Objective:To study the number of leptospirosis cases in relations to the seasonal pattern,and its association with climate factors.Methods:Time series analysis was used to study the time variations in the number of le...Objective:To study the number of leptospirosis cases in relations to the seasonal pattern,and its association with climate factors.Methods:Time series analysis was used to study the time variations in the number of leptospirosis cases.The Autoregressive Integrated Moving Average (ARIMA) model was used in data curve fitting and predicting the next leptospirosis cases. Results:We found that the amount of rainfall was correlated to leptospirosis cases in both regions of interest,namely the northern and northeastern region of Thailand,while the temperature played a role in the northeastern region only.The use of multivariate ARIMA(ARIMAX) model showed that factoring in rainfall(with an 8 months lag) yields the best model for the northern region while the model,which factors in rainfall(with a 10 months kg) and temperature(with an 8 months lag) was the best for the northeaslern region.Conclusions:The models are able to show the trend in leptospirosis cases and closely fit the recorded data in both regions.The models can also be used to predict the next seasonal peak quite accurately.展开更多
Most biochemical processes in cells are usually modeled by reaction-diffusion （RD） equations. In these RD models, the diffusive process is assumed to be Gaussian. However, a growing number of studies have noted that...Most biochemical processes in cells are usually modeled by reaction-diffusion （RD） equations. In these RD models, the diffusive process is assumed to be Gaussian. However, a growing number of studies have noted that intracellular diffusion is anomalous at some or all times, which may result from a crowded environment and chemical kinetics. This work aims to computationally study the effects of chemical reactions on the diffusive dynamics of RD systems by using both stochastic and deterministic algorithms. Numerical method to estimate the mean-square displacement （MSD） from a deterministic algorithm is also investigated. Our computational results show that anomalous diffusion can be solely due to chemical reactions. The chemical reactions alone can cause anomalous sub-diffusion in the RD system at some or all times. The time-dependent anomalous diffusion exponent is found to depend on many parameters, including chemical reaction rates, reaction orders, and chemical concentrations.展开更多
In late December 2019,China declared that there were some citizens,in Wuhan,infected by an unknown pathogen[1].The number of infectious patients has increased rapidly,not only in China but also in other countries thro...In late December 2019,China declared that there were some citizens,in Wuhan,infected by an unknown pathogen[1].The number of infectious patients has increased rapidly,not only in China but also in other countries throughout the world.Thailand reported the first coronavirus disease 2019 (COVID-19) infected case,who was a traveler from Wuhan,China,on January 3rd,2020.Until March 10th,2020,the number of cases in Thailand was 53[2,3].All of these detected cases were travelers from high-risk countries and Thai people who were in very close contact with travelers.展开更多
Low-and middle-income countries faced significant challenges in accessing COVID-19 vaccines during the early stages of the pandemic.In this study,we utilized an agestructured modeling approach to examine the implicati...Low-and middle-income countries faced significant challenges in accessing COVID-19 vaccines during the early stages of the pandemic.In this study,we utilized an agestructured modeling approach to examine the implications of various vaccination strategies,vaccine prioritization,and vaccine rollout speeds in Thailand,an upper-middleincome country experiencing vaccine shortages during the early stages of the pandemic.The model directly compares the effectiveness of several vaccination strategies,including the heterologous vaccination where CoronaVac(CV)vaccine was administered as the first dose,followed by ChAdOx1 nCoV-19(AZ)vaccine as the second dose,under varying disease transmission dynamics.We found that the traditional AZ homologous vaccination was more effective than the CV homologous vaccination,regardless of disease transmission dynamics.However,combining CV and AZ vaccines via either parallel homologous or heterologous vaccinations was more effective than relying solely on AZ homologous vaccination.Additionally,prioritizing vaccination for the elderly aged 60 years and above was the most effective way to reduce mortality when community transmission is wellcontrolled.On the other hand,prioritizing workers aged 20e59 was most effective in lowering COVID-19 cases,irrespective of the transmission dynamics.Lastly,despite the vaccine prioritization strategy,rapid vaccine rollout speeds were crucial in reducing COVID-19 infections and deaths.These findings suggested that in low-and middle-income countries where early access to high-efficacy vaccines might be limited,obtaining any accessible vaccines as early as possible and using them in parallel with other higherefficacy vaccines might be a better strategy than waiting for and relying solely on higher-efficacy vaccines.展开更多
基金supported by Centre of Encellecne Mathentatics CHEThailand finanieally Sudaral Chadsuthi is supported by the Commission on Higher Education Thailand for its grant support under the Strategie Scholarships for Frintier Research Network for joint Ph.D.Programssupported by the National Science and Technology Development Agency (NSTDA) and Faculty of Science,Mahidol University
文摘Objective:To study the number of leptospirosis cases in relations to the seasonal pattern,and its association with climate factors.Methods:Time series analysis was used to study the time variations in the number of leptospirosis cases.The Autoregressive Integrated Moving Average (ARIMA) model was used in data curve fitting and predicting the next leptospirosis cases. Results:We found that the amount of rainfall was correlated to leptospirosis cases in both regions of interest,namely the northern and northeastern region of Thailand,while the temperature played a role in the northeastern region only.The use of multivariate ARIMA(ARIMAX) model showed that factoring in rainfall(with an 8 months lag) yields the best model for the northern region while the model,which factors in rainfall(with a 10 months kg) and temperature(with an 8 months lag) was the best for the northeaslern region.Conclusions:The models are able to show the trend in leptospirosis cases and closely fit the recorded data in both regions.The models can also be used to predict the next seasonal peak quite accurately.
基金supported by the Thailand Research Fund and Mahidol University(Grant No.TRG5880157),the Thailand Center of Excellence in Physics(ThEP),CHE,Thailand,and the Development Promotion of Science and Technology
文摘Most biochemical processes in cells are usually modeled by reaction-diffusion （RD） equations. In these RD models, the diffusive process is assumed to be Gaussian. However, a growing number of studies have noted that intracellular diffusion is anomalous at some or all times, which may result from a crowded environment and chemical kinetics. This work aims to computationally study the effects of chemical reactions on the diffusive dynamics of RD systems by using both stochastic and deterministic algorithms. Numerical method to estimate the mean-square displacement （MSD） from a deterministic algorithm is also investigated. Our computational results show that anomalous diffusion can be solely due to chemical reactions. The chemical reactions alone can cause anomalous sub-diffusion in the RD system at some or all times. The time-dependent anomalous diffusion exponent is found to depend on many parameters, including chemical reaction rates, reaction orders, and chemical concentrations.
基金financially supported by the National Science and Technology Development AgencyThailand(PO20008199)
文摘In late December 2019,China declared that there were some citizens,in Wuhan,infected by an unknown pathogen[1].The number of infectious patients has increased rapidly,not only in China but also in other countries throughout the world.Thailand reported the first coronavirus disease 2019 (COVID-19) infected case,who was a traveler from Wuhan,China,on January 3rd,2020.Until March 10th,2020,the number of cases in Thailand was 53[2,3].All of these detected cases were travelers from high-risk countries and Thai people who were in very close contact with travelers.
文摘Low-and middle-income countries faced significant challenges in accessing COVID-19 vaccines during the early stages of the pandemic.In this study,we utilized an agestructured modeling approach to examine the implications of various vaccination strategies,vaccine prioritization,and vaccine rollout speeds in Thailand,an upper-middleincome country experiencing vaccine shortages during the early stages of the pandemic.The model directly compares the effectiveness of several vaccination strategies,including the heterologous vaccination where CoronaVac(CV)vaccine was administered as the first dose,followed by ChAdOx1 nCoV-19(AZ)vaccine as the second dose,under varying disease transmission dynamics.We found that the traditional AZ homologous vaccination was more effective than the CV homologous vaccination,regardless of disease transmission dynamics.However,combining CV and AZ vaccines via either parallel homologous or heterologous vaccinations was more effective than relying solely on AZ homologous vaccination.Additionally,prioritizing vaccination for the elderly aged 60 years and above was the most effective way to reduce mortality when community transmission is wellcontrolled.On the other hand,prioritizing workers aged 20e59 was most effective in lowering COVID-19 cases,irrespective of the transmission dynamics.Lastly,despite the vaccine prioritization strategy,rapid vaccine rollout speeds were crucial in reducing COVID-19 infections and deaths.These findings suggested that in low-and middle-income countries where early access to high-efficacy vaccines might be limited,obtaining any accessible vaccines as early as possible and using them in parallel with other higherefficacy vaccines might be a better strategy than waiting for and relying solely on higher-efficacy vaccines.
