鸡脚重性状的全基因组关联分析

鸡(Gallus gallus)脚重性状为鸡产业中的重要经济性状.为了揭示鸡脚重性状的遗传基础,寻找可用于鸡脚改良的分子标记,本研究以核心群京海黄鸡为实验动物,测定其脚重,利用简化基因组测序技术在整个基因组范围内检测与脚重相关的SNPs.共检测到16个与脚重相关的SNPs位点,其中13个集中分布在4号染色体上72.8～77.9 Mb区域;2个SNP位点rs475641139和rs475548810达到5％ Bonferroni全基因组显著水平(P＜5.5E-07),其余位点达到全基因组潜在显著水平(P＜1.1E-05).筛选每个SNP周围1 Mb区域内的基因,共找到9个可能的候选基因,并使用基因本体论(Gene Ontology,GO)数据库对9个候选基因的细胞组分、分子功能和参与的生物学进程进行了分析.结果表明二氢蝶啶还原酶(dihydropteridine deductase,QDPR)基因、LIM域结合蛋白2(LIM domain-binding protein 2,LDB2)基因、类184B家族(family with sequence similarity 184 memberB,FAM184B)基因、复合信号免疫球蛋白J结合蛋白(recombination signal binding protein for immunoglobulin kappa J region,RBPJ)基因、纤维母细胞生长因子结合蛋白2(fibroblast growth factor-binding protein 2,FGFBP2)基因、富亮氨酸重复蛋白5(F-box and leucine-rich repeat protein 5,FBXL5)基因、胆囊收缩素受体A(cholecystokinin receptor type A,CCK1R)基因、肌动蛋白互作蛋白1 (WD repeat containing protein 1,WDR1)基因和类桶状蛋白4(tubby like protein 4,TULP4)9个基因和4号染色体72.8～77.9 Mb区域可能为影响鸡脚重性状的重要候选基因和潜在功能区域.本研究为鸡脚重性状的标记辅助选择提供了理论依据.     

Preparation of Atherosclerosis Model Using Guangxi Bama Mini-pig

The atherosclerosis (AS) model was prepared in Guangxi Bama mini-pig,and the atherosclerosis index (AI) was preliminarily identified in occurrence of AS to provide the basis for the preparation of related models.20 Guangxi Bama mini-pigs were randomly divided into control group and experimental group which were fed with high fat and cholesterol diet to prepare the AS model.Blood biochemical indexes were detected in the process of model preparation and the correlation between AI and the results of vascular slices was analyzed to initially draw up AI of AS.The results of vascular slices showed that the incidence rates of AS of Guangxi Bama mini-pigs in experimental group and control group were 20% and 0,respectively.The association analysis between the results of vascular slices and AI in the pathogenic Guangxi Bama mini-pigs preliminarily suggested that AI was above 3.8 and lasted for more than 3 months during the attack.     

基于TM NDVI的库尔勒市域植被覆盖动态变化

以库尔勒市域为研究区,基于1990、1998、2006和2011共4期TM遥感影像提取归一化植被指数(NDVI),将NDVI结果输入到像元二分模型中计算得到研究区各时期植被覆盖度,然后根据研究需要将植被覆盖度划分为4个等级,最后计算覆盖度差值并结合各级覆盖度转移矩阵和土地利用情况分析了库尔勒市域植被覆盖度动态变化特征。结果表明,在1990、1998、2006和2011年间,库尔勒市域总体植被覆盖情况有所改善,植被恢复改善面积比退化面积多23.8%,其中东南部的扇形绿洲平原植被状况改善明显,北部和南部区域植被有所退化。     

基于CA-Markov模型的甘州区土地利用变化预测分析

研究以张掖市甘州区为例,以黑河流域2000年和张掖市2007年土地利用/土地覆盖(LUCC)数据集的矢量数据、2014年Landsat 8 OLI_TIRS 8月份遥感影像和Google Earth影像为数据源,以Arc GIS10.1、ENVI 4.8和IDRISI 17.00为计算平台,利用CA-Markov模型对2014年土地利用变化进行模拟和预测,并将预测结果与2014年甘州区LUCC解译数据作对比分析,其Kappa系数为87.87%,表明预测与现实一致性较佳。最后对2021年甘州区土地利用分类进行模拟和预测。从预测结果可以看出:2000—2021年间甘州区耕地面积和建设用地面积呈现较快的增长趋势,未利用地面积呈现较快的减少趋势;林地和水域呈现缓慢地增长趋势;草地面积变化较小。简要分析了其变化原因主要归因于政策、社会经济、人口和科学技术几方面。对2021年甘州区土地利用变化的预测研究结果可为该区土地利用合理规划管理及经济发展政策的制定提供科学的决策依据。     

Performance of DSSAT-Nwheat across a wide range of current and future growing conditions

Crop models are widely used in agricultural impact studies. However, many studies have reported large uncertainties from single-model-based simulation analyses, suggesting the need for multi-model simulation capabilities. In this study, the APSIM-Nwheat model was integrated into the Decision Support System for Agro-technology (DSSAT), which already includes two wheat models, to create multi-model simulation capabilities for wheat cropping systems analysis. The new model in DSSAT (DSSAT-Nwheat) was evaluated using more than 1000 observations from field experiments of 65 treatments, which included a wide range of nitrogen fertilizer applications, water supply (irrigation and rainout shelter), planting dates, elevated atmospheric CO₂ concentrations, temperature variations, cultivars, and soil types in diverse climatic regions that represented the main wheat growing areas of the world.DSSAT-Nwheat reproduced the observed grain yields well with an overall root mean square deviation (RMSD) of 0.89 t/ha (13%). Nitrogen applications, water supply, and planting dates had large effects on observed biomass and grain yields, and the model reproduced these crop responses well. Crop total biomass and nitrogen uptake were reproduced well despite relatively poor simulations of observed leaf area measurements during the growing season. The low sensitivity of biomass simulations to poor simulations of leaf area index (LAI) were due to little changes in intercepted solar radiation at LAI >3 and water and nitrogen stress often limiting photosynthesis and growth rather than light interception at low LAI.The responses of DSSAT-Nwheat to temperature variations and elevated atmospheric CO₂ concentrations were close to observed responses. When compared with the two other DSSAT-wheat models (CERES and CROPSIM), these responses were similar, except for the responses to hot environments, due to different approaches in modeling heat stress effects.The comprehensive evaluation of the DSSAT-Nwheat model with field measurements, including a comparison with two other DSSAT-wheat models, created a multi-model simulation platform that allows the quantification of model uncertainties in wheat impact assessments.     

横轴流脱粒分离装置的数学模型的建立与试验

横轴流脱粒分离装置滚筒长度限制了其脱粒分离能力,仅被应用于中小型联合收割机。为研究横轴流脱粒分离装置脱粒滚筒转速、喂入量、脱粒间隙等因素对脱粒分离性能的影响,优化装置结构,利用概率学理论建立了横轴流脱粒分离装置的未脱净率和夹带损失率数学模型。对模型正确性验证试验表明,模型对未脱净率的预测相对误差为8.23%,对夹带损失率的预测相对误差为2.90%。仿真分析和试验表明,该模型可反映籽粒轴向分布和脱粒滚筒转速、喂入量、脱粒间隙等参数对脱粒分离性能的影响。     

高州油茶人工林碳储量分布特征

【目的】探明高州油茶Camellia gauchowensi人工林碳储量及分布特征,并估算评价其固碳效应。【方法】根据样地植株径级分布特征,选取不同径级样株各2～3株,取树叶、树干、树枝、树根、果实、花芽各器官测定生物量和碳含量,并建立各器官生物量模型;在标准地内按"S"形选取8个样点,沿土壤剖面分层采集0～20、20～40、40～60和60～100 cm土层的土壤样品,测定土壤容重与碳含量,计算碳储量。【结果】高州油茶中龄林植株各器官生物量分配比例依次为树干树根树叶树枝果实花芽,各器官生物量均随地径的增大而增大。试验林分总生物量为26.902 t·hm~(-2),树体平均碳质量分数为483.45 g·kg-1。同径级各器官的碳含量不同,其中,果实平均碳含量最高。林地100 cm深土层中,土壤碳含量随着土层深度的增加呈明显递减规律,其中,0～20 cm土层碳含量最高,碳质量分数为26.550 g·kg-1。高州油茶林地总碳储量为144.538 t·hm~(-2),其中,树体碳储量为12.857 t·hm~(-2),占总碳储量的8.90%;林地土壤碳储量为131.681 t·hm~(-2),占总碳储量的91.10%。根据中国生物多样性国情报告编写组数据,碳价格为260.90元·t-1,则本试验高州油茶林的碳汇经济效益约为3.8万元·hm~(-2)。【结论】高州油茶林分碳储量高于广东省经济林平均碳储量,林地土壤碳储量高于广东省平均土壤碳储量,林分总碳储量高于珠三角森林生态系统碳储量,具有较高的生态效益。高州油茶不仅有较好的生产效益,而且具有十分广阔的固碳前景。     

基于模型预测控制的农机主从跟随作业控制方法

针对实际环境中由于农业机械（简称农机）作业过程的作业量以及土壤条件的变化等不确定性因素的影响，导致协同作业跟随农机的行驶工况不稳定、跟随协同作业响应慢、控制困难等问题，在综合考虑不确定性以及响应性能的基础上，提出了一种农机跟随分层控制架构，搭建农机田间作业下的纵向跟随动力学模型，并以间距保持、速度跟随、燃油经济性、加速度跟随性能为目标，进行基于模型预测控制（MPC）算法的上层控制器推导，基于前馈以及PI反馈的控制器作为下层控制，以上层控制器获得的控制加速度为目标，进行力矩（电流）跟踪，在保证抗不确定性以及干扰噪声的同时，提高跟随农机的响应能力。通过Matlab/Simulink仿真和田间试验验证，结果表明，该控制方法可以有效解决农机作业的跟随控制问题，与滑模变结构控制器相比，能够实现稳定跟随行驶，且速度误差和加速度误差更小，速度误差控制在-0.29132~0.18001m/s，加速度误差控制在-0.05678~0.05628m/s2，稳定跟随距离误差为±0.45m，具有良好的跟随效果。     

鸡胚及禽类细胞系在生物医药领域的应用及研究进展

鸡胚因发育过程清楚，长久以来作为基础和应用科学研究领域重要的实验模型，尤其在鸡胚发育早期绒毛尿囊膜阶段，因其血管丰富，是天然的免疫缺陷宿主，是病理学、药理学和肿瘤学等研究领域的理想实验模型。作者简述了发育早期的鸡胚组织结构，并介绍了鸡胚绒毛尿囊膜在肿瘤研究、血管生成、器官移植、烧伤等疾病机理研究中的应用，以及在鸡胚病理模型基础上进行的抗肿瘤药物筛选的应用。重点介绍了鸡胚及禽类细胞系在病毒繁殖和疫苗生产、治疗性蛋白和单抗生产方面的应用研究进展。多种人源病毒、禽源病毒、支原体等可在鸡胚及禽类细胞上增殖，并用于疫苗生产。作者对常用的禽类纤维原细胞和多能干细胞的发展和特点进行了阐述，并总结了商业化的禽类细胞系来源以及部分易感病毒。鸡胚表达系统能够在目的蛋白特定位点产生人源化糖基，减少目的蛋白对人的过敏反应，且禽蛋廉价易得，可作为生产人用单克隆抗体和治疗性蛋白的合适供体。作者介绍了鸡胚及禽类细胞系在生物医药领域应用的最新进展，并对鸡胚作为动物模型在未来的应用进行了展望。     

Typical hydrodynamic models for aquaculture nets: A comparative study under pure current conditions

The net is regarded as the most critical component in marine aquaculture facilities as it is the only barrier which protects the environment from fish escapes. Accurate predictions of the net cage deformation and drag force on the nets are needed, both for ensuring fish welfare and for dimensioning of the mooring system. Thus, an appropriate hydrodynamic model is essential. In practice, two types of hydrodynamic force models, i.e., the Morison type and the Screen type, are commonly used to calculate the hydrodynamic forces on nets. Application of the models depends on the underlying structural model and the availability of data. A systematic review of hydrodynamic models is therefore undertaken to compare the models and various parameterisations, in aid of model selection during the design. In this study, eleven commonly used hydrodynamic models, i.e., five Morison models and six Screen models, are reviewed comprehensively, and implemented into a general finite element (FE) solver for dynamic simulations. Sensitivity studies on different current velocities, inflow angles and solidities of the nets are carried out. Moreover, different wake effects are also considered in numerical simulations. The numerical results from different models are compared against existing experimental data under pure current conditions. Suggestions for selection of suitable hydrodynamic models are provided, based on the model comparison.