蛋鸡髓细胞瘤型白血病的诊断

贵州省开阳县某蛋鸡场进入育成阶段后,鸡群整体消瘦、贫血和发育不良,59 d后开始出现不正常死亡,至71 d时死亡率达1.3%.经流行病学和血清学调查、病理学观察和分子生物学鉴定,确诊鸡群感染J亚群禽白血病病毒并发生髓细胞瘤型禽白血病.调查发现,感染鸡群死淘率显著增加,生产性能严重下降.     

鸡布氏艾美耳球虫致病性研究

用１８日龄公雏作为试验对象,以增重、病变和死亡为判定指标,用Ｅ．ｂｒｕｎｅｔｉ的０．５万／只、１万、５万、１０万、２０万、５０万和１００万／只为接种梯度,研究了布氏艾美耳球虫的致病性。结果表明：接种０．５万／只至２０万／只剂量的Ｅ．ｂｒｕｎｅｔｉ都明显影响鸡的增重;（与对照组相比,均存在极显著性差异（Ｐ＜０．０１）,各剂量组间增重无差异,）５０万／只和１００万／只剂量组的鸡出现减重。５０万／只剂量组鸡死亡５０％,１００万／只剂量组鸡死亡１００％;Ｅ．ｂｒｕｎｅｔｉ接种５万／只剂量组及以上各组鸡饮食欲消失,鸡失去自洁行为,粪量少,含有粘液和血液;剖检病变主要在小肠至直肠,肠壁变薄,易碎,呈粉红色至暗红色,肠粘膜上有小的出血点,肠内容物以粘液和血液为主。部分鸡的盲肠内容物干、呈暗红色。（病变计分为：对照组０分,０．５万／只为０．５７＋;１万／只０．０３＋;５万／只１．１７＋;１０万／只１．５０＋;２０万／只２．２３＋;５０万／只３．６４＋;１００万／只３．８３＋。）１００万／只剂量组中有两只鸡出现腿麻痹症状,不能站立。     

新城疫活疫苗对控制鸡大肠杆菌病的效果观察

为了研究鸡新城疫活疫苗紧急免疫控制鸡大肠杆菌病的效果,通过大肠杆菌人工感染30日龄蛋鸡,待出现病症后,紧急免疫新城疫La-sota弱毒苗(Ⅳ系)4羽份.免疫后5～17 d,通过血凝抑制试验测定血清新城疫抗体水平,试验组新城疫抗体水平逐步提高,对照组抗体略有下降,免疫后17 d两组抗体水平差异显著(P＜0.05);对照组...     

红嘴蓝鹊的巢址选择

2011 ～2013年2～7月,对红嘴蓝鹊（Urocissa erythrorhyncha）的巢址选择进行了研究,结果表明：红嘴蓝鹊营巢最早开始于2月下旬,结束于6月下旬;第一窝出飞后,即开始另选巢址进行第二窝繁殖,原巢不再利用.红嘴蓝鹊营巢于树上,选择2～4月建巢,均为常绿树种;5～6月建巢既有常绿树种,也有落叶树种.巢树平均高度（11.12 ±4.15）m、胸径（26.23±12.85）cm、巢高（7.35±2.80）m （n=13）,主成分分析表明,影响红嘴蓝鹊巢址选择的主要因子有3个,依次为：巢树因子（主要包括：树高、树胸径、巢高）、隐蔽与食物水源因子（巢上郁闭度、巢距最近食源地距离、巢距最近水源距离）、光与人类活动影响因子（巢与巢枝朝向、巢距道路距离）.繁殖期红嘴蓝鹊对人为干扰与噪音敏感,巢位较低和较大的暴风雨等均可能造成红嘴蓝鹊弃巢.     

DNA Immunization Against Very Virulent Infectious Bursal Disease Virus with VP2‐4‐3 Gene and Chicken IL‐6 Gene

The present study was to investigate the feasibility and efficiency of the DNA vaccine to protect chickens against very virulent infectious bursal disease virus (vvIBDV) infection. A plasmid DNA carrying VP2‐4‐3 genes of vvIBDV SH95 and a plasmid DNA carrying chicken interleukin‐6 (ChIL‐6) genes were constructed and designated as pALTER‐MAX‐VP2‐4‐3 and pALTER‐MAX‐ChIL‐6 respectively. Several DNA vaccination experiments were performed: 1‐week‐old chickens were intramuscularly injected with only plasmid pcDNA3‐VP2, pALTER‐MAX‐VP2‐4‐3 or mixture with pALTER‐MAX‐ChIL‐6. The chickens at 4 weeks old were orally inoculated with vvIBDV SH95. The results showed that immunization with the mixture of pALTER‐MAX‐VP2‐4‐3 and pALTER‐MAX‐ChIL‐6 three times conferred protection for 90% of chickens. Enzyme‐linked immunosorbent assay (ELISA) antibody titres in chickens immunized together with pALTER‐MAX‐ChIL‐6 were higher than those immunized simply with plasmid pcDNA3‐VP2 or pALTER‐MAX‐VP2‐4‐3. IBDV was not detected in the bursa of the protected chickens at 8 days after challenge by RT‐PCR. The results indicate that protection against vvIBDV can be achieved by using the VP2‐4‐3 gene of vvIBDV as a DNA vaccine. Furthermore, the simultaneous injection of ChIL‐6 plasmid significantly increased the protection after challenge with the very virulent strain.     

广州市森林公园游客满意度影响因素分析

在借鉴相关研究的基础上,筛选出影响森林公园满意度的关键指标,设计调查问卷。采用分层抽样法对广州市11个森林公园进行调查,以随机方式对游客进行拦截访问,对所获数据进行描述性统计分析、交叉分析、相关性分析和回归分析。结果表明：广州市森林公园的游客满意度主要受管理服务、内部环境、景点项目、游览路线、指示系统、停车设施、可达度、喜爱度、忠诚度等因素的影响,其中环境安静、温湿舒适、停车方便、公交地铁和（高速）公路便利、距常住地距离合意等为核心因素,管理有序、空气清新、植物丰富、景观怡人、购物餐饮租车和卫生小憩设施便利等为重要因素,景点布局新奇、游览路线合理、指示系统清晰等为边缘因素,但影响程度明显分为不同层次,但多数影响因素与游客属性没有显著差异。因此,广州市森林公园建设与管理应坚持以提高游客满意度为抓手,努力实现游客健康休闲环境与设施的供求匹配。     

华北地区夏玉米田马唐治理的生态经济杀除阈期研究

作者于1992～1994年研究夏玉米田马唐(Digitaria sanguinalis L.)治理的生态经济阈期,借助计算机进行数学模拟,建立夏玉米的相对产量与马唐的相对干扰生长时间、相对出苗时间的函数关系。苗后马唐干扰生长的相对时间即相对天数(Xu)与夏玉米相对产量(Yu)的关系式为: Yu=101.5/{1.0 0.01756EXP[—(—0.0876Xu 0.0004888Xu~2)]}…………(1)苗后马唐出苗的相对时间与玉米相对产量的关系式为: Yd=100.73/{1.0 0.96EXP[—(0.06346Xd-0.00006859Xd~2)]}……………(2) 根据生态经济杀除阈期的定义和(1)、(2)两公式计算可知:夏玉米田马唐防除的生态经济杀除阈期的始期应从夏玉米苗后生育期总天数的11.8％开始,结束于夏玉米苗后生育期总天数的53.9％。例如华北地区夏玉米全生育期总天数一般是95天,夏玉米苗后生育期总天数(T)约为88天,故夏玉米田马唐防除的生态经济杀除阈期约在夏玉米苗后10.6—47.5天之间。     

Influence of Ammoniacal Copper Quaternary treatments on mechanical properties of blue-stained Lodgepole Pine wood

Three concentrations （2.8%, 2.0%, 1.2%） of Ammoniacal Copper Quaternary （ACQ） was selected to treat Lodgepole pine wood for evaluating ACQ treatment on mechanical properties of blue-stained wood. The bending modules of elasticity （MOE）, modules of rupture （MOR）, toughness and shearing strength parallel to grain on tangential surface, are tested according to the criteria GB1927-1943-91. Non-treated sample were also tested according to the same procedure. The results showed that the three groups specimen impregnated by different concentrations of ACQ solution met the AWPA standard 2003 of America （UC4A 6.4g/cm^3）. There were significant difference of toughness between treated wood and non-treated wood （p=0.01）, but there were no statistically significant differences among three concentrations in terms of toughness, and toughness of treated wood was approximately 20% lower than non-treated. MOR, MOE as well as sheafing strength parallel to grain were found to be not significantly different between treated wood and non-treated one, and there were no statistically significant difference among three concentrations of ACQ too. Toughness, MOR, MOE and sheafing strength parallel to grain increased with decrease of concentration of ACQ, but they were hardly affected by ACQ preservatives.     

Integrated rice management simultaneously improves rice yield and nitrogen use efficiency in various paddy fields

The hilly area of Southwest China is a typical rice production area which is limited by seasonal droughts and low temperature in the early rice growth period. A field experiment was conducted on three typical paddy fields (low-lying paddy field, medium-elevation paddy field, and upland paddy field) in this region. Nitrogen (N) treatment (180 kg N ha^-1 year^-1) was compared to a control treatment (0 kg N ha^-1 year^-1) to evaluate the effects of integrated rice management (IRM) on rice growth, grain yield, and N utilization. Integrated rice management integrated raised beds containing plastic mulch, furrow irrigation, and triangular transplanting. In comparison to traditional rice management (TRM), IRM promoted rice tiller development, with 7-13 more tillers per cluster at the maximum tillering stage and 1-6 more tillers per cluster at the end of tillering stage. Integrated rice management significantly increased the rice aboveground biomass by 34.4%-109.0% in different growth periods and the aboveground N uptake by 25.3%-159.0%. Number of productive tillers significantly increased by 33.0%, resulting in a 33.0% increase in grain yield and 8.0% improvement of N use efficiency (NUE). Grain yields were significantly increased in all three paddy fields assessed, with IRM being the most important factor for grain yield and productive tiller development. Effects of paddy field type and N level on N uptake by aboveground plants were reflected in the rice reproductive growth period, with the effects of IRM more striking due to the dry climate conditions. In conclusion, IRM simultaneously improved rice yield and NUE, presenting a valuable rice management technique in the paddy fields assessed.     

不同辣椒种质对象耳豆根结线虫的抗性评价

近年来象耳豆根结线虫的危害日益严重.为筛选抗象耳豆根结线虫的辣椒种质,本试验利用种属特异性引物对根结线虫病原物开展分子鉴定,确定为象耳豆根结线虫.接着采用室内人工接种法,对10份一年生辣椒种质和10份中国辣椒种质进行象耳豆根结线虫抗性鉴定,计算根结指数和卵粒指数,并通过比较隶属函数,发现其中3份辣椒种质对象耳豆根结线虫表现为高抗,抗病性最强的是L518M和L525-1M,L42M次之;10份表现为中抗;7份表现为感病,抗病能力最弱的是L69-1M;未发现免疫品种.本研究发现中国辣椒种质的抗病性整体高于一年生辣椒,是重要的抗病种质来源,可用于象耳豆根结线虫抗病育种和后续抗病机理的研究.