多组离合器参与的换挡过程混合建模与仿真

在分析多组离合器参与的自动变速器换挡过程特点的基础上,指出该换挡过程是由连续系统与离散系统组成的混合系统,进而提出基于键合图理论的连续系统和基于有限状态机的离散系统的换挡过程混合建模方法。在Matlab／Simulink和Matlab／Stateflow平台上建立了包含多种状态的东方红1302R型橡胶履带拖拉机液压机械无级变速器的换挡过程仿真模型,仿真结果表明该建模方法能很好地模拟自动变速器换挡过程中离合器的动态行为,并通过仿真分析了其对换挡品质的影响。     

饲料的不同形态与状态对早期断奶仔猪生产性能的影响

试验采用2×2因子设计,共分4个处理,即粉料和颗粒料2种类型,每种类型2种状态(液态和固态)。试验选用96头(21±1)d断奶的三元(D×L×Y)杂交仔猪,试验期21 d。其中液态料按12∶.5的料水比进行浸泡。试验期间考察仔猪的耗料量、增重、腹泻情况、粪便pH值及木糖吸收情况等,并测定饲料的pH值和淀粉糊化度。结果表明:①与粉料组相比,颗粒料组仔猪平均日增重提高了9.7%(P<0.05),平均日采食量提高了13.5%(P<0.10)。②颗粒料的淀粉糊化度比粉料高15%-16%。③液态组仔猪全期平均日采食量和日增重均高于固态组(P<0.05),分别提高了10.3%和12.9%。④液态料组仔猪血清木糖含量比固态料组高52%(P<0.05),且腹泻程度显著(P<0.05)降低。     

鸡大肠杆菌活的非可培养状态发生相关基因克隆与分析

本研究旨在从分子水平探究细菌活的非可培养状态(VBNC)的发生机制。应用冰乙酸和4℃联合诱导条件,使鸡大肠杆菌进入VBNC状态,并利用mRNA差异显示技术(DDRT-PCR)获得VBNC相关基因。结果表明,从VBNC大肠杆菌中筛选得到的3个差异片段与大肠杆菌23S核糖体RNA基因序列具有较高的核苷酸同源性,分别为98%、98%和99%,而氨基酸的同源性也均在97%以上,表明这3个序列是大肠杆菌23S核糖体rRNA基因的部分序列,同时也是与大肠杆菌VBNC状态发生密切相关的基因。由此推知,当正常大肠杆菌在未暴露任何压力下时,其转录水平较低,特别是23S rRNA的某一(些)基因不显示或受到强烈抑制。当进入VBNC状态后,面临生存压力时,这一(些)基因转录水平明显强于正常状态,而核糖体作为蛋白质合成的主要结构与场所,其某些基因也将积极参与新蛋白质的生物合成。     

五个饲用玉米品种营养成分研究

试验对5个饲用玉米品种（东陵白、中原单32、科多8号、科青1号、科多4号）不同生育期（拔节期、抽穗期、乳熟期）的主要营养物质变化进行了研究,筛选出适宜当地栽培利用的饲用玉米品种并确定最适刈割期。试验结果表明：随着生育期的推进,各品种中粗蛋白、钙、磷、CA显著下降（P〈0.05）,NDF、ADF、OM含量则显著上升（P〈0.05）,各品种在每个生育期内营养物质含量差异不显著;与其它营养物质不同的是WSC含量在抽穗期显著高于拔节期和乳熟期（P〈0.05）。     

Challenges for Multilevel Stakeholder Engagement in Public Trust Resource Governance

The trend in wildlife management over the last two decades has been to develop locally based approaches for responsiveness to local conditions, but some state wildlife agencies are finding the amount of staff time required to service this approach prohibitive. Although local engagement strategies have been lauded as assuring that public trust obligations of state government to citizens are met, we can expect that states with a local focus as their operational level of stakeholder engagement may opt to change their approach to reflect their resource limitations. We argue for comprehensive regional level effort to understand stakeholders augmented with local engagement processes where needed to deal with special circumstances in smaller areas within a region. Such an approach can be anticipated to have implications for stakeholder engagement and human dimensions research needs, which we discuss in the context of public trust resource administration and good governance of wildlife resources.     

香蕉茎叶粉固态发酵条件优化及鹅对其养分利用率的研究

本试验旨在研究应用固态发酵技术改善香蕉茎叶粉养分组成的工艺参数及鹅对其养分的利用率。选择米曲霉和产朊假丝酵母作为发酵菌种,逐步探究5个因素(单菌种发酵、硫酸铵添加量、米曲霉和产朊假丝酵母接种比例、混合菌液接种量)对发酵后香蕉茎叶粉蛋白质含量的影响。利用正交设计筛选最优发酵温度、底物水分和发酵时间的组合。结果显示:米曲霉和产朊假丝酵母单独发酵均能显著或极显著提高发酵后香蕉茎叶粉的粗蛋白质含量(P0.05或P0.01)。添加硫酸铵能显著或极显著提高发酵后香蕉茎叶粉的真蛋白质含量(P0.05或P0.01),其中添加2%硫酸铵组的真蛋白质含量最高。米曲霉∶产朊假丝酵母接种比例为2∶1的处理发酵后香蕉茎叶粉的蛋白质净增加量显著或极显著高于比例为1∶1、1∶3和3∶2的处理(P0.05或P0.01)。正交试验结果显示,以4%的接种量、接种比例为2∶1(米曲霉∶产朊假丝酵母)、2%的硫酸铵添加量,在基质水分为50%,30℃的环境下发酵4 d效果最佳。经过该工艺发酵后的香蕉茎叶粉粗蛋白质含量提高了33.82%,氨基酸分析结果显示,除赖氨酸和精氨酸外其余的15种氨基酸含量均有不同程度的提高。马冈鹅的代谢试验结果显示,发酵后香蕉茎叶粉中的粗蛋白质利用率提高了52.66%,极显著高于发酵前(P0.01);此外,代谢能和能量利用率也都略有提高(P0.05)。由此可见,经过该发酵工艺发酵后的香蕉茎叶粉营养价值不仅得到了改善,也促进了鹅对其养分的消化吸收。     

Morphological variation in the short-tailed fruit bat (Carollia) in Ecuador,with comments on the practical and philosophical aspects of boundaries among species

The mechanisms for the morphological delimitation of species in Carollia remain poorly understood. This is the first study to assess variation in size and shape from strictly geometric terms. Both factors are assessed by statistical perspectives of distribution, overlap and relative distances. Despite its overlap, the size of the skull seems to be the most influential character for the discrimination of species, with shape playing a much smaller role. The smallest species seems to be the most distinct in shape, not only in terms of distance among centroids in morphometric space, but also in the overall trend and direction of variation. Contrary to previous studies, sexual dimorphism is not given by size but by distinct shapes of the skull. Characters such as the shape of the maxilla, previously described qualitatively as discrete with sharp boundaries, appear to be truly continuous with fuzzy borders among species. Because morphometric space is a gamut of continuous variation and overlap, the taxonomic error rate for size characters seems to be substantial for the medium-sized species (Carollia brevicauda Schinz, 1821), with approximately 30–40% of individuals erroneously assigned to a different species after a jackknifed discriminant function. This taxonomic error is higher for shape characters. Morphological, systematic and ecological consequences of the observed patterns of shape and size variation are commented within the context of previously proposed arguments and hypotheses.     

黑曲霉发酵酱油渣的研究

试验研究了黑曲霉的耐盐能力,试验结果表明:NaCl浓度在0-120 g/l以内,黑曲霉生长速率随NaCl浓度的增加先增加后减小,当NaCl浓度为40 g/l时黑曲霉生长速率达到最大值,为2.08 cm/d;并且以酱油渣为试验材料,研究了黑曲霉对酱油渣中粗纤维成分的降解能力,试验结果表明,黑曲霉能高效降解酱渣中半纤维素,30 d降解率达到了84.28%;同时对纤维素和木质素也有一定程度降解,30 d时降解率分别为23.86%和9.43%。本研究结果为酱油渣的饲料化利用提供了必要的数据支持。     

一株乳酸片球菌的筛选、鉴定及其固态发酵饲料原料的产酸分析

本研究从猪的新鲜粪便中分离纯化出一株具有较强产酸效果的乳酸菌HF14,综合形态、生理生化、16SrDNA序列分析,初步鉴定该菌株为乳酸菌片球菌(Pediococcus acidilactici)。对HF14固态发酵豆粕、麸皮、玉米粉与稻壳粉等饲料原料的产酸类别进行分析发现,产生的有机酸以L-乳酸与乙酸为主,其中,发酵玉米粉的pH最低,为3.77,L-乳酸与丙酸含量最高,分别为21.91、1.03mg/g;发酵麸皮的pH降幅最大,丁酸含量最高,为0.72mg/g;发酵稻壳粉的乙酸含量最高,为6.15mg/g,L-乳酸含量最低;发酵豆粕的各个指标居中。     

云南牧草种质资源研究现状及前景

云南省复杂的自然地理和气候条件决定了云南省牧草种质资源的丰富性。为此,介绍了云南省自然条件概况并对云南省牧草种质资源种类的丰富度、分布及研究现状进行了总结,列出了云南草地主要牧草资源植物以及11类草地的草群组成。针对云南省种质资源存在的问题,从保护和利用的目标出发,提出了广泛收集牧草种质资源,对收集到的牧草种质资源进行有效保护和深入研究,积极创新和永续利用的建议和对策,并对牧草种质资源研究的预期目标和前景进行了展望。