Deductive Verification of Unmodified Linux Kernel Library Functions

This paper presents results from the development and evaluation of a deductive verification benchmark consisting of 26 unmodified Linux kernel library functions implementing conventional memory and string operations. The formal contract of the functions was extracted from their source code and was represented in the form of preconditions and postconditions. The correctness of 23 functions was completely proved using AstraVer toolset, although success for 11 functions was achieved using 2 new specification language constructs. Another 2 functions were proved after a minor modification of their source code, while the final one cannot be completely proved using the existing memory model. The benchmark can be used for the testing and evaluation of deductive verification tools and as a starting point for verifying other parts of the Linux kernel.Comment: 18 pages, 2 tables, 6 listings. Accepted to ISoLA 2018 conference. Evaluating Tools for Software Verification trac

Contributions to knowledge on the maturation and fertility of the common octopus Octopus vulgaris Cuvier, 1797 on the Portuguese coast

The aim of the present study was to study the reproduction of the common octopus Octopus vulgaris Cuvier, 1797 at three locations on the mainland Portuguese coast. The results showed a higher occurrence of mature females in May-July and November at both Cascais and Santa Luzia, and in February and November at Viana do Castelo. Mature males were found year round. The fertility of females from Santa Luzia was higher (average of 230 000 oocytes), which could be due to this location's more favourable environmental conditions. At Cascais, the average was 140 000 oocytes, and at Viana do Castelo, 120 000. Our results could be useful in drawing up more suitable management measures for octopus Portuguese stocks.El objetivo es el estudio de la reproducción del pulpo común Octopus vulgaris Cuvier 1797 en tres localidades de la costa continental portuguesa. Los resultados demostraron un mayor registro de hembras maduras en mayo-julio y noviembre en Cascais y Santa Luzia, y en febrero y noviembre en Viana do Castelo. Hay machos maduros durante todo el año. La fecundidad de las hembras es mayor en Santa Luzia (con un promedio de 230 000 oocitos), lo que estaría asociado a las condiciones ambientales más favorables de esta localidad. En Cascais y Viana do Castelo el promedio fue de 140 000 y 120 000 oocitos, respectivamente. Estos datos podrán ser útiles para la propuesta de medidas más adecuadas para la gestión de las poblaciones de esta especie en las costas portuguesas.Instituto Español de Oceanografí

Cosmological constant constraints from observation-derived energy condition bounds and their application to bimetric massive gravity

Among the various possibilities to probe the theory behind the recent accelerated expansion of the universe, the energy conditions (ECs) are of particular interest, since it is possible to confront and constrain the many models, including different theories of gravity, with observational data. In this context, we use the ECs to probe any alternative theory whose extra term acts as a cosmological constant. For this purpose, we apply a model-independent approach to reconstruct the recent expansion of the universe. Using Type Ia supernova, baryon acoustic oscillations and cosmic-chronometer data, we perform a Markov Chain Monte Carlo analysis to put constraints on the effective cosmological constant $\Omega^0_{\rm eff}$. By imposing that the cosmological constant is the only component that possibly violates the ECs, we derive lower and upper bounds for its value. For instance, we obtain that $0.59 < \Omega^0_{\rm eff} < 0.91$ and $0.40 < \Omega^0_{\rm eff} < 0.93$ within, respectively, $1\sigma$ and $3\sigma$ confidence levels. In addition, about 30\% of the posterior distribution is incompatible with a cosmological constant, showing that this method can potentially rule it out as a mechanism for the accelerated expansion. We also study the consequence of these constraints for two particular formulations of the bimetric massive gravity. Namely, we consider the Visser's theory and the Hassan and Roses's massive gravity by choosing a background metric such that both theories mimic General Relativity with a cosmological constant. Using the $\Omega^0_{\rm eff}$ observational bounds along with the upper bounds on the graviton mass we obtain constraints on the parameter spaces of both theories.Comment: 11 pages, 4 figures, 1 tabl

Ecogeographical Variation in Skull Shape of South-American Canids: Abiotic or Biotic Processes?

Species morphological changes can be mutually influenced by environmental or biotic factors, such as competition. South American canids represent a quite recent radiation of taxa that evolved forms very disparate in phenotype, ecology and behaviour. Today, in the central part of South America there is one dominant large species (the maned wolf, Chrysocyon brachyurus) that directly influence sympatric smaller taxa via interspecific killing. Further south, three species of similar sized foxes (Lycalopex spp.) share the same habitats. Such unique combination of taxa and geographic distribution makes South American dogs an ideal group to test for the simultaneous impact of climate and competition on phenotypic variation. Using geometric morphometrics, we quantified skull size and shape of 431 specimens belonging to the eight extant South American canid species: Atelocynus microtis, Cerdocyon thous, Ch. brachyurus, Lycalopex culpaeus, L. griseus, L. gymnocercus, L. vetulus and Speothos venaticus. South American canids are significantly different in both skull size and shape. The hypercarnivorous bush dog is mostly distinct in shape from all the other taxa while a degree of overlap in shape—but not size—occurs between species of the genus Lycalopex. Both climate and competition impacts interspecific morphological variation. We identified climatic adaptations as the main driving force of diversification for the South American canids. Competition has a lower degree of impact on their skull morphology although it might have played a role in the past, when canid community was richer in morphotypes

Observational Constraints on Visser's Cosmological Model

Theories of gravity for which gravitons can be treated as massive particles have presently been studied as realistic modifications of General Relativity, and can be tested with cosmological observations. In this work, we study the ability of a recently proposed theory with massive gravitons, the so-called Visser theory, to explain the measurements of luminosity distance from the Union2 compilation, the most recent Type-Ia Supernovae (SNe Ia) dataset, adopting the current ratio of the total density of non-relativistic matter to the critical density ($\Omega_m$) as a free parameter. We also combine the SNe Ia data with constraints from Baryon Acoustic Oscillations (BAO) and CMB measurements. We find that, for the allowed interval of values for $\Omega_m$, a model based on Visser's theory can produce an accelerated expansion period without any dark energy component, but the combined analysis (SNe Ia + BAO + CMB) shows that the model is disfavored when compared with $\Lambda$CDM model.Comment: 6 pages, 4 figure

Teachers’ ideas about children’s participation within Portuguese early childhood education settings

This study investigated teachers’ ideas about children's right to participate in ECE. Participants were 59 teachers, aged between 26 and 60 years old (M = 43.07 years, SD = 8.58), all female, from 59 ECE classrooms from 24 randomly selected ECE centres located in the metropolitan area of Lisbon. Teacher's ideas were collected using a qualitative interview specifically designed for the purpose. Based on content analysis, multiple correspondence analysis, and cluster analysis, we identified profiles of teachers’ ideas and clusters of teachers. Results suggest four teacher profiles: Teachers motivation, Teachers’ conditioned responsibility, Children's benefits, and Context dependent. Profiles were significantly associated with years of professional experience and type of institution. Teachers’ age was significantly different across profiles. Findings provide insights to fuller understand teachers’ positioning about this right.info:eu-repo/semantics/acceptedVersio