关于收敛群的几条性质

得到了Ｒ＾ｎ上收敛群中元素的一些性质，利用这些性质证明了收敛群中某些子群的一些极大性质。     

Isolation and Identification of Group I Type 4 Avian Adenovirus and Analysis in Immune Effect of Fiber-2 Protein

The aim of this study was to identify pathogens, which caused pericardial effusion, hepatomegaly and bleeding at a chicken farm in Henan province, and furthermore to analyze effectiveness of immunogenic proteins of the pathogen. This study employed virus isolation, serological assays, PCR and sequencing analysis, animal experimentation, E. coli expression and protein purification, immunogenicity and challenge test and other methods. The results showed that virus was isolated in 7-day-old SPF chicken embryonated eggs, inoculated via the yolk sac route by two blind passages. Viral confirmation was carried out using PCR techniques, and showed a 900-bp-long fragment which shared a 100% homology with the Hexon gene of the serotype C4 strain. Serum neutralization results indicated that this isolate avian adenovirus was the group I type 4 avian adenovirus, named HN-ZK strain. The virus could induce CPE on primary hepatocytes of chicken embryo, and its titer was 10^7.5 TCID₅₀·0.1 mL^-1. Animal experimentation illustrated that the isolated virus caused 100% (10/10) typical symptoms and pathogenicity in 35-day-old SPF chickens. Furthermore, the DNA of the isolate virus was used as a template to express Fiber-2 fragment, with a molecular weight of 33 kDa by using the E. coli expression system, and the protein was concentrated and purified to 300 mg·mL^-1 after centrifugation and purification. SPF chickens were immunized with different doses of the purified Fiber-2 protein, and showed that a dose of 20 μg per chick was completely resistant to challenge of the virulent virus, suggesting the purified Fiber-2 protein has better immunogenicity. This study can provide data for diagnosing the hydropericardium hepatitis syndrome, and developing a genetic engineering subunit vaccine.     

油松毛虫卵（块）和蛹种群简单随机抽样最适样方大小的确定方法

在种群空间格局的研究的基础上，采用７种方法对同松毛虫卵（块）和蛹种群简单随机抽样技术中最适样方大小的确定问题进行了研究，结果表明，无论是卵（块）抑或蛹种群，都是在ｕ＝１时抽样误差最低，即以单株油松为样方时最为适宜，此外，文中还列出了考虑抽样花费时确定最适样方式大小的各种方法，并讨论了有关问题。     

Productivity of different cow genetic groups in dual-purpose cattle production systems in south-eastern Mexico

The objective was to evaluate the effect of cow genetic group, nutritional level and their interaction on some economically important traits of dual-purpose herds managed under field conditions. Nine herds were monitored during a production cycle in Yucatan, Mexico. Herds were grouped into four nutritional levels (NL) based on the metabolizable energy (ME) apparently available on pasture, nutritional management, and milk production. Cows were classified into three genetic groups (GG): low (≤25%), middle (25–75%) and high (≥75%) graded for Bos taurus inheritance. Total milk sold (TMS), days in milk (DIM), TMS adjusted to DIM within each NL (TMSA), body condition score (BCS) at calving, changes of BCS during lactation (CBCS), calf weaning weight (WW), age at weaning (AW), kg of calf weaned per cow (KWC) and calf mortality were studied. The statistical model included the fixed effects of NL, GG, month of calving (MC), parity number (PN) and BCS at calving and GG × NL interaction. The effects of NL, GG, MC, PN and GG × NL were significant (p < 0.05) for TMS, KWC. As expected, TMS increased with NL from 562.4 ± 106 kg for NL1 to 2366.3 ± 100.1 kg for NL4. KWC was greatest for NL2 (138.6 kg) followed by NL1 (135 kg); the lowest KWC corresponded to NL4 (96.0 kg) (p < 0.05). TMS values for the middle (1727 ± 94.7 kg) and the high graded GG (1603.5 ± 83.5 kg) were twice those for the low graded GG cows (828.5 ± 95 kg) (p < 0.05). KWC was also higher for the middle graded group (152.8 kg) than for the low or (104 kg) or the high graded GG (118 kg) (p < 0.05). With better nutrition cows of all GG improved their milk performance but not the calf traits. CBCS was negative for all GG. The highest BCS lost was for cows in NL1 and NL2 and for cows in the high graded GG (p < 0.05).     

Acquisition Model Based on Vague Set for Multi-Atlribute Group Decision-Making

高校图书馆的职能是为师生提供有效的信息以满足教学、科研的需要。图书馆每年纸质图书的采购是一项重要工作,所采购图书的品质直接影响教辅的成效及馆藏的质量。根据各学院教师对图书的各属性评判信息,引入Vague值的一些运算法则及得分函数,在专家权重给定的条件下,建立基于Vague值加权算术平均算子集结的图书优劣排序模型,为新书采购提供有效的参考信息。     

以“科研群体为本”图书馆个性化信息平台服务设计

为科研提供服务是高校图书馆的一项重要职能。针对当前我国高校图书馆在为科研群体服务方面普遍存在的问题,提出了个性化信息平台服务是图书馆在现代信息技术飞速发展的大背景下延伸出的一种新的服务理念和服务方式,通过对国内个性化信息平台服务的调查数据分析,分析了制约地方高校图书馆开展个性化信息平台服务的因素,提出了解决问题的一些见解和方法。     

低温冻害对永定县美蕉生产的影响及预防措施

分析低温冻害对永定县美蕉生产的影响,根据永定县多年的气象资料和美蕉的生长特性,提出美蕉种植区划及预防低温冻害的措施。     

台湾农业产销班的管理模式及启示

在对台湾农业产销班调研的基础上,分析台湾农业产销班的发展背景,从市场营销、生产控制、人力资源、财务管理方面探讨台湾农业企业化管理的主要策略,提出我国大陆发展农民专业合作社发展的对策与建议。     

一类6p2 阶群的非交换图及其对群结构的影响

研究一类固定阶非交换群G的非交换图和其结构之间的一些联系.证明了当p是奇素数,p≠3,且3(p-1)时,11个6p2阶非交换群G中,有5个可由其非交换图刻画,另外6个不能由其非交换图刻画.     

有关p 幂零群的刻画

设A是G的子群,X是G的非空子集.如果A在G中存在补T,使得A与T的每个Sylow子群都X-置换,则称A在G中X-s-半置换.研究X-s-半置换性质对群的结构的影响,并得到有关p-幂零群的一些刻画.