The influence of taste stimuli and illumination on electrogastrogram measurements

An electrogastrogram (EGG) is considered to be an index to the autonomic nervous system of the digestive organs. In the present study, we attempted to clarify whether or not an EGG can be used to evaluate the influence of illumination, and what kinds of effect taste stimuli and illumination have on the autonomic nervous system. In this study, we used the ratio of the normal wave component of the EGG (EGG-NR: 2-4.5 cpm power/1-10 cpm power) and the amplitude of a normal wave (EGG-NI: integrated EGG of 2-4.5 cpm). Thirteen healthy males participated in 16 experimental conditions (4 lighting conditionsx4 taste stimuli). The four lighting conditions were set by combinations of illuminance levels of 200 and 1500 lx and color temperatures of 3000 and 7500 K. The four taste stimuli were sweet (glucose), salty (salt), sour (acetic acid), and bitter (quinine). The changes in EGG-NR and EGG-NI were compared for different taste conditions. The results showed that EGG-NI was not significantly affected by the different taste conditions. However, the main effect of taste on EGG-NR was significant: sweet and salty tastes were significantly higher than the bitter taste. EGG-NR and EGG-NI in different lighting conditions were also compared. The main effect of different color temperatures was also significant, but the illuminance level did not affect EGG-NR. EGG-NR increased significantly at the lower color temperature. On the other hand, EGG-NI significantly increased at the lower illuminance. These results suggest that parasympathetic nervous activity has a predominant effect on gastric activity in different lighting environments. Therefore, EGG measurements may be useful indicators for illumination environment studies.     

Evaluation of lighting conditions in relation to visual comfort in workplaces of weavers in a textile mill

The present investigation was undertaken to examine the lighting conditions in a weaving shed and also to assess visual comfort of the weavers and their visual preferences to the lighting levels. A light meter was used for measurement of the illuminances. Comfort vote cards and preference vote cards were administered on almost all the weavers (N = 95). The results indicated that the illumination levels were very low compared to the Indian Standard (1966) or IES standard (1973). A substantial proportion of the weavers had no visual comfort at work and expressed their preferences for higher illumination levels for comfort, safety, and optimum work performance. The results have been discussed and appropriate measures have been suggested for improved lighting in a cost-effective manner.     

How to reduce the impact of artificial lighting on moths: A case study on cultural heritage sites in Slovenia

In an ever more artificially illuminated world, common moth behaviour, flight-to-light, causes declines in their abundance and diversity that can have severe impacts on ecosystems. To test if it is possible to reduce the number of moths attracted to artificially illuminated objects, the original lighting of 15 cultural heritage buildings in Slovenia was substituted with blue or yellow lighting. These three illumination types differed in the amount of luminance, percentage of UV and short-wavelength light which are known to affect flight-to-light of moths. During our three-year field study approximately 20% of all known moth species in Slovenia were recorded. The blue and yellow illumination type attracted up to six times less specimens and up to four times less species compared to the original illumination type. This was true for all detected moths as well as within separate moth groups. This gives our study a high conservation value: usage of alternative, environmentally more acceptable illumination can greatly reduce the number of moths attracted to artificially illuminated objects.     

Primate Location Preference in a Double-Tier Cage: The Effects of Illumination and Cage Height

Nonhuman primates are frequently housed in double-tier arrangements with significant differences between the environments of the upper and lower-row cages. Although several studies have investigated whether this arrangement alters monkeys' behavior, no studies have addressed the two most notable differences, light and height, individually to determine their relative importance. This experiment examined how rhesus and long-tailed macaques allocated their time between the upper and lower-row cages of a 1-over-1 apartment module under different lighting conditions. In Condition A, monkeys' baseline degree of preference for the upper- and lower-row was tested. In Condition B, the lighting environment was reversed by limiting illumination in the upper-row cage and increasing illumination in the lower-row cage. In both conditions, monkeys spent more time in the upper-row cage, thus indicating a strong preference for elevation regardless of illumination. The amount of time that monkeys spent in the lower-row cage increased by 7% under reversed lighting, but this trend was not significant. These results corroborate the importance of providing captive primates with access to elevated areas.     

The difference among generations in evaluating interior lighting environment

This paper explores the difference among generations in evaluating interior lighting environment, and provides some knowledge for interior lighting design, which can accommodate all generations. Fifteen Computer Graphic pictures, which had the same dimensions (W3000 mmxH2800 mmxD6300 mm) but a different luminous environment are evaluated. Pictures are presented on a screen with a liquid crystal projector in a shaded dark room.A Semantic Differential technique with 12 subjective scales with 5 steps was used for the evaluation. Participants were chosen from 3 age groups: young, middle age, and elderly people.A difference among generations in evaluating interior lighting environment emerged. These tendencies could not be explained solely by visibility. It seems that the personal experience is closely related to the evaluation and preference of luminous environment.     

On the glutamate transport through cell envelope vesicles of Halobacterium halobium

Glutamate uptake by envelope vesicles of Halobacterium halobium was measured. Previous authors showed that the glutamate uptake needs the illumination as well as Na+ gradient across the membrane. The latter is considered to be the driving force for the uptake. No satisfactory explanation for the necessity of the illumination has not been given. We found that in the absence of Cl- in the medium, only Na+ gradient was enough to induce the glutamate uptake, i.e. no illumination was needed. Glutamate uptake was measured with various strains of H. halobium. We found that the envelope vesicles prepared from strains containing no bacteriorhodopsin showed the glutamate uptake in the dark and in the presence of Cl- in the medium provided only that Na+ gradient is imposed.     

The effect of testosterone on serum gonadotropins of castrated rats kept under different lighting conditions.

Testosterone feedback sensitivity was measured as the ability of testosterone propionate to decrease serum LH and FSH of long-term castrated (4 wk) rats under four different lighting conditions: periodic light (12L:12D), constant light (LL), constant darkness (DD), and dim night illumination (1 lx) with a 12L:12D photoperiod. Rats were exposed to the different lighting conditions for 1 wk, during which they received daily testosterone propionate (125 micrograms or 250 micrograms s.c.). At the end of the experiment the rats were decapitated at 1100 h, and serum gonadotropin levels were measured by RIA. Serum LH of the rats kept under LL was reduced to the level of the intact rats with the smaller testosterone dose (125 micrograms/day). Under all other lighting conditions only the large dose (250 micrograms/day) was able to restore the serum LH concentration to the level of the intact rats. Serum FSH was restored only partially, and the effect was the same with both doses and similar under all lighting conditions. We conclude that the increase in testosterone negative feedback sensitivity was not caused by the lack of periodicity of illumination alone, but that sufficient intensity of lighting throughout the 24 h was needed as well.     

Recommendations for daytime,evening, and nighttime indoor light exposure to best support physiology,sleep, and wakefulness in healthy adults

Ocular light exposure has important influences on human health and well-being through modulation of circadian rhythms and sleep, as well as neuroendocrine and cognitive functions. Prevailing patterns of light exposure do not optimally engage these actions for many individuals, but advances in our understanding of the underpinning mechanisms and emerging lighting technologies now present opportunities to adjust lighting to promote optimal physical and mental health and performance. A newly developed, international standard provides a SI-compliant way of quantifying the influence of light on the intrinsically photosensitive, melanopsin-expressing, retinal neurons that mediate these effects. The present report provides recommendations for lighting, based on an expert scientific consensus and expressed in an easily measured quantity (melanopic equivalent daylight illuminance (melaponic EDI)) defined within this standard. The recommendations are supported by detailed analysis of the sensitivity of human circadian, neuroendocrine, and alerting responses to ocular light and provide a straightforward framework to inform lighting design and practice.

Light exposure influences human health and wellbeing by modulating circadian rhythms and sleep. This Consensus View outlines the first expert scientific consensus recommendations for appropriate daily patterns of light exposure to promote health and wellbeing and inform lighting design and practice.     

Morphological Background Detection and Illumination Normalization of Text Image with Poor Lighting

In this paper, some morphological transformations are used to detect the unevenly illuminated background of text images characterized by poor lighting, and to acquire illumination normalized result. Based on morphologic Top-Hat transform, the uneven illumination normalization algorithm has been carried out, and typically verified by three procedures. The first procedure employs the information from opening based Top-Hat operator, which is a classical method. In order to optimize and perfect the classical Top-Hat transform, the second procedure, featuring the definition of multi direction illumination notion, utilizes opening by reconstruction and closing by reconstruction based on multi direction structuring elements. Finally, multi direction images are merged to the final even illumination image. The performance of the proposed algorithm is illustrated and verified through the processing of different ideal synthetic and camera collected images, with backgrounds characterized by poor lighting conditions.     

Chick pineal serotonin acetyltransferase: a diurnal cycle maintained in vitro and its regulation by light.

We have reproduced in vitro the diurnal cycles in levels of serotonin acetyltransferase activity found in the chick pineal gland in vivo. The more closely the lighting conditions of culture matched those under which the birds were raised, the closer was the similarity between cycles in levels of enzyme activity in vitro and in vivo. Repetitive cycles in levels of acetyltransferase activity persisted in culture for at least 4 days under a diurnal cycle of illumination, and at least 2 days in continuous darkness. When glands were explanted into culture in the light phase of a cycle, short periods of further exposure to light markedly stimulated subsequent increase of acetyltransferase in the dark (after a short lag). Prolonged exposure to light in culture markedly inhibited increase of enzyme activity. Cycles in the levels of enzyme activity in glands cultured under altered light cycles were regulated primarily by changes in illumination. However, the endogenous biological 'clock' remained at least partly entrained to the original light cycle. Increase of acetyltransferase activity in vitro was markedly stimulated by theophylline plus compound Ro. 20.1724 (4-(3-butoxy-4-methoxybenzyl)-2-imidazolidinone) under all lighting conditions. Kinetics (to the time of attaining maximum levels in situ) of the increase under diurnal lighting and in constant darkness were indistinguishable from those in vivo. A high concentration of dl-propranolol markedly stimulated an increase in acetyltransferase activity in glands cultured in constant darkness but had little effect on glands under diurnal lighting or continuous illumination.     

Scotopic illumination enhances entrainment of circadian rhythms to lengthening light:dark cycles

Endogenously generated circadian rhythms are synchronized with the environment through phase-resetting actions of light. Starlight and dim moonlight are of insufficient intensity to reset the phase of the clock directly, but recent studies have indicated that dim nocturnal illumination may otherwise substantially alter entrainment to bright lighting regimes. In this article, the authors demonstrate that, compared to total darkness, dim illumination at night (< 0.010 lux) alters the entrainment of male Syrian hamsters to bright-light T cycles, gradually increasing in cycle length (T) from 24 h to 30 h. Only 1 of 18 hamsters exposed to complete darkness at night entrained to cycles of T > 26 h. In the presence of dim nocturnal illumination, however, a majority of hamsters entrained to Ts of 28 h or longer. The presence or absence of a running wheel had only minor effects on entrainment to lengthening light cycles. The results further establish the potent effects of scotopic illumination on circadian entrainment and suggest that naturalistic ambient lighting at night may enhance the plasticity of the circadian pacemaker.     

The ecological impact of city lighting scenarios: exploring gap crossing thresholds for urban bats

As the global population urbanizes, dramatic changes are expected in city lighting and the urban form, which may threaten the functioning of urban ecosystems and the services they deliver. However, little is known about the ecological impact of lighting in different urban contexts. Movement is an important ecological process that can be disrupted by artificial lighting. We explored the impact of lighting on gap crossing for Pipistrellus pipistrellus, a species of bat (Chiroptera) common within UK cities. We aimed to determine whether the probability of crossing gaps in tree cover varied with crossing distance and lighting level, through stratified field surveys. We then used the resulting data on barrier thresholds to model the landscape resistance due to lighting across an entire city and explored the potential impact of scenarios for future changes to street lighting. The level of illumination required to create a barrier effect reduced as crossing distance increased. For those gaps where crossing was recorded, bats selected the darker parts of gaps. Heavily built parts of the case study city were associated with large and brightly lit gaps, and spatial models indicate movement would be highly restricted in these areas. Under a scenario for brighter street lighting, the area of accessible land cover was further reduced in heavily built parts of the city. We believe that this is the first study to demonstrate how lighting may create resistance to species movement throughout an entire city. That connectivity in urban areas is being disrupted for a relatively common species raises questions about the impacts on less tolerant groups and the resilience of bat communities in urban centres. However, this mechanistic approach raises the possibility that some ecological function could be restored in these areas through the strategic dimming of lighting and narrowing of gaps.     

Spectral properties of light affect plasma and pituitary gonadotropins in male rats

In order to find out whether different light spectra have any role in regulating the gonadotropin levels in male rats, we compared the 24-hour patterns of plasma and pituitary gonadotropins in rats kept for 7 days in natural or in cool white artificial lighting (exp. I). The intensity and periodicity of the two lighting conditions were adjusted as similar as possible. Further, we measured plasma and pituitary gonadotropins in the middle of the light period and in the middle of the dark period in rats kept for 7 days under artificial lightings of three different spectra (exp. II). In both experiments, in all lighting conditions we found higher plasma levels of LH and FSH during the dark than the light period. The differences were statistically significant only when the illumination contained more long and/or short wavelengths than the usual cool white laboratory lighting. The pituitary contents of gonadotropins were not found to vary with the periodicity of lighting. In the 24-hour patterns the overall plasma levels were higher and the pituitary contents of gonadotropins lower in natural lighting than in cool white lighting. It was concluded that the spectral properties of light influence the secretion of gonadotropins in male rats, but the mechanism involved remains to be clarified.     

Bandgap Engineering Enhances the Performance of Mixed‐Cation Perovskite Materials for Indoor Photovoltaic Applications

Indoor photovoltaics (IPVs) are attracting renewed interest because they can provide sustainable energy through the recycling of photon energy from household lighting facilities. Herein, the Shockley–Queisser model is used to calculate the upper limits of the power conversion efficiencies (PCEs) of perovskite solar cells (PeSCs) for two types of artificial light sources: fluorescent tubes (FTs) and white light–emitting diodes (WLEDs). An unusual zone is found in which the dependence of the PCEs on the bandgap (E_g) under illumination from the indoor lighting sources follows trends different from that under solar irradiation. In other words, IPVs exhibiting high performance under solar irradiation may not perform well under indoor lighting conditions. Furthermore, the ideal bandgap energy for harvesting photonic power from these indoor lighting sources is ≈1.9 eV—a value higher than that of common perovskite materials (e.g., for CH₃NH₃PbI₃). Accordingly, Br^? ions are added into the perovskite films to increase their values of E_g. A resulting PeSC featuring a wider bandgap exhibits PCEs of 25.94% and 25.12% under illumination from an FT and a WLED, respectively. Additionally, large‐area (4 cm²) devices are prepared for which the PCE reaches ≈18% under indoor lighting conditions.     

Guidelines for hurricane and disaster preparation for animal facilities

Animal facilities are vulnerable to hurricanes and other natural disasters, which can endanger lives and disrupt critical animal care routines. Facility managers must therefore prepare a rigorous emergency plan that ensures human safety while considering the specific needs of all animals on site. The author presents guidelines and recommendations for disaster preparedness based on her experience at a facility in Florida, where hurricanes are relatively common. An effective plan must include a priority system, a well-trained emergency response team, efficient communication methods and concrete provisions for animals and employees.     

Orientation of the snail Biomphalaria straminea (Dunker, 1848) in response to light in a situation of selection

The behavioral response of Biomphalaria straminea to light was evaluated in terms of location of the snail in a Y-shaped aquarium in a situation of selection and of the rate (cm/hour) and direction of locomotion under homogeneous (vertical) or differential (horizontal) lighting upon only one arm of the aquarium. The light source consisted of daylight fluorescent lamps with a spectrum close to that of natural light, with illumination varying from 2.8 to 350 lux. Analysis of the data showed that all animals, whether in groups or isolated, were attracted to light, although the time needed to approach the light source was 50% shorter for the former than for the latter. The rate of locomotion of B. straminea was 35% higher than that observed in B. glabrata and 51% higher than that observed in B. tenagophila studied under similar conditions. The results are discussed in terms of social factors and geographical distribution of the three species.     

The Influence of Very Low Illumination on the Postural Sway of Young and Elderly Adults

The purpose of the present study was to evaluate the influence of very low ambient illumination and complete darkness on the postural sway of young and elderly adults. Eighteen healthy young participants aged 23.8±1.5 years and 26 community-dwelling elderly aged 69.8±5.6 years were studied. Each participant performed four tests while standing on a force platform in the following conditions: in normal light (215 lx) with open eyes and with closed eyes, in very low illumination (0.25 lx) with open eyes, and in complete darkness with open eyes. The sequences of the tests in the altered visual conditions were determined by random blocs. Postural sway was assessed by means of the force platform measurements. The centre of pressure variables: the medio-lateral and antero-posterior path lengths, mean velocities, sway areas, and fractal dimensions were analysed. Very low illumination resulted in a statistically significant increase in postural sway in both the young and elderly groups compared to normal light, although the increase was significantly smaller than those observed in the eyes closed and complete darkness condition, and no significant effects of illumination on fractal dimensions were detected. The gains of the sways in the very low or no illumination conditions relative to the normal light condition were significantly larger in the group of young participants than in the group of elderly participants (up to 50% and 25%, respectively). However, the response patterns to changes in illumination were similar in the young and elderly participants, with the exception of the short-range fractal dimension of the medio-lateral sway. In conclusion, very low illumination resulted in increased postural sway compared to normal illumination; however, in the closed eye and complete darkness conditions, postural sway was significantly higher than in the very low illumination condition regardless of the age of the participants.     

A role for artificial night-time lighting in long-term changes in populations of 100 widespread macro-moths in UK and Ireland: a citizen-science study

The abundance of 100 of the most widespread species of macro-moth in the UK and Ireland was estimated from light-trap records reported to the UK and Ireland Garden Moth Scheme between 2005 and 2015. Recording sites were classified into low, medium and high night-time illumination categories by satellite imagery, into land-use types from the dominant use in the 1–2 km surrounding area, and by latitude. Most urban sites were in the group classified as having high night-time illumination. Comparison between medium and low night-time illuminated sites allowed differences between levels of illumination free from the effect of urbanization on moth abundance to be assessed. The medium and low night-time illuminated sites differed significantly in the frequency of grassland and arable land-use types and in geographic location with more grassland and north-western sites in the low-light category. After adjustment for these differences and for variations between taxonomic family groups, the medium to low night-time lighting abundance ratios explained a significant (P?<?0.001) 20% of the variance in long-term changes in moth abundance reported by the Rothamsted Insect Survey for the years 1968–2002. This is the first demonstration that artificial night-time lighting has had, in combination with other factors, a significant influence on levels of abundance of moth populations.     

A simple light-level recording device to monitor lighting in animal quarters

The performance of lighting timers in animal rooms was tested with a portable light-level recorder. The instrument monitored the light and dark phases under various degrees of illumination. This inexpensive method of electronic surveillance ensured the validity of experiments dependent on photoperiodicity.     

The effects of feedback lighting on the circadian drinking rhythm in the diurnal new world primate Saimiri sciureus

Feedback lighting provides illumination primarily during the subjective night (i.e., the photosensitive portion of the circadian cycle) in response to a given behavior. This technique has previously been used to test the nonparametric model of entrainment in nocturnal rodents. In three species (Rattus norvegicus, Mesocricetus auratus, and Mus musculus), the free-running period of the locomotor activity rhythm was similar whether the animals were exposed to continuous light or discrete light pulses occurring essentially only during the subjective night (i.e., feedback lighting). In the current experiments, feedback lighting was presented to squirrel monkeys so that light fell predominantly during the subjective night. Feedback lighting was linked to the drinking behavior in this diurnal primate so that when the animal drank, the lights went out. Despite the seemingly adverse predicament, the monkeys maintained regular circadian drinking rhythms. Furthermore, just as the period of the free-running activity rhythms of nocturnal rodents exposed to continuous light or feedback lighting were similar, the period of the drinking rhythms of the squirrel monkeys in continuous light and feedback lighting were comparable (25.6 +/- 0.1 and 25.9 +/- 0.1 hours, respectively), despite a substantial decrease in the total amount of light exposure associated with feedback lighting. The free-running period of monkeys exposed to continuous dark (24.5 +/- 0.1 hours) was significantly shorter than either of the two lighting conditions (P < 0.001). The results presented for the drinking rhythm were confirmed by examination of the temperature and activity rhythms. Therefore, discrete light pulses given predominately during the subjective night are capable of simulating the effects of continuous light on the free-running period of the circadian rhythms of a diurnal primate. The response of squirrel monkeys to feedback lighting thus lends further support for the model and suggests that the major entrainment mechanisms are similar in nocturnal rodents and diurnal primates.