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The erodibility parameters of barrier dam were an important basis for the evaluation of the outburst flood in the emergency treatment of the dammed lake. The erosion rate was typically modeled with excess shear stress model and Wilson model. However, there is no unified understanding of the range of erodibility parameters. In order to study the range of erodibility parameters of various types of soils and the relationship between the erodibility parameters of two models and soil properties, quickly determine the erodibility parameters of the dam, a database of 279 test results were collected from the literature review as well as by contacting researchers and organizations working on erosion around the world. The samples were classified into coarse-grained and fine-grained soils according to the unified soil classification system. Correlation analysis and regression analysis of the data were used to obtain the relationship between the erodibility parameters and soil properties. Four measures were used to evaluate the statistical significance of the relationship between erodibility parameters and soil parameters for coarse-grained and fine- grained soils: R² MSE Fvalue/Fstatistic and cross-validation. The erodibility parameters obtained from the experimental data were compared with the erodibility parameters predicted by the regression equation, the range of erodibility parameters of different soil and correlation between erosion parameters and soil parameters were obtained. According to the erodibility parameters database, the regression equation of erodibility parameters were obtained through statistical analysis of limited soil parameters and erodibility parameters to quickly predict the erosion rate of the soil. Finally, taking Baige weir plug as an example, according to the erodibility parameter database and statistical relationship established in this study, the erodibility parameters and erosion rate were analyzed rapidly. The research findings can be used to quickly determine the erosion parameters of the dam plug body, and provide help for rapid assessment of the risk of burst flood under emergency conditions. [ABSTRACT FROM AUTHOR]

Objective: To investigate the risk factors of cerebral metastasis of breast cancer and to provide guidance for the early diagnosis and treatment of brain metastases., Methods: Clinical data of postoperative patients with breast cancer were collected in our hospital from 2005 to 2009. All the patients were divided into two groups, with or without brain metastasis. The risk factors of brain metastases of patients with breast cancer were analyzed by the logistic regression., Results: Eight hundred and twenty four early postoperative patients with breast cancer were enrolled. The median follow-up time was 68 months and 199 cases had brain metastasis. The univariate logistic regression results showed that higher grade of tumor, <35 years, premenopausal, clinical stage Ⅲ, HER-2 positive and ER negative, no adjuvant chemotherapy, no adjuvant normal therapy were the risk factors of brain metastasis. The multivariate logistic regression result showed that higher grade of tumor, <35 years, premenopausal, clinical stage Ⅲ, HER-2 positive, ER negative were the risk factors. The mathematical model was used to predict the probability of occurrence of brain metastasis. ROC curve were draw by the value of predict probability as test variable and the brain metastasis status as state variables. The AUC value of this predictive model was 0.743±0.018. The specificity and sensitivity are relative high., Conclusion: Age<35 years, premenopausal, clinical stage Ⅲ, HER-2 positive and ER negative were independent risk factors for brain metastases. This model has the predictive value for the occurrence of brain metastases from breast cancer.