Economic impact of Wheat streak mosaic virus in the Texas High Plains

Wheat streak mosaic virus, vectored by the wheat curl mite Aceria tosichella Keifer, is a major limiting factor in wheat production in the Texas Panhandle. It is the most frequently encountered virus in the region, affecting both shoot and root biomass, and consequently it can drastically reduce both forage and grain yield, and water-use efficiency of the plant. In light of the continuing decline of water levels in the Ogallala Aquifer, its effect on water-use efficiency has significant implications for irrigated fields, especially with regard to energy costs for pumping water. This article estimates the potential economic losses from the virus infection. To achieve this objective, partial budgeting techniques, based primarily on data from field experiments, were used. Results indicate that Wheat streak mosaic virus causes grain and forage yield losses that significantly affect profits from wheat production. In addition, irrigated wheat producers are more negatively affected by the disease due to the economic losses from reduced water-use efficiency of infected plants. The economic insights from this article provide important implications for wheat management and research priority-setting.     

Durable press finish of cotton via dual curing using UV light and heat

Continuous photografting/crosslinking of polyethyleneglycol dimethacrylate oligomers onto cotton using a water-soluble benzophenone photoinitiator was investigated. Photografting increased with increasing irradiation dose, oligomer concentration and photoinitiator concentration. Maximum grafting efficiency of DM 400 and 600 were 83% and 79%, respectively. The photografting increased the wrinkle resistance of cotton implying surface crosslinking of cotton. Both surface crosslinking and bulk crosslinking of cotton were accomplished via dual curing of a mixed formulation containing both a thermally curable component (BTCA/SHP) and a UV-curable component. The wrinkle resistance of the crosslinked cotton was found to be higher when cured by thermal curing after UV curing rather than by UV curing after thermal curing due to the facile post-polymerization of the UV active component. The presence of crosslinks in the dually crosslinked cotton was verified with FT-IR and thermogravimetric analysis.     

Selected nutritional components and sensory attributes of cowpea (Vigna unguiculata [L.] Walp) leaves

Reports on the nutritional composition of cowpea leaves have been limited to a small number of lines and the palatability characteristics of leaves apparently have not been studied. This study was therefore undertaken on cowpea leaves to determine the nutrient composition of fifteen varieties and the sensory attributes of ten varieties grown in Ghana. Nutritional components studied were moisture, protein, phosphorus and ascorbic acid. The sensory attributes included leaf size, taste and overall acceptability. There were significant (p > 0.05) differences among varieties in all nutrient components (fresh and dry weight basis), leaf size and overall acceptability. The nutrient composition values, on a dry weight basis, ranged from 9.4 to 13.0% for moisture, 303.8 to 468.9 mg/100 g for phosphorus, 33.5 to 148.0 mg/100 g for ascorbic acid, and 27.1 to 34.7% for protein. Differences in the sensory scores of leaves for taste were not significant (p < 0.05). Overall acceptability positively correlated with leaf size. Moisture content was negatively correlated with overall acceptability, phosphorus and ascorbic acid. Results can be exploited in a breeding program to develop nutritionally superior and acceptable cowpea varieties which can be used for harvesting of both leaves and seeds.     

基于NDFT Goertzel滤波器的DTMF信号检测的改进方法

提出了一种基于NDFT Goertzel滤波器和逻辑判断的DTMF信号检测的改进方法.传统的基于Goertzel算法的检测方法需要计算8个频率点上的DFT,而改进方法根据按键不同只计算最多6个,最少2个频率点的NDFT.检测数字按键时,对于每个按键计算频率点数的期望值为4.1.改进的检测方法满足ITU的大部分规定.     

双重上市公司境内外风险信息披露一致性及其影响因素

通过对21家双重上市公司113个样本2000多条风险记录的两配对样本T检验发现,其境内外风险披露基本一致,对风险的描述基本一致,对风险的应对也基本一致。通过风险信息披露一致率、风险信息披露相同率与其影响因素的回归分析发现,规模、风险水平、资产负债率、账面市值比、境外上市地点、行业和年度会影响双重上市公司境内外风险信息披露的一致性。     

试论宋代农业信仰

在宋代,农业信仰与农业生产有着密切联系,贯穿在整个农业生产之中,在乡村社会里非常盛行。宋代农业信仰在调节民众心理、丰富民众文化生活、稳定社会秩序、加强社会凝聚力等方面发挥着重要的作用。     

发展劳务经济 促进小康建设--对提高安徽农村居民收入的思考

农民收入低是农村小康建设的难点.根据安徽省的资源禀赋和农村剩余劳动力存量巨大的现实,因势利导地发展劳务经济,既对提高农民收入具有现实作用,也必将对加快全面建设小康社会的进程起到积极的推动作用.     

油菜核不育两用系不育基因RAPD标记研究初报

为建立有效的不育基因分子标记辅助育种平台,以5个核不育两用系为研究材料,选用20条随机引物,利用RAPD混合集群分离分析法,对各两用系可育与不育基因池进行分子标记的初步分析.结果表明,在油研10号筛选到2个与不育基因相关的标记:BA2084-600和S1354-1300;在萝×诸中筛选到1个与不育基因相关的标记:LC02-500.在827AB、T18筛选到集团间有差异的引物,未筛选到通过集团单株检测的与其育性基因相关的标记.通过RAPD混合BSA法可以筛选到与不育基因相关的特异DNA标记.     

水稻两用核不育系育性转换光温反应型的分类研究

 在人工控制的9种光温处理下，对76份水稻两用核不育系的育性转换光温反应进行了研究。根据自交结实率的光周期效应、温度效应和光温互作效应的分析，供试的两用核不育系中，占96%的不育系的育性转换光温反应型可归为以下3种：（1）光周期敏感不育型，其统计学特征是育性转换的光温互作效应和光周期效应显著而温度效应不显著；（2）温度敏感不育型，其统计学特征是育性转换的温度效应显著而光周期效应不显著、光温互作效应显著或不显著；（3）光温互作不育型，其统计学特征是育性转换单独的光周期效应和温度效应不显著，仅光温互作效应显著。在供试的粳型不育系中，有34.8%、13.0%和47.8%的材料分属上述3种光温反应型;在供试的籼型不育系中,有73.6%和22.6%的材料分属温敏型和光温互作型,没有一份材料为光敏型。结果表明现有的两用核不育系育性转换光温反应是多型性的。文中还对实用性籼型两用核不育系育性转换光温反应型的选择问题作了讨论。     

对偶模型在畜禽饲料配方优化设计上的应用

 在一般线性规划配方模型基础上通过引入其对偶线性规划问题 ,以求解参与优化计算的养分项目即资源的影子价格。在配方优化设计领域 ,养分资源的影子价格揭示了当增减参与计算并希望最终达到的养分指标时对最终饲粮成本的影响程度。某一资源影子价格的值越大 ,表明其对配方的最低成本影响越突出 ;而影子价格为“零”的养分指标是指其在特定取值范围内 ,该指标的达成对最低成本不构成影响 ,同时笔者还讨论了今后我国饲料配方技术研究的深层次发展方向