480 healthy 1-day-old male yellow-feathered chickens were selected and assigned randomly into groups A and B,each having 6 pens with 40 birds per pen.The birds in group A were fed with wheatbased diet and group B with...480 healthy 1-day-old male yellow-feathered chickens were selected and assigned randomly into groups A and B,each having 6 pens with 40 birds per pen.The birds in group A were fed with wheatbased diet and group B with wheat-based diet supplemented with xylanase(1.2×l0~4 U/kg diet).On day 16,two birds per replication with average live weight were selected and sacrificed.Tissue samples of jejunum and ileum were collected to detect mRNA expression of cationic amino acid transporters using RT-PCR.The results showed that xylanase significantly increased the abundance of mRNA for rBAT and CAT4 in the intestines of broilers fed with wheat-based diets(P<0.05)and had a tendency to increase the mRNA expression of y^+LAT2 and CAT1 in jejunum(P>0.05),y^+LAT2,CAT1 and CAT4 in ileum(P>0.05).The treatment had no effect on the expression of rBAT mRNA in ileum(P>0.05).展开更多
为满足铁路网区间运输能力可视化决策的需求,以及铁路枢纽紧张区段日常分析要求,基于地理信息系统(GIS,Geographic Information System)、大数据技术,设计了集铁路运行线、经营、客票、货票、计划、统计等多源运输数据信息为一体的铁路...为满足铁路网区间运输能力可视化决策的需求,以及铁路枢纽紧张区段日常分析要求,基于地理信息系统(GIS,Geographic Information System)、大数据技术,设计了集铁路运行线、经营、客票、货票、计划、统计等多源运输数据信息为一体的铁路网能力利用分析系统。提出了面向高速铁路、普速铁路的实际通过能力计算方法,以及融合客/货运密度、客座利用率的计算方法;构建了标准统一的时空信息关联模型,将多源数据信息与GIS数据进行融合,实现了铁路网运输能力的可视化表达、多维统计、智能检索、一省一图、车站到发量分析等功能。试点应用表明,该系统能够显著提升面向铁路网的分析能力,减少数据维护工作量,对改善铁路运输能力提供信息化支撑。展开更多
响应需求的末端配送方案可显著提升顾客满意度,识别并提取末端配送快递三轮车配送停留点特征是分析配送时空分布和动态需求的基础。因此,本文提出结合兴趣点(POI)与停留时长规则的停留点识别方法。首先,利用POI信息和瞬时速度初步筛选...响应需求的末端配送方案可显著提升顾客满意度,识别并提取末端配送快递三轮车配送停留点特征是分析配送时空分布和动态需求的基础。因此,本文提出结合兴趣点(POI)与停留时长规则的停留点识别方法。首先,利用POI信息和瞬时速度初步筛选快递三轮车轨迹数据;然后,引入停留时长阈值作为二次筛选条件;最后,合并临近的聚集点,形成完整的停留点集。采用人工校验识别结果的准确性,并借助熵率法计算停留链的熵率,量化评估不同识别方法的精确度。以苏州市顺丰速运快递网点的快递三轮车配送轨迹数据为实证对象,将所提出的方法与货运卡车停留点识别中常用的基于密度的聚类算法(Density-Based Spatial Clustering of Applications with Noise,DBSCAN)进行对比分析。结果表明,DBSCAN算法易将交通信号灯等待误判为配送停留点,而本文所提出的方法则有效规避了该问题,实现高达98%的精确率和召回率;同时,熵率法的应用进一步验证了所提方法在准确率上的有效性。在此基础上,扩大研究范围并识别配送停留点后,分析快递三轮车的出行链与配送时空分布特征。结果表明,8:00左右的高峰期配送车辆数显著多于16:00左右的高峰期;住宅区为配送热点,车辆数最多,且出行距离和工作时长最长;酒店类配送呈现停留时长较短的特点;此外,停留点空间分布亦揭示了部分配送距离偏远的情况。展开更多
基金supported by National Key Basic Research Development Program 973 of China(No.2004CB117501)National Natural Science Foundation of China(No.30671519)Guangdong Province Scientific Technology Research Project(No.2005B20201016)
文摘480 healthy 1-day-old male yellow-feathered chickens were selected and assigned randomly into groups A and B,each having 6 pens with 40 birds per pen.The birds in group A were fed with wheatbased diet and group B with wheat-based diet supplemented with xylanase(1.2×l0~4 U/kg diet).On day 16,two birds per replication with average live weight were selected and sacrificed.Tissue samples of jejunum and ileum were collected to detect mRNA expression of cationic amino acid transporters using RT-PCR.The results showed that xylanase significantly increased the abundance of mRNA for rBAT and CAT4 in the intestines of broilers fed with wheat-based diets(P<0.05)and had a tendency to increase the mRNA expression of y^+LAT2 and CAT1 in jejunum(P>0.05),y^+LAT2,CAT1 and CAT4 in ileum(P>0.05).The treatment had no effect on the expression of rBAT mRNA in ileum(P>0.05).
文摘为满足铁路网区间运输能力可视化决策的需求,以及铁路枢纽紧张区段日常分析要求,基于地理信息系统(GIS,Geographic Information System)、大数据技术,设计了集铁路运行线、经营、客票、货票、计划、统计等多源运输数据信息为一体的铁路网能力利用分析系统。提出了面向高速铁路、普速铁路的实际通过能力计算方法,以及融合客/货运密度、客座利用率的计算方法;构建了标准统一的时空信息关联模型,将多源数据信息与GIS数据进行融合,实现了铁路网运输能力的可视化表达、多维统计、智能检索、一省一图、车站到发量分析等功能。试点应用表明,该系统能够显著提升面向铁路网的分析能力,减少数据维护工作量,对改善铁路运输能力提供信息化支撑。
文摘响应需求的末端配送方案可显著提升顾客满意度,识别并提取末端配送快递三轮车配送停留点特征是分析配送时空分布和动态需求的基础。因此,本文提出结合兴趣点(POI)与停留时长规则的停留点识别方法。首先,利用POI信息和瞬时速度初步筛选快递三轮车轨迹数据;然后,引入停留时长阈值作为二次筛选条件;最后,合并临近的聚集点,形成完整的停留点集。采用人工校验识别结果的准确性,并借助熵率法计算停留链的熵率,量化评估不同识别方法的精确度。以苏州市顺丰速运快递网点的快递三轮车配送轨迹数据为实证对象,将所提出的方法与货运卡车停留点识别中常用的基于密度的聚类算法(Density-Based Spatial Clustering of Applications with Noise,DBSCAN)进行对比分析。结果表明,DBSCAN算法易将交通信号灯等待误判为配送停留点,而本文所提出的方法则有效规避了该问题,实现高达98%的精确率和召回率;同时,熵率法的应用进一步验证了所提方法在准确率上的有效性。在此基础上,扩大研究范围并识别配送停留点后,分析快递三轮车的出行链与配送时空分布特征。结果表明,8:00左右的高峰期配送车辆数显著多于16:00左右的高峰期;住宅区为配送热点,车辆数最多,且出行距离和工作时长最长;酒店类配送呈现停留时长较短的特点;此外,停留点空间分布亦揭示了部分配送距离偏远的情况。
