Agreement between two inertial sensor gait analysis systems for lameness examinations in horses

Gait analysis is gaining popularity for quantification of lameness and 2 commonly used inertial sensor systems assess trunk movement symmetry: can these be used interchangeably in multi‐centre studies? We compared head and pelvic movement symmetry between 2 inertial sensor gait analysis systems in 13 horses equipped simultaneously with the 2 systems. The first system quantified dorsoventral movement in the local reference frame (System A) and the second system global vertical movement (System B). Widths of limits of agreement were calculated employing a well established regression method dealing with systematically changing differences over the range of measured values. Widths of limits of agreement between Systems A and B were narrower for pelvic movement than head movement. For head movement, they ranged from 6.4 to 6.9 mm for in‐hand trot and from 7.3 to 9.7 mm on the lunge and for pelvic movement from 2.5 to 4.4 mm in‐hand and from 3.6 to 5.3 mm on the lunge. Widths of limits of agreement between the 2 investigated inertial sensor gait analysis systems are of comparable magnitude (some equivalent, some marginally higher) to the currently proposed thresholds of 6 mm for head and 3 mm for pelvic movement used in lameness investigations. Differences in measurements with 2 different systems (A and B) obtained from the same horse falling within the reported values should not be seen as a sign of a change in lameness.     

化隆县草地植被类型及其利用

青海省化隆县地处青藏高原和黄土高原的过渡带,受青藏高原和黄土高原的影响,自然植被与青藏高原上的高寒植被和黄土高原上的植被类型有一定联系,从而形成该区较为复杂的植被类型。据调查,该地区的主要草地植被类型包括荒漠草原、草原、山地灌丛和高寒草甸,并在该地区形成明显的垂直分布。在海拔较低的黄河河谷区分布着与黄土高原相连的植被类型;而海拔较高的山地则分布与青藏高原相连的高寒植被,形成独具特色的植被类型。     

Back kinematics of healthy trotting horses during treadmill versus over ground locomotion

Reasons for performing study: Treadmill locomotion is frequently used for training of sport horses, for diagnostic purposes and for research. Identification of the possible biomechanical differences and similarities between the back movement during treadmill (T) and over ground (O) locomotion is essential for the correct interpretation of research results. Objectives: To compare the kinematics of the thoracolumbar vertebral column in treadmill and over ground locomotion in healthy horses. Methods: Six sound Dutch Warmblood horses trotted on a T and O during 10 s at their own preferred velocity (mean ± s.d. 3.6 ± 0.3 m/s T and 3.6 ± 0.1 m/s O), which was the same in both conditions. Kinematics of the vertebral column was captured by infrared cameras using reflective skin markers attached over the spinous processes of selected vertebrae and other locations. Flexion‐extension and lateral bending range of motion (ROM), angular motion pattern (AMP) and intravertebral pattern symmetry (IVPS) of 5 vertebral angles (T6‐T10‐T13, T10‐T13‐T17, T13‐T17‐L1, T17‐L1‐L3 and L1‐L3‐l5) were calculated. Neck angle, linear and temporal stride parameters and protraction‐retraction angles of the limbs were also calculated. Results: The vertical ROM (flexion‐extension) was similar in both conditions, but the horizontal ROM (lateral bending) of the lumbar angles T17‐L1‐L3 and L1‐L3‐L5 was less during T locomotion (mean ± s.d. difference of 1.8 ± 0.6 and 1.7 ± 0.9°, respectively, P>0.05). During O locomotion, the symmetry pattern of the lumbar vertebral angles was diminished from 0.9 to 0.7 (1 = 100% symmetry) indicating increased irregularity of the movement (P>0.05). No differences were found in the basic linear and temporal stride parameters and neck angle. Potential relevance: Vertebral kinematics during treadmill locomotion is not identical to over ground locomotion, but the differences are minor. During treadmill locomotion lumbar motion is less, and caution should be therefore taken when interpreting lumbar kinematics.     

Analysis of horse movements from non-commercial horse properties in New Zealand

AIMS: To investigate property-level factors associated with the movement of horses from non-commercial horse properties, including the size and location of the property, number and reason for keeping horses.

METHODS: Using a cross-sectional survey 2,912 questionnaires were posted to randomly selected non-commercial horse properties listed in a rural property database. The survey collected information about the number of horses, and reasons for keeping horses on the property, and any movement of horses in the previous 12 months. Three property-level outcomes were investigated; the movement status of the property, the frequency of movement events, and the median distance travelled from a property. Associations were examined using logistic regression and Kruskal-Wallis analysis of variance.

RESULTS: In total 62.0% (488/791) of respondents reported at least one movement event in the year prior to the survey, for a total of 22,050 movement events. The number of movement events from a property varied significantly by the number of horses on the property (p<0.02), while the median distance travelled per property varied significantly by both region (p<0.03) and property size (p<0.01). Region, property size, the number of horses kept, and keeping horses for competition, recreation, racing or as pets were all significantly associated with movement status in the multivariable analyses (p<0.001).

CONCLUSION AND CLINICAL RELEVANCE: This study showed that there are characteristics of non-commercial horse properties that influence movement behaviour. During an exotic disease outbreak the ability to identify properties with these characteristics for targeted control will enhance the effectiveness of control measures.     

天然次生林群落垂直结构的定量研究

本文以三个次生林群落类型为对象,运用相对多度(RA)、相对频度(RF)、相对显著度(RD)及重要值(Ⅳ)等指标,对其垂直结构进行了深入分析,运用填充系数(F)对群落的层次结构研究提供重要依据;在参考多种分层系统的基础上运用动态的分层方法对群落的层次结构进行了较为合理的划分;分析了次生林群落的垂直结构特征对于群落生产力及其动态演替趋势的意义.     

高寒山区地形序列土壤有机碳和无机碳垂直分布特征及其影响因素

地形、生物气候条件具有明显差异的青藏高原约占我国陆地面积的五分之一,开展该地区土壤有机碳和无机碳分布特征的研究对于理解青藏高原土壤碳循环过程与陆地碳库的精确预测以及应对全球气候变化具有重要意义。研究选取位于祁连山中段的阴、阳坡地形序列土壤,分析了不同坡向间以及同一坡向内随海拔高度变化土壤有机碳和无机碳的垂直分布特征及其影响因素。结果表明:阴、阳坡有机碳含量均随土壤深度增加而下降,但阳坡下降的速率(66%~91%)明显高于阴坡(31%~77%);阴坡土壤中碳酸钙基本淋失,通体无机碳含量较低(5.0 g kg-1),阳坡B层土壤无机碳含量是A层的2倍,表现为明显富集。阴坡和阳坡1 m土体总碳密度相当(分别为16.1~33.9 kg m-2和11.8~32.8 kg m-2),其中,阴坡以有机碳为主(占总碳密度的82%~99%),而阳坡有机碳和无机碳密度变化均较大(分别占总碳密度的27%~81%和19%~73%)。因此,坡向是影响高寒山区土壤碳垂直分布和组成的重要因素。此外,降雨量和植被类型对地形序列土壤有机碳和无机碳含量的空间变异也具有重要影响:降雨量每增加1 mm,表层(0~20 cm)土壤有机碳含量增加0.4 g kg-1,而淀积层(40~80 cm)土壤无机碳含量下降0.2 g kg-1;植被类型在一定程度上影响了土壤有机碳的富集程度。本研究揭示了青藏高寒山区土壤碳循环及其碳库预测应充分考虑微地形对坡面尺度下土壤碳垂直分布、碳库组成和空间变异的影响。     

冬小麦叶片氮素时空分布特征及其与籽粒品质的关系

从时间变化、水平和垂直空间分布的角度对冬小麦氮素营养指标进行了分析。结果表明，株型紧凑的普通籽粒蛋白品种“京冬8（JD8）”叶片全氮含量于返青后16 d达最大值，而株型松散的籽粒高蛋白型品种“中优9507（9507）”于返青后8 d达最大值。后期9507叶片全氮含量下降明显，JD8则不同。两品种叶片叶绿素（Chl）含量随时间消     

施用茚虫威饵剂后红火蚁的蚁巢迁移及弃尸行为

红火蚁Solenopsis invicta是典型的社会性昆虫, 在防控过程中容易引起红火蚁巢体迁移和弃尸等现象, 影响防控效果。本研究对标记好的蚁巢施用茚虫威饵剂, 然后定时观察新增加的蚁巢数量和工蚁弃尸量。结果表明, 施用0.08%和0.1%茚虫威饵剂后, 所有处理均有新蚁巢出现, 施药后5~10 d, 新蚁巢大量出现, 随后蚁群趋向稳定, 新增蚁巢减少, 至处理后25~30 d, 再次出现新蚁巢。0.1%茚虫威饵剂15 g/巢处理在施药后5 d出现8个新蚁巢, 药后10 d和30 d分别又新增5个蚁巢, 其他时间新增蚁巢数较少。按处理剂量, 药后30 d, 2种药剂15 g/巢处理出现的新巢数量均显著高于25 g/巢处理。0.1%茚虫威15 g/巢处理, 校正蚁巢累计增加率高达124.98%, 0.08%茚虫威饵剂15 g/巢处理为89.05%; 0.08%和0.1%茚虫威饵剂25 g/巢处理, 校正蚁巢累计增加率分别为12.00%和51.34%。施用15 g/巢饵剂后2 d开始有大量工蚁尸体被丢弃, 至药后4 d弃尸量达最大值, 0.08%和0.1%茚虫威饵剂处理弃尸量分别为330.5头/巢和300.2头/巢, 随后呈逐步下降趋势, 至14 d, 弃尸量降至最低。施药后8 d内弃尸量达总弃尸量75.26%以上, 至药后10 d, 已达总弃尸量的90.08%以上。施用0.08%和0.1%茚虫威饵剂25 g/巢的处理新蚁巢出现较少, 表明施用相对低剂量的饵剂, 更容易引起蚁巢迁移。红火蚁的弃尸行为主要发生在饵剂施用后的前8 d。     

阿尔金山国家级自然保护区的对齿藓属(Didymodon Hedw.)植物调查

在野外调查和采集标本的基础上,对阿尔金山国家级自然保护区对齿藓属植物的分类、区系地理成分和垂直分布进行研究。结果表明:该保护区的对齿藓属植物共计19种,共发现新疆新记录种7种。从种的区系地理成分水平上将其可划分为世界广布成分、北温带成分(占比38%)、旧世界温带成分(占比11%)、东亚-北美间断分布成分(占比27%)、中国特有成分(占比22%),表现出明显的北温带和东亚-北美间断分布成分,并且中国特有成分占有重要地位;垂直分布可划分为高山荒漠带(10种)、山地荒漠带(11种)、高寒草原带(12种)、高山草甸带(4种)、高山稀疏植被带(1种)。文中对该保护区对齿藓属植物的形态特征及其在该保护区的分布进行了描述,并编制了该保护区对齿藓属植物的分种检索表。     

基于视频跟踪的竖缝式鱼道内鱼类运动行为分析

鱼类运动行为的观察能够为鱼类健康监控提供直观信息,而通过人工标定的方式监测鱼群运动行为耗时长、效率低。文章针对鱼类运动行为的监测问题,提出一种基于图像处理技术的罗非鱼运动监测方法。首先利用计算机、CCD高清摄像机获取鱼群运动视频,再对图像进行滤波去噪、灰度等处理;通过Ostu阈值分割法改进Canny边缘检测算法提取鱼群的边缘轮廓;在建立鱼群运动模型的基础上结合目标关联匹配算法,实现罗非鱼运动行为的跟踪和监测。结果显示鱼群的个体检出率为98.96%,轨迹完整度为97%。提出的算法比卡尔曼滤波的轨迹跟踪监测效果略有提升,能够较好地完成鱼群的运动跟踪和动态监测。