14,339 research outputs found
Portable, high intensity isotopic neutron source provides increased experimental accuracy
Small portable, high intensity isotopic neutron source combines twelve curium-americium beryllium sources. This high intensity of neutrons, with a flux which slowly decreases at a known rate, provides for increased experimental accuracy
Apparatus for fabrication of americium- beryllium neutron sources prevents capsule contamination
Modified gloved enclosure is used to fill a capsule with a mixture of americium and beryllium radioactive powders to seal weld the opening, and to test it for leaks. It contains a horizontal partition, vortex mixer, mounting press, welder, test vessel, and radiation shielding to prevent surface contamination
Survey of Human Mitochondrial Diseases Using New Genomic/Proteomic Tools
BACKGROUND. We have constructed Bayesian prior-based, amino-acid sequence profiles for the complete yeast mitochondrial proteome and used them to develop methods for identifying and characterizing the context of protein mutations that give rise to human mitochondrial diseases. (Bayesian priors are conditional probabilities that allow the estimation of the likelihood of an event - such as an amino-acid substitution - on the basis of prior occurrences of similar events.) Because these profiles can assemble sets of taxonomically very diverse homologs, they enable identification of the structurally and/or functionally most critical sites in the proteins on the basis of the degree of sequence conservation. These profiles can also find distant homologs with determined three-dimensional structures that aid in the interpretation of effects of missense mutations. RESULTS. This survey reports such an analysis for 15 missense mutations one insertion and three deletions involved in Leber's hereditary optic neuropathy, Leigh syndrome, mitochondrial neurogastrointestinal encephalomyopathy, Mohr-Tranebjaerg syndrome, iron-storage disorders related to Friedreich's ataxia, and hereditary spastic paraplegia. We present structural correlations for seven of the mutations. CONCLUSIONS. Of the 19 mutations analyzed, 14 involved changes in very highly conserved parts of the affected proteins. Five out of seven structural correlations provided reasonable explanations for the malfunctions. As additional genetic and structural data become available, this methodology can be extended. It has the potential for assisting in identifying new disease-related genes. Furthermore, profiles with structural homologs can generate mechanistic hypotheses concerning the underlying biochemical processes - and why they break down as a result of the mutations.United States Department of Energy (DE-FG02-98ER62558); National Science Foundation (DBI-9807993
Investigation of continental drift, phase 1 effort Progress report, 1 Apr. - 30 Sep. 1968
Feasibility of using ultrashort pulse laser ranging and independent clock radio interferometry distance measurement methods to test for existence of continental drif
Service Delivery in Rural Municipalities: Privatize, Cooperate, or Go It Alone?
Choices in production and contracting arrangements for a wide range of services were studied using data from approximately 1,000 small, mostly rural municipalities from Illinois, New Hampshire and Wisconsin. Results suggest the use of both for-profit contractors and cooperative agreements with other governments correlate negatively with population. Small municipalities are less likely to use competitive bidding processes, compare costs between production options, or report that privatization produces savings. Median income, rural geography, and ideology show statistically-significant associations with contracting choices. Respondents generally consider themselves ―satisfied‖ with services provided by contract, although satisfaction levels are lower than those associated with self-provision. Satisfaction associated with services provided by other governments is lower than satisfaction with services provided by private contractors, suggesting no tradeoff in service quality directly attributable to ―for-profit‖ contractors.privatization, municipal services, cooperation, Community/Rural/Urban Development, Public Economics,
Lateral palatal flap approach to the nasopharynx and parapharyngeal space for transoral robotic surgery: a cadaveric study
The da Vinci surgical robot has been used for minimally invasive surgery of the head and neck region including resection of tumors in the nasopharynx. Access to and vision of the nasopharynx with the robot are difficult. A pure transoral approach and midline palatal split approach have been described. The disadvantage of these approaches is the limited lateral access to the parapharyngeal space. The objective of this study was to investigate the feasibility of accessing the nasopharynx and parapharyngeal space with a lateral palatal flap. Two complete nasopharyngectomies with resection of the parapharyngeal space and exposure of the internal carotid artery and branches of the mandibular nerves were performed on two fresh cadavers with the da Vinci surgical robot. The set up of the robot, the surgical procedure of elevating the lateral palatal flap, and robotic resection of the nasopharynx and parapharyngeal space are described. © 2012 The Author(s).published_or_final_versionSpringer Open Choice, 28 May 201
Shifting Focus: Connecting Public Space with Everday Life
If public art is to emerge beyond its present constraints it must include a new approach by adventuresome artists and public art agencies to include an embrace of the ubiquitous unmapped, and un-claimed territories which possess permeable borders found in our vulnerable communities and peripheral public spaces which are typically rooted on the edge of artistic heritage. The history of public art has shifted focus; it’s no longer about monuments or large scale projects with big budgets but about footnotes. The big events have been commemorated, now the little ones wait to shape our understanding of public space design. This new conception of public space design fills in spaces where stories haven’t been told, it’s more accessible to our daily uses and about anonymous people and communities who worked hard to build our communities from within. Moreover, it is the theoretical implications of how this is articulated in the context of communities in constant flux, subject to the effects of social dislocations, economic decay and misguided strategies for designing and engaging public space for an overly stimulated and distracted public.
More importantly, and perhaps the more interesting question could become, and the subsequent discussion of a presumed predictability must include the recognition that the future of public art is dependent on an overdue reexamination, and redefinition of meaning of the clichéd and over used term “site responsiveness” as the empirical definition of what constitutes “good public art.
Lamb Shift of 3P and 4P states and the determination of
The fine structure interval of P states in hydrogenlike systems can be
determined theoretically with high precision, because the energy levels of P
states are only slightly influenced by the structure of the nucleus. Therefore
a measurement of the fine structure may serve as an excellent test of QED in
bound systems or alternatively as a means of determining the fine structure
constant with very high precision. In this paper an improved analytic
calculation of higher-order binding corrections to the one-loop self energy of
3P and 4P states in hydrogen-like systems with low nuclear charge number is
presented. A comparison of the analytic results to the extrapolated numerical
data for high ions serves as an independent test of the analytic
evaluation. New theoretical values for the Lamb shift of the P states and for
the fine structure splittings are given.Comment: 33 pages, LaTeX, 4 tables, 4 figure
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