Supercooling of the A phase of 3He.

Because of the extreme purity, lack of disorder, and complex order parameter, the first-order superfluid 3He A-B transition is the leading model system for first order transitions in the early universe. Here we report on the path dependence of the supercooling of the A phase over a wide range of pressures below 29.3 bar at nearly zero magnetic field. The A phase can be cooled significantly below the thermodynamic A-B transition temperature. While the extent of supercooling is highly reproducible, it depends strongly upon the cooling trajectory: The metastability of the A phase is enhanced by transiting through regions where the A phase is more stable. We provide evidence that some of the additional supercooling is due to the elimination of B phase nucleation precursors formed upon passage through the superfluid transition. A greater understanding of the physics is essential before 3He can be exploited to model transitions in the early universe.

Inverse cascade in decaying three-dimensional magnetohydrodynamic turbulence.

We perform direct numerical simulations of three-dimensional freely decaying magnetohydrodynamic turbulence. For helical magnetic fields, an inverse cascade effect is observed in which power is transferred from smaller scales to larger scales. The magnetic field reaches a scaling regime with self-similar evolution, and power-law behavior at high wave numbers. We also find power-law decay in the magnetic and kinematic energies, and power-law growth in the characteristic length scale of the magnetic field.

Measuring clinical performance: comparison and validity of telephone survey and administrative data.

OBJECTIVE: To compare and validate self-reported telephone survey and administrative data for two Health Plan Employer Data and Information Set (HEDIS) performance measures: mammography and diabetic retinal exams. DATA SOURCES/STUDY SETTING: A telephone survey was administered to approximately 700 women and 600 persons with diabetes randomly chosen from each of two health maintenance organizations (HMOs). STUDY DESIGN: Agreement of survey and administrative data was assessed by using kappa coefficients. Validity measures were assessed by comparing survey and administrative data results to a standard: when the two sources agreed, that was accepted as the standard; when they differed, confirmatory information was sought from medical records to establish the standard. When confirmatory information was not available ranges of estimates consistent with the data were constructed by first assuming that all persons for whom no information was available had received the service and alternately that they had not received the service. PRINCIPAL FINDINGS: The kappas for mammography were .65 at both HMOs; for retinal exam they were .38 and .40. Sensitivity for both data sources was consistently high. However, specificity was lower for survey (range .44 to .66) than administrative data (.99 to 1.00). The positive predictive value was high for mammography using either data source but differed for retinal exam (survey .69 to .78; administrative data .99 to 1.00). CONCLUSIONS: Administrative and survey data performed consistently in both HMOs. Although administrative data appeared to have greater specificity than survey data the validity and utility of different data sources for performance measurement have only begun to be explored.

Improving chronic illness care: translating evidence into action.

The growing number of persons suffering from major chronic illnesses face many obstacles in coping with their condition, not least of which is medical care that often does not meet their needs for effective clinical management, psychological support, and information. The primary reason for this may be the mismatch between their needs and care delivery systems largely designed for acute illness. Evidence of effective system changes that improve chronic care is mounting. We have tried to summarize this evidence in the Chronic Care Model (CCM) to guide quality improvement. In this paper we describe the CCM, its use in intensive quality improvement activities with more than 100 health care organizations, and insights gained in the process.

Defect formation and local gauge invariance

We propose a new mechanism for formation of topological defects in a U(1) model with a local gauge symmetry. This mechanism leads to definite predictions, which are qualitatively different from those of the Kibble-Zurek mechanism of global theories. We confirm these predictions in numerical simulations, and they can also be tested in superconductor experiments. We believe that the mechanism generalizes to more complicated theories.

The role of tobacco intervention in population-based health care: a case study.

Managed care organizations are in an excellent position to implement population-based, as well as patient-centered, approaches to reduce behavioral risk factors associated with major chronic diseases. Group Health Cooperative of Puget Sound employed a population-based model for smoking that contributed to a decrease from 25% to 15.5% in smoking prevalence in 10 years among its more than 550,000 adult enrollees in western Washington. This model may have application to other arenas where health systems can support beneficial behavior change.

A population-based approach to diabetes management in a primary care setting: early results and lessons learned.

OBJECTIVE: To determine the effect of a multifaceted program of support on the ability of primary care teams to deliver population-based diabetes care. DESIGN: Ongoing evaluation of a population-based intervention. SETTING/PARTICIPANTS: Group Health Cooperative of Puget Sound, a staff model HMO in which more than 200 primary care providers treat approximately 15,000 diabetic patients. INTERVENTION: A program of support to improve the ability of primary care teams to deliver population-based diabetes care was implemented. The elements of the program are based on an integrated model of well-validated components of delivery of effective care to chronically ill populations. These elements have been introduced since the beginning of 1995, and some aspects of the program were pilot-tested in a few practice sites before being implemented throughout the organization. The program elements include 1) a continually updated on-line registry of diabetic patients; 2) evidence-based guidelines on retinal screening, foot care, screening for microalbuminuria, and glycemic management; 3) improved support for patient self-management; 4) practice redesign to encourage group visits for diabetic patients in the primary care setting; and 5) decentralized expertise through a diabetes expert care team (a diabetologist and a nurse certified diabetes educator) seeing patients jointly with primary care teams. MAIN OUTCOME MEASURES: Patient and provider satisfaction through existing system-wide measurement processes; process measures, health outcomes, and costs are tracked continuously. RESULTS: Patient and provider satisfaction have improved steadily. Interest in and use of the electronic Diabetes Registry have grown considerably. Rates of retinal eye screening, documented foot examinations, and testing for microalbuminuria and hemoglobin A1c have increased substantially. CONCLUSIONS: Providing support to primary care teams in several key areas has made a population-based approach to diabetes care a practical reality in the setting of a staff model HMO. It may be an important mechanism for improving standards of care for many diabetic patients.

Sheep mortality associated with paralytic shellfish poisons from the cyanobacterium Anabaena circinalis.

This is the first report of sheep mortalities associated with paralytic shellfish poisons (PSPs) from the cyanobacterium Anabaena circinalis Rabenhorst. Fourteen sheep died within 150 m of a farm dam containing a dense bloom of A. circinalis. Extracts from both the cyanobacterium and small intestine from a dead ewe were analysed by high-performance liquid chromtography (HPLC) and found to contain PSPs. The toxin profiles of the cyanobacterium contained a high proportion of C-toxins (70%), whereas toxins in the small intestine content were dominated by gonyautoxin 5 (87%). This observation could be explained by desulfation of the C-toxins in the gut of the sheep. The LD100 of bloom material calculated from HPLC data was consistent with mouse bioassay data (12-25 mg/kg). The symptoms of affected sheep, mouse bioassay data, coupled with HPLC analysis of toxins from the bloom samples and the intestine contents, and the absence of other cyanobacterial alkaloid toxins, indicate that PSPs were responsible for the deaths of the sheep.

Seroprevalence to Leptospira interrogans serovar hardjo in merino stud rams in South Australia.

A serological survey of 2160 Merino stud rams on 36 farms detected positive reactions greater than or equal to 1/100 in 42% of animals using the microscopic agglutination test (MAT) to Leptospira interrogans serovar hardjo. Twenty flocks had seroprevalence values greater than 30% with 15 flocks having values > or = 60%. The enzyme-linked immunosorbent assays showed that 47% and 3% of rams on the 36 farms were positive for IgG and IgM antibodies, respectively. Forty-five percent of hardjo reactions were in rams that had not been exposed to cattle. Significant correlations were found between IgM reactors and creek/dam water pumped into troughs, and between MAT/IgG reactors and total flock size. No statistical relationships were detected between positive reactors and two different annual average rainfall gradients, the time of the year in which samples were obtained, or agricultural regions of South Australia. Infections with an organism of the Sejroe serogroup is widespread in Merino stud rams.