Similarity decay of enstrophy in an electron fluid.

A similarity decay law is proposed for enstrophy of a one-signed-vorticity fluid in a circular free-slip domain. It excludes the metastable equilibrium enstrophy which cannot drive turbulence, and approaches Batchelor's t(-2) law for strong turbulence. Measurements of the decay of a turbulent electron fluid agree well with the predictions of the decay law for a variety of initial conditions.

Hydrodynamic relaxation of an electron plasma to a near-maximum entropy state.

Dynamical relaxation of a pure electron plasma in a Malmberg-Penning trap is studied, comparing experiments, numerical simulations and statistical theories of weakly dissipative two-dimensional (2D) turbulence. Simulations confirm that the dynamics are approximated well by a 2D hydrodynamic model. Statistical analysis favors a theoretical picture of relaxation to a near-maximum entropy state with constrained energy, circulation, and angular momentum. This provides evidence that 2D electron fluid relaxation in a turbulent regime is governed by principles of maximum entropy.

Mating activity of Bactrocera cacuminata (Hering) (Diptera: Tephritidae) on its larval host plant Solanum mauritianum Scopoli in southeast Queensland.

A detailed study was conducted on the mating behaviour of Bactrocera cacuminata (Hering) (Diptera: Tephritidae) in nature. Plant tissues from Solanum mauritianum Scopoli, the primary larval host for B. cacuminata, were also analysed for methyl eugenol content. In the field, over a 15 month period, 44,171 observations of adult B. cacuminata individuals were made including 1109 mating pairs on S. mauritianum. Calling behaviour consisting of wing fanning and anus beating by males was also consistently observed on the underside of leaves of S. mauritianum after sunset. Female flies that arrived into these groups of 10-15 calling males were mated and often remained coupled until dawn. No methyl eugenol was detected from the analysis of leaves, flowers and fruits of S. mauritianum. Thus, B. cacuminata does not need to aggregate at sites where methyl eugenol is present and the hypothesis that this chemical plays a role in the selection of mating sites by B. cacuminata is not supported by the current study. It is concluded that S. mauritianum is the primary site of mating for B. cacuminata in nature and that the concept that the larval host plant is the centre of activity for dacine fruit flies remains robust, being fully supported by the results of this study.

Influenza immunization rates in the Intermountain End-Stage Renal Disease Network (Network 15).

Billing data from the Health Care Financing Administration (HCFA) indicated that the influenza immunization rates for dialysis patients in the United States do not meet the goal of 60% set by Healthy People 2000, and fall significantly short of the goal of 90% of all Medicare beneficiaries as outlined in Healthy People 2010. Influenza and pneumonia together are the sixth leading cause of death in the United States. Despite the known benefits of influenza vaccination in reducing morbidity and mortality, only 40% to 50% of high-risk patients are immunized. Although HCFA/Medicare billing data may not provide the best measurement of actual practice, it is currently the only measure available from any national source. The data suggest that there is a need for improvement. Because the HCFA/Medicare rates were based only on those immunizations for which Medicare was billed, End-Stage Renal Disease Network 15 embarked on a project to determine a more accurate rate of immunization within the Network based on information provided by the dialysis facilities. Influenza vaccination rates for the winter 1998 flu season ranged from 51.5% to 84.9% for the states in the Network; the rate for the whole Network was 74.6%. The HCFA/Medicare billed influenza immunization rates were 26.5 to 45.6 percentage points lower.

Exit-site care--is it time for a change?

Peritoneal catheter exit-site infections (ESI's) continue to impact significantly on morbidity and catheter longevity. The controversy concerning protocols for daily exit-site care continues for frequency, methodology, cleansing agent, and dressing. Routine daily exit-site care prior to January 1991 consisted of daily showers using liquid soap, povidone scrub, rinsing the shower, and drying with a 4 x 4-in. gauze pad. Catheters have always been immobilized, either with tape or an immobilizing device. Hydrogen peroxide was used only when needed to soften crust formation prior to showering. A light dressing, usually 2 x 2 in., was optional. A recent survey revealed that povidone iodine was the antiseptic of choice for catheter care in 75% of the respondents. However, povidone iodine irritates and dries the skin predisposing it to infection. ESI's are prospectively monitored as part of our quality improvement (QI) program. An incidence of 0.76 episodes/patient-year was noted between January 1989 and May 1991. Given the relative high frequency of ESI's, the protocol was modified and introduced during the January-May 1991 time frame. Routine care now consists of daily showers using only CC-500, a gentle antibacterial cleaner (Care-Tech Laboratories, Inc.), rinsing in the shower, and drying with a 4 x 4-in. gauze. Use of hydrogen peroxide and dressings has remained the same. Additionally, a protocol addressing the prophylaxis for traumatized exist sites was initiated. The incidence of ESI's has dropped significantly to 0.12 episodes/patient-year. Although our population size is small (n = 18), this study does point out the utility of prospectively monitoring trends for appropriate indicators within a QI program.(ABSTRACT TRUNCATED AT 250 WORDS)