3,093 research outputs found
Recent Developments in Trade Between the U.S. and the P.R.C.: A Legal and Economic Perspective
This paper presents the life story of a single small-business owner of immigrant background who wants his companyto grow. His business strategies are analysed both as a part of his own biographical work, and as they wereinfluenced and framed by broader political, economic and social processes. It is shown how his own personalqualities in combination with opportunity structures in the local market provided favourable conditions for hisbreak-in. Breaking out, however, seems to be presented with different types of barriers, such as lack of access tocapital, discrimination, and the fact that new markets may consist of different sorts of network that are in its turnmore difficult for new actors to enter. But even if newcomers often find these barriers difficult for to overcome,individuals are not just passive objects but also have the opportunity to realize their lives according to their own lifeplans
Stability of 2pi domain walls in ferromagnetic nanorings
The stability of 2pi domain walls in ferromagnetic nanorings is investigated
via calculation of the minimum energy path that separates a 2pi domain wall
from the vortex state of a ferromagnetic nanoring. Trapped domains are stable
when they exist between certain types of transverse domain walls, i.e., walls
in which the edge defects on the same side of the magnetic strip have equal
sign and thus repel. Here the energy barriers between these configurations and
vortex magnetization states are obtained using the string method. Due to the
geometry of a ring, two types of 2pi walls must be distinguished that differ by
their overall topological index and exchange energy. The minimum energy path
corresponds to the expulsion of a vortex. The energy barrier for annihilation
of a 2pi wall is compared to the activation energy for transitions between the
two ring vortex states.Comment: 4 pages, 2 figure
Fluctuation Bounds For Interface Free Energies in Spin Glasses
We consider the free energy difference restricted to a finite volume for
certain pairs of incongruent thermodynamic states (if they exist) in the
Edwards-Anderson Ising spin glass at nonzero temperature. We prove that the
variance of this quantity with respect to the couplings grows proportionally to
the volume in any dimension greater than or equal to two. As an illustration of
potential applications, we use this result to restrict the possible structure
of Gibbs states in two dimensions.Comment: 19 pages, 0 figure
Asymptotic Exit Location Distributions in the Stochastic Exit Problem
Consider a two-dimensional continuous-time dynamical system, with an
attracting fixed point . If the deterministic dynamics are perturbed by
white noise (random perturbations) of strength , the system state
will eventually leave the domain of attraction of . We analyse the
case when, as , the exit location on the boundary
is increasingly concentrated near a saddle point of the
deterministic dynamics. We show that the asymptotic form of the exit location
distribution on is generically non-Gaussian and asymmetric,
and classify the possible limiting distributions. A key role is played by a
parameter , equal to the ratio of the stable
and unstable eigenvalues of the linearized deterministic flow at . If
then the exit location distribution is generically asymptotic as
to a Weibull distribution with shape parameter , on the
length scale near . If it is generically
asymptotic to a distribution on the length scale, whose
moments we compute. The asymmetry of the asymptotic exit location distribution
is attributable to the generic presence of a `classically forbidden' region: a
wedge-shaped subset of with as vertex, which is reached from ,
in the limit, only via `bent' (non-smooth) fluctuational paths
that first pass through the vicinity of . We deduce from the presence of
this forbidden region that the classical Eyring formula for the
small- exponential asymptotics of the mean first exit time is
generically inapplicable.Comment: This is a 72-page Postscript file, about 600K in length. Hardcopy
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