Sunlight Duration Research Articles

Associations between outdoor temperature and bright sunlight with metabolites in two population-based European cohorts

Background and aimsOutdoor temperature and bright sunlight may directly and/or indirectly modulate systemic metabolism. We assessed the associations between outdoor temperature and bright sunlight duration with metabolomics. Methods and resultsCross-sectional analyses were undertaken in non-diabetic individuals from the Oxford BioBank (OBB; N = 6368; mean age 47.0 years, males 44%) and the Netherlands Epidemiology of Obesity (NEO; N = 5916; mean age 55.6 years, males 43%) study. Data on mean outdoor bright sunlight and temperature were collected from local weather stations in the week prior to blood sampling. Fasting serum levels of 148 metabolites, including 14 lipoprotein subclasses, were measured using NMR spectroscopy. Linear regression analyses were performed to assess the associations between mean outdoor temperature and bright sunlight duration with metabolomics adjusted for age, sex, body mass index, season and either outdoor temperature or bright sunlight. A higher mean outdoor temperature was associated with increased serum concentrations of lipoprotein (sub)particles (β (SE) = 0.064 (0.018) SD per 5 °C, p = 5.03e−4) and certain amino acids such as phenylalanine (0.066 (0.016) SD, p = 6.44e−05) and leucine (0.111 (0.018) SD, p = 1.25e−09). In contrast, longer duration of bright sunlight was specifically associated with lower concentrations of very low-density lipoprotein (sub)particles (e.g., VLDL cholesterol (−0.024 (0.005) SD per 1-h bright sunlight, p = 8.06e−6)). The direction of effects was generally consistent between the OBB and NEO, although effect sizes were generally larger in the OBB. ConclusionsIncreased bright sunlight duration is associated with an improved metabolic profile whilst higher outdoor temperature may adversely impact cardiometabolic health.

Application of Rice Husk Silicate Extract to Increment Growth of Indoor Hydroponic Lettuce

The utilization of backyard or front yard for the cultivation of lettuce under hydroponics system is faced with a limited sunlight duration obtained by plants due to the shadow of buildings and other city infrastructure. This research aimed to overcome the limited sunlight by supporting various concentrations of rice husk extract. The experimental research method was used by a complete randomized design consisted of four treatments: A = without the application of silica extract, B = 10%, C = 20% and D = 30% silica extract of rice husk. Each treatment was repeated six times so that there were 24 experimental units obtained. The parameters measured were the main parameters (plant height, number of leaves, plant fresh weight) and secondary parameters (room temperature, room humidity, pH, electrical conductivity (EC), nutrient volume). The data were then analyzed by variance analysis at 5% significant level and Duncan multiple range test at 5% significant level. The results showed that the application of rice husk silica extract 10-30% concentration was not significantly different compared to without the application of rice husk silica extract. The application of rice husk silica extract has not been able to increase the growth of lettuce in conditions of light intensity lower than 4,500 lx.

Influence of TiO2 Nanoparticles Addition on the Hydrophilicity of Cementitious Composites Surfaces

The effect of the use of TiO2 nanoparticles in the production of cementitious composites, worldwide already known, represents an area of interest for the development of materials with self-cleaning capacity; antimicrobial, antibacterial, antifungal properties; and to contribute to the reduction of environmental pollution. This paper aims to analyze the influence that TiO2 nanoparticles have on the cementitious matrix regarding hydrophilicity, this being one of the two main parameters of the self-cleaning mechanism. Experimental tests, conducted by using the indirect method of measuring the surface water absorption, indicated that an addition of 3%-6% (relative to the amount of cement) of TiO2 nanoparticles is effective in terms of increasing the surface hydrophilicity of the cementitious composites. An excess of TiO2 nanoparticles in the composite matrix (10% TiO2 nanoparticles relative to the amount of cement) not only does not improve surface performance in terms of hydrophilicity, but also reduces them. However, in practice on a case-by-case basis, an analysis is required regarding the optimal amount of nanoparticles used as an addition in the mix-design of the cementitious materials that are intended to induce the quality of self-cleaning process, depending on the intended use, climate, degree and duration of sunlight, and so on.

Lunar polar exploration mission for water prospection - JAXA's current status of joint study with ISRO

Currently, several polar explorations of the Moon are planned, because it has been suggested that water ice might be present in the lunar polar region based on remote sensing observation of the lunar surface using a neutron spectrometer and visible to infrared spectrometer. However, the precise amount and state of the water ice are still unknown. At the Japan Aerospace Exploration Agency (JAXA), we are also studying exploration of the lunar surface for resources, especially cold-trapped volatile such as water ice using a rover. Volatile materials are expected to be useful for future human activity on the Moon and there is strong interest in the origin and concentration mechanism of the water ice. Additionally, the polar regions are among the best candidates for long-term activity because of their long sunlight duration. To realize the mission, we are currently developing various technologies peculiar to exploration of lunar polar regions. This paper details the present status of the Japanese Lunar Polar Exploration Mission.

Variability of Sunlight Duration in Tomsk in 1961–2018

Variations in the sunlight duration (SLD) in Tomsk are analyzed for the period from 1961 to 2018 and separately for 1961–1990 and 1981–2010. Data on clouds and total solar radiation obtained at the TOR-station of IAO SB RAS in 1996–2018 are used. The actual long-term monthly mean SLD ranges from 44 h in December to 317 h in June–July. The analysis of the long-term variation in SLD shows its increase from 1961 to 1989 and its decrease starting from 1999 due to an increase in the low cloud cover and high frequency of continuous clouds. The SLD in Tomsk in the modern period has increased relative to the historical period. Regression equations between SLD and the total solar radiation (Q) are derived.

Optimization of harvesting solar cell energy based on MPPT to be applied during the rainy season in the tropics

Energy harvesting systems in solar cells require control to get maximum power, the maximum power control system is maximum power point tracking (MPPT). Energy efficient and effective harvesting is needed to avoid the energy absorbed by the control system. MPPT method with the Perturb and Observe (p&o) algorithm system. P&O method is a change in the value of a certain voltage and looking at the current value, this method is very effective to get the maximum power produced by solar cells. Energy that is absorbed by solar cells during the rainy season is very limited because the intensity and duration of sunlight to the surface of the solar cells is very small, therefore harvesting energy with the MPPT system can produce effective energy.

Variability of sunlight duration in Tomsk in 1961-2018

Variability of sunlight duration in Tomsk in 1961-2018

Development of the layout method for a high-rise housing complex using parametric algorithm

ABSTRACTAn algorithm-based parametric design method was developed to generate the layout of a high-rise housing complex with improved sunlight access and compliance with the relevant building code restrictions in South Korea. Integrated with computer-aided modelling and simulation, the algorithm automatically arranges multiple apartments according to their height, separation, the shaded area between adjacent buildings and setbacks from site boundaries. The algorithm was then implemented in three high-rise housing complexes across South Korea to validate its feasibility. In all three cases, the algorithm generated housing layouts that satisfied the considered building regulations and improved overall sunlight exposure conditions. Particularly, lower-density housing with fewer buildings or floors were found to be more effective in allowing sunlight access: more housing units were included in the longest sunlight exposure duration whereas fewer units were included in the shortest sunlight duration. The proposed parametric approach allows the effective execution of both diverse experiments in housing design layouts and assessments of layouts’ sunlight access conditions, enhancing sustainable decision-making in the design process.

The effects of daily meteorological perturbation on pregnancy outcome: follow-up of a cohort of young women undergoing IVF treatment

BackgroundHuman reproduction follows a seasonal pattern with respect to spontaneous conception, a phenomenon wherein the effect of meteorological fluctuations might not be unique. However, the effect of seasonal variations on patients who underwent in vitro fertilization (IVF) treatment is unclear. We aimed to evaluate the effects of meteorological variation on the pregnancy rate in a cohort undergoing IVF treatment by performing multivariable analyses.MethodsWe conducted a cohort study in a sub-tropical region with prominent seasonal variations (2005–2016). Women aged < 35 years who were treated with a long ovarian stimulation protocol and underwent fresh embryo transfer (ER) were included. Data on gonadotropin administration (CYCL), oocyte retrieval (OR), ER, and pregnancy outcomes were prospectively recorded. For each patient, the daily average of meteorological data (temperature, humidity, sunlight duration, solar radiation) was recorded from the date of CYCL to ER. Multiple logistic regression analysis adjusted for age, fertilization method, year of the cycle, gonadotropin dose, and transferred embryo grade was performed to determine the relationship between the meteorological parameters and clinical pregnancy. Patients with one successful cycle and one failed cycle were subtracted for a case-control subgroup analysis through mixed effect logistics regressions. Time-series analysis of data in the epidemic level was conducted using the distributed lag linear and non-linear models (DLNMs).ResultsThere were 1029 fresh cycles in 860 women (mean age 31.9 ± 2.0 years). Higher mean temperature from CYCL to OR (adjusted odds ratio [aOR] 1.04; 95% confidence interval [CI] 1.01–1.07, P = 0.01) increased the odds of pregnancy, while OR to ER did not show any statistical significance. Compared to that in winter, the odds of becoming pregnant were higher during higher temperature seasons, summer and autumn (aOR 1.47, 95%CI 0.97–2.23, P = 0.07 (marginally significant) and aOR 1.73, 95%CI 1.12–2.68, P = 0.02, respectively). Humidity, sunlight duration, and solar radiation had no effect on the outcome. The subgroup analysis confirmed this finding. The time-series analysis revealed a positive association between temperature and relative risk for pregnancy.ConclusionsIn IVF treatment, the ambient temperature variation alters the pregnancy rates; this aspect must be considered when obtaining patient consent for assisted conception.

Vitamin D Deficiency Among Afghan Adolescents in Kabul.

To determine vitamin D deficiency (25-OH-D level <20 ng/ml) frequency among apparently healthy Afghan adolescents. Cross-sectional analytical study. Pathology Department, French Medical Institute for Mothers and Children (FMIC) Kabul, from June to Sep 2016. Adolescents who reported for analysis of vitamin D level in their sera were included. Age, gender, duration of sun exposure, area of exposed skin, types of living and eating lifestyles were documented. Vitamin D levels were measured by chemiluminescence method, using immunoassay autoanalysers. The participants were divided into five categories according to their serum vitamin D levels as sufficiency: >30-100 ng/ml; insufficiency: >20-29 ng/ml; deficiency: <20 ng/ml; severe deficiency: <10 ng/ml; and intoxication: >150 ng/ml. Participants who had vitamin D intoxication were excluded from the study. Out of 308 cases for final analysis, 202 (65.6%) were females and 106 (34.4%) were males. Of all, 238 (77.3%) had a low level of vitamin D in their sera, whereas 70 (22.7%) had vitamin D sufficiency. Among those having hypovitaminosis D, 107 (45%) had severe deficiency, 81 (34%) had deficiency and 50 (21%) had vitamin D insufficiency. More pronounced lower levels were observed in females. Exposure to sun, use of a sun protector, vitamin D supplements, and vitamin D rich food intake, type of living, skin colour, and BMI of participants were seen as important factors linked to vitamin D levels. Hypovitaminosis D is prevailing among Afghan adolescents, more pronounced in girls. Wearing of traditional clothes, duration of sunlight, type of living and inadequate consumption of vitamin D rich foods are significant determinants of hypovitaminosis D.

Association of ambient fine particulate matter with increased emergency ambulance dispatches for psychiatric emergencies: a time-series analysis

BackgroundAs a top ambient pollutant in urban area, fine particulate matter (PM2·5) has been associated with the occurrence and deterioration of many medical conditions, while few studies have observed the association with psychiatric conditions. We aimed to investigate the association between short-term PM2·5 exposure and psychiatric emergency events, and further explored the variation by age, sex, and seasonal patterns, which have been suggested to be associated with both psychiatric risk and pollutant toxicity. MethodsWe used time-series analysis to investigate the association between short-time exposure (0–3 days) of PM2·5 and emergency ambulance dispatches for psychiatric emergencies in Beijing, one of the most polluted cities in China during the study period. We did stratified analyses to examine the effects of age, sex, and seasonal pattern. FindingsBetween 2008 and 2014, 158 634 psychiatric emergencies were recorded. Every 10 μg/m3 increase of the PM2·5 concentration was associated with a 0·12% increase of the same-day overall psychiatric emergencies (95% CI 0·03–0·22; p=0·013) and a 0·12% increase of the suicide-related psychiatric emergencies at lag 2 (2 days after PM2·5 exposure; 0·01–0·24; p=0·041). The associations remained when adjusted for sunlight duration. The age effect that children (<18 years) were more likely to be involved in suicide-related psychiatric emergencies after PM2·5 exposure than adults (18–64 years) was significant (percentage change for children vs adults of 0·84% vs 0·07% at lag 3; p=0·013). No significant association was found among the older population (≥65 years; p=0·050–0·825). However, sex and seasonal effects were not statistically significant on the PM2·5 and psychiatric emergencies association (p=0·052–0·999). InterpretationWe found a positive association between acute PM2·5 exposure and increased psychiatric emergency presentations as indicated by emergency ambulance dispatches data. Children were more vulnerable to acute PM2·5 elevation and developed psychiatric problems, especially suicide. We suggest that preventive attention for psychiatric emergencies should be paid after acute PM2·5 elevation, particularly to children. FundingNational Natural Science Foundation of China (81801344), China Postdoctoral Science Foundation (189826), Postdoctoral Fellowship of Peking-Tsinghua Center for Life Sciences, and the Swedish Research Council (2015-06372).

Ambient fine particulate matter is associated with increased emergency ambulance dispatches for psychiatric emergencies

AimsAs a top ambient pollutant in urban area, fine particulate matter (PM2.5) has been associated with the occurrence and deterioration of many medical conditions, while limited studies have observed the association with psychiatric conditions. This study aimed to investigate the association between short-term PM2.5 exposure and psychiatric emergency events, and further explored the variation by age, sex and seasonal patterns, which have been suggested to be associated with both psychiatric risk and pollutant toxicity. MethodsWe used time-series analysis to investigate the association between short-term exposure of PM2.5 and emergency ambulance dispatches for psychiatric emergencies (EPE) (n = 158634) in Beijing, one of the top polluted cities in China during the study period between 2008 and 2014. Stratified analyses were conducted to examine the effects of age, sex and seasonal pattern. ResultsEvery 10 μg/m3 increase of the PM2.5 concentration was associated with a 0.12% increase of the same-day overall EPE (95% CI: 0.03–0.22%, p = 0.013) and a 0.12% increase of the suicide-related EPE at lag 2 (95%CI: 0.01–0.24%, p = 0.041). The associations remained when adjusted for sunlight duration. An age effect was observed where children (age <18) showed a higher risk of suicide-related EPE after PM2.5 exposure compared to adults (18 ≤ age≤64). We did not observe evidence of effect modification by sex and season based on the results of stratified analysis. ConclusionsWe found a positive association between acute PM2.5 exposure and increased psychiatric emergency presentations indicated by emergency ambulance dispatches data. Children were more vulnerable and might develop psychiatric problems including those leading to suicide. Public awareness of the health risks of PM2.5 is important to strengthen current efforts to reduce emissions.

Associations of weather conditions with adolescents' daily physical activity, sedentary time, and sleep duration.

Weather has been recognized as an environmental factor that affects daily activities. However, the effects of a humid subtropical climate on daily activity behavior are unclear. This study investigated the associations of weather conditions with physical activity (PA), sedentary time (ST), and sleep duration in a sample of 740 Hong Kong adolescents (mean age: 14.7 ± 1.6 years). The activPAL was used to assess the time spent during moderate to vigorous PA (MVPA), ST, and sleep. Weather data (e.g., temperature, relative humidity, rainfall amount, and sunlight duration) were obtained from the Hong Kong Observatory. Linear mixed models were constructed to examine the associations of weather conditions with the durations of MVPA, ST, and sleep on weekdays and weekend days, respectively. The analysis included valid data from 561 students (51.9% male). Among Hong Kong adolescents, a higher relative humidity was associated with reduced MVPA on weekdays and weekends, more ST on weekdays, and a longer sleep duration on weekends. A longer duration of sunlight induced less MVPA on weekends, but a longer sleep duration on weekdays. On weekends, higher temperatures correlated with increases in MVPA and ST but a decrease in sleep duration. Rainfall correlated inversely with sleep duration and positively with ST on weekdays. The associations of rainfall with MVPA exhibited opposite trends on weekdays and weekends. In summary, the relationships between weather conditions and daily activities exhibited day-type patterns. The findings suggest that environment-controlled indoor PA should be recommended during weather conditions of high relative humidity and higher temperatures.

An experimental investigation on solar powered solid desiccant air conditioning (SPSDAC) based on regenerative evaporative cooling system with PCM unit

ABSTRACT A solar powered solid desiccant air conditioning (SPSDAC) with PCM unit was explored for cooling purposes for the duration of sunlight and sunset hours. Two unique modes of the indirect evaporative cooler (IEC) was adopted during the operation of the SPSDAC. During mode-1, the water circulated through the copper coil and annular space of the hollow circular pipe was vacant. Whereas in mode-2, the water circulates through copper coil and annular space. It was concluded that COP of the system is more than the exergy efficiency and exergy efficiency varied from 1.83% to 1.99%. The desiccant wheel thermal effectiveness (28.81% and 46.06%) is lower than the indirect and direct evaporative cooler effectiveness. The setup under mode-2 is advantageous as compared to mode-1. The pay back time of the setup is 23.2 months. The mean overall thermal storage capacity of the system in mode-1 is 1796.1 W whereas in mode-2 is 1817.7 W.

A 3D spatial data model of the solar rights associated with individual residential properties

Increased residence in high-rise buildings has aroused demand for sunlight or sunlight duration because a lack of sunlight may lead to negative effects on the mental health of the residents of high-rise buildings. To address this issue, many countries have already enacted laws, regulations and standards that ensure solar rights for residents by guaranteeing a certain duration of sunlight. However, feasible methods that clearly describe the temporal-spatial properties of solar rights for residential buildings are presently lacking, especially for individual housing units distributed in high-rise buildings. Consequently, no relevant data model exists in any current cadastral database. This study presents a 3D data model that incorporates a range of data elements to represent the temporal-spatial extent of solar rights in the context of the current legal system of China. Using existing legal stipulations and spatial features, solar rights are classified into solar easements and neighbouring solar rights, which are separately described by geometric elements developed from the relevant legal stipulations. In addition, the geometric elements of the model are systematically integrated with existing property elements to enable the description of solar rights associated with individual residential properties. To enable the use of this model in a wide range of applications, the model is extended from the Land Administration Domain Model (LADM) and implemented using CityGML application domain extensions (ADEs). The experiments described in this study demonstrate the utility of the 3D data model for the spatial clarification of the solar rights associated with individual 3D properties.

Incidence of dengue fever, climate and vector density in Denpasar

Background and purpose: Until 2009, Denpasar consistently had the highest rates of dengue fever in Bali. However, from 2010 onwards, dengue rates in Denpasar have declined and in 2017 ranked 7th for incidences of dengue fever in Bali. This study aims to determine the trend and the difference of dengue fever incidence rates, vector density and climate for the period 2007-2017.Method: This study employed a secondary analysis of dengue fever incidence rates, climate data and vector density from 2007 to 2017. Data on dengue fever incidence, vector density and the number of field workers (in Indonesia known as juru pemantau jentik or jumantik) carrying out household surveillance of the Aedes aegypti mosquito larvae were obtained from the Denpasar City Health Office. Climate data for 2007-2017 were obtained from the Bali Province Meteorological, Climatological and Geophysical Agency or called Badan Meteorologi, Klimatologi dan Geofisika (BMKG). The data were analyzed by comparing the dengue fever incidence rates, climate data, and vector-density data of the period 2007-2012 and 2013-2017.Results: Incidences of dengue fever in Denpasar have declined since 2013. The number of jumantik in 2007-2012 was 215 and has been increased to 431 since 2013. Climate-related variables found to differ significantly were air temperature, humidity, wind speed and sunlight duration. Air temperature was significantly higher (p=0.034) in 2013-2017 with a mean of 27.8oC compared to the period of 2007-2012 with a mean of 27.5oC. Humidity was significantly lower (p&lt;0.01) in 2013-2107 with a mean of 78.0% compared to the period of 2007-2012 with a mean of 79.8%. Wind speed was significantly higher (p&lt;0.01) in 2013-2017 with a mean of 6.4 knots compared to the period of 2007-2012 with a mean of 5.6 knots. Sunlight duration was significantly lower (p=0.005) in 2013-2017 with a mean of 65.0% compared to the period of 2007-2012 with a mean of 73.0%. Rainfall was lower in 2013-2017 with a mean of 154.8 mm compared to the period of 2007-2012 with a mean of 171 mm, however, the difference was not significant (p=0.569). The proportion of larva-free households was significantly higher (p=0.001) in 2013-2017 (96.9%) compared to the period of 2009-2012 (95.3%). The data of house index (HI), container index (CI) and Breteau index (BI) cannot be compared between these two periods because they are only available for 2013-2017.Conclusion: There has been a decrease in the incidence of dengue fever in Denpasar from 2013-2017 compared to 2007-2012. This is likely to be related to the performance of jumantik in the implementation of vector control programme (VCP) in Denpasar.

Synthesis and Bioactivity of TiO2/PPy Micelle with Pachyrhizus erosus Extract as UV Absorbent Material

Indonesia is a tropical country with high intensity and duration of sunlight throughout over year. The condition causes the average UV index in Indonesia is at the level of 9 up to 11+ so that the power of the sun is extreme invade the human body. This condition makes Indonesia one of the countries with the highest UV index in the world. UV rays exposure can be harmful to humans and become one of the most significant factors causing the existing of skin cancer. Researchers have studied many efforts. Unfortunately, the use of oxidic nanoparticles combined with natural products is not yet explored comprehensively. TiO2 nanoparticles are materials that have excellent absorbability of UV light. In this study the TiO2 nanoparticles as core and combined with Polypyrrole polymer as shell form a micelle structure. The modification of TiO2 nanoparticles with Polypyrrole aims to enhance its UV protection, biocompatibility, and nontoxicity on the body. The addition of Pachyrhizus erosus extract as an enhancer of the efficacy of micelle as UV absorbent agent because it has the phenolic to skin softening properties. The synthesis of micelle TiO2/PPy was performed using in situ method, followed by stirring and sonication process to mix the Pachyrhizus erosus extract with micelle. The XRD analysis of Micelle synthesis shows that the addition of polypyrrole polymer does not affect the crystallinity of TiO2 nanoparticles. The results of testing the antibacterial properties of sunblock samples showed a clear zone with glycerine solvent.

Exploring Outdoor Solar Potential in High-Density Living: Analyzing Direct Sunlight Duration for Urban Agriculture in Seoul’s Residential Complexes

Urban agriculture has become a favored activity in many cities around the world. This study explores how urban agriculture’s potential can be maximized in Seoul, South Korea, a city characterized by high-density residential complexes. It selects six existing residential complexes with representative site typologies and diverse density levels. The study’s aim is to assess the impact of various typology and density settings on percentages of ground-level surface with direct sunlight above certain thresholds during warmer seasons when crops can grow. DIVA-for-Rhino is used for simulation. The findings suggest that parallel typologies and lower density levels offer the best performance, while other combinations show mixed results. This study could benefit citizens and policymakers to facilitate urban agriculture practices around the world by suggesting feasible solutions for high-density residential developments.

Influence of weather on seizure frequency — Clinical experience in the emergency room of a tertiary hospital

IntroductionSome patients with epilepsy identify weather as a typical seizure trigger. However, it is yet to be confirmed. Thus, we aimed to evaluate possible relationships between daily meteorological conditions and the daily incidence of seizures. MethodsThis was a retrospective single center study that included adult patients who were admitted to the emergency room of a tertiary hospital in Lisbon, with a seizure, between January and December 2015. The influence of temperature, atmospheric pressure, relative humidity, wind, precipitation, sunlight duration, and the seasons on seizure frequency was evaluated. ResultsThree hundred seven seizure episodes were included (from 286 patients) in a total of 365 days, 117 (38.1%) first unprovoked seizures and 190 (61.9%) with previous seizure episodes. There were 82 days with higher incidence of seizures (≥2) and 171 days without seizures. We found a statistical significant relation between lower ambient temperatures, higher atmospheric pressure, and higher maximum humidity with days with two or more seizures. We also found a statistically significant higher incidence of seizures in the winter days (p-value: 0.001) and in days with lower daylight duration (10.8 vs. 12.7 h; p-value: 0.0001). With the exception of humidity, these findings remained true when analyzing the subgroup of patients with previous seizures, but there was no significant difference in the subgroup of first unprovoked seizures. ConclusionsOur results support the possible influence of the weather on seizure frequency in the overall admissions of the emergency department of a tertiary hospital. In particular, these findings suggest that winter conditions, such as, lower ambient temperatures, higher atmospheric pressure, higher humidity, and reduced sunlight exposure, may have impact in the occurrence of higher incidence of seizures in patients with epilepsy.

Advanced Daily Prediction Model for National Suicide Numbers with Social Media Data.

ObjectiveSuicide is a significant public health concern worldwide. Social media data have a potential role in identifying high suicide risk individuals and also in predicting suicide rate at the population level. In this study, we report an advanced daily suicide prediction model using social media data combined with economic/meteorological variables along with observed suicide data lagged by 1 week.MethodsThe social media data were drawn from weblog posts. We examined a total of 10,035 social media keywords for suicide prediction. We made predictions of national suicide numbers 7 days in advance daily for 2 years, based on a daily moving 5-year prediction modeling period.ResultsOur model predicted the likely range of daily national suicide numbers with 82.9% accuracy. Among the social media variables, words denoting economic issues and mood status showed high predictive strength. Observed number of suicides one week previously, recent celebrity suicide, and day of week followed by stock index, consumer price index, and sunlight duration 7 days before the target date were notable predictors along with the social media variables.ConclusionThese results strengthen the case for social media data to supplement classical social/economic/climatic data in forecasting national suicide events.