Using software development progress data to understand threats to project outcomes

Peer reviewe

Pulmonary artery smooth muscle cells response to vaso-active stimulations in a real-time 3-Dimensional model

INTRODUCTION: The tone of the pulmonary arteries is the summation of the activity of each smooth muscle cell (PASMC) within a vessel wall and its interaction with the endothelial cells and extracellular matrix (including collagen). There are reported phenotypic differences between PASMC in the inner & outer layers of pulmonary artery walls1. The response of a tissue engineered blood vessel to contractile and relaxing stimulants in-vitro is essential to predicting the response of the physiological and pathological vessels in-vivo. Previous work showed that pulmonary artery relaxation to nitric oxide is inhibited after exposure to chronic hypoxia 2. We hypothesised that PASMC will differ in their ability to contract or relax a 3D collagen gel. Using a Culture Force Monitor (CFM) we sought to quantify the cellular response of PASMC derived from inner and outer normal and hypoxic arteries, harvested from piglet models, over 24 hours in response to contractile agonists and relaxing antagonists

Cost-effective aperture arrays for SKA Phase 1: single or dual-band?

An important design decision for the first phase of the Square Kilometre Array is whether the low frequency component (SKA1-low) should be implemented as a single or dual-band aperture array; that is, using one or two antenna element designs to observe the 70-450 MHz frequency band. This memo uses an elementary parametric analysis to make a quantitative, first-order cost comparison of representative implementations of a single and dual-band system, chosen for comparable performance characteristics. A direct comparison of the SKA1-low station costs reveals that those costs are similar, although the uncertainties are high. The cost impact on the broader telescope system varies: the deployment and site preparation costs are higher for the dual-band array, but the digital signal processing costs are higher for the single-band array. This parametric analysis also shows that a first stage of analogue tile beamforming, as opposed to only station-level, all-digital beamforming, has the potential to significantly reduce the cost of the SKA1-low stations. However, tile beamforming can limit flexibility and performance, principally in terms of reducing accessible field of view. We examine the cost impacts in the context of scientific performance, for which the spacing and intra-station layout of the antenna elements are important derived parameters. We discuss the implications of the many possible intra-station signal transport and processing architectures and consider areas where future work could improve the accuracy of SKA1-low costing.Comment: 64 pages, 23 figures, submitted to the SKA Memo serie

Computer program to generate attitude error equations for a gimballed platform

Computer program for solving attitude error equations related to gimballed platform is described. Program generates matrix elements of attitude error equations when initial matrices and trigonometric identities have been defined. Program is written for IBM 360 computer

Software fault characteristics: A synthesis of the literature

Faults continue to be a significant problem in software. Understanding the nature of these faults is important for practitioners and researchers. There are many published fault characteristics schemes but no one scheme dominates. Consequently it is difficult for practitioners to effectively evaluate the nature of faults in their software systems, and it is difficult for researchers to compare the types of faults found by different fault detection techniques. In this paper we synthesise previous fault characteristics schemes into one comprehensive scheme. Our scheme provides a richer view of faults than the previous schemes published and presents a comprehensive, unified approach which accommodates the many previous schemes. A characteristics-based view of faults should be considered by future researchers in the analysis of software faults and in the design and evaluation of new fault detection tools. We recommend that our fault characteristics scheme be used as a benchmark scheme

An economic analysis of a pneumococcal vaccine programme in people aged over 64 years in a developed country setting.

BACKGROUND: Polysaccharide pneumococcal vaccination for older adults is being introduced in developed country settings. Evidence of protection by this vaccine against pneumococcal pneumonia, or confirmation that illness and death from bacteraemia are prevented, is currently limited. Decisions are often made based on partial information. We examined the policy implications by exploring the potential economic benefit to society and the health sector of pneumococcal vaccination in older adults. METHODS: A model to estimate the potential cost savings and cost-effectiveness of a polysaccharide pneumococcal vaccine programme was based on costs collected from patients, the literature, and routine health-services data. The effect of a pneumococcal vaccine (compared with no vaccination) was examined in a hypothetical cohort aged over 64 years. The duration of protection was assumed to be 10 years, with or without a booster at 5 years. RESULTS: If it were effective against morbidity from pneumococcal pneumonia, the main burden from pneumococcal disease, the vaccine could be cost-neutral to society or the health sector at low efficacy (28 and 37.5%, respectively, without boosting and with 70% coverage). If it were effective against morbidity from bacteraemia only, the vaccine's efficacy would need to be 75 and 89%, respectively. If protection against both morbidity and mortality from pneumococcal bacteraemia was 50%, the net cost to society would be 2500 pounds per year of life saved ( 3365 pounds from the health-sector perspective). Results were sensitive to incidence, case-fatality rates, and costs of illness. CONCLUSIONS: A vaccine with moderate efficacy against bacteraemic illness and death would be cost-effective. If it also protected against pneumonia, it would be cost-effective even if its efficacy were low

The principle of equivalence and projective structure in space-times

This paper discusses the extent to which one can determine the space-time metric from a knowledge of a certain subset of the (unparametrised) geodesics of its Levi-Civita connection, that is, from the experimental evidence of the equivalence principle. It is shown that, if the space-time concerned is known to be vacuum, then the Levi-Civita connection is uniquely determined and its associated metric is uniquely determined up to a choice of units of measurement, by the specification of these geodesics. It is further demonstrated that if two space-times share the same unparametrised geodesics and only one is assumed vacuum then their Levi-Civita connections are again equal (and so the other metric is also a vacuum metric) and the first result above is recovered.Comment: 23 pages, submitted to Classical and Quantum Gravit

Quantitative Electron Probe X-Ray Microanalysis in Biology

This review summarizes existing formalisms for the quantitative analysis of biological specimens, and considers the analysis of bulk specimens, micro-droplets, homogenates, and thin or ultrathin sections, respectively. For (ultra)thin sections, one may use elemental ratios for semi-quantitative analysis, measure elemental concentrations as mmol/volume using peripheral standards, or as mmol/kg using the continuum method. Often it is physiologically more relevant to know the concentration of ions as mmol/kg water. This can be achieved by analysing the specimen first in the frozen-hydrated state and then again after freeze-drying, or by using a peripheral standard. Attention has to be given to the selection of a proper preparative method to ensure biologically relevant quantitative results. Quantitative analysis of sections of freeze-dried, embedded tissue will, due to tissue shrinkage during freeze-drying and incomplete penetration of resin, result in data that are intermediate between wet weight concentrations and dry weight concentrations. Analysis under cold-stage conditions may generally be expected to reduce mass loss during analysis