Prompt activation analysis of coal and iron ore

Prepared for U.S. Dept. of Mines, Bureau of MinesAlso issued as a M.S. thesis in the Dept. of Nuclear Engineering, 1970Includes bibliographical references (leaf 47)H018089

Florida Takeover Law: Control-Share Acquisitions

Under Florida\u27s new control-share acquisition law, a shareholder\u27s right to vote will be determined in certain circumstances by a vote of the other shareholders. Merrs. [sic] Rasmussen and Fuller contend that the commerce clause precludes the law\u27s interference with interstate commerce, that the law might be preempted by the Williams Act, and that the law\u27s validity is questionable on other constitutional grounds. The authors also suggest answers to the may questions they raise regarding ambiguities in the law, and offer advice for both potential targets and stock acquirers on how to comply with the law

Florida Takeover Law: Affiliated Transactions

Many states perceive corporate takeover activity as a threat to local business and industry. The Florida Affiliated Transactions Statute is one part of a comprehensive scheme of anti-takeover regulation in Florida. The authors of this Article explain the development of American takeover regulation, analyze this statute, and discuss surrounding constitutional and public policy issues

Effects of Different Convection Models Upon the High-Latitude Ionosphere

It is well known that convection electric fields have an important effect on the ionosphere at high latitudes and that a quantitative understanding of their effect requires a knowledge of plasma convection over the entire high-latitude region. Two empirical models of plasma convection that have been proposed for use in studying the ionosphere are the Volland and Heelis models. Both of these models provide a similar description of two-celled ionospheric convection, but they differ in several ways, in particular, in the manner in which plasma flows over the central polar cap and near the polar cap boundary. In order to obtain a better understanding of the way in which these two models affect the ionosphere, two separate runs of our high-latitude, time-dependent ionospheric model were made, with only the convection models distinguishing the two runs. It was found that the two models lead to differences in the ionosphere but often the differences are subtle and are swamped by universal time effects. The most notable differences are in predictions of the height of the F2 peak and in the ion temperature, particularly along the evening polar cap boundary and in the cusp region. For these two parameters, the differences caused by the two different convection models dominate the universal time effects. One question that arises is whether one could examine measurements of plasma density and temperature and determine which of the two convection models most accurately represents actual ionospheric convection. Unfortunately, it is expected that when the effects of other ionospheric inputs are considered, such as the neutral wind, the uncertainties are sufficiently large that the characteristic differences between the Volland and Heelis convection models cannot be clearly identified in an examination of plasma density and temperature measurements

Non-covalent interactions across organic and biological subsets of chemical space: Physics-based potentials parametrized from machine learning

Classical intermolecular potentials typically require an extensive parametrization procedure for any new compound considered. To do away with prior parametrization, we propose a combination of physics-based potentials with machine learning (ML), coined IPML, which is transferable across small neutral organic and biologically-relevant molecules. ML models provide on-the-fly predictions for environment-dependent local atomic properties: electrostatic multipole coefficients (significant error reduction compared to previously reported), the population and decay rate of valence atomic densities, and polarizabilities across conformations and chemical compositions of H, C, N, and O atoms. These parameters enable accurate calculations of intermolecular contributions---electrostatics, charge penetration, repulsion, induction/polarization, and many-body dispersion. Unlike other potentials, this model is transferable in its ability to handle new molecules and conformations without explicit prior parametrization: All local atomic properties are predicted from ML, leaving only eight global parameters---optimized once and for all across compounds. We validate IPML on various gas-phase dimers at and away from equilibrium separation, where we obtain mean absolute errors between 0.4 and 0.7 kcal/mol for several chemically and conformationally diverse datasets representative of non-covalent interactions in biologically-relevant molecules. We further focus on hydrogen-bonded complexes---essential but challenging due to their directional nature---where datasets of DNA base pairs and amino acids yield an extremely encouraging 1.4 kcal/mol error. Finally, and as a first look, we consider IPML in denser systems: water clusters, supramolecular host-guest complexes, and the benzene crystal.Comment: 15 pages, 9 figure

The Role of the IMF in Future Sovereign Debt Restructurings: Report of the Annenberg House Expert Group

A meeting of international finance and insolvency experts was held on November 2, 2013 at the Annenberg House in Santa Monica, California. The meeting was co-hosted by the USC Law School and the Annenberg Retreat at Sunnylands. The goal was to solicit the views of experts on the implications of the IMF’s April 26, 2013 paper captioned “Sovereign Debt Restructuring -- Recent Developments and Implications for the Fund’s Legal and Policy Framework”. The April 26 paper may signal a shift in IMF policies in the area of sovereign debt workouts. Although the Expert Group discussed a number of the ideas contained in the April 26 paper, attention focused on paragraph 32 of that paper. That paragraph states in relevant part: “There may be a case for exploring additional ways to limit the risk that Fund resources will simply be used to bail out private creditors. For example, a presumption could be established that some form of a creditor bail-in measure would be implemented as a condition for Fund lending in cases where, although no clear-cut determination has been made that the debt is unsustainable, the member has lost market access and prospects for regaining market access are uncertain.” This Report summarizes the consensus views of the Expert Group on the practical implications of the suggestions contained in paragraph 32 of the April 26 paper

Live-virus exposure of vaccine-protected macaques alters the anti-HIV-1 antibody repertoire in the absence of viremia

Background: We addressed the question whether live-virus challenges could alter vaccine-induced antibody (Ab) responses in vaccinated rhesus macaques (RMs) that completely resisted repeated exposures to R5-tropic simian-human immunodeficiency viruses encoding heterologous HIV clade C envelopes (SHIV-Cs). Results: We examined the Ab responses in aviremic RMs that had been immunized with a multi-component protein vaccine (multimeric HIV-1 gp160, HIV-1 Tat and SIV Gag-Pol particles) and compared anti-Env plasma Ab titers before and after repeated live-virus exposures. Although no viremia was ever detected in these animals, they showed significant increases in anti-gp140 Ab titers after they had encountered live SHIVs. When we investigated the dynamics of anti-Env Ab titers during the immunization and challenge phases further, we detected the expected, vaccine-induced increases of Ab responses about two weeks after the last protein immunization. Remarkably, these titers kept rising during the repeated virus challenges, although no viremia resulted. In contrast, in vaccinated RMs that were not exposed to virus, anti-gp140 Ab titers declined after the peak seen two weeks after the last immunization. These data suggest boosting of pre-existing, vaccine-induced Ab responses as a consequence of repeated live-virus exposures. Next, we screened polyclonal plasma samples from two of the completely protected vaccinees by peptide phage display and designed a strategy that selects for recombinant phages recognized only by Abs present after – but not before – any SHIV challenge. With this “subtractive biopanning” approach, we isolated V3 mimotopes that were only recognized after the animals had been exposed to live virus. By detailed epitope mapping of such anti-V3 Ab responses, we showed that the challenges not only boosted pre-existing binding and neutralizing Ab titers, but also induced Abs targeting neo-antigens presented by the heterologous challenge virus. Conclusions: Anti-Env Ab responses induced by recombinant protein vaccination were altered by the multiple, live SHIV challenges in vaccinees that had no detectable viral loads. These data may have implications for the interpretation of “vaccine only” responses in clinical vaccine trials

The flow of plasma in the solar terrestrial environment

The overall goal of our NASA Theory Program was to study the coupling, time delays, and feedback mechanisms between the various regions of the solar-terrestrial system in a self-consistent, quantitative manner. To accomplish this goal, it will eventually be necessary to have time-dependent macroscopic models of the different regions of the solar-terrestrial system and we are continually working toward this goal. However, with the funding from this NASA program, we concentrated on the near-earth plasma environment, including the ionosphere, the plasmasphere, and the polar wind. In this area, we developed unique global models that allowed us to study the coupling between the different regions. These results are highlighted in the next section. Another important aspect of our NASA Theory Program concerned the effect that localized 'structure' had on the macroscopic flow in the ionosphere, plasmasphere, thermosphere, and polar wind. The localized structure can be created by structured magnetospheric inputs (i.e., structured plasma convection, particle precipitation or Birkland current patterns) or time variations in these input due to storms and substorms. Also, some of the plasma flows that we predicted with our macroscopic models could be unstable, and another one of our goals was to examine the stability of our predicted flows. Because time-dependent, three-dimensional numerical models of the solar-terrestrial environment generally require extensive computer resources, they are usually based on relatively simple mathematical formulations (i.e., simple MHD or hydrodynamic formulations). Therefore, another goal of our NASA Theory Program was to study the conditions under which various mathematical formulations can be applied to specific solar-terrestrial regions. This could involve a detailed comparison of kinetic, semi-kinetic, and hydrodynamic predictions for a given polar wind scenario or it could involve the comparison of a small-scale particle-in-cell (PIC) simulation of a plasma expansion event with a similar macroscopic expansion event. The different mathematical formulations have different strengths and weaknesses and a careful comparison of model predictions for similar geophysical situations provides insight into when the various models can be used with confidence

What is the Source of Observed Annual Variations in Plasmaspheric Density?

Plasmaspheric densities have been observed previously to be higher in December than in June, with the ratio varying between 1.5 and 3.0 and with larger variations at lower L shells. In order to search for the cause of the observed annual variations, we have modeled plasmaspheric density, using a time-dependent hydrodynamic model. On an L = 2 field line with geomagnetic longitude equal to 300°, the modeled plasmaspheric densities were a factor of 1.5 times higher in December than in June. The modeled December to June density ratio was found to increase slightly with L shell, in contrast to observations; this discrepancy may be due to the fact that outer plasmaspheric flux tubes are never completely full. In addition, for an L = 2 field line with geomagnetic longitude equal to 120°, the modeled plasmaspheric density was higher in June than in December by a factor of about 1.2. Various numerical tests were also performed in order to examine the sensitivity of plasmaspheric density to various parameters. In particular, a large vertical neutral wind was applied in order to raise the O+ profile, which had the effect of raising plasmaspheric density by a factor of 6. This in conjunction with a theoretical analysis suggests that plasmaspheric density levels are very sensitive to O+ levels in the upper ionosphere. We conclude that annual variations in plasmaspheric density are due to similar variations in ionospheric O+