RESUMO
Agricultural bioenergy utilization relies on crop and livestock production, favouring an integrated crop-livestock-bioenergy production model. Yet the integrated system's exact contribution to mitigating various environmental burdens from the crop production system and livestock production system remains unclear. Here we inventory the environmental impacts of each process in three subsystems at both national and regional scales in China, ultimately identifying key processes and impact categories. The co-benefits and trade-offs in nine impact categories are investigated by comparing the life cycle impacts in the background scenario (crop production system + livestock production system) and foreground scenario (integrated system). Freshwater eutrophication is the most serious impact category in both scenarios. Except terrestrial acidification, the mitigation effects on the other eight impact categories vary from 1.8% to 94.8%, attributed to fossil energy and chemical fertilizer offsets. Environmental trade-offs should be deliberated when expanding bioenergy utilization in the identified critical regions.
RESUMO
BACKGROUND: To distinguish left ventricular outflow tract (LVOT) from right ventricular outflow tract (RVOT) origin in idiopathic outflow tract premature ventricular contractions (IOT-PVCs) patients with precordial R/S transition at lead V3 is still a challenge. We sought to develop a new electrocardiography (ECG) method for distinguishing LVOT from RVOT origin in IOT-PVCs patients with precordial R/S transition at lead V3. METHODS: We analyzed the surface 12-lead ECG characteristics and the difference of coupling interval variability (CIV) of PVCs between distinct origin sites in a retrospective cohort of IOT-PVCs patients with precordial R/S transition at lead V3 who underwent successful radiofrequency catheter ablation (RFCA) to develop a new diagnostic method, then validated it in a prospective cohort. RESULTS: A total of 196 consecutive patients (41⯱â¯15â¯years, 36.7% male) underwent RFCA of IOT-PVCs between January 2014 and August 2016. Among them, 68 patients (34.7%, 23 male) with precordial R/S transition at lead V3 constituted the retrospective cohort. Based on the areas under the receiver operating characteristic curves (AUCs), a CIVâ¯>â¯100â¯ms with the largest value of AUC was selected to develop a new diagnostic method with a specificity of 93.9% and an accuracy of 92.6%. It correctly identified the origin site of 38 from 41 patients in the prospective cohort, demonstrating a 96.8% specificity and 92.7% accuracy. CONCLUSIONS: We presented a new simple method, a CIVâ¯>â¯100â¯ms which could reliably distinguish LVOT from RVOT origin in IOT-PVCs patients with precordial R/S transition at lead V3.
