The asymptotic solution to the scattering problem on a set of small particles, supplemented into homogeneous material, is used for modeling the materials with the desired refractive index. The consideration concerns t...The asymptotic solution to the scattering problem on a set of small particles, supplemented into homogeneous material, is used for modeling the materials with the desired refractive index. The consideration concerns the case of acoustic scalar scattering and the solution to initial scattering problem is built using an asymptotic approach. The closed form solution is reduced for the scattering problem. This is significant advantage of approach because there is no need to solve the respective system of boundary integral equations. High accuracy of solving the scattering problem is achieved by choosing the optimal parameters of the domain with small particles. The approach allows obtaining an explicit formula for the refractive index of the resulting inhomogeneous material. The numerical calculations show the possibility to get the specific values of refractive index including its negative values.展开更多
目的探讨不同程度小于胎龄儿(small for gestational age,SGA)发生的影响因素,为早期识别重度SGA的发生提供依据。方法回顾性收集2018年1月—2022年12月北京大学人民医院产科出生的新生儿及其母亲围产期资料。新生儿分为重度SGA组(出生...目的探讨不同程度小于胎龄儿(small for gestational age,SGA)发生的影响因素,为早期识别重度SGA的发生提供依据。方法回顾性收集2018年1月—2022年12月北京大学人民医院产科出生的新生儿及其母亲围产期资料。新生儿分为重度SGA组(出生体重低于同胎龄同性别婴儿的第3百分位数)、轻度SGA组(出生体重≥第3百分位数且<第10百分位数)和非SGA组(出生体重≥第10百分位数)。采用有序多分类logistic回归模型分析不同程度SGA发生的影响因素。结果共纳入14821例新生儿,其中重度SGA组258例(1.74%),轻度SGA组902例(6.09%),非SGA组13661例(92.17%)。早产儿比例和死产比例均为重度SGA组>轻度SGA组>非SGA组(P<0.0125);重度SGA组与轻度SGA组新生儿窒息比例均大于非SGA组(P<0.0125)。有序多分类logistic回归分析显示:母孕前消瘦(OR=1.838)、母孕前肥胖(OR=3.024)、体外受精-胚胎移植(OR=2.649)、妊娠合并子痫前期(OR=1.743)、妊娠合并结缔组织病(OR=1.795)、脐带绕颈(OR=1.213)、羊水少(OR=1.848)、宫内生长受限(OR=27.691)等均与发生更严重的SGA有关(P<0.05);孕母为经产妇(OR=0.457)更倾向于不发生严重的SGA(P<0.05)。结论母孕前消瘦、母孕前肥胖、体外受精-胚胎移植、妊娠合并子痫前期、妊娠合并结缔组织病、羊水少、脐带绕颈、宫内生长受限与更严重的SGA发生密切相关;孕母为经产妇是发生严重SGA的保护因素。展开更多
目的探讨妊娠期糖尿病(gestational diabetes mellitus,GDM)患者妊娠早期甘油三酯葡萄糖指数(the triglyceride-gluscose index,TyG指数)与分娩小于胎龄儿(small for gestational age infant,SGA)之间的关系。方法选取2018年1月至2023年...目的探讨妊娠期糖尿病(gestational diabetes mellitus,GDM)患者妊娠早期甘油三酯葡萄糖指数(the triglyceride-gluscose index,TyG指数)与分娩小于胎龄儿(small for gestational age infant,SGA)之间的关系。方法选取2018年1月至2023年6月复旦大学附属上海市第五人民医院和新疆喀什地区第二人民医院产科孕早期建档并符合纳入标准的孕妇1532例为研究对象,根据孕妇24~28周行口服葡萄糖耐量试验(oral glucose tolerance test,OGTT)结果,将其分为GDM组(754例)及非GDM组(778例)。GDM组患者根据新生儿体重,将其分为SGA组、大于胎龄儿(large for gestational age infant,LGA)组和适于胎龄儿(appropriate for gestational age infant,AGA)组。分析GDM患者分娩SGA的独立影响因素,采用Logistic回归模型分析TyG指数与发生SGA的相关性。绘制ROC曲线以分析妊娠早期TyG指数对GDM患者分娩SGA的预测价值。结果GDM患者SGA组TyG指数显著低于LGA组、AGA组及非GDM组(P<0.05);多因素Logistic回归分析结果显示,TyG指数与GDM患者分娩SGA的发生独立相关(P<0.05);ROC曲线结果显示,妊娠早期TyG指数对GDM患者分娩SGA具有较好的预测价值(AUC=0.821,95%CI:0.763~0.879,P<0.001)。结论GDM患者妊娠早期TyG指数与分娩SGA之间存在独立相关,对于GDM患者分娩SGA具有较好的预测价值。展开更多
Ascertaining the relationship between "source-sink" landscape and non-point source(NPS) pollution is crucial for reducing NPS pollution, however, it is not easy to realize this target on cell unit scale. To ...Ascertaining the relationship between "source-sink" landscape and non-point source(NPS) pollution is crucial for reducing NPS pollution, however, it is not easy to realize this target on cell unit scale. To reveal the relationships between "sourcesink" landscape and NPS pollution based on cell units of a small catchment in the Three Gorges Reservoir Region(TGRR), the runoff and nutrient yields were simulated first by rainfall events on a cell unit scale based on the Annualized AGricultural Non-Point Source Pollution Model(AnnAGNPS). Landscape structure and pattern were quantified with "sourcesink" landscape indicators based on cell units including landscape area indices and locationweighted landscape indices. The results showed that:the study case of small Wangjiagou catchment highlighted a good prediction capability of runoff and nutrient export by the AnnAGNPS model. Throughout the catchment, the spatial distribution trends of four location-weighted landscape indices were similar to the trends of simulated total nitrogen(TN) and total phosphorus(TP), which highlighted the importance of spatial arrangement of "source" and "sink" landscape types in a catchment when estimating pollutant loads. Results by Pearson correlation analysis indicated that the location-weighted landscape index provided a more comprehensive account of multiple factors, and can better reflect NPS-related nutrient loss than other landscape indices applied in single-factor analysis. This study provides new findings for applying the "source-sink" landscape indices based on cell units in small catchments to explain the effect of "source-sink" landscape on nutrient export based on cell unit, and helps improve the understanding of the correlation between "source-sink" landscape and NPS pollution.展开更多
文摘The asymptotic solution to the scattering problem on a set of small particles, supplemented into homogeneous material, is used for modeling the materials with the desired refractive index. The consideration concerns the case of acoustic scalar scattering and the solution to initial scattering problem is built using an asymptotic approach. The closed form solution is reduced for the scattering problem. This is significant advantage of approach because there is no need to solve the respective system of boundary integral equations. High accuracy of solving the scattering problem is achieved by choosing the optimal parameters of the domain with small particles. The approach allows obtaining an explicit formula for the refractive index of the resulting inhomogeneous material. The numerical calculations show the possibility to get the specific values of refractive index including its negative values.
文摘目的探讨不同程度小于胎龄儿(small for gestational age,SGA)发生的影响因素,为早期识别重度SGA的发生提供依据。方法回顾性收集2018年1月—2022年12月北京大学人民医院产科出生的新生儿及其母亲围产期资料。新生儿分为重度SGA组(出生体重低于同胎龄同性别婴儿的第3百分位数)、轻度SGA组(出生体重≥第3百分位数且<第10百分位数)和非SGA组(出生体重≥第10百分位数)。采用有序多分类logistic回归模型分析不同程度SGA发生的影响因素。结果共纳入14821例新生儿,其中重度SGA组258例(1.74%),轻度SGA组902例(6.09%),非SGA组13661例(92.17%)。早产儿比例和死产比例均为重度SGA组>轻度SGA组>非SGA组(P<0.0125);重度SGA组与轻度SGA组新生儿窒息比例均大于非SGA组(P<0.0125)。有序多分类logistic回归分析显示:母孕前消瘦(OR=1.838)、母孕前肥胖(OR=3.024)、体外受精-胚胎移植(OR=2.649)、妊娠合并子痫前期(OR=1.743)、妊娠合并结缔组织病(OR=1.795)、脐带绕颈(OR=1.213)、羊水少(OR=1.848)、宫内生长受限(OR=27.691)等均与发生更严重的SGA有关(P<0.05);孕母为经产妇(OR=0.457)更倾向于不发生严重的SGA(P<0.05)。结论母孕前消瘦、母孕前肥胖、体外受精-胚胎移植、妊娠合并子痫前期、妊娠合并结缔组织病、羊水少、脐带绕颈、宫内生长受限与更严重的SGA发生密切相关;孕母为经产妇是发生严重SGA的保护因素。
文摘目的探讨妊娠期糖尿病(gestational diabetes mellitus,GDM)患者妊娠早期甘油三酯葡萄糖指数(the triglyceride-gluscose index,TyG指数)与分娩小于胎龄儿(small for gestational age infant,SGA)之间的关系。方法选取2018年1月至2023年6月复旦大学附属上海市第五人民医院和新疆喀什地区第二人民医院产科孕早期建档并符合纳入标准的孕妇1532例为研究对象,根据孕妇24~28周行口服葡萄糖耐量试验(oral glucose tolerance test,OGTT)结果,将其分为GDM组(754例)及非GDM组(778例)。GDM组患者根据新生儿体重,将其分为SGA组、大于胎龄儿(large for gestational age infant,LGA)组和适于胎龄儿(appropriate for gestational age infant,AGA)组。分析GDM患者分娩SGA的独立影响因素,采用Logistic回归模型分析TyG指数与发生SGA的相关性。绘制ROC曲线以分析妊娠早期TyG指数对GDM患者分娩SGA的预测价值。结果GDM患者SGA组TyG指数显著低于LGA组、AGA组及非GDM组(P<0.05);多因素Logistic回归分析结果显示,TyG指数与GDM患者分娩SGA的发生独立相关(P<0.05);ROC曲线结果显示,妊娠早期TyG指数对GDM患者分娩SGA具有较好的预测价值(AUC=0.821,95%CI:0.763~0.879,P<0.001)。结论GDM患者妊娠早期TyG指数与分娩SGA之间存在独立相关,对于GDM患者分娩SGA具有较好的预测价值。
基金supported by the National Natural Science Foundation of China (Nos. 41671291)
文摘Ascertaining the relationship between "source-sink" landscape and non-point source(NPS) pollution is crucial for reducing NPS pollution, however, it is not easy to realize this target on cell unit scale. To reveal the relationships between "sourcesink" landscape and NPS pollution based on cell units of a small catchment in the Three Gorges Reservoir Region(TGRR), the runoff and nutrient yields were simulated first by rainfall events on a cell unit scale based on the Annualized AGricultural Non-Point Source Pollution Model(AnnAGNPS). Landscape structure and pattern were quantified with "sourcesink" landscape indicators based on cell units including landscape area indices and locationweighted landscape indices. The results showed that:the study case of small Wangjiagou catchment highlighted a good prediction capability of runoff and nutrient export by the AnnAGNPS model. Throughout the catchment, the spatial distribution trends of four location-weighted landscape indices were similar to the trends of simulated total nitrogen(TN) and total phosphorus(TP), which highlighted the importance of spatial arrangement of "source" and "sink" landscape types in a catchment when estimating pollutant loads. Results by Pearson correlation analysis indicated that the location-weighted landscape index provided a more comprehensive account of multiple factors, and can better reflect NPS-related nutrient loss than other landscape indices applied in single-factor analysis. This study provides new findings for applying the "source-sink" landscape indices based on cell units in small catchments to explain the effect of "source-sink" landscape on nutrient export based on cell unit, and helps improve the understanding of the correlation between "source-sink" landscape and NPS pollution.
