - an international event designed to observe and record the visible stars as a means of measuring light pollution in a given location. Participation was open to anyone - anywhere in the world - who could get outside and look skyward during the week of March 22-29, 2006. Our goal was 5000 observations from around the world in this prototype program.The hands-on learning activities associated with the program were designed to extend the traditional classroom and school day with a week of nighttime observations involving teachers, students and their families. By locating specific constellations in the sky, students from around the world learned how the lights in their community contribute to light pollution. Students explored the different light sources in their community learning the relationship between science, technology and society, and they reported their observations online through a central database allowing for authentic worldwide research and analysis. The observations made during GLOBE at Night helped students and scientists together assess how the quality of the night sky varies around the world as well as the level of energy wastage associated with poorly-shielded lights.For more information, visit http://www.globe.gov/globeatnight.GLOBE at Night is a collaboration between The GLOBE Program, the National Optical Astronomy Observatory (NOAO), Centro de Apoyo a la Didactica de la Astronomia (CADIAS) in Chile , Windows to the Universe, and Environmental Systems Research Institute, Inc. (ESRI).

Coastal urban lighting has ecological consequences for multiple trophic levels under the sea.

Science.gov (United States)

Bolton, D; Mayer-Pinto, M; Clark, G F; Dafforn, K A; Brassil, W A; Becker, A; Johnston, E L

2017-01-15

Urban land and seascapes are increasingly exposed to artificial lighting at night (ALAN), which is a significant source of light pollution. A broad range of ecological effects are associated with ALAN, but the changes to ecological processes remain largely unstudied. Predation is a key ecological process that structures assemblages and responds to natural cycles of light and dark. We investigated the effect of ALAN on fish predatory behaviour, and sessile invertebrate prey assemblages. Over 21days fish and sessile assemblages were exposed to 3 light treatments (Day, Night and ALAN). An array of LED spotlights was installed under a wharf to create the ALAN treatments. We used GoPro cameras to film during the day and ALAN treatments, and a Dual frequency IDentification SONar (DIDSON) to film during the night treatments. Fish were most abundant during unlit nights, but were also relatively sedentary. Predatory behaviour was greatest during the day and under ALAN than at night, suggesting that fish are using structures for non-feeding purposes (e.g. shelter) at night, but artificial light dramatically increases their predatory behaviour. Altered predator behaviour corresponded with structural changes to sessile prey assemblages among the experimental lighting treatments. We demonstrate the direct effects of artificial lighting on fish behaviour and the concomitant indirect effects on sessile assemblage structure. Current and future projected use of artificial lights has the potential to significantly affect predator-prey interactions in marine systems by altering habitat use for both predators and prey. However, developments in lighting technology are a promising avenue for mitigation. This is among the first empirical evidence from the marine system on how ALAN can directly alter predation, a fundamental ecosystem process, and have indirect trophic consequences. Copyright © 2016 Elsevier B.V. All rights reserved.

Method to improve the survival of night-swarming mayflies near bridges in areas of distracting light pollution.

Science.gov (United States)

Egri, Ádám; Száz, Dénes; Farkas, Alexandra; Pereszlényi, Ádám; Horváth, Gábor; Kriska, György

2017-11-01

Numerous negative ecological effects of urban lighting have been identified during the last decades. In spite of the development of lighting technologies, the detrimental effect of this form of light pollution has not declined. Several insect species are affected including the night-swarming mayfly Ephoron virgo : when encountering bridges during their mass swarming, these mayflies often fall victim to artificial lighting. We show a simple method for the conservation of these mayflies exploiting their positive phototaxis. With downstream-facing light-emitting diode beacon lights above two tributaries of the river Danube, we managed to guide egg-laying females to the water and prevent them from perishing outside the river near urban lights. By means of measuring the mayfly outflow from the river as a function of time and the on/off state of the beacons, we showed that the number of mayflies exiting the river's area was practically zero when our beacons were operating. Tributaries could be the sources of mayfly recolonization in case of water quality degradation of large rivers. The protection of mayfly populations in small rivers and safeguarding their aggregation and oviposition sites is therefore important.

Scheduled Evening Sleep and Enhanced Lighting Improve Adaptation to Night Shift Work in Older Adults

Science.gov (United States)

Chinoy, Evan D.; Harris, Michael P.; Kim, Min Ju; Wang, Wei; Duffy, Jeanne F.

2017-01-01

Objectives We tested whether a sleep and circadian-based treatment shown to improve circadian adaptation to night shifts and attenuate negative effects on alertness, performance, and sleep in young adults would also be effective in older adults. Methods We assessed subjective alertness, sustained attention (psychomotor vigilance task, PVT), sleep duration (actigraphy), and circadian timing (salivary dim-light melatonin onset, DLMO) in eighteen older adults (57.2±3.8 y; mean±SD) in a simulated shift work protocol. Four day shifts were followed by three night shifts in the laboratory. Participants slept at home and were randomized to either the Treatment Group (scheduled evening sleep and enhanced lighting during the latter half of night shifts), or Control Group (ad lib sleep and typical lighting during night shifts). Results Compared to day shifts, alertness and sustained attention declined on the first night shift in both groups, and was worse in the latter half of the night shifts. Alertness and attention improved on nights 2 and 3 for the Treatment Group but remained lower for the Control Group. Sleep duration in the Treatment Group remained similar to baseline (6–7 h) following night shifts, but was shorter (3–5 h) following night shifts in the Control Group. Treatment Group circadian timing advanced by 169.3±16.1 min (mean±SEM) but did not shift (−9.7±9.9 min) in the Control Group. Conclusions The combined treatment of scheduled evening sleep and enhanced lighting increased sleep duration and partially aligned circadian phase with sleep and work timing, resulting in improved night shift alertness and performance. PMID:27566781

Time-dependent effects of dim light at night on re-entrainment and masking of hamster activity rhythms.

Science.gov (United States)

Frank, David W; Evans, Jennifer A; Gorman, Michael R

2010-04-01

Bright light has been established as the most ubiquitous environmental cue that entrains circadian timing systems under natural conditions. Light equivalent in intensity to moonlight (dim nighttime illumination accelerated re-entrainment of hamster activity rhythms to 4-hour phase advances and delays of an otherwise standard laboratory photocycle. The purpose of this study was to determine if a sensitive period existed in the night during which dim illumination had a robust influence on speed of re-entrainment. Male Siberian hamsters were either exposed to dim light throughout the night, for half of the night, or not at all. Compared to dark nights, dim illumination throughout the entire night decreased by 29% the time for the midpoint of the active phase to re-entrain to a 4-hour phase advance and by 26% for a 4-hour delay. Acceleration of advances and delays were also achieved with 5 hours of dim light per night, but effects depended on whether dim light was present in the first half, second half, or first and last quarters of the night. Both during phase shifting and steady-state entrainment, partially lit nights also produced strong positive and negative masking effects, as well as entrainment aftereffects in constant darkness. Thus, even in the presence of a strong zeitgeber, light that might be encountered under a natural nighttime sky potently modulates the circadian timing system of hamsters.

Combined effects of night warming and light pollution on predator-prey interactions.

Science.gov (United States)

Miller, Colleen R; Barton, Brandon T; Zhu, Likai; Radeloff, Volker C; Oliver, Kerry M; Harmon, Jason P; Ives, Anthony R

2017-10-11

Interactions between multiple anthropogenic environmental changes can drive non-additive effects in ecological systems, and the non-additive effects can in turn be amplified or dampened by spatial covariation among environmental changes. We investigated the combined effects of night-time warming and light pollution on pea aphids and two predatory ladybeetle species. As expected, neither night-time warming nor light pollution changed the suppression of aphids by the ladybeetle species that forages effectively in darkness. However, for the more-visual predator, warming and light had non-additive effects in which together they caused much lower aphid abundances. These results are particularly relevant for agriculture near urban areas that experience both light pollution and warming from urban heat islands. Because warming and light pollution can have non-additive effects, predicting their possible combined consequences over broad spatial scales requires knowing how they co-occur. We found that night-time temperature change since 1949 covaried positively with light pollution, which has the potential to increase their non-additive effects on pea aphid control by 70% in US alfalfa. Our results highlight the importance of non-additive effects of multiple environmental factors on species and food webs, especially when these factors co-occur. © 2017 The Author(s).

Scheduled evening sleep and enhanced lighting improve adaptation to night shift work in older adults.

Science.gov (United States)

Chinoy, Evan D; Harris, Michael P; Kim, Min Ju; Wang, Wei; Duffy, Jeanne F

2016-12-01

We tested whether a sleep and circadian-based treatment shown to improve circadian adaptation to night shifts and attenuate negative effects on alertness, performance and sleep in young adults would also be effective in older adults. We assessed subjective alertness, sustained attention (psychomotor vigilance task, PVT), sleep duration (actigraphy) and circadian timing (salivary dim-light melatonin onset, DLMO) in 18 older adults (57.2±3.8 years; mean±SD) in a simulated shift work protocol. 4 day shifts were followed by 3 night shifts in the laboratory. Participants slept at home and were randomised to either the treatment group (scheduled evening sleep and enhanced lighting during the latter half of night shifts) or control group (ad-lib sleep and typical lighting during night shifts). Compared with day shifts, alertness and sustained attention declined on the first night shift in both groups, and was worse in the latter half of the night shifts. Alertness and attention improved on nights 2 and 3 for the treatment group but remained lower for the control group. Sleep duration in the treatment group remained similar to baseline (6-7 hours) following night shifts, but was shorter (3-5 hours) following night shifts in the control group. Treatment group circadian timing advanced by 169.3±16.1 min (mean±SEM) but did not shift (-9.7±9.9 min) in the control group. The combined treatment of scheduled evening sleep and enhanced lighting increased sleep duration and partially aligned circadian phase with sleep and work timing, resulting in improved night shift alertness and performance. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/.

Artificial light and quantum order in systems of screened dipoles

International Nuclear Information System (INIS)

Wen Xiaogang

2003-01-01

The origin of light is an unsolved mystery in nature. Recently, it was suggested that light may originate from a new kind of order, quantum order. To test this idea in experiments, we study systems of screened magnetic/electric dipoles in two-dimensional (2D) and 3D lattices. We show that our models contain an artificial light-a photonlike collective excitation. We discuss how to design realistic devices that realize our models. We show that the 'speed of light' and the 'fine-structure constant' of the artificial light can be tuned in our models. The properties of artificial atoms (bound states of pairs of artificial charges) are also discussed. The existence of artificial light (as well as artificial electron) in condensed-matter systems suggests that elementary particles, such as light and electron, may not be elementary. They may be collective excitations of quantum order in our vacuum. In our model, light is realized as a fluctuation of string-nets and charges as the ends of open strings (or nodes of string nets)

Light Pollution and Wildlife

Science.gov (United States)

Duffek, J.

2008-12-01

for Educational Program IYA Dark Skies Education Session Fall American Geophysical Union San Francisco, December 15-19, 2008 Light Pollution and Wildlife This is a very exciting time to be a part of the mission to keep the nighttime skies natural. The International Year of Astronomy (IYA) 2009 is developing programs for all areas of Dark Skies Awareness. For many years the issue of light pollution focused on the impact to the astronomy industry. While this is an important area, research has shown that light pollution negatively impacts wildlife, their habitat, human health, and is a significant waste of energy. Since the message and impact of the effects of light pollution are much broader now, the message conveyed to the public must also be broader. Education programs directed at youth are a new frontier to reach out to a new audience about the adverse effects of too much artificial light at night. The International Dark-Sky Association (IDA) has developed educational presentations using the National Science Teachers Association Education Standards. These programs focus on youth between the ages of 5 to 17exploring new territory in the education of light pollution. The IDA education programs are broken down into three age groups; ages 5-9, 8-13, 12 and older. The presentations come complete with PowerPoint slides, discussion notes for each slide, and workbooks including age appropriate games to keep young audiences involved. A new presentation reflects the growing area of interest regarding the effects of too much artificial light at night on wildlife. This presentation outlines the known problems for ecosystems caused by artificial light at night. Insects are attracted to artificial lights and may stay near that light all night. This attraction interferes with their ability to migrate, mate, and look for food. Such behavior leads to smaller insect populations. Fewer insects in turn affect birds and bats, because they rely on insects as a food source. The IDA

Does Current Scientific Evidence Support a Link Between Light at Night and Breast Cancer Among Female Night-Shift Nurses?

Science.gov (United States)

Dickerman, Barbra; Liu, Jianghong

2014-01-01

Breast cancer is increasingly prevalent in industrialized regions of the world, and exposure to light at night (LAN) has been proposed as a potential risk factor. Epidemiological observations have documented an increased breast cancer risk among female night-shift workers, and strong experimental evidence for this relationship has also been found in rodent models. Indirect support for the LAN hypothesis comes from studies involving blind women, sleep duration, bedroom light levels, and community nighttime light levels. This article reviews the literature, discusses possible mechanisms of action, and provides recommendations for occupational health nursing research, practice, and education. Research is needed to further explore the relationship between exposure to LAN and breast cancer risk and elucidate the mechanisms underlying this relationship before interventions can be designed for prevention and mitigation of breast cancer. PMID:22658734

Circadian adaptation to night-shift work by judicious light and darkness exposure.

Science.gov (United States)

Boivin, Diane B; James, Francine O

2002-12-01

In this combined field and laboratory investigation, the authors tested the efficacy of an intervention designed to promote circadian adaptation to night-shift work. Fifteen nurses working permanent night schedules (> or = 8 shifts/ 15 days) were recruited from area hospitals. Following avacation period of > or = 10 days on a regular daytime schedule, workers were admitted to the laboratory for the assessment of circadian phase via a 36-h constant routine. They returned to work approximately 12 night shifts on their regular schedules under one of two conditions. Treatment group workers (n = 10, mean age +/- SD = 41.7 +/- 8.8 years) received an intervention including 6 h of intermittent bright-light exposure in the workplace (approximately 3,243 lux) and shielding from bright morning outdoor light with tinted goggles (15% visual light transmission). Control group workers (n = 9, mean age +/- SD = 42.0 +/- 7.2 years) were observed in their habitual work environments. On work days, participants maintained regular sleep/wake schedules including a single 8-h sleep/darkness episode beginning 2 h after the end of the night shift. A second 36-h constant routine was performed following the series of night shifts. In the presence of the intervention, circadian rhythms of core body temperature and salivary melatonin cycles were delayed by an average (+/- SEM) of -9.32 +/- 1.06 h and -11.31 +/- 1.13 h, respectively. These were significantly greater than the phase delays of -4.09 +/- 1.94 h and -5.08 +/- 2.32 h displayed by the control group (p = 0.03 and p = 0.02, respectively). The phase angle between circadian markers and the shifted schedule was reestablished to its baseline position only in the treatment group of workers. These results support the efficacy of a practical intervention for promoting circadian adaptation to night-shift work under field conditions. They also underline the importance of controlling the overall pattern of exposure to light and darkness in

Detailed simulations of lighting conditions in office rooms lit by daylight and artificial light

DEFF Research Database (Denmark)

Iversen, Anne

In this thesis the effect on the annual artificial lighting demand is investigated by employing detailed simulations of lighting conditions in office rooms lit by daylight and artificial. The simulations of the artificial lighting demand is accomplished through daylight simulations in Radiance....... The detailed simulations includes studies of the resolution of different weather data sets in climate-based daylight modeling. Furthermore, influence of the electrical lighting demand by simulating with dynamic occupancy patterns is studied. Finally the thesis explores the influence of obstructions in an urban...... canyon on the daylight availability within the buildings, and hence on the energy consumption for artificial lights. The results from the thesis demonstrates that the effect on the outcome of the daylight simulations when simulating with typical weather data files for the location of Copenhagen...

Light at night pollution of the internal clock, a public health issue.

Science.gov (United States)

Touitou, Yvan

2015-10-01

Light is the major synchronizer of the internal clock located in the suprachiasmatic nuclei of the anterior hypothalamus. Retinal ganglion cells contain melanopsin, a photoreceptor with a peak sensitivity to blue wavelength (460-480 nm). Light signal is transmitted from the eye to the clock, then to the pineal gland which produces melatonin, considered as the hand of the clock. Even a weak intensity of light (LEDs, tablets, mobile phones, computers...) is able to block the secretion of melatonin, the hormone of darkness. Light is also able to phase advance or phase delay the circadian system according to the timing of exposure. This Phase Response Curve (PRC) is used to resynchronize the clock in various situations of circadian desynchronization. Exposure to Light at Night (LAN) results in a disruption of the circadian system which is deleterious to health. In industrialized countries, including France, 75 % of the total workforce is estimated to be involved in atypical hours, far from the classical diurnal hours of work. Of interest, shift work and night work involve 15.4 % of the French workforce. A number of epidemiologic studies, peiformed mainly on nurses, showed an association between sustained night work (3 to 20 years) and an increased risk of breast cancer Health problems faced by flight attendants have also been reported, though other causes like exposure to radiations cannot be ruled out. Other deleterious effects are reported in this paper. The potential mechanisms of the deleterious effects of LAN on health are suppression of melatonin andsleep deprivation. The International Agencyfor Cancer Research (IARC) classified shift work that involves circadian disruption as ( probably carcinogenic to humans". Countermeasures (e.g melatonin, bright light, use of psychotropic drugs) have been proposed as a means to improve adaptation to shift work and night work and to fight " clock pollution " and circadian desynchronization by LAN.

USE OF ARTIFICIAL LIGHT IN MUSHROOM CULTIVATION

Directory of Open Access Journals (Sweden)

N. L. Poyedinok

2013-12-01

Full Text Available Artificial light is used in greenhouses to increase productivity and quality of agricultural and ornamental plants. Despite the awareness of the fact that light also plays important role in the life of nonhotosynthetic organisms, such as fungi, its using in their biotechnology cultivation is currently limited. Science has quite a large amount information about the influence of artificial light of different nature on morphogenesis, metabolic processes and productivity of more than 100 species of fungi, many of which are valuable producers of biologically active compounds. Themechanisms of photoreactions of various fungi, which is an integral part of a purposeful photoregulation their activity in biotechnological processes are described. The analysis of the researches and of the experience of their practical application allows predicting potential of using artificial light in mushroom growing industry, as well as in creating highly productive, environmentally clean technologies of targeted synthesis of the final product.

Restless roosts : Light pollution affects behavior, sleep, and physiology in a free-living songbird

NARCIS (Netherlands)

Ouyang, Jenny Q; de Jong, Maaike; van Grunsven, Roy H A; Matson, Kevin D; Haussmann, Mark F; Meerlo, Peter; Visser, Marcel E; Spoelstra, Kamiel

The natural nighttime environment is increasingly polluted by artificial light. Several studies have linked artificial light at night to negative impacts on human health. In free-living animals, light pollution is associated with changes in circadian, reproductive, and social behavior, but whether

Restless roosts: Light pollution affects behavior, sleep, and physiology in a free-living songbird

NARCIS (Netherlands)

Ouyang, Jenny Q.; de Jong, Maaike; van Grunsven, Roy H. A.; Matson, Kevin D.; Haussmann, Mark F.; Meerlo, Peter; Visser, Marcel E.; Spoelstra, Kamiel

2017-01-01

The natural nighttime environment is increasingly polluted by artificial light. Several studies have linked artificial light at night to negative impacts on human health. In free-living animals, light pollution is associated with changes in circadian, reproductive, and social behavior, but whether

Restless roosts : Light pollution affects behavior, sleep, and physiology in a free-living songbird

NARCIS (Netherlands)

Ouyang, Jenny Q; de Jong, Maaike; van Grunsven, Roy H A; Matson, Kevin D; Haussmann, Mark F; Meerlo, Peter; Visser, Marcel E; Spoelstra, Kamiel

2017-01-01

The natural nighttime environment is increasingly polluted by artificial light. Several studies have linked artificial light at night to negative impacts on human health. In free-living animals, light pollution is associated with changes in circadian, reproductive, and social behavior, but whether

Evaluation of blue light exposure to beta brainwaves on simulated night driving

Science.gov (United States)

Purawijaya, Dandri Aly; Fitri, Lulu Lusianti; Suprijanto

2015-09-01

Numbers of night driving accident in Indonesia since 2010 are exponentially rising each year with total of loss more than 50 billion rupiah. One of the causes that contribute to night driving accident is drowsiness. Drowsiness is affected by circadian rhythm resulted from the difference of blue light quality and quantity between night and day. Blue light may effect on human physiology through non-visual pathway by suppressing melatonin hormone suppression that influence drowsiness. Meanwhile, the production of hormones and other activities in brain generate bioelectrical activity such as brainwaves and can be recorded using Electroencephalograph (EEG). Therefore, this research objective is to evaluate the effect of blue light exposure to beta brainwave emergence during night driving simulation to a driver. This research was conducted to 4 male subjects who are able to drive and have a legitimate car driving license. The driving simulator was done using SCANIA Truck Driving Simulator on freeform driving mode in dark environment. Subjects drove for total 32 minutes. The data collections were taken in 2 days with 16 minutes for each day. The 16 minutes were divided again into 8 minutes adaptation in dark and 8 minutes for driving either in blue light exposure or in total darkness. While driving the simulation, subjects' brainwaves were recorded using EEG EMOTIV 14 Channels, exposed by LED monochromatic blue light with 160 Lux from source and angle 45o and sat 1 m in front of the screen. Channels used on this research were for visual (O1; O2), cognition (F3; F4; P7; P8), and motor (FC5; FC6). EEG brainwave result was filtered with EEGLab to obtain beta waves at 13 - 30 Hz frequencies. Results showed that beta waves response to blue light varied for each subject. Blue light exposure either increased or decreased beta waves in 2 minutes pattern and maintaining beta waves on cognition and motor area in 3 out of 4 subjects. Meanwhile, blue light exposure did not maintain

Influence of artificial lights on the orientation of hatchlings of Eretmochelys imbricata in Pernambuco, Brazil

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Thyara Noely Simões

2017-10-01

Full Text Available ABSTRACT Sea turtle hatchlings, in natural abiotic conditions, emerge from their nests at night and go directly to the sea, following the moonlight’s reflection in the ocean. Increased human activities such as tourism and artificial lights on the coasts, however, have interfered with the ability of sea turtle neonates to find their correct destination, negatively affecting their survival rates. Here we endeavored to assess the influence of artificial lights on the hatchlings of the sea turtle Eretmochelys imbricata (Linnaeus, 1766 in the south coast of the state of Pernambuco, Brazil. To that end, 10 experiments were conducted with 15 hatchlings/test subjects. Five experiments took place in artificially illuminated areas and five in non-illuminated areas. Circles with a 2 m radius were drawn on the sand a small 2-3 cm depression was made at the center of each circles. The neonates were then placed in the depressions to simulate their coming from a nest. After the neonates crossed the edge of the circles, their tracks were photographed and drawn on a diagram. To ascertain if the trajectories of the neonates differed between the two groups (hatchlings from illuminated versus non-illuminated nests, the Rayleigh test was used. The significance of those differences was tested using ANOVA. To evaluate similarities and significance of clusters, a Multi-Dimensional Scaling was used. The tracks of 86.67% (N = 65 of the hatchlings from nests at illuminated areas departed from their correct trajectory. The distribution of trajectories was considered random (V = 19.4895, p > 0.05 only for tracks originating from artificially illuminated areas. The movement patterns of hatchlings from illuminated and non-illuminated areas differed significantly (F < 0.0001, p < 0.01. Consistent with this, two distinct groups were identified, one from illuminated and one from non-illuminated areas. Therefore, we conclude that artificial illumination impacts the orientation

Light exposure before learning improves memory consolidation at night

Science.gov (United States)

Shan, Li-Li; Guo, Hao; Song, Ning-Ning; Jia, Zheng-Ping; Hu, Xin-Tian; Huang, Jing-Fei; Ding, Yu-Qiang; Richter-Levine, Gal; Zhou, Qi-Xin; Xu, Lin

2015-01-01

Light is recently recognized as a modulator able to activate the hippocampus and modulate memory processing, but little is known about the molecular mechanisms. Here, we report that in mice, a short pulse of white light before learning dramatically improves consolidation of contextual fear memory during the night. The light exposure increases hippocampal active p21-activated kinase 1 (PAK1) and CA1 long-term potentiation (LTP). These light effects are abolished in PAK1 knockout and dominant-negative transgenic mice, but preserved by expression of constitutively active PAK1 in the hippocampus. Our results indicate that light can act as a switch of PAK1 activity that modulate CA1 LTP and thereby memory consolidation without affecting learning and short-term memory. PMID:26493375

Circadian variation of melatonin, light exposure, and diurnal preference in day and night shift workers of both sexes.

Science.gov (United States)

Papantoniou, Kyriaki; Pozo, Oscar J; Espinosa, Ana; Marcos, Josep; Castaño-Vinyals, Gemma; Basagaña, Xavier; Ribas, Ferran Calduch; Mirabent, Joan; Martín, Jordi; Carenys, Gemma; Martín, Celia Reyes; Middleton, Benita; Skene, Debra J; Kogevinas, Manolis

2014-07-01

Light-at-night has been shown in experimental studies to disrupt melatonin production but this has only partly been confirmed in studies of night shift workers. In this cross-sectional study, we examined the circadian variation of melatonin in relation to shift status, individual levels of light-at-night exposure, and diurnal preference, an attribute reflecting personal preference for activity in the morning or evening. One hundred and seventeen workers (75 night and 42 day) of both sexes, ages 22 to 64 years, were recruited from four companies. Participants collected urine samples from all voids over 24 hours and wore a data logger continuously recording their light exposure. Sociodemographic, occupational, lifestyle, and diurnal preference information were collected by interview. Concentrations of urinary 6-sulfatoxymelatonin (aMT6s), the main melatonin metabolite, were measured. Mean aMT6s levels were lower in night [10.9 ng/mg creatinine/hour; 95% confidence interval (CI), 9.5-12.6] compared with day workers (15.4; 95% CI, 12.3-19.3). The lowest aMT6s levels were observed in night workers with morning preference (6.4; 95% CI, 3.0-13.6). Peak time of aMT6s production occurred 3 hours later in night (08:42 hour, 95% CI, 07:48-09:42) compared with day workers (05:36 hour, 95% CI, 05:06-06:12). Phase delay was stronger among subjects with higher light-at-night exposure and number of nights worked. Night shift workers had lower levels and a delay in peak time of aMT6s production over a 24-hour period. Differences were modified by diurnal preference and intensity of light-at-night exposure. Night shift work affects levels and timing of melatonin production and both parameters may relate to future cancer risk. ©2014 American Association for Cancer Research.

Association between light exposure at night and nighttime blood pressure in the elderly independent of nocturnal urinary melatonin excretion.

Science.gov (United States)

Obayashi, Kenji; Saeki, Keigo; Iwamoto, Junko; Ikada, Yoshito; Kurumatani, Norio

2014-07-01

Circadian misalignment between internal and environmental rhythms dysregulates blood pressure (BP) variability because of disruption of the biological clock, resulting in increased nighttime BP. Although exposure to light-at-night is associated with the circadian misalignment, it remains unclear whether exposure to light-at-night in home settings is associated with nighttime BP. In this cross-sectional analysis of 528 elderly individuals (mean age: 72.8 years), we measured bedroom light intensity at 1-min intervals on two consecutive nights along with ambulatory BP, overnight urinary melatonin excretion and actigraphy. With regard to adjusted mean comparisons using analysis of covariance, the light-at-night group (average: ≥5 lux; n = 109) showed significantly higher nighttime systolic BP (SBP; adjusted mean: 120.8 vs. 116.5 mmHg, p = 0.01) and diastolic BP (70.1 vs. 67.1 mmHg, p light-at-night and nighttime BP in different cutoff values for light-at-night intensity (i.e. 3 and 10 lux). In conclusion, exposure to light-at-night in home settings is significantly associated with increased nighttime BP in elderly individuals independently of overnight urinary melatonin excretion. A 4.3 mmHg increase in nighttime SBP is associated with a 6.1% increase in total mortality, which corresponds to approximately 10 000 annual excess deaths in Japanese elderly population.

Short-wavelength attenuated polychromatic white light during work at night : Limited melatonin suppression without substantial decline of alertness

NARCIS (Netherlands)

van de Werken, Maan; Giménez, Marina C; de Vries, Bonnie; Beersma, Domien G M; Gordijn, Marijke C M

Exposure to light at night increases alertness, but light at night (especially short-wavelength light) also disrupts nocturnal physiology. Such disruption is thought to underlie medical problems for which shiftworkers have increased risk. In 33 male subjects we investigated whether short-wavelength

Globe at Night: From IYA2009 to the International Year of Light 2015 and Beyond

Science.gov (United States)

Walker, Constance Elaine; Pompea, Stephen M.; Sparks, Robert T.

2015-08-01

Citizen-science is a rewardingly inclusive way to bring awareness to the public on important issues like the disappearing starry night sky, its cause and solutions. Citizen-science can also provide meaningful, hands-on “science process” experiences for students. One program that does both is Globe at Night (www.globeatnight.org), an international campaign to raise public awareness of the impact of light pollution by having people measure night-sky brightness and submit observations via a “web app” on any smart device or computer. Additionally, 2 native mobile apps - Loss of the Night for iPhone & Android, and Dark Sky Meter for iPhone - support Globe at Night.Since 2006, more than 125,000 vetted measurements from 115 countries have been reported. For 2015 the campaign is offered as a 10-day observation window each month when the Moon is not up. To facilitate Globe at Night as an international project, the web app and other materials are in many languages. (See www.globeatnight.org/downloads.)Students and the general public can use the data to monitor levels of light pollution around the world, as well as understand light pollution’s effects on energy consumption, plants, wildlife, human health and our ability to enjoy a starry night sky. Projects have compared Globe at Night data with ground-truthing using meters for energy audits as well as with data on birds and bats, population density, satellite data and trends over time. Globe at Night tackles grand challenges and everyday problems. It provides resources for formal and informal educators to engage learners of all ages. It has 9 years of experience in best practices for data management, design, collection, visualization, interpretation, etc. It has externally evaluated its program, workshops, lesson plans and accompanying kit to explore reasons for participation, skills developed, impact of experiences and perceived outcomes. Three recent papers (Birriel et al. 2014; Kyba et al. 2013; 2015) verify the

Dim light at night prior to adolescence increases adult anxiety-like behaviors.

Science.gov (United States)

Cissé, Yasmine M; Peng, Juan; Nelson, Randy J

2016-01-01

Dim light at night (dLAN) disrupts circadian organization and influences adult behavior. We examined early dLAN exposure on adult affective responses. Beginning 3 (juvenile) or 5 weeks (adolescent) of age, mice were maintained in standard light-dark cycles or exposed to nightly dLAN (5 lx) for 5 weeks, then anxiety-like and fear responses were assessed. Hypothalami were collected around the clock to assess core clock genes. Exposure to dLAN at either age increased anxiety-like responses in adults. Clock and Rev-ERB expression were altered by exposure to dLAN. In contrast to adults, dLAN exposure during early life increases anxiety and fear behavior.

Exercise attenuates the metabolic effects of dim light at night.

Science.gov (United States)

Fonken, Laura K; Meléndez-Fernández, O Hecmarie; Weil, Zachary M; Nelson, Randy J

2014-01-30

Most organisms display circadian rhythms that coordinate complex physiological and behavioral processes to optimize energy acquisition, storage, and expenditure. Disruptions to the circadian system with environmental manipulations such as nighttime light exposure alter metabolic energy homeostasis. Exercise is known to strengthen circadian rhythms and to prevent weight gain. Therefore, we hypothesized providing mice a running wheel for voluntary exercise would buffer against the effects of light at night (LAN) on weight gain. Mice were maintained in either dark (LD) or dim (dLAN) nights and provided either a running wheel or a locked wheel. Mice exposed to dim, rather than dark, nights increased weight gain. Access to a functional running wheel prevented body mass gain in mice exposed to dLAN. Voluntary exercise appeared to limit weight gain independently of rescuing changes to the circadian system caused by dLAN; increases in daytime food intake induced by dLAN were not diminished by increased voluntary exercise. Furthermore, although all of the LD mice displayed a 24h rhythm in wheel running, nearly half (4 out of 9) of the dLAN mice did not display a dominant 24h rhythm in wheel running. These results indicate that voluntary exercise can prevent weight gain induced by dLAN without rescuing circadian rhythm disruptions. © 2013.

Response of bats to light with different spectra: light-shy and agile bat presence is affected by white and green, but not red light

NARCIS (Netherlands)

Spoelstra, K.; van Grunsven, Roy H. A.; Ramakers, J.J.C.; Ferguson, Kim B.; Raap, Thomas; Donners, Maurice; Veenendaal, Elmar M.; Visser, Marcel E.

Artificial light at night has shown a remarkable increase over the past decades. Effects are reported for many species groups, and include changes in presence, behaviour, physiology and life-history traits. Among these, bats are strongly affected, and how bat species react to light is likely to vary

Attraction of Chagas disease vectors (Triatominae) to artificial light sources in the canopy of primary Amazon rainforest.

Science.gov (United States)

Castro, Marcelo C M; Barrett, Toby V; Santos, Walter S; Abad-Franch, Fernando; Rafael, José A

2010-12-01

Adult triatomines occasionally fly into artificially lit premises in Amazonia. This can result in Trypanosoma cruzi transmission to humans either by direct contact or via foodstuff contamination, but the frequency of such behaviour has not been quantified. To address this issue, a light-trap was set 45 m above ground in primary rainforest near Manaus, state of Amazonas, Brazil and operated monthly for three consecutive nights over the course of one year (432 trap-hours). The most commonly caught reduviids were triatomines, including 38 Panstrongylus geniculatus, nine Panstrongylus lignarius, three Panstrongylus rufotuberculatus, five Rhodnius robustus, two Rhodnius pictipes, one Rhodnius amazonicus and 17 Eratyrus mucronatus. Males were collected more frequently than females. The only month without any catches was May. Attraction of most of the known local T. cruzi vectors to artificial light sources is common and year-round in the Amazon rainforest, implying that they may often invade premises built near forest edges and thus become involved in disease transmission. Consequently, effective Chagas disease prevention in Amazonia will require integrating entomological surveillance with the currently used epidemiological surveillance.

Attraction of Chagas disease vectors (Triatominae to artificial light sources in the canopy of primary Amazon rainforest

Directory of Open Access Journals (Sweden)

Marcelo CM Castro

2010-12-01

Full Text Available Adult triatomines occasionally fly into artificially lit premises in Amazonia. This can result in Trypanosoma cruzi transmission to humans either by direct contact or via foodstuff contamination, but the frequency of such behaviour has not been quantified. To address this issue, a light-trap was set 45 m above ground in primary rainforest near Manaus, state of Amazonas, Brazil and operated monthly for three consecutive nights over the course of one year (432 trap-hours. The most commonly caught reduviids were triatomines, including 38 Panstrongylus geniculatus, nine Panstrongylus lignarius, three Panstrongylus rufotuberculatus, five Rhodnius robustus, two Rhodnius pictipes, one Rhodnius amazonicus and 17 Eratyrus mucronatus. Males were collected more frequently than females. The only month without any catches was May. Attraction of most of the known local T. cruzi vectors to artificial light sources is common and year-round in the Amazon rainforest, implying that they may often invade premises built near forest edges and thus become involved in disease transmission. Consequently, effective Chagas disease prevention in Amazonia will require integrating entomological surveillance with the currently used epidemiological surveillance.

Driving home from the night shift: a bright light intervention study.

Science.gov (United States)

Weisgerber, Denise M; Nikol, Maria; Mistlberger, Ralph E

2017-02-01

Sleep deprivation (SD) impairs vigilance and increases the risk of driving accidents during the commute home after night work. Bright light (BL) can enhance alertness and cognitive performance. We examined the effects of BL (5600 lux) versus dim light (DL, 35 lux) at the end of a night awake on driving performance. Subjects (N = 19, 22.8 ± 4 ya) completed three conditions, counterbalanced for order at >1 week intervals. The two overnight SD conditions began in the lab at usual bedtime. After six hours in DL, subjects were exposed to 45 min BL or continued DL, and then completed a 44 min driving test (two lap circuit) in a high fidelity simulator. In the rested condition, subjects slept at home until habitual wakeup time, were transported to the lab and ∼45 min after wakeup, received BL and then the driving test. Oral temperature decreased while reaction time and sleepiness increased across both SD nights. BL suppressed salivary melatonin but had little or no effect on sleepiness or reaction time. SD markedly increased incidents and accidents. Five subjects (26%) sustained a terminal accident (eg, car flip) in the SD-DL condition, but none did so in the SD-BL or rested-BL conditions. Compared to SD-DL, SD-BL was associated with fewer incidents and accidents overall, and with better performance on the second lap of the circuit on several performance measures. BL at the end of a night shift may have potential as a countermeasure to improve driving following night work. Copyright © 2016 Elsevier B.V. All rights reserved.

Future lighting and the appearance of cities at night: A case study

Directory of Open Access Journals (Sweden)

Simon Rankel

2014-06-01

Full Text Available Future lighting solutions based on solid state lighting will transform the appearance of cities at night. They can be positioned and used in an urban environment in numerous ways. This article studies whether their future use in general outdoor lighting will positively affect people’s acceptance of urban space illuminated in this way. Two different lighting concepts were formed based on the innovative use of solid state lighting solutions. The first concept is based on plane lighting, and the second is based on a detailed depiction of architectural and urban elements. Lighting proposals were designed for five different city locations. They consider not only functional needs, but also urban planning and the architectural aspects of illumination. I present my study of the underlying core effects on the respondents through their assessment of the affective quality of graphic representations. My findings indicate that the respondents strongly agree with the assessment of the “pleasantness” and “arousal” variables of most proposals. However, the statistics show characteristic differences between the answers of both variables for both concepts. Direct comparison of the two concepts shows that the respondents’ attitudes towards a certain lighting concept also depend on their location in the city. This article emphasises the importance of the appearance of a city at night in developing future lighting strategies based on solid state light sources.

Lamp-lit bridges as dual light-traps for the night-swarming mayfly, Ephoron virgo: interaction of polarized and unpolarized light pollution.

Directory of Open Access Journals (Sweden)

Denes Szaz

Full Text Available Ecological photopollution created by artificial night lighting can alter animal behavior and lead to population declines and biodiversity loss. Polarized light pollution is a second type of photopollution that triggers water-seeking insects to ovisposit on smooth and dark man-made objects, because they simulate the polarization signatures of natural water bodies. We document a case study of the interaction of these two forms of photopollution by conducting observations and experiments near a lamp-lit bridge over the river Danube that attracts mass swarms of the mayfly Ephoron virgo away from the river to oviposit on the asphalt road of the bridge. Millions of mayflies swarmed near bridge-lights for two weeks. We found these swarms to be composed of 99% adult females performing their upstream compensatory flight and were attracted upward toward unpolarized bridge-lamp light, and away from the horizontally polarized light trail of the river. Imaging polarimetry confirmed that the asphalt surface of the bridge was strongly and horizontally polarized, providing a supernormal ovipositional cue to Ephoron virgo, while other parts of the bridge were poor polarizers of lamplight. Collectively, we confirm that Ephoron virgo is independently attracted to both unpolarized and polarized light sources, that both types of photopollution are being produced at the bridge, and that spatial patterns of swarming and oviposition are consistent with evolved behaviors being triggered maladaptively by these two types of light pollution. We suggest solutions to bridge and lighting design that should prevent or mitigate the impacts of such scenarios in the future. The detrimental impacts of such scenarios may extend beyond Ephoron virgo.

Lamp-lit bridges as dual light-traps for the night-swarming mayfly, Ephoron virgo: interaction of polarized and unpolarized light pollution.

Science.gov (United States)

Szaz, Denes; Horvath, Gabor; Barta, Andras; Robertson, Bruce A; Farkas, Alexandra; Egri, Adam; Tarjanyi, Nikolett; Racz, Gergely; Kriska, Gyorgy

2015-01-01

Ecological photopollution created by artificial night lighting can alter animal behavior and lead to population declines and biodiversity loss. Polarized light pollution is a second type of photopollution that triggers water-seeking insects to ovisposit on smooth and dark man-made objects, because they simulate the polarization signatures of natural water bodies. We document a case study of the interaction of these two forms of photopollution by conducting observations and experiments near a lamp-lit bridge over the river Danube that attracts mass swarms of the mayfly Ephoron virgo away from the river to oviposit on the asphalt road of the bridge. Millions of mayflies swarmed near bridge-lights for two weeks. We found these swarms to be composed of 99% adult females performing their upstream compensatory flight and were attracted upward toward unpolarized bridge-lamp light, and away from the horizontally polarized light trail of the river. Imaging polarimetry confirmed that the asphalt surface of the bridge was strongly and horizontally polarized, providing a supernormal ovipositional cue to Ephoron virgo, while other parts of the bridge were poor polarizers of lamplight. Collectively, we confirm that Ephoron virgo is independently attracted to both unpolarized and polarized light sources, that both types of photopollution are being produced at the bridge, and that spatial patterns of swarming and oviposition are consistent with evolved behaviors being triggered maladaptively by these two types of light pollution. We suggest solutions to bridge and lighting design that should prevent or mitigate the impacts of such scenarios in the future. The detrimental impacts of such scenarios may extend beyond Ephoron virgo.

Light pollution disrupts sleep in free-living animals.

Science.gov (United States)

Raap, Thomas; Pinxten, Rianne; Eens, Marcel

2015-09-04

Artificial lighting can alter individual behaviour, with often drastic and potentially negative effects on biological rhythms, daily activity and reproduction. Whether this is caused by a disruption of sleep, an important widespread behaviour enabling animals to recover from daily stress, is unclear. We tested the hypothesis that light pollution disrupts sleep by recording individual sleep behaviour of great tits, Parus major, that were roosting in dark nest-boxes and were exposed to light-emitting diode light the following night. Their behaviour was compared to that of control birds sleeping in dark nest-boxes on both nights. Artificial lighting caused experimental birds to wake up earlier, sleep less (-5%) and spent less time in the nest-box as they left their nest-box earlier in the morning. Experimental birds did not enter the nest-box or fall asleep later than controls. Although individuals in lit nest-boxes did not wake up more often nor decreased the length of their sleep bouts, females spent a greater proportion of the night awake. Our study provides the first direct proof that light pollution has a significant impact on sleep in free-living animals, in particular in the morning, and highlights a mechanism for potential effects of light pollution on fitness.

Natural and artificial spectral edges in exoplanets

Science.gov (United States)

Lingam, Manasvi; Loeb, Abraham

2017-09-01

Technological civilizations may rely upon large-scale photovoltaic arrays to harness energy from their host star. Photovoltaic materials, such as silicon, possess distinctive spectral features, including an 'artificial edge' that is characteristically shifted in wavelength shortwards of the 'red edge' of vegetation. Future observations of reflected light from exoplanets would be able to detect both natural and artificial edges photometrically, if a significant fraction of the planet's surface is covered by vegetation or photovoltaic arrays, respectively. The stellar energy thus tapped can be utilized for terraforming activities by transferring heat and light from the day side to the night side on tidally locked exoplanets, thereby producing detectable artefacts.

Association between nighttime artificial light pollution and sea turtle nest density along Florida coast: A geospatial study using VIIRS remote sensing data.

Science.gov (United States)

Hu, Zhiyong; Hu, Hongda; Huang, Yuxia

2018-08-01

Artificial lighting at night has becoming a new type of pollution posing an important anthropogenic environmental pressure on organisms. The objective of this research was to examine the potential association between nighttime artificial light pollution and nest densities of the three main sea turtle species along Florida beaches, including green turtles, loggerheads, and leatherbacks. Sea turtle survey data was obtained from the "Florida Statewide Nesting Beach Survey program". We used the new generation of satellite sensor "Visible Infrared Imaging Radiometer Suite (VIIRS)" (version 1 D/N Band) nighttime annual average radiance composite image data. We defined light pollution as artificial light brightness greater than 10% of the natural sky brightness above 45° of elevation (>1.14 × 10 -11 Wm -2 sr -1 ). We fitted a generalized linear model (GLM), a GLM with eigenvectors spatial filtering (GLM-ESF), and a generalized estimating equations (GEE) approach for each species to examine the potential correlation of nest density with light pollution. Our models are robust and reliable in terms of the ability to deal with data distribution and spatial autocorrelation (SA) issues violating model assumptions. All three models found that nest density is significantly negatively correlated with light pollution for each sea turtle species: the higher light pollution, the lower nest density. The two spatially extended models (GLM-ESF and GEE) show that light pollution influences nest density in a descending order from green turtles, to loggerheads, and then to leatherbacks. The research findings have an implication for sea turtle conservation policy and ordinance making. Near-coastal lights-out ordinances and other approaches to shield lights can protect sea turtles and their nests. The VIIRS DNB light data, having significant improvements over comparable data by its predecessor, the DMSP-OLS, shows promise for continued and improved research about ecological effects of

Dim light at night disturbs the daily sleep-wake cycle in the rat

NARCIS (Netherlands)

Stenvers, Dirk Jan; van Dorp, Rick; Foppen, Ewout; Mendoza, Jorge; Opperhuizen, Anne-Loes; Fliers, Eric; Bisschop, Peter H; Meijer, Johanna H; Kalsbeek, A.; Deboer, Tom

2016-01-01

Exposure to light at night (LAN) is associated with insomnia in humans. Light provides the main input to the master clock in the hypothalamic suprachiasmatic nucleus (SCN) that coordinates the sleep-wake cycle. We aimed to develop a rodent model for the effects of LAN on sleep. Therefore, we exposed

The Citizen-Scientist as Data Collector: GLOBE at Night, Part 2

Science.gov (United States)

Walker, C. E.; Pompea, S. M.; Ward, D.; Henderson, S.; Meymaris, K.; Gallagher, S.; Salisbury, D.

2006-12-01

An innovative program to realize light pollution education on two continents via Internet 2-based videoconferencing was begun 4 years ago by the National Optical Astronomy Observatory. Bilingual science teachers and their students in Arizona and Chile recorded the brightness of the night sky by matching its appearance toward the constellation Orion with one of 6 stellar maps of limiting magnitude. Students from both hemispheres would report their findings via videoconferences. In the last year the program has evolved in collaboration with UCAR and other partners into an international, user-friendly, web-based science event open to anyone in the world, known as GLOBE at Night. GLOBE at Night uses the same design to observe and record the visible stars toward Orion, as a means of measuring light pollution in a given location. The inaugural event occurred over 11 nights last March, when 18,000 citizen- scientists made over 4,500 observations from 96 countries. Analysis of the GLOBE at Night data set found that the brighter skies corresponded to areas with higher population density, and that most observations were taken in a location with some light pollution. The data also tended to confirm that satellite data is reliable in assessing light pollution. This session will describe our program to incorporate more technology into the GLOBE at Night program. Citizen-scientists will use sky quality meters (visible light photometers), calibrated digital photography, and GPS as a means to measure and map more accurately the brightness of the sky at selected urban and rural sites. This extension of the program is designed to aid further in teaching about the impact of artificial lighting on local environments and the ongoing loss of a dark night sky as a natural resource. We will also describe how detailed maps of selected urban areas can be used to assess lighting design, safety considerations and energy usage. Given the widespread interest in the inaugural GLOBE at Night

Impact of Exposure to Dim Light at Night on Sleep in Female and Comparison with Male Subjects.

Science.gov (United States)

Cho, Chul-Hyun; Yoon, Ho-Kyoung; Kang, Seung-Gul; Kim, Leen; Lee, Eun-Il; Lee, Heon-Jeong

2018-03-19

Light pollution has become a social and health issue. We performed an experimental study to investigate impact of dim light at night (dLAN) on sleep in female subjects, with measurement of salivary melatonin. The 25 female subjects (Group A: 12; Group B: 13 subjects) underwent a nocturnal polysomnography (NPSG) session with no light (Night 1) followed by an NPSG session randomly assigned to two conditions (Group A: 5; Group B: 10 lux) during a whole night of sleep (Night 2). Salivary melatonin was measured before and after sleep on each night. For further investigation, the female and male subjects of our previous study were collected (48 subjects), and differences according to gender were compared. dLAN during sleep was significantly associated with decreased total sleep time (TST; F=4.818, p=0.039), sleep efficiency (SE; F=5.072, p=0.034), and Stage R latency (F=4.664, p=0.041) for female subjects, and decreased TST (F=14.971, pfemale as well as in merged subjects. REM sleep showed a pronounced increase under 10 lux than under 5 lux in merged subjects, suggesting the possibility of subtle influences of dLAN on REM sleep.

Limited evidence for affective and diurnal rhythm responses to dim light-at-night in male and female C57Bl/6 mice.

Science.gov (United States)

Cleary-Gaffney, Michael; Coogan, Andrew N

2018-05-15

Circadian rhythms are recurring patterns in a range of behavioural, physiological and molecular parameters that display periods of near 24 h, and are underpinned by an endogenous biological timekeeping system. Circadian clocks are increasingly recognised as being key for health. Environmental light is the key stimulus that synchronises the internal circadian system with the external time cues. There are emergent health concerns regarding increasing worldwide prevalence of electric lighting, especially man-made light-at-night, and light's impact on the circadian system may be central to these effects. A number of previous studies have demonstrated increased depression-like behaviour in various rodent experimental models exposed to dim light-at-night. In this study we set out to study the impact of dim light-at-night on circadian and affective behaviours in C57Bl/6 mice. We set out specifically to examine the impact of sex on light at night's effects, as well as the impact of housing conditions. We report minimal impact of light-at-night on circadian and affective behaviours, as measured by the tail suspension test, the forced swim test, the sucrose preference test and the elevated plus maze. Light-at-night was also not associated with an increase in body weight, but was associated with a decrease in the cell proliferation marker Ki-67 in the dentate gyrus. In summary, we conclude that experimental contextual factors, such as model species or strain, may be considerable importance in the investigation of the impact of light at night on mood-related parameters. Copyright © 2018 Elsevier Inc. All rights reserved.

Adaptive integration of daylight and artificial lighting

DEFF Research Database (Denmark)

Petersen, Kjell Yngve

2016-01-01

Daylight is dynamic and dependent upon weather conditions; unfolding with both subtle and dramatic variations in qualities of light. Through a building’s apertures, daylight creates a connection between the space inside and the world outside. The aperture or window itself constitutes the frame...... with the world. In contrast to fluctuating daylight, a specific distinctive feature of artificial light has been – until very recently – its constancy in colour and intensity. However, by virtue of the technological convertibility of LEDs in concert with digital control systems, LEDs are capable of dynamically...... producing variations in colour and intensity in ways that correspond to our experiences of the daylight. Daylight and artificial lighting are thus positioned in a new relationship to one another. Metaphorically, one can think of the adaptive software as ‘digital weather’ – as a self-generating and shifting...

Dim light at night interferes with the development of the short-day phenotype and impairs cell-mediated immunity in Siberian hamsters (Phodopus sungorus).

Science.gov (United States)

Aubrecht, Taryn G; Weil, Zachary M; Nelson, Randy J

2014-10-01

Winter is a challenging time to survive and breed outside of the tropics. Animals use day length (photoperiod) to regulate seasonally appropriate adaptations in anticipation of challenging winter conditions. The net result of these photoperiod-mediated adjustments is enhanced immune function and increased survival. Thus, the ability to discriminate day length information is critical for survival and reproduction in small animals. However, during the past century, urban and suburban development has rapidly expanded and filled the night sky with light from various sources, obscuring crucial light-dark signals, which alters physiological interpretation of day lengths. Furthermore, reduced space, increased proximity to people, and the presence of light at night may act as stressors for small animals. Whereas acute stressors typically enhance immune responses, chronic exposure to stressors often impairs immune responses. Therefore, we hypothesized that the combination of dim light at night and chronic stress interferes with enhanced cell-mediated immunity observed during short days. Siberian hamsters (Phodopus sungorus) were assigned to short or long days with dark nights (0 lux) or dim (5 lux) light at night for 10 weeks. Following 2 weeks of chronic restraint (6 hr/day), a model of chronic stress, delayed type hypersensitivity (DTH) responses were assessed. Both dim light at night and restraint reduced the DTH response. Dim light at night during long nights produced an intermediate short day phenotype. These results suggest the constant presence of light at night could negatively affect survival of photoperiodic rodents by disrupting the timing of breeding and immune responses. © 2014 Wiley Periodicals, Inc.

The Value of Darkness : A Moral Framework for Urban Nighttime Lighting

NARCIS (Netherlands)

Stone, T.W.

2017-01-01

The adverse effects of artificial nighttime lighting, known as light pollution, are emerging as an important environmental issue. To address these effects, current scientific research focuses mainly on identifying what is bad or undesirable about certain types and uses of lighting at night. This

Response of bats to light with different spectra

NARCIS (Netherlands)

Spoelstra, Kamiel; Grunsven, van Roy H.A.; Ramakers, Jip J.C.; Ferguson, Kim B.; Raap, Thomas; Donners, Maurice; Veenendaal, Elmar M.; Visser, Marcel E.

2017-01-01

Artificial light at night has shown a remarkable increase over the past decades. Effects are reported for many species groups, and include changes in presence, behaviour, physiology and life-history traits. Among these, bats are strongly affected, and how bat species react to light is likely to

Light at night acutely impairs glucose tolerance in a time-, intensity- and wavelength-dependent manner in rats.

Science.gov (United States)

Opperhuizen, Anne-Loes; Stenvers, Dirk J; Jansen, Remi D; Foppen, Ewout; Fliers, Eric; Kalsbeek, Andries

2017-07-01

Exposure to light at night (LAN) has increased dramatically in recent decades. Animal studies have shown that chronic dim LAN induced obesity and glucose intolerance. Furthermore, several studies in humans have demonstrated that chronic exposure to artificial LAN may have adverse health effects with an increased risk of metabolic disorders, including type 2 diabetes. It is well-known that acute exposure to LAN affects biological clock function, hormone secretion and the activity of the autonomic nervous system, but data on the effects of LAN on glucose homeostasis are lacking. This study aimed to investigate the acute effects of LAN on glucose metabolism. Male Wistar rats were subjected to i.v. glucose or insulin tolerance tests while exposed to 2 h of LAN in the early or late dark phase. In subsequent experiments, different light intensities and wavelengths were used. LAN exposure early in the dark phase at ZT15 caused increased glucose responses during the first 20 min after glucose infusion (p light of 50 and 150 lx induced greater glucose responses than 5 and 20 lx, whereas all intensities other than 5 lx reduced locomotor activity. Green light induced glucose intolerance, but red and blue light did not, suggesting the involvement of a specific retina-brain pathway. Together, these data show that exposure to LAN has acute adverse effects on glucose metabolism in a time-, intensity- and wavelength-dependent manner.

Restless roosts: Light pollution affects behavior, sleep, and physiology in a free-living songbird.

Science.gov (United States)

Ouyang, Jenny Q; de Jong, Maaike; van Grunsven, Roy H A; Matson, Kevin D; Haussmann, Mark F; Meerlo, Peter; Visser, Marcel E; Spoelstra, Kamiel

2017-11-01

The natural nighttime environment is increasingly polluted by artificial light. Several studies have linked artificial light at night to negative impacts on human health. In free-living animals, light pollution is associated with changes in circadian, reproductive, and social behavior, but whether these animals also suffer from physiologic costs remains unknown. To fill this gap, we made use of a unique network of field sites which are either completely unlit (control), or are artificially illuminated with white, green, or red light. We monitored nighttime activity of adult great tits, Parus major, and related this activity to within-individual changes in physiologic indices. Because altered nighttime activity as a result of light pollution may affect health and well-being, we measured oxalic acid concentrations as a biomarker for sleep restriction, acute phase protein concentrations and malaria infection as indices of immune function, and telomere lengths as an overall measure of metabolic costs. Compared to other treatments, individuals roosting in the white light were much more active at night. In these individuals, oxalic acid decreased over the course of the study. We also found that individuals roosting in the white light treatment had a higher probability of malaria infection. Our results indicate that white light at night increases nighttime activity levels and sleep debt and affects disease dynamics in a free-living songbird. Our study offers the first evidence of detrimental effects of light pollution on the health of free-ranging wild animals. © 2017 John Wiley & Sons Ltd.

Effect of Housing Rats in Dim Light or Long Nights on Heart Rate

OpenAIRE

Azar, Toni A; Sharp, Jody L; Lawson, David M

2008-01-01

Housing laboratory animals under lighting conditions that more closely mimic the natural environment may improve their wellbeing. This study examined the effects of dim light or a long-night photocycle on resting heart rate (HR) of rats and their HR responses to acute procedures. Male and female Sprague–Dawley (SD) and spontaneously hypertensive (SHR) rats, instrumented with radiotelemetry transmitters and housed individually under a 12:12-h light:dark photocycle with 10 lx illumination (dim ...

Artificial light harvesting by dimerized Möbius ring

Science.gov (United States)

Xu, Lei; Gong, Z. R.; Tao, Ming-Jie; Ai, Qing

2018-04-01

We theoretically study artificial light harvesting by a Möbius ring. When the donors in the ring are dimerized, the energies of the donor ring are split into two subbands. Because of the nontrivial Möbius boundary condition, both the photon and acceptor are coupled to all collective-excitation modes in the donor ring. Therefore, the quantum dynamics in the light harvesting is subtly influenced by dimerization in the Möbius ring. It is discovered that energy transfer is more efficient in a dimerized ring than that in an equally spaced ring. This discovery is also confirmed by a calculation with the perturbation theory, which is equivalent to the Wigner-Weisskopf approximation. Our findings may be beneficial to the optimal design of artificial light harvesting.

Parental Exposure to Dim Light at Night Prior to Mating Alters Offspring Adaptive Immunity.

Science.gov (United States)

Cissé, Yasmine M; Russart, Kathryn L G; Nelson, Randy J

2017-03-31

Exposure to dim light at night (dLAN) disrupts natural light/dark cycles and impairs endogenous circadian rhythms necessary to maintain optimal biological function, including the endocrine and immune systems. We have previously demonstrated that white dLAN compromises innate and cell mediated immune responses in adult Siberian hamsters (Phodopus sungorus). We hypothesized that dLAN has transgenerational influences on immune function. Adult male and female Siberian hamsters were exposed to either dark nights (DARK) or dLAN (~5 lux) for 9 weeks, then paired in full factorial design, mated, and thereafter housed under dark nights. Offspring were gestated and reared in dark nights, then tested as adults for cell-mediated and humoral immunity. Maternal exposure to dLAN dampened delayed type hypersensitivity (DTH) responses in male offspring. Maternal and paternal exposure to dLAN reduced DTH responses in female offspring. IgG antibodies to a novel antigen were elevated in offspring of dams exposed to dLAN. Paternal exposure to dLAN decreased splenic endocrine receptor expression and global methylation in a parental sex-specific manner. Together, these data suggest that exposure to dLAN has transgenerational effects on endocrine-immune function that may be mediated by global alterations in the epigenetic landscape of immune tissues.

Modelling of light pollution in suburban areas using remotely sensed imagery and GIS.

Science.gov (United States)

Chalkias, C; Petrakis, M; Psiloglou, B; Lianou, M

2006-04-01

This paper describes a methodology for modelling light pollution using geographical information systems (GIS) and remote sensing (RS) technology. The proposed approach attempts to address the issue of environmental assessment in sensitive suburban areas. The modern way of life in developing countries is conductive to environmental degradation in urban and suburban areas. One specific parameter for this degradation is light pollution due to intense artificial night lighting. This paper aims to assess this parameter for the Athens metropolitan area, using modern analytical and data capturing technologies. For this purpose, night-time satellite images and analogue maps have been used in order to create the spatial database of the GIS for the study area. Using GIS advanced analytical functionality, visibility analysis was implemented. The outputs for this analysis are a series of maps reflecting direct and indirect light pollution around the city of Athens. Direct light pollution corresponds to optical contact with artificial night light sources, while indirect light pollution corresponds to optical contact with the sky glow above the city. Additionally, the assessment of light pollution in different periods allows for dynamic evaluation of the phenomenon. The case study demonstrates high levels of light pollution in Athens suburban areas and its increase over the last decade.

Long-term effects of chronic light pollution on seasonal functions of European blackbirds (Turdus merula).

Science.gov (United States)

Dominoni, Davide M; Quetting, Michael; Partecke, Jesko

2013-01-01

Light pollution is known to affect important biological functions of wild animals, including daily and annual cycles. However, knowledge about long-term effects of chronic exposure to artificial light at night is still very limited. Here we present data on reproductive physiology, molt and locomotor activity during two-year cycles of European blackbirds (Turdus merula) exposed to either dark nights or 0.3 lux at night. As expected, control birds kept under dark nights exhibited two regular testicular and testosterone cycles during the two-year experiment. Control urban birds developed testes faster than their control rural conspecifics. Conversely, while in the first year blackbirds exposed to light at night showed a normal but earlier gonadal cycle compared to control birds, during the second year the reproductive system did not develop at all: both testicular size and testosterone concentration were at baseline levels in all birds. In addition, molt sequence in light-treated birds was more irregular than in control birds in both years. Analysis of locomotor activity showed that birds were still synchronized to the underlying light-dark cycle. We suggest that the lack of reproductive activity and irregular molt progression were possibly the results of i) birds being stuck in a photorefractory state and/or ii) chronic stress. Our data show that chronic low intensities of light at night can dramatically affect the reproductive system. Future studies are needed in order to investigate if and how urban animals avoid such negative impact and to elucidate the physiological mechanisms behind these profound long-term effects of artificial light at night. Finally we call for collaboration between scientists and policy makers to limit the impact of light pollution on animals and ecosystems.

Temporal dynamics of circadian phase shifting response to consecutive night shifts in healthcare workers: role of light-dark exposure.

Science.gov (United States)

Stone, Julia E; Sletten, Tracey L; Magee, Michelle; Ganesan, Saranea; Mulhall, Megan D; Collins, Allison; Howard, Mark; Lockley, Steven W; Rajaratnam, Shantha M W

2018-03-28

Shift work is highly prevalent and is associated with significant adverse health impacts. There is substantial inter-individual variability in the way the circadian clock responds to changing shift cycles. The mechanisms underlying this variability are not well understood. We tested the hypothesis that light-dark exposure is a significant contributor to this variability; when combined with diurnal preference, the relative timing of light exposure accounted for 71% of individual variability in circadian phase response to night shift work. These results will drive development of personalised approaches to manage circadian disruption among shift workers and other vulnerable populations to potentially reduce the increased risk of disease in these populations. Night shift workers show highly variable rates of circadian adaptation. This study examined the relationship between light exposure patterns and the magnitude of circadian phase resetting in response to night shift work. In 21 participants (nursing and medical staff in an intensive care unit) circadian phase was measured using 6-sulphatoxymelatonin at baseline (day/evening shifts or days off) and after 3-4 consecutive night shifts. Daily light exposure was examined relative to individual circadian phase to quantify light intensity in the phase delay and phase advance portions of the light phase response curve (PRC). There was substantial inter-individual variability in the direction and magnitude of phase shift after three or four consecutive night shifts (mean phase delay -1:08 ± 1:31 h; range -3:43 h delay to +3:07 h phase advance). The relative difference in the distribution of light relative to the PRC combined with diurnal preference accounted for 71% of the variability in phase shift. Regression analysis incorporating these factors estimated phase shift to within ±60 min in 85% of participants. No participants met criteria for partial adaptation to night work after three or four consecutive night

Experimental illumination of natural habitat--an experimental set-up to assess the direct and indirect ecological consequences of artificial light of different spectral composition.

Science.gov (United States)

Spoelstra, Kamiel; van Grunsven, Roy H A; Donners, Maurice; Gienapp, Phillip; Huigens, Martinus E; Slaterus, Roy; Berendse, Frank; Visser, Marcel E; Veenendaal, Elmar

2015-05-05

Artificial night-time illumination of natural habitats has increased dramatically over the past few decades. Generally, studies that assess the impact of artificial light on various species in the wild make use of existing illumination and are therefore correlative. Moreover, studies mostly focus on short-term consequences at the individual level, rather than long-term consequences at the population and community level-thereby ignoring possible unknown cascading effects in ecosystems. The recent change to LED lighting has opened up the exciting possibility to use light with a custom spectral composition, thereby potentially reducing the negative impact of artificial light. We describe here a large-scale, ecosystem-wide study where we experimentally illuminate forest-edge habitat with different spectral composition, replicated eight times. Monitoring of species is being performed according to rigid protocols, in part using a citizen-science-based approach, and automated where possible. Simultaneously, we specifically look at alterations in behaviour, such as changes in activity, and daily and seasonal timing. In our set-up, we have so far observed that experimental lights facilitate foraging activity of pipistrelle bats, suppress activity of wood mice and have effects on birds at the community level, which vary with spectral composition. Thus far, we have not observed effects on moth populations, but these and many other effects may surface only after a longer period of time. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Randomised controlled trial of the efficacy of a blue-enriched light intervention to improve alertness and performance in night shift workers.

Science.gov (United States)

Sletten, Tracey L; Ftouni, Suzanne; Nicholas, Christian L; Magee, Michelle; Grunstein, Ronald R; Ferguson, Sally; Kennaway, David J; O'Brien, Darren; Lockley, Steven W; Rajaratnam, Shantha M W

2017-11-01

Night workers often experience high levels of sleepiness due to misalignment of the sleep-wake cycle from the circadian pacemaker, in addition to acute and chronic sleep loss. Exposure to light, in particular short wavelength light, can improve alertness and neurobehavioural performance. This randomised controlled trial examined the efficacy of blue-enriched polychromatic light to improve alertness and neurobehavioural performance in night workers. Participants were 71 night shift workers (42 males; 32.8±10.5 years) who worked at least 6 hours between 22:00 and 08:00 hours. Sleep-wake logs and wrist actigraphy were collected for 1-3 weeks, followed by 48-hour urine collection to measure the circadian 6-sulphatoxymelatonin (aMT6s) rhythm. On the night following at least two consecutive night shifts, workers attended a simulated night shift in the laboratory which included subjective and objective assessments of sleepiness and performance. Workers were randomly assigned for exposure to one of two treatment conditions from 23:00 hours to 07:00 hours: blue-enriched white light (17 000 K, 89 lux; n=36) or standard white light (4000 K, 84 lux; n=35). Subjective and objective sleepiness increased during the night shift in both light conditions (pnight shift workers, further research is needed in the selection of light properties to maximise the benefits. The Australian New Zealand Clinical Trials Registry ACTRN12610000097044 (https://www.anzctr.org.au/Trial/Registration/TrialReview.aspx?id=320845&isReview=true). © Article author(s) (or their employer(s) unless otherwise stated in the text of the article) 2017. All rights reserved. No commercial use is permitted unless otherwise expressly granted.

Assessment and the feasibility of improving the artificial lighting system in technical services workshop located in the Fourth South Pars Gas Refinery

Directory of Open Access Journals (Sweden)

masoud shafiee motlagh

2015-09-01

Full Text Available Background & Objectives: Desirable and ergonomic lighting in the workplaces has a significant impact on the visual effects and improve the efficiency and productivity of employees. This study aims to evaluate the lighting system and feasibility of improving the artificial lighting system for comfort lighting in the workshop of the Fourth South Pars Gas Refinery. Methods: In this descriptive-analytical study, the environmental conditions of the studied workshop were evaluated and the illuminance was measured in both day and night times at 216 points. Based on lighting measurements, a site map was provided. Further, based on current conditions of the workshop, illuminance was estimated using DIALux 4.12 lighting calculations software. In regard to the national recommended limits for industrial lighting and the current luminaires, the different practical, accessible and low cost solutions were presented. Using the mentioned software, the share of each proposed solutions for improving workshop lighting were estimated. Results: The results showed that illuminance of the workshop in day and night times were equal to 197±71.5lx and 160±50.6 lx, respectively. The same results were also acquired by software calculations. Based on the results, lighting system was considered as undesirable lighting system along with need to modifications. Workshop lighting can increase between 260 lx to 405 lx through employing the proposed solutions based on the software predictions. Conclusion: The results confirmed that the low cost and simple solutions can significantly be improved the ergonomic and comfort lighting in the workplace. The use of the specialized tools calculations by experts and designers can be also facilitated the conducting feasibility reliable.

Day-light-controlled artificial lighting a potential energy saver": right interior light by sky luninance trracking

NARCIS (Netherlands)

Rutten, A.J.F.; Mills, Evan

1991-01-01

The energy consumption in office buildings can considerably be cut, if daylight is used as task lighting. A conservative estimate - starting from existing knowledge and calculation methods - gives a potential saving of 460 GWh a year or 46 % of the electricity costs for artificial lighting in Dutch

Atmosphere self-cleaning under humidity conditions and influence of the snowflakes and artificial light interaction for water dissociation simulated by the means of COMSOL

Science.gov (United States)

Cocean, A.; Cocean, I.; Cazacu, M. M.; Bulai, G.; Iacomi, F.; Gurlui, S.

2018-06-01

The self-cleaning of the atmosphere under humidity conditions is observed due to the change in emission intensity when chemical traces are investigated with DARLIOES - the advanced LIDAR based on space- and time-resolved RAMAN and breakdown spectroscopy in conditions of consistent humidity of atmosphere. The determination was performed during the night, in the wintertime under conditions of high humidity and snowfall, in urban area of Iasi. The change in chemical composition of the atmosphere detected was assumed to different chemical reactions involving presence of the water. Water dissociation that was registered during spectral measurements is explained by a simulation of the interaction between artificial light and snowflakes - virtually designed in a spherical geometry - in a wet air environment, using COMSOL Multiphysics software. The aim of the study is to explain the decrease or elimination of some of the toxic trace chemical compounds in the process of self-cleaning in other conditions than the sun light interaction for further finding application for air cleaning under artificial conditions.

Protecting the Melatonin Rhythm through Circadian Healthy Light Exposure

Directory of Open Access Journals (Sweden)

Maria Angeles Bonmati-Carrion

2014-12-01

Full Text Available Currently, in developed countries, nights are excessively illuminated (light at night, whereas daytime is mainly spent indoors, and thus people are exposed to much lower light intensities than under natural conditions. In spite of the positive impact of artificial light, we pay a price for the easy access to light during the night: disorganization of our circadian system or chronodisruption (CD, including perturbations in melatonin rhythm. Epidemiological studies show that CD is associated with an increased incidence of diabetes, obesity, heart disease, cognitive and affective impairment, premature aging and some types of cancer. Knowledge of retinal photoreceptors and the discovery of melanopsin in some ganglion cells demonstrate that light intensity, timing and spectrum must be considered to keep the biological clock properly entrained. Importantly, not all wavelengths of light are equally chronodisrupting. Blue light, which is particularly beneficial during the daytime, seems to be more disruptive at night, and induces the strongest melatonin inhibition. Nocturnal blue light exposure is currently increasing, due to the proliferation of energy-efficient lighting (LEDs and electronic devices. Thus, the development of lighting systems that preserve the melatonin rhythm could reduce the health risks induced by chronodisruption. This review addresses the state of the art regarding the crosstalk between light and the circadian system.

Sky luminance research imperative for adequate ciontrol of temporary supplementary artificial lighting installations

NARCIS (Netherlands)

Rutten, A.J.F.

1994-01-01

The energy consumption in Dutch office buildings can be cut considerably if daylight is used as task lighting. A conservative estimate gives a potential saving of 46% on the electricity costs for artificial lighting. The problem of photo-electric control of artificial lighting supplementing the

Protection of Hawaii's Observatories from Light Pollution

Science.gov (United States)

Wainscoat, Richard J.

2018-01-01

Maunakea Observatory, located on the island of Hawaii, is among the world darkest sites for astronomy. Strong efforts to preserve the dark night sky over the last forty years have proven successful. Artificial light presently adds only approximately 2% to the natural night sky brightness. The techniques being used to protect Maunakea from light pollution will be described, along with the challenges that are now being faced.Haleakala Observatory, located on the island of Maui, is also an excellent observing site, and is among the best sites in the United States. Lighting restrictions in Maui County are much weaker, and consequently, the night sky above Haleakala is less well protected. Haleakala is closer to Honolulu and the island of Oahu (population approximately 1 million), and the glow from Oahu makes the northwestern sky brighter.Much of the lighting across most of the United States, including Hawaii, is presently being converted to LED lighting. This provides an opportunity to replace existing poorly shielded lights with properly shielded LED fixtures, but careful spectral management is essential. It is critically important to only use LED lighting that is deficient in blue and green light. LED lighting also is easy to dim. Dimming of lights later at night, when there is no need for brighter lighting, is an important tool for reducing light pollution.Techniques used to protect astronomical observatories from light pollution are similar to the techniques that must be used to protect animals that are affected by light at night, such as endangered birds and turtles. These same techniques are compatible with recent human health related lighting recommendations from the American Medical Association.

A single night light exposure acutely alters hormonal and metabolic responses in healthy participants

Directory of Open Access Journals (Sweden)

Mohammed S Albreiki

2017-01-01

Full Text Available Many animal studies have reported an association between melatonin suppression and the disturbance of metabolic responses; yet, few human studies have investigated bright light effects on metabolic and hormonal responses at night. This study investigated the impact of light on plasma hormones and metabolites prior to, and after, an evening meal in healthy participants. Seventeen healthy participants, 8 females (22.2 ± 2.59 years, mean ± s.d. and 9 males (22.8 ± 3.5 years were randomised to a two-way cross-over design protocol; dim light (DL (500 lux sessions, separated by at least seven days. Saliva and plasma samples were collected prior to and after a standard evening meal at specific intervals. Plasma non-esterified fatty acid (NEFA levels were significantly higher pre-meal in DL compared to BL (P < 0.01. Plasma glucose and insulin levels were significantly greater post-meal in the BL compared to DL session (P = 0.02, P = 0.001, respectively. Salivary melatonin levels were significantly higher in the DL compared to those in BL session (P = 0.005. BL at night was associated with significant increases in plasma glucose and insulin suggestive of glucose intolerance and insulin insensitivity. Raised pre-prandial NEFA levels may be due to changes in insulin sensitivity or the presence of melatonin and/or light at night. Plasma triglyceride (TAG levels were the same in both sessions. These results may explain some of the health issues reported in shift workers; however, further studies are needed to elucidate the cause of these metabolic changes.

Energy savings due to daylight and artificial lighting integration in office buildings in hot climate

Energy Technology Data Exchange (ETDEWEB)

Al-Ashwal, Nagib T. [Sana' a University, Sana' a (Yemen); Budaiwi, Ismail M. [King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia)

2011-07-01

Reducing energy consumption while maintaining acceptable environmental quality in buildings has been a challenging task for building professionals. In office buildings, artificial lighting systems are a major consumer of energy and can significantly contribute to building cooling load. Furthermore, although reliable, artificial lighting does not necessarily provide the required quality of lighting. Significant improvement in lighting quality and energy consumption can be achieved by proper integration of daylight and artificial lighting. The objective of this study is to investigate the energy performance of office buildings resulting from daylight and artificial lighting integration in hot climates. A parametric analysis is conducted to find the impact of different window design parameters, including window area, height and glazing type, on building energy performance. Results have shown that as much as 35% reduction in lighting energy consumption and 13% reduction in total energy consumption can be obtained when proper daylighting and artificial lighting integration is achieved.

Dim light at night increases depressive-like responses in male C3H/HeNHsd mice.

Science.gov (United States)

Fonken, Laura K; Nelson, Randy J

2013-04-15

Daily patterns of light exposure have become increasingly variable since the widespread adoption of electrical lighting during the 20th century. Seasonal fluctuations in light exposure, shift-work, and transmeridian travel are all associated with alterations in mood. These studies implicate fluctuations in environmental lighting in the development of depressive disorders. Here we argue that exposure to light at night (LAN) may be causally linked to depression. Male C3H/HeNHsd mice, which produce nocturnal melatonin, were housed in either a standard light/dark (LD) cycle or exposed to nightly dim (5 lux) LAN (dLAN). After four weeks in lighting conditions mice underwent behavioral testing and hippocampal tissue was collected at the termination of the study for qPCR. Here were report that mice exposed to dLAN increase depressive-like responses in both a sucrose anhedonia and forced swim test. In contrast to findings in diurnal grass rats, dLAN mice perform comparably to mice housed under dark nights in a hippocampus-dependent learning and memory task. TNFα and IL1β gene expression do not differ between groups, demonstrating that changes in these pro-inflammatory cytokines do not mediate dLAN induced depressive-like responses in mice. BDNF expression is reduced in the hippocampus of mice exposed to dLAN. These results indicate that low levels of LAN can alter mood in mice. This study along with previous work implicates LAN as a potential factor contributing to depression. Further understanding of the mechanisms through which LAN contributes to changes in mood is important for characterizing and treating depressive disorders. Copyright © 2013 Elsevier B.V. All rights reserved.

An Exploration into Integrating Daylight and Artificial Light via an Observational Instrument

DEFF Research Database (Denmark)

Petersen, Kjell Yngve; Søndergaard, Karin

2015-01-01

An Exploration into Integrating Daylight and Artificial Light via an Observational Instrument Daylight is dynamic and dependent upon weather conditions; unfolding with both subtle and dramatic variations in qualities of light. Through a building’s apertures, daylight creates a connection between...... abstract and blurred phenomena, these diffused luminous reflections rouse us into interactions with the world. In this book we are interested in identifying the qualitative parameters involved in the integration of dynamic artificial lighting and daylight; the latter being already highly dynamic by nature...... that examine how the dynamic artificial lighting in the observational instrument unfolds during the changing of the daylight situations that are generated by the weather outside. This research employs the concept of coupling between interior and exterior, in order to identify a spectrum of design parameters...

Estimation Methodology for the Electricity Consumption with the Daylight- and Occupancy-Controlled Artificial Lighting

DEFF Research Database (Denmark)

Larsen, Olena Kalyanova; Jensen, Rasmus Lund; Strømberg, Ida Kristine

2017-01-01

Artificial lighting represents 15-30% of the total electricity consumption in buildings in Scandinavia. It is possible to avoid a large share of electricity use for lighting by application of daylight control systems for artificial lighting. Existing methodology for estimation of electricity...... consumption with application of such control systems in Norway is based on Norwegian standard NS 3031:2014 and can only provide results from a rough estimate. This paper aims to introduce a new estimation methodology for the electricity usage with the daylight- and occupancy-controlled artificial lighting...

Measurements of light at night (LAN) for a sample of female school teachers

Science.gov (United States)

Rea, Mark S.; Brons, Jennifer A.; Figueiro, Mariana G.

2012-01-01

Epidemiological studies have shown an association between rotating shiftwork and breast cancer (BC) risk. Recently, light at night (LAN) measured by satellite photometry and by self-reports of bedroom brightness has been shown to be associated with BC risk, irrespective of shiftwork history. Importance has been placed on these associations because retinal light exposures at night can suppress the hormone melatonin and/or disrupt circadian entrainment to the local 24-h light-dark cycle. The present study examined whether it was valid to use satellite photometry and self-reports of brightness to characterize light, as it might stimulate the circadian system and thereby affect BC incidence. Calibrated photometric measurements were made at the bedroom windows and in the bedrooms of a sample of female school teachers, who worked regular dayshifts and lived in a variety of satellite-measured sky brightness categories. The light levels at both locations were usually very low and were independent of the amount of satellite-measured light. Calibrated photometric measurements were also obtained at the corneas of these female school teachers together with calibrated accelerometer measurements for seven consecutive days and evenings. Based upon these personal light exposure and activity measurements, the female teachers who participated in this study did not have disrupted light-dark cycles like those associated with rotating shiftworkers who do exhibit a higher risk for BC. Rather, this sample of female school teachers had 24-h light-dark and activity-rest patterns very much like those experienced by dayshift nurses examined in an earlier study who are not at an elevated risk of BC. No relationship was found between the amount of satellite-measured light levels and the 24-h light-dark patterns these women experienced. It was concluded from the present study that satellite photometry is unrelated to personal light exposures as they might affect melatonin suppression and

Dim light at night increases immune function in Nile grass rats, a diurnal rodent.

Science.gov (United States)

Fonken, Laura K; Haim, Achikam; Nelson, Randy J

2012-02-01

With the widespread adoption of electrical lighting during the 20th century, human and nonhuman animals became exposed to high levels of light at night for the first time in evolutionary history. This divergence from the natural environment may have significant implications for certain ecological niches because of the important influence light exerts on the circadian system. For example, circadian disruption and nighttime light exposure are linked to changes in immune function. The majority of studies investigating the effects of light exposure and circadian disruption on the immune system use nocturnal rodents. In diurnal species, many hormones and immune parameters vary with secretion patterns 180° out of phase to those of nocturnal rodents. Thus, the authors investigated the effects of nighttime light exposure on immunocompetence in diurnal Nile grass rats (Arvicanthis niloticus). Rats were housed in either standard 14-h light (L):10-h dark (D) cycles with L ∼150 lux and D 0 lux or dim light at night (dLAN) cycles of LD 14:10 with L ∼150 lux and D 5 lux for 3 wks, then tested for plasma bactericidal capacity, as well as humoral and cell-mediated immune responses. Rats exposed to dLAN showed increased delayed-type hypersensitivity pinna swelling, which is consistent with enhanced cell-mediated immune function. dLAN rats similarly showed increased antibody production following inoculation with keyhole lymphocyte hemocyanin (KLH) and increased bactericidal capacity. Daytime corticosterone concentrations were elevated in grass rats exposed to nighttime dim light, which may have influenced immunological measures. Overall, these results indicate nighttime light affects immune parameters in a diurnal rodent.

Mitochondrial damage and cytoskeleton reorganization in human dermal fibroblasts exposed to artificial visible light similar to screen-emitted light.

Science.gov (United States)

Rascalou, Adeline; Lamartine, Jérôme; Poydenot, Pauline; Demarne, Frédéric; Bechetoille, Nicolas

2018-05-05

Artificial visible light is everywhere in modern life. Social communication confronts us with screens of all kinds, and their use is on the rise. We are therefore increasingly exposed to artificial visible light, the effects of which on skin are poorly known. The purpose of this study was to model the artificial visible light emitted by electronic devices and assess its effect on normal human fibroblasts. The spectral irradiance emitted by electronic devices was optically measured and equipment was developed to accurately reproduce such artificial visible light. Effects on normal human fibroblasts were analyzed on human genome microarray-based gene expression analysis. At cellular level, visualization and image analysis were performed on the mitochondrial network and F-actin cytoskeleton. Cell proliferation, ATP release and type I procollagen secretion were also measured. We developed a device consisting of 36 LEDs simultaneously emitting blue, green and red light at distinct wavelengths (450 nm, 525 nm and 625 nm) with narrow spectra and equivalent radiant power for the three colors. A dose of 99 J/cm 2 artificial visible light was selected so as not to induce cell mortality following exposure. Microarray analysis revealed 2984 light-modulated transcripts. Functional annotation of light-responsive genes revealed several enriched functions including, amongst others, the "mitochondria" and "integrin signaling" categories. Selected results were confirmed by real-time quantitative PCR, analyzing 24 genes representing these two categories. Analysis of micro-patterned culture plates showed marked fragmentation of the mitochondrial network and disorganization of the F-actin cytoskeleton following exposure. Functionally, there was considerable impairment of cell growth and spread, ATP release and type I procollagen secretion in exposed fibroblasts. Artificial visible light induces drastic molecular and cellular changes in normal human fibroblasts. This may impede

Light pollution is associated with earlier tree budburst across the United Kingdom.

Science.gov (United States)

Ffrench-Constant, Richard H; Somers-Yeates, Robin; Bennie, Jonathan; Economou, Theodoros; Hodgson, David; Spalding, Adrian; McGregor, Peter K

2016-06-29

The ecological impact of night-time lighting is of concern because of its well-demonstrated effects on animal behaviour. However, the potential of light pollution to change plant phenology and its corresponding knock-on effects on associated herbivores are less clear. Here, we test if artificial lighting can advance the timing of budburst in trees. We took a UK-wide 13 year dataset of spatially referenced budburst data from four deciduous tree species and matched it with both satellite imagery of night-time lighting and average spring temperature. We find that budburst occurs up to 7.5 days earlier in brighter areas, with the relationship being more pronounced for later-budding species. Excluding large urban areas from the analysis showed an even more pronounced advance of budburst, confirming that the urban 'heat-island' effect is not the sole cause of earlier urban budburst. Similarly, the advance in budburst across all sites is too large to be explained by increases in temperature alone. This dramatic advance of budburst illustrates the need for further experimental investigation into the impact of artificial night-time lighting on plant phenology and subsequent species interactions. As light pollution is a growing global phenomenon, the findings of this study are likely to be applicable to a wide range of species interactions across the world. © 2016 The Authors.

The Consortium for Dark Sky Studies: A Transdisciplinary Institute for Understanding the Loss of the Night

Science.gov (United States)

Barentine, John; Kieda, David; Goldsmith, Stephen; Foott, Bettymaya; Muir, Janet

2018-01-01

Research into the effects of artificial light at night (ALAN) has grown from a niche speciality into a broad field touching on aspects of life science, physics, astronomy, social science, and more, reflecting the highly interconnected subjects whose common characteristic is the alteration of the natural nighttime environment by anthropogenic light pollution. Until recently, there was no focal point for these diverse efforts to foster connections between researchers and initiate new topics of study in ALAN research. In 2016, the Consortium for Dark Sky Studies (CDSS), the world’s first organization dedicated to the study of the night and the influence of human nighttime activities on the integrity of natural darkness, was founded at the University of Utah. We describe the motivations for establishing the Consortium, its early activities, and initial outcomes of the effort.

Poverty assessment using DMSP/OLS night-time light satellite imagery at a provincial scale in China

Science.gov (United States)

Wang, Wen; Cheng, Hui; Zhang, Li

2012-04-01

All countries around the world and many international bodies, including the United Nations Development Program (UNDP), United Nations Food and Agricultural Organization (FAO), the International Fund for Agricultural Development (IFAD) and the International Labor Organization (ILO), have to eliminate rural poverty. Estimation of regional poverty level is a key issue for making strategies to eradicate poverty. Most of previous studies on regional poverty evaluations are based on statistics collected typically in administrative units. This paper has discussed the deficiencies of traditional studies, and attempted to research regional poverty evaluation issues using 3-year DMSP/OLS night-time light satellite imagery. In this study, we adopted 17 socio-economic indexes to establish an integrated poverty index (IPI) using principal component analysis (PCA), which was proven to provide a good descriptor of poverty levels in 31 regions at a provincial scale in China. We also explored the relationship between DMSP/OLS night-time average light index and the poverty index using regression analysis in SPSS and a good positive linear correlation was modelled, with R2 equal to 0.854. We then looked at provincial poverty problems in China based on this correlation. The research results indicated that the DMSP/OLS night-time light data can assist analysing provincial poverty evaluation issues.

Teaching the Absorption of Light Colours Using an Artificial Rainbow

Science.gov (United States)

Yurumezoglu, Kemal; Isik, Hakan; Arikan, Gizem; Kabay, Gozde

2015-01-01

This paper presents an experimental activity based on the absorption of light colours by pigments. The activity is constructed using a stepwise design and offers an opportunity for students and teachers to compare and generalize the interactions between light and pigment colours. The light colours composing an artificial rainbow produced in the…

Parental Exposure to Dim Light at Night Prior to Mating Alters Offspring Adaptive Immunity

OpenAIRE

Ciss?, Yasmine M.; Russart, Kathryn L.G.; Nelson, Randy J.

2017-01-01

Exposure to dim light at night (dLAN) disrupts natural light/dark cycles and impairs endogenous circadian rhythms necessary to maintain optimal biological function, including the endocrine and immune systems. We have previously demonstrated that white dLAN compromises innate and cell mediated immune responses in adult Siberian hamsters (Phodopus sungorus). We hypothesized that dLAN has transgenerational influences on immune function. Adult male and female Siberian hamsters were exposed to eit...

Use of Circadian Lighting System to improve night shift alertness and performance of NRC Headquarters Operations Officers

International Nuclear Information System (INIS)

Baker, T.L.; Morisseau, D.; Murphy, N.M.

1995-01-01

The Nuclear Regulatory Commission's (NRC) Headquarters Operations Officers (HOOs) receive and respond to events reported in the nuclear industry on a 24-hour basis. The HOOs have reported reduced alertness on the night shift, leading to a potential deterioration in their on-shift cognitive performance during the early morning hours. For some HOOs, maladaptation to the night shift was also reported to be the principal cause of: (a) reduced alertness during the commute to and from work, (b) poor sleep quality, and (c) personal lifestyle problems. ShiftWork Systems, Inc. (SWS) designed and installed a Circadian Lighting System (CLS) at both the Bethesda and Rockville HOO stations with the goal of facilitating the HOOs physiological adjustment to their night shift schedules. The data indicate the following findings: less subjective fatigue on night shifts; improved night shift alertness and mental performance; higher HOO confidence in their ability to assess event reports; longer, deeper and more restorative day sleep after night duty shifts; swifter adaptation to night work; and a safer commute, particularly for those with extensive drives

Use of Circadian Lighting System to improve night shift alertness and performance of NRC Headquarters Operations Officers

Energy Technology Data Exchange (ETDEWEB)

Baker, T.L.; Morisseau, D.; Murphy, N.M. [ShiftWork Systems, Cambridge, MA (United States)] [and others

1995-04-01

The Nuclear Regulatory Commission`s (NRC) Headquarters Operations Officers (HOOs) receive and respond to events reported in the nuclear industry on a 24-hour basis. The HOOs have reported reduced alertness on the night shift, leading to a potential deterioration in their on-shift cognitive performance during the early morning hours. For some HOOs, maladaptation to the night shift was also reported to be the principal cause of: (a) reduced alertness during the commute to and from work, (b) poor sleep quality, and (c) personal lifestyle problems. ShiftWork Systems, Inc. (SWS) designed and installed a Circadian Lighting System (CLS) at both the Bethesda and Rockville HOO stations with the goal of facilitating the HOOs physiological adjustment to their night shift schedules. The data indicate the following findings: less subjective fatigue on night shifts; improved night shift alertness and mental performance; higher HOO confidence in their ability to assess event reports; longer, deeper and more restorative day sleep after night duty shifts; swifter adaptation to night work; and a safer commute, particularly for those with extensive drives.

The Value of Darkness: A Moral Framework for Urban Nighttime Lighting.

Science.gov (United States)

Stone, Taylor

2018-04-01

The adverse effects of artificial nighttime lighting, known as light pollution, are emerging as an important environmental issue. To address these effects, current scientific research focuses mainly on identifying what is bad or undesirable about certain types and uses of lighting at night. This paper adopts a value-sensitive approach, focusing instead on what is good about darkness at night. In doing so, it offers a first comprehensive analysis of the environmental value of darkness at night from within applied ethics. A design for values orientation is utilized to conceptualize, define, and categorize the ways in which value is derived from darkness. Nine values are identified and categorized via their type of good, temporal outlook, and spatial characteristics. Furthermore, these nine values are translated into prima facie moral obligations that should be incorporated into future design choices, policy-making, and innovations to nighttime lighting. Thus, the value of darkness is analyzed with the practical goal of informing future decision-making about urban nighttime lighting.

Bright-light effects on cognitive performance in elderly persons working simulated night shifts: psychological well-being as a mediator?

Science.gov (United States)

Kretschmer, Veronika; Schmidt, Klaus-Helmut; Griefahn, Barbara

2013-11-01

The present study examined whether the relationship between light exposure and cognitive functioning is mediated by psychological well-being in elderly persons working night shifts. The role of psychological well-being has been neglected so far in the relationship between bright light and cognitive performance. Sleepiness and mood were applied as indicators of psychological well-being. Cognitive functioning was examined in terms of concentration, working memory, and divided attention. A total of thirty-two test persons worked in three consecutive simulated night shifts, 16 under bright light (3,000 lux) and 16 under room light (300 lux). Concentration, working memory, and divided attention were measured by computerised tasks. The hypothesised mediators were recorded by questionnaires. Mediation analyses were conducted for estimating direct, total, and indirect effects in simple mediation models. Results indicate that sleepiness and mood did not function as mediators in the prediction of concentration, working memory, and/or divided attention by light exposure. Sleepiness led to an underestimation of the positive bright-light effect on concentration performance. Mood showed only a random effect due to the positive bright-light effect on working memory. Sleepiness and mood could completely be excluded as mediators in the relationship between light exposure and cognitive functioning. This study underlines that psychological well-being of elderly persons is not a critical component in the treatment of bright light on cognitive performance in the night shift workplace. In summary, it becomes evident that bright light has a strong direct and independent effect on cognitive performance, particularly on working memory and concentration.

The Effect of Differences in Day and Night Lighting Distributions on Drivers' Speed Perception.

Science.gov (United States)

Kim, Jonathan D; Perrone, John A; Isler, Robert B

2017-06-01

Previous research has shown that changes to contrast levels in the visual environment caused by fog can affect drivers' perceptions of speed. It is not easy, however, to extrapolate these results to other driving scenarios in which contrast is affected, such as during nighttime driving, because the measure of contrast is more complex when considering factors such as the illumination provided by headlights. Therefore, we investigated the differences in lighting distribution patterns between day- and nighttime driving on speed perception using prerendered 3D scenarios representing driving on a rural road. A two-alternative forced-choice design based on the method of constant stimuli was utilised, with 32 participants viewing a series of pairs of scenarios (day vs. night driving) from a driver's perspective while indicating for each pair whether the second scenario was faster or slower than the first scenario. Our results indicated that speed discrimination accuracy was minimally affected by changes in lighting distribution patterns between day and night.

Minimizing the Threat of Light Pollution on Observatories through Education: Globe at Night Citizen-Science

Science.gov (United States)

Walker, Constance E.; M, Pompea, Stephen

2018-01-01

Citizen-science is a rewardingly inclusive way to bring awareness to the public on the disappearance of the starry night sky, its cause and solutions. Globe at Night (GaN) encourages citizen-scientists worldwide to record the brightness of the night sky. During ten-days per month of moonless evenings, children and adults match the appearance of a specified constellation with 7 star maps of progressively fainter stars found at www.globeatnight.org. They then submit their choice of star map in-situ with the “webapp” by smart device to add to a light pollution map worldwide. In the eleven years of the program, over 170,000 observations from 180 countries have been contributed to the campaign.The Globe at Night (open) database is a source of research projects, even with other disciplines. For example, students conducted research to understand the lesser long-nosed bats’ avoidance of city center at night. On-the-fly mapping enables citizen-scientists to see contributed observations immediately. The 12 campaigns per year offer 4 ways of taking measurements. The online app for data submission is in 28 languages. STEM activities for young children and problem-based learning activities for older students were created to experience real-life scenarios: role-playing sea turtles hatching (misdirected by lights on shore) or analyzing an ISS image of Houston to estimate the wasted energy, cost and carbon footprint. In-situ and on-line workshops have been given on using GaN in all its capacities, as well as for the activities. Our Facebook page exists to encourage dialogue and bring cutting edge news. To entice interest, we had monthly newsletters and serial podcasts starring the Dark Skies Crusader. GaN has been part of special campaigns like with the National Park Service, the National Geographic BioBlitz and Tucson in 2011. Partnerships also include SciStarter (working with participants), Fieldscope (working with data analysis), and STARS4ALL (working with other light

Hybrid artificial photosynthetic systems comprising semiconductors as light harvesters and biomimetic complexes as molecular cocatalysts.

Science.gov (United States)

Wen, Fuyu; Li, Can

2013-11-19

Solar fuel production through artificial photosynthesis may be a key to generating abundant and clean energy, thus addressing the high energy needs of the world's expanding population. As the crucial components of photosynthesis, the artificial photosynthetic system should be composed of a light harvester (e.g., semiconductor or molecular dye), a reduction cocatalyst (e.g., hydrogenase mimic, noble metal), and an oxidation cocatalyst (e.g., photosystem II mimic for oxygen evolution from water oxidation). Solar fuel production catalyzed by an artificial photosynthetic system starts from the absorption of sunlight by the light harvester, where charge separation takes place, followed by a charge transfer to the reduction and oxidation cocatalysts, where redox reaction processes occur. One of the most challenging problems is to develop an artificial photosynthetic solar fuel production system that is both highly efficient and stable. The assembly of cocatalysts on the semiconductor (light harvester) not only can facilitate the charge separation, but also can lower the activation energy or overpotential for the reactions. An efficient light harvester loaded with suitable reduction and oxidation cocatalysts is the key for high efficiency of artificial photosynthetic systems. In this Account, we describe our strategy of hybrid photocatalysts using semiconductors as light harvesters with biomimetic complexes as molecular cocatalysts to construct efficient and stable artificial photosynthetic systems. We chose semiconductor nanoparticles as light harvesters because of their broad spectral absorption and relatively robust properties compared with a natural photosynthesis system. Using biomimetic complexes as cocatalysts can significantly facilitate charge separation via fast charge transfer from the semiconductor to the molecular cocatalysts and also catalyze the chemical reactions of solar fuel production. The hybrid photocatalysts supply us with a platform to study the

Measuring urban sprawl in China by night time light images

Science.gov (United States)

Liu, Lu; Tang, Lin

2017-01-01

In the process of urbanization, a phenomenon called “urban sprawl” usually occurs. This phenomenon may exaggerated the negative effects of urbanization on environment, public and social health, energy efficiency, and maintenance of farmland. Therefore, the understanding of this phenomenon is urgently required for us to achieve sustainable development. This study proposed a group of night time lights (NTL) indicators of urban sprawl, which intend to use the distribution of lightness to quantify urban sprawl. These measures are proved to be efficient in describing urban sprawl. In addition, they are consistent and easy calculating, making comparison analysis easy to be done. These indicators are used to study urban sprawl in China during the year 2000 to 2010, the results show that in the last ten years, metropolitan areas in the northern part of China have undergone a more sprawl-like urban growth compared with other parts of China.

Final Environmental Assessment for the Installation of a Range Safety Lighting System at Avon Park Air Force Range, Florida

Science.gov (United States)

2010-08-01

considered with other activities that require additional artificial night lighting. For instance, the development of the new town of Destiny planned...Mobarkey, M. Barak, A. Hoyzman, and O. Halevy, 2004. Monochromatic Light Stimuli During Embryogenesis Enhances Embryo Development and Posthatch

Measuring Light at Night and Melatonin Levels in Shift Workers: A Review of the Literature.

Science.gov (United States)

Hunter, Claudia M; Figueiro, Mariana G

2017-07-01

Shift work, especially that involving rotating and night shifts, is associated with an increased risk of diseases, including cancer. Attempts to explain the association between shift work and cancer in particular have focused on the processes of melatonin production and suppression. One hypothesis postulates that exposure to light at night (LAN) suppresses melatonin, whose production is known to slow the development of cancerous cells, while another proposes that circadian disruption associated with shift work, and not just LAN, increases health risks. This review focuses on six studies that employed quantitative measurement of LAN and melatonin levels to assess cancer risks in shift workers. These studies were identified via searching the PubMed database for peer-reviewed, English-language articles examining the links between shift work, LAN, and disease using the terms light at night, circadian disruption, health, risk, cancer, shift work, or rotating shift. While the results indicate a growing consensus on the relationship between disease risks (particularly cancer) and circadian disruption associated with shift work, the establishment of a direct link between LAN and disease has been impeded by contradictory studies and a lack of consistent, quantitative methods for measuring LAN in the research to date. Better protocols for assessing personal LAN exposure are required, particularly those employing calibrated devices that measure and sample exposure to workplace light conditions, to accurately assess LAN's effects on the circadian system and disease. Other methodologies, such as measuring circadian disruption and melatonin levels in the field, may also help to resolve discrepancies in the findings.

Stability of the nine sky quality meters in the Dutch night sky brightness monitoring network.

Science.gov (United States)

den Outer, Peter; Lolkema, Dorien; Haaima, Marty; van der Hoff, Rene; Spoelstra, Henk; Schmidt, Wim

2015-04-22

In the context of monitoring abundance of artificial light at night, the year-to-year stability of Sky Quality Meters (SQMs) is investigated by analysing intercalibrations derived from two measurement campaigns that were held in 2011 and 2012. An intercalibration comprises a light sensitivity factor and an offset for each SQM. The campaigns were concerned with monitoring measurements, each lasting one month. Nine SQMs, together forming the Night Sky Brightness Monitoring network (MHN) in The Netherlands, were involved in both campaigns. The stability of the intercalibration of these instruments leads to a year-to-year uncertainty (standard deviation) of 5% in the measured median luminance occurring at the MHN monitoring locations. For the 10-percentiles and 90-percentiles, we find 8% and 4%, respectively. This means that, for urban and industrial areas, changes in the sky brightness larger than 5% become detectable. Rural and nature areas require an 8%-9% change of the median luminance to be detectable. The light sensitivety agrees within 8% for the whole group of SQMs.

Acute dim light at night increases body mass, alters metabolism, and shifts core body temperature circadian rhythms.

Science.gov (United States)

Borniger, Jeremy C; Maurya, Santosh K; Periasamy, Muthu; Nelson, Randy J

2014-10-01

The circadian system is primarily entrained by the ambient light environment and is fundamentally linked to metabolism. Mounting evidence suggests a causal relationship among aberrant light exposure, shift work, and metabolic disease. Previous research has demonstrated deleterious metabolic phenotypes elicited by chronic (>4 weeks) exposure to dim light at night (DLAN) (∼ 5 lux). However, the metabolic effects of short-term (dim light would gain more body mass, alter whole body metabolism, and display altered body temperature (Tb) and activity rhythms compared to mice maintained in dark nights. Our data largely support these predictions; DLAN mice gained significantly more mass, reduced whole body energy expenditure, increased carbohydrate over fat oxidation, and altered temperature circadian rhythms. Importantly, these alterations occurred despite similar activity locomotor levels (and rhythms) and total food intake between groups. Peripheral clocks are potently entrained by body temperature rhythms, and the deregulation of body temperature we observed may contribute to metabolic problems due to "internal desynchrony" between the central circadian oscillator and temperature sensitive peripheral clocks. We conclude that even relatively short-term exposure to low levels of nighttime light can influence metabolism to increase mass gain.

Comparison between the Suomi-NPP Day-Night Band and DMSP-OLS for Correlating Socio-Economic Variables at the Provincial Level in China

Directory of Open Access Journals (Sweden)

Xin Jing

2015-12-01

stable data, and we artificially convert the pixel value of the DNB composite into six bits to match the DMSP stable data format. The correlation results between the processed data and socio-economic data show that the effects of saturation and quantization are two of the reasons for the correlation difference. Additionally, on this basis, we estimate the total night light ratio between saturation-corrected DMSP stable data and finite quantization DNB composite data, and it is found that the ratio is ~11.28 ± 4.02 for China. Therefore, it appears that a different acquisition time is the other reason for the correlation difference.

An Estimate of the Pixel-Level Connection between Visible Infrared Imaging Radiometer Suite Day/Night Band (VIIRS DNB Nighttime Lights and Land Features across China

Directory of Open Access Journals (Sweden)

Ting Ma

2018-05-01

Full Text Available Satellite-derived nighttime light images are increasingly used for various studies in relation to demographic, socioeconomic and urbanization dynamics because of the salient relationships between anthropogenic lighting signals at night and statistical variables at multiple scales. Owing to a higher spatial resolution and fewer over-glow and saturation effects, the new generation of nighttime light data derived from the Visible Infrared Imaging Radiometer Suite (VIIRS day/night band (DNB, which is located on board the Suomi National Polar-Orbiting Partnership (Suomi-NPP satellite, is expected to facilitate the performance of nocturnal luminosity-based investigations of human activity in a spatially explicit manner. In spite of the importance of the spatial connection between the VIIRS DNB nighttime light radiance (NTL and the land surface type at a fine scale, the crucial role of NTL-based investigations of human settlements is not well understood. In this study, we investigated the pixel-level relationship between the VIIRS DNB-derived NTL, a Landsat-derived land-use/land-cover dataset, and the map of point of interest (POI density over China, especially with respect to the identification of artificial surfaces in urban land. Our estimates suggest that notable differences in the NTL between urban (man-made surfaces and other types of land surfaces likely allow us to spatially identify most of the urban pixels with relatively high radiance values in VIIRS DNB images. Our results also suggest that current nighttime light data have a limited capability for detecting rural residential areas and explaining pixel-level variations in the POI density at a large scale. Moreover, the impact of non-man-made surfaces on the partitioned results appears inevitable because of the spatial heterogeneity of human settlements and the nature of remotely sensed nighttime light data. Using receiver operating characteristic (ROC curve-based analysis, we obtained

"Light-box" accelerated growth of poinsettias: LED-only illumination

Science.gov (United States)

Weerasuriya, Charitha; Detez, Stewart; Hock Ng, Soon; Hughes, Andrew; Callaway, Michael; Harrison, Iain; Katkus, Tomas; Juodkazis, Saulius

2018-01-01

For the current commercialized agricultural industry which requires a reduced product lead time to customer and supply all year round, an artificial light emitting diodes (LEDs)-based illumination has high potential due to high efficiency of electrical-to-light conversion. The main advantage of the deployed Red Green Blue Amber LED lighting system is colour mixing capability, which means ability to generate all the colours in the spectrum by using three or four primary colours LEDs. The accelerated plant growth was carried out in a "light-box" which was made to generate an artificial day/night cycle by moving the colour mixing ratio along the colour temperature curve of the chromaticity diagram. The control group of plants form the same initial batch was grown on the same shelf in a greenhouse at the same conditions with addition of artificial illumination by incandescent lamps for few hours. Costs and efficiency projections of LED lamps for horticultural applications is discussed together with required capital investment. The total cost of the "light-box" including LED lamps and electronics was 850 AUD.

Effects of Dim Light at Night on Food Intake and Body Mass in Developing Mice

OpenAIRE

Ciss?, Yasmine M.; Peng, Juan; Nelson, Randy J.

2017-01-01

Appropriately timed light is critical for circadian organization; exposure to dim light at night (dLAN) disrupts temporal organization of endogenous biological timing. Exposure to dLAN in adult mice is associated with elevated body mass and changes in metabolism putatively driven by voluntary changes in the time of food intake. We predicted that exposure of young mice to LAN could affect adult metabolic function. At 3 weeks (Experiment 1) or 5 weeks (Experiment 2) of age, mice were either mai...

Swimming black-crowned night-herons (Nycticorax nycticorax) Kleptoparasitize American coots (Fulica americana)

DEFF Research Database (Denmark)

Graves, Gary R.

2015-01-01

I observed black-crowned night-herons (Nycticorax nycticorax) swimming and kleptoparasitizing American coots (Fulica americana) at an artificial lake in Pinal County, Arizona. This appears to be the first record of interspecific kleptoparasitism by a swimming ardeid.......I observed black-crowned night-herons (Nycticorax nycticorax) swimming and kleptoparasitizing American coots (Fulica americana) at an artificial lake in Pinal County, Arizona. This appears to be the first record of interspecific kleptoparasitism by a swimming ardeid....

Activity patterns during food provisioning are affected by artificial light in free living great tits (Parus major.

Directory of Open Access Journals (Sweden)

Mieke Titulaer

Full Text Available Artificial light may have severe ecological consequences but there is limited experimental work to assess these consequences. We carried out an experimental study on a wild population of great tits (Parus major to assess the impact of light pollution on daily activity patterns during the chick provisioning period. Pairs that were provided with a small light outside their nest box did not alter the onset, cessation or duration of their working day. There was however a clear effect of artificial light on the feeding rate in the second half of the nestling period: when provided with artificial light females increased their feeding rate when the nestlings were between 9 and 16 days old. Artificial light is hypothesised to have affected the perceived photoperiod of either the parents or the offspring which in turn led to increased parental care. This may have negative fitness consequences for the parents, and light pollution may thus create an ecological trap for breeding birds.

Illumination properties and energy savings of a solar fiber optic lighting system balanced by artificial lights

OpenAIRE

Lingfors, David

2013-01-01

A solar fiber optic lighting system, SP3 from the Swedish company Parans Solar Lighting AB, has been installed in a study area/corridor test site. A collector is tracking the sun during daytime, focusing the direct sun irradiance via Fresnel lenses into optical fibers, which guide the solar light into the building. The illumination properties of the system have been characterized. The energy saving due to reduced need of artificial lighting have been calculated and methods for balancing the a...

Light pollution: Assessment of sky glow on two dark sky regions of Portugal.

Science.gov (United States)

Lima, Raul Cerveira; Pinto da Cunha, José; Peixinho, Nuno

2016-01-01

Artificial light at night (ALAN), producing light pollution (LP), is not a matter restricted to astronomy anymore. Light is part of modern societies and, as a consequence, the natural cycle day-night (bright-dark) has been interrupted in a large segment of the global population. There is increasing evidence that exposure to certain types of light at night and beyond threshold levels may produce hazardous effects to humans and the environment. The concept of "dark skies reserves" is a step forward in order to preserve the night sky and a means of enhancing public awareness of the problem of spread of light pollution worldwide. The aim of this study was to assess the skyglow at two sites in Portugal, the Peneda-Gerês National Park (PNPG) and the region now known as Dark Sky Alqueva Reserve. The latter site was classified as a "Starlight Tourism Destination" by the Starlight Foundation (the first in the world to achieve this classification) following a series of night sky measurements in situ described herein. The measurements at PNPG also contributed to the new set of regulations concerning light pollution at this national park. This study presents the first in situ systematic measurements of night sky brightness, showing that at the two sites the skies are mostly in levels 3 to 4 of the Bortle 9-level scale (with level 1 being the best achievable). The results indicate that the sources of light pollution and skyglow can be attributed predominantly to contamination from nearby urban regions.

The effect of blue-enriched white light on cognitive performances and sleepiness of night-shift workers: A field study.

Science.gov (United States)

Motamedzadeh, Majid; Golmohammadi, Rostam; Kazemi, Reza; Heidarimoghadam, Rashid

2017-08-01

Night-shift works are basically accompanied by reduced cognitive performance, sleepiness, and higher possibility for human error and related incidents. It is therefore crucial to improve individuals' performance and alertness in sensitive places like industries' control room with the ultimate goal of increasing efficiency and reducing the number of possible incidents. Previous research has indicated that blue light is a critical cue for entraining circadian rhythm. As a result, the present study was an attempt to investigate whether blue-enriched white light illumination was a practical strategy to decrease sleepiness and improve cognitive performance during night shifts. The study, which adopted a before-after interventional design, was conducted among 30 control room staff members of petrochemical industry. After baseline assessments under existing lighting conditions, every participant was exposed to two new lighting conditions (namely, 17,000K and 6500K blue-enriched white light), each lasting for a week. Assessments were conducted again at the end of these treatments. In order to measure the subjective sleepiness, Karolinska Sleepiness Scale (KSS) was utilized. Subjects also performed the Conners' Continuous Performance Test II (CPT-II) and 1-back test in order to gauge their cognitive performance, and melatonin assessment was carried out using salivary and Eliza technique. The data was analyzed using two-way repeated measure ANOVA. The results indicated that, compared to normal lighting conditions, participants' sleepiness and melatonin rhythm significantly declined when they were exposed to blue-enriched white light. Furthermore, the experimental condition had a significant effect on the reduction of working memory errors. It also decreased omission errors and the reaction time during the sustained attention task. Thus, using blue-enriched white light may be a proper ergonomic strategy for improving performance and alertness, especially during night, in

Phototaxis and polarotaxis hand in hand: night dispersal flight of aquatic insects distracted synergistically by light intensity and reflection polarization

Science.gov (United States)

Boda, Pál; Horváth, Gábor; Kriska, György; Blahó, Miklós; Csabai, Zoltán

2014-05-01

Based on an earlier observation in the field, we hypothesized that light intensity and horizontally polarized reflected light may strongly influence the flight behaviour of night-active aquatic insects. We assumed that phototaxis and polarotaxis together have a more harmful effect on the dispersal flight of these insects than they would have separately. We tested this hypothesis in a multiple-choice field experiment using horizontal test surfaces laid on the ground. We offered simultaneously the following visual stimuli for aerial aquatic insects: (1) lamplit matte black canvas inducing phototaxis alone, (2) unlit shiny black plastic sheet eliciting polarotaxis alone, (3) lamplit shiny black plastic sheet inducing simultaneously phototaxis and polarotaxis, and (4) unlit matte black canvas as a visually unattractive control. The unlit matte black canvas trapped only a negligible number (13) of water insects. The sum (16,432) of the total numbers of water beetles and bugs captured on the lamplit matte black canvas (7,922) and the unlit shiny black plastic sheet (8,510) was much smaller than the total catch (29,682) caught on the lamplit shiny black plastic sheet. This provides experimental evidence for the synergistic interaction of phototaxis (elicited by the unpolarized direct lamplight) and polarotaxis (induced by the strongly and horizontally polarized plastic-reflected light) in the investigated aquatic insects. Thus, horizontally polarizing artificial lamplit surfaces can function as an effective ecological trap due to this synergism of optical cues, especially in the urban environment.

Self-reported Impacts of LED Lighting Technology Compared to Fuel-based Lighting on Night Market Business Prosperity in Kenya

Energy Technology Data Exchange (ETDEWEB)

Johnstone, Peter; Jacobson, Arne; Mills, Evan; Mumbi, Maina

2009-02-11

The notion of"productive use" is often invoked in discussions about whether new technologies improve productivity or otherwise enhance commerce in developing-country contexts. It an elusive concept,especially when quantitative measures are sought. Improved and more energy efficient illumination systems for off-gridapplication--the focus of the Lumina Project--provide a case in which a significant productivity benefit can be imagined, given the importance of light to the successful performance of many tasks, and the very low quality of baseline illumination provided by flame-based source. This Research Note summarizes self-reported quantitative and qualitative impacts of switching to LED lighting technology on the prosperity of night-market business owners and operators. The information was gathered in the context of our 2008 market testing field work in Kenya?s Rift Valley Province, which was performed in the towns of Maai Mahiu and Karagita by Arne Jacobson, Kristen Radecsky, Peter Johnstone, Maina Mumbi, and others. Maai Mahiu is a crossroads town; provision of services to travelers and freight carriers is a primary income source for the residents. In contrast, the primary income for Karagita's residents is from work in the large, factory style flower farms on the eastern shores of Lake Naivasha that specialize in producing cut flowers for export to the European market. According to residents, both towns had populations of 6,000 to 8,000 people in June 2008. We focused on quantifying the economics of fuel-based and LED lighting technology in the context of business use by night market vendors and shop keepers. Our research activities with the business owners and operators included baseline measurement of their fuel-based lighting use, an initial survey, offering for sale data logger equipped rechargeable LED lamps, monitoring the adoption of the LED lamps, and a follow-up survey.

Rotating night shift work, sleep quality, selected lifestyle factors and prolactin concentration in nurses and midwives.

Science.gov (United States)

Bukowska, Agnieszka; Sobala, Wojciech; Peplonska, Beata

2015-04-01

The pattern of secretion of many hormones, including prolactin, is dependent on the circadian rhythm. Night shift work involves exposure to artificial light at night and sleep deficiency, which in turn can affect prolactin synthesis. The aim of this study was to evaluate a possible association between night shift work characteristics, sleep quality, lifestyle factors and prolactin concentration, using data from a cross-sectional study of nurses and midwives. A cross-sectional study was conducted among 327 nurses and midwives currently working on rotating night shifts, and 330 nurses and midwives working during the day (aged 40-60 years) (388 premenopausal and 269 postmenopausal). Information about night shift work characteristics, lifestyle, reproductive factors, sleep pattern and other covariates was collected through a face-to-face interview, and from a one-week work and sleep diary completed by the subjects. Weight and height were measured. Prolactin concentration was measured in the morning blood sample using the electrochemiluminesence immunoassay method. Associations were analyzed using linear regression models adjusted for important confounders. Analyses were carried out separately in pre- and postmenopausal women. None of the night shift work or sleep characteristics was significantly associated with prolactin concentration. Prolactin concentration was significantly (p night shift work is not associated with prolactin concentration. Smoking, parity, time of blood collection and age among postmenopausal women were significant determinants of prolactin.

Melatonin the "light of night" in human biology and adolescent idiopathic scoliosis

Directory of Open Access Journals (Sweden)

Savvidou Olga D

2007-04-01

Full Text Available Abstract Melatonin "the light of night" is secreted from the pineal gland principally at night. The hormone is involved in sleep regulation, as well as in a number of other cyclical bodily activities and circadian rhythm in humans. Melatonin is exclusively involved in signalling the 'time of day' and 'time of year' (hence considered to help both clock and calendar functions to all tissues and is thus considered to be the body's chronological pacemaker or 'Zeitgeber'. The last decades melatonin has been used as a therapeutic chemical in a large spectrum of diseases, mainly in sleep disturbances and tumours and may play a role in the biologic regulation of mood, affective disorders, cardiovascular system, reproduction and aging. There are few papers regarding melatonin and its role in adolescent idiopathic scoliosis (AIS. Melatonin may play a role in the pathogenesis of scoliosis (neuroendocrine hypothesis but at present, the data available cannot clearly support this hypothesis. Uncertainties and doubts still surround the role of melatonin in human physiology and pathophysiology and future research is needed.

Evaluating an emergent behaviour algorithm in JCSP for energy conservation in lighting systems

DEFF Research Database (Denmark)

Kosek, Anna Magdalena; Syed, Aly; Kerridge, J.

2011-01-01

Since the invention of the light bulb, artificial light is accompanying people all around the world every day and night. As the light bulb itself evolved a lot through years, light control systems are still switch-based and require users to make most of the decisions about its behaviour. This pap...... presents an algorithm for emergent behaviour in a lighting system to achieve stable, user defined light level, while saving energy. The algorithm employs a parallel design and was tested using JCSP. © 2011 The authors and IOS Press. All rights reserved....

Levels of daily light doses under changed day-night cycles regulate temporal segregation of photosynthesis and N2 Fixation in the cyanobacterium Trichodesmium erythraeum IMS101.

Science.gov (United States)

Cai, Xiaoni; Gao, Kunshan

2015-01-01

While the diazotrophic cyanobacterium Trichodesmium is known to display inverse diurnal performances of photosynthesis and N2 fixation, such a phenomenon has not been well documented under different day-night (L-D) cycles and different levels of light dose exposed to the cells. Here, we show differences in growth, N2 fixation and photosynthetic carbon fixation as well as photochemical performances of Trichodesmium IMS101 grown under 12L:12D, 8L:16D and 16L:8D L-D cycles at 70 μmol photons m-2 s-1 PAR (LL) and 350 μmol photons m-2 s-1 PAR (HL). The specific growth rate was the highest under LL and the lowest under HL under 16L:8D, and it increased under LL and decreased under HL with increased levels of daytime light doses exposed under the different light regimes, respectively. N2 fixation and photosynthetic carbon fixation were affected differentially by changes in the day-night regimes, with the former increasing directly under LL with increased daytime light doses and decreased under HL over growth-saturating light levels. Temporal segregation of N2 fixation from photosynthetic carbon fixation was evidenced under all day-night regimes, showing a time lag between the peak in N2 fixation and dip in carbon fixation. Elongation of light period led to higher N2 fixation rate under LL than under HL, while shortening the light exposure to 8 h delayed the N2 fixation peaking time (at the end of light period) and extended it to night period. Photosynthetic carbon fixation rates and transfer of light photons were always higher under HL than LL, regardless of the day-night cycles. Conclusively, diel performance of N2 fixation possesses functional plasticity, which was regulated by levels of light energy supplies either via changing light levels or length of light exposure.

Effects of Dim Light at Night on Food Intake and Body Mass in Developing Mice.

Science.gov (United States)

Cissé, Yasmine M; Peng, Juan; Nelson, Randy J

2017-01-01

Appropriately timed light is critical for circadian organization; exposure to dim light at night (dLAN) disrupts temporal organization of endogenous biological timing. Exposure to dLAN in adult mice is associated with elevated body mass and changes in metabolism putatively driven by voluntary changes in the time of food intake. We predicted that exposure of young mice to LAN could affect adult metabolic function. At 3 weeks (Experiment 1) or 5 weeks (Experiment 2) of age, mice were either maintained in standard light-dark (DARK) cycles or exposed to nightly dLAN (5 lux). In the first two experiments, food intake and locomotor activity were assessed after 4 weeks and a glucose tolerance test was administered after 6 weeks in experimental lighting conditions. In Experiment 3, tissues were collected around the clock at 6 h intervals to investigate rhythmic hepatic clock gene expression in mice exposed to dLAN from 3 or 5 weeks of age. Male and female mice exposed to dLAN beginning at 3 weeks of age displayed similar growth rates and body mass to DARK-reared offspring, despite increasing day-time food intake. Exposure to dLAN beginning at 5 weeks of age increased body mass and daytime food intake in male, but not female, mice. Consistent with the body mass phenotype, clock gene expression was unaltered in the liver. In contrast to adults, dLAN exposure during the development of the peripheral circadian system has sex- and development-dependent effects on body mass gain.

Effects of Dim Light at Night on Food Intake and Body Mass in Developing Mice

Directory of Open Access Journals (Sweden)

Yasmine M. Cissé

2017-05-01

Full Text Available Appropriately timed light is critical for circadian organization; exposure to dim light at night (dLAN disrupts temporal organization of endogenous biological timing. Exposure to dLAN in adult mice is associated with elevated body mass and changes in metabolism putatively driven by voluntary changes in the time of food intake. We predicted that exposure of young mice to LAN could affect adult metabolic function. At 3 weeks (Experiment 1 or 5 weeks (Experiment 2 of age, mice were either maintained in standard light-dark (DARK cycles or exposed to nightly dLAN (5 lux. In the first two experiments, food intake and locomotor activity were assessed after 4 weeks and a glucose tolerance test was administered after 6 weeks in experimental lighting conditions. In Experiment 3, tissues were collected around the clock at 6 h intervals to investigate rhythmic hepatic clock gene expression in mice exposed to dLAN from 3 or 5 weeks of age. Male and female mice exposed to dLAN beginning at 3 weeks of age displayed similar growth rates and body mass to DARK-reared offspring, despite increasing day-time food intake. Exposure to dLAN beginning at 5 weeks of age increased body mass and daytime food intake in male, but not female, mice. Consistent with the body mass phenotype, clock gene expression was unaltered in the liver. In contrast to adults, dLAN exposure during the development of the peripheral circadian system has sex- and development-dependent effects on body mass gain.

The influence of day/night cycles on biomass yield and composition of Neochloris oleoabundans.

Science.gov (United States)

de Winter, Lenneke; Cabanelas, Iago Teles Dominguez; Martens, Dirk E; Wijffels, René H; Barbosa, Maria J

2017-01-01

Day/night cycles regulate the circadian clock of organisms to program daily activities. Many species of microalgae have a synchronized cell division when grown under a day/night cycle, and synchronization might influence biomass yield and composition. Therefore, the aim of this study was to study the influence of day/night cycle on biomass yield and composition of the green microalgae Neochloris oleoabundans . Hence, we compared continuous turbidostat cultures grown under continuous light with cultures grown under simulated day/night cycles. Under day/night cycles, cultures were synchronized as cell division was scheduled in the night, whereas under continuous light cell division occurred randomly synchronized cultures were able to use the light 10-15% more efficiently than non-synchronized cultures. Our results indicate that the efficiency of light use varies over the cell cycle and that synchronized cell division provides a fitness benefit to microalgae. Biomass composition under day/night cycles was similar to continuous light, with the exception of starch content. The starch content was higher in cultures under continuous light, most likely because the cells never had to respire starch to cover for maintenance during dark periods. Day/night cycles were provided in a 'block' (continuous light intensity during the light period) and in a 'sine' (using a sine function to simulate light intensities from sunrise to sunset). There were no differences in biomass yield or composition between these two ways of providing light (in a 'block' or in a 'sine'). The biomass yield and composition of N. oleoabundans were influenced by day/night cycles. These results are important to better understand the relations between research done under continuous light conditions and with day/night cycle conditions. Our findings also imply that more research should be done under day/night cycles.

EVENT DETECTION USING MOBILE PHONE MASS GPS DATA AND THEIR RELIAVILITY VERIFICATION BY DMSP/OLS NIGHT LIGHT IMAGE

Directory of Open Access Journals (Sweden)

A. Yuki

2016-06-01

Full Text Available In this study, we developed a method to detect sudden population concentration on a certain day and area, that is, an “Event,” all over Japan in 2012 using mass GPS data provided from mobile phone users. First, stay locations of all phone users were detected using existing methods. Second, areas and days where Events occurred were detected by aggregation of mass stay locations into 1-km-square grid polygons. Finally, the proposed method could detect Events with an especially large number of visitors in the year by removing the influences of Events that occurred continuously throughout the year. In addition, we demonstrated reasonable reliability of the proposed Event detection method by comparing the results of Event detection with light intensities obtained from the night light images from the DMSP/OLS night light images. Our method can detect not only positive events such as festivals but also negative events such as natural disasters and road accidents. These results are expected to support policy development of urban planning, disaster prevention, and transportation management.

Induction of cellular transformation by irradiation from artificial light sources

International Nuclear Information System (INIS)

Withrow, T.J.

1981-01-01

Cellular transformation in vitro has been used to test for the carcinogenic potential of chemical and physical insults including light. This report discusses the measurement of transformation, and reviews studies done on the effects of exposure to artificial light on cellular transformation or on cellular transformation by a virus. To date, cool-white lamps have been found to cause cellular transformation, while germicidal lamps and sunlamps have been found to cause cellular transformation and to enhance virally produced transformation

Does light pollution alter daylength? A test using light loggers on free-ranging European blackbirds (Turdus merula).

Science.gov (United States)

Dominoni, Davide M; Partecke, Jesko

2015-05-05

Artificial light at night is one of the most apparent environmental changes accompanying anthropogenic habitat change. The global increase in light pollution poses new challenges to wild species, but we still have limited understanding of the temporal and spatial pattern of exposure to light at night. In particular, it has been suggested by several studies that animals exposed to light pollution, such as songbirds, perceive a longer daylength compared with conspecifics living in natural darker areas, but direct tests of such a hypothesis are still lacking. Here, we use a combination of light loggers deployed on individual European blackbirds, as well as automated radio-telemetry, to examine whether urban birds are exposed to a longer daylength than forest counterparts. We first used activity data from forest birds to determine the level of light intensity which defines the onset and offset of daily activity in rural areas. We then used this value as threshold to calculate the subjective perceived daylength of both forest and urban blackbirds. In March, when reproductive growth occurs, urban birds were exposed on average to a 49-min longer subjective perceived daylength than forest ones, which corresponds to a 19-day difference in photoperiod at this time of the year. In the field, urban blackbirds reached reproductive maturity 19 day earlier than rural birds, suggesting that light pollution could be responsible of most of the variation in reproductive timing found between urban and rural dwellers. We conclude that light at night is the most relevant change in ambient light affecting biological rhythms in avian urban-dwellers, most likely via a modification of the perceived photoperiod. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Night Vision Image De-Noising of Apple Harvesting Robots Based on the Wavelet Fuzzy Threshold

Directory of Open Access Journals (Sweden)

Chengzhi Ruan

2015-12-01

Full Text Available In this paper, the de-noising problem of night vision images is studied for apple harvesting robots working at night. The wavelet threshold method is applied to the de-noising of night vision images. Due to the fact that the choice of wavelet threshold function restricts the effect of the wavelet threshold method, the fuzzy theory is introduced to construct the fuzzy threshold function. We then propose the de-noising algorithm based on the wavelet fuzzy threshold. This new method can reduce image noise interferences, which is conducive to further image segmentation and recognition. To demonstrate the performance of the proposed method, we conducted simulation experiments and compared the median filtering and the wavelet soft threshold de-noising methods. It is shown that this new method can achieve the highest relative PSNR. Compared with the original images, the median filtering de-noising method and the classical wavelet threshold de-noising method, the relative PSNR increases 24.86%, 13.95%, and 11.38% respectively. We carry out comparisons from various aspects, such as intuitive visual evaluation, objective data evaluation, edge evaluation and artificial light evaluation. The experimental results show that the proposed method has unique advantages for the de-noising of night vision images, which lay the foundation for apple harvesting robots working at night.

Overnight Glucose Control with Dual- and Single-Hormone Artificial Pancreas in Type 1 Diabetes with Hypoglycemia Unawareness: A Randomized Controlled Trial.

Science.gov (United States)

Abitbol, Alexander; Rabasa-Lhoret, Remi; Messier, Virginie; Legault, Laurent; Smaoui, Mohamad; Cohen, Nathan; Haidar, Ahmad

2018-03-01

The dual-hormone (insulin and glucagon) artificial pancreas may be justifiable in some, but not all, patients. We sought to compare dual- and single-hormone artificial pancreas systems in patients with hypoglycemia unawareness and documented nocturnal hypoglycemia. We conducted a randomized crossover trial comparing the efficacy of dual- and single-hormone artificial pancreas systems in controlling plasma glucose levels over the course of one night's sleep. We recruited 18 adult participants with hypoglycemia unawareness and 17 participants with hypoglycemia awareness, all of whom had documented nocturnal hypoglycemia during 2 weeks of screening. Outcomes were calculated using plasma glucose. In participants with hypoglycemia unawareness, the median (interquartile range [IQR]) percentage of time that plasma glucose was below 4.0 mmol/L was 0% (0-0) on dual-hormone artificial pancreas nights and 0% (0-10) on single-hormone artificial pancreas nights (P = 0.20). Additionally, participants with hypoglycemia unawareness experienced two hypoglycemic events (dual-hormone artificial pancreas nights and three hypoglycemic events on single-hormone artificial pancreas nights. In participants with hypoglycemia awareness, the median (IQR) percentage of time that plasma glucose was below 4.0 mmol/L was 0% (0-0) on both dual- and single-hormone artificial pancreas nights. Hypoglycemia awareness participants experienced zero hypoglycemic events on dual-hormone artificial pancreas nights and one event on single-hormone artificial pancreas nights. In this study, dual-hormone and single-hormone systems performed equally well in preventing nocturnal hypoglycemia in participants with hypoglycemia unawareness. Longer studies over the course of multiple days and nights may be needed to explore possible specific benefits in this population. ClinicalTrials.gov No. NCT02282254.

Rapid resetting of human peripheral clocks by phototherapy during simulated night shift work.

Science.gov (United States)

Cuesta, Marc; Boudreau, Philippe; Cermakian, Nicolas; Boivin, Diane B

2017-11-24

A majority of night shift workers have their circadian rhythms misaligned to their atypical schedule. While bright light exposure at night is known to reset the human central circadian clock, the behavior of peripheral clocks under conditions of shift work is more elusive. The aim of the present study was to quantify the resetting effects of bright light exposure on both central (plasma cortisol and melatonin) and peripheral clocks markers (clock gene expression in peripheral blood mononuclear cells, PBMCs) in subjects living at night. Eighteen healthy subjects were enrolled to either a control (dim light) or a bright light group. Blood was sampled at baseline and on the 4 th day of simulated night shift. In response to a night-oriented schedule, the phase of PER1 and BMAL1 rhythms in PBMCs was delayed by ~2.5-3 h (P shift was observed for the other clock genes and the central markers. Three cycles of 8-h bright light induced significant phase delays (P night-oriented schedule and a rapid resetting effect of nocturnal bright light exposure on peripheral clocks.

Light-Triggered Soft Artificial Muscles: Molecular-Level Amplification of Actuation Control Signals.

Science.gov (United States)

Dicker, Michael P M; Baker, Anna B; Iredale, Robert J; Naficy, Sina; Bond, Ian P; Faul, Charl F J; Rossiter, Jonathan M; Spinks, Geoffrey M; Weaver, Paul M

2017-08-23

The principle of control signal amplification is found in all actuation systems, from engineered devices through to the operation of biological muscles. However, current engineering approaches require the use of hard and bulky external switches or valves, incompatible with both the properties of emerging soft artificial muscle technology and those of the bioinspired robotic systems they enable. To address this deficiency a biomimetic molecular-level approach is developed that employs light, with its excellent spatial and temporal control properties, to actuate soft, pH-responsive hydrogel artificial muscles. Although this actuation is triggered by light, it is largely powered by the resulting excitation and runaway chemical reaction of a light-sensitive acid autocatalytic solution in which the actuator is immersed. This process produces actuation strains of up to 45% and a three-fold chemical amplification of the controlling light-trigger, realising a new strategy for the creation of highly functional soft actuating systems.

A Red-Light Running Prevention System Based on Artificial Neural Network and Vehicle Trajectory Data

Directory of Open Access Journals (Sweden)

Pengfei Li

2014-01-01

Full Text Available The high frequency of red-light running and complex driving behaviors at the yellow onset at intersections cannot be explained solely by the dilemma zone and vehicle kinematics. In this paper, the author presented a red-light running prevention system which was based on artificial neural networks (ANNs to approximate the complex driver behaviors during yellow and all-red clearance and serve as the basis of an innovative red-light running prevention system. The artificial neural network and vehicle trajectory are applied to identify the potential red-light runners. The ANN training time was also acceptable and its predicting accurate rate was over 80%. Lastly, a prototype red-light running prevention system with the trained ANN model was described. This new system can be directly retrofitted into the existing traffic signal systems.

A red-light running prevention system based on artificial neural network and vehicle trajectory data.

Science.gov (United States)

Li, Pengfei; Li, Yan; Guo, Xiucheng

2014-01-01

The high frequency of red-light running and complex driving behaviors at the yellow onset at intersections cannot be explained solely by the dilemma zone and vehicle kinematics. In this paper, the author presented a red-light running prevention system which was based on artificial neural networks (ANNs) to approximate the complex driver behaviors during yellow and all-red clearance and serve as the basis of an innovative red-light running prevention system. The artificial neural network and vehicle trajectory are applied to identify the potential red-light runners. The ANN training time was also acceptable and its predicting accurate rate was over 80%. Lastly, a prototype red-light running prevention system with the trained ANN model was described. This new system can be directly retrofitted into the existing traffic signal systems.

A Red-Light Running Prevention System Based on Artificial Neural Network and Vehicle Trajectory Data

Science.gov (United States)

Li, Pengfei; Li, Yan; Guo, Xiucheng

2014-01-01

The high frequency of red-light running and complex driving behaviors at the yellow onset at intersections cannot be explained solely by the dilemma zone and vehicle kinematics. In this paper, the author presented a red-light running prevention system which was based on artificial neural networks (ANNs) to approximate the complex driver behaviors during yellow and all-red clearance and serve as the basis of an innovative red-light running prevention system. The artificial neural network and vehicle trajectory are applied to identify the potential red-light runners. The ANN training time was also acceptable and its predicting accurate rate was over 80%. Lastly, a prototype red-light running prevention system with the trained ANN model was described. This new system can be directly retrofitted into the existing traffic signal systems. PMID:25435870

Chronic dim light at night provokes reversible depression-like phenotype: possible role for TNF.

Science.gov (United States)

Bedrosian, T A; Weil, Z M; Nelson, R J

2013-08-01

The prevalence of major depression has increased in recent decades and women are twice as likely as men to develop the disorder. Recent environmental changes almost certainly have a role in this phenomenon, but a complete set of contributors remains unspecified. Exposure to artificial light at night (LAN) has surged in prevalence during the past 50 years, coinciding with rising rates of depression. Chronic exposure to LAN is linked to increased risk of breast cancer, obesity and mood disorders, although the relationship to mood is not well characterized. In this study, we investigated the effects of chronic exposure to 5 lux LAN on depression-like behaviors in female hamsters. Using this model, we also characterized hippocampal brain-derived neurotrophic factor expression and hippocampal dendritic morphology, and investigated the reversibility of these changes 1, 2 or 4 weeks following elimination of LAN. Furthermore, we explored the mechanism of action, focusing on hippocampal proinflammatory cytokines given their dual role in synaptic plasticity and the pathogenesis of depression. Using reverse transcription-quantitative PCR, we identified a reversible increase in hippocampal tumor necrosis factor (TNF), but not interleukin-1β, mRNA expression in hamsters exposed to LAN. Direct intracerebroventricular infusion of a dominant-negative inhibitor of soluble TNF, XPro1595, prevented the development of depression-like behavior under LAN, but had no effect on dendritic spine density in the hippocampus. These results indicate a partial role for TNF in the reversible depression-like phenotype observed under chronic dim LAN. Recent environmental changes, such as LAN exposure, may warrant more attention as possible contributors to rising rates of mood disorders.

A night with good vibrations

CERN Multimedia

2002-01-01

For its third edition, the Museum d'histoire des sciences invites you to a Science Night under the banner of waves and undulations. Scientists, artists and storytellers from more than forty institutes and local or regional associations will show in only one weekend that waves and undulations form an integral part of our daily environment. Telephones, televisions, radios, irons, lighting, music, sun rays, stars, rainbows, earthquakes and other natural phenomena - all produce, emit or receive waves or undulations. The visitors attending the Night will be able to get in contact with the nature of waves through interactive exhibitions on sound and light and through hands-on demonstrations arranged around the Bartholoni villa and in the Park of the Perle du lac. An amusing and distracting way to familiarize yourself with the concepts of wavelength, frequency and interference lengths... In addition to the stands, the Night will offer many other activities: reconstructions of critical experiments, scientific consu...

A night with good vibrations

CERN Multimedia

2002-01-01

Next week-end, the Geneva Science History Museum invites you to a Science Night under the banner of waves and vibrations. Scientists, artists and storytellers from more than forty institutes and local or regional associations will show that waves and vibrations form an integral part of our environment. You will be able to get in contact with the nature of waves through interactive exhibitions on sound and light and through hands-on demonstrations arranged in the Park of the Perle du Lac. On the CERN stand, you will be able to measure the speed of light with a bar of chocolate, and understand the scattering of waves with plastic ducks. Amazing, no? In addition to the stands, the Night will offer many other activities: reconstructions of experiments, a play, a concert of crystal glasses, an illuminated fountain, a house of spirits. More information Science Night, 6 and 7 July, Park of the Perle du Lac, Geneva

Multi-channel automotive night vision system

Science.gov (United States)

Lu, Gang; Wang, Li-jun; Zhang, Yi

2013-09-01

A four-channel automotive night vision system is designed and developed .It is consist of the four active near-infrared cameras and an Mulit-channel image processing display unit,cameras were placed in the automobile front, left, right and rear of the system .The system uses near-infrared laser light source，the laser light beam is collimated, the light source contains a thermoelectric cooler (TEC),It can be synchronized with the camera focusing, also has an automatic light intensity adjustment, and thus can ensure the image quality. The principle of composition of the system is description in detail,on this basis, beam collimation,the LD driving and LD temperature control of near-infrared laser light source,four-channel image processing display are discussed.The system can be used in driver assistance, car BLIS, car parking assist system and car alarm system in day and night.

Green lights

DEFF Research Database (Denmark)

Fisker, Peter Kielberg

This study investigates the effect of drought on economic activity globally using remote sensing data. In particular, predicted variation in greenness is correlated with changes in the density of artificial light observed at night on a grid of 0.25 degree latitude-longitude pixels. I define drought...... as greenness estimated by lagged variation in monthly rainfall and temperature. This definition of drought performs well in identifying self-reported drought events since 2000 compared with measures of drought that do not take greenness into account, and the subsequent analysis indicates that predicted...... variation in greenness is positively associated with year-on-year changes in luminosity: If a unit of observation experiences a predicted variation in greenness that lies 1 standard deviation below the global mean, on average 1.5 - 2.5 light pixels out of 900 are extinguished that year. Finally, an attempt...

Influence of artificially induced light pollution on the hormone system of two common fish species, perch and roach, in a rural habitat.

Science.gov (United States)

Brüning, Anika; Kloas, Werner; Preuer, Torsten; Hölker, Franz

2018-01-01

Almost all life on earth has adapted to natural cycles of light and dark by evolving circadian and circannual rhythms to synchronize behavioural and physiological processes with the environment. Artificial light at night (ALAN) is suspected to interfere with these rhythms. In this study we examined the influence of ALAN on nocturnal melatonin and sex steroid blood concentrations and mRNA expression of gonadotropins in the pituitary of European perch ( Perca fluviatilis ) and roach ( Rutilus rutilus ). In a rural experimental setting, fish were held in net cages in drainage channels experiencing either additional ALAN of ~15 lx at the water surface or natural light conditions at half-moon. No differences in melatonin concentrations between ALAN and natural conditions were detected. However, blood concentration of sex steroids (17β-estradiol; 11-ketotestosterone) as well as mRNA expression of gonadotropins (luteinizing hormone, follicle stimulating hormone) was reduced in both fish species. We conclude that ALAN can disturb biological rhythms in fish in urban waters. However, impacts on melatonin rhythm might have been blurred by individual differences, sampling methods and moonlight. The effect of ALAN on biomarkers of reproduction suggests a photo-labile period around the onset of gonadogenesis, including the experimental period (August). Light pollution therefore has a great potential to influence crucial life history traits with unpredictable outcome for fish population dynamics.

Bright lights, big city: influences of ecological light pollution on reciprocal stream-riparian invertebrate fluxes.

Science.gov (United States)

Meyer, Lars A; Sullivan, S Mazeika P

2013-09-01

Cities produce considerable ecological light pollution (ELP), yet the effects of artificial night lighting on biological communities and ecosystem function have not been fully explored. From June 2010 to June 2011, we surveyed aquatic emergent insects, riparian arthropods entering the water, and riparian spiders of the family Tetragnathidae at nine stream reaches representing common ambient ELP levels of Columbus, Ohio, USA, streams (low, 0.1-0.5 lux; moderate, 0.6-2.0 lux; high, 2.1-4.0 lux). In August 2011, we experimentally increased light levels at the low- and moderate-treatment reaches to 10-12 lux to represent urban streams exposed to extremely high levels of ELP. Although season exerted the dominant influence on invertebrate fluxes over the course of the year, when analyzed by season, we found that light strongly influenced multiple invertebrate responses. The experimental light addition resulted in a 44% decrease in tetragnathid spider density (P = 0.035), decreases of 16% in family richness (P = 0.040) and 76% in mean body size (P = 0.022) of aquatic emergent insects, and a 309% increase in mean body size of terrestrial arthropods (P = 0.015). Our results provide evidence that artificial light sources can alter community structure and ecosystem function in streams via changes in reciprocal aquatic-terrestrial fluxes of invertebrates.

Green Light for Nocturnally Migrating Birds

Directory of Open Access Journals (Sweden)

Hanneke Poot

2008-12-01

Laboratory experiments have shown the magnetic compass to be wavelength dependent: migratory birds require light from the blue-green part of the spectrum for magnetic compass orientation, whereas red light (visible long-wavelength disrupts magnetic orientation. We designed a field study to test if and how changing light color influenced migrating birds under field conditions. We found that nocturnally migrating birds were disoriented and attracted by red and white light (containing visible long-wavelength radiation, whereas they were clearly less disoriented by blue and green light (containing less or no visible long-wavelength radiation. This was especially the case on overcast nights. Our results clearly open perspective for the development of bird-friendly artificial lighting by manipulating wavelength characteristics. Preliminary results with an experimentally developed bird-friendly light source on an offshore platform are promising. What needs to be investigated is the impact of bird-friendly light on other organisms than birds.

Dim light at night disturbs the daily sleep-wake cycle in the rat.

Science.gov (United States)

Stenvers, Dirk Jan; van Dorp, Rick; Foppen, Ewout; Mendoza, Jorge; Opperhuizen, Anne-Loes; Fliers, Eric; Bisschop, Peter H; Meijer, Johanna H; Kalsbeek, Andries; Deboer, Tom

2016-10-20

Exposure to light at night (LAN) is associated with insomnia in humans. Light provides the main input to the master clock in the hypothalamic suprachiasmatic nucleus (SCN) that coordinates the sleep-wake cycle. We aimed to develop a rodent model for the effects of LAN on sleep. Therefore, we exposed male Wistar rats to either a 12 h light (150-200lux):12 h dark (LD) schedule or a 12 h light (150-200 lux):12 h dim white light (5 lux) (LDim) schedule. LDim acutely decreased the amplitude of daily rhythms of REM and NREM sleep, with a further decrease over the following days. LDim diminished the rhythms of 1) the circadian 16-19 Hz frequency domain within the NREM sleep EEG, and 2) SCN clock gene expression. LDim also induced internal desynchronization in locomotor activity by introducing a free running rhythm with a period of ~25 h next to the entrained 24 h rhythm. LDim did not affect body weight or glucose tolerance. In conclusion, we introduce the first rodent model for disturbed circadian control of sleep due to LAN. We show that internal desynchronization is possible in a 24 h L:D cycle which suggests that a similar desynchronization may explain the association between LAN and human insomnia.

Shift work and cancer risk: potential mechanistic roles of circadian disruption, light at night, and sleep deprivation.

Science.gov (United States)

Haus, Erhard L; Smolensky, Michael H

2013-08-01

Shift work that includes a nighttime rotation has become an unavoidable attribute of today's 24-h society. The related disruption of the human circadian time organization leads in the short-term to an array of jet-lag-like symptoms, and in the long-run it may contribute to weight gain/obesity, metabolic syndrome/type II diabetes, and cardiovascular disease. Epidemiologic studies also suggest increased cancer risk, especially for breast cancer, in night and rotating female shift workers. If confirmed in more controlled and detailed studies, the carcinogenic effect of night and shift work will constitute additional serious medical, economic, and social problems for a substantial proportion of the working population. Here, we examine the possible multiple and interconnected cancer-promoting mechanisms as a consequence of shift work, i.e., repeated disruption of the circadian system, pineal hormone melatonin suppression by exposure to light at night, sleep-deprivation-caused impairment of the immune system, plus metabolic changes favoring obesity and generation of proinflammatory reactive oxygen species. Copyright © 2012 Elsevier Ltd. All rights reserved.

Night myopia studied with an adaptive optics visual analyzer.

Directory of Open Access Journals (Sweden)

Pablo Artal

Full Text Available PURPOSE: Eyes with distant objects in focus in daylight are thought to become myopic in dim light. This phenomenon, often called "night myopia" has been studied extensively for several decades. However, despite its general acceptance, its magnitude and causes are still controversial. A series of experiments were performed to understand night myopia in greater detail. METHODS: We used an adaptive optics instrument operating in invisible infrared light to elucidate the actual magnitude of night myopia and its main causes. The experimental setup allowed the manipulation of the eye's aberrations (and particularly spherical aberration as well as the use of monochromatic and polychromatic stimuli. Eight subjects with normal vision monocularly determined their best focus position subjectively for a Maltese cross stimulus at different levels of luminance, from the baseline condition of 20 cd/m(2 to the lowest luminance of 22 × 10(-6 cd/m(2. While subjects performed the focusing tasks, their eye's defocus and aberrations were continuously measured with the 1050-nm Hartmann-Shack sensor incorporated in the adaptive optics instrument. The experiment was repeated for a variety of controlled conditions incorporating specific aberrations of the eye and chromatic content of the stimuli. RESULTS: We found large inter-subject variability and an average of -0.8 D myopic shift for low light conditions. The main cause responsible for night myopia was the accommodation shift occurring at low light levels. Other factors, traditionally suggested to explain night myopia, such as chromatic and spherical aberrations, have a much smaller effect in this mechanism. CONCLUSIONS: An adaptive optics visual analyzer was applied to study the phenomenon of night myopia. We found that the defocus shift occurring in dim light is mainly due to accommodation errors.

PePSS - A portable sky scanner for measuring extremely low night-sky brightness

Science.gov (United States)

Kocifaj, Miroslav; Kómar, Ladislav; Kundracik, František

2018-05-01

A new portable sky scanner designed for low-light-level detection at night is developed and employed in night sky brightness measurements in a rural region. The fast readout, adjustable sensitivity and linear response guaranteed in 5-6 orders of magnitude makes the device well suited for narrow-band photometry in both dark areas and bright urban and suburban environments. Quasi-monochromatic night-sky brightness data are advantageous in the accurate characterization of spectral power distribution of scattered and emitted light and, also allows for the possibility to retrieve light output patterns from whole-city light sources. The sky scanner can operate in both night and day regimes, taking advantage of the complementarity of both radiance data types. Due to its inherent very high sensitivity the photomultiplier tube could be used in night sky radiometry, while the spectrometer-equipped system component capable of detecting elevated intensities is used in daylight monitoring. Daylight is a source of information on atmospheric optical properties that in turn are necessary in processing night sky radiances. We believe that the sky scanner has the potential to revolutionize night-sky monitoring systems.

Short-term exposure to dim light at night disrupts rhythmic behaviors and causes neurodegeneration in fly models of tauopathy and Alzheimer's disease.

Science.gov (United States)

Kim, Mari; Subramanian, Manivannan; Cho, Yun-Ho; Kim, Gye-Hyeong; Lee, Eunil; Park, Joong-Jean

2018-01-08

The accumulation and aggregation of phosphorylated tau proteins in the brain are the hallmarks for the onset of Alzheimer's disease (AD). In addition, disruptions in circadian rhythms (CRs) with altered sleep-wake cycles, dysregulation of locomotion, and increased memory defects have been reported in patients with AD. Drosophila flies that have an overexpression of human tau protein in neurons exhibit most of the symptoms of human patients with AD, including locomotion defects and neurodegeneration. Using the fly model for tauopathy/AD, we investigated the effects of an exposure to dim light at night on AD symptoms. We used a light intensity of 10 lux, which is considered the lower limit of light pollution in many countries. After the tauopathy flies were exposed to the dim light at night for 3 days, the flies showed disrupted CRs, altered sleep-wake cycles due to increased pTau proteins and neurodegeneration, in the brains of the AD flies. The results indicate that the nighttime exposure of tauopathy/AD model Drosophila flies to dim light disrupted CR and sleep-wake behavior and promoted neurodegeneration. Copyright © 2017 Elsevier Inc. All rights reserved.

NIGHT SKY BRIGHTNESS ABOVE ZAGREB 2012.-2017.

Directory of Open Access Journals (Sweden)

Željko Andreić

2018-01-01

Full Text Available The night sky brightness at the RGN site (near the centre of Zagreb, Croatia was monitored form January 2012. to December 2017. The gathered data show that the average night sky brightness in this period did not change significantly, apart from differences caused by yearly variations in meteorological parameters. The nightly minima, maxima and mean values of the sky brightness do change considerably due to changes in meteorological conditions, often being between 2 and 3 magnitudes. The seasonal probability curves and histograms are constructed and are used to obtain additional information on the light pollution at the RGN site. They reveal that the night sky brightness clutters around two peaks, at about 15.0 mag/arcsec2 and at about 18.2 mag/arcsec2. The tendency to slightly lower brightness values in spring and summer can also be seen in the data. Two peaks correspond to cloudy and clear nights respectively, the difference in brightness between them being about 3 magnitudes. A crude clear/cloudy criterion can be defined too: the minimum between two peaks is around 16.7 mag/arcsec2. The brightness values smaller than thisare attributed to clear nights and vice-versa. Comparison with Vienna and Hong-Kong indicates that the light pollution of Zagreb is a few times larger.

Cloud Coverage Acts as an Amplifier for Ecological Light Pollution in Urban Ecosystems

Science.gov (United States)

Kyba, Christopher C. M.; Ruhtz, Thomas; Fischer, Jürgen; Hölker, Franz

2011-01-01

The diurnal cycle of light and dark is one of the strongest environmental factors for life on Earth. Many species in both terrestrial and aquatic ecosystems use the level of ambient light to regulate their metabolism, growth, and behavior. The sky glow caused by artificial lighting from urban areas disrupts this natural cycle, and has been shown to impact the behavior of organisms, even many kilometers away from the light sources. It could be hypothesized that factors that increase the luminance of the sky amplify the degree of this “ecological light pollution”. We show that cloud coverage dramatically amplifies the sky luminance, by a factor of 10.1 for one location inside of Berlin and by a factor of 2.8 at 32 km from the city center. We also show that inside of the city overcast nights are brighter than clear rural moonlit nights, by a factor of 4.1. These results have important implications for choronobiological and chronoecological studies in urban areas, where this amplification effect has previously not been considered. PMID:21399694

Cloud coverage acts as an amplifier for ecological light pollution in urban ecosystems.

Science.gov (United States)

Kyba, Christopher C M; Ruhtz, Thomas; Fischer, Jürgen; Hölker, Franz

2011-03-02

The diurnal cycle of light and dark is one of the strongest environmental factors for life on Earth. Many species in both terrestrial and aquatic ecosystems use the level of ambient light to regulate their metabolism, growth, and behavior. The sky glow caused by artificial lighting from urban areas disrupts this natural cycle, and has been shown to impact the behavior of organisms, even many kilometers away from the light sources. It could be hypothesized that factors that increase the luminance of the sky amplify the degree of this "ecological light pollution". We show that cloud coverage dramatically amplifies the sky luminance, by a factor of 10.1 for one location inside of Berlin and by a factor of 2.8 at 32 km from the city center. We also show that inside of the city overcast nights are brighter than clear rural moonlit nights, by a factor of 4.1. These results have important implications for choronobiological and chronoecological studies in urban areas, where this amplification effect has previously not been considered.

Effects of age and illumination on night driving: a road test.

Science.gov (United States)

Owens, D Alfred; Wood, Joanne M; Owens, Justin M

2007-12-01

This study investigated the effects of drivers' age and low light on speed, lane keeping, and visual recognition of typical roadway stimuli. Poor visibility, which is exacerbated by age-related changes in vision, is a leading contributor to fatal nighttime crashes. There is little evidence, however, concerning the extent to which drivers recognize and compensate for their visual limitations at night. Young, middle-aged, and elder participants drove on a closed road course in day and night conditions at a "comfortable" speed without speedometer information. During night tests, headlight intensity was varied over a range of 1.5 log units using neutral density filters. Average speed and recognition of road signs decreased significantly as functions of increased age and reduced illumination. Recognition of pedestrians at night was significantly enhanced by retroreflective markings of limb joints as compared with markings of the torso, and this benefit was greater for middle-aged and elder drivers. Lane keeping showed nonlinear effects of lighting, which interacted with task conditions and drivers' lateral bias, indicating that older drivers drove more cautiously in low light. Consistent with the hypothesis that drivers misjudge their visual abilities at night, participants of all age groups failed to compensate fully for diminished visual recognition abilities in low light, although older drivers behaved more cautiously than the younger groups. These findings highlight the importance of educating all road users about the limitations of night vision and provide new evidence that retroreflective markings of the limbs can be of great benefit to pedestrians' safety at night.

The chemistry of artificial lighting devices lamps, phosphors and cathode ray tubes

CERN Document Server

Ropp, Richard C

2013-01-01

Both the early use of artificial lighting and current manufacturing methods concerning incandescent and fluorescent lamps are covered in this book. The protocols for manufacture of fluorescent lamp phosphors and those used in cathode ray tubes are also treated in some detail. This text surveys the amazing, vast array of artificial lighting devices known to date in terms of how they arose and are, or have been used by mankind. A complete description of the formulations and methodology for manufacturing all known phosphors is given. The book will serve as a repository of such phosphor manufacturing methods, including that of cathode ray tube phosphors. Methods of manufacture of lamp parts are also presented, including that of tungsten wire. The original approaches used are described as well as improvements in technology. These will serve as comparative methods for present day manufacture of these components. A history of the lamp industry is presented. Several methods are given which may serve as a source for f...

Light pollution modifies the expression of daily rhythms and behavior patterns in a nocturnal primate.

Directory of Open Access Journals (Sweden)

Thomas Le Tallec

Full Text Available Among anthropogenic pressures, light pollution altering light/dark cycles and changing the nocturnal component of the environment constitutes a threat for biodiversity. Light pollution is widely spread across the world and continuously growing. However, despite the efforts realized to describe and understand the effects of artificial lighting on fauna, few studies have documented its consequences on biological rhythms, behavioral and physiological functions in nocturnal mammals. To determine the impacts of light pollution on nocturnal mammals an experimental study was conducted on a nocturnal primate, the grey mouse lemur Microcebus murinus. Male mouse lemurs (N = 8 were exposed 14 nights to moonlight treatment and then exposed 14 nights to light pollution treatment. For both treatments, chronobiological parameters related to locomotor activity and core temperature were recorded using telemetric transmitters. In addition, at the end of each treatment, the 14(th night, nocturnal and feeding behaviors were explored using an infrared camera. Finally, throughout the study, body mass and daily caloric food intake were recorded. For the first time in a nocturnal primate, light pollution was demonstrated to modify daily rhythms of locomotor activity and core temperature especially through phase delays and increases in core temperature. Moreover, nocturnal activity and feeding behaviors patterns were modified negatively. This study suggests that light pollution induces daily desynchronization of biological rhythms and could lead to seasonal desynchronization with potential deleterious consequences for animals in terms of adaptation and anticipation of environmental changes.

Light pollution modifies the expression of daily rhythms and behavior patterns in a nocturnal primate.

Science.gov (United States)

Le Tallec, Thomas; Perret, Martine; Théry, Marc

2013-01-01

Among anthropogenic pressures, light pollution altering light/dark cycles and changing the nocturnal component of the environment constitutes a threat for biodiversity. Light pollution is widely spread across the world and continuously growing. However, despite the efforts realized to describe and understand the effects of artificial lighting on fauna, few studies have documented its consequences on biological rhythms, behavioral and physiological functions in nocturnal mammals. To determine the impacts of light pollution on nocturnal mammals an experimental study was conducted on a nocturnal primate, the grey mouse lemur Microcebus murinus. Male mouse lemurs (N = 8) were exposed 14 nights to moonlight treatment and then exposed 14 nights to light pollution treatment. For both treatments, chronobiological parameters related to locomotor activity and core temperature were recorded using telemetric transmitters. In addition, at the end of each treatment, the 14(th) night, nocturnal and feeding behaviors were explored using an infrared camera. Finally, throughout the study, body mass and daily caloric food intake were recorded. For the first time in a nocturnal primate, light pollution was demonstrated to modify daily rhythms of locomotor activity and core temperature especially through phase delays and increases in core temperature. Moreover, nocturnal activity and feeding behaviors patterns were modified negatively. This study suggests that light pollution induces daily desynchronization of biological rhythms and could lead to seasonal desynchronization with potential deleterious consequences for animals in terms of adaptation and anticipation of environmental changes.

Dark Skies Awareness through the GLOBE at Night Citizen-Science Campaign

Science.gov (United States)

Walker, C. E.

2011-10-01

The emphasis in the international citizen-science, star-hunting campaign, GLOBE at Night, is in bringing awareness to the public on issues of light pollution. Light pollution threatens not only observatory sites and our "right to starlight", but can affect energy consumption, wildlife and health. GLOBE at Night has successfully reached a few hundred thousand citizen-scientists during the annual 2-week campaign over the past 6 years. Provided is an overview, update and discussion of what steps can be taken to improve programs like GLOBE at Night.

Astronomy Meets the Environmental Sciences: Using GLOBE at Night Data

Science.gov (United States)

Barringer, D.; Walker, C. E.; Pompea, S. M.; Sparks, R. T.

2011-09-01

The GLOBE at Night database now contains over 52,000 observations from the five annual two-week campaigns. It can be used as a resource to explore various issues related to light pollution and our environment. Students can compare data over time to look for changes and trends. For example, they can compare the data to population density or with nighttime photography and spectroscopy of lights. The data can be used in a lighting survey, to search for dark sky oases or to monitor ordinance compliance. Students can study effects of light pollution on animals, plants, human health, safety, security, energy consumption, and cost. As an example, we used data from the GLOBE at Night project and telemetry tracking data of lesser long-nosed bats obtained by the Arizona Game and Fish Department to study the effects of light pollution on the flight paths of the bats between their day roosts and night foraging areas around the city of Tucson, AZ. With the visual limiting magnitude data from GLOBE at Night, we ran a compositional analysis with respect to the bats' flight paths to determine whether the bats were selecting for or against flight through regions of particular night sky brightness levels. We found that the bats selected for the regions in which the limiting sky magnitudes fell between the ranges of 2.8-3.0 to 3.6-3.8 and 4.4-4.6 to 5.0-5.2, suggesting that the lesser long-nosed bat can tolerate a fair degree of urbanization. We also compared this result to contour maps created with digital Sky Quality Meter (http://www.unihedron.com) data.

Disruptive effects of light pollution on sleep in free-living birds: Season and/or light intensity-dependent?

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Raap, Thomas; Sun, Jiachen; Pinxten, Rianne; Eens, Marcel

2017-11-01

Light pollution or artificial light at night (ALAN) is an increasing anthropogenic environmental pollutant posing an important potential threat for wildlife. Evidence of its effects on animal physiology and behaviour is accumulating. However, in order to effectively mitigate light pollution it is important to determine which factors contribute to the severity of effects of ALAN. In this experimental study we explored whether there are seasonal-dependent effects of ALAN on sleep in free-living great tits (Parus major), an important model species. Additionally, we looked at whether light intensity determined the severity of effects of ALAN on sleep. We therefore exposed animals to artificial light inside the nest box (3lx) in December (winter) and February (pre-breeding season). Results from February were compared with the results from a previous study in February, using a lower light intensity (1.6lx). We found little evidence for a season-dependent response. Effects of ALAN hardly differed between high and low light intensity. ALAN disrupted sleep with as main effect a decrease in sleep duration (≈-40min) as animals woke up earlier (≈-24min). However, compared to a natural dark situation sleep onset was delayed by high but not by low light intensity of ALAN. Our study underlines earlier found disruptive effects of ALAN on sleep of free-living animals. While we found no conclusive evidence for seasonal or light intensity-dependent effects of ALAN, additional experimental work using lower light intensities might show such differences. Examining potential management options is crucial in mitigating disruptive effects of light pollution, which will be an important focus for future studies. Copyright © 2017 Elsevier B.V. All rights reserved.

Photometric Assessment of Night Sky Quality over Chaco Culture National Historical Park

Science.gov (United States)

Hung, Li-Wei; Duriscoe, Dan M.; White, Jeremy M.; Meadows, Bob; Anderson, Sharolyn J.

2018-06-01

The US National Park Service (NPS) characterizes night sky conditions over Chaco Culture National Historical Park using measurements in the park and satellite data. The park is located near the geographic center of the San Juan Basin of northwestern New Mexico and the adjacent Four Corners state. In the park, we capture a series of night sky images in V-band using our mobile camera system on nine nights from 2001 to 2016 at four sites. We perform absolute photometric calibration and determine the image placement to obtain multiple 45-million-pixel mosaic images of the entire night sky. We also model the regional night sky conditions in and around the park based on 2016 VIIRS satellite data. The average zenith brightness is 21.5 mag/arcsec2, and the whole sky is only ~16% brighter than the natural conditions. The faintest stars visible to naked eyes have magnitude of approximately 7.0, reaching the sensitivity limit of human eyes. The main impacts to Chaco’s night sky quality are the light domes from Albuquerque, Rio Rancho, Farmington, Bloomfield, Gallup, Santa Fe, Grants, and Crown Point. A few of these light domes exceed the natural brightness of the Milky Way. Additionally, glare sources from oil and gas development sites are visible along the north and east horizons. Overall, the night sky quality at Chaco Culture National Historical Park is very good. The park preserves to a large extent the natural illumination cycles, providing a refuge for crepuscular and nocturnal species. During clear and dark nights, visitors have an opportunity to see the Milky Way from nearly horizon to horizon, complete constellations, and faint astronomical objects and natural sources of light such as the Andromeda Galaxy, zodiacal light, and airglow.

The propagation of light pollution in the atmosphere

Science.gov (United States)

Cinzano, P.; Falchi, F.

2012-12-01

Recent methods to map artificial night-sky brightness and stellar visibility across large territories or their distribution over the entire sky at any site are based on computation of the propagation of light pollution with Garstang models, a simplified solution of the radiative transfer problem in the atmosphere that allows fast computation by reducing it to a ray-tracing approach. They are accurate for a clear atmosphere, when a two-scattering approximation is acceptable, which is the most common situation. We present here up-to-date extended Garstang models (EGM), which provide a more general numerical solution for the radiative transfer problem applied to the propagation of light pollution in the atmosphere. We also present the LPTRAN software package, an application of EGM to high-resolution Defense Meteorological Satellite Program (DMSP) Operational Linescan System (OLS) satellite measurements of artificial light emission and to GTOPO30 (Global 30 Arcsecond) digital elevation data, which provides an up-to-date method to predict the artificial brightness distribution of the night sky at any site in the world at any visible wavelength for a broad range of atmospheric situations and the artificial radiation density in the atmosphere across the territory. EGM account for (i) multiple scattering, (ii) wavelengths from 250 nm to infrared, (iii) the Earth's curvature and its screening effects, (iv) site and source elevation, (v) many kinds of atmosphere with the possibility of custom set-up (e.g. including thermal inversion layers), (vi) a mix of different boundary-layer aerosols and tropospheric aerosols, with the possibility of custom set-up, (vii) up to five aerosol layers in the upper atmosphere, including fresh and aged volcanic dust and meteoric dust, (viii) variations of the scattering phase function with elevation, (ix) continuum and line gas absorption from many species, ozone included, (x) up to five cloud layers, (xi) wavelength-dependent bidirectional

Measuring and mapping the night sky brightness of Perth, Western Australia

Science.gov (United States)

Biggs, James D.; Fouché, Tiffany; Bilki, Frank; Zadnik, Marjan G.

2012-04-01

In order to study the light pollution produced in the city of Perth, Western Australia, we have used a hand-held sky brightness meter to measure the night sky brightness across the city. The data acquired facilitated the creation of a contour map of night sky brightness across the 2400 km2 area of the city - the first such map to be produced for a city. Importantly, this map was created using a methodology borrowed from the field of geophysics - the well proven and rigorous techniques of geostatistical analysis and modelling. A major finding of this study is the effect of land use on night sky brightness. By overlaying the night sky brightness map on to a suitably processed Landsat satellite image of Perth we found that locations near commercial and/or light industrial areas have a brighter night sky, whereas locations used for agriculture or having high vegetation coverage have a fainter night sky than surrounding areas. Urban areas have intermediate amounts of vegetation and are intermediate in brightness compared with the above-mentioned land uses. Regions with a higher density of major highways also appear to contribute to increased night sky brightness. When corrected for the effects of direct illumination from high buildings, we found that the night sky brightness in the central business district (CBD) is very close to that expected for a city of Perth's population from modelling work and observations obtained in earlier studies. Given that our night sky brightness measurements in Perth over 2009 and 2010 are commensurate with that measured in Canadian cities over 30 years earlier implies that the various lighting systems employed in Perth (and probably most other cities) have not been optimised to minimize light pollution over that time. We also found that night sky brightness diminished with distance with an exponent of approximately -0.25 ± 0.02 from 3.5 to 10 km from the Perth CBD, a region characterized by urban and commercial land use. For distances

Light pollution is greatest within migration passage areas for nocturnally-migrating birds around the world.

Science.gov (United States)

Cabrera-Cruz, Sergio A; Smolinsky, Jaclyn A; Buler, Jeffrey J

2018-02-19

Excessive or misdirected artificial light at night (ALAN) produces light pollution that influences several aspects of the biology and ecology of birds, including disruption of circadian rhythms and disorientation during flight. Many migrating birds traverse large expanses of land twice every year at night when ALAN illuminates the sky. Considering the extensive and increasing encroachment of light pollution around the world, we evaluated the association of the annual mean ALAN intensity over land within the geographic ranges of 298 nocturnally migrating bird species with five factors: phase of annual cycle, mean distance between breeding and non-breeding ranges, range size, global hemisphere of range, and IUCN category of conservation concern. Light pollution within geographic ranges was relatively greater during the migration season, for shorter-distance migrants, for species with smaller ranges, and for species in the western hemisphere. Our results suggest that migratory birds may be subject to the effects of light pollution particularly during migration, the most critical stage in their annual cycle. We hope these results will spur further research on how light pollution affects not only migrating birds, but also other highly mobile animals throughout their annual cycle.

The emission function of ground-based light sources: State of the art and research challenges

Science.gov (United States)

Solano Lamphar, Héctor Antonio

2018-05-01

To understand the night sky radiance generated by the light emissions of urbanised areas, different researchers are currently proposing various theoretical approaches. The distribution of the radiant intensity as a function of the zenith angle is one of the most unknown properties on modelling skyglow. This is due to the collective effects of the artificial radiation emitted from the ground-based light sources. The emission function is a key property in characterising the sky brightness under arbitrary conditions, therefore it is required by modellers, environmental engineers, urban planners, light pollution researchers, and experimentalists who study the diffuse light of the night sky. As a matter of course, the emission function considers the public lighting system, which is in fact the main generator of the skyglow. Still, another class of light-emitting devices are gaining importance since their overuse and the urban sprawl of recent years. This paper will address the importance of the emission function in modelling skyglow and the factors involved in its characterization. On this subject, the author's intention is to organise, integrate, and evaluate previously published research in order to state the progress of current research toward clarifying this topic.

Carbon dot-Au(i)Ag(0) assembly for the construction of an artificial light harvesting system.

Science.gov (United States)

Jana, Jayasmita; Aditya, Teresa; Pal, Tarasankar

2018-03-06

Artificial light harvesting systems (LHS) with inorganic counterparts are considered to be robust as well as mechanistically simple, where the system follows the donor-acceptor principle with an unchanged structural pattern. Plasmonic gold or silver nanoparticles are mostly chosen as inorganic counterparts to design artificial LHS. To capitalize on its electron accepting capability, Au(i) has been considered in this work for the synergistic stabilization of a system with intriguingly fluorescing silver(0) clusters produced in situ. Thus a stable fluorescent Au(i)Ag(0) assembly is generated with electron accepting capabilities. On the other hand, carbon dots have evolved as new fluorescent probes due to their unique physicochemical properties. Utilizing the simple electronic behavior of carbon dots, an electronic interaction between the fluorescent Au(i)Ag(0) and a carbon dot has been investigated for the construction of a new artificial light harvesting system. This coinage metal assembly allows surface energy transfer where it acts as an acceptor, while the carbon dot behaves as a good donor. The energy transfer efficiency has been calculated experimentally to be significant (81.3%) and the Au(i)Ag(0)-carbon dot assembly paves the way for efficient artificial LHS.

Light Pollution: The Global View

Science.gov (United States)

Schwarz, H. E.

2003-04-01

It is only since recent years that the importance of the effects of outdoor lighting on the night-time environment and on the physical and mental health of humans is recognized on a wider scale. The related issue of light pollution is a particularly complex one, with potential conflicts of interest between the utilities, environmentalists, astronomers, the lighting industry and various government departments. Energy politics are always a sensitive issue, and light pollution is no exception to this rule. The effects of light pollution on flora, fauna -including humans and their widely varying night-time activities- are often subtle and need extensive field studies to be quantified in a sensible manner. The present conference, initiated by Commission 50 of the International Astronomical Union, is an attempt to bring together the astronomical community, the lighting industry, end-users, the utilities, and public authorities for a discussion and an exchange of ideas and information that will create goodwill among these groups and will thus contribute to making the global efforts to reduce pollution more efficient and effective. Radio frequency pollution was also discussed in the context of radio astronomy and its efforts to create radio-quiet zones in collaboration with the government authorities that allocate frequency bands to the various users -mainly the telecommunications industry- and to protect the major planned and present radio observatories of the world. The 3-day conference was attended by more than 130 representatives from 12 countries of all the above-mentioned groups, and a wide range of topics was discussed. Some of the highlights were: The presentation of the 1st world atlas of artificial night sky brightness (Cinzano et al.); the article by the International Darksky Association on their world-wide efforts to curb light pollution (Alvarez del Castillo et al.); the laws controlling light pollution implemented in Spain (Diaz et al.) and Chile (Sanhueza et

Progressive decrease of melatonin production over consecutive days of simulated night work.

Science.gov (United States)

Dumont, Marie; Paquet, Jean

2014-12-01

Decreased melatonin production, due to nighttime exposure to light, has been proposed as one of the physiological mechanisms increasing cancer risk in night workers. However, few studies measured melatonin production in night workers, and most of these studies did not measure melatonin over 24 h. One study compared total melatonin production between day and night shifts in rotating night workers and did not find significant differences. However, without baseline measures, it was not possible to exclude that melatonin production was reduced during both day and night work. Here, we used data collected in a simulation study of night work to determine the effect of night work on both nighttime and 24-h melatonin production, during three consecutive days of simulated night work. Thirty-eight healthy subjects (15 men, 23 women; 26.6 ± 4.2 years) participated in a 6-d laboratory study. Circadian phase assessments were made with salivary dim light melatonin onset (DLMO) on the first and last days. Simulated day work (09:00-17:00 h) occurred on the second day, followed by three consecutive days of simulated night work (00:00-08:00 h). Light intensity at eye level was set at 50 lux during both simulated day and night work. The subjects were divided into three matched groups exposed to specific daytime light profiles that produced various degrees of circadian phase delays and phase advances. Melatonin production was estimated with the excretion of urinary 6-sulfatoxymelatonin (aMT6s). For the entire protocol, urine was collected every 2 h, except for the sleep episodes when the interval was 8 h. The aMT6s concentration in each sample was multiplied by the urine volume and then added to obtain total aMT6s excretion during nighttime (00:00-08:00 h) and during each 24-h day (00:00-00:00 h). The results showed that melatonin production progressively decreased over consecutive days of simulated night work, both during nighttime and over the 24 h. This

Multi-Band Intra-Night Optical Variability of BL Lacertae

Directory of Open Access Journals (Sweden)

Haritma Gaur

2017-12-01

Full Text Available We monitored BL Lacertae frequently during 2014–2016 when it was generally in a high state. We searched for intra-day variability for 43 nights using quasi-simultaneous measurements in the B, V, R, and I bands (totaling 143 light curves; the typical sampling interval was about eight minutes. On hour-like timescales, BL Lac exhibited significant variations during 13 nights in various optical bands. Significant spectral variations are seen during most of these nights such that the optical spectrum becomes bluer when brighter. The amplitude of variability is usually greater for longer observations but is lower when BL Lac is brighter. No evidence for periodicities or characteristic variability time-scales in the light curves was found. The color variations are mildly chromatic on long timescales.

Integrated optimization of temperature, CO2, screen use and artificial lighting in greenhouse crops

DEFF Research Database (Denmark)

Aaslyng, J.M.; Körner, O.; Andreassen, A.U.

2005-01-01

A leaf photosynthesis model is suggested for integrated optimization of temperature, CO2, screen use and artificial lighting in greenhouse crops. Three different approaches for the optimization are presented. First, results from greenhouse experiments with model based optimization are presented....... Second, a model-based analysis of a commercial grower's production possibility is shown. Third, results from a simulation of the effect of a new lighting strategy are demonstrated. The results demonstrate that it is possible to optimize plant production by using a model-based integrated optimization...... of temperature, CO2, and light in the greenhouse...

Light pollution: measuring and modelling skyglow. An application in two Portuguese reserves

Science.gov (United States)

Lima, Raul Cerveira Pinto Sousa

Outdoors human-made lighting at night causes sky glow, one of the effects of light pollution. Sky glow is rising with the growth of world population. Urban inhabitants are increasingly deprived from a starry sky. However, since light propagates to regions far from where it is produced, light pollution spreads to places where few or none artificial light at night existed, disturbing the quality of the night sky. In this work we assess for the first time the sky brightness of two regions in Portugal, the Peneda-Geres National Park, and the recently created Starlight Reserve Dark Sky® Alqueva. We used a portable unit, a Unihedron Sky Quality Meter-L (SQM-L), to measure the luminance of the night sky. We also tested the SQM-L in a laboratory to a more thorough analysis of the device, and to check the effect of polarization on the unit, suggested by our observations and other users. Our results suggest that the SQM-L is not affected by any measurable effect of polarization, but some guidelines to use the SQM-L in the field are provided based on our work. The data from the field measurement was used to compare to one light pollution propagation model (Kocifaj, 2007), using VIIRS DNB satellite upwards radiance as input to the model. The results obtained from the model are favourably compared to the field measurements. We proceeded to a set of tests with the model to find the best fit. Our best results were achieved by analysing the data by night rather than the global set of data. Our first results were used to apply to the classification of the region of Alqueva to a Starlight Tourism Destination. That classification was attained during the course of this work (December 2011). A guideline on the Peneda-Geres National Park was also implemented after our first results were provided. We believe we have achieved a set of results in a set of parallel issues all related to light pollution that we hope may contribute to the current knowledge on this area of research.

Study on spatial-temporal change of Changsha-Zhuzhou-Xiangtan urban agglomeration based on DMSP / OLS night light data

Science.gov (United States)

Li, Mao; Li, Lel-in

2018-03-01

For the sake of curbing the spreading of Changsha-Zhuzhou-Xiangtan urban agglomeration and spatial disorder in the process of urbanization development on the regional bearing capacity of land resources and ecological environment and assisting to plan the integration process of ChangZhuTan,this paper uses the DMSP/OLS night light data of Chang ZhuTan in 1992 to 2013 to invert the urbanization process index of ChangZhuTan urban agglomeration. Based on the two scales of time and space, this paper analyzes the average index of lights, the speed of urban expansion and urban compactness index et al and studies the temporal and spatial characteristics of ChangZhuTan urban agglomeration in this period.

Physical behaviour of anthropogenic light propagation into the nocturnal environment.

Science.gov (United States)

Aubé, Martin

2015-05-05

Propagation of artificial light at night (ALAN) in the environment is now known to have non negligible consequences on fauna, flora and human health. These consequences depend on light levels and their spectral power distributions, which in turn rely on the efficiency of various physical processes involved in the radiative transfer of this light into the atmosphere and its interactions with the built and natural environment. ALAN can affect the living organisms by direct lighting and indirect lighting (scattered by the sky and clouds and/or reflected by local surfaces). This paper mainly focuses on the behaviour of the indirect light scattered under clear sky conditions. Various interaction processes between anthropogenic light sources and the natural environment are discussed. This work mostly relies on a sensitivity analysis conducted with the light pollution radiative transfer model, Illumina (Aubé et al. 2005 Light pollution modelling and detection in a heterogeneous environment: toward a night-time aerosol optical depth retrieval method. In Proc. SPIE 2005, vol. 5890, San Diego, California, USA). More specifically, the impact of (i) the molecular and aerosol scattering and absorption, (ii) the second order of scattering, (iii) the topography and obstacle blocking, (iv) the ground reflectance and (v) the spectrum of light devices and their angular emission functions are examined. This analysis considers different behaviour as a function of the distance from the city centre, along with different zenith viewing angles in the principal plane. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Seeing Stars: A GLOBE at Night Campaign Update

Science.gov (United States)

Walker, Constance E.; Pompea, S. M.; Sparks, R. T.; Newhouse, M.

2012-01-01

The emphasis in the international citizen-science, star-hunting campaign, GLOBE at Night, is in bringing awareness to the public on issues of light pollution. Light pollution threatens not only observatory sites and our "right to starlight", but can affect energy consumption, wildlife and health. GLOBE at Night has successfully reached a few 100,000 citizen-scientists. What has done in the last year to contribute to its success? • To promote the campaign via popular social media, GLOBE at Night created Facebook and Twitter pages. • Videos have been created for 4 out of 8 Dark Skies Rangers activities. • Sky brightness measurements can be submitted in real time with smart phones or tablets using the new Web application at www.globeatnight.org/webapp/. The location, date and time register automatically. • As a proto-type, an adopt-a-street program had people in Tucson take measurements every mile for the length of the street. Grid measurements canvassed the town, allowing for comparisons of light levels over time. • The increase to 2 campaigns in 2011 re-enforces these studies. In 2012, the campaign will be offered 4 times for 10 days a month: January 14-23, February 12-21, March 13-22 and April 11-20. • A new Web application (www.globeatnight.org/mapapp/) allows for mapping GLOBE at Night data points within a specified distance around a city or area of choice. The resulting maps are bookmarkable and shareable. • NOAO and Arizona Game and Fish Department started a project with GLOBE at Night data and bat telemetry to examine a dark skies corridor in Tucson where endangered bats fly. While providing these updates to the GLOBE at Night program, the presentation will highlight the education and outreach value of the program's resources and outcomes, lessons learned, successes and pitfalls in communicating awareness with the public and attracting young people to study science.

Circadian Phase-Shifting Effects of Bright Light, Exercise, and Bright Light + Exercise.

Science.gov (United States)

Youngstedt, Shawn D; Kline, Christopher E; Elliott, Jeffrey A; Zielinski, Mark R; Devlin, Tina M; Moore, Teresa A

2016-02-26

Limited research has compared the circadian phase-shifting effects of bright light and exercise and additive effects of these stimuli. The aim of this study was to compare the phase-delaying effects of late night bright light, late night exercise, and late evening bright light followed by early morning exercise. In a within-subjects, counterbalanced design, 6 young adults completed each of three 2.5-day protocols. Participants followed a 3-h ultra-short sleep-wake cycle, involving wakefulness in dim light for 2h, followed by attempted sleep in darkness for 1 h, repeated throughout each protocol. On night 2 of each protocol, participants received either (1) bright light alone (5,000 lux) from 2210-2340 h, (2) treadmill exercise alone from 2210-2340 h, or (3) bright light (2210-2340 h) followed by exercise from 0410-0540 h. Urine was collected every 90 min. Shifts in the 6-sulphatoxymelatonin (aMT6s) cosine acrophase from baseline to post-treatment were compared between treatments. Analyses revealed a significant additive phase-delaying effect of bright light + exercise (80.8 ± 11.6 [SD] min) compared with exercise alone (47.3 ± 21.6 min), and a similar phase delay following bright light alone (56.6 ± 15.2 min) and exercise alone administered for the same duration and at the same time of night. Thus, the data suggest that late night bright light followed by early morning exercise can have an additive circadian phase-shifting effect.

Artificial skin and patient simulator comprising the artificial skin

NARCIS (Netherlands)

2011-01-01

The invention relates to an artificial skin (10, 12, 14), and relates to a patient simulator (100) comprising the artificial skin. The artificial skin is a layered structure comprising a translucent cover layer (20) configured for imitating human or animal skin, and comprising a light emitting layer

Dim light at night interacts with intermittent hypoxia to alter cognitive and affective responses.

Science.gov (United States)

Aubrecht, Taryn G; Weil, Zachary M; Magalang, Ulysses J; Nelson, Randy J

2013-07-01

Obstructive sleep apnea (OSA) and dim light at night (dLAN) have both been independently associated with alterations in mood and cognition. We aimed to determine whether dLAN would interact with intermittent hypoxia (IH), a condition characteristic of OSA, to alter the behavioral, cognitive, and affective responses. Adult male mice were housed in either standard lighting conditions (14:10-h light-dark cycle; 150 lux:0 lux) or dLAN (150 lux:5 lux). Mice were then exposed to IH (15 cycles/h, 8 h/day, FiO2 nadir of 5%) for 3 wk, then tested in assays of affective and cognitive responses; brains were collected for dendritic morphology and PCR analysis. Exposure to dLAN and IH increased anxiety-like behaviors, as assessed in the open field, elevated plus maze, and the light/dark box. dLAN and IH increased depressive-like behaviors in the forced swim test. IH impaired learning and memory performance in the passive avoidance task; however, no differences were observed in spatial working memory, as assessed by y-maze or object recognition. IH combined with dLAN decreased cell body area in the CA1 and CA3 regions of the hippocampus. Overall, IH decreased apical spine density in the CA3, whereas dLAN decreased spine density in the CA1 of the hippocampus. TNF-α gene expression was not altered by IH or lighting condition, whereas VEGF expression was increased by dLAN. The combination of IH and dLAN provokes negative effects on hippocampal dendritic morphology, affect, and cognition, suggesting that limiting nighttime exposure to light in combination with other established treatments may be of benefit to patients with OSA.

Activity Patterns during Food Provisioning Are Affected by Artificial Light in Free Living Great Tits (Parus major)

NARCIS (Netherlands)

Titulaer, M.; Spoelstra, K.; Lange, C.Y.M.J.G.; Visser, M.E.

2012-01-01

Artificial light may have severe ecological consequences but there is limited experimental work to assess these consequences. We carried out an experimental study on a wild population of great tits (Parus major) to assess the impact of light pollution on daily activity patterns during the chick

Association between light exposure at night and insomnia in the general elderly population: the HEIJO-KYO cohort.

Science.gov (United States)

Obayashi, Kenji; Saeki, Keigo; Kurumatani, Norio

2014-11-01

Chronic circadian misalignment between the internal and environmental rhythms, which is typically related to night-shift work and clock-gene variants, is associated with disruption of suprachiasmatic nucleus function and increased risk of insomnia. Under controlled laboratory conditions, light at night (LAN) suppresses melatonin secretion, delays the internal biological rhythm, and reduces sleepiness. Therefore, LAN exposure may cause circadian misalignment and insomnia, though it remains unclear in real-life situations whether LAN exposure is associated with insomnia. To evaluate an association between LAN exposure and sleep quality in home settings, we conducted a cross-sectional community-based study in 857 elderly individuals (mean age, 72.2 years). We evaluated bedroom light intensity using a light meter and subjectively and objectively measured sleep quality using the Pittsburgh Sleep Quality Index and an actigraph, respectively, along with urinary 6-sulfatoxymelatonin excretion. Compared with the lowest quartile group of LAN intensity, the highest quartile group revealed a significantly higher odds ratio (OR) for subjective insomnia in a multivariate model adjusted for age, gender, body mass index, daytime physical activity, urinary 6-sulfatoxymelatonin excretion, bedtime, rising time, and day length (adjusted OR, 1.61, 95% confidence interval, 1.05-2.45, p=0.029). In addition, higher OR for subjective insomnia was significantly associated with the increase in quartiles of LAN intensity (ptrend=0.043). Consistently, we observed significant association trends between the increase in quartiles of LAN intensity and poorer actigraphic sleep quality, including decreased sleep efficiency, prolonged sleep-onset latency, increased wake-after-sleep onset, shortened total sleep time, and delayed sleep-mid time in multivariate models adjusted for the covariates mentioned above (all ptrend<0.001). In conclusion, we demonstrated that LAN exposure in home settings is

Engaging the Public in the Citizen Science GLOBE at Night Campaign

Science.gov (United States)

Walker, Constance E.; Sparks, R. T.; Pompea, S. M.

2011-05-01

The emphasis in the international star-hunting campaign, GLOBE at Night, is in bringing awareness to the public on issues of light pollution. Light pollution threatens not only observatory sites and our "right to starlight", but can affect energy consumption, wildlife and health. GLOBE at Night has successfully reached a few 100,000 citizen-scientists. What steps can be taken to improve it? To promote the campaign via popular social media, GLOBE at Night created Facebook and Twitter pages. To increase participation in the 2011 campaign, children and adults submitted their sky brightness measurements in real time with smart phones or tablets using the web application at www.globeatnight.org/webapp/. With smart phones and tablets, the location, date and time register automatically. For those without smart mobile devices, user-friendly tools on the GLOBE at Night report page were reconfigured to determine latitude and longitude more easily and accurately. To increase the robustness of the data, 2 new approaches were taken. GLOBE at Night prototyped an "Adopt a Street” program in Tucson. The aim was for people to adopt different major or semi-major streets and take measurements every mile or so for the length of the street. The grid of measurements would canvas the town, allowing for comparisons of light levels over time (hours, days, years) or search for dark sky oases or light polluted areas. The increase to 2 campaigns in 2011 re-enforces these studies. The intent is to offer the program year-round for seasonal studies. The data can also be used to compare with datasets on wildlife, health, and energy consumption. Recently, NOAO and the Arizona Game and Fish Department have started a project with GLOBE at Night data and bat telemetry to examine a dark skies corridor in Tucson where the endangered bats fly. In our presentation, results of our efforts are discussed.

Circadian and Melatonin Disruption by Exposure to Light at Night Drives Intrinsic Resistance to Tamoxifen Therapy in Breast Cancer

Science.gov (United States)

Dauchy, Robert T.; Xiang, Shulin; Mao, Lulu; Brimer, Samantha; Wren, Melissa A.; Yuan, Lin; Anbalagan, Muralidharan; Hauch, Adam; Frasch, Tripp; Rowan, Brian G.; Blask, David E.; Hill, Steven M.

2014-01-01

Resistance to endocrine therapy is a major impediment to successful treatment of breast cancer. Preclinical and clinical evidence links resistance to anti-estrogen drugs in breast cancer cells with the overexpression and/or activation of various pro-oncogenic tyrosine kinases. Disruption of circadian rhythms by night shift work or disturbed sleep-wake cycles may lead to an increased risk of breast cancer and other diseases. Moreover, light exposure at night (LEN) suppresses the nocturnal production of melatonin that inhibits breast cancer growth. In this study, we used a rat model of ERα+ MCF-7 tumor xenografts to demonstrate how altering light/dark cycles with dim LEN (dLEN) speeds the development of breast tumors, increasing their metabolism and growth and conferring an intrinsic resistance to tamoxifen therapy. These characters were not produced in animals where circadian rhythms were not disrupted, or in animals subjected to dLEN if they received nocturnal melatonin replacement. Strikingly, our results also showed that melatonin acted both as a tumor metabolic inhibitor and a circadian-regulated kinase inhibitor to re-establish the sensitivity of breast tumors to tamoxifen and tumor regression. Together, our findings show how dLEN-mediated disturbances in nocturnal melatonin production can render tumors insensitive to tamoxifen. PMID:25062775

[Effects of low-light stress on photosynthetic characteristics of Paris polyphylla var. chinensis in artificial domestication cultivation].

Science.gov (United States)

Zheng, Shun-lin; Tian, Meng-liang; Liu, Jin-liang; Zhao, Ting-ting; Zhang, Zhong

2014-09-01

To decide on the optimum artificial domestication cultivation light environment for Paris polyphylla var. chinensis through investigating the effect of light intensity on leaf's gas exchange parameters, photosynthetic parameters, light saturation point and compensation point of Paris polyphylla var. chinensis. Different low-light stress gradients' effect on the growth of Paris polyphylla var. chinensis was compared with no low-light stress treatment through calculating leaf's gas exchange parameters, photosynthetic parameters, light saturation point and compensation point, and then all these parameters were statistically analyzed. Light intensity had significant influence on the photosynthetic characteristics of Paris polyphylla var. chinensis. With the strengthening of the low-light stress, chlorophyll content, gas exchange parameters, photosynthetic parameters P., AQY and light saturation point all gradually increased at first, and then decreased. However, both photosynthetic parameters Rd and light compensation point firstly decreased and then rose again. These results showed that too strong or too weak light intensity affected the optimization of photosynthetic parameters of Paris polyphylla var. chinensis. The optimal illuminance for each parameter was not completely same, but they could all reach a relative ideal state when the shading ranges between 40% and 60%. However, photosynthetic parameters deteriorated rapidly when the shading surpass 80%. For artificially cultivating Paris polyphylla var. chinensis in Baoxing,Sichuan or the similar ecological region, shading 40%-60% is the optimal light environment, which can enhance the photosynthesis of Paris polyphylla var. chinensis and promote the accumulation of photosynthetic products.

Long-term dim light during nighttime changes activity patterns and space use in experimental small mammal populations.

Science.gov (United States)

Hoffmann, Julia; Palme, Rupert; Eccard, Jana Anja

2018-07-01

Artificial light at night (ALAN) is spreading worldwide and thereby is increasingly interfering with natural dark-light cycles. Meanwhile, effects of very low intensities of light pollution on animals have rarely been investigated. We explored the effects of low intensity ALAN over seven months in eight experimental bank vole (Myodes glareolus) populations in large grassland enclosures over winter and early breeding season, using LED garden lamps. Initial populations consisted of eight individuals (32 animals per hectare) in enclosures with or without ALAN. We found that bank voles under ALAN experienced changes in daily activity patterns and space use behavior, measured by automated radiotelemetry. There were no differences in survival and body mass, measured with live trapping, and none in levels of fecal glucocorticoid metabolites. Voles in the ALAN treatment showed higher activity at night during half moon, and had larger day ranges during new moon. Thus, even low levels of light pollution as experienced in remote areas or by sky glow can lead to changes in animal behavior and could have consequences for species interactions. Copyright © 2018 Elsevier Ltd. All rights reserved.

Night airglow in RGB mode

Directory of Open Access Journals (Sweden)

Mikhalev А.V.

2016-09-01

Full Text Available To study dynamics of the upper atmosphere, we consider results of the night sky photometry, using a color CCD camera and taking into account the night airglow and features of its spectral composition. We use night airglow observations for 2010–2015, which have been obtained at the ISTP SB RAS Geophysical Observatory (52° N, 103° E by the camera with KODAK KAI-11002 CCD sensor. We estimate average brightness of the night sky in R, G, B channels of the color camera for eastern Siberia with typical values ranging from ~0.008 to 0.01 erg·cm–2·s–1. Besides, we determine seasonal variations in the night sky luminosities in R, G, B channels of the color camera. In these channels, luminosities decrease in spring, increase in autumn, and have a pronounced summer maximum, which can be explained by scattered light and is associated with the location of the Geophysical Observatory. We consider geophysical phenomena with their optical effects in R, G, B channels of the color camera. For some geophysical phenomena (geomagnetic storms, sudden stratospheric warmings, we demonstrate the possibility of quantitative relationship between enhanced signals in R and G channels and increases in intensities of discrete 557.7 and 630 nm emissions, which are predominant in the airglow spectrum

[Shift and night work and mental health].

Science.gov (United States)

Sancini, Angela; Ciarrocca, Manuela; Capozzella, Assunta; Corbosiero, Paola; Fiaschetti, Maria; Caciari, Tiziana; Cetica, Carlotta; Scimitto, Lara; Ponticiello, Barnaba Giuseppina; Tasciotti, Zaira; Schifano, Maria Pia; Andreozzit, Giorgia; Tomei, Francesco; Tomei, Gianfranco

2012-01-01

Aim of our study was to evaluate the influence that shift work and night work could have on mental health. A review of literary articles from 1990 to 2011 on shift work and night work was carried out. The results of this review confirmed that the shift work and night work affect mental health with the onset of neuropsychological disorders such as mood disorders, anxiety, nervousness, depressive anxiety syndromes, chronic fatigue and chronic insomnia irritability, sleep disturbances, reduction in levels of attention, cognitive impairments, alteration of circadian rhythm. Night work and shift work cause severe desynchronization of the cronobiological rhythms and a disruption of social life with negative effects on performance at work, on health and on social relationships. In the light of these results and recognizing shift work and night work as risk factors for the health of workers is necessary to implement preventive and periodic health checks by the occupational doctor to ensure the health and safety of workers taking account of the different environmental and individual factors.

Light and colours

DEFF Research Database (Denmark)

Volf, Carlo

2011-01-01

Often a dichotomy between daylight and artificial light is observed, often artificial lighting replaces daylight. In Denmark daylight is characterized partly by being "borrowed" half of the year, partly by having long transitions periods between the light and the dark (nautical and civil twilight......). For these reasons artificial lighting does not complement daylight but provides, coupled with the daylight, the total lighting in the indoor environment. Electric lighting is therefore ‐ in a complex interaction with the daylight ‐ of great importance for both our lighting and our wellbeing. Studying artificial...... lighting without studying daylight seem to be a common procedure of the practice of today in Denmark and other parts of the industrialized world. As a consequence of this artificial lighting suffers from a quantifying tyranny, a tyranny where the quality of light is measured in quantities. This procedure...

Smart street lighting solution for remote rural areas of India

Science.gov (United States)

Hajra, Debdyut

2017-09-01

Though many smart street lighting solutions is available for urban areas, comparatively fewer solutions exist for rural areas. In the recent times, village streets have been illuminated with artificial lights as a part of rural development drive undertaken by the governments of respective countries. But, vehicle and pedestrian traffic is quite low through village roads. Hence, if light remains on all night long on such roads, then there is a huge wastage of energy. This calls for solutions to reduce this energy loss in an efficient manner. There are a lot of factors which must be kept in mind while designing solutions. Many villages lack the proper infrastructure to support new technologies. Communication facilities are limited, lack of local technically skilled labor, lack of security, etc. After evaluating these opportunities and challenges, an attempt has been made to devise a smart street lighting solution tailored for remote rural areas in India. One part of the solution discusses how intensity of the LED street lights can be varied according to the ambient lighting conditions using sensors and LED switching in LED matrix. An artificial intelligence (AI) has also been modelled to identify traffic conditions using PIR sensors and object identification through image processing and independently control the lights. It also tracks the performance and status of each light. It would send this data and necessary notifications to a distant control center for human evaluation. This solution is also applicable for other rural areas throughout the world.

GLOBE at Night: Raising Public Awareness and Involvement through Citizen Science

Science.gov (United States)

Walker, C. E.; Pompea, S. M.; Sparks, R. T.

2010-12-01

With half of the world’s population now living in cities, many urban dwellers have never experienced the wonderment of pristinely dark skies and maybe never will. Light pollution is obscuring people’s long-standing natural heritage to view stars. The GLOBE at Night program (www.globeatnight.org) is an international citizen-science campaign to raise public awareness of the impact of light pollution by encouraging everyone everywhere to measure local levels of night sky brightness and contribute observations online to a world map. In the last 5 years, GLOBE at Night has been the most productive public light pollution monitoring campaign, collecting over 52,000 observations in a two-week period annually. This year, during the moonless two weeks in March, the campaign set a record high of over 17,800 measurements from people in 86 countries. Foundational resources are available to facilitate the public’s participation in promoting dark skies awareness. The GLOBE at Night website explains clearly the simple-to-participate-in 5 step program and offers background information and interactive games on key concepts. The program has been expanded to include trainings of the general public, but especially educators in schools, museums and science centers, in unique ways. Education kits for dark skies awareness have been distributed at the training workshops. The kit includes material for a light shielding demonstration, a digital Sky Quality Meter and “Dark Skies Rangers” activities. The activities are on how unshielded light wastes energy, how light pollution affects wildlife and how you can participate in a citizen-science star-hunt like GLOBE at Night. In addition, projects are being developed for what to do with the data once it is taken. The GLOBE at Night data from different years can be compared to look for trends over time or with population density maps. The data can also be used to search for dark sky oases or to monitor lighting ordinance compliance. Most

Light sources and light pollution

International Nuclear Information System (INIS)

Pichler, G.

2005-01-01

From the dawn of mankind fire and light sources in general played an essential role in everyday life and protection over night. The development of new light sources went through many stages and is now an immense technological achievement, but also a threat for the wildlife at night, mainly because of the so-called light pollution. This paper discusses several very successful light sources connected with low pressure mercury and sodium vapour electric discharges. The luminous efficacy, colour rendering index and other lighting features cannot be always satisfactory, but at least some of the features can be much better than those met by the standard tungsten filament bulbs. High-pressure metal-vapour discharge lamps definitely have a good colour rendering index and a relatively high luminosity. Different light sources with burners at high pressure are discussed, paying special attention to their spectrum. The paper investigates new trends in development through a number of examples with non-toxic elements and pulsed electric discharge, which may be good news in terms of clean environment and energy savings. Light emitting diodes have recently appeared as worthy competitors to conventional light sources. White LEDs have approached 100 lumen/Watt efficacy in laboratories. This suggests that in some not very distant future they could completely replace high-pressure lamps, at least in indoor lighting. The article speculates on new developments which combine trends in nano technology and material science. The paper concludes with light pollution in view of several recent observations of plant and animal life at night in the vicinity of strong light sources. Photo-induced changes at the cell level may completely alter the normal life of plants and animals.(author)

Extension of Light-Harvesting Ability of Photosynthetic Light-Harvesting Complex 2 (LH2) through Ultrafast Energy Transfer from Covalently Attached Artificial Chromophores.

Science.gov (United States)

Yoneda, Yusuke; Noji, Tomoyasu; Katayama, Tetsuro; Mizutani, Naoto; Komori, Daisuke; Nango, Mamoru; Miyasaka, Hiroshi; Itoh, Shigeru; Nagasawa, Yutaka; Dewa, Takehisa

2015-10-14

Introducing appropriate artificial components into natural biological systems could enrich the original functionality. To expand the available wavelength range of photosynthetic bacterial light-harvesting complex 2 (LH2 from Rhodopseudomonas acidophila 10050), artificial fluorescent dye (Alexa Fluor 647: A647) was covalently attached to N- and C-terminal Lys residues in LH2 α-polypeptides with a molar ratio of A647/LH2 ≃ 9/1. Fluorescence and transient absorption spectroscopies revealed that intracomplex energy transfer from A647 to intrinsic chromophores of LH2 (B850) occurs in a multiexponential manner, with time constants varying from 440 fs to 23 ps through direct and B800-mediated indirect pathways. Kinetic analyses suggested that B800 chromophores mediate faster energy transfer, and the mechanism was interpretable in terms of Förster theory. This study demonstrates that a simple attachment of external chromophores with a flexible linkage can enhance the light harvesting activity of LH2 without affecting inherent functions of energy transfer, and can achieve energy transfer in the subpicosecond range. Addition of external chromophores, thus, represents a useful methodology for construction of advanced hybrid light-harvesting systems that afford solar energy in the broad spectrum.

Light pollution affects nesting behavior of loggerhead turtles and predation risk of nests and hatchlings.

Science.gov (United States)

Silva, Elton; Marco, Adolfo; da Graça, Jesemine; Pérez, Héctor; Abella, Elena; Patino-Martinez, Juan; Martins, Samir; Almeida, Corrine

2017-08-01

The introduction of artificial light into wildlife habitats is a rapidly expanding aspect of global change, which has many negative impacts on a wide range of taxa. In this experimental study, which took place on a beach located on the island of Boa Vista (Cabo Verde), three types of artificial light were tested on nesting loggerhead sea turtles as well as on ghost crabs, which intensively predate on nests and hatchlings, to determine the effects they would produce on the behavior of both species. Over the course of 36days, female loggerheads and ghost crabs were studied under yellow, orange and red lights, with observations also being made on dark nights that served as a control treatment. During this period, the frequencies of nesting attempts, the time taken by turtles to complete each phase of the nesting process, and ghost crab abundance and behaviors were carefully recorded. 1146 loggerhead nesting attempts were observed and recorded during the experiments, and results showed a decrease in nesting attempts of at least 20% when artificial lighting was present. A significant decline in successful attempts was also observed within the central sections of the beach, which corresponded to those that received more light. This artificial lighting significantly increased the time that turtles spent on the nesting process and forced them to do more extensive beach crawls. Despite this, the presence of light had no apparent effect on the final selection of the nesting site. Yellow and orange lights significantly disrupted the sea finding behavior and turtles were often unable to orient themselves seaward under these color lights. Disoriented turtles were observed crawling in circuitous paths in front of the light source for several minutes. In addition, artificial lights had the potential to increase the number of ghost crabs present within the illuminated stretches of the beach. However, only yellow lighting produced a significant change on aggressive and prey

Measuring light spectrum as a main indicator of artificial sources quality

Directory of Open Access Journals (Sweden)

Piotr Dąbrowski

2015-05-01

Full Text Available Objective: To compare different artificial light sources in different places where plant breeding is conduced. Methods: Measurements were conducted outdoor, in room, in greenhouse, under four panels with light emitting diodes, in phytotron, in dark room with various light sources and inside Sanyo versatile environmental chamber. The measurements were made by using SpectraPen SP100 (PSI, Czech Republic device. Results: Our result showed that spectrum measured outdoor during sunny day had only one peak at the wavelength of 485 nm (ca. 60000 relative units. On cloudy day, the trend of light spectrum curve was similar, but with lower values. At room conditions, the curve was more flat than outdoor. Under greenhouse conditions, the curve was similar to that measured outdoor. A few additional peaks on the curve appeared by adding high pressure sodium lamp. There were changes of curve under LED panels. Conclusions: It must be underlined that the most similar spectrum curve to daylight light has incandescent bulb and this light source should be preferred as support of daylight in greenhouses and as main source in phytotrons. Using high pressure sodium lamp in greenhouses as support of daylight cause increase in the red/far-red ratio and occurrence of a new peak on spectrum curve. The new possibilities are creating by LED panels with red and blue diodes.

An Artificial Neural Network for Analyzing Overall Uniformity in Outdoor Lighting Systems

Directory of Open Access Journals (Sweden)

Antonio del Corte-Valiente

2017-02-01

Full Text Available Street lighting installations are an essential service for modern life due to their capability of creating a welcoming feeling at nighttime. Nevertheless, several studies have highlighted that it is possible to improve the quality of the light significantly improving the uniformity of the illuminance. The main difficulty arises when trying to improve some of the installation’s characteristics based only on statistical analysis of the light distribution. This paper presents a new algorithm that is able to obtain the overall illuminance uniformity in order to improve this sort of installations. To develop this algorithm it was necessary to perform a detailed study of all the elements which are part of street lighting installations. Because classification is one of the most important tasks in the application areas of artificial neural networks, we compared the performances of six types of training algorithms in a feed forward neural network for analyzing the overall uniformity in outdoor lighting systems. We found that the best algorithm that minimizes the error is “Levenberg-Marquardt back-propagation”, which approximates the desired output of the training pattern. By means of this kind of algorithm, it is possible to help to lighting professionals optimize the quality of street lighting installations.

Characterizing the zenithal night sky brightness in large territories: how many samples per square kilometre are needed?

Science.gov (United States)

Bará, Salvador

2018-01-01

A recurring question arises when trying to characterize, by means of measurements or theoretical calculations, the zenithal night sky brightness throughout a large territory: how many samples per square kilometre are needed? The optimum sampling distance should allow reconstructing, with sufficient accuracy, the continuous zenithal brightness map across the whole region, whilst at the same time avoiding unnecessary and redundant oversampling. This paper attempts to provide some tentative answers to this issue, using two complementary tools: the luminance structure function and the Nyquist-Shannon spatial sampling theorem. The analysis of several regions of the world, based on the data from the New world atlas of artificial night sky brightness, suggests that, as a rule of thumb, about one measurement per square kilometre could be sufficient for determining the zenithal night sky brightness of artificial origin at any point in a region to within ±0.1 magV arcsec-2 (in the root-mean-square sense) of its true value in the Johnson-Cousins V band. The exact reconstruction of the zenithal night sky brightness maps from samples taken at the Nyquist rate seems to be considerably more demanding.

Light

DEFF Research Database (Denmark)

Prescott, N.B.; Kristensen, Helle Halkjær; Wathes, C.M.

2004-01-01

This chapter presents the effect of artificial light environments (light levels, colour, photoperiod and flicker) on the welfare of broilers in terms of vision, behaviour, lameness and mortality......This chapter presents the effect of artificial light environments (light levels, colour, photoperiod and flicker) on the welfare of broilers in terms of vision, behaviour, lameness and mortality...

Artificial LED lighting enhances growth characteristics and total phenolic content of Ocimum basilicum, but variably affects transplant success

NARCIS (Netherlands)

Bantis, Filippos; Ouzounis, Theoharis; Radoglou, Kalliopi

2016-01-01

The morphological and phytochemical characteristics of two Ocimum basilicum cultivars (Lettuce Leaf, and Red Rubin-mountain Athos hybrid) under artificial lighting were investigated. Four LED light treatments [AP673L (high red and high red:far-red), G2 (high red and low red:far-red), AP67

Night sky luminance under clear sky conditions: Theory vs. experiment

International Nuclear Information System (INIS)

Kocifaj, Miroslav

2014-01-01

Sky glow is caused by both natural phenomena and factors of anthropogenic origin, and of the latter ground-based light sources are the most important contributors for they emit the spatially linked spectral radiant intensity distribution of artificial light sources, which are further modulated by local atmospheric optics and perceived as the diffuse light of a night sky. In other words, sky glow is closely related to a city's shape and pattern of luminaire distribution, in practical effect an almost arbitrary deployment of random orientation of heterogeneous electrical light sources. Thus the luminance gradation function measured in a suburban zone or near the edges of a city is linked to the City Pattern or vice versa. It is shown that clear sky luminance/radiance data recorded in an urban area can be used to retrieve the bulk luminous/radiant intensity distribution if some a-priori information on atmospheric aerosols is available. For instance, the single scattering albedo of aerosol particles is required under low turbidity conditions, as demonstrated on a targeted experiment in the city of Frýdek-Mistek. One of the main advantages of the retrieval method presented in this paper is that the single scattering approximation is satisfactorily accurate in characterizing the light field near the ground because the dominant contribution to the sky glow has originated from beams propagated along short optical paths. - Highlights: • Urban sky glow is interpreted in terms of city emission function. • Luminance function in a suburban zone is linked to the City Pattern. • Single scattering approximation is applicable in modeling urban sky glow. • Information on aerosols represents valuable inputs to the retrieval procedure. • Sky glow patterns vary with light source distribution and spectral emission

Nocturnal light pollution and underexposure to daytime sunlight: Complementary mechanisms of circadian disruption and related diseases.

Science.gov (United States)

Smolensky, Michael H; Sackett-Lundeen, Linda L; Portaluppi, Francesco

2015-01-01

Routine exposure to artificial light at night (ALAN) in work, home, and community settings is linked with increased risk of breast and prostate cancer (BC, PC) in normally sighted women and men, the hypothesized biological rhythm mechanisms being frequent nocturnal melatonin synthesis suppression, circadian time structure (CTS) desynchronization, and sleep/wake cycle disruption with sleep deprivation. ALAN-induced perturbation of the CTS melatonin synchronizer signal is communicated maternally at the very onset of life and after birth via breast or artificial formula feedings. Nighttime use of personal computers, mobile phones, electronic tablets, televisions, and the like--now epidemic in adolescents and adults and highly prevalent in pre-school and school-aged children--is a new source of ALAN. However, ALAN exposure occurs concomitantly with almost complete absence of daytime sunlight, whose blue-violet (446-484 nm λ) spectrum synchronizes the CTS and whose UV-B (290-315 nm λ) spectrum stimulates vitamin D synthesis. Under natural conditions and clear skies, day/night and annual cycles of UV-B irradiation drive corresponding periodicities in vitamin D synthesis and numerous bioprocesses regulated by active metabolites augment and strengthen the biological time structure. Vitamin D insufficiency and deficiency are widespread in children and adults in developed and developing countries as a consequence of inadequate sunlight exposure. Past epidemiologic studies have focused either on exposure to too little daytime UV-B or too much ALAN, respectively, on vitamin D deficiency/insufficiency or melatonin suppression in relation to risk of cancer and other, e.g., psychiatric, hypertensive, cardiac, and vascular, so-called, diseases of civilization. The observed elevated incidence of medical conditions the two are alleged to influence through many complementary bioprocesses of cells, tissues, and organs led us to examine effects of the totality of the artificial light

Phase separation in artificial vesicles driven by light and curvature

Science.gov (United States)

Rinaldin, Melissa; Pomp, Wim; Schmidt, Thomas; Giomi, Luca; Kraft, Daniela; Physics of Life Processes Team; Soft; Bio Mechanics Collaboration; Self-Assembly in Soft Matter Systems Collaboration

The role of phase-demixing in living cells, leading to the lipid-raft hypothesis, has been extensively studied. Lipid domains of higher lipid chain order are proposed to regulate protein spatial organization. Giant Unilamellar Vesicles provide an artificial model to study phase separation. So far temperature was used to initiate the process. Here we introduce a new methodology based on the induction of phase separation by light. To this aim, the composition of the lipid membrane is varied by photo-oxidation of lipids. The control of the process gained by using light allowed us to observe vesicle shape fluctuations during phase-demixing. The presence of fluctuations near the critical mixing point resembles features of a critical process. We quantitatively analyze these fluctuations using a 2d elastic model, from which we can estimate the material parameters such as bending rigidity and surface tension, demonstrating the non-equilibrium critical behaviour. Finally, I will describe recent attempts toward tuning the membrane composition by controlling the vesicle curvature.

Low Cost Night Vision System for Intruder Detection

Science.gov (United States)

Ng, Liang S.; Yusoff, Wan Azhar Wan; R, Dhinesh; Sak, J. S.

2016-02-01

The growth in production of Android devices has resulted in greater functionalities as well as lower costs. This has made previously more expensive systems such as night vision affordable for more businesses and end users. We designed and implemented robust and low cost night vision systems based on red-green-blue (RGB) colour histogram for a static camera as well as a camera on an unmanned aerial vehicle (UAV), using OpenCV library on Intel compatible notebook computers, running Ubuntu Linux operating system, with less than 8GB of RAM. They were tested against human intruders under low light conditions (indoor, outdoor, night time) and were shown to have successfully detected the intruders.

Nocturnal feeding under artificial light conditions by Brown-hooded Gull (Larus maculipennis) in Puerto Madryn harbour (Chubut Province, Argentina)

NARCIS (Netherlands)

Leopold, M.F.; Philippart, C.J.M.; Yorio, P.

2010-01-01

This paper describes nocturnal, marine feeding behaviour in the Brown-hooded Gull (Larus maculipennis) in November 2009. The gulls assembled at night at the end of a long pier, running 800 m offshore into the Golfo Nuevo, at Puerto Madryn, Chubut Province, Argentina. Powerful lights predictably

Urban light pollution - The effect of atmospheric aerosols on astronomical observations at night

Science.gov (United States)

Joseph, Joachim H.; Mekler, Yuri; Kaufman, Yoram J.

1991-01-01

The transfer of diffuse city light from a localized source through a dust-laden atmosphere with optical depth less than 0.5 has been analyzed in the source-observer plane on the basis of an approximate treatment. The effect on several types of astronomical observation at night has been studied, considering different size distributions and amounts as well as particle shapes of the aerosols. The analysis is made in terms of the signal-to-noise ratios for a given amount of aerosol. The model is applied to conditions at the Wise Astronomical Observatory in the Negev desert, and limiting backgrounds for spectroscopy, photometry, and photography of stars and extended objects have been calculated for a variety of signal-to-noise ratios. Applications to observations with different equipment at various distances from an urban area of any size are possible. Due to the use of signal-to-noise ratios, the conclusions are different for the different experimental techniques used in astronomy.

Day-night contrast as source of health for the human circadian system.

Science.gov (United States)

Martinez-Nicolas, Antonio; Madrid, Juan Antonio; Rol, Maria Angeles

2014-04-01

Modern societies are characterized by a 24/7 lifestyle (LS) with no environmental differences between day and night, resulting in weak zeitgebers (weak day light, absence of darkness during night, constant environmental temperature, sedentary LS and frequent snacking), and as a consequence, in an impaired circadian system (CS) through a process known as chronodisruption. Both weak zeitgebers and CS impairment are related to human pathologies (certain cancers, metabolic syndrome and affective and cognitive disorders), but little is known about how to chronoenhance the CS. The aim of this work is to propose practical strategies for chronoenhancement, based on accentuating the day/night contrast. For this, 131 young subjects were recruited, and their wrist temperature (WT), activity, body position, light exposure, environmental temperature and sleep were recorded under free-living conditions for 1 week. Subjects with high contrast (HC) and low contrast (LC) for each variable were selected to analyze the HC effect in activity, body position, environmental temperature, light exposure and sleep would have on WT. We found that HC showed better rhythms than LC for every variable except sleep. Subjects with HC and LC for WT also demonstrated differences in LS, where HC subjects had a slightly advanced night phase onset and a general increase in day/night contrast. In addition, theoretical high day/night contrast calculated using mathematical models suggests an improvement by means of LS contrast. Finally, some individuals classified as belonging to the HC group in terms of WT when they are exposed to the LS characteristic of the LC group, while others exhibit WT arrhythmicity despite their good LS habits, revealing two different WT components: an exogenous component modified by LS and another endogenous component that is refractory to it. Therefore, intensifying day/night contrast in subject's LS has proven to be a feasible measure to chronoenhance the CS.

Measured energy savings from using night temperature setback

International Nuclear Information System (INIS)

Szydlowski, R.F.; Wrench, L.E.; O'Neill, P.J.

1993-01-01

The measured energy savings resulting from using night temperature setback in typical light-construction wooden office buildings was determined. Researchers installed monitoring equipment in a six-building sample of two-story wooden buildings at Fort Devens, Massachusetts. Data obtained during both single-setting and night-setback operating modes were used to develop models of each building's heat consumption as a function of the difference between inside and outside temperature. These models were used to estimate seasonal savings that could be obtained from the use of night-setback thermostat control. The measured savings in heating energy from using night temperature setback for the six Fort Devens buildings ranged from 14% to 25%; the mean savings was 19.2%. Based on an energy cost of $0.65/therm of natural gas, the estimated average cost savings of using automatic setback thermostats in these buildings is $780 per year per building

Effect of Cultural Practices in Night on Weed Density and Weed Dry Matter

Directory of Open Access Journals (Sweden)

M.H Rashed Mohasel

2011-01-01

Full Text Available Abstract In order to evaluate the response of weed seeds to light, two experiments, at two different locations were conducted at Ferdowsi university of Mashhad in 2009. At the first experiment, field was ploughed in day and night. Weed density was evaluated 70 d after plough, with 1×1 quadrate. At the second experiment, at night treatment, ploughing, potato planting and weeding with cultivator were done at night. Weed sampling was done twice at 43 and 130 days after planting with 1×1 quadrate and weeds were identified and counted. Result showed pigweed (Amaranthus retroflexus L., sowthistle (Sonchus oleraceus L., crabgrass (Digitaria sanguinalis (L. scop, jimsonweed (Datura stramonium L. and mallow (Hibiscus trionum L. did not observed at night plough, in contrast, night plough has no significance influence on common lambsquarters (Chenopodium album L., and black nightshade (Solanum nigrum L.. Only common lambsquarters had similar appearance in two treatments, indicating insusceptibility of this weed to time of plough. Interestingly, at the second experiment, result was very similar. Potato yield was higher at night treatment, but not significant. This research showed that some cultural practice like plough, planting and weeding with cultivator in night can reduce weed density and weed dry matter. Keywords: Germination, Time of plough, Sustainable weeds management, Light

What Astronomers and the AAS Need to be Doing to Curb Light Pollution

Science.gov (United States)

Green, D. W. E.

2001-12-01

Astronomers and especially the AAS are doing apalling little in the war on light pollution. This is quite surprising, considering that optical groundbased astronomy may become nearly extinct in the 21st century if we don't get more serious about the loss of our night skies to artificial lighting. Part of the blame must be placed on astronomers throughout the 20th century (particularly before 1980), as very few of them seem to have set an example by starting an early crusade against bad outdoor night lighting (save for a handful of important individuals near large U.S. observatories, and a few connected with smaller observatories); this apathy of earlier generations of astronomers fueled the current general apathy within the AAS and aided the opening of the floodgates in terms of the disastrous lighting situation now upon us in terms of drowning out the night sky. There are possible solutions, and they need to be discussed and acted upon quickly. For example, the AAS should require that all members include a useful amount (say, \\$30) in annual membership fees to be directly transmitted to the International Dark Sky Association, and the AAS should make constant visible strides to educate the public and government officials of the absolute need to reduce outdoor lighting levels and to fully shield all outdoor lighting. There are many other areas of research into outdoor lighting that the AAS should fund or officially/strongly support, so that the astronomical community can better be educated (and can better educate the public) on the evils of bad and thoughtless outdoor-lighting practices; such research includes developing a comprehensive database of national statistics on numbers and types of different outdoor lamps, as a function of time (thus, historical), and also a comprehensive database including all local, state, and federal lighting laws and ordinances together with legal court cases (and their outcomes) involving outdoor night lighting. And professional

Tuning the white light spectrum of light emitting diode lamps to reduce attraction of nocturnal arthropods.

Science.gov (United States)

Longcore, Travis; Aldern, Hannah L; Eggers, John F; Flores, Steve; Franco, Lesly; Hirshfield-Yamanishi, Eric; Petrinec, Laina N; Yan, Wilson A; Barroso, André M

2015-05-05

Artificial lighting allows humans to be active at night, but has many unintended consequences, including interference with ecological processes, disruption of circadian rhythms and increased exposure to insect vectors of diseases. Although ultraviolet and blue light are usually most attractive to arthropods, degree of attraction varies among orders. With a focus on future indoor lighting applications, we manipulated the spectrum of white lamps to investigate the influence of spectral composition on number of arthropods attracted. We compared numbers of arthropods captured at three customizable light-emitting diode (LED) lamps (3510, 2704 and 2728 K), two commercial LED lamps (2700 K), two commercial compact fluorescent lamps (CFLs; 2700 K) and a control. We configured the three custom LEDs to minimize invertebrate attraction based on published attraction curves for honeybees and moths. Lamps were placed with pan traps at an urban and two rural study sites in Los Angeles, California. For all invertebrate orders combined, our custom LED configurations were less attractive than the commercial LED lamps or CFLs of similar colour temperatures. Thus, adjusting spectral composition of white light to minimize attracting nocturnal arthropods is feasible; not all lights with the same colour temperature are equally attractive to arthropods. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

DETERMINATION OF THE LIGHT CURVE OF THE ARTIFICIAL SATELLITE BY ITS ROTATION PATH AS PREPARATION TO THE INVERSE PROBLEM SOLUTION

OpenAIRE

Pavlenko, Daniil

2012-01-01

Developing the algorithm of estimation of the rotational parameters of the artificial satellite by its light curve, we face the necessity to compute test light curves for various initially given types of rotation and specific features of lighting of the satellite. In the present study the algorithm of creation of such light curves with the simulation method and the obtained result are described.

Restless roosts

NARCIS (Netherlands)

Ouyang, Jenny Q.; Jong, de Maaike; Grunsven, van Roy H.A.; Matson, Kevin D.; Haussmann, Mark F.; Meerlo, Peter; Visser, Marcel E.; Spoelstra, Kamiel

2017-01-01

The natural nighttime environment is increasingly polluted by artificial light. Several studies have linked artificial light at night to negative impacts on human health. In free-living animals, light pollution is associated with changes in circadian, reproductive, and social behavior, but

Seeing the Night in a New Light—VIIRS Day/Night Band Capabilities and Prospects for a Joint Suomi/JPSS-1 Observing System

Science.gov (United States)

Solbrig, J. E.; Miller, S. D.; Straka, W. C.; Seaman, C.; Combs, C.; Heidinger, A.; Walther, A.

2017-12-01

The Day/Night Band (DNB), a special sensor on board the Visible/Infrared Imaging Radiometer Suite (VIIRS) devoted to low-light visible imaging, has representated a kind of `disruptive technology' in terms of how we observe the nocturnal environment. Since its debut on the Suomi National Polar-orbiting Partnership (NPP), launched in Fall 2011, the DNB has solidified its claim to fame as the most novel addition to the National Oceanic and Atmospheric Administration's future polar-oribitng program, represented by the Joint Polar Satellite System (JPSS). The first member of which (JPSS-1) is scheduled to launch in Fall of 2017, joining Suomi in its 1330 local time ascending node orbit. JPSS-1 will be displaced by ½ orbit ahead of Suomi, providing roughly 50 min between overpasses. Importantly, JPSS-1 will provide a second DNB observation, enabling the first time-resolved measurements of low-light visible at low and mid-latitudes from this new sensor technology. The DNB provides unprecedented capability to leverage light emissions from natural and artificial nocturnal sources, ranging from moonlight and city lights, ships, fires, lightning flashes, and even atmospheric nightglow. The calibrated DNB observations enable use of moonlight in similar way to daytime visible, allowing for quantitative description of cloud and aerosol optical properties. This presentation updates the community on DNB-related research initiatives. Statistics based on a multi-year collection of data at Salar de Uyuni, Bolivia and White Sands, New Mexico lend confidence to the performance of a lunar irradiance model used to enable nighttime optical property retrievals. Selected examples of notable events, including the devastating Portugal wildfires, emergence of the massive rift in the Larsen C ice shelf, and examples from the growing compilation of atmospheric gravity waves in nightglow, will also be highlighted.

Night-time activity forecast by season and weather in a longitudinal design - natural light effects on three years' rest-activity cycles in nursing home residents with dementia.

Science.gov (United States)

Wahnschaffe, Amely; Nowozin, Claudia; Rath, Andreas; Floessner, Theresa; Appelhoff, Stefan; Münch, Mirjam; Kunz, Dieter

2017-12-01

Backround: Night-time agitation is a frequent symptom of dementia. It often causes nursing home admission and has been linked to circadian rhythm disturbances. A positive influence of light interventions on night-time agitation was shown in several studies. The aim of our study was to investigate whether there is a long-term association between regional weather data (as indicator for daylight availability) and 24-hour variations of motor activity. Motor activity of 20 elderly nursing home residents living with dementia was analyzed using recordings of continuously worn wrist activity monitors over a three-year period. The average recording duration was 479 ± 206 days per participant (mean ± SD). Regional cloud amount and day length data from the local weather station (latitude: 52°56'N) were included in the analysis to investigate their effects on several activity variables. Nocturnal rest, here defined as the five consecutive hours with the least motor activity during 24 hours (L5), was the most predictable activity variable per participant. There was a significant interaction of night-time activity with day length and cloud amount (F 1,1174 = 4.39; p = 0.036). Night-time activity was higher on cloudy short days than on clear short days (p = 0.007), and it was also higher on cloudy short days than on cloudy long days (p = 0.032). The need for sufficient zeitgeber (time cue) strength during winter time, especially when days are short and skies are cloudy, is crucial for elderly people living with dementia. Activity forecast by season and weather might be a valuable approach to anticipate adequately complementary use of electrical light and thereby foster lower night-time activity.

Vineyard Yield Estimation Based on the Analysis of High Resolution Images Obtained with Artificial Illumination at Night

Directory of Open Access Journals (Sweden)

Davinia Font

2015-04-01

Full Text Available This paper presents a method for vineyard yield estimation based on the analysis of high-resolution images obtained with artificial illumination at night. First, this paper assesses different pixel-based segmentation methods in order to detect reddish grapes: threshold based, Mahalanobis distance, Bayesian classifier, linear color model segmentation and histogram segmentation, in order to obtain the best estimation of the area of the clusters of grapes in this illumination conditions. The color spaces tested were the original RGB and the Hue-Saturation-Value (HSV. The best segmentation method in the case of a non-occluded reddish table-grape variety was the threshold segmentation applied to the H layer, with an estimation error in the area of 13.55%, improved up to 10.01% by morphological filtering. Secondly, after segmentation, two procedures for yield estimation based on a previous calibration procedure have been proposed: (1 the number of pixels corresponding to a cluster of grapes is computed and converted directly into a yield estimate; and (2 the area of a cluster of grapes is converted into a volume by means of a solid of revolution, and this volume is converted into a yield estimate; the yield errors obtained were 16% and −17%, respectively.

Measuring the color and brightness of artificial sky glow from cities using an all-sky imaging system calibrated with astronomical methods in the Johnson-Cousins B and V photometric systems

Science.gov (United States)

Pipkin, Ashley; Duriscoe, Dan M.; Lughinbuhl, Christian

2017-01-01

Artificial light at night, when observed at some distance from a city, results in a dome of sky glow, brightest at the horizon. The spectral power distribution of electric light utilized will determine its color of the light dome and the amount of light will determine its brightness. Recent outdoor lighting technologies have included blue-rich light emitting diode (LED) sources that may increase the relative amount of blue to green light in sky glow compared to typical high pressure sodium (HPS) sources with warmer spectra. Measuring and monitoring this effect is important to the preservation of night sky visual quality as seen from undeveloped areas outside the city, such as parks or other protected areas, since the dark-adapted human eye is more sensitive to blue and green. We present a method using a wide field CCD camera which images the entire sky in both Johnson V and B photometric bands. Standard stars within the images are used for calibration. The resulting all-sky brightness maps, and a derived B-V color index map, provide a means to assess and track the impact of specific outdoor lighting practices. We also present example data from several cities, including Las Vegas, Nevada, Flagstaff, Arizona, and Cheyenne, Wyoming.

Effects of smartphone use with and without blue light at night in healthy adults: A randomized, double-blind, cross-over, placebo-controlled comparison.

Science.gov (United States)

Heo, Jung-Yoon; Kim, Kiwon; Fava, Maurizio; Mischoulon, David; Papakostas, George I; Kim, Min-Ji; Kim, Dong Jun; Chang, Kyung-Ah Judy; Oh, Yunhye; Yu, Bum-Hee; Jeon, Hong Jin

2017-04-01

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. Copyright © 2016 Elsevier Ltd. All rights reserved.

Short communication: Artificial ultraviolet B light exposure increases vitamin D levels in cow plasma and milk

DEFF Research Database (Denmark)

Jakobsen, Jette; Jensen, Søren Krogh; Hymøller, Lone

2015-01-01

tested the ability of a specially designed UVB lamp to enhance the vitamin D-3 content in milk from dairy cows housed indoors. This study included 16 cows divided into 4 groups. Each group was exposed daily to artificial UVB light simulating 1, 2, 3, or 4 h of summer sun at 56 degrees N for 24 d...... exposure to artificial UVB light to 73 d did not lead to an increase of vitamin D-3 or 25OHD(3) level in the milk. In conclusion, the change in production facilities for dairy cows providing cows with no access to pasture and sunlight causes a decrease of vitamin D levels in dairy products. This decrease......The number of dairy cows without access to pasture or sunlight is increasing; therefore, the content of vitamin D in dairy products is decreasing. Ultimately, declining vitamin D levels in dairy products will mean that dairy products are a negligible source of natural vitamin D for humans. We...

Communicating awareness of light pollution with the schools in Nepal

Science.gov (United States)

Acharya, Jayanta

2015-08-01

Nepal is also highly polluted by the lights and other dusts partials, but lacks the formal education of light pollutions and effect of light for astronomy observations. When we get Sky Quality Meter (SQM) last year (2014) we have installed it in Kathmandu.This paper will highlight about installation SQM in Nepal, measurement of brightness of the night sky in magnitudes per square arc second. Research work of light pollution of Kathmandu will be more in focus. Highlight of the Astronomy programs by different Schools in Nepal along with the background of coverage of Astronomy education in the syllables of different education level. The various procedure , technique and idea used in providing the space education through different activities and program to school studentsThe paper will also deal with the Importance of light and use of artificial light. Beside it will also highlight the possibility of development of various observatories in Nepal because of its tremendous topography increasing the Astro tourism in Nepal.Hence the paper would focus on the light pollution of the city like Kathmandu and light system in Nepal and Astronomy education to its implementation along with its outreach to Nepalese society.

Light pollution and solid-state lighting: reducing the carbon dioxide footprint is not enough

Science.gov (United States)

Bará, Salvador

2013-11-01

Public and private lighting account for a relevant share of the overall electric power consumption worldwide. The pressing need of reducing the carbon dioxide emissions as well as of lowering the lumen•hour price tag has fostered the search for alternative lighting technologies to substitute for the incandescent and gas-discharge based lamps. The most successful approach to date, solid-state lighting, is already finding its way into the public lighting market, very often helped by substantial public investments and support. LED-based sources have distinct advantages: under controlled coditions their efficacy equals or surpasses that of conventional solutions, their small source size allows for an efficient collimation of the lightbeam (delivering the photons where they are actually needed and reducing lightspill on the surrounding areas), and they can be switched and/or dimmed on demand at very high rates, thus allowing for a taylored schedule of lighting. However, energy savings and carbon dioxide reduction are not the only crucial issues faced by present day lighting. A growing body of research has shown the significance of the spectral composition of light when it comes to assess the detrimental effects of artificial light-at-night (ALAN). The potential ALAN blueshift associated to the deployment of LED-based lighting systems has raised sensible concerns about its scientific, cultural, ecological and public health consequences, which can be further amplified if an increased light consumption is produced due to the rebound effect. This contribution addresses some of the challenges that these issues pose to the Optics and Photonics community.

Porphyrin nanorods characterisation for an artificial light harvesting and energy transfer system

CSIR Research Space (South Africa)

Mongwaketsi, N

2010-01-01

Full Text Available s 1 0 h r s 1 3 h r s 1 5 h r s 1 8 h r s Porphyrin Nanorods Characterization for an Artificial Light Harvesting and Energy Transfer System Nametso Mongwaketsi1,2,3, Raymond Sparrow2, Bert Klumperman3, Malik Maaza1 1 NanoSciences Lab..., Materials Research Dept, iThemba LABS, PO Box 722, Somerset West, 7129, South Africa 2 CSIR Biosciences, PO Box 395, Pretoria, 0001, South Africa 3 Stellenbosch University, Department of Chemistry and Polymer Science, Private Bag X 1, Matieland, 7602...

VALIDITATION OF A LIGHT QUESTIONNAIRE WITH REAL-LIFE PHOTOPIC ILLUMINANCE MEASUREMENTS: THE HARVARD LIGHT EXPOSURE ASSESSMENT QUESTIONNAIRE

Science.gov (United States)

Bajaj, Archna; Rosner, Bernard; Lockley, Steven; Schernhammer, Eva S.

2011-01-01

Background Light exposure at night is now considered a probable carcinogen. To study the effects of light on chronic diseases like cancer, methods to measure light exposure in large observational studies are needed. We aimed to investigate the validity of self-reported current light exposure. Methods We developed a self-administered semiquantitative light questionnaire, the Harvard Light Exposure Assessment (H-LEA) questionnaire, and compared photopic scores derived from this questionnaire with actual photopic and circadian measures obtained from a real-life 7-day light meter application among 132 women (85 rotating night shift workers and 47 day workers) participating in the Nurses' Health Study II. Results After adjustment for age, BMI, collection day, and night work status, the overall partial Spearman correlation between self-report of light exposure and actual photopic light measurements was 0.72 (P<0.001; Kendall τ =0.57) and 0.73 (P<0.0001; Kendall τ =0.58) when correlating circadian light measurements. There were only minimal differences in accuracy of self-report of light exposure and photopic or circadian light measurement between day (r=0.77 and 0.78, respectively) and rotating night shift workers (r=0.68 and 0.69, respectively). Conclusions The results of this study provide evidence of the criterion validity of self-reported light exposure using the H-LEA questionnaire. Impact: This questionnaire is a practical method of assessing light exposure in large scale epidemiologic studies. PMID:21737411

Day and night shift schedules are associated with lower sleep quality in Evening-types.

Science.gov (United States)

Martin, Jeanne Sophie; Laberge, Luc; Sasseville, Alexandre; Bérubé, Marilie; Alain, Samuel; Houle, Jérôme; Hébert, Marc

2015-06-01

Eveningness has been suggested as a facilitating factor in adaptation to shift work, with several studies reporting evening chronotypes (E-types) as better sleepers when on night shifts. Conversely, eveningness has been associated with more sleep complaints during day shifts. However, sleep during day shifts has received limited attention in previous studies assessing chronotypes in shift workers. Environmental light exposure has also been reported to differ between chronotypes in day workers. Activity is also known to provide temporal input to the circadian clock. Therefore, the aim of this study was to compare objective sleep, light exposure and activity levels between chronotypes, both during the night and day shifts. Thirty-nine patrol police patrol officers working on a fast rotating shift schedule (mean age ± SD: 28.9 ± 3.2 yrs; 28 males) participated in this study. All subjects completed the Morningness-Eveningness Questionnaire (MEQ). Sleep and activity were monitored with actigraphy (Actiwatch-L; Mini-Mitter/Respironics, Bend, OR) for four consecutive night shifts and four consecutive day shifts (night work schedule: 00:00 h-07:00 h; day work schedule: 07:00 h-15:00 h). Sleep and activity parameters were calculated with Actiware software. MEQ scores ranged from 26 to 56; no subject was categorized as Morning-type. E-types (n = 13) showed significantly lower sleep efficiency, longer snooze time and spent more time awake after sleep onset than Intermediate-types (I-types, n = 26) for both the night and day shifts. E-types also exhibited shorter and more numerous sleep bouts. Furthermore, when napping was taken into account, E-types had shorter total sleep duration than I-types during the day shifts. E-types were more active during the first hours of their night shift when compared to I-types. Also, all participants spent more time active and had higher amount of activity per minute during day shifts when compared to night shifts. No

Sport Transition of JPSS VIIRS Imagery for Night-time Applications

Science.gov (United States)

Fuell, Kevin; LeRoy, Anita; Smith, Matt; Miller, Steve; Kann, Diedre; Bernhardt, David; Reydell, Nezette; Cox, Robert

2014-01-01

The NASA/Short-term Prediction, Research, and Transition (SPoRT) Program and NOAA/Cooperative Institute for Research in the Atmosphere (CIRA) work within the NOAA/Joint Polar Satellite System (JPSS) Proving Ground to demonstrate the unique capabilities of the VIIRS instrument. Very similar to MODIS, the VIIRS instrument provides many high-resolution visible and infrared channels in a broad spectrum. In addition, VIIRS is equipped with a low-light sensor that is able to detect light emissions from the land and atmosphere as well as reflected sunlight by the lunar surface. This band is referred to as the Day-Night Band due to the sunlight being used at night to see cloud and topographic features just as one would typically see in day-time visible imagery. NWS forecast offices that collaborate with SPoRT and CIRA have utilized MODIS imagery in operations, but have longed for more frequent passes of polar-orbiting data. The VIIRS instrument enhances SPoRT collaborations with WFOs by providing another day and night-time pass, and at times two additional passes due to its large swath width. This means that multi-spectral, RGB imagery composites are more readily available to prepare users for their use in GOES-R era and high-resolution imagery for use in high-latitudes is more frequently able to supplement standard GOES imagery within the SPoRT Hybrid GEO-LEO product. The transition of VIIRS also introduces the new Day-Night Band capability to forecast operations. An Intensive Evaluation Period (IEP) was conducted in Summer 2013 with a group of "Front Range" NWS offices related to VIIRS night-time imagery. VIIRS single-channel imagery is able to better analyze the specific location of fire hotspots and other land features, as well as provide a more true measurement of various cloud and aerosol properties than geostationary measurements, especially at night. Viewed within the SPoRT Hybrid imagery, the VIIRS data allows forecasters to better interpret the more frequent, but

Artificial Leaf Based on Artificial Photosynthesis for Solar Fuel Production

Science.gov (United States)

2017-06-30

collect light energy and separate charge for developing new types of nanobiodevices to construct ”artificial leaf” from solar to fuel. or Concept of...AFRL-AFOSR-JP-TR-2017-0054 Artificial Leaf Based on Artificial Photosynthesis for Solar Fuel Production Mamoru Nango NAGOYA INSTITUTE OF TECHNOLOGY...display a currently valid OMB control number. PLEASE DO NOT RETURN YOUR FORM TO THE ABOVE ORGANIZATION. 1. REPORT DATE (DD-MM-YYYY)      30-06-2017 2

Quantifying light pollution

International Nuclear Information System (INIS)

Cinzano, P.; Falchi, F.

2014-01-01

In this paper we review new available indicators useful to quantify and monitor light pollution, defined as the alteration of the natural quantity of light in the night environment due to introduction of manmade light. With the introduction of recent radiative transfer methods for the computation of light pollution propagation, several new indicators become available. These indicators represent a primary step in light pollution quantification, beyond the bare evaluation of the night sky brightness, which is an observational effect integrated along the line of sight and thus lacking the three-dimensional information. - Highlights: • We review new available indicators useful to quantify and monitor light pollution. • These indicators are a primary step in light pollution quantification. • These indicators allow to improve light pollution mapping from a 2D to a 3D grid. • These indicators allow carrying out a tomography of light pollution. • We show an application of this technique to an Italian region

Light pollution, reproductive function and cancer risk.

Science.gov (United States)

Anisimov, Vladimir N

2006-01-01

At present, light pollution (exposure to light-at-night) both in the form of occupational exposure during night work and as a personal choice and life style, is experienced by numerous night-active members of our society. Disruption of the circadian rhythms induced by light pollution has been associated with cancer in humans. There are epidemiological evidences of increased breast and colon cancer risk in shift workers. An inhibition of the pineal gland function with exposure to the constant light (LL) regimen promoted carcinogenesis whereas the light deprivation inhibits the carcinogenesis. Treatment with pineal indole hormone melatonin inhibits carcinogenesis in pinealectomized rats or animals kept at the standard light/dark regimen (LD) or at the LL regimen. These observations might lead to use melatonin for cancer prevention in groups of humans at risk of light pollution.

Genetics Home Reference: autosomal dominant congenital stationary night blindness

Science.gov (United States)

... collapse boxes. Description Autosomal dominant congenital stationary night blindness is a disorder of the retina , which is the specialized tissue at the back of the eye that detects light and color. People with this condition typically have difficulty seeing ...

Genetics Home Reference: X-linked congenital stationary night blindness

Science.gov (United States)

... collapse boxes. Description X-linked congenital stationary night blindness is a disorder of the retina , which is the specialized tissue at the back of the eye that detects light and color. People with this condition typically have difficulty seeing ...

Genetics Home Reference: autosomal recessive congenital stationary night blindness

Science.gov (United States)

... collapse boxes. Description Autosomal recessive congenital stationary night blindness is a disorder of the retina , which is the specialized tissue at the back of the eye that detects light and color. People with this condition typically have difficulty seeing ...

Using DMSP-OLS Night Light Data for Proxying and Comparing Regional Development in Russia and China, 1992-2012

Science.gov (United States)

Bennett, M.; Smith, L. C.

2016-12-01

To date, no studies have examined the transition from communism to capitalism in Russia or China with night light (NTL) data despite the availability of DMSP-OLS satellite imagery dating back to 1992, one year after the dissolution of the Soviet Union. This paper uses the DMSP-OLS Version 4 stable lights annual image composites for every year from 1992-2012 to reveal the complex and sometimes divergent trajectories of regional development in Russia and China. We first characterize the spatial patterns and characteristics of NTL intensity and extensivity in Russia versus China at national and regional scales across this 21-year period. Although GDP rises in both countries during this time, NTL tells a different story: total night light (tNTL) in Russia in 2012 is slightly lower than in 1992, while tNTL in China is significantly higher. Next, we generate regional-level tNTL from each annual composite and examine their relationships with population, GDP, and fixed capital investment data from the Russian Federal State Statistics Service and the National Bureau of Statistics of China using a fixed effects model. We determine that while the fixed effects "between" model explains more of the differences in tNTL between Russia's federal subjects, the "within" model better explains differences over time within China's provinces. This suggests that on the one hand, Russia's regions are more heterogeneous than China's. On the other hand, whereas change over time in population and GRP explains change over time in tNTL in China's regions, they hardly do so at all for Russia's. Finally, we attempt to combine these socioeconomic variables with NTL data to build an NTL-based typology of regional development, representing a step beyond existing research. The preliminary creation of a regional development typology allows us to begin identifying emerging resource frontiers (places with increases in NTL but decreases in population) along with areas experiencing a reversal of

Recognizing pedestrian's unsafe behaviors in far-infrared imagery at night

Science.gov (United States)

Lee, Eun Ju; Ko, Byoung Chul; Nam, Jae-Yeal

2016-05-01

Pedestrian behavior recognition is important work for early accident prevention in advanced driver assistance system (ADAS). In particular, because most pedestrian-vehicle crashes are occurred from late of night to early of dawn, our study focus on recognizing unsafe behavior of pedestrians using thermal image captured from moving vehicle at night. For recognizing unsafe behavior, this study uses convolutional neural network (CNN) which shows high quality of recognition performance. However, because traditional CNN requires the very expensive training time and memory, we design the light CNN consisted of two convolutional layers and two subsampling layers for real-time processing of vehicle applications. In addition, we combine light CNN with boosted random forest (Boosted RF) classifier so that the output of CNN is not fully connected with the classifier but randomly connected with Boosted random forest. We named this CNN as randomly connected CNN (RC-CNN). The proposed method was successfully applied to the pedestrian unsafe behavior (PUB) dataset captured from far-infrared camera at night and its behavior recognition accuracy is confirmed to be higher than that of some algorithms related to CNNs, with a shorter processing time.

Artificial Intelligence in Astronomy

Science.gov (United States)

Devinney, E. J.; Prša, A.; Guinan, E. F.; Degeorge, M.

2010-12-01

From the perspective (and bias) as Eclipsing Binary researchers, we give a brief overview of the development of Artificial Intelligence (AI) applications, describe major application areas of AI in astronomy, and illustrate the power of an AI approach in an application developed under the EBAI (Eclipsing Binaries via Artificial Intelligence) project, which employs Artificial Neural Network technology for estimating light curve solution parameters of eclipsing binary systems.

OLED-based physiologically-friendly very low-color temperature illumination for night

Science.gov (United States)

Jou, Jwo-Huei; Shen, Shih-Ming; Tang, Ming-Chun; Chen, Pin-Chu; Chen, Szu-Hao; Wang, Yi-Shan; Chen, Chien-Chih; Wang, Ching-Chun; Hsieh, Chun-Yu; Lin, Chin-Chiao; Chen, Chien-Tien

2012-09-01

Numerous medical research studies reveal intense white or blue light to drastically suppress at night the secretion of melatonin (MLT), a protective oncostatic hormone. Lighting devices with lower color-temperature (CT) possess lesser MLT suppression effect based on the same luminance, explaining why physicians have long been calling for the development of lighting sources with low CT or free from blue emission for use at night to safeguard human health. We will demonstrate in the presentation the fabrication of OLED devices with very-low CT, especially those with CT much lower than that of incandescent bulbs (2500K) or even candles (2000K). Without any light extraction method, OLEDs with an around 1800K CT are easily obtainable with an efficacy of 30 lm/W at 1,000 nits. To also ensure high color-rendering to provide visual comfort, low CT OLEDs composing long wavelength dominant 5-spectrum emission have been fabricated. While keeping the color-rendering index as high as 85 and CT as low as 2100K, the resulting efficacy can also be much greater than that of incandescent bulbs (15 lm/W), proving these low CT OLED devices to be also capable of being energy-saving and high quality. The color-temperature can be further decreased to 1700K or lower upon removing the undesired short wavelength emission but on the cost of losing some color rendering index. It is hoped that the devised energy-saving, high quality low CT OLED could properly echo the call for a physiologically-friendly illumination for night, and more attention could be drawn to the development of MLT suppression-less non-white light.

The Experience of Dynamic Lighting

DEFF Research Database (Denmark)

Petersen, Kjell Yngve; Kristensen, Ole

2017-01-01

of daylight openings and the experience of spatial form. However, current developments in LED light sources (light emitting diodes) and adaptive software control systems allow for an enhanced correlation between daylight and artificial lighting, where the variations of the daylight are dynamically...... supplemented by variations in the artificial lighting. The suggestion is to develop a particular type of Observational Instrument that situates detailed experiential investigations into the design potentials of integration of natural and artificial lighting, and thereby to enable differentiated dynamic...

Artificial light pollution: Shifting spectral wavelengths to mitigate physiological and health consequences in a nocturnal marsupial mammal.

Science.gov (United States)

Dimovski, Alicia M; Robert, Kylie A

2018-05-02

The focus of sustainable lighting tends to be on reduced CO 2 emissions and cost savings, but not on the wider environmental effects. Ironically, the introduction of energy-efficient lighting, such as light emitting diodes (LEDs), may be having a great impact on the health of wildlife. These white LEDs are generated with a high content of short-wavelength 'blue' light. While light of any kind can suppress melatonin and the physiological processes it regulates, these short wavelengths are potent suppressors of melatonin. Here, we manipulated the spectral composition of LED lights and tested their capacity to mitigate the physiological and health consequences associated with their use. We experimentally investigated the impact of white LEDs (peak wavelength 448 nm; mean irradiance 2.87 W/m 2 ), long-wavelength shifted amber LEDs (peak wavelength 605 nm; mean irradiance 2.00 W/m 2 ), and no lighting (irradiance from sky glow light treatments. White LED exposed wallabies had significantly suppressed nocturnal melatonin compared to no light and amber LED exposed wallabies, while there was no difference in lipid peroxidation. Antioxidant capacity declined from baseline to week 10 under all treatments. These results provide further evidence that short-wavelength light at night is a potent suppressor of nocturnal melatonin. Importantly, we also illustrate that shifting the spectral output to longer wavelengths could mitigate these negative physiological impacts. © 2018 Wiley Periodicals, Inc.

Night Sky Brightness Measurement by the Public through a Mobile Phone App

Science.gov (United States)

Kamegai, Kazuhisa; Tsukada, Ken; Inoue, Hiroki

2015-08-01

The darkness of night sky is important naturally for astronomy researchers, and also for the public people. Particularly, it is meaningful for those who begin to have an interest in gazing stars. Some previous studies suggest that light pollution may affect human health and ecosystem in various ways. Furthermore, it causes a lot of waste of electric energy for lighting.In Japan, the night sky brightness had been measured by Ministry of Environment for a few decades. Recently some global efforts have been also conducted. However the number of measured position is limited because the measurement needs some apparatus and takes long time.Here we show a result of quick and easy measurements of night sky brightness by the public people through a mobile phone app. The measurements were conducted in cooperation between some members of the Tenpla project and a weather forecasting company. The app has been developed by the company and has been installed by over 6.5 million people, which allow us to get a large number of data. Our purposes are (1) making map of night sky brightness all over Japan and (2) providing an opportunity to enjoy gazing star for those who are not usually interested in astronomy.As an interactive function of the app, we put a questionnaire of four choices in which we ask users how many stars are visible in a part of the constellation of Orion. When users answer the question, we get the answer and the position where they are. Depending on the answer, we can roughly recognize the sky brightness of the position.We opened the measurements for several nights. As a result, we could get 4000 - 5000 data all over the country per night. The map of each night is a snapshot of sky brightness of the night including effect of the weather. For example we can recognize that the sky is getting darker as a function of distance from the metropolitan area of Tokyo. We will show the detail results in the presentation.

Assessment and the feasibility of improving the artificial lighting system in technical services workshop located in the Fourth South Pars Gas Refinery

OpenAIRE

masoud shafiee motlagh; Mohsen Aliabadi; Reza Shahidi; Amin Kahani

2015-01-01

Background & Objectives: Desirable and ergonomic lighting in the workplaces has a significant impact on the visual effects and improve the efficiency and productivity of employees. This study aims to evaluate the lighting system and feasibility of improving the artificial lighting system for comfort lighting in the workshop of the Fourth South Pars Gas Refinery. Methods: In this descriptive-analytical study, the environmental conditions of the studied workshop were evaluated and the illum...

Students' educational experiences and interaction with residents on night shifts.

Science.gov (United States)

Schiller, Jocelyn; Sokoloff, Max; Tendhar, Chosang; Schmidt, John; Christner, Jennifer

2017-08-01

The purpose of this mixed-methods study was to investigate whether increased night shifts for students on paediatric rotations had any negative impact on their overall quality of educational experiences in light of the implementation of duty-hour restrictions. Both quantitative and qualitative data were collected from 30 students on paediatric rotations during the academic year 2011/12. Students completed two questionnaires, one in response to their experiences during the day shifts and another in response to their experiences during the night shifts. Only 25 cases were retained for the final analyses. The non-parametric Wilcoxon signed-rank test was used to analyse the quantitative data, and constant comparative thematic analyses, as described by Creswell, were used to analyse the qualitative data. [Do] increased nights shifts for students … [have] any negative impact on their overall quality of educational experiences[?] RESULTS: The results indicated that students' perceived quality of experiences during the night shifts was greater, compared with their day shifts. Students reported having more time to socialise during the night shifts. They further reported that informal ways of learning, such as impromptu teaching and spontaneous discussions on clinical problems, were more beneficial, and these often occurred in abundance during the night shifts as opposed to the scheduled didactic teaching sessions that occur during the day shifts. This study documented many unanticipated benefits of night shifts. The feeling of cohesiveness of the night team deserves further exploration, as this can be linked to better performance outcomes. More consideration should be given to implementing night shifts as a regular feature of clerkships. © 2016 John Wiley & Sons Ltd and The Association for the Study of Medical Education.

GPS tracking for mapping seabird mortality induced by light pollution.

Science.gov (United States)

Rodríguez, Airam; Rodríguez, Beneharo; Negro, Juan J

2015-06-02

Light pollution and its consequences on ecosystems are increasing worldwide. Knowledge on the threshold levels of light pollution at which significant ecological impacts emerge and the size of dark refuges to maintain natural nocturnal processes is crucial to mitigate its negative consequences. Seabird fledglings are attracted by artificial lights when they leave their nest at night, causing high mortality. We used GPS data-loggers to track the flights of Cory's shearwater Calonectris diomedea fledglings from nest-burrows to ground, and to evaluate the light pollution levels of overflown areas on Tenerife, Canary Islands, using nocturnal, high-resolution satellite imagery. Birds were grounded at locations closer than 16 km from colonies in their maiden flights, and 50% were rescued within a 3 km radius from the nest-site. Most birds left the nests in the first three hours after sunset. Rescue locations showed radiance values greater than colonies, and flight distance was positively related to light pollution levels. Breeding habitat alteration by light pollution was more severe for inland colonies. We provide scientific-based information to manage dark refuges facilitating that fledglings from inland colonies reach the sea successfully. We also offer methodological approaches useful for other critically threatened petrel species grounded by light pollution.

Night Shift Work and Risk of Breast Cancer.

Science.gov (United States)

Hansen, Johnni

2017-09-01

Night work is increasingly common and a necessity in certain sectors of the modern 24-h society. The embedded exposure to light-at-night, which suppresses the nocturnal hormone melatonin with oncostatic properties and circadian disruption, i.e., misalignment between internal and external night and between cells and organs, are suggested as main mechanisms involved in carcinogenesis. In 2007, the International Agency for Research on Cancer (IARC) classified shift work that involves circadian disruption as probably carcinogenic to humans based on limited evidence from eight epidemiologic studies on breast cancer, in addition to sufficient evidence from animal experiments. The aim of this review is a critical update of the IARC evaluation, including subsequent and the most recent epidemiologic evidence on breast cancer risk after night work. After 2007, in total nine new case-control studies, one case-cohort study, and eight cohort studies are published, which triples the number of studies. Further, two previous cohorts have been updated with extended follow-up. The assessment of night shift work is different in all of the 26 existing studies. There is some evidence that high number of consecutive night shifts has impact on the extent of circadian disruption, and thereby increased breast cancer risk, but this information is missing in almost all cohort studies. This in combination with short-term follow-up of aging cohorts may explain why some cohort studies may have null findings. The more recent case-control studies have contributed interesting results concerning breast cancer subtypes in relation to both menopausal status and different hormonal subtypes. The large differences in definitions of both exposure and outcome may contribute to the observed heterogeneity of results from studies of night work and breast cancer, which overall points in the direction of an increased breast cancer risk, in particular after over 20 years of night shifts. Overall, there is a

The effect of bright light on sleepiness among rapid-rotating 12-hour shift workers.

Science.gov (United States)

Sadeghniiat-Haghighi, Khosro; Yazdi, Zohreh; Jahanihashemi, Hassan; Aminian, Omid

2011-01-01

About 20% of workers in industrialized countries are shift workers and more than half of them work on night or rotating shifts. Most night workers complain of sleepiness due to lack of adjustment of the circadian rhythm. In simulated night-work experiments, scheduled exposure to bright light has been shown to reduce these complaints. Our study assessed the effects of bright light exposure on sleepiness during night work in an industrial setting. In a cross-over design, 94 workers at a ceramic factory were exposed to either bright (2500 lux) or normal light (300 lux) during breaks on night shifts. We initiated 20-minute breaks between 24.00 and 02.00 hours. Sleepiness ratings were determined using the Stanford Sleepiness Scale at 22.00, 24.00, 02.00 and 04.00 hours. Under normal light conditions, sleepiness peaked at 02:00 hours. A significant reduction (22% compared to normal light conditions) in sleepiness was observed after workers were exposed to bright light. Exposure to bright light may be effective in reducing sleepiness among night workers.

Preliminary evidence for a change in spectral sensitivity of the circadian system at night

Directory of Open Access Journals (Sweden)

Parsons Robert H

2005-12-01

Full Text Available Abstract Background It is well established that the absolute sensitivity of the suprachiasmatic nucleus to photic stimulation received through the retino-hypothalamic tract changes throughout the 24-hour day. It is also believed that a combination of classical photoreceptors (rods and cones and melanopsin-containing retinal ganglion cells participate in circadian phototransduction, with a spectral sensitivity peaking between 440 and 500 nm. It is still unknown, however, whether the spectral sensitivity of the circadian system also changes throughout the solar day. Reported here is a new study that was designed to determine whether the spectral sensitivity of the circadian retinal phototransduction mechanism, measured through melatonin suppression and iris constriction, varies at night. Methods Human adult males were exposed to a high-pressure mercury lamp [450 lux (170 μW/cm2 at the cornea] and an array of blue light emitting diodes [18 lux (29 μW/cm2 at the cornea] during two nighttime experimental sessions. Both melatonin suppression and iris constriction were measured during and after a one-hour light exposure just after midnight and just before dawn. Results An increase in the percentage of melatonin suppression and an increase in pupil constriction for the mercury source relative to the blue light source at night were found, suggesting a temporal change in the contribution of photoreceptor mechanisms leading to melatonin suppression and, possibly, iris constriction by light in humans. Conclusion The preliminary data presented here suggest a change in the spectral sensitivity of circadian phototransduction mechanisms at two different times of the night. These findings are hypothesized to be the result of a change in the sensitivity of the melanopsin-expressing retinal ganglion cells to light during the night.

Light exposure at night disrupts host/cancer circadian regulatory dynamics: impact on the Warburg effect, lipid signaling and tumor growth prevention.

Directory of Open Access Journals (Sweden)

David E Blask

Full Text Available The central circadian clock within the suprachiasmatic nucleus (SCN plays an important role in temporally organizing and coordinating many of the processes governing cancer cell proliferation and tumor growth in synchrony with the daily light/dark cycle which may contribute to endogenous cancer prevention. Bioenergetic substrates and molecular intermediates required for building tumor biomass each day are derived from both aerobic glycolysis (Warburg effect and lipid metabolism. Using tissue-isolated human breast cancer xenografts grown in nude rats, we determined that circulating systemic factors in the host and the Warburg effect, linoleic acid uptake/metabolism and growth signaling activities in the tumor are dynamically regulated, coordinated and integrated within circadian time structure over a 24-hour light/dark cycle by SCN-driven nocturnal pineal production of the anticancer hormone melatonin. Dim light at night (LAN-induced melatonin suppression disrupts this circadian-regulated host/cancer balance among several important cancer preventative signaling mechanisms, leading to hyperglycemia and hyperinsulinemia in the host and runaway aerobic glycolysis, lipid signaling and proliferative activity in the tumor.

Night-to-night arousal variability and interscorer reliability of arousal measurements.

Science.gov (United States)

Loredo, J S; Clausen, J L; Ancoli-Israel, S; Dimsdale, J E

1999-11-01

Measurement of arousals from sleep is clinically important, however, their definition is not well standardized, and little data exist on reliability. The purpose of this study is to determine factors that affect arousal scoring reliability and night-to-night arousal variability. The night-to-night arousal variability and interscorer reliability was assessed in 20 subjects with and without obstructive sleep apnea undergoing attended polysomnography during two consecutive nights. Five definitions of arousal were studied, assessing duration of electroencephalographic (EEG) frequency changes, increases in electromyographic (EMG) activity and leg movement, association with respiratory events, as well as the American Sleep Disorders Association (ASDA) definition of arousals. NA. NA. NA. Interscorer reliability varied with the definition of arousal and ranged from an Intraclass correlation (ICC) of 0.19 to 0.92. Arousals that included increases in EMG activity or leg movement had the greatest reliability, especially when associated with respiratory events (ICC 0.76 to 0.92). The ASDA arousal definition had high interscorer reliability (ICC 0.84). Reliability was lowest for arousals consisting of EEG changes lasting <3 seconds (ICC 0.19 to 0.37). The within subjects night-to-night arousal variability was low for all arousal definitions In a heterogeneous population, interscorer arousal reliability is enhanced by increases in EMG activity, leg movements, and respiratory events and decreased by short duration EEG arousals. The arousal index night-to-night variability was low for all definitions.

Lighting in the urban context case study: Exterior decorative lighting of St. Marko's Church in Belgrade

Directory of Open Access Journals (Sweden)

Đokić Lidija

2006-01-01

Full Text Available In the past few years more attention has been devoted to exterior decorative lighting in Belgrade. Unfortunately, illuminance is very often the only quality factor for lighting design. Lighting quality is a broader concept than illuminance (quantity of light, determined by a number of factors out of which some can and others cannot be quantitatively determined. Buildings and spaces with urban, architectural and/or style values impose certain requests for lighting design, which can either emphasize or degrade these values. The lighting designer has the obligation to respond to the imposed requests and in this way support the building concept, as well as its role in the urban context. Various possibilities of artificial lighting enable better, more effective and more interesting impressions of buildings than experienced in daylight conditions. Some of the significant possibilities of artificial lighting, which can satisfy requests imposed by urban architectural or style elements, include: The possibility to emphasize elements of style, building details or ornaments, which resemble the most important values on a building or façade. This enables elements of exceptional value to be clearly noticeable (in a greater extent than in daylight conditions; Decorative lighting allows the possibility of presenting the hierarchy of architectural or style elements, which is a contribution to the emphasis of the main idea and building spirit; ® The possibility to emphasize proportions and/or balance of the façade, making solids and voids clearly distinctive; If emphasis of the building concept is the lighting aim, it is possible to realize different impressions from the ones experienced in daylighting (lighting the facade plane which is drawn in and remains in the shadow during the day; When lighting modern architecture, decorative lighting has the possibility to promote the main idea, emphasizing proportions, valuable building parts and/or the rhythm of the

Quantitative analysis of night skyglow amplification under cloudy conditions

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Kocifaj, Miroslav; Solano Lamphar, Héctor Antonio

2014-10-01

The radiance produced by artificial light is a major source of nighttime over-illumination. It can, however, be treated experimentally using ground-based and satellite data. These two types of data complement each other and together have a high information content. For instance, the satellite data enable upward light emissions to be normalized, and this in turn allows skyglow levels at the ground to be modelled under cloudy or overcast conditions. Excessive night lighting imposes an unacceptable burden on nature, humans and professional astronomy. For this reason, there is a pressing need to determine the total amount of downwelling diffuse radiation. Undoubtedly, cloudy periods can cause a significant increase in skyglow as a result of amplification owing to diffuse reflection from clouds. While it is recognized that the amplification factor (AF) varies with cloud cover, the effects of different types of clouds, of atmospheric turbidity and of the geometrical relationships between the positions of an individual observer, the cloud layer, and the light source are in general poorly known. In this paper the AF is quantitatively analysed considering different aerosol optical depths (AODs), urban layout sizes and cloud types with specific albedos and altitudes. The computational results show that the AF peaks near the edges of a city rather than at its centre. In addition, the AF appears to be a decreasing function of AOD, which is particularly important when modelling the skyglow in regions with apparent temporal or seasonal variability of atmospheric turbidity. The findings in this paper will be useful to those designing engineering applications or modelling light pollution, as well as to astronomers and environmental scientists who aim to predict the amplification of skyglow caused by clouds. In addition, the semi-analytical formulae can be used to estimate the AF levels, especially in densely populated metropolitan regions for which detailed computations may be CPU

Effects of weather conditions, light conditions, and road lighting on vehicle speed.

Science.gov (United States)

Jägerbrand, Annika K; Sjöbergh, Jonas

2016-01-01

Light conditions are known to affect the number of vehicle accidents and fatalities but the relationship between light conditions and vehicle speed is not fully understood. This study examined whether vehicle speed on roads is higher in daylight and under road lighting than in darkness, and determined the combined effects of light conditions, posted speed limit and weather conditions on driving speed. The vehicle speed of passenger cars in different light conditions (daylight, twilight, darkness, artificial light) and different weather conditions (clear weather, rain, snow) was determined using traffic and weather data collected on an hourly basis for approximately 2 years (1 September 2012-31 May 2014) at 25 locations in Sweden (17 with road lighting and eight without). In total, the data included almost 60 million vehicle passes. The data were cleaned by removing June, July, and August, which have different traffic patterns than the rest of the year. Only data from the periods 10:00 A.M.-04:00 P.M. and 06:00 P.M.-10:00 P.M. were used, to remove traffic during rush hour and at night. Multivariate adaptive regression splines was used to evaluate the overall influence of independent variables on vehicle speed and nonparametric statistical testing was applied to test for speed differences between dark-daylight, dark-twilight, and twilight-daylight, on roads with and without road lighting. The results show that vehicle speed in general depends on several independent variables. Analyses of vehicle speed and speed differences between daylight, twilight and darkness, with and without road lighting, did not reveal any differences attributable to light conditions. However, vehicle speed decreased due to rain or snow and the decrease was higher on roads without road lighting than on roads with lighting. These results suggest that the strong association between traffic accidents and darkness or low light conditions could be explained by drivers failing to adjust their

Artificial LED lighting enhances growth characteristics and total phenolic content of Ocimum basilicum, but variably affects transplant success

OpenAIRE

Bantis, Filippos; Ouzounis, Theoharis; Radoglou, Kalliopi

2016-01-01

The morphological and phytochemical characteristics of two Ocimum basilicum cultivars (Lettuce Leaf, and Red Rubin-mountain Athos hybrid) under artificial lighting were investigated. Four LED light treatments [AP673L (high red and high red:far-red), G2 (high red and low red:far-red), AP67 (moderate blue and red and low red:far-red), and NS1 (high blue and green, high red:far-red and 1% ultraviolet)] with different colors mixing UV, blue, green, red and far-red, and fluorescent tubes (FL, high...

Diagnosing night sweats.

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Viera, Anthon J; Bond, Michael M; Yates, Scott W

2003-03-01

Night sweats are a common outpatient complaint, yet literature on the subject is scarce. Tuberculosis and lymphoma are diseases in which night sweats are a dominant symptom, but these are infrequently found to be the cause of night sweats in modern practice. While these diseases remain important diagnostic considerations in patients with night sweats, other diagnoses to consider include human immunodeficiency virus, gastroesophageal reflux disease, obstructive sleep apnea, hyperthyroidism, hypoglycemia, and several less common diseases. Antihypertensives, antipyretics, other medications, and drugs of abuse such as alcohol and heroin may cause night sweats. Serious causes of night sweats can be excluded with a thorough history, physical examination, and directed laboratory and radiographic studies. If a history and physical do not reveal a possible diagnosis, physicians should consider a purified protein derivative, complete blood count, human immunodeficiency virus test, thyroid-stimulating hormone test, erythrocyte sedimentation rate evaluation, chest radiograph, and possibly chest and abdominal computed tomographic scans and bone marrow biopsy.

Globe at Night Citizen Science: Reaching for the Stars

Science.gov (United States)

Walker, C. E.; Pompea, S. M.

2017-12-01

Citizen-science is a rewardingly inclusive way to bring awareness to the public on the disappearance of the starry night sky, its cause and solutions. Globe at Night (GaN) encourages citizen-scientists worldwide to record the brightness of the night sky. During ten-days per month of moonless evenings, children and adults match the appearance of a specific constellation with 7 star maps of progressively fainter stars found at www.globeatnight.org. They then submit their choice of star map in-situ using the "webapp" on a smart device. In eleven years of the program, over 160,000 observations from 180 countries have been contributed to a light pollution map. The GaN (open) database is a source of research projects. For example, students conducted research to understand the lesser long-nosed bats' avoidance of city center at night. With its analytical tools, Fieldscope will be a conduit for comparing GaN to other databases. On-the-fly mapping enables citizen-scientists to see observations immediately. There are 4 ways of taking measurements. The online app for data reporting is in 26 languages. STEM activities for young children and problem-based learning activities for older students were created to experience real-life scenarios: role-playing sea turtles hatching (misdirected by lights on shore) or analyzing an ISS image of Houston to estimate the wasted energy, cost and carbon footprint. In-situ and on-line workshops have been given on using GaN, as well as the activities. Our Facebook page exists to encourage dialogue and bring cutting edge news. To entice interest, we had monthly newsletters and serial podcasts starring the Dark Skies Crusader. GaN has been part of special campaigns like with the National Park Service, the National Geographic BioBlitz and Tucson in 2011. We have built a community of practitioners in various ways worldwide and have metrics on behavioral changes. To maintain the community and create new partnerships, we have teamed with Sci

ANALYZING THE VELOCITY OF URBAN DYNAMIC OVER NORTHEASTERN CHINA USING DMSP-OLS NIGHT-TIME LIGHTS

Directory of Open Access Journals (Sweden)

Y. Zhou

2017-09-01

Full Text Available Stable night-time lights (NTL data from the Defense Meteorological Satellite Program Operational Line-scan System (DMSPOLS can serve as a good proxy for anthropogenic development. Here DMSP-OLS NTL data was used to detect the urban development status in northeastern China. The spatial and temporal gradients are combined to depict the velocity of urban expanding process. This velocity index represents the instantaneous local velocity along the Earth’s surface needed to maintain constant NTL condition, and has a mean of 0.36 km/yr for northeastern China. The velocity change of NTL is lower in the urban center and its near regions, and the suburbs show a relatively high value. The connecting zones between satellite cities and metropolis have also a rapid rate of NTL evolution. The dynamic process of urbanization over the study area is mainly in a manner of spreading from urban cores to edges. The rank size of the velocity for the prefectures is analyzed and a long tail distribution is found. The velocity index can provide insights for the future pattern of urban sprawl.

Analyzing the Velocity of Urban Dynamic Over Northeastern China Using Dmsp-Ols Night-Time Lights

Science.gov (United States)

Zhou, Y.

2017-09-01

Stable night-time lights (NTL) data from the Defense Meteorological Satellite Program Operational Line-scan System (DMSPOLS) can serve as a good proxy for anthropogenic development. Here DMSP-OLS NTL data was used to detect the urban development status in northeastern China. The spatial and temporal gradients are combined to depict the velocity of urban expanding process. This velocity index represents the instantaneous local velocity along the Earth's surface needed to maintain constant NTL condition, and has a mean of 0.36 km/yr for northeastern China. The velocity change of NTL is lower in the urban center and its near regions, and the suburbs show a relatively high value. The connecting zones between satellite cities and metropolis have also a rapid rate of NTL evolution. The dynamic process of urbanization over the study area is mainly in a manner of spreading from urban cores to edges. The rank size of the velocity for the prefectures is analyzed and a long tail distribution is found. The velocity index can provide insights for the future pattern of urban sprawl.

Aircraft Lighting and Transparency Lab

Data.gov (United States)

Federal Laboratory Consortium — The Advanced Lighting and Transparencies with Night Combat Lab performs radiometric and photometric measurements of cockpit lighting and displays. Evaluates the day,...

Women with hereditary breast cancer predispositions should avoid using their smartphones, tablets, and laptops at night.

Science.gov (United States)

Mortazavi, Seyed Ali Reza; Mortazavi, Seyed Mohammad Javad

2018-02-01

Breast cancer is the most common malignancy among women, both in the developed and developing countries. Women with mutations in the BRCA1 and BRCA2 genes have an increased risk of breast and ovarian cancers. Recent studies show that short-wavelength visible light disturb the secretion of melatonin and causes circadian rhythm disruption. We have previously studied the health effects of exposure to different levels of radiofrequency electromagnetic fields (RF-EMFs) such as mobile phones, mobile base stations, mobile phone jammers, laptop computers, and radars. Moreover, over the past several years, we investigated the health effects of exposure to the short wavelength visible light in the blue region emitted from digital screens. The reduction of melatonin secretion after exposure to blue light emitted from smartphone's screen has been reported to be associated with the negative impact of smartphone use at night on sleep. We have shown that both the blue light and RF-EMFs generated by mobile phones are linked to the disruption of the circadian rhythm in people who use their phones at night. Therefore, if women with hereditary breast cancer predispositions use their smartphones, tablets and laptops at night, disrupted circadian rhythms (suppression of melatonin caused by exposure to blue light emitted from the digital screens), amplifies the risk of breast cancer. It can be concluded that women who carry mutated BRCA1 or BRCA2, or women with family history of breast cancer should avoid using their smartphones, tablets and laptops at night. Using sunglasses with amber lenses, or smartphone applications which decrease the users' exposure to blue light before sleep, at least to some extent, can decrease the risk of circadian rhythm disruption and breast cancer.

Women with hereditary breast cancer predispositions should avoid using their smartphones, tablets and laptops at night

Directory of Open Access Journals (Sweden)

Seyed Ali Reza Mortazavi

2018-02-01

Full Text Available Breast cancer is the most common malignancy among women, both in the developed and developing countries. Women with mutations in the BRCA1 and BRCA2 genes have an increased risk of breast and ovarian cancers. Recent studies show that short-wavelength visible light disturb the secretion of melatonin and causes circadian rhythm disruption. We have previously studied the health effects of exposure to different levels of radiofrequency electromagnetic fields (RF-EMFs such as mobile phones, mobile base stations, mobile phone jammers, laptop computers, and radars. Moreover, over the past several years, we investigated the health effects of exposure to the short wavelength visible light in the blue region emitted from digital screens. The reduction of melatonin secretion after exposure to blue light emitted from smartphone’s screen has been reported to be associated with the negative impact of smartphone use at night on sleep. We have shown that both the blue light and RF-EMFs generated by mobile phones are linked to the disruption of the circadian rhythm in people who use their phones at night. Therefore, if women with hereditary breast cancer predispositions use their smartphones, tablets and laptops at night, disrupted circadian rhythms (suppression of melatonin caused by exposure to blue light emitted from the digital screens, amplifies the risk of breast cancer. It can be concluded that women who carry mutated BRCA1 or BRCA2, or women with family history of breast cancer should avoid using their smartphones, tablets and laptops at night. Using sunglasses with amber lenses, or smartphone applications which decrease the users’ exposure to blue light before sleep, at least to some extent, can decrease the risk of circadian rhythm disruption and breast cancer.

Minor Characters in William Shakespeare's Twelfth Night and A Midsummer Night's Dream

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Zahraa Adnan Baqer

2018-01-01

Full Text Available This paper aims at discussing the role of the minor characters in William Shakespeare's Twelfth Night and A Midsummer Night's Dream. The study assumes that without the first group of minor characters, associated with Olivia, the play Twelfth Night would lose much of its humor, and without the second group, associated with Sebastian, the play would fall apart. On the other hand, in Shakespeare's A Midsummer Night's Dream minor characters play important roles, without them, the action dose not ran smoothly, or does not ran at all. The paper falls into three sections. Section one deals with the role of each minor character in Twelfth Night.  Section two focuses on the minor characters in A Midsummer Night's Dream. Section three is a conclusion which sums up the findings of the study.

Combined effects of exposure to dim light at night and fine particulate matter on C3H/HeNHsd mice.

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Hogan, Matthew K; Kovalycsik, Taylor; Sun, Qinghua; Rajagopalan, Sanjay; Nelson, Randy J

2015-11-01

Air and light pollution contribute to fetal abnormalities, increase prevalence of cancer, metabolic and cardiorespiratory diseases, and central nervous system (CNS) disorders. A component of air pollution, particulate matter, and the phenomenon of dim light at night (dLAN) both result in neuroinflammation, which has been implicated in several CNS disorders. The combinatorial role of these pollutants on health outcomes has not been assessed. Male C3H/HeNHsd mice, with intact melatonin production, were used to model humans exposed to circadian disruption by dLAN and contaminated environmental air. We hypothesized exposure to 2.5 μm of particulate matter (PM2.5) and dLAN (5lx) combines to upregulate neuroinflammatory cytokine expression and alter hippocampal morphology compared to mice exposed to filtered air (FA) and housed under dark nights (LD). We also hypothesized that exposure to PM2.5 and dLAN provokes anxiety-like and depressive-like responses. For four weeks, four groups of mice were simultaneously exposed to ambient concentrated PM2.5 or FA and/or dLAN or LD. Following exposure, mice underwent several behavioral assays and hippocampi were collected for qPCR and morphological analyses. Our results are generally comparable to previous PM2.5 and dLAN reports conducted on mice and implicate PM2.5 and dLAN as potential factors contributing to depression and anxiety. Short-term exposure to PM2.5 and dLAN upregulated neuroinflammatory cytokines and altered CA1 hippocampal structural changes, as well as provoked depressive-like responses (anhedonia). However, combined, PM2.5 and dLAN exposure did not have additive effects, as hypothesized, suggesting a ceiling effect of neuroinflammation may exist in response to multiple pollutants. Copyright © 2015 Elsevier B.V. All rights reserved.

Systematic measurements of the night sky brightness at 26 locations in Eastern Austria

Science.gov (United States)

Posch, Thomas; Binder, Franz; Puschnig, Johannes

2018-05-01

We present an analysis of the zenithal night sky brightness (henceforth: NSB) measurements at 26 locations in Eastern Austria focussing on the years 2015-2016, both during clear and cloudy to overcast nights. All measurements have been performed with 'Sky Quality Meters' (SQMs). For some of the locations, simultaneous aerosol content measurements are available, such that we were able to find a correlation between light pollution and air pollution at those stations. For all locations, we examined the circalunar periodicity of the NSB, seasonal variations as well as long-term trends in the recorded light pollution. The latter task proved difficult, however, due to varying meteorological conditions, potential detector 'aging' and other effects. For several remote locations, a darkening of the overcast night sky by up to 1 magnitude is recorded - indicating a very low level of light pollution -, while for the majority of the examined locations, a brightening of the night sky by up to a factor of 15 occurs due to clouds. We present suitable ways to plot and analyze huge long-term NSB datasets, such as mean-NSB histograms, circalunar, annual ('hourglass') and cumulative ('jellyfish') plots. We show that five of the examined locations reach sufficiently low levels of light pollution - with NSB values down to 21.8 magSQM/arcsec2 - as to allow the establishment of dark sky reserves, even to the point of reaching the 'gold tier' defined by the International Dark Sky Association. Based on the 'hourglass' plots, we find a strong circalunar periodicity of the NSB in small towns and villages ( < 5.000 inhabitants), with amplitudes of up to 5 magnitudes. Using the 'jellyfish' plots, on the other hand, we demonstrate that the examined city skies brighten by up to 3 magnitudes under cloudy conditions, which strongly dominate in those cumulative data representations. Nocturnal gradients of the NSB of 0.0-0.14 magSQM/arcsec2/h are found. The long-term development of the night sky

First results of the spatial and temporal variation of the night sky brightness in the surroundings of Valencia

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Marco, E.; Morales Rubio, A.; Zamorano, J.; Sánchez de Miguel, A.

2017-03-01

In recent years a study of the quality of the night sky in the surroundings of the metropolitan area of Valencia has been done. To achieve this, we used a Sky Quality Meter (SQM-LE) together with a GPS in order to cover a large number of routes from very bright locations near the city of Valencia to very dark areas located more than 100 kilometres away. The objectives of the study were to determine the variation of light pollution with respect to the distance to Valencia, locate areas with a high quality night sky in order to claim for their protection and verify the contribution of smaller towns in the brightness of the sky. Since light pollution also affects biodiversity, we have especially studied its influence on the night sky close to natural parks. Night routes have been done in the interior and vicinity of the Parc de la Calderona, the Albufera and especially the Parc del T ´uria. Our study concludes that these parks are completely degraded and need an urgent protection plan against light pollution. Finally, we present the first results of our fixed detectors SQM-LU scattered throughout the Valencian territory.

Adnyamathanha Night Skies

Science.gov (United States)

Curnow, Paul

2009-06-01

Aboriginal Australians have been viewing the night skies of Australia for some 45,000 years and possibly much longer. During this time they have been able to develop a complex knowledge of the night sky, the terrestrial environment in addition to seasonal changes. However, few of us in contemporary society have an in-depth knowledge of the nightly waltz of stars above.

Biological Effects Of Artificial Illumination

Science.gov (United States)

Corth, Richard

1980-10-01

We are increasingly being warned of the possible effects of so called "polluted" light, that is light that differs in spectral content from that of sunlight. We should be concerned, we are told, because all animals and plants have evolved under this natural daylight and therefore any difference between that illuminant and the artificial illuminants that are on the market today, is suspect. The usual presentation of the differences between the sunlight and the artificial illuminants are as shown in Figure 1. Here we are shown the spectral power distribution of sunlight and Cool White fluorescent light. The spectral power distributions of each have been normalized to some convenient wavelength so that each can be seen and easily compared on the same figure. But this presentation is misleading for one does not experience artificial illuminants at the same intensity as one experiences sunlight. Sunlight intensities are ordinarily found to be in the 8000 to 10,000 footcandle range whereas artificial illuminants are rarely experienced at intensity levels greater than 100 footcandles. Therefore a representative difference between the two types of illumination conditions is more accurately represented as in Figure 2. Thus if evolutionary adaptations require that humans and other animals be exposed to sunlight to ensure wellbeing, it is clear that one must be exposed to sunlight intensities. It is not feasible to expect that artificially illuminated environments will be lit to the same intensity as sunlight

Hard Day’s Night: A Retrospective on the American Intervention in Somalia

Science.gov (United States)

2009-01-01

weapons storage areas, a Pakistani unit was badly mauled. In a lengthy firefight, Aideed’s militia killed 23 and wounded 59. UNOSOM II’s Malaysian ...Regiment (SOAR), equipped with MH60 Black Hawk utility helicopters and MH6 and AH6 “Little Bird ” light helicopters. Small numbers of communicators...Americans through the night. By most accounts, only the dauntless actions of the AH6 Little Bird pilots, flying all night long, kept the besieged

Possibilities of Architectural Lighting to Create New Style

Science.gov (United States)

Chudinova, V. G.; Bokova, O. R.

2017-11-01

The article presents the argumentation of the provision on the style-forming potential of the lighting design the sphere of which is interpreted in a wide range of genres. The area of the intersection of form-building technological and artistic aspects lies in the field of ecology which includes not only energy saving, but also the well-being of the human and the society. The theory and practice of designing the night-time image of architectural ensembles, buildings and landscapes develops much slower than the implementation of light solutions in the advertising industry. In most cases, the possibilities of lighting design are used only in the field of decorative lighting despite their huge aesthetic potential and rapidly improving technologies. The request for innovation and uniqueness usually arises on the basis of image and political ambitions of large corporations or for the positioning of powerful brands. The success of such projects becomes a driver for both creation and promotion of innovative solutions. However, in a broader scientific sense, not only the design of artificial light systems but also the optimization of the daylight usage falls into the sphere lighting design. The need for the new methods of architectural shaping is dictated by the need to introduce in the building of resource-saving lighting technologies, ecological infrastructure including alternative energy sources. The article gives the examples of different lighting design genres supplemented with illustrations. The conclusions concern the prospective directions and tasks of scientific research in the field of lighting design.

Use of an Autonomous Surface Vehicle reveals small-scale diel vertical migrations of zooplankton and susceptibility to light pollution under low solar irradiance

Science.gov (United States)

Ludvigsen, Martin; Berge, Jørgen; Geoffroy, Maxime; Cohen, Jonathan H.; De La Torre, Pedro R.; Nornes, Stein M.; Singh, Hanumant; Sørensen, Asgeir J.; Daase, Malin; Johnsen, Geir

2018-01-01

Light is a major cue for nearly all life on Earth. However, most of our knowledge concerning the importance of light is based on organisms’ response to light during daytime, including the dusk and dawn phase. When it is dark, light is most often considered as pollution, with increasing appreciation of its negative ecological effects. Using an Autonomous Surface Vehicle fitted with a hyperspectral irradiance sensor and an acoustic profiler, we detected and quantified the behavior of zooplankton in an unpolluted light environment in the high Arctic polar night and compared the results with that from a light-polluted environment close to our research vessels. First, in environments free of light pollution, the zooplankton community is intimately connected to the ambient light regime and performs synchronized diel vertical migrations in the upper 30 m despite the sun never rising above the horizon. Second, the vast majority of the pelagic community exhibits a strong light-escape response in the presence of artificial light, observed down to 100 m. We conclude that artificial light from traditional sampling platforms affects the zooplankton community to a degree where it is impossible to examine its abundance and natural rhythms within the upper 100 m. This study underscores the need to adjust sampling platforms, particularly in dim-light conditions, to capture relevant physical and biological data for ecological studies. It also highlights a previously unchartered susceptibility to light pollution in a region destined to see significant changes in light climate due to a reduced ice cover and an increased anthropogenic activity. PMID:29326985

Use of an Autonomous Surface Vehicle reveals small-scale diel vertical migrations of zooplankton and susceptibility to light pollution under low solar irradiance.

Science.gov (United States)

Ludvigsen, Martin; Berge, Jørgen; Geoffroy, Maxime; Cohen, Jonathan H; De La Torre, Pedro R; Nornes, Stein M; Singh, Hanumant; Sørensen, Asgeir J; Daase, Malin; Johnsen, Geir

2018-01-01

Light is a major cue for nearly all life on Earth. However, most of our knowledge concerning the importance of light is based on organisms' response to light during daytime, including the dusk and dawn phase. When it is dark, light is most often considered as pollution, with increasing appreciation of its negative ecological effects. Using an Autonomous Surface Vehicle fitted with a hyperspectral irradiance sensor and an acoustic profiler, we detected and quantified the behavior of zooplankton in an unpolluted light environment in the high Arctic polar night and compared the results with that from a light-polluted environment close to our research vessels. First, in environments free of light pollution, the zooplankton community is intimately connected to the ambient light regime and performs synchronized diel vertical migrations in the upper 30 m despite the sun never rising above the horizon. Second, the vast majority of the pelagic community exhibits a strong light-escape response in the presence of artificial light, observed down to 100 m. We conclude that artificial light from traditional sampling platforms affects the zooplankton community to a degree where it is impossible to examine its abundance and natural rhythms within the upper 100 m. This study underscores the need to adjust sampling platforms, particularly in dim-light conditions, to capture relevant physical and biological data for ecological studies. It also highlights a previously unchartered susceptibility to light pollution in a region destined to see significant changes in light climate due to a reduced ice cover and an increased anthropogenic activity.

Artificial Satellites and How to Observe Them

CERN Document Server

Schmude, Jr , Richard

2012-01-01

Astronomers' Observing Guides provide up-to-date information for amateur astronomers who want to know all about what it is they are observing. This is the basis for the first part of the book. The second part details observing techniques for practical astronomers, working with a range of different instruments. Every amateur astronomer sees "stars" that aren't natural objects steadily slide across the background of the sky. Artificial satellites can be seen on any night, and some are as bright as the planets. But can you identify which satellite or spent launch vehicle casing you are seeing? Do you know how to image it? Artificial Satellites and How to Observe Them describes all of the different satellites that can be observed, including communication, scientific, spy satellites, and of course, the International Space Station. Richard Schmude describes how to recognize them and even how to predict their orbits. The book tells how to observe artificial satellites with the unaided eye, binoculars and with telesc...

Stressful colours : corticosterone concentrations in a free-living songbird vary with the spectral composition of experimental illumination

NARCIS (Netherlands)

Ouyang, Jenny Q.; de Jong, Maaike; Hau, Michaela; Visser, Marcel E.; van Grunsven, Roy H. A.; Spoelstra, Kamiel

2015-01-01

Organisms have evolved under natural daily light/dark cycles for millions of years. These cycles have been disturbed as night-time darkness is increasingly replaced by artificial illumination. Investigating the physiological consequences of free-living organisms in artificially lit environments is

Stressful colours: corticosterone concentrations in a free-living songbird vary with the spectral composition of experimental illumination

NARCIS (Netherlands)

Ouyang, J.; Jong, de M.J.; Hau, M.; Visser, M.E.; Grunsven, van R.H.A.; Spoelstra, K.

2015-01-01

Organisms have evolved under natural daily light/dark cycles for millions of years. These cycles have been disturbed as night-time darkness is increasingly replaced by artificial illumination. Investigating the physiological consequences of free-living organisms in artificially lit environments is

Light pollution in ultraviolet and visible spectrum: effect on different visual perceptions.

Directory of Open Access Journals (Sweden)

Héctor Antonio Solano Lamphar

Full Text Available In general terms, lighting research has been focused in the development of artificial light with the purpose of saving energy and having more durable lamps. However, the consequences that artificial night lighting could bring to the human being and living organisms have become an important issue recently. Light pollution represents a significant problem to both the environment and human health causing a disruption of biological rhythms related not only to the visible spectrum, but also to other parts of the electromagnetic spectrum. Since the lamps emit across a wide range of the electromagnetic spectrum, all photobiological species may be exposed to another type of light pollution. By comparing five different lamps, the present study attempts to evaluate UV radiative fluxes relative to what humans and two species of insects perceive as sky glow level. We have analyzed three atmospheric situations: clear sky, overcast sky and evolving precipitable water content. One important finding suggests that when a constant illuminance of urban spaces has to be guaranteed the sky glow from the low pressure sodium lamps has the most significant effect to the visual perception of the insects tested. But having the fixed number of luminaires the situation changes and the low pressure sodium lamp would be the best choice for all three species. The sky glow effects can be interpreted correctly only if the lamp types and the required amount of scotopic luxes at the ground are taken into account simultaneously. If these two factors are combined properly, then the ecological consequences of sky glow can be partly reduced. The results of this research may be equally useful for lighting engineers, architects, biologists and researchers who are studying the effects of sky glow on humans and biodiversity.

Light pollution in ultraviolet and visible spectrum: effect on different visual perceptions.

Science.gov (United States)

Solano Lamphar, Héctor Antonio; Kocifaj, Miroslav

2013-01-01

In general terms, lighting research has been focused in the development of artificial light with the purpose of saving energy and having more durable lamps. However, the consequences that artificial night lighting could bring to the human being and living organisms have become an important issue recently. Light pollution represents a significant problem to both the environment and human health causing a disruption of biological rhythms related not only to the visible spectrum, but also to other parts of the electromagnetic spectrum. Since the lamps emit across a wide range of the electromagnetic spectrum, all photobiological species may be exposed to another type of light pollution. By comparing five different lamps, the present study attempts to evaluate UV radiative fluxes relative to what humans and two species of insects perceive as sky glow level. We have analyzed three atmospheric situations: clear sky, overcast sky and evolving precipitable water content. One important finding suggests that when a constant illuminance of urban spaces has to be guaranteed the sky glow from the low pressure sodium lamps has the most significant effect to the visual perception of the insects tested. But having the fixed number of luminaires the situation changes and the low pressure sodium lamp would be the best choice for all three species. The sky glow effects can be interpreted correctly only if the lamp types and the required amount of scotopic luxes at the ground are taken into account simultaneously. If these two factors are combined properly, then the ecological consequences of sky glow can be partly reduced. The results of this research may be equally useful for lighting engineers, architects, biologists and researchers who are studying the effects of sky glow on humans and biodiversity.

PEOPLE'S EVALUATION TOWARDS MEDIA FAÇADE AS NEW URBAN LANDMARKS AT NIGHT

Directory of Open Access Journals (Sweden)

Elyas Vahedi Moghaddam

2016-04-01

Full Text Available This paper attempts to help designers to turn a building into media facade as an attractive landmark for people’s urban night life. The literature survey points towards being dynamic and interactive with observers as the two quality dimensions for implementing this emerging lighting technology. Based on a survey of eleven selected media facades using video films to 250 students and staff at a public university, results identified twelve attributes for these two qualities. However, item analysis and exploratory factor analysis of the results determined only ten attributes actually support people’s attention towards media facade. The attributes of unique landmark, different nocturnal appearance, dynamic colour, informative lighting, artistic lighting performance, on going process, and dynamic advertisement could be categorized under the visual quality dimension. On the other hand, attributes of covert interaction, overt interaction, and predesigned interaction could be categorized under the interactive quality dimension. This study contributes in prioritizing visual qualities for guiding the attractiveness of buildings’ appearances at night, hence enabling the creation of new dynamic urban spaces when designing buildings.

Light pollution in Spain 2010

Science.gov (United States)

Sánchez de Miguel, A.; Zamorano, J.; Pila-Díez, B.; Rubio, J.; Ruiz, R.; Rodríguez-Herranz, I.; González-Pérez, A.

2011-11-01

The most recent data on electricity consumption for public lighting inSpain is presented and compared with light pollution measurements asderived from night satellite imagery. NOAA-MSP images (low-resolution)and higher resolution images obtained with conventional DSLR cameras on board the International Space Station (ISS) have been used.We show that the data can be related to night sky brightness maps with a study conducted within the Comunidad Autónoma de Madrid. Weintend to extend our work to the rest of Spain through tight collaborationwith amateur astronomers.

Human Settlements in the South-Central U.S., Viewed at Night from the International Space Station

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Dawson, Melissa; Evans, Cynthia; Stefanov, William; Wilkinson, M. Justin; Willis, Kimberly; Runco, Susan

2012-01-01

A recent innovation of astronauts observing Earth from the International Space Station (ISS) is documenting human footprints by photographing city lights at night time. One of the earliest night-time images from the ISS was the US-Mexico border at El Paso-Ciudad Juarez. The colors, patterns and density of city lights document the differences in the cultural settlement patterns across the border region, as well as within the urban areas themselves. City lights help outline the most populated areas in settlements around the world, and can be used to explore relative population densities, changing patterns of urban/suburban development, transportation networks, spatial relationship to geographic features, and more. The data also provides insight into parameters such as surface roughness for input into local and regional climate modeling and studies of light pollution. The ground resolution of night-time astronaut photography from the ISS is typically an order of magnitude greater than current Defense Meteorological Satellite Program (DMSP) data, and therefore can serve as a "zoom lens" for selected urban areas. Current handheld digital cameras in use on the ISS, optimized for greater light sensitivity, provide opportunities to obtain new detailed imagery of atmospheric phenomena such as airglow, aurora, and noctilucent clouds in addition to documenting urban patterns. ISS astronauts have taken advantage of increasingly sensitive digital cameras to document the world at night in unprecedented detail. In addition, the capability to obtain time-lapse imagery from fixed cameras has been exploited to produce dynamic videos of both changing surface patterns around the world and atmospheric phenomena. We will profile some spectacular images of human settlements over the South-Central U.S., and contrast with other images from around the world. More data can be viewed at http://eol.jsc.nasa.gov/Videos/CrewEarthObservationsVideos/. US-Mexico border is obvious by the different

A real-time monitoring system for night glare protection

Science.gov (United States)

Ma, Jun; Ni, Xuxiang

2010-11-01

When capturing a dark scene with a high bright object, the monitoring camera will be saturated in some regions and the details will be lost in and near these saturated regions because of the glare vision. This work aims at developing a real-time night monitoring system. The system can decrease the influence of the glare vision and gain more details from the ordinary camera when exposing a high-contrast scene like a car with its headlight on during night. The system is made up of spatial light modulator (The liquid crystal on silicon: LCoS), image sensor (CCD), imaging lens and DSP. LCoS, a reflective liquid crystal, can modular the intensity of reflective light at every pixel as a digital device. Through modulation function of LCoS, CCD is exposed with sub-region. With the control of DSP, the light intensity is decreased to minimum in the glare regions, and the light intensity is negative feedback modulated based on PID theory in other regions. So that more details of the object will be imaging on CCD and the glare protection of monitoring system is achieved. In experiments, the feedback is controlled by the embedded system based on TI DM642. Experiments shows: this feedback modulation method not only reduces the glare vision to improve image quality, but also enhances the dynamic range of image. The high-quality and high dynamic range image is real-time captured at 30hz. The modulation depth of LCoS determines how strong the glare can be removed.

The Citizen-Scientist as Data Collector: GLOBE at Night, Part 1

Science.gov (United States)

Ward, D. L.; Henderson, S.; Meymaris, K.; Walker, C.; Pompea, S. M.; Gallagher, S.; Salisbury, D.

2006-12-01

GLOBE at Night is an international science event designed to observe and record the visible stars as a means of measuring light pollution in a given location. Increased and robust understanding of our environment requires learning opportunities that take place outside of the conventional K-12 classroom and beyond the confines of the school day. This hands-on learning activity extended the traditional classroom and school day through 11 nights last March, when 18,000 citizen-scientists made over 4,500 observations from 96 countries. Utilizing the international networking capabilities of The GLOBE Program, GLOBE at Night was designed to make data collection and input user-friendly. Citizen-scientists were able to participate in this global scientific campaign by submitting their observations through an online database, allowing for authentic worldwide research and analysis by participating scientists. The data collected is available online in a variety of formats for use by students, teachers and scientists worldwide to assess how the quality of the night sky varies around the world. Using the online analysis tools provided by ESRI, participants were able to compare the observed data with population density and nighttime lighting datasets (DMSP Earth at Night). This comparison allowed correlations between observed data patterns and commonly used indices of population density and energy usage. This session will share our results and demonstrate how students and scientists across the globe can explore and analyze the results of this exciting campaign. We will discuss how the project team planned and executed the project in such a way that non-astronomers were able to make valid and useful contributions. We will also discuss lessons learned and best practices based on the 2006 campaign. GLOBE at Night is a collaborative effort sponsored by The GLOBE Program, the National Optical Astronomy Observatory (NOAO), Centro de Apoyo a la Didactica de la Astronomia (CADIAS

History of the Night

CERN Multimedia

CERN. Geneva

2016-01-01

The definition of the night, as the period between sunset and sunrise, is consistent and unalterable, regardless of culture and time. However the perception of the night and its economic, social, and cultural roles are subject to change. Which parameters determine these changes? What can we learn by studying them about the specific character of a culture? Why do people experience the night in different ways in different historical periods and how did this affect their lives? How do references to nocturnal activities in historical sources (works of art, narratives) reveal what the artists/authors wish to communicate to their audiences? Can the night be a meaningful subject of historical and archaeological enquiry? A study of the source material in the Greek world (ca. 400 BC-ca. AD 400) shows a continuous effort to colonize the night with activities of the day, to make the night safer, more productive, more rational, more efficient. The main motors for this change were social developments and religion, no...

Limb darkening in Venus night-side disk as viewed from Akatsuki IR2

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Satoh, Takehiko; Nakakushi, Takashi; Sato, Takao M.; Hashimoto, George L.

2017-10-01

Night-side hemisphere of Venus exhibits dark and bright regions as a result of spatially inhomogeneous cloud opacity which is illuminated by infrared radiation from deeper atmosphere. The 2-μm camera (IR2) onboard Akatsuki, Japan's Venus Climate Orbiter, is equipped with three narrow-band filters (1.735, 2.26, and 2.32 μm) to image Venus night-side disk in well-known transparency windows of CO2 atmosphere (Allen and Crawford 1984). In general, a cloud feature appears brightest when it is in the disk center and becomes darker as the zenith angle of emergent light increases. Such limb darkening was observed with Galileo/NIMS and mathematically approximated (Carlson et al., 1993). Limb-darkening correction helps to identify branches, in a 1.74-μm vs. 2.3-μm radiances scatter plot, each of which corresponds to a group of aerosols with similar properties. We analyzed Akatsuki/IR2 images to characterize the limb darkening for three night-side filters.There is, however, contamination from the intense day-side disk blurred by IR2's point spread function (PSF). It is found that infrared light can be multiplly reflected within the Si substrate of IR2 detector (1024x1024 pixels PtSi array), causing elongated tail in the actual PSF. We treated this in two different ways. One is to mathematically approximate the PSF (with a combination of modified Lorentz functions) and another is to differentiate 2.26-μm image from 2.32-μm image so that the blurred light pattern can directly be obtained. By comparing results from these two methods, we are able to reasonablly clean up the night-side images and limb darkening is extracted. Physical interpretation of limb darkening, as well as "true" time variations of cloud brightness will be presented/discussed.

An investigation into UV light exposure as an experimental model for artificial aging on tensile strength and force delivery of elastomeric chain.

Science.gov (United States)

Wahab, Siti Waznah; Bister, Dirk; Sherriff, Martyn

2014-02-01

This study investigated the effect of ultraviolet type A light (UVA) exposure on the tensile properties of elastomeric chain. UVA light exposure was used as model for artificial aging, simulating prolonged storage of elastomeric chain. Tensile strength (n = 60) was measured after exposing Ormco, Forestadent and 3M chains to UVA light for 0, 2, 3, and 4 weeks. Force decay was measured (n = 60) using chain exposed for 5, 10, and 14 days. The chains were subsequently stretched at a constant distance and the resulting forces measured at 0, 1, 24 hours and 7, 14, 21, and 28 days. This test simulated a clinical scenario of pre-stretching and subsequent shortening of elastomeric chain. Tensile strength had statistically significant difference and was directly related to the duration of ultraviolet (UV) light exposure. Forestadent chain, which had the second highest value for the 'as received' product, showed the most consistent values over time with the lowest degradation. Ormco showed the lowest values for 'as received' as well as after UV exposure; 3M chain had the highest loss of tensile strength. Force decay was also significantly different. UV light exposure of 10 days or more appears to mark a 'watershed' between products: 3M had most survivors, Forestadent chain had some survivors, depending on the time the chain was stretched for. None of the Ormco product survived UV light exposure for more than 5 days. UVA light exposure may be used as a model for artificial aging as it reduces force delivery and tensile strength of exposed chains.

47 CFR 80.925 - Electric light.

Science.gov (United States)

2010-10-01

... 47 Telecommunication 5 2010-10-01 2010-10-01 false Electric light. 80.925 Section 80.925... MARITIME SERVICES Compulsory Radiotelephone Installations for Small Passenger Boats § 80.925 Electric light. (a) If the vessel is navigated at night an electric light or dial lights which clearly illuminate the...

Circadian gene expression in peripheral blood leukocytes of rotating night shift nurses.

Science.gov (United States)

Reszka, Edyta; Peplonska, Beata; Wieczorek, Edyta; Sobala, Wojciech; Bukowska, Agnieszka; Gromadzinska, Jolanta; Lie, Jenny-Anne; Kjuus, Helge; Wasowicz, Wojciech

2013-03-01