Organic light-emitting diode (OLED) displays have been widely used in smartphones in recent years. Manufacturers use the stroboscopic visibility measure (SVM) to characterize and compare the performance of OLED displays using the pulse-width modulation (PWM) dimming method in producing perceivable flicker, although the SVM was developed for lighting products. This study investigated how the dimming frequency and display luminance of an OLED smartphone display affected the stroboscopic effect by presenting an oscillating arm in front of the display. The results showed that the stroboscopic effect was visible when the dimming frequency was 480 and 960 Hz with the display luminance below 40cd/m2, and when the dimming frequency was 1440 Hz, with the display luminance at 5cd/m2, the threshold of the duty cycle was around 50%. When the dimming frequency was 1920 or 2160 Hz, the stroboscopic effect was invisible. The results also suggested that for OLED displays, the SVM may still be used, but an SVM of 1.5 to 2 can be used as a conservative threshold instead under the experimental conditions.
Since visible light communication (VLC) uses light-emitting diode (LED) as transmitters, it has dual functions of illumination and communication. To meet flexible lighting and energy-saving needs, we propose a novel, to the best of our knowledge, dimming control scheme for spectrally efficient clipping-free multilayer optical orthogonal frequency division multiplexing (CFMO-OFDM)-based VLC systems. In order to achieve high dynamic-range dimming control for LEDs, the time-domain CFMO-OFDM signals are first grouped based on frequency-domain subcarrier distribution. Then, the periodic grouped direct current (DC) signal can be flexibly chosen and added to the above CFMO-OFDM signals. Simulation results demonstrate that, compared with classical asymmetrical hybrid optical OFDM (AHO-OFDM) and DC bias-based dimming methods, the proposed scheme offers higher dimming range, better flexibility, and lower implementation complexity, as well as superior bit error rate (BER) performance.
Photochromic smart windows with efficient solar heat and sunlight modulation are highly sought after for energy efficiency in buildings. However, the preparation of organic-inorganic hybrid photochromic coating with high transparency and excellent dimming ability remains a challenge. Here, we achieve a high dispersion of inorganic nanoparticles in the polymer network based on the B─O─W coordination bond locking strategy, and effectively reduce the energy band gap of Phosphotungstic acid (PTA) by adjusting the local coordination and electronic environment of the metal centre (W) to design a novel conjugated organic-inorganic hybrid photochromic material with high transparency (96.4%), rapid photoresponse (colouring in10 s), and excellent dimming ability (reaching saturation state in 20 min, Visible light modulation range △T550 nm = 87.1%, △T749 nm = 94.0%). Selective heating and cooling of interiors in winter and summer shows excellent potential for improving indoor sunlight comfort and increasing energy efficiency in buildings.
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To compare the clarity of images displayed on a 3D local dimming technology (LDT) monitor (LMD-XH550MT) to that on a conventional 3D monitor (LMD-X550MT) integrated into the Artevo 800® system. Laboratory investigation METHODS: Six vitreoretinal surgeons evaluated the clarity of the surgical field on photographs displayed simultaneously on 2 monitors during cataract and vitreous surgery by the Artevo 800® system. The visibility scores were made on a 5-point scale for images recorded during anterior capsulotomy, phacoemulsification, cortex aspiration, core vitrectomy, and peeling an epiretinal membrane or an internal limiting membrane (ILM). The skewness and kurtosis of the images during anterior and posterior segment surgery were evaluated. The mean visibility scores were significantly higher with the LDT monitor at 4.7±0.1 than with the conventional monitor at 2.9±0.1 (P<0.001). The visibility scores for anterior capsulotomy (P=0.034), phacoemulsification (P=0.036), cortex aspiration (P=0.036), core vitrectomy (P=0.035), peeling of epiretinal membrane (P=0.036), and ILM (P=0.036) were significantly higher with the LDT monitor than with the conventional monitor. The absolute value of skewness during anterior segment surgery was significantly lower with the LDT monitor (0.20±0.05) than with the conventional monitor (-0.44±0.06, P=0.03). Higher contrast with the LDT monitor was attained by adjusting the backlight brightness according to the brightness of the images, which provided better image clarity for 3D heads-up cataract and vitreous surgery.
Lighting systems account for a significant proportion of energy consumption in buildings. Therefore, energy conservation within these systems can greatly enhance overall building energy efficiency. This study proposes a control strategy for LED lamps by adjusting lighting intensity and improving the performance of electric luminaires. The approach involves implementing an automated dimming system that adapts lighting intensity based on surrounding light levels. A system comprising an ambient light sensor, microcontroller, power supply module, dimming controller, and lamp was developed. The sensors measure brightness within a specified range in real time, and the microcontroller analyzes and compares this data against the brightness settings for specific areas. The designed control system was tested in a laboratory setup to demonstrate its effectiveness in a controlled environment. Results showed a 75.65% reduction in power consumption compared to standard lamps in a simulated environment, highlighting its potential for significant energy savings in buildings and its contribution to environmental sustainability.
As the digital economy expands rapidly in modern cities, its influence on both urban growth and public health is increasingly significant. However, the concurrent rise of light pollution-now recognized as the fifth major source of environmental pollution-presents critical challenges, particularly to human health. Among the most vulnerable populations are seniors, whose cognitive function may be adversely affected by heightened nighttime lighting. On the one hand, the development of the digital economy can promote local medical and public health initiatives. On the other hand, cities with more developed digital economies often experience stronger night time lighting. This study investigates the dual impact of light pollution and digital economy growth on the cognitive health of seniors in China, leveraging data from the China Health and Retirement Longitudinal Survey (CHARLS) from 2013 to 2018, conducting a comprehensive analysis combining micro and macro data. By developing an enhanced digital economy index and employing grey relational analysis and serial multiple mediation models, this research explores the mechanisms through which both phenomena influence cognitive abilities in the elderly. Additionally, coupling coordination analysis and GIS technology are utilized to assess the spatial interactions and development dynamics across various prefecture-level cities. Findings reveal that the digital economy significantly improves cognitive functions by enhancing urban infrastructure and public health services. However, this growth simultaneously exacerbates light pollution through increased nighttime lighting, which undermines these positive effects. Additionally, the impact of light pollution on cognitive functions exhibits significant heterogeneity across cities with different levels of urbanization. Highly developed cities demonstrate poorer coordination between digital economic growth and light pollution management. This suggests that the pursuit of economic prosperity in these regions often overshadows effective environmental health measures. This study highlights the critical need for balanced and sustainable urban development strategies that leverage the benefits of the digital economy while mitigating the adverse effects of light pollution. Urban planners should incorporate light pollution management into broader urban development plans to ensure that economic advancements do not compromise environmental and public health, thereby supporting the sustainable development of livable cities.
This article proposes an improved Visible Light Communication (VLC) solution that, besides the indoor lighting and data transfer, offers an energy-efficient alternative for modern workspaces. Unlike Light-Fidelity (LiFi), designed for high-speed data communication, VLC primarily targets applications where fast data rates are not essential. The developed prototype ensures reliable communication under variable lighting conditions, addressing low-speed requirements such as test bench monitoring, occupancy detection, remote commands, logging or access control. Although the tested data rate was limited to 100 kb/s with a Bit Error Rate (BER) below 10-7, the key innovation is the light dimming dynamic adaptation. Therefore, the system self-adjusts the LED duty cycle between 10% and 90%, based on natural or artificial ambient light, to maintain a minimum illuminance of 300 lx at the workspace level. Additionally, this work includes a scalability analysis through simulations conducted in an office scenario with up to six users. The results show that the system can adjust the lighting level and maintain the connectivity according to users' presence, significantly reducing energy consumption without compromising visual comfort or communication performance. With this light intensity regulation algorithm, the proposed solution demonstrates real potential for implementation in smart indoor environments focused on sustainability and connectivity.
The coronavirus-induced disease 19 (COVID-19) pandemic, caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infections, has had a devastating impact on millions of lives globally, with severe mortality rates and catastrophic social implications. Developing tools for effective vaccine strategies and platforms is essential for controlling and preventing the recurrence of such pandemics. Moreover, molecular virology tools that facilitate the study of viral pathogens, impact of viral mutations, and interactions with various host proteins are essential. Viral replicon- and virus-like particle (VLP)-based systems are excellent examples of such tools. This review outlines the importance, advantages, and disadvantages of both the replicon- and VLP-based systems that have been developed for SARS-CoV-2 and have helped the scientific community in dimming the intensity of the COVID-19 pandemic.
Enhancing low-light images with natural colors poses a challenge due to camera processing variations and limited access to ground-truth lighting conditions. To address this, we propose Dimma, a semi-supervised approach that aligns with any camera using a small set of image pairs captured under extreme lighting conditions. Our method employs a convolutional mixture density network to replicate camera-specific noise present in dark images. We enhance results further by introducing a conditional UNet architecture based on user-provided lightness values. Trained on just a few real image pairs, Dimma achieves competitive results compared to fully supervised state-of-the-art methods trained on large datasets.
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Long-range synchrony in the frog retina has been reported to be accompanied by oscillations. In this study, we found novel long-range synchronous firing without oscillatory activities. Spatially correlated visual stimuli were presented to the frog retina, after which spike responses from dimming detectors were analyzed to investigate the correlated spike activities and receptive fields (RFs). The results revealed precise synchronous firing from both adjacent cell pairs with overlapping RFs and cell pairs with distant RFs of up to 1,500 µm apart, even in the absence of oscillatory activities. Clear double-peaked cross correlograms were not detected. A considerable number of cell pairs exhibited RFs estimated from the synchronized spikes predominantly overlapped with those of one of the original cell pairs, suggesting that such synchronous firing can encode redundant spatial information. These results indicated the existence of a long-range neural substrate that generates precise synchrony among dimming detectors in response to spatially correlated stimuli. As the coincident spikes provide strong synaptic input to downstream neurons, synchronized spikes among dimming detectors might contribute to reliable signal transmission in the tectum, in which multiple retinal ganglion cells converge onto a single neuron.NEW & NOTEWORTHY In this study, we identified a novel form of long-range synchronous firing-occurring without oscillatory activities-among frog retinal ganglion cells known as dimming detectors. Spatially correlated visual stimuli evoked precise synchronous firing, even between cells with nonoverlapping receptive fields (RFs). RFs estimated from synchronized spikes predominantly overlapped with one cell's RF, suggesting redundant spatial coding. This synchronous firing might enhance reliable signal transmission from the retina to the tectum.
Dimming control is an indispensable functionality for visible-light communication (VLC) that enables both illumination and data transmission. However, how to achieve both high-resolution dimming control and spectral-efficient communication is still an open problem. Therefore, a novel high-resolution dimmable augmented spectral-efficiency discrete multi-tone (HD-ASE-DMT) architecture is proposed in this paper. To address the limitation of low dimming resolution in a conventional pulse-width modulation (PWM) scheme, a hybrid PWM mechanism was first designed by combining the inter-symbol and intra-symbol PWM signals, which provided flexible and high-resolution two-tier dimming control. Furthermore, a reconstructed process was conceived to achieve the seamless integration of the hybrid PWM and the spectral-efficient ASE-DMT architecture. As a result, the proposed HD-ASE-DMT architecture maintains full compatibility with legacy ASE-DMT receivers, thus reducing the implementation complexity compared to the existing dimmable modulation schemes. Simulation results demonstrated that a two-orders-of-magnitude improvement in the dimming resolution was achieved by the HD-ASE-DMT architecture. Moreover, the spectral efficiency of the HD-ASE-DMT architecture was improved by 29.3% compared to the conventional scheme.
Artificial light at night (ALAN) marks the global impact of humanity1,2. Yet, our understanding of its true ebb and flow has been limited, often based on temporally aggregated satellite data that obscure finer dynamics. Here, using daily night-time satellite imagery3 and a continuous change detection approach4,5, we created global maps of high-frequency ALAN dynamics (2014-2022). Our findings challenge the prevailing perspective that changes in light radiance are largely gradual and unidirectional. Instead, the nightlights of Earth are surprisingly dynamic, characterized by frequent and coexisting brightening and dimming. On average, each location experiencing change underwent 6.6 distinct shifts over the 9 years. Driven by this volatility, the cumulative area of total ALAN change comprised 2.05 million km2 of abrupt changes and 19.04 million km2 of gradual changes. Brightening contributed a radiance increase equivalent to 34% of the 2014 global baseline, whereas dimming offset this by 18%. Notably, both brightening and dimming have markedly intensified over the past decade. This evidence of increasing volatility in human night-time activity provides an important dynamic dimension for understanding urban evolution, energy transitions, policy impacts and ecological consequences of rapidly changing illuminated nights.
Planula larvae of the reef-building coral Acropora millepora exhibit whole-body contraction and ciliary arrest in response to sudden light dimming. Quantitative behavioural assays revealed reduced swimming speed and changes in vertical and horizontal movement under alternating light and dark conditions. High-speed microscopy showed that ciliary activity ceases upon dimming, while the typically elongated body contracts into a rounded form, altering locomotion. This response reveals a coordinated motor output in a diffuse, non-centralised nervous system, consistent with neuropeptidergic signalling. We propose that it may contribute to regulating larval positioning within the structurally complex and heterogeneous light environment of reef habitats, a process critical for coral recruitment and survival.
Light pollution from artificial light at night (ALAN) is a significant environmental problem with far-reaching consequences for ecological systems. Recent innovations in light-emitting diode (LED) technology may offer sustainable outdoor lighting solutions, but scientific evidence is lacking. We investigated the effects of various LED lighting properties (color temperature, light intensity, and luminaire shape), individually and in combination, on flight-active and ground-dwelling arthropods. We therefore conducted a field experiment at 3 forest field sites in Switzerland with standardized LED streetlights. Over the course of 3 summers, we monitored flight-active insects and ground-dwelling arthropods with automated flight-interception and pitfall traps. The absence of light reduced the number of arthropods caught by 91%. However, when lighting was necessary, dimming lights by 50% and using focused luminaires resulted in reductions of 22% and 42%, respectively. Light color influenced arthropod responses only when combined with dimming. Our results underscore the ecological benefits of darkness and the complex interactions among lighting properties. An optimized combination of these properties, particularly well-focused and dimmed LED luminaires, represents a practical and effective measure to reduce the ecological impacts of ALAN and promote the conservation of nocturnal species. Mitigación del impacto de la contaminación lumínica sobre los artrópodos con base en las propiedades de los diodos emisores de luz Resumen La contaminación lumínica provocada por la luz artificial nocturna (LAN) es un problema ambiental importante con consecuencias de gran alcance para los ecosistemas. Las recientes innovaciones en la tecnología de diodos emisores de luz (LED) pueden ofrecer soluciones sustentables para la iluminación exterior, pero faltan pruebas científicas. Investigamos los efectos de diversas propiedades de la iluminación LED (temperatura de color, intensidad luminosa y forma de la luminaria), tanto individualmente como en combinación, sobre los artrópodos voladores y terrestres. Para ello, realizamos un experimento de campo en tres bosques de Suiza con focos LED estandarizados. Durante tres veranos, monitoreamos los insectos voladores y los artrópodos terrestres con trampas automáticas de interceptación de vuelo y trampas de caída. La ausencia de luz redujo el número de artrópodos capturados en un 91%. Sin embargo, cuando era necesario iluminar, la reducción de la intensidad de la luz en un 50% y el uso de luminarias enfocadas dieron lugar a reducciones del 22% y del 42%, respectivamente. El color de la luz solo influyó en las respuestas de los artrópodos cuando se combinó con la atenuación. Nuestros resultados subrayan los beneficios ecológicos de la oscuridad y las complejas interacciones entre las propiedades de la iluminación. Una combinación óptima de estas propiedades, en particular luminarias LED bien enfocadas y atenuadas, representa una medida práctica y eficaz para reducir los impactos ecológicos de la LAN y promover la conservación de las especies nocturnas. 夜间人工光源(artificial light at night, ALAN)造成的光污染是一项严重的环境问题, 并对生态系统具有深远影响。近期关于发光二极管(light emitting diode, LED)技术的创新成果可能为户外照明提供可持续解决方案, 但尚且缺乏相关的科学证据。本研究分析了LED照明特性(色温、光强和灯具形状)对活跃飞行和地面栖息的节肢动物的影响, 包括这些特性的单独作用和组合作用。为此, 我们在瑞士三个森林实验站点用标准化LED路灯进行了野外实验。我们在三个夏季利用自动飞行拦截陷阱和坑式陷阱监测了活跃飞行的昆虫和地面栖息的节肢动物。在无光条件下, 捕获到的节肢动物数量减少了91%。然而, 当必须使用照明时, 将灯光调暗50%和使用聚焦灯具可分别导致捕获量减少22%和42%。色温仅在调暗亮度的情况下才会影响节肢动物的反应。我们的研究结果强调了黑暗的生态效益以及照明特性之间的复杂相互作用。这些特性的最优组合(特别是高度聚焦且调暗的LED灯具), 可作为一项实用且有效的措施, 来减少ALAN的生态影响并促进对夜行性物种的保护。【翻译:胡怡思;审校:聂永刚】.
Traditional polymer-dispersed liquid crystal (PDLC) faces limitations in smart dimming applications due to high driving voltage and poor high-temperature stability. In this study, a high-birefringence liquid crystal (QYPDLC-901) was used to prepare PDLC films with liquid crystal contents ranging from 72 wt% to 80 wt%, achieved through synergistic regulation of a low-functional acrylic polymer system and a low-intensity curing process. The effects of liquid crystal content, cell gap, and temperature on electro-optical properties were systematically investigated. Optimal performance was obtained at a liquid crystal content of 77 wt%, with a low threshold voltage of 2.9 V, saturation voltage of 7 V, fast response (rise time 4.2 ms, decay time 47 ms), and a favorable balance between high on-state and low off-state transmittance. Microstructural analysis revealed that the superior performance results from uniform droplet dispersion and low interfacial energy. Furthermore, the PDLC exhibited excellent switching stability from 23 °C to 90 °C, maintaining a maximum transmittance of 93% at 90 °C, with increases of only 0.4 V in threshold voltage and 0.1 V in saturation voltage. This study provides an experimental basis for designing smart dimming devices suitable for low-voltage driving and extreme environments.
We assess the impact of two solar radiation management (SRM) approaches, stratospheric aerosol injection (G6Sulfur) and solar radiation dimming (G6Solar), on SSP5-8.5-projected changes in summer monsoon precipitation across Afro-Asia for the mid-future (2040-2069) and far-future (2070-2099) periods, using Geoengineering Model Intercomparison Project (GeoMIP) experiments under CMIP6. Relative to SSP5-8.5, both SRM methods increase consecutive wet days (CWD), largely due to an enhanced increase in light-to-moderate precipitation rates (0.1-10 mm/day). Heavy precipitation (>10 mm/day) decreases across all three monsoon regions, leading to widespread reductions in mean precipitation, precipitation variability, and very heavy precipitation extremes (RX5day, R95pTOT), with far-future decreases nearly twice as large as those in the mid-future. Moisture budget diagnostics show that SRM-induced reductions in mean precipitation are driven primarily by a weakened vertical thermodynamic term, linked to reduced specific humidity resulting from SRM-induced cooling. Furthermore, SRM modifies projected precipitation seasonality. In the mid-future, precipitation onset is delayed by ∼3 days over most regions, while heterogeneous shifts in cessation result in little net change in season length. By contrast, in the far-future, earlier onset and later cessation lead to an extension of the precipitation season by up to ∼5 days. Urban and rural population exposure to wet and dry extremes decreases substantially under both SRM methods, except over South Asia and West Africa, where exposure to CWD increases. Overall, both G6Solar and G6Sulfur show potential to reduce the SSP5-8.5-induced intensification of Afro-Asian monsoon precipitation, while producing notable spatial and temporal heterogeneity in the monsoon response.
Syncope in athletes with hypertrophic cardiomyopathy (HCM) requires careful evaluation, as etiologies range from benign to life-threatening. Guidelines emphasize individualized risk stratification and shared decision-making. A 20-year-old basketball player experienced a syncopal episode when rising from a seated position, preceded by progressive lightheadedness and visual dimming, without chest discomfort or palpitations. Electrocardiogram abnormalities prompted further imaging, confirming the diagnosis of apical HCM. Evaluation demonstrated no left ventricular outflow tract obstruction at rest or with maximal-effort stress testing, and no exertional arrhythmias were observed. The episode was attributed to orthostatic syncope in a preload-dependent structurally abnormal left ventricle. He continued sports participation with hydration counseling, annual imaging, rhythm monitoring, and genetic evaluation, without recurrent events. This case highlights the importance of accurately identifying the etiology of syncope in athletes with HCM and supports individualized, risk informed sport participation rather than universal restriction. Syncope in athletes with HCM warrants comprehensive evaluation and tailored return-to-play decisions.