Winter Sunlight Research Articles

A Colored Temperature‐Adaptive Cloak for Year‐Round Building Energy Saving

AbstractAchieving year‐round energy savings in buildings holds great significance toward reaching carbon neutrality and sustainability. Switchable thermal‐management materials offer an energy‐free solution to dynamically regulating internal building temperatures, by passively emitting heat into cold outer space in summer, and absorbing heat from hot sunlight in winter. In addition to dynamic thermal regulation, color display is another pursuit for addressing aesthetic considerations; however, most current dynamically switchable materials lack color options, due to an optical conflict between adaptive solar reflection and selective visible absorption, limiting their wide adoption in aesthetic scenarios such as commercial exterior walls. Herein, a colored temperature‐adaptive cloak (CTAC) that achieves dynamically switchable thermal management in an energy‐neutral way without sacrificing year‐round vibrant color display is reported. This is realized by decoupling solar reflectivity modulation and color display through the choice of two individual constituent components, including thermochromic microcapsules, and fluorescent dyes. Moreover, compared to single‐mode samples with similar colors, the CTAC with dual modes stays 5.6–3.4 °C warmer during cold winter and 14.9–7.9 °C cooler during hot summer (peak solar irradiance: ≈735 and 1030 W m−2, respectively), exhibiting a remarkable potential to achieve year‐round building energy savings.

Research on the Current Status of Light Supplementation Technology for Dragon Fruit

Dragon fruit has a good market prospect for its good taste and high nutritional value. At the same time, since its planting conditions are easy to meet, dragon fruit is widely planted in many regions of China. However, the problem of insufficient sunlight in spring and winter still leads to an insufficient supply of dragon fruit production. To improve the quality as well as the annual supply cycle of dragon fruit fresh fruit, and improve the economic benefits of dragon fruit cultivation, fruit growers generally use artificial light supplementation technology to regulate the flowering cycle of dragon fruit to prolong the production period. This paper reviews the impact of different light qualities, light intensities, and photoperiod on the production and quality of dragon fruit, and summarizes the shortcomings of the existing supplementation technology. The feasibility of the combination of photovoltaic, energy storage, and dragon fruit light supplementation technology is also comprehensively analyzed, and the outlook is put forward, aiming to provide a direction for the further development of dragon fruit light supplementation technology.

Three birds with one stone strategy: A tri-modal radiator based on the cooling-compensation-heating effect

Passive radiative using solar energy for energy gain is receiving increasing attention as a green and sustainable energy supply method. However, passive radiative designs of existing materials are usually static and unsuitable for dynamic seasonal and weather changes. Here, we explore an efficient design of a temperature-adaptive thermal management sandwich structure that integrates passive daytime radiative cooling/heating and temperature control of phase change materials. Compared with conventional passive radiators, the developed phase change material-enhanced radiative cooler/heater (PDHM) can be flipped to adjust thermal management performance according to seasonal and diurnal temperature changes. The radiative cooling layer (PDRC) has a high solar reflectance (95%) and a high infrared emissivity (97%). The phase change layer (PCM) acts as an effective compensation for temperature, causing the PDRC cooling power to rise and fall by 15 W·m−2 during daytime and nighttime. The radiative heating layer (PDRH) has a low infrared emissivity (75.6%) and a high solar absorptivity (85.7%). The final PDHM aerogel achieves 11 °C below ambient temperature and 25 °C above ambient temperature under direct sunlight in summer and winter, and it leads to an increase in the average nighttime temperatures of 2.1 °C and 1 °C in summer and winter, reducing the diurnal temperature difference. Thus, the temperature-adaptive PDHM shows great potential for passive radiative regulation, which can further extend the application of passive radiators.

Bio-Based Waterborne Poly(Vanillin–Butyl Acrylate)/MXene Coatings for Leather with Desired Warmth Retention and Antibacterial Properties

This study presents a solvent-free, facile synthesis of a bio-based green antibacterial agent and aromatic monomer methacrylated vanillin (MV) using vanillin. The resulting MV not only imparted antibacterial properties to coatings layered on leather, but could also be employed as a green alternative to petroleum-based carcinogen styrene (St). Herein, MV was copolymerized with butyl acrylate (BA) to obtain waterborne bio-based P(MV–BA) miniemulsion via miniemulsion polymerization. Subsequently, MXene nanosheets with excellent photothermal conversion performance and antibacterial properties, were introduced into the P(MV–BA) miniemulsion by ultrasonic dispersion. During the gradual solidification of P(MV–BA)/MXene nanocomposite miniemulsion on the leather surface, MXene gradually migrated to the surface of leather coatings due to the cavitation effect of ultrasonication and amphiphilicity of MXene, which prompted its full exposure to light and bacteria, exerting the maximum photothermal conversion efficiency and significant antibacterial efficacy. In particular, when the dosage of MXene nanosheets was 1.4 wt%, the surface temperature of P(MV–BA)/MXene nanocomposite miniemulsion-coated leather (PML) increased by about 15 °C in an outdoor environment during winter, and the antibacterial rate against Escherichia coli and Staphylococcus aureus was nearly 100% under the simulated sunlight treatment for 30 min. Moreover, the introduction of MXene nanosheets increased the air permeability, water vapor permeability, and thermal stability of these coatings. This study provides a new insight into the preparation of novel, green, and waterborne bio-based nanocomposite coatings for leather, with desired warmth retention and antibacterial properties. It can not only realize zero-carbon heating based on sunlight in winter, reducing the use of fossil fuels and greenhouse gas emissions, but also improve ability to fight off invasion by harmful bacteria, viruses, and other microorganisms.

Thermal performance study of multiple thermal insulating glazings with polycarbonate films as interval layers

With the development of global economy, the proportion of energy consumption in buildings is increasing to approximately 40% total energy consumption. The glazed window system, which is the weakest part in the building envelopes, remarkably contributes to energy loss. Scholars and manufacturers are constantly working to improve the thermal properties of glass, such as Low-E glass, aerogel glass, vacuum glass, and so on. However, the advanced glazing either shades the sunlight in winter, or is too expensive to be widely used. In this paper, polycarbonate films with high transparency are used as the interval layers of double glazing, which not only have better thermal properties and visible light transmittance in winter, but also are less expensive to be used. The structures and thermal properties of multiple thermal insulating glazing with polycarbonate films (MTIGP) are systematically investigated. The U-values of MTIGP can be achieved from 1.5 to 2.0 W/m2·K with high transmittance of visible light (Tvis, 60–70%), when compared with a typical Low-E double glazing system (U-value, around 2.0 W/m2·K; TVis, around 60%), even lower when argon (Ar) or krypton (Kr) is used instead of air. The Solar Heat Gain Coefficient (SHGC) of MTIGP is higher than that of a typical Low-E double glazing system, which means more sunlight transmitting into the glazing system in winter to keep the rooms warmer. MTIGP and double silver Low-E pane are simulated with EnergyPlus, the results shows that energy consumption of MTIGP is better than that of double silver Low-E pane. The developed glazing system is expected to be used in severe cold and cold climate zones to improve thermal insulation and sunlight transmittance to reduce energy consumption.

Enhanced electron channel via the interfacial heterotropic electric field in dual S-scheme g-C3N4/WO3/ZnS photocatalyst for year-round antibiotic degradation under sunlight

Widespread and persistent presence of antibiotic contaminants in natural aquatic environments has aroused all mankind concern due to their potential threat to human health. Photocatalysis represents a promising means to remediate polluted waters with the simple assistance of solar energy. In this context, the feasibility of treating antibiotic contaminated water with g-C3N4/WO3/ZnS dual S-scheme heterojunction driven by interfacial heterotropic electric field was investigated under year-round climate conditions. The optimum composite (5-CWZ) could degrade >85% of tetracycline within 1 h of summer sunlight and 1.5 h of winter sunlight irradiation. The results of electron spin resonance (ESR), chemical trapping experiment, High performance liquid chromatography mass spectrometry (HPLC-MS), ultraviolet photoelectron spectroscopy (UPS) and density functional theory (DFT) calculation reflected that in-situ anchoring of WO3 and ZnS on the surface of g-C3N4 facilitates the formation of interfacial heterotropic electric field which were effective towards low-resistance charge carrier channelization, resulting sufficient •O2–, h+, •OH species evolving for attacking the active atoms of contaminants with high Fukui index. Furthermore, the retention of superior photocatalytic properties in complex actual water matrices together with the non-toxicity of both 5-CWZ photocatalyst and treated TC solution proved by Pisum sativum bud radicle elongation and bacterial (E. coli and B. subtilis) cultivation further demonstrated the feasibility of the 5-CWZ to treat antibiotics in real water under irradiation of solar light.

DS-guided deposition of PEDOT onto silk fabrics for rapid photothermal antibacterial and respiratory sensing

Polystyrene sulfonic acid is widely utilized as an effective template for synthesis of poly (3,4-ethylenedioxythiophene) (PEDOT), but the bonding fastness between PEDOT and textiles is unsatisfactory, which easily leads to poor conductivity. In this study, a linear template of dextran sulfate (DS) was covalently grafted onto silk fibers (SF), followed by in-situ deposition of PEDOT onto the silk fabrics, aiming at constructing a functional silk fabric with rapid photothermal antibacterial ability and durable flexible sensing performance. Impressively, the composite fabric of SF-g-DS/PEDOT exhibits excellent photothermal conversion performance and can rise to 80 °C within 1 min of irradiation with the light intensity of 100 mW/cm2, and can kill 99.99% of Escherichia coli (E. coli) on the fabric surface. Benefited from the strong interaction forces between the conductive polymer and silk fibers, the SF-g-DS/PEDOT fabric can still reach 75 °C after 15 times of washing, and achieves a 99.4% bactericidal rate against E. coli. In a relatively weak winter sunlight, the surface temperature of SF-g-DS/PEDOT can also be raised to 45 °C to keep the human body warm. Meanwhile, the excellent conductivity of the deposited PEDOT endows the composite with antistatic performance, accurate flexible strain and respiratory sensing behaviors, companying with encouraging UV resistance. The present work provides a feasible alternative for development of photothermal antibacterial, lightweight warm clothing and smart wearable textiles.

Scale and Impact of Sports Stadium Grow Lighting Systems In England

Recently, many sports stadiums have begun using high power lighting systems to help the grass grow on the playing surfaces. These lights supplement winter sunlight, which is sometimes insufficient due to the low elevation of the sun and shading from the surrounding walls. In many stadiums, grow lights are operated at night, and the waste light emissions from these stadiums are extraordinary in comparison to most other areas in the cities in which they are located. Here we present space-based observations of the radiance of fourteen stadiums located in towns and cities of varying sizes and in varying geographical locations across England which each have a Premier League football stadium. We show that stadiums have dramatically brightened (typically by factors of 2-5) in recent years compared to the situation in 2012. We also show that stadiums are often responsible for an important fraction of the total light emission of the cities they are in (often 10% or more, and in one case up to 30%). Because the light emissions from many English towns have been reducing in recent years, the overall fraction of light due to the stadiums is increasing. In some cases, total city emissions have actually increased due to the stadiums, undermining the environmental impact of reductions in radiance in the rest of the community. We believe that stadium grow lights are an excellent target for sustainable lighting initiatives, both because of their considerable environmental impact (especially when located near sensitive areas) and the possibility of high profile and successful waste light mitigation projects.

Photocatalytic removal of toxic dyes, liquorice and tetracycline wastewaters by a mesoporous photocatalyst under irradiation of different lamps and sunlight

Simple recyclable K5CoW12O40/TiO2 was synthesized and used to remove methyl orange, rhodamine B, direct red 16 and crystal violet toxic organic dyes, liquorice industrial wastewater and tetracycline (TC) as an antibiotic. Photoactivity of the catalyst was checked out under irradiation of various lamps (such as 18 W fluorescent, 300 W Xenon, LED and IR lamps). The best efficiency was obtained by fluorescent lamp at catalyst loading of 3 g/L, initial pH of 5, initial dye concentration of 5 ppm, complete degradation was achieved after 30 min contact time. Mechanistic investigation showed that·O2 radicals and h+ are majorly responsible for photodegradation in this process. Electrochemical investigation, Nyquist, Bode, Mott-Schottky, Tauc plots and photoluminescence proved that using this photocatalyst delay the electron-hole recombination, increase the lifetime of excited electron, extend light absorption to visible region and improve the light absorption capacity. This photocatalyst work well under winter sunlight. Also 97% and 84% dye removal was obtained for liquorice with 300 and 1000 COD at optimal condition. This catalyst showed similar activity for TC wastewater. Photocatalyst was characterized by FE-SEM, EDX, AFM, FT-IR, XRD, PL, DRS, EIS, BJH and BET.

МОДЕЛИРОВАНИЕ АРХИТЕКТУРНЫХ РЕШЕНИЙ ПАТИО И ИХ ВЛИЯНИЕ НА ТЕПЛОВОЙ КОМФОРТ ГОРОДСКОГО ЖИЛЬЯ В ПОЛУСУХОМ КЛИМАТЕ АЛЖИРА

The article aims to substantiate the role of the patio and its effect on thermal comfort in urban housing, especially in the semi-arid climatic zones of Algeria. In semi-dry cities, the aim is always to avoid direct sunlight and to seek shade and freshness in the summer season. Indeed, the patio is one of the bioclimatic architectural devices that responds to the field of indoor thermal environments and contributes to the creation of comfortable atmosphere. In this study, authors tried to assess the impact of patio geometry on thermal comfort inside housing in the semi-arid climate of Oum El Bouaghi. The study is based on the method of mathematical modeling implemented in the program ECOTECT. It evaluates the impact of the proportional coefficient H/L (height/width) on the value of PMV (Predicted Mean Vote), and PPD (Predicted Percentage of Dissatisfied). The results of this study show that the patio plays an important role in thermal comfort in urban housing. The patio significantly improves the PMV value and reduces the PPD value, increasing sunlight in winter and providing passive space cooling in summer. However, for optimal thermal comfort, the proportional H/L value must be greater than 2.5.

Bacterial Movement in Subsurface Soil during Winter Irrigation of Reclaimed Wastewater

Processes to remove and inactivate Escherichia coli from wastewater effluents and drainage are complex and interrelated. The objective of this study was to determine if irrigation of undisinfected wastewater effluents in the winter moves bacteria to surface water through subsurface drainage, posing a public health risk. The central Ohio study site, an open meadow constructed in the 1970s, is irrigated with lagoon effluents each summer. The irrigated area has subsurface drainage that collects for discharge in one spot. Undisinfected wastewater from a stabilization pond was irrigated for the first time in the winter of 2013/2014. E. coli was measured in the subsurface discharge during the irrigated winter season and compared to the non-irrigated previous winter season. Soil temperature and moisture were also monitored. E. coli moved to subsurface drains when the water table was above the drain. E. coli also moved to subsurface drains when the shallow soil temperature dropped to near freezing. With less winter sunlight and minimal evapotranspiration, the soil stayed moist near field capacity. Temperature appears to be the most important factor in limiting natural inactivation in subsurface soil and allowing the movement of E. coli in undisinfected wastewater effluents to the subsurface drainage systems. The results show that winter reuse of undisinfected wastewater does pose a public health risk to surface water through subsurface drainage. Therefore, disinfection of wastewater effluents used for irrigation is strongly recommended.

Outdoor environmental investigation of old communities during summer in hot summer and cold winter regions

The outdoor physical environments of many old communities are unable to meet modern living requirements and require improvement urgently. This is especially true for communities in regions with extremely hot summers and cold winters, which may cause additional difficulties. This study used measurements and questionnaire data to investigate outdoor environment (the thermal, sound, light environments and air quality) and resident sensations in four such communities. Results revealed some key factors affecting outdoor environmental comfort, including summer shading, winter sunlight, air temperature, air quality, the sound environment and odour. The results also revealed that the main problems were noise, insufficient illumination and high air temperatures in summer, all of which had seriously affected comfort during outdoor activities. Specifically, noise values during the most unfavourable periods were between 57.4 and 80.6 dB(A), while average air temperatures were between 32.3°C and 35.8°C, and average illuminances were below 2.9 lx. As such, this paper proposes improvement measures such as sound barriers and greening. Further, we propose a method for prioritizing these factors for such improvements based on a combination of subjective and objective factors. This study provides data and technical references for the reconstruction of old communities in regions with hot summers and cold winters.

Influence of the polar light cycle on seasonal dynamics of an Antarctic lake microbial community

BackgroundCold environments dominate the Earth’s biosphere and microbial activity drives ecosystem processes thereby contributing greatly to global biogeochemical cycles. Polar environments differ to all other cold environments by experiencing 24-h sunlight in summer and no sunlight in winter. The Vestfold Hills in East Antarctica contains hundreds of lakes that have evolved from a marine origin only 3000–7000 years ago. Ace Lake is a meromictic (stratified) lake from this region that has been intensively studied since the 1970s. Here, a total of 120 metagenomes representing a seasonal cycle and four summers spanning a 10-year period were analyzed to determine the effects of the polar light cycle on microbial-driven nutrient cycles.ResultsThe lake system is characterized by complex sulfur and hydrogen cycling, especially in the anoxic layers, with multiple mechanisms for the breakdown of biopolymers present throughout the water column. The two most abundant taxa are phototrophs (green sulfur bacteria and cyanobacteria) that are highly influenced by the seasonal availability of sunlight. The extent of the Chlorobium biomass thriving at the interface in summer was captured in underwater video footage. The Chlorobium abundance dropped from up to 83% in summer to 6% in winter and 1% in spring, before rebounding to high levels. Predicted Chlorobium viruses and cyanophage were also abundant, but their levels did not negatively correlate with their hosts.ConclusionOver-wintering expeditions in Antarctica are logistically challenging, meaning insight into winter processes has been inferred from limited data. Here, we found that in contrast to chemolithoautotrophic carbon fixation potential of Southern Ocean Thaumarchaeota, this marine-derived lake evolved a reliance on photosynthesis. While viruses associated with phototrophs also have high seasonal abundance, the negative impact of viral infection on host growth appeared to be limited. The microbial community as a whole appears to have developed a capacity to generate biomass and remineralize nutrients, sufficient to sustain itself between two rounds of sunlight-driven summer-activity. In addition, this unique metagenome dataset provides considerable opportunity for future interrogation of eukaryotes and their viruses, abundant uncharacterized taxa (i.e. dark matter), and for testing hypotheses about endemic species in polar aquatic ecosystems.3rEAa4a8EPvdQSJ1TDqSyzVideo

EFFECT OF DIRECT SUNLIGHT AND UV-RAYS ON DEGRADATION OF BUPIRIMATE, PENCONAZOLE AND PROFENOFOS

The exposure to sunlight, UV-rays led to the degradation of the pesticides formulations (Namrod 25% EC) bupirimate, (Agrozole 10% EC) penconazole and (Actacron 72% EC) profenofos. Their residues were determined by high performance liquid chromatography (HPLC). The results showed that exposure to direct sunlight in (Winter at the morning) was more effective in degradation of the tested pesticides than exposure to direct sunlight in (Winter at the evening) for 4 hours. The percentage residue of bupirimate, penconazole and profenofos were 18.24, 48.52 and 19.26 % in winter at the morning, respectively. Therefore, bupirimate was the highest affected by this treatment. Also, the data showed that exposure to direct sunlight in (Summer at the evening) was more degraded than exposure to direct sunlight in (Summer at the morning) for 4 hours. The percentage residue of bupirimate, penconazole and profenofos were 11.14, 15.45 and 7.72 % after 4 hours in (Summer at the evening), respectively. Therefore profenofos was more degraded than other pesticides. In general the degradation of the tested pesticides in summer was higher than winter. Withal, the data demonstrated that the exposure to UV-ray at distance 22.5 cm was more effective in degradation of the three tested pesticides than exposure to UV-ray at distance 45 cm for 4 hours where, the percentage residue of bupirimate, penconazole and profenofos were 17.08, 39.56 and 15.00 % after 4 hours of exposure to UV-ray at distance 22.5 cm respectively, and therefore profenofos was the highest degraded in the three pesticide in the same period of exposure to UV-ray.

On a Lovefeast of Yesterdays, and: Seven Cantos on Silence as Via Negativa, and: Ode to My Namesake on the Other Side of the Universe

On a Lovefeast of Yesterdays, and: Seven Cantos on Silence as Via Negativa, and: Ode to My Namesake on the Other Side of the Universe Karen An-Hwei Lee (bio) On a Lovefeast of Yesterdays No word for the scent, we say, on a road of dipson our way to the sweetest spot in the foothillswhere we ate spice cookies, airy, crisp as autumnwith cakes baked right next to the blacksmiths,a hedge-maze by a church with an acre cemetery—none of it tasted bitter, rather, sweet without smokeswirling in our lungs, without honey-laced beeswax,nor the rolled cigars lying asleep in their boxesfor shipment, nor barrels of molasses, nor hickory,not tar or nougat or malt whiskey, not gingersnapsor chocolate chess pie or black sugar. We relisha lovefeast of yesterdays, pin up elusive syllablesof fragrance wafting through avenues in searchof loaves or leaves cured in bakeshops, the housesof shivering air elusive as an aroma of nostalgia—mulching a ferny floor in the hills, a festive crushof tobacco drying with a brisk sweetness of angelsobserving us with eyes on a world where the name of a thing is not the thing itself. [End Page 140] Seven Cantos on Silence as Via Negativa canto 1.(Neither is the word silence equivalent to the loveliest of lovely days beginning with love and lengthening with the light where an open parenthesis never closes— canto 2.Neither is it an invisible flock of small en dashes flying in hyphens of horizontal light to a skylinewhere little nothings brush the air with em dashes as pauses or broken spaces and caesuras where sound vanishesin a pear-shaped curve of the world, this eardrum pushing against the reverberation of cold winter light on the floor— pupils dilating in the unfastened ink of the dark. canto 3.(The fog in a green church of wind on the sea cliff— canto 4.In a grove, feral lorikeets in a red-gum eucalyptusfall silent, awed by a solar eclipse in winter—sunlight dims in a kelp forestwhere swimmers drowned, their legs tangled by ribbonsof silence, undersea deaths by apnea— canto 5.Phenomena in antithesis to silence— white noise of engines spinning in turbines, a dial tone on a rotary telephone the color of oranges,thunder rolling over foothills, signposts telling the miles ahead, [End Page 141] and a memory of sweet-tongued heat pooling in a jar of early summer marmalade,pink lemons whose rose-quartz flesh shouted with honey— maddening honey of sugar and roses, a mineralmatrix of molten sweetness. canto 6. Silence is a dashed grammar of punctuated roses,brackets blossoming without desire for closure, or fragrant elision and contraction, ellipses in the motion of an eye petaling across quartos folded one inside the other as mutual offerings.For a spring season, I wait on God to speak a word, i.e. blooming, blooming, blooming— wherein I also learn how God repliesin the manner of an open parenthesis which is no sound at all. (My presencewill go with you, and I will give you rest— canto 7.The quietest room in the world is not silence. The word silence is not silence.Such irony—cantos on silence verb and verb so much sound.) Ode to My Namesake on the Other Side of the Universe A woman with my name, Karen,lives on the other side of the universe—probing non-small cell lung cancer, [End Page 142] microscopic radial scars, magneticresonance imaging, liquid diagnosticplatforms for biopsies, designing new cures in her field of cancermedicine. As her quiet counterpart,a poet on this side of the universe, I wonder if angels hover by her faceat night like mine while messengerssoar under low evening clouds, laughing in a swirl of lucid dreaming, updraftssoaked in the intoxicating fragranceof mad honey flowing out of portals of lost Karens—extinction of loves,the vestiges of sea-faring pilgrims,polar ice caps melting by degrees, the delirium of time itself flungin starry vectors of the inevitableshot through to the survival of eponymous...

Sunlight‐Triggerable Transient Energy Harvester and Sensors Based on Triboelectric Nanogenerator Using Acid‐Sensitive Poly(phthalaldehyde)

AbstractTransient electronics that disintegrate via material dissolution or depolymerization under certain stimuli have great potential in biomedical and military applications. The triboelectric nanogenerator (TENG), an emerging mechanical energy harvesting technology with great flexibility in material choices, is promising in offering transient power sources. Previously reported transient energy harvesters using biodegradable polymers require solution‐based degradation and have limited applications in non‐biological scenarios. A short time span, sunlight‐triggered degradable TENG is developed. The main substrate includes an acid‐sensitive poly(phthalaldehyde) (PPHA), a photoacid generator (PAG), and a photosensitizer (PS). Through photo‐induced electron transfer, the ultraviolet radiation absorbed by the PS is transferred to the PAG to generate photoacids that trigger the depolymerization of PPHA. Transient TENG‐based mechanical energy harvesters and touch/acoustic sensors are successfully demonstrated by embedding silver nanowires onto the PPHA‐based films. The fabricated devices degrade rapidly under winter sunlight. The degradation rate can be further tuned via changing the ratio of photosensitive agents. This work not only broadens the applicability of TENG as transient power sources and sensors, but also extends the use of transient functional polymers toward advanced energy and sensing applications.

Time-series analysis of geographically specific monthly number of newly registered cases of active tuberculosis in Japan.

BackgroundUnderstanding seasonality of tuberculosis (TB) epidemics may lead to identify potentially modifiable risk factors. Studies conducted outside Japan have found seasonal variation among reported TB cases, with peaks in spring and summer and low prevalence in fall and winter. One hypothesis regarding spring or summer peaks in TB epidemics is that TB transmission likely increases in winter because of indoor crowding and poor ventilation, with development of primary TB among socially vulnerable people in spring and summer. Another plausible explanation is that vitamin D deficiency in winter depresses immunity, increasing the TB reactivation risk in these seasons. Previous studies suggest latitude-dependent factors, including reduced winter sunlight and its effect on vitamin D levels. Here, we investigated mechanisms of seasonality in TB epidemics in Japan, according to the effects of crowding and latitude.MethodsWe used time-series analysis consisting of spectral analysis and least-squares method, to analyse geographically specific monthly number of newly registered cases of all forms of active TB in all 47 prefectures of Japan during 1998–2015.ResultsIn all power spectral densities for the 47 prefectures, spectral lines were observed at frequency positions corresponding to a 1-year cycle. The degree of this seasonality was associated with population density. We did not detect greater amplitude of seasonality at higher latitudes, suggesting that latitude-dependent factors, including reduced winter sunlight and its potential effect on vitamin D levels, do not contribute significantly to seasonality in Japan.Discussion and conclusionIn districts with high population density, measures are needed to address two specific types of active infection risk in adolescents and middle-aged adults: (i) public transport use, and (ii) irregular employment with no periodic medical examinations. To control active TB epidemics, investigating periodic structures in the temporal patterns of active TB in each district and each age group is important.

Author response: Neonatal vitamin D status and risk of multiple sclerosis: A population-based case-control study.

In response to our article,1 Dr. Zarghami suggests that clinical trials are necessary to compare the efficacy and cost–benefit of vitamin D supplementation vs sun exposure in pregnancy. Such trials are not feasible because of the relatively low frequency of multiple sclerosis (MS) and the long interval between any intervention in pregnancy and the observation of its potential effect on MS risk in offspring. We agree, nevertheless, that judicious sun exposure provides an alternative approach for the correction of vitamin D deficiency in regions with levels of ultraviolet B radiation high enough to support year-round vitamin D production. This is not the case in countries like Denmark, where winter sunlight cannot produce sufficient vitamin D levels.2

Light absorption and the photoformation of hydroxyl radical and singlet oxygen in fog waters

The atmospheric aqueous-phase is a rich medium for chemical transformations of organic compounds, in part via photooxidants generated within the drops. Here we measure light absorption, photoformation rates and steady-state concentrations of two photooxidants – hydroxyl radical (•OH) and singlet molecular oxygen (1O2*) – in 8 illuminated fog waters from Davis, California and Baton Rouge, Louisiana. Mass absorption coefficients for dissolved organic compounds (MACDOC) in the samples are large, with typical values of 10,000–15,000 cm2 g-C−1 at 300 nm, and absorption extends to wavelengths as long as 450–600 nm. While nitrite and nitrate together account for an average of only 1% of light absorption, they account for an average of 70% of •OH photoproduction. Mean •OH photoproduction rates in fogs at the two locations are very similar, with an overall mean of 1.2 (±0.7) μM h−1 under Davis winter sunlight. The mean (±1σ) lifetime of •OH is 1.6 (±0.6) μs, likely controlled by dissolved organic compounds. Including calculated gas-to-drop partitioning of •OH, the average aqueous concentration of •OH is approximately 2 × 10−15 M (midday during Davis winter), with aqueous reactions providing approximately one-third of the hydroxyl radical source. At this concentration, calculated lifetimes of aqueous organics are on the order of 10 h for compounds with •OH rate constants of 1 × 1010 M−1 s−1 or higher (e.g., substituted phenols such as syringol (6.4 h) and guaiacol (8.4 h)), and on the order of 100 h for compounds with rate constants near 1 × 109 M−1 s−1 (e.g., isoprene oxidation products such as glyoxal (152 h), glyoxylic acid (58 h), and pyruvic acid (239 h)). Steady-state concentrations of 1O2* are approximately 100 times higher than those of •OH, in the range of (0.1–3.0) × 10−13 M. Since 1O2* is a more selective oxidant than •OH, it will only react appreciably with electron-rich species such as dimethyl furan (lifetime of 2.0 h) and substituted polycyclic aromatic hydrocarbons (e.g., 9,10-dimethylbenz[a]anthracene with a lifetime of 0.7 h). Comparing our current Davis samples with Davis fogs collected in the late 1990s shows a decrease in dissolved organic carbon content, similar mass absorption coefficients, lower •OH concentrations, but very similar 1O2* concentrations.

Holocene storminess inferred from sediments of two lakes on Adak Island, Alaska

The abundance of sedimentary organic material from two lakes was used to infer past Holocene storminess on Adak Island where frequent storms generate abundant rainfall and extensive cloud cover. Andrew and Heart Lakes are located 10km apart; their contrasting physical characteristics cause the sedimentary organic matter to respond differently to storms. Their records were synchronized using correlated tephra beds. Sedimentation rates increased between 4.0 and 3.5ka in both lakes. Over the instrumental period, Andrew Lake biogenic-silica content (BSi) is most strongly correlated with winter sunlight availability, which influences photosynthetic production, and river input, which influences the dilution of BSi by mineral matter. Heart Lake BSi is likely affected by wind-driven remobilization of sediment, as suggested by correlations among BSi, the North Pacific Index, and winter storminess. The results indicate relatively stormy conditions from 9.6 to 4.0ka, followed by drying between 4.0 and 2.7ka, with the driest conditions from 2.7 to 1.5ka. The stormiest period was between AD 500 and 1200, then drying from 1150 to 1500 and more variable until 1850. This record of Holocene storminess fills a major gap at the center of action for North Pacific wintertime climate.