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树皮含硫量的变化及其在监测冬季大气SO2污染中的应用 被引量:7
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作者 刘荣坤 蒋放 田德林 《Acta Botanica Sinica》 CSCD 1992年第8期622-629,共8页
树木当年生枝条不同部位的含硫量是:叶>树皮>木材,其数值因树种、季节而异,并与大气 SO_2浓度呈正相关。落叶冬眠枝条的皮部具有明显的吸硫能力,其含硫量与皮孔总开度及皮部结构有关。本文提出用皮部含硫量监测冬季大气 SO_2浓度... 树木当年生枝条不同部位的含硫量是:叶>树皮>木材,其数值因树种、季节而异,并与大气 SO_2浓度呈正相关。落叶冬眠枝条的皮部具有明显的吸硫能力,其含硫量与皮孔总开度及皮部结构有关。本文提出用皮部含硫量监测冬季大气 SO_2浓度的回归方程和预测图,并对沈阳部分采样点的冬季大气 SO_2污染状况进行评价,与理化监测结果完全一致。 展开更多
关键词 加拿大肠 树皮含硫量 冬季 大气SO2
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Validation of the Rockall scoring system for outcomes from non-variceal upper gastrointestinal bleeding in a Canadian setting 被引量:14
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作者 Robert A Enns Yves M Gagnon +4 位作者 Alan N Barkun David Armstrong Jamie C Gregor Richard N Fedorak RUGBE Investigators Group 《World Journal of Gastroenterology》 SCIE CAS CSCD 2006年第48期7779-7785,共7页
AIM: To validate the Rockall scoring system for predicting outcomes of rebleeding, and the need for a surgical procedure and death. METHODS: We used data extracted from the Registry of Upper Gastrointestinal Bleeding ... AIM: To validate the Rockall scoring system for predicting outcomes of rebleeding, and the need for a surgical procedure and death. METHODS: We used data extracted from the Registry of Upper Gastrointestinal Bleeding and Endoscopy including information of 1869 patients with non-variceal upper gastrointestinal bleeding treated in Canadian hospitals. Risk scores were calculated and used to classify patients based on outcomes. For each outcome, we used χ2 goodness-of-fit tests to assess the degree of calibration, and built receiver operating characteristic curves and calculated the area under the curve (AUC) to evaluate the discriminative ability of the scoring system. RESULTS: For rebleeding, the χ2 goodness-of-fit test indicated an acceptable fit for the model [χ2 (8) = 12.83, P = 0.12]. For surgical procedures [χ2 (8) = 5.3, P = 0.73] and death [χ2 (8) = 3.78, P = 0.88], the tests showed solid correspondence between observed proportions and predicted probabilities. The AUC was 0.59 (95% CI: 0.55-0.62) for the outcome of rebleeding and 0.60 (95% CI: 0.54-0.67) for surgical procedures, representing apoor discriminative ability of the scoring system. For the outcome of death, the AUC was 0.73 (95% CI: 0.69-0.78), indicating an acceptable discriminative ability. CONCLUSION: The Rockall scoring system provides an acceptable tool to predict death, but performs poorly for endpoints of rebleeding and surgical procedures. 展开更多
关键词 Upper gastrointestinal bleeding Nonvariceal PREDICTORS Rockall OUTCOMES
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