Disentangling the effects of geographic distance, environment and history on beta diversity of freshwater fish at a biogeographical crossroads.

Examining assemblage turnover and variation along geographic and environmental distances is a useful approach to evaluate beta diversity patterns and associated driving mechanisms. However, such studies are relatively limited in freshwater systems. Here, we compared the relationships between freshwater fish beta diversity and geographic distances among 165 hydrological units (HUs) in four zoogeographical regions (PA, Palearctic Region; CA, High Central Asia; EA, East Asia, SA, South Asia) across China and adjacent areas. This area can be considered a biogeographical crossroads, where faunal composition shares elements with different biogeographic and evolutionary origins. We found a considerably high level of between-HU overall dissimilarity (ßsor, range from ca. 0.60 to 0.85) in all four regions, mainly due to the turnover component (the relative contribution of ßsim to ßsor ranged from 60% to 90%). In general, ßsor and ßsim both significantly increased with geographic distance (except in PA), whereas the nestedness-resultant component (ßsne) decreased with geographic distance. The intercepts and slopes of the relationships between dissimilarities and distance (RDDs) both varied significantly among the four regions. The intercepts of ßsor and ßsim were both highest in SA, followed by CA, PA and EA, implying different levels of fish faunal heterogeneity at short distances. In contrast, the slopes of these two dissimilarities followed the decreasing trend from EA > CA > SA > PA, suggesting different environmental suitability and dispersal ability of fish species among regions. Variation partitioning in distance-based redundancy analysis showed that the spatial and historical factors were more important than area-heterogeneity and energy factors across all HUs and within three individual ecoregions (EA, SA and CA), but spatial factors were non-significant in PA. Our study highlighted the usefulness of RDDs in understanding biogeographical patterns and enhancing the biodiversity conservation of freshwater fishes.

[Application of Navosure impedance controlled endometrial ablation system in treating the intrauterine disease].

OBJECTIVE: To explore the feasibility, safety and effectiveness of treatment by Novasure system in abnormal uterine bleeding caused by endometrial polyps (AUB-P) or uterine leiomyomas up to 3 cm (AUB-LSM). METHODS: From June 2011 to June 2012, 30 women with abnormal uterine bleeding caused by AUB-P and AUB-LSM were treated by NoveSure system. The clinical efficacies and complications were followed up at months 1, 3, 6, 12. RESULTS: All operations were completed successfully. The mean operative duration was (84 ± 6) (60-120) s. The volume of blood loss was <10 ml. And the follow-up period was 1, 3, 6 and 12 months. The effective rate was 100% (30/30), 96.67% (29/30), 93.33% (28/30) and 96.67% (29/30) respectively. The rate of amenorrhea was 76.67% (23/30), 70% (21/30), 70% (21/30) and 76.67% (23/30) respectively. The degrees of satisfaction were 100% (30/30), 96.67% (29/30), 96.67% (29/30) and 96.67% (29/30).No severe perioperative or postoperative complications occurred. CONCLUSION: Navosure system is both safe and efficacious for abnormal uterine bleeding caused by AUB-P and AUB-LSM. And it is worth wider popularization.