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Rapid urbanization poses a threat to various ecosystem services. Beijing has undergone extensive infrastructure development in recent years. The study aims to extract land surface temperature (LST) and land use cover (LUC) data from satellite imagery, identify urban heat island (UHI) areas in Beijing, and determine the correlation between LST, LUC, NDVI, and BUI. It will also investigate the relationship between UHI and built/unbuilt areas, evaluate thermal comfort in Beijing using UTFVI, and assess the ecological quality of different land use types using the Ecological Evaluation Index (EEI). The results can inform urban planning and management in rapidly urbanizing and climate-changing regions. Changes in LUC and other activities affect the distribution of LST. For the study years (2005–2020), the estimated mean LST in Beijing was 24.72 °C, 27.07 °C, 26.22 °C, and 27.03 °C, respectively. A significant positive correlation (r = 0.96 p > 0.005) was found between LST and urban areas with other infrastructures. Geographically weighted regression (GWR) outperformed with Adj R2 > 0.74, suggesting that the extent of an urban heat island (UHI) is strongly dependent on the settlements, LUC composition, size, and terrain of surrounding communities. Urban hotspots in the city were identified and validated using Google Earth imagery. The Ecological Evaluation Index (EEI) value was relatively low compared to other ecosystem-related units. EEI showed a continuous increase of six percent in the most negative categories, indicating an unstable environment. This study concludes that urbanization affects the city’s environment, and study findings would help to regulate the urban ecosystem in Beijing.

Noise barriers need to be installed along high-speed railway lines to protect nearby inhabitants from the noise pollution caused by the running of high-speed trains (HSTs). The vertical noise barrier is the main structural type. However, when an HST passes through the noise barriers sited along the track, significant and transient aerodynamic pressure will act on the surface of the noise barriers, resulting in strong dynamic responses and even fatigue damage. Therefore, it is important to determine the train-induced aerodynamic load on the barrier surface and analyze the dynamic behaviors of the noise barriers under such a load for its structural design and to guarantee its safety and durability. This paper is a systematic review of the current literature on the aerodynamic load and dynamic behavior of vertical noise barriers; it includes (1) a summary and analysis of characteristics of such aerodynamic pressure and relevant influencing factors, (2) an introduction to measurement methods of aerodynamic load and relevant pressure models on the surface of noise barriers, and (3) a description of the dynamic response and fatigue analysis of noise barriers under such loads. Finally, potential further studies on this topic are discussed, and conclusions are drawn. Validerad;2023;Nivå 2;2023-06-12 (joosat);Licens fulltext: CC BY License

Background Clematis taxa are diverse, with high ornamental value. However, these plants have a complicated genetic background and a long growth period. Thus, molecular identifications are necessary to shorten the breeding cycle. Result Here, the genetic diversity of 17 parental taxa (five wild species and 12 Texas cultivars) were analyzed using inter simple sequence repeat (ISSR) markers. We obtained 108 alleles using 12 ISSR primers (an average of 9 alleles per primer). Genetic parameters, including the number of alleles (Na), the effective number of alleles (Ne), Nei's genetic diversity (H), and Shannon's diversity (I), suggested that these 17 taxa were highly diverse. Phylogenetic analysis recovered the 17 taxa in two large clades: one cluster included all of the cultivars, as well as Clematis pinnata, C. brevicaudata, and C. tubulosa; the second cluster included C. fusca and C. reticulata . The pairwise genetic distances between all cultivars were 0.421–2.368, suggesting that these cultivars may have derived from closely related species. We next performed five crosses between parental taxa and used ISSR markers to validate the authenticity of the 15 hybrid offspring. ISSR primers amplified bands specific to the male parents of each cross. Male parent-specific bands were identified in 11 of the 15 offspring; these 11 offspring were identified as true hybrids. The remaining progeny were considered self-hybrids due to the absence of male parent-specific bands. Conclusion Our results demonstrated that ISSR molecular markers may be useful tools for the verification of true Clematis hybrids. ISSR-based genetic diversity analyses, early hybrid identification, and marker assisted selection of Clematis taxa may improve breeding efficiency, excavate key genes associated with important traits, promote the development of new varieties, and shorten the breeding cycle