207 research outputs found

    On an interpretation of safe recursion in light affine logic

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    AbstractWe introduce a subalgebra BC− of Bellantoni and Cook's safe-recursion function algebra BC. Functions of the subalgebra have safe arguments that are non-contractible (i.e non-duplicable). We propose a definition of safe and normal variables in light affine logic (LAL), and show that BC− is the largest subalgebra that is interpretable in LAL, relative to that definition. Though BC− itself is not PF complete, there are extensions of it (by additional schemes for defining functions with safe arguments) that are, and are still interpretable in LAL and so preserve PF closure. We focus on one such which is BC− augmented by a definition-by-cases construct and a restricted form of definition-by-recursion scheme over safe arguments. As a corollary we obtain a new proof of the PF completeness of LAL

    Pengukuran Kristalinitas Silika berdasarkan Metode Difraktrometer Sinar-X

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    Sari. Mineralogi dan derajat kristalinitas mineral silika non- dan mikrokristalin dapat ditentukan dengan metode difraktometer sinar-X, yaitu dengan mengukur lebar peak atau hump pada setengah intensitas-maksimum difraksi pada posisi sekitar 4 Ã…. Hasil optimum pengukuran kristalinitas diperoleh bila sampel silika kering berukuran butir 75 hingga 106 μm dipreparasi pada cetakan aluminium dan dianalis mulai 10 hingga 40°2θ dengan kecepatan goniometer 0,6°2θ/menit dan interval pencatatan 0,01°. Prosedur seperti ini akan mempunyai kesalahan tidak lebih dari 0,3°2θ. Measurement of Silica Crystallinity Using X-Ray Diffraction MethodAbstract. Mirralogy and the degree of crystallinity of non- and microcrystalline silica could be determined using the X-ray diffraction method, i.e. by measuring the half-width peak or hump at about 4 Ã…. The optimum and most reproducible results were obtained when dry silica sample powder having a grain size of 75 to 106 μm was prepared at the aluminium holder and scanned from 10 to 40°2θ using goniometer speed of 0.6°2θ and a step size of 0.01°. This procedure will give an experimental error less than 0.3°2θ

    Integer polyhedra for program analysis

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    Polyhedra are widely used in model checking and abstract interpretation. Polyhedral analysis is effective when the relationships between variables are linear, but suffers from imprecision when it is necessary to take into account the integrality of the represented space. Imprecision also arises when non-linear constraints occur. Moreover, in terms of tractability, even a space defined by linear constraints can become unmanageable owing to the excessive number of inequalities. Thus it is useful to identify those inequalities whose omission has least impact on the represented space. This paper shows how these issues can be addressed in a novel way by growing the integer hull of the space and approximating the number of integral points within a bounded polyhedron

    Symbolic Backwards-Reachability Analysis for Higher-Order Pushdown Systems

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    Higher-order pushdown systems (PDSs) generalise pushdown systems through the use of higher-order stacks, that is, a nested "stack of stacks" structure. These systems may be used to model higher-order programs and are closely related to the Caucal hierarchy of infinite graphs and safe higher-order recursion schemes. We consider the backwards-reachability problem over higher-order Alternating PDSs (APDSs), a generalisation of higher-order PDSs. This builds on and extends previous work on pushdown systems and context-free higher-order processes in a non-trivial manner. In particular, we show that the set of configurations from which a regular set of higher-order APDS configurations is reachable is regular and computable in n-EXPTIME. In fact, the problem is n-EXPTIME-complete. We show that this work has several applications in the verification of higher-order PDSs, such as linear-time model-checking, alternation-free mu-calculus model-checking and the computation of winning regions of reachability games

    Digital Cognitive Behavioral Therapy for Insomnia in Women With Chronic Migraines

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    Objective/Background: Insomnia commonly co-occurs with chronic migraines (CM). Non-pharmacological treatments for insomnia in CM patients remain understudied. This is a proof-of-concept study, which aims to evaluate the feasibility, acceptability, and preliminary efficacy of a digital cognitive behavioral therapy for insomnia (dCBT-I) for individuals with CM and insomnia (CM-I) in the United States. Methods: We recruited 42 females with CM-I symptoms from a U.S.-based observational cohort and from the general population via advertisements. Within a multiple baseline design, participants were randomized to receive dCBT-I after 2, 4, or 6 weeks of completing baseline sleep diaries. DCBT-I was scrutinized against benchmarks for completion rates (≥90% to complete dCBT-I), acceptability (≥80% to find dCBT-I acceptable), and posttreatment changes in insomnia symptoms (≥50% indicating a clinically relevant improvement in their insomnia symptoms). As a secondary measure, we also reported percentage of individuals reverting to episodic migraines. Results: Out of 42 randomized, 35 (83.3%) completed dCBT-I within the 12 weeks provided. Of these completers, 33 (94.3%) reported being satisfied (n = 16) or very satisfied (n = 17) with treatment. Additionally, 65.7% of completers responded to treatment as per universally accepted criteria for insomnia. Lastly, 34% of completers reverted from CM to episodic migraine. Conclusion: This study provides evidence for the feasibility and acceptability of dCBT-I in patients with CM-I complaints. Effects of improving insomnia and migraines were suggested. These results indicate that a randomized controlled trial is needed to determine the efficacy of dCBT-I in CM patients

    Towards a canonical classical natural deduction system

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    This paper studies a new classical natural deduction system, presented as a typed calculus named \lml. It is designed to be isomorphic to Curien-Herbelin's calculus, both at the level of proofs and reduction, and the isomorphism is based on the correct correspondence between cut (resp. left-introduction) in sequent calculus, and substitution (resp. elimination) in natural deduction. It is a combination of Parigot's ΝΟ\lambda\mu-calculus with the idea of ``coercion calculus'' due to Cervesato-Pfenning, accommodating let-expressions in a surprising way: they expand Parigot's syntactic class of named terms. This calculus aims to be the simultaneous answer to three problems. The first problem is the lack of a canonical natural deduction system for classical logic. \lml is not yet another classical calculus, but rather a canonical reflection in natural deduction of the impeccable treatment of classical logic by sequent calculus. The second problem is the lack of a formalization of the usual semantics of Curien-Herbelin's calculus, that explains co-terms and cuts as, respectively, contexts and hole-filling instructions. The mentioned isomorphism is the required formalization, based on the precise notions of context and hole-expression offered by \lml. The third problem is the lack of a robust process of ``read-back'' into natural deduction syntax of calculi in the sequent calculus format, that affects mainly the recent proof-theoretic efforts of derivation of Ν\lambda-calculi for call-by-value. An isomorphic counterpart to the QQ-subsystem of Curien-Herbelin's-calculus is derived, obtaining a new Ν\lambda-calculus for call-by-value, combining control and let-expressions.Fundação para a Ciência e a Tecnologia (FCT

    Global microRNA profiling in human urinary exosomes reveals novel disease biomarkers and cellular pathways for Autosomal Dominant Polycystic Kidney Disease

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    MicroRNAs (miRNAs) play an important role in regulating gene expression in health and disease but their role in modifying disease expression in Autosomal Dominant Polycystic Kidney Disease (ADPKD) remains uncertain. Here, we profiled human urinary exosome miRNA by global small RNA-sequencing in an initial discovery cohort of seven patients with ADPKD with early disease (eGFR over 60ml/min/1.73m2), nine with late disease (eGFR under 60ml/min/1.73m2), and compared their differential expression with six age and sex matched healthy controls. Two kidney-enriched candidate miRNA families were identified (miR-192/miR-194-2 and miR-30) and selected for confirmatory testing in a 60 patient validation cohort by quantitative polymerase chain reaction. We confirmed that miR-192-5p, miR-194- 5p, miR-30a-5p, miR-30d-5p and miR-30e-5p were significantly downregulated in patient urine exosomes, in murine Pkd1 cystic kidneys and in human PKD1 cystic kidney tissue. All five miRNAs showed significant correlations with baseline eGFR and ultrasound-determined mean kidney length and improved the diagnostic performance (area under the curve) of mean kidney length for the rate of disease progression. Finally, inverse correlations of these two miRNA families with increased expression in their predicted target genes in patient PKD1 cystic tissue identified dysregulated pathways and transcriptional networks including novel interactions between miR-194-5p and two potentially relevant candidate genes, PIK3R1 and ANO1. Thus, our results identify a subset of urinary exosomal miRNAs that could serve as novel biomarkers of disease progression and suggest new therapeutic targets in ADPKD

    Untyped Recursion Schemes and Infinite Intersection Types

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    Abstract. A new framework for higher-order program verification has been recently proposed, in which higher-order functional programs are modelled as higher-order recursion schemes and then model-checked. As recursion schemes are essentially terms of the simply-typed lambda-calculus with recursion and tree constructors, however, it was not clear how the new framework applies to programs written in languages with more advanced type systems. To circumvent the limitation, this paper introduces an untyped version of recursion schemes and develops an in-finite intersection type system that is equivalent to the model checking of untyped recursion schemes, so that the model checking can be re-duced to type checking as in recent work by Kobayashi and Ong for typed recursion schemes. The type system is undecidable but we can obtain decidable subsets of the type system by restricting the shapes of intersection types, yielding a sound (but incomplete in general) model checking algorithm.

    A Burkholderia pseudomallei toxin inhibits helicase activity of translation factor eIF4A

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    The structure of BPSL1549, a protein of unknown function from Burkholderia pseudomallei, reveals a similarity to Escherichia coli cytotoxic necrotizing factor 1. We found that BPSL1549 acted as a potent cytotoxin against eukaryotic cells and was lethal when administered to mice. Expression levels of bpsl1549 correlate with conditions expected to promote or suppress pathogenicity. BPSL1549 promotes deamidation of glutamine-339 of the translation initiation factor eIF4A, abolishing its helicase activity and inhibiting translation. We propose to name BPSL1549 Burkholderia lethal factor 1
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