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Ecological thresholds and large carnivores conservation: Implications for the Amur tiger and leopard in China
The ecological threshold concept describes how changes in one or more factors at thresholds can result in a large shift in the state of an ecosystem. This concept focuses attention on limiting factors that affect the tolerance of systems or organisms and changes in them. Accumulating empirical evidence for the existence of ecological thresholds has created favorable conditions for practical application to wildlife conservation. Applying the concept has the potential to enhance conservation of two large carnivores, Amur tiger and leopard, and the knowledge gained could guide the construction of a proposed national park. In this review, ecological thresholds that result from considering a paradigm of bottom-up control were evaluated for their potential to contribute to the conservation of Amur tiger and leopard. Our review highlights that large carnivores, as top predators, are potentially affected by ecological thresholds arising from changes in climate (or weather), habitat, vegetation, prey, competitors, and anthropogenic disturbances. What's more, interactions between factors and context dependence need to be considered in threshold research and conservation practice, because they may amplify the response of ecosystems or organisms to changes in specific drivers. Application of the threshold concept leads to a more thorough evaluation of conservation needs, and could be used to guide future Amur tiger and leopard research and conservation in China. Such application may inform the conservation of other large carnivores worldwide
Topological aspect of graphene physics
Topological aspects of graphene are reviewed focusing on the massless Dirac
fermions with/without magnetic field. Doubled Dirac cones of graphene are
topologically protected by the chiral symmetry. The quantum Hall effect of the
graphene is described by the Berry connection of a manybody state by the filled
Landau levels which naturally possesses non-Abelian gauge structures. A generic
principle of the topologically non trivial states as the bulk-edge
correspondence is applied for graphene with/without magnetic field and explain
some of the characteristic boundary phenomena of graphene.Comment: 12 pages, 8 figures. Proceedings for HMF-1
Some integral inequalities on time scales
In this paper, some new integral inequalities on time scales are presented by
using elementarily analytic methods in calculus of time scales.Comment: 8 page
Epitaxial graphene on SiC(0001): More than just honeycombs
The potential of graphene to impact the development of the next generation of
electronics has renewed interest in its growth and structure. The
graphitization of hexagonal SiC surfaces provides a viable alternative for the
synthesis of graphene, with wafer-size epitaxial graphene on SiC(0001) now
possible. Despite this recent progress, the exact nature of the graphene-SiC
interface and whether the graphene even has a semiconducting gap remain
controversial. Using scanning tunneling microscopy with functionalized tips and
density functional theory calculations, here we show that the interface is a
warped carbon sheet consisting of three-fold hexagon-pentagon-heptagon
complexes periodically inserted into the honeycomb lattice. These defects
relieve the strain between the graphene layer and the SiC substrate, while
still retaining the three-fold coordination for each carbon atom. Moreover,
these defects break the six-fold symmetry of the honeycomb, thereby naturally
inducing a gap: the calculated band structure of the interface is
semiconducting and there are two localized states near K below the Fermi level,
explaining the photoemission and carbon core-level data. Nonlinear dispersion
and a 33 meV gap are found at the Dirac point for the next layer of graphene,
providing insights into the debate over the origin of the gap in epitaxial
graphene on SiC(0001). These results indicate that the interface of the
epitaxial graphene on SiC(0001) is more than a dead buffer layer, but actively
impacts the physical and electronic properties of the subsequent graphene
layers
A New Solution of the Yang-Baxter Equation Related to the Adjoint Representation of
A new solution of the Yang-Baxter equation, that is related to the adjoint
representation of the quantum enveloping algebra , is obtained by
fusion formulas from a non-standard solution.Comment: 16 pages (Latex), Preprint BIHEP-TH-93-3
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