Per-Flow State Management Technique for High-Speed Networks

Flow processing is a fundamental element of stateful traffic classification and it has been recognized as an essential factor for delivering today’s application-aware network operations and security services. The basic function within a flow processing engine is to search and maintain a flow table, create new flow entries if no entry matches and associate each entry with flow states and actions for future queries. Network state information on a per-flow basis must be managed in an efficient way to enable Ethernet frame transmissions at 40 Gbit/s (Gbps) and 100 Gbps in the near future. This paper presents a hardware solution of flow state management for implementing large-scale flow tables on popular computer memories using DDR3 SDRAMs. Working with a dedicated flow lookup table at over 90 million lookups per second, the proposed system is able to manage 512-bit state information at run time.

UK publicly funded Clinical Trials Units supported a controlled access approach to share individual participant data but highlighted concerns

OBJECTIVES: Evaluate current data sharing activities of UK publicly funded Clinical Trial Units (CTUs) and identify good practices and barriers.

STUDY DESIGN AND SETTING: Web-based survey of Directors of 45 UK Clinical Research Collaboration (UKCRC)-registered CTUs.

RESULTS: Twenty-three (51%) CTUs responded: Five (22%) of these had an established data sharing policy and eight (35%) specifically requested consent to use patient data beyond the scope of the original trial. Fifteen (65%) CTUs had received requests for data, and seven (30%) had made external requests for data in the previous 12 months. CTUs supported the need for increased data sharing activities although concerns were raised about patient identification, misuse of data, and financial burden. Custodianship of clinical trial data and requirements for a CTU to align its policy to their parent institutes were also raised. No CTUs supported the use of an open access model for data sharing.

CONCLUSION: There is support within the publicly funded UKCRC-registered CTUs for data sharing, but many perceived barriers remain. CTUs are currently using a variety of approaches and procedures for sharing data. This survey has informed further work, including development of guidance for publicly funded CTUs, to promote good practice and facilitate data sharing.

ArnT proteins that catalyse the glycosylation of lipopolysaccharide share common features with bacterial N-oligosaccharyltransferases

ArnT is a glycosyltransferase that catalyses the addition of 4-amino-4-deoxy-L-arabinose (L-Ara4N) to the lipid A moiety of the lipopolysaccharide. This is a critical modification enabling bacteria to resist killing by antimicrobial peptides. ArnT is an integral inner membrane protein consisting of 13 predicted transmembrane helices and a large periplasmic C-terminal domain. We report here the identification of a functional motif with a canonical consensus sequence DEXRYAX(5)MX(3)GXWX(9)YFEKPX(4)W spanning the first periplasmic loop, which is highly conserved in all ArnT proteins examined. Site-directed mutagenesis demonstrated the contribution of this motif in ArnT function, suggesting that these proteins have a common mechanism. We also demonstrate that the Burkholderia cenocepacia and Salmonella enterica serovar Typhimurium ArnT C-terminal domain is required for polymyxin B resistance in vivo. Deletion of the C-terminal domain in B. cenocepacia ArnT resulted in a protein with significantly reduced in vitro binding to a lipid A fluorescent substrate and unable to catalyse lipid A modification with L-Ara4N. An in silico predicted structural model of ArnT strongly resembled the tertiary structure of Campylobacter lari PglB, a bacterial oligosaccharyltransferase involved in protein N-glycosylation. Therefore, distantly related oligosaccharyltransferases from ArnT and PglB families operating on lipid and polypeptide substrates, respectively, share unexpected structural similarity that could not be predicted from direct amino acid sequence comparisons. We propose that lipid A and protein glycosylation enzymes share a conserved catalytic mechanism despite their evolutionary divergence.

Sharing services, saving money? Five risks to cost saving when organizations share administrative services

Shared services are a popular reform for governments under financial pressure. The hope is to reduce overheads and increase efficiency by providing support services like HR, finance and procurement once to multiple agencies. Drawing on insights from organization theory and political science, we identify five risks that shared services won’t live up to current expectations. We illustrate each with empirical evidence from the UK, Ireland and further afield, and conclude with suggestions on how to manage these risks.

Can publicly available webcameras and mechanical Turks be used to evaluate physical activity policy and built environment change?

Introduction: Fewer than 50% of adults and 40% of youth meet US CDC guidelines for physical activity (PA) with the built environment (BE) a culprit for limited PA. A challenge in evaluating policy and BE change is the forethought to capture a priori PA behaviors and the ability to eliminate bias in post-change environments. The present objective was to analyze existing public data feeds to quantify effectiveness of BE interventions. The Archive of Many Outdoor Scenes (AMOS) has collected 135 million images of outdoor environments from 12,000 webcams since 2006. Many of these environments have experienced BE change. Methods: One example of BE change is the addition of protected bike lanes and a bike share program in Washington, DC.Weselected an AMOS webcam that captured this change. AMOS captures a photograph from eachwebcamevery half hour.AMOScaptured the 120 webcam photographs between 0700 and 1900 during the first work week of June 2009 and the 120 photographs from the same week in 2010. We used the Amazon Mechanical Turk (MTurk) website to crowd-source the image annotation. MTurk workers were paid US$0.01 to mark each pedestrian, cyclist and vehicle in a photograph. Each image was coded 5 unique times (n=1200). The data, counts of transportation mode, was downloaded to SPSS for analysis. Results: The number of cyclists per scene increased four-fold between 2009 and 2010 (F=36.72, p=0.002). There was no significant increase in pedestrians between the two years, however there was a significant increase in number of vehicles per scene (F=16.81, p