Enhancing Reuse of Constraint Solutions to Improve Symbolic Execution

Constraint solution reuse is an effective approach to save the time of constraint solving in symbolic execution. Most of the existing reuse approaches are based on syntactic or semantic equivalence of constraints; e.g. the Green framework is able to reuse constraints which have different representations but are semantically equivalent, through canonizing constraints into syntactically equivalent normal forms. However, syntactic/semantic equivalence is not a necessary condition for reuse--some constraints are not syntactically or semantically equivalent, but their solutions still have potential for reuse. Existing approaches are unable to recognize and reuse such constraints. In this paper, we present GreenTrie, an extension to the Green framework, which supports constraint reuse based on the logical implication relations among constraints. GreenTrie provides a component, called L-Trie, which stores constraints and solutions into tries, indexed by an implication partial order graph of constraints. L-Trie is able to carry out logical reduction and logical subset and superset querying for given constraints, to check for reuse of previously solved constraints. We report the results of an experimental assessment of GreenTrie against the original Green framework, which shows that our extension achieves better reuse of constraint solving result and saves significant symbolic execution time.Comment: this paper has been submitted to conference ISSTA 201

The feasibility of a novel group self-management intervention for stroke

Background: Stroke survivors consistently report long term unmet needs. Unlike other chronic conditions stroke self-management programmes have been slow to emerge. Bridges self-management is a one-to one approach used by some UK NHS stroke services and aims to increase self-efficacy and confidence to manage long term needs post stroke. However, a one-to-one delivery does not facilitate peer support, which stroke survivors report as being valuable to the self-management process. In order to evaluate the potential for a one-one programme such as Bridges to be delivered in a group setting important parameters need to be explored, such as, acceptability, fidelity and outcome measure effect sizes. The MRC calls this type of research ‘feasibility’, and labels it an essential part of complex intervention development. The aim of this thesis was to explore the feasibility of delivering a one-to-one stroke self-management intervention (Bridges) in a group setting. Method: Feasibility was explored across three phases: (1) the development phase included patient involvement activities, stroke survivor interviews, and a systematic review to inform the design of a four-week self-management intervention, (2) the implementation phase monitored intervention delivery, 60 stroke survivors were randomised to the intervention or waitlist condition, (3) the evaluation phase used a mixed methods approach to explore acceptability and potential mechanisms of change as well as the effect of the intervention on mood, self-efficacy, quality of life and activities of daily living. Results: Overall it was feasible to adapt Bridges for group delivery. The intervention had high fidelity to the protocol. Recruitment occurred at a mean rate of 6.6 per month with a 21.667% drop out rate. The intervention was found to be acceptable to stroke survivors and carers. Potential mechanisms of change included vicarious learning and supported goal setting. At six-months post-baseline, outcomes had improved in favour of the intervention group. A number of recommendations were made to further develop the intervention, and for subsequent research on this topic. Conclusion: The thesis concludes that delivering a group self-management intervention for stroke may offer some benefits to stroke survivors and suggests research progress to a definitive trial

Mission-Aware Cyber-Physical Optimization on a Tabletop Satellite

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/106493/1/AIAA2013-4807.pd

Common colorectal cancer risk alleles contribute to the multiple colorectal adenoma phenotype, but do not influence colonic polyposis in FAP

The presence of multiple (5-100) colorectal adenomas suggests an inherited predisposition, but the genetic aetiology of this phenotype is undetermined if patients test negative for Mendelian polyposis syndromes such as familial adenomatous polyposis (FAP) and MUTYH-associated polyposis (MAP). We investigated whether 18 common colorectal cancer (CRC) predisposition single-nucleotide polymorphisms (SNPs) could help to explain some cases with multiple adenomas who phenocopied FAP or MAP, but had no pathogenic APC or MUTYH variant. No multiple adenoma case had an outlying number of CRC SNP risk alleles, but multiple adenoma patients did have a significantly higher number of risk alleles than population controls (P=5.7 × 10(-7)). The association was stronger in those with ≥10 adenomas. The CRC SNPs accounted for 4.3% of the variation in multiple adenoma risk, with three SNPs (rs6983267, rs10795668, rs3802842) explaining 3.0% of the variation. In FAP patients, the CRC risk score did not differ significantly from the controls, as we expected given the overwhelming effect of pathogenic germline APC variants on the phenotype of these cases. More unexpectedly, we found no evidence that the CRC SNPs act as modifier genes for the number of colorectal adenomas in FAP patients. In conclusion, common colorectal tumour risk alleles contribute to the development of multiple adenomas in patients without pathogenic germline APC or MUTYH variants. This phenotype may have 'polygenic' or monogenic origins. The risk of CRC in relatives of multiple adenoma cases is probably much lower for cases with polygenic disease, and this should be taken into account when counselling such patients

One size does not fit all - stroke survivor's views on group self-management interventions

INTRODUCTION: Stroke is the main cause of complex disability in the UK. Many stroke survivors feel abandoned when rehabilitation ends and more than half are left with long-term unmet needs. There is now emerging interest in whether group self-management programs (SMP) specifically for stroke survivors could help. However, more work is required to understand the acceptability of group SMPs to stroke survivors and the factors of concern that could impact efficacy. PURPOSE: The purpose of this study is to explore stroke survivor's views on (1) possible benefits of a group SMP, (2) possible challenges of a group SMP, and (3) when/where to implement a SMP in an individual's stroke journey. METHOD: Fourteen stroke survivors took part in semi-structured interviews, which were analyzed using an inductive thematic approach. RESULTS: Three main themes were identified in the data: (1) a space to share support, (2) it is not a one size fits all problem, and (3) how is it all going to happen? CONCLUSION: A varied group of stroke survivors can provide valuable insight and ideas about how group SMP's should be constructed. To the best of our knowledge, this is the first patient engagement study that explores group SMPs for stroke. In future work, researchers may find it helpful to consider the findings from this study to inform the design of group SMPs. Implications for Rehabilitation There is interest in whether unmet needs after stroke could be addressed through a group self-management program (SMP). Stroke survivors can provide valuable insight and ideas about how group SMPs should be constructed. Group SMPs should carefully consider: how to create a safe space in which stroke survivors feel comfortable, the impact of the facilitators, tailoring the group to the individual, the presence of carers, and the emotional impact of a group SMP

An evaluation of the rat intestinal monoamine biogeography days following exposure to acute stress

Stress-induced abnormalities in gut monoamine levels (e.g., serotonin, dopamine, norepinephrine) have been linked to gastrointestinal (GI) dysfunction, as well as the worsening of symptoms in GI disorders. However, the influence of stress on changes across the entire intestinal monoamine biogeography has not been well-characterized, especially in the days following stress exposure. Therefore, the aim of this study was to comprehensively assess changes to monoamine neurochemical signatures across the entire rat intestinal tract days after exposure to an acute stressor. To the end, adult male F344 rats were subjected to an episode of unpredictable tail shocks (acute stress) or left undisturbed. Forty-eight hours later rats were euthanized either following a 12 h period of fasting or 30 min of food access to evaluate neurochemical profiles during the peri- and early postprandial periods. Monoamine-related neurochemicals were measured via UHPLC in regions of the small intestine (duodenum, jejunum, ileum), large intestine (cecum, proximal colon, distal colon), cecal contents, fecal contents, and liver. The results suggest a relatively wide-spread increase in measures of serotonin activity across intestinal regions can be observed 48 h after exposure to acute stress, however some evidence was found supporting localized differences in serotonin metabolization. Moreover, acute stress exposure reduced catecholamine-related neurochemical concentrations most notably in the ileum, and to a lesser extent in the cecal contents. Next, stress-related fecal serotonin concentrations were consistent with intestinal profiles. However, fecal dopamine was elevated in association with stress, which did not parallel findings in any other intestinal area. Finally, stress exposure and the food access period together only had minor effects on intestinal monoamine profiles. Taken together, these data suggest nuanced differences in monoaminergic profiles exist across intestinal regions the days following exposure to an acute stressor, highlighting the importance of assessments that consider the entire intestinal tract biogeography when investigating stress-related biological outcomes that may be relevant to GI pathophysiology

A cross-sectional study of malaria transmission in suggests the existence of a potential bridge vector susceptible of ensuring the transfer of simian malaria parasites to humans

Introduction: Despite all the efforts made to control or even eliminate malaria, the disease continues to claim the highest number of victims of vector-borne pathogens in the world and Sub-Saharan countries bear the heaviest burden. The lack of knowledge of the role of various protagonists involved in the transmission of this parasitic disease, such as mosquito vectors and the plasmodial species they transmit as well as the host species they infect in a locality, constitutes one of the main causes of the persistence of malaria. In Gabon, in several areas, entomological data on malaria transmission remain poorly known. Thus, this study aimed to determine the diversity of Anopheles involved in malaria transmission in different environments of the province of Nyanga in southwest Gabon.Methods: For this, an entomological study was carried out in the four main localities of the province of Nyanga to provide answers to these shortcomings. Mosquitoes were collected over several nights using the human landing catch method. The identification of Anopheles and malaria parasites circulating in the different sites was achieved by combining morphological and molecular analysis tools.Results: A total of five hundred and ninety-one (591) mosquitoes belonging to the Culicidae family were collected. From this collection of adult mosquitoes, nine species of Anopheles mosquitoes notably species of the Anopheles nili complex (53.46%) followed by those of Anopheles gambiae complex (22.01%), Anopheles funestus group (18.24%), Anopheles moucheti complex (5.66%) and Anopheles hancocki (0.63%). Approximately 18 percent of these Anopheles species were infected with Plasmodium spp. Anopheles funestus, known to be involved in malaria transmission to humans, and An. moucheti-like, recently discovered in Gabon, and whose status in Plasmodium transmission is not yet elucidated, were found to be infected with great ape Plasmodium.Discussion: Our results raise the question of the potential switch of simian malaria parasites to humans. If these observations are confirmed in the future, and the infective capacity of the bridge vectors is demonstrated, this new situation could ultimately constitute an obstacle to progress in the fight against malaria

Influence of production variables and starting material on charcoal stable isotopic and molecular characteristics

We present a systematic study on the effect of starting species, gas composition, temperature, particle size and duration of heating upon the molecular and stable isotope composition of high density (mangrove) and low density (pine) wood. In both pine and mangrove, charcoal was depleted in o13C relative to the starting wood by up to 1.6% and 0.8%, respectively. This is attributed predominantly to the progressive loss of isotopically heavier polysaccharides, and kinetic effects of aromatization during heating. However, the pattern of o13C change was dependant upon both starting species and atmosphere, with different structural changes associated with charcoal production from each wood type elucidated by Solid-State o13C Nuclear Magnetic Resonance Spectroscopy. These are particularly evident at lower temperatures, where variation in the oxygen content of the production atmosphere results in differences in the thermal degradation of cellulose and lignin. It is concluded that production of charcoal from separate species in identical conditions, or from a single sample exposed to different production variables, can result in significantly different o13C of the resulting material, relative to the initial wood. These results have implications for the use of charcoal isotope composition to infer past environmental change