13,387 research outputs found
Short-term effects of new universities on regional innovation
This paper analyzes empirically the channels through which university research affects industry innovation. We examine how the opening of new science, medicine and engineering departments in Italy during 1985-2000 affected regional innovation systems. We find that creation of a new university department increased regional innovation activity 3-4 years later. On average, an opening of a new department in a region has led to a ten percent change in the number of patents filed by regional firms. Given that this effect occurs within the first half decade of the appearance of a new department, it cannot be ascribed to improvements in the quality and quantity of graduates. At the same time, traditional measures of academic research activity can explain only around 30 percent of this effect.Innovation, Academic Research, R&D, Universities, University-Industry Linkages, Technology Transfer, Regional Innovation Systems.
Size effects and dislocation patterning in two-dimensional bending
We perform atomistic Monte Carlo simulations of bending a Lennard-Jones
single crystal in two dimensions. Dislocations nucleate only at the free
surface as there are no sources in the interior of the sample. When
dislocations reach sufficient density, they spontaneously coalesce to nucleate
grain boundaries, and the resulting microstructure depends strongly on the
initial crystal orientation of the sample. In initial yield, we find a reverse
size effect, in which larger samples show a higher scaled bending moment than
smaller samples for a given strain and strain rate. This effect is associated
with source-limited plasticity and high strain rate relative to dislocation
mobility, and the size effect in initial yield disappears when we scale the
data to account for strain rate effects. Once dislocations coalesce to form
grain boundaries, the size effect reverses and we find that smaller crystals
support a higher scaled bending moment than larger crystals. This finding is in
qualitative agreement with experimental results. Finally, we observe an
instability at the compressed crystal surface that suggests a novel mechanism
for the formation of a hillock structure. The hillock is formed when a high
angle grain boundary, after absorbing additional dislocations, becomes unstable
and folds to form a new crystal grain that protrudes from the free surface.Comment: 15 pages, 8 figure
Controllable binding of polar molecules and meta-stability of 1-D gases with attractive dipole forces
We explore one-dimensional (1-D) samples of ultracold polar molecules with
attractive dipole-dipole interactions and show the existence of a repulsive
barrier due to a strong quadrupole interaction between molecules. This barrier
can stabilize a gas of ultracold KRb molecules and even lead to long-range
wells supporting bound states between molecules. The properties of these wells
can be controlled by external electric fields, allowing the formation of long
polymer-like chains of KRb, and studies of quantum phase transitions by varying
the effective interaction between molecules. We discuss the generalization of
those results to other systems
The thermal Hall effect of spin excitations in a Kagome magnet
At low temperatures, the thermal conductivity of spin excitations in a
magnetic insulator can exceed that of phonons. However, because they are charge
neutral, the spin waves are not expected to display a thermal Hall effect in a
magnetic field. Recently, this semiclassical notion has been upended in quantum
magnets in which the spin texture has a finite chirality. In the Kagome
lattice, the chiral term generates a Berry curvature. This results in a thermal
Hall conductivity that is topological in origin. Here we report
observation of a large in the Kagome magnet Cu(1-3, bdc) which
orders magnetically at 1.8 K. The observed undergoes a remarkable
sign-reversal with changes in temperature or magnetic field, associated with
sign alternation of the Chern flux between magnon bands. We show that thermal
Hall experiments probe incisively the effect of Berry curvature on heat
transport.Comment: 6 pages, 3 figure
Description of nuclear systems with a self-consistent configuration-mixing approach. I: Theory, algorithm, and application to the C test nucleus
Although self-consistent multi-configuration methods have been used for
decades to address the description of atomic and molecular many-body systems,
only a few trials have been made in the context of nuclear structure. This work
aims at the development of such an approach to describe in a unified way
various types of correlations in nuclei, in a self-consistent manner where the
mean-field is improved as correlations are introduced. The goal is to reconcile
the usually set apart Shell-Model and Self-Consistent Mean-Field methods. This
approach is referred as "variational multiparticle-multihole configuration
mixing method". It is based on a double variational principle which yields a
set of two coupled equations that determine at the same time the expansion
coefficients of the many-body wave function and the single particle states. The
formalism is derived and discussed in a general context, starting from a
three-body Hamiltonian. Links to existing many-body techniques such as the
formalism of Green's functions are established. First applications are done
using the two-body D1S Gogny effective force. The numerical procedure is tested
on the C nucleus in order to study the convergence features of the
algorithm in different contexts. Ground state properties as well as
single-particle quantities are analyzed, and the description of the first
state is examined. This study allows to validate our numerical algorithm and
leads to encouraging results. In order to test the method further, we will
realize in the second article of this series, a systematic description of more
nuclei and observables obtained by applying the newly-developed numerical
procedure with the same Gogny force. As raised in the present work,
applications of the variational multiparticle-multihole configuration mixing
method will however ultimately require the use of an extended and more
constrained Gogny force.Comment: 22 pages, 18 figures, accepted for publication in Phys. Rev. C. v2:
minor corrections and references adde
The Value of Terroir: Hedonic Estimation of Vineyard Sale Prices
We examine the value of terroir, which refers to the special characteristics of a place that impart unique qualities to the wine produced. We do this by conducting a hedonic analysis of vineyard sales in the Willamette Valley of Oregon to ascertain whether site attributes, such as slope, aspect, elevation, and soil types, or designated appellations are more important determinants of price. We find that prices are strongly determined by sub-AVA appellation designations, but not by specific site attributes. These results indicate that the concept of terroir matters economically, although the reality of terroir--as proxied for by locational attributes--is not significant.
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