1,324 research outputs found
The Yellowstone Permutation
Define a sequence of positive integers by the rule that a(n) = n for 1 <= n
= 4, a(n) is the smallest number not already in the sequence
which has a common factor with a(n-2) and is relatively prime to a(n-1). We
show that this is a permutation of the positive integers. The remarkable graph
of this sequence consists of runs of alternating even and odd numbers,
interrupted by small downward spikes followed by large upward spikes,
suggesting the eruption of geysers in Yellowstone National Park. On a larger
scale the points appear to lie on infinitely many distinct curves. There are
several unanswered questions concerning the locations of these spikes and the
equations for these curves.Comment: 10 pages, 6 figures. Mar 7 2015: mostly stylistic change
Evaluation of the Wellspring Model for Improving Nursing Home Quality
Examines how successfully the Wellspring model improved the quality of care for residents of eleven nonprofit nursing homes in Wisconsin. Looks at staff turnover, and evaluates the impact on facilities, employees, residents, and cost
Enteroaggregative Escherichia coli as a Potential Cause of Diarrheal Disease in Adults Infected with Human Immunodeficiency Virus
Stools of 68 human immunodeficiency virus (HIV)-infected adults with diarrhea and 60 without diarrhea were examined for enteroaggregative Escherichia coli (EAggEc) by HeLa cell adherence assay. EAggEc were present in stools of 30 patients with and 18 without diarrhea (P = .05). CD4 cell counts of patients with EAggEc and diarrhea were significantly lower than those of patients with EAggEc without diarrhea (P = .02). There was no difference in the mean duration of diarrheal symptoms or in the number of stools per day between patients with EAggEc and those without. None of the EAggEc strains were positive by polymerase chain reaction for adherence fimbria, but 11 strains were positive for EAggEc heat-stable toxin EAST/1. Of the EAggEc strains, 51% were resistant to trimethoprim-sulfamethoxazole and 65% were resistant to ampicillin. EAggEc may be a pathogen in HIV-infected patients with diarrhea; HIV-infected patients with EAggEc appear to be more symptomatic when HIV disease is more advance
Bogomol'nyi Limit For Magnetic Vortices In Rotating Superconductor
This work is the sequel of a previous investigation of stationary and
cylindrically symmetric vortex configurations for simple models representing an
incompressible non-relativistic superconductor in a rigidly rotating
background. In the present paper, we carry out our analysis with a generalized
Ginzburg-Landau description of the superconductor, which provides a
prescription for the radial profile of the normal density within the vortex.
Within this framework, it is shown that the Bogomol'nyi limit condition marking
the boundary between type I and type II behavior is unaffected by the rotation
of the background.Comment: 7 pages, uses RevTeX, submitted to Phys.Rev.
- …