We studied the habitat preferences of Eurasian river otters (Lutra lutra) using the distribution patterns of the numbers of spraints and sprainting spots of otters, as well as related environmental variables (habitat zone, river management, bank type, vegetation coverage, width, depth, etc.) in two streams. The numbers of otter spraints and sprainting spots were sampled monthly in two streams on Geoje Island, Republic of Korea, from January to December 2004. Additional environmental variables were measured at the sampling sites. A self-organizing map (SOM), which is an unsupervised artificial neural network, was used to characterize the habitat preferences of otters. In our results, the SOM classified three different groups of study sites based on their habitat conditions, and the habitat differences were effectively visualized on the trained SOM map. Otters showed spatial and temporal dynamics in the numbers of spraints and sprainting spots, and revealed habitat preferences for shallow, narrow areas of streams and edges of water that were not far from reservoirs but covered with trees and shrubs. Additionally, otters preferred an environment in which weirs reduced the drift of water and gathered fishes and had a natural type of stream bank; these findings are relevant for river management. Otters adapted to places close to roads, residential areas, and agricultural areas with some tolerance of human interference.

This study aimed to compare the prognosis and characteristics of patients with advanced hepatocellular carcinoma treated with first-line atezolizumab plus bevacizumab (AB) combination therapy and hepatic artery infusion chemotherapy (HAIC). We retrospectively assessed 179 and 72 patients treated with HAIC and AB combination therapy, respectively, between January 2018 and January 2023. The progression-free survival of patients treated with HAIC was significantly superior than that of patients treated with AB (P<0.05), but there was no significant difference in overall survival and objective response rate (ORR) between the two groups (P=0.1056 and P=0.137, respectively). After propensity score matching (PSM), our data revealed that there was no significant difference in PFS between patients who received AB combination therapy and HAIC therapy (P=0.8888). However, patients who received AB combination therapy had significantly better overall survival than those who received HAIC therapy (P=0.0133). In addition, after PSM, significant differences in ORR and disease control rate were not observed. In conclusion, our propensity score study reveals that patients treated with AB therapy have a significantly longer OS than those treated with HAIC.

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