This paper examines the potential determinants of the exchange rate in Yemen. Different econometric tests were applied to examine the impact of the exchange rate on the inflation rate, the current account balance, GDP growth, and interest rate from 1998 to 2020. Findings show variables are stationary at first difference I(1). Johansen's cointegration test approved the existence of the long-term relationship. According to the VECM test, the variables share a long-run relationship. There is also a short-run association of the exchange rate with inflation and interest rate. The Granger causality test implies that the exchange rate granger causes interest rate and inflation rate. Furthermore, diagnostic tests were performed to check the results' reliability, which shows the findings are consistent. Moreover, the study also suggests that these findings contribute to policymakers and government officials' understanding of the exchange rate fluctuation. It will also show the significant impact of the exchange rate on these variables in Yemen and other developing countries with a similar economic system. The research also provides suggestions to promote development sustainability in Yemen.

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This study examines the impact of COVID-19 cases on GDP growth and Unemployment in developed countries represented by Germany, France, and Spain and developing countries represented by Mexico, Uruguay, Brazil, Turkey, and China. Various statistical tests were employed; ADF-Fisher Chi-Square for stationarity, Pedroni Cointegration test, Hausemn test, and panel granger causality test. The empirical results suggest that data from developed and developing countries are stationary at I (1). The Pedroni cointegration test revealed no long-run relationship between the dependent variables (Covid cases) and independent variables represented by GDP growth and Unemployment. The Hausman test showed that the fixed effect model is suitable for this study. The fixed effect model's estimation suggests that there is a positive and significant association between COVID-19 with unemployment rate and GDP growth in industrialized countries. However, in developing countries, the rise in COVID cases causes a decrease in GDP growth and Unemployment. The study contribution is critically significant for policymakers and scientists to set a plan for the comprehensive economic recovery for the world after the pandemic.

With the progress of social technology and the economy and the development of globalization, supply chain management has become the most important means to help enterprises obtain competitive advantages. This paper takes the impact of supply chain integration on enterprise competitive advantage as the research object. Therefore, the author combs the research literature of supply chain integration and enterprise competitive advantage and refers to other scholars' composition mechanisms of enterprise competitive advantage. At the same time, the author conducted research on the service industry and constructs the supply chain integration enterprise competitive advantage model, based on the literature review and interview analysis results. The author puts forward a series of research hypotheses to test the correlation between the variables in the competitive advantage model. According to the research hypothesis and the characteristics of the service industry, the paper designs a questionnaire and carries on the research, uses statistical software to analyze the data of 133 valid samples, and verifies the feasibility of applying the model to the establishment of the service industry. The test results show that the competitive advantage model is valid for service industry. This study verifies the feasibility of applying the enterprise competitive advantage model to the service industry, which has certain reference value for enhancing the competitive advantage of the service industry.