652 research outputs found
Examining the Impact of Quality Assurance Manning Practices in USAF Aircraft Maintenance Units
The purpose of this research was to examine the impact that current USAF Quality Assurance (QA) manning practices has on key aircraft wing- and unit-level metrics. Interviews and surveys culminated in development of a QA Manning Effectiveness Matrix. We then used the matrix to calculate historical QA manning effectiveness at 16 ACC bases. Effectiveness scores were regressed with associated historical data for 26 metrics derived from a Delphi survey. Nine metrics were deemed statistically significant, including break rates, cannibalization rates, flying schedule effectiveness rates, key task list pass rates, maintenance scheduling effectiveness rates, quality verification inspection pass rates, repeat rates, dropped objects counts and safety/technical violations counts. An example benefit cost analysis for changes in QA manning effectiveness was performed, using reasonable cost values. The results present compelling evidence for maintenance managers to carefully weigh decisions to leave QA manning slots empty, or to assign personnel possessing other than authorized credentials. Maintenance managers can use this tool to help determine mitigating strategies for improving unit performance with respect to the nine metrics
Can a Lattice String Have a Vanishing Cosmological Constant?
We prove that a class of one-loop partition functions found by Dienes, giving
rise to a vanishing cosmological constant to one-loop, cannot be realized by a
consistent lattice string. The construction of non-supersymmetric string with a
vanishing cosmological constant therefore remains as elusive as ever. We also
discuss a new test that any one-loop partition function for a lattice string
must satisfy.Comment: 14 page
Regional Transportation and Land Use Decision Making in Metropolitan Regions: Findings from Four Case Studies
Throughout the United States, metropolitan regions face increasingly complex issues related to transportation and land use. The diffuse nature of decision making creates a need to better coordinate land use and transportation to address issues such as: congestion, infrastructure costs, and greenhouse gas emissions. Key players in this decision making are regional metropolitan planning organizations (MPOs) with transportation planning authority, regional planning responsibilities, and in some cases regional land use planning authority. The goal of this study was to describe and assess efforts by regional agencies to coordinate land use and transportation. Policies and processes in four key topic areas were examined: 1) Governance: formal and informal decision making approaches; 2) Coordination: strategies used to coordinate land use and transportation; 3) Growth Centers: policies to encourage development in higher density centers; and 4) Transportation Improvement Program (TIP): policies to incorporate smart growth criteria in TIP funding decisions
Recommended from our members
Using administrative data to monitor racial/ethnic disparities and disproportionality within child welfare agencies: process and preliminary outcomes
Child welfare administrative data are increasingly used to identify racial/ethnic disproportionality and disparities at various levels of aggregation. However, child welfare agencies typically face challenges in harnessing administrative data to examine racial/ethnic disproportionality and disparities at meaningful levels of analysis due to limited resources and/or tools for reporting. This article describes the process through which a multi-state workgroup designed and developed management reports to monitor racial/ethnic disparities and disproportionality using a web-based child welfare administrative data reporting system. The article provides an overview of the process, outcome, and challenges of the group’s work with the goal of offering a starting point for discussion to others who may be seeking to monitor racial/ethnic disparities and disproportionality, regardless of their reporting system
Oncolog, Volume 37, Issue 02, April-June 1992
The primacy of patient welfare Potential doubling time of tumors may be the key to accurate prognosis, appropriate treatment Cognitive deficits in survivors of childhood cancershttps://openworks.mdanderson.org/oncolog/1038/thumbnail.jp
Twisted brane charges for non-simply connected groups
The charges of the twisted branes for strings on the group manifold SU(n)/Z_d
are determined. To this end we derive explicit (and remarkably simple) formulae
for the relevant NIM-rep coefficients. The charge groups of the twisted and
untwisted branes are compared and found to agree for the cases we consider.Comment: 30 page
Recommended from our members
Conceptual Design of a Very High Temperature Pebble-Bed Reactor
Efficient electricity and hydrogen production distinguish the Very High Temperature Reactor as the leading Generation IV advanced concept. This graphite-moderated, helium-cooled reactor achieves a requisite high outlet temperature while retaining the passive safety and proliferation resistance required of Generation IV designs. Furthermore, a recirculating pebble-bed VHTR can operate with minimal excess reactivity to yield improved fuel economy and superior resistance to ingress events. Using the PEBBED code developed at the INEEL, conceptual designs of 300 megawatt and 600 megawatt (thermal) Very High Temperature Pebble-Bed Reactors have been developed. The fuel requirements of these compare favorably to the South African PBMR. Passive safety is confirmed with the MELCOR accident analysis code
Ozone loss derived from balloon-borne tracer measurements and the SLIMCAT CTM
Balloon-borne measurements of CFC-11 (on flights of the DIRAC in situ gas chromatograph and the DESCARTES grab sampler), ClO and O3 were made during the 1999/2000 winter as part of the SOLVE-THESEO 2000 campaign. Here we present the CFC-11 data from nine flights and compare them first with data from other instruments which flew during the campaign and then with the vertical distributions calculated by the SLIMCAT 3-D CTM. We calculate ozone loss inside the Arctic vortex between late January and early March using the relation between CFC-11 and O3 measured on the flights, the peak ozone loss (1200 ppbv) occurs in the 440–470 K region in early March in reasonable agreement with other published empirical estimates. There is also a good agreement between ozone losses derived from three independent balloon tracer data sets used here. The magnitude and vertical distribution of the loss derived from the measurements is in good agreement with the loss calculated from SLIMCAT over Kiruna for the same days
Association of Aortic Stiffness With Biomarkers of Neuroinflammation, Synaptic Dysfunction, and Neurodegeneration
OBJECTIVES: To test the hypothesis that increased aortic stiffening is associated with greater cerebrospinal fluid (CSF) evidence of core Alzheimer's disease pathology (Aβ, phosphorylated tau (p-tau)), neurodegeneration (total tau (t-tau)), synaptic dysfunction (neurogranin), neuroaxonal injury (neurofilament light (NFL)), and neuroinflammation (YKL-40, sTREM2), we analyzed pulse wave velocity (PWV) data and CSF data among older adults. METHODS: Participants free of stroke and dementia from the Vanderbilt Memory and Aging Project, an observational community-based study, underwent cardiac magnetic resonance to assess aortic pulse wave velocity (PWV, m/sec) and lumbar puncture to obtain CSF. Linear regressions related aortic PWV to CSF Aβ, p-tau, t-tau, neurogranin, NFL, YKL-40, and sTREM2 concentrations adjusting for age, race/ethnicity, education, apolipoprotein (APOE) ε4 status, Framingham Stroke Risk Profile, and cognitive diagnosis. Models were repeated testing PWV interactions with age, diagnosis, APOE-ε4, and hypertension on each biomarker. RESULTS: 146 participants were examined (72±6 years). Aortic PWV interacted with age on p-tau (β=0.31, p=0.04), t-tau, (β=2.67, p=0.05), neurogranin (β=0.94, p=0.04), and sTREM2 (β=20.4, p=0.05). Among participants over age 73 years, higher aortic PWV related to higher p-tau (β=2.4, p=0.03), t-tau (β=19.3, p=0.05), neurogranin (β=8.4, p=0.01), and YKL-40 concentrations (β=7880, p=0.005). Aortic PWV had modest interactions with diagnosis on neurogranin (β=-10.76, p=0.03) and hypertension status on YKL-40 (β=-18020, p<0.001). CONCLUSIONS: Among our oldest participants, age 74 years and older, greater aortic stiffening is associated with in vivo biomarker evidence of neuroinflammation, tau phosphorylation, synaptic dysfunction, and neurodegeneration, but not amyloidosis. Central arterial stiffening may lead to cumulative cerebral microcirculatory damage and blood flow delivery to tissue, resulting in neuroinflammation and neurodegeneration in more advanced age
- …