Exploration of approaches to shock-wave simulations

This thesis covers research into a number of atomistic methods for the simulation of shock-waves, most importantly comparisons are drawn between the Hugoniostat method and non-equilibrium molecular dynamics (NEMD),with a view towards removing the limitations of pre-parametrised potentials in atomistic shock-wave studies and enable the capture of more complex phenomena and electronic properties.Simulations were performed on Argon and Silicate structures using standard potentials (the Lennard-Jones and van Beest, Kramer, van Santen (BKS) potentials for Argon and SiO2 respectively) and ab initio approaches.In this work, we present a reparametrisation of the BKS potential, which corrects some of the known flaws of the short-range modification of the BKS potential of Farrow and Probert. We also present algorithms and equations for developments and improvements to the Hugoniostat method including: convergence rate enhancements, methods for elimination of transient states and an automated system for the generation of Hugoniot curves.Further, we demonstrate the benefits of pseudo-equilibrium atomistic simulation to the study of shock-waves, with data obtained from these simulations including detailed local-structure analysis of shocked states of post-shockα-quartz and by applying known approaches of equilibrium molecular dynamics to the pseudo-equilibrium Hugoniostat method such as fluctuation formu-lae to calculate key system properties such as the Gr ̈uneisen parameter in theshocked state.We also attempt to determine the limitations of the Hugoniostat, how far we can stretch the paradigm of reduced system sizes without compromising the validity of the calculation of certain properties

The Soviet invasion of Afghanistan : trends and precedent in Soviet foreign policy.

http://archive.org/details/sovietinvasionof00wilkNAN

Supreme Court Voting Behavior - 2003 Term

The 2003 Term, for the second year, notes a liberal trend across a majority of the Tables of this Study. The voting behavior of individual Justices in 2003 was somewhat more stable this Term in that individual departures from past voting behaviors were less pronounced than in 2002. Nevertheless, the Study still demonstrates continuing instability in the voting behavior of individual Justices. This Term, statistically significant departures from past behavior by at least five Members of the Court are present on six Tables. This might suggest that the voting behavior of the Justices on these Tables is in transition, although the often-small statistical samples reported on many of these Tables also suggests caution in making (or relying upon) this inference. Bloc voting continues to control the outcome of a substantial number of the most controversial questions presented to the Court. But, as noted in the past few Studies, the voting power of conservative voting blocs seems to be losing steam. Justice O\u27Connor maintained her position as the Member of the Court most likely to cast the key swing-vote in closely divided opinions. The Study also demonstrates that Justice O\u27Connor\u27s voting behavior in state criminal cases has been a reliable indicator of the outcome of Majority Opinions in this category for a number of years. Her absence might alter decisional outcomes, not only in state criminal cases, but in the often-important cases decided by five-to-four votes of the Court

New experiments and a model-driven approach for interpreting Middle Stone Age Lithic Point Function using the Edge Damage Distribution Method

The Middle Stone Age (MSA) is associated with early evidence for symbolic material culture and complex technological innovations. However, one of the most visible aspects of MSA technologies are unretouched triangular stone points that appear in the archaeological record as early as 500,000 years ago in Africa and persist throughout the MSA. How these tools were being used and discarded across a changing Pleistocene landscape can provide insight into how MSA populations prioritized technological and foraging decisions. Creating inferential links between experimental and archaeological tool use helps to establish prehistoric tool function, but is complicated by the overlaying of post-depositional damage onto behaviorally worn tools. Taphonomic damage patterning can provide insight into site formation history, but may preclude behavioral interpretations of tool function. Here, multiple experimental processes that form edge damage on unretouched lithic points from taphonomic and behavioral processes are presented. These provide experimental distributions of wear on tool edges from known processes that are then quantitatively compared to the archaeological patterning of stone point edge damage from three MSA lithic assemblages--Kathu Pan 1, Pinnacle Point Cave 13B, and Die Kelders Cave 1. By using a model-fitting approach, the results presented here provide evidence for variable MSA behavioral strategies of stone point utilization on the landscape consistent with armature tips at KP1, and cutting tools at PP13B and DK1, as well as damage contributions from post-depositional sources across assemblages. This study provides a method with which landscape-scale questions of early modern human tool-use and site-use can be addressed

Athenaeus the Navigator

Copyright © The Society for the Promotion of Hellenic Studies 2008. Published version reproduced with the permission of the publisher.This study concerns navigation in a geographical sense and in the sense of the reader finding a way through a complex text with the help of points of reference. Recent studies in Athenaeus have suggested that he was a more sophisticated writer than the second-hand compiler of Hellenistic comment on classical Greek authors, which has been a dominant view. Building on these studies, this article argues that Athenaeus' approach to his history of ancient dining draws on traditional poetic links between the symposium and the sea, and expands such metaphors with a major interest in place and provenance, which also belongs to the literature of the symposium. Provenance at the same time evokes a theme of imperial thought, that Rome can attract to herself all the good things of the earth that are now under her sway. Good things include foods and the literary heritage of Greece now housed in imperial libraries. Athenaeus deploys themes of navigation ambiguously, to celebrate diversity and to warn against the dangers of luxury. Notorious examples of luxury are presented – the Sybarites and Capuans, for example – but there seem to be oblique warnings to Rome as well. Much clearer censure is reserved for the gastronomic poem of Archestratus of Gela, which surveys the best cities in which to eat certain fish. The Deipnosophists deplore the immorality of the poet and his radical rewriting of their key authors Homer and Plato, while at the same time quoting him extensively for the range of his reference to geography and fish. This commentary on Archestratus is a good example of the Deipnosophists' guidance to the reader, Roman or otherwise, who wishes to ‘navigate’ the complicated history of the Greek deipnon and symposium

Relativistic electron precipitation by EMIC waves: importance of nonlinear resonant effects

Relativistic electron losses in Earth's radiation belts are usually attributed to electron resonant scattering by electromagnetic waves. One of the most important wave mode for such scattering is the electromagnetic ion cyclotron (EMIC) mode. Within the quasi-linear diffusion framework, the cyclotron resonance of relativistic electrons with EMIC waves results in very fast electron precipitation to the atmosphere. However, wave intensities often exceed the threshold for nonlinear resonant interaction, and such intense EMIC waves have been shown to transport electrons away from the loss cone due to the force bunching effect. In this study we investigate if this transport can block electron precipitation. We combine test particle simulations, low-altitude ELFIN observations of EMIC-driven electron precipitation, and ground-based EMIC observations. Comparing simulations and observations, we show that, despite of the low pitch-angle electrons being transported away from the loss cone, the scattering at higher pitch angles results in the loss cone filling and electron precipitation

Yes, not now, or never: an analysis of reasons for refusing or accepting emergency department-based take-home naloxone.

OBJECTIVE: Take-home naloxone (THN) reduces deaths from opioid overdose. To increase THN distribution to at-risk emergency department (ED) patients, we explored reasons for patients' refusing or accepting THN. METHODS: In an urban teaching hospital ED, we identified high opioid overdose risk patients according to pre-specified criteria. We offered eligible patients THN and participation in researcher-administered surveys, which inquired about reasons to refuse or accept THN and about THN dispensing location preferences. We analyzed refusal and acceptance reasons in open-ended responses, grouped reasons into categories (absolute versus conditional refusals,) then searched for associations between patient characteristics and reasons. RESULTS: Of 247 patients offered THN, 193 (78.1%) provided reasons for their decision. Of those included, 69 (35.2%) were female, 91 (47.2%) were under age 40, 61 (31.6%) were homeless, 144 (74.6%) reported injection drug use (IDU), and 131 (67.9%) accepted THN. Of 62 patients refusing THN, 19 (30.7%) felt "not at risk" for overdose, while 28 (45.2%) gave conditional refusal reasons: "too sick," "in a rush," or preference to get THN elsewhere. Non-IDU was associated with stating "not at risk," while IDU, homelessness, and age under 40 were associated with conditional refusals. Among acceptances, 86 (65.7%) mentioned saving others as a reason. Most respondents preferred other dispensing locations beside the ED, whether or not they accepted ED THN. CONCLUSION: ED patients refusing THN felt "not at risk" for overdose or felt their ED visit was not the right time or place for THN. Most accepting THN wanted to save others

Automating Spacecraft Analysis: The Era of Ontological Modeling & Simulation

Verification by analysis is a predicted compliance of a design to imposed requirements. The levels of performance specified by performance requirements can be related to Technical Performance Measures (TPM) in a Model-Based Systems Engineering (MBSE) environment, but engineers performing verification by analysis are not commonly versed in professional Systems Engineering (SE) techniques or modeling languages such as SysML. As the formal application of Systems Engineering (SE) results in a diminution of time, effort, and money for large-scale projects, enabling technical engineers performing verification by analysis to contribute to MBSE improvements in the course of their daily work is financially incentivized. Ontologies applied to technical analysis methodologies are shown to improve the quality of verification by analysis activities while adhering to professional organization standards such as the International Council on Systems Engineering (INCOSE) SE Handbook and the National Aeronautics and Space Administration (NASA) standard 7009A: Standard for Models and Simulations

Plantar forefoot pressures in psoriatic arthritis-related dactylitis: an exploratory study

Dactylitis is a common feature of psoriatic arthritis (PsA); local physical trauma has been identified as a possible contributing factor. The aim of this study was to explore differences in forefoot plantar pressures in patients with PsA with and without dactylitis and compare to healthy controls. Thirty-six participants were recruited into three groups: group A PsA plus a history of dactylitis; group B PsA, no dactylitis; group C control participants. Forefoot plantar pressures were measured barefoot and in-shoe at the left second and fourth toes and corresponding metatarsophalangeal joints. Temporal and spatial parameters were measured and data from the foot impact scale for rheumatoid arthritis (FIS-RA), EQ5D and health assessment questionnaire (HAQ) were collected. Pressure time integral peak plantar pressure, and contact time barefoot and in-shoe were not significantly different between groups. Temporal and spatial parameters reported no significant differences between groups. ANOVA analysis and subsequent post hoc testing using Games-Howell test yielded significance in FIS-RA scores between both PsA groups versus controls, A p ≤ 0.0001 and PsA group B p < 0.0001 in the FIS-RA impairment and footwear domain, PsA group A p < 0.03 and PsA group B p ≤ 0.05 in the FIS-RA activity and participation domain compared to controls. This is the first exploratory study to investigate forefoot plantar pressures in patients with and without historical dactylitis in PsA. FIS-RA scores indicate PsA patients have significant limitations compared to controls, although a history of dactylitis does not appear to worsen patient reported outcomes