pyCM: An open-source computational framework for residual stress analysis employing the Contour Method

The contour method for assessing residual stress is a widely accessible method in terms of the equipment required and experimental protocol. However, its application is hampered by the absence of a common computational framework to reconstruct the residual stress field and visualise the final result. In order to help regularise the analysis an open-source reconstruction package is presented: the Python Contour Method (pyCM). This package comprises a graphical user interface framework for the purposes for analysing and resolving stresses from experimental contour method data. The code requires no proprietary software and is expandable and fully transparent, enabling users to evaluate it and extend it to develop best practice. The framework is presented and compared against results stemming from a widely published edge-welded beam dataset produced as part of the EC 5th Framework ENPOWER project to highlight applicability

The global stock of research evidence relevant to health systems policymaking

Background: Policymakers and stakeholders need immediate access to many types of research evidence to make informed decisions about the full range of questions that may arise regarding health systems. Methods: We examined all types of research evidence about governance, financial and delivery arrangements, and implementation strategies within health systems contained in Health Systems Evidence (HSE) (http://www.healthsystemsevidence.org). The research evidence types include evidence briefs for policy, overviews of systematic reviews, systematic reviews of effects, systematic reviews addressing other questions, systematic reviews in progress, systematic reviews being planned, economic evaluations, and health reform and health system descriptions. Specifically, we describe their distribution across health system topics and domains, trends in their production over time, availability of supplemental content in various languages, and the extent to which they focus on low- and middle-income countries (LMICs), as well as (for systematic reviews) their methodological quality and the availability of user-friendly summaries. Results: As of July 2013, HSE contained 2,629 systematic reviews of effects (of which 501 are Cochrane reviews), 614 systematic reviews addressing other questions, 283 systematic reviews in progress, 186 systematic reviews being planned, 140 review-derived products (evidence briefs and overviews of systematic reviews), 1,669 economic evaluations, 1,092 health reform descriptions, and 209 health system descriptions. Most systematic reviews address topics related to delivery arrangements (n = 2,663) or implementation strategies (n = 1,653) with far fewer addressing financial (n = 241) or governance arrangements (n = 231). In addition, 2,928 systematic reviews have been quality appraised with moderate AMSTAR ratings found for reviews addressing governance (5.6/11), financial (5.9/11), and delivery (6.3/11) arrangements and implementation strategies (6.5/11); 1,075 systematic reviews have no independently produced user-friendly summary and only 737 systematic reviews have an LMIC focus. Literature searches for half of the systematic reviews (n = 1,584, 49%) were conducted within the last five years. Conclusions: Greater effort needs to focus on assessing whether the current distribution of systematic reviews corresponds to policymakers’ and stakeholders’ priorities, updating systematic reviews, increasing the quality of systematic reviews, and focusing on LMICs

Towards a better understanding of the nomenclature used in information-packaging efforts to support evidence-informed policymaking in low- and middle-income countries

Background: The growing recognition of the importance of concisely communicating research evidence and other policy-relevant information to policymakers has underpinned the development of several information-packaging efforts over the past decade. This has led to a wide variability in the types of documents produced, which is at best confusing and at worst discouraging for those they intend to reach. This paper has two main objectives: to develop a better understanding of the range of documents and document names used by the organizations preparing them; and to assess whether there are any consistencies in the characteristics of sampled documents across the names employed to label (in the title) or describe (in the document or website) them. Methods: We undertook a documentary analysis of web-published document series that are prepared by a variety of organizations with the primary intention of providing information to health systems policymakers and stakeholders, and addressing questions related to health policy and health systems with a focus on low- and middle-income countries. No time limit was set. Results: In total, 109 individual documents from 24 series produced by 16 different organizations were included. The name ‘policy brief/briefing’ was the most frequently used (39%) to label or describe a document, and was used in all eight broad content areas that we identified, even though they did not have obviously common traits among them. In terms of document characteristics, most documents (90%) used skimmable formats that are easy to read, with understandable, jargon-free, language (80%). Availability of information on the methods (47%) or the quality of the presented evidence (27%) was less common. One-third (32%) chose the topic based on an explicit process to assess the demand for information from policy makers and even fewer (19%) engaged with policymakers to discuss the content of these documents such as through merit review. Conclusions: This study highlights the need for organizations embarking on future information-packaging efforts to be more thoughtful when deciding how to name these documents and the need for greater transparency in describing their content, purpose and intended audience

Cost-utility of transcatheter aortic valve implantation for inoperable patients with severe aortic stenosis treated by medical management: a UK cost-utility analysis based on patient-level data from the ADVANCE study.

OBJECTIVE: To use patient-level data from the ADVANCE study to evaluate the cost-effectiveness of transcatheter aortic valve implantation (TAVI) compared to medical management (MM) in patients with severe aortic stenosis from the perspective of the UK NHS. METHODS: A published decision-analytic model was adapted to include information on TAVI from the ADVANCE study. Patient-level data informed the choice as well as the form of mathematical functions that were used to model all-cause mortality, health-related quality of life and hospitalisations. TAVI-related resource use protocols were based on the ADVANCE study. MM was modelled on publicly available information from the PARTNER-B study. The outcome measures were incremental cost-effectiveness ratios (ICERs) estimated at a range of time horizons with benefits expressed as quality-adjusted life-years (QALY). Extensive sensitivity/subgroup analyses were undertaken to explore the impact of uncertainty in key clinical areas. RESULTS: Using a 5-year time horizon, the ICER for the comparison of all ADVANCE to all PARTNER-B patients was £13 943 per QALY gained. For the subset of ADVANCE patients classified as high risk (Logistic EuroSCORE >20%) the ICER was £17 718 per QALY gained). The ICER was below £30 000 per QALY gained in all sensitivity analyses relating to choice of MM data source and alternative modelling approaches for key parameters. When the time horizon was extended to 10 years, all ICERs generated in all analyses were below £20 000 per QALY gained. CONCLUSION: TAVI is highly likely to be a cost-effective treatment for patients with severe aortic stenosis

Observed variability of the North Atlantic current in the Rockall Trough from four years of mooring measurements

The Rockall Trough is one of the main conduits for warm Atlantic Water to the Nordic Seas. Ocean heat anomalies, originating from the eastern subpolar gyre, are known to influence Arctic sea ice extent, marine ecosystems, and continental climate. Knowledge of the transport through this basin has previously been limited to estimates from hydrographic sections which cannot characterise the intra‐annual and multi‐annual variability. As part of the Overturning in the Subpolar North Atlantic Programme (OSNAP), a mooring array was deployed in the Rockall Trough in order to obtain the first continuous measurements of transport. Here, we define the methodology and the errors associated with estimating these transports. Results show a 4‐year mean northward transport of 6.6 Sv (1 Sv = 106 m3/s) by the North Atlantic Current (NAC) in the east and interior of the Rockall Trough (2014‐2018). A mean transport of ‐2.0 Sv (southward) is observed in the west of the basin, which could be part of a recirculation around the Rockall Plateau. The 90‐day low‐pass filtered transport shows large sub‐annual and inter‐annual variability (‐1.6 Sv to 9.1 Sv), mostly resulting from changes in the mid‐basin geostrophic transport. Satellite altimetry reveals the periods of low and high transport are associated with significant changes in the Rockall Trough circulation. There is a detectable seasonal signal, with the greatest transport in spring and autumn

Human Placental Arterial Distensibility, Birth Weight, and Body Size Are Positively Related to Fetal Homocysteine Concentration

Methionine demethylation during metabolism generates homocysteine (Hcy) and its remethylation requires folate and cobalamin. Elevated Hcy concentrations are associated with vascular-related complications of pregnancy, including increased vascular stiffness, predictive of clinical vascular disease. Maternal and fetal total Hcy (tHcy) concentrations are positively related, yet the influence of Hcy on fetoplacental vascular function in normal pregnancy has not been examined. We hypothesized that Hcy alters fetoplacental vascular characteristics with influences on fetal growth outcomes. We investigated (1) placental chorionic plate artery distensibility and neonatal blood pressure in relation to umbilical plasma tHcy; (2) relationships between cord venous (CV) and cord arterial (CA) plasma tHcy, folate, and cobalamin concentrations; and (3) tHcy associations with birth weight and anthropometric measurements of body size as indices of fetal growth in normal pregnancies with appropriate weight-for-gestational age newborns. Maternal plasma tHcy, folate, and cobalamin concentrations were consistent with published data. Placental chorionic plate artery distensibility index (β; measure of vessel stiffness) was inversely related to CA tHcy, yet neonatal blood pressure was not significantly affected. CV and CA tHcy concentrations were positively related and CV tHcy negatively related to CV cobalamin but not folate. CV tHcy concentration positively related to birth weight, corrected birth weight per-centile, length, head circumference, and mid-arm circumference of newborns. CV cobalamin was inversely related to fetal growth indices but not to folate concentration. Our study demonstrates a potential relationship between fetal tHcy and placental artery distensibility, placing clinical relevance to cobalamin in influencing Hcy concentration and maintaining low vascular resistance to facilitate nutrient exchange favorable to fetal growth

权重连接神经网络的光电实现

在Ｈｏｐｆｉｅｌｄ模型基础上，对具有权重连接的Ｈｏｐｆｉｅｌｄ模型引入连接权重矩阵，这样只要在Ｈｏｐｆｉｅｌｄ内容寻址记忆光电阵列前多加一个连接权重矩阵阵列，则得具有权重连接的神经网络模型的光电实现

Catheter-based intervention for symptomatic patient with severe mitral regurgitation and very poor left ventricular systolic function - Safe but no room for complacency

Many patients with left ventricular systolic dysfunction have concomitant mitral regurgitation (MR). Their symptoms and prognosis worsen with increasing severity of MR. Percutaneous MitraClip((R)) can be used safely to reduce the severity of MR even in patients with advanced heart failure and is associated with improved symptoms, quality of life and exercise tolerance. However, a few patients with very poor left ventricular systolic function may experience significant haemodynamic disturbance in the peri-procedural period. We present three such patients, highlighting some of the potential problems encountered and discuss their possible pathophysiological mechanisms and safety measures.published_or_final_versio

Processes, contexts, and rationale for disinvestment: a protocol for a critical interpretive synthesis

Background: Practical solutions are needed to support the appropriate use of available health system resources as countries are continually pressured to ‘do more with less’ in health care. Increasingly, health systems and organizations are exploring the reassessment of possibly obsolete, inefficient, or ineffective health system resources and potentially redirecting funds to those that are more effective and efficient. Such processes are often referred to as ‘disinvestment’. Our objective is to gain further understanding about: 1) whether how and under what conditions health systems decide to pursue disinvestment; 2) how health systems have chosen to undertake disinvestment; and 3) how health systems have implemented their disinvestment approach. Methods/Design We will use a critical interpretive synthesis (CIS) approach, to develop a theoretical framework based on insights drawn from a range of relevant sources. We will conduct systematic searches of databases as well as purposive searches to identify literature to fill conceptual gaps that may emerge during our inductive process of synthesis and analysis. Two independent reviewers will assess search results for relevance and conceptually map included references. We will include all empirical and non-empirical articles that focus on disinvestment at a system level. We will then extract key findings from a purposive sample of articles using frameworks related to government agendas, policy development and implementation, and health system contextual factors and then synthesize and integrate the findings to develop a framework about our core areas of interest. Lastly, we will convene a stakeholder dialogue with Canadian and international policymakers and other stakeholders to solicit targeted feedback about the framework (e.g., by identifying any gaps in the literature that we may want to revisit before finalizing it) and deliberating about barriers for developing and implementing approaches to disinvestment, strategies to address these barriers and about next steps that could be taken by different constituencies. Discussion Disinvestment is an emerging field and there is a need for evidence to inform the prioritization, development, and implementation of strategies in different contexts. Our CIS and the framework developed through it will support the actions of those involved in the prioritization, development, and implementation of disinvestment initiatives. Systematic review registration PROSPERO CRD42014013204 Electronic supplementary material The online version of this article (doi:10.1186/2046-4053-3-143) contains supplementary material, which is available to authorized users