281 research outputs found

    Comparison of PBO solvers in a dependency solving domain

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    Linux package managers have to deal with dependencies and conflicts of packages required to be installed by the user. As an NP-complete problem, this is a hard task to solve. In this context, several approaches have been pursued. Apt-pbo is a package manager based on the apt project that encodes the dependency solving problem as a pseudo-Boolean optimization (PBO) problem. This paper compares different PBO solvers and their effectiveness on solving the dependency solving problem.Comment: In Proceedings LoCoCo 2010, arXiv:1007.083

    SAT based Enforcement of Domotic Effects in Smart Environments

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    The emergence of economically viable and efficient sensor technology provided impetus to the development of smart devices (or appliances). Modern smart environments are equipped with a multitude of smart devices and sensors, aimed at delivering intelligent services to the users of smart environments. The presence of these diverse smart devices has raised a major problem of managing environments. A rising solution to the problem is the modeling of user goals and intentions, and then interacting with the environments using user defined goals. `Domotic Effects' is a user goal modeling framework, which provides Ambient Intelligence (AmI) designers and integrators with an abstract layer that enables the definition of generic goals in a smart environment, in a declarative way, which can be used to design and develop intelligent applications. The high-level nature of domotic effects also allows the residents to program their personal space as they see fit: they can define different achievement criteria for a particular generic goal, e.g., by defining a combination of devices having some particular states, by using domain-specific custom operators. This paper describes an approach for the automatic enforcement of domotic effects in case of the Boolean application domain, suitable for intelligent monitoring and control in domotic environments. Effect enforcement is the ability to determine device configurations that can achieve a set of generic goals (domotic effects). The paper also presents an architecture to implement the enforcement of Boolean domotic effects, and results obtained from carried out experiments prove the feasibility of the proposed approach and highlight the responsiveness of the implemented effect enforcement architectur

    Synthesis, stability and zeolitic behavior of Ύ­ALn3F10,xH2O and γ­ThLn2F10,H2O phases (Ln = lanthanide)

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    Two series of hydrated fluorides have been prepared by a “chimie douce” process. For the first family, more than twenty five compounds of ή-ALn3F10,xH2O (A+ = alkaline ions, NH4+, H3O+ and Ln = lanthanide) have been prepared. They crystallize in the Fd [[3 with combining macron]] m space group (a ≈ 15.4 Å and Z = 16) and are isotypic with ή-(H3O)Yb3F10,xH2O (x = 1). The diamond-type structure of these phases (diamond stacking of octahedral units of antiprisms, called UOA[8]), creates cavities and tunnels where the water molecules can move. The second family, γ-ThLn2F10,H2O (Ln3+ = Er3+, Dy3+ and Yb3+) results from the substitution of Ln3+ and A+ by a tetravalent cation. The new compound γ-ThEr2F10,H2O (Fm [[3 with combining macron]] m space group, a = 10.739(1) Å and Z = 8) is isotypic with γ-KYb3F10. Water molecules are located inside the tunnels (8c sites) of a CCP stacking of UOA[8] through which they can move. For both series, the thermal stability and the zeolitic behaviour, studied by DTA/TGA and X-ray thermodiffractometry, are reported and a low zeolitic water capacity, around 2–4% in mass, is observed

    Invasive pulmonary aspergillosis in chronic obstructive pulmonary disease: an emerging fungal pathogen

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    ABSTRACTAcute invasive pulmonary aspergillosis occurs predominantly in immunocompromised hosts, with increasing numbers of cases of invasive aspergillosis among patients with chronic obstructive pulmonary disease (COPD) being reported. Among 13 cases of invasive aspergillosis diagnosed in COPD patients admitted to the intensive care unit with acute respiratory distress, the only risk factor for invasive fungal infection was corticosteroid treatment. Invasive aspergillosis should be suspected in COPD patients receiving steroid treatment who have extensive pulmonary infiltrates. Survival depends on rapid diagnosis and early appropriate treatment. A decrease or interruption of steroid treatment should be considered as part of the overall therapeutic strategy

    Confinement and Low Adhesion Induce Fast Amoeboid Migration of Slow Mesenchymal Cells

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    The mesenchymal-amoeboid transition (MAT) was proposed as a mechanism for cancer cells to adapt their migration mode to their environment. While the molecular pathways involved in this transition are well documented, the role of the microenvironment in the MAT is still poorly understood. Here, we investigated how confinement and adhesion affect this transition. We report that, in the absence of focal adhesions and under conditions of confinement, mesenchymal cells can spontaneously switch to a fast amoeboid migration phenotype. We identified two main types of fast migration-one involving a local protrusion and a second involving a myosin-II-dependent mechanical instability of the cell cortex that leads to a global cortical flow. Interestingly, transformed cells are more prone to adopt this fast migration mode. Finally, we propose a generic model that explains migration transitions and predicts a phase diagram of migration phenotypes based on three main control parameters: confinement, adhesion, and contractility

    Quorum-sensing activity and related virulence factor expression in clinically pathogenic isolates of Pseudomonas aeruginosa

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    AbstractRespiratory isolates of Pseudomonas aeruginosa were collected from 58 critically-ill patients with ventilator-associated pneumonia. Expression of elastase and pyocyanin was assessed semi-quantitatively, while quorum-sensing activity was assessed by quantifying the levels of the autoinducers N-3-oxododecanoyl-L-homoserine lactone (C12-HSL) and N-butanoyl-L-homoserine lactone (C4-HSL). Correlations were sought between quorum-sensing activity and the expression of these two virulence factors, and all results were compared to those obtained with the laboratory reference strains PA103, a strain defective in quorum-sensing, and PAO1, a functional quorum-sensing strain. More than two-thirds of clinically pathogenic isolates had increased levels of elastase and/or pyocyanin, and high quorum-sensing activity, as assessed by autoinducer levels. However, a strong correlation between quorum-sensing activity and virulence factor production was revealed only for elastase and not for pyocyanin (C12-HSL/elastase, r = 0.7, p 2 × 10−9; C4-HSL/elastase, r = 0.7, p 2 × 10−9). These data suggest that the pathogenicity of P. aeruginosa isolates from critically-ill patients with ventilator-associated pneumonia is caused, at least in part, by an increase in elastase production regulated by quorum-sensing, while increased pyocyanin production in these isolates may be regulated predominantly by mechanisms other than quorum-sensing

    Direct and inverse measurement of thin films magnetostriction

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    Two techniques of measurements of thin film magnetostriction are compared: direct, when changes of the substrate curvature caused by the film magnetization are controlled, and inverse ("indirect"), when the modification of the magnetic anisotropy induced by the substrate deformation (usually bending) is measured. We demonstrate how both the elastic strength of the substrate and the effective magneto-mechanical coupling between the substrate deformation and magnetic anisotropy of the film depend on different conditions of bending. Equations to be used for magnetostriction value determination in typical cases are given and critical parameters for the corresponding approximations are identified.Comment: 13 pages, 10 figures, 1 table, submitted to JMM

    Generation of spatial antibunching with free propagating twin beams

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    We propose and implement a novel method to produce a spatial anti-bunched field with free propagating twin beams from spontaneous parametric down-conversion. The method consists in changing the spatial propagation by manipulating the transverse degrees of freedom through reflections of one of the twin beams. Our method use reflective elements eliminating losses from absorption by the objects inserted in the beams.Comment: Submitted for publication in Phys. Rev.
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