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Late biological effects from internal and external exposure
Information on late biological effects of radiation was obtained from the long-term medical followup of a small population of Marshallese accidentally exposed to radioactive fallout from a thermonuclear test in 1954. Endocrine data are compatible with a sequence of nonstochastic radiation effects. The ingestion of radioisotopes of iodine produced clinical thyroid hypofunction in children, biochemical evidence of thyroid dysfunction in some adults, thyroid adenomatous module formation, and, as a possible indirect effect of thyroid damage, at least two cases of pituitary adenoma. In contrast, the only evidence of a stochastic effect has been a real increase in thyroid cancers among the more highly exposed people of Rongelap, none of whom have evidence of residual disease. While three nonthyroidal cancers which are known to be inducible in humans by external irradiation have been documented in the exposed population, three similar cancers have occurred in an unexposed comparison population of Marshallese. Nonstochastic effects of radiation exposure may be common but subtle. In the Marshallese experience the morbidity of delayed nonstochastic effects far exceeds that of the stochastic. 20 refs., 5 figs., 1 tab
Production mechanisms and single-spin asymmetry for kaons in high energy hadron-hadron collisions
Direct consequences on kaon production of the picture proposed in a recent
Letter and subsequent publications are discussed. Further evidence supporting
the proposed picture is obtained. Comparison with the data for the inclusive
cross sections in unpolarized reactions is made. Quantitative results for the
left-right asymmetry in single-spin processes are presented.Comment: 10 pages, 2 Postscript figure
Fuzzy Rings in D6-Branes and Magnetic Field Background
We use the Myers T-dual nonabelin Born-Infeld action to find some new
nontrivial solutions for the branes in the background of D6-branes and Melvin
magnetic tube field. In the D6-Branes background we can find both of the fuzzy
sphere and fuzzy ring solutions, which are formed by the gravitational
dielectric effect. We see that the fuzzy ring solution has less energy then
that of the fuzzy sphere. Therefore the fuzzy sphere will decay to the fuzzy
ring configuration. In the Melvin magnetic tube field background there does not
exist fuzzy sphere while the fuzzy ring configuration may be formed by the
magnetic dielectric effect. The new solution shows that propagating in
the D6-branes and magnetic tube field background may expand into a rotating
fuzzy ring. We also use the Dirac-Born-Infeld action to construct the ring
configuration from the D-branes.Comment: Latex, 15 pages, detailed comments in section 2, typos correcte
Phase resolution limit in macroscopic interference between Bose-Einstein condensates
We study the competition between phase definition and quantum phase
fluctuations in interference experiments between independently formed Bose
condensates. While phase-sensitive detection of atoms makes the phase
progressively better defined, interactions tend to randomize it faster as the
uncertainty in the relative particle number grows. A steady state is reached
when the two effects cancel each other. Then the phase resolution saturates to
a value that grows with the ratio between the interaction strength and the atom
detection rate, and the average phase and number begin to fluctuate
classically. We discuss how our study applies to both recently performed and
possible future experiments.Comment: 4 pages, 5 figure
Trapped ions in the strong excitation regime: ion interferometry and non--classical states
The interaction of a trapped ion with a laser beam in the strong excitation
regime is analyzed. In this regime, a variety of non--classical states of
motion can be prepared either by using laser pulses of well defined area, or by
an adiabatic passage scheme based on the variation of the laser frequency. We
show how these states can be used to investigate fundamental properties of
quantum mechanics. We also study possible applications of this system to build
an ion interferometer.Comment: 9 pages, Revtex format, 5 compressed postscript figure
Chaos and flights in the atom-photon interaction in cavity QED
We study dynamics of the atom-photon interaction in cavity quantum
electrodynamics (QED), considering a cold two-level atom in a single-mode
high-finesse standing-wave cavity as a nonlinear Hamiltonian system with three
coupled degrees of freedom: translational, internal atomic, and the field. The
system proves to have different types of motion including L\'{e}vy flights and
chaotic walkings of an atom in a cavity. It is shown that the translational
motion, related to the atom recoils, is governed by an equation of a parametric
nonlinear pendulum with a frequency modulated by the Rabi oscillations. This
type of dynamics is chaotic with some width of the stochastic layer that is
estimated analytically. The width is fairly small for realistic values of the
control parameters, the normalized detuning and atomic recoil
frequency . It is demonstrated how the atom-photon dynamics with a
given value of depends on the values of and initial
conditions. Two types of L\'{e}vy flights, one corresponding to the ballistic
motion of the atom and another one corresponding to small oscillations in a
potential well, are found. These flights influence statistical properties of
the atom-photon interaction such as distribution of Poincar\'{e} recurrences
and moments of the atom position . The simulation shows different regimes of
motion, from slightly abnormal diffusion with at to a superdiffusion with at that
corresponds to a superballistic motion of the atom with an acceleration. The
obtained results can be used to find new ways to manipulate atoms, to cool and
trap them by adjusting the detuning .Comment: 16 pages, 7 figures. To be published in Phys. Rev.
Monte Carlo reconstruction of the inflationary potential
We present Monte Carlo reconstruction, a new method for ``inverting''
observational data to constrain the form of the scalar field potential
responsible for inflation. This stochastic technique is based on the flow
equation formalism and has distinct advantages over reconstruction methods
based on a Taylor expansion of the potential. The primary ansatz required for
Monte Carlo reconstruction is simply that inflation is driven by a single
scalar field. We also require a very mild slow roll constraint, which can be
made arbitrarily weak since Monte Carlo reconstruction is implemented at
arbitrary order in the slow roll expansion. While our method cannot evade
fundamental limits on the accuracy of reconstruction, it can be simply and
consistently applied to poor data sets, and it takes advantage of the attractor
properties of single-field inflation models to constrain the potential outside
the small region directly probed by observations. We show examples of Monte
Carlo reconstruction for data sets similar to that expected from the Planck
satellite, and for a hypothetical measurement with a factor of five better
parameter discrimination than Planck.Comment: 10 pages, 5 figures (RevTeX 4) Version submitted to PRD: references
added, minor clarification
Hydrostatic pressure-induced modifications of structural transitions lead to large enhancements of magnetocaloric effects in MnNiSi-based systems
A remarkable decrease of the structural transition temperature of MnNiSi from 1200 to transitions, leading to a large magnetocaloric effect near room temperature. Application of relatively low hydrostatic pressures (âŒ2.4 kbar) lead to an extraordinary enhancement of the isothermal entropy change from -ÎS=44 to 89 J/kgK at ambient and 2.4 kbar applied pressures, respectively, for a field change of ÎB=5T, and is associated with a large relative volume change of about 7% with P=2.4 kbar
Inflationary perturbations from a potential with a step
We use a numerical code to compute the density perturbations generated during
an inflationary epoch which includes a spontaneous symmetry breaking phase
transition. A sharp step in the inflaton potential generates dependent
oscillations in the spectrum of primordial density perturbations. The amplitude
and extent in wavenumber of these oscillations depends on both the magnitude
and gradient of the step in the inflaton potential. We show that observations
of the cosmic microwave background anisotropy place strong constraints on the
step parameters.Comment: 6 pages, Revtex - v2. reference adde
Long time dynamics and coherent states in nonlinear wave equations
We discuss recent progress in finding all coherent states supported by
nonlinear wave equations, their stability and the long time behavior of nearby
solutions.Comment: bases on the authors presentation at 2015 AMMCS-CAIMS Congress, to
appear in Fields Institute Communications: Advances in Applied Mathematics,
Modeling, and Computational Science 201
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