1,249 research outputs found
Polar observations of transverse magnetic pulsations initiated at substorm onset in the high-latitude plasma sheet
New results for hadronic collisions in the framework of the Parton-Based Gribov-Regge Theory
We recently proposed a new approach to high energy nuclear scattering, which
treats hadronic collisions in a sophisticated way. Demanding theoretical
consistency as a minimal requirement for a realistic model, we provide a
solution for the energy conservation, screening problems and identical
elementary interactions, the so-called "Parton-Based Gribov-Regge Theory"
including enhanced diagrams. We can now present some of our results for SPS and
RHIC energies.Comment: 4 pages, 3 figures, To appear in the proceedings of Quark Matter 2002
(QM 2002), Nantes, France, 18-24 Jul 200
Effective String Theory of Vortices and Regge Trajectories
Starting from a field theory containing classical vortex solutions, we obtain
an effective string theory of these vortices as a path integral over the two
transverse degrees of freedom of the string. We carry out a semiclassical
expansion of this effective theory, and use it to obtain corrections to Regge
trajectories due to string fluctuations.Comment: 27 pages, revtex, 3 figures, corrected an error with the cutoff in
appendix E (was previously D), added more discussion of Fig. 3, moved some
material in section 9 to a new appendi
Relativistic Quark Spin Coupling Effects in the Correlations Between Nucleon Electroweak Properties
We investigate the effect of different relativistic spin couplings of
constituent quarks on nucleon electroweak properties. Within each quark spin
coupling scheme the correlations between static electroweak observables are
found to be independent of the particular shape of the momentum part of the
nucleon light-front wave function. The neutron charge form factor is very
sensitive to different choices of spin coupling schemes once the magnetic
moment is fitted to the experimental value. However, it is found rather
insensitive to the details of the momentum part of the three-quark wave
function model.Comment: 23 pages, 13 figures, requires axodraw.sty 1 figure corrected, 1
refs. added, some changes in tex
Weight suppression and weight elevation are associated with eating disorder symptomatology in women age 50 and older: Results of the gender and body image study
Objective: Weight suppression (WS), the difference between highest past non-pregnancy weight and current weight, predicts negative outcomes in eating disorders, but the impact of WS and related weight constructs are understudied in nonclinical, midlife populations. We examined WS (current weight < highest weight) and weight elevation (WE), the opposite of WS (current weight > lowest weight) and their associations with eating psychopathology in women aged 50+. Method: Participants were a community-based sample (N = 1,776, M age = 59) who completed demographic and eating psychopathology questions via online survey. WS, WE, and WS Ă WE were tested as predictors of outcome variables; BMI and medical conditions that affect weight were controlled for. Results: Individuals that were higher on WS and WE were most likely to engage in current weight loss attempts, dieting in the past 5 years, and extreme lifetime restriction. Individuals with higher WS were more likely to experience binge eating, greater frequency of weight checking, overvaluation of shape and weight, and lifetime fasting. Individuals with higher WE were more likely to report negative life impacts of eating and dieting. Higher WS and WE each predicted higher levels of skipping meals over the lifetime. Discussion: This novel study investigated WS in midlife women and introduced a new conceptualization of weight change (WE) that may be more relevant for aging populations given that women tend to gain weight with age. The findings implicate the utility of investigating both WS and WE as factors associated with eating psychopathology in midlife women
An integral method for solving nonlinear eigenvalue problems
We propose a numerical method for computing all eigenvalues (and the
corresponding eigenvectors) of a nonlinear holomorphic eigenvalue problem that
lie within a given contour in the complex plane. The method uses complex
integrals of the resolvent operator, applied to at least column vectors,
where is the number of eigenvalues inside the contour. The theorem of
Keldysh is employed to show that the original nonlinear eigenvalue problem
reduces to a linear eigenvalue problem of dimension .
No initial approximations of eigenvalues and eigenvectors are needed. The
method is particularly suitable for moderately large eigenvalue problems where
is much smaller than the matrix dimension. We also give an extension of the
method to the case where is larger than the matrix dimension. The
quadrature errors caused by the trapezoid sum are discussed for the case of
analytic closed contours. Using well known techniques it is shown that the
error decays exponentially with an exponent given by the product of the number
of quadrature points and the minimal distance of the eigenvalues to the
contour
Strong Decays of Strange Quarkonia
In this paper we evaluate strong decay amplitudes and partial widths of
strange mesons (strangeonia and kaonia) in the 3P0 decay model. We give
numerical results for all energetically allowed open-flavor two-body decay
modes of all nsbar and ssbar strange mesons in the 1S, 2S, 3S, 1P, 2P, 1D and
1F multiplets, comprising strong decays of a total of 43 resonances into 525
two-body modes, with 891 numerically evaluated amplitudes. This set of
resonances includes all strange qqbar states with allowed strong decays
expected in the quark model up to ca. 2.2 GeV. We use standard nonrelativistic
quark model SHO wavefunctions to evaluate these amplitudes, and quote numerical
results for all amplitudes present in each decay mode. We also discuss the
status of the associated experimental candidates, and note which states and
decay modes would be especially interesting for future experimental study at
hadronic, e+e- and photoproduction facilities. These results should also be
useful in distinguishing conventional quark model mesons from exotica such as
glueballs and hybrids through their strong decays.Comment: 69 pages, 5 figures, 39 table
Muon production in extensive air showers and its relation to hadronic interactions
In this work, the relation between muon production in extensive air showers
and features of hadronic multiparticle production at low energies is studied.
Using CORSIKA, we determine typical energies and phase space regions of
secondary particles which are important for muon production in extensive air
showers and confront the results with existing fixed target measurements.
Furthermore possibilities to measure relevant quantities of hadron production
in existing and planned accelerator experiments are discussed.Comment: To appear in the proceedings of international conference on
interconnection between high energy physics and astroparticle physics "From
Colliders to Cosmic Rays" (C2CR 2005), Prague, Czech Republic, 7-13 September
200
Confining QCD Strings, Casimir Scaling, and a Euclidean Approach to High-Energy Scattering
We compute the chromo-field distributions of static color-dipoles in the
fundamental and adjoint representation of SU(Nc) in the loop-loop correlation
model and find Casimir scaling in agreement with recent lattice results. Our
model combines perturbative gluon exchange with the non-perturbative stochastic
vacuum model which leads to confinement of the color-charges in the dipole via
a string of color-fields. We compute the energy stored in the confining string
and use low-energy theorems to show consistency with the static quark-antiquark
potential. We generalize Meggiolaro's analytic continuation from parton-parton
to gauge-invariant dipole-dipole scattering and obtain a Euclidean approach to
high-energy scattering that allows us in principle to calculate S-matrix
elements directly in lattice simulations of QCD. We apply this approach and
compute the S-matrix element for high-energy dipole-dipole scattering with the
presented Euclidean loop-loop correlation model. The result confirms the
analytic continuation of the gluon field strength correlator used in all
earlier applications of the stochastic vacuum model to high-energy scattering.Comment: 65 pages, 13 figures, extended and revised version to be published in
Phys. Rev. D (results unchanged, 2 new figures, 1 new table, additional
discussions in Sec.2.3 and Sec.5, new appendix on the non-Abelian Stokes
theorem, old Appendix A -> Sec.3, several references added
Sweet taste preference in binge-eating disorder: A preliminary investigation
Research suggests that individuals with high liking for sweets are at increased risk for binge eating, which has been minimally investigated in individuals with binge-eating disorder (BED). Forty-one adults (85% female, 83% white) with binge eating concerns completed a sweet taste test and measures of eating disorder behaviors and food cravings. A subset of participants with BED completed an oral glucose tolerance test (OGTT; N = 21) and a 24-hour dietary recall (N = 26). Regression models were used to compare highest sweet preferers (HSP [N = 18]) to other sweet preferers (OSP [N = 23]) and were used to assess associations between sweet taste preference and outcome variables. Effect sizes (ηp2) for differences between HSP and OSP ranged from small (†0.01) to large (℠0.24); group differences were statistically nonsignificant except for 24-hour caloric intake (ηp2 = 0.16, p = 0.04), protein intake (ηp2 = 0.16, p = 0.04), and insulin sensitivity index (ηp2 = 0.24, p = 0.04), which were higher in HSP, and postprandial insulin, which was smaller in HSP (ηp2 = 0.27, p = 0.03). Continuous analyses replicated postprandial insulin response. Compared with OSP, HSP reported numerically higher binge-eating frequency (ηp2 = 0.04), over-eating frequency (ηp2 = 0.06), and carbohydrate intake (ηp2 = 0.14), and they exhibited numerically smaller postprandial glucose AUC (ηp2 = 0.16). Sweet taste preference may have implications for glucose regulation, binge-eating frequency, and nutrient intake in BED
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