2,527 research outputs found
coupling constant in light cone QCD sum rules
We employ the light cone QCD sum rules to calculate coupling
constant by studying the two point correlation function between the vacuum and
the pion state. Our result is consistent with the traditional QCD sum rules
calculations and it is in agreement with the experimental value.Comment: 8 pages, latex, 2 figure
Correlational study and randomised controlled trial for understanding and changing red meat consumption: The role of eating identities
Rationale: The present studies aimed to contribute to the literature on psychological variables involved in reducing red meat consumption (RMC). Objective: Study 1 investigated whether the theory of planned behaviour (TPB), plus healthy-eating and meat-eating identities, could explain intentions to reduce RMC. Study 2 evaluated the effectiveness of an SMS text message intervention on self-monitoring to reduce RMC. Methods: In Study 1, data were collected daily using online food diaries for one week and a TPB questionnaire. Study 2 was a randomised controlled trial assessing pre– and post–RMC and TPB constructs by online food diaries and questionnaires over a one-week period. Participants were Italian undergraduates in each study (Study 1: N = 405; Study 2: N = 244). In Study 2, participants were randomly allocated to control and message condition groups. Participants in the message condition group received a daily SMS, which reminded them to monitor RMC, while participants in the control group did not receive any message. Only students who completed all measures were considered in the analyses (Study 1: N = 342; Study 2: N = 228). Results: Study 1 showed that affective and instrumental attitudes, perceived behavioural control, and meat-eating identity explained intentions to reduce RMC, while subjective norm, past behaviour, and healthy-eating identity did not. Study 2 showed that an SMS intervention was effective in increasing intentions and reducing RMC. Mediation analyses indicated partial serial mediation through healthy-eating and meat-eating identities and intentions. Conclusion: The present studies provide support for the predictive validity of TPB in explaining intentions to reduce RMC and for the efficacy of an SMS intervention targeting self-monitoring in reducing RMC. Findings confirmed the important role of eating identities in explaining intentions to reduce RMC and in changing this behaviour
Moderating effects of pro-environmental self-identity on pro-environmental intentions and behaviour: a multi-behaviour study
Self-identity is considered as a useful additional predictor in the theory of planned behaviour (TPB). However, previous research generally assessed the impact of pro-environmental self-identity in relation to single behaviours and no studies considered its potential role in moderating the impact of other predictors on behaviour. The present research used a within-persons approach to examine effects across behaviours and a longitudinal design to assess the moderating role of self-identity in the prediction of intentions and behaviours, controlling for past behaviour. Participants (N = 240) completed Time 1 questionnaires measuring TPB constructs in relation to five different pro-environmental behaviours. Two weeks later, participants (N = 220) responded to a questionnaire assessing self-reports of these behaviours during the intervening two-week period. Across pro-environmental behaviours the findings showed that pro-environmental self-identity significantly moderated the impact of perceived behavioural control on intentions and the effect of past behaviour on both intentions and behaviours
Quark structure of hadrons and high energy collisions
There exists a large field for phenomenological models in which the knowledge
of the structure of hadrons in terms of QCD constituents obtained from deep
inelastic scatterings is related to their behaviour in soft processes. One of
the simplest and oldest models is the additive quark model, with the rules of
quark statistics following from it. Originally, the relations of quark
combinatorics for hadron yields were based on the qualitative description of a
multiparticle production process as a process of the production of
non-correlated quarks and antiquarks followed by their subsequent fusion into
hadrons [20],[21]. As a large amount of new precision measurements appear, and,
on the other hand, our understanding of QCD becomes deeper, a new level of
understanding of quark-gluon physics in the region of soft interactions forces
us to review the relations of quark combinatorics. To do so, an especially good
possibility is provided by the experimental data for hadronic Z^0 decays which
allow us to check the relations of quark combinatorics for a new type of
processes: quark jets in the decays Z^0 -> q\bar{q} -> hadrons [32].Comment: 55 pages, 23 figure
Combined flow-based imaging assessment of optimal cardiac resynchronization therapy pacing vector: A case report
Background: There are still many pendent issues about the effective evaluation of cardiac resynchronization
therapy impact on functional mitral regurgitation. In order to reduce the intrinsic difficulties of quantification of
functional mitral regurgitation itself, an automatic quantification of real-time three-dimensional full-volume color
Doppler transthoracic echocardiography was proposed as a new, rapid, and accurate method for the assessment of
functional mitral regurgitation severity. Recent studies suggested that images of left ventricle flow by echo-particle
imaging velocimetry could be a useful marker of synchrony. Echo-particle imaging velocimetry has shown that
regional anomalies of synchrony/synergy of the left ventricle are related to the alteration, reduction, or suppression
of the physiological intracavitary pressure gradients.
Case summary: We describe a case in which the two technologies are used in combination during acute
echocardiographic optimization of left pacing vector in a 63-year-old man, Caucasian, who showed worsening heart
failure symptoms a few days after an implant, and the effect of the device\u2019s optimization at 6-month follow-up.
Discussion: The degree of realignment of hemodynamic forces, with quantitative analysis of the orientation of blood
flow momentum (\u3c6), can represent improvement of fluid dynamics synchrony of the left ventricle, and explain, with a
new deterministic parameter, the effects of cardiac resynchronization therapy on functional mitral regurgitation. Realtime three-dimensional color flow Doppler quantification is feasible and accurate for measurement of mitral inflow, left
ventricular outflow stroke volumes, and functional mitral regurgitation severity.
Conclusion: This clinical case offers an innovative and accurate approach for acute echocardiographic optimization of
left pacing vector. It shows clinical utility of combined three-dimensional full-volume color Doppler transthoracic
echocardiography/echo-particle imaging velocimetry assessment to increase response to cardiac resynchronization
therapy, in terms of reduction of functional mitral regurgitation, improving fluid dynamics synchrony of the left
ventricle
Positronium Decay : Gauge Invariance and Analyticity
The construction of positronium decay amplitudes is handled through the use
of dispersion relations. In this way, emphasis is put on basic QED principles:
gauge invariance and soft-photon limits (analyticity).
A firm grounding is given to the factorization approaches, and some
ambiguities in the spin and energy structures of the positronium wavefunction
are removed. Non-factorizable amplitudes are naturally introduced. Their
dynamics is described, especially regarding the enforcement of gauge invariance
and analyticity through delicate interferences. The important question of the
completeness of the present theoretical predictions for the decay rates is then
addressed. Indeed, some of those non-factorizable contributions are unaccounted
for by NRQED analyses. However, it is shown that such new contributions are
highly suppressed, being of order alpha^3.
Finally, a particular effective form factor formalism is constructed for
parapositronium, allowing a thorough analysis of binding energy effects and
analyticity implementation.Comment: 34 pages, 13 figure
Effects of Flavor-dependent Annihilation on the Mixing Angle of the Isoscalar Octet-Singlet and Schwinger's Nonet Mass Formula
By incorporating the flavor-dependent quark-antiquark annihilation amplitude
into the mass-squared matrix describing the mixing of the isoscalar states of a
meson nonet, the new version of Schwinger's nonet mass formula which holds with
a high accuracy for the , , , and
nonets is derived and the mixing angle of isoscalar octet-singlet for these
nonets is obtained. In particular, the mixing angle of isoscalar octet-singlet
for pseudoscalar nonet is determined to take the value of , which
is in agreement with the value of deduced from a
rather exhaustive and up-to-date analysis of data. It is also pointed out that
the omission of the flavor-dependent annihilation effect might be a
factor resulting in the invalidity of Schwinger's original nonet mass formula
for pseudoscalar nonet.Comment: Latex, 7 page
B ->PV Decays in the QCD Improved Factorization Approach
Motivated by recent CELO measurements and the progress of the theory of B
decays, we investigate decay modes in
the framework of QCD improved factorization. We find that all the measured
branching ratios are well accommodated in the reasonable parameter space and
predictions for the other decay modes are well below the experimental upper
limits. We also have calculated CP asymmetries in these decay modes.Comment: 24 pages, LaTex-2e, typos correcte
The Role of the D13 (1520) Resonance in eta Electroproduction
We investigate the electroproduction of eta mesons below a center of momentum
energy of 1.6 GeV, with particular emphasis on the roles of the N*(1535) and
N*(1520) resonances. Using the effective Lagrangian approach, we show that the
transverse helicity amplitude of the N*(1535) can be extracted with good
accuracy from the new eta electroproduction data, under reasonable assumptions
for the strength of the longitudinal helicity amplitude. In addition, although
the differential cross section is found to to have a small sensitivity to the
N*(1520) resonance, it is shown that a recently completed double polarization
experiment is very sensitive to this resonance.Comment: 7 pages, Revtex, 3 figure
The "radiative Delta -> N gamma" decay in light cone QCD
The "g_{Delta N gamma}" coupling for the "Delta -> N gamma" decay is
calculated in framework of the light cone QCD sum rules and is found to be
g_{Delta N gamma} = (1.6 pm 0.2) GeV^(-1). Using this value of g_{Delta N
gamma} we estimate the branching ratio of the Delta^+ -> N gamma decay, which
is in a very good agreement with the experimental result.Comment: 9 pages, 1figures, LaTeX formatte
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