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Chamorro, E., Bonnin-Arias, C., Perez-Carrasco, M. J., Munoz de Luna, J., Vazquez, D., & Sanchez-Ramos, C. (2013). Effects of light-emitting diode radiations on human retinal pigment epithelial cells in vitro. Photochem Photobiol, 89(2), 468–473.
Abstract: Human visual system is exposed to high levels of natural and artificial lights of different spectra and intensities along lifetime. Light-emitting diodes (LEDs) are the basic lighting components in screens of PCs, phones and TV sets; hence it is so important to know the implications of LED radiations on the human visual system. The aim of this study was to investigate the effect of LEDs radiations on human retinal pigment epithelial cells (HRPEpiC). They were exposed to three light-darkness (12 h/12 h) cycles, using blue-468 nm, green-525 nm, red-616 nm and white light. Cellular viability of HRPEpiC was evaluated by labeling all nuclei with DAPI; Production of reactive oxygen species (ROS) was determined by H2DCFDA staining; mitochondrial membrane potential was quantified by TMRM staining; DNA damage was determined by H2AX histone activation, and apoptosis was evaluated by caspases-3,-7 activation. It is shown that LED radiations decrease 75-99% cellular viability, and increase 66-89% cellular apoptosis. They also increase ROS production and DNA damage. Fluorescence intensity of apoptosis was 3.7% in nonirradiated cells and 88.8%, 86.1%, 83.9% and 65.5% in cells exposed to white, blue, green or red light, respectively. This study indicates three light-darkness (12 h/12 h) cycles of exposure to LED lighting affect in vitro HRPEpiC.
Keywords: Human Health; Apoptosis/*radiation effects; Biological Markers/metabolism; Caspases/metabolism; Cell Survival/radiation effects; DNA Damage; Epithelial Cells/cytology/metabolism/*radiation effects; Histones/metabolism; Humans; Light; Membrane Potential, Mitochondrial/*radiation effects; Mitochondria/*radiation effects; Photoperiod; Primary Cell Culture; Reactive Oxygen Species/metabolism; Retinal Pigment Epithelium/cytology/metabolism/*radiation effects
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Dzakovich, M., Gómez, C., & Mitchell, C. (2015). Tomatoes Grown with Light-emitting Diodes or High-pressure Sodium Supplemental Lights have Similar Fruit-quality Attributes. HortScience, 50(10), 1498–1502.
Abstract: Light-emitting diodes (LEDs) are an attractive alternative to high-pressure sodium (HPS) lamps for plant growth because of their energy-saving potential. However, the effects of supplementing broad-waveband solar light with narrow-waveband LED light on the sensory attributes of greenhouse-grown tomatoes (Solanum lycopersicum) are largely unknown. Three separate studies investigating the effect of supplemental light quantity and quality on physicochemical and organoleptic properties of greenhouse-grown tomato fruit were conducted over 4- or 5-month intervals during 2012 and 2013. Tomato cultivars Success, Komeett, and Rebelski were grown hydroponically within a high-wire trellising system in a glass-glazed greenhouse. Chromacity, Brix, titratable acidity, electrical conductivity (EC), and pH measurements of fruit extracts indicated plant response differences between lighting treatments. In sensory panels, tasters ranked tomatoes for color, acidity, and sweetness using an objective scale, whereas color, aroma, texture, sweetness, acidity, aftertaste, and overall approval were ranked using hedonic scales. By collecting both physicochemical as well as sensory data, this study was able to determine whether statistically significant physicochemical parameters of tomato fruit also reflected consumer perception of fruit quality. Sensory panels indicated that statistically significant physicochemical differences were not noticeable to tasters and that tasters engaged in blind testing could not discern between tomatoes from different supplemental lighting treatments or unsupplemented controls. Growers interested in reducing supplemental lighting energy consumption by using intracanopy LED (IC-LED) supplemental lighting need not be concerned that the quality of their tomato fruits will be negatively affected by narrow-band supplemental radiation at the intensities and wavelengths used in this study.
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Edensor, T. (2013). Reconnecting with darkness: gloomy landscapes, lightless places. Social & Cultural Geography, 14(4), 446–465.
Abstract: This paper investigates the effects and affects of darkness, a condition that is progressively becoming less familiar for those of us in the over-illuminated West. In countering the prevailing cultural understanding that darkness is a negative condition, I draw attention to other historical and cultural ways of positively valuing darkness. Subsequently, in drawing on two sites, a gloomy landscape at a dark sky park in South Scotland, and a tourist attraction in which a simulation of New York is experienced in a completely dark environment, I explore the multivalent qualities of darkness. In foregrounding the becoming of sensory experience in gloomy space, I highlight the mobilisation of alternative modes of visual perception in as well as the emergence of non-visual apprehensions, and suggest that the potentialities of darkness might foster progressive forms of conviviality, communication and imagination.
Cet article interroge les effets et les affects de l'obscurité, une condition qui devient de moins en moins courante pour ceux parmi nous dans l'occident sur-illuminé. Pour s'opposer à la compréhension culturelle dominante que l'obscurité est une condition négative, j'attire l'attention aux autres façons historiques et culturelles de faire valoir l'obscurité. Ensuite, en tirant de deux sites—l'un, un paysage sombre à un parc de ciel obscure dans l'Ecosse du Sud, et l'autre, une attraction touristique dans laquelleon a une expérience d'une simulation de New York dans un environnement complètement noirci—j'examine les qualités polyvalentes de l'obscurité. En mettant en premier plan l'émergence de l'expérience sensorielle dans l'espace sombre, je souligne la mobilisation des modes alternatives de la perception visuelle ainsi que l'émergence des appréhensions non-visuelles, et je suggère que les potentialités de l'obscurité puissent encourager des formes progressives de la convivialité, la communication, et l'imagination. Este artÃculo explora los efectos y los afectos asociadosa la oscuridad, una condición que resulta cada vez menos familiar para aquellos de nosotros que vivimos en unOccidentehiperiluminado.A los fines de contrarrestar la perspectiva cultural predominante que le asigna a la oscuridad una valoración negativa, pretendo llamar la atención sobre otras formas históricas y culturales que le otorgan un valor positivo a la oscuridad. Luego exploro las cualidades polivalentesde la oscuridad mediante el estudio de dos sitios: el paisaje sombrÃo de un parque sin iluminación artificial en el sur de Escocia y una atracción turÃstica en el que se simula la ciudad de Nueva York, experimentada en un ambiente completamente oscuro.A los fines de dar cuenta del desarrollo de experiencias sensoriales en espacios sombrÃos, destaco la movilización de modos alternativos de percepción visual asà como también la emergencia de formas de aprehensión no visuales Además,sugiero que la oscuridad tiene el potencial para promoverformas de convivencia, comunicación e imaginación progresistas. Keywords: Culture; darkness; illumination; perception; sensation; landscape; space; obscurité; illumination; perception; sensation; paysage; espace; oscuridad; iluminación; percepción; sensación; paisaje; espacio
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Imsland, A. K., Roth, B., Foss, A., Vikingstad, E., Stefansson, S. O., Pedersen, S., et al. (2009). Long-term effect of photoperiod manipulation on growth, maturation and flesh quality in Atlantic halibut. Aquaculture Research, 40(11), 1260–1269.
Abstract: The aim of this study was to investigate the effect of continuous light at different stages during the production cycle of Atlantic halibut Hippoglossus hippoglossus L. on growth, age at first maturity, endocrine parameters and flesh quality. A group of juvenile halibut [mean (SD), initial weight 191.3 g (44.7)] was reared in indoor tanks under ambient temperature conditions for 38 months until harvesting (mean final weight, 4.6 kg). The entire photoperiod experiment was divided into four phases, where the fish in each phase were exposed to either natural photoperiod (62°33′N) or continuous light (L). Thus, the following five photoperiod combinations were tested: (a) Control group (NNNN), (b) Group 2A (NLNN), (c) Group 2B (NNLN), (d) Group 2C (NNNL) and (e) Production group (LNNN). Exposure to continuous light stimulated growth, and the final mean weights of Groups 2A and 2B were 23% and 11% higher than those of the Control group (NNNN). The final plasma 11-ketotestosteron levels were lower in Groups 2A (2.94 ng mL−1) and 2B (2.46 ng mL−1) compared with the Control (5.29 ng mL−1), Group 2C (5.09 ng mL−1) and the Production group (4.78 ng mL−1) during spring 2007 (age 4 years), indicating higher age at first maturity in Groups 2A and 2B. Photoperiod regime had only a minor, and transient, effect on flesh-quality traits of the fish, whereas a significant seasonal effect was seen with a tendency towards increased gaping, lower pH, lower hardness and lower shear force in July compared with December and March.
Keywords: animals; fish; aquaculture; animal production
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Kamrowski, R. L., Sutton, S. G., Tobin, R. C., & Hamann, M. (2014). Potential applicability of persuasive communication to light-glow reduction efforts: a case study of marine turtle conservation. Environ Manage, 54(3), 583–595.
Abstract: Artificial lighting along coastlines poses a significant threat to marine turtles due to the importance of light for their natural orientation at the nesting beach. Effective lighting management requires widespread support and participation, yet engaging the public with light reduction initiatives is difficult because benefits associated with artificial lighting are deeply entrenched within modern society. We present a case study from Queensland, Australia, where an active light-glow reduction campaign has been in place since 2008 to protect nesting turtles. Semi-structured questionnaires explored community beliefs about reducing light and evaluated the potential for using persuasive communication techniques based on the theory of planned behavior (TPB) to increase engagement with light reduction. Respondents (n = 352) had moderate to strong intentions to reduce light. TPB variables explained a significant proportion of variance in intention (multiple regression: R (2) = 0.54-0.69, P < 0.001), but adding a personal norm variable improved the model (R (2) = 0.73-0.79, P < 0.001). Significant differences in belief strength between campaign compliers and non-compliers suggest that targeting the beliefs reducing light leads to “increased protection of local turtles” (P < 0.01) and/or “benefits to the local economy” (P < 0.05), in combination with an appeal to personal norms, would produce the strongest persuasion potential for future communications. Selective legislation and commitment strategies may be further useful strategies to increase community light reduction. As artificial light continues to gain attention as a pollutant, our methods and findings will be of interest to anyone needing to manage public artificial lighting.
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