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Author Konkal, P.; Ganesh, C.B.
Title Exposure to low or high light intensity affects pituitary-testicular activity in the fish Oreochromis mossambicus Type Journal Article
Year 2018 Publication Aquaculture Abbreviated Journal Aquaculture
Volume (down) 497 Issue Pages 109-116
Keywords Animals
Abstract Light is an important factor for the successful reproduction of most fish. In this investigation, effect of different light intensities on pituitary-testis axis was studied for a period of 21 days, under normal photoperiodic regime in the tilapia Oreochromis mossambicus. The mean numbers of spermatogonia (Sg), primary spermatocytes (Ps), secondary spermatocytes (Ss), early spermatids (Est) and late spermatids (Lst) did not show significant difference between fish exposed to moderate light intensity (MLI) and initial controls or controls, whereas the mean numbers of Sg were significantly lower in fish exposed to low light intensity (LLI) compared to those of initial controls, controls and MLI groups. However, the mean numbers of Ps, Ss, Est and Lst were significantly lower in fish exposed to LLI and high light intensity (HLI) compared to those of other experimental groups. Furthermore, in the pituitary gland, weakly immunoreactive luteinizing hormone (LH) secreting cells were observed in the proximal pars distalis (PPD) region in fish exposed to LLI and HLI in contrast to the intense immunolabelling of these cells in initial controls, controls and MLI groups. The androgen receptors showed diminished immunoreactivity in the Sertoli cells along the seminiferous lobules of the testis in fish exposed to LLI and HLI, whereas the strongly immunoreactive androgen receptors were observed in the Sertoli cells in initial controls, controls and MLI groups. Taken together, these results indicate that long-term exposure to low or high light intensity light suppresses spermatogenetic process and that this inhibition is due to reduced secretory activity of LH cells in the pituitary gland and androgen secretion in the testis of the fish O. mossambicus.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0044-8486 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 1974
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Author LeGates, T.A.; Altimus, C.M.; Wang, H.; Lee, H.-K.; Yang, S.; Zhao, H.; Kirkwood, A.; Weber, E.T.; Hattar, S.
Title Aberrant light directly impairs mood and learning through melanopsin-expressing neurons Type Journal Article
Year 2012 Publication Nature Abbreviated Journal Nature
Volume (down) 491 Issue 7425 Pages 594-598
Keywords Affect/drug effects/physiology/*radiation effects; Animals; Antidepressive Agents/pharmacology; Body Temperature Regulation/physiology/radiation effects; Circadian Rhythm/physiology; Cognition/drug effects/physiology/radiation effects; Corticosterone/metabolism; Depression/etiology/physiopathology; Desipramine/pharmacology; Fluoxetine/pharmacology; Learning/drug effects/physiology/*radiation effects; *Light; Long-Term Potentiation/drug effects; Male; Memory/physiology/radiation effects; Mice; Photoperiod; Retinal Ganglion Cells/drug effects/*metabolism/*radiation effects; *Rod Opsins/analysis; Sleep/physiology; Wakefulness/physiology
Abstract The daily solar cycle allows organisms to synchronize their circadian rhythms and sleep-wake cycles to the correct temporal niche. Changes in day-length, shift-work, and transmeridian travel lead to mood alterations and cognitive function deficits. Sleep deprivation and circadian disruption underlie mood and cognitive disorders associated with irregular light schedules. Whether irregular light schedules directly affect mood and cognitive functions in the context of normal sleep and circadian rhythms remains unclear. Here we show, using an aberrant light cycle that neither changes the amount and architecture of sleep nor causes changes in the circadian timing system, that light directly regulates mood-related behaviours and cognitive functions in mice. Animals exposed to the aberrant light cycle maintain daily corticosterone rhythms, but the overall levels of corticosterone are increased. Despite normal circadian and sleep structures, these animals show increased depression-like behaviours and impaired hippocampal long-term potentiation and learning. Administration of the antidepressant drugs fluoxetine or desipramine restores learning in mice exposed to the aberrant light cycle, suggesting that the mood deficit precedes the learning impairments. To determine the retinal circuits underlying this impairment of mood and learning, we examined the behavioural consequences of this light cycle in animals that lack intrinsically photosensitive retinal ganglion cells. In these animals, the aberrant light cycle does not impair mood and learning, despite the presence of the conventional retinal ganglion cells and the ability of these animals to detect light for image formation. These findings demonstrate the ability of light to influence cognitive and mood functions directly through intrinsically photosensitive retinal ganglion cells.
Address Department of Biology, Johns Hopkins University, Baltimore, Maryland 21218, USA
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Publisher Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0028-0836 ISBN Medium
Area Expedition Conference
Notes PMID:23151476; PMCID:PMC3549331 Approved no
Call Number IDA @ john @ Serial 238
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Author Kocifaj, M.; Bará, S.
Title Two-index model for characterizing site-specific night sky brightness patterns Type Journal Article
Year 2019 Publication Monthly Notices of the Royal Astronomical Society Abbreviated Journal
Volume (down) 490 Issue 2 Pages 1953-1960
Keywords Skyglow
Abstract The determination of the all-sky radiance distribution produced by artificial light sources is a computationally demanding task that generally requires intensive calculations. In this paper, we develop an analytical formulation that provides the all-sky radiance distribution produced by an artificial light source as an explicit and analytical function of the observation direction, depending on two single parameters that characterize the overall effects of the atmosphere. One of these parameters is related to the effective attenuation of the light beams, whereas the other accounts for the overall asymmetry of the combined scattering processes in molecules and aerosols. Using this formulation, a wide range of all-sky radiance distributions can be efficiently and accurately calculated in a short time. This substantial reduction in the number of required parameters, in comparison with other approaches that are currently used, is expected to facilitate the development of new applications in the field of light pollution research.
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Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0035-8711 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 2704
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Author Kocifaj, M.; Wallner, S.; Solano-Lamphar, H.A.
Title An asymptotic formula for skyglow modelling over a large territory Type Journal Article
Year 2019 Publication Monthly Notices of the Royal Astronomical Society Abbreviated Journal
Volume (down) 485 Issue 2 Pages 2214-2224
Keywords Skyglow
Abstract An analytical framework to predict skyglow due to distant sources is presented, which can be applied to model sky brightness from the zenith toward the horizon along a vertical plane crossing the hemisphere in the azimuthal position of a light source. Although various powerful algorithms have been developed over the last few decades, the time needed for calculation grows exponentially with increasing size of the modelling domain. This is one of the key issues in skyglow computations, because the numerical accuracy improves only slowly as the modelling domain extends. We treat the problem theoretically, by introducing an analytical formula that is well-suited for light sources located at intermediate and long distances from an observation point and allows tremendous time savings in numerical analyses, while keeping the error at a low level. Field experiments carried out in Eastern Austria provided a unique opportunity to validate the model using real-sky luminance data. The fact that the theoretical model allows the prediction of sky luminance within an acceptable error tolerance is not only in line with the experimental data, but also provides new means of remote characterization of light emissions from artificial sources. The method is particularly attractive for rapid and simple retrieval of the amount of light escaping upwards from the dominant light sources surrounding the observation point. We expect that the method can advance the numerical modelling of skyglow substantially, because it allows real-time computations for very large territories.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0035-8711 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 2258
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Author Aubé, M.; Simoneau, A.; Wainscoat, R.; Nelson, L.
Title Modeling the effects of phosphor converted LED lighting to the night sky of the Haleakala Observatory, Hawaii Type Journal Article
Year 2018 Publication Monthly Notices of the Royal Astronomical Society Abbreviated Journal
Volume (down) 478 Issue 2 Pages 1776-1783
Keywords Skyglow
Abstract 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.
Address
Corporate Author Thesis
Publisher Place of Publication Editor
Language Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0035-8711 ISBN Medium
Area Expedition Conference
Notes Approved no
Call Number GFZ @ kyba @ Serial 1907
Permanent link to this record