维普中文期刊产品整合服务
3099篇 您的检索式:作者名="J Fischer"
    题名 作者 年代 出处 被引量
1On the combined effect of soil fertility and topography on tree growth in subtropical forest ecosystems—a study from SE China显示文摘Aims The aim of our research was to understand small-scale effects of topography and soil fertility on tree growth in a forest biodiversity and ecosystem functioning(BEF)experiment in subtropical SE China.Methods Geomorphometric terrain analyses were carried out at a spatial resolution of 5×5 m.Soil samples of different depth increments and data on tree height were collected from a total of 566 plots(667 m2 each).The soils were analyzed for carbon(soil organic carbon[SOC]),nitrogen,acidity,cation exchange capacity(CEC),exchangeable cations and base saturation as soil fertility attributes.All plots were classified into geomorphological units.Analyses of variance and linear regressions were applied to all terrain,soil fertility and tree growth attributes.Important Findings In general,young and shallow soils and relatively small differences in stable soil properties suggest that soil erosion has truncated the soils to a large extent over the whole area of the experiment.This explains the concurrently increasing CEC and SOC stocks downslope,in hollows and in valleys.However,colluvial,carbon-rich sediments are missing widely due to the convexity of the footslopes caused by uplift and removal of eroded sediments by adjacent waterways.The results showed that soil fertility is mainly influenced by topography.Monte-Carlo flow accumulation(MCCA),curvature,slope and aspect significantly affected soil fertility.Furthermore,soil fertility was affected by the different geomorphological positions on the experimental sites with ridge and spur positions showing lower exchangeable base cation contents,especially potassium(K),due to leaching.This geomorphological effect of soil fertility is most pronounced in the topsoil and decreases when considering the subsoil down to 50 cm depth.Few soil fertility attributes affect tree height after 1-2 years of growth,among which C stocks proved to be most important while pH_(KCl)and CEC only played minor roles.Nevertheless,soil acidity and a high proportion of Al on the exchange complex affected tree height even after only 1-2 years growth.Hence,our study showed that forest nutrition is coupled to a recycling of litter nutrients,and does not only depend on subsequent supply of nutrients from the mineral soil.Besides soil fertility,topography affected tree height.We found that especially MCCA as indicator of water availability affected tree growth at small-scale,as well as aspect.Overall,our synthesis on the interrelation between fertility,topography and tree growth in a subtropical forest ecosystem in SE China showed that topographic heterogeneity lead to ecological gradients across geomorphological positions.In this respect,small-scale soil-plant interactions in a young forest can serve as a driver for the future development of vegetation and biodiversity control on soil fertility.In addition,it shows that terrain attributes should be accounted for in ecological research.Thomas Scholten Philipp Goebes Peter Kühn Steffen Seitz Thorsten Assmann Jürgen Bauhus Helge Bruelheide Francois Buscot Alexandra Erfmeier Markus Fischer Werner Härdtle Jin-Sheng He Keping Ma Pascal A.Niklaus Michael Scherer-Lorenzen Bernhard Schmid Xuezheng Shi Zhengshan Song Goddert von Oheimb Christian Wirth Tesfaye Wubet Karsten Schmidt 2017Journal of Plant Ecology2017,10,1:22
2缺血性脑卒中和出血性脑卒中患者发病前后血压的变化显示文摘《中国高血压防治指南2010》指出,急性脑卒中的血压处理缺乏足够的临床试验证据,参考建议如下:急性脑卒中溶栓前血压应控制在<185/110mm Hg(1mm Hg=0.133kPa)。对急性缺血性脑卒中发病24h内血压升高的患者应谨慎处理,收缩压≥180mm Hg或舒张压≥100mm Hg或伴有严重心功能不全、主动脉夹层、高血压脑病者,一般不予降压。降压的合理目标是24h内血压降低约15%。有高血压病史且正在服用降压药物者,如神经功能平稳,可于脑卒中发病后24h开始使用降压药物。因此,了解脑卒中患者发病前后的血压情况对临床治疗有重要的意义。Fischer等研究者探讨缺血性脑卒中和出血性脑卒中患者发病前后血压的变化情况。结果表明,缺血性脑卒中患者发病后首次测量的收缩压低于出血性脑卒中。与发病前比较,缺血性脑卒中发病后收缩压略升高(约10.6mm Hg),24h内轻度降低(约13.6mm Hg);而出血性脑卒中发病后,收缩压明显升高(约40.7mm Hg),24h内明显下降(约41.1mm Hg)。出血性脑卒中发病前几天及几周的平均收缩压逐渐增加,而缺血性脑卒中无明显变化。出血性脑卒中患者发病3h内的最高收缩压比发病前高50.0 mm Hg,而缺血性脑卒中则低5.2mm Hg。综上所述,与发病前比较,出血性脑卒中发病后收缩压升高,而缺血性脑卒中无明显变化。Fischer U Cooney MT Bull LM Silver LE Chalmers J Anderson CS Mehta Z Rothwell PM 林东杰 叶鹏 2014中华高血压杂志2014,22,4:13
3Pineal clock gene oscillation is disturbed in Alzheimer's disease, due to functional disconnection from the "master clock"显示文摘Wu YH Fischer DF Kalsbcck A Garidou-Boof ML van der Vliet J van Heijningen C Liu RY Zhou JN Swaab DE 2006中国生物学文摘2006,20,9:7
4内皮Notch信号的抑制阻碍脂肪酸转运并导致成年心脏的代谢和血管重塑显示文摘营养成分在被肌肉细胞代谢利用之前通过内皮细胞转运。然而,对于内皮运输过程的调节知之甚少。Notch信号传导是发育过程中代谢和血管生成的关键调控因子。在该研究中,Jabs等研究了成年小鼠内皮Notch信号的遗传和药理学调控如何影响内皮脂肪酸转运、心脏血管生成和心脏功能。刘青 叶鹏 Jabs M Rose AJ Lehmann LH Taylor J Moll I Sijmonsma TP Herberich SE Sauer SW Poschet G Federico G Mogler C Weis EM Augustin HG Yan M Gretz N Schmid RM Adams RH Gr9ne HJ Hell R Okun JG Backs J Nawroth PP Herzig S Fischer A 2018中华高血压杂志2018,26,3:6
5Influence of experimental soil disturbances on the diversity of plants in agricultural grasslands显示文摘Aims and Methods Disturbance is supposed to play an important role for biodiversity and ecosystem stability as described by the intermediate disturbance hypoth-esis(IDH),which predicts highest species richness at intermediate levels of disturbances.In this study,we tested the effects of artificial soil distur-bances on diversity of annual and perennial vascular plants and bryo-phytes in a field experiment in 86 agricultural grasslands differing in land use in two regions of Germany.On each grassland,we implemented four treatments:three treatments differing in application time of soil dis-turbances and one control.One year after experimental disturbance,we recorded vegetation and measured biomass productivity and bare ground.We analysed the disturbance response taking effects of region and land-use-accompanied disturbance regimes into account.Important Findings Region and land-use type strongly determined plant species rich-ness.Experimental disturbances had small positive effects on the species richness of annuals,but none on perennials or bryophytes.Bare ground was positively related to species richness of bryophytes.However,exceeding the creation of 12%bare ground further distur-bance had a detrimental effect on bryophyte species richness,which corresponds to the IDH.As biomass productivity was unaffected by disturbance our results indicate that the disturbance effect on spe-cies richness of annuals was not due to decreased overall produc-tivity,but rather due to short-term lowered inter-and intraspecific competition at the newly created microsites.Generally,our results highlight the importance of soil disturbances for species richness of annual plants and bryophytes in agricultural grasslands.However,most grasslands were disturbed naturally or by land-use practices and our additional experimental soil dis-turbances only had a small short-term effect.Overall,total plant diversity in grasslands seemed to be more limited by the availabil-ity of propagules rather than by suitable microsites for germination.Thus,nature conservation efforts to increase grassland diversity should focus on overcoming propagule limitation,for instance by additional sowing of seeds,while the creation of additional open patches by disturbance might only be appropriate where natural disturbances are scarce.Jörg Müller Johannes Heinze Jasmin Joshi Steffen Boch Valentin H.Klaus Markus Fischer Daniel Prati 2014Journal of Plant Ecology2014,7,6:3
6National Forest Inventories capture the multifunctionality of managed forests in Germany显示文摘Background:Forests perform various important ecosystem functions that contribute to ecosystem services.In many parts of the world,forest management has shifted from a focus on timber production to multi-purpose forestry,combining timber production with the supply of other forest ecosystem services.However,it is unclear which forest types provide which ecosystem services and to what extent forests primarily managed for timber already supply multiple ecosystem services.Based on a comprehensive dataset collected across 150 forest plots in three regions differing in management intensity and species composition,we develop models to predict the potential supply of 13 ecosystem services.We use those models to assess the level of multifunctionality of managed forests at the national level using national forest inventory data.Results:Looking at the potential supply of ecosystem services,we found trade-offs(e.g.between both bark beetle control or dung decomposition and both productivity or soil carbon stocks)as well as synergies(e.g.for temperature regulation,carbon storage and culturally interesting plants)across the 53 most dominant forest types in Germany.No single forest type provided all ecosystem services equally.Some ecosystem services showed comparable levels across forest types(e.g.decomposition or richness of saprotrophs),while others varied strongly,depending on forest structural attributes(e.g.phosphorous availability or cover of edible plants)or tree species composition(e.g.potential nitrification activity).Variability in potential supply of ecosystem services was only to a lesser extent driven by environmental conditions.However,the geographic variation in ecosystem function supply across Germany was closely linked with the distribution of main tree species.Conclusions:Our results show that forest multifunctionality is limited to subsets of ecosystem services.The importance of tree species composition highlights that a lack of multifunctionality at the stand level can be compensated by managing forests at the landscape level,when stands of complementary forest types are combined.These results imply that multi-purpose forestry should be based on a variety of forest types requiring coordinated planning across larger spatial scales.Nadja K.Simons María R.Felipe-Lucia Peter Schall Christian Ammer Jürgen Bauhus Nico Blüthgen Steffen Boch François Buscot Markus Fischer Kezia Goldmann Martin M.Gossner Falk Hänsel Kirsten Jung Peter Manning Thomas Nauss Yvonne Oelmann Rodica Pena Andrea Polle Swen C.Renner Michael Schloter Ingo Schöning Ernst-Detlef Schulze Emily F.Solly Elisabeth Sorkau Barbara Stempfhuber Tesfaye Wubet Jörg Müller Sebastian Seibold Wolfgang W.Weisser 2021Forest Ecosystems2021,8,1:2
7The sepsis-induced increase in muscle proteolysis is blocked by specific proteasome inhibitors显示文摘Hobler S C Tiao G Fischer J E 1998Am J Physiol1998,274,:2
8FOLFIRI plus cetuximab versus FOLFIRI plus bevacizumab as first-line treatment for patients with metastatic colorectal cancer (FIRE-3): a randomised, open-label, phase 3 trial显示文摘Volker Heinemann Ludwig Fischer von Weikersthal Thomas Decker Alexander Kiani Ursula Vehling-Kaiser Salah-Eddin Al-Batran Tobias Heintges Christian Lerchenmüller Christoph Kahl Gernot Seipelt Frank Kullmann Martina Stauch Werner Scheithauer J?rg Hielscher 2014Lancet Oncology2014,,10:2
9Changes in sensory properties and consumer acceptance of reduced fat pork Lyon-style and liver sausages containing inulin and citrus fiber as fat replacers显示文摘Maja Tomaschunas Rebecca Z?rb Jürgen Fischer Ehrhard K?hn J?rg Hinrichs Mechthild Busch-Stockfisch 2013Meat Science2013,,3:2
10作为后牙固定义齿支架材料的新型氧化铈稳定四方晶相氧化锆/氧化铝纳米复合体——修复后1年前瞻性病例系列的初步结果显示文摘目的:检验饰面瓷后.氧化铈稳定四方晶相氧化锆/氧化铝纳米复合体(Ce—TZP/A-纳米复合体)做为后牙三单位固定桥(FDPs)支架的临床效果。材料和方法:将单个前磨牙或磨牙缺失需要单个固定桥修复的8名患者纳入病例研究系列。使用CAD/CAM系统(Hint—Eis)制作8个Ce—TZP/A-纳米复合体FDP支架.在支架表面烧制氧化锆饰面瓷(Vintage ZR.Shofu),树脂粘结剂粘结FDPs。粘结后2周、3个月、6个月、12个月选择USPHS标准对修复体进行评价。比较基牙(实验组)与对侧未治疗牙(对照组)的菌斑指数、探诊出血、牙周袋深度等生物学评价指标。在粘结后即刻以及6个月、12个月随访时进行X线检查。对数据进行统计分析。结果:8个被检测FDPs的平均观测期为128-4-11个月。FDPs的保存率为100%。此外,未见FDPs在技术或生物学方面的并发症。实验组PCR为0.1±01、BOP 0.2±0.2、PPD 2.6±0.8。对照组PCR为0.2±0.2、BOP 0.1±0.1、PPD2.6±0.6。两组间各项均值无显著性差异。结论:修复治疗一年后的结果显示.Ce—TZP/A复合体是一种可靠的支架材料。确认上述结论还需要纳入更多的患者.并进行长期的临床随机对照观察实验。Philipp A Fischer J Hammerle CHF Sailer I 王琳琳(译) 邵龙泉(审) 2010中国口腔医学继续教育杂志2010,,6:2
11Present state of the comparison between radiometric scales based on three primary standards显示文摘STOCK M FISCHER J FRIEDRICH R 1993Metrologia1993,30,:2
12A new sulfur-fluorine compound,sulfur tetrafluoride(preliminary communication)显示文摘Fischer J Jaenckner W 1929Angewandte Chemie1929,42,:1
13Laser-assisted endoscopic Third ventriculostomy: long-term results in a series of 202 patients 显示文摘van Beijnum J Hanlo PW Fischer K 2008Neurosurgery2008,62,2:1
14Neural regulation of airway smooth muscle tone显示文摘Canning B J Fischer A 2001Respir Physiol2001,125,12:1
15Development of high performance multifilamentary Nb-Ti-Ta superconductor for LHC insertion quadrupoles 显示文摘Lee P J Fischer C M Larbalestier D C 1999IEEE Trans Applied Superconductivity1999,9,2:1
16Super-exponential complexity of Presburger arithmetic显示文摘FISCHER M J RABIN M O 1974Complexity of Computation 7 AMS Providence RI1974,1974,:1
17Reducing the peak-to-average power ratio of multicarrier modulation by selected mapping 显示文摘R W Bauml R F H Fischer J B Huber 1996Electronics Letters1996,32,22:1
18Thermogravimetric characteriza- tion of gelcast alumina composites显示文摘Dweck J Fischer R Fischer E 1997Journal of Thermal Analys- is and Calorimetry1997,49,3:1
19Inducible aluminum re- sistance of Acidiphilium cryptum and aluminum tolerance of other acido- philic bacteria显示文摘FISCHER J QUENTMEIER A GANSEL S 2002Archives of Microbiology2002,178,6:1
20Biodegradable magnesium-hydroxyapatite metal matrix composites显示文摘WITTE F FEYERABEND F MAIER P FISCHER J STORMER M BLAWERT C DIETZEL W HORT N 2007Biomaterials2007,28,:1
返回顶部 每页显示:
共155页 首页 上一页 第1页 下一页 末页 /155 跳转

网站首页 | 关于我们 | 联系我们 | 产品服务 | 客服中心 | 广告服务 | 版权声明 | 网站联盟 | 友情链接 | 售卡网点

版权所有© 渝B2-20050021-1 渝公网安备 50019002500403号 违法和不良信息举报中心

互联网出版许可证 新出网证(渝)字10号 全国400电话 - 免长途话费