Daylight Intensity Research Articles

Metabolomics reveals the within-plant spatial effects of shading on tea plants.

It is well known that green tea made from fully developed leaves located at the base of young shoots is of lower quality than that made from the still developing leaves located on the top of the shoot. It has additionally been shown that plant shading can significantly improve green tea quality. Here, we aimed to get more insight into the effects of shading on the overall metabolome in different parts of the tea shoots. To do this, field-grown tea plants were shaded by coverage with either a straw layer or a black net, both blocking the daylight intensity for more than 90%. Both the first (i.e. still developing) leaf and the fourth (i.e. fully developed) leaf, as well as the stem of young shoots were harvested and subjected to complementary untargeted metabolomics approaches, using accurate mass LC-Orbitrap-Fourier transform mass spectrometry (FTMS) for profiling both semi-polar and lipid-soluble compounds and GC-TOF-MS for profiling polar compounds. In total, 1419 metabolites were detected. Shading resulted in a decreased ratio of polyphenols to amino acids (which improves the quality of green tea) and lower levels of galloylated catechins in the shoots. The positive effect of shading on the amino acid/catechin ratio was more pronounced in the fully developed (fourth) than in the developing (first) leaves. Furthermore, many metabolites, especially organic acids, carbohydrates and amino acids, showed differential or opposite responses to the shading treatments between the three shoot tissues investigated, suggesting a within-plant spatial regulation or transport/redistribution of carbon and nitrogen resources between the tissues of the growing young shoots. This work provides new insight into the spatial effects of shading on tea plants, which could further help to increase tea quality by improving cultivation measures for plant shading.

Impacts of leaf removal and shoot thinning on cumulative daily light intensity and thermal time and their cascading effects of grapevine (Vitis vinifera L.) berry and wine chemistry in warm climates

Leaf removal (LR), shoot thinning (ST) and their combination (LRST) are known to increase berry solar exposure affecting berry composition and consequently improving wine quality and antioxidant properties. We hypothesized that LR, ST or their combination (LRST) would affect flavonoid content during berry ripening by means of changes of the berry microclimate (light and temperature) as well as wine composition, quality, and antioxidant properties. Thermal time and sum of light intensity thresholds were different to achieve the maximum berry anthocyanin and flavonol contents. ST mostly affected wine characteristics by increasing alcoholic content, acidity, hue and phenolic substances. Wine antioxidant capacity decreased in ST wines likely by decreases in catechin and quercetin contents. ST and LRST increased proanthocyanidin polymerization and decreased monomeric flavan-3-ols, which may reduce wine bitterness and enhance astringency. Therefore, the management of canopy should take into account the warming trends in viticulture regions, rather than being applied preemptively.

Performance of Visible-Light-Driven Photocatalytic Pavement in Reduction of Motor Vehicles’ Exhaust Gas

Titanium dioxide (TiO2) is a widely used photocatalyst that can oxidize motor vehicle exhaust, for example, carbon monoxide (CO), nitrogen oxides (NOx), hydrocarbons, and sulfur dioxide, under the irradiation of sunlight. It has been reported that nano-scale TiO2 particles can be effectively used to modify the concrete-asphalt pavement, and make it as a photocatalytic pavement. However, the pure TiO2 additive limits its absorption spectrum to the ultraviolet region, which only occupies a small portion of sunlight irradiance. To increase the utilization of the full spectrum of sunlight, it has been demonstrated that doping TiO2 with substances such as Carbon (C), Nitrogen (N), or metal can reduce the band-gap and extend the threshold of the absorption spectrum to the visible light region. Therefore, doped-TiO2 has a better photocatalytic performance under sunlight irradiation. This paper conducted computational simulation of the kinetics of photocatalytic pavement to quantify the efficiency of doped-TiO2 embedded pavement in reducing exhaust gas from motor vehicles. A three-dimensional model is developed on a section of local road with doped-TiO2 embedded pavement. The effects of doped-TiO2 concentration, daylight conditions, and traffic flow conditions on the removal of NOx and CO were studied. The results indicate that the pavement with doped-TiO2 coating is effective to remove CO and NOx under different traffic density and daylight intensity conditions. Compared with UV activated TiO2, visible-light-activated doped-TiO2 features significantly higher removal efficiency of poisonous exhaustive gas including NOx and CO.

Evaluating and visualizing perceptual impressions of daylighting in immersive virtual environments

ABSTRACT This paper proposes a gamified approach to collect and visualize human perception of daylighting in large-scale indoor environments using immersive virtual environments (IVEs). The developed system was tested by 20 participants, where their daylighting preferences for the virtual environment were collected at two daytimes through snapshotting and evaluating their points of interest in terms of brightness, as well as their evaluation of the system and daylight quality. Afterward, participants’ feedback was visualized into a perceptive lighting map (PLM) and compared to an image-based quantitative metric. The results of this experimental study found a tendency among participants to report more feedback in areas with large daylight portals rather than other areas with similar light intensity. Additionally, results from both subjective and simulation-based metrics showed consistency in defining daylight intensity, as well as explained the occurrence of contradicting user evaluations of some identical areas in IVE as a result of high contrast in brightness. The findings showed the adequacy of the proposed system as a visual source of user-centered feedback to daylighting in the early stages of design, as well as a supplement tool for building performance simulations (BPS).

DAYLIGHT CONTROL USING BUILDING ENVELOPE FOR KUNSTHAUS ZURICH

Generally and in most cases for museums, daylight is an integral part of interior illumination. This is due to daylight’s full spectrum and its ability to showcase the arts’ story, meaning and emotions. Moreover, dependingon the museum’s location, the availability of daylight varies greatly and this impacts the experience of seeing art. Various forms of art collection require different level and intensity of daylight for optimum viewing at any angle. For paintings especially, daylight plays a crucial part but also comes with some consequences. No paintings are immune to infra-red and ultra violet which are part of the daylight’s spectrum. This research will focus on Kunsthaus Zurich in Switzerland as the author’s case study. Originally designed with the same façade design for all elevations, this research will attempt to elaborate a new façade design with regards to its specific elevation and the building programs it will ultimately enclose. Different building elevations’ orientation requires different treatment and the outcome of this research will be comprehensive applications in each building elevation in responds to the daylight movement throughout the year. Keywords: daylight, museum, building envelope, computer simulation

Thermal lens with passively tuned focal length formed in a photochromic material.

A new, to the best of our knowledge, way of tuning the focal length of a thermal lens is presented. The thermal lens is formed in a photochromic thermo-optical material, through illumination of the material by a heating laser beam of constant power. The tunability of the lens is achieved by changing the absorption coefficient of the thermo-optical material at the heating laser beam wavelength. This change is obtained by modifying the intensity of the additional, flat in profile, light of a wavelength different than that of the heating laser beam. The change in intensity of this light may follow from the effects of external factors, as, e.g., decrease in daylight intensity. Therefore, the lens may be considered as a passive auto-tuning lens, with focal length auto-adjusting to the external illumination.

Can skyglow reduce nocturnal melatonin concentrations in Eurasian perch?

Artificial light at night (ALAN) changes the natural rhythm of light and darkness and can impair the biorhythms of animals, for example the nocturnal melatonin production of vertebrates, which serves as a proxy for daily physiological rhythms. Freshwater fish are exposed to ALAN in large urban and suburban areas in the form of direct light or in the form of skyglow, a diffuse brightening of the night sky through the scattered light reflected by clouds, atmospheric molecules, and particles in the air. However, investigations on the sensitivity of melatonin production of fish towards low intensities of ALAN in the range of typical skyglow are rare. Therefore, we exposed Eurasian perch (Perca fluviatilis) to nocturnal illumination levels of 0.01 lx, 0.1 lx and 1 lx and a control group with dark nights and daylight intensities of 2900 lx in all groups. After ten days of exposure to the experimental conditions, tank water was non-invasively sampled every 3 h over a 24 h period and melatonin was measured by ELISA. Melatonin was gradually reduced in all treatments with increasing intensity of ALAN whereas rhythmicity was maintained in all treatment groups although at 1 lx not all evaluated parameters confirmed rhythmicity. These results show a high sensitivity of Eurasian perch towards ALAN indicating that low light intensities of 0.01 lx and 0.1 lx as they occur in urban and suburban areas in the form of skyglow can affect the physiology of Eurasian perch. Furthermore, we highlight how this may impact perch in their sensitivity towards lunar rhythms and the role of skyglow for biorhythms of temperate freshwater fish.

Effect of Supplementary Lighting Duration on Growth and Activity of Antioxidant Enzymes in Grafted Watermelon Seedlings

Insufficient exposure to light in the winter may result in a longer production periods and lower quality of seedlings in greenhouses for plug growers. Supplementary artificial lighting to plug seedlings may be one solution to this problem. The objective of this study was to assess the effects of the duration of the supplementary light on the growth and development of two watermelon cultivars, ‘Speed’ and ‘Sambok Honey’ grafted onto ‘RS-Dongjanggun’ bottle gourd rootstocks (Lagenaria siceraria Stanld). Seedlings were grown for 10 days in a glasshouse with an average daily natural light intensity of 340 μmol·m−2·s−1 photosynthetic photon flux density (PPFD) and daily supplementary lighting of 8, 12 or 16 h from mixed LEDs (W1R2B1, chip ratio of white:red:blue = 1:2:1) at a light intensity of 100 μmol·m−2·s−1 PPFD, a group without supplementary light was set as the control (CK). The culture environment in a glasshouse had 25/15 °C day/night temperatures, an 85 ± 5% relative humidity, and a natural photoperiod of 8 h. The results showed that all the growth and development parameters of seedlings grown with supplementary light were significantly greater than those without supplementary light (CK). The 12 and 16 h supplementary light resulted in greater growth and development parameters than the 8 h supplementary light did. The same trend was also found with the indexes that reflect the quality of the seedlings, such as the dry weight ratio of the shoot and root, total biomass, dry weight to height ratio of scions, and specific leaf weight. The 12 h and 16 h light supplements resulted in greater Dickson’s quality indexes compared to the 8 h supplementary light, and the 12 h supplementary light showed the greatest use efficiency of the supplementary light. 16 h of daily supplementary light significantly increased the H2O2 content and the antioxidant enzyme activities in seedlings compared to the other treatments. This indicated that 16 h of supplementary light led to certain stresses in watermelon seedlings. In conclusion, considering the energy consumption, 12 h of supplementary light was the most efficient in improving the quality of the two cultivars of grafted watermelon plug seedlings.

Study of Ecophysiological Responses of the Antarctic Fruticose Lichen Cladonia borealis Using the PAM Fluorescence System under Natural and Laboratory Conditions.

Antarctic lichens have been used as indicators of climate change for decades, but only a few species have been studied. We assessed the photosynthetic performance of the fruticose lichen Cladonia borealis under natural and laboratory conditions using the PAM fluorescence system. Compared to that of sun-adapted Usnea sp., the photosynthetic performance of C. borealis exhibits shade-adapted lichen features, and its chlorophyll fluorescence does not occur during dry days without rain. To understand its desiccation-rehydration responses, we measured changes in the PSII photochemistry in C. borealis under the average light intensity of dawn light and daylight and the desiccating conditions of its natural microclimate. Interestingly, samples under daylight and rapid-desiccation conditions showed a delayed reduction in Fv’/Fm’ and rETRmax, and an increase in Y(II) and Y(NPQ) levels. These results suggest that the photoprotective mechanism of C. borealis depends on sunlight and becomes more efficient with improved desiccation tolerance. Amplicon sequencing revealed that the major photobiont of C. borealis was Asterochloris irregularis, which has not been reported in Antarctica before. Collectively, these results from both field and laboratory could provide a better understanding of specific ecophysiological responses of shade-adapted lichens in the Antarctic region.

Dynamic LED-light versus static LED-light for depressed inpatients: study protocol for a randomised clinical study

IntroductionRetrospective studies conducted in psychiatric inpatient wards have shown a relation between the intensity of daylight in patient rooms and the length of stay, pointing to an antidepressant effect of...

Plastic bags as simple photobioreactors for cyanobacterial hydrogen production outdoors in Moscow region

The application of transparent plastic bags with a gas barrier layer as inexpensive photobioreactors for H2 production by the cyanobacterium Anabaena sp. PCC 7120 ∆Hup mutant cells was explored outdoors in Moscow region for the first time. Two experiments were performed in July and August, the average daily temperature being 21.7 and 20.6 °C, the average daily light intensity being 290 and 340 µmol photon m−2 s−1 in experiment #1 and #2, respectively. The maximal H2 production rate was 20.6 mL day−1 L−1 of culture, with accumulation of 33.2 mL L−1 during 5 days and a final H2 content of 1.1% (v/v). Molecular nitrogen added to the Ar gas at 3.3% significantly affected neither the rate nor the duration of H2 production. Low morning temperatures as well as high daytime light intensities (especially at low cell concentrations) seemed to reduce the H2 production rate. The activities obtained were lower as compared to the previously reported data. It could be attributable to suboptimal weather conditions and simple device arrangement. However, results prove that H2 production by cyanobacteria is still feasible outdoors in plastic bags, the cheapest photobioreactors.

Optimization of Atrium Geometry in an Office Building in Terms of Daylighting - a Case Study

The importance of daylighting in the design of microclimate for work and living spaces. Legislation and legislative requirements for daylighting and combined lighting of workspaces in Slovakia. Theoretical analysis of physical determinants affecting the function, geometrical design, and location of atria in buildings in terms of optimizing the light comfort in work and relax spaces. Exterior atria and their dimensions considering the boundary conditions of the site. Optimizing atria geometry depending on its function and location in terms of daylight distribution. Influence of the atrium height and self-shading on the daylight distribution in workspaces. Daylight intensity and evenness in the offices with windows facing exterior atria - model solutions. Designing atrium geometry for an office building considering microclimate optimization and light comfort in spaces for work and relax in terms of safety and energy efficiency - a solution example.

A framework outlining a daylight responsive model for smart buildings

The intensity of daylight varies due to periodical changes in the sun’s position, changing cloud-cover over the region, and other weather-related phenomena. Thus, artificial lighting remains a major component of the overall energy consumed in smart buildings. This necessitates corrections for maintaining optimum lighting levels in these buildings, by enhancing the positioning of artificial lighting sources with respect to outdoor lighting conditions. In this paper, a methodological framework is proposed for developing a daylight responsive model to minimize energy consumption for artificial lighting. This could be achieved by optimizing the usage of natural lighting in the built-environment, with the aid of Geo-location and sun-path tracking in a simulated model using Unity software. This smart daylight responsive model integrated with Virtual Reality (VR) would aid in designing an efficient lighting system utilizing Building Information Modelling (BIM). Further, this framework would help architects, engineers, and other stakeholders to collaborate, and virtually visualize the lighting conditions in smart buildings. In conclusion, an energy-efficient model for lighting can optimize the energy usage pattern in smart buildings, effectively increasing the usage of natural lighting.

Daylight intensity analysis of secondary school buildings for environmental development

Environmental development can be achieved by implementing energy efficiency in buildings. According to International Energy Agency (IEA) data, the lighting sector consumes 20% of world electricity production, contributes 6% of global CO2 emissions and as much as 3% of world oil demand for the same purpose. Natural lighting is the best lighting source for buildings, including school buildings. By optimizing the lighting in the building, it will save energy use in the building. This study discusses the compatibility of natural lighting in junior high school classrooms and meets SNI 03-6197-2000 standards for building lighting. The method of this research is quantitative, data obtained through survey measurements directly at the study site. There are four junior high schools in the city of Makassar that were used as research samples. The sample was chosen by purposive sampling. In each school, morning measurements are carried out until noon. The results showed that most of the natural light in junior high school classrooms in Makassar City was below the average lighting standards of SNI classrooms. A total of 75.00% of the SNI standard is average for classrooms and only 25.00% exceeds the SNI standard value.

Daily Physical Activity Among Toddlers: Hip and Wrist Accelerometer Assessments.

Physical activity (PA) habits seem to track over time from as young as early childhood. For children under age 3 years, wearable sensor-measured PA levels have begun to be investigated. The aims of this study were to evaluate the feasibility of using hip- vs. wrist-worn accelerometers, and to report accelerometer-derived PA metrics among toddlers. A convenience sample of 22 toddlers aged 13 to 35 months and their mothers were recruited for this study. ActiGraph wGT3X-BT accelerometers were attached to wrist bands and waist belts. The mothers were asked to affix a wrist band and a waist belt to their participating children during waking hours for four days. They also completed an acceptability survey. Of the 22 toddlers, 19 (86%) had ≥ 3 valid days of hip data, while only 14 (64%) did so for wrist data (p = 0.16). In terms of acceptability, 18 mothers (82%) responded that the 4-day hip wear was easy, while only 13 (59%) responded that the 4-day wrist wear was easy (p = 0.19). Daily light-intensity PA (LPA) was on average 161 min, and daily moderate- and vigorous-intensity PA (MVPA) was on average 47 min, as determined using published hip accelerometer cut-points. There were no significant differences in LPA or MVPA by age or by sex. In conclusion, this study suggests that hip placement of an ActiGraph accelerometer is more feasible than wrist placement among toddlers.

STUDI HABITAT DAN SUMBER PAKAN LEBAH KELULUT DI KAWASAN CAGAR ALAM GUNUNG NYIUT DESA PISAK KABUPATEN BENGKAYANG

Kelulut Bees is a stingless bee that produces honey, in the area of Gunung Nyiut Nature Reserve Kelulut Bees lives naturally with nests on tree trunks. It is not yet known how the habitat and sources of feed so that it is necessary to do research on the study of habitat and feed sources of Kelulut Bees. This study aims to obtain information about the condition of habitat and feed sources of Kelulut Bees. The method used was a survey with double plots which purposively placed, then identified the condition of habitat and feed sources. Types of hornet bees found were: Heterotrigona itama, Tetragonula laeviceps, Geniotrigona thoracica, Trigona carbonaria and Trigona drescheri. The bees nesting place were in living trees is (52%), dead trees (20%) and soil (28%). Daily mean temperature, air humidity and light intensity were 28.81 °C, 83.06%, and 583.76%. Soil type is PMK with pH 4.4, soil temperature 26.6 C °, soil moisture 26%. Altitude ± 360 masl. Tree analysis was dominated by Xanthophyllum amoenum 36.38%, Lepisanthes tetraphylla 38.01%, Syzgium chloranthum 45.8%, and Bellucia pentamera seedlings 51.58%. The feed sources at the observation sites were dominated by the family Myrtaceae and Dipterocarpaceae, while outside the plots the feed source was dominated by Cocos nucifera L, Durio zibethinus, Nephelium lappaceum L, Syzygium aqueum.Keywords : Feed source, Gunung Nyiut, habitat, kelulut bees, Nature Reserve.

Apricot-based agroforestry system in Southern Xinjiang Province of China: influence on yield and quality of intercropping wheat

Agroforestry is a common traditional practice in China, especially in Southern Xinjiang, Northwest China. However, the productivity of many agroforestry systems has been lower than expected in recent years. We chose an apricot (Prunus armeniaca L.)/wheat (Triticum aestivum L.) intercropping system to investigate the influence of apricot tree shade intensity on the grain yield and quality of intercropping wheat in Southern Xinjiang Province. We found that the mean daily light intensity in the east-row, inter-row, and west-row positions (apricot trees were planted in north–south orientation) in the intercropping systems decreased by 61.5%, 42.2%, and 63.6%, respectively, compared to the monoculture wheat. Correspondingly, the mean daily photosynthesis rate decreased by 52.0%, 28.4%, and 38.8%, respectively. The total florets, fertile florets, total spikelets, fertile spikelets, and grain yield and its components (including spike number, grains per spike, and thousand grain weight), and the total N and P contents of intercropping wheat in apricot-based intercropping systems were all significantly decreased compared to monoculture wheat. However, the protein content and wet gluten content of intercropped wheat were significantly increased compared to monoculture wheat. We did not find significant differences in any parameters among east-row, inter-row, and west-row positions in intercropping systems.

Effect of environmental factors and changes in the body condition score on the onset of the breeding season in mares.

Several methods have been proposed to advance the onset of the breeding season in horses. Most of them are based on the exposure to an artificial lighting period combined with hormonal treatments. Mares exposed to an artificial photoperiod are most often housed indoors where the ambient temperature is often higher than the outside temperature. Mares held in barns are also exposed to different daylight intensities than horses kept outside, depending on the architecture. In the current study, we evaluated the impact of ambient temperature, daylight intensity and changes in body condition score (BCS) on the timing of first ovulation after winter anestrus in mares exposed to an artificial photoperiod. Mares (n=211) were housed in barns with different ambient temperature and daylight exposure but with the same artificial photoperiod exposure (except for a natural photoperiod control group). Artificial photoperiod as well as an increase in BCS over the winter significantly advanced the first spring ovulation. The BCS at the start and end of the anestrus period did not have an effect on the interval to first ovulation and neither did the modest increase in ambient temperature in the barn. However, a higher light intensity during the daytime significantly advanced the first spring ovulation. The results of this study suggest that exposure to more sunlight advances the onset of the breeding season. This effect is likely mediated through the biological effect of short wavelength blue light and its impact on melatonin suppression and biological rhythms. We suggest that greater/direct exposure to the blue light component of daylight improves the response to the artificial photoperiod. The results of the present study can further assist to optimize the conditions that lead to an efficient spring transition of breeding mares.

Supplementary Light Source Affects Growth, Metabolism, and Physiology of Adenophora triphylla (Thunb.) A.DC. Seedlings.

Adenophora triphylla (Thunb.) A.DC., a well-known herbaceous medicinal species, has been reported to protect against human obesity, cancer, and inflammation. Supplementary lighting is a practical strategy to improve crop quality, especially at a propagation stage. However, there has been no study available on the optimal supplementary light source for the commercial production of A. triphylla seedlings. In this study, plug seedlings were cultivated in a greenhouse for four weeks under an average daily light intensity of 490 μmol·m−2·s−1 PPFD coming from the sun and a supplemental lighting (16 h per day) at 120 μmol·m−2·s−1 PPFD provided by high pressure sodium (HPS), metal halide (MH), far-red (FR) light, white LED (red: green: blue = 2:4:3, LED-w), or mixed (red: green: blue = 4:1:4) LED (LED-mix). The results showed that LED-mix, with a higher percentage of red and blue light, substantially promoted seedling growth compared to other treatments by increasing stem diameter, biomass, specific leaf weight, and root to shoot ratio. The LED-mix also promoted accumulation of soluble sugar, starch, and chlorophyll in the tissue and increased contents of total phenols and flavonoids. Moreover, stomata density and pore area per leaf area under the LED-mix were remarkably greater than those under other treatments. Furthermore, the Western blot analysis revealed that the expression of photosynthetic protein, D1, was notably enhanced by the LED-mix as compared with other light sources. In addition, the LED-mix alleviated the oxidative damage of seedlings by improving enzymatic and nonenzymatic antioxidant systems. Collectively, these results suggest that the LED-mix was the optimal supplementary light source for the production of highest quality A. triphylla seedlings.

Low Daytime Light Intensity Disrupts Male Copulatory Behavior, and Upregulates Medial Preoptic Area Steroid Hormone and Dopamine Receptor Expression, in a Diurnal Rodent Model of Seasonal Affective Disorder.

Seasonal affective disorder (SAD) involves a number of psychological and behavioral impairments that emerge during the low daytime light intensity associated with winter, but which remit during the high daytime light intensity associated with summer. One symptom frequently reported by SAD patients is reduced sexual interest and activity, but the endocrine and neural bases of this particular impairment during low daylight intensity is unknown. Using a diurnal laboratory rodent, the Nile grass rat (Arvicanthis niloticus), we determined how chronic housing under a 12:12 h day/night cycle involving dim low-intensity daylight (50 lux) or bright high-intensity daylight (1,000 lux) affects males’ copulatory behavior, reproductive organ weight, and circulating testosterone. We also examined the expression of mRNAs for the aromatase enzyme, estrogen receptor 1 (ESR1), and androgen receptor (AR) in the medial preoptic area (mPOA; brain site involved in the sensory and hormonal control of copulation), and mRNAs for the dopamine (DA) D1 and D2 receptors in both the mPOA and nucleus accumbens (NAC; brain site involved in stimulus salience and motivation to respond to reward). Compared to male grass rats housed in high-intensity daylight, males in low-intensity daylight displayed fewer mounts and intromissions when interacting with females, but the groups did not differ in their testes or seminal vesicle weights, or in their circulating levels of testosterone. Males in low-intensity daylight unexpectedly had higher ESR1, AR and D1 receptor mRNA in the mPOA, but did not differ from high-intensity daylight males in D1 or D2 mRNA expression in the NAC. Reminiscent of humans with SAD, dim winter-like daylight intensity impairs aspects of sexual behavior in a male diurnal rodent. This effect is not due to reduced circulating testosterone and is associated with upregulation of mPOA steroid and DA receptors that may help maintain some sexual motivation and behavior under winter-like lighting conditions.