Garbage collection auto-tuning for Java MapReduce on Multi-Cores

MapReduce has been widely accepted as a simple programming pattern that can form the basis for efficient, large-scale, distributed data processing. The success of the MapReduce pattern has led to a variety of implementations for different computational scenarios. In this paper we present MRJ, a MapReduce Java framework for multi-core architectures. We evaluate its scalability on a four-core, hyperthreaded Intel Core i7 processor, using a set of standard MapReduce benchmarks. We investigate the significant impact that Java runtime garbage collection has on the performance and scalability of MRJ. We propose the use of memory management auto-tuning techniques based on machine learning. With our auto-tuning approach, we are able to achieve MRJ performance within 10% of optimal on 75% of our benchmark tests

Understanding the influences on successful quality improvement in emergency general surgery: learning from the RCS Chole-QuIC project

Abstract: Background: Acute gallstone disease is the highest volume Emergency General Surgical presentation in the UK. Recent data indicate wide variations in the quality of care provided across the country, with national guidance for care delivery not implemented in most UK hospitals. Against this backdrop, the Royal College of Surgeons of England set up a 13-hospital quality improvement collaborative (Chole-QuIC) to support clinical teams to reduce time to surgery for patients with acute gallstone disease requiring emergency cholecystectomy. Methods: Prospective, mixed-methods process evaluation to answer the following: (1) how was the collaborative delivered by the faculty and received, understood and enacted by the participants; (2) what influenced teams’ ability to improve care for patients requiring emergency cholecystectomy? We collected and analysed a range of data including field notes, ethnographic observations of meetings, and project documentation. Analysis was based on the framework approach, informed by Normalisation Process Theory, and involved the creation of comparative case studies based on hospital performance during the project. Results: Chole-QuIC was delivered as planned and was well received and understood by participants. Four hospitals were identified as highly successful, based upon a substantial increase in the number of patients having surgery in line with national guidance. Conversely, four hospitals were identified as challenged, achieving no significant improvement. The comparative analysis indicate that six inter-related influences appeared most associated with improvement: (1) achieving clarity of purpose amongst site leads and key stakeholders; (2) capacity to lead and effective project support; (3) ideas to action; (4) learning from own and others’ experience; (5) creating additional capacity to do emergency cholecystectomies; and (6) coordinating/managing the patient pathway. Conclusion: Collaborative-based quality improvement is a viable strategy for emergency surgery but success requires the deployment of effective clinical strategies in conjunction with improvement strategies. In particular, achieving clarity of purpose about proposed changes amongst key stakeholders was a vital precursor to improvement, enabling the creation of additional surgical capacity and new pathways to be implemented effectively. Protected time, testing ideas, and the ability to learn quickly from data and experience were associated with greater impact within this cohort

Permeation of chlorinated hydrocarbons through nylon 6/ethylene-propylene rubber blends

SCOPUS: ar.jFLWINinfo:eu-repo/semantics/publishe

Gender differences in the prevalence of coronary artery tortuosity and its association with coronary artery disease

Little is known about the significance of severe coronary tortuosity (SCT) despite it being a relatively common finding on coronary angiography. We examined whether the presence of tortuosity was influenced by gender or cardiac risk factors. We examined 870 patients (Men = 589, Women = 281) who presented to Westmead Hospital, Sydney, Australia for invasive coronary angiography for the assessment of chest pain due to suspected CAD. Female gender and age were significantly associated with SCT (p < 0.001 for age) with 45.2% of women having SCT as opposed to 19.7% of men (p < 0.001). Men with SCT had lower Extent scores only compared than those without tortuosity (22.4 vs. 32.4, p = 0.003). However, women with SCT had less severe coronary artery disease than those with no SCT as measured by both the Extent score (12.4 vs. 19.1, p = 0.03) and Gensini score (10.4 vs. 15.5, p = 0.02). There is a significant relationship between coronary artery tortuosity and gender. Women with severe tortuosity are more likely to have normal coronary arteries or less severe disease than men despite presenting with chest pain

Gender differences in the prevalence of coronary artery tortuosity and its association with coronary artery disease

Background: Little is known about the significance of severe coronary tortuosity (SCT) despite it being a relatively common finding on coronary angiography. We examined whether the presence of tortuosity was influenced by gender or cardiac risk factors. Methods and results: We examined 870 patients (Men = 589, Women = 281) who presented to Westmead Hospital, Sydney, Australia for invasive coronary angiography for the assessment of chest pain due to suspected CAD. Female gender and age were significantly associated with SCT (p < 0.001 for age) with 45.2% of women having SCT as opposed to 19.7% of men (p < 0.001). Men with SCT had lower Extent scores only compared than those without tortuosity (22.4 vs. 32.4, p = 0.003). However, women with SCT had less severe coronary artery disease than those with no SCT as measured by both the Extent score (12.4 vs. 19.1, p = 0.03) and Gensini score (10.4 vs. 15.5, p = 0.02). Conclusion: There is a significant relationship between coronary artery tortuosity and gender. Women with severe tortuosity are more likely to have normal coronary arteries or less severe disease than men despite presenting with chest pain

Prediction of Coronary Artery Disease Extent and Severity Using Pulse Wave Velocity

<div><p>Background</p><p>Pulse-wave velocity (PWV) measures aortic stiffness. It is an independent predictor of cardiovascular events and mortality, yet there is paucity in the literature on its association with the severity and extent of coronary artery disease (CAD).</p><p>Methods</p><p>To examine the utility of PWV in predicting CAD burden in men and women the PWV was determined in 344 patients (Men = 266, Women = 78) presenting for invasive coronary angiography for the assessment of suspected CAD. Pearson correlations and multivariate analysis were used to evaluate the relationship between these coronary scores, PWV and traditional cardiovascular risk factors.</p><p>Results</p><p>Compared to men, women with chest pain had lower mean Extent scores (19.2 vs. 35.6; p = 0.0001) and Gensini scores (23.6 vs. 41.9; p = 0.0001). PWV was similar between men and women (12.35 ± 3.74 vs. 12.43 ± 4.58; p = 0.88) and correlated with Extent score (r = 0.21, p = 0.0001) but not Gensini or vessel score (r = 0.03, p = 0.64 and r = 0.06, p = 0.26, respectively). PWV was associated with Extent score in men (B = 2.25 ± 0.78, p = 0.004 for men and B = 1.50 ± 0.88, p = 0.09 for women). It was not a predictor of Gensini score (B = -0.10, P = 0.90).</p><p>Conclusion</p><p>PWV correlates with the extent of CAD, as measured by the ‘Extent’ score in men more than women. However, it does not correlate with the severity of obstructive CAD in either gender.</p></div

Average Extent score for men and women with Pulse-wave velocity <10 m/s and ≥10 m/s.

<p>Average Extent score for men and women with Pulse-wave velocity <10 m/s and ≥10 m/s.</p

The relationship of pulse-wave velocity (PWV) with Extent and Gensini score in men (A) and women (B) using a univariate linear regression analysis.

<p><i>Caption</i>: Solid line = regression line, dotted line = 95% confidence interval. The Δβ represents the change in value of the Extent or Gensini score with every 1 m/s increase in the PWV result. Significant dependent correlations have p < 0.05. PWV, pulse-wave velocity.</p