Methods for measuring N2O flux from water surface and N2O dissolved in water from agricultural land

A new chamber method and a stripping method were developed for field measurements of the rate of N₂O emission from the water surface and for determinations of dissolved N₂O in water from agricultural land.

These methods were used for the measurement of drainage canal water and flooded water of rice fields during the period of June 1982 to January 1983. The results demonstrate that aquatic systems of agricultural land may provide both source and sink for atmospheric N₂O.     

Developmental Responses of Wheat cv. Norin 61 to Fluence Rate of Green Light

Summary

Wheat (Triticum aestivum L. cv. Norin 61) plants were grown under five different photon flux densities obtained by modulating the number of green light-emitting diodes (LEDs) under white fluorescent lamps. The experiment was conducted under continuous irradiation at a constant temperature of 20°C to clarify the developmental responses of wheat to the fluence rate of green light. The higher the photon flux density of green light, the shorter the number of days from emergence to heading. The earliest heading was observed in the plants grown under 496 green LEDs, 32.0 days after emergence. A significant logarithmic function could fit the relationship between the fluence rate of green light and developmental rate. In this report, principal component analysis (PCA) was adopted to analyze the confounding of green light versus photosynthetic photon flux density (PPFD) with 17 developmental and morphological traits. The eigenvalues explained were 5.64, 3.20, and 2.61, respectively, for the first, second and third principal components (PCs). The first PC was assumed as the factor related to the isometric growth, and the third PC was assumed as the factor related to the developmental rate and culm elongation. Therefore, it was supposed that the first and third PCs were affected by the PPFD and the photon flux density of green light, respectively. The results suggested that the fluence rate of green light affects the development of wheat as a signal source. Furthermore, the development of wheat was promoted by the green light independent of PPFD.     

Measurement of enteric methane from ruminants using a hand-held laser methane detector

Abstract

This study investigated the effectiveness of the proprietary laser methane detector (LMD) in enteric methane monitoring from individual dairy cows and sheep. Three experiments were carried out. First, the relationship between LMD and indirect open-circuit respiration calorimetric chamber measurements was tested. Sensitivity and specificity for cows were 95.4% and 96.5%. For sheep, sensitivity was 93.8% and specificity was 78.7%. Second, the effect of cow's activity on enteric methane emissions was investigated. During drinking and feeding, cows produced significantly more (p<0.001) methane emissions than when idle. Third, effect of different micrometeorological factors on LMD measurements under outdoor grazing conditions was investigated. Wind speed, relative humidity, pressure and wind direction relative to methane point-source had significant effect on methane measurements (p<0.001) under outdoor conditions. With further validation, the LMD has potential to provide reliable estimates from ruminants and hence provide a useful technique for on-farm monitoring and decision support for greenhouse gas mitigation strategies.     

Population structure and linkage disequilibrium in diploid and tetraploid potato revealed by genome‐wide high‐density genotyping using the SolCAP SNP array

Genome‐wide association (GWA) mapping in potato requires high‐density genotyping. With the Illumina SolCAP potato single‐nucleotide polymorphism (SNP) array, a first tool for GWA mapping in potato became available. Thirty‐six tetraploid varieties and eight diploid breeding clones were genotyped for 8303 SNPs using this array. The objectives of our study were to examine in this set of germplasm: (i) the degree of polymorphism of the SolCAP SNPs in European germplasm, (ii) the population structure, (iii) temporal trends of genetic diversity and (iv) the genome‐wide extent of linkage disequilibrium (LD). Three‐quarters of the SNPs were polymorphic. In the principal coordinate analysis, a clear separation of tetraploid from diploid genotypes was observed, whereas no distinct subgroups among the tetraploid varieties were detected. The nonlinear trendline of the LD measure vs. the physical map distance decayed within 275 bp to an value of 0.10, indicating that theoretically, about 3 million equally distributed SNPs are required for GWA mapping in this diverse set of germplasm. As the LD decay changes with the population selected for GWA mapping, the number of required markers might be different in other germplasm.     

原核生物硒蛋白的生物合成

硒是包括哺乳动物在内许多生物的必需微量元素,与人类健康密切相关。硒分布的不平衡导致所在地食物中硒含量差异较大,且高硒地区的人易发生硒中毒,而低硒地区的人易硒缺乏。胞内硒酸盐经还原及硒磷酸合成酶的活化,在硒代半胱氨酸合酶(SelA)催化下利用Ser-tRNAUGAsec合成硒代半胱氨酸(selenocysteine,Sec),Sec经tRNAUGAsec特异性的类EF-TU延伸因子SelB整合入蛋白质形成硒蛋白。文中主要概述了原核生物硒酸盐的还原代谢和硒代半胱氨酸的插入机制,并提出了利用硒蛋白的合成机制作为检测硒酸盐含量的思路。     

基于硒蛋白生物合成机制的硒生物检测器

硒是许多生物的必需微量元素,与人类健康关系密切。硒在自然界中分布的不平衡导致不同地区的硒含量差异较大,易引起硒缺乏或者中毒。原核生物的硒代半胱氨酸(Selenocysteine,Sec)及硒蛋白的生物合成途径已较为清楚,此为构建硒酸盐生物检测器,进而补充目前常用硒含量测定方法提供了可能。该研究利用原核载体构建硒代半胱氨酸插入所需茎环结构(Selenocysteine insertion se-quence,SECIS)及其突变载体,通过氨苄青霉素筛选获得高效、高准确率的SECIS,并以此构建GFP超表达载体pSEGFP。通过pSEGFP和pSelABC共转化大肠杆菌BL21(DE3),并进行IPTG诱导表达,测定分析发现胞质蛋白的荧光强度与培养基硒酸盐浓度在一定范围内具有较好的线性关系。此结果表明,试验已初步构建了大肠杆菌硒生物检测器,为利用此方法进一步分析测定环境及生物样品中的硒含量奠定了基础。     

生产效率视域下加工番茄生产要素冗余的区域差异及影响因素

新疆是我国番茄制品生产和出口的重要基地,基于新疆加工番茄主产县域480份农户的调研数据,采用DEA-BCC模型,测算新疆加工番茄主产县域的生产效率,分析加工番茄主产县域的生产要素冗余率,并利用地理探测器模型,揭示影响加工番茄生产效率的关键因子。结果表明：新疆加工番茄主产县域的生产效率存在显著差异,且生产效率均未达到DEA有效水平;其次,加工番茄主产县域的生产要素投入存在不同程度的冗余,种植面积和农业机械投入冗余属于资源利用强度不足型,劳动力、化肥及农药投入冗余属于要素投入过度型;家庭纯收入、户主年龄、户主受教育程度、种植时间和种植面积是生产效率出现县域差异的主要因子,解释力度介于61.4%~65.2%,且因子间相互作用的影响力均高于单独作用的影响力,表明促进县域之间生产要素的合理流动和高效集聚,发挥主产县域的辐射带动作用,可以有效提高加工番茄种植户的生产效率。     

基于GC-MS和电子鼻的面粉中粮虫快速检测方法

储粮害虫会降低粮食及其产品的重量、品质和营养健康指数,并且我国粮虫检测方式仍然以人工检测为主。为满足储粮害虫快速检测的需求,采用气相色谱-质谱联用仪（GC-MS）获得了赤拟谷盗（Tribolium castaneum（Herbst））的主要特定挥发性有机化合物（VOCs）,根据这些化合物的性质筛选出多个金属氧化物气敏传感器,并以传感器阵列为核心开发了储粮害虫电子鼻检测装置。该装置采集了赤拟谷盗、被赤拟谷盗侵染的面粉、被长头谷盗（Latheticus oryzae Waterhouse）侵染的面粉3种实验对象的气味信息,提取每条响应曲线的相对变化值和相对积分值作为原始特征矩阵（10×2）,使用主成分分析（PCA）和偏最小二乘回归算法（PLSR）对原始特征矩阵进行分析,并通过建立回归预测模型,实现了对面粉中赤拟谷盗和长头谷盗虫口密度的预测。优化后的传感器数量由10个减少至8个,赤拟谷盗样品的两个主成分累计的贡献率为79.4%。基于PLSR的预测模型对面粉中赤拟谷盗的数量有很好的预测效果（校正集：相关系数r=0.88,均方根误差为8.09;验证集：r=0.89,均方根误差为7.75）;该预测模型对面粉中长头谷盗的数量也有很好的预测效果（校正集：r=0.94,均方根误差为5.85;验证集：r=0.94,均方根误差为6.08）。研究结果表明：该装置能够满足判别储粮中不同虫口密度样本的基本需要,并且具有可靠的稳定性。     

iSCSI虚拟服务器盘阵在图书馆终端机群中的应用

分析了安庆师范学院图书馆的硬、软件资源,并提出了运用iSCSI技术将普通服务器虚拟成SCSI服务器,运用Software RAID方法将普通硬盘组建成磁盘阵列,在客户服务终端机上调用虚拟SCSI服务器RAID盘阵上的服务程序,从而模拟其在真实SCSI盘阵上的高效运行和存储效果,以提高服务器、终端机群以及维护人员的工作效率,降低维护成本。     

Antiproliferative activity of Saponaria vaccaria constituents and related compounds

Total methanolic extracts of Saponaria vaccaria seed derived from several varieties, as well as various purified components obtained through successive chromatographic separations of total extracts were evaluated for their growth inhibitory activity in WiDr (colon), MDA-MB-231 (breast), NCI-417 (lung) and PC-3 (prostate) human cancer cells as well as the non-tumorigenic fibroblast BJ (CRL-2522) cell line using MTT colorimetric assay. Purified bisdesmosidic saponins segetoside H and I were further examined using microscopy and apoptosis assays. Bisdesmosidic saponins exhibited dose-dependent growth inhibitory and selective apoptosis-inducing activity. Growth inhibitory effects were particularly strong in a breast (MDA-MB-231) and a prostate (PC-3) cancer cell line. Total extracts exhibited a different preference being most active against a colon cancer cell line (WiDr). In a comparison of varieties, all of the total seed extracts exhibited similar dose-dependent activities, but with some variation in potency. Monodesmosidic saponins vaccarosides A and B, phenolic vaccarin, and cyclopeptide segetalin A, co-occurring seed substituents, did not exhibit activity. The non-tumorigenic fibroblast cell line BJ (CRL 2522) was growth inhibited but did not undergo apoptosis when treated with bisdesmosidic saponins at low micromolar concentrations. Saponin-rich extracts from Kochia scoparia seed and Chenopodium quinoa were also evaluated alongside Saponaria saponins but did not exhibit activity. Closely related Quillaja saponins exhibited activity but were less potent.