Effects of Different Inflow Rate Patterns and Distributions of Grass Strips on Runoff and Sediment in an Engineering Accumulation Body

Engineering accumulation bodies are critical sources of artificial soil and water loss. The objectives of this study were to evaluate the effects of different inflow rate patterns and distributions of grass strips on runoff and sediment in engineering accumulation bodies. A field runoff plot (20 m long, 1 m wide, and 0.5 m deep) was used for inflow simulation experiments under four inflow rate patterns (even, rising, falling, and rising-falling) and five grass strip patterns (patterns Ⅰ-Ⅴ). The results showed that the changing trends of runoff rate and sediment yield increased with increasing inflow rate and decreased with reduction for the same grass strip pattern. Although the inflow rate pattern affected runoff and sediment yield, it had no significant effect on the total runoff and sediment. The influence of the grass strip pattern on runoff and sediment was significantly higher than that of the inflow rate pattern. The runoff reduction and sediment reduction effects of grass strip patterns were 12.23 to 49.62% and 12.92 to 80.54%, respectively. When grass strips were distributed on a slope in bands (pattern Ⅴ), the soil and water conservation effects were ideal, reducing the average runoff and sediment by 44.98% and 58.09%, respectively. Sediment reduction caused by decreasing runoff (SRR) was the main factor controlling erosion and sediment yield. This study can guide the configuration of vegetation control measures for soil and water loss in engineering accumulation bodies.

Recognition of the anatomical structure of the atrioventricular node: Connection between the retroaortic node and the compact node

Introduction: The complex electrophysiological phenomena related to the atrioventricular node (AVN) are due to its complex anatomical structures. Aside from the inferior nodal extension (INE), other node-like tissues, such as the retroaortic node (RN), have been less described and may also share the mechanism of normal conduction and abnormal conduction in AVN re-entrant tachycardia (AVNRT). Methods: High-density sections of the entire AVN were obtained from rats and rabbits. Fibrosis was analyzed by Masson’s trichrome staining. Connexin (Cx43, Cx40, and Cx45) and ion channel (Nav1.5, Cav3.1, and HCN4) proteins were immunohistochemically labeled for the analysis of tissue features. Three-dimensional (3D) reconstruction of the AV junction was performed to clarify the relationships among different structures. Results: The RN expressed the same connexin isoforms as the compact node (CN) and INE. Nav1.5 labeling was present at a low level in the CN, RN and INE, where Cav3.1 and HCN4 were expressed. The CN connected with the RN in a narrow strip pattern at the level of the start of the CN. The RN presented as a shuttle shape and was the only tissue directly connected with the atrium in the anterior septum. Conclusion: The RN connects with the AVN anatomically, suggesting that there is direct electrical conduction between them. The entrance of the atria into the AVN is the distal part of the RN, which may form the fast pathway of the AVN.

Analysis on High-Energy Physical Problems in Monte Carlo Simulation

This paper analyzes the data got in two Monte Carlo simulations, namely, extensive air shower simulation and detector simulation. Then, based on the data from experimental arrays, some physical problems have been analyzed and illustrated. Those problems include the distribution of energy spectrum of secondary particles, the distribution of zenith angle, of azimuths, of background noises, and that of strip pattern, as well as the atmospheric absorption.