GiViP: A Visual Profiler for Distributed Graph Processing Systems

Analyzing large-scale graphs provides valuable insights in different application scenarios. While many graph processing systems working on top of distributed infrastructures have been proposed to deal with big graphs, the tasks of profiling and debugging their massive computations remain time consuming and error-prone. This paper presents GiViP, a visual profiler for distributed graph processing systems based on a Pregel-like computation model. GiViP captures the huge amount of messages exchanged throughout a computation and provides an interactive user interface for the visual analysis of the collected data. We show how to take advantage of GiViP to detect anomalies related to the computation and to the infrastructure, such as slow computing units and anomalous message patterns.Comment: Appears in the Proceedings of the 25th International Symposium on Graph Drawing and Network Visualization (GD 2017

The EuroHeart Failure Survey programme—a survey on the quality of care among patients with heart failure in Europe Part 2: treatment

National surveys suggest that treatment of heart failure in daily practice differs from guidelines and is characterized by underuse of recommended medications. Accordingly, the Euro, Heart Failure Survey was conducted to ascertain how patients hospitalized for heart failure are managed in Europe and if national variations occur in the treatment of this condition. Methods The survey screened discharge summaries of 11 304 patients over a 6-week period in 115 hospitals from 24 countries belonging to the ESC to study their medical treatment. Results Diuretics (mainly loop diuretics) were prescribed in 86.9% followed by ACE inhibitors (61.8%), beta-blockers (36.9%), cardiac glycosides (35.7%), nitrates (32.1%), calcium. channel blockers (21.2%) and spironolactone (20.5%). 44.6% of the population used four or more different drugs. Only 17.2% were under the combination of diuretic, ACE inhibitors and beta-blockers. Important local variations were found in the rate of prescription of ACE inhibitors and particularly beta-blockers. Daily dosage of ACE inhibitors and particularly of beta-blockers was on average below the recommended target dose. Modelling-analysis of the prescription of treatments indicated that the aetiology of heart failure, age, co-morbid factors and type of hospital ward influenced the rate of prescription. Age 70 years, in patients with respiratory disease and increased in cardiology wards, in ischaemic heart failure and in mate subjects. Prescription of cardiac glycosides was significantly increased in patients with supraventricular tachycardia/atrial fibrillation. Finally, the rate of prescription of antithrombotic agents was increased in the presence of supraventricular arrhythmia, ischaemic heart disease, mate subjects but was decreased in patients over 70. Conclusion Our results suggest that the prescription of recommended medications including ACE inhibitors and beta-blockers remains limited and that the daily dosage remains tow, particularly for beta-blockers. The survey also identifies several important factors including age, gender, type of hospital ward, co morbid factors which influence the prescription of heart failure medication at discharge

Glucagon receptor gene mutations with hyperglucagonemia but without the glucagonoma syndrome

Pancreatic neoplasms producing exclusively glucagon associated with glucagon cell hyperplasia of the islets and not related to hereditary endocrine syndromes have been recently described. They represent a novel entity within the panel of non-syndromic disorders associated with hyperglucagonemia. This case report describes a 36-year-old female with a 10 years history of non-specific abdominal pain. No underlying cause was evident despite extensive diagnostic work-up. More recently she was diagnosed with gall bladder stones. Abdominal ultrasound, computerised tomography and magnetic resonance imaging revealed no pathologic findings apart from cholelithiasis. Endoscopic ultrasound revealed a 5.5 mm pancreatic lesion. Fine needle aspiration showed cells focally expressing chromogranin, suggestive but not diagnostic of a low grade neuroendocrine tumor. OctreoScan(®) was negative. Serum glucagon was elevated to 66 pmol/L (normal: 0-50 pmol/L). Other gut hormones, chromogranin A and chromogranin B were normal. Cholecystectomy and enucleation of the pancreatic lesion were undertaken. Postoperatively, abdominal symptoms resolved and serum glucagon dropped to 7 pmol/L. Although H and E staining confirmed normal pancreatic tissue, immunohistochemistry was initially thought to be suggestive of alpha cell hyperplasia. A count of glucagon positive cells from 5 islets, compared to 5 islets from 5 normal pancreata indicated that islet size and glucagon cell ratios were increased, however still within the wide range of normal physiological findings. Glucagon receptor gene (GCGR) sequencing revealed a heterozygous deletion, K349_G359del and 4 missense mutations. This case may potentially represent a progenitor stage of glucagon cell adenomatosis with hyperglucagonemia in the absence of glucagonoma syndrome. The identification of novel GCGR mutations suggests that these may represent the underlying cause of this condition

Estimating the number needed to treat from continuous outcomes in randomised controlled trials: methodological challenges and worked example using data from the UK Back Pain Exercise and Manipulation (BEAM) trial

Background Reporting numbers needed to treat (NNT) improves interpretability of trial results. It is unusual that continuous outcomes are converted to numbers of individual responders to treatment (i.e., those who reach a particular threshold of change); and deteriorations prevented are only rarely considered. We consider how numbers needed to treat can be derived from continuous outcomes; illustrated with a worked example showing the methods and challenges. Methods We used data from the UK BEAM trial (n = 1, 334) of physical treatments for back pain; originally reported as showing, at best, small to moderate benefits. Participants were randomised to receive 'best care' in general practice, the comparator treatment, or one of three manual and/or exercise treatments: 'best care' plus manipulation, exercise, or manipulation followed by exercise. We used established consensus thresholds for improvement in Roland-Morris disability questionnaire scores at three and twelve months to derive NNTs for improvements and for benefits (improvements gained+deteriorations prevented). Results At three months, NNT estimates ranged from 5.1 (95% CI 3.4 to 10.7) to 9.0 (5.0 to 45.5) for exercise, 5.0 (3.4 to 9.8) to 5.4 (3.8 to 9.9) for manipulation, and 3.3 (2.5 to 4.9) to 4.8 (3.5 to 7.8) for manipulation followed by exercise. Corresponding between-group mean differences in the Roland-Morris disability questionnaire were 1.6 (0.8 to 2.3), 1.4 (0.6 to 2.1), and 1.9 (1.2 to 2.6) points. Conclusion In contrast to small mean differences originally reported, NNTs were small and could be attractive to clinicians, patients, and purchasers. NNTs can aid the interpretation of results of trials using continuous outcomes. Where possible, these should be reported alongside mean differences. Challenges remain in calculating NNTs for some continuous outcomes

The EuroHeart Failure survey programme—a survey on the quality of care among patients with heart failure in Europe Part 1: patient characteristics and diagnosis

The European Society of Cardiology (ESC) has published guidelines for the investigation of patients with suspected heart failure and, if the diagnosis is proven, their subsequent management. Hospitalisation provides a key point of care at which time diagnosis and treatment may be refined to improve outcome for a group of patients with a high morbidity and mortality. However, little international data exists to describe the features and management of such patients. Accordingly, the EuroHeart Failure survey was conducted to ascertain if appropriate tests were being performed with which to confirm or refute a diagnosis of heart failure and how this influenced subsequent management. Methods The survey screened consecutive deaths and discharges during 2000-2001 predominantly from medical wards over a 6-week period in 115 hospitals from 24 countries belonging to the ESC, to identify patients with known or suspected heart failure. Results A total of 46,788 deaths and discharges were screened from which 11,327 (24%) patients were enrolled with suspected or confirmed heart failure. Forty-seven percent of those enrolled were women. Fifty-one percent of women and 30% of men were aged >75 years. Eighty-three percent of patients had a diagnosis of heart failure made on or prior to the index admission. Heart failure was the principal reason for admission in 40%. The great majority of patients (>90%) had had an ECG, chest X-ray, haemoglobin and electrolytes measured as recommended in ESC guidelines, but only 66% had ever had an echocardiogram. Left ventricular ejection fraction had been measured in 57% of men and 41% of women, usually by echocardiography (84%) and was <40% in 51% of men but only in 28% of women. Forty-five percent of women and 22% of men were reported to have normal left ventricular systolic function by qualitative echocardiographic assessment. A substantial proportion of patients had alternative explanations for heart failure other than left ventricular systolic or diastolic dysfunction, including valve disease. Within 12 weeks of discharge, 24% of patients had been readmitted. A total of 1408 of 10,434 (13.5%) patients died between admission and 12 weeks follow-up. Conclusions Known or suspected heart failure comprises a large proportion of admissions to medical wards and such patients are at high risk of early readmission and death. Many of the basic investigations recommended by the ESC were usually carried out, although it is not clear whether this was by design or part of a general routine for all patients being admitted regardless of diagnosis. The investigation most specific for patients with suspected heart failure (echocardiography) was performed less frequently, suggesting that the diagnosis of heart failure is still relatively neglected. Most men but a minority of women who underwent investigation of cardiac function had evidence of moderate or severe left ventricular dysfunction, the main target of current advances in the treatment of heart failure. Considerable diagnostic uncertainty remains for many patients with suspected heart failure, even after echocardiography, which must be resolved in order to target existing and new therapies and services effectively. (C) 2003 Published by Elsevier Science Ltd on behalf of The European Society of Cardiology

A framework for power analysis using a structural equation modelling procedure

BACKGROUND: This paper demonstrates how structural equation modelling (SEM) can be used as a tool to aid in carrying out power analyses. For many complex multivariate designs that are increasingly being employed, power analyses can be difficult to carry out, because the software available lacks sufficient flexibility. Satorra and Saris developed a method for estimating the power of the likelihood ratio test for structural equation models. Whilst the Satorra and Saris approach is familiar to researchers who use the structural equation modelling approach, it is less well known amongst other researchers. The SEM approach can be equivalent to other multivariate statistical tests, and therefore the Satorra and Saris approach to power analysis can be used. METHODS: The covariance matrix, along with a vector of means, relating to the alternative hypothesis is generated. This represents the hypothesised population effects. A model (representing the null hypothesis) is then tested in a structural equation model, using the population parameters as input. An analysis based on the chi-square of this model can provide estimates of the sample size required for different levels of power to reject the null hypothesis. CONCLUSIONS: The SEM based power analysis approach may prove useful for researchers designing research in the health and medical spheres

STARD for Abstracts: Essential items for reporting diagnostic accuracy studies in journal or conference abstracts

Many abstracts of diagnostic accuracy studies are currently insufficiently informative. We extended the STARD (Standards for Reporting Diagnostic Accuracy) statement by developing a list of essential items that authors should consider when reporting diagnostic accuracy studies in journal or conference abstracts. After a literature review of published guidance for reporting biomedical studies, we identified 39 items potentially relevant to report in an abstract. We then selected essential items through a two round web based survey among the 85 members of the STARD Group, followed by discussions within an executive committee. Seventy three STARD Group members responded (86%), with 100% completion rate. STARD for Abstracts is a list of 11 quintessential items, to be reported in every abstract of a diagnostic accuracy study. We provide examples of complete reporting, and developed template text for writing informative abstract

One More Awareness Gap? The Behaviour–Impact Gap Problem

Preceding research has made hardly any attempt to measure the ecological impacts of pro-environmental behaviour in an objective way. Those impacts were rather supposed or calculated. The research described herein scrutinized the ecological impact reductions achieved through pro-environmental behaviour and raised the question how much of a reduction in carbon footprint can be achieved through voluntary action without actually affecting the socio-economic determinants of life. A survey was carried out in order to measure the difference between the ecological footprint of “green” and “brown” consumers. No significant difference was found between the ecological footprints of the two groups—suggesting that individual pro-environmental attitudes and behaviour do not always reduce the environmental impacts of consumption. This finding resulted in the formulation of a new proposition called the BIG (behaviour–impact gap) problem, which is an interesting addition to research in the field of environmental awareness gaps

Mechanical Metamaterials with Negative Compressibility Transitions

When tensioned, ordinary materials expand along the direction of the applied force. Here, we explore network concepts to design metamaterials exhibiting negative compressibility transitions, during which a material undergoes contraction when tensioned (or expansion when pressured). Continuous contraction of a material in the same direction of an applied tension, and in response to this tension, is inherently unstable. The conceptually similar effect we demonstrate can be achieved, however, through destabilisations of (meta)stable equilibria of the constituents. These destabilisations give rise to a stress-induced solid-solid phase transition associated with a twisted hysteresis curve for the stress-strain relationship. The strain-driven counterpart of negative compressibility transitions is a force amplification phenomenon, where an increase in deformation induces a discontinuous increase in response force. We suggest that the proposed materials could be useful for the design of actuators, force amplifiers, micro-mechanical controls, and protective devices.Comment: Supplementary information available at http://www.nature.com/nmat/journal/v11/n7/abs/nmat3331.htm