Analysis of shield tunnel response to bilateral pit excavation with a focus on perimeter pressure and deformation mechanisms.

This study aims to investigate the responses of shield tunnel structures subjected to disturbances caused by bilateral pit excavation, and it systematically reveals for the first time the impact mechanism of bilateral pit excavation on the distribution of perimeter pressure and deformation patterns of shield tunnels. Using a bilateral pit excavation project in Nanjing as a case study, this research establishes methods for calculating longitudinal displacement and circumferential pressure of tunnels under bilateral pit excavation conditions, employing the image source method for analysis. A refined three-ring segment model is developed, and the load structure method is used to analyze the impact of deep foundation excavation on the tunnel located between the two excavation sites.

N Addition Overwhelmed the Effects of P Addition on the Soil C, N, and P Cycling Genes in Alpine Meadow of the Qinghai-Tibetan Plateau.

Although human activities have greatly increased nitrogen (N) and phosphorus (P) inputs to the alpine grassland ecosystems, how soil microbial functional genes involved in nutrient cycling respond to N and P input remains unknown. Based on a fertilization experiment established in an alpine meadow of the Qinghai-Tibetan Plateau, we investigated the response of the abundance of soil carbon (C), N, and P cycling genes to N and P addition and evaluated soil and plant factors related to the observed effects. Our results indicated that the abundance of C, N, and P cycling genes were hardly affected by N addition, while P addition significantly increased most of them, suggesting that the availability of P plays a more important role for soil microorganisms than N in this alpine meadow ecosystem.

Effects of 5-Year Nitrogen Addition on Species Composition and Diversity of an Alpine Steppe Plant Community on Qinghai-Tibetan Plateau.

The N deposition rate is notably increased in China, especially in the Qinghai-Tibetan Plateau (QTP). How plants respond to the projected N deposition on the alpine steppe is still in debate. In this study, to investigate the effects of N deposition on the plant community of the alpine steppe, we simulated N deposition at six different N addition rate levels (0, 8, 24, 40, 56, 72 kg N ha y) from 2015 to 2019.

Analysis of transcripts and splice isoforms in Medicago sativa L. by single-molecule long-read sequencing.

The full-length transcriptome of alfalfa was analyzed with PacBio single-molecule long-read sequencing technology. The transcriptome data provided full-length sequences and gene isoforms of transcripts in alfalfa, which will improve genome annotation and enhance our understanding of the gene structure of alfalfa. As an important forage, alfalfa (Medicago sativa L.