425 research outputs found
Two-pion bound state in sigma channel at finite temperature
We study how we can understand the change of the spectral function and the
pole location of the correlation function for sigma at finite temperature,
which were previously obtained in the linear sigma model with a resummation
technique called optimized perturbation theory. There are two relevant poles in
the sigma channel. One pole is the original sigma pole which shows up as a
broad peak at zero temperature and becomes lighter as the temperature
increases. The behavior is understood from the decreasing of the sigma
condensate, which is consistent with the Brown-Rho scaling. The other pole
changes from a virtual state to a bound state of pion-pion as the temperature
increases which causes the enhancement at the pion-pion threshold. The behavior
is understood as the emergence of the pion-pion bound state due to the
enhancement of the pion-pion attraction by the induced emission in medium. The
latter pole, not the former, eventually degenerates with pion above the
critical temperature of the chiral transition. This means that the observable
"sigma" changes from the former to the latter pole, which can be interpreted as
the level crossing of "sigma" and pion-pion at finite temperature.Comment: 4 pages, 4 figure
Association between perceived chewing ability and oral health-related quality of life in partially dentate patients
<p>Abstract</p> <p>Background</p> <p>One of the most immediate and important functional consequences of many oral disorders is a reduction in chewing ability. The ability to chew is not only an important dimension of oral health, but is increasingly recognized as being associated with general health status. Whether perceived chewing ability and oral health-related quality of life (OHRQoL) are correlated to a similar degree in patient populations has been less investigated. The aim of this study was to examine whether perceived chewing ability was related to OHRQoL in partially dentate patients.</p> <p>Methods</p> <p>Consecutive partially dentate patients (N = 489) without signs or symptoms of acute oral disease at Tokyo Medical and Dental University's Prosthodontic Clinic participated in the study (mean age 63.0 ± 11.5, 71.2% female). A 20-item chewing function questionnaire (score range 0 to 20) was used to assess perceived chewing ability, with higher scores indicating better chewing ability. The 14-item Oral Health Impact Profile-Japanese version (OHIP-J14, score range 0 to 56) was used to measure OHRQoL, with higher scores indicating poorer OHRQoL. A Pearson correlation coefficient was calculated to assess the correlation between the two questionnaire summary scores. A linear regression analysis was used to describe how perceived chewing ability scores were related to OHRQoL scores.</p> <p>Results</p> <p>The mean chewing function score was 12.1 ± 4.8 units. The mean OHIP-J14 summary score was 13.0 ± 9.1 units. Perceived chewing ability and OHRQoL were significantly correlated (Pearson correlation coefficient: -0.46, 95% confidence interval [CI]: -0.52 to -0.38), indicating that higher chewing ability was correlated with lower OHIP-J14 summary scores (p < 0.001), which indicate better OHRQoL. A 1.0-unit increase in chewing function scores was related to a decrease of 0.87 OHIP-J14 units (95% CI: -1.0 to -0.72, p < 0.001). The correlation between perceived chewing ability and OHRQoL was not substantially influenced by age and number of teeth, but by gender, years of schooling, treatment demand and denture status.</p> <p>Conclusion</p> <p>Patients' perception of their chewing ability was substantially related to their OHRQoL.</p
Spectral Function of Fermion Coupled with Massive Vector Boson at Finite Temperature in Gauge Invariant Formalism
We investigate spectral properties of a fermion coupled with a massive gauge
boson with a mass m at finite temperature (T) in the perturbation theory. The
massive gauge boson is introduced as a U(1) gauge boson in the Stueckelberg
formalism with a gauge parameter \alpha. We find that the fermion spectral
function has a three-peak structure for T \sim m irrespective of the choice of
the gauge parameter, while it tends to have one faint peak at the origin and
two peaks corresponding to the normal fermion and anti-plasmino excitations
familiar in QED in the hard thermal loop approximation for T \gg m. We show
that our formalism successfully describe the fermion spectral function in the
whole T region with the correct high-T limit except for the faint peak at the
origin, although some care is needed for choice of the gauge parameter for T
\gg m. We clarify that for T \sim m, the fermion pole is almost independent of
the gauge parameter in the one-loop order, while for T \gg m, the one-loop
analysis is valid only for \alpha \ll 1/g where g is the fermion-boson coupling
constant, implying that the one-loop analysis can not be valid for large gauge
parameters as in the unitary gauge.Comment: 28pages, 11figures. v2: typos fixe
Activation of Soil and Chemical Reagents Exposed to the Neutrons Released by the JCO Criticality Accident in Tokai-mura
Significance of Exercise-Related Ventricular Arrhythmias in Patients With Brugada Syndrome
Background
Sinus tachycardia during exercise attenuates ST‐segment elevation in patients with Brugada syndrome, whereas ST‐segment augmentation after an exercise test is a high‐risk sign. Some patients have premature ventricular contractions (PVCs) related to exercise, but the significance of exercise‐related PVCs in patients with Brugada syndrome is still unknown. The objective of this study was to determine the significance of exercise‐related PVCs for predicting occurrence of ventricular fibrillation (VF) in patients with Brugada syndrome.
Methods and Results
The subjects were 307 patients with Brugada syndrome who performed a treadmill exercise test. We evaluated the occurrence of PVCs at rest, during exercise and at the peak of exercise, and during recovery after exercise (0–5 minutes). We followed the patients for 92±68 months and evaluated the occurrence of VF. PVCs occurred in 82 patients (27%) at the time of treadmill exercise test: PVCs appeared at rest in 14 patients (4%), during exercise in 60 patients (20%), immediately after exercise (0–1.5 minutes) in 28 patients (9%), early after exercise (1.5–3 minutes) in 18 patients (6%), and late after exercise (3–5 minutes) in 12 patients (4%). Thirty patients experienced VF during follow‐up. Multivariable analysis including symptoms, spontaneous type 1 ECG, and PVCs in the early recovery phase showed that these factors were independently associated with VF events during follow‐up.
Conclusions
PVCs early after an exercise test are associated with future occurrence of VF events. Rebound of vagal nerve activity at the early recovery phase would promote ST‐segment augmentation and PVCs in high‐risk patients with Brugada syndrome
Large-Area Resonance-Tuned Metasurfaces for On-Demand Enhanced Spectroscopy
We show an effective procedure for lateral structure tuning in nanoimprint lithography (NIL) that has been developed as a vertical top-down method fabricating large-area nanopatterns. The procedure was applied to optical resonance tuning in stacked complementary (SC) metasurfaces based on silicon-on-insulator (SOI) substrates and was found to realize structure tuning at nm precision using only one mold in the NIL process. The structure tuning enabled us to obtain fine tuning of the optical resonances, offering cost-effective, high-throughput, and high-precision nanofabrication. We also demonstrate that the tuned optical resonances selectively and significantly enhance fluorescence (FL) of dye molecules in a near-infrared range. FL intensity on a SC metasurface was found to be more than 450-fold larger than the FL intensity on flat Au film on base SOI substrate
Hard thermal loops, to quadratic order, in the background of a spatial 't Hooft loop
We compute the simplest hard thermal loops for a spatial 't Hooft loop in the
deconfined phase of a SU(N) gauge theory. We expand to quadratic order about a
constant background field A_0 = Q/g, where Q is a diagonal, color matrix and g
is the gauge coupling constant. We analyze the problem in sufficient generality
that the techniques developed can be applied to compute transport properties in
a "semi"-Quark Gluon Plasma. Notably, computations are done using the double
line notation at finite N. The quark self-energy is a Q-dependent thermal mass
squared, of order g^2T^2, where T is the temperature, times the same hard
thermal loop as at Q=0. The gluon self-energy involves two pieces: a
Q-dependent Debye mass squared, of order g^2T^2, times the same hard thermal
loop as for Q=0, plus a new hard thermal loop, of order g^2T^3, due to the
color electric field generated by a spatial 't Hooft loop.Comment: 52 pages, 10 figures; Eqs. (118), (137), and (158) have been
corrected. We thank H. Nishimura and V. V. Skokov for pointing this ou
The Dichotomous Nucleon: Some Radical Conjectures for the Large Nc Limit
We discuss some problems with the large Nc approximation for nucleons which
arise if the axial coupling of the nucleon to pions is large, g_A \sim Nc.
While g_A \sim Nc in non-relativistic quark and Skyrme models, it has been
suggested that Skyrmions may collapse to a small size, r \sim 1/f_pi \sim
Lambda_QCD^{-1}/sqrt(Nc). (This is also the typical scale over which the string
vertex moves in a string vertex model of the baryon.) We concentrate on the
case of two flavors, where we suggest that to construct a nucleon with a small
axial coupling, that most quarks are bound into colored diquark pairs, which
have zero spin and isospin. For odd Nc, this leaves one unpaired quark, which
carries the spin and isospin of the nucleon. If the unpaired quark is in a
spatial wavefunction orthogonal to the wavefunctions of the scalar diquarks,
then up to logarithms of Nc, the unpaired quark only costs an energy \sim
Lambda_QCD. This naturally gives g_A \sim 1 and has other attractive features.
In nature, the wavefunctions of the paired and unpaired quarks might only be
approximately orthogonal; then g_A depends weakly upon Nc. This dichotomy in
wave functions could arise if the unpaired quark orbits at a size which is
parametrically large in comparison to that of the diquarks. We discuss possible
tests of these ideas from numerical simulations on the lattice, for two flavors
and three and five colors; the extension of our ideas to more than three or
more flavors is not obvious, though.Comment: Published version in Nucl. Phys.
Prospective clinical study of R-CMD therapy for indolent B cell lymphoma and mantle cell lymphoma from the Hokuriku Hematology Oncology Study Group
Cerebrospinal fluid levels of opioid peptides in fibromyalgia and chronic low back pain
BACKGROUND: The mechanism(s) of nociceptive dysfunction and potential roles of opioid neurotransmitters are unresolved in the chronic pain syndromes of fibromyalgia and chronic low back pain. METHODS: History and physical examinations, tender point examinations, and questionnaires were used to identify 14 fibromyalgia, 10 chronic low back pain and 6 normal control subjects. Lumbar punctures were performed. Met-enkephalin-Arg(6)-Phe(7 )(MEAP) and nociceptin immunoreactive materials were measured in the cerebrospinal fluid by radioimmunoassays. RESULTS: Fibromyalgia (117.6 pg/ml; 85.9 to 149.4; mean, 95% C.I.; p = 0.009) and low back pain (92.3 pg/ml; 56.9 to 127.7; p = 0.049) groups had significantly higher MEAP than the normal control group (35.7 pg/ml; 15.0 to 56.5). MEAP was inversely correlated to systemic pain thresholds. Nociceptin was not different between groups. Systemic Complaints questionnaire responses were significantly ranked as fibromyalgia > back pain > normal. SF-36 domains demonstrated severe disability for the low back pain group, intermediate results in fibromyalgia, and high function in the normal group. CONCLUSIONS: Fibromyalgia was distinguished by higher cerebrospinal fluid MEAP, systemic complaints, and manual tender points; intermediate SF-36 scores; and lower pain thresholds compared to the low back pain and normal groups. MEAP and systemic pain thresholds were inversely correlated in low back pain subjects. Central nervous system opioid dysfunction may contribute to pain in fibromyalgia
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