Cumulative Effects Of Temperature Research Articles

Town gas daily load forecasting based on machine learning combinatorial algorithms: A case study in North China

Town gas daily load forecasting based on machine learning combinatorial algorithms: A case study in North China

Direct and indirect cumulative effects of temperature, nutrients, and light on phytoplankton growth.

Temperature and resource availability are pivotal factors influencing phytoplankton community structures. Numerous prior studies demonstrated their significant influence on phytoplankton stoichiometry, cell size, and growth rates. The growth rate, serving as a reflection of an organism's success within its environment, is linked to stoichiometry and cell size. Consequently, alterations in abiotic conditions affecting cell size or stoichiometry also exert indirect effects on growth. However, such results have their limitations, as most studies used a limited number of factors and factor levels which gives us limited insights into how phytoplankton respond to environmental conditions, directly and indirectly. Here, we tested for the generality of patterns found in other studies, using a combined multiple-factor gradient design and two single species with different size characteristics. We used a structural equation model (SEM) that allowed us to investigate the direct cumulative effects of temperature and resource availability (i.e., light, N and P) on phytoplankton growth, as well as their indirect effects on growth through changes in cell size and cell stoichiometry. Our results mostly support the results reported in previous research thus some effects can be identified as dominant effects. We identified rising temperature as the dominant driver for cell size reduction and increase in growth, and nutrient availability (i.e., N and P) as dominant factor for changes in cellular stoichiometry. However, indirect effects of temperature and resources (i.e., light and nutrients) on species' growth rates through cell size and cell stoichiometry differed across the two species suggesting different strategies to acclimate to its environment.

Investigating the impact of weather on stroke in summer.

The objective of this study is to explore how changes in weather contribute to an increase in hospital admissions for stroke in summer. We collected 96,509 cases of stroke hospitalization data in Tianjin from 2016 to 2022 summer, along with corresponding meteorological data. The generalized additive model and distributed lag nonlinear model were used to analyze the lag and cumulative effects of temperature on stroke hospitalization. The research results show both the cold effect and the heat effect in summer would increase the risk of hospitalization. The effect of daily maximum temperature on stroke hospitalization was immediate when the temperature was higher, and delayed when the temperature was lower. However, the risk of stroke hospitalization increased more significantly with increasing temperature than with decreasing temperature. In the presence of one or more of the following three weather changes: sharp temperature increase, sharp temperature decrease, continuous high temperature, the daily number of stroke inpatients were higher than the average in the same period. 83% of the Inpatient-heavy events within the study period were caused by a combination of dramatic temperature changes and continuous high temperatures. In 48% of Inpatient-heavy events, continuous high temperature weather above 30℃ for at least 4 consecutive days were observed. And 55% of high temperature weather was accompanied by high humidity. When the daily relative humidity was greater than 70% and the daily maximum temperature was between 26 and 28℃ or more than 34℃, or the daily maximum temperature changes over 10℃ within 48h, the number of daily inpatients was more than 1.2 times of the average daily inpatients. More attention should be paid to the combined effects of continuous high temperature and sudden temperature changes in summer stroke prevention.

Association between ambient temperature and hospitalizations for urolithiasis in four counties of Ganzhou, China

ABSTRACT We collected meteorological and urolithiasis-related hospitalization data from four counties in Ganzhou City for 2018–2019 and used the DLNM method to assess the lagged and cumulative effects of temperature on urolithiasis hospitalizations and obtain the total effect after meta-combination. Based on the nonlinear association between temperature and urolithiasis hospitalizations, the relative risk of overall high temperature (30℃) was 2.10 (95% CI: 1.07-4.10). No statistically significant difference (p = 0.07) was observed between males (RR = 2.04, 95% CI: 1.42-2.94) and females (RR = 1.45, 95% CI: 1.09-1.92) for the heat effect, which was higher in the ≥ 60 years age group (RR = 3.18, 95% CI: 1.76-5.76) than in the < 60 years age group (p = 0.007). High temperatures increased the risk of hospitalization for urolithiasis in Ganzhou, China, and the risk was greatest for individuals aged 60 and above, with similar risks observed across counties and genders.

Beyond a single temperature threshold: Applying a cumulative thermal stress framework to plant heat tolerance.

Most plant thermal tolerance studies focus on single critical thresholds, which limit the capacity to generalise across studies and predict heat stress under natural conditions. In animals and microbes, thermal tolerance landscapes describe the more realistic, cumulative effects of temperature. We tested this in plants by measuring the decline in leaf photosynthetic efficiency (FV/FM) following a combination of temperatures and exposure times and then modelled these physiological indices alongside recorded environmental temperatures. We demonstrate that a general relationship between stressful temperatures and exposure durations can be effectively employed to quantify and compare heat tolerance within and across plant species and over time. Importantly, we show how FV/FM curves translate to plants under natural conditions, suggesting that environmental temperatures often impair photosynthetic function. Our findings provide more robust descriptors of heat tolerance in plants and suggest that heat tolerance in disparate groups of organisms can be studied with a single predictive framework.

Intra-Annual Cumulative Effects and Mechanisms of Climatic Factors on Global Vegetation Biomes’ Growth

Previous studies have shown that climate change has significant cumulative effects on vegetation growth. However, there remains a gap in understanding the characteristics of cumulative climatic effects on different vegetation types and the underlying driving mechanisms. In this study, using the normalized difference vegetation index data from 1982 to 2015, along with accumulated temperature, precipitation, and solar radiation data, we quantitatively investigated the intra-annual cumulative effects of climatic factors on global vegetation biomes across climatic zones. We also explored the underlying driving mechanisms. The results indicate that precipitation has a longer intra-annual cumulative effect on vegetation, with effects lasting up to 12 months for large percentages of most vegetation biomes. The cumulative effect of solar radiation is mostly concentrated within 0–6 months. Temperature has a shorter cumulative effect, with no significant cumulative effect of temperature on large percentages of tree-type vegetation. Compared to other vegetation types, evergreen broadleaf forests, close shrublands, open shrublands, savannas, and woody savannas exhibit more complex cumulative climatic effects. Each vegetation type shows a weak-to-moderate correlation with accumulated precipitation while exhibiting strong-to-extremely-strong positive correlations with accumulated temperature and accumulated solar radiation. The climate-induced regulations of water, heat, and nutrient, as well as the intrinsic mechanisms of vegetation’s tolerance, resistance, and adaptation to climate change, account for the significant heterogeneity of cumulative climatic effects across vegetation biomes in different climatic zones. This study contributes to enriching the theoretical understanding of the relationship between vegetation growth and climate change. It also offers crucial theoretical support for developing climate change adaptation strategies and improving future “vegetation-climate” models.

Precipitation controls the time-lag and cumulative effects of hydrothermal factors on the end of the growing season in a semi-arid region of China.

Climate change has a substantial influence on the end of the growing season (EOS). The time-lag and cumulative effects are non-negligible phenomena when studying the interactions between climate and vegetation. However, quantification of the temporal effects of climatic factors on the EOS in the context of changing hydrothermal patterns remains scarce. Based on the Moderate Resolution Imaging Spectroradiometer (MODIS) fraction of absorbed photosynthetically active radiation (FPAR), this study first inverted the EOS of typical steppe vegetation in a semi-arid region of China and then quantified the time-lag and cumulative effects of monthly total precipitation (PRE) and monthly average temperature (TEM) on the EOS during 2003-2022. The results showed that a turning point occurred in 2011, when the EOS displayed an advancing trend until 2011, followed by a delayed trend. Accordingly, the climatic background has changed from warming and drying conditions during 2003-2011 to warming and wetting conditions during 2011-2022. The time-lag scales of PRE and TEM on the EOS decreased from 2- and 4-month scales during 2003-2011, respectively, to 1- and 2-month scales during 2011-2022, respectively. The time-lag degree of the hydrothermal factors on the EOS weakened with increased precipitation. The cumulative time scales of the EOS response to PRE and TEM were mainly concentrated within 1-month during different time periods, but the EOS was more sensitive to short-term precipitation. The time lag and cumulative partial correlation coefficient of PRE to EOS changed from mainly negative regulation during 2003-2011 (39.2% and 50.0%, respectively) to mainly positive regulation during 2011-2022 (67.8% and 93.7%, respectively). The time-lag and cumulative effects of TEM on the EOS were positive with the precipitation and temperature gradient under a warming and wetting climate, which indicated that increased precipitation was a prerequisite for temperature to induce a delayed EOS in the semi-arid study region. This study emphasizes the important role of precipitation in regulating the EOS response to hydrothermal factors in semi-arid regions.

평균온도와 자살 사망률의 연관성

Temperature increase due to climate change is approaching as a practical problem. A recent study showing that temperature increase can trigger suicide is noteworthy in Korea, where the suicide rate is high. Distributed lag (DL) models have been used in many epidemiological studies to evaluate the cumulative effect of temperature on suicide. Although the effect of temperature on suicide differs by age and gender, DL models have been frequently used at the aggregated level. We used a age-specific DL models to confirm the effect of temperature by age. This model uses data from different ages to estimate age-specific DL effects. We used the model to explore the association between the standardized suicide mortality ratio and mean temperature by age in Seoul from 2010 to 2019. As a result, short-term exposure to high temperature was significantly associated with an increase in suicide mortality in those aged 65 years or older and those aged 35-64 years. On the other hand, 10-34 years of age showed a significant association with a decrease in suicide mortality. As the lag days increased, the effect of temperature decreased. The cumulative effect of mean temperature over the lag period of 0-3 days showed a significant association with suicide mortality only in those aged 65 years or older. The association between high temperature and suicide mortality was significantly higher in men than in women. This research method can be used in various ways in other studies to confirm the association between environmental factors and diseases by age.

Correlation Study Between Cooling Load and Temperature Sensitivity Considering the Cumulative Effect of Temperature

To study the correlation between cooling load and air temperature, this paper uses the maximum load comparison method to calculate the cooling load based on the actual load data of the power grid, and uses the temperature correction model to correct the daily maximum temperature, and then establishes a high-order regression model of cooling load and corrected air temperature. The method is applied to the sensitivity analysis of cooling load and air temperature in the Chongqing power grid and sub-regions, and the corresponding change law is obtained, which provides an important reference basis for the production and dispatch, optimal operation, and marketing of the power grid.

Cumulative effects of temperature on blood pressure during pregnancy: A cohort study of differing effects in three trimesters

BackgroundLittle is known about the non-linear cumulative effects of temperature on blood pressure (BP) during pregnancy. We investigated the differing effects of daily ambient temperature on BP for up to 30 days in three trimesters. MethodsThe first, second, and third trimester analyses included 2547, 2299, and 2011 pregnant women, respectively, from a prospective cohort in Nanjing from January 2017 to January 2020. BP was measured at each follow-up visit. The individual daily temperature exposures were calculated for 30 days prior to the follow-up date. The Distributed Lag Non-linear Model was used to investigate the relationship between temperature and BP in each trimester. ResultsTemperatures under 15 °C elevate systolic, diastolic BP, and mean arterial pressure (SBP, DBP, and MAP) in the first trimester, while temperatures above 15 °C reduce SBP in the second and third trimesters. By using Distributed Lag Linear Models, we estimated that with a 1 °C decrease in daily temperature, the SBP and DBP increased by 0.32 (95 % CI: 0.12, 0.52) and 0.23 (95 % CI: 0.07, 0.39) mmHg, respectively, in the first trimester with a 20-day cumulative lag, while with a 1 °C increase in daily temperature, the SBP decreased by 0.23 (0.35, 0.10) mmHg in the third trimester with a 30-day cumulative lag. The significant effects of temperature mainly manifested between 2 and 4 weeks of exposure. ConclusionsTemperature has different effects on BP over three trimesters. Protective measures to reduce cold-related BP rise will help reduce the risk of hypertensive disorders of pregnancy.

Association between ambient temperature and cause-specific respiratory outpatient visits: A case-crossover design with a distributed lag nonlinear model in Lanzhou, China

Little is known about the association between air temperature and causes-specific respiratory diseases (RD), especially in northwest China. A time-stratified case crossover design with a distributed lag nonlinear model (DLNM) was conducted to assess the nonlinear and delayed effects of temperature on total and cause-specific outpatient visits, with analyses stratified by gender and age. The cumulative effects of temperature were irregular M-shaped curves for total and upper respiratory tract infection (URTI), with inverted U-shaped curve for pneumonia, bronchitis and chronic obstructive pulmonary disease (COPD). Positive cold and heat effects were observed for URTI, pneumonia, bronchitis and COPD, bronchitis was most vulnerable to cold but pneumonia was more affected to heat. Heat effects were immediate whereas cold effects were delayed and lasted longer. The magnitude of temperature effects varies greatly by age, gender, and disease. Notably, the cold effect was greater for children aged 0–14 than that of other age groups. This study suggested that both cold and hot temperatures exposure could increase all-cause and cause-specific respiratory outpatient visits in Lanzhou, China. The harmful effect and duration of cold were greater than that of heat, and children aged 0–14 were more sensitive to cold. Protection against extreme temperatures should be strengthened.

Ambient temperature and term birthweight in Latin American cities.

BackgroundExtreme temperatures may lead to adverse pregnancy and birth outcomes, including low birthweight. Studies on the impact of temperature on birthweight have been inconclusive due to methodological challenges related to operationalizing temperature exposure, the definitions of exposure windows, accounting for gestational age, and a limited geographic scope.MethodsWe combined data on individual-level term live births (N≈15 million births) from urban areas in Brazil, Chile, and Mexico from 2010 to 2015 from the SALURBAL study (Urban Health in Latin America) with high-resolution daily air temperature data and computed average ambient temperature for every month of gestation for each newborn. Associations between full-term birthweight and average temperature during gestation were analyzed using multi-level distributed lag non-linear models that adjusted for newborn’s sex, season of conception, and calendar year of child’s birth; controlled for maternal age, education, partnership status, presence of previous births, and climate zone; and included a random term for the sub-city of mother’s residence.FindingsHigher temperatures during the entire gestation are associated with lower birthweight, particularly in Mexico and Brazil. The cumulative effect of temperature on birthweight is mostly driven by exposure to higher temperatures during months 7–9 of gestation. Higher maternal education can attenuate the temperature-birthweight associations.InterpretationOur work shows that climate-health impacts are likely to be context- and place-specific and warrants research on temperature and birthweight in diverse climates to adequately anticipate global climate change. Given the high societal cost of suboptimal birthweight, public health efforts should be aimed at diminishing the detrimental effect of higher temperatures on birthweight.FundingThe Wellcome Trust.

Regional-scale vegetation-climate interactions on the Qinghai-Tibet Plateau

Response and feedback of vegetation growth to climate change are a series biogeophysical processes from local to regional scales. Revealing the vegetation-climate interaction is fundamental to understand the evolution of earth surface system in the context of global climate change. Due to the low temperature and vulnerable biotic and abiotic settings, the alpine ecosystems are sensitive to climate change, peculiarly in the Qinghai-Tibet Plateau (QTP). By combining the climate factors (precipitation and temperature) and vegetation state indicated by the Enhanced Vegetation Index (EVI) data we try to reveal the pertinent temporal reaction mode of vegetation to climate change on the QTP. The vegetation-climate interactions were investigated by using the Granger causality test technique. The prime findings of this study are: (1) vegetation showed a strong sensitivity to warming-wetting climate in most arid and semi-arid areas of the QTP; (2) the reaction patterns of EVI to precipitation show a temporal lag of 0–1 months, which was strongest to the cumulative precipitation within 1–2 months; (3) The time lag effect and cumulative effect of temperature on vegetation both occurred within 1 to 2 months; (4) The unidirectional Granger causes of precipitation and temperature to vegetation accounted for 17.65% and 8.66% of the entire QTP, respectively. This study emphasizes a sensitive response of the vegetation to climate change (precipitation and temperature) in the QTP. Vegetation feedback makes the fluctuations and effects of climate more complicated. The results indicated that more insights into the future forecasting of climate change and vegetation dynamics can be acquired by a specific and comprehensive analysis of vegetation-climate coupled feedback.

Short-term exposure to temperature and all-cause and cause-specific mortality: a study in nine Belgian cities, 2010-2015

BACKGROUND AND AIM: Accumulating epidemiological evidence indicates that high ambient temperatures increase the risk of death. This study aimed to examine the optimum temperatures in Belgium that correspond to minimum mortality, and quantify the relative risks of mortality from all natural causes, and cause-specific causes due to hot and cold non-optimum temperatures. METHODS: A time-stratified case-crossover design fitted with a conditional quasi-Poisson regression model and distributed lag non-linear models were applied to estimate city-specific temperature-mortality associations in nine main Belgian cities, and a random-effect meta-analysis was conducted to pool the estimates. Over the period 2010-2015, a total of 307,859 deaths from natural causes were included. Separate analyses were performed for cause-specific mortality (ischemic heart disease, cerebrovascular, other cardiovascular, chronic obstructive pulmonary disease, other respiratory, and other natural). Analyses were controlled for relative humidity, holidays, long-term and seasonal trends. RESULTS:Considering a cumulative effect of temperature over 21 days before death, both heat and cold were associated with increased mortality risks from all causes. Relative to the minimum mortality temperature (23.1°C, 86.3th centile of the temperature distribution), the pooled estimate of the mortality risk for cold temperature (at -1.7°C, the 1st centile) was 1.32 (95% CI: 1.21-1.44) and 1.21 (95% CI: 1.08-1.36) for hot temperature (at 31.3°C, the 99th centile). When considering a cumulative effect of temperature over 7 days before death, the effect was lower for cold temperature (1.04, 95% CI: 1.00-1.09) but higher for hot temperature (1.33, 95% CI: 1.25-1.41). Adjustment for air pollutants did not change the results. The shapes of the cause-specific related mortality showed various patterns with a clear effect of heat on mortality due to ischemic heart diseases. CONCLUSIONS:This nationwide study provides a comprehensive picture of the non-linear associations between hot and cold temperatures related mortality from cause-specific and all natural causes, in Belgium. KEYWORDS: mortality,temperature,multi-city analysis,causes of death,dlnm

Association between temperature exposure and cognition: a cross-sectional analysis of 20,687 aging adults in the United States

BackgroundOlder adults are particularly vulnerable to the adverse health effects of extreme temperature-related events. A growing body of literature highlights the importance of the natural environment, including air pollution and sunlight, on cognitive health. However, the relationship between exposure to outdoor temperatures and cognitive functioning, and whether there exists any differences across climate region, remains largely unexplored. We address this gap by examining the temperature-cognition association, and whether there exists any variation across climate regions in a national cohort of aging adults.MethodsIn this cross-sectional study, we obtained data on temperature exposure based on geocoded residential location of participants in the REasons for Geographic And Racial Differences in Stroke (REGARDS) study. For each participant, this information was linked to their cognitive scores from Word List Learning and Recall tests to assess cognitive functioning. We used distributed lag non-linear models (dlnm) to model temperature effects over 2 days. Multivariable linear regression was used to compute temperature-cognitive functioning associations, adjusted for important covariates. Region-specific (“Dry”, “Mediterranean/oceanic”, “Tropical” and “Continental”) associations were examined by including an interaction term between climate region and temperature.ResultsAmongst 20,687 individuals (mean age = 67.8; standard deviation = 9.2), exposure to region-specific extreme cold temperatures in the “dry” region (e.g., Arizona) over 2 days was associated with lower cognitive scores (Mean Difference [MD]: -0.76, 95% Confidence Interval [CI]: − 1.45, − 0.07). Associations remained significant for cumulative effects of temperature over 2 days. Extremely cold exposure in the “Mediterranean/oceanic” region (e.g., California) over 2 days was also associated with significantly lower cognitive performance (MD: -0.25, 95% CI: − 0.47, − 0.04). No significant associations were observed for exposure to hot temperatures. Cognitive performance was slightly higher in late summer and fall compared to early summer.ConclusionWe noted adverse cognitive associations with cold temperatures in traditionally warmer regions of the country and improved cognition in summer and early fall seasons. While we did not observe very large significant associations, this study deepens understanding of the impact of climate change on the cognitive health of aging adults and can inform clinical care and public health preparedness plans.

Meteorological factors, governmental responses and COVID-19: Evidence from four European countries

With the global lockdown, meteorological factors are highly discussed for COVID-19 transmission. In this study, national-specific and region-specific data sets from Germany, Italy, Spain and the United Kingdom were used to explore the effect of temperature, absolute humidity and diurnal temperature range (DTR) on COVID-19 transmission. From February 1st to November 1st, a 7-day COVID-19 case doubling time (Td), meteorological factors with cumulative 14-day-lagged, government response index and other factors were fitted in the distributed lag nonlinear models. The overall relative risk (RR) of the 10th and the 25th percentiles temperature compared to the median were 0.0074 (95% CI: 0.0023, 0.0237) and 0.1220 (95% CI: 0.0667, 0.2232), respectively. The pooled RR of lower (10th, 25th) and extremely high (90th) absolute humidity were 0.3266 (95% CI: 0.1379, 0.7734), 0.6018 (95% CI: 0.4693, 0.7718) and 0.3438 (95% CI: 0.2254, 0.5242), respectively. While the DTR did not have a significant effect on Td. The total cumulative effect of temperature (10th) and absolute humidity (10th, 90th) on Td increased with the change of lag days. Similarly, a decline in temperature and absolute humidity at cumulative 14-day-lagged corresponded to the lower RR on Td in pooled region-specific effects. In summary, the government responses are important factors in alleviating the spread of COVID-19. After controlling that, our results indicate that both the cold and the dry environment also likely facilitate the COVID-19 transmission.

Suicide Behavior and Meteorological Characteristic in Hot and Arid Climate

Background: Suicidal behavior is determined by the consequence of an interaction between biological, psychological and sociological factors, as well as between individual and environmental effects. Fluctuations in meteorological factors can modify human behavior and effect suicidal rates. We hypothesize that high temperatures can be associated with an increase rate of suicidal attempts.Methods: We included all patients admitted to Soroka University Medical Center (SUMC) due to suicide attempts between the years 2002-2017 and were residents of Southern Israel. We computed two sets of regression models: a time stratified case-crossover design to control for seasonality and individual differences; then, time-series analyses to calculate the incidence rate ratio (IRR) and the cumulative effect of temperature on the daily incidences of ER admissions after suicide attempts. We stratified the analyses by demographic variables to identify significant individual differencesResults: Suicide attempts were associated with a 5 °C increase during the summer season (OR 1.59, 95% CI 1.22-2.08) and a 5 °C increase in all seasons was associated with those who have made multiple attempts (OR 1.18, 95% CI 1.0005-1.38). The cumulative effect of 5° C increment is associated with more suicide attempts over 2 days (IRR 1.10, 95% CI 0.98; 1.24) and 5 days (IRR 1.04, 95% CI 1.00;1.08). The associations were greater for patients with psychiatric diagnosis and patients with multiple attempts.Conclusion: High temperatures and low amounts of precipitations are evidently of great impact on people's susceptibility to suicidal behavior, especially for individuals who have had a prior suicide attempt.

Cumulative effects of temperature, magnetic field and spin orbit interaction (SOI) on the properties of magnetopolaron in RbCl quantum well

In this work, we investigate the cumulative effects of temperature, spin orbit interaction (SOI) and the magnetic field on properties of the magnetopolaron in RbCl quantum well. The Ground state binding energy (GSBE) of the magnetopolaron in RbCl QW is evaluated using the Lee Low Pine Unitary transformation (LLPUT) and the combination operation method. Numerical results show that, in addition to temperature, the spin orbit interaction affects considerably the GSBE of the magnetopolaron. Also, the transition behavior at threshold values of the temperature as well as the cyclotron frequency is considered. This study reveals that the spin orbit interaction cannot be neglected during the investigation of the nanostructure system.

Ultraviolet Radiation Decreases COVID-19 Growth Rates: Global Causal Estimates and Seasonal Implications

With nearly every country now combating the 2019 novel coronavirus (COVID-19), there is a growing need to understand how local environmental conditions may modify transmission. To date, quantifying seasonality of the disease has been limited by scarce data and the difficulty of isolating climatological variables from other drivers of transmission in observational studies. We combine a spatially-resolved dataset of confirmed COVID-19 cases, composed of 3,235 regions across 173 countries, with local environmental conditions and a statistical approach developed to quantify causal effects of environmental conditions in observational data settings. We find that ultraviolet (UV) radiation has a statistically significant effect on daily COVID-19 growth rates: a standard deviation increase in UV lowers the daily growth rate of COVID-19 cases by approximately 1 percentage point over the subsequent 2.5 weeks, relative to an average in-sample growth rate of 13.2 percent. The time pattern of lagged effects peaks 9-11 days after UV exposure, consistent with the combined timescale of incubation, testing, and reporting. Cumulative effects of temperature and humidity are not statistically significant. Simulations illustrate how seasonal changes in UV have influenced regional patterns of COVID-19 growth rates from January to June. However, total COVID-19 seasonality had indeterminate sign for most regions during this period due to uncertain effects of other environmental variables. Thus, while our findings indicate UV exposure influences COVID-19 cases, a comprehensive understanding of seasonality awaits further analysis.

Suicide behavior and meteorological characteristics in hot and arid climate

BackgroundSuicidal behavior is determined by the consequence of an interaction between biological, psychological and sociological factors, as well as between individual and environmental effects. Fluctuations in meteorological factors can modify human behavior and affect suicidal rates. We hypothesize that high temperatures can be associated with an increase rate of suicidal attempts. MethodsWe included all the patients admitted to Soroka University Medical Center (SUMC) due to suicide attempts between the years 2002–2017 and were residents of Southern Israel. We computed two sets of regression models: first, a time stratified case-crossover design to control for seasonality and individual differences. Results are presented as odds ratio (OR) with confidence interval (CI); and then, time-series analyses to calculate the incidence rate ratio (IRR) and the cumulative effect of temperature on the daily incidences of emergency department (ED) admissions after suicide attempts. We stratified the analyses by demographic variables to identify significant individual differences. ResultsWe identified 3100 attempts, by 2338 patients who lived in Be'er Sheva between 16 and 90 years of age; 421 patients made 2+ attempts. Suicide attempts were associated with a 5 °C increase during the summer season (OR 1.59, 95% CI 1.22–2.08) and a 5 °C increase in all seasons was associated with those who have made multiple attempts (OR 1.18, 95% CI 1.0005–1.38). The cumulative effect of 5 °C increment is associated with more suicide attempts over 2 days (IRR 1.10, 95% CI 0.98; 1.24) and 5 days (IRR 1.04, 95% CI 1.00; 1.08). The associations were greater for patients with psychiatric diagnosis and patients with multiple attempts. In a stratified analysis by individual characteristics we didn't find significant association. ConclusionHigh temperatures and low amount of precipitations are evidently of great impact on people's susceptibility to suicidal behavior, especially for individuals who have had a prior suicide attempt. Our findings indicate the need for public health attention in the summer when temperature increases precipitously over days, especially for those who have made a prior suicide attempt.