The End of a Myth: Distributed Transactions Can Scale

The common wisdom is that distributed transactions do not scale. But what if distributed transactions could be made scalable using the next generation of networks and a redesign of distributed databases? There would be no need for developers anymore to worry about co-partitioning schemes to achieve decent performance. Application development would become easier as data placement would no longer determine how scalable an application is. Hardware provisioning would be simplified as the system administrator can expect a linear scale-out when adding more machines rather than some complex sub-linear function, which is highly application specific. In this paper, we present the design of our novel scalable database system NAM-DB and show that distributed transactions with the very common Snapshot Isolation guarantee can indeed scale using the next generation of RDMA-enabled network technology without any inherent bottlenecks. Our experiments with the TPC-C benchmark show that our system scales linearly to over 6.5 million new-order (14.5 million total) distributed transactions per second on 56 machines.Comment: 12 page

Non-perturbative improvement of the vector current in Wilson lattice QCD

Many observables of interest in lattice QCD are extracted from correlation functions involving the vector current. If Wilson fermions are used, it is therefore of practical importance that, besides the action, the current be O($a$) improved in order to remove the leading discretization errors from the observables. Here we introduce and apply a new method to determine the improvement coefficient for the two most widely used discretizations of the current.Comment: 12 pages, 5 figure

Taming systems to create enabling environments for HCV treatment: negotiating trust in the drug and alcohol setting.

HCV (hepatitis C) treatment uptake among the population most affected - people who inject drugs - is suboptimal. Hospital based treatment provision is one evidenced barrier to HCV treatment uptake. In response, HCV treatment is increasingly located in treatment settings seen as more amenable to people who inject drugs, such as drug and alcohol services. We explored the accessibility of HCV treatment provision at two such partnerships. Data collection comprised qualitative interviews collected in 2011 and 2012 with 35 service users and 14 service providers of HCV treatment in London, United Kingdom. We draw here primarily on thematic analyses of service provider accounts, yet narratives relating to trust and environment emerged unsolicited in both user and provider accounts of negotiated HCV treatment access. A key theme in service provider accounts were strategies they deployed to 'tame' the treatment system so as to create an 'enabling environment' of care, in which trust was a critical feature. This 'taming' of the system was enacted through practices of 'negotiated flexibility', including in relation to appointments, eligibility, and phlebotomy. Service user accounts accentuated familiar environments and known health providers as those most trusted, and the potentially stigmatising effects of negotiating treatment in unfamiliar territory, especially hospital settings. Whilst noting the effects of provider strategies to negotiate flexibility on behalf of would-be patients seeking treatment, we conclude by noting the limits of trust relations in settings of constrained choice

WormBase: A modern Model Organism Information Resource

WormBase (https://wormbase.org/) is a mature Model Organism Information Resource supporting researchers using the nematode Caenorhabditis elegans as a model system for studies across a broad range of basic biological processes. Toward this mission, WormBase efforts are arranged in three primary facets: curation, user interface and architecture. In this update, we describe progress in each of these three areas. In particular, we discuss the status of literature curation and recently added data, detail new features of the web interface and options for users wishing to conduct data mining workflows, and discuss our efforts to build a robust and scalable architecture by leveraging commercial cloud offerings. We conclude with a description of WormBase\u27s role as a founding member of the nascent Alliance of Genome Resources

Mechanism of ferroelectric instabilities in non d^0 perovskites: LaCrO_3 versus CaMnO_3

The incompatibility of partial d occupation on the perovskite B-site with the standard charge transfer mechanism for ferroelectricity has been a central paradigm in multiferroics research. Nevertheless, it was recently shown by density functional theory calculations that CaMnO_3 exhibits a polar instability that even dominates over the octahedral tilting for slightly enlarged unit cell volume. Here, we present similar calculations for LaCrO_3, which has the same d^3 B-site electron configuration as CaMnO_3. We find that LaCrO_3 exhibits a very similar, albeit much weaker, polar instability as CaMnO_3. In addition, while the Born effective charge (BEC) of the Mn^{4+} cation in CaMnO_3 is highly anomalous, the BEC of Cr^{3+} in LaCrO_3 is only slightly enhanced. By decomposing the BECs into contributions of individual Wannier functions we show that the ferroelectric instabilities in both systems can be understood in terms of charge transfer between TM d and O p states, analogously to the standard d^0 perovskite ferroelectrics.Comment: 6 pages, 4 figures, 2 table

Frequency-splitting estimators of single-propagator traces

Single-propagator traces are the most elementary fermion Wick contractions which occur in numerical lattice QCD, and are usually computed by introducing random-noise estimators to profit from volume averaging. The additional contribution to the variance induced by the random noise is typically orders of magnitude larger than the one due to the gauge field. We propose a new family of stochastic estimators of single-propagator traces built upon a frequency splitting combined with a hopping expansion of the quark propagator, and test their efficiency in two-flavour QCD with pions as light as 190 MeV. Depending on the fermion bilinear considered, the cost of computing these diagrams is reduced by one to two orders of magnitude or more with respect to standard random-noise estimators. As two concrete examples of physics applications, we compute the disconnected contributions to correlation functions of two vector currents in the isosinglet omega channel and to the hadronic vacuum polarization relevant for the muon anomalous magnetic moment. In both cases, estimators with variances dominated by the gauge noise are computed with a modest numerical effort. Theory suggests large gains for disconnected three and higher point correlation functions as well. The frequency-splitting estimators and their split-even components are directly applicable to the newly proposed multi-level integration in the presence of fermions.Comment: 26 pages, 8 figures, LaTe

SUSY Production Cross Sections

We summarize the status of next-to-leading order perturbative quantum chromodynamics (pQCD) calculations of the cross sections for the production of squarks, gluinos, neutralinos, charginos, and sleptons as a function of the produced sparticle masses in proton-antiproton collisions at the hadronic center-of-mass energy 2 TeV.Comment: 7 pages, latex, plus one .eps figure; subgroup summary for the SUGRA working group of the Fermilab workshop Physics at Run II -- Supersymmetry/Higg

Laminitis: risk factors and outcome in a group of Danish horses

Reasons for performing study: Recent systematic reviews have highlighted the lack of quality information with respect to the epidemiology of equine laminitis. Objectives: To identify in Denmark the risk factors for new (i.e. not believed to have suffered from laminitis previously) cases of laminitis (NL) and to look at the outcome and incidence of repeated episodes of laminitis in these animals as well as those which had previously suffered an episode of laminitis (i.e. chronic cases) over the following 12 months. Methods: Information was obtained from 110 veterinary diagnosed cases of laminitis (69 new and 41 chronic) and 80 control animals (the next non-laminitic horse/pony seen by that participating practice). All animals were followed for up to one year. Univariable and multivariable conditional logistic regression was conducted for the NL case control pairs. Variables were retained within the final multivariable models if the likelihood ratio p-value was < 0.05. Results: There was no association between sex or gender and laminitis. A recent change of grass, being on what was considered high quality grass and being a cold-blooded type, <149cm ( i.e. Shetland, Fell, Welsh, or Dartmoor pony, Icelandic horse, Norwegian fjords, or a mix of these breeds) were all significant risk factors for laminitis. Although cresty neck score (CNS), and body condition Score (BCS), were significantly associated with NL at the univariable screening stage, they were found to be confounders of breed and each other during the multivariable model building process. Other factors such as weight, and estimated starch intake were not found to be significant .Thirty three percent of all the laminitis cases had been humanely destroyed within 12 months of diagnosis, mainly for laminitis associated reasons, compared with only 7.5% of the controls (none for laminitis associated reasons). Conclusions: and potential Relevance: This study confirms the importance of grass turn out and breed on laminitis risk. Horses in work at the time of diagnosis as well as those diagnosed in the winter and spring were more likely to be humanely destroyed within the next 12 months than those not in work or diagnosed in the autumn and summer