On Deciding Local Theory Extensions via E-matching

Satisfiability Modulo Theories (SMT) solvers incorporate decision procedures for theories of data types that commonly occur in software. This makes them important tools for automating verification problems. A limitation frequently encountered is that verification problems are often not fully expressible in the theories supported natively by the solvers. Many solvers allow the specification of application-specific theories as quantified axioms, but their handling is incomplete outside of narrow special cases. In this work, we show how SMT solvers can be used to obtain complete decision procedures for local theory extensions, an important class of theories that are decidable using finite instantiation of axioms. We present an algorithm that uses E-matching to generate instances incrementally during the search, significantly reducing the number of generated instances compared to eager instantiation strategies. We have used two SMT solvers to implement this algorithm and conducted an extensive experimental evaluation on benchmarks derived from verification conditions for heap-manipulating programs. We believe that our results are of interest to both the users of SMT solvers as well as their developers

Invariant Synthesis for Incomplete Verification Engines

We propose a framework for synthesizing inductive invariants for incomplete verification engines, which soundly reduce logical problems in undecidable theories to decidable theories. Our framework is based on the counter-example guided inductive synthesis principle (CEGIS) and allows verification engines to communicate non-provability information to guide invariant synthesis. We show precisely how the verification engine can compute such non-provability information and how to build effective learning algorithms when invariants are expressed as Boolean combinations of a fixed set of predicates. Moreover, we evaluate our framework in two verification settings, one in which verification engines need to handle quantified formulas and one in which verification engines have to reason about heap properties expressed in an expressive but undecidable separation logic. Our experiments show that our invariant synthesis framework based on non-provability information can both effectively synthesize inductive invariants and adequately strengthen contracts across a large suite of programs

Association between vitamin D insufficiency and tuberculosis in a vietnamese population

<p>Abstract</p> <p>Background</p> <p>Recent <it>in vitro </it>evidence suggests a link between vitamin D status and the risk of tuberculosis (TB). This study sought to examine the association between vitamin D status, parathyroid hormone (PTH) and the risk of TB in a Vietnamese population.</p> <p>Methods</p> <p>The study was designed as a matched case-control study, which involved 166 TB patients (113 men and 53 women), who were age-and-sex matched with 219 controls (113 men and 106 women). The average age of men and women was 49 and 50, respectively. TB was diagnosed by the presence of acid-fast bacilli on smears from sputum, and the isolation of <it>M. tuberculosis</it>. All patients were hospitalized for treatment in a TB specialist hospital. Controls were randomly drawn from the general community within the Ho Chi Minh, Vietnam. 25-hydroxyvitamin D [25(OH)D] and PTH was measured prior to treatment by an electrochemiluminescence immunoassay (ECLIA) on a Roche Elecsys. A serum level of 25(OH)D below 30 ng/mL was deemed to be vitamin D insufficient.</p> <p>Results</p> <p>The prevalence of vitamin D insufficiency was 35.4% in men with TB and 19.5% in controls (<it>P </it>= 0.01). In women, there were no significant differences in serum 25(OH)D and serum PTH levels between TB patients and controls. The prevalence of vitamin D insufficiency in women with TB (45.3%) was not significantly different from those without TB (47.6%; <it>P </it>= 0.91). However, in both genders, serum calcium levels in TB patients were significantly lower than in non-TB individuals. Smoking (odds ratio [OR] 1.25; 95% confidence interval [CI] 1.10 - 14.7), reduced 25(OH)D (OR per standard deviation [SD]: 1.14; 95% CI 1.07 - 10.7) and increased PTH (OR per SD 1.13; 95% CI 1.05 - 10.4) were independently associated with increased risk of TB in men.</p> <p>Conclusion</p> <p>These results suggest that vitamin D insufficiency was a risk factor for tuberculosis in men, but not in women. However, it remains to be established whether the association is a causal relationship.</p

Latent tuberculosis infection, tuberculin skin test and vitamin D status in contacts of tuberculosis patients: a cross-sectional and case-control study

<p>Abstract</p> <p>Background</p> <p>Deficient serum vitamin D levels have been associated with incidence of tuberculosis (TB), and latent tuberculosis infection (LTBI). However, to our knowledge, no studies on vitamin D status and tuberculin skin test (TST) conversion have been published to date. The aim of this study was to estimate the associations of serum 25-hydroxyvitamin D₃(25[OH]D) status with LTBI prevalence and TST conversion in contacts of active TB in Castellon (Spain).</p> <p>Methods</p> <p>The study was designed in two phases: cross-sectional and case-control. From November 2009 to October 2010, contacts of 42 TB patients (36 pulmonary, and 6 extra-pulmonary) were studied in order to screen for TB. LTBI and TST conversion cases were defined following TST, clinical, analytic and radiographic examinations. Serum 25(OH)D levels were measured by electrochemiluminescence immunoassay (ECLIA) on a COBAS^®410 ROCHE^®analyzer. Logistic regression models were used in the statistical analysis.</p> <p>Results</p> <p>The study comprised 202 people with a participation rate of 60.1%. Only 20.3% of the participants had a sufficient serum 25(OH)D (≥ 30 ng/ml) level. In the cross-sectional phase, 50 participants had LTBI and no association between LTBI status and serum 25(OH)D was found. After 2 months, 11 out of 93 negative LTBI participants, without primary prophylaxis, presented TST conversion with initial serum 25(OH)D levels: a:19.4% (7/36): < 20 ng/ml, b:12.5% (4/32):20-29 ng/ml, and c:0%(0/25) ≥ 30 ng/ml. A sufficient serum 25(OH)D level was a protector against TST conversion a: Odds Ratio (OR) = 1.00; b: OR = 0.49 (95% confidence interval (CI) 0.07-2.66); and c: OR = 0.10 (95% CI 0.00-0.76), trends p = 0.019, adjusted for high exposure and sputum acid-fast bacilli positive index cases. The mean of serum level 25(OH)D in TST conversion cases was lower than controls,17.5 ± 5.6 ng/ml versus 25.9 ± 13.7 ng/ml (p = 0.041).</p> <p>Conclusions</p> <p>The results suggest that sufficient serum 25(OH)D levels protect against TST conversion.</p

Molecular dynamics simulations of non-equilibrium systems

Peer reviewe

Exposição corporal do cliente no atendimento das necessidades básicas em UTI: incidentes críticos relatados por enfermeiras Exposición corporal de pacientes en la atención a las necesidades básicas en UTI: los incidentes críticos relatados por enfermeros Physical exposure of clients in care for basic needs at an ICU: critical incidents reported by nurses

Objetivou-se identificar e analisar situações envolvendo a exposição corporal e invasão da privacidade do cliente, inerentes à assistência em UTI. A população consistiu em 15 enfermeiras de UTIs para adultos, em Maringá-PR. Empregou-se a Técnica do Incidente Crítico (TIC), obtendo-se 30 relatos, 15 positivos e 15 negativos, extraindo-se 22 incidentes críticos positivos e 30 negativos. Esses foram compilados em 6 categorias, optando-se por apresentar e discutir a categoria Necessidades básicas. Os comportamentos da equipe de saúde constituíram 5 categorias e dos clientes 3. As conseqüências para a equipe de saúde e para os clientes compuseram 4 categorias. Verificou-se melhor preparo da enfermagem para contornar problemas relacionados ao atendimento dessas necessidades, que equipe e clientes manifestam os mesmos sentimentos, que os aspectos que garantem a qualidade da assistência são proteção da intimidade, respeito, confiança e orientação, e que desproteção da intimidade do cliente prejudica a qualidade da assistência.<br>La finalidad de esta investigación fue identificar y analizar las situaciones que implicaban la exposición corporal y la invasión de la privacidad del cliente, inherentes a la atención en la UTI. La población consistió en 15 enfermeros de UTIs de atención al adulto en Maringá-PR, Brasil. Fue utilizada la Técnica del Incidente Crítico (TIC), resultando en 30 informes, 15 positivos y 15 negativos, extrayéndose 22 incidentes críticos positivos y 30 negativos. Estos fueron agrupados en 6 categorías, optándose por la presentación y discusión de la categoría necesidades básicas. Los comportamientos del equipo de la salud se agruparon en 5 categorías y aquellos de los clientes en 3. Las consecuencias para el equipo de la salud y los clientes fueron agrupadas en 4 categorías. Verificamos que el equipo de enfermería está mejor preparado para esquivar los problemas relacionados a la atención de estas necesidades, que el equipo y los clientes manifiestan los mismos sentimientos, que los aspectos que garantizan la calidad de la atención son protección de la intimidad del cliente, respecto, confianza y orientación, y que desprotección de la intimidad del cliente perjudica la calidad de la atención.<br>This study aimed to identify and analyze situations involving the physical exposure and invasion of clients' privacy, which are inherent to ICU care. The population consisted of 15 adult ICU nurses in Maringá-PR, Brazil. The Critical Incident Technique was used (CIT), resulting in 30 reports, 15 of which were positive and 15 negative. From these, 22 positive and 30 negative critical incidents were extracted. These were compiled in 6 categories. We chose to present and to discuss the category Basic needs. The health team's behavior constituted 5 categories and the clients' behavior 3. Consequences for health team and clients corresponded to 4 categories. The results revealed that the nursing team is better prepared to handle problems related to care for basic needs; that team and clients disclose the same feelings; that privacy protection, respect, confidence and guidance guarantee the quality of care and that not protecting clients' intimacy impaired care quality