Quantifier-Free Interpolation of a Theory of Arrays

The use of interpolants in model checking is becoming an enabling technology to allow fast and robust verification of hardware and software. The application of encodings based on the theory of arrays, however, is limited by the impossibility of deriving quantifier- free interpolants in general. In this paper, we show that it is possible to obtain quantifier-free interpolants for a Skolemized version of the extensional theory of arrays. We prove this in two ways: (1) non-constructively, by using the model theoretic notion of amalgamation, which is known to be equivalent to admit quantifier-free interpolation for universal theories; and (2) constructively, by designing an interpolating procedure, based on solving equations between array updates. (Interestingly, rewriting techniques are used in the key steps of the solver and its proof of correctness.) To the best of our knowledge, this is the first successful attempt of computing quantifier- free interpolants for a variant of the theory of arrays with extensionality

Fixed-point elimination in the intuitionistic propositional calculus

It is a consequence of existing literature that least and greatest fixed-points of monotone polynomials on Heyting algebras-that is, the algebraic models of the Intuitionistic Propositional Calculus-always exist, even when these algebras are not complete as lattices. The reason is that these extremal fixed-points are definable by formulas of the IPC. Consequently, the $\mu$-calculus based on intuitionistic logic is trivial, every $\mu$-formula being equivalent to a fixed-point free formula. We give in this paper an axiomatization of least and greatest fixed-points of formulas, and an algorithm to compute a fixed-point free formula equivalent to a given $\mu$-formula. The axiomatization of the greatest fixed-point is simple. The axiomatization of the least fixed-point is more complex, in particular every monotone formula converges to its least fixed-point by Kleene's iteration in a finite number of steps, but there is no uniform upper bound on the number of iterations. We extract, out of the algorithm, upper bounds for such n, depending on the size of the formula. For some formulas, we show that these upper bounds are polynomial and optimal

Molecular dynamics simulation of aqueous solutions of 26-unit segments of p(NIPAAm) and of p(NIPAAm) "doped" with amino acid based comonomers

We have performed 75-ns molecular dynamics (MD) simulations of aqueous solutions of a 26-unit NIPAAm oligomer at two temperatures, 302 and 315 K, below and above the experimentally determined lower critical solution temperature (LCST) of p(NIPAAm). We have been able to show that at 315 K the oligomer assumes a compact form, while it keeps a more extended form at 302 K. A similar behavior has been demonstrated for a similar NIPAAm oligomer, where two units had been substituted by methacryloyl-l-valine (MAVA) comonomers, one of them being charged and one neutral. For another analogous oligomer, where the same units had been substituted by methacryloyl-l-leucine (MALEU) comonomers, no transition from the extended to the more compact conformation has been found within the same simulation time. Statistical analysis of the trajectories indicates that this transition is related to the dynamics of the oligomer backbone, and to the formation of intramolecular hydrogen bonds and water-bridges between distant units of the solute. In the MAVA case, we have also evidenced an important role of the neutral MAVA comonomer in stabilizing the compact coiled structure. In the MALEU case, the corresponding comonomer is not equally efficacious and, possibly, is even hindering the readjustment of the oligomer backbone. Finally the self-diffusion coefficient of water molecules surrounding the oligomers at the two temperatures for selected relevant times is observed to characteristically depend on the distance from the solute molecules

Finitely generated free Heyting algebras via Birkhoff duality and coalgebra

Algebras axiomatized entirely by rank 1 axioms are algebras for a functor and thus the free algebras can be obtained by a direct limit process. Dually, the final coalgebras can be obtained by an inverse limit process. In order to explore the limits of this method we look at Heyting algebras which have mixed rank 0-1 axiomatizations. We will see that Heyting algebras are special in that they are almost rank 1 axiomatized and can be handled by a slight variant of the rank 1 coalgebraic methods

Admissible Bases Via Stable Canonical Rules

We establish the dichotomy property for stable canonical multi-conclusion rules for IPC, K4, and S4. This yields an alternative proof of existence of explicit bases of admissible rules for these logics

Creation of museums as strategy for preservation of the fossil heritage of Araripe sedimentary basin in Pernambuco, NE, Brazil

O Araripe pernambucano tem excelentes exposições de rochas da Formação Santana, Bacia Sedimentar do Araripe (PE, CE e PI), reconhecida internacionalmente pelos fósseis de vertebrados, preservados em concreções, considerados entre os mais importantes do supercontinente Gondwana (110 Ma). Embora a região tenha excelente potencial para coleta e estudos paleontológicos, facilitada pela extração a céu aberto da gipsita (Polo Gesseiro do Araripe), não existem ações de preservação do patrimônio fossilífero. Dado a vocação mineira e o potencial paleontológico, a região torna-se relevante para desenvolvimento de programas, projetos e ações que promovam os recursos naturais para uso educacional, turístico, inclusão social e sustentabilidade. Propõe-se a criação de museus paleontológicos nos municípios do Araripe pernambucano, como estratégia de uso sustentável desses recursos para geração de cultura e renda para a região, ao mesmo tempo em que se preserva para as gerações futuras a “memória paleobiológica da Terra”, retratada nos nossos fósseis.The Araripe Basin portion located in the Pernambuco state of Brazil has excellent Santana Formation outcrops. This internationally known unit has provided some of the most important concretion preserved vertebrate fossils of the Lower Cretaceous (~110 Ma) Gondwana. Although this region has its potential for fossil collecting eased by the gypsum extraction in surface mines (known as the ‘Araripe Plast Pole’), there are currently no fossil Patrimony preservation actions in the area. Given both the mining and paleontological potentials of these localities it is relevant to develop programmes, projects, and measures to promote its natural resources for educational, touristic, social, and sustainable porpuses. Here we propose the creation of paleontological museums in some of the Araripe municipalities within the Pernambuco state. These museums will be strategic for the sustainability of these resources to generate culture and profit for this region. These museums will also preserve the ‘Earth’s paleobiological memory’ by protecting our fossils for future generations.Agradecemos ao Conselho Nacional de Desenvolvimento Científico e Tecnológico do Brasil/CNPq, pela bolsa de produtividade de pesquisa 303071/2014-1 e o projeto de pesquisa 401748/2010, a Pró-reitora de Extensão- PROEXT-UFPE e a FUNCULTURA, Processo 0756/2014. Sinceros agradecimentos também são devidos a prefeitura do Munícipio de Exu, ao Departamento Nacional de Produção Mineral-DNPM e ao Sindicato da Indústria do Gesso de Pernambuco/SINDUGESSO, pelo apoio no desenvolvimento da pesquisa.info:eu-repo/semantics/publishedVersio

Violent behavior of patients living in psychiatric residential facilities: A comparison of male patients with different violence histories

People with severe mental disorders and a history of violence are often seen as a difficult-to-manage segment of the population. In addition, this group is usually characterized by a high risk of crime recidivism, and poor compliance with community and aftercare programs. To investigate a sample of male patients living in Residential Facilities (RFs) with a history of violent behavior against people and to compare their characteristics with those of never-violent residents; to analyze the associations between aggressive behaviors in the last two years and a history of previous violence; and, to assess the predictors of aggressive behaviors. This study is part of a prospective observational cohort study which involved 23 RFs in Northern Italy. A comprehensive set of sociodemographic, clinical, and treatment-related information was gathered, and standardized assessments were administered to each participant. Also a detailed assessment of aggressive behaviors in the past two years was carried out. The study involved 268 males: 81 violent and 187 never-violent. Compared to never-violent patients, violent patients were younger, with a higher proportion of personality disorders, and have displayed an increased number of aggressive behaviors in the last two years. The presence of a history of violent behavior in the past significantly increases the probability of committing aggressive acts in the future

New results on rewrite-based satisfiability procedures

Program analysis and verification require decision procedures to reason on theories of data structures. Many problems can be reduced to the satisfiability of sets of ground literals in theory T. If a sound and complete inference system for first-order logic is guaranteed to terminate on T-satisfiability problems, any theorem-proving strategy with that system and a fair search plan is a T-satisfiability procedure. We prove termination of a rewrite-based first-order engine on the theories of records, integer offsets, integer offsets modulo and lists. We give a modularity theorem stating sufficient conditions for termination on a combinations of theories, given termination on each. The above theories, as well as others, satisfy these conditions. We introduce several sets of benchmarks on these theories and their combinations, including both parametric synthetic benchmarks to test scalability, and real-world problems to test performances on huge sets of literals. We compare the rewrite-based theorem prover E with the validity checkers CVC and CVC Lite. Contrary to the folklore that a general-purpose prover cannot compete with reasoners with built-in theories, the experiments are overall favorable to the theorem prover, showing that not only the rewriting approach is elegant and conceptually simple, but has important practical implications.Comment: To appear in the ACM Transactions on Computational Logic, 49 page

Selective inhibition of tropomyosin-receptor-kinase A (TrkA) reduces pain and joint damage in two rat models of inflammatory arthritis

Background: Inflammation is an essential component of arthritis pain. Nerve growth factor (NGF) plays a key role in acute and chronic pain states especially those associated with inflammation. NGF acts through tropomyosin-receptor-kinase A (TrkA). NGF blockade has reduced arthritis pain in clinical trials. We explored the mechanisms within the joint which may contribute to the analgesic effects of NGF by selectively inhibiting TrkA in carrageenan-induced or collagen-induced joint pain behaviour. The goal of the current study was to elucidate whether inflammation is central to the efficacy for NGF blockade. Methods: Rats were injected in their left knees with 2 % carrageenan or saline. Collagen-induced arthritis (CIA) was induced by intradermal injections of a mixture of bovine type II collagen (0.2 mg) and incomplete Freund’s adjuvant (0.2 mg). Oral doses (30 mg/kg) of AR786 or vehicle control were given twice daily after arthritis induction. Ibuprofen-treated (35 mg/kg, orally, once daily) rats with CIA were used as positive analgesic controls. Pain behaviour was measured as hind-limb weight-bearing asymmetry and hind-paw withdrawal thresholds to von Frey hair stimulation (carrageenan synovitis), or withdrawal to joint compression using a Randall Selitto device (CIA). Inflammation was measured as increased knee joint diameter and by histopathological analysis. Results: Intra-articular injections of carrageenan or induction of CIA was each associated with pain behaviour and synovial inflammation. Systemic administration of the TrkA inhibitor AR786 reduced carrageenan-induced or CIA-induced pain behaviour to control values, and inhibited joint swelling and histological evidence of synovial inflammation and joint damage. Conclusions: By using two models of varying inflammation we demonstrate for the first time that selective inhibition of TrkA may reduce carrageenan-induced or CIA-induced pain behaviour in rats, in part through potentially inhibiting synovial inflammation, although direct effects on sensory nerves are also likely. Our observations suggest that inflammatory arthritis causes pain and the presence of inflammation is fundamental to the beneficial effects (reduction in pain and pathology) of NGF blockade. Further research should determine whether TrkA inhibition may ameliorate human inflammatory arthritis

The effect of service satisfaction and spiritual well-being on the quality of life of patients with schizophrenia.

Quality of life (QOL) has been considered an important outcome measure in psychiatric research and determinants of QOL have been widely investigated. We aimed at detecting predictors of QOL at baseline and at testing the longitudinal interrelations of the baseline predictors with QOL scores at a 1-year follow-up in a sample of patients living in Residential Facilities (RFs). Logistic regression models were adopted to evaluate the association between WHOQoL-Bref scores and potential determinants of QOL. In addition, all variables significantly associated with QOL domains in the final logistic regression model were included by using the Structural Equation Modeling (SEM). We included 139 patients with a diagnosis of schizophrenia spectrum. In the final logistic regression model level of activity, social support, age, service satisfaction, spiritual well-being and symptoms' severity were identified as predictors of QOL scores at baseline. Longitudinal analyses carried out by SEM showed that 40% of QOL follow-up variability was explained by QOL at baseline, and significant indirect effects toward QOL at follow-up were found for satisfaction with services and for social support. Rehabilitation plans for people with schizophrenia living in RFs should also consider mediators of change in subjective QOL such as satisfaction with mental health services