Effects of emission control areas on sulfur-oxides concentrations--Evidence from the coastal ports in China.

The setting of Sulfur limitations in Emission Control Areas (ECAs) is a crucial action of marine environmental governance at the international regulatory levels. In this study, the overall and structural impacts of the two rounds of ECA policies on SOx concentrations were quantified using synthetic control method (SCM) based on time-series data from Chinese coastal ports from 2005 to 2020. From the outcomes, the 1st round of ECA policy announced in 2015 intensified the competition between ECA and non-ECA ports and provided strong support for ECA expansion and enhanced regulation in 2019. In addition, the restrictions on the Sulfur content of marine fuels under the 1st round of ECA policy has only effectively reduced the SOx concentration in the Bohai Rim and the Yangtze River Delta region, whereas the impact on the Pearl River Delta region isn't significant. However, the 2nd round of ECA policy has only effectively impacted the Bohai Rim. In general, the effect of the 1st round of ECA policy is better than that of the 2nd round, which is mainly because the favorable effect of the further expansion of ECA policy is offset by a significant increase in vessel activity in Chinese coastal ports.

Biochemical Pathways of Salicylic Acid Derived from l-Phenylalanine in Plants with Different Basal SA Levels.

As a plant hormone, salicylic acid (SA) has diverse regulatory roles in plant growth and stress resistance. Although SA is widely found in plants, there is substantial variation in basal SA among species. Tea plant is an economically important crop containing high contents of SA whose synthesis pathway remains unidentified. The phenylalanine ammonia-lyase (PAL) pathway is responsible for basal SA synthesis in plants. In this study, isotopic tracing and enzymatic assay experiments were used to verify the SA synthesis pathway in tea plants and evaluate the variation in phenylalanine-derived SA formation among 11 plant species with different levels of SA. The results indicated that SA could be synthesized via PAL in tea plants and conversion efficiency from benzoic acid to SA might account for variation in basal SA among plant species. This research lays the foundation for an improved understanding of the molecular regulatory mechanism for SA biosynthesis.

Impacts of the COVID-19 epidemic on carbon emissions from international shipping.

The COVID-19 epidemic made the most countries to take strict lockdown measures, what has seriously caused an unprecedented impact in the shipping industries, whereas these measures have also played a significant impact to control carbon emissions from international shipping. Here, we try to use the threshold generalized autoregressive conditional heteroscedasticity and the exponential generalized autoregressive heteroscedasticity to investigate whether the fluctuations of the control variable on carbon emissions from international shipping are asymmetric or not. On this basis, the GARCH-MIDAS model is introduced to discuss whether the newly confirmed cases are independent of control variables and have an impact on the fluctuation of carbon emissions. From the results, we find that the information contained in the newly confirmed cases cannot be covered when adding the other control variables. In addition, the newly confirmed cases have a negative impact on the volatility of carbon emissions, while the other control variables significantly increase carbon emissions. This study provides a quantitative research method for the analysis of the volatility and impact factors on international shipping carbon emissions, which helps to formulate more reasonable emission reduction measures and promote the low-carbon transformations of the global shipping industry.

The influence of COVID-19 epidemic on BDI volatility: An evidence from GARCH-MIDAS model.

In this study, we use the sample data from Jan 22, 2020 to Jan 21, 2022 to investigate the impacts of added infection number on the volatility of BDI. Under this structure, the control variables (freight rate, Brent crude oil price, container idle rate, port congestion level, global port calls) are added to test whether the information contained in the added infection number is covered. In the GARCH-MIDAS model, we divide the volatility of BDI into the long-term and short-term components, then employ in the least squares regression to empirically test the influences of added infection number on the volatility. From the analysis, we find the added infection numbers effectively impact the BDI volatility. In addition, whether the freight rate, Brent crude oil price, container idle rate, port congestion level, global port calls and other variables are considered alone or at the same time, further the added infection number still significantly influences the volatility of BDI. By studying the ability of the confirmed number to explain the volatility of BDI, a new insight is provided for the trend prediction of BDI that the shipping industry can take the epidemic development of various countries as a reference to achieve the purpose of cost or risk control.