1,429 research outputs found

    Capturing Hiproofs in HOL Light

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    Hierarchical proof trees (hiproofs for short) add structure to ordinary proof trees, by allowing portions of trees to be hierarchically nested. The additional structure can be used to abstract away from details, or to label particular portions to explain their purpose. In this paper we present two complementary methods for capturing hiproofs in HOL Light, along with a tool to produce web-based visualisations. The first method uses tactic recording, by modifying tactics to record their arguments and construct a hierarchical tree; this allows a tactic proof script to be modified. The second method uses proof recording, which extends the HOL Light kernel to record hierachical proof trees alongside theorems. This method is less invasive, but requires care to manage the size of the recorded objects. We have implemented both methods, resulting in two systems: Tactician and HipCam

    Immunogenicity of a lowcost hepatitis Bvaccine in the South African Expanded Programme on Immunisation

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    Background. A low-cost, 'flash' heat-inactivated hepatitis B vaccine with enhanced immunogenicity allowing for a relatively low dose (Hepaccine B; Cheil Foods and Chemicals, Korea) was introduced into the South African Expanded Programme on Immunisation during 1995 to immunise infants against hepatitis B. To detennnine the seroresponse of this vaccine in South Africa, a country with a high hepatitis B virus (HBV) prevalence, a field trial was conducted in a rural health clinic.Methods. The immunogenicity of Hepaccine B, containing 1.5IJg/O.5 ml, was studied in 186 black infants attending the Soshanguve III clinic, north-west of Pretoria. Infants receiving three consecutive doses in the anterolateral thigh at 6,10 and 14 weeks were monitored. The doses were administered concurrently with their routine oral polio vaccine (OPV) and diphtheria, pertussis and tetanus (DPT) immunisations. Vaccine side-effects were recorded. Blood specimens were collected 3 months after the final vaccination. Sera were tested for antibodies to hepatitis B surface antigen (anti-HBs) by IMx AUSAB (Abbott Laboratories, USA). Levels of anti-HBs were determined by comparison with standard reference preparations and expressed in mlUlml.Results. Side-effects of the vaccine were minor, with limited local reaction at the site of administration. The· anti-HBs seroconversion rate was 93.0%, based on a titre of ~ 10 mlUlml with a geometric mean titre of 257.58 mlUlml.Conclusions. Administration of 1.5 I-Ig doses of Hepaccine B at 6, 10 and 14 weeks is safe and highly immunogenic in black South African infants, and this vaccine is suitable for use in countries with high HBV prevalences such as in Africa. The use of an economical hepatitis B vaccine would greatly facilitate the prevention of hepatitis B in these countries

    Thyroid stem cells: concept and clinical implications

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    Thyroid pathology is the commonest endocrine surgical problem encountered. However, the study of thyroid stem cells is relatively new in the field of stem cell research. Since the identification of thyroid stem cells in 1992, research interest in this area has been increasing mainly based on furthering our knowledge of the biology of these important cells that are thought to be responsible for tumourigenesis and propagation of cancers. This article reviews the current science and biology of thyroid stem cells and summarizes their potential role in the general management of thyroid disorders

    How effective is the Forestry Commission Scotland's woodland improvement programme--'Woods In and Around Towns' (WIAT)--at improving psychological well-being in deprived urban communities? A quasi-experimental study

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    Introduction: There is a growing body of evidence that suggests that green spaces may positively influence psychological well-being. This project is designed to take advantage of a natural experiment where planned physical and social interventions to enhance access to natural environments in deprived communities provide an opportunity to prospectively assess impacts on perceived stress and mental well-being.<p></p> Study design and methods: A controlled, prospective study comprising a repeat cross-sectional survey of residents living within 1.5 km of intervention and comparison sites. Three waves of data will be collected: prephysical environment intervention (2013); postphysical environment intervention (2014) and postwoodland promotion social intervention (2015). The primary outcome will be a measure of perceived stress (Perceived Stress Scale) preintervention and postintervention. Secondary, self-report outcomes include: mental well-being (Short Warwick-Edinburgh Mental Well-being Scale), changes in physical activity (IPAQ-short form), health (EuroQoL EQ-5D), perception and use of the woodlands, connectedness to nature (Inclusion of Nature in Self Scale), social cohesion and social capital. An environmental audit will complement the study by evaluating the physical changes in the environment over time and recording any other contextual changes over time. A process evaluation will assess the implementation of the programme. A health economics analysis will assess the cost consequences of each stage of the intervention in relation to the primary and secondary outcomes of the study.<p></p> Ethics and dissemination: Ethical approval has been given by the University of Edinburgh, Edinburgh College of Art Research, Ethics and Knowledge Exchange Committee (ref. 19/06/2012). Findings will be disseminated through peer-reviewed publications, national and international conferences and, at the final stage of the project, through a workshop for those interested in implementing environmental interventions.<p></p&gt

    Amortised resource analysis with separation logic

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    Type-based amortised resource analysis following Hofmann and Jost—where resources are associated with individual elements of data structures and doled out to the programmer under a linear typing discipline—have been successful in providing concrete resource bounds for functional programs, with good support for inference. In this work we translate the idea of amortised resource analysis to imperative languages by embedding a logic of resources, based on Bunched Implications, within Separation Logic. The Separation Logic component allows us to assert the presence and shape of mutable data structures on the heap, while the resource component allows us to state the resources associated with each member of the structure. We present the logic on a small imperative language with procedures and mutable heap, based on Java bytecode. We have formalised the logic within the Coq proof assistant and extracted a certified verification condition generator. We demonstrate the logic on some examples, including proving termination of in-place list reversal on lists with cyclic tails

    Risk and uncertainty assessment of volcanic hazards

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    Pressure pain thresholds in a real-world chiropractic setting: Topography, changes after treatment, and clinical relevance?

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    Background Changes in pain sensitivity are a commonly suggested mechanism for the clinical effect of spinal manipulative therapy (SMT). Most research has examined pressure pain thresholds (PPT) and has primarily been conducted in controlled experimental setups and on asymptomatic populations. Many important factors are likely to differ between research and clinical settings, which may affect PPT changes following SMT. Therefore, we planned to investigate PPT before and after clinical chiropractic care and investigate relationships with various potentially clinically-relevant factors. Methods We recruited participants from four Danish chiropractic clinics between May and August 2021. A total of 129 participants (72% of the invited) were included. We measured PPT at eight pre-determined test sites (six spinal and two extra-spinal) immediately before (pre-session) and immediately after (post-session) the chiropractic consultation. We used regression analyses to investigate PPT changes, including the following factors: (i) vertebral distance to the nearest SMT site, (ii) rapid clinical response, (iii) baseline PPT, (iv) number of SMTs performed, (v) at the region of clinical pain compared to other regions, and (vi) if other non-SMT treatment was provided. We also performed topographic mapping of pre-session PPTs. Results After the consultation, there was a non-significant mean increase in PPT of 0.14 kg (95% CIs = − 0.01 to 0.29 kg). No significant associations were found with the distance between the PPT test site and nearest SMT site, the clinical response of participants to treatment, the pre-session PPT, the total number of SMTs performed, or the region/s of clinical pain. A small increase was observed if myofascial treatment was also provided. Topographic mapping found greater pre-session PPTs in a caudal direction, not affected by the region/s of clinical pain. Conclusions This study of real-world chiropractic patients failed to demonstrate a substantial local or generalized increase in PPT following a clinical encounter that included SMT. This runs counter to prior laboratory research and questions the generalizability of highly experimental setups investigating the effect of SMT on PPT to clinical practice
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