追踪研究当中,交叉滞后模型可以探究多变量之间往复式影响,潜增长模型可以探究个体增长趋势。对两类模型进行整合,例如同时关注往复式影响与个体增长趋势,同时可以定义测量误差、随机截距等变异成分,衍生出随机截距交叉滞后模型、特质−...追踪研究当中,交叉滞后模型可以探究多变量之间往复式影响,潜增长模型可以探究个体增长趋势。对两类模型进行整合,例如同时关注往复式影响与个体增长趋势,同时可以定义测量误差、随机截距等变异成分,衍生出随机截距交叉滞后模型、特质−状态−误差模型、自回归潜增长模型、结构化残差潜增长模型等。以交叉滞后模型和潜增长模型分别作为基础模型,从个体间/个体内变异分解的角度对上述各类模型梳理,整合出此类模型的分析框架,并拓展建立“因子结构化潜增长模型(factor latent curve model with structured reciprocals)”作为统合框架。通过实证研究(早期儿童的追踪研究−幼儿园版,ECLS-K),建立21049名儿童的阅读和数学能力的往复式影响与增长趋势。研究发现,分离了稳定特质的模型拟合最优。研究也对模型建模思路和模型选择提供了建议。展开更多
The asymmetric semi-circular bend(ASCB)specimen has been proposed to investigate the cracking behavior in different geo and construction materials and attracted the attention of researchers due to its advantages.Howev...The asymmetric semi-circular bend(ASCB)specimen has been proposed to investigate the cracking behavior in different geo and construction materials and attracted the attention of researchers due to its advantages.However,there are few studies on the fracture toughness determination of rock materials.In this work,a series of fracture tests were performed with the ASCB specimens made of granite.The onset of fracture,crack initiation angle and crack propagating trajectory was analyzed in detail combined with several mixed mode fracture criteria.The influence of the crack length on the mode Ⅰ/Ⅱ fracture toughness was studied.A comparison between the fracture toughness ratios predicted by varying criteria and experimental results was conducted.The relationship between experimentally determined crack initiation angles and curves of the generalized maximum tangential stress(GMTS)criterion was obtained.The fracture process of the specimen was recorded with the high-speed camera.The shortcomings of the ASCB specimens for the fracture toughness determination of rock materials were discussed.The results may provide a reference for analysis of mixed mode I and II fracture behavior of brittle materials.展开更多
This study aimed to investigate whether fetal growth trajectories(FGTs)could predict early childhood development,indicate intrauterine metabolic changes,and explore potential optimal and suboptimal FGTs.FGTs were deve...This study aimed to investigate whether fetal growth trajectories(FGTs)could predict early childhood development,indicate intrauterine metabolic changes,and explore potential optimal and suboptimal FGTs.FGTs were developed by using an unsupervised machine-learning approach.Children’s neurodevelopment,anthropometry,and respiratory outcomes in thefirst 6 years of life were assessed at different ages.In a subgroup of participants,we conducted a metabolomics analysis of cord blood to reveal the metabolic features of FGTs.We identified 6 FGTs:early decelerating,early decelerating with late catch-up growth,early accelerating,early accelerating with late medium growth,late decelerating,and late accelerating.The early accelerating with late medium growth pattern might be the optimal FGT due to its associations with better psychomotor development,mental development,intelligence quotient,and lung function and a lower risk of behaviour and respiratory problems.Compared with the optimal FGT,early decelerating and late decelerating FGTs were associated with poor neurodevelopment and lung function,while early accelerating FGT was associated with more severe autistic symptoms,poor lung function,and increased risks of overweight/obesity.Metabolic alterations were enriched in amino acid metabolism for early decelerating and late decelerating FGTs,whereas altered metabolites were enriched in lipid metabolism for early accelerating FGT.Thesefindings suggest that FGTs are predictors of early life development and may indicate intrauterine adaptive metabolism.The discovery of optimal and suboptimal FGTs provides potential clues for the early identification and intervention of fetal origin dysplasia or disease,but further research on related mechanisms is still needed.展开更多
目的分析0~3岁儿童年龄别体质指数Z评分(body mass index for age Z score,BAZ)的轨迹,并探讨孕期体重增长水平与儿童BAZ轨迹的关联。方法基于前瞻性队列研究,于2013年至2017年在江苏太仓地区招募孕早期孕妇作为研究对象,追踪其孕期体...目的分析0~3岁儿童年龄别体质指数Z评分(body mass index for age Z score,BAZ)的轨迹,并探讨孕期体重增长水平与儿童BAZ轨迹的关联。方法基于前瞻性队列研究,于2013年至2017年在江苏太仓地区招募孕早期孕妇作为研究对象,追踪其孕期体重变化,采用中国标准计算和评价孕期体重增长(孕期体重增长适宜、不足或过多)。测量儿童出生、1、3、6、8、12、18、24、30和36月龄时的身高/身长和体重,并计算各年龄的BAZ分值。采用基于组的轨迹模型拟合儿童BAZ轨迹。运用多水平Logistic回归分析孕期体重增长水平与BAZ轨迹之间的关联,并调整相关影响因素对结果的影响。结果1864对母婴数据被纳入分析,其中0~3岁儿童的BAZ可拟合为3组轨迹:生长较缓组(34.07%)、生长适宜组(48.23%)和生长快速组(17.70%)。单因素分析显示,以孕期体重增长适宜的母亲为对照组,孕期体重增长不足会增加子代生长较缓的风险(OR=1.95,95%CI 1.28~2.96),孕期体重增长过多可增加子代生长快速的风险(OR=1.57,95%CI 1.19~2.07);多因素分析中调整了母亲孕前体质指数、产次、儿童性别及出生体重后,孕期体重增长不足的母亲其子代生长较缓的风险更高(OR=1.84,95%CI 1.19~2.84);而孕期体重增长过多与儿童早期生长轨迹间关联无统计学意义(OR=1.26,95%CI 0.94~1.68)。结论0~3岁儿童BAZ轨迹可分为生长较缓组、生长适宜组及生长快速组;母亲孕期体重增长不足可增加0~3岁儿童生长较缓的风险。展开更多
目的:探讨我国先天性心脏病(congenital heart disease,CHD)患儿术前至术后3年的生长轨迹,并评估不同CHD类型及术前是否合并营养不良对术后生长轨迹的影响。方法:通过前瞻性队列观察性研究,分析2018年1月至2020年1月广州医科大学附属妇...目的:探讨我国先天性心脏病(congenital heart disease,CHD)患儿术前至术后3年的生长轨迹,并评估不同CHD类型及术前是否合并营养不良对术后生长轨迹的影响。方法:通过前瞻性队列观察性研究,分析2018年1月至2020年1月广州医科大学附属妇女儿童医疗中心385例CHD婴儿术后营养队列数据,根据CHD的不同类型和术前营养状况,分为单纯CHD组和复杂CHD组、紫绀CHD组和非紫绀CHD组以及营养不良组和非营养不良组。所有患儿均规律随访至术后3年。采用混合效应线性回归方法分别比较两组患儿的年龄别体重Z值(weight-for-age Z score,WAZ)、年龄别身高Z值(height-for-age Z score,HAZ)术前至术后3年内的生长轨迹。结果:385例CHD患儿中,简单CHD为43.7%(168/385),复杂CHD为56.3%(217/385);紫绀CHD占35.1%(135/385),非紫绀CHD占64.9%(250/385);营养不良占41.0%(158/385),非营养不良占59.0%(227/385)。出院时及术后1个月患儿总体WAZ较术前有明显下降,营养不良组及复杂CHD组下降更明显。术后1个月WAZ逐渐回升,术后3~6个月呈快速生长追赶状态,术后2年、3年WAZ趋于平缓。营养不良组较非营养不良组WAZ增长速度更慢,差异有统计学意义(P<0.001),复杂CHD组较简单CHD组WAZ增长速度更慢,差异有统计学意义(P<0.001),而紫绀CHD组与非紫绀CHD组WAZ差异无统计学意义(P>0.05)。HAZ在术后3个月至1年内逐渐增长,术后1~3年增长速率较1年内减慢,营养不良组及复杂CHD组HAZ增长速率较慢,差异有统计学意义(P<0.001),而紫绀和非紫绀CHD组差异无统计学意义(P>0.05)。结论:与简单CHD和术前非营养不良的CHD患儿相比,复杂CHD及术前营养不良的患儿生长追赶较慢。疾病类型和术前营养状态协同影响CHD婴儿术后生长轨迹。展开更多
Background Increasing resilience is a priority in modern pig breeding.Recent research shows that general resilience can be quantified via variability in longitudinal data.The collection of such longitudinal data on we...Background Increasing resilience is a priority in modern pig breeding.Recent research shows that general resilience can be quantified via variability in longitudinal data.The collection of such longitudinal data on weight,feed intake and feeding behaviour in pigs has been facilitated by the development of technologies such as automated feeding stations.The goal of this study was to investigate resilience traits,which were estimated as deviations from longitudinal weight,feed intake and feeding behaviour data during the finishing phase.A dataset with 324,207 records between the age of 95 and 155 days on 5,939 Pietrain pigs with known pedigree and genomic information was used.We provided guidelines for a rigid quality control of longitudinal body weight data,as we found that outliers can significantly affect results.Gompertz growth curve analysis,linear modelling and trajectory analyses were used for quantifying resilience traits.Results To our knowledge,this is the first study comparing resilience traits from longitudinal body weight,feed intake and feeding behaviour data in pigs.We demonstrated that the resilience traits are lowly to moderately heritable for deviations in body weight(h2=2.9%–20.2%),in feed intake(9.4%–23.3%)and in feeding behaviour(16.2%–28.3%).Additionally,these traits have good predictive abilities in cross-validation analyses.Deviations in individual body weight and feed intake trajectories are highly correlated(rg=0.78)with low to moderate favourable genetic correlations with feed conversion ratio(rg=0.39–0.49).Lastly,we showed that some resilience traits,such as the natural logarithm of variances of observed versus predicted body weights(lnvarweight),are more robust to lower observation frequencies and are repeatable over three different time periods of the finishing phase.Conclusions Our results will help future studies investigating resilience traits and resilience-related traits.Moreover,our study provides first results on standardization of quality control and efficient data samp展开更多
文摘追踪研究当中,交叉滞后模型可以探究多变量之间往复式影响,潜增长模型可以探究个体增长趋势。对两类模型进行整合,例如同时关注往复式影响与个体增长趋势,同时可以定义测量误差、随机截距等变异成分,衍生出随机截距交叉滞后模型、特质−状态−误差模型、自回归潜增长模型、结构化残差潜增长模型等。以交叉滞后模型和潜增长模型分别作为基础模型,从个体间/个体内变异分解的角度对上述各类模型梳理,整合出此类模型的分析框架,并拓展建立“因子结构化潜增长模型(factor latent curve model with structured reciprocals)”作为统合框架。通过实证研究(早期儿童的追踪研究−幼儿园版,ECLS-K),建立21049名儿童的阅读和数学能力的往复式影响与增长趋势。研究发现,分离了稳定特质的模型拟合最优。研究也对模型建模思路和模型选择提供了建议。
基金Projects(52004182,51804110,51904101)supported by the National Natural Science Foundation of ChinaProject(2020JJ5188)supported by the Natural Science Foundation of Hunan Province,China。
文摘The asymmetric semi-circular bend(ASCB)specimen has been proposed to investigate the cracking behavior in different geo and construction materials and attracted the attention of researchers due to its advantages.However,there are few studies on the fracture toughness determination of rock materials.In this work,a series of fracture tests were performed with the ASCB specimens made of granite.The onset of fracture,crack initiation angle and crack propagating trajectory was analyzed in detail combined with several mixed mode fracture criteria.The influence of the crack length on the mode Ⅰ/Ⅱ fracture toughness was studied.A comparison between the fracture toughness ratios predicted by varying criteria and experimental results was conducted.The relationship between experimentally determined crack initiation angles and curves of the generalized maximum tangential stress(GMTS)criterion was obtained.The fracture process of the specimen was recorded with the high-speed camera.The shortcomings of the ASCB specimens for the fracture toughness determination of rock materials were discussed.The results may provide a reference for analysis of mixed mode I and II fracture behavior of brittle materials.
基金supported by the National Natural Science Foundation of China(U21A20397,22236001,42277428)the Program for HUST Academic Frontier Youth Team(2018QYTD12).
文摘This study aimed to investigate whether fetal growth trajectories(FGTs)could predict early childhood development,indicate intrauterine metabolic changes,and explore potential optimal and suboptimal FGTs.FGTs were developed by using an unsupervised machine-learning approach.Children’s neurodevelopment,anthropometry,and respiratory outcomes in thefirst 6 years of life were assessed at different ages.In a subgroup of participants,we conducted a metabolomics analysis of cord blood to reveal the metabolic features of FGTs.We identified 6 FGTs:early decelerating,early decelerating with late catch-up growth,early accelerating,early accelerating with late medium growth,late decelerating,and late accelerating.The early accelerating with late medium growth pattern might be the optimal FGT due to its associations with better psychomotor development,mental development,intelligence quotient,and lung function and a lower risk of behaviour and respiratory problems.Compared with the optimal FGT,early decelerating and late decelerating FGTs were associated with poor neurodevelopment and lung function,while early accelerating FGT was associated with more severe autistic symptoms,poor lung function,and increased risks of overweight/obesity.Metabolic alterations were enriched in amino acid metabolism for early decelerating and late decelerating FGTs,whereas altered metabolites were enriched in lipid metabolism for early accelerating FGT.Thesefindings suggest that FGTs are predictors of early life development and may indicate intrauterine adaptive metabolism.The discovery of optimal and suboptimal FGTs provides potential clues for the early identification and intervention of fetal origin dysplasia or disease,but further research on related mechanisms is still needed.
文摘目的分析0~3岁儿童年龄别体质指数Z评分(body mass index for age Z score,BAZ)的轨迹,并探讨孕期体重增长水平与儿童BAZ轨迹的关联。方法基于前瞻性队列研究,于2013年至2017年在江苏太仓地区招募孕早期孕妇作为研究对象,追踪其孕期体重变化,采用中国标准计算和评价孕期体重增长(孕期体重增长适宜、不足或过多)。测量儿童出生、1、3、6、8、12、18、24、30和36月龄时的身高/身长和体重,并计算各年龄的BAZ分值。采用基于组的轨迹模型拟合儿童BAZ轨迹。运用多水平Logistic回归分析孕期体重增长水平与BAZ轨迹之间的关联,并调整相关影响因素对结果的影响。结果1864对母婴数据被纳入分析,其中0~3岁儿童的BAZ可拟合为3组轨迹:生长较缓组(34.07%)、生长适宜组(48.23%)和生长快速组(17.70%)。单因素分析显示,以孕期体重增长适宜的母亲为对照组,孕期体重增长不足会增加子代生长较缓的风险(OR=1.95,95%CI 1.28~2.96),孕期体重增长过多可增加子代生长快速的风险(OR=1.57,95%CI 1.19~2.07);多因素分析中调整了母亲孕前体质指数、产次、儿童性别及出生体重后,孕期体重增长不足的母亲其子代生长较缓的风险更高(OR=1.84,95%CI 1.19~2.84);而孕期体重增长过多与儿童早期生长轨迹间关联无统计学意义(OR=1.26,95%CI 0.94~1.68)。结论0~3岁儿童BAZ轨迹可分为生长较缓组、生长适宜组及生长快速组;母亲孕期体重增长不足可增加0~3岁儿童生长较缓的风险。
文摘目的:探讨我国先天性心脏病(congenital heart disease,CHD)患儿术前至术后3年的生长轨迹,并评估不同CHD类型及术前是否合并营养不良对术后生长轨迹的影响。方法:通过前瞻性队列观察性研究,分析2018年1月至2020年1月广州医科大学附属妇女儿童医疗中心385例CHD婴儿术后营养队列数据,根据CHD的不同类型和术前营养状况,分为单纯CHD组和复杂CHD组、紫绀CHD组和非紫绀CHD组以及营养不良组和非营养不良组。所有患儿均规律随访至术后3年。采用混合效应线性回归方法分别比较两组患儿的年龄别体重Z值(weight-for-age Z score,WAZ)、年龄别身高Z值(height-for-age Z score,HAZ)术前至术后3年内的生长轨迹。结果:385例CHD患儿中,简单CHD为43.7%(168/385),复杂CHD为56.3%(217/385);紫绀CHD占35.1%(135/385),非紫绀CHD占64.9%(250/385);营养不良占41.0%(158/385),非营养不良占59.0%(227/385)。出院时及术后1个月患儿总体WAZ较术前有明显下降,营养不良组及复杂CHD组下降更明显。术后1个月WAZ逐渐回升,术后3~6个月呈快速生长追赶状态,术后2年、3年WAZ趋于平缓。营养不良组较非营养不良组WAZ增长速度更慢,差异有统计学意义(P<0.001),复杂CHD组较简单CHD组WAZ增长速度更慢,差异有统计学意义(P<0.001),而紫绀CHD组与非紫绀CHD组WAZ差异无统计学意义(P>0.05)。HAZ在术后3个月至1年内逐渐增长,术后1~3年增长速率较1年内减慢,营养不良组及复杂CHD组HAZ增长速率较慢,差异有统计学意义(P<0.001),而紫绀和非紫绀CHD组差异无统计学意义(P>0.05)。结论:与简单CHD和术前非营养不良的CHD患儿相比,复杂CHD及术前营养不良的患儿生长追赶较慢。疾病类型和术前营养状态协同影响CHD婴儿术后生长轨迹。
基金This study was partially funded by an FR PhD fellowship(1104320N,WG)two SB PhD fellowships(1S05818N(CW)and 1S37119N(RM))of the Research Foundation Flanders(FWO)+1 种基金Moreover,RM and LC were also partly funded by a KU Leuven C2 project(C24/18/036)KH was funded by the UNIPIG project of VLAIO(HBC.2019.2866).
文摘Background Increasing resilience is a priority in modern pig breeding.Recent research shows that general resilience can be quantified via variability in longitudinal data.The collection of such longitudinal data on weight,feed intake and feeding behaviour in pigs has been facilitated by the development of technologies such as automated feeding stations.The goal of this study was to investigate resilience traits,which were estimated as deviations from longitudinal weight,feed intake and feeding behaviour data during the finishing phase.A dataset with 324,207 records between the age of 95 and 155 days on 5,939 Pietrain pigs with known pedigree and genomic information was used.We provided guidelines for a rigid quality control of longitudinal body weight data,as we found that outliers can significantly affect results.Gompertz growth curve analysis,linear modelling and trajectory analyses were used for quantifying resilience traits.Results To our knowledge,this is the first study comparing resilience traits from longitudinal body weight,feed intake and feeding behaviour data in pigs.We demonstrated that the resilience traits are lowly to moderately heritable for deviations in body weight(h2=2.9%–20.2%),in feed intake(9.4%–23.3%)and in feeding behaviour(16.2%–28.3%).Additionally,these traits have good predictive abilities in cross-validation analyses.Deviations in individual body weight and feed intake trajectories are highly correlated(rg=0.78)with low to moderate favourable genetic correlations with feed conversion ratio(rg=0.39–0.49).Lastly,we showed that some resilience traits,such as the natural logarithm of variances of observed versus predicted body weights(lnvarweight),are more robust to lower observation frequencies and are repeatable over three different time periods of the finishing phase.Conclusions Our results will help future studies investigating resilience traits and resilience-related traits.Moreover,our study provides first results on standardization of quality control and efficient data samp
