1,659 research outputs found
Invasive species management in two-patch environments: Agricultural damage control in the raccoon (procyon lotor) problem, Hokkaido, Japan
We develop discrete-time models for analyzing the long run equilibrium outcomes on invasive species management in two-patch environments with migration. In particular, the focus is upon a situation where removal operations for invasive species are implemented only in one patch (controlled patch). The new features of the model are that (i) asymmetry in density dependent migration is considered, which may originate from impact of harvesting as well as heterogeneous habitat conditions, and (ii) the effect of density-dependent catchability is well-taken to account for the nature that required effort level to remove one individual may rise as the existing population decreases. The model is applied for agricultural damage control in the raccoon problem that has occurred in Hokkaido, Japan. Numerical illustration demonstrates that the long run equilibrium outcomes highly depend on the degree of asymmetry in migration as well as the sensitivity of catchability in response to a change in the population size of invasive species. Furthermore, we characterize the conditions under which the economically optimal effort levels are qualitatively affected by the above two factors and aiming at local extermination of invasive species in controlled patch is justified.catchability, meta-population, local extermination, removal effort, density dependent migration
Variational problems for the system of nonlinear Schr\"odinger equations with derivative nonlinearities
We consider the Cauchy problem of the system of nonlinear Schr\"odinger
equations with derivative nonlinearlity. This system was introduced by
Colin-Colin (2004) as a model of laser-plasma interactions. We study existence
of ground state solutions and the global well-posedness of this system by using
the variational methods. We also consider the stability of traveling waves for
this system. These problems are proposed by Colin-Colin as the open problems.
We give a subset of the ground-states set which satisfies the condition of
stability. In particular, we prove the stability of the set of traveling waves
with small speed for -dimension.Comment: Introduction is modified and references are update
Structure of Lambda(1405) and threshold behavior of piSigma scattering
The scattering length and effective range of the piSigma channel are studied
in order to characterize the strangeness S=-1 meson-baryon scattering and the
Lambda(1405) resonance. We examine various off-shell dependence of the
amplitude in dynamical chiral models to evaluate the threshold quantities with
the constraint at the KbarN threshold. We find that the piSigma threshold
parameters are important to the structure of the Lambda(1405) resonance and
provide further constraints on the subthreshold extrapolation of the KbarN
interaction.Comment: 20 pages, 4 figures, with corrections made after referring proces
A study on device characterization of polycrystalline-silicon thin-film transistors
Thesis (Ph. D. in Engineering)--University of Tsukuba, (A), no. 5285, 2010.3.25Includes bibliographical reference
The importance of C-terminal residues of vertebrate and invertebrate tachykinins for their contractile activities in gut tissues
AbstractThe C-terminal residues of mammalian tachykinins and urechistachykinins (Uru-TKs), tachykinin-related peptides of echiuroid worm origin, were substituted for each other. Their contractile effects were assayed on the cockroach hindgut and the guinea pig ileum. [Met10] substitution of Uru-TKs caused a 1000 times lower activity on the hindgut, but a 1000 times higher activity on the ileum. In contrast, [Arg11]substance P (SP) was 100 times more and 400 times less potent than SP on the hindgut and ileum, respectively. A SP antagonist blocked these Uru-TK activities on the hindgut. These results demonstrated that the C-terminal Met-NH2 is necessary for ileum contraction and the Arg-NH2 is required for hindgut contraction, which was caused by binding to the cockroach’s neurokinin-like receptor
Treatment of Large Liver Cyst Evaluated with CA19-9 in the Cystic Fluid
A middle-aged woman was admitted with a diagnosis of liver cysts. The patient was symptomatic and was
treated by injecting absolute ethanol into the largest cyst every week, but the secretion from the cyst
persisted. The patient was then treated by absolute ethanol injection every day with good results.
CA 19-9 was measured in the cystic fluid. The secretion was related to CA 19-9 activity
Modulation of domain wall dynamics in TbFeCo single layer nanowire
We demonstrate the possibility to write and modulate the magnetic domain
walls in a TbFeCo single layer nanowire (300 nm width, 150 m length). To
realize this, a tiny magnetic domain was nucleated by an Oersted field produced
by a 1.6 MHz pulse current (35 mA in amplitude, 5-40 ns in length) crossed the
wire. To write the wall to the wire, a DC current was used to drive the
nucleated domain (with two walls in two sides) to the wire in accordance with
spin-transfer torque mechanism. A critical current density of was required to control the motion of the walls in
the wire. It was found that the size of the domain moving in the wire could be
adjusted by either external field or the length of the nucleated pulse current.
This could be considered as an important note for writing process in domain
wall spin-torque devices, especially, memory elements.Comment: 14 pages, 5 figure
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