冷风机-风管对南方开放式牛舍的降温效果

为改善南方夏季开放式肉牛舍环境条件,该文设计湿帘冷风机-纤维风管系统,采用风管定点送风、孔口射流高速出风的模式,将冷风均匀送至肉牛活动区域进行局部降温。该研究以栓系饲养西门塔尔牛为试验对象,对环境、肉牛生理及增质量进行测定。结果表明:测定期间,在肉牛站立(1.3 m高度)和躺卧背部高度(0.7 m高度),与对照舍相比,处理舍的平均温度分别降低2.0和1.8℃,平均相对湿度皆增加10%,平均风速分别增加0.69和0.47 m/s(P0.01);试验舍内氨气和二氧化碳平均质量浓度比对照舍分别降低0.17和81 mg/m3,热负荷指数(heat load index,HLI)均值降低2.84(P0.01);试验牛的呼吸频率降低22次/min、直肠温度降低0.35℃、皮温降低1.04℃,差异均极显著(P0.01)。在整个试验期间,处理舍肉牛未出现患病情况,日增质量为0.92 kg/d;对照舍肉牛患病率高达47%,日增质量为0.54 kg/d,差异极显著(P0.01)。该研究表明在开放式牛舍中进行湿帘冷风机-纤维风管局部降温,有助于缓解肉牛热应激,应用于南方夏季高温高湿天气下技术和经济可行。     

树木病虫害防治注射施药技术对树体组织损伤的研究

本文就树干注入农药,对木质部、韧皮部及周皮和整个树体是否产生不良影响做出评价。通过组织切片观察,在木质部部分,注药后与注药前对照比较没有明显的变化。而在韧皮部,注药的部分筛管壁有破损现象,但长期观察整株树体,注药后树体长势良好,不影响树体生长和水分、养分运输。所以,虽有少部分损伤,但无不良影响。本方法可以大规模推广和应用。     

Randomized field trial comparing the efficacy of florfenicol and oxytetracycline in a natural outbreak of calf pneumonia using lung reaeration as a cure criterion

BackgroundRespiratory infections are the main indication for antimicrobial use in calves. Optimal treatment duration currently is unknown, but shorter duration would likely decrease selection for antimicrobial resistance.Hypothesis/ObjectivesDetermine differences in cure rate and healing time between animals treated with florfenicol and oxytetracycline in a natural outbreak of respiratory disease using reaeration observed on thoracic ultrasound examination as healing criterion.AnimalsCommercial farm housing 130, 3 to 9 month old Belgian blue beef calves.MethodsRandomized clinical trial during an outbreak of respiratory disease. Metaphylactic treatment was initiated, randomly treating animals with either florfenicol or oxytetracycline. Ultrasonographic follow‐up was done the first day and every other day for a 14‐day period. At the individual animal level, treatment was discontinued when reaeration of the lungs occurred. Differences in cure rate and healing time were determined.ResultsOf the 130 animals studied, 67.7% developed a lung consolidation ≥0.5 cm. The mean ultrasonographic healing time was 2.5 days in the florfenicol group compared to 3.1 days in the oxytetracycline group (P = .04). After single treatment, 80.6% and 60.3% had no consolidations in the florfenicol and oxytetracycline groups, respectively (P = .01). A Mycoplasma bovis strain was genetically and phenotypically determined to be susceptible to both antimicrobials.Conclusions and Clinical ImportanceUltrasonographic lung reaeration shows potential as a cure criterion to rationalize antimicrobial use for outbreaks of pneumonia. In our study, florfenicol resulted in a faster cure and higher reduction in antimicrobial usage than did oxytetracycline.     

林木抗旱性与其根次生构造关系的研究

按照林木一年生根系的次生构造,特别是根横切面木质部与韧皮部面积之比,导管与木质部面积之比以及导管与根径面积之比,对林木的抗旱性进行综合评价,从遗传特征上揭示各种林木抗旱性的差别。按照这３个指标对８个常见造林树种的抗旱性进行综合评价,从强到弱依次是：刺槐＞旱柳＞紫穗槐＞臭椿＞毛白杨＞白榆＞白蜡＞沙棘。     

秦岭冷杉和巴山冷杉树脂道分布与结构特征的研究

秦岭冷杉和巴山冷杉树脂道的分布与结构特征进行了解剖学研究,结果表明:冷杉树干皮层、枝条皮层、针叶及球果中均有树脂道分布,都能分泌树脂,以树干皮层和针叶中的树脂含量高,具有采集利用价值。     

术后胆管难取性残留结石的治疗

目的：探讨术后肝内外胆管难取性残留结石安全有效的治疗方法。方法：采用碎石、表麻胆管松动结石、水压冲击和结石表面注入H202后经胆道镜取石的方法治疗136例胆道难取性残留结石。结果：136例中，用活检钳碎石83例；用1％利多卡因注入含残石胆管、胆管壁松驰，结石松动套入取石网篮碎石18例；用生理盐水加压冲击胆管使结石松动，再用网蓝碎石19例；注入H202至残石表面，使之腐蚀碎石16例。结论：活检钳碎石，表麻后松驰胆管壁，生理盐水加压冲洗胆管和注入H202至残石表面腐蚀变小，再套入取石网蓝勒夹碎石，是治疗肝内外胆管术后残留难取性结石的较为简便、有效、安全的方法。     

塔里木马鹿原发性肝癌的病理形态学观察

自然患病的塔里木马鹿,表现为食欲不振、消瘦、结膜黄染、腹围增大,对其进行剖检及病理组织学观察,以确定其是否为肝脏方面的疾病。对濒死期的塔里木马鹿剖检,采集肝、心、脾、肺、肾、淋巴结、胃、肠等固定后进行切片,H.E染色后进行病理组织学观察。结果表明,全身渗出液为黄色,肝表面有散在点状出血,质地硬,色淡,有多个散在性灰白色斑块,形状不规则,边缘不十分清楚;病理组织学观察为胆管细胞性肝癌,癌细胞核呈多形性,核仁增大而明显,数量增多,胞浆较少,且多边集;没有发现癌细胞转移。首次发现了塔里木马鹿胆管细胞性肝癌。     

SCINTIGRAPHIC EVALUATION OF THE THORACIC SPINE IN THE ASYMPTOMATIC RIDING HORSE

Scintigraphic evaluation of the spinous processes of the equine spine has been done by subjective evaluation of radiotracer uptake in clinically abnormal horses. To determine the range of variation in asymptomatic riding horses, 33 normal horses were examined. Two 60 degrees oblique views of the thoracic and lumbar spine were evaluated subjectively, and a semi quantitative method based on standardized regions of interest in each spinous process in T10-L3 was also applied. A ratio between each spinous process and a reference area (Rib 15 or 16) was calculated. The effects of two different color displays and a smoothing filter were assessed. The results of the subjective evaluation was compared to the calculated ratios, and the associations between age, gender, weight, height, use and increased radiotracer uptake, and ratios were analyzed. No significant association was found between age, gender, weight, height, use and increased radiotracer uptake, or ratio. One or more areas of increased radiotracer uptake between T13 and T18 were common in the asymptomatic riding horse, which may have implications for the interpretation of clinical patients. The blue, green and red color display had a higher sensitivity for detecting increased radiotracer uptake compared to the continuous grayscale. The smoothing filter used in this study had no effect on the detection of areas with increased radiotracer uptake. The association between the results of the subjective evaluation and the semi quantitative method was apparent when analyzed in T13-17. To evaluate if the semi quantitative method can replace the subjective evaluation, studies on clinically affected horses are necessary.     

不同中心集风管形式对浅圆仓降温通风效果的模拟研究

在CFD数值模拟技术的基础上，对浅圆仓不同中心集风管形式下的径向通风降温数值模拟结果分析，并进行对比以评判优劣。研究的粮食种类为大豆，数值模拟了四种变径形式的中心集风管顶部，或开孔或不流通，共八种情况的通风条件下，粮堆内部温度分布和气流组织情况，将八种情况下的数值模拟结果对比，分析其通风均匀性和通风降温速率。研究发现，集风管高度与粮面平齐且上粗下细时有较为明显的优越性，通风均匀性较好。研究结果对浅圆仓仓储大豆通风降温方式的选择提供了理论依据。     

一次台风过程大气波导特征分析

在介绍大气折射和大气波导类型的基础上,分析了3类大气波导形成的气象条件。以出现在南京地区的大气波导为例,从探空资料、天气图和NCEP再分析资料出发,对受台风影响的大气波导特征进行了综合分析;对湿度场和散度场分析表明,湿度递减以及辐散下沉运动是大气波导发生的主要原因。