Run Time Approximation of Non-blocking Service Rates for Streaming Systems

Stream processing is a compute paradigm that promises safe and efficient parallelism. Modern big-data problems are often well suited for stream processing's throughput-oriented nature. Realization of efficient stream processing requires monitoring and optimization of multiple communications links. Most techniques to optimize these links use queueing network models or network flow models, which require some idea of the actual execution rate of each independent compute kernel within the system. What we want to know is how fast can each kernel process data independent of other communicating kernels. This is known as the "service rate" of the kernel within the queueing literature. Current approaches to divining service rates are static. Modern workloads, however, are often dynamic. Shared cloud systems also present applications with highly dynamic execution environments (multiple users, hardware migration, etc.). It is therefore desirable to continuously re-tune an application during run time (online) in response to changing conditions. Our approach enables online service rate monitoring under most conditions, obviating the need for reliance on steady state predictions for what are probably non-steady state phenomena. First, some of the difficulties associated with online service rate determination are examined. Second, the algorithm to approximate the online non-blocking service rate is described. Lastly, the algorithm is implemented within the open source RaftLib framework for validation using a simple microbenchmark as well as two full streaming applications.Comment: technical repor

Asian gliriform origin for arctostylopid mammals

A

Persistent starspot signals on M dwarfs: multi-wavelength Doppler observations with the Habitable-zone Planet Finder and Keck/HIRES

Young, rapidly-rotating M dwarfs exhibit prominent starspots, which create quasiperiodic signals in their photometric and Doppler spectroscopic measurements. The periodic Doppler signals can mimic radial velocity (RV) changes expected from orbiting exoplanets. Exoplanets can be distinguished from activity-induced false positives by the chromaticity and long-term incoherence of starspot signals, but these qualities are poorly constrained for fully-convective M stars. Coherent photometric starspot signals on M dwarfs may persist for hundreds of rotations, and the wavelength dependence of starspot RV signals may not be consistent between stars due to differences in their magnetic fields and active regions. We obtained precise multi-wavelength RVs of four rapidly-rotating M dwarfs (AD Leo, G 227-22, GJ 1245B, GJ 3959) using the near-infrared (NIR) Habitable-zone Planet Finder, and the optical Keck/HIRES spectrometer. Our RVs are complemented by photometry from Kepler, TESS, and the Las Cumbres Observatory (LCO) network of telescopes. We found that all four stars exhibit large spot-induced Doppler signals at their rotation periods, and investigated the longevity and optical-to-NIR chromaticity for these signals. The phase curves remain coherent much longer than is typical for Sunlike stars. Their chromaticity varies, and one star (GJ 3959) exhibits optical and NIR RV modulation consistent in both phase and amplitude. In general, though, we find that the NIR amplitudes are lower than their optical counterparts. We conclude that starspot modulation for rapidly-rotating M stars frequently remains coherent for hundreds of stellar rotations, and gives rise to Doppler signals that, due to this coherence, may be mistaken for exoplanets.Comment: Accepted for publication in the Astrophysical Journa

Intelligent Cooperative Control Architecture: A Framework for Performance Improvement Using Safe Learning

Planning for multi-agent systems such as task assignment for teams of limited-fuel unmanned aerial vehicles (UAVs) is challenging due to uncertainties in the assumed models and the very large size of the planning space. Researchers have developed fast cooperative planners based on simple models (e.g., linear and deterministic dynamics), yet inaccuracies in assumed models will impact the resulting performance. Learning techniques are capable of adapting the model and providing better policies asymptotically compared to cooperative planners, yet they often violate the safety conditions of the system due to their exploratory nature. Moreover they frequently require an impractically large number of interactions to perform well. This paper introduces the intelligent Cooperative Control Architecture (iCCA) as a framework for combining cooperative planners and reinforcement learning techniques. iCCA improves the policy of the cooperative planner, while reduces the risk and sample complexity of the learner. Empirical results in gridworld and task assignment for fuel-limited UAV domains with problem sizes up to 9 billion state-action pairs verify the advantage of iCCA over pure learning and planning strategies

Long-term outcomes after stenting versus endarterectomy for treatment of symptomatic carotid stenosis: the International Carotid Stenting Study (ICSS) randomised trial.

BACKGROUND: Stenting is an alternative to endarterectomy for treatment of carotid artery stenosis, but long-term efficacy is uncertain. We report long-term data from the randomised International Carotid Stenting Study comparison of these treatments. METHODS: Patients with symptomatic carotid stenosis were randomly assigned 1:1 to open treatment with stenting or endarterectomy at 50 centres worldwide. Randomisation was computer generated centrally and allocated by telephone call or fax. Major outcomes were assessed by an independent endpoint committee unaware of treatment assignment. The primary endpoint was fatal or disabling stroke in any territory after randomisation to the end of follow-up. Analysis was by intention to treat ([ITT] all patients) and per protocol from 31 days after treatment (all patients in whom assigned treatment was completed). Functional ability was rated with the modified Rankin scale. This study is registered, number ISRCTN25337470. FINDINGS: 1713 patients were assigned to stenting (n=855) or endarterectomy (n=858) and followed up for a median of 4·2 years (IQR 3·0-5·2, maximum 10·0). Three patients withdrew immediately and, therefore, the ITT population comprised 1710 patients. The number of fatal or disabling strokes (52 vs 49) and cumulative 5-year risk did not differ significantly between the stenting and endarterectomy groups (6·4% vs 6·5%; hazard ratio [HR] 1·06, 95% CI 0·72-1·57, p=0·77). Any stroke was more frequent in the stenting group than in the endarterectomy group (119 vs 72 events; ITT population, 5-year cumulative risk 15·2% vs 9·4%, HR 1·71, 95% CI 1·28-2·30, p<0·001; per-protocol population, 5-year cumulative risk 8·9% vs 5·8%, 1·53, 1·02-2·31, p=0·04), but were mainly non-disabling strokes. The distribution of modified Rankin scale scores at 1 year, 5 years, or final follow-up did not differ significantly between treatment groups. INTERPRETATION: Long-term functional outcome and risk of fatal or disabling stroke are similar for stenting and endarterectomy for symptomatic carotid stenosis. FUNDING: Medical Research Council, Stroke Association, Sanofi-Synthélabo, European Union

Modular e-learning for a practical skill in vascular surgery

Introduction: Working Time Regulations in Europe allied with the endovascular revolution require vascular surgeons to be innovative in achieving competence during their training period. We evaluated the feasibility of eLearning to teach the use of OsiriX for sizing and planning endovascular aortic aneurysm repairs. Materials and Methods: Eight blended learning modules were constructed, consisting of instructional PDFs, demonstration videos, CT angiogram downloads for individual practice and online support forums. These were delivered online over a nine-week period. The learning material encompassed an introduction to the OsiriX interface, the basic skills to use OsiriX for sizing and planning of aneurysm repairs and advanced techniques for reconstruction and online communication relating to imaging. Results: The course was successfully delivered and produced positive feedback from registered users. A high rate of dropouts occurred during the early phase. The design and implementation of a fully web-based course by full time clinicians utilising multimedia and user forums to teach vascular surgeons the performance of a practical skill is feasible. Conclusions: A modular instructional course offered online by vascular surgeons is feasible in teaching clinicians the use of OsiriX for 3D reconstructions of CT angiograms of aortic aneurysms. Shortening course duration may improve compliance. The instructional model is effective and well received by compliant learners

Injection versus Decompression for Carpal Tunnel Syndrome-Pilot trial (INDICATE-P)-protocol for a randomised feasibility study.

Background Carpal tunnel syndrome (CTS) is the commonest peripheral nerve disorder in the UK, with over 52,996 carpal tunnel decompressions performed in 2011. By 2030, this figure is estimated to double. Whilst evidence supports conservative measures for mild symptoms, and early surgery for severe symptoms, controversy remains over the most appropriate management for patients that present with moderate disease, with regard to early surgery or late surgery following steroid injection. Injection versus Decompression for Carpal Tunnel Syndrome-Pilot trial (INDICATE-P) is a feasibility study for a multicentre, randomised controlled trial (INDICATE) to determine whether patients over the age of 18 with moderate CTS should undergo early surgical decompression of the median nerve or a single steroid injection (followed by later surgery if required). Methods/design INDICATE-P is a feasibility study for an open (non-blinded) randomised controlled pilot trial. Eligible participants will be adults with a clinical diagnosis of moderate CTS. This is defined as symptoms disturbing sleep or restricting activities of daily living or work, despite a 2-week trial of night splints. Participants will be randomised to one of two possible interventions: surgical decompression or a single steroid injection (followed by surgery later if required). Clinical outcome measures will be captured by postal questionnaire at 1, 3, 6 and 12 months post-randomisation. In order to improve the study design for the main INDICATE trial, feasibility data will also be collected to identify difficulties in recruitment and retention, to gain patient feedback on questionnaires and to confirm the suitability of the proposed outcome measures. Discussion The INDICATE-P feasibility study will contribute to the design and execution of the INDICATE trial, which will seek to assess the safety and effectiveness of two approaches to treatment for patients over 18 years of age with moderate CTS: early carpal tunnel decompression or a single steroid injection (followed by later surgery)

Nail bed INJury Assessment Pilot (NINJA-P) randomised controlled trial of replacing or discarding the nail plate after nail bed repair in children

Background Nail bed injuries are the most common hand injury in children. Surgical dogma is to replace the nail plate after repairing the nail bed. Recent evidence suggests this might increase infection rates and returns to clinic. The aim of this pilot randomised control trial was to inform the design and conduct of a definitive trial comparing replacing or discarding the nail plate after nail bed repair. Methods This study recruited participants from four hand units in the United Kingdom from April to July 2015. Participants were children under the age of 16 years with a nail bed injury requiring surgery. They were randomised to either having the nail plate replaced or discarded after nail bed repair. Additionally, follow-up method was also randomly allocated (postal versus clinic). We collected information on complications at two weeks and 30 days, and on nail plate appearance at four months using the Zook classification. Two possible approaches to follow-up were also piloted and compared. Results During the recruitment period there were 156 potentially eligible children. Sixty were randomised using remote web-based allocation in just over 3 months. By two weeks, there were two infections, both in children with replaced nail plates. The nail replaced group also experienced more complications. There was no evidence of a difference in return rates between postal and clinic follow-up. Conclusions This is the first pilot randomised control trial delivered using the Reconstructive Surgery Trials Network. Recruitment was rapid and nail bed repair appeared to have low complication and infection rates. The study findings have led to revision of the definitive trial protocol including the mode and timing of follow-up and modification of the Zook classification

Multiple novel prostate cancer susceptibility signals identified by fine-mapping of known risk loci among Europeans

Genome-wide association studies (GWAS) have identified numerous common prostate cancer (PrCa) susceptibility loci. We have fine-mapped 64 GWAS regions known at the conclusion of the iCOGS study using large-scale genotyping and imputation in 25 723 PrCa cases and 26 274 controls of European ancestry. We detected evidence for multiple independent signals at 16 regions, 12 of which contained additional newly identified significant associations. A single signal comprising a spectrum of correlated variation was observed at 39 regions; 35 of which are now described by a novel more significantly associated lead SNP, while the originally reported variant remained as the lead SNP only in 4 regions. We also confirmed two association signals in Europeans that had been previously reported only in East-Asian GWAS. Based on statistical evidence and linkage disequilibrium (LD) structure, we have curated and narrowed down the list of the most likely candidate causal variants for each region. Functional annotation using data from ENCODE filtered for PrCa cell lines and eQTL analysis demonstrated significant enrichment for overlap with bio-features within this set. By incorporating the novel risk variants identified here alongside the refined data for existing association signals, we estimate that these loci now explain ∼38.9% of the familial relative risk of PrCa, an 8.9% improvement over the previously reported GWAS tag SNPs. This suggests that a significant fraction of the heritability of PrCa may have been hidden during the discovery phase of GWAS, in particular due to the presence of multiple independent signals within the same regio

Cost-effectiveness of replacing versus discarding the nail in children with nail bed injury

Every year in the UK, around 10 000 children need to have operations to mend injuries to the bed of their fingernails. Currently, most children have their fingernail placed back on the injured nail bed after the operation. The NINJA trial found that children were slightly less likely to have an infection if the nail was thrown away rather than being put back, but the difference between groups was small and could have be due to chance. This study looked at whether replacing the nail is cost-effective compared with throwing it away. Using data from the NINJA trial, we compared costs, healthcare use, and quality of life and assessed the cost-effectiveness of replacing the nail. It was found that throwing the nail away after surgery would save the National Health Service (NHS) £75 (€85) per operation compared with placing the nail back on the nail bed. Changing clinical practice could save the NHS in England £720 000 (€819 000) per year