Effect of changing mesopic and photopic light conditions on visual functions

AIM:To determine the effects of change in light conditions on refractive error and visual functions including visual acuity,stereopsis and contrast sensitivity.METHODS:This cross-sectional study was conducted in the optometry clinic of the Shahid Beheshti School of Rehabilitation on 48 students in 2021-2022.All of them had eye health and normal visual function and could have refractive errors or not.Light intensity of 4 lx was considered equivalent to photopic light condition and light intensity of 1 lx was considered to be equivalent to mesopic light condition.The amount of refractive error was checked by auto refractometer and its changes in mesopic light condition were subjectively measured.Also,visual acuity,stereopsis and contrast sensitivity(in five spatial frequencies of 1.5,3,6,12,and 18 cycles per degree),were measured first in photopic light condition and then in mesopic light condition,by Snellen control vision chart,stereo butterfly test and the M&S technology monitor test respectively.RESULTS:In the 48 student subjects with an average age of 22.69±3.56y,mean of refractive error as sphere equivalent,visual acuity and stereopsis were-1.25±1.74 diopters,0 logMAR,44.37±13.03 seconds of arc,respectively in photopic light condition while in mesopic light was equal to-1.56±1.75 diopters,0.12±0.09 logMAR and 50.62±33.35 seconds of arc,respectively.The mean of contrast sensitivity measured at spatial frequencies of 1.5,3,6,12,and 18 cycles per degree in photopic condition was equal to 2.38±0.04,2.37±0.07,2.04±0.21,1.27±0.32,0.82±0.27 logarithm of contrast sensitivity,respectively and in mesopic lighting condition was equal to 2.34±0.12,2.30±0.16,1.84±0.28,1.02±0.28,0.63±0.24 logarithm of contrast sensitivity,respectively.Statistical analysis showed a significant difference between the two lighting conditions in all evaluated variables[refractive error(P<0.001),visual acuity(P<0.001),stereopsis(P=0.008)and contrast sensitivity(P<0.001)].CONCLUSION:The refractive error of the student subjects in mesopic light condition change towards myopia,and its amount is clinically significant.Also,the examination and comparison of the factors of visual acuity,stereopsis and contrast sensitivity in these two lighting conditions show that the decrease in brightness level to the mesopic level causes a decrease in the aforementioned visual functions.

Light intensity regulates the sexual behaviors of oriental fruit fly Bactrocera dorsalis under laboratory conditions

The oriental fruit fly,Bactrocera dorsalis(Hendel),is a devastating pest of citrus fruits.After successful mating,adult females insert their eggs into the ripened fruit,resulting in moldy and rotten fruit and causing great economic losses for the citrus industry.In the field,flies initiate copulatory behaviors as twilight approaches,and decreasing light intensity in this period is the normal stimulus for copulation.In this study,ten light intensities ranging from 0–30000 lux were set to identify the typical intensity that strongly regulates the copulation behavior of B.dorsalis.Three light intensities found to regulate the copulation behavior were then selected to verify their effects on adult male wing fanning and female chemotaxis towards 2,3,5-trimethylpyrazine(TMP).At last,strong light and complete darkness were artificially combined in the lab to verify whether they could prevent copulation to inform behavioral manipulation of oriental flies in the future.The results indicated that adult flies generally initiated copulatory behaviors at low light intensity(<1000 lux).Stronger light significantly prevented copulation in proportion to intensity,with nearly no copulation events initiated when light intensity was above 20000 lux.Both male wing fanning and female chemotaxis towards TMP were attenuated as light intensity became stronger.However,at 10000 lux,males still fanned their wings to a certain extent while TMP completely lost its attractiveness to females.In the darkness,adults did not initiate any sexual behaviors,e.g.,copulation,wing fanning,or chemotaxis to TMP.One hour of strong light(10000 lux)combined with continuous darkness completely prevented mating.These results show that light condition is an essential factor for copulatory behaviors in the oriental fruit fly.Researchers could thus manipulate light conditions artificially or disrupt the molecular target in flies’light transduction pathway to develop environmentally-friendly techniques to control this pest.

Light matters:Nest illumination alters egg rejection behavior in a cavity-nesting bird

Egg discrimination by cavity-nesting birds that build nests under dim light conditions was presumed to depend on nest luminance,although this hypothesis has rarely been tested.Tests of egg discrimination ability by cavity-nesting tits under dim light conditions may reveal the selection pressure from brood parasitism that they encounter under natural interactions.We manipulated the intensity of luminance of nests of the Green-backed Tit(Parus monticolus),a potential cuckoo host that possesses a strong discrimination ability of non-mimetic foreign eggs.We performed experiments to test their egg discrimination ability under different light conditions.Our results showed that Green-backed Tits discriminate against non-mimetic foreign eggs under normal light conditions in nest boxes,and this ability persisted at nest luminance as low as 4.78±1.31 lux that is several times lower than normal luminance(38.11±24.02 lux).However,egg discrimination by Green-backed Tits disappeared when nest luminance was reduced to a minimum of 0.35±0.15 lux.The latter value represents total darkness for humans.The present study shows that nest luminance plays a key role in egg discrimination by Green-backed Tits that build nests under dim light conditions.This study provides strong experimental evidence for nest illumination altering egg rejection behavior in cavity-nesting birds.

Impact of Different Light Characteristics on the Growth and Lipid Content of Diatom Phaeodactylum tricornutum Transconjugant Strains

Light regulates important metabolic processes in microalgal cells, which can further impact the metabolism and the accumulation of biomolecules such as lipids, carbohydrates, and proteins. Different characteristics of light have been studied on various strains of the model diatom Phaeodactylum tricornutum, but not on transconjugant cells and information on wild-type strains is still limited. Therefore, we studied the impact of different light characteristics such as spectral quality, light intensity and light shift on the growth, and the composition in lipids and fatty acids of P. tricornutum cells to provide a comprehensive context for future applications. Initially, we tested the impact of spectral quality and light intensity on P. tricornutum transformed with an episomal vector (Ptev), harboring the resistance gene Sh ble. Results indicated that Ptev cells accumulated more biomass and overall lipids in spectral quality Red 1 (R1: 34% > 600 nm > 66%) more effectively as compared to Red 2 (R2: 8% > 600 nm > 92%). It was also detected that cell granularity was higher in R1 as compared to R2. Furthermore, by testing two light intensities 65 μmol·m-2·s-1 and 145 μmol·m-2·s-1 light, it was observed that 145 μmol·m-2·s-1 led to an increase in growth trend, total biomass and lipid content. Combining spectral qualities and light intensities, we show that the lipid accumulation raised by 2.8-fold. Studying the light intensity and spectral quality allowed us to optimize the light conditions to R1 spectral quality and light intensity 145 μmol·m-2·s-1. These initial results showed that red light R1 at 145 μmol·m-2·s-1 was the best condition for biomass and total lipids accumulation in Ptev cells. Next, we further combined these two-light optimizations with a third light characteristics, i.e. light shift, where the cultures were shifted during the early stationary phase to a different light environment. We studied Red light shift (Rs) to investigate how light condition variations impacted P. tricornutum transconjugants Ptev and with an episomal vector containing the reporter gene YFP (PtYFP). We observed that Rs induced growth and fatty acid eicosapentaenoic acid (EPA) in Ptev as compared to PtYFP. Altogether, the study shows that red light shift of R1 at 145 μmol·m-2·s-1 promoted biomass and total lipids accumulation in Ptev and PtYFP cells. The study provides a comprehensive approach to using different light characteristics with the aim to optimize growth and lipids, as well as to fatty acid production.

Effects of Light and Temperature on Uptake andDistribution of Nitrogen, Phosphorus and Potassiumof Cucumber in Solar Greenhouse

The influence of light and temperature conditions inside solar greenhouse of winter-spring and autumn-winter crop in northern China on uptake and distribution of nitrogen. phosphorus and potassium of cucumber was studied. The results showed that plant root development and uptake and distribution of N, P and K benefited more from inside light and temperature changes in winter-spring crop. Root volume and root activity increased more rapidly in winter-spring than in autumn-winter. Uptake of total N, P2O5 and K2O increased with plant development in winter-spring, and declined in autumn-winter crop. Distribution of total N, P2O5 and K2O at different part of cucumber at fruit bearing stage was significantly influenced by inside light and temperature of solar greenhouse. Total N, P2O5 and K2O were mainly distributed to leaves and stems at early stage, and increasingly to fruits after fruit bearing.

关于消防员电梯的几点思考

结合相关规范条文,针对电气设计人员对于消防员电梯井道照明、机房空调配电及五方通话等方面存在的疑惑或争议进行探讨,并提出笔者的见解。

我国住宅建筑节能潜力分析——除供暖外的住宅建筑能耗

城镇民用建筑能源消耗分为北方地区供暖能耗、除供暖外的住宅能耗、除供暖外的一般性非住宅民用建筑和大型公共建筑能耗四部分,着重分析了其中的除供暖外的住宅能耗。首先,阐述了我国住宅建筑能耗的现状,指出目前我国住宅建筑能耗水平较低,但呈现加速增长的趋势;其次,针对我国住宅建筑能耗的刚性增长趋势,提出了住宅建筑节能的重点——住宅空调器升级与更新、降低照明能耗和减少家电待机损失。并分析计算了三个方面的节能措施所能达到的实际节能效果。

基于视觉识别的教室智能节能控制系统研究

为了解决高校教室照明和空调粗放管理造成的能源浪费和后勤管理成本增加的问题,基于人数视觉识别技术,设计一种教室智能节能控制系统。通过校园以太网和无线通信实现系统终端和服务器的数据对接,基于视觉识别算法搭建教室控制器,实现对教室照明模块、空调模块、显示模块和语音模块的智能节能控制。试验结果表明:10间教室的识别模块平均精确率在91.2%以上,人数判断精确性较高;单间教室识别模块全天精确率平均值为95.0%,标准差为3.52%,其稳定性较高;教室照明和空调联动控制管理策略,能有效解决教室自习或无人情况下照明和空调的使用管理,对提高高校教学楼管理人员工作效率、降低人力投入成本和推进后勤信息化智能化建设均有着重大的作用。

基于CAN总线照明和空调智能控制系统设计

介绍了建筑照明节能方案,设计了一种基于CAN总线的建筑照明和中央空调智能集中控制系统,并对该系统的工作原理和软硬件进行了讨论和探索。该系统可以有效实现对照明系统和中央空调系统的智能控制和节能。

移动式冷气机在585 nm强脉冲光治疗面部毛细血管扩张术后的应用评价

目的观察移动式冷气机在585 nm强脉冲光(IPL)治疗面部毛细血管扩张术后护理的效果与应用评价。方法选取2020年1—10月在中国人民解放军第四军医大学第二附属医院进行585 nm IPL治疗的48例面部毛细血管扩张病人作为研究对象,根据术后处理方式不同,采用随机抽签法分为冷气机组和冰袋冷敷组。对两组病人术后冷疗护理前后舒适状况及疼痛进行评分和对比。结果两组病人治疗后即刻疼痛感、红斑水肿评分均差异无统计学意义(P>0.05);术后30 min,两组间疼痛灼热感评分,冰袋冷敷组均值低于冷气机组,但差异无统计学意义(P>0.05);两组间红斑、水肿评分差异无统计学意义(P>0.05);冷敷护理后12 h,两组病人疼痛、灼热,水肿、红斑均明显消退,两组间VAS评分差异无统计学意义(P>0.05)。冷疗结束后,冷气机组舒适度75%(18/24)明显高于冰袋冷敷组33.3%(8/24),差异有统计学意义(P<0.05)。结论对585 nm IPL治疗后病人采用移动式冷气机进行冷敷降温护理,其止痛效果好,病人舒适度高,值得临床广泛应用推广。

Three‐terminal perovskite/integratedbackcontactsilicon tandem solar cells under low light intensity conditions

The current climate and energy crisis urgently needs solar cells with efficiencies above the 29% single junction efficiency bottleneck.Silicon/perovskite tandem solar cells are a solution,which is attracting much attention.While silicon/perovskite tandem cells in 2-terminal and 4-terminal configurations are well documented,the three-terminal concept is still in its infancy.It has significant advantages under low light intensities as opposed to concentrated sunlight,which is the critical factor in designing tandem solar cells for low-cost terrestrial applications.This study pre-sents novel studies of the sub-cell performance of the first three-terminal perovskite/silicon selective band offset barrier tandem solar cells fabricated in an ongoing research project.This study focuses on short circuit current and operating voltages of the subcells under light intensities of one sun and below.Lifetime studies show that the perovskite bulk carrier lifetime is insensitive to illumination,while the silicon cell's lifetime decreases with decreasing light intensity.The combination of perovskite and silicon in the 3T perovskite-silicon tandem therefore reduces the sensitivity of V_(OC) to light intensity and maintains a relatively higher V_(OC) down to low light intensities,whereas silicon single-junction cells show a marked decrease.This technological advantage is proposed as a novel advantage of three-terminal perovkite/silicon solar cells for low light intensities of one sun or less.

空调白色面板ABS材料光老化研究

采用家电行业常用的人工加速光老化实验方法,对目前空调面板常用的白色ABS材料进行了光老化研究,一方面比较了色母料和改性料方案的耐光老化性能,另一方面比较了常用光老化试验方法严酷程度。研究表明:改性料方案耐光老化性能优于色母料;采用氙灯光老化(X)、紫外光老化UVA(ZA)和紫外光老化UVB(ZB)等三种常用试验方法时,实验样品对光老化的响应程度依次为:UVB(ZB)测试>UVA(ZA)测试>氙灯(X)测试。

全新风管道机的设计探讨

在普通型风管送风式空调产品的基础上,通过重新设计计算,改进产品的控制逻辑。采用"小风量大焓差"的设计理念及对极端工况的处理,设计出全新风管道机系列产品。经过一系列试验,对许多疑问进行排除,解决设计中遇到的问题,将产品投入生产。

光伏直驱变频离心机中发电与耗电实验研究

光伏直驱变频离心机的最大特点是直接利用太阳能的直流电,通过直驱方式可减少DC/DC、DC/AC转换的损耗,提高能源利用率。本文通过对光伏组件的发电特性和光伏直驱变频离心机的耗电特点进行研究,提出两种控制方法,保证最大限度的利用太阳能,提高太阳能直驱利用率。

壁挂空调内机面板显示研究及应用

针对家用空调器内机面板显示的创新,从灯显到数显、LCD、LED显示,从显性显示到隐形显示,随着面板的发展外观显示不断推陈出新,以人性化为主、以新颖的外观显示,家用空调已不仅仅是普通的家用电器,更多的成为时尚家居的象征。

基于主断面分析法的轻薄体量仪表板工程可行性研究

为解决仪表板轻薄体量工程可行性问题,提升仪表板造型体量感染力。通过主断面分析法,找到影响仪表板轻薄体量的核心工程约束因素。分析表明:目前主机厂常用的传统空调因自身结构包络及布置位置占用了仪表板Y0和副驾驶侧空间,同时因副驾驶侧仪表板下边缘到地毯的距离要满足脚部空间要求,空调的布置位置不能降低,关联影响了Y0处仪表板的体量厚度。通过选用中置式的空调,空调仅占用仪表板Y0处,不仅打破了传统空调对副驾侧的限制,而且可以充分利用中置空调和地板之间的空间,将中置空调布置位置降低,给空调和仪表板上部大面之间布置的风道等零件提供足够的空间来实现仪表板上部大面降低,从而实现仪表板的轻薄体量。

天津市建筑节能推广中心电气节能设计

介绍了天津市建筑节能推广中心的供配电系统、照明系统的节能设计以及电力监控系统、空调自控系统、电动遮阳窗帘控制系统、太阳能发电监控系统在该项目中的应用。通过比较运行以来不同用电分项年电能消耗(万kWh)、折标煤量(吨标准煤),分析了工程节能效果。

Measuring light spectrum as a main indicator of artificial sources quality

Objective:To compare different artificial light sources in different places where plant breeding is conduced.Methods:Measurements were conducted outdoor,in room,in greenhouse,under four panels with light emitting diodes,in phytotron,in dark room with various light sources and inside Sanyo versatile environmental chamber.The measurements were made by using SpectraPen SP100(PSI,Czech Republic)device.Results:Our result showed that spectrum measured outdoor during sunny day had only one peak at the wavelength of 485 nm(ca.60000 relative units).On cloudy day,the trend of light spectrum curve was similar,but with lower values.At room conditions,the curve was more flat than outdoor.Under greenhouse conditions,the curve was similar to that measured outdoor.A few additional peaks on the curve appeared by adding high pressure sodium lamp.There were changes of curve under LED panels.Conclusions:It must be underlined that the most similar spectrum curve to daylight light has incandescent bulb and this light source should be preferred as support of daylight in greenhouses and as main source in phytotrons.Using high pressure sodium lamp in greenhouses as support of daylight cause increase in the red/far-red ratio and occurrence of a new peak on spectrum curve.The new possibilities are creating by LED panels with red and blue diodes.

Egg rejection based on egg size recognition as a specific strategy against parasitic cuckoos

In the coevolutionary interactions between avian brood parasites and their hosts,egg recognition based on color and/or pattern is a common and effective defense to counter parasitism.However,for egg recognition based on size,only a few studies have found affirmative results,and they do not provide unambiguous evidence that egg size recognition in hosts has evolved as an important and specific anti-parasite adaptation against parasite eggs.We studied the brood parasite system between the Asian emerald cuckoo Chrysococcyx maculatus and its host,the chestnut-crowned warbler Phylloscopus castaniceps.The cuckoo parasitizes the warbler using non-mimetic and larger eggs at a parasitism rate of 12.9%.The warbler nests used in this experiment were built in a dark environment with the nest illuminance near 0 lux.Experiments with 2 types of model eggs with colors and patterns resembling cuckoo eggs of different sizes(cuckoo egg size or host egg size)showed that the warblers were able to reject 63.6%of cuckoo model eggs under these dim light conditions.However,model eggs with the same color and pattern similar to the warbler egg size were always accepted.This study provides strong evidence supporting the theory that egg size recognition can be evolved in hosts as a specific anti-parasite adaptation against cuckoos.We suggest that the egg size recognition of the warbler is an outcome of the tradeoff between the costs of violating the parental investment rule and suffering cuckoo parasitism.