Methods and Reliability of Tissue Doppler Imaging for Assessment of Left Ventricular Radial Wall Motion in Horses

Background: Noninvasive assessment of left ventricular (LV) function is incompletely studied in horses.
Objectives: The goals of this study were to investigate the feasibility, techniques, and reliability of tissue Doppler imaging (TDI) for characterization of LV radial wall motion in healthy horses.
Animals: Three Standardbreds, 3 Thoroughbreds; age 8–14 years; body weight 517–606 kg.
Methods: Repeated echocardiographic examinations were performed by 2 observers in unsedated horses using TDI. Test reliability was determined by estimating measurement variability, within-day interobserver variability, and between-day interobserver and intraobserver variability of all echocardiographic variables. Variability was expressed as coefficient of variation (CV) and the absolute value below which the difference between 2 measurements will lie with 95% probability.
Results: Assessment of LV radial wall motion by TDI was feasible in all horses. Measurement variabilities were very low (CV < 5%) to low (CV 5–15%) for most variables. Within-day interobserver variability as well as between-day interobserver and intraobserver variabilities were low to moderate (CV 16–25%) for most variables. All pulsed-wave TDI variables of systolic LV function showed very low to low variability, whereas some of the variables of LV diastolic and LA function showed moderate to high (CV > 25%) variability. Pulsed-wave TDI variables appeared more reliable than color TDI variables.
Conclusions and Clinical Importance: Measurement of TDI indices of LV function is feasible and reliable in adult Standardbred and Thoroughbred horses. The clinical relevance of LV function assessment by TDI remains to be determined.     

我国农村消费市场现状及开拓对策研究

就我国农村市场消费需求不足的原因,提出改善农村市场消费不足的措施,如增加农民收入、健全农村的社会保障体系、改善农村的消费环境、加强农村的金融服务体系建设以及对农民进行宣传教育,旨在为农村消费市场的开拓提供参考。     

数据挖掘在教学中的应用

本文将数据挖掘应用到学生成绩分析中,通过用户给定的最小支持度,利用Apriori算法得出频繁项集,结合最小置信度,确定各门课程之间的联系,以达到有针对性地帮助学生顺利完成学业的目的.     

基于条件价值法的黄河上游河道生态系统服务恢复支付评估

采用目前国际上最常用的双边界二分式条件价值法对河道沿岸居民的生态服务恢复支付意愿进行评估,以黄河上游河道为例,进行验证分析,得出居民的最高支付价格为26.4元.模型计算结果具有较窄的置信区间和较精确的点估计,表明其拟合效果好,估值具有很高的精确性和可靠性,适宜于对河道沿岸居民的生态服务恢复支付意愿进行评估.     

Resting and Dobutamine Stress Echocardiographic Factors Associated with the Development of Occult Dilated Cardiomyopathy in Healthy Doberman Pinscher Dogs

In 29 healthy Doberman Pinschers, echocardiographic parameters evaluating systolic and diastolic function were examined prospectively at rest and during dobutamine constant rate infusion (5 μg/kg/minute) to determine if any parameters were associated with the development of occult dilated cardiomyopathy (DCM). A resting echocardiogram was repeated 1 year later to determine which dogs had met our criteria for occult DCM. Six dogs developed occult DCM during the follow-up period. Univariate logistic regression analysis showed that at rest, an increased left ventricular internal dimension in systole (LVID-S) ( P = .02), preejection period (PEP) ( P = .03), ratio of PEP to left ventricular ejection time ( P = .02), and isovolumic relaxation time ( P = .02) were significantly associated with the development of occult DCM. During dobutamine stress echocardiography (DSE), high LVID-S ( P = .02) and systolic wall stress index ( P = .04) and reduced fractional shortening ( P = .02) and ratio of peak early to late diastolic mitral filling velocity (E/A) ( P = .05) were associated with the development of occult DCM. Multiple logistic regression showed that LVID-S ( P = .002) and E/A ( P = .002) measured during dobutamine infusion also were associated with the development of occult DCM. Reclassification based on the DSE data was not significantly different than reclassification based on the resting echocardiographic data. Resting echocardiography and DSE have the potential to be clinically applicable screening tests for very early systolic and diastolic dysfunction in Doberman Pinschers, heralding the onset of occult DCM as it is currently defined.     

刈牧后休闲期对草地牧草生产的影响

通过不同间隔时期对多年生黑麦草、白三叶混播草地牧草产量的监测与分析,得出随着休闲期的增加,青绿物质和死亡物质均呈现上升趋势,在较低和较高草地牧草现存量下都会降低牧草生长率。     

Approximating the degrees of freedom for contrasts of genotypes laid out as subplots in an alpha-design in a split-plot experiment

Alpha‐designs have become popular in cultivar trials. Analysis is based on a mixed model. As a result of imbalance, inference tests require approximate methods. This paper investigates the Type I error control of different Satterthwaite approximations for the denominator degrees of freedom of Wald‐type F‐tests and t‐tests in a two‐factorial alpha‐design with cultivars as the subplot factor and management intensities (fertilization, plant protection) as the main plot factor. Simulation results demonstrate good error control for cultivar comparison at the same intensity, with the need for an approximation which diminishes as the number of cultivars increases. By contrast, a comparison of intensities entails a more substantial departure from the nominal significance level, and this is not entirely offset by any of the approximations. The methods are demonstrated using two real data sets.     

疾病治疗方法疗效的统计分析

本文提出一种新的疗效分析法－加权分析。由于此法吸取了疗效程度差异的信息，因而能更科学，更有效地鉴别各种治疗方法（对同一种疾病）疗效的优劣，本文还提供了衡量疗效的加权均值理论值的点估计和区间估计－即预测疗效的置信区间。