44,193 research outputs found
New Challenges to Arbitration
[Excerpt] Today we face developments in practically every aspect of our lives portending changes within the next quarter century as great as any we have experienced. Changes in one\u27s own field, as in society in general, are often imperceptible at the time they are occurring. Yet, in looking back over my thirty years of teaching in the field of arbitration, I am struck not only by the major changes which have affected the concepts and practice of arbitration, but also, and more significantly, by the new challenges which are emerging to the whole profession of arbitration as well as to the continued viability of the institution itself
Turbulence as observed by concurrent measurements made at NSSL using weather radar, Doppler radar, Doppler lidar and aircraft
As air traffic increases and aircraft capability increases in range and operating altitude, the exposure to weather hazards increases. Turbulence and wind shears are two of the most important of these hazards that must be taken into account if safe flight operations are to be accomplished. Beginning in the early 1960's, Project Rough Rider began thunderstorm investigations. Past and present efforts at the National Severe Storm Laboratory (NSSL) to measure these flight safety hazards and to describe the use of Doppler radar to detect and qualify these hazards are summarized. In particular, the evolution of the Doppler-measured radial velocity spectrum width and its applicability to the problem of safe flight is presented
Schelling segregation in an open city: a kinetically constrained Blume-Emery-Griffiths spin-1 system
In the 70's Schelling introduced a multi-agent model to describe the
segregation dynamics that may occur with individuals having only weak
preferences for 'similar' neighbors. Recently variants of this model have been
discussed, in particular, with emphasis on the links with statistical physics
models. Whereas these models consider a fixed number of agents moving on a
lattice, here we present a version allowing for exchanges with an external
reservoir of agents. The density of agents is controlled by a parameter which
can be viewed as measuring the attractiveness of the city-lattice. This model
is directly related to the zero-temperature dynamics of the
Blume-Emery-Griffiths (BEG) spin-1 model, with kinetic constraints. With a
varying vacancy density, the dynamics with agents making deterministic
decisions leads to a new variety of "phases" whose main features are the
characteristics of the interfaces between clusters of agents of different
types. The domains of existence of each type of interface are obtained
analytically as well as numerically. These interfaces may completely isolate
the agents leading to another type of segregation as compared to what is
observed in the original Schelling model, and we discuss its possible
socio-economic correlates.Comment: 10 pages, 7 figures, final version accepted for publication in PR
Warped Kaluza-Klein Towers Revisited
Inspired by the warped Randall Sundrum scenario proposed to solve the mass
scale hierarchy problem with a compactified fifth extra dimension, a similar
model with no metric singularities has been elaborated. In this framework, the
Kaluza-Klein reduction equations for a real massless scalar field propagating
in the bulk have been studied carefully from the point of view of hermiticity
so as to formulate in a mathematically rigorous way all the possible boundary
conditions and corresponding mass eigenvalue towers and tachyon states. The
physical masses as observable in our four-dimensional brane are deduced from
these mass eigenvalues depending on the location of the brane on the extra
dimension axis. Examples of mass towers and tachyons and related field
probability densities are presented from numerical computations performed for
some arbitrary choices of the parameters of the model.Comment: 34 pages, 5 figure
Enhancement of mobilities in a pinned multidomain crystal
Mobility properties inside and around degenerate domains of an elastic
lattice partially pinned on a square array of traps are explored by means of a
fully controllable model system of macroscopic particles. We focus on the
different configurations obtained for filling ratios equal to 1 or 2 when the
pinning strength is lowered. These theoretically expected but never observed
configurations are degenerated, which implies the existence of a multidomain
crystal. We show that the distinction between trapped and untrapped particles
that is made in the case of strong pinning is not relevant for such a weaker
pinning. Indeed, one ought to distinguish between particles inside or around
the domains associated to positional degeneracies. The possible consequences on
the depinning dynamics of the lattice are discussed.Comment: 7 pages, 10 figures Version 2 : longer versio
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