不同饲养方式对涪陵水牛生长性能的影响

为了提高涪陵水牛的产肉性能，探索适合涪陵水牛的科学饲养模式，本试验研究了不同饲养方式对涪陵水牛生长性能的影响。挑选3Q头体重接近的涪陵水牛，随机分为A、B、C三组，A组采用栓系舍饲方式、B组则用半天放牧加补饲的方式、C组采取全天放牧加补饲，试验时间为3个月，通过每月末定期测定牛的体斜长、体高、胸围和管围四项指标反映生长发育情况。结果表明，半天放牧组的生长性能明显优于全天放牧组，而舍饲组优于放牧组。     

Expression,purification and activity detemination of recombinant human keratinocyte growth factor in Pichia pastoris

AIM:To determine the conditions of recombinant human keratinocyte growth factor(hKGF) expression for large-scale production using Pichia pastoris(P.pastoris). METHODS:The DNA fragment encoding hKGF mature peptide was artificial synthesized. This artificial gene, which consisted of 20 codons of preference in P. pastoris, was cloned into secretory expression vector pPICZαA and transformed into P. pastoris X-33 strain. Under the optimal conditions in a 5 L fermentor, the target protein was purified using the combination of ultrafiltration and chromatography. The pro-proliferative activity of this protein for rhesus monkey lung epitelial cell line 4MBr-5 was detected by MTT assay. RESULTS:After 60 h of fermentation induced by methanol at 20℃, the expression level of recombinant hKGF was up to 14.1% of the total supernatant proteins. Subsequent filtration through heparin affinity chromatography and Sephadex G-25 yielded 12 mg/L target protein with purity > 95.0%. The glycosylated hKGF stimulated the proliferation of 4MBr-5 cells in vitro and its ED₅₀ was 57μg/L. CONCLUSION:The glycosylated hKGF was successfully expressed using P. pastoris and was able to improve the proliferation of 4MBr-5 cells in vitro.     

东灵山亚高山草甸优势种的点格局分析

点格局分析法是20世纪末发展起来的多尺度空间格局分析方法。通过研究东灵山亚高山草甸种群的点格局,发现草甸种群的空间分布格局和空间关联性同旅游干扰因素有密切联系。在旅游的强干扰下,东灵山亚高山草甸具有集群和各尺度上表现出空间负关联的特点。这种空间分布的特点,说明在旅游干扰严重的群落中,草甸各物种几乎靠顽强的繁殖能力发展起来,生态位差异明显,而后才是物种自身特性、种内和种间竞争等因素作用的结果,因而各种群首先表现出明显的群体效应,以充分利用环境资源。     

江团吉氏柠檬酸杆菌的鉴定及药敏试验

为了研究复方黄芪散对乌骨鸡屠宰性能和肉品质的影响,笔者将500只7日龄乌骨鸡按体重无差异原则平均分为5个处理组,每组100只,A、B、C组在基础日粮中分别添加1.5%(15g/kg)、1%(10 g/kg)、0.5%(5 g/kg)的复方黄芪散(黄芪、苍术、生姜、甘草),D组在基础日粮中添加36 mg/kg的饲用抗生素,对照组E组仅饲喂基础日粮。饲喂至130日龄后,从每个组选取接近平均体重的鸡各10只屠宰,测定屠体率、半净膛率、全净膛率、腿肌率、胸肌率,并测定胸肌pH、剪切力和营养成分。结果表明,复方黄芪散能提高乌骨鸡鸡肉的嫩度及肉品质。     

基于减法模型的非对称包对瓶颈带宽测量方法的仿真实验

TCP/IP网络中,瓶颈带宽是描述路径带宽特征的主要参数。本研究在linux环境下基于减法模型的非对称包对算法(Asymmetric Packet Pair Under Subtraction Module,APP)开发出了测量程序。然后根据实际需要,在NS2环境下证明了对称包序列算法的可靠性。     

我国马流感病毒不同分离株实验感染SPF鸡的研究

本试验分别用马流感病毒吉林株、青海株和北京株人工感染ＳＰＦ鸡，通过ＨＩ价测定、临床观察，病毒分离以及病理观察，证明马流感病毒可在ＳＰＦ鸡体内激发短期的免疫应答，在各实质器官引起轻微的损害，但无明显临床症状，病毒分离阴性。     

A short note on extractive foraging behavior in gray snub‐nosed monkeys

Extractive foraging (EF) involves the exploitation of hidden or embedded foods, generally any food that is not visible to the naked eye. Therefore, EF is particularly important for survival in marginal habitats as it provides seasonal fallback foods in low food availability seasons. Although many studies consider primates’ EF behavior and category, colobine species are usually categorized as non‐extractive foragers and few studies quantitatively examine their EF behavior. In this study, we examined the EF behavior of one colobine species, the gray snub‐nosed monkey (Rhinopithecus brelichi), at Yangaoping in Fanjingshan National Nature Reserve, Guizhou. We recorded 6 categories of EF behaviors. The most frequently sought‐out foods were seeds, young bamboo and invertebrates. Extracted foods accounted for an average of 26.02% of feeding records. As the monkey engages in little EF behavior in the winter when the food availability is low, these results seem to do not support the hypothesis that EF serves to secure additional resources during lean times in marginal or seasonal habitats. According to these findings, we suggest R. brelich should be considered as an extractive forager. Our study also highlights the need for increased representation of colobines in the EF literature to better inform the discussion concerning its link to primate brain evolution.     

台州城市绿心区生态环境建设问题及对策研究

通过对台州城市绿心区建设现状的调查,指出绿心生态环境建设中存在的问题,并提出相应的对策建议:结合台州市的地方特色,保护现有植物资源,丰富植被类型,发展乡土树种,合理运用乔、灌、草、地被结合来美化城市；重视植物造景；重视修复性工程建设；构建可持续发展的生态水景景观；注重人性化设计.     

基于ASP.NET的网上答疑系统的设计与实现

针对传统答疑方式效率低、工作量大等不足,提出了一种基于ASP.NET的网上答疑系统。对网上答疑系统原型进行分析,详细阐述了网上答疑系统的模块和实现过程。实际应用结果表明,该系统不受时间和空间等条件的约束,有效提高答疑效率,并降低了教师工作量,为网络技术在辅助教学中的应用提供了新的思路。