189 research outputs found

    Research @ the Speed of Thought Executive Summary

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    An analysis of current research methods and technologies has revealed capability gaps in all of the required attributes. Amplification in the supply chain, disconnected processes, nonstandard data transactions, stove-piped communities, non-robust modeling techniques, misalignment of project milestone management, and significant data management overhead are but a few of the symptoms.https://corescholar.libraries.wright.edu/ms_lscm/1005/thumbnail.jp

    Evoking landscape practices through ethnographic fiction

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    Title from PDF of title page (University of Missouri--Columbia, viewed on September 10, 2013).The entire thesis text is included in the research.pdf file; the official abstract appears in the short.pdf file; a non-technical public abstract appears in the public.pdf file.Thesis advisor: Dr. Soren LarsenIncludes bibliographical references.M.A. University of Missouri--Columbia 2013.Dissertations, Academic -- University of Missouri--Columbia -- Geography."May 2013"Landscape has long been of central concern to cultural geography. Historically, the conceptualization of landscape rested on discursive binaries of subject-object, culture-nature, and self-other. Recent developments in cultural geography attempt to collapse these binaries through relational ontologies of landscape and a focus on the experience of landscape through practice. Yet, difficulties persist regarding the representation of landscapes, especially given that non-representational and phenomenological approaches have expanded landscape inquiry beyond the singular focus of representation while advocating experimental methodologies and new styles of writing Recent work in geography has taken up narrative as a way of pushing the boundaries of landscape writing and representation. I continue this work by exploring the conventions and techniques of ethnographic fiction to convey student encounters with the landscape during a three week field course in Southern Colorado. Despite its title, ethnographic fiction is actually a mode of textual representation in creative nonfiction that uses literary devices to interpret data from field work and produce factually accurate accounts concerning the social production of experience and meaning. Specifically, the text conveys meaning by synthesizing story, character, scene/setting, dialog, and a personally engaged author into a compelling narrative about cultural practice. Ethnographic fiction can be adapted to focus on the human experience of landscape through practice, which opens the possibility of exploring recent geographical treatments of landscape interaction in post-phenomenology and non-representational theory through narrative. When applied in an appropriate and critical manner, ethnographic fiction can be an effective genre for evoking the sensuous and ephemeral moments of engaging with landscape through direct experience as well as writing and reading

    Modelling Planck-scale Lorentz violation via analogue models

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    Astrophysical tests of Planck-suppressed Lorentz violations had been extensively studied in recent years and very stringent constraints have been obtained within the framework of effective field theory. There are however still some unresolved theoretical issues, in particular regarding the so called "naturalness problem" - which arises when postulating that Planck-suppressed Lorentz violations arise only from operators with mass dimension greater than four in the Lagrangian. In the work presented here we shall try to address this problem by looking at a condensed-matter analogue of the Lorentz violations considered in quantum gravity phenomenology. Specifically, we investigate the class of two-component BECs subject to laser-induced transitions between the two components, and we show that this model is an example for Lorentz invariance violation due to ultraviolet physics. We shall show that such a model can be considered to be an explicit example high-energy Lorentz violations where the ``naturalness problem'' does not arise.Comment: Talk given at the Fourth Meeting on Constrained Dynamics and Quantum Gravity (QG05), Cala Gonone (Sardinia, Italy) September 12-16, 200

    Hawking radiation without black hole entropy

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    In this Letter I point out that Hawking radiation is a purely kinematic effect that is generic to Lorentzian geometries. Hawking radiation arises for any test field on any Lorentzian geometry containing an event horizon regardless of whether or not the Lorentzian geometry satisfies the dynamical Einstein equations of general relativity. On the other hand, the classical laws of black hole mechanics are intrinsically linked to the Einstein equations of general relativity (or their perturbative extension into either semiclassical quantum gravity or string-inspired scenarios). In particular, the laws of black hole thermodynamics, and the identification of the entropy of a black hole with its area, are inextricably linked with the dynamical equations satisfied by the Lorentzian geometry: entropy is proportional to area (plus corrections) if and only if the dynamical equations are the Einstein equations (plus corrections). It is quite possible to have Hawking radiation occur in physical situations in which the laws of black hole mechanics do not apply, and in situations in which the notion of black hole entropy does not even make any sense. This observation has important implications for any derivation of black hole entropy that seeks to deduce black hole entropy from the Hawking radiation.Comment: Uses ReV_TeX 3.0; Five pages in two-column forma

    Conservation Laws in Doubly Special Relativity

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    Motivated by various theoretical arguments that the Planck energy (Ep - 10^19 GeV) - should herald departures from Lorentz invariance, and the possibility of testing these expectations in the not too distant future, two so-called "Doubly Special Relativity" theories have been suggested -- the first by Amelino-Camelia (DSR1) and the second by Smolin and Magueijo (DSR2). These theories contain two fundamental scales -- the speed of light and an energy usually taken to be Ep. The symmetry group is still the Lorentz group, but in both cases acting nonlinearly on the energy-momentum sector. Accordingly, since energy and momentum are no longer additive quantities, finding their values for composite systems (and hence finding the correct conservation laws) is a nontrivial matter. Ultimately it is these possible deviations from simple linearly realized relativistic kinematics that provide the most promising observational signal for empirically testing these models. Various investigations have narrowed the conservation laws down to two possibilities per DSR theory. We derive unique exact results for the energy-momentum of composite systems in both DSR1 and DSR2, and indicate the general strategy for arbitrary nonlinear realizations of the Lorentz group.Comment: V2: Extensive revisions: merged with gr-qc/0205093, new author added, references added, discussion amplified. 4 pages, revtex4; V3: Revised in response to referee comments; no physics changes; version to appear in Physical Review

    Lorentz violating kinematics: Threshold theorems

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    Recent tentative experimental indications, and the subsequent theoretical speculations, regarding possible violations of Lorentz invariance have attracted a vast amount of attention. An important technical issue that considerably complicates detailed calculations in any such scenario, is that once one violates Lorentz invariance the analysis of thresholds in both scattering and decay processes becomes extremely subtle, with many new and naively unexpected effects. In the current article we develop several extremely general threshold theorems that depend only on the existence of some energy momentum relation E(p), eschewing even assumptions of isotropy or monotonicity. We shall argue that there are physically interesting situations where such a level of generality is called for, and that existing (partial) results in the literature make unnecessary technical assumptions. Even in this most general of settings, we show that at threshold all final state particles move with the same 3-velocity, while initial state particles must have 3-velocities parallel/anti-parallel to the final state particles. In contrast the various 3-momenta can behave in a complicated and counter-intuitive manner.Comment: V1: 32 pages, 6 figures, 3 tables. V2: 5 references adde

    The Effect of Energy Patches on Substrate Utilization in Collegiate Cross-Country Runners

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    It is well established that an increased capacity of skeletal muscle to oxidize fatty acids can spare glycogen and delay the onset of fatigue in mild- to moderate-intensity exercise. The purpose of the following study was to examine the effect of LifeWave® energy patches on non-protein substrate utilization in Division-1 cross-country runners. To determine the effect of the patches subjects were pretested to establish baselines and randomly assigned to an experimental (EX) or placebo (PL) group. Twenty-two trained male (n = 11; mean ± SD, age = 21.1 ± 2.6years, height = 179.6 ± 4.2cm, body mass = 71.4 ± 7.4kg, VO2max = 72.6 ± 7.1mL•kg-1•min-1) and female (n = 11; mean ± SD, age = 21.5 ± 2.4years, height = 166.7 ± 5.7cm, body mass = 53.7 ± 3.2kg, VO2max = 63.6 ± 6.9mL•kg-1•min-1) cross-country runners volunteered to participate in the study. Dependent variables included maximal oxygen consumption (VO2max), rating of perceived exertion (RPE), respiratory exchange ratio (RER), maximum heart rate (HRmax), and time to exhaustion (TTE). Results indicated there were no significant differences between the EX and PL groups at posttesting for RPE, TTE, HRmax, or VO2max. RER was found to be significantly higher for the EX group compared to the PL group during stage 1 of the Bruce-protocol graded exercise test (p = 0.02). Based on the limited available research regarding LifeWave® energy patches effect on non-protein substrate utilization during aerobic exercise there appears to be no performance enhancing benefits

    Causal structure of acoustic spacetimes

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    The so-called ``analogue models of general relativity'' provide a number of specific physical systems, well outside the traditional realm of general relativity, that nevertheless are well-described by the differential geometry of curved spacetime. Specifically, the propagation of acoustic disturbances in moving fluids are described by ``effective metrics'' that carry with them notions of ``causal structure'' as determined by an exchange of sound signals. These acoustic causal structures serve as specific examples of what can be done in the presence of a Lorentzian metric without having recourse to the Einstein equations of general relativity. (After all, the underlying fluid mechanics is governed by the equations of traditional hydrodynamics, not by the Einstein equations.) In this article we take a careful look at what can be said about the causal structure of acoustic spacetimes, focusing on those containing sonic points or horizons, both with a view to seeing what is different from standard general relativity, and to seeing what the similarities might be.Comment: 51 pages, 39 figures (23 colour figures, colour used to convey physics information.) V2: Two references added, some additional discussion of maximal analytic extension, plus minor cosmetic change

    Investigation of biochemical biorefinery sizing and environmental sustainability impacts for conventional bale system and advanced uniform biomass logistics designs

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    The 2011 US Billion-Ton Update1 estimates that there are enough agricultural and forest resources to sustainably provide enough biomass to displace approximately 30% of the country’s current petroleum consumption. A portion of these resources are inaccessible at current cost targets with conventional feedstock supply systems because of their remoteness or low yields. Reliable analyses and projections of US biofuels production depend on assumptions about the supply system and biorefinery capacity, which, in turn, depend on economics, feedstock logistics, and sustainability. A cross-functional team has examined optimal combinations of advances in feedstock supply systems and biorefinery capacities with rigorous design information, improved crop yield and agronomic practices, and improved estimates of sustainable biomass availability. Biochemical-conversion-to-ethanol is analyzed for conventional bale-based system and advanced uniform-format feedstock supply system designs. The latter involves ‘pre-processing’ biomass into a higher-density, aerobically stable, easily transportable format that can supply large-scale biorefineries. Feedstock supply costs, logistics and processing costs are analyzed and compared, taking into account environmental sustainability metrics
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