4,968 research outputs found
Lorentz-violating contributions of the Carroll-Field-Jackiw model to the CMB anisotropy
We study the finite temperature properties of the
Maxwell-Carroll-Field-Jackiw (MCFJ) electrodynamics for a purely spacelike
background. Starting from the associated finite temperature partition function,
a modified black body spectral distribution is obtained. We thus show that, if
the CMB radiation is described by this model, the spectrum presents an
anisotropic angular energy density distribution. We show, at leading order,
that the Lorentz-breaking contributions for the Planck's radiation law and for
the Stefan-Boltzmann's law are nonlinear in frequency and quadratic in
temperature, respectively. Using our results, we set up bounds for the
Lorentz-breaking parameter, and show that Lorentz violation in the context of
the MCFJ model is unable to yield the known CMB anisotropy (of 1 part in
Zeroth Law compatibility of non-additive thermodynamics
Non-extensive thermodynamics was criticized among others by stating that the
Zeroth Law cannot be satisfied with non-additive composition rules. In this
paper we determine the general functional form of those non-additive
composition rules which are compatible with the Zeroth Law of thermodynamics.
We find that this general form is additive for the formal logarithms of the
original quantities and the familiar relations of thermodynamics apply to
these. Our result offers a possible solution to the longstanding problem about
equilibrium between extensive and non-extensive systems or systems with
different non-extensivity parameters.Comment: 18 pages, 1 figur
Ferrofluids as thermal ratchets
Colloidal suspensions of ferromagnetic nano-particles, so-called ferrofluids,
are shown to be suitable systems to demonstrate and investigate thermal ratchet
behavior: By rectifying thermal fluctuations, angular momentum is transferred
to a resting ferrofluid from an oscillating magnetic field without net rotating
component. Via viscous coupling the noise driven rotation of the microscopic
ferromagnetic grains is transmitted to the carrier liquid to yield a
macroscopic torque. For a simple setup we analyze the rotation of the
ferrofluid theoretically and show that the results are compatible with the
outcome of a simple demonstration experiment.Comment: 4 pages, 3 figures, corrected version, improved figures, to be
published in Phys. Rev. Let
Rectification of thermal fluctuations in ideal gases
We calculate the systematic average speed of the adiabatic piston and a
thermal Brownian motor, introduced in [Van den Broeck, Kawai and Meurs,
\emph{Microscopic analysis of a thermal Brownian motor}, to appear in Phys.
Rev. Lett.], by an expansion of the Boltzmann equation and compare with the
exact numerical solution.Comment: 18 page
Fast-ion conduction and flexibility of glassy networks
We observe two thresholds in the variations of electrical conductivity of dry
solid electrolyte (AgI)x(AgPO3)1-x glasses, when the AgI additive concentration
x increases to 9.5% and to 37.8%. Raman scattering complemented by calorimetric
measurements confirm that these thresholds are signatures of the rigidity phase
transitions; at x = 9.5% from a stressed rigid to an isostatically (stress
free) rigid phase, and at x = 37.8% from isostatically rigid to a flexible
phase. In the flexible phase, the electrical conductivity seems to increase as
a power of x, this is in good agreement with the theoretical prediction based
on 3d percolation.Comment: Accepted by PR
Coulomb Zero-Bias Anomaly: A Semiclassical Calculation
Effective action is proposed for the problem of Coulomb blocking of
tunneling. The approach is well suited to deal with the ``strong coupling''
situation near zero bias, where perturbation theory diverges. By a
semiclassical treatment, we reduce the physics to that of electrodynamics in
imaginary time, and express the anomaly through exact conductivity of the
system and exact interaction. For the diffusive anomaly, we
compare the result with the perturbation theory of Altshuler, Aronov, and Lee.
For the metal-insulator transition we derive exact relation of the anomaly and
critical exponent of conductivity.Comment: 9 pages, RevTeX 3.
Mechanical tuning of the evaporation rate of liquid on crossed fibers
We investigate experimentally the drying of a small volume of perfectly
wetting liquid on two crossed fibers. We characterize the drying dynamics for
the three liquid morphologies that are encountered in this geometry: drop,
column and a mixed morphology, in which a drop and a column coexist. For each
morphology, we rationalize our findings with theoretical models that capture
the drying kinetics. We find that the evaporation rate depends significantly on
the liquid morphology and that the drying of liquid column is faster than the
evaporation of the drop and the mixed morphology for a given liquid volume.
Finally, we illustrate that shearing a network of fibers reduces the angle
between them, changes the morphology towards the column state, and so enhances
the drying rate of a volatile liquid deposited on it
Nuclear medium modifications of the NN interaction via quasielastic () and () scattering
Within the relativistic PWIA, spin observables have been recalculated for
quasielastic () and () reactions on a Ca
target. The incident proton energy ranges from 135 to 300 MeV while the
transferred momentum is kept fixed at 1.97 fm^{-1}. In the present
calculations, new Horowitz-Love--Franey relativistic NN amplitudes have been
generated in order to yield improved and more quantitative spin observable
values than before. The sensitivities of the various spin observables to the NN
interaction parameters, such as (1) the presence of the surrounding nuclear
medium, (2) a pseudoscalar versus a pseudovector interaction term, and (3)
exchange effects, point to spin observables which should preferably be measured
at certain laboratory proton energies, in order to test current nuclear models.
This study also shows that nuclear medium effects become more important at
lower proton energies ( 200 MeV). A comparison to the limited available
data indicates that the relativistic parametrization of the NN scattering
amplitudes in terms of only the five Fermi invariants (the SVPAT form) is
questionable.Comment: 10 pages, 6 Postscript figures, uses psfig.sty and article.sty,
submitted to Phys. Rev.
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Everolimus Exposure as a Predictor of Toxicity in Renal Cell Cancer Patients in the Adjuvant Setting: Results of a Pharmacokinetic Analysis for SWOG S0931 (EVEREST), a Phase III Study (NCT01120249).
BackgroundS0931 is assessing recurrence-free survival in renal cell carcinoma (RCC) patients randomized to receive everolimus (EVE) versus placebo for one year following nephrectomy. Due to a higher than expected dropout rate, we assessed EVE trough levels in the adjuvant setting to evaluate the relationship between EVE exposure and probability of toxicity.MethodsPatients received 10 mg daily EVE for nine 6-week cycles. Pre-dose whole blood samples were collected pre-cycle 2 and pre-cycle 3 and analyzed for EVE. Patients with pre-cycle 2 and/or pre-cycle 3 EVE results were used in the analysis. Patients were segregated into quartiles (Q) based on EVE levels and logistic regression was used to model the most common adverse event outcomes using EVE trough as a predictor. Hazard and odds ratios were adjusted for age, BMI and performance status.ResultsA total of 467 patients were included in this analysis. Quartiles normalized to an EVE dose of 10 mg/day were < 9.0, 9.0-12.9, 12.9-22.8, and > 22.8 ng/mL, respectively. EVE trough levels increased with increasing age (p < 0.001). Furthermore, EVE trough levels were higher in men than women (19.4 versus 15.4 ng/mL, p = 0.01). Risk of grade 2 + triglycerides was increased in Q2 and Q3 vs Q1 (OR = 2.08; p = 0.02 and OR = 2.63; p = 0.002). Risk of grade 2 + rash was increased in Q2 and Q4 vs Q1 (OR = 2.99; p = 0.01 and OR = 2.90; p = 0.02). There was also an increased risk of any grade 3 + tox in Q2 vs Q1 (OR = 1.71; p = 0.05).ConclusionsWe identified significant gender and age-related differences in EVE trough levels in patients receiving adjuvant treatment for RCC. Furthermore, our analysis identified significant associations between EVE exposure and probability of toxicity
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