Search

In order to explore the causal relationship between the level of urban digital construction and urban economic growth, this paper takes 280 cities in China as the research object and constructs a comprehensive indicator evaluation system covering digital infrastructure, overall economic level, innovation development level, digital industry development status, and ecological environment conditions. Using the entropy method to weigh various indicators, this paper has obtained the evaluation results of the digital construction level of each city from 2011 to 2021. Furthermore, a panel data regression model is used to empirically analyze the impact of urban digital construction level on urban economic growth. The results show that for every 1% increase in the level of urban digital construction, the GDP will increase by 0.974. Through the above research, we hope to further enrich the theoretical and empirical research in the field of the digital economy, provide a scientific and reasonable method for quantitatively evaluating the level of urban digital construction, and provide decision-making references for improving the level of urban digital construction and promoting sustainable urban development. [ABSTRACT FROM AUTHOR]

Fujian province, an important tea-producing area in China, has abundant tea cultivars. To investigate the genetic relationships of tea plant cultivars in Fujian province and the characteristics of the tea plant varieties, a total of 70 tea cultivars from Fujian and other 12 provinces in China were subjected to restriction site-associated DNA sequencing (RAD-seq). A total of 60,258,975 single nucleotide polymorphism (SNP) sites were obtained. These 70 tea plant cultivars were divided into three groups based on analyzing the phylogenetic tree, principal component, and population structure. Selection pressure analysis indicated that nucleotide diversity was high in Southern China and genetically distinct from cultivars of Fujian tea plant cultivars, according to selection pressure analysis. The selected genes have significant enrichment in pathways associated with metabolism, photosynthesis, and respiration. There were ten characteristic volatiles screened by gas chromatography–mass spectrometry (GC–MS) coupled with multivariate statistical methods, among which the differences in the contents of methyl salicylate, 3-carene, cis-3-hexen-1-ol, (E)-4-hexen-1-ol, and 3-methylbutyraldehyde can be used as reference indicators of the geographical distribution of tea plants. Furthermore, a metabolome genome-wide association study (mGWAS) revealed that 438 candidate genes were related to the aroma metabolic pathway. Further analysis showed that 31 genes of all the selected genes were screened and revealed the reasons for the genetic differences in aroma among tea plant cultivars in Fujian and Southern China. These results reveal the genetic diversity in the Fujian tea plants as well as a theoretical basis for the conservation, development, and utilization of the Fujian highly aromatic tea plant cultivars. [ABSTRACT FROM AUTHOR]

China's large-scale construction has led to massive energy consumption and carbon emissions. The embodied carbon emissions (ECs) of China's building sector play a key role in realizing national emission reduction targets. Currently, the understanding of the status quo of ECs is vague and inconsistent, and the existing accounting models still have several limitations. Therefore, this study develops two improved models (i.e., the process-based and the input-output-based life cycle assessment models) and dynamic accounting datasets to reveal historical trends and emission characteristics of ECs from 2005 to 2020. The results show that the total ECs in 2020 were as high as 2.28 billion tCO2, accounting for 25.2% of China's total energy-related carbon emissions. The indirect ECs are the largest contributor, representing 95.9% of the total building ECs. The ECs increased quickly at first and entered a plateau, stable at about 2.2 billion tCO2 after 2015. From 2005 to 2020, the total building ECs contributed 38.7% to the national carbon emission growth, while the intensity of ECs showed a downward trend, indicating that the increase in China's building ECs is scale-driven. This study provides sound methodological, and data support for emission tracing and the low-carbon development of China's building sector. [ABSTRACT FROM AUTHOR]

Quality control of Chinese herbal tea remains a challenge due to our poor knowledge of their complex chemical profile. This study aims to investigate the chemical composition of one of the best-selling and famous brand of beverage in China, Wanglaoji Herbal Tea (WLJHT), via a full component quantitative analysis. In this paper, a total of thirty-four representative constituents were identified or tentatively characterized using ultra-high performance liquid chromatography coupled with quadrupole tandem time-of-flight mass spectrometry (UPLC-Q-TOF-MS). Moreover, the quantitative analyses of fourteen constituents were performed by high performance liquid chromatography with a triple quadruple tandem mass spectrometry (HPLC-MS/MS) method and saccharide compositions of WLJHT were also quantitatively determined by high performance liquid chromatography (HPLC) with evaporative light scattering detector (ELSD) on a Hilic column, separately. Using multiple chromatographic techniques presented a good precision, sensitivity, repeatability and stability, and was successfully applied to analyze 16 batches of WLJHT samples. Therefore, it would be a reliable and useful approach for the quality control of WLJHT. [ABSTRACT FROM AUTHOR]