Odd-primary homotopy exponents of compact simple Lie groups

We note that a recent result of the second author yields upper bounds for odd-primary homotopy exponents of compact simple Lie groups which are often quite close to the lower bounds obtained from v_1-periodic homotopy theory.Comment: This is the version published by Geometry & Topology Monographs on 22 February 200

Needle Exchange Programs to Prevent Hepatitis C Virus Infection in People Who Inject Drugs in Rural Appalachia

The recent opioid epidemic in the rural Appalachian region of the United States has fueled an exponential increase in hepatitis C virus (HCV) infection among People Who Inject Drugs (PWID). Needle exchange programs (NEP), which provide clean needles in exchange for used needles, can reduce the incidence of HCV among PWIDs. However, the empirical evidence examining NEP effectiveness in the prevention of HCV in this population is mixed, only describes studies conducted in urban areas, and does not address the unique challenges associated with implementing NEPs in rural areas. Furthermore, no studies have examined barriers to using clean needles obtained from NEPs in rural settings. Therefore, there is a critical need to understand the unique context and programmatic challenges of rural NEPs to design and implement successful programs to reduce HCV transmission in this underserved population. The objective of this dissertation was to improve empirical evidence related to NEP efficacy, examine programmatic challenges encountered by rural NEPs, and identify clean needle use barriers unique to rural areas. The rationale underlying this research is that improved understanding of operational and clean needle use barriers will promote successful implementation of NEPs in rural areas. In the first study, a systematic review with meta-analysis was conducted to update the empirical evidence related to NEP prevention of HCV in PWIDs. Findings from this study revealed that the overall impact of NEPs on HCV prevention remains unclear and is complicated by significant heterogeneity between studies. Furthermore, no rural studies were identified in the review. Standardization of population characteristics, intervention components, empirical comparisons, and outcome assessments is suggested to reduce heterogeneity and clarify the empirical contribution of NEPs to HCV prevention. In the second study, a qualitative case study design was employed to examine barriers and facilitators to NEP implementation, ongoing operations, and future sustainability. Structured interviews with program directors, law enforcement leaders and personnel, and NEP attendees revealed common barriers and facilitators to program operations. Findings from this study indicated that despite broad community support, growing volumes, funding shortages, and the federal government\u27s prohibition on the use of funds to purchase needles threatened program operations. Furthermore, paraphernalia laws created a legal conundrum in the form of criminal sanctions for the possession of needles, which may inadvertently promote needle sharing and disease transmission. In the third study, a mixed methods survey of PWIDs attending two rural, Appalachian programs regarding barriers to using clean needles obtained from the exchange for every injection was employed. Findings from this study revealed that fear of arrest and problems with obtaining clean needles from pharmacies were the most commonly endorsed barriers to clean needle use. The results of this dissertation suggest that NEPs opened in rural Central Appalachia in response to an opioid and heroin epidemic have enjoyed robust community support and are viewed as an important infectious diseases prevention mechanism by PWIDs. However, the overall impact of NEPs on preventing HCV in rural PWIDs is unclear and, similar to urban areas of the United States, may be blunted by legal structural influences (i.e. paraphernalia laws) that impact policing behaviors. Future studies should explore the factors associated with these structural barriers that may prevent the ability of rural PWIDs to use a clean needle during every injection, which, in turn, may minimize the overall efficacy of these programs on HCV prevention. Further research is also needed on the feasibility of implementing the addition of opiate replacement therapy (i.e., methadone, buprenorphine) with NEPs given the strong protective effect on HCV seroconversion observed in several European studies implementing this combined approach consistently over time

Cosmic Strings, Zero Modes and SUSY breaking in Nonabelian N=1 Gauge Theories

We investigate the microphysics of cosmic strings in Nonabelian gauge theories with N=1 supersymmetry. We give the vortex solutions in a specific example and demonstrate that fermionic superconductivity arises because of the couplings and interactions dictated by supersymmetry. We then use supersymmetry transformations to obtain the relevant fermionic zero modes and investigate the role of soft supersymmetry breaking on the existence and properties of the superconducting strings.Comment: 12 pages, RevTex, submitted to Phys. Rev.

The connective K-theory of the Eilenberg-MacLane space K(Z/p,2)

We compute ku^*(K(Z/p,2)) and ku_*(K(Z/p,2)), the connective KU-cohomology and connective KU-homology groups of the mod-p Eilenberg-MacLane space K(Z/p,2), using the Adams spectral sequence. We obtain a striking interaction between h_0-extensions and exotic extensions. The mod-p connective KU-cohomology groups, computed elsewhere, are needed in order to establish higher differentials and exotic extensions in the integral groups

An Archaeological Survey and Assessment of the Proposed North Mecklenburg Water Treatment Plant Site Near Huntersville, Mecklenburg County, North Carolina

Technical Report No. 21, Research Laboratories of Archaeology, University of North Carolina at Chapel Hill. Reports in this series present the findings of archaeological surveys and test excavations completed by the RLA between 1983 and present

Fermionic Zero Modes of Supergravity Cosmic Strings

Recent developments in string theory suggest that cosmic strings could be formed at the end of brane inflation. Supergravity provides a realistic model to study the properties of strings arising in brane inflation. Whilst the properties of cosmic strings in flat space-time have been extensively studied there are significant complications in the presence of gravity. We study the effects of gravitation on cosmic strings arising in supergravity. Fermion zero modes are a common feature of cosmic strings, and generically occur in supersymmetric models. The corresponding massless currents can give rise to stable string loops (vortons). The vorton density in our universe is strongly constrained, allowing many theories with cosmic strings to be ruled out. We investigate the existence of fermion zero modes on cosmic strings in supergravity theories. A general index theorem for the number of zero modes is derived. We show that by including the gravitino, some (but not all) zero modes disappear. This weakens the constraints on cosmic string models. In particular, winding number one cosmic D-strings in models of brane inflation are not subject to vorton constraints. We also discuss the effects of supersymmetry breaking on cosmic D-strings.Comment: 33 page

Multidirectional photodiode array for the measurement of solar radiances

February, 1980.Includes bibliographical references.Sponsored by grant by the Eppley Laboratory, Inc.Sponsored by the National Science Foundation ATM 78-12631

Oxygen Compatibility of Brass-Filled PTFE Compared to Commonly Used Fluorinated Polymers for Oxygen Systems

Safe and reliable seal materials for high-pressure oxygen systems sometimes appear to be extinct species when sought out by oxygen systems designers. Materials that seal well are easy to find, but these materials are typically incompatible with oxygen, especially in cryogenic liquid form. This incompatibility can result in seals that leak, or much worse, seals that easily ignite and burn during use. Materials that are compatible with oxygen are easy to find, such as the long list of compatible metals, but these metallic materials are limiting as seal materials. A material that seals well and is oxygen compatible has been the big game in the designer's safari. Scientists at the Materials Combustion Research Facility (MCRF), part of NASA/Marshall Space Flight Center (MSFC), are constantly searching for better materials and processes to improve the safety of oxygen systems. One focus of this effort is improving the characteristics of polymers used in the presence of an oxygen enriched environment. Very few systems can be built which contain no polymeric materials; therefore, materials which have good impact resistance, low heat of combustion, high auto-ignition temperature and that maintain good mechanical properties are essential. The scientists and engineers at the Materials Combustion Research Facility, in cooperation with seal suppliers, are currently testing a new formulation of polytetrafluoroethylene (PTFE) with Brass filler. This Brass-filled PTFE is showing great promise as a seal and seat material for high pressure oxygen systems. Early research has demonstrated very encouraging results, which could rank this material as one of the best fluorinated polymers ever tested. This paper will compare the data obtained for Brass-filled PTFE with other fluorinated polymers, such as TFE-Teflon (PTFE) , Kel-F 81, Viton A, Viton A-500, Fluorel , and Algoflon . A similar metal filled fluorinated polymer, Salox-M , was tested in comparison to Brass-filled PTFE to demonstrate the importance of the metal chosen and relative percentage of filler. General conclusions on the oxygen compatibility of this formulation are drawn, with an emphasis on comparing and contrasting the materials performance to the performance of the current state-of-the-art oxygen compatible polymers