580 research outputs found
Light Higgs boson scenario in the SUSY seesaw model
It is demonstrated that the light Higgs boson scenario, which the lightest
Higgs mass is less than the LEP bound, mh > 114.4 GeV, is consistent with the
SUSY seesaw model. With the assumptions of the universal right-handed neutrino
mass and the hierarchical mass spectrum of the ordinary neutrinos, the bounds
for the right-handed neutrino mass is investigated in terms of lepton flavor
violating charged lepton decays. We also discuss the effect of the modification
of renormalization group equations by the right-handed neutrinos on the b to s
gamma process and the relic abundance of dark matter in the light Higgs boson
scenario.Comment: 17 pages, 5 figure
Experimental Test of a New Equality: Measuring Heat Dissipation in an Optically Driven Colloidal System
Measurement of energy dissipation in small nonequilibrium systems is
generally a difficult task. Recently, Harada and Sasa [Phys.Rev.Lett. 95,
130602(2005)] derived an equality relating the energy dissipation rate to
experimentally accessible quantities in nonequilibrium steady states described
by the Langevin equation. Here, we show the first experimental test of this new
relation in an optically driven colloidal system. We find that this equality is
validated to a fairly good extent, thus the irreversible work of a small system
is estimated from readily obtainable quantities.Comment: 4 pages, 6 figure
Exact Analysis of ESR Shift in the Spin-1/2 Heisenberg Antiferromagnetic Chain
A systematic perturbation theory is developed for the ESR shift and is
applied to the spin-1/2 Heisenberg chain. Using the Bethe ansatz technique, we
exactly analyze the resonance shift in the first order of perturbative
expansion with respect to an anisotropic exchange interaction. Exact result for
the whole range of temperature and magnetic field, as well as asymptotic
behavior in the low-temperature limit are presented. The obtained g-shift
strongly depends on magnetic fields at low temperature, showing a significant
deviation from the previous classical result.Comment: 4 pages, 3 figures,to be published in Phys. Rev. Let
Update on perioperative management of patients undergoing surgery for liver cancer
Hepatocellular carcinoma is often accompanied by chronic hepatitis or cirrhosis. Preoperative evaluation of liver function and postoperative nutritional management are critical in patients with hepatocellular carcinoma who undergo liver surgery. Although the incidence of postoperative complications and death has declined in Japan over the last 10 years, postoperative complications have not been fully overcome. Therefore, surgical procedures and perioperative management must be improved. Accurate preoperative evaluations of liver function, nutrition, inflammation, and body skeletal muscle are required. Determination of the optimal surgical procedure should consider not only tumor characteristics but also the physical reserve of the patient. Nutritional management of chronic liver disorders, especially maintaining protein synthesis for postoperative protein/energy, is important. Prophylactic antibiotics are recommended for short-term use within 24 hours after surgery. Abdominal drainage is recommended for patients with cirrhosis who may develop large amounts of ascites, who are at risk of postoperative bleeding, or who may have bile leakage due to a large resection area. Postoperative exercise therapy may improve insulin resistance in patients with chronic liver damage. Implementation of an early/enhanced recovery after surgery program is recommended to reduce biological invasive responses and achieve early independence of physical activity and nutrition intake. We review the latest information on the perioperative management of patients undergoing liver resection for hepatocellular carcinoma
Role of unstable periodic orbits in phase transitions of coupled map lattices
The thermodynamic formalism for dynamical systems with many degrees of
freedom is extended to deal with time averages and fluctuations of some
macroscopic quantity along typical orbits, and applied to coupled map lattices
exhibiting phase transitions. Thereby, it turns out that a seed of phase
transition is embedded as an anomalous distribution of unstable periodic
orbits, which appears as a so-called q-phase transition in the spatio-temporal
configuration space. This intimate relation between phase transitions and
q-phase transitions leads to one natural way of defining transitions and their
order in extended chaotic systems. Furthermore, a basis is obtained on which we
can treat locally introduced control parameters as macroscopic ``temperature''
in some cases involved with phase transitions.Comment: 13 pages, 9 figures; further explanation and 2 figures are added
(minor revision
Multipole as -Electron Spin-Charge Density in Filled Skutterudites
It is shown that -electron multipole is naturally defined as spin-charge
one-electron density operator in the second-quantized form with the use of
tensor operator on the analogy of multipole expansion of electromagnetic
potential from charge distribution in electromagnetism. Due to this definition
of multipole, it is possible to determine multipole state from a microscopic
viewpoint on the basis of the standard linear response theory for multipole
susceptibility. In order to discuss multipole properties of filled
skutterudites, we analyze a seven-orbital impurity Anderson model by employing
a numerical renormalization group method. We show our results on possible
multipole states of filled skutterudite compounds.Comment: To appear in the Proceedings of International Conference on "New
Quantum Phenomena in Skutterudite and Related Systems" (September 2007, Kobe,
Japan
Seasonal Fluctuation of Polycyclic Aromatic Hydrocarbons and Aerosol Genotoxicity in Long-Range Transported Air Mass Observed at the Western End of Japan
In order to clarify the level transboundary air pollution caused by polycyclic aromatic hydrocarbons (PAHs) and genotoxic substances, aerosols were collected from forest and suburban sites in Nagasaki, west Japan, for 6 years. The PAH concentration was measured, and the genotoxicity of the substances were evaluated using the umu test. The results showed no notable trends in the concentration or toxicity of either sites throughout the study period. The suburban and forest sites shared similar seasonal fluctuation patterns and quantitative values, suggesting that the western end of Japan might be affected by long-range transported pollutants, especially in winter. PAH concentration and genotoxicity showed the same seasonal patterns of increased levels in winter and lower levels in summer. This suggests that PAHs and genotoxic substances were correlated and share common sources. Back trajectory and source analyses were conducted using the diagnostic ratios of PAHs. It was predicted that air pollution by PAHs at the forest site arise predominantly as a result of biomass or coal combustion in continental regions, such as northern parts of China and the Korean Peninsula. This is particularly expected in winter. Therefore, genotoxic substances would also be strongly influenced by transboundary pollution from the continental region. In addition, it was estimated that the contribution of transboundary PAH pollution could reach 70% at the suburban site in winter
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