scholarly journals A psychrometric model to predict the biological decay of the SARS-CoV-2 virus in aerosols

2020 ◽  
Author(s):  
Clive B. Beggs ◽  
Eldad J. Avital
Keyword(s):  
Air Temperature ◽  
Vapour Pressure ◽  
Half Life ◽  
Analytical Study ◽  
Decay Constant ◽  
Meteorological Data ◽  
Environmental Parameters ◽  
Published Data ◽  
High Degree ◽  
The Impact

AbstractThere is increasing evidence that the 2020 COVID-19 pandemic has been influenced by variations in air temperature and humidity. However, the impact that these environmental parameters have on survival of the SARS-CoV-2 virus has not been fully characterised. Therefore an analytical study was undertaken using published data to develop a psychrometric model to predict the biological decay rate of the virus in aerosols. This revealed that it is possible to predict with a high degree of accuracy (R2 = 0.718, p<0.001) the biological decay constant for SARS-CoV-2 using a regression model with enthalpy, vapour pressure and specific volume as predictors. Applying this to historical meteorological data from London, Paris and Milan over the pandemic period, produced results which indicate that the average half-life of the virus in aerosols was in the region 13-21 times longer in March 2020, when the outbreak was accelerating, than it was in August 2020 when epidemic in Europe was at its nadir. As such, this suggests that changes in virus survivability due the variations in the psychrometric qualities of the air might influence the transmission of COVID-19.

scholarly journals A psychrometric model to assess the biological decay of the SARS-CoV-2 virus in aerosols

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11024
Author(s):  
Clive B. Beggs ◽  
Eldad J. Avital
Keyword(s):  
Air Temperature ◽  
Vapour Pressure ◽  
Half Life ◽  
Analytical Study ◽  
Decay Constant ◽  
Meteorological Data ◽  
Environmental Parameters ◽  
Published Data ◽  
Reasonable Accuracy ◽  
The Impact

There is increasing evidence that the 2020 COVID-19 pandemic has been influenced by variations in air temperature and humidity. However, the impact that these environmental parameters have on survival of the SARS-CoV-2 virus has not been fully characterised. Therefore, an analytical study was undertaken using published data to develop a psychrometric model to assess the biological decay rate of the virus in aerosols. This revealed that it is possible to describe with reasonable accuracy (R2 = 0.718, p < 0.001) the biological decay constant for the SARS-CoV-2 virus using a regression model with enthalpy, vapour pressure and specific volume as predictors. Applying this to historical meteorological data from London, Paris and Milan over the pandemic period, produced results which indicate that the average half-life of the virus in aerosols outdoors was in the region 13–22 times longer in March 2020, when the outbreak was accelerating, than it was in August 2020 when epidemic in Europe was at its nadir. However, indoors, this variation is likely to be much less. As such, this suggests that changes in virus survivability due the variations in the psychrometric qualities of the air might influence the transmission of SARS-CoV-2.

The Influence of Simulated Sunlight on the Inactivation of Influenza Virus in Aerosols

2019 ◽  
Vol 221 (3) ◽  
pp. 372-378 ◽  
Author(s):  
Michael Schuit ◽  
Sierra Gardner ◽  
Stewart Wood ◽  
Kristin Bower ◽  
Greg Williams ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Relative Humidity ◽  
Half Life ◽  
Decay Constant ◽  
Environmental Parameters ◽  
Decay Rates ◽  
Simulated Sunlight ◽  
Aerosol Chamber ◽  
Full Intensity ◽  
The Impact

Abstract Background Environmental parameters, including sunlight levels, are known to affect the survival of many microorganisms in aerosols. However, the impact of sunlight on the survival of influenza virus in aerosols has not been previously quantified. Methods The present study examined the influence of simulated sunlight on the survival of influenza virus in aerosols at both 20% and 70% relative humidity using an environmentally controlled rotating drum aerosol chamber. Results Measured decay rates were dependent on the level of simulated sunlight, but they were not significantly different between the 2 relative humidity levels tested. In darkness, the average decay constant was 0.02 ± 0.06 min−1, equivalent to a half-life of 31.6 minutes. However, at full intensity simulated sunlight, the mean decay constant was 0.29 ± 0.09 min−1, equivalent to a half-life of approximately 2.4 minutes. Conclusions These results are consistent with epidemiological findings that sunlight levels are inversely correlated with influenza transmission, and they can be used to better understand the potential for the virus to spread under varied environmental conditions.

scholarly journals Evaluation of nature-based solutions implementation scenarios, using urban surface modelling

2021 ◽  
pp. 1-42
Author(s):  
Emmanuel Panagiotakis ◽  
Dionysia Kolokotsa ◽  
Nektarios Chrysoulakis
Keyword(s):  
Heat Flux ◽  
Relative Humidity ◽  
Urban Environment ◽  
Air Temperature ◽  
Green Infrastructure ◽  
Model Simulation ◽  
Meteorological Data ◽  
Sensible Heat Flux ◽  
The Impact ◽  
The City

The present paper aims to study the impact of Nature Based Solutions (NBS) on the urban environment. The Surface Urban Energy and Water balance Scheme (SUEWS) is used to quantify the impact of NBS in the city of Heraklion, Crete, Greece, a densely built urban area. Local meteorological data and data from an Eddy Covariance flux tower installed in the city center are used for the model simulation and evaluation. Five different scenarios are tested by replacing the city’s roofs and pavements with green infrastructure, i.e., trees and grass, and water bodies. The NBS impact evaluation is based on the changes of air temperature above 2m from the ground, relative humidity and energy fluxes. A decrease of the air temperature is revealed with the highest reduction (2.3%) occurring when the pavements are replaced with grass for all scenarios. The reduction of the air temperature is followed by a decrease in turbulent sensible heat flux. For almost all cases, an increase of the relative humidity is noticed, accompanied by a considerable increase of the turbulent latent heat flux. Therefore, NBS in cities change the energy balance significantly and modify the urban environment for the citizens' benefit.

scholarly journals Effects of cloudiness on carbon dioxide exchange over an irrigated maize cropland in northwestern China

2011 ◽  
Vol 8 (1) ◽  
pp. 1669-1691 ◽  
Author(s):  
B. C. Zhang ◽  
J. J. Cao ◽  
Y. F. Bai ◽  
S. J. Yang ◽  
L. Hu ◽  
...  
Keyword(s):  
Air Temperature ◽  
Vapour Pressure ◽  
Ecosystem Respiration ◽  
Meteorological Data ◽  
Exchange Process ◽  
Vapour Pressure Deficit ◽  
Northwestern China ◽  
Carbon Dioxide Exchange ◽  
Carbon Uptake ◽  
Carbon Exchange

Abstract. Clouds can strongly influence solar radiation and affects other microclimatic factors (such as air temperature and vapour pressure deficit), and those changed environmental conditions may exert strong effects on carbon exchange between terrestrial ecosystems and the atmosphere. In this study, we analyzed how canopy photosynthesis and ecosystem respiration respond to changes in cloudy conditions, based on two years of eddy-covariance and meteorological data from an irrigated maize cropland in Yingke oasis of northwestern China. The results showed that net carbon uptake was more negative under cloudy than under clear conditions, it indicates that net carbon uptake increased under cloudy days. The rate of ecosystem respiration (Re) decreased under cloudy conditions due to decreased air temperature. However, photosynthesis was suppressed by the decreasing air temperature and vapour pressure deficit (VPD) under cloudy skies. Thus, the enhancement of net carbon uptake under cloudy skies mainly contributed from increasing photosynthesis with diffuse radiation. Those results improve our understanding of the effects of cloud cover on carbon exchange process in maize (C4) cropland, and improve our understanding of the driver improving net carbon uptake under cloudy conditions.

scholarly journals Splash Erosion on Terraces, Does It Make a Difference If the Terracing Is Done before or after a Fire?

Hydrology ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 180
Author(s):  
María Fernández-Raga ◽  
Martinho A. S. Martins ◽  
Elena Marcos Porras ◽  
Roberto Fraile ◽  
Jan Jacob Keizer
Keyword(s):  
Meteorological Data ◽  
Soil Aggregates ◽  
Type Model ◽  
Subsurface Hydrology ◽  
Splash Erosion ◽  
Erosion Rates ◽  
Erosion Processes ◽  
High Degree ◽  
The Impact ◽  
Fire Conditions

Terraces are a common Mediterranean feature influencing soils, slopes and subsurface hydrology; however, little is known about their impact on erosion processes, especially in humid regions. The purpose of this study was to assess how terracing after a fire affected erosion processes such as splash erosion. For 8 months, the study monitored splash erosion in three terraced plots, one plot under pre-fire conditions and the other two under post-fire conditions. Assessment of the impact of the terracing treatment in such plots was carried out by the installation of two different splash erosion quantitative systems: cups and funnels. An analysis of the splash data obtained in 17 rainfall events and meteorological data collected during each one of those periods was then performed. A significant positive correlation between the amount of rainfall and the splash erosion was observed. The two splash sampling systems show a high degree of concordance; however, the funnel-type model seems to be the most appropriate when it comes to preventing loss of splashed soil samples. The post-fire treatment with terracing leads to a smaller stability of surface soil aggregates, causing higher splash erosion rates. Sampling using the funnel system collects three times the amount of splashed soil than that collected by the cup system, although both systems correlate appropriately with the meteorological parameters.

Prospects for the use of the “model budget” in the distribution of equalization grants in Russia

2019 ◽  
pp. 21-38
Author(s):  
Alexander N. Deryugin ◽  
Ilya A. Sokolov
Keyword(s):  
Intergovernmental Relations ◽  
Unfunded Mandates ◽  
Interregional Inequality ◽  
Alternative Approach ◽  
The Russian Federation ◽  
Regional Authorities ◽  
High Degree ◽  
Equalization Grants ◽  
The Impact ◽  
Budget Expenditure

The paper analyzes the impact of the “model budget” on the problems of intergovernmental relations in the Russian Federation: a high proportion of expenditure obligations of regional and local budgets and a high degree of interregional inequality in fiscal capacity and socio-economic development. It was concluded that the planned broader use of the “model budget” will not solve the problem of unfunded mandates and will lead first to a significant reduction in incentives for regional authorities to develop the territorial revenue base, and then to economic slowdown in the country. As an alternative approach to improving intergovernmental relations, options are being considered for adjusting the parameters of the equalization transfers distribution formula, the procedure for determining their total volume and calculating the budget expenditure index. In solving the problem of unfunded mandates, an equally important role is given to the procedure for preparing a financial and economic rationale for draft laws.

Агрономическая эффективность промышленной (голландской) технологии возделывания картофеля

2018 ◽  
Author(s):  
C. Coy ◽  
A.V. Shuravilin ◽  
O.A. Zakharova
Keyword(s):  
Heavy Metals ◽  
Regression Analysis ◽  
Positive Response ◽  
Growth Yield ◽  
Correlation And Regression Analysis ◽  
Yield And Quality ◽  
Quality Of Products ◽  
High Degree ◽  
The Impact

Приведены результаты исследований по изучению влияния промышленной технологии возделывания картофеля на развитие, урожайность и качество продукции. Выявлена положительная реакция растений на подкормку K2SO4 в период посадки. Корреляционно-регрессионный анализ урожайности и качества клубней выявил высокую степень достоверности результатов опыта. Содержание нитратов и тяжелых металлов в клубнях было ниже допустимых величин.The results of studies on the impact of industrial technology of potato cultivation on growth, yield and quality of products. There was a positive response of plants to fertilizer K2SO4 in the period of planting. Correlation and regression analysis of yield and quality of tubers revealed a high degree of reliability of the results of experience. The contents of nitrates and heavy metals in tubers was below the permissible values.

Te inf uence of ergonomic factors on the formation of occupational risk of health disorders of agricultural machine operators

2019 ◽  
Vol 1 (7) ◽  
pp. 400-405
Author(s):  
Tamara A. Novikova ◽  
Aleksey N. Danilov ◽  
Vladimir F. Spirin
Keyword(s):  
Physical Activity ◽  
Functional Condition ◽  
Anthropometric Data ◽  
Agricultural Machine ◽  
Machine Operators ◽  
Health Disorders ◽  
Space Layout ◽  
Combine Harvesters ◽  
High Degree ◽  
The Impact

Introduction. T e leading place in the structure of occupational morbidity of agricultural machine operators is occupied by vertebroneurological diseases, the development of which can be associated with the impact of ergonomic factors of labor activity. T e aim of the study is to assess the ergonomic factors of working conditions on mobile agricultural machinery and to identify their impact on the formation of health disorders of agricultural machine operators. Materials and methods. Complex physiological and ergonomic researches at operation of tractors and combine harvesters of old samples of domestic production including an assessment of the organization of workplaces on compliance to requirements of ergonomics and anthropometric data of workers, temporary, statodynamic, biomechanical characteristics of working poses and movements, a functional condition of machine operators (130 people aged 20–45 years with professional experience of work not less than three years) in dynamics of a work shift are carried out. Anthropometric studies were conducted among male machine operators (663 people) aged 18–59 years and with experience in the profession for more than three years. Results. The discrepancy between the size and space-layout parameters of workplaces ergonomic requirements and anthropometric data of machine operators, causing the formation of uncomfortable working positions, increasing physical activity and the severity of the labor process. A high degree of correlation between changes in the parameters of the neuromuscular system and the severity of the discrepancy between the ergonomic parameters of anthropometric characteristics of machine operators (r=0,7). T e results of the research allowed to determine the priority measures for the prevention of vertebroneurological diseases in agricultural machine operators. Conclusions. T e organization of workplaces on domestic tractors and combine harvesters of old samples does not meet the ergonomic requirements and anthropometric data of machine operators, which is the reason for the formation of an uncomfortable working posture, increased statodynamic physical activity, early development of fatigue and fatigue in the process, which can cause the development of pathological conditions of the spine and ligamentous apparatus. Ergonomic improvement of workplaces is one of the priority measures to preserve the health of agricultural machine operators.

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