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Leise, T. L., Goldberg, A., Michael, J., Montoya, G., Solow, S., Molyneux, P., et al. (2018). Recurring circadian disruption alters circadian clock sensitivity to resetting. Eur J Neurosci, in press.
Abstract: A single phase advance of the light:dark (LD) cycle can temporarily disrupt synchrony of neural circadian rhythms within the suprachiasmatic nucleus (SCN) and between the SCN and peripheral tissues. Compounding this, modern life can involve repeated disruptive light conditions. To model chronic disruption to the circadian system, we exposed male mice to more than a month of a 20 h light cycle (LD10:10), which mice typically cannot entrain to. Control animals were housed under LD12:12. We measured locomotor activity and body temperature rhythms in vivo, and rhythms of PER2::LUC bioluminescence in SCN and peripheral tissues ex vivo. Unexpectedly, we discovered strong effects of the time of dissection on circadian phase of PER2::LUC bioluminescent rhythms, which varied across tissues. White adipose tissue was strongly reset by dissection, while thymus phase appeared independent of dissection timing. Prior light exposure impacted the SCN, resulting in strong resetting of SCN phase by dissection for mice housed under LD10:10, and weak phase shifts by time of dissection in SCN from control LD12:12 mice. These findings suggest that exposure to circadian disruption may desynchronize SCN neurons, increasing network sensitivity to perturbations. We propose that tissues with a weakened circadian network, such as the SCN under disruptive light conditions, or with little to no coupling, e.g., some peripheral tissues, will show increased resetting effects. In particular, exposure to light at inconsistent circadian times on a recurring weekly basis disrupts circadian rhythms and alters sensitivity of the SCN neural pacemaker to dissection time. This article is protected by copyright. All rights reserved.
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Stevens, R. G. (2018). Comment on 'Domestic light at night and breast cancer risk: a prospective analysis of 105 000 UK women in the Generations Study'. Br J Cancer, in press.
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Petržala, J., & Kocifaj, M. (2017). Research on spectral factors towards determining nocturnal ground irradiance under overcast sky conditions in densely populated regions. Journal of Quantitative Spectroscopy and Radiative Transfer, 189, 126–132.
Abstract: Light pollution is closely correlated with the meteorological factors, specifically cloudiness that is one of the major amplifiers of night sky radiances in urban regions. Although the decisive effects of cloud deck on artificial nighttime skyglow have been recognized experimentally, the radiative transfer modelling in a heterogeneous nocturnal environment illuminated from many light sources is a non-trivial problem that is difficult to solve both theoretically and numerically. A satisfactorily accurate evaluation of ground-reaching diffuse light is, however, an important issue as some optical properties (e.g. horizontal irradiance) are usually difficult to obtain with common instruments. Overcast sky represents a special class of situations in which clouds can act as amplifiers of the light pollution of the city.
In this paper we proceeded with a simple two-stream approach to solve the scalar radiative transfer equation (RTE) under overcast conditions. The technique we are using allows for a rapid prediction of ground irradiances in densely populated regions assuming various emission functions. We have shown that the classical RTE concept can be adopted in determining the diffuse irradiance, while the model abilities are illustrated in a set of numerical experiments for low and high turbidity states.
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Geronimo, R., Franklin, E., Brainard, R., Elvidge, C., Santos, M., Venegas, R., et al. (2018). Mapping Fishing Activities and Suitable Fishing Grounds Using Nighttime Satellite Images and Maximum Entropy Modelling. Remote Sensing, 10(10), 1604.
Abstract: Fisheries surveys over broad spatial areas are crucial in defining and delineating appropriate fisheries management areas. Yet accurate mapping and tracking of fishing activities remain largely restricted to developed countries with sufficient resources to use automated identification systems and vessel monitoring systems. For many countries, the spatial extent and boundaries of fishing grounds are not completely known. We used satellite images at night to detect fishing grounds in the Philippines for fishing gears that use powerful lights to attract coastal pelagic fishes. We used nightly boat detection data, extracted by U.S. NOAA from the Visible Infrared Imaging Radiometer Suite (VIIRS), for the Philippines from 2012 to 2016, covering 1713 nights, to examine spatio-temporal patterns of fishing activities in the country. Using density-based clustering, we identified 134 core fishing areas (CFAs) ranging in size from 6 to 23,215 km2 within the Philippines’ contiguous maritime zone. The CFAs had different seasonal patterns and range of intensities in total light output, possibly reflecting differences in multi-gear and multi-species signatures of fishing activities in each fishing ground. Using maximum entropy modeling, we identified bathymetry and chlorophyll as the main environmental predictors of spatial occurrence of these CFAs when analyzed together, highlighting the multi-gear nature of the CFAs. Applications of the model to specific CFAs identified different environmental drivers of fishing distribution, coinciding with known oceanographic associations for a CFA’s dominant target species. This case study highlights nighttime satellite images as a useful source of spatial fishing effort information for fisheries, especially in Southeast Asia.
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Yates, J. (2018). Perspective: The Long-Term Effects of Light Exposure on Establishment of Newborn Circadian Rhythm. Jcsm, 14(10), 1829–1830.
Abstract: Development of newborns continues postnatally. Evidence has accumulated on the early life programming effects of light exposure on the maturing visual axis and the developing circadian rhythm. Consideration of the effects of light at night and insufficient light during the day should occur when giving anticipatory guidance in the care of newborn infants. Long-term health consequences of light imprinting may occur with inappropriate light-dark environments during the newborn period.
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