Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 4 de 4
Filter
1.
Sci Rep ; 11(1): 21413, 2021 11 01.
Article in English | MEDLINE | ID: covidwho-1493222

ABSTRACT

In this study, we proposed a new data-driven hybrid technique by integrating an ensemble empirical mode decomposition (EEMD), an autoregressive integrated moving average (ARIMA), with a nonlinear autoregressive artificial neural network (NARANN), called the EEMD-ARIMA-NARANN model, to perform time series modeling and forecasting based on the COVID-19 prevalence and mortality data from 28 February 2020 to 27 June 2020 in South Africa and Nigeria. By comparing the accuracy level of forecasting measurements with the basic ARIMA and NARANN models, it was shown that this novel data-driven hybrid model did a better job of capturing the dynamic changing trends of the target data than the others used in this work. Our proposed mixture technique can be deemed as a helpful policy-supportive tool to plan and provide medical supplies effectively. The overall confirmed cases and deaths were estimated to reach around 176,570 [95% uncertainty level (UL) 173,607 to 178,476] and 3454 (95% UL 3384 to 3487), respectively, in South Africa, along with 32,136 (95% UL 31,568 to 32,641) and 788 (95% UL 775 to 804) in Nigeria on 12 July 2020 using this data-driven EEMD-ARIMA-NARANN hybrid technique. The contributions of this study include three aspects. First, the proposed hybrid model can better capture the dynamic dependency characteristics compared with the individual models. Second, this new data-driven hybrid model is constructed in a more reasonable way relative to the traditional mixture model. Third, this proposed model may be generalized to estimate the epidemic patterns of COVID-19 in other regions.


Subject(s)
COVID-19/epidemiology , COVID-19/mortality , Models, Statistical , Neural Networks, Computer , Pandemics/prevention & control , SARS-CoV-2 , COVID-19/transmission , COVID-19/virology , Data Accuracy , Forecasting/methods , Humans , Nigeria/epidemiology , Prevalence , South Africa/epidemiology , Uncertainty
2.
Epidemiol Infect ; 148: e236, 2020 10 05.
Article in English | MEDLINE | ID: covidwho-834839

ABSTRACT

Forecasting the epidemics of the diseases is very valuable in planning and supplying resources effectively. This study aims to estimate the epidemiological trends of the coronavirus disease 2019 (COVID-19) prevalence and mortality using the advanced α-Sutte Indicator, and its prediction accuracy level was compared with the most frequently adopted autoregressive integrated moving average (ARIMA) method. Time-series analysis was performed based on the total confirmed cases and deaths of COVID-19 in the world, Brazil, Peru, Canada and Chile between 27 February 2020 and 30 June 2020. By comparing the prediction reliability indices, including the root mean square error, mean absolute error, mean error rate, mean absolute percentage error and root mean square percentage error, the α-Sutte Indicator was found to produce lower forecasting error rates than the ARIMA model in all data apart from the prevalence testing set globally. The α-Sutte Indicator can be recommended as a useful tool to nowcast and forecast the COVID-19 prevalence and mortality of these regions except for the prevalence around the globe in the near future, which will help policymakers to plan and prepare health resources effectively. Also, the findings of our study may have managerial implications for the outbreak in other countries.


Subject(s)
Betacoronavirus , Coronavirus Infections/epidemiology , Pneumonia, Viral/epidemiology , COVID-19 , Coronavirus Infections/mortality , Forecasting , Humans , Models, Statistical , Pandemics , Pneumonia, Viral/mortality , Prevalence , Reproducibility of Results , SARS-CoV-2
3.
Infect Drug Resist ; 13: 3335-3350, 2020.
Article in English | MEDLINE | ID: covidwho-818732

ABSTRACT

OBJECTIVE: The aim of this study is to apply the advanced error-trend-seasonal (ETS) framework to forecast the prevalence and mortality series of COVID-19 in the USA, the UK, Russia, and India, and the predictive performance of the ETS framework was compared with the most frequently used autoregressive integrated moving average (ARIMA) model. MATERIALS AND METHODS: The prevalence and mortality data of COVID-19 in the USA, the UK, Russia, and India between 20 February 2020 and 15 May 2020 were extracted from the WHO website. Then, the data subsamples between 20 February 2020 and 3 May 2020 were treated as the training horizon, and the others were used as the testing horizon to construct the ARIMA models and the ETS models. RESULTS: Based on the model evaluation criteria, the ARIMA (0,2,1) and ETS (M,MD,N), sparse coefficient ARIMA (0,2,(1,6)) and ETS (A,AD,M), ARIMA (1,1,1) and ETS (A,MD,A), together with ARIMA (2,2,1) and ETS (A,M,A) specifications were identified as the preferred ARIMA and ETS models for the prevalence data in the USA, the UK, Russia, and India, respectively; the ARIMA (0,2,1) and ETS (M,A,M), ARIMA (0,2,1) and ETS (M,A,N), ARIMA (0,2,1) and ETS (A,A,N), coupled with ARIMA (0,2,2) and ETS (M,M,N) specifications were selected as the optimal ARIMA and ETS models for the mortality data in these four countries, respectively. Among these best-fitting models, the ETS models produced smaller forecasting error rates than the ARIMA models in all the datasets. CONCLUSION: The ETS framework can be used to nowcast and forecast the long-term temporal trends of the COVID-19 prevalence and mortality in the USA, the UK, Russia, and India, and which provides a notable performance improvement over the most frequently used ARIMA model. Our findings can aid governments as a reference to prepare for and respond to the COVID-19 pandemic both in restricting the transmission of the disease and in lowering the disease-related deaths in the upcoming days.

4.
J Hazard Mater ; 396: 122747, 2020 09 05.
Article in English | MEDLINE | ID: covidwho-72153

ABSTRACT

Exposure to PM2.5 has been linked to respiratory disorders, yet knowledge of the molecular mechanism is limited. Here, PM2.5 was monitored and collected in central China, and its cytotoxicity mechanism on human bronchial epithelial cells (BEAS-2B) was investigated. With the average concentration of 109 ±â€¯69 µg/m3, PM2.5 was rich in heavy metals and organic pollutants. After exposure to PM2.5, the viability of BEAS-2B cells decreased, where 510 dysregulated genes were predicted to induce necroptosis via inhibiting ATP synthesis through the oxidative phosphorylation signaling pathway. Cellular experiments demonstrated that the content of ATP was downregulated, while the expression of RIP3, a necroptosis indicator, was upregulated. Besides, four enzymes in charge of ATP synthesis were downregulated, including ATP5F, NDUF, COX7A, and UQCR, while two genes of RELA and CAPN1 responsible for necroptosis were upregulated. Furthermore, N-acetylcysteine was applied as an enhancer for ATP synthesis, which reversed the downregulation of ATP5F, NDUF, and COX7A, and consequently alleviated the elevation of RELA, CAPN1, and RIP3. In conclusion, PM2.5 exposure downregulates ATP5F, NDUF, COX7A, and UQCR, and that inhibits ATP synthesis via the oxidative phosphorylation signaling pathway, which subsequently upregulates RELA and CAPN1 and ultimately leads to necroptosis of BEAS-2B cells.


Subject(s)
Air Pollutants , Particulate Matter , Air Pollutants/analysis , Air Pollutants/toxicity , China , Epithelial Cells , Humans , Particulate Matter/analysis , Particulate Matter/toxicity , Signal Transduction
SELECTION OF CITATIONS
SEARCH DETAIL