925 research outputs found
Baryon-Pion Couplings from Large-N QCD
We derive a set of consistency conditions for the pion-baryon coupling
constants in the large-N limit of QCD. The consistency conditions have a unique
solution which are precisely the values for the pion-baryon coupling constants
in the Skyrme model. We also prove that non-relativistic spin-flavor
symmetry (where is the number of light flavors) is a symmetry of the
baryon-pion couplings in the large-N limit of QCD. The symmetry breaking
corrections to the pion-baryon couplings vanish to first order in .
Consistency conditions for other couplings, such as the magnetic moments are
also derived.Comment: (12 pages, 2 figs, uses harvmac and uufiles), UCSD/PTH 93-1
Liver Transplantation With Incidental Gallbladder Carcinoma in the Recipient Hepatectomy
Gallbladder carcinoma(GBCA) is the most common malignancy of the biliary tract1 and is often
found seredipitiously after cholecystectomy. We report the first two cases of incidental GBCA in the
native gallbladder of two liver transplant recipients. Both patients are 2.5 years following uneventful
orthotopiic liver transplantation(OLTx) with no evidence of recurrent disease. Pathology of both
recipients was early and favorable. Neither patient received any further therapy. Given the incidence
of GBCA and the evolution of OLTx we would anticipate this finding to be more prevalent
Survey under-coverage of top incomes and estimation of inequality: what is the role of the UK’s SPI adjustment?
Survey under-coverage of top incomes leads to bias in survey-based estimates of overall income inequality. Using income tax record data in combination with survey data is a potential approach to address the problem; we consider here the UK’s pioneering ‘SPI adjustment’ method that implements this idea. Since 1992, the principal income distribution series (reported annually in Households Below Average Income) has been based on household survey data in which the incomes of a small number of ‘very rich’ individuals are adjusted using information from ‘very rich’ individuals in personal income tax return data. We explain what the procedure involves, reveal the extent to which it addresses survey under-coverage of top incomes, and show how it affects estimates of overall income inequality. More generally, we assess whether the SPI adjustment is fit for purpose and consider whether variants of it could be employed by other countries
Alternatives for Navigating Small Unmanned Air Vehicles without GPS
Considering the increased reliance on GPS navigation for the Army’s Unmanned Aircraft Systems, adversaries have invested in capabilities to deny our systems access to genuine GPS signals. Although significant effort has been put forth in the areas of anti-jamming and anti-spoofing in GPS receivers, a need for alternative navigation methods in a GPS denied environment has grown in importance. This report outlines the recommendation and analysis completed for Mr. Lars Ericsson of the Army Project Manager Unmanned Aircraft Systems (PM-UAS).  The report includes background research in the domain space, comprehensive stakeholder analysis, derived system requirements and functional requirements, ending with alternative generation, value scoring, costing, and provided findings for a recommended alternative for future consideration.Â
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