微耕机耕深辅助控制系统的设计和试验研究   总被引：2，自引：0，他引：2  

何家慧  康杰  聂友红  何培祥  李云伍  赵华慧 《农机化研究》2016,(3):119-123

在农业生产中,耕深的稳定性是评价耕作质量的重要指标。为此,结合目前微耕机耕深不稳定的现状,设计了一种耕深辅助控制系统,主要用于辅助控制微耕机的耕作深度,提高微耕机的耕作质量。该系统主要由耕深检测装置、控制装置、执行装置和显示界面组成。检测装置用来间接检测耕深,控制单元对检测到的信号进行分析后控制电机转动,从而间接控制耕深调节阻力杆的上下移动,以实现耕深辅助调节。显示模块用于显示实时耕深,为操作人员提供参考。田间试验结果表明:耕深稳定在120~130mm时的耕深稳定性变异系数为5.82%,满足农艺要求。所提出的耕深测量方法、辅助控制执行装置和显示界面对微耕机设计具有一定的参考意义。  相似文献   

A site index model for lodgepole pine (Pinus contorta Dougl. var. latifolia) in northern Sweden     

Mateusz Liziniewicz  Urban Nilsson  Eric Agestam  Per Magnus Ekö  Björn Elfving 《Scandinavian Journal of Forest Research》2016,31(6):583-591

A model was developed for predicting site index (SI) values and top height growth of lodgepole pine in northern Sweden. Data on 169 experimental plots from 61 experiments were used for model construction. Six dynamic site equations derived using the generalized algebraic difference approach (GADA) were tested. All of the equations estimate height and SI values on the basis of a known height and total age, and are base-age invariant. Unbiased parameter estimates were obtained by non-linear modelling without accounting for autocorrelation of residuals. The special formulation of the Hossfeld model and the GADA-transformed logistic function produced the most reliable SI curves. The Hossfeld model is recommended as it did not produce extreme outlying estimates for young stands. The developed model is polymorphic with variable asymptotes and can predict SI and dominant height growth for lodgepole pine between 20 and 50 years old.  相似文献   

C5a受体颉颃剂及其在动物疾病模型治疗中的研究进展     

张泽英  刘东旭 《中国畜牧兽医》2014,41(2):158-162

C5a受体是人和动物体内补体系统的重要组成部分,与C5a结合后介导了众多生物学效应,参与了许多疾病的发生、发展,并在多种病变中起重要作用,如器官缺血再灌注损伤、急性肺损伤、脓毒血症、类风湿性关节炎、肾小球肾炎等疾病。如何抑制C5a受体的生物活性,从而减轻炎症反应一直是免疫学研究的热点问题。文章着重介绍了C5a受体颉颃剂及其在动物疾病模型治疗中的研究进展。  相似文献   

hrp基因关键调控因子HrpG在水稻白叶枯病菌和条斑病菌中的交叉互补性研究     

熊鹂  刘之洋  邹华松  邹丽芳  陈功友 《植物病理学报》2014,44(4):405-413

 水稻白叶枯病菌(Xanthomonas oryzae pv. oryzae, Xoo)和条斑病菌(X. oryzae pv. oryzicola, Xoc)在非寄主烟草上产生过敏反应(HR)和在寄主水稻上具有致病性,是由hrp致病岛决定的,其中HrpG为关键调控因子。Xoo和Xoc侵染水稻途径和在水稻上产生病害症状的不同,是否与hrpG基因有关,还不清楚。本研究利用反向遗传学方法获得了Xoo和Xoc的hrpG突变体PΔhrpG和RΔhrpG,并用hrpG_Xoo基因和hrpG_Xoc基因分别互补上述2个突变体,获得了相应的互补菌株。致病性测定结果显示,PΔhrpG和RΔhrpG突变体丧失了在水稻上的致病性和在非寄主烟草上产生HR的能力,而hrpG_Xoo基因和hrpG_Xoc基因可分别互补上述突变体至野生型水平。利用GUS报告基因检测基因启动子活性发现,hrpG_Xoo和hrpG_Xoc的启动子活性没有显著差别;RT-PCR和Western杂交结果显示,hrpG基因交叉互补菌株中HrpG调控的下游基因hrpX、hpaR、hrcT、hpa2和hrpD6的表达没有差异,且III型分泌系统分泌蛋白Hpa2的分泌性没有受到影响。这些结果表明,稻黄单胞菌hrpG基因可在Xoo和Xoc中交叉互置,位于其上游和下游的调控途径可能相似,而决定Xoo和Xoc在水稻上的侵染途径以及所致病害症状差异可能与hrpG基因位点无关。  相似文献   

The effect of time‐dependent protein restriction on growth factors,nonspecific immunity,body composition,fatty acids and amino acids in the Siberian sturgeon (Acipenser baerii)          下载免费PDF全文

Rahmat Hosseinpour Aghaei  Abdolmohammad Abedian Kenari  Mohammad Ali Yazdani Sadati  Mohammad Esmaeili 《Aquaculture Research》2018,49(9):3033-3044

The effect of time‐dependent protein restriction (PR) and refeeding were investigated on growth, body composition, fatty acids (FA), amino acids (AA) and nonspecific immune functions in the juvenile Siberian sturgeon (Acipenser baeri; 75 ± 5 g). Test diets included: T1 (control) and T2 fish fed diets containing 400 and 300 g/kg protein respectively during the whole experimental period, T3 (every other day) and T4 (every other week) fish were fed diets containing 300 g/kg protein (PR) and refeeding with diet containing 400 g/kg protein respectively, and T5 fish fed a diet containing 300 g/kg protein for 3 weeks and a diet containing 400 g/kg protein for 5 weeks, were fed to the fish for 56 days by visual satiation. Unlike ration T2 and T5, feeding treatments of T3 and T4 showed an increase in fish growth and body composition (p < 0.05) and they were very close to the control group (p > 0.05). Regarding the fatty acid profile, although the percentage of highly unsaturated fatty acids (HUFA) and polyunsaturated fatty acids (PUFA) declined significantly in the T2 and T5 groups, the saturated fatty acid (SFA) and monounsaturated fatty acids (MUFA) indicated no change among the treatments. In addition, the T2 and T5 groups demonstrated a reduction in essential amino acids (EAA) with a simultaneous increase in nonessential amino acids (NEAAs), which was significant from that of controls and other groups (p < 0.05). In terms of nonspecific immune parameters (serum lysozyme activity and alternate complement activity [ACH50]), treatment 3 has an appropriate result that did not have a significant difference with the control group (p > 0.05), but there was significant difference with other groups (p < 0.05). As a result, the T3 treatment can be used in sturgeon aquaculture practically without any negative impacts on biological or physiological indices.  相似文献   

海洋无脊椎动物补体系统研究进展     

彭茂潇  牛东红  李家乐 《海洋渔业》2016,38(3):320-328

补体系统是先天免疫的重要组成部分,在免疫反应中发挥重要作用。补体的研究可以为海洋无脊椎动物提供病害防治的理论基础。本文介绍了海洋无脊椎动物补体系统中已报道的C1q、MBL、ficolin、MASP、B因子、C3和C6等成分,比较了海洋无脊椎动物补体成分的功能,描述了其补体激活途径和补体系统进化情况。目前,海洋无脊椎动物补体的研究发展很快,揭示可能存在与脊椎动物差异较大的补体系统,但是缺乏系统的基础研究而未能构建起理论模型。  相似文献   

FMMU白化豚鼠与花色豚鼠血清Ig和补体含量及总补体活性比较     

李英  郭桂华  顾为望 《动物医学进展》2003,24(6):91-92

测定比较了 2月龄的封闭群 FMMU白化豚鼠与花色豚鼠的血清免疫球蛋白含量、补体含量及活性。结果表明 :白化豚鼠血清 Ig G含量极显著低于花色豚鼠 ,而 Ig A、Ig M含量显著低于花色豚鼠。白化豚鼠 C3含量极显著低于花色豚鼠 ,C4含量显著低于花色豚鼠。血清总补体活性 ( CH50 )显著低于花色豚鼠。  相似文献   

利用一维代数模型分析微咸水入渗特征   总被引：1，自引：0，他引：1  

吴忠东  王全九 《农业工程学报》2007,23(6):21-26

由于淡水资源短缺,微咸水的开发利用成为缓解农业水资源短缺的重要措施,为了研究微咸水条件下的土壤入渗过程,进行了室内微咸水垂直一维入渗试验,分析了不同矿化度的微咸水累积入渗水量随时间的变化过程,并利用一维代数入渗模型模拟计算了土壤含水率剖面。结果表明：含水率模拟计算结果与实测值相吻合。同时利用一维代数入渗模型和Green-Ampt模型对试验资料进行处理,结果表明两模型均可以比较精确地描述微咸水入渗过程,因此两模型可以互相计算参数,但长历时入渗用Green-Ampt模型计算更加精确。  相似文献   

代数方程求根的一个新的数值解法   总被引：1，自引：0，他引：1  

李同胜  罗蕴玲 《河北农业大学学报》2001,24(1):85-88

通过适当的方法将代数方程的求根问题转化成求矩阵特征根问题，然后求矩特征根的ＱＲ方法给出了一个同时求出代数方程的全部根的方法。  相似文献   

Serological Diagnosis of Classical Swine Fever: A Comparison of a Modified Direct Complement Fixation Test with an Immunofluorescence Plaque Neutralization Test in the Diagnosis of Experimental Subclinical Infection     

M. Eskildsen  E. Overby 《Acta veterinaria Scandinavica》1976,17(2):131

Antibody levels in post-infection sera from a pig inoculated with a low virulent strain of classical swine fever virus (Hannover 62) and in sera from two pigs inoculated with another low virulent strain (Spielbach 66) and from an in-contact pig were assayed by complement fixation and immunofluorescence using classical swine fever virus (ALD strain) and bovine virus diarrhoea virus (UG 59 strain) as antigens. The complement fixation test used was modified by addition of a preparation of porcine Glq to the complement and by mercaptoethanol treatment of the immune serum before use. The mercaptoethanol treatment of the immune serum resulted in complete elimination of a haemolytic prozone often seen with porcine immune sera.In the sera from the inoculated animals complement-fixing antibodies appeared earlier than neutralizing antibodies. A few weeks after inoculation there was a correlation between the presence of complement-fixing and neutralizing antibodies.During the entire observation period of 13 weeks it was not possible to demonstrate complement-fixing or neutralizing antibodies in serum from a pig exposed to infection by contact with the two pigs inoculated with the Spièlbach 66 strain of classical swine fever virus.  相似文献