437 research outputs found

    A Methodological Framework for Parametric Combat Analysis

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    This work presents a taxonomic structure for understanding the tension between certain factors of stability for game-theoretic outcomes such as Nash optimality, Pareto optimality, and balance optimality and then applies such game-theoretic concepts to the advancement of strategic thought on spacepower. This work successfully adapts and applies combat modeling theory to the evaluation of cislunar space conflict. This work provides evidence that the reliability characteristics of small spacecraft share similarities to the reliability characteristics of large spacecraft. Using these novel foundational concepts, this dissertation develops and presents a parametric methodological framework capable of analyzing the efficacy of heterogeneous force compositions in the context of space warfare. This framework is shown to be capable of predicting a stochastic distribution of numerical outcomes associated with various modes of conflict and parameter values. Furthermore, this work demonstrates a general alignment in results between the game-theoretic concepts of the framework and Media Interaction Warfare Theory in terms of evaluating force efficacy, providing strong evidence for the validity of the methodological framework presented in this dissertation

    The effects of alcohol, partner type and impulsivity on sexual risk-taking behavior in college-age women

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    With the AIDS and STD epidemic on the rise, the concern for young people?s risky behavior in sexual situations becomes a crucial issue. Numerous studies have found that alcohol influences risky sexual behavior, but other factors seem to play a role as well. The current study examines participants? perceptions of different partner types (new, casual and steady) and alcohol consumption on the likelihood of condom use in hypothetical situations in vignettes. In addition, participant self-reports of alcohol consumption and their scores on impulsivity scales were correlated to condom use self-efficacy scores and self-reported condom use. A 2x3 MANOVA was conducted using two levels of alcohol (alcohol/no alcohol) and three levels of sexual partner types (new, casual, steady) in a vignette randomly assigned to female college students. Perception of risk, importance in condom use, and likelihood of the characters to suggest the use of a condom were rated on a 5-point Likert scale. Two regression equations were also conducted with the first one measuring the participants? history of alcohol use in the past three months, level of impulsivity and condom use self-efficacy. The second equation included these three scales as well as participant-reported actual condom use in the past three months. A significant main effect in the alcohol condition was found in the MANOVA as well as a main effect in partner type. A significant interaction was also found in the MANOVA. Specifically, a univariate analysis revealed a main effect in partner type for the vignette question rating the participants? perception of the situation risk; participants perceived a situation to be higher in risk when the male is a new partner than when he is a steady partner. The univariate analysis also revealed a main effect in the alcohol condition as well as an interaction in the vignette question measuring the participants? expectation of the female character suggesting the use of a condom. Participants reported lower expectation for the female character to suggest the use of a condom when drinking across all partner types. The interaction revealed that the new and casual partner conditions responded similarly while drinking but the steady partner condition was significantly different in that participants expected the character to suggest a condom regardless of alcohol condition. The first regression equation revealed that impulsivity, though not alcohol use, was a significant factor in condom use self-efficacy. The second regression equation showed that impulsivity, alcohol use, and condom use self-efficacy all were significant predictors in participants? self-reported condom use. Consequences of alcohol intoxication and the risk in all partner types are imperative issues that young adults need to understand. The results suggest that increased harm reduction education and health education on disease risk with all types of partners are particularly needed in this population

    An Equation of State of a Carbon-Fibre Epoxy Composite under Shock Loading

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    An anisotropic equation of state (EOS) is proposed for the accurate extrapolation of high-pressure shock Hugoniot (anisotropic and isotropic) states to other thermodynamic (anisotropic and isotropic) states for a shocked carbon-fibre epoxy composite (CFC) of any symmetry. The proposed EOS, using a generalised decomposition of a stress tensor [Int. J. Plasticity \textbf{24}, 140 (2008)], represents a mathematical and physical generalisation of the Mie-Gr\"{u}neisen EOS for isotropic material and reduces to this equation in the limit of isotropy. Although a linear relation between the generalised anisotropic bulk shock velocity UsAU^{A}_{s} and particle velocity upu_{p} was adequate in the through-thickness orientation, damage softening process produces discontinuities both in value and slope in the UsAU^{A}_{s}-upu_{p} relation. Therefore, the two-wave structure (non-linear anisotropic and isotropic elastic waves) that accompanies damage softening process was proposed for describing CFC behaviour under shock loading. The linear relationship UsAU^{A}_{s}-upu_{p} over the range of measurements corresponding to non-linear anisotropic elastic wave shows a value of c0Ac^{A}_{0} (the intercept of the UsAU^{A}_{s}-upu_{p} curve) that is in the range between first and second generalised anisotropic bulk speed of sound [Eur. Phys. J. B \textbf{64}, 159 (2008)]. An analytical calculation showed that Hugoniot Stress Levels (HELs) in different directions for a CFC composite subject to the two-wave structure (non-linear anisotropic elastic and isotropic elastic waves) agree with experimental measurements at low and at high shock intensities. The results are presented, discussed and future studies are outlined.Comment: 12 pages, 9 figure

    Removing Orbital Debris with Lasers

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    Orbital debris in low Earth orbit (LEO) are now sufficiently dense that the use of LEO space is threatened by runaway collisional cascading. A problem predicted more than thirty years ago, the threat from debris larger than about 1 cm demands serious attention. A promising proposed solution uses a high power pulsed laser system on the Earth to make plasma jets on the objects, slowing them slightly, and causing them to re-enter and burn up in the atmosphere. In this paper, we reassess this approach in light of recent advances in low-cost, light-weight modular design for large mirrors, calculations of laser-induced orbit changes and in design of repetitive, multi-kilojoule lasers, that build on inertial fusion research. These advances now suggest that laser orbital debris removal (LODR) is the most cost-effective way to mitigate the debris problem. No other solutions have been proposed that address the whole problem of large and small debris. A LODR system will have multiple uses beyond debris removal. International cooperation will be essential for building and operating such a system.Comment: 37 pages, 15 figures, in preparation for submission to Advances in Space Researc

    Biopedagogies and Indigenous knowledge: examining sport for development and peace for urban Indigenous young women in Canada and Australia

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    This paper uses transnational postcolonial feminist participatory action research (TPFPAR) to examine two sport for development and peace (SDP) initiatives that focus on Indigenous young women residing in urban areas, one in Vancouver, Canada, and one in Perth, Australia. We examine how SDP programs that target urban Indigenous young women and girls reproduce the hegemony of neoliberalism by deploying biopedagogies of neoliberalism to \u27teach\u27 Indigenous young women certain education and employment skills that are deemed necessary to participate in competitive capitalism. We found that activities in both programs were designed to equip the Indigenous girls and young women with individual attributes that would enhance their chances of future success in arenas valued by neoliberal capitalism: Eurocentric employment, post-secondary education and healthy active living. These forms of \u27success\u27 fall within neoliberal logic, where the focus is on the individual being able to provide for oneself. However, the girls and young women we interviewed argued that their participation in the SDP programs would help them change racist and sexist stereotypes about their communities and thereby challenged negative stereotypes. Thus, it is possible that these programs, despite their predominant use of neoliberal logic and biopedagogies, may help to prepare the participants to more successfully negotiate Eurocentric institutions, and through this assist them participants in contributing to social change. Nevertheless, based on our findings, we argue that SDP programs led by Indigenous peoples that are fundamentally shaped by Indigenous voices, epistemologies, concerns and standpoints would provide better opportunities to shake SDP\u27s current biopedagogical foundation. We conclude by suggesting that a more radical approach to SDP, one that fosters Indigenous self-determination and attempts to disrupt dominant relations of power, could have difficulty in attracting the sort of corporate donors who currently play such important roles in the current SDP landscape

    Species-specific differences in the expression of the HNF1A, HNF1B and HNF4A genes

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    Background: The HNF1A, HNF1B and HNF4A genes are part of an autoregulatory network in mammalian pancreas, liver, kidney and gut. The layout of this network appears to be similar in rodents and humans, but inactivation of HNF1A, HNF1B or HNF4A genes in animal models cause divergent phenotypes to those seen in man. We hypothesised that some differences may arise from variation in the expression profile of alternatively processed isoforms between species. Methodology/Principal Findings: We measured the expression of the major isoforms of the HNF1A, HNF1B and HNF4A genes in human and rodent pancreas, islet, liver and kidney by isoform-specific quantitative real-time PCR and compared their expression by the comparative Ct (??Ct) method. We found major changes in the expression profiles of the HNF genes between humans and rodents. The principal difference lies in the expression of the HNF1A gene, which exists as three isoforms in man, but as a single isoform only in rodents. More subtle changes were to the balance of HNF1B and HNF4A isoforms between species; the repressor isoform HNF1B(C) comprised only 6% in human islets compared with 24–26% in rodents (p = 0.006) whereas HNF4A9 comprised 22% of HNF4A expression in human pancreas but only 11% in rodents (p = 0.001). Conclusions/Significance: The differences we note in the isoform-specific expression of the human and rodent HNF1A, HNF1B and HNF4A genes may impact on the absolute activity of these genes, and therefore on the activity of the pancreatic transcription factor network as a whole. We conclude that alterations to expression of HNF isoforms may underlie some of the phenotypic variation caused by mutations in these genes
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