Heuristic Backtracking Algorithms for SAT

In recent years backtrack search SAT solvers have been the subject of dramatic improvements. These improvements allowed SAT solvers to successfully replace BDDs in many areas of formal verification, and also motivated the development of many new challenging problem instances, many of which too hard for the current generation of SAT solvers. As a result, further improvements to SAT technology are expected to have key consequences in formal verification. The objective of this paper is to propose heuristic approaches to the backtrack step of backtrack search SAT solvers, with the goal of increasing the ability of the SAT solver to search different parts of the search space. The proposed heuristics to the backtrack step are inspired by the heuristics proposed in recent years for the branching step of SAT solvers, namely VSIDS and some of its improvements. The preliminary experimental results are promising, and motivate the integration of heuristic backtracking in state-of-the-art SAT solvers. 1

Colheita e conservação de cerejas.

Este texto resulta dos conhecimentos que foram sendo consolidados no decorrer do Projecto PAMAF 6006 "Optimização das operações de pós colheita par um aumento da rentabilidade na comercialização de Cerejas". Este Projecto reúne colaboradores do ISA (DAIAT e DPAA), do IST (DEM e DEQ), da ESACB (Fitotecnia), da DRAEDM e da DRATM. Os seus principais objectivos são: 1. Aumentar o tempo de vida útil da cereja: Melhorar procedimentos na colheita para minimizar os danos mecânicos e térmicos nos frutos; Utilização de frio de forma eficaz (pré arrefecimento e conservação a temperatura baixa). 2. Introdução de mais valias na comercialização de cerejas: Calibragem; Embalagem; Desenvolvimento de produtos para uso do refugo das operações de selecção e calibragem. Este texto irá incidir na discussão de alguns aspectos a considerar na marcação da data de colheita e na conservação de cereja para o mercado de frescos.info:eu-repo/semantics/publishedVersio

Congenital lobular capillary hemangioma of the nasal cavity of an infant - A rare case report

Introdução: O hemangioma capilar lobular (HCL), originalmente denominado como granuloma piogénico, é uma lesão vascular benigna de crescimento rápido de etiologia desconhecida, com uma distinta arquitectura microscópica lobular, que afecta a pele e mucosa. Embora o HCL da cabeça e pescoço não seja incomum, a sua ocorrência na fossa nasal é pouco frequente, e ainda mais raro em crianças. Material e métodos: Estudo retrospectivo de caso clínico de um lactente com uma massa na fossa nasal direita diagnosticada como HCL, utilizando o método descritivo. Resultados: Esta é uma revisão da história de um lactente com 54 dias de idade referenciado ao nosso hospital por obstrução nasal severa causada por uma massa da fossa nasal direita. A criança apresentava dificuldade respiratória desde o nascimento, que se foi agravando progressivamente à medida que a massa aumentava de tamanho. Esta estava a ser responsável pelo abaulamento do lado direito da pirâmide nasal e septo e pelo aparecimento de edema periorbitário à direita. Após remoção da massa através de cirurgia endoscópica nasal, foi feito o diagnóstico histológico de HCL. Conclusões: Os autores encontraram apenas a descrição de um caso na literatura de um HCL congénito da fossa nasal num lactente. Embora raro, o HCL deve ser incluído no diagnóstico diferencial de massas das fossas nasais na população pediátrica.info:eu-repo/semantics/publishedVersio

Volatiles and refratories in solar analogs: no terrestial planet connection

We have analysed very high-quality HARPS and UVES spectra of 95 solar analogs, 24 hosting planets and 71 without detected planets, to search for any possible signature of terrestial planets in the chemical abundances of volatile and refractory elements with respect to the solar abundances. We demonstrate that stars with and without planets in this sample show similar mean abundance ratios, in particular, a sub-sample of 14 planet-host and 14 "single" solar analogs in the metallicity range 0.14<[Fe/H]<0.36. In addition, two of the planetary systems in this sub-sample, containing each of them a super-Earth-like planet with masses in the range ~ 7-11 Earth masses, have different volatile-to-refratory abundance ratios to what would be expected from the presence of a terrestial planets. Finally, we check that after removing the Galactic chemical evolution effects any possible difference in mean abundances, with respect to solar values, of refratory and volatile elements practically dissappears.Comment: 2 pages, 2 figures, to appear in the proceedings of the 276th IAU Symposium "The Astrophysics of Planetary Systems

Tau as the converging protein between chronic stress and Alzheimer's disease synaptic pathology

Background: Alzheimer's disease (AD) is a multifactorial neurodegenerative disorder with a complex physiopathology and still undefined initiators. Several risk factors have been suggested for AD with recent evidence supporting an etiopathogenic role of chronic environmental stress and glucocorticoids (GCs, stress hormones) in the development of the disease. Indeed, both AD and chronic stress are associated with neuronal atrophy, synaptic loss and cognitive impairment. Our previous studies have demonstrated the aggravating role of stress and GCs on AD pathology, including Tau hyperphosphorylation and aggregation and cognitive deficits in various AD models. In light of the suggested involvement of Tau missorting in AD synaptotoxity and the dual cytoplasmic and synaptic role of Tau, our recent studies focused on the possible role of Tau in the underlying cascades of stress/GC neuronal malfunction/atrophy in wild type animals by monitoring the intracellular localization of Tau and its phosphorylation status in different cellular compartments. Summary: Biochemical, ultrastructural, behavioral and neurostructural analysis have helped demonstrate that prolonged GC administration leads to dendritic remodeling and spine atrophy and loss in the rat hippocampus triggering Tau missorting at hippocampal synapses with the participation of specific phosphorylated Tau isoforms in this synaptic accumulation. Key Messages: The above findings suggest that Tau plays an essential role in mediating the neurodegenerative effects of stress and GCs towards the development of AD pathology. In addition, they highlight the involvement of Tau missorting in mechanism(s) of synaptic atrophy, beyond AD adding to our limited knowledge of the mechanisms through which stress causes brain pathology

Enhancing Fault / Intrusion Tolerance through Design and Configuration Diversity

Fault/intrusion tolerance is usually the only viable way of improving the system dependability and security in the presence of continuously evolving threats. Many of the solutions in the literature concern a specific snapshot in the production or deployment of a fault-tolerant system and no immediate considerations are made about how the system should evolve to deal with novel threats. In this paper we outline and evaluate a set of operating systems’ and applications’ reconfiguration rules which can be used to modify the state of a system replica prior to deployment or in between recoveries, and hence increase the replicas chance of a longer intrusion-free operation