A four-dimensional variational （4D-Var） data assimilation method is implemented in an improved intermediate coupled model （ICM） of the tropical Pacific. A twin experiment is designed to evaluate the impact of the ...A four-dimensional variational （4D-Var） data assimilation method is implemented in an improved intermediate coupled model （ICM） of the tropical Pacific. A twin experiment is designed to evaluate the impact of the 4D-Var data assimilation algorithm on ENSO analysis and prediction based on the ICM. The model error is assumed to arise only from the parameter uncertainty. The ＂observation＂ of the SST anomaly, which is sampled from a ＂truth＂ model simulation that takes default parameter values and has Gaussian noise added, is directly assimilated into the assimilation model with its parameters set erroneously. Results show that 4D-Var effectively reduces the error of ENSO analysis and therefore improves the prediction skill of ENSO events compared with the non-assimilation case. These results provide a promising way for the ICM to achieve better real-time ENSO prediction.展开更多
Background: Oral health has been implicated in low birth weight or preterm birth. However, this relationship has not yet been studied in twins. We investigated whether maternal oral health was associated with the birt...Background: Oral health has been implicated in low birth weight or preterm birth. However, this relationship has not yet been studied in twins. We investigated whether maternal oral health was associated with the birth weights of twins by a cross-sectional study conducted at Helsinki University Central Hospital. Methods: Utilizing linear mixed effect models to recognize the correlation between twins from the same mothers and the independence between different mothers. 40 birth weights of twins were modeled as main outcomes. In model 1, poor periodontal health (PPH) was fitted as the main explanatory variable. In model 2, presence of non-specific oral mucositis (NSOM) was fitted as the main predictor. Results: In model 1, babies from mothers with PPH weighed approximately 158.2 grams less than babies of mothers without PPH. However, this association was not statistically significant (p = 0.11). When a stricter criterion for PPH (3 sites of pocket depth > 4 mm) was used, p-value decreased to 0.09 showing a dose response to PPH. In model 2, mothers with NSOM had babies weighing 224.9 grams less than mothers without these lesions. This was nearly significant (p = 0.08). Conclusion: Although not significant, the results from this small data of twins suggest that maternal oral health may be associated with birth weight of twin neonates. Our results are appropriate to generate hypothesis for future studies.展开更多
基金supported by the National Natural Science Foundation of China(Grant Nos.41490644,41475101 and 41421005)the CAS Strategic Priority Project(the Western Pacific Ocean System+2 种基金Project Nos.XDA11010105,XDA11020306 and XDA11010301)the NSFC-Shandong Joint Fund for Marine Science Research Centers(Grant No.U1406401)the NSFC Innovative Group Grant(Project No.41421005)
文摘A four-dimensional variational （4D-Var） data assimilation method is implemented in an improved intermediate coupled model （ICM） of the tropical Pacific. A twin experiment is designed to evaluate the impact of the 4D-Var data assimilation algorithm on ENSO analysis and prediction based on the ICM. The model error is assumed to arise only from the parameter uncertainty. The ＂observation＂ of the SST anomaly, which is sampled from a ＂truth＂ model simulation that takes default parameter values and has Gaussian noise added, is directly assimilated into the assimilation model with its parameters set erroneously. Results show that 4D-Var effectively reduces the error of ENSO analysis and therefore improves the prediction skill of ENSO events compared with the non-assimilation case. These results provide a promising way for the ICM to achieve better real-time ENSO prediction.
文摘Background: Oral health has been implicated in low birth weight or preterm birth. However, this relationship has not yet been studied in twins. We investigated whether maternal oral health was associated with the birth weights of twins by a cross-sectional study conducted at Helsinki University Central Hospital. Methods: Utilizing linear mixed effect models to recognize the correlation between twins from the same mothers and the independence between different mothers. 40 birth weights of twins were modeled as main outcomes. In model 1, poor periodontal health (PPH) was fitted as the main explanatory variable. In model 2, presence of non-specific oral mucositis (NSOM) was fitted as the main predictor. Results: In model 1, babies from mothers with PPH weighed approximately 158.2 grams less than babies of mothers without PPH. However, this association was not statistically significant (p = 0.11). When a stricter criterion for PPH (3 sites of pocket depth > 4 mm) was used, p-value decreased to 0.09 showing a dose response to PPH. In model 2, mothers with NSOM had babies weighing 224.9 grams less than mothers without these lesions. This was nearly significant (p = 0.08). Conclusion: Although not significant, the results from this small data of twins suggest that maternal oral health may be associated with birth weight of twin neonates. Our results are appropriate to generate hypothesis for future studies.
