24,106 research outputs found
Utilizing Community Resources to Reduce the Presence of Type 2 Diabetes in Rural Youth
The purpose of this study was to implement a program designed to promote diabetes prevention activities among preadolescents in a rural southern setting using a day camp intervention. Participants in the study were eleven youth from a rural Alabama county who participated in a week-long half-day camp administered by local and community volunteers. Change scores were used to compare pre- to post- to follow-up measures for camp participant responses. Program results consistently demonstrated that the day camp was theoretically sound and that program activities positively impacted behavioral antecedents. This study demonstrated the feasibility of conducting a diabetes prevention day camp in a rural environment. Insights from this intervention can assist planners in rural environments to tailor similar initiatives in rural settings. Given the complicated nature of behavior change, a day camp approach of this length does not modify the behaviors of participants. Behavior changes may take considerably longer to initiate
New simple explicit solutions of perfect fluid hydrodynamics and phase-space evolution
New exact solutions of relativistic perfect fluid hydrodynamics are
described, including the first family of exact rotating solutions. The method
used to search for them is an investigation of the relativistic hydrodynamical
equations and the collisionless Boltzmann equation. Possible connections to the
evolution of hot and dense partonic matter in heavy-ion collisions is
discussed.Comment: 7 pages, 2 figures, two column format. First version substantially
rewritten, typos corrected. Results unchange
Oscillator Models of the Solar Cycle and the Waldmeier Effect
We study the behaviour of the van der Pol oscillator when either its damping
parameter or its nonlinearity parameter is subject to additive or
multiplicative random noise. Assuming various power law exponents for the
relation between the oscillating variable and the sunspot number, for each case
we map the parameter plane defined by the amplitude and the correlation time of
the perturbation and mark the parameter regime where the sunspot number
displays solar-like behaviour. Solar-like behaviour is defined here as a good
correlation between the rise rate and cycle amplitude {\it and} the lack of a
good correlation between the decay rate and amplitude, together with
significant (\ga 10\,%) r.m.s. variation in cycle lengths and cycle
amplitudes. It is found that perturbing alone the perturbed van der Pol
oscillator does not show solar-like behaviour. When the perturbed variable is
, solar-like behaviour is displayed for perturbations with a correlation
time of about 3--4 years and significant amplitude. Such studies may provide
useful constraints on solar dynamo models and their parameters.Comment: 4 pages, 2 figure
Anomalous diffusion of pions at RHIC
After pointing out the difference between normal and anomalous diffusion, we
consider a hadron resonance cascade (HRC) model simulation for particle
emission at RHIC and point out, that rescattering in an expanding hadron
resonance gas leads to a heavy tail in the source distribution. The results are
compared to recent PHENIX measurements of the tail of the particle emitting
source in Au+Au collisions at RHIC. In this context, we show, how can one
distinguish experimentally the anomalous diffusion of hadrons from a second
order QCD phase transition.Comment: 12 pages, 26 figures. Presented by T. Csorgo at the 2nd Workshop on
Particle Femtoscopy and Correlations - WPCF in Sao Paulo, sept 2006.
Brazilian Journal of Physics in press, minor misprints fixe
Oil Price Fluctuations and their Impact on the Macroeconomic Variables of Kuwait: A Case Study Using a VAR Model
Simple solutions of fireball hydrodynamics for rotating and expanding triaxial ellipsoids and final state observables
We present a class of analytic solutions of non-relativistic fireball
hydrodynamics for a fairly general class of equation of state. The presented
solution describes the expansion of a triaxial ellipsoid that rotates around
one of the principal axes. We calculate the hadronic final state observables
such as single-particle spectra, directed, elliptic and third flows, as well as
HBT correlations and corresponding radius parameters, utilizing simple analytic
formulas. We call attention to the fact that the final tilt angle of the
fireball, an important observable quantity, is not independent on the exact
definition of it: one gets different angles from the single-particle spectra
and from HBT measurements. Taken together, it is pointed out that these
observables may be sufficient for the determination of the magnitude of the
rotation of the fireball. We argue that observing this rotation and its
dependence on collision energy would reveal the softness of the equation of
state. Thus determining the rotation may be a powerful tool for the
experimental search for the critical point in the phase diagram of strongly
interacting matter.Comment: 17 pages, 12 figure panel
A new family of exact and rotating solutions of fireball hydrodynamics
A new class of analytic, exact, rotating, self-similar and surprisingly
simple solutions of non-relativistic hydrodynamics are presented for a
three-dimensionally expanding, spheroidally symmetric fireball. These results
generalize earlier, non-rotating solutions for ellipsoidally symmetric
fireballs with directional, three-dimensional Hubble flows. The solutions are
presented for a general class of equations of state that includes the lattice
QCD equations of state and may feature inhomogeneous temperature and
corresponding density profiles.Comment: Dedicated to T. Kodama on the occasion of his 70th birthday. 15
pages, no figures. Accepted for publication at Phys. Rev. C. Minor rewritings
from previous versio
A New Family of Simple Solutions of Perfect Fluid Hydrodynamics
A new class of accelerating, exact and explicit solutions of relativistic
hydrodynamics is found - more than 50 years after the previous similar result,
the Landau-Khalatnikov solution. Surprisingly, the new solutions have a simple
form, that generalizes the renowned, but accelerationless, Hwa-Bjorken
solution. These new solutions take into account the work done by the fluid
elements on each other, and work not only in one temporal and one spatial
dimensions, but also in arbitrary number of spatial dimensions. They are
applied here for an advanced estimation of initial energy density and life-time
of the reaction in ultra-relativistic heavy ion collisions.Comment: 10 pages, 5 figures. EOS is generalized to include a bag constant,
clarity of the presentation is improved and a misprinted label is corrected
in Fig. 2.
- âŠ