Clouds, Clumps, Cores & Comets - a Cosmic Chemical Connection?

We discuss the connection between the chemistry of dense interstellar clouds and those characteristics of cometary matter that could be remnants of it. The chemical evolution observed to occur in molecular clouds is summarized and a model for dense core collapse that can plausibly account for the isotopic fractionation of hydrogen, nitrogen, oxygen and carbon measured in primitive solar system materials is presented.Comment: to be published in Advances in Geoscience

Food Security and the Federal Minimum Wage

This working paper, by William M. Rodgers III, Hanley S. Chiang, and Bruce W. Klein, estimates the extent to which increases in the U.S. federal minimum wage in October 1996 and September 1997 improved the ability of households to be food secure -- that is, to purchase for their members an adequate supply of nutritional and safe foods. First, the authors show that the two increases significantly altered the hourly wage distribution of householders (principal person in a household). The shifts were greatest among household heads that are minority, single parents, and household heads with no more than a high school diploma. Even after controlling for the link between the 1990s economic expansion and food security, the October 1996 and September 1997 increases in the federal minimum wage raised food security and reduced hunger, particularly in low-income households where householders had completed no more than a high school degree or were a single parent

Growth and Coagulation in a Herding Model

We discuss various existing models which mimic the herding effect in financial markets and introduce a new model of herding which incorporates both growth and coagulation. In this model, at each time step either (i) with probability p the system grows through the introduction of a new agent or (ii) with probability q=1-p two groups are selected at random and coagulate. We show that the size distribution of these groups has a power law tail with an exponential cut-off. A variant of our basic model is also discussed where rates are proportional to the size of a grou

Solar sustained plasma/absorber conceptual design

A space power system concept was evaluated which uses concentrated solar energy to heat a working fluid to temperatures as high as 4000 K. The high temperature working fluid could be used for efficient electric power production in advanced thermal or magnetohydrodynamic conversion cycles. Energy absorber configurations utilizing particles or cesium vapor absorber material were investigaed. Results of detailed radiant heat transfer calculations indicated approximately 86 percent of the incident solar energy could be absorbed within a 12-cm-dia flowing stream of gas borne carbon particles. Calculated total energy absorption in the cesium vapor seeded absorber configuration ranged from 34 percent to 64 percent of the incident solar energy. Solar flux concentration ratios of between approximately 3000 and 10,000 will be required to sustain absorber temperatures in the range from 3000 K to 4000 K

Chemical chronology of the Southern Coalsack

We demonstrate how the observed H2O ice column densities toward three dense globules in the Southern Coalsack could be used to constrain the ages of these sources. We derive ages of ~10^5 yr, in agreement with dynamical studies of these objects. We have modelled the chemical evolution of the globules, and show how the molecular abundances are controlled by both the gas density and the initial chemical conditions as the globules formed. Based on our derived ages, we predict the column densities of several species of interest. These predictions should be straightforward to test by performing molecular line observationsComment: 10 pages, 4 figures, in press at MNRA

Examining the role of mental health and clinical issues within talent development

Although significant research supports the association between physical activity and mental wellbeing, current literature acknowledges that athletes are no less susceptible to mental illness than the general population. Despite welcomed initiatives aimed at improving mental health within elite sport, these programs often fail to target young athletes; an important concern given that the genesis of many mental illnesses are recognized to occur during this critical period. Given the importance of early intervention and effective treatment, and the potentially devastating consequences of clinical issues going undiagnosed, the implications for talent identification and development become obvious. With this in mind, this study sought to examine the range of mental health issues that may impact upon developing athletes and potential consequences for the development process, specific risk and protective factors associated with talent development, along with an examination of current practices concerning the identification of mental health issues in such environments. Qualitative interviews were conducted with purposively sampled clinicians (n = 8) experienced in working with adolescents and/or young athletes. Inductive content analysis was undertaken, identifying four main themes: key behavioral indicators; associated risk factors; associated protective factors; and issues around identification and diagnosis. Key behavioral indicators included behavioral change, along with behaviors associated with eating disorders, anxiety and depression. Risk factors centered on family background, the performance environment, and issues surrounding adolescence. Protective factors were primarily social in nature. Finally, a lack of awareness and understanding of clinical issues, multiple causes of symptoms, non-disclosure and the need for triangulation of assessment were identified. The need for improved identification and intervention strategies was apparent, with coaches identified as well placed to detect general ‘warning signs’ such as behavioral change. Short of integrating trained clinicians into talent development environments, as part of a triangulation process, ecologically validated assessment tools – coupled with appropriate training and signposting – could offer a practical way of flagging potential issues in developing athletes. The need for the development of such an instrument is therefore apparent. Finally, education around the influential role of family is also recommended in order to promote the protective elements and mitigate risk factors

Analytical design and performance studies of the nuclear light bulb engine

Analytical studies were conducted to investigate in detail the heat balance characteristics of the nuclear light bulb engine. Distributions of energy deposition to all engine components from the fission process, conduction and convection, and thermal radiation were considered. Where uncertainties in basic data or heat transfer characteristics were encountered, ranges of heat loads were calculated and reference values were selected. The influence of these heat loads on engine performance, space radiator requirements, and cooling sequence and cooling circuit designs was determined. The analyses resulted in revisions to the previously reported reference engine characteristics, principally in the heat loads to some engine components and in the cooling sequence. These revisions were incorporated in the engine dynamics digital computer simulation program. No significant changes occurred in the dynamic response of the engine to perturbations in fuel injection rate, reactivity or exhaust nozzle area

Counterinsurgency in the 21st century the foundation and implications of the new U.S. doctrine

In December 2006, the U.S. Army published its new counterinsurgency (COIN) Field Manual (FM 3-24). FM 3-24 is the much-anticipated capstone doctrinal COIN guide for the U.S. Army and Marine Corps. Its intent is "to fill a doctrinal gap" for fighting COIN by delivering "a manual that provides principles and guidelines for counterinsurgency operations." The importance of developing a coherent, interdisciplinary approach that helps to fill the "doctrina" and capability gaps facing the U.S. military in the asymmetrical warfare spectrum, including COIN, cannot be overstated. In light of this, how well do the new guidelines in FM 3-24 for conducting a COIN campaign align with historical and social science lessons on counterinsurgency? FM 3-24 outlines U.S. COIN doctrine in the form of strategies called Logical Lines of Operation (LLOs). With this in mind, are there cases in the Middle East where FM 3-24's LLOs have been applied and produced their intended effects? If they were not used and the state power's desired "endstate" was achieved, what strategies were used to achieve the COIN campaign objectives? This thesis assesses the extent to which the field manual aligns with insights and practices from historical COIN campaigns in the Middle East as well as the new doctrine's ability to supply the United States with a COIN strategy that incorporates insights and conclusions from academia. Our findings indicate that FM 3-24 is a necessary step in developing an effective and coherent U.S. approach to COIN. However, it fails to incorporate some more contemporary social movement theory explanations into its strategies. For example, it fails to recognize the relative importance political inclusion in counterinsurgency strategies versus other variables, such as security, as a primary means of success in counterinsurgency campaigns.http://archive.org/details/counterinsurgenc109453099US Army (USA) authorsApproved for public release; distribution is unlimited.Approved for public release; distribution is unlimited

Short Distance Expansion from the Dual Representation of Infinite Dimensional Lie Algebras

We compute the short distance expansion of fields or operators that live in the coadjoint representation of an infinite dimensional Lie algebra by using only properties of the adjoint representation and its dual. We explicitly compute the short distance expansion for the duals of the Virasoro algebra, affine Lie Algebras and the geometrically realized N-extended supersymmetric GR Virasoro algebra.Comment: 19 pages, LaTeX twice, no figure, replacement has corrected Lie algebr