Transition from Ekman flow to Taylor vortex flow in superfluid helium

By numerically computing the steady axisymmetric flow of helium II confined inside a finite aspect ratio Couette annulus, we determine the transition from Ekman flow to Taylor vortex flow as a function of temperature and aspect ratio.We find that the low-Reynolds number flow is quite different to that of a classical fluid, particularly at lower temperatures.At high aspect ratio our results confirm the existing linear stability theory of the onset of Taylor vortices, which assumes infinitely long cylinders.Comment: 12 pages, 8 figures; submitte

Magnetic shell enhancements during magnetic disturbances

Magnetic shell enhancements during magnetic field disturbances from Langmuir probe observations of electron density on Ariel I satellit

Red abalone size data from Johnsons Lee, Santa Rosa Island, collected from 1978 to 1984

Red abalone, Haliotis rufescens, were collected at Johnsons Lee, Santa Rosa Island, in the summers of 1978 through 1982, and in 1984, to obtain data for determining various fishery population parameters. Annual visits to the study site were made at yearly intervals to simplify growth calculations. During the first four visits, 2145 red abalones were tagged, measured, and replaced. Shell damage, soft tissue injuries, and causes of mortality were noted. The method of tagging is described. Recovery of first tagged abalone after one year was approximately 30%. Analysis of variance of the annual samples indicated that the samples were, with one exception, not different. Summaries are presented of the number of abalone collected and tagged by year, frequencies of shell damage, soft tissue injury, predatory sponge infestation, and total mortality. Appendices include a listing of the raw size data and various codes for each tagged abalone. (56pp.

On Quantum Algorithms

Quantum computers use the quantum interference of different computational paths to enhance correct outcomes and suppress erroneous outcomes of computations. In effect, they follow the same logical paradigm as (multi-particle) interferometers. We show how most known quantum algorithms, including quantum algorithms for factorising and counting, may be cast in this manner. Quantum searching is described as inducing a desired relative phase between two eigenvectors to yield constructive interference on the sought elements and destructive interference on the remaining terms.Comment: 15 pages, 8 figure

Struggling to a monumental triumph : Re-assessing the final stages of the smallpox eradication program in India, 1960-1980

The global smallpox program is generally presented as the brainchild of a handful of actors from the WHO headquarters in Geneva and at the agency's regional offices. This article attempts to present a more complex description of the drive to eradicate smallpox. Based on the example of India, a major focus of the campaign, it is argued that historians and public health officials should recognize the varying roles played by a much wider range of participants. Highlighting the significance of both Indian and international field officials, the author shows how bureaucrats and politicians at different levels of administration and society managed to strengthen—yet sometimes weaken—important program components. Centrally dictated strategies developed at WHO offices in Geneva and New Delhi, often in association with Indian federal authorities, were reinterpreted by many actors and sometimes changed beyond recognition

Alsophis antiguae

Number of Pages: 3Integrative BiologyGeological Science