Faster wash-out and recovery for desflurane vs sevoflurane in morbidly obese patients when no premedication is used

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Aging in the Relaxor Ferroelectric PMN/PT

The relaxor ferroelectric (PbMn$_{1/3}$Nb$_{2/3}$O$_3$)$_{1-x}$(PbTiO$_3$)$_{x}$, $x=0.1$, (PMN/PT(90/10)) is found to exhibit several regimes of complicated aging behavior. Just below the susceptibility peak there is a regime exhibiting rejuvenation but little memory. At lower temperature, there is a regime with mainly cumulative aging, expected for simple domain-growth. At still lower temperature, there is a regime with both rejuvenation and memory, reminiscent of spin glasses. PMN/PT (88/12) is also found to exhibit some of these aging regimes. This qualitative aging behavior is reminiscent of that seen in reentrant ferromagnets, which exhibit a crossover from a domain-growth ferromagnetic regime into a reentrant spin glass regime at lower temperatures. These striking parallels suggest a picture of competition in PMN/PT (90/10) between ferroelectric correlations formed in the domain-growth regime with glassy correlations formed in the spin glass regime. PMN/PT (90/10) is also found to exhibit frequency-aging time scaling of the time-dependent part of the out-of-phase susceptibility for temperatures 260 K and below. The stability of aging effects to thermal cycles and field perturbations is also reported.Comment: 8 pages RevTeX4, 11 figures; submitted to Phys. Rev.

Reply to Comment on "Quantum dense key distribution"

In this Reply we propose a modified security proof of the Quantum Dense Key Distribution protocol detecting also the eavesdropping attack proposed by Wojcik in his Comment.Comment: To appear on PRA with minor change

Nontrivial dependence of dielectric stiffness and SHG on dc bias in relaxors and dipole glasses

Dielectric permittivity and Second Harmonic Generation (SHG) studies in the field-cooled mode show a linear dependence of dielectric stiffness (inverse dielectric permittivity) on dc bias in PMN-PT crystals and SHG intensity in KTaO$_{3}$:Li at small Li concentrations. We explain this unusual result in the framework of a theory of transverse, hydrodynamic-type, instability of local polarization.Comment: 5 figure

Thermodynamic and dynamic anomalies for a three dimensional isotropic core-softened potential

Using molecular dynamics simulations and integral equations (Rogers-Young, Percus-Yevick and hypernetted chain closures) we investigate the thermodynamic of particles interacting with continuous core-softened intermolecular potential. Dynamic properties are also analyzed by the simulations. We show that, for a chosen shape of the potential, the density, at constant pressure, has a maximum for a certain temperature. The line of temperatures of maximum density (TMD) was determined in the pressure-temperature phase diagram. Similarly the diffusion constant at a constant temperature, $D$, has a maximum at a density $\rho_{max}$ and a minimum at a density $\rho_{min}<\rho_{max}$. In the pressure-temperature phase-diagram the line of extrema in diffusivity is outside of TMD line. Although in this interparticle potential lacks directionality, this is the same behavior observed in SPC/E water.Comment: 16 page

Uso de geotecnologias para o apoio ao planejamento de inventários florestais em pequenas propriedades.

Resumo

Obscuration and Origin of Nuclear X-ray emission in FR I Radio Galaxies

We present X-ray observations of the nuclear region of 25 Fanaroff-Riley I radio galaxies from the 3CRR and B2 catalogs, using data from the Chandra and XMM archives. We find the presence of a X-ray Central Compact Core (CCCX) in 13/25 sources, in 3/25 sources the detection of a CCCX is uncertain, while in the remaining 9/25 sources no CCCX is found. All the sources are embedded in a diffuse soft X-ray component, generally on kpc-scales, which is in agreement with the halo of the host galaxy and/or with the intracluster medium. The X-ray spectra of the cores are described by a power law with photon indices Gamma=1.1 - 2.6. In 8 sources excess absorption over the Galactic value is detected, with rest-frame column densities N_H^z ~ 10^20 - 10^21 cm^-2; thus, we confirm the previous claim based on optical data that most FRI radio galaxies lack a standard optically-thick torus. We find significant correlations between the X-ray core luminosity and the radio and optical luminosities, suggesting that at least a fraction of the X-ray emission originates in a jet; however, the origin of the X-rays remains ambiguous. If the X-ray emission is entirely attributed to an isotropic, accretion-related component, we find very small Eddington ratios, L_bol/L_Edd ~ 10^-3 - 10^-8, and we calculate the radiative efficiency to be eta ~ 10^-2 - 10^-6, based on the Bondi accretion rates from the spatial analysis. This suggests that radiatively inefficient accretion flows are present in the cores of low-power radio galaxies.Comment: 20 pages, 7 figures, accepted for publication in The Astrophysical Journa

Dielectric nonlinearity of relaxor ferroelectric ceramics at low ac drives

Dielectric nonlinear response of (PbMg$_{1/3}$Nb$_{2/3}$O$_3$)$_{0.9}$(PbTiO$_3$)$_{0.1}$ (0.9PMN-0.1PT) relaxor ceramics was investigated under different ac drive voltages. It was observed that: (i) the dielectric permittivity is independent on ac field amplitude at high temperatures; (ii) with increasing ac drive, the permittivity maximum increases, and the temperature of the maximum shifts to lower temperature; (iii) the nonlinear effect is weakened when the measurement frequency increases. The influences of increasing ac drive were found to be similar to that of decreasing frequency. It is believed that the dielectric nonlinearities of relaxors at low drives can be explained by the phase transition theory of ergodic space shrinking in succession. A Monte Carlo simulation was performed on the flips of micro polarizations at low ac drives to verify the theory.Comment: Submitted to J. Phys.: Cond. Matte

Barkhausen Noise in a Relaxor Ferroelectric

Barkhausen noise, including both periodic and aperiodic components, is found in and near the relaxor regime of a familiar relaxor ferroelectric, PbMg$_{1/3}$Nb$_{2/3}$O$_3$, driven by a periodic electric field. The temperature dependences of both the amplitude and spectral form show that the size of the coherent dipole moment changes shrink as the relaxor regime is entered, contrary to expectations based on some simple models.Comment: 4 pages RevTeX4, 5 figures; submitted to Phys Rev Let