283 research outputs found
Empirical Investigation of Flexible Pricing and Payment Alternatives on Canadian Wheat Board Pooling for Wheat
Crop Production/Industries, Marketing,
Cadmium and Mercury in Macrofungi : Mechanisms of Transport and Accumulation
This is an electronic version of an article published in Angewandte Botanik: complete citation information for the final version of the
paper, as published in the print edition of Angewandte Botanik, is
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Baryons in Holographic QCD
We study the baryon in holographic QCD with multi- brane
system. In holographic QCD, the baryon appears as a topologically non-trivial
chiral soliton in a four-dimensional effective theory of mesons. We call this
topological soliton as Brane-induced Skyrmion. Some review of
holographic QCD is presented from the viewpoints of recent hadron physics and
phenomenologies. Four-dimensional effective theory with pions and mesons
is uniquely derived from the non-abelian Dirac-Born-Infeld (DBI) action of
brane with supergravity background, without small amplitude expansion of
meson fields to discuss chiral solitons. For the hedgehog configuration of pion
and -meson fields, we derive the energy functional and the Euler-Lagrange
equation of Brane-induced Skyrmion from the meson effective action induced by
holographic QCD. Performing the numerical calculation, we obtain the pion
profile and the -meson profile of the Brane-induced
Skyrmion, and estimate its total energy, energy density distribution, and
root-mean-square radius. These results are compared with the experimental
quantities of baryons and also with the profiles of standard Skyrmion without
mesons. We analyze interaction terms of pions and mesons in
Brane-induced Skyrmion, and consider the role of -meson component
appearing in baryons.Comment: 28 pages, 11 figure
Brane-induced Skyrmion on S^3: baryonic matter in holographic QCD
We study baryonic matter in holographic QCD with D4/D8/\bar{D8} multi-D brane
system in type IIA superstring theory. The baryon is described as the
"brane-induced Skyrmion", which is a topologically non-trivial chiral soliton
in the four-dimensional meson effective action induced by holographic QCD. We
employ the "truncated-resonance model" approach for the baryon analysis,
including pion and \rho meson fields below the ultraviolet cutoff scale M_KK
\sim 1GeV, to keep the holographic duality with QCD. We describe the baryonic
matter in large N_c as single brane-induced Skyrmion on the three-dimensional
closed manifold S^3 with finite radius R. The interactions between baryons are
simulated by the curvature of the closed manifold S^3, and the decrease of the
size of S^3 represents the increase of the total baryon-number density in the
medium in this modeling. We investigate the energy density, the field
configuration, the mass and the root-mean-square radius of single baryon on S^3
as the function of its radius R. We find a new picture of "pion dominance" near
the critical density in the baryonic matter, where all the (axial) vector meson
fields disappear and only the pion field survive. We also find the "swelling"
phenomena of the baryons as the precursor of the deconfinement, and propose the
mechanism of the swelling in general context of QCD. The properties of the
deconfinement and the chiral symmetry restoration in the baryonic matter are
examined by taking the proper order parameters. We also compare our
truncated-resonance model with another "instanton" description of the baryon in
holographic QCD, considering the role of cutoff scale M_KK.Comment: 25 pages, 12 figure
Gross-Neveu Models, Nonlinear Dirac Equations, Surfaces and Strings
Recent studies of the thermodynamic phase diagrams of the Gross-Neveu model
(GN2), and its chiral cousin, the NJL2 model, have shown that there are phases
with inhomogeneous crystalline condensates. These (static) condensates can be
found analytically because the relevant Hartree-Fock and gap equations can be
reduced to the nonlinear Schr\"odinger equation, whose deformations are
governed by the mKdV and AKNS integrable hierarchies, respectively. Recently,
Thies et al have shown that time-dependent Hartree-Fock solutions describing
baryon scattering in the massless GN2 model satisfy the Sinh-Gordon equation,
and can be mapped directly to classical string solutions in AdS3. Here we
propose a geometric perspective for this result, based on the generalized
Weierstrass spinor representation for the embedding of 2d surfaces into 3d
spaces, which explains why these well-known integrable systems underlie these
various Gross-Neveu gap equations, and why there should be a connection to
classical string theory solutions. This geometric viewpoint may be useful for
higher dimensional models, where the relevant integrable hierarchies include
the Davey-Stewartson and Novikov-Veselov systems.Comment: 27 pages, 1 figur
Long-term effect of mobile phone use on sleep quality: results from the cohort study of mobile phone use and health (COSMOS)
BACKGROUND: Effects of radiofrequency electromagnetic field exposure (RF-EMF) from mobile phone use on sleep quality has mainly been investigated in cross-sectional studies. The few previous prospective cohort studies found no or inconsistent associations, but had limited statistical power and short follow-up. In this large prospective cohort study, our aim was to estimate the effect of RF-EMF from mobile phone use on different sleep outcomes. MATERIALS AND METHODS: The study included Swedish (n = 21,049) and Finnish (n = 3120) participants enrolled in the Cohort Study of Mobile Phone Use and Health (COSMOS) with information about operator-recorded mobile phone use at baseline and sleep outcomes both at baseline and at the 4-year follow-up. Sleep disturbance, sleep adequacy, daytime somnolence, sleep latency, and insomnia were assessed using the Medical Outcome Study (MOS) sleep questionnaire. RESULTS: Operator-recorded mobile phone use at baseline was not associated with most of the sleep outcomes. For insomnia, an odds ratio (OR) of 1.24, 95% CI 1.03-1.51 was observed in the highest decile of mobile phone call-time (>258 min/week). With weights assigned to call-time to account for the lower RF-EMF exposure from Universal Mobile Telecommunications Service (UMTS, 3G) than from Global System for Mobile Communications (GSM, 2G) the OR was 1.09 (95% CI 0.89-1.33) in the highest call-time decile. CONCLUSION: Insomnia was slightly more common among mobile phone users in the highest call-time category, but adjustment for the considerably lower RF-EMF exposure from the UMTS than the GSM network suggests that this association is likely due to other factors associated with mobile phone use than RF-EMF. No association was observed for other sleep outcomes. In conclusion, findings from this study do not support the hypothesis that RF-EMF from mobile phone use has long-term effects on sleep quality
Commentary on the WHO classification of tumors of lymphoid tissues (2008): aggressive B-cell lymphomas
In the novel WHO classification 2008, the classification of aggressive B-cell lymphoma has been revised for several categories with the aim to define âcleanâ entities. Within large B-cell lymphoma, a few distinct clinico-pathological entities have been recognized with more clinically defined entities than pathologically defined ones. The majority of known morphological variations were not considered to merit more than classification as a variant of DLBCL, not otherwise specified. Specifically, a biological subgrouping of DLBCL on the basis of molecular (activated B-cell versus germinal center B-cell) or immunophenotypic (CD5+) features was felt to be too immature to include at this stage. The role of EBV in aggressive B-cell lymphoma has been explored in more depth with the recognition of several novel and re-defined clinico-pathological entities. Also, in these diseases, clinical definitions play a very dominant role in the WHO classification 2008
An international prospective cohort study of mobile phone users and health (COSMOS): Factors affecting validity of self-reported mobile phone use.
This study investigates validity of self-reported mobile phone use in a subset of 75 993 adults from the COSMOS cohort study. Agreement between self-reported and operator-derived mobile call frequency and duration for a 3-month period was assessed using Cohen's weighted Kappa (Îș). Sensitivity and specificity of both self-reported high (â„10 calls/day or â„4h/week) and low (â€6 calls/week or <30min/week) mobile phone use were calculated, as compared to operator data. For users of one mobile phone, agreement was fair for call frequency (Îș=0.35, 95% CI: 0.35, 0.36) and moderate for call duration (Îș=0.50, 95% CI: 0.49, 0.50). Self-reported low call frequency and duration demonstrated high sensitivity (87% and 76% respectively), but for high call frequency and duration sensitivity was lower (38% and 56% respectively), reflecting a tendency for greater underestimation than overestimation. Validity of self-reported mobile phone use was lower in women, younger age groups and those reporting symptoms during/shortly after using a mobile phone. This study highlights the ongoing value of using self-report data to measure mobile phone use. Furthermore, compared to continuous scale estimates used by previous studies, categorical response options used in COSMOS appear to improve validity considerably, most likely by preventing unrealistically high estimates from being reported
Universality of Phases in QCD and QCD-like Theories
We argue that the whole or the part of the phase diagrams of QCD and QCD-like
theories should be universal in the large-N_c limit through the orbifold
equivalence. The whole phase diagrams, including the chiral phase transitions
and the BEC-BCS crossover regions, are identical between SU(N_c) QCD at finite
isospin chemical potential and SO(2N_c) and Sp(2N_c) gauge theories at finite
baryon chemical potential. Outside the BEC-BCS crossover region in these
theories, the phase diagrams are also identical to that of SU(N_c) QCD at
finite baryon chemical potential. We give examples of the universality in some
solvable cases: (i) QCD and QCD-like theories at asymptotically high density
where the controlled weak-coupling calculations are possible, (ii) chiral
random matrix theories of different universality classes, which are solvable
large-N (large volume) matrix models of QCD. Our results strongly suggest that
the chiral phase transition and the QCD critical point at finite baryon
chemical potential can be studied using sign-free theories, such as QCD at
finite isospin chemical potential, in lattice simulations.Comment: v1: 35 pages, 6 figures; v2: 37 pages, 6 figures, minor improvements,
conclusion unchanged; v3: version published in JHE
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