RCPs气候情景下三江平原典型流域耕地动态模拟

选取三江平原典型流域挠力河流域为研究区,以1990、2002和2014年3期Landsat影像、DEM数据和社会经济统计资料等多源数据为基本信息源,结合3S技术,运用FLUS模型定量模拟代表性浓度路径情景系列(RCPs)下耕地动态变化特征。结果表明:24 a间挠力河流域的旱地面积变化幅度较小,水田面积持续增加,1990—2002年水田扩张剧烈,2002—2014年扩张速度趋于缓和;3个时点的旱地均沿东北-西南轴方向进行分布,主轴沿顺时针缓慢旋转,空间变化稳定,分布范围逐渐减小。水田沿东北-西南走向分布,1990—2002年其主轴逆时针旋转,后顺时针旋转至45.31°,整体分布较为离散,极化特征不明显;通过对比不同空间分辨率及时间尺度下模拟精度,确定最优模拟空间分辨率为200 m,最优模拟时间点为2038年;MESSAGE气候模式下,未来挠力河流域的旱地面积先减少后增加,水田继续维持扩张态势,2029年后面积将以2%速度逐年下降,其分布将更加聚集,主轴沿顺时针旋转,重心逐渐向东北方向进行偏移;AIM气候模式下,气候波动对水田的影响程度大于旱地,旱地面积持续缓慢增加,水田面积在波动中下降,空间分布的极化特征突出。     

我国淡水养殖业发展的空间变化影响因素分析

在陆地农业资源退化和人口总量上升的双重压迫下,淡水养殖有望成为支撑我国居民口粮供给的另一支柱产业。基于2007-2014年我国省域淡水养殖面板数据,探寻了我国淡水养殖区域的格局变化,利用全局Moran’s I指数考察淡水养殖区的空间相关性,并通过构建空间杜宾面板模型分析了产业格局变化的影响因素。研究表明:1我国淡水养殖业呈现出"东南热、西北冷"的特点,省域间的空间相关性逐年显著;2淡水养殖资金投入增加、养殖面积扩大、区域经济发展水平提升会对淡水养殖量有正向的作用,体现我国淡水养殖业由粗放经营向集约化经营的转变;3淡水养殖面积负间接效应反映"过度养殖"和环境污染对淡水资源的破坏会减缓淡水养殖业的发展;4淡水养殖业发展和城镇化的进程之间不矛盾,在未来可以稳定持续地提供淡水产品,成为国家粮食安全和食品安全重要保障。最后从合理规划淡水养殖区域格局、平衡省份间技术推广资金投入和加强对水资源污染的监管3个方面提出了推动淡水养殖业发展的政策建议。     

Sinomenine reduces MPP+-induced damage in SK-N-SH cells via ANRIL/miR-626 signaling pathway

AIM To investigate the effect of sinomenine (SN) on the damage of human neuroblastoma SK-N-SH cells induced by 1-methyl-4-4 phenylpyridine (MPP⁺) and its mechanism for exploring the pathogenesis of Parkinson disease. METHODS SN was used to treat MPP⁺-induced SK-N-SH cells. The levels of malondialdehyde (MDA) and glutathione (GSH) in cell culture supernatants were measured by ELISA. The apoptosis was analyzed by flow cytometry. The protein expression levels of Bcl-2 and Bax were determined by Western blot. The expression levels of long noncoding RNA ANRIL and microRNA-626 (miR-626) were detected by RT-qPCR. Dual-luciferase reporter assay was used to evaluate the relationship between ANRIL and miR-626. After ANRIL small interfering RNA was transfected into SK-N-SH cells, the effects of ANRIL expression knock-down on MPP⁺-induced SK-N-SH cell apoptosis, the protein expression levels of Bcl-2 and Bax, and the levels of MDA and GSH in cell culture supernatants were examined. RESULTS After treatment with MPP⁺, the apoptotic rate, Bax protein level and ANRIL expression in SK-N-SH cells were increased (P<0.05), and the Bcl-2 protein level and miR-626 expression were decreased (P<0.05). The level of MDA in cell culture supernatants was increased (P<0.05), and the level of GSH was decreased (P<0.05). After SN treatment or ANRIL expression knock-down, decreased apoptotic rate, Bax protein level and ANRIL expression (P<0.05), and increased Bcl-2 protein level and miR-626 expression in MPP⁺-induced SK-N-SH cells were observed (P<0.05). The level of MDA in the cell culture supernatants was decreased (P<0.05), and the level of GSH was increased (P<0.05). CONCLUSION SN attenuates MPP⁺-induced damage in SK-N-SH cells by regulating ANRIL/miR-626 signaling pathway.     

氮对低氧胁迫下樱桃根系抗氧化酶活性及线粒体功能的影响

 以‘吉塞拉5号’樱桃组培苗为试材, 研究短期低氧胁迫下氮对樱桃幼苗根系抗氧化酶活性 及线粒体功能的影响。通过溶氧调节仪人为控制营养液溶氧浓度为2 mg·L ^{- 1} , NO₃^- 浓度共设4个水平:0、7.5、15.0、22.5 mmol·L ^{- 1} , 以1 /2 Hoagland营养液正常低氧处理(NO₃^- 浓度7.5 mmol·L ^{- 1} ) 为对照。结果表明: 各处理SOD、POD、CAT酶活性均呈现先升高后降低的趋势。与对照相比, 营养液加氮处理的SOD、POD、CAT酶活性升高, 膜质过氧化程度减轻, 且氮浓度越大酶活性升高幅度越大, 而营养液缺氮处理的酶活性降低, 膜质过氧化程度加重; 营养液缺氮处理樱桃根系线粒体中的H₂O₂和MDA含量、O₂^-·生成速率升高, 而营养液加氮处理可降低O₂^-·的产生及MDA含量, 提高线粒体的氧化磷酸化水平, 保护樱桃根系线粒体膜的完整性, 对线粒体呼吸功能的破坏明显减轻, 且NO₃^- 离子浓度高时效果更好, 说明适当提高营养液中的氮素水平可以缓解低氧胁迫对樱桃根系的伤害。     

Seed yield and water use efficiency of canola (Brassica napus L.) as affected by high temperature stress and supplemental irrigation

The effects of high temperature stress and supplemental irrigation on seed yield and water use efficiency (WUE) of canola (Brassica napus L.) were studied in a field experiment conducted for 2 years. The experiment was a randomized complete block design arranged in split plot, conducted at Agricultural Research Station of Gonbad, Iran. It was arranged in two conditions, i.e. supplemental irrigation and rainfed. Two cultivars of canola (Hyola401 and RGS003) as subplots were grown at five sowing dates as main plots. The sowing dates were 9 November, 6 December, 5 January, 4 February and 6 March in 2005-2006 and 6 November, 6 December, 5 January, 4 February and 6 March in 2006-2007, to have a wide range of environmental conditions around flowering and seed filling periods, and to coincide reproductive stages of the crop with high temperature stress. Seed yield was improved due to field management practices, such as supplemental irrigation and optimum sowing date. Supplemental irrigation was an efficient practice to mitigate water stress, and to increase aboveground dry matter and seed yield. There was a strongly negative relationship between seed yield and air temperature during reproductive stages. Delay in sowing led to more rapid developmental of canola, decreased aboveground dry matter, leaf area index (LAI), harvest index (HI), WUE, and seed yield. Achieving a high aboveground dry matter was an essential prerequisite for high reproductive growth and a high seed yield. Greater seed yield and WUE at first sowing date were associated with greater LAI and aboveground dry matter, and lower temperatures during reproductive stages. The results support the view that WUE can be used as an indirect selection criterion for seed yield in genotypic selection.     

图书馆为建设社会主义新农村提供支持的有效举措——对“村村大学生”服务方式的思考

“村村大学生”培养计划是黑龙江省开展科教兴农工作的重要举措，是建设社会主义新农村的有力保证。文章论述了高等农业院校图书馆应针对该群体深挖服务潜能，拓展服务方式，全方位配合学校培养优秀的“村村大学生”人才，为地区农村的快速发展提供技术支持和人才保障。     

快速成形技术及其在模型制造中的应用

本文介绍了快速成形技术的基本原理,并在分析其制造快速、应用广泛和经济效益突出等特点基础上,给出了快速成形技术在工程结构模型、医学模型和展品及艺术品等模型制造领域中的应用实例。     

铬对热应激肉鸡消化器官的影响

选用处于热应激条件下的24只16日龄科宝(COBB)肉鸡。随机分成试验组Ⅰ、Ⅱ、Ⅲ和对照组。试验组分别添加饲喂10、20、30mg/kg含铬的玉米—豆粕型基础日粮25d。试验结束后,通过对试验组肉鸡消化器官显微组织学观察表明:给热应激下肉鸡补充有机铬,可缓解热应激反应,增强机体免疫功能。     

电动液压助力转向系统对整车操纵稳定性影响分析

对电动液压助力转向系统各部分建立数学模型,基于Matlab软件里的S imu link模块对电动液压助力转向系统模型和四自由度车辆模型所组合的系统模型进行仿真。分析了在不同转向盘角阶跃输入速度、不同车速下的横摆角速度和侧向加速度对汽车操纵稳定性的影响,揭示了转向特性与车速和转向盘角阶跃输入速度的内在关系。     

Prediction of irrigation return flows through a hierarchical modeling approach

The quantity of water available for irrigation is getting scarce in many countries and it assumes great importance for assured crop production, especially in view of the erratic behavior of the monsoon. Thus, there is a pressing need to improve the water efficiency of irrigation systems. One-way of improving the efficiency of the irrigation system is reusing the return flow from the irrigation system. This task requires quantification of return flow, which still remains as a grey area in irrigation water management. The estimation of return flow from the irrigation system is usually obtained using thumb rules depending upon the site-specific conditions like command area conditions and soil properties. In this paper, a hierarchical modeling technique, namely, regression tree is developed for return flow estimation. Regression tree is built through binary recursive partitioning. The effective rainfall, inflow, consumptive water demand, and percolation loss are taken as predictor variables and return flow is treated as the target variable. The applicability of the hierarchical model is demonstrated through a case study of Periyar-Vaigai Irrigation System in Tamil Nadu, India. The model performance shows a good match between the simulated and the field measured return flow values. Results of statistical analysis indicated that the correlation coefficients are high for both single as well as double crop seasons.