基于花生生长中后期2020年8月1日和15日两个时相高分多光谱数据,构建40个作物分类遥感特征,采用ReliefF-Pearson方法优选出15个特征,构造作物可分的4种特征空间。采用最大似然分类法、支持向量机和随机森林分类器,分别耦合4种特征空间,...基于花生生长中后期2020年8月1日和15日两个时相高分多光谱数据,构建40个作物分类遥感特征,采用ReliefF-Pearson方法优选出15个特征,构造作物可分的4种特征空间。采用最大似然分类法、支持向量机和随机森林分类器,分别耦合4种特征空间,开展作物分类对比试验,进行分类精度和景观评价提出作物双时相遥感分类模型(dual-temporal remote sensing classification model for crop,C-DRSC)。结果表明:该模型具有较高的作物分类和花生识别能力,作物分类总体精度和Kappa系数分别为93.25%和0.89,平均形状指数和平均斑块分维指数分别为1.33和1.13;花生识别的用户精度和制图精度分别为96.20%和96.32%,平均形状指数和平均斑块分维指数分别为1.27和1.11。利用该模型在黄淮海地区的4个花生主产县开展夏花生种植面积遥感测算,与统计面积相比,面积测算相对误差为±16.25%,决定系数为0.9778(达到0.01显著性水平),模型具有较好的适用性。展开更多
Systematic characterization of available crop varieties using morphological traits is needed to fuel breeders＇ efforts in African eggplant. Twenty-eight accessions of African eggplant from three species of Solanum ae...Systematic characterization of available crop varieties using morphological traits is needed to fuel breeders＇ efforts in African eggplant. Twenty-eight accessions of African eggplant from three species of Solanum aethiopicum （16）, Solanum macrocarpon （9） and Solanum anguivi （3） were characterized using standard morphological descriptors. The experiment was laid out in Randomized Complete Block Design （RCBD） with three replications. The results indicated distinct and wide variations between the three Solanum species studied. There were however a lot of similarities between the S. aethiopicum and S. anguivi lines. This suggests the two materials being closer to each other than they are to the S. macrocarpon.展开更多
Currently, in fish farms, the controls of the physical characteristics of the fishes, for example, size and mass are made by means of the operation of fish removal, in which the tanks are emptied to capture the animal...Currently, in fish farms, the controls of the physical characteristics of the fishes, for example, size and mass are made by means of the operation of fish removal, in which the tanks are emptied to capture the animals and perform the biometry. This operation demands large volumes of water and generates effluent containing high concentrations of organic matter and nutrients that can contribute to the deterioration of water quality in the recipient bodies. Therefore, the development of technologies that use digital image processing, such as the moird technique and image analysis, can be important allies for the preservation of environmental quality by avoiding the fish removal and the discharge of effluents, increasing productivity due to optimization of the time and still the saving of water. To obtain the images a 9-liter glass aquarium, a support for notebook and light projector, a digital camera brand Samsung Galaxy Camera 2 were used. The objective of this work was to obtain the three-dimensional reconstruction of live fish in aquariums. In the future, the technique can be developed to obtain the mass and the volume of the fish in fish tanks, replacing the fish removal, allowing the preservation of water resources.展开更多
A differential fatherhood premium exists among selected groups of fathers of various socio-economic backgrounds. Besides marital status, residential arrangement, biological paternity, and other demographic dimensions,...A differential fatherhood premium exists among selected groups of fathers of various socio-economic backgrounds. Besides marital status, residential arrangement, biological paternity, and other demographic dimensions, the mechanisms associated with fathers＇ structural characteristics of work that produce divergent labor market outcomes are less well understood. The authors leveraged the cases of productivity and specialization, family and responsibility, and compensating differentials and examined the impacts of work context and occupational characteristics on the pay gap between fathers and non-fathers Based on joint data from the 1997-2015 National Longitudinal Survey of Youth （NLSY97） and Occupational Information Network （O＇NET） （n -- 37,138）, the authors used fixed-effects models to estimate the associations between job features and the fatherhood premium. The regression results showed that occupations entailing competition and requiring on-the-job training are associated with more wage bonus; occupations offering inflexible schedule are associated with less wage gain These work-related characteristics further emphasize fathers＇ work structure and context, human capital accumulation, and work-family conflict. Overall, these findings are consistent with the theoretical perspectives of productivity and specialization and compensating differentials, adding new evidences to the structural explanations of the fatherhood premium.展开更多
In this letter, a segment algorithm based on color feature of images is proposed. The al- gorithm separates the weed area from soil background according to the color eigenvalue, which is obtained by analyzing the colo...In this letter, a segment algorithm based on color feature of images is proposed. The al- gorithm separates the weed area from soil background according to the color eigenvalue, which is obtained by analyzing the color difference between the weeds and background in three color spaces RGB, rgb and HSI. The results of the experiment show that it can get notable effect in segmentation according to the color feature, and the possibility of successful segmentation is 87%-93%. This method can also be widely used in other fields which are complicated in the background of the image and facilely influenced in illumination, such as weed identification, tree species discrimination, fruit picking and so on.展开更多
The article considers the econophysical analysis of the relationship between monopoly and competition by using the methods, terms of physics. And it was investigated the philosophy of progress. It has been shown that ...The article considers the econophysical analysis of the relationship between monopoly and competition by using the methods, terms of physics. And it was investigated the philosophy of progress. It has been shown that in the transition from absolute monopoly to imperfect monopoly, the system becomes more complex, and its output characteristics depend on time, because monopoly is a natural, competitive is derivative process. Competition is created as a result of the interaction of at least two ~monopoly firms＂ through the ~market field＂ that they create to increase the production which is necessary of non-linear products over time. To do this, it is sufficient to have a multitude of firms interacting with each other under the influence force of ~market field＂. To create the necessary conditions, it is sufficient to have a high level of university education and a legal field for competition and unbreakable antitrust legislation. By acquiring technology and creating conditions for competition in the market, it is possible to achieve progress even without having a strong science. The term ~progress＂ has received a new content and is defined as the value of a numerically equal increase in the rate of production per unit time or production per squared time. It has been shown that the relationship between monopoly and competition is very simple and there is no contradiction between them. Initially, the market is born as a monopoly, and then analogical firms were created, competition between firms begins展开更多
The strained cyclopropane and/or cyclobutane subunits occurred in many complex natural products including terpenoids, steroids and alkaloids. Natural products with cyclopropane and/or cyclobutane motifs not only furni...The strained cyclopropane and/or cyclobutane subunits occurred in many complex natural products including terpenoids, steroids and alkaloids. Natural products with cyclopropane and/or cyclobutane motifs not only furnished fascinating structures, but also exhibited versatile biological activities, such as cytotoxic, anti-HIM antimicrobial, antiviral, and immunosuppressive effects. This review covered a large array of structurally unique natural products with strained cyclopropane and/or cyclobutane motifs and summarized their structural features, distributions, biological activities, as well as biogenetic considerations.展开更多
文摘基于花生生长中后期2020年8月1日和15日两个时相高分多光谱数据,构建40个作物分类遥感特征,采用ReliefF-Pearson方法优选出15个特征,构造作物可分的4种特征空间。采用最大似然分类法、支持向量机和随机森林分类器,分别耦合4种特征空间,开展作物分类对比试验,进行分类精度和景观评价提出作物双时相遥感分类模型(dual-temporal remote sensing classification model for crop,C-DRSC)。结果表明:该模型具有较高的作物分类和花生识别能力,作物分类总体精度和Kappa系数分别为93.25%和0.89,平均形状指数和平均斑块分维指数分别为1.33和1.13;花生识别的用户精度和制图精度分别为96.20%和96.32%,平均形状指数和平均斑块分维指数分别为1.27和1.11。利用该模型在黄淮海地区的4个花生主产县开展夏花生种植面积遥感测算,与统计面积相比,面积测算相对误差为±16.25%,决定系数为0.9778(达到0.01显著性水平),模型具有较好的适用性。
文摘Systematic characterization of available crop varieties using morphological traits is needed to fuel breeders＇ efforts in African eggplant. Twenty-eight accessions of African eggplant from three species of Solanum aethiopicum （16）, Solanum macrocarpon （9） and Solanum anguivi （3） were characterized using standard morphological descriptors. The experiment was laid out in Randomized Complete Block Design （RCBD） with three replications. The results indicated distinct and wide variations between the three Solanum species studied. There were however a lot of similarities between the S. aethiopicum and S. anguivi lines. This suggests the two materials being closer to each other than they are to the S. macrocarpon.
文摘Currently, in fish farms, the controls of the physical characteristics of the fishes, for example, size and mass are made by means of the operation of fish removal, in which the tanks are emptied to capture the animals and perform the biometry. This operation demands large volumes of water and generates effluent containing high concentrations of organic matter and nutrients that can contribute to the deterioration of water quality in the recipient bodies. Therefore, the development of technologies that use digital image processing, such as the moird technique and image analysis, can be important allies for the preservation of environmental quality by avoiding the fish removal and the discharge of effluents, increasing productivity due to optimization of the time and still the saving of water. To obtain the images a 9-liter glass aquarium, a support for notebook and light projector, a digital camera brand Samsung Galaxy Camera 2 were used. The objective of this work was to obtain the three-dimensional reconstruction of live fish in aquariums. In the future, the technique can be developed to obtain the mass and the volume of the fish in fish tanks, replacing the fish removal, allowing the preservation of water resources.
文摘A differential fatherhood premium exists among selected groups of fathers of various socio-economic backgrounds. Besides marital status, residential arrangement, biological paternity, and other demographic dimensions, the mechanisms associated with fathers＇ structural characteristics of work that produce divergent labor market outcomes are less well understood. The authors leveraged the cases of productivity and specialization, family and responsibility, and compensating differentials and examined the impacts of work context and occupational characteristics on the pay gap between fathers and non-fathers Based on joint data from the 1997-2015 National Longitudinal Survey of Youth （NLSY97） and Occupational Information Network （O＇NET） （n -- 37,138）, the authors used fixed-effects models to estimate the associations between job features and the fatherhood premium. The regression results showed that occupations entailing competition and requiring on-the-job training are associated with more wage bonus; occupations offering inflexible schedule are associated with less wage gain These work-related characteristics further emphasize fathers＇ work structure and context, human capital accumulation, and work-family conflict. Overall, these findings are consistent with the theoretical perspectives of productivity and specialization and compensating differentials, adding new evidences to the structural explanations of the fatherhood premium.
文摘In this letter, a segment algorithm based on color feature of images is proposed. The al- gorithm separates the weed area from soil background according to the color eigenvalue, which is obtained by analyzing the color difference between the weeds and background in three color spaces RGB, rgb and HSI. The results of the experiment show that it can get notable effect in segmentation according to the color feature, and the possibility of successful segmentation is 87%-93%. This method can also be widely used in other fields which are complicated in the background of the image and facilely influenced in illumination, such as weed identification, tree species discrimination, fruit picking and so on.
文摘The article considers the econophysical analysis of the relationship between monopoly and competition by using the methods, terms of physics. And it was investigated the philosophy of progress. It has been shown that in the transition from absolute monopoly to imperfect monopoly, the system becomes more complex, and its output characteristics depend on time, because monopoly is a natural, competitive is derivative process. Competition is created as a result of the interaction of at least two ~monopoly firms＂ through the ~market field＂ that they create to increase the production which is necessary of non-linear products over time. To do this, it is sufficient to have a multitude of firms interacting with each other under the influence force of ~market field＂. To create the necessary conditions, it is sufficient to have a high level of university education and a legal field for competition and unbreakable antitrust legislation. By acquiring technology and creating conditions for competition in the market, it is possible to achieve progress even without having a strong science. The term ~progress＂ has received a new content and is defined as the value of a numerically equal increase in the rate of production per unit time or production per squared time. It has been shown that the relationship between monopoly and competition is very simple and there is no contradiction between them. Initially, the market is born as a monopoly, and then analogical firms were created, competition between firms begins
基金supported by the National Natural Science Foundation of China (21532007)
文摘The strained cyclopropane and/or cyclobutane subunits occurred in many complex natural products including terpenoids, steroids and alkaloids. Natural products with cyclopropane and/or cyclobutane motifs not only furnished fascinating structures, but also exhibited versatile biological activities, such as cytotoxic, anti-HIM antimicrobial, antiviral, and immunosuppressive effects. This review covered a large array of structurally unique natural products with strained cyclopropane and/or cyclobutane motifs and summarized their structural features, distributions, biological activities, as well as biogenetic considerations.
