A Survey of Residual Cancer Risks Permitted by Health, Safety and Environmental Policy

The authors describe permitted U.S. residual cancer risks, focusing on numerical levels specifically and implicitly authorized by statute or regulation. They also discuss potential changes

Automatic lightning location system

Hyperbolic triangulation method was used for locating lightning storm path and position from VHF lightning charge emissions. Possible applications in electric power companies, forest fire lookout centers, airports, and pipeline companies are indicated

Vortex macroscopic superpositions in ultracold bosons in a double-well potential

We study macroscopic superpositions in the orbital rather than the spatial degrees of freedom, in a three-dimensional double-well system. We show that the ensuing dynamics of $N$ interacting excited ultracold bosons, which in general requires at least eight single-particle modes and ${N+7 \choose N}$ Fock vectors, is described by a surprisingly small set of many-body states. An initial state with half the atoms in each well, and purposely excited in one of them, gives rise to the tunneling of axisymmetric and transverse vortex structures. We show that transverse vortices tunnel orders of magnitude faster than axisymmetric ones and are therefore more experimentally accessible. The tunneling process generates macroscopic superpositions only distinguishable by their orbital properties and within experimentally realistic times.Comment: 9 pages, 6 figure

Spacetime as a quantum many-body system

Quantum gravity has become a fertile interface between gravitational physics and quantum many-body physics, with its double goal of identifying the microscopic constituents of the universe and their fundamental dynamics, and of understanding their collective properties and how spacetime and geometry themselves emerge from them at macroscopic scales. In this brief contribution, we outline the problem of quantum gravity from this emergent spacetime perspective, and discuss some examples in which ideas and methods from quantum many-body systems have found a central role in quantum gravity research.Comment: 15 pages; invited contribution to "Many-body approaches at different scales: A tribute to Norman H. March on the occasion of his 90th birthday", edited by G. G. N. Angilella and C. Amovilli (New York, Springer, 2017 - to appear

Statistical Description of Hydrodynamic Processes in Ionic Melts with taking into account Polarization Effects

Statistical description of hydrodynamic processes for ionic melts is proposed with taking into account polarization effects caused by the deformation of external ionic shells. This description is carried out by means of the Zubarev nonequilibrium statistical operator method, appropriate for investigations of both strong and weak nonequilibrium processes. The nonequilibrium statistical operator and the generalized hydrodynamic equations that take into account polarization processes are received for ionic-polarization model of ionic molten salts when the nonequilibrium averaged values of densities of ions number, their momentum, dipole momentum and total energy are chosen for the reduced description parameters. A spectrum of collective excitations is investigated within the viscoelastic approximation for ion-polarization model of ionic melts.Comment: 24 pages, RevTex4.1-format, no figure

Cheyenne and Sioux Indian relations along the Oregon Trail

"Summary: The relationship between the Sioux and Cheyenne Indians and the emigrants before the Treaty of Laramie in 1851 may be characterized as fairly amicable in spite of mutual irritations. The Indians were at first surprised and then alarmed at the volume of migration through their territory. This alarm was due to the continual destruction of the game, grass and timber; and the widespread epidemics of measles, smallpox and cholera. Many small fights occurred; yet there was no general movement against the whites, and most of the hostile acts that did occur resulted from the desire of the young men to "score a coup." On the other hand, few emigrant trains escaped the nuisance of Indian visits with their consequent begging and stealing, and there was usually danger for any small party which wandered too far from the trail. These incidental hostilities resulted in the demand that the Government afford protection for the emigrant. The efforts of the Government in this direction, however, were almost ludicrous. By 1850 only three military posts had been established by the Government along the trail that was almost two thousand miles long and these posts were never adequately garrisoned. Dragoons sent out to scour the plains may have impressed the savages at times with the power of the United States, but such lessons were soon forgotten and, therefore, had to be frequently repeated. More protection was supplied by the emigrants themselves and by the very size of the migration. The good will of the Indians was partially secured by promises of subsequent material rewards, which the Government saw t1t to fulfill 1n the Treaty or Laramie. After the Treaty of Laramie the Indians remained true to their obligations to remain at peace and not molest the "llh1tes. This state of things continued until the month of August, 1854, when it was interrupted by the Grattan massacre, an event which was at least partly due to the folly of the military author1t1es. The series of Sioux depredations that followed were brought to a close by another massacre, that of Little Thunder's band by the expedition of General Harney. No sooner had peace been established with the Sioux than serious trouble w1th the Cheyenne began. The series of depredations by them 1n the neighborhood of Fort Kearney can be traced back to the episode of the Pour Horses near the crossing of the North Platte. In order to protect small part.1es on the plains from being attacked by the angry Cheyennes, Agent Twiss arranged for a council with the Cheyenne at which time peace was agreed upon. In spite of this Colonel Sumner was ordered to lead an expedition against the India.11s, which was, on the whole, not very successful, but did possibly have a quieting effect upon them as both the Sioux and Cheyenne remained peaceful during the remainder of the period under consideration. In the last analysis, the history of the Indian relations with the whites during this period is the old story found wherever the white man went. Whether the Indians fought or- whether they made a treaty, they eventually forfeited their rights and lost their territory."--Pages 82-84

Symmetry breaking and singularity structure in Bose-Einstein condensates

We determine the trajectories of vortex singularities that arise after a single vortex is broken by a discretely symmetric impulse in the context of Bose-Einstein condensates in a harmonic trap. The dynamics of these singularities are analyzed to determine the form of the imprinted motion. We find that the symmetry-breaking process introduces two effective forces: a repulsive harmonic force that causes the daughter trajectories to be ejected from the parent singularity, and a Magnus force that introduces a torque about the axis of symmetry. For the analytical non-interacting case we find that the parent singularity is reconstructed from the daughter singularities after one period of the trapping frequency. The interactions between singularities in the weakly interacting system do not allow the parent vortex to be reconstructed. Analytic trajectories were compared to the actual minima of the wavefunction, showing less 0.5% error for impulse strength of (v=0.00005). We show that these solutions are valid within the impulse regime for various impulse strengths using numerical integration of the Gross-Pitaevskii equation. We also show that the actual duration of the symmetry breaking potential does not significantly change the dynamics of the system as long as the strength is below (v=0.0005).Comment: 14 pages, 10 figure

Statistical correlations of an anyon liquid at low temperatures

Using a proposed generalization of the pair distribution function for a gas of non-interacting particles obeying fractional exclusion statistics in arbitrary dimensionality, we derive the statistical correlations in the asymptotic limit of vanishing or low temperature. While Friedel-like oscillations are present in nearly all non-bosonic cases at T=0, they are characterized by exponential damping at low temperature. We discuss the dependence of these features on dimensionality and on the value of the statistical parameter alpha.Comment: to appear in Phys. Chem. Liquid

Dynamical Realization of Macroscopic Superposition States of Cold Bosons in a Tilted Double Well

We present exact expressions for the quantum sloshing of Bose-Einstein condensates in a tilted two-well potential. Tunneling is suppressed by a small potential difference between wells, or tilt. However, tunneling resonances occur for critical values of the tilt when the barrier is high. At resonance, tunneling times on the order of 10-100 ms are possible. Furthermore, such tilted resonances lead to a dynamical scheme for creating few-body NOON-like macroscopic superposition states which are protected by the many body wavefunction against potential fluctuations.Comment: 6 pages, 5 figures, final version, only minor changes from previous arXiv versio