In-place Graph Rewriting with Interaction Nets

An algorithm is in-place, or runs in-situ, when it does not need any additional memory to execute beyond a small constant amount. There are many algorithms that are efficient because of this feature, therefore it is an important aspect of an algorithm. In most programming languages, it is not obvious when an algorithm can run in-place, and moreover it is often not clear that the implementation respects that idea. In this paper we study interaction nets as a formalism where we can see directly, visually, that an algorithm is in-place, and moreover the implementation will respect that it is in-place. Not all algorithms can run in-place however. We can nevertheless still use the same language, but now we can annotate parts of the algorithm that can run in-place. We suggest an annotation for rules, and give an algorithm to find this automatically through analysis of the interaction rules.Comment: In Proceedings TERMGRAPH 2016, arXiv:1609.0301

Independent effects of 7-days imposed exercise on free-living energy balance and appetite-regulating hormones in males

A thesis submitted to the University of Bedfordshire, in fulfilment of the requirements for the degree of Masters of Science by Research at the Institute for Sport and Physical Activity Research (ISPAR).Study 1 examined the reliability of a photographic food diary (with additional written details) on free-living energy intake (EI) in 13 healthy males. Daily average EI did not differ significantly between two, 7-day periods (p = 0.116) but a large systematic bias (143 ± 715 kcal.day-1) and wide limits of agreement (LoA) (-1258 to 1545 kcal.day-1) were found. Study 2 examined the influence of imposed exercise (7 days) on energy balance and the acylated ghrelin and total PYY response to a meal. Five healthy males completed two, 7-day trials in a crossover randomised design: no exercise (N-EX) and exercise (EX; ~69% V\u101236 O2peak expending an average 815 kcal.day-1). EI and EE were assessed throughout each trial. Blood and appetite ratings (visual analogue scales; VAS) were collected the day prior to and 70 hours post each trial (fasting and for 3 hours postprandial; a final VAS after an ad libitum meal). Exercise significantly increased EI by 27% (p = 0.005), although participants remained in an energy deficit. Appetite regulating hormones and appetite ratings did not alter from pre- to 70 hours post-intervention. Thus, 7-days of imposed exercise induced a partial compensation through EI, without changes in appetite hormones or appetite ratings

A study of platelet aggregation in whole blood from normal and prothrombotic subjects

The aim of this thesis was to study platelet function in whole blood, in an environment close to normal physiology. It was anticipated that such studies in whole blood would be more sensitive to in vivo changes than studies on isolated platelets, since all of the formed elements are present, there is less risk of in vitro activation, and labile substances should still be present. This approach was thought to be particularly applicable to platelet studies in blood from patients with prothrombotic states where the mechanism of thrombosis is unclear, and for examining anti-platelet drug efficacy. Existing methods were inadequate and it was first necessary to develop new techniques using electrical impedance. Sensitive and reproducible impedance methods were developed, and these were especially useful for blood samples with platelet counts below 50*10⁹/1. A particular type of aggregate was detected, requiringirreversible aggregation, thromboxane A2 generation, but not ADP secretion. Measurements in non-anticoagulated blood allowed a global view of haemostasis, reflecting interactions of platelets, neutrophils, thrombin, and fibrin. In the presence of calcium++, neutrophils and thrombin potentiated the aggregation response. There was excessive aggregation in non-anticoagulated blood from patients with multi-organ failure. This was related to increased neutrophil count, enhanced thrombin generation, and reciprocal cell activation. Such patients may benefit from eicosanoid antagonists and protease inhibitors to prevent unwarranted activation of coagulation and cellular defense mechanisms. Chronic arteriopaths showed reduced aggregation compatible with in vivo activation. Prostacyclin analogue infusions were less effective as judged ex vivo in whole blood compared to traditional techniques; continuous infusion resulted in progressively decreasing platelet sensitivity, rebound hyperaggregability, and increased serum thromboxane B2. Cigarette smoking caused increased platelet aggregation and adherence to vascular endothelium. Increased aggregation was seen in multi-organ failure, which traditional methods would not have detected. There appear to be multiple interactions between leucocytes and platelets

Development of a novel therapy for the prevention or reduction of cutaneous scarring.

There currently exists no effective therapy for either the prophylaxis or treatment of cutaneous scarring. The myofibroblast has been implicated in the aetiology of pathological scars, and therefore the development of therapies to prevent scarring in man have focussed upon the prevention of the myofibroblast phenotype. The aim of this thesis was to investigate whether insulin could prevent dermal fibroblast - myofibroblast differentiation in vitro and in vivo. Three preparations of insulin that are in common clinical usage were evaluated for their efficacy in reducing fibroblast - myofibroblast differentiation in human dermal fibroblast cell cultures. Using immunohistochemical and western blotting techniques, insulin was shown to be effective in reducing myofibroblast number. The effect of insulin on fibroblast proliferation, total protein and collagen synthesis was also determined. In addition, the effect of insulin on the contraction of 3D collagen gels was evaluated. Using immunohistochemical techniques, the effect of growth factors known to inhibit apoptosis were evaluated for their abilities to reduce fibroblast - myofibroblast differentiation. In addition, prior to commencement of in vivo studies, the effectiveness of insulin in the presence of its physiological antagonists was established. To investigate the effect of insulin in vivo, the compound was tested on healing murine incisional and excisional wounds. Incisional wounds proved to be the most reliable for interpretation. Myofibroblast numbers were assessed using both immunohistochemical and western blotting. Progress towards the development of a novel therapy for the prevention or reduction of cutaneous scarring has been achieved by assessing the effects of insulin both in vitro and in vivo

The Semantics of Graph Programs

GP (for Graph Programs) is a rule-based, nondeterministic programming language for solving graph problems at a high level of abstraction, freeing programmers from handling low-level data structures. The core of GP consists of four constructs: single-step application of a set of conditional graph-transformation rules, sequential composition, branching and iteration. We present a formal semantics for GP in the style of structural operational semantics. A special feature of our semantics is the use of finitely failing programs to define GP's powerful branching and iteration commands

Parallel Evaluation of Interaction Nets: Case Studies and Experiments

Interaction nets are a particular kind of graph rewriting system that have many properties that make them useful for capturing sharing and parallelism. There have been a number of research efforts towards implementing interaction nets in parallel, and these have focused on the implementation technologies. In this paper we investigate a related question: when is an interaction net system suitable for parallel evaluation? We observe that some nets cannot benefit from parallelism (they are sequential) and some have the potential to be evaluated in a highly parallel way. This first investigation aims to highlight a number of issues, by presenting experimental evidence for a number of case studies. We hope this can be used to help pave the way to a wider use of this technology for parallel evaluation

The principles of an ideal homelessness administrative data system: lessons from global practice

Discussions of homelessness measurement methodologies have largely focused on the generation of primary data, for example point-in-time counts. Though there is long standing tradition in the use of administrative data for measuring homelessness, relatively little examination of administrative data as method exists, i.e. the set of socio-technical practices through which administrative data are generated. This paper undertakes an internationally informed review of 50 administrative data systems in order to deconstruct these systems and stage a methodological discussion. Uniquely, the review included systems from other policy fields outside of homelessness, including health and education, in order to learn from wider data practices. The discussion elaborates on six key design considerations driving administrative data systems, including; function; data architecture; data quality; ethico-legal considerations; privacy preservation; and data access and accessibility. To conclude, we outline what an ideal data system would look like in order to improve the potential use of administrative data to measure homelessness and our response to it, but, more importantly, in mobilising data more effectively in order to facilitate research and operational uses of data. The six design elements can inform future homelessness administrative data systems, whilst also sensitising researchers and users of current administrative data to its (socially) constructed nature