|   | 
Details
   web
Records
Author Kyba, C.C.M.; Ruhtz, T.; Fischer, J.; Hölker, F.
Title Cloud coverage acts as an amplifier for ecological light pollution in urban ecosystems Type Journal Article
Year 2011 Publication PloS one Abbreviated Journal PLoS One
Volume 6 Issue 3 Pages (down) e17307
Keywords Berlin; *Cities; *Ecosystem; Environmental Pollution/*adverse effects/analysis; *Light; Seasons; *Weather
Abstract 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.
Address Institute for Space Sciences, Freie Universitat Berlin, Berlin, Germany. christopher.kyba@wew.fu-berlin.de
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1932-6203 ISBN Medium
Area Expedition Conference
Notes PMID:21399694; PMCID:PMC3047560 Approved no
Call Number IDA @ john @ Serial 20
Permanent link to this record
 

 
Author Chellappa, S.L.; Steiner, R.; Blattner, P.; Oelhafen, P.; Gotz, T.; Cajochen, C.
Title Non-visual effects of light on melatonin, alertness and cognitive performance: can blue-enriched light keep us alert? Type Journal Article
Year 2011 Publication PloS one Abbreviated Journal PLoS One
Volume 6 Issue 1 Pages (down) e16429
Keywords Circadian Rhythm/radiation effects; Cognition/*radiation effects; Color; Cross-Over Studies; Fluorescence; Humans; *Light; Male; Melatonin/*radiation effects; Reaction Time/*radiation effects; Young Adult; blue light
Abstract BACKGROUND: Light exposure can cascade numerous effects on the human circadian process via the non-imaging forming system, whose spectral relevance is highest in the short-wavelength range. Here we investigated if commercially available compact fluorescent lamps with different colour temperatures can impact on alertness and cognitive performance. METHODS: Sixteen healthy young men were studied in a balanced cross-over design with light exposure of 3 different light settings (compact fluorescent lamps with light of 40 lux at 6500K and at 2500K and incandescent lamps of 40 lux at 3000K) during 2 h in the evening. RESULTS: Exposure to light at 6500K induced greater melatonin suppression, together with enhanced subjective alertness, well-being and visual comfort. With respect to cognitive performance, light at 6500K led to significantly faster reaction times in tasks associated with sustained attention (Psychomotor Vigilance and GO/NOGO Task), but not in tasks associated with executive function (Paced Visual Serial Addition Task). This cognitive improvement was strongly related with attenuated salivary melatonin levels, particularly for the light condition at 6500K. CONCLUSIONS: Our findings suggest that the sensitivity of the human alerting and cognitive response to polychromatic light at levels as low as 40 lux, is blue-shifted relative to the three-cone visual photopic system. Thus, the selection of commercially available compact fluorescent lights with different colour temperatures significantly impacts on circadian physiology and cognitive performance at home and in the workplace.
Address Centre for Chronobiology, Psychiatric Hospital of the University of Basel, Basel, Switzerland
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1932-6203 ISBN Medium
Area Expedition Conference
Notes PMID:21298068; PMCID:PMC3027693 Approved no
Call Number IDA @ john @ Serial 286
Permanent link to this record
 

 
Author Yasuniwa, Y.; Izumi, H.; Wang, K.-Y.; Shimajiri, S.; Sasaguri, Y.; Kawai, K.; Kasai, H.; Shimada, T.; Miyake, K.; Kashiwagi, E.; Hirano, G.; Kidani, A.; Akiyama, M.; Han, B.; Wu, Y.; Ieiri, I.; Higuchi, S.; Kohno, K.
Title Circadian disruption accelerates tumor growth and angio/stromagenesis through a Wnt signaling pathway Type Journal Article
Year 2010 Publication PloS one Abbreviated Journal PLoS One
Volume 5 Issue 12 Pages (down) e15330
Keywords Animals; *Circadian Rhythm; Disease Progression; *Gene Expression Regulation, Neoplastic; HeLa Cells; Humans; Male; Mice; Mice, Inbred BALB C; Mice, Nude; Neoplasm Transplantation; Neoplasms/*pathology; *Neovascularization, Pathologic; Nerve Tissue Proteins/metabolism; Skin/metabolism; Vascular Endothelial Growth Factor A/metabolism; Wnt Proteins/*metabolism; Oncogenesis
Abstract Epidemiologic studies show a high incidence of cancer in shift workers, suggesting a possible relationship between circadian rhythms and tumorigenesis. However, the precise molecular mechanism played by circadian rhythms in tumor progression is not known. To identify the possible mechanisms underlying tumor progression related to circadian rhythms, we set up nude mouse xenograft models. HeLa cells were injected in nude mice and nude mice were moved to two different cases, one case is exposed to a 24-hour light cycle (L/L), the other is a more “normal” 12-hour light/dark cycle (L/D). We found a significant increase in tumor volume in the L/L group compared with the L/D group. In addition, tumor microvessels and stroma were strongly increased in L/L mice. Although there was a hypervascularization in L/L tumors, there was no associated increase in the production of vascular endothelial cell growth factor (VEGF). DNA microarray analysis showed enhanced expression of WNT10A, and our subsequent study revealed that WNT10A stimulates the growth of both microvascular endothelial cells and fibroblasts in tumors from light-stressed mice, along with marked increases in angio/stromagenesis. Only the tumor stroma stained positive for WNT10A and WNT10A is also highly expressed in keloid dermal fibroblasts but not in normal dermal fibroblasts indicated that WNT10A may be a novel angio/stromagenic growth factor. These findings suggest that circadian disruption induces the progression of malignant tumors via a Wnt signaling pathway.
Address Department of Molecular Biology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1932-6203 ISBN Medium
Area Expedition Conference
Notes PMID:21203463; PMCID:PMC3009728 Approved no
Call Number IDA @ john @ Serial 162
Permanent link to this record
 

 
Author Orbach, D.N.; Fenton, B.
Title Vision impairs the abilities of bats to avoid colliding with stationary obstacles Type Journal Article
Year 2010 Publication PloS one Abbreviated Journal PLoS One
Volume 5 Issue 11 Pages (down) e13912
Keywords Analysis of Variance; Animals; Chiroptera/*physiology; Cyclonic Storms; Echolocation/*physiology; Female; Flight, Animal/*physiology; Light; Male; Space Perception/physiology/radiation effects; Vision, Ocular/*physiology/radiation effects; Vocalization, Animal/physiology
Abstract BACKGROUND: Free-flying insectivorous bats occasionally collide with stationary objects they should easily detect by echolocation and avoid. Collisions often occur with lighted objects, suggesting ambient light may deleteriously affect obstacle avoidance capabilities. We tested the hypothesis that free-flying bats may orient by vision when they collide with some obstacles. We additionally tested whether acoustic distractions, such as “distress calls” of other bats, contributed to probabilities of collision. METHODOLOGY/PRINCIPAL FINDINGS: To investigate the role of visual cues in the collisions of free-flying little brown bats (Myotis lucifugus) with stationary objects, we set up obstacles in an area of high bat traffic during swarming. We used combinations of light intensities and visually dissimilar obstacles to verify that bats orient by vision. In early August, bats collided more often in the light than the dark, and probabilities of collision varied with the visibility of obstacles. However, the probabilities of collisions altered in mid to late August, coincident with the start of behavioural, hormonal, and physiological changes occurring during swarming and mating. Distress calls did not distract bats and increase the incidence of collisions. CONCLUSIONS/SIGNIFICANCE: Our findings indicate that visual cues are more important for free-flying bats than previously recognized, suggesting integration of multi-sensory modalities during orientation. Furthermore, our study highlights differences between responses of captive and wild bats, indicating a need for more field experiments.
Address Department of Biology, University of Western Ontario, London, Ontario, Canada. dnorbach@gmail.com
Corporate Author Thesis
Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1932-6203 ISBN Medium
Area Expedition Conference
Notes PMID:21085481; PMCID:PMC2976695 Approved no
Call Number IDA @ john @ Serial 96
Permanent link to this record