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湿地恢复研究综述 被引量:184
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作者 崔保山 刘兴土 《地球科学进展》 CAS CSCD 1999年第4期358-364,共7页
湿地恢复研究是当今恢复生态学研究的主要内容之一。从湿地恢复的基本概念入手,阐述了恢复与湿地恢复的基本内涵,简述了国内外湿地恢复研究的进展。以生态学原理为基础,分析了湿地恢复的3个基本原则,即可行性原则、稀缺性和优先性... 湿地恢复研究是当今恢复生态学研究的主要内容之一。从湿地恢复的基本概念入手,阐述了恢复与湿地恢复的基本内涵,简述了国内外湿地恢复研究的进展。以生态学原理为基础,分析了湿地恢复的3个基本原则,即可行性原则、稀缺性和优先性原则、美学原则。也阐述了湿地恢复的主要目标。从沼泽、河流及河缘湿地、湖泊出发,简述了湿地恢复的基本策略。文中还从生态、社会、经济相整合的角度剖析了湿地恢复的合理性问题。文章最后对湿地恢复项目计划的制定与监测进行了探讨。 展开更多
关键词 湿地恢复 恢复生态学 可行性 稀缺性 合理性 监测
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若尔盖湿地保护区生物多样性评价 被引量:15
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作者 郝云庆 王新 +3 位作者 刘少英 谢大军 赵杰 李华 《中国水土保持科学》 CSCD 2008年第z1期35-40,共6页
四川省若尔盖湿地是世界上最大的一块高原泥炭沼泽湿地,也是我国生物多样性保护的热点地区之一。保护区内维管植物共计50科165属414种;鸟类13目28科137种;兽类5目15科38种;两栖类动物1目2科3种;爬行类2目3科3种;鱼类有1目2科15种。其中... 四川省若尔盖湿地是世界上最大的一块高原泥炭沼泽湿地,也是我国生物多样性保护的热点地区之一。保护区内维管植物共计50科165属414种;鸟类13目28科137种;兽类5目15科38种;两栖类动物1目2科3种;爬行类2目3科3种;鱼类有1目2科15种。其中,国家Ⅱ级重点保护植物3种,中国特有属植物5属;国家Ⅰ级保护鸟类7种,Ⅱ级保护鸟类20种,我国特有鸟类7种;国家Ⅰ级保护兽类1种,国家Ⅱ级保护兽类7种,我国特有兽类6种。笔者选取了生物多样性、稀有性、生态系统的稳定性与安全性、面积的适宜性以及自然属性5个方面17个赋值指标,对保护区的生物多样性质量进行整体评价,总评价得分为73.5,表明保护区具有丰富的生物多样性和极高的保护价值。 展开更多
关键词 若尔盖湿地 生物多样性评价 稀有性 特有性
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基于CWSI及干旱稀遇程度的农业干旱指数构建及应用 被引量:8
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作者 赵焕 徐宗学 赵捷 《农业工程学报》 EI CAS CSCD 北大核心 2017年第9期116-125,F0004,共11页
土壤湿度降低会使作物生长受到水分胁迫,严重时发生农业干旱,对粮食安全造成不利影响,准确识别和有效监测农业干旱具有重要的现实意义。前人研究中,通常仅根据当前水分亏缺程度识别干旱事件,而不考虑其稀遇特征。该文基于蒸散发构建了... 土壤湿度降低会使作物生长受到水分胁迫,严重时发生农业干旱,对粮食安全造成不利影响,准确识别和有效监测农业干旱具有重要的现实意义。前人研究中,通常仅根据当前水分亏缺程度识别干旱事件,而不考虑其稀遇特征。该文基于蒸散发构建了综合考虑当前水分亏缺程度和干旱事件稀遇程度的农业干旱指数IEDI(integrated evapotranspirationdeficitindex),并基于该指数分析了中国东北3省2000-2014年农业干旱演变规律,探讨了气象要素对农业干旱以及农业干旱发生时段对粮食产量的影响。结果表明:1)与仅考虑水分亏缺程度的指标相比,综合考虑干旱稀遇程度的IEDI能更加有效地识别干旱年际差异,历史干旱事件、旱灾成灾面积和粮食产量验证了该指数的合理性;2)东北三省旱灾成灾面积与IEDI的相关系数均大于0.75,其中,吉林省最大,为0.88;粮食产量与IEDI的相关系数均大于0.60,其中,辽宁省最大,为0.78;3)吉林西部、辽宁西部易发生严重农业干旱,对气象干旱敏感程度高;4)当干旱发生的起始月份固定时,随干旱持续时间增加,干旱指数与产量的相关性先增强后减弱;当干旱持续时间固定时,干旱指数与产量的相关性与干旱发生的起始月份显著相关。总之,结合了干旱事件稀遇程度的指数可以有效识别农业干旱,为农业干旱监测提供了合理依据。 展开更多
关键词 农业 干旱 遥感 指数 农作物 水分亏缺 稀遇程度
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天坑的等级评价方法 被引量:8
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作者 罗书文 杨桃 +4 位作者 黄保健 覃星铭 邓亚东 史文强 李成展 《桂林理工大学学报》 CAS 北大核心 2014年第3期446-451,共6页
为了减少天坑等级评价中的主观性,通过分析天坑规模参数特征,选取天坑容积作为评价指标。运用皮尔逊Ⅲ型曲线作为计算模型,结果表明皮尔逊Ⅲ型曲线对天坑规模参数拟合程度较好,具有一定的适用性。根据模型计算样本上、下限频率值,结合... 为了减少天坑等级评价中的主观性,通过分析天坑规模参数特征,选取天坑容积作为评价指标。运用皮尔逊Ⅲ型曲线作为计算模型,结果表明皮尔逊Ⅲ型曲线对天坑规模参数拟合程度较好,具有一定的适用性。根据模型计算样本上、下限频率值,结合等比数列排频划分法将其分为4级,并计算各级分界值对应下的容积值V作为评价天坑等级的标准,即:小型V≤5.43 Mm3;中型5.43 Mm3<V≤18.11 Mm3;大型18.11 Mm3<V≤45.26 Mm3;特大型V>45.26 Mm3。通过与现有方法比较,认为该方法既能反映天坑样本总体情况,又能减少人的主观性因素,具有一定的科学价值和现实意义。 展开更多
关键词 天坑 等级 评价方法 皮尔逊Ⅲ型曲线 稀有性
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一种基于视觉注意模型的图像分类方法 被引量:5
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作者 宋雁斓 张瑞 +2 位作者 支琤 杨小康 陈尔康 《中国图象图形学报》 CSCD 北大核心 2008年第10期1886-1889,共4页
视觉选择性注意机制是人类视觉系统的重要组成部分。近年来的研究表明,自下而上的视觉选择性注意模型在物体识别等方面得到了良好的应用。但是,视觉选择性注意模型在描述图像内容时存在着明显的不足,一个显著的特征在某些情况下可能不... 视觉选择性注意机制是人类视觉系统的重要组成部分。近年来的研究表明,自下而上的视觉选择性注意模型在物体识别等方面得到了良好的应用。但是,视觉选择性注意模型在描述图像内容时存在着明显的不足,一个显著的特征在某些情况下可能不会得到注意,人眼更可能会注意到一幅图像里比较稀少的特征。针对上述情况,提出了一种基于视觉选择性注意模型和全局稀少性相结合的视觉注意模型进行图像分类。实验结果表明,该方法在多类物体分类中达到97.74%的总准确率,取到了非常好的效果。 展开更多
关键词 视觉系统 视觉注意 稀少性 图像分类
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系统发育多样性测度及其在生物多样性保护中的应用 被引量:3
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作者 李义明 《生物多样性》 CAS CSCD 1998年第1期49-54,共6页
生物多样性保护面临两个基本问题:如何确定生物多样性测度以及如何保护生物多样性。传统的生物多样性测度是以物种概念为基础的,用生态学和地理学方法确定各种生物多样性指数。其测度依赖于样方面积的大小,并且所有的物种在分类上同... 生物多样性保护面临两个基本问题:如何确定生物多样性测度以及如何保护生物多样性。传统的生物多样性测度是以物种概念为基础的,用生态学和地理学方法确定各种生物多样性指数。其测度依赖于样方面积的大小,并且所有的物种在分类上同等对待。系统发育多样性测度基于系统发育和遗传学的理论和方法,能确定某一物种对类群多样性的贡献大小。该方法比较复杂,只有在类群的系统发育或遗传资料比较齐全时方能应用。本文认为,物种生存力途径和系统发育多样性测度相结合有助于确定物种和生态系统保护的优先秩序。 展开更多
关键词 生物多样性 测度 稀有种 系统发育多样性 生存力
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Woody plant taxonomic,functional,and phylogenetic diversity decrease along elevational gradients in Andean tropical montane forests:Environmental filtering and arrival of temperate taxa
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作者 Guillermo Bañares-de-Dios Manuel J.Macía +6 位作者 Gabriel Arellano Íñigo Granzow-de la Cerda Julia Vega-álvarez Itziar Arnelas Carlos I.Espinosa Norma Salinas Luis Cayuela 《Plant Diversity》 SCIE CAS CSCD 2024年第4期491-501,共11页
Mountains are paramount for exploring biodiversity patterns due to the mosaic of topographies and climates encompassed over short distances.Biodiversity research has traditionally focused on taxonomic diversity when i... Mountains are paramount for exploring biodiversity patterns due to the mosaic of topographies and climates encompassed over short distances.Biodiversity research has traditionally focused on taxonomic diversity when investigating changes along elevational gradients,but other facets should be considered.For first time,we simultaneously assessed elevational trends in taxonomic,functional,and phylogenetic diversity of woody plants in Andean tropical montane forests and explored their underlying ecological and evolutionary causes.This investigation covered four transects(traversing ca.2200 m a.s.l.) encompassing 114 plots of 0.1 ha across a broad latitudinal range(ca.10°).Using Hill numbers to quantify abundance-based diversity among 37,869 individuals we observed a consistent decrease in taxonomic,functional,and phylogenetic diversity as elevation increased,although the decrease was less pronounced for higher Hill orders.The exception was a slight increase in phylogenetic diversity when dominant species were over-weighted.The decrease in taxonomic and functional diversity might be attributed to an environmental filtering process towards highlands,where the increasingly harsher conditions exclude species and functional strategies.Besides,the differences in steepness decrease between Hill orders suggest that rare species disproportionately contribute to functional diversity.For phylogenetic diversity the shifting elevational trend between Hill orders indicates a greater than previously considered influence in central Andean highlands of tropical lowlands originated species with strong niche conservatism relative to distantly related temperate lineages.This could be explained by a decreasing presence and abundance of temperate,extratropical taxa towards the central Andes relative to northern or southern Andes,where they are more prevalent. 展开更多
关键词 Altitudinal gradients ANDES Environmentalfiltering Out of the Tropical Lowlands Functional rarity Tropical Niche Conservatism
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基于关联度分析的炼焦煤稀有性研究 被引量:5
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作者 吴玉程 金智新 +5 位作者 包研科 邓存宝 郝朝瑜 王雪峰 陈曦 李雨成 《太原理工大学学报》 CAS 北大核心 2020年第2期157-161,共5页
炼焦煤资源十分稀缺,但造成其稀缺的影响因素尚不明确。应用列联表分析方法,分析了炼焦煤煤种与成煤植物、成煤年代、沉积环境、变质动力、地温梯度之间的关联性。结果表明:炼焦煤只存在于我国聚煤期的部分成煤年代;成煤植物中可形成凝... 炼焦煤资源十分稀缺,但造成其稀缺的影响因素尚不明确。应用列联表分析方法,分析了炼焦煤煤种与成煤植物、成煤年代、沉积环境、变质动力、地温梯度之间的关联性。结果表明:炼焦煤只存在于我国聚煤期的部分成煤年代;成煤植物中可形成凝胶体的物质是成煤的必要条件;湖泊相沉积环境具有较高的成煤概率;在满足上述条件后,变质动力和古地温条件是影响植物演化为炼焦煤的关键因素。研究成果可为更好地预估炼焦煤储量、保护炼焦煤资源提供参考。 展开更多
关键词 炼焦煤 稀有性 列联表 成煤过程 关联性 成煤植物 沉积环境
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公私物品的逻辑 被引量:4
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作者 何晓星 《浙江大学学报(人文社会科学版)》 CSSCI 2008年第6期154-162,共9页
关于公私物品的逻辑体系应建立以资源稀缺性为基础的新框架。资源稀缺性要求明确界定在消费博弈中人与人之间权利的关系,公私品就是这种权利关系的契约。以"排除他人不支付市场价格行使消费权利"定义排他性,将有无排他性作为... 关于公私物品的逻辑体系应建立以资源稀缺性为基础的新框架。资源稀缺性要求明确界定在消费博弈中人与人之间权利的关系,公私品就是这种权利关系的契约。以"排除他人不支付市场价格行使消费权利"定义排他性,将有无排他性作为区别公私品的单一标准,公私品就分别是具有非排他性、排他性契约的物品。公私品的性质是主客观、供求等的逻辑统一。是连续动态变化的量,一般物品都是不同程度公私混合的物品。也可从组织内外和供求关系两个新视角对公私品进行分类。公私品相互转化的实质是排他性价格的变化,取决于必要和充分条件即生产力和生产关系条件的共同作用,这主要是供求关系变化和产权界定成本收益之间的函数,并在此基础上产生了三种转化路径。 展开更多
关键词 公共品 稀缺性 定义 分类 转化
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Endoscopic mucosal resection of duodenal bulb adenocarcinoma with neuroendocrine features:An extremely rare case report 被引量:1
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作者 Ming-Yao Wen Yu Wang +1 位作者 Xiao-Yan Meng Hua-Ping Xie 《World Journal of Gastroenterology》 SCIE CAS 2015年第24期7608-7612,共5页
Duodenal adenocarcinoma, especially duodenal bulb with neuroendocrine features(NEF), is extremely rare. Here, we report one such case of duodenal bulb adenocarcinoma with neuroendocrine features. A 63-year-old Han Chi... Duodenal adenocarcinoma, especially duodenal bulb with neuroendocrine features(NEF), is extremely rare. Here, we report one such case of duodenal bulb adenocarcinoma with neuroendocrine features. A 63-year-old Han Chinese woman was admitted to our department with the diagnosis of a duodenal bulb polyp and underwent an endoscopic mucosal resection. The pathological findings confirmed it as duodenal bulb adenocarcinoma with NEF. The patient remains curative after one and half a years of follow-up. Duodenal adenocarcinoma with NEF might be a low malignant neuroendocrine tumor rather than a conventional adenocarcinoma. Endoscopic treatment, including endoscopic mucosal resection, might be an ideal option for the adenocarcinomas with NEF. 展开更多
关键词 DUODENAL ADENOCARCINOMA Neuroendocrinefeatures Endoscopic MUCOSAL RESECTION Duodenalbulb rarity
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The Effect of Willow Short Rotation Coppice Cultivation on the Biodiversity Quality of Ground-Layer Invertebrates
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作者 Michael Alan Williams Alan Feest 《Agricultural Sciences》 2022年第3期378-392,共15页
The biodiversity quality of ground-layer invertebrates within the cropped area of a plantation of the biomass crop willow short-rotation coppice (SRC) grown within a floodplain was compared to the biodiversity quality... The biodiversity quality of ground-layer invertebrates within the cropped area of a plantation of the biomass crop willow short-rotation coppice (SRC) grown within a floodplain was compared to the biodiversity quality of the neighbouring plots of floodplain grassland and a mixed deciduous woodland plantation. Pitfall traps were used to collect ground beetles (Carabidae) and arachnids (Araneae and Opiliones) in the plots over a period of two years. A range of biodiversity indices was used to assess the biodiversity quality of each of the three plots, and the willow SRC was compared to each of the controls using Mann-Whitney tests. The willow SRC transitioned from almost bare ground to young woodland during the two years of the study, which affected comparisons with alternative land uses as the habitat during the second year was very different from the habitat at the start of the study. Compared to plantation woodland, in the first year, the effect was mostly positive, but this declined in the second year. Compared to grassland there was a largely negative effect in both years. However, when in combination with other habitats, willow SRC cultivation on floodplain land may have an overall positive effect on invertebrate biodiversity quality. 展开更多
关键词 Biodiversity Quality BIOMASS Energy Crops rarity Short Rotation Coppice
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The Effect of <i>Miscanthus</i>Cultivation on the Biodiversity of Ground Beetles (Coleoptera: Carabidae), Spiders and Harvestmen (Arachnida: Araneae and Opiliones) 被引量:1
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作者 Michael A. Williams Alan Feest 《Agricultural Sciences》 2019年第7期903-917,共15页
In-crop invertebrate biodiversity of the perennial rhizomatous biomass crop Miscanthus was compared to the in-crop invertebrate biodiversity of adjacent agricultural land-uses. Ground beetles and arachnids (spiders an... In-crop invertebrate biodiversity of the perennial rhizomatous biomass crop Miscanthus was compared to the in-crop invertebrate biodiversity of adjacent agricultural land-uses. Ground beetles and arachnids (spiders and harvestmen) were used as indicators of invertebrate biodiversity and caught using pitfall traps over two years. Biodiversity measurements used were species richness, biomass, abundance, Simpson’s Index, and rarity values. The Miscanthus plantation had a significantly lower ground beetle and arachnid species richness, biomass and abundance than an adjacent mixed-use arable field and a significantly lower ground beetle biomass and abundance than an adjacent grassland. Reduced weed vegetation and lack of insects that feed on Miscanthus are likely to be significant factors. The findings contradict the conclusions of a previous study of Miscanthus impact on butterflies. This is the first major study to assess the in-crop biodiversity of an established plantation and shows that Miscanthus invertebrate biodiversity is poor in established plantations, when compared to adjacent conventional agricultural land-uses. 展开更多
关键词 Biomass Energy Crops BIODIVERSITY Quality Species Richness Simpson’s Index rarity
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稀有微生物群落研究进展 被引量:3
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作者 关健飞 沈智超 曹阳 《湖北农业科学》 2020年第15期5-11,共7页
微生物对人类生活和全球生物地球化学循环存在深刻影响,其中稀有微生物群落是评价微生物多样性的重要因素,是微生物遗传和功能多样性的存储库,具有驱动地球化学循环、指示环境变化、降解污染物、稳定群落结构等重要功能。介绍了稀有微... 微生物对人类生活和全球生物地球化学循环存在深刻影响,其中稀有微生物群落是评价微生物多样性的重要因素,是微生物遗传和功能多样性的存储库,具有驱动地球化学循环、指示环境变化、降解污染物、稳定群落结构等重要功能。介绍了稀有微生物群落的相关概念、类型、研究方法、存在机制及功能作用,为进一步研究微生物的生物地理学、探索微生物基因组等提供参考。 展开更多
关键词 稀有微生物 群落 稀有性 类型 功能
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基于缓存偏移量的P2P流媒体调度策略 被引量:2
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作者 王文波 范训礼 房鼎益 《计算机工程》 CAS CSCD 北大核心 2009年第23期50-52,共3页
现有P2P流媒体调度策略在确定数据块调度优先级时,未能综合考虑数据块稀缺度和紧迫度因素,导致了较差的播放连续度和启动延迟性能。提出的基于缓存偏移量的数据调度策略通过统计数据块在供求节点上的播放偏移量并对其加以处理,可有效解... 现有P2P流媒体调度策略在确定数据块调度优先级时,未能综合考虑数据块稀缺度和紧迫度因素,导致了较差的播放连续度和启动延迟性能。提出的基于缓存偏移量的数据调度策略通过统计数据块在供求节点上的播放偏移量并对其加以处理,可有效解决该问题,使播放连续度、启动延迟性能得到明显提高。 展开更多
关键词 P2P流媒体 数据调度 稀缺度 紧迫度 缓存偏移量
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中学生课外学业负担的成因及对学生心理健康的影响 被引量:3
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作者 张舒 《渤海大学学报(哲学社会科学版)》 2018年第5期128-133,共6页
校外培训机构的快速发展,加重了中学生的课外学业负担,也加重了学生家庭的经济负担,更重要的是,它也对学生的心理健康造成了负面影响。本文以数理方法分析了学生课外学业负担的成因,并依据心理资本和稀缺理论深入地剖析了课外学业负担... 校外培训机构的快速发展,加重了中学生的课外学业负担,也加重了学生家庭的经济负担,更重要的是,它也对学生的心理健康造成了负面影响。本文以数理方法分析了学生课外学业负担的成因,并依据心理资本和稀缺理论深入地剖析了课外学业负担会禁锢学生思想、影响学生心智和造成家庭焦虑三方面的后果,进而提出应以心理调适的方法来减轻学生的学业负担。 展开更多
关键词 学业负担 心理健康 心理资本 稀缺
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Diversity Dimensions of Freshwater Fish Species around the World
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作者 Carlos Granado-Lorencio Cástor Guisande +7 位作者 Patricia Pelayo-Villamil Ana Manjarrés-Hernández Emilio García-Roselló Juergen Heine Elisa Pérez-Costas Luis González-Vilas Jacinto González-Dacosta Jorge M. Lobo 《Journal of Geographic Information System》 2021年第1期1-18,共18页
The quality and coverage of the available taxonomical and geographical information and the recognition that diversity is multi-faceted are two main factors that hinder to understand the spatial and temporal variations... The quality and coverage of the available taxonomical and geographical information and the recognition that diversity is multi-faceted are two main factors that hinder to understand the spatial and temporal variations of biodiversity. In this study, we aim to quantify the global distribution of five diversity components used to assess freshwater fish diversity in river basins around the world. The multidimensional character of these diversity components was estimated and the so obtained diversity dimensions mapped. This was done taking into account those well-surveyed basins discriminated by considering collector’s curves, and additionally by controlling for the effect of survey effort on all considered diversity components. A total of 1,472,109 occurrence records were analysed, corresponding to 17,292 species of freshwater fishes. Five diversity components were considered: functional richness, species richness, taxonomic diversity, and two rarity measures. Well-surveyed river basins were discriminated using accumulation curves. The effects of survey biases and knowledge gaps were minimized by determining the relationship of each component with the completeness values calculated for each river basin. The geographical pattern derived from raw data is skewed by the unequal knowledge available, and all diversity components were positively correlated with completeness values. The first dimension described the association between species richness and functional diversity. The second dimension represented rarity and taxonomic diversity. The congruence between species richness and functional diversity suggests that ecosystem functions increase with the number of fish species present in river basins and that a decrease in species richness may involve a loss of functionality. The levels of rarity and taxonomic diversity of many species-poor basins found in arid and cold regions suggest that the distinctiveness of their freshwater fishes is primarily a consequence of how isolated these basins are. 展开更多
关键词 Diversity Components Functional Diversity Species Richness rarity Taxonomic Diversity
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Floristic Composition and Diversity of Freshwater Swamp Forests in the Niger Basin of Nigeria
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作者 Nwabueze I. Igu Robert Marchant 《Open Journal of Forestry》 2018年第4期567-584,共18页
Freshwater swamp forests are wetland ecosystems with poorly understood ecology. With increasing degradation across the Niger basin (where it is the most extensive across West Africa), it is deemed important to underst... Freshwater swamp forests are wetland ecosystems with poorly understood ecology. With increasing degradation across the Niger basin (where it is the most extensive across West Africa), it is deemed important to understand its distribution, patterns and composition. This is aimed at both increasing botanical inventories in the ecosystem and also elucidate vital steps that could guide its effective conservation. This study assessed the floristic composition and diversity across 16 one hectare forest plots and sought to show how varied the sites were in terms of diversity, stem density and basal area. The survey showed that the area had 116 species within 82 genera and 36 families. The number of species found in each of the disturbed sites was generally higher than the intact forest sites, which was not diverse but comprised many trees with higher basal area. While the stem density which ranged from 94 - 409 stems·ha-1 is comparable with that of other tropical forests, species richness was low (ranging from 8.65 - 0.52). Diversity ranged from 3.38 - 0.98 and was higher in disturbed sites than in intact locations. Species richness was generally low and implies that loss of species in the ecosystem could threaten species’ existence and conservation in the ecosystem. Disturbed locations had more species than the intact zones and as such show the importance of targeted conservation not only in the undisturbed locations but also in the disturbed locations with a higher species value and potential for species stability of the ecosystem. 展开更多
关键词 BIODIVERSITY Forest Disturbance Species rarity Stem Density TROPICAL FORESTS
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Looking for a Rarity: Histiocytic Sarcoma
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作者 Joana de Castro Rocha Isabel Paiva Ana Rita Cruz 《Journal of Cancer Therapy》 2016年第2期79-82,共4页
Histiocytic sarcoma is an extremely rare and very aggressive malignancy, with poor prognosis. The cases described in the literature are few and the treatment is not currently considered consensual. The clinical presen... Histiocytic sarcoma is an extremely rare and very aggressive malignancy, with poor prognosis. The cases described in the literature are few and the treatment is not currently considered consensual. The clinical presentation is very variable. Its characterization is made based primarily on the histology. The authors present a case of an 82-year-old woman, with multiple adenopatic retroperitoneal and left iliac conglomerates, with left leg associated edema (extrinsic compression by conglomerates). After intensive study and approach ganglion biopsy, the histologic diagnosis revealed a histiocytic sarcoma. 展开更多
关键词 Histiocytic Sarcoma rarity Aggressive Malignancy LYMPHADENOPATHY
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翘嘴鳜线粒体基因组全序列的克隆与特征分析 被引量:2
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作者 陈敦学 李玉珑 +5 位作者 宾石玉 农小献 刘希良 成嘉 张建社 褚武英 《广西师范大学学报(自然科学版)》 CAS 北大核心 2011年第4期111-116,共6页
通过直接测序的方法获得翘嘴鳜线粒体DNA基因组全序列(GenBank:JF972568)。翘嘴鳜线粒体基因组全长为16 496 bp,其包含13个编码蛋白基因、22个tRNA基因、2个rRNA基因和1个Control region区域。整个翘嘴鳜线粒体DNA利用率非常高,仅仅只有... 通过直接测序的方法获得翘嘴鳜线粒体DNA基因组全序列(GenBank:JF972568)。翘嘴鳜线粒体基因组全长为16 496 bp,其包含13个编码蛋白基因、22个tRNA基因、2个rRNA基因和1个Control region区域。整个翘嘴鳜线粒体DNA利用率非常高,仅仅只有32 bp的基因间隔和35 bp的基因重叠。翘嘴鳜线粒体的编码蛋白基因具有明显的A+T偏好性,同时整个基因组中G碱基含量非常低,仅有16.2%。翘嘴鳜线粒体基因起始密码子以ATG为主,但终止密码子却呈现多样性。翘嘴鳜22个tRNA基因只有tRNA-leu(UUR、CUN)和tRNA-Ser(UCN、AGY)有2个密码子,22个tRNA按位置可分为3个基因簇(IQM、WANCY、HSL)。翘嘴鳜rRNA的位置和大小与其他鱼类相似,D-Loop区域具有明显的A+T碱基偏好性。翘嘴鳜线粒体全序列的克隆对进一步确定鳜类分类地位和多样性保护具有重要意义。 展开更多
关键词 翘嘴鳜 线粒体基因组 密码子偏好性 多样性 tRNA基因簇
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劳动价值论的稀少性问题研究
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作者 李松龄 《长沙电力学院学报(社会科学版)》 2001年第3期34-37,共4页
将稀少性引入劳动价值是对自然资源、社会资源的稀少性的认识发展的必然 ,是市场经济发展的必然要求。通过将稀少性引入劳动价值论 ,我们能够对社会主义市场经济体制变革中出现的许多问题作出了比较圆满的解释。
关键词 社会主义市场经济 劳动 价值 稀少性 丰裕性 劳动价值论 制度变迁
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