检索结果-南通市图书馆

世界热带农业信息 1987年第1期 51-52页

作者： k.leuschner 徐伟亮

木薯绿螨已在非洲东部、西部和中部蔓延,对木薯植株造成了不同程度的危害,故引起非洲木薯生产国的关注,并开展了绿螨的生物学和生态学及木薯抗性品种的研究。本文概述了绿螨的生活习性、繁殖和传播途径。另外还找到一种可筛选抗性木薯... 详细信息

木薯绿螨已在非洲东部、西部和中部蔓延,对木薯植株造成了不同程度的危害,故引起非洲木薯生产国的关注,并开展了绿螨的生物学和生态学及木薯抗性品种的研究。本文概述了绿螨的生活习性、繁殖和传播途径。另外还找到一种可筛选抗性木薯种质的方法。

关键词：木薯种质非洲薯类作物国际热带农业研究所植株

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

甘薯对病毒病复合体的抗性

园艺与种苗 1984年第3期30卷 37-39页

作者： S.k.Hahn E.R.Terry k.leuschner 刘铭菊

甘薯病毒病复合体(SPVD)在世界上广泛蔓延,尤以非洲为甚。Schaeters 等曾报道,在尼日利亚甘薯病毒病复合体由两种成份构成,其一是通过蚜虫以非持久方式进行传播、并在巴西牵牛(Ipomoea setosa ker.)上引起明脉症状的病毒,而且在没有第... 详细信息

甘薯病毒病复合体(SPVD)在世界上广泛蔓延,尤以非洲为甚。Schaeters 等曾报道,在尼日利亚甘薯病毒病复合体由两种成份构成,其一是通过蚜虫以非持久方式进行传播、并在巴西牵牛(Ipomoea setosa ker.)上引起明脉症状的病毒,而且在没有第二种成分的情况下呈潜隐状态。另一种是目前尚未识别的由棉粉虱(Bemisia tabaci Genn.)

关键词：甘薯病毒复合体病毒病病毒传染病传染病双列杂交

Stand dynamics of the drought-affected floodplain forests of Araguaia River,Brazilian Amazon

在线全文

学校读者我要写书评

暂无评论

Forest Ecosystems 2017年第3期4卷 201-210页

作者： Jürgen Homeier Dariusz kurzatkowski Christoph leuschner Plant Ecology Albrecht von Haller Institute for Plant Sciences University of Goettingen

Background： The floodplain forests of Araguaia River, a clear-water river in the southeastern Amazon（Tocantins State, Brazil）, are characterized by seasonal flooding up to 3.5 m height, low nutrient levels in the water, and seasonal drought periods of 4–5 ***： We studied the forest dynamics（tree diameter growth, tree mortality and recruitment） of this unique forest ecosystem over a 5-year period by repeated censuses in 12 permanent plots established along a flooding ***： The cumulative basal area in the plots increased by 0.84（±0.45） m^2·ha^-1·yr^-1（mean ±SD） in the annual y-flooded（AF） plots in lower terrain and by 0.69（±1.00） m^2·ha^-1·yr^-1 in the higher non-annual y flooded（NAF） plots, corresponding to an aboveground biomass increase of 0.81（±0.57） and 0.69（±1.58） Mg·ha^-1·yr^-1 in the AF and NAF plots, indicating a recent carbon sink in the biomass. Mean diameter growth rate was 1.8（±0.44） mm·yr^-1 in the AF and 2.0（±0.56） mm·yr^-1 in the NAF plots（corresponding to a coarse wood production of 1.53（±1.29） and 2.02（±0.52） Mg·ha^-1·yr^-1）,indicating no flooding effect on radial growth. Mean mortality rates in the 5-year period were 1.9（±0.37）·yr^-1 in the AF plots and 1.8（±0.87）%·yr^-1 in the NAF plots with no differences along the flooding gradient. Highest mortalities were registered in the AF plots for the 10–20 cm dbh class（2.4%·yr^-1）, likely as a consequence of flooding,and in the NAF plots for the 40–50 cm dbh class（3.0%·yr^-1）, probably mainly caused by ENSO-related ***： We conclude that these drought-affected tropical floodplain forests have a lower standing biomass and aboveground productivity than central Amazonian floodplain forests in more humid climates, and the imprint of the flooding gradient on stand dynamics is relatively weak, which may result from the lower flooding height and the interaction of flooding with low nutrient supply and periodic drought.

关键词： Amazon Diameter growth Dry season Flooding regime Mortality rate Productivity Tree recruitment

Soil carbon and nutrient stocks under Scots pine plantations in comparison to European beech forests: a paired-plot study across forests with different management history and precipitation regimes

在线全文

学校读者我要写书评

暂无评论

Forest Ecosystems 2021年第3期8卷 628-643页

作者： Marco Diers Robert Weigel Heike Culmsee Christoph leuschner Plant Ecology Albrecht-von-Haller-Institute for Plant SciencesUniversity of GoettingenUntere Karspuele 237073 GoettingenGermany Centre of Biodiversity and Sustainable Land Use(CBL) University of GoettingenBuesgenweg 137077 GoettingenGermany

Background:Organic carbon stored in forest soils(SOC)represents an important element of the global C *** is thought that the C storage capacity of the stable pool can be enhanced by increasing forest productivity,but empirical evidence in support of this assumption from forests differing in tree species and productivity,while stocking on similar substrate,is ***:We determined the stocks of SOC and macro-nutrients(nitrogen,phosphorus,calcium,potassium and magnesium)in nine paired European beech/Scots pine stands on similar Pleistocene sandy substrates across a precipitation gradient(560–820mm∙yr−1)in northern Germany and explored the influence of tree species,forest history,climate,and soil pH on SOC and nutrient ***:While the organic layer stored on average about 80%more C under pine than beech,the pools of SOC and total N in the total profile(organic layer plus mineral soil measured to 60 cm and extrapolated to 100 cm)were greater under pine by about 40%and 20%,*** contrasts with a higher annual production of foliar litter and a much higher fine root biomass in beech stands,indicating that soil C sequestration is unrelated to the production of leaf litter and fine roots in these stands on Pleistocene sandy *** pools of available P and basic cations tended to be higher under *** precipitation nor temperature influenced the SOC pool,whereas tree species was a key *** extended data set(which included additional pine stands established more recently on former agricultural soil)revealed that,besides tree species identity,forest continuity is an important factor determining the SOC and nutrient pools of these ***:We conclude that tree species identity can exert a considerable influence on the stocks of SOC and macronutrients,which may be unrelated to productivity but closely linked to species-specific forest management histories,thus masking weaker climate and soil chemistry effects on pool sizes

关键词： Basic cations Fagus sylvatica Forest history Nitrogen Paired plots Pinus sylvestris Productivity effect Soil organic carbon Tree species effect

Androgen receptor expression in clinically localized prostate cancer： immunohistochemistry study and literature review

在线全文

学校读者我要写书评

暂无评论

Asian Journal of Andrology 2008年第6期10卷 855-863页

作者： Yi-Qing Qiu Ivo leuschner Peter Martin Braun Department of Urology the Second Affliated Hospital of Zhejiang University Hangzhou 310009 China Department of Urology and Pediatric Urology Department of Pathology Universitgitsklinikum Schleswig-Holstein Campus Kiel Kiel 24105 Germany

Aim： To evaluate androgen receptor （AR） expression in clinically localized prostate cancer （PCa）. Methods： Specimens were studied from 232 patients who underwent radical prostatectomy for clinically localized prostatic adenocarcinoma without neoadjuvant hormonal therapy or chemotherapy at our institution between November 2001 and June 2005. Immunohistochemical study was performed using an anti-human AR monoclonal antibody AR441. The mean AR density in the hot spots of different histological areas within the same sections were compared and the correlation of malignant epithelial AR density with clinicopathological parameters such as Gleason score, tumor, nodes and metastases （TNM） stage and pre-treatment prostate-specific antigen （PSA） value was assessed. Results： AR immunoreactivity was almost exclusively nuclear and was observed in tumor cells, non-neoplastic glandular epithelial cells and a proportion of peritumoral and interglandular stromal cells. Mean percentage of AR-positive epithelial cells was significantly higher in cancer tissues than that in normal prostate tissues （mean e SD, 90.0% ± 9.3% vs. 85.3% ±9.7%, P 〈 0.001）. The histological score yielded similar results. The percentage ofAR immunoreactive prostatic cancer nuclei and histological score were not correlated with existing parameters such as Gleason score, tumor, nodes and metastases stage and pre-treatment PSA value in this surgically treated cohort. Conclusion： The results of the present study suggest that there may be limited clinical use for determining AR expression （if evaluated in hot spots） in men with localized PCa.

关键词： androgen receptor prostate cancer immunohistochemistry

Response of tree-ring width to climate warming and selective logging in larch forests of the Mongolian Altai

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Plant Ecology 2014年第1期7卷 24-38页

作者： Choimaa Dulamsuren Mookhor khishigjargal Christoph leuschner Markus Hauck Department of Plant Ecology Albrecht von Haller Institute of Plant SciencesGeorg August University of GöttingenUntere Karspüle 237073 GöttingenGermany

Aims The Mongolian Altai is an old settlement area,which is populated by pastoral nomads since 2000–3000 *** in this region(at ca.2300 m a.s.l.)are highly fragmented and border on steppe and alpine grasslands,which are used for mobile livestock *** climate in Central Asia is warming to levels clearly above the global average,which affects the ***,the transition from planned to market economy and the decollectivization of livestock 20 years ago has strongly changed land use practices in Mongolia,especially resulting in an increase in recent logging *** were interested in the question how climate warming and selective logging influence the annual stem growth and the stand *** The impact of climate and land use by the pastoral nomads on the annual stem increment of more than 1800 trees of Siberian larch(Larix sibirica)was *** groups of trees with divergent growth trends depending on the social position and stand history were identified by non-metric multidimensional scaling and analysis of ***-term trends in the annual stem increment were analyzed by establishing separate regional growth curves for trees of different age *** Findings Instrumental climate data substantiate an increase of temperature by 2.1°C since 1940 at constant *** benefit from the increased ***–response analysis revealed that radial stem increment was promoted by the temperature in early summer,but also high precipitation in spring and in the year before tree-ring *** dynamics is also strongly influenced by anthropogenic *** addition to the natural forest dynamics,logging resulted in divergent growth trends within given age classes and habitats(forest interior and forest edge);overall,22 groups of trees with different characteristics in the annual radial stem increment were identified.A tree-ring series-based reconstruction of logging inten

关键词： climate change forest management forest-steppe ecotones Central Asia Larix sibirica

Regeneration of Nothofagus dombeyi(Mirb.)?*** little to moderately disturbed southern beech forests in the Andes of Patagonia(Argentina)

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Forest Ecosystems 2023年第4期10卷 472-482页

作者： Stefan Zerbe Stefanie T.Storz Georg Leitinger Natalia Zoe Joelson José Bava Steffi Heinrichs Christoph leuschner Gabriel Loguercio Alois Simon María F.Urretavizcaya Helge Walentowski Faculty of Agricultural Environmental and Food SciencesFree University of Bozen-Bolzano Department of Ecology University of Innsbruck Faculty of Resource Management HAWK University of Applied Sciences and Arts Department of Plant Ecology and Ecosystem Research Albrecht-von-Haller-Institute for Plant SciencesUniversity of G?ttingen Centro de Investigación y Extensión Forestal Andino Patagónico(CIEFAP) Department of Forest Planning Tyrol Forest Administration Office of the Tyrolean Government

Natural forests and stands subj ected to little to moderate human impact are continuously declining worldwide and with these,their biodiversity and ecosystem *** Nothofagus forests in the south of the South American continent are in a pristine state or only moderately impacted by *** grazing by livestock,in the past and still today often practiced in a non-sustainable way is,however,increasingly under discussion to meet current environmental and socio-economic ***,we investigate the regeneration of Nothofagus dombeyi,a keystone species of the Patagonian Andes,in secondary forests in Argentinian northern Patagonia,particularly addressing the role of disturbance through grazing by livestock at various *** test the hypothesis that the regeneration of this tree species is favored by grazing impact and,thus,disturbance of the herb layer and soil *** support of our hypothesis,Nothofagus dombeyi regeneration was significantly higher in terms of individuals and height classes in moderately grazed *** analysis shows significant positive effects of moderate grazing pressure,herb layer cover,and the occurrence of bare soil on the regeneration of Nothofagus *** results show that an integration of livestock grazing and forest regeneration is possible and that agroforestry systems can be an adequate management option for stakeholders in the region.A grazing management can also be part of a forest fire prevention ***,the regeneration success and grazing pressure should be continuously monitored.

关键词：

The mechanisms of cracks formation of silver-based contact materials under arc and making pressure

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Coal Science & Engineering(China) 2004年第1期10卷 73-77页

作者：郭凤仪陈忠华张玲玲张继华 FW leuschner Department of Electrical Engineering Liaoning Technical University Fuxin 123000 China Department of Electrical Electronics and Computer Engineering University of Pretoria South Africa

The arc erosion experiments on five kinds of silver-based contact materials, AgZnO (10), AgSnO2 (8.5) In2O3 (4), AgCdO (12), AgNi(10), AgWC(12)C(3) were carried out according to different breaking times, breaking currents, and making pressures. Then based on the theoretical analysis and the photographs taken by scanning electronic mi-croscope with EDAX analyzer, the crack morphology was studied scientifically. Three types of cracks, which are cavity cracks, grain boundaries (or phase boundaries) slipping cracks, and thermal stress cracks, were put forward under arc and making pressure through establishing their physical models and discussing their formation mechanisms.

关键词：接触材料银 EDAX 裂纹 AgZnO AgSnO2 In2O3 AgCdO AgNi

在线全文

学校读者我要写书评

暂无评论

经导管主动脉瓣植入术研究进展

临床心血管病杂志 2016年第10期32卷 967-968页

作者：刘坤李裕舒 Emmanuel Chorianopoulos Florian leuschner 华中科技大学附属协和医院心内科华中科技大学同济医学院心血管病研究所武汉430022 Innere MedizinⅢ:kardiologie Angiologie und PneumologieMedizinische KlinikUniversitats Klinikum Heidelberg

随着人口结构的老龄化,主动脉瓣狭窄等心脏瓣膜病的发病率呈上升趋势。近年来,一种新的心血管介入治疗技术——经导管主动脉瓣植入术(TAVR)被临床试验证实其疗效,已被指南推荐治疗不能耐受外科手术或手术高危的严重主动脉瓣狭窄患者。... 详细信息

随着人口结构的老龄化,主动脉瓣狭窄等心脏瓣膜病的发病率呈上升趋势。近年来,一种新的心血管介入治疗技术——经导管主动脉瓣植入术(TAVR)被临床试验证实其疗效,已被指南推荐治疗不能耐受外科手术或手术高危的严重主动脉瓣狭窄患者。随着新一代经导管植入心脏瓣膜系统的开发和TAVR术临床实践的深入,TAVR手术并发症将得到有效的控制,其适应证不断拓宽,给心脏瓣膜病的治疗带来新的突破。

关键词：主动脉瓣狭窄导管植入

Regeneration of Nothofagus dombeyi(Mirb.)Ø*** little to moderately disturbed southern beech forests in the Andes of Patagonia(Argentina)

在线全文

学校读者我要写书评

暂无评论

森林生态系统:英文版 2023年第4期10卷 472-482页

作者： Stefan Zerbe Stefanie T.Storz Georg Leitinger Natalia Zoe Joelson JoséBava Steffi Heinrichs Christoph leuschner Gabriel Loguercio Alois Simon María F.Urretavizcaya Helge Walentowski Faculty of Agricultural Environmental and Food SciencesFree University of Bozen-BolzanoBolzanoItaly Department of Ecology University of InnsbruckInnsbruckAustria Faculty of Resource Management HAWK University of Applied Sciences and ArtsGöttingenGermany Department of Plant Ecology and Ecosystem Research Albrecht-von-Haller-Institute for Plant SciencesUniversity of GöttingenGöttingenGermany Centro de Investigación y Extensión Forestal Andino Patagónico(CIEFAP) EsquelArgentina Department of Forest Planning Tyrol Forest AdministrationOffice of the Tyrolean GovernmentInnsbruckAustria

Natural forests and stands subjected to little to moderate human impact are continuously declining worldwide and with these,their biodiversity and ecosystem *** Nothofagus forests in the south of the South American continent are in a pristine state or only moderately impacted by *** grazing by livestock,in the past and still today often practiced in a non-sustainable way is,however,increasingly under discussion to meet current environmental and socio-economic ***,we investigate the regeneration of Nothofagus dombeyi,a keystone species of the Patagonian Andes,in secondary forests in Argentinian northern Patagonia,particularly addressing the role of disturbance through grazing by livestock at various *** test the hypothesis that the regeneration of this tree species is favored by grazing impact and,thus,disturbance of the herb layer and soil *** support of our hypothesis,Nothofagus dombeyi regeneration was significantly higher in terms of individuals and height classes in moderately grazed *** analysis shows significant positive effects of moderate grazing pressure,herb layer cover,and the occurrence of bare soil on the regeneration of Nothofagus *** results show that an integration of livestock grazing and forest regeneration is possible and that agroforestry systems can be an adequate management option for stakeholders in the region.A grazing management can also be part of a forest fire prevention ***,the regeneration success and grazing pressure should be continuously monitored.

关键词： Agroforestry Disturbance Fire management Forest grazing Forest management Plant traits