scholarly journals White Light —White Heat: The use of Fire as a Light and Heat Source in an Atrium House in Roman Pompeii

2021 ◽  
Vol 13 (1) ◽  
pp. 59-75
Author(s):  
Henrik Boman
Keyword(s):  
Heat Source ◽  
White Light ◽  
Light Conditions ◽  
Human Eye ◽  
Dark Shadow ◽  
Interior Walls

This article concerns the distribution of fire as light and heat source within the insula investigated by the ongoing Swedish Pompeii Project. Here the author suggests that fire installations as kitchens, ovens and baths were clustered in specific areas within this insula, and the installations were not efficiently used to heat the dwelling areas of the house. It is also proposed that the surfaces of the interior walls and floors of the Roman atrium house were polished in purpose to reflect and distribute light and, which is emphasised in the article, to soften the transition between brightly lit areas and areas in dark shadow. This contrast had to be eliminated for the human eye to adopt to the light conditions in the room and by that, to make the light as efficient as possible.

scholarly journals Far-Red Light Acclimation for Improved Mass Cultivation of Cyanobacteria

Metabolites ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 170 ◽  
Author(s):  
Alla Silkina ◽  
Bethan Kultschar ◽  
Carole A. Llewellyn
Keyword(s):  
Biomass Production ◽  
White Light ◽  
Light Emitting Diode ◽  
Red Light ◽  
Industrial Biotechnology ◽  
Light Conditions ◽  
Light Emitting ◽  
Mass Cultivation ◽  
Chlorogloeopsis Fritschii ◽  
Bioactive Product

Improving mass cultivation of cyanobacteria is a goal for industrial biotechnology. In this study, the mass cultivation of the thermophilic cyanobacterium Chlorogloeopsis fritschii was assessed for biomass production under light-emitting diode white light (LEDWL), far-red light (FRL), and combined white light and far-red light (WLFRL) adaptation. The induction of chl f was confirmed at 24 h after the transfer of culture from LEDWL to FRL. Using combined light (WLFRL), chl f, a, and d, maintained the same level of concentration in comparison to FRL conditions. However, phycocyanin and xanthophylls (echinone, caloxanthin, myxoxanthin, nostoxanthin) concentration increased 2.7–4.7 times compared to LEDWL conditions. The productivity of culture was double under WLFRL compared with LEDWL conditions. No significant changes in lipid, protein, and carbohydrate concentrations were found in the two different light conditions. The results are important for informing on optimum biomass cultivation of this species for biomass production and bioactive product development.

The Effects on Visually Impaired Children of Viewing Fluorescent Stimuli under Black-Light Conditions

1998 ◽  
Vol 92 (5) ◽  
pp. 313-321 ◽  
Author(s):  
S.J. LaGrow ◽  
J-P Leung ◽  
S. Leung ◽  
P. Yeung
Keyword(s):  
Visual Acuity ◽  
White Light ◽  
Visually Impaired ◽  
Low Vision ◽  
Visual Performance ◽  
Light Conditions ◽  
Black Light ◽  
High Acuity ◽  
Impaired Children ◽  
Visually Impaired Children

In this study, 30 children with low vision (divided into a high and a low visual acuity group) were presented with stimuli under four conditions (white stimuli-white light, orange stimuli-white light, white stimuli-black light, and orange stimuli-black light) and were asked to rank their preferences for the four conditions. The goal was to determine the effects of the various combinations of stimuli and lighting on the children's visual performance. The orange stimuli viewed under black light resulted in the best performance overall, benefited the low-acuity group more than the high-acuity group, and was the most-preferred condition for both groups.

Measurements of retinal aerial image modulation (AIM) for white light based on wave-front aberration of human eye

Optik ◽  
2010 ◽  
Vol 121 (1) ◽  
pp. 101-106 ◽  
Author(s):  
Tao Liu ◽  
Zhao-Qi Wang ◽  
Yan Wang ◽  
Guo-Guang Mu ◽  
Kan-Xing Zhao
Keyword(s):  
Wave Front ◽  
White Light ◽  
Aerial Image ◽  
Human Eye

Blue light effect on EEG activity – The role of exposure timing and chronotype

2019 ◽  
Vol 52 (4) ◽  
pp. 472-484
Author(s):  
P Siemiginowska ◽  
I Iskra-Golec
Keyword(s):  
Individual Differences ◽  
Blue Light ◽  
White Light ◽  
Spectral Power ◽  
Young Male ◽  
Light Conditions ◽  
Light Effect ◽  
Eeg Activity ◽  
Mixed Analysis

There is growing evidence for monochromatic blue light effects. However, the role of individual differences in it has not yet been explored. The aim of this experiment was to examine whether chronotype could moderate the monochromatic blue light effect on electroencephalographic (EEG) activity with regard to the timing of exposure. The participants were 30 young male volunteers. A within-subjects counterbalanced design was applied. There were two light conditions comparable in luminance: Monochromatic blue light of 460 nm and polychromatic white light of 6.5 lux. EEG measurements were taken after 4 hours of exposure in the morning, afternoon, and evening. EEG spectral power was categorized into five frequency ranges: delta, theta, alpha1, alpha2, and beta. Chronotypes were assessed by the Morningness-Eveningness Questionnaire. A mixed analysis of variance was applied. Significant interactions between chronotype, light conditions, and the time of the day were found in theta and alpha1 bands after exposure to monochromatic blue light. These preliminary results indicated that in morning-oriented types the spectral power of theta and alpha1 EEG bands was higher in monochromatic blue light when compared to polychromatic white light in the afternoon hours than in the morning or the evening hours. These results may indicate a decrease in alertness in monochromatic blue light in the afternoon hours in morning-oriented types. This could point to the moderating role of individual differences in the monochromatic blue light effect.

scholarly journals Green and Red Light Reduces the Disease Severity by Pseudomonas cichorii JBC1 in Tomato Plants via Upregulation of Defense-Related Gene Expression

2015 ◽  
Vol 105 (4) ◽  
pp. 412-418 ◽  
Author(s):  
Rajalingam Nagendran ◽  
Yong Hoon Lee
Keyword(s):  
Disease Severity ◽  
White Light ◽  
Disease Incidence ◽  
Red Light ◽  
Light Conditions ◽  
Pseudomonas Cichorii ◽  
Tomato Plants ◽  
Tomato Seedlings ◽  
Pathogenesis Related Protein ◽  
Dark Conditions

Light influences many physiological processes in most organisms. To investigate the influence of light on plant and pathogen interaction, we challenged tomato seedlings with Pseudomonas cichorii JBC1 by flood inoculation and incubated the seedlings under different light conditions. Tomato seedlings exposed to green or red light showed a significant reduction in disease incidence compared with those grown under white light or dark conditions. To understand the underlying mechanisms, we investigated the effects of each light wavelength on P. cichorii JBC1 and tomato plants. Treatment with various light wavelengths at 120 µmol m–2s–1 revealed no significant difference in growth, swarming motility, or biofilm formation of the pathogen. In addition, when we vacuum-infiltrated P. cichorii JBC1 into tomato plants, green and red light also suppressed disease incidence which indicated that the reduced disease severity was not from direct influence of light on the pathogen. Significant upregulation of the defense-related genes, phenylalanine ammonia-lyase (PAL) and pathogenesis-related protein 1a (PR-1a) was observed in P. cichorii JBC1-infected tomato seedlings grown under green or red light compared with seedlings grown under white light or dark conditions. The results of this study indicate that light conditions can influence plant defense mechanisms. In particular, green and red light increase the resistance of tomato plants to infection by P. cichorii.

scholarly journals Morning Sleep Inertia in Alertness and Performance: Effect of Cognitive Domain and White Light Conditions

PLoS ONE ◽  
2013 ◽  
Vol 8 (11) ◽  
pp. e79688 ◽  
Author(s):  
Nayantara Santhi ◽  
John A. Groeger ◽  
Simon N. Archer ◽  
Marina Gimenez ◽  
Luc J. M. Schlangen ◽  
...  
Keyword(s):  
White Light ◽  
Cognitive Domain ◽  
Light Conditions ◽  
Performance Effect ◽  
Sleep Inertia ◽  
And Performance

scholarly journals Ecophysiology of seed germination in Mediterranean geophytes. 1. Muscari spp

2002 ◽  
Vol 12 (3) ◽  
pp. 193-201 ◽  
Author(s):  
Maria A. Doussi ◽  
Costas A. Thanos
Keyword(s):  
Seed Germination ◽  
White Light ◽  
Mediterranean Climate ◽  
Germination Rate ◽  
Red Light ◽  
Rainfall Regime ◽  
Light Conditions ◽  
Rainy Period ◽  
Germination Characteristics ◽  
The Mediterranean

Ecophysiological aspects of seed germination were investigated in four Mediterranean geophytes of the genus Muscari (Liliaceae): M. comosum (tassel hyacinth), M. neglectum (common grape hyacinth), M. commutatum and M. weissii. Experiments were performed at constant temperatures in the dark and under temperature and light conditions simulating those prevailing in nature during November–January, i.e. well into the rainy season of the Mediterranean climate. In all species, no primary dormancy was revealed, and germination occurred in a rather narrow range of cool temperatures (optimum at 10 or 15°C) and at a remarkably slow rate; both germination characteristics seem to be associated with autumn/winter seed germination and seedling establishment. Such a postulated strategy is ecologically advantageous within an unpredictable rainfall regime, known to prevail during the start of the rainy period of the Mediterranean climate. This strategy may also explain the spread of germination of M. comosum seeds over two consecutive years, observed by Theophrastus. Far-red light, simulating light conditions under a dense canopy, resulted in only a slight delay of germination compared to dark controls. Diurnal white light, qualitatively simulating natural daylight, caused a significant decrease of the germination rate in all four species studied. Moreover, white light was found to suppress considerably final seed germination (photoinhibition) in M. weissii and M. neglectum; in the latter species, prolonged imbibition under white light also led to the induction of secondary dormancy.

scholarly journals Sensory and Objective Quality Attributes of Beta-carotene and Lycopene-rich Tomato Fruit

2005 ◽  
Vol 130 (2) ◽  
pp. 244-251 ◽  
Author(s):  
John Stommel ◽  
Judith A. Abbott ◽  
Robert A. Saftner ◽  
Mary J. Camp
Keyword(s):  
Fruit Quality ◽  
White Light ◽  
Chemical Constituents ◽  
Tomato Fruit ◽  
Beta Carotene ◽  
Quality Attributes ◽  
Eating Quality ◽  
Cherry Tomato ◽  
Light Conditions ◽  
High Beta

Consumer acceptance of fresh and processed tomato (Lycopersicon esculentum Mill.) products is influenced by product appearance, flavor, aroma, and textural properties. Color is a key component that influences a consumer's initial perception of quality. Beta-carotene and lycopene are the principal carotenoids in tomato fruit that impart color. Analytical and sensory analyses of fruit quality constituents were conducted to assess real and perceived differences in fruit quality between orange-pigmented, high-beta-carotene cherry tomato genotypes and conventional lycopene-rich, red-pigmented cherry tomato cultivars. Thirteen sensory attributes were evaluated by untrained consumers under red-masking light conditions where differences in fruit color could not be discerned and then under white light. Panelists preferred the appearance of the red-pigmented cultivars when viewed under white light, but scored many of the other fruit-quality attributes of red- and orange-pigmented genotypes similarly whether they could discern the color or not. Irrespective of light conditions, significant genotype effects were noted for fruit appearance, sweetness, acidity/sourness, bitterness, tomato-like flavor, unpleasant aftertaste, firmness in fingers, juiciness, skin toughness, chewiness, bursting energy, and overall eating quality. Attributes whose scores differed between white and red-masking lights were intensities of tomato aroma, tomato-like flavor, sweetness, bursting energy, juiciness, and overall eating quality. The results demonstrated a color bias favoring red-pigmented fruit and highlight the influence that color has on perception of tomato fruit quality, particularly on tomato-like flavor, juiciness, and overall eating quality. Interactions between fruit chemical constituents likely influenced perceptions of quality. High-beta-carotene genotypes contained higher levels of sugars and soluble solids and equal or higher titratable acidity than the red-pigmented cultivars. Total volatile levels did not differ among genotypes; however, several individual volatiles were significantly higher in high-beta-carotene genotypes.

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