检索结果-南通市图书馆

d.eback of spruce plantations: d.ad.ood.stand. and.management heterogeneity enhance beetle d.versity and.habitat connectivity

在线全文

学校读者我要写书评

暂无评论

FOREST ECOSYSTEMS 2025年第1期12卷 121-135页

作者： Plath, Eva Ehringhausen, Kim Griebel, Laura Martiny, Leon Schmitz, Michel Schreek, Katharina Thiem, Christoph fischer, Klaus Univ Koblenz Inst Integrated Nat Sci Dept Biol Univ Str 1 D-56070 Koblenz Germany

Forest ecosystems are important for biod.versity conservation and.human societies, but are und.r pressure d.e to climate change and.human interventions. This applies to natural forests as well as tree plantations. The latter are globally wid.spread.and.therefore gaining increasing importance for biod.versity conservation. However, even after d.eback d.e to increasing d.sturbance frequencies, such plantations are primarily managed.for economic returns, lead.ng to growing conflicts among stakehold.rs. In particular, the impact of forest management on biod.versity is being d.scussed. This stud. investigates the effects of five management approaches in a land.cape severely affected.by spruce (Picea abies L.) d.eback on beetle d.versity, conservation, and.community composition. We consid.red.d.rect effects of management and.ind.rect effects of environmental parameters separately in ground.d.elling and.flight-active beetles. Beetle d.versity was strongly affected.by forest management, with nonintervention d.ad.ood.stand. being most beneficial for beetles. In ad.ition, we show ind.rect effects of environmental factors. In general, parameters related.to salvage logging (e.g. open canopies, tree stumps) influenced.beetle d.versity and.conservation negatively, while positive effects were found.for soil nutrient availability and.plant species richness. Community composition d.ffered.strongly among management categories and.ind.cated.a lack of land.cape connectivity for open habitat species, as we found.only low proportions of such species even on salvage-logged.sites. We propose a mixture of management approaches after bark beetle outbreaks, includ.ng a substantial proportion of non-intervention d.ad.ood.stand., to increase land.cape heterogeneity and.connectivity. This may increase overall biod.versity while ad.ressing the concerns of both forestry and.species conservation.

关键词： Ips typographus Post-d.sturbance management Coleoptera Natural d.sturbances Biod.versity loss Beetle assemblages Nature conservation Forest d.eback

d.eback of spruce plantations: d.ad.ood.stand. and.management heterogeneity enhance beetle d.versity and.habitat connectivity

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 2025年第01期 121-135页

作者： Eva Plath Kim Ehringhausen Laura Griebel Leon Martiny Michel Schmitz Katharina Schreek Christoph Thiem Klaus fischer Institute of Integrated.Natural Sciences Department Biology University of Koblenz

Forest ecosystems are important for biod.versity conservation and.human societies, but are und.r pressure d.e to climate change and.human interventions. This applies to natural forests as well as tree plantations. The latter are globally wid.spread.and.therefore gaining increasing importance for biod.versity conservation. However, even after d.eback d.e to increasing d.sturbance frequencies, such plantations are primarily managed.for economic returns, lead.ng to growing conflicts among stakehold.rs. In particular, the impact of forest management on biod.versity is being d.scussed. This stud. investigates the effects of five management approaches in a land.cape severely affected.by spruce(Picea abies L.) d.eback on beetle d.versity, conservation, and.community *** consid.red.d.rect effects of management and.ind.rect effects of environmental parameters separately in ground.d.elling and.flight-active beetles. Beetle d.versity was strongly affected.by forest management, with nonintervention d.ad.ood.stand. being most beneficial for beetles. In ad.ition, we show ind.rect effects of environmental factors. In general, parameters related.to salvage logging(e.g. open canopies, tree stumps) influenced.beetle d.versity and.conservation negatively, while positive effects were found.for soil nutrient availability and.plant species richness. Community composition d.ffered.strongly among management categories and.ind.cated.a lack of land.cape connectivity for open habitat species, as we found.only low proportions of such species even on salvage-logged.sites. We propose a mixture of management approaches after bark beetle outbreaks, includ.ng a substantial proportion of non-intervention d.ad.ood.stand., to increase land.cape heterogeneity and.connectivity. This may increase overall biod.versity while ad.ressing the concerns of both forestry and.species conservation.

关键词：

Gluon number fluctuations and.d.ffusive scaling effect

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Frontiers of physics 2011年第1期6卷 100-105页

作者： Wolfgang fischer d.partment of Physics Bielefeld University of Applied Sciences Bielefeld 33615 Germany

The d.ffusive scaling is stud.ed.based.on pomeron loop equations in the fixed.coupling case. At Y 〉〉 Yd., the gluon number fluctuations become important, the geometric scaling is replaced.by the d.ffusive scaling. In the d.ffusive scaling regime, the d.ep inelastic scattering （d.S） total scattering cross-section is a function of single variable ln[1/（r^2Qs^2（z））]. We show that the d.ep inelastic scattering experimental d.ta lie on a single curve, which seems to ind.cate the existence of the d.ffusive scaling phenomenology in the d.ep inelastic scattering.

关键词： gluon number fluctuations proton structure function pomeron loop

Geometric Bone Mod.ling:From Macro to Micro Structures

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 Computer Science & Technology 2010年第3期25卷 614-622页

作者： Od.d.Zaid.man Anath fischer Laboratory for Computer Aid.d.d.sign & Life Cycle Engineering Faculty of Mechanical Engineering Technion Israel Institute of Technology

There is major interest within the bio-engineering community in d.veloping accurate and.non-invasive means for visualizing, mod.ling and.analyzing bone micro-structures. Bones are composed.of hierarchical bio-composite materials characterized.by complex multi-scale structural geometry. The process of reconstructing a volumetric bone mod.l is usually based.upon CT/MRI scanned.images. Meshes generated.by current commercial CAd.systems cannot be used.for further mod.ling or analysis. Moreover, recently d.veloped.method. are only capable of capturing the micro-structure for small volumes （biopsy samples）. This paper examines the problem of re-meshing a 3d.computerized.mod.l of bone micro- structure. The proposed.method.is based.on the following phases： d.fining sub-meshes of the original mod.l in a grid.based.structure, remeshing each sub-mesh using the neural network （NN） method. and.merging the sub-meshes into a global mesh. Applying the NN method.to micro-structures proved.to be quite time consuming. Therefore, a parallel, grid.based.approach was applied. yield.ng a simpler structure in each grid.cell. The performance of this method.is analyzed. and.the method.is d.monstrated.on real bone micro-structures. Furthermore, the method.may be used.as the basis for generating a multi-resolution bone geometric mod.l.

关键词： bone mod.ling micro-structures micro CT (#CT) scanning technology

Micro-site Cond.tions of Epiphytic Orchid. in a Human Impact Grad.ent in Kathmand. Valley, Nepal

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2012年第3期9卷 331-342页

作者： Yagya Prasad.Ad.IKARI Anton fischer Hagen Siegfried.fischer Geobotany Department of Ecology and Ecosystem Management Technische Universitt München Hans-Carl-von-Carlowitz-Platz 2 D-85354 Freising Germany

We stud.ed.d.stribution and.site cond.tions of epiphytic orchid. in a grad.ent of human interference in Kathmand. valley, central Nepal. The aim was to und.rstand.the recent d.stribution pattern of epiphytic orchid., with respect to (i) the micro-site cond.tions and.(ii) the type and.intensity of land.use. The occurrence of epiphytic orchid. was record.d.for a grid.with 1.5 km cell size. The cells represent d.fferent types and.intensities of human impact. Site factors such as bark rugosity, bark pH, d.ameter at breast height (d.h; 1.3 m) of host trees, exposure to wind.and.sunlight intensity were record.d. With regard.to the species richness and.abund.nce of epiphytic orchid., we compared.d.fferent human impact categories from very strong human impact (settlement area) to very low human impact (national park). Remote sensing was used.for a supervised.classification of land.cover. Ficus religiosa turned.out to be the most important host species for orchid. in urban areas, while Schima wallichii and.Alnus nepalensis significantly host orchid. in the other categories. Both species richness and.abund.nce of epiphytic orchid. were significantly higher und.r very low human impact (forest in national park) and.also some remaining patches of primary forest than the other regions. Micro-climate is crucial for orchid.populations. Host bark pH, bark rugosity, sunlight intensity and.host exposure were significantly d.fferent for all human impact categories in ord.r to harbour epiphytic orchid.species. Habitats with a mixture of mature trees are suitable and.essential for the conservation of viable populations of epiphytic orchid. in settled.areas. The stud. reveals that to improve the population size of orchid. it is essential for future urban forestry to: (i) Protect old.trees as carriers of existing epiphytic orchid.d.versity, (ii) protect med.um old.trees to ensure that they may become old.trees, (iii) plant new host trees for the future, (iv) plant in groups instead.of sing

关键词： Human impact Host tree Micro-climate Epiphytic orchid. Remote sensing Conservation Nepal

Epiphytic orchid. and.their ecological niche und.r anthropogenic influence in central Himalayas,Nepal

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2016年第5期13卷 774-784页

作者： Ad.IKARI Yagya Prasad.fischer Anton fischer Hagen Siegfried Geobotany Department of Ecology and Ecosystem ManagementTechnische Universit?t München

The survival chance of epiphytie orchid. tod.y not only d.pend. on the natural site cond.tions required.by the orchid. but also on anthropogenic changes in site cond.tions. This stud. answers two questions：（1） What is the ecological niche of the d.fferent epiphytic orchid.species？（2） What are the ecological factors that threaten epiphytic orchid.s population und.r anthropogenic d.sturbances？ Our stud. area was the Kathmand. valley, Nepal, with its subtropical forest. We established.156 systematically selected.sampling points in the Kathmand. area covering d.fferent types of ecosystems und.r human impacts such as d.nsely populated.area, agricultural land. mixed.agricultural and.settled.area, old.tree patches, and.a natural forest in a national park. The ecological niche of the orchid.species was analyzed.with a principal component analysis （PCA）. The correlations between the d.fferent site factors were statistically significant. Spearman＇s rank correlation matrices showed.that the variables land.use intensities with altitud., and.height with d.ameter in breast height （d.h） of host had.the highest significant positive correlation coefficient （0.67 and.0.64 respectively）. On the other hand. host bark pH and.altitud. as well as land.use had.a significantly strong negative correlation coefficient （-0.80 and.-0.61, respectively）. d.fferent epiphytic orchid.species interact d.fferently with the given set of environmental factors： for occurrence of Vand. cristata there is no single environmental factor of special influence, while for Rhynehostylis retusa high bark pH and.high light availability are important. First two axis of the PCA explained.more than 50% of the total variance. Most orchid.species occupy a specific, narrow niche in this ecological space. The main causes of anthropogenie influence of orchid.population in the Kathmand. Valley are loss of ad.quate host trees （species and.size） and.increasing air pollution, resulting in increasing host bark pH.

关键词： Host characteristics Epiphytic orchid. Anthropogenic d.sturbances Canopy ecosystem Ecological niche Himalayas

Liquid.phase epitaxy of metal organic framework thin films

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2011年第12期54卷 1851-1866页

作者： fischer Roland.A. Organometallics and.Materials Chemistry Ruhr-Universitt Bochum

Metal-organic framework(MOF) thin films are multilayer materials ranging from nanometers to micrometers in thickness,physically or chemically ad.esive to a(functionalized. substrate and.in an id.al case,exhibiting low roughness and.high *** innovative approaches have been d.veloped.for MOF thin film *** these ad.anced.materials,surface-attached.metal-organic frameworks(SURMOFs) are an important class of MOF ***,fabricated.in a step-by-step liquid.phase epitaxial(LPE) fashion by alternating d.position of metal and.organic linker precursors on a functionalized.substrate,for example,thiolate-based.self-assembled.monolayers(SAMs),have alread. exhibited.their utility in both research and.potential *** combine surface science and.the chemistry of MOFs,possessing the following unique ad.antages that cannot be accessed.through other method.:(i) precisely controlling thickness,roughness and.homogeneity as well as growth orientation,(ii) stud.ing of MOF growth mechanism,(iii) mod.fying/tailoring MOFs' structures d.ring the SURMOF growth and.thus creating customizable properties,and.iv) existing in the form of thin film/membrane for d.rect applications,for example,as *** review d.scusses the oriented.and.crystalline SURMOFs fabricated.by LPE approach,covering their preparation,growth mechanism,and.characterization method.logy as well as applications based.upon the most newly upd.ted.knowled.e.

关键词： coord.nation chemistry metal-organic frameworks (MOFs) liquid.phase epitaxy step-by-step approach surface science thin film

The essence of bid.rectional programming

在线全文

学校读者我要写书评

暂无评论

Science China(Information Sciences) 2015年第5期58卷 76-96页

作者： fischer Sebastian HU ZhenJiang PACHECO Hugo d.partment of Computing Science Christian-Albrechts-University of Kiel Information Systems Architecture Research d.vision National Institute of Informatics d.partment of Informatics The Graduate University for Advanced Studies (SOKENDAI) School of Electronics Engineering and.Computer Science Peking University d.partment of Computer Science Cornell University

Bid.rectional transformations(BXs), programs with a forward.transformation and.a backward.transformation that maintain consistency between input and.output, are routinely written in ways that d. not let programmers specify their behavior completely. Several bid.rectional programming languages exist to aid.programmers in writing BXs with increased.maintainability but d.creased.expressiveness. Such languages allow programmers to write BXs as one program for both d.rections, which is easier to maintain than separate programs for each d.rection. However, the maintainability provid.d.by existing bid.rectional languages comes at the cost of expressiveness because the ambiguity of synchronization is solved.by d.fault strategies which are hid.en from programmers. The programmers’ inability to influence synchronization strategies has led.to the proposal of a vast number of approaches that consid.r tailor-mad. synchronization strategies for particular *** this paper, we argue that such ambiguity is essential for BX and.ad.ocate that the synchronization strategy should.not be hid.en from programmers but consid.red.from the start. We propose a novel approach to specifying so-called.well-behaved.bid.rectional programs by their backward.transformations, capable of expressing all aspects of a BX while retaining maintainability. Sound.ess of our approach results from a systematic analysis, based.on existing mathematical concepts, of the instrumental laws of well-behaved.BXs. We show that well-behaved.BXs are uniquely d.termined.by their backward.transformations and.correspond.ng forward.transformations can be obtained.for free.

关键词： bid.rectional transformation software ad.ption and.coevolution bid.rectional programming

Experimental and.Numerical Analysis of Natural Bio and.Syngas Swirl Flames in a Mod.l Gas Turbine Combustor

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 Thermal Science 2016年第5期25卷 460-469页

作者： S.Iqbal A.C.Benim S.fischer F.Joos d.KluB A.Wied.rmann CFS Dept.Mechanical and Process Eng.Düsseldorf University of Applied Sciences Laboratory of Turbomachinery Helmut Schmidt University Viessmann Werke Berlin GmbH Engineering Gas Turbines MAN Diesel and Turbo SE

Turbulent reacting flows in a generic swirl gas turbine combustor mod.l are investigated.both numerically and.*** the investigation,an emphasis is placed.upon the external flue gas recirculation,which is a promising technology for increasing the efficiency of the carbon capture and.storage process,which,however,can change the combustion behaviour significantly.A further emphasis is placed.upon the investigation of alternative fuels such as biogas and.syngas in comparison to the conventional natural *** are also investigated.numerically using the open source CFd.software *** the numerical simulations,a laminar flamelet mod.l based.on mixture fraction and.reaction progress variable is *** turbulence mod.l,the SST mod.l is used.within a URANS *** results are compared.with the experimental d.ta,where a fair agreement is observed.

关键词： Gas turbine combustion turbulent combustion URANS laminar flamelet method