bluuebunny/crossref_metadata_2025 huggingface dataset:
Morphological insensitivity in second language processing
Authors: JIANG NAN
Published: May 2008

Two competing explanations exist regarding the nature of morphological difficulty in adult second language acquisition: competence deficit versus performance deficiency. This study tested these explanations by examining English as a second language (ESL) learners' morphological performance in reading comprehension tasks. Chinese ESL speakers were asked to read English sentences for comprehension in three self-paced word by word reading experiments. Their reading times were measured to determine if they were sensitive to idiosyncrasies/disagreement in sentences that do and do not involve the number morpheme. The results show that they are not sensitive to number disagreement, but sensitive to other idiosyncrasies tested. This insensitivity to the number morpheme suggests that their morphological knowledge is not an integrated part of their automatic second language competence.
The application of flash-over switch in high energy fluence diode
Authors: Zhang Yongmin , Tang Junping , Huang Jianjun , Qiu Aici , Guan Zhicheng , Wang Xinxin
Published: May 2008

In order to restrain the prepulse of a high energy fluence diode, a flash-over switch made of a nylon cylinder was inserted in between the cathode stalk and the cathode. Secondary prepulse technique was developed to lower the flash-over voltage of the switch. It was found that the surface resistivity of the nylon insulator changes considerably after each shot and this resistivity on the order of 107 Ω/m is most suitable for a 20-mm long flash-over switch to operate stably at a lower flash-over voltage.
Investigations on low temperature laser-generated plasmas
Authors: Caridi F. , Torrisi L. , Margarone D. , Borrielli A.
Published: May 2008

A nanosecond pulsed Nd-Yag laser, operating at an intensity of about 109 W/cm2, was employed to irradiate different metallic solid targets (Al, Cu, Ta, W, and Au) in vacuum. The measured ablation yield increases with the direct current (dc) electrical conductivity of the irradiated target. The produced plasma was characterized in terms of thermal and Coulomb interaction evaluating the ion temperature and the ion acceleration voltage developed in the non-equilibrium plasma core. The particles emission produced along the normal to the target surface was investigated measuring the neutral and the ion energy distributions and fitting the experimental data with the “Coulomb-Boltzmann-shifted” function. Results indicate that the mean energy of the distributions and the equivalent ion acceleration voltage of the non-equilibrium plasma increase with the free electron density of the irradiated element.
Force-closure analysis of 6-DOF cable manipulators with seven or more cables
Authors: Diao Xiumin , Ma Ou
Published: May 2008

A cable manipulator controls its end-effector by a number of cables. If the cables can balance any external and inertia wrenches at a certain pose of the end-effector, the cable manipulator is said to have a force-closure at this pose. Since a cable can work only in tension, the force-closure at a specific pose may not exist. Thus, how to check the existence of force-closure at a given pose is an important issue for design and control of cable manipulators. This paper describes a systematic method of verifying the existence of force-closure at a specific pose of a general 6-DOF cable manipulator with seven or more cables. By examining the Jacobian matrix of the manipulator, the method can determine whether a force-closure exists at the pose corresponding to the Jacobian matrix. The necessity and sufficiency of the proposed method are mathematically proven. Moreover, a convex-analysis-based simplification of the method for manipulators with more than seven cables is also discussed.
A hand–eye calibration algorithm based on screw motions
Authors: Zhao Zijian , Liu Yuncai
Published: May 2008

When computer vision technique is used in robotics, robotic hand–eye calibration is a very important research task. Many algorithms have been proposed for hand–eye calibration. Based on these algorithms, we introduce a new hand–eye calibration algorithm in this paper, which employs the screw motion theory to establish a hand–eye matrix equation by using quaternion and gets a simultaneous result for rotation and translation by solving linear equations. The algorithm proposed in this paper has high accuracy and stable computational efficiency and can be understood easily. Both simulations and real experiments show the superiority of our algorithm over the comparative algorithms.
INTRODUCTION
Authors: Barnett David , Taylor Rod
Published: May 2008

This special section is the written record of the second National Institute for Clinical Excellence (NICE) conference, which drew together experts in the fields of health technology assessment (HTA) from around the world. It includes a significant perspective from the pharmaceutical industry, whose partnership with the manufacturers of technologies (pharmaceuticals, devices, etc.) is of paramount importance to the successful future of the input of HTA into healthcare delivery. The importance of HTA as the basis of clinical decision making has never been more apparent. All clinicians are aware of the requirement that they provide the most up-to-date health care for their patients, who in turn appropriately consider this as a right. The need to ensure that this care is based on reliable evidence of clinical effectiveness is paramount. In addition, the need for all healthcare systems to consider costs as well as benefits has led to a further imposition on those who provide care to take into account value for money when considering the implementation of a new technology.
HEALTH TECHNOLOGY ASSESSMENT FOR THE NHS IN ENGLAND AND WALES
Authors: Woods Kent
Published: May 2008

In healthcare decision making, there is an important functional separation between assessment and appraisal. In the U.K. National Health Service (NHS), this distinction is illustrated by the separation of roles between the Health Technology Assessment Programme and the National Institute for Clinical Excellence. However, it can be seen at every level within the healthcare system. Assessment of a technology is a scientific task that synthesizes all relevant evidence on effectiveness and cost-effectiveness; its results are therefore generalizable. Appraisal of the technology is informed by the assessment but adds context-specific judgments on the applicability of the evidence, the feasibility and impact of alternative options, relative priorities, and wider social and ethical aspects. An explicit distinction between assessment and appraisal is helpful in achieving clarity, consistency, and consensus. It also makes clear the need for a wide range of assessment reviews to support decision making by commissioners, providers, and users of health services. Increasingly, the secondary research supported by the NHS R&D Programme is being distributed electronically. It is also being used to identify areas in which further primary research should be commissioned.
DEVELOPMENT OF HEALTH TECHNOLOGY ASSESSMENT IN EUROPE
Authors: Jonsson Egon
Published: May 2008

Health technology assessment (HTA) grew from a need recognized by researchers concerned about the effectiveness of health services. They were later joined by policy makers in search of valid information about the costs and benefits of investments in health care. The history of HTA shows that this need appeared in many countries at nearly the same time.
SYSTEMS FOR ROUTINE INFORMATION SHARING IN HTA
Authors: Hagenfeldt Kerstin , Asua José , Bellucci Sergio , Jensen Malene Fabricius , Mørland Berit , Oortwijn Wija , Salmi Rachid , Stevens Andrew , ten Velden Gabriël H. M.
Published: May 2008

The aim of Working Group 2 has been to develop a system for routine exchange of information concerning ongoing or planned evaluations and their findings, priority setting, and emerging technology.
EDUCATION AND SUPPORT NETWORKS FOR ASSESSMENT OF HEALTH INTERVENTIONS
Authors: Kristensen Finn Børlum , Gabbay John , Antes Gert , Briones Eduardo , Britton Mona , Burnand Bernard , Engel Gerard , Gallo Pedro , Pinto Carlos Gouveia , Siebzehner Miriam Ines , Jönsson Bengt , Landa Krzysztof , Liaropoulos Lycurgus , Liberati Alessandro , Mäkelä Marjukka , Jensen Bo Nordby , Piestiniene Audroné , Raspe Heiner , Synnott Aidan
Published: May 2008

The aim of Working Group 5 is to develop and coordinate education and support networks for individuals and organizations undertaking or using assessment of health interventions and to identify needs in the field and assist in the establishment of new provisions.
LITERATURE SEARCHING FOR RANDOMIZED CONTROLLED TRIALS USED IN COCHRANE REVIEWS: RAPID VERSUS EXHAUSTIVE SEARCHES
Authors: Royle Pamela , Milne Ruairidh
Published: May 2008

Objectives:To analyze sources searched in Cochrane reviews, to determine the proportion of trials included in reviews that are indexed in major databases, and to compare the quality of these trials with those from other sources.

Methods:All new systematic reviews in the Cochrane Library, Issue1 2001, that were restricted to randomized controlled trials (RCTs) or quasi-RCTs were selected. The sources searched in the reviews were recorded, and the trials included were checked to see whether they were indexed in four major databases. Trials not indexed were checked to determine how they could be identified. The quality of trials found in major databases was compared with those found from other sources.

Results:The range in the number of databases searched per review ranged between one and twenty-seven. The proportion of the trials in the four databases were Cochrane Controlled Trials Register=78.5%, MEDLINE=68.8%, Embase=65.0%, and Science/Social Sciences Citation Index=60.7%. Searching another twenty-six databases after Cochrane Controlled Trials Register (CCTR), MEDLINE, and Embase only found 2.4% additional trials. There was no significant difference between trials found in the CCTR, MEDLINE, and Embase compared with other trials, with respect to adequate allocation concealment or sample size.

Conclusions:There was a large variation between reviews in the exhaustiveness of the literature searches. CCTR was the single best source of RCTs. Additional database searching retrieved only a small percentage of extra trials. Contacting authors and manufacturers to find unpublished trials appeared to be a more effective method of obtaining the additional better quality trials.
ILLUSTRATIVE ESTIMATES OF COSTS AND EFFECTS OF THE USE OF DOPPLER ULTRASONOGRAPHY IN HIGH-RISK PREGNANCIES
Authors: Westergaard Hanne Brix , Sørensen Jan , Langhoff-Roos Jens
Published: May 2008

Objectives: To examine the cost-effectiveness of Doppler ultrasonography in high-risk pregnancies.

Methods: An analysis was made of the cost-effectiveness of Doppler ultrasonography in high-risk pregnancies in relation to different organizational models. National costs of Doppler ultrasonography for singleton pregnancies with intrauterine growth retardation were estimated for three models. The cost-effectiveness analysis was based on results from a meta-analysis on clinical effects, patient costs, immediate health care costs, and costs per “saved” perinatal death.

Results: In the decentralized model (the current situation in Denmark), incremental health care costs were estimated to be 13.5 million DKK, with patient costs set at zero. In the regional and centralized models, the estimated costs were 9.3 million/0.9 million DKK and 3.4 million/2.6 million DKK, respectively. The incremental costs were more than outweighed by the savings made from significant reductions in obstetric interventions. The centralized model dominated the other two models in the cost-effective analysis. In the decentralized model, the costs of avoiding one perinatal death were estimated to be 1 million DKK. The sensitivity analysis suggested that the cost-effectiveness ratio differed considerably, depending on the assumptions used, although the rank order of the three models did not change.

Conclusions: The cost-effectiveness analysis showed that a centralized model with five obstetric centers offering Doppler ultrasonography dominates the regional and decentralized models. However, even with the decentralized model (which reflects the current situation in Denmark), the costs of avoiding one perinatal death would seem to be reasonable. In view of the paucity of available cost and effects data and the sensitivity of the results to changes in the assumptions made, more reliable information is needed before a decision can be made regarding the organization of Doppler ultrasonography for high-risk pregnancies.
APPLICATION OF A DIAGNOSTIC DECISION RULE IN CHILDREN WITH MENINGEAL SIGNS: A COST-MINIMIZATION STUDY
Authors: Oostenbrink Rianne , Oostenbrink Jan B. , Moons Karel G. M. , Derksen-Lubsen Gerarda , Grobbee Diederick E. , Redekop W. Ken , Moll Henriëtte A.
Published: May 2008

Objectives: Recently, we developed a diagnostic rule for the diagnosis and treatment of children with meningeal signs. This rule may provide the physician with a rationale to decide on the use of diagnostic and treatment procedures in these children and to improve their care. In this study, we estimated cost savings of the rule compared with current practice.

Methods: Routine care data of 360 children visiting the emergency department of the Sophia Children's Hospital with meningeal signs between 1988 and 1998 were used. Costs of diagnostic tests and treatment were estimated by using financial accounts of an academic and a general pediatric hospital. The number of procedures actually performed and the resulting cost estimates (i.e. unit costs×volume) were compared with the estimated figures after application of the decision rule.

Results: The population of children with meningeal signs comprised 99 with bacterial meningitis (27%), 36 with another serious bacterial infection (10%), and 225 with a self-limiting disease (63%). Application of the rule would reduce lumbar punctures by 12% and hospitalizations for empirical treatment by 15% with the same diagnostic accuracy as current practice. Cost savings were estimated at €292 per patient (relative reduction 10%) and were mainly achieved in the treatment course (€259).

Conclusions: A diagnostic decision rule for children with meningeal signs has the potential to improve the appropriate use of medical resources, to be cost-effective, and to ascertain the absence of bacterial meningitis earlier.
COST-EFFECTIVENESS OF ADJUNCTIVE HYPERBARIC OXYGEN IN THE TREATMENT OF DIABETIC ULCERS
Authors: Guo Shien , Counte Michael A. , Gillespie Kathleen N. , Schmitz Homer
Published: May 2008

Objectives:This study estimates the cost-effectiveness (CE) of the adjunctive use of hyperbaric oxygen (HBO2) therapy in the treatment of diabetic ulcers based on the payer's and societal perspectives.

Methods:The study population was a hypothetical cohort of 1,000 patients sixty years of age with severe diabetic foot ulcers. A decision tree model was constructed to estimate the CE of HBO2 therapy in the treatment of diabetic ulcers at years 1, 5, and 12. Scenario and one-way sensitivity analyses were also undertaken to identify parameters that may significantly influence the estimates.

Results:The CE model estimated that the incremental cost per additional quality-adjusted life year (QALY) gained at years 1, 5, and 12, was $27,310, $5,166, and $2,255, respectively.

Conclusions:The study results indicate that HBO2 therapy in the treatment of diabetic ulcers is cost-effective, particularly based on a long-term perspective. However, the results are limited by the clinical studies that provide the basis of the CE estimation.
Health technology assessment in England and Wales
Authors: Stevens Andrew , Milne Ruairidh
Published: May 2008

In this study, we describe the current state of the Health Technology Assessment (HTA) system in England and Wales. This system rests on a distinction between assessment and appraisal and has three main strands: researcher-led HTA, the research and development program, and the HTA-NICE (National Institute for Clinical Excellence) process. We outline the pressures for HTA and how it has evolved in the British National Health Service. We discuss how HTA priorities are chosen, how HTA information is collected and assessed, how HTA evidence is used, and we make some observations about its impact. In our discussion, we consider some limitations of the HTA system, its possible divergence from evidence-based health care, its centralization, and some of the key challenges for managing HTA-driven policy. But we remain hopeful that HTA can contribute to better and more explicit decision-making within England and Wales.
Technology assessment, priority setting, and appropriate care in Dutch health care
Authors: Berg Marc , van der Grinten Tom , Klazinga Niek
Published: May 2008

This article provides a critical analysis of the impact of health technology assessment (HTA) on priority setting in The Netherlands. It describes the limited steering powers of the Dutch government; its complex interactions with insurers, health-care providers, and patients; and the role of HTA in this context as an attempt to rationalize the debate about cost-effectiveness issues. HTA has been drawn upon for decision making on the health insurance package. Also, HTA findings have been linked to the national guideline development programs of the medical community. However, these impacts by no means have been straightforward. We argue that the political nature of the priority-setting debate asks for a broader approach to what constitutes HTA, and how it should be drawn upon in priority setting. Suggestions are made on how to do justice to the social dynamics of decision making and the behavior of stakeholders in health-care systems.
Health technology assessment and priority setting for health policy in Sweden
Authors: Carlsson Per
Published: May 2008

This article describes the development of health technology assessment (HTA) in Sweden, its influence on decision making, and its link with priority setting. Sweden has a well established governmental HTA body, the Swedish Council on Technology Assessment in Health Care (SBU), and an increasing number of regional/local HTA organizations. HTA has had an impact on clinical practice and is used to some extent in policy decisions. Several initiatives have now been taken to develop processes for open priority setting of health-care services. With the establishment of a new agency to undertake reimbursement decisions on pharmaceuticals, and greater patient and public involvement in decision making, it seems inevitable that HTA will play a more important role in priority setting in the near future.
Health technology assessment in four countries: response from political science
Authors: Chinitz David
Published: May 2008

Four studies, each on health technology assessment (HTA) in a different country, are presented in this volume. Conveying differing levels of sensitivity to political aspects of HTA, their storylines are similar in terms of the importance of the institutional structures that produce HTA and mediate its influence on health policy decision making. Regarding the internal politics of HTA, the latter appears to have developed in a relatively depoliticized environment, supported by a dense and varied web of institutional sites for funding, production, and consumption of HTA, buffered from the capricious impacts of electoral politics. Regarding external politics, HTA in all the countries began with relatively politically innocuous studies of technologies recognized to be of major import to national health systems or researcher-initiated studies. However, with increased focus in health systems on explicit determination of health benefits baskets, the role of HTA has become more high profile. This means that political accountability for the entire HTA process will increase. The implication is that future management of HTA programs will require self-conscious attention to the building of institutions capable of handling the delicate process of integrating science and politics in health policy.
Ethical perspectives on health technology assessment
Authors: ten Have Henk
Published: May 2008

This study analyses why ethical aspects play a minor role in health technology assessment (HTA) studies, even when comprehensive approaches of technology assessment are advocated. Technology is often regarded as a value-neutral tool. At the same time, bioethics is dominated by an engineering model. Ethical contributions to evaluation of medical technology should go beyond issues of application in clinical practice and focus also on the definition of problems, the demarcation of technical and nontechnical issues, and the morally problematic implications of technologies.
Health technology assessment and public health: a commentary
Authors: Holland Walter W.
Published: May 2008

This article reviews the developments in HTA in four countries, France, The Netherlands, Sweden, and United Kingdom, in relation to public health. It emphasizes that the majority of assessments made are concerned with individual clinical care rather than with the optimization of health. Possible reasons for the neglect of public health issues are that these are inherently more complex than the assessment of individual procedures or drugs. They are usually multisectoral, politically charged, and often considered mundane and “common sense” and, thus, not requiring evaluation (although when evaluations are done they are often counterintuitive). Unless more emphasis is given to the development and evaluation of public health measures, it is unlikely that there will be any major advances in health status. Possible areas for future assessment should include such issues as smoking, drug and other substance misuse, nutrition, and health inequalities. However, it is unlikely that these major areas of concern will be included in the future unless the methods of choice for priorities of development and assessment are changed to include measures that improve health status rather than only clinical services.
The usefulness of the NHS Economic Evaluation Database to researchers undertaking technology assessment reviews
Authors: Nixon John , Duffy Steven , Armstrong Nigel , Craig Dawn , Glanville Julie , Christie James , Drummond Michael , Kleijnen Jos
Published: May 2008

Objectives:Health-care technology reviews now increasingly include outcome costs as well as clinical effects. This study reports the findings and implications of a survey to explore the usefulness of the National Health Service Economic Evaluation Database (NHS EED) within this process.

Methods:Postal survey of lead authors of Technology Assessment Reviews (TARs) commissioned by the United Kingdom's National Institute for Clinical Excellence (NICE). The questionnaire investigated the usefulness of NHS EED in terms of (a)search strategy, (b)data extraction, (c)quality assessment, and (d)determining requirementsfornew modeling studies. Qualitative data were requested, including opinions regarding NHS EED.

Results:NHS EED was used in 90 percent of all identified reviews (n=46). The questionnaire response rate was 63 percent. The percentage of scores 3 or above (most useful), 2 or below (least useful), or N/A were, respectively, (a)search strategy=62 percent, 23 percent, 15 percent; (b)data extraction=23 percent, 27 percent, 50 percent; (c)quality assessment=38 percent, 19 percent, 42 percent; (d)determining requirements for new modeling studies=27 percent, 23 percent, 50 percent. The results were expanded further in the qualitative data from the respondents.

Conclusions:NHS EED is a useful tool for a variety of tasks in the NICE/TAR process but not, unsurprisingly, as a replacement for understanding primary studies. There is, however, a need to reduce the impact of time lags between the publication of economic evaluations and the appearance of abstracts relating to them on NHS EED. The results will inform future developments of the NHS EED database, which should increase its usefulness to researchers.
Cost-effectiveness of reduction mammaplasty
Authors: Taylor Andrew J. , Tate David , Brandberg Yvonne , Blomqvist Lennart
Published: May 2008

Objectives:The purpose of this study is to provide a comparison of the benefits of reduction mammaplasty (RM) for women with heavy breasts often termed macromastia or breast hypertrophy (BH) surgery. The rationale is to provide information to allow decision-makers to make judgments about the cost-effectiveness of this intervention and make comparisons with other interventions which are commonly undertaken within publicly financed health-care systems.

Methods:Data from a previous outcomes study in Sweden is re-analyzed to derive quality of life measures, from which a mean level of benefit outcome is derived and a cost per quality-adjusted life year is calculated (cost per QALY).

Results:The low Cost per QALY suggests that reduction mammaplasty is cost-effective when compared with other treatments which are commonly undertaken.

Conclusions:The authors suggest that the evidence in favor of funding reduction mammaplasty is strong and that decision-makers review their policy in light of this new evidence.
Assessing the economics of vaccination forNeisseria meningitidisin industrialized nations: A review and recommendations for further research
Authors: Getsios Denis , Caro Ingrid , El-Hadi Wissam , Caro Jaime J.
Published: May 2008

Objectives:To review the existing health economic literature on meningococcal disease vaccination.

Methods:A Medline search for economic evaluations of vaccination programs for meningococcal disease in developed countries was conducted. All identified studies were reviewed.

Results:Nine published studies were identified examining either mass vaccination during outbreaks or routine vaccination. Although net expenses were estimated in almost all studies, the resulting cost-effectiveness ratios varied widely. Vaccination of college-age students was found to be potentially cost-effective in Australia but not in the United States. With one exception, routine vaccination of children and adolescents in Europe was predicted to be cost-effective. Many simplifying assumptions were made, and important elements were often left out, in particular the potential for reduced transmission of disease.

Conclusions:The methods used and the vaccination strategies vary widely, and results do not provide strong grounds for making conclusions as to whether vaccination is cost-effective. Furthermore, in all instances, transmission of disease, changes in population carriage rates, and outbreaks are either ignored, dealt with using very broad simplifying assumptions, or are not necessarily generalizable to other settings. The analyses provide some insight into the potential cost-effectiveness of vaccination, but more importantly, they highlight areas requiring further study. Economic evaluations based on observed outcomes from recently implemented strategies would be helpful, as would more sophisticated health economic models. The choice of vaccination strategies cannot be based on the results of existing economic analyses.
Redefining health technology assessment in Canada: Diversification of products and contextualization of findings
Authors: Lehoux Pascale , Tailliez Stéphanie , Denis Jean-Louis , Hivon Myriam
Published: May 2008

Objectives:While strategies for enhancing the dissemination and impact of Health Technology Assessment (HTA) are now being increasingly examined, the characteristics of HTA production have received less attention.

Methods:This study presents the results of a content analysis of the HTA documents (n=187) produced by six Canadian agencies from 1995 to 2001, supplemented by interviews with chief executive officers and researchers (n=40). The goal of this analysis was to characterize the agencies' portfolios and to analyze the challenges these agencies face in responding to the increased demand for HTA.

Results:On average, thirty HTA products were issued annually by the agencies. While the bulk of documents produced were full HTA reports (76 percent), two agencies showed significant diversification in their products. Three agencies in particular actively supported the publication of results in scientific journals. Three agencies showed evidence of adapting to different institutional environments by specializing in certain areas (drugs, health services). Overall, a significant portion of the agencies' HTAs contained data on costs (37 percent) and effectiveness (48 percent), whereas ethical and social issues were rarely addressed (17 percent). Most agencies addressed issues and outcomes that did not strictly fall under the typical definition of HTA but that increased the “contextualization” of their findings.

Conclusions:Our discussion highlights four paradoxes and reflects further on challenges raised by the coordination of HTA within large countries and among European states. This study concludes that HTA is being redefined in Canada as HTA agencies offer a more contextualized informational basis, an approach that may prove more compatible with the increased demand for HTA.
Factors influencing the publication of health research
Authors: Cronin Eugenia , Sheldon Trevor
Published: May 2008

Objectives:Assess the degree to which research project findings were published and explore factors that influenced publication.

Methods:Questionnaire to project leaders. Classification of publications and findings. Chi-squared; univariate and multivariate Cox regression analyses.

Results:Forty percent of projects published in peer-reviewed journal; highly statistically significant relationships between publication in peer-reviewed journals and (1) projects in Responsive/Fellowships streams (p=.045); and (2) projects awarded >£22,713 (p=.02); influence of study findings not statistically significant.

Conclusions:Funders should consider the significant number of studies that did not result in publication and the higher rate of publication in peer-reviewed journals from some programs.
Use of systematic reviews in the development of new provincial public health policies in Ontario
Authors: Dobbins Maureen , Thomas Helen , O'Brien Mary Ann , Duggan Melissa
Published: May 2008

Objectives: The study determined whether the results of recently completed systematic reviews evaluating the effectiveness of public health interventions were used in the development of new provincial policies for public health practice.

Methods: This telephone survey included all members from five review groups who updated the Ontario Mandatory Health Programs and Services guidelines for Public Health in 2000. Independent variables included characteristics of the systematic reviews, organization, and the individual. Outcomes included the use of the reviews in developing new policies and the extent to which the reviews led to new recommendations for practice. Descriptive summaries as well as multiple linear regression were conducted.

Results: Eighty-five percent of decision-makers agreed to participate in the study. Ninety-six percent of respondents reported that the systematic reviews played a part in developing the new guidelines, while 47 percent indicated that the reviews contributed a great deal to the development of new recommendations for practice. The multiple linear regression model explained 42 percent of the variation in use of the reviews for developing new recommendations for practice. Significant predictor variables included the importance of the reviews in comparison to other sources of information and relevance of the reviews to the policy decisions.

Conclusion: Public health decision-makers in Ontario have very positive perceptions of the usefulness of systematic reviews in policy development. Therefore, ongoing efforts to promote the usefulness and relevance of systematic reviews to public health decision-makers should remain a priority for health services researchers.
Major bleeding rates after prophylaxis against venous thromboembolism: Systematic review, meta-analysis, and cost implications
Authors: Muntz James , Scott David A , Lloyd Adam , Egger Matthias
Published: May 2008

Objectives: The frequency and consequences of major bleeding associated with anticoagulant prophylaxis for prevention of venous thromboembolism is examined.

Methods: We conducted a systematic review and meta-analysis of controlled trials that reported rates of major bleeding after pharmaceutical thromboprophylaxis in patients undergoing major orthopedic surgery. Thromboprophylactic agents were divided into four groups:warfarin/other coumarin derivatives (WARF), unfractionated heparin (UFH), low molecular weight heparin (LMWH), and pentasaccharide (PS). Meta-analysis was conducted comparing LMWH with each of WARF, UFH, and PS. The frequency of re-operation due to major bleeding was reviewed and combined with published costs to estimate the mean cost of managing major bleeding events in these patients.

Results: Twenty-one studies including 20,523 patients met inclusion criteria for the meta-analysis. No evidence of significant between-trial heterogeneity in risk ratios was found. Combined (fixed effects) relative risks (RR) of major bleeding compared with LMWH were WARF – RR 0.59 (95 percent confidence interval [CI], 0.44–0.80); UFH – RR 1.52 (95 percent CI, 1.04–2.23); PS – RR 1.52 (95 percent CI, 1.11–2.09). Seventy-one studies including 32,433 patients were included in the review of consequences of major bleeding. We estimated that the average cost of major bleeding is $113 per patient receiving thromboprophylaxis.

Conclusions: LMWH results in fewer major bleeding episodes than UFH and PS but more than WARF. These events are costly and clinically important.
Clinicians' assessments of practice guidelines in oncology: The CAPGO survey
Authors: Brouwers Melissa C. , Graham Ian D. , Hanna Steven E. , Cameron David A. , Browman George P.
Published: May 2008

Objectives: Promoting the adoption of clinical practice guidelines is a challenging task. Research shows that adopters' beliefs about guidelines and the process of their development are important predictors of guideline use. Our objective is to report on the development and refinement of an instrument designed to measure oncologists' assessments of guidelines in oncology.

Method: A theoretically derived instrument was drafted. Oncologists were asked to complete a questionnaire for each draft guideline they were asked to review. Factor analyses and multilevel modeling techniques were undertaken to explore the properties of the instrument and refine it.

Results: A total of 488 Ontario clinicians were sent 1,494 new questionnaires regarding 34 clinical practice guidelines produced between 1999 and 2002. A refined eighteen-item questionnaire with four stable factors that predicted 60 percent of the variance emerged. The factors are interpreted as guideline quality, applicability, acceptability, and comparative value. The four factors predicted oncologists' endorsements of draft guidelines and, with the exception of quality, predicted their intentions to use the guidelines. As expected, variation in the factor scores could be attributed more to the differences among the oncologist who completed the survey than to the differences among the guidelines themselves.

Conclusions:An instrument composed of four stable and theoretically relevant factors emerged. The findings support the hypothesis that beliefs about guideline attributes and development attributes relate to oncologists' endorsement of and intentions to use guidelines. Our next step is to link the responses of the survey with actual clinical behavior.
The importance of accounting for the uncertainty of published prognostic model estimates
Authors: Young Tracey A. , Thompson Simon
Published: May 2008

Objectives: Reported is the importance of properly reflecting uncertainty associated with prognostic model estimates when calculating the survival benefit of a treatment or technology, using liver transplantation as an example.

Methods: Monte Carlo simulation techniques were used to account for the uncertainty of prognostic model estimates using the standard errors of the regression coefficients and their correlations. These methods were applied to patients with primary biliary cirrhosis undergoing liver transplantation using a prognostic model from a historic cohort who did not undergo transplantation. The survival gain over 4 years from transplantation was estimated.

Results: Ignoring the uncertainty in the prognostic model, the estimated survival benefit of liver transplantation was 16.7 months (95 percent confidence interval [CI], 13.5 to 20.1), and was statistically significant (p<.001). After adjusting for model uncertainty using the standard errors of the regression coefficients, the estimated survival benefit was 17.5 months (95 percent CI, −3.9 to 38.5) and was no longer statistically significant. An additional adjustment for the correlation between regression coefficients widened the 95 percent confidence interval slightly: the estimated survival benefit was 17.0 months (95 percent CI: −4.6 to 38.6).

Conclusions: It is important that the precision of regression coefficients is available for users of published prognostic models. Ignoring this additional information substantially underestimates uncertainty, which can then impact misleadingly on policy decisions.
Consumer involvement in the health technology assessment program
Authors: Royle Jane , Oliver Sandy
Published: May 2008

Objectives: This study aims to describe a cycle of development leading to sustainable methods for involving consumers in the management of a program commissioning health technology assessment.

Methods: Staff time was dedicated to developing procedures for recruiting and briefing consumers to participate in prioritizing, commissioning, and reporting research. Resources and support were developed in light of early feedback from consumers and those working with them. These were piloted and amended before being used routinely.

Results: Over 4 years, procedures and resources have been developed to support six consumers attending seven to eight prioritization meetings a year; thirty to forty-five consumers each year commenting on research need for particular topics; thirty consumers a year commenting on research proposals, and twenty a year commenting on research reports. The procedures include clear job descriptions, induction and development days, clear briefing materials, payment for substantial tasks, and regularly seeking feedback to improve procedures.

Conclusions: Explicit, inclusive, and reproducible methods for supporting consumer involvement that satisfy National Health Service policy recommendations for involving consumers in research require dedicated staff time to support a cycle of organizational development.
Situation analysis of prenatal diagnosis technology utilization in China: Current situation, main issues, and policy implications
Authors: Chen Yingyao , Qian Xu , Tang Zhiliu , Banta H. David , Hu Fangfang , Cao Jianwen , Huang Jiayan , Wang Qian , Lv Jun , Ying Xianghua , Chen Jie
Published: May 2008

Objectives: The purpose of this study is to describe the situation with the distribution and utilization of prenatal diagnosis technology in China, to identify some important barriers to prenatal diagnosis use, and to suggest changes to improve the present situation.

Methods: The study uses cross-sectional surveys to capture quantitative data from both providers and consumers. Qualitative information based on focus group discussions is also presented.

Results: A mail survey of the provincial Bureaus of Health (BOHs) reveals that sixteen provincial prenatal diagnosis centers and twelve city level centers were accredited by the BOHs by July of 2001. These centers were located in thirteen provinces, of thirty in all of China. Of 147 selected institutions surveyed separately, 90.5 ercent offer ultrasound examination, 72.1 percent provide pathogen tests (mainly Toxoplasma, rubella virus, cytomegalovirus, and herpes simplex or TORCH), 57.1 percent do biochemical tests, 21.8 percent have genetic counseling, 13.6 percent do karyotype testing, 7.5 percent do enzymology testing, and 5.4 percent carry out molecular genetic testing. Chromosome diseases, congenital diseases, and several gene diseases are the target diseases. According to qualitative data, macromanagement for prenatal diagnosis, supplier provision of tests, and population demand are the main influences on prenatal diagnosis use.

Conclusions: From the quantitative and qualitative analysis, it is clear that the technology of prenatal diagnosis is not diffusing well throughout China and is apparently not appropriately used. The situation of prenatal diagnosis has implications for policy-makers, including identification of priorities, regulation of prenatal diagnosis, strategic planning, development of guidelines based on health technology assessment, and consumer orientation.
Costing day case anesthesia: obtaining accurate patient-based costs for adults and children
Authors: Elliott Rachel A. , Davies Linda M. , Payne Katherine , Moore Julia K. , Harper Nigel J. N.
Published: May 2008

Objectives: This study proposes the method requirements for a valid costing study in anesthesia to allow differences to be identified between treatments and uses these method requirements to design and conduct a robust costing study.

Methods: A prospective, patient-based costing study was carried out in adult and pediatric day surgery in the United Kingdom. The perspective was that of the National Health Service and the patient. Data were collected for each patient until 7 days after hospital discharge.

Results: Data were collected for 1,063 adults and 322 children undergoing day surgery between October 1999 and January 2001. Statistically significant differences were found only between variable costs, which accounted for 11.4 percent and 9.0 percent of adult and pediatric costs, respectively. There were no differences in length of stay, fixed costs, or semi-fixed costs. Differences were not found in total costs in adults but were found in children. By day 7, postdischarge primary and secondary care costs were not different between groups in either study. No differences were found in costs to patients or parents.

Conclusions: The use of prospective, patient-based cost data enabled the detection of differences in variable costs between difference anesthetic regimens in day surgery. The stochastic nature of the data provided a measure of variability around mean cost estimates. Practice patterns in the study reflected normal practice in the United Kingdom so the costing data have direct clinical relevance. The use of different anesthetic agents only affected variable costs and had no effect on larger cost drivers such as length of stay or staff input.
Pulsating travelling fronts: Asymptotics and homogenization regimes
Authors: EL SMAILY MOHAMMAD
Published: May 2008

This paper is concerned with some non-linear propagation phenomena for reaction–advection–diffusion equations with Kolmogrov–Petrovsky–Piskunov (KPP)-type non-linearities in general periodic domains or in infinite cylinders with oscillating boundaries. Having a variational formula for the minimal speed of propagation involving eigenvalue problems (proved in Berestycki, H., Hamel, F. & Nadirashvili, N. (2005) The speed of propagation for KPP type problems (periodic framework).J. Eur. Math. Soc.7, 173–213), we consider the minimal speed of propagation as a function of diffusion factors, reaction factors and periodicity parameters. There we study the limits, the asymptotic behaviours and the variations of the considered functions with respect to these parameters. One of the sections deals with homogenization problem as an application of the results in the previous sections in order to find the limit of the minimal speed when the periodicity cell is very small.
Is the “Perfect Fontan” operation routinely achievable in the modern era?
Authors: Kirklin James K. , Brown Robert N. , Bryant Ayesha S. , Naftel David C. , Colvin Edward V. , Bennett Pearce F. , Romp Robb L. , Johnson Walter H. , Lau Yung R. , McMahon William S. , Knott-Craig Christopher J. , Pacifico Albert D.
Published: May 2008

Objective

In 1990, Fontan, Kirklin, and colleagues published equations for survival after the so-called “Perfect Fontan” operation. After 1988, we evolved a protocol using an internal or external polytetraflouroethylene tube of 16 to 19 millimetres diameter placed from the inferior caval vein to either the right or left pulmonary artery along with a bidirectional cava-pulmonary connection. The objective of this study was to test the hypothesis that a “perfect” outcome is routinely achievable in the current era when using a standardized surgical procedure.

Methods

Between 1 January, 1988, and 12 December, 2005, 112 patients underwent the Fontan procedure using an internal or external polytetraflouroethylene tube plus a bidirectional cava-pulmonary connection, the latter usually having been constructed as a previous procedure. This constituted 45% of our overall experience in constructing the Fontan circulation between 1988 and 1996, and 96% of the experience between 1996 and 2005. Among all surviving patients, the median follow-up was 7.3 years. We calculated the expected survival for an optimal candidate, given from the initial equations, and compared this to our entire experience in constructing the Fontan circulation.

Results

An internal tube was utilized in 61 patients, 97% of whom were operated prior to 1998, and an external tube in 51 patients, the latter accounting for 95% of all operations since 1999. At 1, 5, 10 and 15 years, survival of the entire cohort receiving polytetraflouroethylene tubes is superimposable on the curve calculated for a “perfect” outcome. Freedom from replacement or revision of the tube was 97% at 10 years.

Conclusion

Using a standardized operative procedure, combining a bidirectional cavopulmonary connection with a polytetraflouroethylene tube placed from the inferior caval vein to the pulmonary arteries for nearly all patients with functionally univentricular hearts, early and late survival within the “perfect” outcome as predicted by the initial equations of Fontan and Kirklin is routinely achievable in the current era. The need for late revision or replacement of the tube is rare.
Prenatal diagnosis of topsy-turvy heart
Authors: Jaeggi Edgar , Chitayat David , Golding Fraser , Kim Peter , Yoo Shi-Joon
Published: May 2008

We describe two siblings of consanguineous parents with a prenatal diagnosis of a currently unique form of congenital cardiac disease characterized by superior-inferior atrial and ventricular arrangement, concordant atrioventricular and ventriculo-arterial connections with normal arterial relationships, and a bizarre topography of the ventricular outlets, with the arterial poles being displaced posterior-inferiorly within the thorax. The abnormally low position of the aortic arch resulted in elongation and stretching of the airways, with severe compression of the trachea and left main bronchus in the surviving sibling. The finding of the same rare abnormality in a son and a daughter born to consanguineous parents supports a single gene disorder with a recessive mode of inheritance.