73 research outputs found
It is Domestic, it Must Be Healthy: How Health Consciousness and Consumer Ethnocentrism Shape Healthiness Perception and Purchase Intentions of Domestic Food
Consumer ethnocentrism (CET), healthiness perception and health consciousness have been extensively researched in regard to consumer food choices. Literature on domestic food choices provides evidence that CET positively affects consumer preferences toward domestic food. However, the effect of health consciousness on domestic food choices has not yet received a ention. Our online study (N=227, convenience sample from Lithuanian population) closes this gap by showing that health consciousness is an important individual trait in domestic food choices beyond consumer ethnocentrism and represents the first study to analyze CET in light of food healthiness perception. All constructs were measured using established self-report scales. Empirical results obtained through structural equation modelling show that (1) health consciousness increases healthiness perception and willingness to buy domestic food. Moreover, (2) health consciousness is an important individual trait in domestic food choices beyond CET; (3) healthiness perception of domestic food has an impact on consumer purchase decisions; (4) CET has a positive impact on domestic food healthiness perception. The study provides managerial implications for domestic and foreign producers
The probiotic Escherichia coli strain Nissle 1917 (EcN) stops acute diarrhoea in infants and toddlers
In most cases, acute diarrhoea will become self-limiting during the first few days after onset. For young children, however, health risks may develop when the disease lasts longer than 3 days. The purpose of the present trial was to determine whether the stool frequency of infants and toddlers suffering from acute diarrhoea could be normalised more quickly by administering the probiotic Escherichia coli Nissle 1917 (EcN) solution than by administering a placebo. The safety of EcN were also assessed. A total of 113 children (aged 2–47 months) with acute diarrhoea (> three watery or loose stools in 24 h) were randomised to either a group receiving the probiotic EcN suspension (n = 55) or a group receiving the placebo suspension (n = 58) in a confirmative, double-blind clinical trial. Depending on the age of patients, 1–3 ml per day of verum suspension (10(8) viable EcN cells per millilitre) or placebo were administered orally. The causes of the diarrhoea were viral rather than bacterial, but they were mainly unspecific infections. The median onset of treatment response (reduction of daily stool frequency to ≤ three watery or loose stools over at least 2 consecutive days) occurred more rapidly in the children receiving the EcN solution (2.5 days) than in those receiving the placebo (4.8 days), a significant difference (2.3 days; p = 0.0007). The number of patients showing a response was clearly higher (p < 0.0001) in the EcN group (52/55; 94.5%) than in the placebo group (39/58; 67.2%). EcN was found to be safe and well-tolerated, and it showed a significant superiority compared to the placebo in the treatment of acute diarrhoea in infants and toddlers. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:http://dx.doi.org/10.1007/s00431-007-0419-x) contains supplementary material, which is available to authorized users
Quark Gluon Plasma Diagnostics in a Successive Equilibrium Scenario
The relativistic Fokker Planck equation has been used to study the evolution
of the quark distribution in the quark gluon phase expected to be formed in
ultra-relativistic heavy ion collisions. The effect of thermal masses for
quarks and gluons is incorporated to take account of the in-medium properties.
We find that the kinetic equilibrium is achieved before the system reaches the
critical temperature of quark hadron phase transition. We find that chemical
equilibrium is not achieved during this time. We have evaluated the
electromagnetic probes of quark gluon plasma from the non-equilibrated quark
gluon phase and compared them with those in completely equilibrated scenario.
The hard QCD production rates for the electromagnetic ejectiles as well as the
heavy quark production rates are also calculated.Comment: Submitted to Nucl. Phys.
Photon production from a thermalized quark gluon plasma: quantum kinetics and nonperturbative aspects
We study the production of photons from a quark gluon plasma in local thermal
equilibrium by introducing a non-perturbative formulation of the real time
evolution of the density matrix. The main ingredient is the real time effective
action for the electromagnetic field to and to all
orders in . The real time evolution is completely determined by the
solution of a \emph{classical stochastic} non-local Langevin equation which
provides a Dyson-like resummation of the perturbative expansion. The Langevin
equation is solved in closed form by Laplace transform in terms of the thermal
photon polarization. A quantum kinetic description emerges directly from this
formulation. We find that photons with
\emph{thermalize} as plasmon quasiparticles in the plasma on time scales which is of the order of the lifetime of the QGP expected
at RHIC and LHC. We then obtain the direct photon yield to lowest order in
and to leading logarithmic order in in a
\emph{uniform} expansion valid at all time. The yield during a QGP lifetime is systematically larger than that obtained with the
equilibrium formulation and the spectrum features a distinct flattening for . We discuss the window of reliability of our results, the
theoretical uncertainties in \emph{any} treatment of photon emission from a QGP
in LTE and the shortcomings of the customary S-matrix approach.Comment: 31 pages. To appear in Nucl. Phys. A. New section (VII) with response
to and criticism of hep-ph/031222
Shear viscosity in theory from an extended ladder resummation
We study shear viscosity in weakly coupled hot theory using the CTP
formalism . We show that the viscosity can be obtained as the integral of a
three-point function. Non-perturbative corrections to the bare one-loop result
can be obtained by solving a decoupled Schwinger-Dyson type integral equation
for this vertex. This integral equation represents the resummation of an
infinite series of ladder diagrams which contribute to the leading order
result. It can be shown that this integral equation has exactly the same form
as the Boltzmann equation. We show that the integral equation for the viscosity
can be reexpressed by writing the vertex as a combination of polarization
tensors. An expression for this polarization tensor can be obtained by solving
another Schwinger-Dyson type integral equation. This procedure results in an
expression for the viscosity that represents a non-perturbative resummation of
contributions to the viscosity which includes certain non-ladder graphs, as
well as the usual ladders. We discuss the motivation for this resummation. We
show that these resummations can also be obtained by writing the viscosity as
an integral equation involving a single four-point function. Finally, we show
that when the viscosity is expressed in terms of a four-point function, it is
possible to further extend the set of graphs included in the resummation by
treating vertex and propagator corrections self-consistently. We discuss the
significance of such a self-consistent resummation and show that the integral
equation contains cancellations between vertex and propagator corrections.Comment: Revtex 40 pages with 29 figures, version to appear in Phys. Rev.
Heavy ion collisions with non-equilibrium Dirac-Brueckner mean fields
The influence of realistic interactions on the reaction dynamics in
intermediate energy heavy ion collisions is investigated. The mean field in
relativistic transport calculations is derived from microscopic Dirac-Brueckner
(DB) self-energies, taking non-equilibrium effects, in particular the
anisotropy of the local phase space configurations, into account. Thus this
approach goes beyond the local density approximation. A detailed analysis of
various in-plane and out-of-plane flow observables is presented for Au on Au
reactions at incident energies ranging from 250 to 800 A.MeV and the results
are compared to recent measurements of the FOPI collaboration. An overall good
agreement with in-plane flow data and a reasonable description of the
out-of-plane emission is achieved. For these results the intrinsic momentum
dependence of the non-equilibrium mean fields is important. On the other hand,
the local density approximation with the same underlying DB forces as well as a
standard non-linear version of the model are less successful in
describing the present data. This gives evidence of the applicability of self
energies derived from the DB approach to nuclear matter also far from
saturation and equilibrium.Comment: 63 pages Latex, using Elsevier style, 20 ps-figures, to appear in
Nucl. Phys.
Dyson-Schwinger Equations: Density, Temperature and Continuum Strong QCD
Continuum strong QCD is the application of models and continuum quantum field
theory to the study of phenomena in hadronic physics, which includes; e.g., the
spectrum of QCD bound states and their interactions; and the transition to, and
properties of, a quark gluon plasma. We provide a contemporary perspective,
couched primarily in terms of the Dyson-Schwinger equations but also making
comparisons with other approaches and models. Our discourse provides a
practitioners' guide to features of the Dyson-Schwinger equations [such as
confinement and dynamical chiral symmetry breaking] and canvasses
phenomenological applications to light meson and baryon properties in cold,
sparse QCD. These provide the foundation for an extension to hot, dense QCD,
which is probed via the introduction of the intensive thermodynamic variables:
chemical potential and temperature. We describe order parameters whose
evolution signals deconfinement and chiral symmetry restoration, and chronicle
their use in demarcating the quark gluon plasma phase boundary and
characterising the plasma's properties. Hadron traits change in an equilibrated
plasma. We exemplify this and discuss putative signals of the effects. Finally,
since plasma formation is not an equilibrium process, we discuss recent
developments in kinetic theory and its application to describing the evolution
from a relativistic heavy ion collision to an equilibrated quark gluon plasma.Comment: 103 Pages, LaTeX, epsfig. To appear in Progress in Particle and
Nuclear Physics, Vol. 4
pQCD-based Approach to Parton Production and Equilibration in High-Energy Nuclear Collisions
A pQCD-based model for parton production and equilibration in
ultrarelativistic heavy-ion collisions is reviewed. The model combines pQCD
processes including initial and final state radiations together with string
phenomenology for nonperturbative soft processes. Nuclear effects on the
initial parton production, such as multiple parton scattering and nuclear
shadowing of parton distribution functions are considered. Comparisons with
existing data are made and further tests of the model to constrain model
parameters are proposed. With the obtained space-time history of the parton
production, evolution of the minijet gas toward a fully equilibrated parton
plasma is studied. Direct probes of the early parton dynamics, such as
pre-equilibrium photon and dilepton production, open charm production,
suppressionand jet quenching are also reviewed.Comment: With minor modifications to appear in Physics Report
- …