查看更多>>摘要：? 2022COVID-19 pandemic caused havoc around the globe in both economic and non-economic sectors. This paper, unlike previous studies, evaluates the role of COVID-19 on the volatility in natural resources. The volatility of natural resources commodity prices has been the center of discussion, especially during the pandemic. Unlike previous studies, this study aims to evaluate the role of the pandemic, i.e., Covid-19 and its possible impact on volatility in natural resources commodity prices for China. China has been the center of this epidemic disease and is considered one of the major economies affected by the Covid-19; therefore, it is better to conduct this study for China. This study uses data from January 2020 till September 2021 to capture the peak time of Covid-19. Moreover, this study employs the novel wavelet power spectrum and wavelet coherence approach to better capture volatility within commodity prices volatility and Covid-19 and evaluate the association between both variables. The empirical results reveal that only natural resources commodity prices are volatile and only short. While Covid-19 positive cases and Covid-19 deaths are not vulnerable during the study period. Moreover, the wavelet coherence conforms that both Covid-19 positive cases and Covid-19 deaths significantly cause volatility in natural resources commodity prices. Although, volatility is found at different periods; still, volatility is observed only in the short-run. The study also provides relevant policy implications to ensure a relevant and timely solution for the existing issue. Moreover, future research guidelines and the study's limitations are also provided.
查看更多>>摘要：? 2022 Elsevier LtdPreventing the risk of coal mine safety production is a long-term issue of national supervision. At present, scholars' research on coal mine safety regulation lacks practical application scenarios and internal-external collaborative governance. Therefore, this paper based on coal mine on-site regulatory mode and combined with the expectation theory constructs a multi-agent evolutionary game model of coal mining enterprises, regulators and front-line workers in the context of government regulation, and simulates how the government improves the efficiency of resident supervision mode. The simulation results are as follows. First, for coal mining enterprises, increase supervision and punishment, government support for safety production can promote the safety production of enterprises; Secondly, the government reduces the regulatory costs of regulators while improving the regulatory benefits, which will ease the regulatory pressure of regulators and urge them to strictly regulate. Increasing the rewards for effective regulation would increase the incentive for regulators to enforce the law rigorously. In addition, workers' supervision has a mutual restraint effect on the safety production of coal mine enterprises and the strict supervision of regulators. The government can promote the enthusiasm of workers' supervision by improving the reward for the success of workers' supervision, so as to avoid collusion between enterprises and regulators. Finally, when the regulators strictly perform their supervisory duties and the enterprises stabilize and produce safely, the supervision of workers will not play a role and the on-site regulatory mode will reach the best situation.
查看更多>>摘要：? 2022 Elsevier LtdSince the beginning of the 21st century, natural disasters and global economic shocks have affected economies in various aspects. This study investigates the causal relationship between the price volatility of natural resource commodity and global economic policy uncertainty in the US by using monthly data for the period of November 01, 2007–May 01, 2021. The wavelet power spectrum and wavelet coherence approaches are employed and the causal association is observed. In addition, the estimated results reveal that economic policy uncertainty and the price volatility of natural resource are more vulnerable than industrial production in the selected time span. Furthermore, the wavelet coherence illustrates a bidirectional causal association among global economic policy uncertainty, the price volatility of natural resource commodity and industrial production. However, a one-way causal association is observed running from industrial production to the price volatility of natural resource commodity. Moreover, the frequency domain causality validates the variables' short-run, medium-run, and long-run causal factors. The empirical findings offer several prominent policy implications which could be efficient from the long-run policy perspective.
查看更多>>摘要：? 2022There is a large body of work documenting the non-consensual effects of natural resources. Despite this extensive literature and the importance of innovation on economic outcomes, surprisingly little is known about the effect of natural resources on the research sector. This study proposes to fill this gap by examining the effect of natural resources on research and development expenditure. Using data from 82 developed and developing countries, we show that natural resources have on average a negative effect on research and development investment. We also find that natural resources are negatively associated with research and development expenditure in the public sector, higher education, and business sector. Distinguishing between different natural resources, we find that only point resources have a negative effect on the priorities given to research investments. Nevertheless, our results show that institutional quality and human capital are mechanisms to mitigate this trend.
查看更多>>摘要：? 2022 Elsevier LtdThis paper investigates whether the uncertainty-hedging aura of gold has faded away. The rolling window Granger causality tests are employed to detect the mutual relationship between the world uncertainty index (WUI) and gold price (GP). We find the positive influence that ripples from WUI towards GP, which indicates that gold keeps the uncertainty-hedging aura in times of economic and political disarray. GP may increase during certain high WUI periods to hedge risks of losses, and it also shows a declining trend during periods of low WUI. The results can be explained by the Intertemporal Capital Asset Pricing Model, which emphasizes that GP should lead to a positive response to WUI. In turn, the negative impact from GP to WUI suggests that the global political and economic situation can be predicted through the gold market. Therefore, investors are able to optimize the design of portfolios involving gold to hedge against the WUI. Furthermore, governments can analyze the global uncertainty trends through the path of GP, adjust policy formulations, counteract potential negative effects on the economy and promote the stable development of the world.
查看更多>>摘要：? 2022 Elsevier LtdThe significant increase in data availability and high-computing power and innovations in real-time monitoring systems enable the technological transformation of the mining industry. Artificial Intelligence (AI) and data-driven methods are becoming appealing solutions to tackle different challenges in mining operations where an increasingly larger body of research is being published. Strategic mine planning is one of the areas that can be greatly enhanced with the adaptation of AI techniques to make intelligent data-driven decisions. This paper presents a systematic literature review to identify research trends in this field both in the specific area of application and the AI technique used. Papers from popular scientific databases were compiled and categorized into three main identified research areas in this field: Production Planning and Scheduling, Equipment Management and Grade Control, and individual AI techniques were catalogued. The results indicated an exponential growth in the general number of publications, where the most consolidated techniques across all applications were Genetic Algorithms and Discrete Simulation.
查看更多>>摘要：? 2022 Elsevier LtdThe ongoing Russia-Ukraine war is obviously the most prominent war in Europe since the second world war, changing the dynamics of the oil and other prominent markets. As the oil market has been historically known to associate with other financial and commodity markets, it is important to see if oil connects differently with prominent financial assets during market turbulence caused by a war. Thus, we make the first attempt to examine how oil connects with prominent financial assets, namely bonds, bitcoin, U.S. dollar, gold, and stocks, using intra-day data, before and during the war. We find that connectedness is stronger during the war than before it. Oil becomes a net transmitter of spillovers during the war, unlike in the pre-war era when it is characterized as a net receiver of spillovers. Also, whereas the net directional pairwise results suggest heterogeneity regarding how oil connects individually with each of the remaining assets before the war, oil has a strong spillover effect on all of them during the war. However, the spillover effect is transitory, as it dies out over time. The findings are robust to intra-day data of different frequency, and have suitable implications for short-term investors, and further agendas for future research in relation to the impacts of the war are provided.
查看更多>>摘要：? 2022 Elsevier LtdNickel is one of six key metals needed for the global low-carbon energy transition. In recent years, with the rapid rise of the new energy vehicle industry, the imbalance between the global nickel resource supply and demand has become increasingly obvious. The intensification of the contradiction between supply and demand can easily lead to security concerns regarding the supply of resources, and supply shortages will endanger the healthy and orderly development of the whole industrial chain. Understanding the trade structure characteristics of the industrial chain and the correlation between adjacent layers can provide a certain reference for decision makers to prevent supply risks. Hence, based on the trade data related to the nickel industry chain, combined with complex network theory and the material flow analysis method, the multi-layer trade network of the nickel industry chain is constructed. Through the analysis of network characteristics, it is found that global competition for intermediate nickel products is fiercest. Under the influence of two driving factors, the core trading countries in each layer show two different export patterns. In addition, China's nickel industry chain development is the most vulnerable in the world. At the same time, the further down the nickel chain, the stronger the correlation between adjacent layers are, and the integrity of a national industrial chain can provide a certain reference for preventing supply risks. Finally, corresponding policy suggestions are provided for different types of countries participating in the nickel resource trade.
查看更多>>摘要：? 2022 Elsevier LtdThis study examines how the geopolitical oil price risk index, global gold price, global interest rate, and global exchange rate affect Islamic and conventional securities. For empirical estimation, this study has applied Quantile Autoregressive Distributive lag (QARDL) method on the monthly return of the Dow Jones conventional stock market index and Dow Jones Islamic Market World Index from January 2000 to November 2020. The primary variable of concern, geopolitical oil price risk, shows significant results for both securities under the bullish situation. Furthermore, under a bearish trend, the global exchange rate and the global interest rate of the Islamic stock market act in a similar direction. Although in conventional securities, both variables are significant in a bullish trend. The findings of this paper are important for investors and policymakers because this study provides a clear and comprehensive picture to shareholders in terms of their investments in Islamic or traditional markets. Moreover, it will open new opportunities for portfolio managers and speculators in Islamic and conventional stock markets.
查看更多>>摘要：? 2022This paper analyses the time and frequency dynamics of connectedness between cryptocurrencies and commodity sectors. It supports that cryptocurrency plays a virtual character in the global financial markets. The total spillovers from cryptocurrencies to commodity markets alternate during the COVID-19 period. The time-frequency domain spillover results illustrate that both in the short-run and long-run, cryptocurrencies contribute to the system as the main transmitter in risk spillover. Besides, the net spillover alternatives with time in different frequencies. The portfolio results illustrate that the hedging effect of cryptocurrencies varies among commodity sectors before and after COVID-19. After COVID-19 the cryptocurrencies show a better hedging tool in our system, especially the hedging effect of cryptocurrencies on ENTR and PMTR sectors. Furthermore, investors need to take cryptocurrencies into the portfolio and adjust the weight of cryptocurrencies according to the alternative hedging effectiveness index, especially after COVID-19.
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