866 research outputs found
Genetic variability and differentiation in roe deer (Capreolus capreolus L) of Central Europe
International audienc
Axisymmetric pulse recycling and motion in bulk semiconductors
The Kroemer model for the Gunn effect in a circular geometry (Corbino disks)
has been numerically solved. The results have been interpreted by means of
asymptotic calculations. Above a certain onset dc voltage bias, axisymmetric
pulses of the electric field are periodically shed by an inner circular
cathode. These pulses decay as they move towards the outer anode, which they
may not reach. As a pulse advances, the external current increases continuously
until a new pulse is generated. Then the current abruptly decreases, in
agreement with existing experimental results. Depending on the bias, more
complex patterns with multiple pulse shedding are possible.Comment: 8 pages, 15 figure
New Zealand marine biosecurity: delivering outcomes in a fluid environment
Marine biosecurity, the protection of the
marine environment from impacts of non-indigenous
species, has a high profile in New Zealand largely
associated with a dependence on shipping. The Ministry
of Fisheries is the lead agency for marine
biosecurity and is tasked with managing the risks
posed by pests and non-indigenous marine species.
Much like the terrestrial environment, multiple pathways
provide ample opportunities for new species
to arrive. The Marine Biosecurity Team was established
in 1998, and under the Biodiversity package
delivered by government, has undertaken an ambitious
programme to deliver biosecurity outcomes by
reducing the knowledge gaps and establishing management
frameworks. A Risk Management Framework
aids decision-making and operational planning.
Despite significant progress, a number of gaps have
been identified in our knowledge base, capability,
and capacity that require attention
Free boundary problems describing two-dimensional pulse recycling and motion in semiconductors
An asymptotic analysis of the Gunn effect in two-dimensional samples of bulk
n-GaAs with circular contacts is presented. A moving pulse far from contacts is
approximated by a moving free boundary separating regions where the electric
potential solves a Laplace equation with subsidiary boundary conditions. The
dynamical condition for the motion of the free boundary is a Hamilton-Jacobi
equation. We obtain the exact solution of the free boundary problem (FBP) in
simple one-dimensional and axisymmetric geometries. The solution of the FBP is
obtained numerically in the general case and compared with the numerical
solution of the full system of equations. The agreement is excellent so that
the FBP can be adopted as the basis for an asymptotic study of the
multi-dimensional Gunn effect.Comment: 19 pages, 9 figures, Revtex. To appear in Phys. Rev.
Osteogenesis Imperfecta: The Molecular Basis of Clinical Heterogeneity a
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73685/1/j.1749-6632.1988.tb55324.x.pd
General Strategies for Isolating the Genes Encoding Type I Collagen and for Characterizing Mutations Which Produce Osteogenesis Imperfecta a
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73326/1/j.1749-6632.1988.tb55325.x.pd
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