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Breit S 《Veterinary journal (London, England : 1997)》2002,164(3):809-223
The incidence of facet aplasia was investigated in three groups of pure-bred dogs. We examined large breeds (Rough Collies, Doberman Pinschers, Rottweilers, Bernese Mountain Dogs, German Shepherd Dogs), chondrodystrophic breeds (Dachshunds, Pekinese dogs), and small breeds (Yorkshire Terriers, Maltese dogs). Uni- or bilateral aplasia of zygapophyseal (facet) joints was exclusively found in juvenile and adult small dogs, in which the incidence of aplasia ranged from between 26% (Th1) and 63% (Th8). There was no evidence that aplasia of zygapophyseal joints increases the risk of developing intervertebral disc disease or deformative spondylosis in small breeds. By applying the findings of previous empirical studies on intervertebral disc geometry and its biomechanical behaviour on the present morphometric results, there was an indication that the intervertebral disc may well compensate for the functional loss of aplastic zygapophyseal joints in small dogs. Biomechanical factors and their potential role as inducing agents of facet aplasia in the pre-diaphragmatic thoracic spine are also discussed. 相似文献
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[目的]对以生态脆弱及半干旱气候为典型特征的寿阳县进行农作物土地适宜性评价,以期为农田的可持续发展提供理论依据。[方法]针对研究区寿阳县的当地作物玉米、小麦、高粱和大麦,通过尺度推绎方法开展了传统及机械种植两种情景下的土地耕作适宜性评价。尺度推绎在一个土地系统中完成,该系统由土地单元、土地面和土地点几级空间系统组成。并通过气候调整指数修正了IAO(意大利海外农业研究所)的土地适宜性评价方法。[结果]4种作物种植适宜性出现了两极化现象:4种作物的最适宜等级(S1)和最不适宜等级(N2)在研究区占大部分地区。玉米、大麦和小麦在传统模式下更适宜耕作。[结论]未来的耕作政策应更加注重在非宜耕区实现耕地向林地与草地的转变,在宜耕区加大农业生产的投入,注意提高牧民生活与环境保护的平衡,以维持一个健康、稳定的生态系统。 相似文献
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边缘提取是遥感数字图像处理的基本工作之一。为此.给出了一种通过图像灰度值来逼近和重构图像的、连续函数的小面模型边缘提取算法.并使用数学形态学的方法对提取的边缘进行了细化。从而得到图像的精确边缘。 相似文献
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Interpretation of cervical radiographs can be challenging due to the complex anatomy and superimposition of osseous structures on either side of the vertebrae. This report describes the investigation of neck pain in a Thoroughbred gelding following a traumatic fall. Several imaging modalities were used to demonstrate the presence of a fracture of the left cranial articular process of the fourth cervical vertebra (C4), including nuclear scintigraphy, ultrasonography, oblique radiographic projections and a novel cineradiographic technique. Oblique radiographs were superior to standard lateral‐lateral radiographs in both the diagnosis and for monitoring the progression of healing of the articular process fracture in this case. 相似文献
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运用流动等值面技术,建立了单纯形算法的现代格式,并讨论了其有关性质,分析了遗失在对偶单纯形算法中的原可行性质,提出了一种可供选择的代数途径.通过适当的代数路径的选择,可以有效避免循环. 相似文献
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Reasons for performing study: Arthrosis of the articular process joints (APJs) in the caudal thoracolumbar region of horses may cause back pain and subsequent reduced performance or lameness. Ultrasound‐guided injections of the APJs of the equine back have been described only briefly in the literature. Objectives: To evaluate factors affecting the accuracy of intra‐articular injections of the APJs in the caudal thoracolumbar region. Methods: One‐hundred‐and‐fifty‐four injections with blue dye were performed on APJs including the T14–L6 region in 12 horses subjected to euthanasia for reasons unrelated to back problems. The backs were subsequently dissected to verify the location of the injectate in relation to the APJs. Results: Twenty‐seven percent of the injections were found to be intra‐articular and a total of 77% found to be within 2 mm of the joint capsule including the intra‐articular deposits. Application of a medial approach and 18 gauge needle were significantly associated with an intra‐articular injection or deposition close to the joint capsule. Operator, APJ (location) and back number (chronological) did not significantly affect the accuracy of injection. Conclusions and potential relevance: Injection of the vertebral APJ in the thoracolumbar region using ultrasound guidance is a reliable method, as most of the injections were either in or within 2 mm of the joint. Based on the findings of this cadaver study, the medial approach is expected to be the most accurate in live horses. Further investigations are required to evaluate the diagnostic and therapeutic potential of this method in clinical practice. 相似文献
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The accuracy of using radiographs to diagnose cervical facet osteoarthritis (CFA) in horses is undetermined. Further investigation is required to determine the clinical significance of radiographic evidence of CFA, the prevalence of radiographic changes in horses without clinical signs, and the long-term efficacy of intra-articular CFA treatment. The objectives of this study is to compare degenerative changes of the cervical facet joints of the cervical vertebrae on radiographs of horses with clinical signs of CFA with healthy cohort-matched horses, to compare clinical findings between groups, and to obtain follow-up information on the long-term outcome in treated horses. This is a retrospective case-control cohort-matched comparison study of horses treated for cervical facet disease versus horses with no clinical signs of cervical facet disease. Horses diagnosed with CFA and treated with intra-articular injection of corticosteroids were included. Follow-up information on recovery from treatment was obtained via telephone survey of owners/trainers. Healthy horses with no clinical signs of CFA were matched to treated horses by breed, sex, age, and sport as the control group. Two blinded radiologists reviewed cervical spine radiographs for each horse and recorded CFA score and intravertebral/intervertebral measurements. Clinical and radiographic parameters were compared between treatment and control groups. There was a significant difference in CFA grades for C5-6 and C6-7 between horses with presence of clinical signs and healthy horses. However, interobserver agreement between radiologists for grading CFA was moderate and only 56% of values were identical for both observers. Atrophy of the neck was present on clinical examination in most cases in the treatment group. Dressage horses were overrepresented. Overall, 64% of horses returned to their previous level of performance after treatment. Clinical examination data collected for the treatment group were retrospective and were obtained by different clinicians. Eight owners/trainers were not able to be reached for the survey. There was a significant difference in CFA grades for C5-6 and C6-7 between horses with presence of clinical signs and healthy horses. Despite these statistical differences, the clinical diagnosis of CFA based on radiographic grading alone is questionable because of the lack of agreement between the radiologists. To strengthen the diagnosis, clinical signs of facet disease, in particular atrophy of the neck muscles, need to be present to make this diagnosis. Intra-articular corticosteroid injection was effective at allowing most treated horses to return to athletic use.. 相似文献
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Aubrey A. Webb DVM John W. Pharr DVM MSc Linda J. Lew DVM MSc Kimberly A. Tryon DVM 《Veterinary radiology & ultrasound》2001,42(1):9-13
Intraspinal cysts of the L6-L7 and L7-S1 articular process joints in a six-year-old neutered female German Shepherd Dog were diagnosed using magnetic resonance (MR) imaging. Histopathology provided a diagnosis of ganglion cysts. Clinical, laboratory, radiographic and MR imaging findings are described. Briefly, radiographic findings revealed lumbarization of the first sacral vertebra, and fusion of the first caudal vertebra to the sacrum. In addition, spondylosis and articular process osteoarthrosis occurred at L6-L7 and L7-S1. MR imaging revealed multiple, well encapsulated structures ranging in size from 3-10 mm in diameter which were found to arise from the L6-L7 and L7-S1 articular process joints. These cysts had signal intensities that varied from hyperintense to the cerebrospinal fluid (CSF) on T1 weighted images to isointense to CSF on T2 weighted images. Decompressive surgery in conjunction with arthrodesis of these joints resulted in resolution of clinical signs. The dog remained pain-free 1 1/2 years following surgical therapy. 相似文献