Artificial Light Conditions Research Articles

Strategy for Creating Highly Productive Forms of Small Radish Adapted for Cultivation under Artificial Light Conditions

A strategy for creating new radish forms adapted for cultivation under artificial lightning was developed and implemented. It is based on the original methodology of obtaining transgressive forms of various cultures with a predictable complex of economically valuable properties. Plants were grown in controlled conditions under DNaZ-400 incandescent lamps (12-h photoperiod, irradiation of 40–60 W/m2 PAR) in a small volume of the root medium. The intraspecific diversity of small radish (26 varieties of different origin) under artificial lightning has been studied. Differences in selective-valuable characteristics (early maturity, productivity, and morphological characteristics) were determined between varieties. The most-productive varieties and varieties–donors of economically valuable properties that are realized under artificial lightning with a short day and higher temperature have been revealed. Parent pairs for the subsequent obtaining of highly productive transgressive forms using the original breeding methodology have been selected. The evaluation of hybrids of the first and second generations showed the presence of heterosis on the mass of the root up to 230% in various combinations of hybridization and revealed promising transgressive forms.

High-Performance Organic Energy-Harvesting Devices and Modules for Self-Sustainable Power Generation under Ambient Indoor Lighting Environments.

Organic photovoltaics (OPVs) that perform more efficiently under artificial indoor lighting conditions than they do under sunlight are attracting growing interest as they can potentially serve as ambient energy harvesters for powering low-power electronics and portable devices for the Internet of Things. Herein, solution-processed small-molecule OPVs are demonstrated to exhibit high power conversion efficiencies exceeding 16% under white LED illumination, delivering high output power densities of up to 12.4 and 65.3 μW cm-2 at 200 and 1000 lx, respectively. Increasing the open-circuit voltage ( Voc) of OPVs is a critical factor for achieving higher indoor photovoltaic performance. Toward real applications, this small-molecule OPV system is adopted to fabricate six series-connected modules with an active area of ∼10 cm2 that are capable of generating a high output power surpassing 100 μW and a high Voc of over 4.2 V even under dimly lit indoor conditions of 200 lx. These results indicate that OPVs are promising as indoor electric power sources for self-sustainable electronic devices.

Development of an artificial cloud lighting condition system using machine vision for strawberry powdery mildew disease detection

Strawberry plants have been facing a significant proportion of diseases during cultivation, scattered throughout the field, emphasizing the need for proper diseases management. Powdery mildew is one of the major fungal strawberry disease which is typically responsible for approximately 30–70% loss of yields. The aim of this study was to develop a machine vision based artificial cloud lighting condition system for detecting strawberry powdery mildew leaf disease. The artificial cloud lighting condition system was developed consisting of custom software, two µEye colour cameras, a black cloth cover, real time kinematics-global positioning system and a ruggedized laptop computer and mounted on a mobile platform. The custom software was developed in C# programming language. The colour co-occurrence matrix based texture analysis was used to extract image features and discriminant analysis (quadratic) for classification. The study proposed mobile platform of artificial cloud lighting condition for image acquisition is beneficial. It showed higher detection accuracies of 95.26%, 95.45% and 95.37% for recall, precision and F-measure, respectively compared to 81.54%, 72% and 75.95% of recall, precision and F-measure, respectively with acquired images at natural cloud lighting condition. The feature selection results suggested the PM_GHSI feature model was best fit for this study. This study also revealed that the image acquisition speed (1.5 km h−1) and working depth (300 mm) are suitable for strawberry powdery mildew disease detection in real-time field condition.

A Filtered Sun Sensor for Solar Tracking in HCPV and CSP Systems

Tracking systems with stringent performance are required to take advantage of solar energy produced through the use of high concentration photovolatics and concentrating solar power technologies. Closed-loop tracking systems use measurements provided by a sun sensor, which picks up direct and diffuse sunlight. High levels of diffuse sunlight produce increased levels of measurement noise at the output of the sensor, which in turn limits the maximal achievable gains in the closed-loop controller and consequently the tracking performance deteriorates. The goal of this paper is to present the advantages of equipping a four-quadrant photodiode sun sensor with infrared and linear polarizing optical filters. Experimental results show that these filters reduce the effect of diffuse radiation and allow increasing the performance of sun tracking systems regardless of the type of controller used in the solar tracker. Tracking experiments are presented under indoor and outdoor conditions employing algorithms currently used in solar trackers, including proportional-integral (PI), and proportional-integral-derivative (PID) controllers, and a recently proposed cascade control law. In all the cases, the best performance is obtained with the sun sensor equipped with an infrared filter. Experiments show that an infrared optical filter reduces the filtered mean squared tracking error up to 75% under artificial light conditions and 90% under direct sunlight.

The strategy of creating highly productive forms of radish, adapted for cultivation under artificial light conditions

The strategy of creating new radish forms adapted for cultivation under artificial lighting was developed and implemented. It was based on the original methodology of obtaining transgressive forms of various cultures with a predictable complex of economically valuable properties. Plants were grown in controlled conditions, under incandescent lamps DNAZ-400 (12 hours photoperiod, irradiation of 40-60 W/m2 PAR), in a small volume of the root medium. At the first stage, the intraspecific diversity of radish (26 varieties of different origin) under artificial lighting has been studied. Differences between varieties were determined for the complex of selective-valuable characteristics (early maturity, productivity, morphological characteristics). The most productive varieties are revealed, as well as varieties donors of economically valuable properties that are realized under artificial lighting at a short day and high temperature. Parent pairs have been selected for the subsequent receipt of highly productive transgressive forms using the original breeding methodology. The evaluation of hybrids of the first and second generation showed the presence of heterosis on the mass of the root up to 230% in various combinations of hybridization and revealed promising transgressive forms.

Экспериментальное исследование фотоэлектрического генератора как альтернативного источника питания сверхпроводящих обмоток возбуждения бесконтактных авиационных электрических машин

The article considers development of an alternative current source for contactless electric power supply to superconducting excitation windings of electrical machines for on-land and aircraft applications. Based on the results of experimental investigations, the output characteristics of a photovoltaic generator constructed on the basis of the TCM-105F module and operating under the conditions of natural and artificial lighting are subjected to a comparative analysis. The possibility of using the photovoltaic generator as an alternative source of power supply for the superconducting excitation windings of contactless electrical motors and generators is shown. Schematic layouts of the power supply system for rotating superconducting windings with the use of a photovoltaic generator are proposed.

Measurement of Early Childhood Oral Health for Research Purposes: Dental Caries Experience and Developmental Defects of the Enamel in the Primary Dentition.

Epidemiological investigations of early childhood oral health rely upon the collection of high-quality clinical measures of health and disease. However, ascertainment of valid and accurate clinical measures presents unique challenges among young, preschool-age children. The paper presents a clinical research protocol for the conduct of oral epidemiological examinations among children, implemented in ZOE 2.0, a large-scale population-based genetic epidemiologic study of early childhood caries (ECC). The protocol has been developed for the collection of information on tooth surface-level dental caries experience and tooth-level developmental defects of the enamel in the primary dentition. Dental caries experience is recorded using visual criteria modified from the International Caries Detection and Assessment System (ICDAS), and measurement of developmental defects is based upon the modified Clarkson and O'Mullane Developmental Defects of the Enamel Index. After a dental prophylaxis (toothbrushing among all children and flossing as needed), children's teeth are examined by trained and calibrated examiners in community locations, using portable dental equipment, compressed air, and uniform artificial light and magnification conditions. Data are entered directly onto a computer using a custom Microsoft Access-based data entry application. The ZOE 2.0 clinical protocol has been implemented successfully for the conduct of over 6000 research examinations to date, contributing phenotype data to downstream genomics and other "omics" studies of ECC and DDE, as well as traditional clinical and epidemiologic dental research.

Patterns of wild carnivore attacks on humans in urban areas

Attacks by wild carnivores on humans represent an increasing problem in urban areas across North America and their frequency is expected to rise following urban expansion towards carnivore habitats. Here, we analyzed records of carnivore attacks on humans in urban areas of the U.S. and Canada between 1980 and 2016 to analyze the general patterns of the attacks, as well as describe the landscape structure and, for those attacks occurring at night, the light conditions at the site of the attacks. We found that several behavioral and landscape-related factors were recurrent elements in the attacks recorded. The species for which the attack locations were available (coyote and black bear) attacked in areas with different conditions of landscape structure and artificial light. Specifically, black bears attacked more frequently in areas with abundant and aggregated vegetation cover and scarce buildings and roads, while coyotes attacked in a broader range of landscape conditions. At night, black bears attacked in generally darker areas than coyotes. By providing a comprehensive perspective of the phenomenon, this study will improve our understanding of how effective strategies aimed at reducing the frequency of risky encounters in urban areas should be developed.

Cultivation of scenedesmus sp. using optimized minimal nutrients and flocculants – a potential platform for mass cultivation

ABSTRACTA major constraint in the microalgal technology is the economics involved in cultivation and harvesting. This work is focussed on the optimization of nutrients for cultivation and harvesting using ‘Scenedesmus sp’. Response surface methodology (RSM) using ‘Face centered central composite design’ (FCCD) available in Design expert 10.0.4 was used to develop the regression model for optimization of nutrients and flocculation conditions. The optimum nutrient conditions were 500 ppm of urea, 250 ppm of potassium dihydrogen phosphate and 1000 ppm of potassium hydrogen carbonate under artificial light conditions and 500 ppm of urea and 2000 ppm of potassium hydrogen carbonate under sunlight conditions. The optimum conditions were predicted using the model and compared with experimental data. The model has an R2 value of 0.9769 and 0.9798 for artificial light and sunlight conditions, respectively. In the case of harvesting studies, 98% flocculation efficiency was obtained for a combination of pH 10.4, temperature 45°C, 200 mg/l of leaf powder of Cassia auriculata. The model has an R2 value of 0.9989. The present studies indicated that cultivation of Scenedesmus sp. with the optimized nutrients and harvesting conditions facilitate a platform for energy efficient mass cultivation.

Effects of the heavy metal cadmium on photosynthetic activity and the xanthophyll cycle in Phaeodactylum tricornutum

Cadmium (Cd) is one of the most common and widespread heavy metals in the environment. Cd has adverse effects on photosynthesis that are countered by photosystem I (PSI) and photosystem II (PSII); however, the protective responses of these photosystems to heavy metal stress remain unclear. Using the model diatom Phaeodactylum tricornutum, a biological indicator that is widely used to assess the impact of environmental toxins, we simultaneously measured the effects of Cd on PSI and PSII and examined the levels of pigments in response to high light treatments before and after Cd exposure. Cd significantly reduced the quantum yield and electron transport rates of PSI and PSII. The quantum yield of non-photochemical energy dissipation in PSI due to donor side limitation increased faster than the quantum yield due to acceptor side limitation. The Cd treatment activated the P. tricornutum xanthophyll cycle under artificial light conditions, as indicated by an increased diatoxanthin content. Xanthophyll is important for photoprotection; therefore, the accumulation of diatoxanthin may down-regulate PSII activities to reduce oxidative damage. Together, our results suggest that the rapid reduction in PSII activities following Cd exposure is an adaptive response to heavy metal stress that reflects the variable exposure to external stressors in the native P. tricornutum environment.

Development of experimental methods for quantifying the human response to chromatic glazing

Thermochromic (TC) windows have the ability to regulate daylight and control the solar heat gains that shape a building's internal environment. They therefore offer the potential to improve indoor comfort and reduce building energy demand when used in place of traditional clear glazing systems. However, the quality of the luminous environment is affected due to their chromatic appearance (e.g. common TC coatings impart a bronze or blue hue), resulting in changes to correlated colour temperatures (CCT). Previous studies show that experiments performed under daylight conditions are difficult to be control, while those conducted under artificial lighting conditions cannot faithfully reproduce window properties. In order to investigate the influence of TC windows on visual performance and comfort of subjects in an efficient and economical way, an innovative test room cubicle was designed. It is a mock-up office lit by an artificial window, simulating luminous conditions filtered through two types of TC window (one blue tinted and one bronze tinted). Clear glazing was used as a reference. Objective visual tasks involving Landolt charts and subjective assessments made using questionnaires were used to determine subjects' response to the three different luminous conditions. Results show that the experimental method is effective at determining human response to chromatic glazing. Additionally, the method is flexible due to its small scale and its ability to artificially represent different window types.

ФИЗИОЛОГО-ГИГИЕНИЧЕСКИЕ АСПЕКТЫ ФОРМИРОВАНИЯ МИОПИИ У УЧАЩИХСЯ

The leading unfavorable factors of the educational environment and the educational process that contributed to the development of myopia in students were the irrational distribution of the educational load in accordance with the difficulty of subjects and the dynamics of student performance, the pronounced intensity of the learning process due to sensory loads as a result of the considerable stress of the visual analyzer in classrooms, against background insufficient artificial lighting and unfavorable air-thermal conditions in classrooms. Every third student has a visual impairment, with the leading pathology being middle degree myopia, which by the end of the 10th grade increased by 2.7 times.

태양전지가 활용된 유리온실의 인공광 특성에 관한 LED 조명 시뮬레이션 연구

This study shows the effect of natural light effect on the solar cell and DSSC (DSSC : Dye Sensitized Solar Cell) to be attached to the roof and side of the glass greenhouse and the power consumption reduction effect by controlling the artificial light source. We used Relux illumination simulation program. Simulation items were that the first was only artificial light condition, the second was not optimal control condition of artificial light with natual light, and the last was optimal control of artificial light with natual light. According to the simulation results, when the natural light is considered and the artificial light is controlled by the optimal control method, it can reduce power consumption by 59%.

Estimation of Whole Plant Photosynthetic Rate of Irwin Mango under Artificial and Natural Lights Using a Three-Dimensional Plant Model and Ray-Tracing.

Photosynthesis is an important physiological response for determination of CO2 fertilization in greenhouses and estimation of crop growth. In order to estimate the whole plant photosynthetic rate, it is necessary to investigate how light interception by crops changes with environmental and morphological factors. The objectives of this study were to analyze plant light interception using a three-dimensional (3D) plant model and ray-tracing, determine the spatial distribution of the photosynthetic rate, and estimate the whole plant photosynthetic rate of Irwin mango (Mangifera indica L. cv. Irwin) grown in greenhouses. In the case of mangoes, it is difficult to measure actual light interception at the canopy level due to their vase shape. A two-year-old Irwin mango tree was used to measure the whole plant photosynthetic rate. Light interception and whole plant photosynthetic rate were measured under artificial and natural light conditions using a closed chamber (1 × 1 × 2 m). A 3D plant model was constructed and ray-tracing simulation was conducted for calculating the photosynthetic rate with a two-variable leaf photosynthetic rate model of the plant. Under artificial light, the estimated photosynthetic rate increased from 2.0 to 2.9 μmolCO2·m−2·s−1 with increasing CO2 concentration. On the other hand, under natural light, the photosynthetic rate increased from 0.2 μmolCO2·m−2·s−1 at 06:00 to a maximum of 7.3 μmolCO2·m−2·s−1 at 09:00, then gradually decreased to −1.0 μmolCO2·m−2·s−1 at 18:00. In validation, simulation results showed good agreement with measured results with R2 = 0.79 and RMSE = 0.263. The results suggest that this method could accurately estimate the whole plant photosynthetic rate and be useful for pruning and adequate CO2 fertilization.

Different light-response patterns of coloration and related gene expression in red pears ( Pyrus L.)

Abstract The coloration of fruit peel in red pear is influenced by light. However, the various responses to light among different varieties are still unstudied. In this study, the different light-response patterns of 27 pear cultivars under artificial light conditions were observed. The results revealed three types of coloration patterns: type-I cultivars showed no coloration; type-II cultivars showed significant coloration; and type-III cultivars showed faint coloration. Cultivars ‘Mantianhong’, ‘Fojianxi’, ‘Yunhongli 1′, and ‘Starkrimson’ were chosen as representative for further analysis of anthocyanin content and components as well as gene expression related to color. Four anthocyanin components were detected in different cultivars when exposed to artificial light and natural light, and the difference in anthocyanin content led to different colored phenotypes, with a similar response under different light conditions. The expression patterns of genes encoding enzymes indicated that ANS and UFGT were decisive genes involved in anthocyanin biosynthesis for red-skinned pears, and the varying expression of these genes led to coloration differences observed between light-response patterns. The expression patterns of transcription factors indicated that the MYB10, bHLH33, and WD40 genes are involved in differential regulatory mechanisms of anthocyanin biosynthesis and coloration patterns between light-response patterns. The expression of light-responsive genes indicated that the expressions of HY5, PhyA, COP1, DET1, and PIF3 genes are involved in the differential regulatory mechanisms of anthocyanin biosynthesis and coloration patterns between light-response patterns. The results provide an important reference for studying the molecular mechanism of light response and coloration in red pear and lay the foundation for future studies on red pear coloration research.

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

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.

Singing from North to South: Latitudinal variation in timing of dawn singing under natural and artificial light conditions.

Animals breeding at northern latitudes experience drastic changes in daily light conditions during the breeding season with decreasing periods of darkness, whereas those living at lower latitudes are exposed to naturally dark nights throughout the year. Nowadays, many animals are also exposed to artificial night lighting (often referred to as light pollution). Animals strongly rely on variation in light levels to time their daily and seasonal behaviour. Previous work on passerine birds showed that artificial night lighting leads to earlier onset of dawn song. However, these studies were carried out at intermediate latitudes with more limited seasonal changes in daylength, and we still lack an understanding of the impact of artificial night lighting in relation to variation in natural light conditions. We investigated the influence of natural and artificial light conditions on the timing of dawn singing in five common songbird species in each of three regions in Europe that differed in natural variation in daylength (northern Finland, 65°N; southern Germany, 48°N; southern Spain, 37°N). In each region, we selected five peri-urban forest sites with and five without street lighting, and we recorded dawn singing at the beginning of the local breeding season. Our results show that the earliest natural singers, that is, European robins (Erithacus rubecula) and common blackbirds (Turdus merula), started dawn singing earlier along with the natural increase in night brightness in Finland, with no additional effects of artificial night lighting. In contrast, the later singers, such as, great tits (Parus major), blue tits (Cyanistes caeruleus) and chaffinches (Fringilla coelebs), showed similar onsets of dawn song relative to sunrise across the season and similar effects of artificial night lighting at all latitudes. Artificial night lighting affected great tits, blue tits and chaffinches even in northern Finland where nights became very bright. Proximate factors such as differential light sensitivities may explain why early singers showed more plastic behavioural responses to naturally and artificially bright nights. The maintenance of rhythmicity in the late singers during bright northern nights and under artificial night lighting may also be an adaptive response to predation risk or costs of sleep loss.

Toward greener polyolefins: Antioxidant effect of phytic acid from cereal waste

Phytic acid is a major by-product of the cereal industry. The present work reports the use for the first time of phytic acid as a natural antioxidant in polyolefins. Our purpose is to respond to the key concern of replacing petroleum-based polymer stabilizers with bio-based stabilizers, paying attention to the use of biomass. Advances in bio-based thermo-stabilizers are intensifying, such as proposing original compounds from plants; however, the development of photo-stabilizers has not evolved since the 1970s. In this study, the antioxidant efficiency of phytic acid is measured against thermo- and photo-oxidation conditions in polyolefins. Its activity is compared to natural α-tocopherol, and to synthetic Irganox 1010. Variations in the molecular structure of polypropylene PP–phytic acid films, artificially exposed to oxidation at 80°C, are monitored by rheology. The efficiency of phytic acid as a photo-stabilizer is assessed using accelerated artificial light conditions. The results are promising, phytic acid showing spectacular natural antioxidant potential.

English

The artificial lighting conditions which promoted growth of the gametophytes and sporophytes of brown alga Undaria pinnatifida were examined. The seaweed was subjected to continuous or intermittent white, blue, or red light. There were notable, but not significant, differences in gametophyte and sporophyte growth between continuous and intermittent (104 Hz) white light conditions. Gametophyte growth was promoted most notably by white, followed by blue light. Sporophyte growth length was promoted most notably under intermittent white light, while body length and blade area were promoted notably under continuous white light. Sporophytes under blue or red light withered considerably. The results showed that white light is more beneficial for growth of both U. pinnatifida gametophytes and sporophytes compared with blue or red light. Male and female gametophyte grew more robustly under white light regardless of whether the pattern was intermittent or continuous light. However, the results further indicated that overall continuous white light promoted growth to a greater degree than did intermittent white light. Finally, white light promoted U. pinnatifida sporophyte growth to a greater degree than blue or red light. Key words: Light wavelength, intermittent light, Undaria pinnatifida, seaweed culture, sporophyte growth.

Effect of Artificial Light Conditions on Local and Systemic Resistance Response of Tobacco to TMV Infection

Systemic acquired resistance (SAR) is effectively inducible in greenhouse and certain artificial light sources cause non-optimal growth of tobacco plants. Therefore, the morphological characteristics, local and systemic resistance response of N. tabacum cv. ‘Xanthi’ nc plants (harbouring NN resistance genes) to tobacco mosaic virus (TMV) infection under three artificial light sources with different spectral distribution were compared with greenhouse conditions. Statistical analysis of data was carried out by R package (R Core Team, 2015). Generally, artificial light sources (especially fluorescent tube, and halogen lamp) decreased the local resistance response and caused substantial morphological and developmental differences as compared to greenhouse conditions when plants were kept during their entire life (lifelong experimental regime) under these conditions. On the contrary, no or much less differences were found when plants were transferred from greenhouse to artificial light sources only at six leaf stage (short experimental regime). While induction of systemic acquired resistance (SAR) frequently decreased TMV lesion size by about 50-60% under greenhouse conditions, two of the three artificial light sources, fluorescent tube and halogen lamp were substantially and significantly less effective under short experimental regime conditions (25-35%). A metal halide light source with similarity to sunshine’s spectral distribution, however, partially mimicked the effect of greenhouse conditions indicating the importance of light spectrum among other factors in SAR induction and prevention of distorted growth of plants. Consequently, the optimization of the effect of artificial light sources is an important factor in experimental design studying signal transduction and biochemistry of SAR.