56 research outputs found

    Weak MSO: Automata and Expressiveness Modulo Bisimilarity

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    We prove that the bisimulation-invariant fragment of weak monadic second-order logic (WMSO) is equivalent to the fragment of the modal μ\mu-calculus where the application of the least fixpoint operator μp.φ\mu p.\varphi is restricted to formulas φ\varphi that are continuous in pp. Our proof is automata-theoretic in nature; in particular, we introduce a class of automata characterizing the expressive power of WMSO over tree models of arbitrary branching degree. The transition map of these automata is defined in terms of a logic FOE1∞\mathrm{FOE}_1^\infty that is the extension of first-order logic with a generalized quantifier ∃∞\exists^\infty, where ∃∞x.ϕ\exists^\infty x. \phi means that there are infinitely many objects satisfying ϕ\phi. An important part of our work consists of a model-theoretic analysis of FOE1∞\mathrm{FOE}_1^\infty.Comment: Technical Report, 57 page

    Model theory of monadic predicate logic with the infinity quantifier

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    This paper establishes model-theoretic properties of ME∞, a variation of monadic first-order logic that features the generalised quantifier ∃ ∞ (‘there are infinitely many’). We will also prove analogous versions of these results in the simpler setting of monadic first-order logic with and without equality (ME and M, respectively). For each logic L∈ { M, ME, ME∞} we will show the following. We provide syntactically defined fragments of L characterising four different semantic properties of L-sentences: (1) being monotone and (2) (Scott) continuous in a given set of monadic predicates; (3) having truth preserved under taking submodels or (4) being truth invariant under taking quotients. In each case, we produce an effectively defined map that translates an arbitrary sentence φ to a sentence φp belonging to the corresponding syntactic fragment, with the property that φ is equivalent to φp precisely when it has the associated semantic property. As a corollary of our developments, we obtain that the four semantic properties above are decidable for L-sentences

    Short-term effects of a nicotine-free e-cigarette compared to a traditional cigarette in smokers and non-smokers

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    BACKGROUND: A few studies have assessed the short-term effects of low-dose nicotine e-cigarettes, while data about nicotine-free e-cigarettes (NF e-cigarettes) are scanty. Concerns have been expressed about the use of NF e-cigarettes, because of the high concentrations of propylene glycol and other compounds in the e-cigarette vapor. METHODS: This laboratory-based study was aimed to compare the effects of ad libitum use of a NF e-cigarette or and a traditional cigarette for 5 min in healthy adult smokers (n\u2009=\u200910) and non-smokers (n\u2009=\u200910). The main outcome measures were pulmonary function tests, fraction of exhaled nitric oxide (FeNO) and fractional concentration of carbon monoxide (FeCO) in exhaled breath. RESULTS: The traditional cigarette induced statistically significant increases in FeCO in both smokers and non-smokers, while no significant changes were observed in FeNO. In non-smokers, the traditional cigarette induced a significant decrease from baseline in FEF75 (81 %\u2009\ub1\u200935 % vs 70.2 %\u2009\ub1\u200928.2 %, P\u2009=\u20090.013), while in smokers significant decreases were observed in FEF25 (101.3 %\u2009\ub1\u200916.4 % vs 93.5 %\u2009\ub1\u200931.7 %, P\u2009=\u20090.037), FEV1 (102.2 %\u2009\ub1\u20099.5 % vs 98.3 %\u2009\ub1\u200910 %, P\u2009=\u20090.037) and PEF (109.5 %\u2009\ub1\u200914.6 % vs 99.2 %\u2009\ub1\u200917.5 %, P\u2009=\u20090.009). In contrast, the only statistically significant effects induced by the NF e-cigarette in smokers were reductions in FEV1 (102.2 %\u2009\ub1\u20099.5 % vs 99.5\u2009\ub1\u20097.6 %, P\u2009=\u20090.041) and FEF25 (103.4 %\u2009\ub1\u200916.4 % vs 94.2 %\u2009\ub1\u200916.2 %, P\u2009=\u20090.014). DISCUSSION: The present study demonstrated that the specific brand of NF e-cigarette utilized did not induce any majoracute effects. In contrast, several studies have shown that both traditional cigarettes and nicotine-containing e-cigarettes have acute effects on lung function. Our study expands on previous observations on the effects of NF e-cigarettes, but also for the first time describes the changes induced by smoking one traditional cigarette in a group of never smokers. CONCLUSIONS: The short-term use of the specific brand of NF e-cigarette assessed in this study had no immediate adverse effects on non-smokers and only small effects on FEV1 and FEF25 in smokers. The long-term health effects of NF e-cigarette use are unknown but worthy of further investigations. TRIAL REGISTRATION: Clinicaltrials.gov: NCT02102191

    Bleomycin electrosclerotherapy (BEST) for the treatment of vascular malformations

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    Biomedical applications of electroporation are expanding out of the field of oncology into vaccination, treatment of arrhythmias and now in the treatment of vascular malformations. Bleomycin is a widely used sclerosing agent in the treatment of various vascular malformations. The application of electric pulses in addition to bleomycin enhances the effectiveness of the drug, as demonstrated by electrochemotherapy, which utilizes bleomycin in the treatment of tumors. The same principle is used in bleomycin electrosclerotherapy (BEST). The approach seems to be effective in the treatment of low-flow (venous and lymphatic) and, potentially, even high-flow (arteriovenous) malformations. Although there are only a few published reports to date, the surgical community is interested, and an increasing number of centers are applying BEST in the treatment of vascular malformations. Within the International Network for Sharing Practices on Electrochemotherapy (InspECT) consortium, a dedicated working group has been constituted to develop standard operating procedures for BEST and foster clinical trials. By treatment standardization and successful completion of clinical trials demonstrating the effectiveness and safety of the approach, higher quality data and better clinical outcomes may be achieved
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