scholarly journals Role of Weather Factors in COVID-19 Death Growth Rates in Tropical Climate: A Data-Driven Study Focused on Brazil Manuscript

2020 ◽  
Author(s):  
Rahul Kalippurayil Moozhipurath
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Cloud Cover ◽  
Time Varying ◽  
Ozone Pollution ◽  
Weather Factors ◽  
Tropical Country ◽  
Tropical Countries ◽  
Percentage Points

AbstractBackgroundBrazil reported 123,780 deaths across 27 administrative regions, making it the second-worst affected country after the US in terms of COVID-19 deaths as of 3 September 2020. Understanding the role of weather factors in COVID-19 in Brazil is helpful in the long-term mitigation strategy of COVID-19 in other tropical countries because Brazil experienced early large-scale outbreak among tropical countries. Recent COVID-19 studies indicate that relevant weather factors such as temperature, humidity, UV Index (UVI), precipitation, ozone, pollution and cloud cover may influence the spread of COVID-19. Yet, the magnitude and direction of those associations remain inconclusive. Furthermore, there is only limited research exploring the impact of these weather factors in a tropical country like Brazil. In this observational study, we outline the roles of 7 relevant weather factors including temperature, humidity, UVI, precipitation, ozone, pollution (visibility) and cloud cover in COVID-19 death growth rates in Brazil.MethodsWe use a log-linear fixed-effects model to a panel dataset of 27 administrative regions in Brazil across 182 days (n=3882) and analyze the role of relevant weather factors by using daily cumulative COVID-19 deaths in Brazil as the dependent variable. We carry out robustness checks using case-fatality-rate (CFR) as the dependent variable.FindingsWe control for all region-specific time-fixed factors as well as potentially confounding time-varying factors. We observe a significant negative association of COVID-19 daily deaths growth rate in Brazil with weather factors - UVI, temperature, ozone and cloud cover. Specifically, a unit increase in UVI, maximum temperature, and ozone level independently associate with 6.0 percentage points [p<0.001], 1.8 percentage points [p<0.01] and 0.3 percentage points [p<0. 1] decline in COVID-19 deaths growth rate. Further, a percentage point increase in cloud cover associates with a decline of 0.148 percentage points [p<0.05] in COVID-19 deaths growth rate. Surprisingly, contrary to other studies, we do not find evidence of any association between COVID-19 daily deaths growth rate and humidity, visibility and precipitation. We find our results to be consistent even when we use the CFR as the dependent variable.InterpretationWe find independent protective roles of UVI, temperature, ozone and cloud cover in mitigating COVID-19 deaths growth rate, even in a tropical country like Brazil. We observe these results to be consistent across various model specifications, especially for UVI and cloud cover, even after incorporating additional time-varying weather parameters such as dewpoint, pressure, wind speed and wind gust. These results could guide health-related policy decision making in Brazil as well as similar tropical countries.

scholarly journals Evidence of Protective Role of Ultraviolet-B (UVB) Radiation in Reducing COVID-19 Deaths Manuscript

2020 ◽  
Author(s):  
Rahul Kalippurayil Moozhipurath ◽  
Lennart Kraft ◽  
Bernd Skiera
Keyword(s):  
Vitamin D ◽  
Growth Rates ◽  
Protective Role ◽  
Negative Association ◽  
Ultraviolet B ◽  
Time Varying ◽  
Uvb Radiation ◽  
Daily Growth ◽  
Percentage Points

AbstractBackgroundResearch is ongoing to identify an effective way to prevent or treat COVID-19, but thus far these efforts have not yet identified a possible solution. Prior studies indicate the protective role of Ultraviolet-B (UVB) radiation in human health, mediated by vitamin D synthesis. In this study, we empirically outline a negative association of UVB radiation as measured by ultraviolet index (UVI) with the number of deaths attributed to COVID-19 (COVID-19 deaths).MethodsWe carry out an observational study, applying a fixed-effect log-linear regression model to a panel dataset of 64 countries over a period of 78 days (n=4992). We use the cumulative number of COVID-19 deaths and case-fatality rate (CFR) as the main dependent variables to test our hypothesis and isolate UVI effect from potential confounding factors such as underlying time trends, country-specific time-constant and time-varying factors such as weather.FindingsAfter controlling for time-constant and time-varying factors, we find that a permanent unit increase in UVI is associated with a 2.2 percentage points decline in daily growth rates of cumulative COVID-19 deaths [p < 0.01] as well as a 1.9 percentage points decline in the daily growth rates of CFR [p < 0.05]. These results represent a significant percentage reduction in terms of the daily growth rates of cumulative COVID-19 deaths (−22.92%) and CFR (−73.08%). Our results are consistent across different model specifications.InterpretationWe find a significant negative association between UVI and COVID-19 deaths, indicating evidence of the protective role of UVB in mitigating COVID-19 deaths. If confirmed via clinical studies, then the possibility of mitigating COVID-19 deaths via sensible sunlight exposure or vitamin D intervention will be very attractive because it is cost-effective and widely available.

scholarly journals Does Lockdown Decrease the Protective Role of Ultraviolet-B (UVB) Radiation in Reducing COVID-19 Deaths?

2020 ◽  
Author(s):  
Rahul Kalippurayil Moozhipurath ◽  
Lennart Kraft
Keyword(s):  
Time Constant ◽  
Growth Rates ◽  
Protective Role ◽  
Ultraviolet B ◽  
Time Varying ◽  
Uvb Radiation ◽  
Percentage Points ◽  
Uvb Exposure ◽  
Country Specific

AbstractBackgroundNations are imposing unprecedented measures at large-scale to contain the spread of COVID-19 pandemic. Recent studies indicate that measures such as lockdowns may have slowed down the growth of COVID-19. However, in addition to substantial economic and social costs, these measures also limit the exposure to Ultraviolet-B radiation (UVB). Emerging observational evidence indicate the protective role of UVB and vitamin D in reducing the severity and mortality of COVID-19 deaths. In this observational study, we empirically outline the independent protective roles of lockdown and UVB exposure as measured by ultraviolet index (UVI), whilst also examining whether the severity of lockdown is associated with a reduction in the protective role.MethodsWe apply a log-linear fixed-effects model to a panel dataset of 162 countries over a period of 108 days (n=6049). We use the cumulative number of COVID-19 deaths as the dependent variable and isolate the mitigating influence of lockdown severity on the association between UVI and growth-rates of COVID-19 deaths from time-constant country-specific and time-varying country-specific potentially confounding factors.FindingsAfter controlling for time-constant and time-varying factors, we find that a unit increase in UVI and lockdown severity are independently associated with 17% [-1.8 percentage points] and 77% [-7.9 percentage points] decline in COVID-19 deaths growth rate, indicating their respective protective roles. However, the widely utilized and least severe lockdown (recommendation to not leave the house) already fully mitigates the protective role of UVI by 95% [1.8 percentage points] indicating its downside.InterpretationWe find that lockdown severity and UVI are independently associated with a slowdown in the daily growth rates of cumulative COVID-19 deaths. However, we find consistent evidence that increase in lockdown severity is associated with a significant reduction in the protective role of UVI in reducing COVID-19 deaths. Our results suggest that lockdowns in conjunction with adequate exposure to UVB radiation might have provided even more substantial health benefits, than lockdowns alone. For example, we estimate that there would be 21% fewer deaths on average with sufficient UVB exposure while people were recommended not to leave their house. Therefore, our study outlines the importance of considering UVB exposure, especially while implementing lockdowns and may support policy decision making in countries imposing such measures.

scholarly journals Role of carbon allocation efficiency in the temperature dependence of autotroph growth rates

2018 ◽  
Vol 115 (31) ◽  
pp. E7361-E7368 ◽  
Author(s):  
Bernardo García-Carreras ◽  
Sofía Sal ◽  
Daniel Padfield ◽  
Dimitrios-Georgios Kontopoulos ◽  
Elvire Bestion ◽  
...  
Keyword(s):  
Growth Rate ◽  
Temperature Dependence ◽  
Growth Rates ◽  
Carbon Allocation ◽  
Thermal Sensitivity ◽  
Potential Growth ◽  
Allocation Efficiency ◽  
Population Growth Rates ◽  
Performance Curves

Relating the temperature dependence of photosynthetic biomass production to underlying metabolic rates in autotrophs is crucial for predicting the effects of climatic temperature fluctuations on the carbon balance of ecosystems. We present a mathematical model that links thermal performance curves (TPCs) of photosynthesis, respiration, and carbon allocation efficiency to the exponential growth rate of a population of photosynthetic autotroph cells. Using experiments with the green alga, Chlorella vulgaris, we apply the model to show that the temperature dependence of carbon allocation efficiency is key to understanding responses of growth rates to warming at both ecological and longer-term evolutionary timescales. Finally, we assemble a dataset of multiple terrestrial and aquatic autotroph species to show that the effects of temperature-dependent carbon allocation efficiency on potential growth rate TPCs are expected to be consistent across taxa. In particular, both the thermal sensitivity and the optimal temperature of growth rates are expected to change significantly due to temperature dependence of carbon allocation efficiency alone. Our study provides a foundation for understanding how the temperature dependence of carbon allocation determines how population growth rates respond to temperature.

THE ROLE OF TRANSITORY AND PERSISTENT SHOCKS IN THE CONSUMPTION CORRELATION AND INTERNATIONAL COMOVEMENT PUZZLES

2013 ◽  
Vol 18 (6) ◽  
pp. 1234-1270 ◽  
Author(s):  
Tatsuma Wada
Keyword(s):  
Growth Rate ◽  
Learning Process ◽  
Productivity Growth ◽  
Growth Rates ◽  
Imperfect Information ◽  
Transitory Shocks ◽  
Technological Growth ◽  
No Consumption

We study a two-country model with changes in the technological growth rate. Such changes are attributed to transitory and persistent shocks in the growth rate of technology. Cases are considered in which agents in two countries do not have enough information to distinguish between the two types of shocks; gradually, however, the persistence of the shock is recognized through the learning process. Utilizing a set of parameters obtained from U.S. and European productivity growth rates, it is then shown that (i) when persistent shocks affect the two countries identically, there is no consumption-correlation puzzle, and the international comovement puzzle becomes imperceptible; and (ii) even when persistent shocks affect the two countries differently, imperfect information plays an important role in explaining both the consumption-correlation puzzle and the international comovement puzzle (provided transitory shocks are strongly internationally correlated and are relatively larger than persistent shocks).

Relationship between some Staphylococcus aureus pathogenic factors and growth rates and somatic cell counts

2005 ◽  
Vol 72 (2) ◽  
pp. 203-208 ◽  
Author(s):  
Alfonso Zecconi ◽  
Enrica Binda ◽  
Vitaliano Borromeo ◽  
Renata Piccinini
Keyword(s):  
Growth Rate ◽  
Inflammatory Response ◽  
Growth Rates ◽  
Protein Gene ◽  
The Other ◽  
Staph Aureus ◽  
Pathogenic Factors ◽  
Binding Protein Gene ◽  
The One

Staphylococcus aureus isolates produce several pathogenic factors. The combination of these products influences the pathogenic role of different isolates, but their specific effects are well known in the pathogenesis of udder infections. This study focused on the association of polymorphism of the coagulase gene, protein A gene, collagen-binding protein gene, and of fibrinogen-binding protein gene on somatic cell count (SCC) and on Staph. aureus growth rate. Fifty Staph. aureus isolates from 13 dairy cow herds, located in seven different provinces, were considered. The results showed a low frequency of cna gene, similar to the one observed in human isolates. Meanwhile, the high frequency of efb gene indirectly confirmed the role of this factor in bacterial pathogenesis, being associated with adhesion to epithelia. The association of these two single genes with SCC and growth rate showed to be not significant. The polymorphism of spa gene was confirmed to be significantly associated with inflammatory response and growth rate, albeit with a pattern different from the one suggested for human isolates. Sorting of isolates based on the clusters obtained by combining polymorphisms of spa and coa genes and the presence of cna and efb genes, showed that a single cluster (cluster V) was prevalent in the different herds and provinces, while the other six clusters identified were widely spread among the remaining 60% of the isolates. Results showed that clusters VI and VII had significantly higher growth rates at 3, 4, and 6 h in comparison with the other clusters. Meanwhile, quarters infected with these strains showed significantly lower SCC levels. The frequency of isolates from cluster V, suggested that they should possess pathogenic factors increasing their invasiveness, even if in the presence of a stronger inflammatory response. These results indirectly confirm previous findings on the different interactions between isolates and the udder immune system. They also suggest that isolates with higher growth rates and inducing a lower inflammatory response have better chances to spread among the herd. The relatively simple genomic method proposed in this study could be applied by an increasing number of diagnostic laboratories and could be useful in studying the epidemiology of Staph. aureus intramammary infections in dairy herds when collecting data from the field.

scholarly journals Evidence of Protective Role of Ultraviolet-B (UVB) Radiation in Reducing COVID-19 Deaths 

2020 ◽  
Author(s):  
Rahul Kalippurayil Moozhipurath ◽  
Lennart Kraft ◽  
Bernd Skiera
Keyword(s):  
Vitamin D ◽  
Growth Rates ◽  
Protective Role ◽  
Negative Association ◽  
Ultraviolet B ◽  
Cumulative Number ◽  
Uvb Radiation ◽  
Daily Growth ◽  
Percentage Points

Abstract Background. Prior studies indicate the protective role of Ultraviolet-B (UVB) radiation in human health, mediated by vitamin D synthesis. In this observational study, we empirically outline a negative association of UVB radiation as measured by ultraviolet index (UVI) with the number of COVID-19 deaths.Methods. We apply a fixed-effect log-linear regression model to a panel dataset of 152 countries over 108 days (n=6524). We use the cumulative number of COVID-19 deaths and case-fatality rate (CFR) as the main dependent variables and isolate UVI effect from potential confounding factors.Findings. After controlling for time-constant and time-varying factors, we find that a permanent unit increase in UVI is associated with a 1.2 percentage points decline in daily growth rates of cumulative COVID-19 deaths [p < 0.01] and a 1.0 percentage points decline in the CFR daily growth rate [p < 0.05]. These results represent a significant percentage reduction in terms of daily growth rates of cumulative COVID-19 deaths (-11.88%) and CFR (-38.46%).Interpretation. We find a significant negative association between UVI and COVID-19 deaths, indicating evidence of the protective role of UVB in mitigating COVID-19 deaths. If confirmed via clinical studies, then the possibility of mitigating COVID-19 deaths via sensible sunlight exposure or vitamin D intervention will be very attractive.

scholarly journals Estimating Time-Varying Long-Run Growth Rate of Russian GDP in the ARX Model with Oil Prices

2020 ◽  
Vol 15 (1) ◽  
pp. 40-63 ◽  
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Oil Prices ◽  
Likelihood Method ◽  
Time Varying ◽  
Arx Model ◽  
Long Run ◽  
Unobserved Components Model ◽  
The Impact ◽  
Trend Growth

The paper estimates the path of trend growth rates for Russian GDP based on an autoregressive model with exogenous variables and with a time-varying parameter of trend growth, which, by assumption, is described by a random walk process. In conditions of a high dependence of the Russian economy on commodity exports, terms of trade are used as a control exogenous variable for GDP dynamics. For the purpose of econometric estimation, the ARX model is presented as an unobserved components model and estimated using the maximum likelihood method with the Kalman filter applied. It is shown that in the first half of the 2000s the trend growth rate was at 4%, which can be interpreted as recovery growth after a transformational recession. The higher growth rates actually achieved during this period are explained by the intensive growth of world oil prices. Later, the potential for recovery growth was exhausted, and after the crisis of 2008 the rates of trend growth were remaining at the level of 2% per year for a long period of time. However, following the 2014 crisis, trend growth rates began to decline steadily, and had reached about 1% per year by the beginning of 2019, which can be interpreted as the impact of sanctions and geopolitical uncertainty on the economic development of the Russian Federation. The results of an econometric analysis of the model on household consumption and investment data also suggest that the trend growth rate is approximately 1% per year at present.

scholarly journals Evidence of protective role of Ultraviolet-B (UVB) radiation in reducing COVID-19 deaths

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Rahul Kalippurayil Moozhipurath ◽  
Lennart Kraft ◽  
Bernd Skiera
Keyword(s):  
Vitamin D ◽  
Growth Rates ◽  
Protective Role ◽  
Negative Association ◽  
Ultraviolet B ◽  
Cumulative Number ◽  
Uvb Radiation ◽  
Daily Growth ◽  
Percentage Points

Abstract Prior studies indicate the protective role of Ultraviolet-B (UVB) radiation in human health, mediated by vitamin D synthesis. In this observational study, we empirically outline a negative association of UVB radiation as measured by ultraviolet index (UVI) with the number of COVID-19 deaths. We apply a fixed-effect log-linear regression model to a panel dataset of 152 countries over 108 days (n = 6524). We use the cumulative number of COVID-19 deaths and case-fatality rate (CFR) as the main dependent variables and isolate the UVI effect from potential confounding factors. After controlling for time-constant and time-varying factors, we find that a permanent unit increase in UVI is associated with a 1.2 percentage points decline in daily growth rates of cumulative COVID-19 deaths [p < 0.01] and a 1.0 percentage points decline in the CFR daily growth rate [p < 0.05]. These results represent a significant percentage reduction in terms of daily growth rates of cumulative COVID-19 deaths (− 12%) and CFR (− 38%). We find a significant negative association between UVI and COVID-19 deaths, indicating evidence of the protective role of UVB in mitigating COVID-19 deaths. If confirmed via clinical studies, then the possibility of mitigating COVID-19 deaths via sensible sunlight exposure or vitamin D intervention would be very attractive.

scholarly journals Population growth rates: issues and an application

2002 ◽  
Vol 357 (1425) ◽  
pp. 1307-1319 ◽  
Author(s):  
H. Charles J. Godfray ◽  
Mark Rees
Keyword(s):  
Growth Rate ◽  
Population Dynamics ◽  
Population Growth ◽  
Growth Rates ◽  
Population Growth Rate ◽  
Population Change ◽  
Evolutionarily Stable Strategy ◽  
Model Systems ◽  
Population Growth Rates

Current issues in population dynamics are discussed in the context of The Royal Society Discussion Meeting 'Population growth rate: determining factors and role in population regulation'. In particular, different views on the centrality of population growth rates to the study of population dynamics and the role of experiments and theory are explored. Major themes emerging include the role of modern statistical techniques in bringing together experimental and theoretical studies, the importance of long-term experimentation and the need for ecology to have model systems, and the value of population growth rate as a means of understanding and predicting population change. The last point is illustrated by the application of a recently introduced technique, integral projection modelling, to study the population growth rate of a monocarpic perennial plant, its elasticities to different life-history components and the evolution of an evolutionarily stable strategy size at flowering.

Technical Progress and the Natural Rate in Models of the UK Economy

1998 ◽  
Vol 164 ◽  
pp. 80-89 ◽  
Author(s):  
Keith B. Church ◽  
Peter R. Mitchell ◽  
Joanne E. Sault ◽  
Kenneth F. Wallis
Keyword(s):  
Growth Rate ◽  
Technical Progress ◽  
Real Wages ◽  
Natural Rate ◽  
Simulation Experiments ◽  
Neoclassical Growth Model ◽  
Percentage Points ◽  
The Uk ◽  
Neoclassical Growth

This article analyses the role of technical progress in three models of the UK economy. In the standard neoclassical growth model, the growth of the economy is dictated by the growth rate of technical progress plus that of the population. Our two simulation experiments, increasing the level of technical progress by 1 per cent and the growth rate by 0.1 percentage points, suggest that technological progress plays the same role in these large macroeconometric models. In both cases the result is higher output and real wages. However adjustment following the shocks is protracted, giving substantial technological unemployment which in several instances is permanent.

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