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221.
Regular monitoring of movement asymmetry with inertial measurement units (IMUs) to aid in the diagnosis of the underlying cause of a lameness is feasible. Normal ranges for specific groups of horses may be required, with consideration of expert veterinary opinions for both asymmetry screening and lameness assessment. The aim of this study was to determine movement asymmetry values compared with expert lameness scores to enable screening for lameness in Thoroughbreds in race training. IMU gait assessment during in-hand trot-up was performed in 25 racehorses undergoing routine gait analysis or lameness examination at the Singapore Turf Club. Video recordings were graded numerically (0–5) for lameness by six experienced racehorse veterinarians. Inter-observer agreement and consistency were determined. Median lameness scores were used to calculate sensitivity and specificity for head, withers and pelvic movement asymmetry. Guideline values for aligning movement asymmetry values with expert opinions about forelimb and hindlimb lameness were determined from receiver operating characteristics (ROC). Inter-observer agreement was poor to fair, inter-observer consistency was good (intraclass correlation coefficient: 0.667 for forelimbs and 0.617 for hindlimbs). ROCs indicated higher discriminative power for hindlimb lameness using pelvic asymmetry (90% sensitivity, 93% specificity) compared with forelimb lameness using head asymmetry (69% sensitivity, 89% specificity) or withers asymmetry (44% sensitivity, 89% specificity). When compared to expert lameness scores from videos of a limited number of Thoroughbred racehorses, preliminary guideline values for movement asymmetry screening for forelimb lameness (>|14.5 mm|) and hindlimb lameness (>|7.5 mm|) are higher than previously reported clinical thresholds of >|7 mm| for head movement and >|4 mm| for pelvic movement asymmetry.  相似文献   
222.
The objective of this study was to evaluate the effects of induced drought conditions and phosphorous (P) application on osmotic adjustment as reflected in the accumulation of organic solutes in the leaves of frijolillo. The experiment took place under greenhouse conditions without climate control. Plastic containers were used measuring 20 cm high × 15 cm in diameter. In each container, five plants were evaluated from emergence to vegetative growth phase. Three soil moisture regimes were evaluated (25%, 50%, and 100% of field capacity) combined with four concentrations of phosphorous (0, 50,100 and 150 mg kg?1 of soil). A completely randomized block design with a factorial arrangement of 3×4 with four replications was used. The cellular osmotic adjustment as a response to drought stress in frijolillo was associated with the accumulation of sugars, amino acids and proline in that higher concentrations than the control were measured with moisture at 25%. Concentrations of chlorophyll and carotene increased as soil moisture levels decreased.  相似文献   
223.
Summary Single-stemmed potato plants, cv. Bintje, were grown on a nutrient solution under controlled conditions. They were exposed to a short drought stress, or remained untreated. Short-term changes in tuber volume and in specific leaf weight were measured non-destructively. Tubers from control plants increased rapidly in volume during the night and did not grow, or even shrivelled during the day. Tubers of stressed plants did not show a uniform response; some tubers markedly declined in volume during the day. The patterns of volume increase of stressed plants became erratic after the stress, mainly because some plants never fully recovered. Patterns of diurnal fluctuation in tuber volume were similar to diurnal changes in specific leaf weight; tubers within the same stressed plant sometimes reacted differently. In these cases the effects on the diurnal fluctuation partly reflected the long-term effects, reported in an earlier paper.  相似文献   
224.
In late 2018, the fall armyworm(FAW) Spodoptera frugiperda Smith(Lepidoptera: Noctuidae) made its arrival in China and its populations have since proliferated across most of eastern Asia. While S. frugiperda exhibits a considerable dispersal capacity and engages in long-distance migration, there's only scant information on the species' flight capability. Here, we empirically assessed S. frugiperda flight activity under varying climatic conditions using a flight mill. More specifically, under laboratory conditions, FAW exhibited superior flight performance at 20–25°C and 60–90% relative humidity(RH). When quantifying flight performance over five consecutive nights(i.e., 10 h/night), all flight parameters initially increased and then gradually dropped and FAW adults attained a total flight distance, duration and velocity equal to 63.73 km(48.42–94.12 km)(median, quartile range), 24.12 h(20.87–27.73 h) and 2.73 km h~(–1)(2.13–3.33 km h~(–1)), respectively. Our work constitutes a first comprehensive assessment of S. frugiperda flight performance and provides baseline information for future efforts to forecast spatiotemporal changes in its geographical distribution, movement patterns and invasion trajectories. Such can ultimately permit a timely and targeted deployment of area-wide pest management measures against this newly-invasive pest in China and across eastern Asia.  相似文献   
225.
石砾参数对土壤水流和溶质运移影响研究进展   总被引:3,自引:1,他引:2  
土壤水流和溶质运移一直是土壤学研究的热点,溶质运移理论主要应用于地下水污染、污染物运移、土壤重金属污染研究等方面。溶质主要通过优先流和基质流进行运移,影响溶质运移因素很多,主要包括土壤结构、质地、水力传导率、体积质量、初始含水量、根系、石砾等。石砾作为土壤质地中的一个分级单位,与溶质运移关系较为复杂。本文综合介绍了石砾基本内涵以及石砾对土壤水流和溶质运移影响研究进展;系统阐述了石砾内部参数(石砾覆盖度、含量、粒径、空间异质性等)和外部参数(根石结构、干湿冻融、耕作等),指出目前研究主要量化土壤表面及土壤表层石砾参数对水文效应、土壤侵蚀、入渗以及径流的影响,然而石砾参数对溶质运移影响研究不够系统,石砾参数与溶质运移关系研究尚处于初步阶段,对土壤深层石砾研究缺乏;归纳了石砾参数研究技术手段及模型;探讨了目前石砾参数对土壤水流和溶质运移影响研究存在的问题以及今后研究趋势。  相似文献   
226.
The Komesu underground dam is the first full-scale underground dam constructed to prevent saltwater intrusion in Japan. Although the cutoff wall of the dam effectively reduces the movement of saltwater into the reservoir area, saltwater masses remained behind the dam at the time of its completion, and saltwater can intrude beneath and diffuse through the wall, particularly when the reservoir level is below the sea level because of high pumping levels during the drought years. Therefore, it is necessary to estimate in advance whether the saltwater concentration in the pumped water is likely to exceed or not the permissible salinity level because of an increase in the residual saltwater mass as a result of saltwater intrusion and to take necessary measures to suitably manage the saltwater level behind the dam. To analyze saltwater intrusion, we first selected the optimal program suitable for the analysis of saltwater intrusion. Second, we examined the longitudinal dispersivity and the effect of the cone of depression around the pumping wells. Then we analyzed saltwater intrusion into the reservoir area in detail by using a two-dimensional convective–dispersive analysis. The results of the analysis make it possible to improve management of saltwater in the reservoir area behind the underground dam.  相似文献   
227.
在简单分析地震活动基本规律的基础上,介绍了地震预报的多种常用方法:S波分裂、电磁波异常、次声波异常、地应力异常和地壳形变等,指出地震预报是一个复杂的系统,涉及到多种学科,解决地震预报这个世界难题还需要一个漫长的过程。  相似文献   
228.
We propose a new method for estimating fish density using catches obtained by gillnets of given mesh size. This method builds on work for estimating the number of fish approaching a gillnet by modelling the fish movement that leads to a gillnet encounter. The theoretical framework is developed, and the method is tested on catch data for cod Gadus morhua and Dolly Varden Salvelinus malma to demonstrate how the method can be applied. The method relies on knowledge of geometric properties of the net, and morphological and behavioural properties of the fish, so we explore the sensitivity of the estimates to some of these parameters. Estimates are most sensitive to the morphological parameter of the angle the mouth is open while swimming and largely invariant to estimates of uncertain parameters like maximum number of fish that can be caught by the particular net.  相似文献   
229.
Soybean, caused by the rust fungus Phakopsora pachyrhizi, is the most important foliar pathogen infecting soybean. Historically, the disease was important only in the Eastern Hemisphere, but since 1994 the disease has been reported in many countries in Africa and the Americas. In the U.S.A., soybean rust has been perceived as a threat to soybean production and monitoring of the disease occurs throughout the country where soybean is grown. The objectives of this study were to show conclusive evidence that soybean rust spores can be transported by non-conventional means such as clothing. The implication may affect how researchers approach monitoring this disease in research and sentinel plots.  相似文献   
230.
关于陕西电子农务体系创新的思考   总被引:1,自引:0,他引:1  
电子农务对于农业实现现代化、农民致富、农村繁荣至关重要。在此背景下,本文对陕西电子农务发展的现状、运行机制进行了分析,井进一步对其存在的问题进行了探讨,提出了以市场运作为主、政府引导为辅、多元化投资的电子农务服务创新体系,并对完善创新体系提出了相应的对策和建议。  相似文献   
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