Compositional controls on oceanic plates : geophysical evidence from the MELT area

Author Posting. © The Authors, 2005. This is the author's version of the work. It is posted here by permission of Nature Publishing Group for personal use, not for redistribution. The definitive version was published in Nature 437 (2005): 249-252, doi:10.1038/nature04014.Magnetotelluric (MT) and seismic data, collected during the MELT experiment at the Southern East Pacific Rise (SEPR) constrain the distribution of melt beneath this mid-ocean-ridge spreading center and also the evolution of the oceanic lithosphere during its early cooling history. In this paper, we focus on structure imaged at distances ~100 to 350 km east of the ridge crest, corresponding to seafloor ages of ~1.3 to 4.5 Ma, where the seismic and electrical conductivity structure is nearly constant, independent of age. Beginning at a depth of about 60 km, there is a large increase in electrical conductivity and a change from isotropic to transversely anisotropic electrical structure with higher conductivity in the direction of fast propagation for seismic waves. Because conductive cooling models predict structure that increases in depth with age, extending to about 30 km at 4.5 Ma, we infer that the structure of young oceanic plates is instead controlled by a decrease in water content above 60 km induced by the melting process beneath the spreading center.US participation in the MELT experiment and subsequent analysis was funded by NSF grants through the Marine Geology and Geophysics Program, Ocean Sciences Division

Over and Under-utilization of Cyclooxygenase-2 Selective Inhibitors by Primary Care Physicians and Specialists: The Tortoise and the Hare Revisited

To compare prescribing trends and appropriateness of use of traditional and cyclooxygenase-2 selective (COX-2) nonsteroidal anti-inflammatory drugs (NSAIDs) by primary care physicians (PCPs) and specialists. DESIGN : Retrospective cohort study. PATIENTS : One thousand five hundred and seventy-six adult patients continuously enrolled for at least 1 year with an independent practice association of a University-associated managed care plan who were started on a traditional NSAID or a COX-2 inhibitor from 1999 to 2002 and received at least 3 separate medication fills. MEASUREMENTS : Physician specialty was identified from office visits. Appropriateness of utilization was based on gastrointestinal risk characteristics. RESULTS : Primary care patients were younger and less likely to have comorbid conditions. Despite similar GI risk, COX-2 use among patients seen by PCPs was half that of patients seen by specialists (21% vs 44%, P <.001). While PCPs overused cyclooxygenase-2-specific inhibitors (COX-2s) less often than specialists (19% vs 41%, P <.001), they also tended to underuse COX-2s in patients who were at increased GI risk (46% vs 32%, P =.063). This represents a 3-fold and 8-fold difference in overuse versus underuse for PCPs and specialists, respectively. CONCLUSIONS : Using COX-2s as a model for physician adoption of new therapeutic agents, specialists were more likely to use these new medications for patients likely to benefit but were also significantly more likely to use them for patients without a clear indication. This study demonstrates the tension between appropriate adoption of innovative therapies for those individuals who would benefit from their use and those individuals who would receive no added clinical benefit but would incur added cost and be placed at increased risk.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75173/1/j.1525-1497.2006.00463.x.pd

The social value of a QALY : raising the bar or barring the raise?

Background: Since the inception of the National Institute for Health and Clinical Excellence (NICE) in England, there have been questions about the empirical basis for the cost-per-QALY threshold used by NICE and whether QALYs gained by different beneficiaries of health care should be weighted equally. The Social Value of a QALY (SVQ) project, reported in this paper, was commissioned to address these two questions. The results of SVQ were released during a time of considerable debate about the NICE threshold, and authors with differing perspectives have drawn on the SVQ results to support their cases. As these discussions continue, and given the selective use of results by those involved, it is important, therefore, not only to present a summary overview of SVQ, but also for those who conducted the research to contribute to the debate as to its implications for NICE. Discussion: The issue of the threshold was addressed in two ways: first, by combining, via a set of models, the current UK Value of a Prevented Fatality (used in transport policy) with data on fatality age, life expectancy and age-related quality of life; and, second, via a survey designed to test the feasibility of combining respondents’ answers to willingness to pay and health state utility questions to arrive at values of a QALY. Modelling resulted in values of £10,000-£70,000 per QALY. Via survey research, most methods of aggregating the data resulted in values of a QALY of £18,000-£40,000, although others resulted in implausibly high values. An additional survey, addressing the issue of weighting QALYs, used two methods, one indicating that QALYs should not be weighted and the other that greater weight could be given to QALYs gained by some groups. Summary: Although we conducted only a feasibility study and a modelling exercise, neither present compelling evidence for moving the NICE threshold up or down. Some preliminary evidence would indicate it could be moved up for some types of QALY and down for others. While many members of the public appear to be open to the possibility of using somewhat different QALY weights for different groups of beneficiaries, we do not yet have any secure evidence base for introducing such a system

Observational Evidence of For-Profit Delivery and Inferior Nursing Home Care: When Is There Enough Evidence for Policy Change?

This research was financially supported by the Social Sciences and Humanities Research Council

Can differences in medical drug compliance between European countries be explained by social factors: analyses based on data from the European Social Survey, round 2

<p>Abstract</p> <p>Background</p> <p>Non-compliance with medication is a major health problem. Cultural differences may explain different compliance patterns. The size of the compliance burden and the impact of socio-demographic and socio-economic status within and across countries in Europe have, however, never been analysed in one survey. The aim of this study was to analyse 1) medical drug compliance in different European countries with respect to socio-demographic and socio-economic factors, and to examine 2) whether cross-national differences could be explained by these factors.</p> <p>Methods</p> <p>A multi-country interview survey <it>European Social Survey, Round 2 </it>was conducted in 2004/05 comprising questions about compliance with last prescribed drug. Non-compliance was classified as primary and secondary, depending whether the drug was purchased or not. Statistical weighting allowed for adjustment for national differences in sample mechanisms. A multiple imputation strategy was used to compensate for missing values. The analytical approach included multivariate and multilevel analyses.</p> <p>Results</p> <p>The survey comprised 45,678 participants. Response rate was 62.5% (range 43.6–79.1%). Reported compliance was generally high (82%) but the pattern of non-compliance showed large variation between countries. Some 3.2% did not purchase the most recently prescribed medicine, and 13.6% did not take the medicine as prescribed. Multiple regression analyses showed that each variable had very different and in some cases opposite impact on compliance within countries. The multilevel analysis showed that the variation between countries did not change significantly when adjusted for increasing numbers of covariates.</p> <p>Conclusion</p> <p>Reported compliance was generally high but showed wide variation between countries. Cross-national differences could, however, not be explained by the socio-demographic and socio-economic variables measured.</p

Duration of temporary catheter use for hemodialysis: an observational, prospective evaluation of renal units in Brazil

<p>Abstract</p> <p>Background</p> <p>For chronic hemodialysis, the ideal permanent vascular access is the arteriovenous fistula (AVF). Temporary catheters should be reserved for acute dialysis needs. The AVF is associated with lower infection rates, better clinical results, and a higher quality of life and survival when compared to temporary catheters. In Brazil, the proportion of patients with temporary catheters for more than 3 months from the beginning of therapy is used as an evaluation of the quality of renal units. The aim of this study is to evaluate factors associated with the time between the beginning of hemodialysis with temporary catheters and the placement of the first arteriovenous fistula in Brazil.</p> <p>Methods</p> <p>This is an observational, prospective non-concurrent study using national administrative registries of all patients financed by the public health system who began renal replacement therapy (RRT) between 2000 and 2004 in Brazil. Incident patients were eligible who had hemodialysis for the first time. Patients were excluded who: had hemodialysis reportedly started after the date of death (inconsistent database); were younger than 18 years old; had HIV; had no record of the first dialysis unit; and were dialyzed in units with less than twenty patients. To evaluate individual and renal unit factors associated with the event of interest, the frailty model was used (N = 55,589).</p> <p>Results</p> <p>Among the 23,824 patients (42.9%) who underwent fistula placement in the period of the study, 18.2% maintained the temporary catheter for more than three months until the fistula creation. The analysis identified five statistically significant factors associated with longer time until first fistula: higher age (Hazard-risk - HR 0.99, 95% CI 0.99-1.00); having hypertension and cardiovascular diseases (HR 0.94, 95% CI 0.9-0.98) as the cause of chronic renal disease; residing in capitals cities (HR 0.92, 95% CI 0.9-0.95) and certain regions in Brazil - South (HR 0.83, 95% CI 0.8-0.87), Midwest (HR 0.88, 95% CI 0.83-0.94), Northeast (HR 0.91, 95% CI 0.88-0.94), or North (HR 0.88, 95% CI 0.83-0.94) and the type of renal unit (public or private).</p> <p>Conclusion</p> <p>Monitoring the provision of arteriovenous fistulas in renal units could improve the care given to patients with end stage renal disease.</p

Payments and quality of care in private for-profit and public hospitals in Greece

<p>Abstract</p> <p>Background</p> <p>Empirical evidence on how ownership type affects the quality and cost of medical care is growing, and debate on these topics is ongoing. Despite the fact that the private sector is a major provider of hospital services in Greece, little comparative information on private versus public sector hospitals is available. The aim of the present study was to describe and compare the operation and performance of private for-profit (PFP) and public hospitals in Greece, focusing on differences in nurse staffing rates, average lengths of stay (ALoS), and Social Health Insurance (SHI) payments for hospital care per patient discharged.</p> <p>Methods</p> <p>Five different datasets were prepared and analyzed, two of which were derived from information provided by the National Statistical Service (NSS) of Greece and the other three from data held by the three largest SHI schemes in the country. All data referred to the 3-year period from 2001 to 2003.</p> <p>Results</p> <p>PFP hospitals in Greece are smaller than public hospitals, with lower patient occupancy, and have lower staffing rates of all types of nurses and highly qualified nurses compared with public hospitals. Calculation of ALoS using NSS data yielded mixed results, whereas calculations of ALoS and SHI payments using SHI data gave results clearly favoring the public hospital sector in terms of cost-efficiency; in all years examined, over all specialties and all SHI schemes included in our study, unweighted ALoS and SHI payments for hospital care per discharge were higher for PFP facilities.</p> <p>Conclusions</p> <p>In a mixed healthcare system, such as that in Greece, significant performance differences were observed between PFP and public hospitals. Close monitoring of healthcare provision by hospital ownership type will be essential to permit evidence-based decisions on the future of the public/private mix in terms of healthcare provision.</p

Insights from a national survey into why substance abuse treatment units add prevention and outreach services

BACKGROUND: Previous studies have found that even limited prevention-related interventions can affect health behaviors such as substance use and risky sex. Substance abuse treatment providers are ideal candidates to provide these services, but typically have little or no financial incentive to do so. The purpose of this study was therefore to explore why some substance abuse treatment units have added new prevention and outreach services. Based on an ecological framework of organizational strategy, three categories of predictors were tested: (1) environmental, (2) unit-level, and (3) unit leadership. RESULTS: A lagged cross-sectional logistic model of 450 outpatient substance abuse treatment units revealed that local per capita income, mental health center affiliation, and clinical supervisors' graduate degrees were positively associated with likelihood of adding prevention-related education and outreach services. Managed care contracts and methadone treatment were negatively associated with addition of these services. No hospital-affiliated agencies added prevention and outreach services during the study period. CONCLUSION: Findings supported the study's ecological perspective on organizational strategy, with factors at environmental, unit, and unit leadership levels associated with additions of prevention and outreach services. Among the significant predictors, ties to managed care payers and unit leadership graduate education emerge as potential leverage points for public policy. In the current sample, units with managed care contracts were less likely to add prevention and outreach services. This is not surprising, given managed care's emphasis on cost control. However, the association with this payment source suggests that public managed care programs might affects prevention and outreach differently through revised incentives. Specifically, government payers could explicitly compensate substance abuse treatment units in managed care contracts for prevention and outreach. The effects of supervisor graduate education on likelihood of adding new prevention and outreach programs suggests that leaders' education can affect organizational strategy. Foundation and government officials may encourage prevention and outreach by funding curricular enhancements to graduate degree programs demonstrating the importance of public goods. Overall, these findings suggest that both money and professional education affect substance abuse treatment unit additions of prevention and outreach services, as well as other factors less amenable to policy intervention