Does energy conversion contribute to economic development in emerging and growth leading economies (EAGLE's): evidence from panel ARDL approach.

Energy is an essential indication of productivity, usage, and nation-building in the development context. However, energy diversity that emphasizes renewables is still vital for economic development in emerging nations. This study examines the impact of renewable energy on economic development in emerging and growth-leading economies (EAGLE's) from 1980 to 2019. The econometric procedure used in this study is pooled mean group regression/Panel ARDL approach. The study's results support the growth-conservation theory and demonstrate that wealth creation is not dependent entirely on fossil fuels and that other energy sources may also be used. There is a positive association between renewable energy production and consumption and economic development in EAGLE countries. For the overall sample selected, the association between the long run and short is positive and significant, whereas individual analysis for each country provided mixed results. In the short run, the association between renewable energy consumption and economic development for Bangladesh, India, Indonesia, Mexico, and Philippines is negative. While in production, most countries showed positive and significant results except Brazil, Indonesia, Mexico, and Russia. The result of this study will help policy makers from the selected countries towards the use of renewable energy production and consumption, its importance and contribution to the economic development of these countries. However, some countries showed a negative relationship particularly Russian economy is rich in natural resources (oil, natural gas). While the remaining countries that showed negative relationship have number of problems associated with renewable energy consumption and production. This study refers the attention of policy makers from developing countries to consider the potential impact of renewable energy for the economic development. Energy transition can also contribute to the environmental protection and the reduction of greenhouse gases.

Volatility correlation structure, dynamic network and portfolio implications of Chinese stock market.

This study combines complex networks and sliding window technology to construct a static and dynamic network of volatility of the stocks in CSI 300 index using the COVID-19 epidemic as an example to analyze the impact of public health emergencies on the correlation structure of stock volatility, as an extended application to mine low-risk stock portfolios that are more resistant to risks under the "mean-variance" framework. Research shows three implications. (i) During the outbreak period, the density of the stock market volatility network was significantly higher than before and after the outbreak, and the network structure was more intense during the outbreak period. The leading industries are the manufacturing and financial industries, and the source of market risk transmission comes from the key nodes of the two industries. (ii) The dynamic network shows that under the impact of the epidemic, the correlation structure of stock market volatility has undergone abrupt changes and the overall market risk is time-changing, which indicates that the sudden impact of degeneration breaks the original structure and triggers new information connections in the stock market. (iii) The degree of stock centrality affects investment portfolio returns, which means that core stock portfolios with greater network centrality during the relatively stable market period and the upward period perform better, and the peripheral stock portfolio has an advantage in the period when the market fluctuates due to sudden external shocks. Interestingly, peripheral stock portfolios with lower centrality are more resistant to risks under sudden shocks. The results of this paper can provide important enlightenment for stock market supervision and investment portfolio risk management.

The comparison of economic impacts of COVID-19 between China and the United States.

The outbreak of the COVID-19 in 2020 has a severe impact on all countries. This paper first studies the impact of the epidemic on the macro-economy in China, which is one of the countries with early epidemic situation, in the rapid development stage of the epidemic situation, and the specific performance in macro-economy aspects. On this basis, study the development trend and macroeconomic performance of the United States as one of the most serious countries, and the relationship between the epidemic development and macro-economy in the United States. As for the differences in epidemic control measures between China and the US, China's indicators are significant in terms of sentiment factors, but the impact of COVID-19 on the sentiment factors in the US is different. The Chinese government has not adopted unlimited easing and maintained consistent policies. At present, the economic impact of COVID-19 on the US is far greater than that of China.

DECAF score as a mortality predictor for acute exacerbation of chronic obstructive pulmonary disease: a systematic review and meta-analysis.

OBJECTIVES: This study was conducted to assess the association between the Dyspnea, Eosinopenia, Consolidation, Acidemia and Atrial Fibrillation (DECAF) scores and the prognosis of patients with acute exacerbation of chronic obstructive pulmonary disease (AECOPD), to evaluate the specific predictive and prognostic value of DECAF scores and to explore the effectiveness of different cut-off values in risk stratification of patients with AECOPD. DESIGN: Systematic review and meta-analysis. PARTICIPANTS: Adult patients diagnosed with AECOPD (over 18 years of age). PRIMARY AND SECONDARY OUTCOME MEASURES: Electronic databases, including the Cochrane Library, PubMed, the Embase and the WOS, and the reference lists in related articles were searched for studies published up to September 2019. The identified studies reported the prognostic value of DECAF scores in patients with AECOPD. RESULTS: Seventeen studies involving 8329 participants were included in the study. Quantitative analysis demonstrated that elevated DECAF scores were associated with high mortality risk (weighted mean difference=1.87; 95% CI 1.19 to 2.56). In the accuracy analysis, DECAF scores showed good prognostic accuracy for both in-hospital and 30-day mortality (area under the receiver operating characteristic curve: 0.83 (0.79-0.86) and 0.79 (0.76-0.83), respectively). When the prognostic value was compared with that of other scoring systems, DECAF scores showed better prognostic accuracy and stable clinical values than the modified DECAF; COPD and Asthma Physiology Score; BUN, Altered mental status, Pulse and age >65; Confusion, Urea, Respiratory Rate, Blood pressure and age >65; or Acute Physiology and Chronic Health Evaluation II scores. CONCLUSION: The DECAF score is an effective and feasible predictor for short-term mortality. As a specific and easily scored predictor for patients with AECOPD, DECAF score is superior to other prognostic scores. The DECAF score can correctly identify most patients with AECOPD as low risk, and with the increase of cut-off value, the risk stratification of DECAF score in high-risk population increases significantly.

Prevalence of chronic obstructive pulmonary disease at high altitude: a systematic review and meta-analysis.

BACKGROUND AND OBJECTIVE: Recently, several studies have investigated the prevalence of chronic obstructive pulmonary disease (COPD) at high altitude (>1,500 m). However, much remains to be understood about the correlation between altitude and COPD. We aimed to summarize the prevalence of COPD at high-altitudes and find out if altitude could be a risk factor for COPD. METHODS: We searched PubMed/Medline, Cochrane Library, Web of Science, SCOPUS, OVID, Chinese Biomedical Literature Database (CBM) and Embase databases from inception to April 30th, 2019, with no language restriction. We used STATA 14.0 to analyze the extracted data. A random-effect model was used to calculate the combined OR and 95% CI. Heterogeneity was assessed by the I 2 statistic versus P-value. We performed a subgroup analysis to analyze possible sources of heterogeneity. The Egger's test and the Begg's test were used to assess any publication bias. RESULTS: We retrieved 4,574 studies from seven databases and finally included 10 studies (54,578 participants). Males ranged from 18.8% to 49.3% and the population who smoked ranged from 3.3% to 53.3%. The overall prevalence of COPD at high-altitude was 10.0% (95% CI [0.08-0.12], P < 0.001). In a subgroup analysis, based on different regions, the results showed that the prevalence in Asia was higher than that in Europe and America. Seven studies compared the relationship between the prevalence of COPD at high-altitudes and the lowlands. The results showed that altitude was not an independent risk factor for the prevalence of COPD (ORadj = 1.18, 95% CI [0.85-1.62], P = 0.321). There was no publication bias among the studies. CONCLUSIONS: Our study found a higher prevalence of COPD at high-altitudes than those from average data. However, altitude was not found to be an independent risk factor for developing COPD (PROSPERO Identifier: CRD42019135012).