Background Gestational diabetes mellitus （GDM） is a common complication during pregnancy,and gestational weight gain is one of the major and modifiable risk factors.This study aims to estimate the relationship betwe...Background Gestational diabetes mellitus （GDM） is a common complication during pregnancy,and gestational weight gain is one of the major and modifiable risk factors.This study aims to estimate the relationship between the rate of gestational weight gain before diagnosis of GDM and the subsequent risk of GDM.Methods A case-control study was conducted with 90 GDM cases and 165 women in the control group from May 2012 to August 2012 at Peking University First Affiliated Hospital.GDM was diagnosed according to the standards issued by the Ministry of Health of China in 2011.The plasma glucose levels,weights,and covariate data of the women were obtained based on medical records.Univariate analysis and unconditional Logistic regression model were used to estimate the associations.Results After adjusting for age at delivery,parity,and pre-pregnancy body mass index,the risk of GDM increased with increasing rates of gestational weight gain.Compared with the lower rate of gestational weight gain （less than 0.28 kg per week）,a rate of weight gain of 0.28 kg per week or more was associated with increased risk of GDM （odds ratio：2.03; 95％ confidence interval：1.15 to 3.59）.The association between the rate of gestational weight gain and GDM was primarily attributed to the increased weight gain in the first trimester.Conclusion High rates of gestational weight gain,particular during early pregnancy,may increase a woman＇s risk of GDM.展开更多
This article investigates gain self-scheduled H 1 robust control system design for a tailless fold- ing-wing morphing aircraft in the wing shape varying process. During the wing morphing phase, the aircraft＇s dynamic...This article investigates gain self-scheduled H 1 robust control system design for a tailless fold- ing-wing morphing aircraft in the wing shape varying process. During the wing morphing phase, the aircraft＇s dynamic response will be governed by time-varying aerodynamic forces and moments. Nonlinear dynamic equations of the morphing aircraft are linearized by using Jacobian linearization approach, and a linear parameter varying （LPV） model of the morphing aircraft in wing folding is obtained. A multi-loop controller for the morphing aircraft is formulated to guarantee stability for the wing shape transition process. The proposed controller uses a set of inner-loop gains to provide stability using classical techniques, whereas a gain self-scheduled H 1 outer-loop controller is devised to guarantee a specific level of robust stability and performance for the time-varying dynamics. The closed-loop simulations show that speed and altitude vary slightly during the whole wing folding process, and they converge rapidly after the process ends. This proves that the gain self-scheduled H 1 robust controller can guarantee a satisfactory dynamic performance for the morphing aircraft during the whole wing shape transition process. Finally, the flight control system＇s robustness for the wing folding process is verified according to uncertainties of the aerodynamic parameters in the nonlinear model.展开更多
In this paper, a rainfall-runoff modeling system is developed based on a nonlinear Volterra functional series and a hydrological conceptual modeling approach. Two models, i.e. the time-variant gain model (TVGM) and th...In this paper, a rainfall-runoff modeling system is developed based on a nonlinear Volterra functional series and a hydrological conceptual modeling approach. Two models, i.e. the time-variant gain model (TVGM) and the distributed time-variant gain model (DTVGM) that are built on the platform of Digital Elevation Model (DEM), Remote Sensing (RS) and Unit Hydro-logical Process were proposed. The developed DTVGM model was applied to two cases in the Heihe River Basin that is located in the arid and semiarid region of northwestern China and the Chaobai River basin located in the semihumid region of northern China. The results indicate that, in addition to the classic dynamic differential approach to describe nonlinear processes in hy-drological systems, it is possible to study such complex processes through the proposed sys-tematic approach to identify prominent hydrological relations. The DTVGM, coupling the advan-tages of both nonlinear and distributed hydrological models, can simulate variant hydrological processes under different environment conditions. Satisfactory results were obtained in fore-casting the time-space variations of hydrological processes and the relationships between land use/cover change and surface runoff variation.展开更多
Background:Weight gain during pregnancy reflects the mother's nutritional status.However, it may be affected by nutritional therapy and exercise interventions used to control blood sugar in gestational diabetes me...Background:Weight gain during pregnancy reflects the mother's nutritional status.However, it may be affected by nutritional therapy and exercise interventions used to control blood sugar in gestational diabetes mellitus (GDM).This study aimed to evaluate weight gain during gestation and pregnancy outcomes among women with GDM.Methods:A retrospective study involving 1523 women with GDM was conducted between July 2013 and July 2016.Demographic data, gestational weight gain (GWG), blood glucose, glycated-hemoglobin level, and maternal and fetal outcomes were extracted from medical records.Relationships between GWG and pregnancy outcomes were investigated using multivariate logistic regression.Results:In total, 451 (29.6%) women showed insufficient GWG and 484 (31.8%) showed excessive GWG.Excessive GWG was independently associated with macrosomia (adjusted odds ratio [aOR] 2.20, 95% confidence interval [CI] 1.50-3.52, P<0.001), large for gestational age (aOR 2.06, 95% CI 1.44-2.93, P<0.001), small for gestational age (aOR 0.49, 95% CI 0.25-0.97, P=0.040), neonatal hypoglycemia (aOR 3.80, 95% CI 1.20-12.00, P=0.023), preterm birth (aOR 0.45, 95% CI 0.21-0.96, P=0.040), and cesarean delivery (aOR 1.45, 95% CI 1.13-1.87, P=0.004).Insufficient GWG increased the incidence of preterm birth (aOR 3.53, 95% CI 1.96-6.37, P<0.001).Conclusions:Both excessive and insufficient weight gain require attention in women with GDM.Nutritional therapy and exercise interventions to control blood glucose should also be used to control reasonable weight gain during pregnancy to decrease adverse pregnancy outcomes.展开更多
文摘Background Gestational diabetes mellitus （GDM） is a common complication during pregnancy,and gestational weight gain is one of the major and modifiable risk factors.This study aims to estimate the relationship between the rate of gestational weight gain before diagnosis of GDM and the subsequent risk of GDM.Methods A case-control study was conducted with 90 GDM cases and 165 women in the control group from May 2012 to August 2012 at Peking University First Affiliated Hospital.GDM was diagnosed according to the standards issued by the Ministry of Health of China in 2011.The plasma glucose levels,weights,and covariate data of the women were obtained based on medical records.Univariate analysis and unconditional Logistic regression model were used to estimate the associations.Results After adjusting for age at delivery,parity,and pre-pregnancy body mass index,the risk of GDM increased with increasing rates of gestational weight gain.Compared with the lower rate of gestational weight gain （less than 0.28 kg per week）,a rate of weight gain of 0.28 kg per week or more was associated with increased risk of GDM （odds ratio：2.03; 95％ confidence interval：1.15 to 3.59）.The association between the rate of gestational weight gain and GDM was primarily attributed to the increased weight gain in the first trimester.Conclusion High rates of gestational weight gain,particular during early pregnancy,may increase a woman＇s risk of GDM.
基金co-supported by China Postdoctoral Science Foundation(Nos.20110490259,2012T50038)
文摘This article investigates gain self-scheduled H 1 robust control system design for a tailless fold- ing-wing morphing aircraft in the wing shape varying process. During the wing morphing phase, the aircraft＇s dynamic response will be governed by time-varying aerodynamic forces and moments. Nonlinear dynamic equations of the morphing aircraft are linearized by using Jacobian linearization approach, and a linear parameter varying （LPV） model of the morphing aircraft in wing folding is obtained. A multi-loop controller for the morphing aircraft is formulated to guarantee stability for the wing shape transition process. The proposed controller uses a set of inner-loop gains to provide stability using classical techniques, whereas a gain self-scheduled H 1 outer-loop controller is devised to guarantee a specific level of robust stability and performance for the time-varying dynamics. The closed-loop simulations show that speed and altitude vary slightly during the whole wing folding process, and they converge rapidly after the process ends. This proves that the gain self-scheduled H 1 robust controller can guarantee a satisfactory dynamic performance for the morphing aircraft during the whole wing shape transition process. Finally, the flight control system＇s robustness for the wing folding process is verified according to uncertainties of the aerodynamic parameters in the nonlinear model.
基金the Hundred Talents Program and Knowledge Innovation Key Project and the Outstanding Overseas Chinese Scholars Program of the Chinese Academy of Sciences(Grant No.KZCX2-SW-317/KZCX1-09-02) the National Natural Science Foundation of China(Grant No.50279049).
文摘In this paper, a rainfall-runoff modeling system is developed based on a nonlinear Volterra functional series and a hydrological conceptual modeling approach. Two models, i.e. the time-variant gain model (TVGM) and the distributed time-variant gain model (DTVGM) that are built on the platform of Digital Elevation Model (DEM), Remote Sensing (RS) and Unit Hydro-logical Process were proposed. The developed DTVGM model was applied to two cases in the Heihe River Basin that is located in the arid and semiarid region of northwestern China and the Chaobai River basin located in the semihumid region of northern China. The results indicate that, in addition to the classic dynamic differential approach to describe nonlinear processes in hy-drological systems, it is possible to study such complex processes through the proposed sys-tematic approach to identify prominent hydrological relations. The DTVGM, coupling the advan-tages of both nonlinear and distributed hydrological models, can simulate variant hydrological processes under different environment conditions. Satisfactory results were obtained in fore-casting the time-space variations of hydrological processes and the relationships between land use/cover change and surface runoff variation.
文摘Background:Weight gain during pregnancy reflects the mother's nutritional status.However, it may be affected by nutritional therapy and exercise interventions used to control blood sugar in gestational diabetes mellitus (GDM).This study aimed to evaluate weight gain during gestation and pregnancy outcomes among women with GDM.Methods:A retrospective study involving 1523 women with GDM was conducted between July 2013 and July 2016.Demographic data, gestational weight gain (GWG), blood glucose, glycated-hemoglobin level, and maternal and fetal outcomes were extracted from medical records.Relationships between GWG and pregnancy outcomes were investigated using multivariate logistic regression.Results:In total, 451 (29.6%) women showed insufficient GWG and 484 (31.8%) showed excessive GWG.Excessive GWG was independently associated with macrosomia (adjusted odds ratio [aOR] 2.20, 95% confidence interval [CI] 1.50-3.52, P<0.001), large for gestational age (aOR 2.06, 95% CI 1.44-2.93, P<0.001), small for gestational age (aOR 0.49, 95% CI 0.25-0.97, P=0.040), neonatal hypoglycemia (aOR 3.80, 95% CI 1.20-12.00, P=0.023), preterm birth (aOR 0.45, 95% CI 0.21-0.96, P=0.040), and cesarean delivery (aOR 1.45, 95% CI 1.13-1.87, P=0.004).Insufficient GWG increased the incidence of preterm birth (aOR 3.53, 95% CI 1.96-6.37, P<0.001).Conclusions:Both excessive and insufficient weight gain require attention in women with GDM.Nutritional therapy and exercise interventions to control blood glucose should also be used to control reasonable weight gain during pregnancy to decrease adverse pregnancy outcomes.
