Evaluation of best management practices for mitigating harmful algal blooms risk in an agricultural lake basin using a watershed model integrated with Bayesian Network approach.

Lake eutrophication caused by nitrogen and phosphorus has led to frequent harmful algal blooms (HABs), especially under the unknown challenges of climate change, which have seriously damaged human life and property. In this study, a coupled SWAT-Bayesian Network (SWAT-BN) model framework was constructed to elucidate the mechanisms between non-point source nitrogen pollution in agricultural lake watersheds and algal activities. A typical agricultural shallow lake basin, the Taihu Basin (TB), China, was chosen in this study, aiming to investigate the effectiveness of best management practices (BMPs) in controlling HABs risks in TB. By modeling total nitrogen concentration of Taihu Lake from 2007 to 2022 with four BMPs (filter strips, grassed waterway, fertilizer application reduction and no-till agriculture), the results indicated that fertilizer application reduction proved to be the most effective BMP with 0.130 of Harmful Algal Blooms Probability Reduction (HABs-PR) when reducing 40% of fertilizer, followed by filter strips with 0.01 of HABs-PR when 4815ha of filter strips were conducted, while grassed waterway and no-till agriculture showed no significant effect on preventing HABs. Furthermore, the combined practice between 40% fertilizer application reduction and 4815ha filter strips construction showed synergistic effects with HABs-PR increasing to 0.171. Precipitation and temperature data were distorted to model scenarios of extreme events. As a result, the combined approach outperformed any single BMP in terms of robustness under extreme climates. This research provides a watershed-level perspective on HABs risks mitigation and highlights the strategies to address HABs under the influence of climate change.

Therapeutic effect of an external fixator in the treatment of unstable pelvic fractures in children.

BACKGROUND: Unstable pelvic fractures in children are serious and complex injuries, and the optimal method to manage these injuries is controversial. HYPOTHESIS: We hypothesized that an external fixator would be a satisfactory method of treating unstable pelvic fractures in children. PATIENTS AND METHODS: We retrospectively reviewed 40 pediatric patients with unstable pelvic fractures who were treated with an external fixator in Beijing Children's Hospital from June 2006 to June 2016. Postoperative follow-up was 12 to 108 months, with an average of 26 months. One year after the operation, fracture healing, pelvic asymmetry, and deformity index were assessed by X-ray. Pelvic function was evaluated with the Cole evaluation standard, and daily cognitive and motor functions were evaluated by weeFIM. Patient complications were recorded. RESULTS: The average age of the 40 patients was 5.9±3.1 years (2 to 14.5), including 25 boys and 15 girls. Among these cases, 37 (92.5%) had injuries caused by traffic accidents and 3 (7.5%) had injuries caused by falling from height. Based on the Tile classification, there were 18 cases of class B (14 class B2 and 4 class B3) and 22 cases of class C (15 class C1, 6 class C2, and 1 class C3). The X-rays showed good fracture healing at the 1-year postoperative follow-up. The pelvic asymmetry was reduced from 1.13cm before the operation to 0.88cm after (p<0.05), and the deformity index was decreased from 0.09 before to 0.05 after the operation (p<0.05). At the 1-year postoperative follow-up, 36 patients had excellent Cole scores, and 4 had good Cole scores, with a good or excellent rate of 100%. According to the weeFIM, 28 patients had complete independence, 11 had basic independence, and 1 had conditional independence. Three patients (7.5%) had complications, all of which were postoperative pin-site infections. DISCUSSION: For children with horizontally unstable pelvic fractures, an external fixator can be used alone. For children with horizontally and vertically unstable pelvic fractures, after external fixator placement and reduction, lower extremity traction can be performed to achieve better reduction and maintain stability, and the therapeutic effect is satisfactory. LEVEL OF EVIDENCE: IV, retrospective observational cohort study.