Safety of Log Transportation After Regulation and Training in the State of Georgia, USA

Mechanical failure rates observed in highway accidents involving logging tractor-trailers have fallen significantly since Georgia subjected these vehicles to random roadside inspections. This improvement is attributed to both the regulation and the training efforts aimed at the log trucking community immediately before and after the implementation of the rules

Microscopic approach to pion-nucleus dynamics

Elastic scattering of pions from finite nuclei is investigated utilizing a contemporary, momentum--space first--order optical potential combined with microscopic estimates of second--order corrections. The calculation of the first--order potential includes:\ \ (1)~full Fermi--averaging integration including both the delta propagation and the intrinsic nonlocalities in the $\pi$-$N$ amplitude, (2)~fully covariant kinematics, (3)~use of invariant amplitudes which do not contain kinematic singularities, and (4)~a finite--range off--shell pion--nucleon model which contains the nucleon pole term. The effect of the delta--nucleus interaction is included via the mean spectral--energy approximation. It is demonstrated that this produces a convergent perturbation theory in which the Pauli corrections (here treated as a second--order term) cancel remarkably against the pion true absorption terms. Parameter--free results, including the delta--nucleus shell--model potential, Pauli corrections, pion true absorption, and short--range correlations are presented. (2 figures available from authors)Comment: 13 page

Library Design in Combinatorial Chemistry by Monte Carlo Methods

Strategies for searching the space of variables in combinatorial chemistry experiments are presented, and a random energy model of combinatorial chemistry experiments is introduced. The search strategies, derived by analogy with the computer modeling technique of Monte Carlo, effectively search the variable space even in combinatorial chemistry experiments of modest size. Efficient implementations of the library design and redesign strategies are feasible with current experimental capabilities.Comment: 5 pages, 3 figure

Neutron Star Constraints on the H Dibaryon

We study the influence of a possible H dibaryon condensate on the equation of state and the overall properties of neutron stars whose population otherwise contains nucleons and hyperons. In particular, we are interested in the question of whether neutron stars and their masses can be used to say anything about the existence and properties of the H dibaryon. We find that the equation of state is softened by the appearance of a dibaryon condensate and can result in a mass plateau for neutron stars. If the limiting neutron star mass is about that of the Hulse-Taylor pulsar a condensate of H dibaryons of vacuum mass 2.2 GeV and a moderately attractive potential in the medium could not be ruled out. On the other hand, if the medium potential were even moderately repulsive, the H, would not likely exist in neutron stars. If neutron stars of about 1.6 solar mass were known to exist, attractive medium effects for the H could be ruled out. Certain ranges of dibaryon mass and potential can be excluded by the mass of the Hulse-Taylor pulsar which we illustrate graphically.Comment: Revised by the addition of a figure showing the region of dibaryon mass and potential excluded by the Hulse-Taylor pulsar. 18 pages, 11 figures, latex (submitted to Phys. Rev. C

Can Doubly Strange Dibaryon Resonances be Discovered at RHIC?

The baryon-baryon continuum invariant mass spectrum generated from relativistic nucleus + nucleus collision data may reveal the existence of doubly-strange dibaryons not stable against strong decay if they lie within a few MeV of threshold. Furthermore, since the dominant component of these states is a superposition of two color-octet clusters which can be produced intermediately in a color-deconfined quark-gluon plasma (QGP), an enhanced production of dibaryon resonances could be a signal of QGP formation. A total of eight, doubly-strange dibaryon states are considered for experimental search using the STAR detector (Solenoidal Tracker at RHIC) at the new Relativistic Heavy Ion Collider (RHIC). These states may decay to Lambda-Lambda and/or proton-Cascade-minus, depending on the resonance energy. STAR's large acceptance, precision tracking and vertex reconstruction capabilities, and large data volume capacity, make it an ideal instrument to use for such a search. Detector performance and analysis sensitivity are studied as a function of resonance production rate and width for one particular dibaryon which can directly strong decay to proton-Cascade-minus but not Lambda-Lambda. Results indicate that such resonances may be discovered using STAR if the resonance production rates are comparable to coalescence model predictions for dibaryon bound states.Comment: 28 pages, 5 figures, revised versio

Flux Pinning and Phase Transitions in Model High-Temperature Superconductors with Columnar Defects

We calculate the degree of flux pinning by defects in model high-temperature superconductors (HTSC's). The HTSC is modeled as a three-dimensional network of resistively-shunted Josephson junctions in an external magnetic field, corresponding to a HTSC in the extreme Type-II limit. Disorder is introduced either by randomizing the coupling between grains (Model A disorder) or by removing grains (Model B disorder). Three types of defects are considered: point disorder, random line disorder, and periodic line disorder; but the emphasis is on random line disorder. Static and dynamic properties of the models are determined by Monte Carlo simulations and by solution of the analogous coupled overdamped Josephson equations in the presence of thermal noise. Random line defects considerably raise the superconducting transition temperature T$_c(B)$, and increase the apparent critical current density J$_c(B,T)$, in comparison to the defect-free crystal. They are more effective in these respects than a comparable volume density of point defects, in agreement with the experiments of Civale {\it et al}. Periodic line defects commensurate with the flux lattice are found to raise T$_c(B)$ even more than do random line defects. Random line defects are most effective when their density approximately equals the flux density. Near T$_c(B)$, our static and dynamic results appear consistent with the anisotropic Bose glass scaling hypotheses of Nelson and Vinokur, but with possibly different critical indices:Comment: 10 pages, LaTeX(REVTeX v3.0, twocolumn), 11 figures (not included

Child Health Research Funding and Policy: Imperatives and Investments for a Healthier World

Although pediatric research enjoyed significant benefits during the National Institutes of Health (NIH) doubling era, the proportion of the NIH budget devoted to the pediatric-research portfolio has declined overall. In light of this declining support for pediatric biomedical research, the Federation of Pediatric Organizations held a topic symposium at the 2009 Pediatric Academic Societies annual meeting as a forum for discussion of the past and future states of funding, the rationale for directing public funds toward the understanding of child health and disease, and new programs and paradigms for promoting child health research. This report of the symposium is intended to disseminate more broadly the information presented and conclusions discussed to encourage those in the child health research community to exert influence with policy makers to increase the allocation of national funding for this underfunded area

Resolving the Antibaryon-Production Puzzle in High-Energy Heavy-Ion Collisions

We argue that the observed antiproton production in heavy-ion collisions at CERN-SpS energies can be understood if (contrary to most sequential scattering approaches) the backward direction in the process $p\bar p \leftrightarrow \bar{n}\pi$ (with $\bar{n}$=5-6) is consistently accounted for within a thermal framework. Employing the standard picture of subsequent chemical and thermal freezeout, which induces an over-saturation of pion number with associated chemical potentials of $\mu_\pi\simeq$~60-80 MeV, enhances the backward reaction substantially. The resulting rates and corresponding cross sections turn out to be large enough to maintain the abundance of antiprotons at chemical freezeout until the decoupling temperature, in accord with the measured $\bar{p}/p$ ratio in Pb(158AGeV)+Pb collisions.Comment: 4 pages ReVTeX incl. 2 eps-figs, minor changes (two figs added, rate eq. written more explicitly), version accepted for publication in PR

On the pion-nucleon coupling constant

In view of persisting misunderstanding about the determination of the pion-nucleon coupling constants in the Nijmegen multienergy partial-wave analyses of pp, np, and pbar-p scattering data, we present additional information which may clarify several points of discussion. We comment on several recent papers addressing the issue of the pion-nucleon coupling constant and criticizing the Nijmegen analyses.Comment: 19 pages, Nijmegen preprint THEF-NYM-92-0