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N. H. Arias A. B. Houssay S. Pieretti 《Cellular and molecular life sciences : CMLS》1980,36(9):1133-1134
Summary Large masses that looked like tumours were found in place of the ovaries in rats with isotransplants of pituitaries, 11 months after this procedure. They were interpreted as being due to massive bilateral cystic hyperplasia and hypertrophy of both ovaries.Acknowledgments. This work was supported by research grants from the Fundación Cherny and from The Consejo Nacional de Investigaciones Científícas y Técnicas. 相似文献
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用脸谱图对太子河本溪市区段河流沉积物中重金属污染进行评价的研究 总被引:9,自引:0,他引:9
本文将沉积学原理及国际上新发展的两种重金属污染评价方法与多变量的图表示法——脸谱图相结合,对太子河本溪市区段河道沉积物中重金属的污染状况及潜在生态危害进行了综合性的评价研究。从脸谱图上可以直观地看出各采样点重金属的污染情况和潜在生态危害程度。从研究结果可以看出,太子河本溪市区段河道沉积物中重金属的污染是很严重的。 相似文献
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贾巍巍 《山西师范大学学报:自然科学版》2004,18(3):6-11
本文讨论F4上n维线性空间的k维子空间W,这些子空间都有特定的自同构群(实际上是典型群GLn(F4)的一个子群),根据群中元素形式的不同可将子空间W分为两类,并对寻找n维空间中形如这两类的n/2维自对偶子空间提供了一种采用降低维数寻找的方法。 相似文献
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多梯度复杂图像的分割 总被引:1,自引:1,他引:0
图像分割是一种重要的图像分析技术,它不仅得到人们广泛的重视和研究,也在实际中得到大量的应用。本文针对一些经典分割算法对多梯度复杂图像分割边缘定位不准确,易受噪声干扰的特点,提出了一种利用图像边缘区域对多梯度复杂图像进行自适应阈值分割的算法。通过对各种算法的比较,本算法抗干扰能力较强,稳定性好,而且完全自动,不需预先设定任何参数。对多种图像的实验表明本文方法十分有效。 相似文献
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Because of their high dispersal abilities, birds are expected to manifest marked genetic structuring only at relatively large geographic scales. However, it is not well known how factors like nest site fidelity in a largely resident species could limit gene flow and increase genetic structuring in birds. In this study we use RAPD markers to estimate genetic structuring in a strongly sedentary species of the American tropics, the Russet crowned Motmot ( Momotus mexicanus ), within a tropical dry forest in central Mexico. Genetic structuring was assessed among 3 populations separated by a mean distance of only 25 km. We report that 12.9% of the total genetic variation is explained by differences among sites, which is quite high for a bird at this geographic scale. We propose that high nest site fidelity, brought on by a scarcity of suitable nest substrates, may be responsible for high genetic structuring in this species. 相似文献
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孤岛油田馆(1 2)砂层组属于河流相沉积,其纵向、横向相变迅速,砂体难以大面积追踪,本利用河流结构单元分析法、标准层与辅助标志层控制下的“旋回-厚度”对比法,很好地解决了馆(1 2)地层的划分对比问题,其中馆(1 2)砂层组内辅助标志层的发现为地层的划分对比提供了重要的保证.根据结构单元分析、砂体的岩性特征、粒度特征、河流砂体的空间展布形态以及河流曲率的计算,对馆(1 2)河流沉积的垂向旋回性及沉积模式进行了研究。对比Miall的16种河流分类方案,孤岛油田馆(1 2)砂层组属于细粒曲流河沉积. 相似文献
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Janneth Arias María Catalina Ramírez Diana María Duarte María Paula Flórez Juan Pablo Sanabria 《Systemic Practice and Action Research》2016,29(4):379-403
Currently, both public and private organizations, as well as the academic milieu are developing social projects in order to strengthen and improve the quality of life. This is the case of Engineers Without Borders Colombia (ISFCOL for its Spanish acronym), an organization formed by engineering teachers and students from Los Andes University and the Minuto de Dios University Corporation that develops engineering projects within communities in order to solve environmental and social problems. However, based in the group’s experience, a problem has been identified regarding the absence of a methodology that promotes the active and effective participation of all the parties involved, which can prevent the accomplishment of otherwise technically viable, socially responsible, and sustainable projects. Looking to address this issue, this paper presents a methodological proposal for promoting the active participation of all the parties involved in engineering projects that have a social impact. The proposal is structured following the stages of the oCDIO context (Observe, Conceive, Design, Implement and Operate), and is successfully applied during the development of an ISFCOL project in which the participation of all the parties involved becomes a key element for the effective accomplishment of the engineering proposal and for the generation of socially responsible impacts. Namely, the project “Fortalecimiento Negocios Verdes Comunitarios Provincia del Guavio” (Community Green Businesses Strengthening in the Guavio Province) whose main goal was to strengthen the innovation and the entrepreneurship in the Guavio region communities, consolidating thus an active participation network of 400 members made up by small entrepreneurs and students from rural communities close to the city of Bogota and from higher education institutions. 相似文献