Evolving database systems : a persistent view

Submitted to POS7 This work was supported in St Andrews by EPSRC Grant GR/J67611 "Delivering the Benefits of Persistence"Orthogonal persistence ensures that information will exist for as long as it is useful, for which it must have the ability to evolve with the growing needs of the application systems that use it. This may involve evolution of the data, meta-data, programs and applications, as well as the users' perception of what the information models. The need for evolution has been well recognised in the traditional (data processing) database community and the cost of failing to evolve can be gauged by the resources being invested in interfacing with legacy systems. Zdonik has identified new classes of application, such as scientific, financial and hypermedia, that require new approaches to evolution. These applications are characterised by their need to store large amounts of data whose structure must evolve as it is discovered by the applications that use it. This requires that the data be mapped dynamically to an evolving schema. Here, we discuss the problems of evolution in these new classes of application within an orthogonally persistent environment and outline some approaches to these problems.Postprin

Oocyte cryopreservation as an adjunct to the assisted reproductive technologies

The document attached has been archived with permission from the editor of the Medical Journal of Australia. An external link to the publisher’s copy is included. See page 2 of PDF for this item.Keith L Harrison, Michelle T Lane, Jeremy C Osborn, Christine A Kirby, Regan Jeffrey, John H Esler and David Mollo

Linguistic Reflection in Java

Reflective systems allow their own structures to be altered from within. Here we are concerned with a style of reflection, called linguistic reflection, which is the ability of a running program to generate new program fragments and to integrate these into its own execution. In particular we describe how this kind of reflection may be provided in the compiler-based, strongly typed object-oriented programming language Java. The advantages of the programming technique include attaining high levels of genericity and accommodating system evolution. These advantages are illustrated by an example taken from persistent programming which shows how linguistic reflection allows functionality (program code) to be generated on demand (Just-In-Time) from a generic specification and integrated into the evolving running program. The technique is evaluated against alternative implementation approaches with respect to efficiency, safety and ease of use.Comment: 25 pages. Source code for examples at http://www-ppg.dcs.st-and.ac.uk/Java/ReflectionExample/ Dynamic compilation package at http://www-ppg.dcs.st-and.ac.uk/Java/DynamicCompilation

Which lipid measurement should we monitor? An analysis of the LIPID study

OBJECTIVES: To evaluate the optimal lipid to measure in monitoring patients, we assessed three factors that influence the choice of monitoring tests: (1) clinical validity; (2) responsiveness to therapy changes and (3) the size of the long-term ‘signal-to-noise’ ratio. DESIGN: Longitudinal analyses of repeated lipid measurement over 5 years. SETTING: Subsidiary analysis of a Long-Term Intervention with Pravastatin in Ischaemic Disease (LIPID) study—a clinical trial in Australia, New Zealand and Finland. PARTICIPANTS: 9014 patients aged 31–75 years with previous acute coronary syndromes. INTERVENTIONS: Patients were randomly assigned to 40 mg daily pravastatin or placebo. PRIMARY AND SECONDARY OUTCOME MEASURES: We used data on serial lipid measurements—at randomisation, 6 months and 12 months, and then annually to 5 years—of total cholesterol; low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol and their ratios; triglycerides; and apolipoproteins A and B and their ratio and their ability to predict coronary events. RESULTS: All the lipid measures were statistically significantly associated with future coronary events, but the associations between each of the three ratio measures (total or LDL cholesterol to HDL cholesterol, and apolipoprotein B to apolipoprotein A1) and the time to a coronary event were better than those for any of the single lipid measures. The two cholesterol ratios also ranked highly for the long-term signal-to-noise ratios. However, LDL cholesterol and non-HDL cholesterol showed the most responsiveness to treatment change. CONCLUSIONS: Lipid monitoring is increasingly common, but current guidelines vary. No single measure was best on all three criteria. Total cholesterol did not rank highly on any single criterion. However, measurements based on cholesterol subfractions—non-HDL cholesterol (total cholesterol minus HDL cholesterol) and the two ratios—appeared superior to total cholesterol or any of the apolipoprotein options. Guidelines should consider using non-HDL cholesterol or a ratio measure for initial treatment decisions and subsequent monitoring

Topological Optimization of the Evaluation of Finite Element Matrices

We present a topological framework for finding low-flop algorithms for evaluating element stiffness matrices associated with multilinear forms for finite element methods posed over straight-sided affine domains. This framework relies on phrasing the computation on each element as the contraction of each collection of reference element tensors with an element-specific geometric tensor. We then present a new concept of complexity-reducing relations that serve as distance relations between these reference element tensors. This notion sets up a graph-theoretic context in which we may find an optimized algorithm by computing a minimum spanning tree. We present experimental results for some common multilinear forms showing significant reductions in operation count and also discuss some efficient algorithms for building the graph we use for the optimization

Non semi-simple sl(2) quantum invariants, spin case

Invariants of 3-manifolds from a non semi-simple category of modules over a version of quantum sl(2) were obtained by the last three authors in [arXiv:1404.7289]. In their construction the quantum parameter $q$ is a root of unity of order $2r$ where $r>1$ is odd or congruent to $2$ modulo $4$. In this paper we consider the remaining cases where $r$ is congruent to zero modulo $4$ and produce invariants of $3$-manifolds with colored links, equipped with generalized spin structure. For a given $3$-manifold $M$, the relevant generalized spin structures are (non canonically) parametrized by $H^1(M;\mathbb C/2\mathbb Z)$.Comment: 13 pages, 16 figure

Atomic Hydrogen Cleaning of Polarized GaAs Photocathodes

Atomic hydrogen cleaning followed by heat cleaning at 450$^\circ$C was used to prepare negative-electron-affinity GaAs photocathodes. When hydrogen ions were eliminated, quantum efficiencies of 15% were obtained for bulk GaAs cathodes, higher than the results obtained using conventional 600$^\circ$C heat cleaning. The low-temperature cleaning technique was successfully applied to thin, strained GaAs cathodes used for producing highly polarized electrons. No depolarization was observed even when the optimum cleaning time of about 30 seconds was extended by a factor of 100