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Due to rapid homogenization in habitat types as a result of urbanization, some urban birds adapt their nesting strategies to changes in local habitat characteristics. Bird nesting decisions might have been mainly linked to resource constraints and ensuring reproductive success. In this study, we examined patterns of nesting behavior by spotted doves (Spilopelia chinensis) in a rapidly urbanizing area of Nanchang, China using ArcGIS 10.8, satellite tracking, camera traps, and field survey. To explore the mechanisms underlying nesting behavior in urban habitats, we assessed the correlations between nest reuse and reproductive success, and between nest reuse and nest predation. From December 2018 to December 2021, a total of 302 breeding nests were surveyed. The results revealed that the nest reuse rate was 38.08% (n = 115). Nests closer to trunk, with lower nest position and higher large‐scale urbanization score tended to have higher reuse rate. In addition, nests with the higher the nest height and percent of canopy cover, and the lower small‐scale urbanization score were more likely to reproduce successfully, and the reused nests also reproduce more successfully. The reproductive success associated with nest reuse was significantly higher than that associated with new nests (χ2 = 8.461, p =.004). High degree of urbanization promoted nest reuse of spotted doves (large‐scale urbanization score, z = 2.094, p =.036), which apparently enhanced their reproductive success (nest reuse, z = 2.737, p =.006). In conclusion, a nest structure with good permeability is the material basis for the nest reuse in spotted dove, while the relatively low risk of predation in urban habitat and the scarcity of nest site resources due to urbanization increase the tendency of birds to reuse old nests, which is associated with their reproductive success and evolutionary fitness. [ABSTRACT FROM AUTHOR]

Taking the involute spur gear pairs with profile shift as the research object, the mesh stiffness calculation models including nonlinear Hertzian contact stiffness, tooth profile curve, fillet foundation stiffness with structure coupling effect were established based on the potential energy method. Considering the influences of gear profile shifts, the calculation formulas for tooth profile curve, half tooth angle of base circle and half tooth angle of dedendum circle in mesh stiffness calculation were revised. The fillet foundation stiffness models were revised by considering tooth surface frictions. The pressure angle models of gear mesh point were derived by considering geometric eccentricity errors. The effects of profile shifted, tooth surface frictions and geometric eccentricity errors on mesh stiffness were studied. The results show that the center distance, stiffness amplitude and contact ratio of the profile shifted gear pairs have great changes. Owing to the profile shift, the moment when the direction of frictional force changes on a pair of meshing gears no longer occurs within the single tooth meshing interval, thereby affecting the characteristics of the mesh stiffness. Geometric eccentricity increases the peak-to-peak values of the mesh stiffness, and at the same time, sideband frequencies with intervals corresponding to the rotational frequencies appear in the frequency domain of the meshing stiffness. In the presence of eccentricity errors in both the driving and driven gears, a new sideband frequency arises with an interval equal to the difference in rotation frequency. Considering the combined effects of three factors, the mesh stiffness characteristics may be significantly influenced. The research results provide the references for further researches of the dynamics of profile shifted gears. [ABSTRACT FROM AUTHOR]