Winter Solstice Research Articles

Performance Evaluation of Flexible Photovoltaic Panels for Energy Supply in Post-Disaster Emergency Shelters

In the event of disasters, the provision of energy encounters significant challenges. Flexible photovoltaic (FlexPV) is an ideal choice for emergency shelters to supply the daily activities for displaced populations. S(P)EEDKITS is a project to develop rapid deployable emergency shelters as seeds of self-recovery. Based on the project, this study is to assess the feasibility of FlexPV on the roof of emergency shelters. Various measurements have been conducted on a multipurpose tent to investigate the reliability of the flexible solar cells, thermal performance, acoustic performance, and power generation in the winter solstice. From the results, the Electroluminescence tests show that serious microcracks occur on the FlexPV cells after a long-term application, which is hidden danger for power output. I-V tests show the degradation of PCE is within 2.8% after one year usage Moreover, the energy yield during the winter solstice is sufficient to fulfill the minimum power requirement essential for the effective operation of the emergency shelter in Milan. Additionally, the integration of FlexPV panels causes an average 8.6 °C temperature increase, showing a negative influence on the power output of FlexPV. Finally, the integration leads to a 6.7% increase of the indoor noise. So, the FlexPV panels are more suitable to be applied for a short period of time after disaster to solve the energy crisis of disaster victims.

三发市华人冬至节传统习俗概况

<p>The title of this study is “Overview of Traditional Customs of Chinese Winter Solstice Festival in Sambas City”. The winter solstice is a very important solar term in the lunar calendar, it is the 22<sup>nd</sup> of the 24 solar terms. The winter solstice is also a traditional festival. The Winter Solstice is generally celebrated on December 21<sup>st</sup> or 22<sup>nd</sup> of the lunar calendar. The winter solstice was once called “eating glunious rice balls” by Chinese Indonesians. The purpose of the research is to understand the customs and significance of the Sambas city Winter Solstice Festival and the differences between Sambas and Chinese Winter Solstice Festivals. The author chooses Sambas Chinese as the research object. The data collection method used in this article is interviews. It can be seen from the interview results that the Sambas Chinese still celebrate the Winter Solstice Festival, but many people do not understand the meaning, significance and customs of the Winter Solstice Festival. With the development of the times, many traditional customs have gradually changed, and some customs have even slowy disappeared.</p>

Multi-scale correlation analysis between geometric parameters and solar radiation in high density urban environment——Case study in Nanjing

This study explores the impact of multi-scale urban morphology on solar radiation in high-density environments, focusing on Nanjing as a case study. Using Grasshopper, the research decomposed urban models into four scales—district, block group, block, and plot—and analyzed eight morphological indicators, including site coverage (SC), floor area ratio (FAR), and block surface ratio (BSR). Solar radiation was simulated for the entire year, the summer solstice, and the winter solstice. Key findings reveal that different scales exhibit varying influences on solar radiation. At the district scale, BSR shows the highest correlation with annual solar radiation (R2 = 0.96), while at the neighborhood cluster scale, the minimum distance between buildings (DBmin) is most correlated (R2 = 0.7). At the block scale, BSR significantly correlates with summer solar radiation (R2 = 0.55). At the plot scale, no single indicator strongly correlates with solar radiation, but a combination of indicators is more relevant. These findings enable rapid solar performance assessments in urban design, promoting efficient solar energy use.

Theoretical analysis of upward-heating multiple-effect diffusion solar still with parabolic dish concentrator

Upward-heating multiple-effect diffusion solar still (UHMEDS) coupled with a parabolic dish concentrator (PDC) was proposed and analyzed theoretically. UHMEDS has cover glass, several partitions and preheating cover, and wicks are placed on the upper surfaces of partitions and preheating cover. Saline water preheated on the preheating cover flows down the partitions by gravitational force. The lowermost partition of UHMEDS was heated by solar energy collected by PDC. The basic behavior of UHMEDS at Fukuoka, Japan was analyzed theoretically by modeling heat and mass transfer in the still. The theoretical results show that PDC can collect the sunrays to the lowermost partition of UHMEDS effectively, and the overall daily productivity of the still was predicted to be about 18.5, 24.5 and 10.4 kg/m2day on spring equinox, summer and winter solstice days, respectively, which values are almost equivalent to those of other types of multiple-effect diffusion solar still.

Seasonal and Interhemispheric Variations of the Afternoon Auroral Responses to the Interplanetary Magnetic Field By Polarity

AbstractThis work investigates seasonal and interhemispheric variations of the afternoon auroral responses to the interplanetary magnetic field (IMF) By effects. The auroral observations are adopted from the global ultraviolet imager instrument on board the Thermosphere Ionosphere Mesosphere Energetics and Dynamics (TIMED) satellite during 2002–2007. The results show that in both summer and winter solstices, the stronger afternoon auroral intensity is associated with negative IMF By (By < 0) in the northern hemisphere, and with By > 0 in the southern hemisphere. This suggests stronger contributions from the upward field‐aligned currents (FACs), which can be induced by the By‐associated north‐south oriented electric field and the By‐associated flow shear in the ionosphere. In addition, the strongest afternoon aurora occurs in summer in each hemisphere. In summer, the absolute difference between the auroral peak intensity under the two By polarities is greater and occurs earlier than in winter, which may be related to changes in FACs and conductivity from winter to summer. Differently, in equinoxes stronger auroral intensity favors By conditions associated with more frequent occurrence of southward IMF Bz, such as By < 0 and By > 0 conditions in March and in September, respectively. Therefore, in equinoxes the effects of the favorable By, which were seen in solstices, are masked. We suggest that these are caused by the Russell‐McPherron effect, which leads to more southward Bz conditions, resulting in more energy deposited and subsequent stronger aurora in polar ionosphere. These results contribute to our deeper understanding of the asymmetrical phenomena in the Earth's magnetosphere‐ionosphere induced by IMF By.

The possibilities of GIS technologies for assessing and monitoring the climatic conditions of the Makazhoy Fepression (Chechen Republic, Russia)

Modeling based on a digital relief model of the spatiotemporal change in the amount of total solar radiation and the assessment of the contribution of locations to the distribution of meteorological elements.DEM analysis was conducted in a GIS environment to assess the spatial and temporal distribution of total solar radiation, and statistical analysis of retrospective climatic and actual (2023) meteorological data was conducted.Based on a digital model of the relief of average spatial resolution in a GIS environment, changes in the spatial and temporal magnitude of solar radiation were estimated. A prospective analysis of climatic conditions made it possible to assess the general features of the climate of the Makazhoy basin Field observations made it possible to characterize modern climatic conditions, as well as to calculate gradients.Depending on the locations, it was determined that the amount of total solar radiation in the Makazhoy basin varies by almost 3 times. Within the same altitude intervals, the difference between the slopes of the southern and northern exposures reaches up to 50 %. The smallest differences in the amount of radiation were observed on the days of the summer solstice, and the largest on the days of the winter solstice. The average annual air temperature in the altitude range of 1960–2264 m in 2023 varied from 8.6 to 5.8°, and the amount of precipitation – from 481 to 525 mm, respectively. The intra‐annual course of meteorological parameters (air temperature and leaf surface, precipitation and relative humidity) within the meteorological transect has been revealed. The data obtained make it possible to proceed to the formation of a GIS system for monitoring the climatic conditions of the carbon landfill of the Kadyrov Chechen State University.

Determination of Rhythmicity and Gestational Stage-Related Distribution of Blood Plasma Melatonin Concentrations in Donkey Mares.

The aim of this study is to obtain a more complete picture of blood plasma melatonin concentrations in the donkey mares. To this purpose, sampling and statistical processing were carried out in such a way that allowed the researchers to establish the annual and daily rhythms. Based on human observations, according to the hypothesis of the authors, the blood plasma melatonin concentration of pregnant individuals rises during the late gestational period, before parturition. To confirm this, the melatonin concentrations of pregnant and non-pregnant jennies were monitored and compared. In regard to the circannual rhythm, the significantly lowest midnight melatonin value (27.67 pg mL-1) was typical for the summer solstice. Under consideration of circadian changes, a significantly strongest melatonin production (45.16 pg mL-1) was observed on the night of the winter solstice (p < 0.001). Considering gestational age, the blood plasma melatonin concentration (around 38 pg mL-1) does not change as gestation progresses (p = 0.136). The results obtained in this studied population of the domestic ass usefully expand the little knowledge previously gathered about the development of the blood plasma melatonin concentrations of this species.

The effectiveness and safety of acupoint herbal patching for allergic rhinitis: protocol for a systematic review and meta-analysis

BackgroundAllergic rhinitis (AR) is a common inflammatory disease of the nasal mucosa that is characterized by symptoms such as sneezing, nasal congestion, nasal itching, and rhinorrhoea. In recent years, acupoint herbal patching (AHP) therapy has gained a growing interest as a potential management option for AR. This systematic review and meta-analysis will evaluate the clinical research evidence on the effectiveness and safety of AHP as a treatment option for AR outside of the Sanfu or Sanjiu days (summer or winter solstice). The results of this review will provide up-to-date evidence-based guidance for healthcare providers and individuals seeking alternative treatments for AR.MethodsA comprehensive search of electronic databases (PubMed, Cochrane Central Register of Controlled Trials (CENTRAL), EMBASE, China National Knowledge Infrastructure (CNKI), CQVIP, Sino-Med, and Wanfang Databases) will be conducted from their inception to June 2023. The inclusion criteria will be limited to randomized controlled trials that evaluate the effectiveness or efficacy of non-Sanfu or non-Sanjiu AHP for AR. The primary outcome measure will be the total nasal symptom score. The methodological quality of included studies will be assessed using the Revised Cochrane risk-of-bias tool for randomized trials (RoB 2), and meta-analyses will be performed using RevMan (V.5.3) statistical software. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach will be used to determine the certainty of evidence.DiscussionThis systematic review and meta-analysis will provide valuable insights into the effectiveness and safety of non-Sanfu or non-Sanjiu AHP as a treatment option for AR. The study aims to produce a high-quality review by adhering to PRISMA-P guidelines and using clinical guideline recommended outcome measures. The results of this review may offer additional treatment options for AR patients who seek complementary and alternative therapies, and hold significant implications for future research in this field. Overall, this study has the potential to inform clinical practice and improve patient outcomes.Systematic review registrationPROSPERO CRD42022181322.

Projected changes in ultraviolet index and UV doses over the twenty-first century: impacts of ozone and aerosols from CMIP6.

This study evaluated the health-related weighted ultraviolet radiation (UVR) due to the total ozone content (TOC) and the aerosol optical depth (AOD) changes. Clear-sky Ultraviolet Index (UVI), daily doses, and exposure times for erythema induction (Dery and Tery) and vitamin D synthesis (DvitD and TvitD) were computed by a radiative transfer estimator. TOC and AOD data were provided by six Earth System Models (ESMs) from the Coupled Model Intercomparison Project Phase 6 (CMIP6). For projections, we consider four Shared Socioeconomic Pathways scenarios-SSPs (SSP1-2.6, SSP2-4.5, SSP3-7.0, and SSP5-8.5)-and two time-slices (near: 2041-2060 and far future: 2081-2100). UVR projections showed pronounced changes for the summer hemispheres in the far future. TOC increases in mid- and high latitudes of the Southern Hemisphere caused decreases in UVR at the summer solstice. However, projections did not indicate sun-safe exposure conditions in South America, Australia, and Southern Africa. On the contrary, exposure around solar noon from 10 to 20min will still be sufficient to induce erythema in skin type III individuals throughout this century. In southern Argentina and Chile, the UVR insufficiency for vitamin D synthesis at solar noon in skin type III remains the same during this century at the winter solstice. In the Northern Hemisphere, UVI and Dery at the summer solstice should remain high (UVI ≥ 8; Dery ~ 7.0kJm-2) in highly populated locations. Above 45 °N, UVR levels cannot be enough to synthesize vitamin D in skin type III during the boreal winter. Our results show that climate change will affect human health through excess or lack of solar UVR availability.

The Feature Analysis and Modeling of Upper Atmospheric Midnight Density Maximum

The features of upper atmospheric midnight density maximum (MDM) around low geographic latitudes are studied based on neutral mass densities data at altitudes 360–480 km, derived from the accelerometer measurements aboard on the three polar orbiting satellites CHAMP (CHAllenging Minisatellite Payload), GRACE-A (Gravity Recovery and Climate Experiment-A), and SWARM-C (The Earth's Magnetic Field and Environment Explorers-C). The MDM appears during the local times from 23:00 to 02:00 LT (Local Time), whose peak locates at the low latitudes within 15∘ and two valleys locate at the middle latitudes between 35∘ and 45∘ on both hemispheres separately. The structure of MDM drifts toward the southern hemisphere overall. The MDM's amplitude decreases with increases in altitude and solar radiation level. The seasonal effect weakens the MDM's amplitudes around the summer and winter solstices, while the amplitudes around the spring and autumn equinoxes are extremely significant due to the slight seasonal difference between both hemispheres. Three atmospheric density models DTM2000 (Drag Temperature Model 2000), NRLMSISE00 (US Naval Research Laboratory Mass Spectrometer and Incoherent Scatter Radar Extended atmosphere model), and JB2008 (Jacchia-Bowman 2008 model) are used to simulate the MDM along these three satellites' orbits, and compared with the observations. It is found that the JB2008 model is failed to describe the MDM, and the other two models underestimate the MDM's amplitudes at altitudes 360 km and 480 km: the simulated amplitudes by the DTM2000 model are 46% and 53% of the observed amplitudes, respectively, and only 33% and 26% for the NRLMSISE00 model. These three models are also failed to depict the MDM's variation with altitude, solar radiation level, and seasonal effects. In order to correct the model prediction, a 6th-order Legendre polynomial of geographic latitude, coupled with arguments of local time and altitude, is designed to fit the MDM signals from the three satellites' observations. In terms of amplitude and phase of the MDM, the fitting results agree with the observations very well, and the correlation coefficient is 0.923. It indicates that this empirical polynomial could be helpful to the density model correction and high accuracy prediction of spacecrafts in low Earth orbits.

The Cultural, Sexist Sanitization of Santa Claus

A cross-cultural historical examination of Santa Claus reflects that women have contributed substantially to the legend of Santa Claus, but their contributions are downplayed, demeaned, or reframed to fit a sexist view of women’s roles. Santa Claus type figures have emerged around the world as part of celebrations of the winter solstice, but strategically removed from their original cultural context to be portrayed to be part of a Christian holiday, when in fact they are not. In most reviews of the winter holidays around the world, there is almost no mention of the vital role that women play in their creation and sustainability. In a diversified world, it is time to change the narrative of this altruistic figure so that he can become more inclusive for all.

Morphology of equatorial F-region irregularities over the Indian longitude sector using GPS-derived ROTI observations

The occurrence characteristics of Equatorial F-region Irregularities (EFIs) along the Indian longitude sector are investigated using GPS-derived ROTI observations from 2010 to 2023, under both quiet and disturbed geomagnetic conditions. The analysis of the results emphasizes a strong dependence of EFIs occurrence on solar cycle variation. Additionally, the EFIs are more intense at the EIA regions under maximum solar activity periods attributed to the high ambient electron density in the F-layer. The occurrence of EFIs is found to be severe and frequently observed in equinox seasons in contrast to solstice seasons. Also, the occurrence of EFIs exhibits equinoctial asymmetry with more intense EFIs in the spring equinox than autumn equinox during the peak and declining periods of the solar cycle. Conversely, severe EFIs are observed during autumn equinox than spring equinox in the ascending phase of the solar cycle. The seasonal occurrence probability of EFIs is highest in the equinox seasons, following the winter solstice, and summer solstice in high solar activity conditions. Investigations of EFIs during two prominent geomagnetic storm events (17 March 2015 and 08 September 2017) during the study period show that the storm-induced Prompt Penetration Electric Fields (PPEFs) modulated the regular intensity of dusk time Pre-Reversal Enhancement (PRE), resulting in poleward expansion of ionospheric irregularities up to mid-latitude regions with spatial time lag. However, storm-induced westward electric fields and oscillating IMF Bz created Counter Electrojet (CEJ) like conditions, suppressing the dusk time ionospheric irregularities over dip equatorial and low-latitude regions on 17 March 2013. This study provides a comprehensive understanding of how ionospheric irregularities manifest under varying conditions, thereby supporting further research on substantiating the spatiotemporal EFIs characteristics and their predictions over the region.

Optimal design of multilayer optical thin film structure for smart energy saving applications using needle optimization approach

In this work, a novel design of a one dimensional photonic crystal (1D PC) is investigated. The 1DPC structure is composed of alternating layers of tantalum pentoxide (Ta2O5) and silicon dioxide (Sio2). The proposed 1D PC structure is designed to act as short wave pass (SWP) edge filter that selectively passes light of short wavelengths, while the infrared light is blocked. In this study, Essential Macleod software is used to create the optimal design with the computational support of the needle synthesis technique. By varying the incidence angle of the mean polarized light mode, we can determine the features of the optimal SWP edge filter design, which leads to an important application for this filter. It can shed light on the filter’s suitability as a smart energy saving window coating for hot climate regions. The study includes different hot regions in Saudi Arabia such as Mecca, Riyadh, Dammam, Arar and Alaqiq. They were used as case studies in this research. According to the study of the optimal design of SWP edge filter applied in Mecca, Riyadh, Dammam, Arar and Alaqiq provinces, the light transmittance in the visible region is more than 99% during the summer solstice and more than 96% during the winter solstice. The photonic band gab (PBG) is almost constant during the summer solstice without shifting or decreasing in size whereas in the winter solstice, the PBG shifts toward the short wavelengths and decreases in size by increasing the angle of incidence. This allows an amount of solar energy to enter in winter. Riyadh, Dammam, and Arar provinces experienced a significant increase in solar energy during the winter solstice, more than Mecca and Alaqiq provinces.

Study on saline-alkali water distillation system by reflection enhanced solar heating

A saline-alkali water distillation system by reflection enhanced solar heating is proposed to treat the saline-alkali soil washing water. In this system, the heat concentration collector employs heat collecting plate to receive solar radiation energy, and converges to small-area steam generating tube through efficiently heat transfer. Without expensive optical tracking equipment, the system also employs an external reflector to reflect the solar radiation to the surface of the heat concentration collector. Thereby the energy flow density is further increased, and the useful energy and vaporization intensity is promoted. The latent heat of the steam is reused by heat recovery to enhance the energy utilization efficiency. The optimal inclination angles of reflector in different seasons and system performance were theoretically calculated. In the spring equinox, summer solstice, autumn equinox, and winter solstice, the optimal inclination angles of the reflector were 30°, 45°, 30°, and 15°, respectively. The freshwater production, useful energy, and heat recovery efficiency of the system were investigated by experiments. The daily freshwater production of the system was 17.04 kg, and the maximum production rate was 3.44 kg/h. The reflector increased the useful energy and freshwater production of the system by 33.68% and 35%, respectively. With heat recovery, the initial temperature of the saline-alkali water was increased to 53.8 °C and the freshwater production was increased by 13.16%.

Seasonal variation of melatonin secretion across various segments of the gastrointestinal tract in rats

ObjectiveTo investigate whether melatonin (MT) secretion in different parts of the gastrointestinal tract (GIT) exhibits seasonal variations and its correlation with immune regulation. MethodsSixty Sprague-Dawley rats were divided into control and model groups, and the pineal gland was removed in the model group. Stomach, jejunum, ileum, and colon tissues were obtained during the spring equinox, summer solstice, beginning of autumn, autumn equinox, and winter solstice. The levels of MT, MT receptors (MR), arylalkylamine N-acetyltransferase (AANAT), hydroxyindole-O-methyltransferase (HIOMT), interleukin-2 (IL-2), and interleukin-10 (IL-10) in the GIT were measured using enzyme-linked immunosorbent assay. ResultsExcept for the stomach, the jejunum, ileum, and the colon showed seasonal tendencies in MT secretion. In the control group, MT secretion in the jejunum and ileum was the highest in the long summer, and colonic MT secretion was the highest in winter. In the model group, MT levels in the colon were highest in the summer. The seasonal rhythms of the MR, AANAT, HIOMT, IL-2, and IL-10 in the colon were roughly similar to those of MT, and changed accordingly after pinealectomy. ConclusionsGastrointestinal MT secretion is related to seasonal changes, and MT secretion in each intestinal segment is influenced by different seasons. The biological effects of MT in the gut are inextricably linked to the mediation of MR, and a hormone-receptor linkage exists between MT and MR. The effect of seasonal changes on the gastrointestinal immune system may be mediated through the regulation of seasonal secretion of MT.

Estimation of Pointing Errors of Large Radio Telescopes under Solar Radiation Based on Digital Twin

The pointing accuracy of large radio telescopes is affected by antenna structure errors, installation errors, servo errors, gravity, and varying environmental factors. Although an on-line pointing model had been developed in the past for several large radio telescopes to correct these effects, it is also valuable to explore new ways to correct these effects. Therefore, in order to estimate the dynamic pointing error of large radio telescopes under solar radiation, a new way based on digital twin (DT) is used in this paper. Digital models of the Wuqing 70-m radio telescope (WRT70) are created based on the DT operational framework. Finally, the reliability of the WRT70’s DT system is verified, and the dynamic pointing error of WRT70 (staying at the position of the elevation angle of 90° and the azimuth angle of 180°) on two sunny days in different seasons is estimated by the created DT system. The research results show that the pointing error of large radio telescopes under solar radiation fluctuates greatly and the seasonal differences are very striking. The maximum elevation pointing error of WRT70 under solar radiation around the winter solstice is over 40 arcsec, which is equal to 4/11 of the beam width for WRT70 operating at 8 GHz. In this paper, it is feasible to estimate the time-varying pointing errors of large radio telescopes at rest under solar radiation by constructing a DT system, but it is not effective to estimate the dynamic pointing errors of large radio telescopes in operation. It is expected to establish a dynamic pointing error model and calibrate the dynamic pointing errors of large radio telescopes in operation by DT technology in the future.

Performance analysis of a novel solar Linear Fresnel concentrator system based on spectral beam splitting

Photothermal and photovoltaic are the most common and commercialized ways of utilizing solar energy. However, they cannot use solar energy efficiently. SBS (spectral beam splitting) technology is an efficient solar energy utilization technology that can realize the full spectrum utilization of solar energy. The current work involved: (1) Proposing a SBS-LFCs (linear Fresnel concentrator system) based on spectral beam splitting. In this system, the SBS photovoltaic panel replaces the conventional linear Fresnel concentrator lens, which can realize photovoltaic and photothermal utilization at the same time; (2) Developing a spectral splitting thin films configuration using the Needle method whose transmittance is higher than 90% against 380 nm-1100 nm band range; (3) Designing the SBS photovoltaic panel structure. The cover glass surface is covered with a SBS thin film. The SBS photovoltaic panel replaces the concentrator lens of LFCs; (4) Taking four typical days as examples, the annual power generation of a SBS linear Fresnel focusing system was predicted. The outcome indicates that the total conversion efficiency of solar thermal power in the system is 23.8%, 23.5%, 23.5%, and 23.6% on the spring equinox, summer solstice, autumn equinox, and winter solstice, respectively. Compared to conventional monocrystalline silicon cells, the photoelectric conversion efficiency has been improved by 14.6%, 12.8%, 12.5%, and 14.1%, respectively.

ECONOMIC FEASIBILITY OF ON-GRID PHOTOVOLTAIC SYSTEMS IN A SINGLE-FAMILY HOUSE IN RIO DE JANEIRO CITY

Brazil is a tropical country with favorable conditions for the generation and utilization of solar energy. This energy source becomes even more attractive when considering the dry periods that impact hydroelectric power generation in the country, resulting in an increase in energy costs reflected monthly in consumers' bills through tariff flags. In order to enhance residential architectural designs and promote energy efficiency, a feasibility study of photovoltaic systems was conducted, considering key economic indicators and the current tariff flags. To accomplish this, research was conducted in collaboration with Mounting Companies for a case study located in the city of Rio de Janeiro, adopting technical assumptions commonly used for residential photovoltaic system sizing. For the graphical sizing of the case study, factors such as the environment and summer and winter solstices were taken into account, and a shadow study was conducted to assess the potential loss of power generation by the photovoltaic system throughout the year. The shadow study revealed that, during both solstices, the optimal time for power generation by photovoltaic systems is between 9 a.m. and 6 p.m. Essentially, the calculated values of NPV (Net Present Value) and IRR (Internal Rate of Return) indicate that the project is economically viable and particularly advantageous during the yellow and red tariff flags, situations in which energy costs tend to be higher for consumers.

Seasonality in regional brain glucose metabolism.

Daylength and the rates of changes in daylength have been associated with seasonal fluctuations in psychiatric symptoms and in cognition and mood in healthy adults. However, variations in human brain glucose metabolism in concordance with seasonal changes remain under explored. In this cross-sectional study, we examined seasonal effects on brain glucose metabolism, which we measured using 18F-fluorodeoxyglucose-PET in 97 healthy participants. To maximize the sensitivity of regional effects, we computed relative metabolic measures by normalizing the regional measures to white matter metabolism. Additionally, we explored the role of rest-activity rhythms/sleep-wake activity measured with actigraphy in the seasonal variations of regional brain metabolic activity. We found that seasonal variations of cerebral glucose metabolism differed across brain regions. Glucose metabolism in prefrontal regions increased with longer daylength and with greater day-to-day increases in daylength. The cuneus and olfactory bulb had the maximum and minimum metabolic values around the summer and winter solstice respectively (positively associated with daylength), whereas the temporal lobe, brainstem, and postcentral cortex showed maximum and minimum metabolic values around the spring and autumn equinoxes, respectively (positively associated with faster daylength gain). Longer daylength was associated with greater amplitude and robustness of diurnal activity rhythms suggesting circadian involvement. The current findings advance our knowledge of seasonal patterns in a key indicator of brain function relevant for mood and cognition. These data could inform treatment interventions for psychiatric symptoms that peak at specific times of the year.

Urban life and sunshine: Equitable sunlight resource allocation among different consumer groups?

Owing to the significant role of sunlight hours in human survival, it is crucial to assess the fairness of sunlight resource allocation among different socioeconomic classes, which is essential for the overall harmonious development of a society. This study focused on selected residential communities in Fuzhou, China, and conducted a simulation analysis of sunlight hours using a Solar Grid Model. Additionally, based on the transaction prices of residential properties in the area, this study employs regression analysis to discuss the current supply and demand of sunlight hours for residences with different price ranges. This study found that properties belonging to the lower-spending group may experience excessive sunlight hours during summer. An increase of one hour in sunlight hours on the summer solstice is associated with a decrease of approximately 45,000 RMB in the total property price. In contrast, the higher-spending group is more likely to face insufficient sunlight during winter, and an increase of one hour in sunlight hours on the winter solstice is associated with an approximate 28,000 RMB rise in the total property price. Furthermore, the study found that controlling the size of the property area for medium- to low-priced residential properties within a range of 113 m2 enables better utilization of sunlight resources. In contrast, high-priced residences, if designed with large protrusions, are prone to wasting sunlight resources. This study employed a novel approach to simulate and replicate the current sunlight conditions in urban architectural clusters. For the first time, this study systematically analyzed variations in the demand for sunlight hours across different socioeconomic groups, using property prices as references. Finally, this study summarizes the typical characteristics of sunlight design issues related to residential sample variations and proposes corresponding solutions.