1,207 research outputs found
Possible large phase in psi(2S) -> 1-0- Decays
The strong and the electromagnetic amplitudes are analyzed on the basis of
the measurements of J/psi, psi(2S) -> 1-0- in e+e- experiments. The currently
available experimental information is revised with inclusion of the
contribution from e+e- -> gamma * -> 1-0- . The study shows that a large phase
around minus 90 degree between the strong and the electromagnetic amplitudes
could not be ruled out by the experimental data for psi(2S).Comment: 4 page
Electromagnetic form factors in the J/\psi mass region: The case in favor of additional resonances
Using the results of our recent analysis of e^+e^- annihilation, we plot the
curves for the diagonal and transition form factors of light hadrons in the
time-like region up to the production threshold of an open charm quantum
number. The comparison with existing data on the decays of J/\psi into such
hadrons shows that some new resonance structures may be present in the mass
range between 2 GeVand the J/\psi mass. Searching them may help in a better
understanding of the mass spectrum in both the simple and a more sophisticated
quark models, and in revealing the details of the three-gluon mechanism of the
OZI rule breaking in K\bar K channel.Comment: Formulas are added, typo is corrected, the text is rearranged.
Replaced to match the version accepted in Phys Rev
Tri-meson-mixing of -- and -- in the light-cone quark model
The radiative transition form factors of the pseudoscalar mesons {,
, } and the vector mesons {, , } are restudied
with -- and -- in tri-meson-mixing
pattern, which is described by tri-mixing matrices in the light-cone
constituent quark model. The experimental transition decay widths are better
reproduced with tri-meson-mixing than previous results in a two-mixing-angle
scenario of only two-meson - mixing and - mixing.Comment: 8 pages, 6 figures, final version to appear in EPJ
A possible hadronic excess in psi(2S) decay and rho-pi puzzle
We examine the so-called rho-pi puzzle of the psi(2S) decay by incorporating
two inputs: One is the relative phase between the one-photon and the gluon
decay amplitude, and the other is a possible anomaly in the inclusive
nonelectromagnetic decay rate of psi(2S). We propose the possibility that in
the psi(2S) decay a hadronic decay process of long distance origin is important
in addition to the short-distance decay process. The amplitude of this
additional process should nearly cancel the three-gluon amplitude in the
exclusive psi(2S)---> 1-0- and turn the sum dominantly real in contrast to the
J/psi decay. We present general consequences of this mechanism and then briefly
look into two models which possibly explain the course of this additional
amplitude.Comment: 14 pages, 2 Tables, and 3 eps figures. Replaces the original version
with a minor change in the title and inclusion of more references. The
version to appear in Phys. Rev.
Chronic non-specific low back pain - sub-groups or a single mechanism?
Copyright 2008 Wand and O'Connell; licensee BioMed Central Ltd.
This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0),
which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.Background: Low back pain is a substantial health problem and has subsequently attracted a
considerable amount of research. Clinical trials evaluating the efficacy of a variety of interventions
for chronic non-specific low back pain indicate limited effectiveness for most commonly applied
interventions and approaches.
Discussion: Many clinicians challenge the results of clinical trials as they feel that this lack of
effectiveness is at odds with their clinical experience of managing patients with back pain. A
common explanation for this discrepancy is the perceived heterogeneity of patients with chronic
non-specific low back pain. It is felt that the effects of treatment may be diluted by the application
of a single intervention to a complex, heterogeneous group with diverse treatment needs. This
argument presupposes that current treatment is effective when applied to the correct patient.
An alternative perspective is that the clinical trials are correct and current treatments have limited
efficacy. Preoccupation with sub-grouping may stifle engagement with this view and it is important
that the sub-grouping paradigm is closely examined. This paper argues that there are numerous
problems with the sub-grouping approach and that it may not be an important reason for the
disappointing results of clinical trials. We propose instead that current treatment may be ineffective
because it has been misdirected. Recent evidence that demonstrates changes within the brain in
chronic low back pain sufferers raises the possibility that persistent back pain may be a problem of
cortical reorganisation and degeneration. This perspective offers interesting insights into the
chronic low back pain experience and suggests alternative models of intervention.
Summary: The disappointing results of clinical research are commonly explained by the failure of
researchers to adequately attend to sub-grouping of the chronic non-specific low back pain
population. Alternatively, current approaches may be ineffective and clinicians and researchers may
need to radically rethink the nature of the problem and how it should best be managed
Pseudomonas aeruginosa Adaptation to Lungs of Cystic Fibrosis Patients Leads to Lowered Resistance to Phage and Protist Enemies
Pathogenic life styles can lead to highly specialized interactions with host species, potentially resulting in fitness trade-offs in other ecological contexts. Here we studied how adaptation of the environmentally transmitted bacterial pathogen, Pseudomonas aeruginosa, to cystic fibrosis (CF) patients affects its survival in the presence of natural phage (14/1, ΦKZ, PNM and PT7) and protist (Tetrahymena thermophila and Acanthamoebae polyphaga) enemies. We found that most of the bacteria isolated from relatively recently intermittently colonised patients (1-25 months), were innately phage-resistant and highly toxic for protists. In contrast, bacteria isolated from long time chronically infected patients (2-23 years), were less efficient in both resisting phages and killing protists. Moreover, chronic isolates showed reduced killing of wax moth larvae (Galleria mellonella) probably due to weaker in vitro growth and protease expression. These results suggest that P. aeruginosa long-term adaptation to CF-lungs could trade off with its survival in aquatic environmental reservoirs in the presence of microbial enemies, while lowered virulence could reduce pathogen opportunities to infect insect vectors; factors that are both likely to result in poorer environmental transmission. From an applied perspective, phage therapy could be useful against chronic P. aeruginosa lung infections that are often characterized by multidrug resistance: chronic isolates were least resistant to phages and their poor growth will likely slow down the emergence of beneficial resistance mutations
Microgravimetric measurements at the 1994 international comparison of absolute gravimeters
International audienc
Activation of store-operated calcium entry in airway smooth muscle cells: insight from a mathematical model
Intracellular dynamics of airway smooth muscle cells (ASMC) mediate ASMC contraction and proliferation, and thus play a key role in airway hyper-responsiveness (AHR) and remodelling in asthma. We evaluate the importance of store-operated entry (SOCE) in these dynamics by constructing a mathematical model of ASMC signaling based on experimental data from lung slices. The model confirms that SOCE is elicited upon sufficient depletion of the sarcoplasmic reticulum (SR), while receptor-operated entry (ROCE) is inhibited in such conditions. It also shows that SOCE can sustain agonist-induced oscillations in the absence of other influx. SOCE up-regulation may thus contribute to AHR by increasing the oscillation frequency that in turn regulates ASMC contraction. The model also provides an explanation for the failure of the SERCA pump blocker CPA to clamp the cytosolic of ASMC in lung slices, by showing that CPA is unable to maintain the SR empty of . This prediction is confirmed by experimental data from mouse lung slices, and strongly suggests that CPA only partially inhibits SERCA in ASMC
Search for supersymmetry with a dominant R-parity violating LQDbar couplings in e+e- collisions at centre-of-mass energies of 130GeV to 172 GeV
A search for pair-production of supersymmetric particles under the assumption
that R-parity is violated via a dominant LQDbar coupling has been performed
using the data collected by ALEPH at centre-of-mass energies of 130-172 GeV.
The observed candidate events in the data are in agreement with the Standard
Model expectation. This result is translated into lower limits on the masses of
charginos, neutralinos, sleptons, sneutrinos and squarks. For instance, for
m_0=500 GeV/c^2 and tan(beta)=sqrt(2) charginos with masses smaller than 81
GeV/c^2 and neutralinos with masses smaller than 29 GeV/c^2 are excluded at the
95% confidence level for any generation structure of the LQDbar coupling.Comment: 32 pages, 30 figure
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