7,075 research outputs found
Global Existence Results and Uniqueness for Dislocation Equations
We are interested in nonlocal Eikonal Equations arising in the study of the
dynamics of dislocations lines in crystals. For these nonlocal but also non
monotone equations, only the existence and uniqueness of Lipschitz and
local-in-time solutions were available in some particular cases. In this paper,
we propose a definition of weak solutions for which we are able to prove the
existence for all time. Then we discuss the uniqueness of such solutions in
several situations, both in the monotone and non monotone case
Potential use of the bioreactor to determine effects of microgravity and other environmental parameters on growth of hybridoma cells
It is argued that the bioreactor being developed at NASA will allow researchers to determine the optimal conditions (e.g., pH, O sub 2, CO sub 2, nutrients) for growth of hybridoma cells, and to determine whether cell growth and antibody production are enhanced in the microgravity of space
A Study of Wage Contour Determinants For Northern Minnesota
This paper reports the findings of a study designed to profile wages and employment in northern Minnesota. Because of differences in the structure of the local economy and differences in the composition of the labor force, we hypothesized that studies done for other regions as well as national studies might produce misleading information if applied to northern Minnesota. The study is based on responses to 1400 mail surveys distributed in 1983 in four cities in northern Minnesota: Bemidji, Brainerd, Fergus Falls, and Grand Rapids. We found some surprising differences between the workforces in the four cities. Our overall impression was of an older, stable workforce characterized by long-term attachment to geographical location and occupation. The workforce is heavily concentrated in the service sector and has a smaller number of workers in manufacturing than the national figures would predict. Earnings in the region are somewhat below the nation\u27s norm. Finally, the region\u27s workforce is traditional in the sense that it reflects historical male/ female wage differentials and tends toward occupational segregation by sex
Property Tax Equity: A Study of Bemidji, Minnesota
The paper seeks to evaluate the equity of property tax assessments in a rural northern Minnesota area. Criteria of both vertical and horizontal equity were examined in terms of the ability to pay and benefits measures of the intra-decile relationships. In addition, other variables affecting intra-decile horizontal equity such as age and lakeshore location were considered. The data upon which the results were based were drawn from random sampling of 1000 households in the R-31 school district at Bemidji, Beltrami County, Minnesota. The sample represented 20 percent of all such households. A total of 216 households responded to a questionnaire which asked for adjusted gross income. tax assessments, number of children enrolled in R-31 schools, property tax credits, age of taxpayers, and whether the property was lakeshore or not. The study concludes that the property tax assessments in Bemidji violate both vertical and horizontal standards for equity whether measured in terms of the ability to pay or of benefits. It also appears that intra-decile horizontal equity is violated in terms of lakeshore versus non-lakeshore assessments. Finally, older people in the lower income deciles are taxed more heavily than average
Quantum-state input-output relations for absorbing cavities
The quantized electromagnetic field inside and outside an absorbing high-
cavity is studied, with special emphasis on the absorption losses in the
coupling mirror and their influence on the outgoing field. Generalized operator
input-output relations are derived, which are used to calculate the Wigner
function of the outgoing field. To illustrate the theory, the preparation of
the outgoing field in a Schr\"{o}dinger cat-like state is discussed.Comment: 12 pages, 5 eps figure
Molecular epidemiologic investigations of Mycoplasma gallisepticum conjunctivitis in songbirds by random amplified polymorphic DNA analyses.
An ongoing outbreak of conjunctivitis in free-ranging house finches (Carpodacus mexicanus) began in 1994 in the eastern United States. Bacterial organisms identified as Mycoplasma gallisepticum (MG) were isolated from lesions of infected birds. MG was also isolated from a blue jay (Cyanocitta cristata) that contracted conjunctivitis after being housed in a cage previously occupied by house finches with conjunctivitis, and from free-ranging American goldfinches (Carduelis tristis) in North Carolina in 1996. To investigate the molecular epidemiology of this outbreak, we produced DNA fingerprints of MG isolates by random amplification of polymorphic DNA (RAPD). We compared MG isolates from songbirds examined from 1994 through 1996 in 11 states, representing three host species, with vaccine and reference strains and with contemporary MG isolates from commercial poultry. All MG isolates from songbirds had RAPD banding patterns identical to each other but different from other strains and isolates tested. These results indicate that the outbreak of MG in songbirds is caused by the same strain, which suggests a single source; the outbreak is not caused by the vaccine or reference strains analyzed; and MG infection has not been shared between songbirds and commercial poultry
Detecting the direction of a signal on high-dimensional spheres: Non-null and Le Cam optimality results
We consider one of the most important problems in directional statistics,
namely the problem of testing the null hypothesis that the spike direction
of a Fisher-von Mises-Langevin distribution on the -dimensional
unit hypersphere is equal to a given direction . After a reduction
through invariance arguments, we derive local asymptotic normality (LAN)
results in a general high-dimensional framework where the dimension goes
to infinity at an arbitrary rate with the sample size , and where the
concentration behaves in a completely free way with , which
offers a spectrum of problems ranging from arbitrarily easy to arbitrarily
challenging ones. We identify various asymptotic regimes, depending on the
convergence/divergence properties of , that yield different
contiguity rates and different limiting experiments. In each regime, we derive
Le Cam optimal tests under specified and we compute, from the Le Cam
third lemma, asymptotic powers of the classical Watson test under contiguous
alternatives. We further establish LAN results with respect to both spike
direction and concentration, which allows us to discuss optimality also under
unspecified . To investigate the non-null behavior of the Watson test
outside the parametric framework above, we derive its local asymptotic powers
through martingale CLTs in the broader, semiparametric, model of rotationally
symmetric distributions. A Monte Carlo study shows that the finite-sample
behaviors of the various tests remarkably agree with our asymptotic results.Comment: 47 pages, 4 figure
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