检索结果-南通市图书馆

Geographic variation in sexual selection and implications for speciation in the Barn Swallow

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Birds 2015年第1期5卷 30-42页

作者： Elizabeth SC Scordato Rebecca j Safran Department of Ecology and Evolutionary Biology The University of Colorado

Barn Swallows(Hirundo rustica), a group of passerine birds comprised of six closely related subspecies, are well known throughout their nearly worldwide distribution, in part because of their close association with human settlements.A tractable species for both individual-based and population-level studies, Barn Swallows are a prominent model system in evolutionary, ecological, and behavioral research. Here we review work on sexual selection and population divergence in this species complex, focusing on comparative studies among populations and *** summarize variation in the targets of mate choice and in the information conveyed by sexually selected traits, and conclude that the benefits advertised by different traits may vary geographically. Finally, we consider the role of sexual selection as a driver of population divergence in this widespread and phenotypically variable species complex.

关键词： Barn Swallow Geographic variation Natural selection Sexual selection Speciation Tail streamers Ventral color

A Project-Based Sustainability Rating Tool for Pavement maintenance

在线全文

学校读者我要写书评

暂无评论

Engineering 2018年第2期4卷 36-44页

作者： Yibo Zhang j.P. mohsen Department of Civil and Environmental Engineering University of Louisville Louisville KY 40208 USA

Pavements require maintenance to prevent undue distress or to restore performance; however, pavement maintenance and its impacts do not receive enough attention in many cases, and are either ignored or treated as a low priority, most current maintenance activities have budget issues and only focus on removing deteriorated pavement sections, Deferred pavement maintenance has impacts on the environment and on society, and may thus affect the costs associated with maintenance, A sustain- ability rating tool is a good way to list, explain, and evaluate such impacts, Various sustainahility rating tools have been developed for pavement; however, pavement maintenance has its own features that are different from those of the new construction, expansion, or reconstruction of pavements, This research project reviews nine sustainahility rating tools for pavement, although none of these tools fully describe maintenance features or can he directly applied to evaluate maintenance projects, A new sustainahility rating tool is then developed for pavement maintenance; this new tool can he used to evaluate individual projects and raise public awareness about the importance of pavement mainte- nance, Its details are described, and its use is demonstrated through an example to show the evaluation process and results,

关键词： Sustainability Pavement maintenance PSImRating tool Analytic hierarchy process

Distribution of Fucosylated Xyloglucans among the Walls of Different Cell Types in monocotyledons Determined by Immunofluorescence microscopy

在线全文

学校读者我要写书评

暂无评论

molecular Plant 2011年第1期4卷 144-156页

作者： maree Brennan Philip j. Harris School of Biological Sciences The University of Auckland Private Bag 92019 Auckland New Zealand

Xyloglucans in the non-lignified primary cell walls of different species of monocotyledons have diverse struc- tures, with widely varying proportions of oligosaccharide units that contain fucosylated side chains （F side chains）. To determine whether fucosylated xyloglucans occur in all non-lignified walls in a range of monocotyledon species, we used immunofluorescence microscopy with the monoclonal antibody CCRC-m1. The epitope of this antibody, α-L-FUCp-（1 →2）- β-D-Galp, occurs in F side chains. In most non-commelinid monocotyledons, the epitope was found in all non-lignified walls. A similar distribution was found in the palm Phoenix canariensis, which is a member of the basal commelinid order Arecales. However, in the other commelinid orders Zingiberales, Commelinales, and Poales, the occurrence of the epitope was restricted, sometimes occurring in only the phloem walls, but often also in walls of other cell types including stomatal guard and subsidiary cells and raphide idioblasts. No epitope was found in the walls of the commelinids Tradescantia virginiana （Commelinaceae, Commelinales） and Zea mays （Poaceae, Poales）, but it occurred in the phloem walls of two other Poaceae species, Lolium multiflorum and L. perenne. The distribution of the epitope is discussed in relation to xyloglucan structures in the different taxa. However, the functional significance of the restricted distributions is unknown.

关键词： Commelinid monocotyledons fucosylated xyloglucans immunofluorescence microscopy monoclona antibody CCRC-m1 non-commelinid monocotyledons plant cell wall.

Nuclear magnetic moments in covariant density functional theory

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Frontiers of physics 2018年第6期13卷 115-132页

作者： jian Li j.meng College of Physics Jilin UniversityChangchun 130012China Department of Physics Western Michigan UniversityKalamazooMI 49008USA State Key Laboratory of Nuclear Physics and Technology School of PhysicsPeking UniversityBeijing 100871China Yukawa Institute for Theoretical Physics Kyoto UniversityKyoto 606-8502Japan Department of Physics University of StellenboschStellenboschSouth Africa

Nuclear magnetic moment is an important physical variable and serves as a useful tool for the stringent test of nuclear models. For the past decades, the covariant density functional theory and its extension have been proved to be successful in describing the nuclear ground-states and excited states properties. However, a long-standing problem is its failure to predict magnetic moments. This article reviews the recent progress in the description of the nuclear magnetic moments within the covariant density functional theory. In particular, the magnetic moments of spherical odd-A nuclei with doubly closed shell core plus or minus one nucleon and deformed odd-A nuclei.

关键词： nuclear magnetic moment covariant density functional theory meson exchange current configuration mixing

Activity-dependent signaling mechanisms regulating adult hippocampal neural stem cells and their progeny

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Neuroscience Bulletin 2014年第4期30卷 542-556页

作者： Andrew j.Crowther juan Song Graduate Program of Neurobiology Curriculum University of North CarolinaChapel HillNC 27599USA Department of Pharmacology University of North CarolinaChapel HillNC 27599USA Neuroscience Center/Neurobiology Curriculum University of North CarolinaChapel HillNC 27599USA School of medicine University of North CarolinaChapel HillNC 27599USA

Adult neural stem cells （NSCs） reside in a restricted microenvironment, where their development is controlled by subtle and presently underexplored cues. This raises a significant question： what instructions must be provided by this supporting niche to regulate NSC development and functions？ Signaling from the niche is proposed to control many aspects of NSC behavior, including balancing the quiescence and proliferation of NSCs, determining the cell division mode （symmetric versus asymmetric）, and preventing premature depletion of stem cells to maintain neurogenesis throughout life. Interactions between neurogenic niches and NSCs also govern the homeostatic regulation of adult neurogenesis under diverse physiological, environmental, and pathological conditions. An important implication from revisiting many previously-identified regulatory factors is that most of them （e.g., the antidepressant fluoxetine and exercise） affect gross neurogenesis by acting downstream of NSCs at the level of intermediate progenitors and neuroblasts, while leaving the NSC pool unaffected. Therefore, it is critically important to address how various niche components, signaling pathways, and environmental stimuli differentially regulate distinct stages of adult neurogenesis.

关键词： neural stem cell neuronal development neuronal plasticity

Complementary analysis of microsatellite tumor profile and mismatch repair defects in colorectal carcinomas

在线全文

学校读者我要写书评

暂无评论

World journal of Gastroenterology 2006年第37期12卷 5932-5940页

作者： Alfredo Blanes Salvador j Diaz-Cano Department of Pathology University of Malaga School of Medicine Malaga 29010 Spain Department of Histopathology King’s College Hospital and King’s College London School of Medicine London SE5 9RS United Kingdom

microsatellite instability (mSI) is a prognostic factor and a marker of defi cient mismatch repair (mmR) in colorectal adenocarcinomas (CRC). However, a proper application of this marker requires understanding the following: (1) The mSI concept: The PCR approach must amplify the correct locus and accurately identify the microsatellite pattern in the patient’s normal tissue. mSI is demonstrat- ed when the length of DNA sequences in a tumor differs from that of nontumor tissue. Any anomalous expansion or reduction of tandem repeats results in extra-bands normally located in the expected size range (100 bp, above or below the expected product), differ from the germline pattern by some multiple of the repeating unit, and must show appropriate stutter. (2) mSI mechanisms: mmR gene inactivation (by either mutation or protein down-regulation as frequently present in deep CRC com- partments) leads to mutation accumulation in a cell with every cellular division, resulting in malignant transforma- tion. These mechanisms can express tumor progression and result in a decreased prevalence of aneuploid cells and loss of the physiologic cell kinetic correlations in the deep CRC compartments. mSI molecular mechanisms are not necessarily independent from chromosomal in- stability and may coexist in a given CRC. (3) Because of intratumoural heterogeneity, at least two samples from each CRC should be screened, preferably from the su- perfi cial (tumor cells above the muscularis propria) and deep (tumor cells infi ltrating the muscularis propria) CRC compartments to cover the topographic tumor hetero- geneity. (4) Pathologists play a critical role in identify- ing microsatellite-unstable CRC, such as occur in young patients with synchronous or metachronous tumors or with tumors showing classic histologic features. In these cases, mSI testing and/or mmR immunohistochemistry are advisable, along with gene sequencing and genetic counseling if appropriate. mSI is an excellent functional an

关键词： Colon carcinoma microsatellites mismatch Repair Hereditary non-polyposis colon cancer

连接天空与大地斯特拉斯堡大学科学花园天文馆

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

室内设计与装修 2024年第8期 80-83页

作者： [法国]frenak+jullien [加拿大]Cardin julien [法国]m+mathieu holdrinet maxime Delvaux(摄影) 沙漏(编译) 不详

描绘天空、想象宇宙、谈论天文学,斯特拉斯堡大学科学花园天文馆梦幻般的维度,激发了由frenak+jullien (法国)领衔的建筑团队的灵感,并与副建筑师Cardin j ulien (加拿大)和项目建筑师m+mathieu holdrin1t(法国)共同创造了建筑的独特形... 详细信息

描绘天空、想象宇宙、谈论天文学,斯特拉斯堡大学科学花园天文馆梦幻般的维度,激发了由frenak+jullien (法国)领衔的建筑团队的灵感,并与副建筑师Cardin j ulien (加拿大)和项目建筑师m+mathieu holdrin1t(法国)共同创造了建筑的独特形式。该天文馆位于气势恢宏的动物学和地质学研究所之间,由2个深色体量组成,在园内丰富的绿色植物中显得格外醒目:一个截顶圆锥体,用于容纳138个座位的放映室及其入口长廊;一个圆柱体量,用于容纳科学园大厅及相关服务设施。截顶圆锥体直冲云霄,寓意对宇宙知识的永恒探索,而开放的大厅则指向科学园管理的众多场所。

关键词：科学园圆锥体直冲云霄服务设施天文馆绿色植物动物学天文学

在线全文

学校读者我要写书评

暂无评论

世界镁工业现状

轻金属 1990年第6期 46-48+35页

作者： j.m.Ridgway 姜运福

对1987年世界金属镁产量继续下跌的预测没有实现,尽管美国犹他州的阿马克斯(Amax)镁厂遭受了较大的洪水,但其产量仍上升了2～4％。美国矿务局估计数字表明,将比1986年增产4500吨,达到127500吨,而该公司估

关键词：生产能力马克斯犹他州日本欧洲经济共同体金属公司镁工业产能诺斯克美国铝业公司加拿大北美洲美元本位币白云石镁肥金属镁产量镁市场生产者波尔斯

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

香港地区环境^（14）C水平研究

地球化学 1995年第C期24卷 115-118页

作者：梁宝鎏 m．j．Stokes 仇士华蔡莲珍香港城市理工学院物理和材料科学系中国社会科学院考古研究所

香港地处中国的东南端，是东南亚的发达城市，矿物燃料有大量消耗。最近广东深圳大亚湾核电站已经启动，探测和研究环境１４Ｃ水平有利于环境监测。我们采集了香港不同地区生长的一年生陆地草本植物、海洋植物和大气中的ＣＯ２进行１４... 详细信息

香港地处中国的东南端，是东南亚的发达城市，矿物燃料有大量消耗。最近广东深圳大亚湾核电站已经启动，探测和研究环境１４Ｃ水平有利于环境监测。我们采集了香港不同地区生长的一年生陆地草本植物、海洋植物和大气中的ＣＯ２进行１４Ｃ测定，并与近年来中国广西地区采集的桂皮油样品测定结果作比较。结果表明，香港地区的环境^（１４）Ｃ水平同广西地区几乎没有差别，但都明显高干预示的平均值。目前数据作为监察基础。

关键词：香港地区矿物燃料 ^14C测定环境监测人为干扰 ^14C浓度变化