Nuclei: GPU-Accelerated Many-Core Network Coding

Abstract—While it is a well known result that network coding achieves optimal flow rates in multicast sessions, its potential for practical use has remained to be a question, due to its high computational complexity. Our previous work has attempted to design a hardware-accelerated and multi-threaded implementation of network coding to fully utilize multi-core CPUs, as well as SSE2 and AltiVec SIMD vector instructions on x86 and PowerPC processors. This paper represents another step forward, and presents the first attempt in the literature to maximize the performance of network coding by taking advantage of not only multi-core CPUs, but also potentially hundreds of computing cores in commodity off-the-shelf Graphics Processing Units (GPU). With GPU computing gaining momentum as a result of increased hardware capabilities and improved programmability, our work shows how the GPU, with a design involving thousands of lightweight threads, can boost network coding performance significantly. Many-core GPUs can be deployed as an attractive alternative and complementary solution to multi-core servers, by offering a better price/performance advantage. In fact, multicore CPUs and many-core GPUs can be deployed and used to perform network coding simultaneously, potentially useful in media streaming servers where hundreds of peers are served concurrently by these dedicated servers. In this paper, we present Nuclei, the design and implementation of GPU-based network coding. With Nuclei, only one mainstream NVidia 8800 GT GPU outperforms an 8-core Intel Xeon server in most test cases. A combined CPU-GPU encoding scenario achieves coding rates of up to 116 MB/second for a variety of coding settings, which is sufficient to saturate a Gigabit Ethernet interface. Index Terms—Network coding, Many-core GPU computing. I

Modeling the Effects of a Simple Immune System and Immunodeficiency on the Dynamics of Conjointly Growing Tumor and Normal Cells

In this paper, we develop a theoretical contribution towards the understanding of the complex behavior of conjoint tumor-normal cell growth under the influence of immuno-chemotheraputic agents under simple immune system response. In particular, we consider a core model for the interaction of tumor cells with the surrounding normal cells. We then add the effects of a simple immune system, and both immune-suppression factors and immuno-chemotherapeutic agents as well. Through a series of numerical simulations, we illustrate that the interdependency of tumor-normal cells, together with choice of drug and the nature of the immunodeficiency, leads to a variety of interesting patterns in the evolution of both the tumor and the normal cell populations

The evolving story of medical emergency teams in quality improvement

Adverse events affect approximately 3% to 12% of hospitalized patients. At least a third, but as many as half, of such events are considered preventable. Detection of these events requires investments of time and money. A report in a recent issue of Critical Care used the medical emergency team activation as a trigger to perform a prospective standardized evaluation of charts. The authors observed that roughly one fourth of calls were related to a preventable adverse event, which is comparable to the previous literature. However, while previous studies relied on retrospective chart reviews, this study introduced the novel element of real-time characterization of events by the team at the moment of consultation. This methodology captures important opportunities for improvements in local care at a rate far higher than routine incident-reporting systems, but without requiring substantial investments of additional resources. Academic centers are increasingly recognizing engagement in quality improvement as a distinct career pathway. Involving such physicians in medical emergency teams will likely facilitate the dual roles of these as a clinical outreach arm of the intensive care unit and in identifying problems in care and leading to strategies to reduce them

Using psychological theory to understand the clinical management of type 2 diabetes in Primary Care : a comparison across two European countries

Peer reviewedPublisher PD

Time to Update and Quantitative Changes in the Results of Cochrane Pregnancy and Childbirth Reviews

BACKGROUND: The recommended interval between updates for systematic reviews included in The Cochrane Library is 2 years. However, it is unclear whether this interval is always appropriate. Whereas excessive updating wastes time and resources, insufficient updating allows out-of-date or incomplete evidence to guide clinical decision-making. We set out to determine, for Cochrane pregnancy and childbirth reviews, the frequency of updates, factors associated with updating, and whether updating frequency was appropriate. METHODOLOGY/PRINCIPAL FINDINGS: Cochrane pregnancy and childbirth reviews published in Issue 3, 2007 of the Cochrane Database of Systematic Reviews were retrieved, and data were collected from their original and updated versions. Quantitative changes were determined for one of the primary outcomes (mortality, or the outcome of greatest clinical significance). Potential factors associated with time to update were assessed using the Cox proportional hazard model. Among the 101 reviews in our final sample, the median time before the first update was 3.3 years (95% CI 2.7-3.8). Only 32.7% had been updated within the recommended interval of 2 years. In 75.3% (76/101), a median of 3 new trials with a median of 576 additional participants were included in the updated versions. There were quantitative changes in 71% of the reviews that included new trials (54/76): the median change in effect size was 18.2%, and the median change in 95% CI width was 30.8%. Statistical significance changed in 18.5% (10/54) of these reviews, but conclusions were revised in only 3.7% (2/54). A shorter time to update was associated with the same original review team at updating. CONCLUSIONS/SIGNIFICANCE: Most reviews were updated less frequently than recommended by Cochrane policy, but few updates had revised conclusions. Prescribed time to update should be reconsidered to support improved decision-making while making efficient use of limited resources

Can patient decision aids help people make good decisions about participating in clinical trials? A study protocol

<p>Abstract</p> <p>Background</p> <p>Evidence shows that the standard process for obtaining informed consent in clinical trials can be inadequate, with study participants frequently not understanding even basic information fundamental to giving informed consent. Patient decision aids are effective decision support tools originally designed to help patients make difficult treatment or screening decisions. We propose that incorporating decision aids into the informed consent process will improve the extent to which participants make decisions that are informed and consistent with their preferences. A mixed methods study will test this proposal.</p> <p>Methods</p> <p>Phase one of this project will involve assessment of a stratified random sample of 50 consent documents from recently completed investigator-initiated clinical trials, according to existing standards for supporting good decision making. Phase two will involve interviews of a purposive sample of 50 trial participants (10 participants from each of five different clinical areas) about their experience of the informed consent process, and how it could be improved. In phase three, we will convert consent forms for two completed clinical trials into decision aids and pilot test these new tools using a user-centered design approach, an iterative development process commonly employed in computer usability literature. In phase four, we will conduct a pilot observational study comparing the new tools to standard consent forms, with potential recruits to two hypothetical clinical trials. Outcomes will include knowledge of key aspects of the decision, knowledge of the probabilities of different outcomes, decisional conflict, the hypothetical participation decision, and qualitative impressions of the experience.</p> <p>Discussion</p> <p>This work will provide initial evidence about whether a patient decision aid can improve the informed consent process. The larger goal of this work is to examine whether study recruitment can be improved from (barely) informed consent based on disclosure-oriented documents, towards a process of high-quality participant decision-making.</p

The research output on interventions for the behavioural risk factors alcohol & drug use and dietary risk is not related to their respective burden of ill health in countries at differing World Bank income levels

Background: Alcohol and drug use (A&D) and dietary risks are two increasingly important risk factors. This study examines whether there is a relationship between the burden of these risk factors in countries of specific income bands as defined by the World Bank, and the number of primary studies included in Cochrane Systematic Reviews (CSRs) conducted in those countries. Methods: Data was extracted from primary studies included in CSRs assessing two risk factors as outcomes. For each risk factor, data was obtained on its overall burden in disability-adjusted life years (DALYs) by World Bank Income Levels and examined for a link between DALYs, the number of primary studies and participants. Results: A total of 1601 studies from 95 CSRs were included. Only 18.3% of the global burden for A&D is in high income-countries (HICs) but they produced 90.5% of primary studies and include 99.5% of participants. Only 14.2% of the dietary risk burden is in HICs but they produced 80.5% of primary studies and included 98.1% of participants. Conclusions: This study demonstrates the unequal output of research heavily weighted towards HICs. More initiatives with informed contextual understanding are required to address this inequality and promote health research in low and middle-income countries

Identifying adverse events: reflections on an imperfect gold standard after 20 years of patient safety research

Analysis and support of clinical decision makin