2,128 research outputs found

    Relational semantics of linear logic and higher-order model-checking

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    In this article, we develop a new and somewhat unexpected connection between higher-order model-checking and linear logic. Our starting point is the observation that once embedded in the relational semantics of linear logic, the Church encoding of any higher-order recursion scheme (HORS) comes together with a dual Church encoding of an alternating tree automata (ATA) of the same signature. Moreover, the interaction between the relational interpretations of the HORS and of the ATA identifies the set of accepting states of the tree automaton against the infinite tree generated by the recursion scheme. We show how to extend this result to alternating parity automata (APT) by introducing a parametric version of the exponential modality of linear logic, capturing the formal properties of colors (or priorities) in higher-order model-checking. We show in particular how to reunderstand in this way the type-theoretic approach to higher-order model-checking developed by Kobayashi and Ong. We briefly explain in the end of the paper how his analysis driven by linear logic results in a new and purely semantic proof of decidability of the formulas of the monadic second-order logic for higher-order recursion schemes.Comment: 24 pages. Submitte

    On CSP and the Algebraic Theory of Effects

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    We consider CSP from the point of view of the algebraic theory of effects, which classifies operations as effect constructors or effect deconstructors; it also provides a link with functional programming, being a refinement of Moggi's seminal monadic point of view. There is a natural algebraic theory of the constructors whose free algebra functor is Moggi's monad; we illustrate this by characterising free and initial algebras in terms of two versions of the stable failures model of CSP, one more general than the other. Deconstructors are dealt with as homomorphisms to (possibly non-free) algebras. One can view CSP's action and choice operators as constructors and the rest, such as concealment and concurrency, as deconstructors. Carrying this programme out results in taking deterministic external choice as constructor rather than general external choice. However, binary deconstructors, such as the CSP concurrency operator, provide unresolved difficulties. We conclude by presenting a combination of CSP with Moggi's computational {\lambda}-calculus, in which the operators, including concurrency, are polymorphic. While the paper mainly concerns CSP, it ought to be possible to carry over similar ideas to other process calculi

    On the homomorphism order of labeled posets

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    Partially ordered sets labeled with k labels (k-posets) and their homomorphisms are examined. We give a representation of directed graphs by k-posets; this provides a new proof of the universality of the homomorphism order of k-posets. This universal order is a distributive lattice. We investigate some other properties, namely the infinite distributivity, the computation of infinite suprema and infima, and the complexity of certain decision problems involving the homomorphism order of k-posets. Sublattices are also examined.Comment: 14 page

    Critical role of the disintegrin metalloprotease ADAM-like Decysin-1 (ADAMDEC1) for intestinal immunity and inflammation

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    BACKGROUND AND AIMS: ADAM (A Disintegrin And Metalloproteinase) is a family of peptidase proteins, which have diverse roles in tissue homeostasis and immunity. Here, we study ADAM-like Decysin-1 (ADAMDEC1) a unique member of the ADAM family. ADAMDEC1 expression is restricted to the macrophage/dendritic cell populations of the gastrointestinal tract and secondary lymphoid tissue. The biological function of ADAMDEC1 is unknown but it has been hypothesised to play a role in immunity. The identification of reduced ADAMDEC1 expression in Crohn's disease patients has provided evidence of a potential role in bowel inflammation. METHODS: Adamdec1(-/-) mice were exposed to dextran sodium sulphate or infected orally with Citrobacter rodentium or Salmonella typhimurium The clinical response was monitored. RESULTS: The loss of Adamdec1 rendered mice more susceptible to the induction of bacterial and chemical induced colitis, as evidenced by increased neutrophil infiltration, greater IL-6 and IL-1β secretion, more weight loss and increased mortality. In the absence of Adamdec1, greater numbers of Citrobacter rodentium were found in the spleen, suggestive of a breakdown in mucosal immunity which resulted in bacteraemia. CONCLUSION: In summary, Adamdec1 protects the bowel from chemical and bacterial insults, failure of which may predispose to Crohn's disease

    Characterisation of feline renal cortical fibroblast cultures and their transcriptional response to transforming growth factor beta 1

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    Chronic kidney disease (CKD) is common in geriatric cats, and the most prevalent pathology is chronic tubulointerstitial inflammation and fibrosis. The cell type predominantly responsible for the production of extra-cellular matrix in renal fibrosis is the myofibroblast, and fibroblast to myofibroblast differentiation is probably a crucial event. The cytokine TGF-β1 is reportedly the most important regulator of myofibroblastic differentiation in other species. The aim of this study was to isolate and characterise renal fibroblasts from cadaverous kidney tissue of cats with and without CKD, and to investigate the transcriptional response to TGF-β1

    Sibling interaction as a facilitator for talent development in sport

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    While current research has begun to address parental influences on talent development in sport, sibling interaction remains relatively under-examined. Therefore, this study aimed to explore the underpinning mechanisms through which sibling interaction impacts on talent development. Retrospective phenomenological interviews were conducted with four sets of siblings (N = 9), where at least one sibling had competed to an elite level. Findings revealed several higher-order themes that impacted positively on the talented athletes’ development: regularity of interaction in sport, emotional interpersonal skills, rivalry, resilience, co-operation and separation. Separation appeared as the athlete reached elite status, suggesting that these former mechanisms primarily impact during the development phase. Such findings support and extend the sibling, elite sport and talent development literature and provide valuable insight for both practitioners and academics. Importantly, coaches should consider a sibling’s role as an important mechanism outside of the formal coaching structure for talent development

    Synthesis and Oligonucleotide Incorporation of Fluorescent Cytosine Analogue tC: a Promising Nucleic Acid Probe

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    The tricyclic cytosine, tC, is a fluorescent base analogue with excellent properties for investigating intrinsic characteristics of nucleic acid as well as interactions between nucleic acids and other molecules. Its unique fluorescence properties and insignificant influence on overall structure and dynamics of nucleic acid after incorporation makes tC particularly interesting in fluorescence resonance energy transfer and anisotropy measurements. We here describe a straightforward synthesis of the standard monomer form of tC for DNA solid-phase synthesis, the tC phosphoramidite, and its subsequent incorporation into oligonucleotides. The total synthesis of the tC phosphoramidite takes approximately 8 days and its incorporation and the subsequent oligonucleotide purification an additional day

    Search for High Mass Photon Pairs in p-pbar --> gamma-gamma-jet-jet Events at sqrt(s)=1.8 TeV

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    A search has been carried out for events in the channel p-barp --> gamma gamma jet jet. Such a signature can characterize the production of a non-standard Higgs boson together with a W or Z boson. We refer to this non-standard Higgs, having standard model couplings to vector bosons but no coupling to fermions, as a "bosonic Higgs." With the requirement of two high transverse energy photons and two jets, the diphoton mass (m(gamma gamma)) distribution is consistent with expected background. A 90(95)% C.L. upper limit on the cross section as a function of mass is calculated, ranging from 0.60(0.80) pb for m(gamma gamma) = 65 GeV/c^2 to 0.26(0.34) pb for m(gamma gamma) = 150 GeV/c^2, corresponding to a 95% C.L. lower limit on the mass of a bosonic Higgs of 78.5 GeV/c^2.Comment: 9 pages, 3 figures. Replacement has new H->gamma gamma branching ratios and corresponding new mass limit

    Search For Heavy Pointlike Dirac Monopoles

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    We have searched for central production of a pair of photons with high transverse energies in ppˉp\bar p collisions at s=1.8\sqrt{s} = 1.8 TeV using 70pb170 pb^{-1} of data collected with the D\O detector at the Fermilab Tevatron in 1994--1996. If they exist, virtual heavy pointlike Dirac monopoles could rescatter pairs of nearly real photons into this final state via a box diagram. We observe no excess of events above background, and set lower 95% C.L. limits of 610,870,or1580GeV/c2610, 870, or 1580 GeV/c^2 on the mass of a spin 0, 1/2, or 1 Dirac monopole.Comment: 12 pages, 4 figure
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