16,332 research outputs found
Early exposure to environmental toxin contributes to neuronal vulnerability and axonal pathology in a model of familial ALS
Adult onset amyotrophic lateral sclerosis (ALS) arises due to progressive and irreversible functional deficits to the central nervous system, specifically the loss of motor neurons. Sporadic ALS causality is not well understood, but is almost certainly of multifactorial origin involving a combination of genetic and environmental factors. The discovery of endemic ALS in the native Chamorro population of Guam during the 1950s and the co-occurrence of parkinsonism and dementia in some patients led to searches for an environmental toxins that could be responsible. In the present paper, we report that an environmental neurotoxin enhances mutant superoxide dismutase (SOD)-induced spinal motor neuron death and pathology and induces motor axon abnormalities. These results cumulatively confirm earlier findings that exposure to an environmental toxin is sufficient to produce the disease phenotype and indicate a role for gene-environment interaction in some forms of the disease
Computer-Supported Elicitation of Curatorial Intent
I elaborate a programme of research to develop and test mechanisms for eliciting the curatorial intent of individuals related to digital objects transferred to repositories
Digital Forensics Meets the Archivist (And They Seem to Like Each Other)
Materials with archival value are now predominantly born digital. Archivists have unprecedented opportunities to acquire and preserve traces of human and associated machine activity. Seizing these opportunities will require archivists to extract digital materials from their storage or transfer media in ways that reflect the metadata and ensure the integrity of the materials. They must also support and mediate appropriate access: allowing users to make sense of materials and their context, while also preventing inadvertent disclosure of sensitive data
Augustine vs. Archisynagogus: Competing Modes of Christian Instruction in the Benediktbeuern Ludus de nativitate
This article situates the Archisynagogus episode of the Benediktbeuern Ludus de nativitate within the tradition of medieval Christian-Jewish debate literature. This genre typically presents doctrinal instruction through the confrontation of two perspectives and the ultimate refutation of Jewish arguments, yet, in the Christmas Play, the medium of debate is itself rejected along with all rational approaches to understanding Christian mystery. As part of its anti-scholastic focus, the play instead promotes an Augustinian concept of inspired learning where belief and visual res (looking on in faith) are the proper approaches to enlightenment rather than logical arguments. In this, the Ludus ultimately privileges the viewing of religious drama as the ideal means of attaining Christian truth
The ecology of root disease fungi in Missouri forests
Dissertation supervisor: Dr. Rose-Marie Muzika.Includes vita.Root disease fungi have important ecological and economic effects on tree species around the world. A better understanding of their basic ecological significance -- how they modify the growth and development of the tree communities of which they are a part -- will help us better understand how to manage them. This project looked at basic aspects of the Missouri distribution and infection prevalence of two important root disease fungal genera, Heterobasidion and Armillaria. Among other things, the study determined that the pine-infecting Heterobasidion is widely distributed in the Missouri Ozarks, which should factor into the planning process connected with shortleaf pine restoration efforts throughout the region. The study also looked at Armillaria gallica, which is very widespread in Missouri soils but tends to infect only hardwood trees that are already under stress. In plots in central Missouri, A. gallica was found more widely in younger, denser stands of trees than in more mature stands, which is likely connected to the existence of other stress factors in those dense stands, such as competition from other trees for light and water. Seven years after clearcutting in the Ozarks, all three species of Armillaria found in Missouri had infected the majority of stumps onsite, including those that were still living and producing new sprouts. However, some stumps were more vigorous than others, and just because a stump was infected did not mean that the infection was advancing to kill it. This study contributed to a better understanding of how root pathogens in changing Missouri landscapes are influenced by land management in terms of both their distribution and their potential for having an impact on the next generation of forests.Includes bibliographical references
Design and testing of low sonic boom configurations and an oblique all-wing supersonic transport
From December 1991 to June 1992, applied aerodynamic research support was given to the team working on Low Sonic Boom configurations in the RAC branch at NASA Ames Research Center. This team developed two different configurations: a conventional wing-tail and a canard wing, in an effort to reduce the overpressure of shock waves and the accompanying noise which are projected to the ground from supersonic civil transport aircraft. A generic description of this sensitive technology is given
Transient x-ray absorption spectroscopy of hydrated halogen atom
Time-resolved x-ray absorption spectroscopy monitors the transient species
generated by one-photon detachment of an electron from aqueous bromide.
Hydrated bromine atoms with a lifetime of ca. 17 ns were observed, nearly half
of which react with excess Br- to form Br2-. The K-edge spectra of the Br atom
and Br2- anion exhibit distinctive resonant transitions that are absent for the
Br- precursor. The absorption spectra indicate that the solvent shell around a
Br0 atom is defined primarily by hydrophobic interactions, in agreement with a
Monte Carlo simulation of the solvent structure.Comment: 6 pages, 4 figures + supplement, will be submitted to PR
Design and testing of an oblique all-wing supersonic transport
This report describes the preliminary design of an Oblique All-Wing (OAW) supersonic transport and a corresponding wind-tunnel model that was tested in the NASA Ames 9- by 7-Foot supersonic wind tunnel. The main goal was the determination of the cruise performance (lift/drag ratio) of a realistically configured OAW. To achieve an acceptable level of realism, it was necessary to consider many issues of design practicality such as the need for a viable propulsion system, adequate control surfaces, landing gear, provisions for 450 passengers, and fuel to fly 5,000 nautical miles. The aircraft had to be stable, structurally sound, and needed to fit into airports across the world. Support was directed primarily towards integration of the propulsion system, however, there were notable contributions to many aspects of the configuration design, wind tunnel model, and wind tunnel test
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