712 research outputs found
Sense of taste in Slow Food. About social processes that influence sense of taste
In deze scriptie wordt verslag gedaan van een verkennend onderzoek naar, enerzijds, de
identiteit van mensen die eten met aandacht, slow fooders genaamd, en anderzijds naar hun
smaakbeleving
Towards nonlinear quantum Fokker-Planck equations
It is demonstrated how the equilibrium semiclassical approach of Coffey et
al. can be improved to describe more correctly the evolution. As a result a new
semiclassical Klein-Kramers equation for the Wigner function is derived, which
remains quantum for a free quantum Brownian particle as well. It is transformed
to a semiclassical Smoluchowski equation, which leads to our semiclassical
generalization of the classical Einstein law of Brownian motion derived before.
A possibility is discussed how to extend these semiclassical equations to
nonlinear quantum Fokker-Planck equations based on the Fisher information
Is a chest radiograph indicated after chest tube removal in trauma patients? A systematic review
PURPOSE The aim of this systematic review was to assess the necessity of routine chest radiographs after chest tube removal in ventilated and nonventilated trauma patients. METHODS A systematic literature search was conducted in MEDLINE, Embase, CENTRAL, and CINAHL on May 15, 2020. Quality assessment was performed using the Methodological Index for Nonrandomized Studies criteria. Primary outcome measures were abnormalities on postremoval chest radiograph (e.g., recurrence of a pneumothorax, hemothorax, pleural effusion) and reintervention after chest tube removal. Secondary outcome measures were emergence of new clinical symptoms or vital signs after chest tube removal. RESULTS Fourteen studies were included, consisting of seven studies on nonventilated patients and seven studies on combined cohorts of ventilated and nonventilated patients, all together containing 1,855 patients. Nonventilated patients had abnormalities on postremoval chest radiograph in 10% (range across studies, 0-38%) of all chest tubes and 24% (range, 0-78%) of those underwent reintervention. In the studies that reported on clinical symptoms after chest tube removal, all patients who underwent reintervention also had symptoms of recurrent pathology. Combined cohorts of ventilated and nonventilated patients had abnormalities on postremoval chest radiograph in 20% (range, 6-49%) of all chest tubes and 45% (range, 8-63%) of those underwent reintervention. CONCLUSION In nonventilated patients, one in ten developed recurrent pathology after chest tube removal and almost a quarter of them underwent reintervention. In two studies that reported on clinical symptoms, all reinterventions were performed in patients with symptoms of recurrent pathology. In these two studies, omission of routine postremoval chest radiograph seemed safe. However, current literature remains insufficient to draw definitive conclusions on this matter, and future studies are needed. LEVEL OF EVIDENCE Systematic review study, level IV
Salerno's model of DNA reanalysed: could solitons have biological significance?
We investigate the sequence-dependent behaviour of localised excitations in a
toy, nonlinear model of DNA base-pair opening originally proposed by Salerno.
Specifically we ask whether ``breather'' solitons could play a role in the
facilitated location of promoters by RNA polymerase. In an effective potential
formalism, we find excellent correlation between potential minima and {\em
Escherichia coli} promoter recognition sites in the T7 bacteriophage genome.
Evidence for a similar relationship between phage promoters and downstream
coding regions is found and alternative reasons for links between AT richness
and transcriptionally-significant sites are discussed. Consideration of the
soliton energy of translocation provides a novel dynamical picture of sliding:
steep potential gradients correspond to deterministic motion, while ``flat''
regions, corresponding to homogeneous AT or GC content, are governed by random,
thermal motion. Finally we demonstrate an interesting equivalence between
planar, breather solitons and the helical motion of a sliding protein
``particle'' about a bent DNA axis.Comment: Latex file 20 pages, 5 figures. Manuscript of paper to appear in J.
Biol. Phys., accepted 02/09/0
Phase structures of strong coupling lattice QCD with finite baryon and isospin density
Quantum chromodynamics (QCD) at finite temperature (T), baryon chemical
potential (\muB) and isospin chemical potential (\muI) is studied in the strong
coupling limit on a lattice with staggered fermions. With the use of large
dimensional expansion and the mean field approximation, we derive an effective
action written in terms of the chiral condensate and pion condensate as a
function of T, \muB and \muI. The phase structure in the space of T and \muB is
elucidated, and simple analytical formulas for the critical line of the chiral
phase transition and the tricritical point are derived. The effects of a finite
quark mass (m) and finite \muI on the phase diagram are discussed. We also
investigate the phase structure in the space of T, \muI and m, and clarify the
correspondence between color SU(3) QCD with finite isospin density and color
SU(2) QCD with finite baryon density. Comparisons of our results with those
from recent Monte Carlo lattice simulations on finite density QCD are given.Comment: 18 pages, 6 figures, revtex4; some discussions are clarified, version
to appear in Phys. Rev.
Nonlinear Realization of Chiral Symmetry on the Lattice
We formulate lattice theories in which chiral symmetry is realized
nonlinearly on the fermion fields. In this framework the fermion mass term does
not break chiral symmetry. This property allows us to use the Wilson term to
remove the doubler fermions while maintaining exact chiral symmetry on the
lattice. Our lattice formulation enables us to address non-perturbative
questions in effective field theories of baryons interacting with pions and in
models involving constituent quarks interacting with pions and gluons. We show
that a system containing a non-zero density of static baryons interacting with
pions can be studied on the lattice without encountering complex action
problems. In our formulation one can also decide non-perturbatively if the
chiral quark model of Georgi and Manohar provides an appropriate low-energy
description of QCD. If so, one could understand why the non-relativistic quark
model works.Comment: 34 pages, 2 figures, revised version to be published in J. High
Energy Phys. (changes in the 1st paragraph, additional descriptions on the
nature of the coordinate singularities in Sec.2, references added
On the detectability of the CMSSM light Higgs boson at the Tevatron
We examine the prospects of detecting the light Higgs h^0 of the Constrained
MSSM at the Tevatron. To this end we explore the CMSSM parameter space with
\mu>0, using a Markov Chain Monte Carlo technique, and apply all relevant
collider and cosmological constraints including their uncertainties, as well as
those of the Standard Model parameters. Taking 50 GeV < m_{1/2}, m_0 < 4 TeV,
|A_0| < 7 TeV and 2 < tan(beta) < 62 as flat priors and using the formalism of
Bayesian statistics we find that the 68% posterior probability region for the
h^0 mass lies between 115.4 GeV and 120.4 GeV. Otherwise, h^0 is very similar
to the Standard Model Higgs boson. Nevertheless, we point out some enhancements
in its couplings to bottom and tau pairs, ranging from a few per cent in most
of the CMSSM parameter space, up to several per cent in the favored region of
tan(beta)\sim 50 and the pseudoscalar Higgs mass of m_A\lsim 1 TeV. We also
find that the other Higgs bosons are typically heavier, although not
necessarily much heavier. For values of the h^0 mass within the 95% probability
range as determined by our analysis, a 95% CL exclusion limit can be set with
about 2/fb of integrated luminosity per experiment, or else with 4/fb (12/fb) a
3 sigma evidence (5 sigma discovery) will be guaranteed. We also emphasize that
the alternative statistical measure of the mean quality-of-fit favors a
somewhat lower Higgs mass range; this implies even more optimistic prospects
for the CMSSM light Higgs search than the more conservative Bayesian approach.
In conclusion, for the above CMSSM parameter ranges, especially m_0, either
some evidence will be found at the Tevatron for the light Higgs boson or, at a
high confidence level, the CMSSM will be ruled out.Comment: JHEP versio
Revisiting the Higgs Mass and Dark Matter in the CMSSM
Taking into account the available accelerator and astrophysical constraints,
the mass of the lightest neutral Higgs boson h in the minimal supersymmetric
extension of the Standard Model with universal soft supersymmetry-breaking
masses (CMSSM) has been estimated to lie between 114 and ~ 130 GeV. Recent data
from ATLAS and CMS hint that m_h ~ 125 GeV, though m_h ~ 119 GeV may still be a
possibility. Here we study the consequences for the parameters of the CMSSM and
direct dark matter detection if the Higgs hint is confirmed, focusing on the
strips in the (m_1/2, m_0) planes for different tan beta and A_0 where the
relic density of the lightest neutralino chi falls within the range of the
cosmological cold dark matter density allowed by WMAP and other experiments. We
find that if m_h ~ 125 GeV focus-point strips would be disfavoured, as would
the low-tan beta stau-chi and stop -chi coannihilation strips, whereas the
stau-chi coannihilation strip at large tan beta and A_0 > 0 would be favoured,
together with its extension to a funnel where rapid annihilation via
direct-channel H/A poles dominates. On the other hand, if m_h ~ 119 GeV more
options would be open. We give parametrizations of WMAP strips with large tan
beta and fixed A_0/m_0 > 0 that include portions compatible with m_h = 125 GeV,
and present predictions for spin-independent elastic dark matter scattering
along these strips. These are generally low for models compatible with m_h =
125 GeV, whereas the XENON100 experiment already excludes some portions of
strips where m_h is smaller.Comment: 24 pages, 9 figure
Gauge and Scheme Dependence of Mixing Matrix Renormalization
We revisit the issue of mixing matrix renormalization in theories that
include Dirac or Majorana fermions. We show how a gauge-variant on-shell
renormalized mixing matrix can be related to a manifestly gauge-independent one
within a generalized scheme of renormalization. This
scheme-dependent relation is a consequence of the fact that in any scheme of
renormalization, the gauge-dependent part of the mixing-matrix counterterm is
ultra-violet safe and has a pure dispersive form. Employing the unitarity
properties of the theory, we can successfully utilize the afore-mentioned
scheme-dependent relation to preserve basic global or local symmetries of the
bare Lagrangian through the entire process of renormalization. As an immediate
application of our study, we derive the gauge-independent renormalization-group
equations of mixing matrices in a minimal extension of the Standard Model with
isosinglet neutrinos.Comment: 31 pages, LaTeX, uses axodraw.st
Long-lived K isomer and enhanced gamma vibration in the neutron-rich nucleus Dy-172: Collectivity beyond double midshell
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