A retrospective study: meteorological factors and COVID-19

Background: With the outbreak of novel coronavirus, the global epidemic prevention form is severe. Purpose: This paper aimed to investigate the association between meteorological factors (temperature, precipitation and relative humidity) and the daily new cases in Wuhan. Methods: generalized linear model was built to evaluate the link between daily average temperature and the new cases COVID-19. Spearman rank correlation coefficient was used to investigate the association between temperature, relative humidity, precipitation and the daily new cases COVID-19. Result: The correlation coefficient for daily average temperature, relative humidity, precipitation and NCP were 0.11, -0.083 and 0.17, respectively. The maximal effect of temperature on the new cases NCP appeared on Lag0. Conclusion: The variation of temperature had an effect on the daily new cases.

Temperature and relative humidity are not major contributing factor on the occurrence of COVID-19 pandemic: An observational study in 57 countries

The world searching for hope has already experienced a huge loss of lives due to COVID-19 caused by SARS-CoV-2 started in Wuhan, China. There are speculations that climatic conditions can slowdown the transmission of COVID-19. Findings from the early outbreak indicated the possible association of air temperature and relative humidity in COVID-19 occurrence in China. Current study focused on whether climatic conditions(temperature and relative humidity)are having any influence in the occurrence of COVID-19 when the outbreak has been classified as pandemic. To determine the effect of daily average temperature and average relative humidity on log-transformed total daily cases of COVID-19, polynomial regression as a quadratic term and linear regression were done. Linear regression analysis was also carried out to explore the same effect on selected countries. Present study observed no correlation between the climatic conditions (the daily average temperature and relative humidity) and the number of cases of COVID-19. Similar result was found in relation between daily average temperature and average number of cases per day in country-wise analysis. However, about 93.5% cases of COVID-19 occurred between 1°C to 16°C and the average number of cases per day was lower in high temperature country than low temperature country with exceptions. The minimum effect of summer temperature may not be effective to control the pandemic rather need to apply the control measures of COVID-19.

A two-stage bias correction approach for downscaling and projection of daily average temperature

Reliable projection of climate is essential for climate change impact assessment and mitigation planning. General Circulation Models (GCMs) simulations are generally downscaled into much finer spatial resolution for climate change impact studies at local and regional scales. The objective of the present study is to use a two-stage bias correction approach for downscale and project future changes of daily average temperature. The approach was applied for downscaling and projection of daily average temperature of Senai meteorological station located in Johor Bahru, Malaysia using a GCM of Coupled Model Intercomparison Project Phase 5 (CMIP5) under four representative concentration pathways (RCP) scenarios. The two-stage bias correction method was based on correction in mean factor and variability inflation factor. The model performances were assessed using different statistical measures including mean bias error (MBE), mean absolute error (MAE), root mean square error (RMSE), index of agreement (MD), Nash–Sutcliffe model efficiency (NSE) and coefficient of determination (R2). Results showed that the downscaling method could simulate historical daily average temperature at the station very well. The GCM projected an increase in daily average temperature by 1.4ºC, 2.2ºC, 2.5ºC, and 3.4ºC under RCP2.6, RCP4.5, RCP6.0 and RCP8.5 scenarios, respectively in the end of this century. It is expected that the finding of the study would help in climate change impact assessment and adopting necessary adaptation measures.

Outdoor temperature and survival benefit of empiric potassium in users of furosemide in US Medicaid enrollees: a cohort study

ObjectiveHeat is associated with elevated all-cause mortality, and furosemide-induced potassium depletion might be worsened by heat-induced sweating. Because empiric potassium is associated with a marked survival benefit in users of furosemide at a dose of ≥40 mg/day, we hypothesised that this empiric potassium’s survival benefit would increase with higher temperature (≥24°C).DesignCohort study.SettingOutpatient setting, captured by Medicaid claims, supplemented with Medicare claims for dual enrollees, from 5 US states from 1999 to 2010, linked to meteorological data.Population/ParticipantsFurosemide (≥40 mg/day) initiators among adults continuously enrolled in Medicaid for at least 1 year prior to cohort entry (defined as the day following the dispensing day of each individual’s first observed furosemide prescription).ExposureInteraction between: (1) empiric potassium, dispensed the day of or the day following the dispensing of the initial furosemide prescription, and (2) daily average temperature and daily maximum temperature, examined separately.OutcomeAll-cause mortality.ResultsIn 1:1 propensity score matched cohorts (total n=211 878) that included 89 335 person-years and 9007 deaths, all-cause mortality rates per 1000 person-years were 96.0 (95% CI 93.2 to 98.9) and 105.8 (95% CI 102.8 to 108.9) for potassium users and non-users, respectively. The adjusted OR of all-cause mortality for potassium use declined (ie, its apparent protective effect increased) as temperature increased, from a daily average temperature of about 28°C and a daily maximum temperature of about 31°C. This relationship was not statistically significant with daily average temperature, but was statistically significant with daily maximum temperature (p values for the interaction of potassium with daily maximum temperature and daily maximum temperature squared were 0.031 and 0.028, respectively).ConclusionsThe results suggest that empiric potassium’s survival benefit among furosemide (≥40 mg/day) initiators may increase as daily maximum temperature increases. If this relationship is real, use of empiric potassium in Medicaid enrollees initiating furosemide might be particularly important on hot days.

Associations between ambient temperature and acute myocardial infarction

BackgroundThe associations between incidence of acute myocardial infarction (AMI) and the ambient temperature were mixed in prior studies.MethodsData of 2033 consecutive admissions of AMI in a central tertiary hospital in North China from 1st Jan 2003 to 31st Dec 2011 were collected. The weather data in this period were from the local meteorological department. Based on the ambient temperature information, we defined several ambient temperature indices, including daily average temperature, extremely low temperature, and daily temperature range, then characterized the independent associations between them and the incidence of AMI.ResultsThe daily average temperature one day before was independently associated with AMI incidence rate: a rise of 5°C of the daily average temperature led to a 5% decrease in AMI admissions. Daily average temperature and temperature range two days before were independently associated with AMI incidence rate: a rise of 5°C of the daily average temperature led to a fall of 6% in AMI admissions, and a rise of 2°C of the daily temperature range led to a rise of 4% in AMI admission.ConclusionLow ambient temperature has substantial association with AMI, and can play an important role in warning and forecasting the incidence.

Effect of Supplementary Curing after Steam-Curing on Performance of Concrete

When the low strength grade of steam-curing concrete is produced, the temperature which the concrete leaves steam-curing kiln is about 20°C commonly. The temperature difference is too large between the environmental temperature and the temperature which the concrete leaves steam-curing kiln when the daily average temperature drops to 10°C. Because the steam-curing concrete is cooled rapidly, a large of crack will be produced in concrete and the internal structure of concrete will be damaged normally. Then the performance of concrete will be influenced badly. In order to improve the negative effect on concrete by steam curing, the different supplementary curing is used after steam curing. The C30 concrete is made in this research. The daily average temperature is 5°C~10°C and the minimum temperature is-6°C during the test. After the concrete is formed, it is placed in 20°C environment for 2h first. Then the concrete is heated to 55°C in 2h and maintained for 8h in the steam-curing kiln. In the end, the concrete is cooled to 20°C in 3h. After steam curing, the standard curing and covering by wet fabric or film outside are used separately for concrete. The supplementary curing time is 1d, 2d, 3d and 4d. Then the concrete is placed in natural environment to 28d. The microstructure of hydration products are observed by electron microscope. The density of concrete is analyzed by the result of the 28d saturated water content, softening factor and 28d rapid carbonation depth. The mechanical properties of concrete are researched by the result of the 28d strength. When the concrete adopts standard curing or covering by film after steam-curing, the saturated water content and 28d rapid carbonation depth of the concrete will reduce, but the softening factor and 28d strength of the concrete will increase with the time. The performance of concrete which adopts covering by wet fabric after steam-curing is worse than that adopting standard curing. At the same time, the saturated water content and softening factor of concrete change little. Covering by wet fabric is worse than no covering or similar. In the test environment, the performance of the steam-curing concrete with each supplementary curing is worse than that of the concrete with standard curing. The standard curing is the best supplementary curing in this test. But covering by film is a worthy supplementary curing from economy and practicability. Covering by film for 4d, the 28d strength of steam-curing concrete is 87 percent of that of the concrete with standard curing and exceeds Design grade. Its saturated water content is 1.50% and softening factor is 0.932. Its rapid carbonation depth is close to that of the concrete with standard curing and its microstructure of hydration products is preferable.