Backward Reachability of Array-based Systems by SMT solving: Termination and Invariant Synthesis

The safety of infinite state systems can be checked by a backward reachability procedure. For certain classes of systems, it is possible to prove the termination of the procedure and hence conclude the decidability of the safety problem. Although backward reachability is property-directed, it can unnecessarily explore (large) portions of the state space of a system which are not required to verify the safety property under consideration. To avoid this, invariants can be used to dramatically prune the search space. Indeed, the problem is to guess such appropriate invariants. In this paper, we present a fully declarative and symbolic approach to the mechanization of backward reachability of infinite state systems manipulating arrays by Satisfiability Modulo Theories solving. Theories are used to specify the topology and the data manipulated by the system. We identify sufficient conditions on the theories to ensure the termination of backward reachability and we show the completeness of a method for invariant synthesis (obtained as the dual of backward reachability), again, under suitable hypotheses on the theories. We also present a pragmatic approach to interleave invariant synthesis and backward reachability so that a fix-point for the set of backward reachable states is more easily obtained. Finally, we discuss heuristics that allow us to derive an implementation of the techniques in the model checker MCMT, showing remarkable speed-ups on a significant set of safety problems extracted from a variety of sources.Comment: Accepted for publication in Logical Methods in Computer Scienc

Zinc increases the effects of essential amino acids-whey protein supplements in frail elderly

Abstract: Protein undernutrition is frequent in the elderly. It contributes to the development of osteoporosis, possibly via lower IGF-I. Dietary zinc can influence IGF-I production. Objectives: To determine the influence of dietary zinc addition on IGF-I and bone turnover responses to essential amino acids-whey (EAA-W) protein supplements in frail elderly. Design and setting: A daily oral protein supplement was given to hospitalized patients for 4 weeks. On a randomized, double-blind basis, patients received either an additional 30 mg/day of zinc or control. Participants: Sixty-one hospitalized elderly aged 66.7 to 105.8, with a mini-nutritional assessment score between 17 and 24 were enrolled. Measurements: Activities of daily living; dietary intakes; serum IGF-I, IGF-BP3, CrossLaps™, osteocalcin and zinc were measured before and after 1, 2 and 4 weeks of protein supplementation. Results: Serum IGF-I rapidly increased in both groups. Zinc accelerated this increase with changes of +48.2±14.3 and +22.4±4.7% (p<.05) by 1 week, in the zinc-supplemented and control groups, respectively. Zinc significantly decreased the serum bone resorption marker CrossLaps™ by already 1 week. Activities of daily living improved by +27.0±3.1 and +18.3±4.5% in zinc-supplemented and control groups, respectively. Conclusion: In the elderly, zinc supplementation accelerated the serum IGF-I response to EAA-W protein by 1 week and decreased a biochemical marker of bone resorptio

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

Identificação por "Multiplex PCR" do sorotipo monofásico e atípico Salmonella enterica subsp. enterica sorotipo 1,4,[5],12:i:-, no Estado de São Paulo, Brasil: freqüência e resistência antimicrobiana

Salmonella spp. are the etiologic agents of salmonellosis, a worldwide spread zoonoses causing foodborne outbreaks and clinical diseases. By serological identification, Salmonella enterica subsp. enterica serotype 1,4,[5],12:i:- accounted for 8.8% of human and 1.6% of nonhuman Salmonella strains isolated in São Paulo State, during 1991-2000. A total of 28.6% of them amplified a fragment corresponding to H:1,2 (flagellar phase two) through PCR analysis and were further assigned as S. Typhimurium. Antimicrobial resistance was detected in 36.3% of the 369 PCR-negative strains tested, including the multiresistance to ampicillin, chloramphenicol, sulfonamides, tetracycline, and streptomycin.Salmonella spp. é o agente etiológico da salmonelose, zoonose mundialmente distribuída e responsável por surtos de doenças transmitidas por alimentos e doenças clínicas. Sorologicamente, Salmonella enterica subsp. enterica sorotipo 1,4,[5],12:i:- correspondeu a 8,8% e 1,6% das cepas de Salmonella de origem humana e não-humana, respectivamente, isoladas no Estado de São Paulo, no decênio 1991-2000. Aproximadamente 28,6% destas cepas amplificaram o fragmento correspondente a H:1,2 (fase flagelar dois) em testes de PCR e foram, então, identificadas como S. Typhimurium. Das 369 cepas negativas em PCR, 36,3% apresentou resistência antimicrobiana, incluindo multirresistência a ampicilina, cloranfenicol, sulfonamidas, tetraciclina e estreptomicina

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

Mental disorders and work integration: a retrospective study in a northern italian town.

OBJECTIVES: THE PRESENT STUDY WAS CONDUCTED IN A VOCATIONAL INTEGRATION SERVICE OF A NORTHERN ITALIAN TOWN WITH TWO MAJOR AIMS: to assess vocational integration programs undertaken from 1(st) January 2004 to 1(st) January 2007; and to identify job tenure-associated predictors. METHODS: This is a retrospective study; we collected data such as gender, age, duration, type and outcome of the vocational integration program, and number of interventions performed by the vocational integration service. Self-report questionnaires were also used to assess the satisfaction of users, caregivers, practitioners, and of the company contacts involved in the study. RESULTS: The service has enrolled 84 users during the observation period. Out of these users, 64.3% of them still had their jobs after three years. Users, caregivers and company contacts expressed high levels of satisfaction for the support received by the vocational integration service. The company expressed less satisfaction for the collaboration received by the Departments of Mental Health (DMHs) that coached the users. The only variable associated to the outcome was the number of interventions that the users received before their placement on the job. CONCLUSIONS: Despite all the limits of this study, its results show that the chance of taking advantage of a supported job placement service has likely proven itself effective in helping people with mental disorders to obtain and maintain a competitive employment. Our results, however, also point to the necessity of implementing newer strategies meant to develop a greater integration among all services dealing with mentally ill people

PARTECIPAZIONE E GRADIMENTO DI UN PERCORSO DI ACCOMPAGNAMENTO PSICOLOGICO RIVOLTO ALLE MATRICOLE DELLA FACOLTÀ DI MEDICINA

Obiettivi: valutare la partecipazione e il gradimento delle matricole che aderiscono al “Progetto Accoglienza”, un percorso di accoglienza e accompagnamento psicologico, attivo da quattro anni, presso il Corso di Laurea in Medicina e Chirurgia dell’Università degli Studi di Brescia. Metodo: il percorso si fonda sull’implementazione della figura di studenti senior (tutor), adeguatamente formati e supervisionati da docenti della Sezione di Psicologia Clinica, attraverso l’utilizzo di modalità gruppali, in accordo con specifiche metodologie utilizzate da tempo in psicologia clinica. I tutor fungono da riferimenti rassicuranti e identificatori per le matricole, che a loro volta aderiscono al progetto in modo volontario e ricevono crediti opzionali, al fine di riconoscere il valore formativo dello scambio fra studenti del primo anno e studenti senior. Per la valutazione del livello di gradimento è stato predisposto un questionario ad hoc, elaborato in parte sulla base di strumenti utilizzati nei corsi professionali in cui è previsto l’accreditamento e in parte sulla base di proposte e riflessioni fra i docenti di psicologia dell’Ateneo, che non hanno preso parte al progetto. Risultati: il numero di studenti che partecipa con regolarità al percorso di accoglienza è cresciuto nei quattro anni: da 125 a 164. Gli studenti hanno in media un’età di 19.3 anni (±1.7) e sono in prevalenza femmine. Il questionario di gradimento viene compilato in media dall’85% delle matricole coinvolte. Quasi la totalità di esse riferisce che ripeterebbe l’esperienza, anche senza crediti formativi; il 98% la consiglierebbe ad una nuova matricola. Per quanto riguarda rilevanza, efficacia e utilità del percorso rispetto alle proprie esigenze formative, anche in questo caso la maggior parte degli studenti riporta una valutazione positiva. Conclusioni: i dati raccolti mostrano un gradimento medio-alto, che si mantiene costante negli anni. Si ritiene che tale percorso possa fornire un aiuto concreto per fronteggiare le difficoltà associate all’ingresso nell’Università. Fra gli indicatori di efficacia di consimili interventi nel lungo periodo, riteniamo utile la ricaduta in termini di prevenzione del drop out e dell’ allungamento temporale del corso di studi

Apropiaciones y usos del suelo y las viviendas urbanas: agentes, prácticas y lógicas intervinientes. La segregación y el derecho a la ciudad en el Área Metropolitana de Mendoza, Argentina

El actual capitalismo globalizado cuenta con un modelo neoliberal de producción de las ciudades caracterizado por situaciones de apropiación y uso de los espacios que llevan al aislamiento y la segregación de amplios sectores de la población en el que la privación y la exclusión residencial son una constante.El Área Metropolitana de Mendoza (AMM) en Argentina forma parte de ese escenario. Su actual realidad urbana plantea la necesidad de pensar y discutir la inclusión a los procesos de construcción del AMM de los grupos que residen en hábitats no adecuados en presencia de una multiplicidad de exclusiones. Esto implica por un lado, comprender cómo el contexto económico y político de las últimas décadas ha favorecido la aparición de espacios informales urbanos, y por tanto, analizar cómo se articula de manera dialéctica la estructura social y la estructura espacial. Por otro lado, identificar a los agentes participantes, fundamentalmente residentes de barrios y asentamientos precarios privados de su derecho a participar en la construcción de la ciudad, el Estado y el sector privado. También, caracterizar y comprender las lógicas intervinientes en los procesos de apropiación y construcción espacial; y por último, identificar y analizar las prácticas o estrategias que toman lugar tanto en la denominada ciudad formal como en la informal, desde una perspectiva relacional de los condicionamientos materiales y simbólicos, así como coyunturales e históricos. Se espera avanzar en la comprensión de los actuales procesos de segregación en el contexto de las dinámicas sociales y urbanas del AMM en particular y de las ciudades argentinas y latinoamericanas en general.Fil: Ghilardi, Matías R.. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto de Estudios Históricos, Económicos, Sociales e Internacionales. Instituto Multidisciplinario de Estudios Sociales Contemporáneos; ArgentinaFil: Dalla Torre, Julieta. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Saavedra 15. Instituto de Estudios Históricos, Económicos, Sociales e Internacionales. Instituto Multidisciplinario de Estudios Sociales Contemporáneos; ArgentinaCongreso Internacional CONTESTED_CITIES: Del conflicto urbano a la construcción de alternativas, diálogos críticosMadridEspañaUniversidad Autónoma de Madri

SEGREGAÇÃO SÓCIO-ESPACIAL NA PERIFERIA DA GRANDE MENDOZA, ARGENTINA. As estratégias dos excluídos urbanos

A lógica que prevalece nos territórios das cidades nas últimas décadas tem suas causas na terceira chamada globalização, que começou na década de 1970, graças às novas tecnologias e da revolução econômica que tentaram fundir todas as economias em uma economia de "single mundo". Neste novo cenário, o papel do Estado não corresponde com o da sociedade industrial, mas melhorado seu enfraquecimento, aumentando políticas liberais. Estas mudanças têm consequências em diferentes níveis e são observados na morfologia urbana e como as cidades se expandem no espaço, impactando a nossa forma de interagir socialmente. Neste trabalho, analisar os atuais processos de segregação sócio-espacial, cujo metropolitana periferias cenário. Em particular, centra-se na Área Metropolitana de Mendoza, Argentina. Ele procura explicar os elementos materiais e simbólicos que mostram esses processos, bem como as estratégias da comunidade de atores sociais que exigem a inclusão na cidade formal