1700-1860年间中国东北谷物与大豆的贸易

本文主要阐述十七至十八世纪之际,中国东北地区的谷物和大豆的生产与贸易的数量变化。经过十七世纪的恢复性发展,18世纪中叶,东北地区垦殖面积扩大,大豆产量增长较快并部分用于输出。作者从清政府海关关税档案、历史文献记载的耕地数字以及当地用于口粮的谷物生产等方面进行综合研究,考证了东北地区的大豆生产量及贸易量,得出了与以往学术界不同的研究结论。     

中国蜂蜜贸易国际竞争力分析

中国蜂蜜出口量占世界市场的20%以上,是我国出口的主要畜产品之一。通过与其他主要蜂蜜出口国的国际竞争力比较分析发现,中国蜂蜜竞争力有下滑的趋势,主要影响因素是出口价格低,生产规模小和质量不稳定等,提出了提高蜂蜜国际竞争力要健全行业协会功能,扶持龙头企业,提高产品含金量和完善安全监控体系等应对措施。     

用模糊关系方程预估林分蓄积量的研究

以林分的年龄、胸高断面积、优势木平均高为预估因子,用模糊关系方程预估林分蓄积量。经检验:系统误差为0.274％,精度为96.79％。表明该法预估效果良好,简单易行,有较大的实用价值。     

陕西关中小麦全麦粉SDS沉淀值与膨胀体积的遗传研究

为了给小麦品质育种早代选择指标的确定提供理论依据．选用5个品质性状不同的陕西关中小麦品种及其双列杂交的F1为材料，分析了全麦粉SDS沉淀值和膨胀体积的遗传特性。全麦粉SDS沉淀值和膨胀体积的平均值分别为67．66ml和6．09ml／g．其中沉淀值变异幅度较大，变异系数较高．而膨胀体积变异幅度较小，变异系数较低。SDS沉淀值的广义遗传力和狭义遗传力分别为98、42％和97．06％；膨胀体积的广义遗传力和狭义遗传力分别为54．75％和10．82％。对陕西关中小麦品质育种配制的组合而言，全麦粉SDS沉淀值可作为小麦育种分离早代蛋白质品质选择的指标，而全麦粉膨胀体积最好在育种高代进行选择。     

Worldview-2不同波段纹理特征对森林蓄积量估算精度影响

为检测高分辨率遥感影像不同波段纹理特征对于森林蓄积量估算精度的影响,以湖北省荆门市京山县太子山林场马尾松纯林为对象,基于灰度共生矩阵的方法分别提取高分辨率遥感影像Worldview-2 红光、绿光、蓝光、近红外波段和全色波段的纹理特征,利用随机森林算法,分别建立野外样地蓄积量与纹理参数的模型。结果表明,全色波段对马尾松森林的精度最高（R²=0.86,RMSE=47.37 m³·hm^-2）,其次是绿色波段（R²=0.85,RMSE=50.82 m³·hm^-2）和近红外波段（R²=0.85,RMSE=46.85 m³·hm^-2）,蓝色波段（R²=0.68,RMSE=60.72 m³·hm^-2）和红色波段（R²=0.69,RMSE=56.27 m³·hm^-2）的精度最低;窗口大小对模型精度影响较小,全色波段的R²取值在0.82~0.86,RMSE取值在47.66~51.99 m³·hm^-2,多光谱波段的R²取值在0.88~0.89;蓝色和红色波段的非相似度（DIS）的估算模型精度相对较高,绿色波段的对比度（CON）（R²=0.87,RMSE=46.21 m³·hm^-2）估算精度最高,红色波段的非相似度（R²=0.68,RMSE=58.30 m³·hm^-2）估算精度较高,近红外波段的角二阶矩阵（ASM）（R²=0.68,RMSE=60.30 m³·hm^-2）精度最高,全色波段的对比度、相关性、熵、变化量模型精度较高,R2为0.85。利用高分辨率遥感影像纹理特征估算森林参数时需综合考虑不同波段的纹理特征对模型的贡献。     

A two-dimensional numerical model of wind-induced flow and water quality in closed water bodies

In closed water bodies, such as reservoirs and lakes, where the exchange with external waters is usually small, the wind-induced flow significantly affects their water quality by mixing the surface waters and transfering heat down through the water column. However, the circulation caused by wind acting on the water surface can be influenced by the excessive growth of aquatic plants in summer, which may make their water quality to become worse. Therefore, understanding the response of the closed water bodies to winds acting on the water surface is of great significance in examining and maintaining their water quality in good condition. With that significance, this research has been done to build a two-dimensional, unsteady, laterally averaged model for simulating the circulation and water quality in closed water bodies. To verify the model, the Tabiishidani reservoir located in Sasaguri town, Fukuoka prefecture, Japan, was chosen as a case study. To illustrate the methodology of the research, water temperature of the reservoir was chosen to calibrate the model. After calibration, the model was applied to simulate water temperature in the Tabiishidani reservoir under different patterns of meteorology. The results of simulation clarified the change in water temperature distribution along the depth of the reservoir under the different patterns of meteorology. This research shows that the model can be a suitable tool for simulating the circulation and water temperature in closed water bodies. Moreover, the model can be extended to simulate the circulation and any variable of water quality in closed water bodies with the coverage of aquatic plants on the water surface.     

A comparison of tuber shape and tissue composition of potato genotypes

Summary Seven tuber attributes were measured for a number of cultivars and breeding lines: two shape indices for the length and flatness of the potato, one index for the narrowness of the pith, three volume parameters for the relative proportion of cortical, perimedullaryand pith zones of the potato, and specific gravity. The three index traits, specific gravity and volume of the pith zone showed highly significant genotype x year interactions. Significant genotypic and seasonal effects were usually detected for the three volume traits and specific gravity. The percentage volume of the cortical and perimedullary zones showed no genotype x year interactions. Correlations between the traits were estimated, and a factor analysis was performed based on the correlation matrix. One factor appeared to control the negative allometric relationship between the percentage volumes of the cortical and perimedullary zones, and another factor indicated the relationship between the length and flatness indices of the potato. The negative association of the percentage volume with the narrowness index of the pith and positive association between the length of tuber and narrowness of the pith suggested that long potatoes having narrow pith were inclined to have a smaller volume of pith. Factor analysis can be used to identify genotypes with desirable tuber attributes.     

Correlation of Nitrogen Concentration with Dry-Matter Partitioning to Spikelets and Total Husk Volume on the Panicle in Japonica Rice

Summary

A rice husk restricts the grain development physically. We examined the correlation of the total husk volume on a panicle, a parameter of yield capacity, with the nitrogen concentration (per dry weight) and the dry weight of the above-ground part of the plant, using single-stem-trained japonica rice (cv. Nipponbare) plants. The growth of rice plants was regulated by shading at two levels and nitrogen application at three levels from about 40 days before the heading (about 10 days before the panicle initiation). The number of spikelets per dry weight of the above-ground part of the plant at the end of the spikelet differentiation stage was linearly correlated with the nitrogen concentration at that time. The ratio of the spikelet dry weight at heading to the dry weight of the above-ground part of the plant at the end of the spikelet differentiation stage increased as the nitrogen concentration increased at a low nitrogen concentration, but the increase of the ratio slowed down at a nitrogen concentration of 2%. Decrease in dry weight of the spikelet resulted in a decrease of lemma size. Therefore, the ratio of the total husk volume on a panicle to the plant dry weight at the end of spikelet differentiation stage also increased as the nitrogen concentration increased at a low nitrogen concentration, but the increase stopped at a nitrogen concentration of 2% in contrast to the ratio of the spikelet number to the dry weight of the plant. These results suggest that, to increase the total husk volume on a panicle by nitrogen application, dry-matter production must be increased by the nitrogen application.     

Effects of high potassium chloride supplementation on water intake and bodyweight gains in pregnant and lactating mice

Thirty‐one ICR pregnant mice were assigned to a control or a potassium chloride (KCl) diet group to clarify the effects of KCl supplementation on water intake, bodyweight gains and serum components in pregnant and lactating mice, and 5% KCl was supplemented in KCl diets from 6.5 days post coitus to 1 or 14 days after parturition. Feed intake was not affected by treatment, but supplemental KCl decreased bodyweight gains of lactating mice and their neonatal mice. Water intake and urine volume of KCl supplemented mice were significantly higher than those of control mice during pregnancy and supplemental KCl decreased serum urea N in pregnant mice. Supplemental KCl increased water intake drastically in lactating mice immediately after parturition and increased serum K at 14 days after parturition. Histological alteration using hematoxylin–eosin was not found in the kidney of each mouse at 1 or 14 days after parturition. These results indicate that high KCl supplementation accelerates water intake in lactating mice and prevents bodyweight gains of maternal and neonatal mice during lactation.     

利用TM影像和偏最小二乘回归方法估测三峡库区森林蓄积量

为进一步提高遥感模型预测森林蓄积量的精度和稳定性,分析了遥感特征因子、地形特征因子、郁闭度与森林蓄积量之间的相关关系。在此基础上,利用偏最小二乘回归方法构建了森林蓄积量遥感预测模型,生成了三峡库区森林蓄积量空间等级分布图,并与地面实测值进行比较。结果表明:该模型的最佳主成分数为3,且郁闭度、海拔、坡度、TM1、TM2、TM3、TM4、TM5、TM7、NDVI、RVI、TM7/TM3、TM4×TM3/TM2、亮度和湿度为预测森林蓄积量的入选变量;森林蓄积量预测的调整决定系数为0.524,相对误差为7.33%,均方根误差为1.763m3;利用该模型计算出三峡库区森林总蓄积量约为1.12亿m3,总体预测精度达到89.58%。研究结果为提高森林蓄积量遥感预测的精度提供了一种有效手段,有利于大面积应用和推广。