580 research outputs found
Planar revolute-coupled kinematic chains in critical configurations and their duals
The motivation for studies of dual coupling
networks is explained and a definition is suggested for duality.
Dual couplings are defined and several couplings dual
with the revolute coupling are described. Six linkages, instantaneously
in a critical configuration, provide examples.
The consequences of these critical configurations are explored
for both the linkages and the coupling networks that
are dual with them
Quantum Vacuum Instability Near Rotating Stars
We discuss the Starobinskii-Unruh process for the Kerr black hole. We show
how this effect is related to the theory of squeezed states. We then consider a
simple model for a highly relativistic rotating star and show that the
Starobinskii-Unruh effect is absent.Comment: 17 Pages, (accepted by PRD), (previously incorrect header files have
been corrected
Optimal Management of Severe/Refractory Asthma
Asthma is a chronic inflammatory disease of the airways, affecting approximately 300 million people worldwide. Asthma results in airway hyperresponsiveness, leading to paroxysmal symptoms of wheeze, cough, shortness of breath, and chest tightness. When these symptoms remain uncontrolled, despite treatment with high doses of inhaled and ingested corticosteroids, asthmatic patients are predisposed to greater morbidity and require more health care support. Treating patients with severe asthma can be difficult and often poses a challenge to physicians when providing ongoing management. This clinical review aims to discuss the definition, prevalence and evaluation of severe asthmatics, and provides a review of the existing pharmacologic and non-pharmacologic treatment options
Beyond Gross-Pitaevskii:local density vs. correlated basis approach for trapped bosons
We study the ground state of a system of Bose hard-spheres trapped in an
isotropic harmonic potential to investigate the effect of the interatomic
correlations and the accuracy of the Gross-Pitaevskii equation. We compare a
local density approximation, based on the energy functional derived from the
low density expansion of the energy of the uniform hard sphere gas, and a
correlated wave function approach which explicitly introduces the correlations
induced by the potential. Both higher order terms in the low density expansion,
beyond Gross-Pitaevskii, and explicit dynamical correlations have effects of
the order of percent when the number of trapped particles becomes similar to
that attained in recent experiments.Comment: Revtex, 2 figure
Beyond Gross-Pitaevskii:local density vs. correlated basis approach for trapped bosons
We study the ground state of a system of Bose hard-spheres trapped in an
isotropic harmonic potential to investigate the effect of the interatomic
correlations and the accuracy of the Gross-Pitaevskii equation. We compare a
local density approximation, based on the energy functional derived from the
low density expansion of the energy of the uniform hard sphere gas, and a
correlated wave function approach which explicitly introduces the correlations
induced by the potential. Both higher order terms in the low density expansion,
beyond Gross-Pitaevskii, and explicit dynamical correlations have effects of
the order of percent when the number of trapped particles becomes similar to
that attained in recent experiments.Comment: Revtex, 2 figure
Modulation of aggression in male mice: influence of group size and cage size
Aggression in group-housed male mice is known to be influenced by both cage size and group size. However, the interdependency of these two parameters has not been studied yet. In this study, the level of aggression in groups of three, five, or eight male BALB/c mice housed in cages with a floor size of either 80 or 125 cm2/animal was estimated weekly after cage cleaning for a period of 14 weeks. Furthermore, urine corticosterone levels, food and water intake, body weight, and number of wounds were measured weekly. At the end of the experiment, tyrosine hydroxylase (TH) activity, testosterone levels, and weight of spleen, thymus, testes, and seminal vesicles were determined. Results indicate a moderate increase of intermale aggression in larger cages when compared to the smaller cages. Aggression in groups of eight animals was considerably higher than in groups of three animals. The increase of agonistic behavior was observed both in dominant and subordinate animals. Physiological parameters indicate differences in stress levels between dominant and subordinate animals. It is concluded that aggressive behavior in group-housed male BALB/c mice is best prevented by housing the animals in small groups of three to five animals, while decreasing floor size per animal may be used as a temporary solution to decrease high levels of aggression in an existing social group.
Generalised second law of thermodynamics for interacting dark energy in the DGP brane world
In this paper, we investigate the validity of the generalized second law of
thermodynamics (GSLT) in the DGP brane world when universe is filled with
interacting two fluid system: one in the form of cold dark matter and other is
holographic dark energy. The boundary of the universe is assumed to be enclosed
by the dynamical apparent horizon or the event horizon. The universe is chosen
to be homogeneous and isotropic FRW model and the validity of the first law has
been assumed here
Voltage-tunable singlet-triplet transition in lateral quantum dots
Results of calculations and high source-drain transport measurements are
presented which demonstrate voltage-tunable entanglement of electron pairs in
lateral quantum dots. At a fixed magnetic field, the application of a
judiciously-chosen gate voltage alters the ground-state of an electron pair
from an entagled spin singlet to a spin triplet.Comment: 8.2 double-column pages, 10 eps figure
In-medium relativistic kinetic theory and nucleon-meson systems
Within the model of coupled nucleon-meson systems, a
generalized relativistic Lenard--Balescu--equation is presented resulting from
a relativistic random phase approximation (RRPA). This provides a systematic
derivation of relativistic transport equations in the frame of nonequilibrium
Green's function technique including medium effects as well as flucuation
effects. It contains all possible processes due to one meson exchange and
special attention is kept to the off--shell character of the particles. As a
new feature of many particle effects, processes are possible which can be
interpreted as particle creation and annihilation due to in-medium one meson
exchange. In-medium cross sections are obtained from the generalized derivation
of collision integrals, which possess complete crossing symmetries.Comment: See nucl-th/9310032 for revised version which the authors
incompetently resubmitted rather than correctly replacing thi
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