The Stress Distribution on the Zygapophyseal Joint of Lumbar Vertebra by ANSYS Program

Zygapophyseal joints (or facet joints), are a plane synovial joint which located between the articular facet processes of the vertebral arch which is freely guided movable joints. Ten dried vertebrae were used for the lumbar region and taking (L4) as a sample to reveal stress pathways across the joints by using ANSYS program under different loading conditions which used Finite Elements Analysis model. Results obtained from the ANSYS program are important in understanding the boundary conditions for load analysis and the points of stress concentration which explained from the anatomical point of view and linked to muscle and ligament attachments. This model used as a computational tool to joint biomechanics and to prosthetic implant analysis

A Denotational Semantics for First-Order Logic

In Apt and Bezem [AB99] (see cs.LO/9811017) we provided a computational interpretation of first-order formulas over arbitrary interpretations. Here we complement this work by introducing a denotational semantics for first-order logic. Additionally, by allowing an assignment of a non-ground term to a variable we introduce in this framework logical variables. The semantics combines a number of well-known ideas from the areas of semantics of imperative programming languages and logic programming. In the resulting computational view conjunction corresponds to sequential composition, disjunction to ``don't know'' nondeterminism, existential quantification to declaration of a local variable, and negation to the ``negation as finite failure'' rule. The soundness result shows correctness of the semantics with respect to the notion of truth. The proof resembles in some aspects the proof of the soundness of the SLDNF-resolution.Comment: 17 pages. Invited talk at the Computational Logic Conference (CL 2000). To appear in Springer-Verlag Lecture Notes in Computer Scienc

Independence in CLP Languages

Studying independence of goals has proven very useful in the context of logic programming. In particular, it has provided a formal basis for powerful automatic parallelization tools, since independence ensures that two goals may be evaluated in parallel while preserving correctness and eciency. We extend the concept of independence to constraint logic programs (CLP) and prove that it also ensures the correctness and eciency of the parallel evaluation of independent goals. Independence for CLP languages is more complex than for logic programming as search space preservation is necessary but no longer sucient for ensuring correctness and eciency. Two additional issues arise. The rst is that the cost of constraint solving may depend upon the order constraints are encountered. The second is the need to handle dynamic scheduling. We clarify these issues by proposing various types of search independence and constraint solver independence, and show how they can be combined to allow dierent optimizations, from parallelism to intelligent backtracking. Sucient conditions for independence which can be evaluated \a priori" at run-time are also proposed. Our study also yields new insights into independence in logic programming languages. In particular, we show that search space preservation is not only a sucient but also a necessary condition for ensuring correctness and eciency of parallel execution

Implementing integrated care clinics for HIV-infection, diabetes and hypertension in Uganda (INTE-AFRICA): process evaluation of a cluster randomised controlled trial

BACKGROUND: Sub-Saharan Africa is experiencing a dual burden of chronic human immunodeficiency virus and non-communicable diseases. A pragmatic parallel arm cluster randomised trial (INTE-AFRICA) scaled up ‘one-stop’ integrated care clinics for HIV-infection, diabetes and hypertension at selected facilities in Uganda. These clinics operated integrated health education and concurrent management of HIV, hypertension and diabetes. A process evaluation (PE) aimed to explore the experiences, attitudes and practices of a wide variety of stakeholders during implementation and to develop an understanding of the impact of broader structural and contextual factors on the process of service integration. METHODS: The PE was conducted in one integrated care clinic, and consisted of 48 in-depth interviews with stakeholders (patients, healthcare providers, policy-makers, international organisation, and clinical researchers); three focus group discussions with community leaders and members (n = 15); and 8 h of clinic-based observation. An inductive analytical approach collected and analysed the data using the Empirical Phenomenological Psychological five-step method. Bronfenbrenner’s ecological framework was subsequently used to conceptualise integrated care across multiple contextual levels (macro, meso, micro). RESULTS: Four main themes emerged; Implementing the integrated care model within healthcare facilities enhances detection of NCDs and comprehensive co-morbid care; Challenges of NCD drug supply chains; HIV stigma reduction over time, and Health education talks as a mechanism for change. Positive aspects of integrated care centred on the avoidance of duplication of care processes; increased capacity for screening, diagnosis and treatment of previously undiagnosed comorbid conditions; and broadening of skills of health workers to manage multiple conditions. Patients were motivated to continue receiving integrated care, despite frequent NCD drug stock-outs; and development of peer initiatives to purchase NCD drugs. Initial concerns about potential disruption of HIV care were overcome, leading to staff motivation to continue delivering integrated care. CONCLUSIONS: Implementing integrated care has the potential to sustainably reduce duplication of services, improve retention in care and treatment adherence for co/multi-morbid patients, encourage knowledge-sharing between patients and providers, and reduce HIV stigma. TRIAL REGISTRATION NUMBER: ISRCTN43896688

The Lambek calculus with iteration: two variants

Formulae of the Lambek calculus are constructed using three binary connectives, multiplication and two divisions. We extend it using a unary connective, positive Kleene iteration. For this new operation, following its natural interpretation, we present two lines of calculi. The first one is a fragment of infinitary action logic and includes an omega-rule for introducing iteration to the antecedent. We also consider a version with infinite (but finitely branching) derivations and prove equivalence of these two versions. In Kleene algebras, this line of calculi corresponds to the *-continuous case. For the second line, we restrict our infinite derivations to cyclic (regular) ones. We show that this system is equivalent to a variant of action logic that corresponds to general residuated Kleene algebras, not necessarily *-continuous. Finally, we show that, in contrast with the case without division operations (considered by Kozen), the first system is strictly stronger than the second one. To prove this, we use a complexity argument. Namely, we show, using methods of Buszkowski and Palka, that the first system is $\Pi_1^0$-hard, and therefore is not recursively enumerable and cannot be described by a calculus with finite derivations

Women living with HIV, diabetes and/or hypertension multi-morbidity in Uganda: a qualitative exploration of experiences accessing an integrated care service

Purpose: Women experience a triple burden of ill-health spanning non-communicable diseases (NCDs), reproductive and maternal health conditions and human immunodeficiency virus (HIV) in sub-Saharan Africa. Whilst there is research on integrated service experiences of women living with HIV (WLHIV) and cancer, little is known regarding those of WLHIV, diabetes and/or hypertension when accessing integrated care. Our research responds to this gap. Design/methodology/approach: The INTE-AFRICA project conducted a pragmatic parallel arm cluster randomised trial to scale up and evaluate “one-stop” integrated care clinics for HIV-infection, diabetes and hypertension at selected primary care centres in Uganda. A qualitative process evaluation explored and documented patient experiences of integrated care for HIV, diabetes and/or hypertension. In-depth interviews were conducted using a phenomenological approach with six WLHIV with diabetes and/or hypertension accessing a “one stop” clinic. Thematic analysis of narratives revealed five themes: lay health knowledge and alternative medicine, community stigma, experiences of integrated care, navigating personal challenges and health service constraints. Findings: WLHIV described patient pathways navigating HIV and diabetes/hypertension, with caregiving responsibilities, poverty, travel time and cost and personal ill health impacting on their ability to adhere to multi-morbid integrated treatment. Health service barriers to optimal integrated care included unreliable drug supply for diabetes/hypertension and HIV linked stigma. Comprehensive integrated care is recommended to further consider gender sensitive aspects of care. Originality/value: This study whilst small scale, provides a unique insight into the lived experience of WLHIV navigating care for HIV and diabetes and/or hypertension, and how a “one stop” integrated care clinic can support them (and their children) in their treatment journeys

An assertion language for constraint logic programs

In an advanced program development environment, such as that discussed in the introduction of this book, several tools may coexist which handle both the program and information on the program in different ways. Also, these tools may interact among themselves and with the user. Thus, the different tools and the user need some way to communicate. It is our design principie that such communication be performed in terms of assertions. Assertions are syntactic objects which allow expressing properties of programs. Several assertion languages have been used in the past in different contexts, mainly related to program debugging. In this chapter we propose a general language of assertions which is used in different tools for validation and debugging of constraint logic programs in the context of the DiSCiPl project. The assertion language proposed is parametric w.r.t. the particular constraint domain and properties of interest being used in each different tool. The language proposed is quite general in that it poses few restrictions on the kind of properties which may be expressed. We believe the assertion language we propose is of practical relevance and appropriate for the different uses required in the tools considered

Decentralising chronic disease management in sub-Saharan Africa: a protocol for the qualitative process evaluation of community-based integrated management of HIV, diabetes and hypertension in Tanzania and Uganda

Introduction: Sub-Saharan Africa continues to experience a syndemic of HIV and non-communicable diseases (NCDs). Vertical (stand-alone) HIV programming has provided high-quality care in the region, with almost 80% of people living with HIV in regular care and 90% virally suppressed. While integrated health education and concurrent management of HIV, hypertension and diabetes are being scaled up in clinics, innovative, more efficient and cost-effective interventions that include decentralisation into the community are required to respond to the increased burden of comorbid HIV/NCD disease. Methods and analysis This protocol describes procedures for a process evaluation running concurrently with a pragmatic cluster-randomised trial (INTE-COMM) in Tanzania and Uganda that will compare community-based integrated care (HIV, diabetes and hypertension) with standard facility-based integrated care. The INTE-COMM intervention will manage multiple conditions (HIV, hypertension and diabetes) in the community via health monitoring and adherence/lifestyle advice (medicine, diet and exercise) provided by community nurses and trained lay workers, as well as the devolvement of NCD drug dispensing to the community level. Based on Bronfenbrenner’s ecological systems theory, the process evaluation will use qualitative methods to investigate sociostructural factors shaping care delivery and outcomes in up to 10 standard care facilities and/ or intervention community sites with linked healthcare facilities. Multistakeholder interviews (patients, community health workers and volunteers, healthcare providers, policymakers, clinical researchers and international and non-governmental organisations), focus group discussions (community leaders and members) and non-participant observations (community meetings and drug dispensing) will explore implementation from diverse perspectives at three timepoints in the trial implementation. Iterative sampling and analysis, moving between data collection points and data analysis to test emerging theories, will continue until saturation is reached. This process of analytic reflexivity and triangulation across methods and sources will provide findings to explain the main trial findings and offer clear directions for future efforts to sustain and scale up community-integrated care for HIV, diabetes and hypertension. Ethics and dissemination The protocol has been approved by the University College of London (UK), the London School of Hygiene and Tropical Medicine Ethics Committee (UK), the Uganda National Council for Science and Technology and the Uganda Virus Research Institute Research and Ethics Committee (Uganda) and the Medical Research Coordinating Committee of the National Institute for Medical Research (Tanzania). The University College of London is the trial sponsor. Dissemination of findings will be done through journal publications and stakeholder meetings (with study participants, healthcare providers, policymakers and other stakeholders), local and international conferences, policy briefs, peer-reviewed journal articles and publications

Constraint rule-based programming of norms for electronic institutions

Peer reviewedPostprin

Constraint Logic Programming for Hedges: A Semantic Reconstruction

Abstract. We describe the semantics of CLP(H): constraint logic programming over hedges. Hedges are finite sequences of unranked terms, built over variadic function symbols and three kinds of variables: for terms, for hedges, and for function symbols. Constraints involve equations between unranked terms and atoms for regular hedge language membership. We give algebraic semantics of CLP(H) programs, define a sound, terminating, and incomplete constraint solver, and describe some fragments of constraints for which the solver returns a complete set of solutions.