4,633 research outputs found

    KED: a deontic theorem prover

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    Deontic logic (DL) is increasingly recognized as an indispensable tool in such application areas as formal representation of legal knowledge and reasoning, formal specification of computer systems and formal analysis of database integrity constraints. Despite this acknowledgement, there have been few attempts to provide computationally tractable inference mechanisms for DL. In this paper we shall be concerned with providing a computationally oriented proof method for standard DL (SDL), i.e., normal systems of modal logic with the usual possible-worlds semantics. Because of the natural and easily implementable style of proof construction it uses, this method seems particularly well-suited for applications in the AI and Law field, and though in the present version it works for SDL only, it forms an appropriate basis for developing efficient proof methods for more expressive and sophisticated extensions of SDL

    A modal computational framework for default reasoning

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    Usually a default rule A : B/C is intended to mean that if A holds in a state of affairs a B is consistent, then C follows by default. However, C is not a necessary conclusion: different states of affairs are possible (conceivable). According to this view, Meyer and van der Hoek developed a multimodal logic, called S5P(n), for treating non-monotonic reasoning in a monotonic setting. In this paper we shall describe a proof search algorithm for S5P(n) which has been implemented as a Prolog Interpreter

    John Hunter and the origin of the term “angiogenesis”.

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    Brief communication without abstract

    Changes in T cell effector functions over an 8-year period with TNF antagonists in patients with chronic inflammatory rheumatic diseases

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    The aim of the study was to clarify the effect of long-term anti-TNF therapy on T cell function in patients with rheumatologic immune-mediated inflammatory diseases (IMID). The production of IFNγ by T cells was evaluated at baseline and after 1, 2, 4, and 8 years of anti-TNF agents by means of a QuantiFERON-TB Gold In-Tube assay. The T cell proliferation and surface co-expression of CD25/CD134 in response to phytohaemagglutinin together with the in vitro impact of anti-TNF therapy on the functional capacity of T cells were evaluated after 8 years from the onset of the biological treatment. Age-matched healthy donors were enrolled as controls. The quantitative mitogen-induced IFNγ responses significantly increased with respect to baseline at each time point, apart from the determination after 4 years. We found an increased expression of CD25/CD134 in CD4+compared to CD8+T cells both in patients and controls. The in vitro addition of anti-TNF agents induced a significant decrease of both the IFNγ response and of CD25/CD134, whereas no effect on the intensity of the proliferative response was observed. Our data provide a biological basis for the reassuring issues on the safety of long-term anti-TNF treatment in patients with IMID

    A mechanical approach to fractional non-local thermoelasticity

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    In recent years fractional di erential calculus applications have been developed in physics, chemistry as well as in engineering elds. Fractional order integrals and derivatives ex- tend the well-known de nitions of integer-order primitives and derivatives of the ordinary di erential calculus to real-order operators. Engineering applications of these concepts dealt with viscoelastic models, stochastic dy- namics as well as with the, recently developed, fractional-order thermoelasticity [3]. In these elds the main use of fractional operators has been concerned with the interpolation between the heat ux and its time-rate of change, that is related to the well-known second sound e ect. In other recent studies [2] a fractional, non-local thermoelastic model has been proposed as a particular case of the non-local, integral, thermoelasticity introduced at the mid of the seventies [1]. In this study the autors aim to provide a mechanical framework to account for fractional, non-local e ects in thermoelasticity. A mechanical model that corresponds to long-range heat ux is introduced and, on this basis, a modi ed version of the Fourier heat ux equa- tion is obtained. Such an equation involves spatial Marchaud fractional derivatives of the temperature eld as well as Riemann-Liouville fractional derivatives of the heat ux with respect to time variable to account for second sound effects

    Music in the first days of life

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    In adults, specific neural systems with right-hemispheric weighting are necessary to process pitch, melody and harmony, as well as structure and meaning emerging from musical sequences. To which extent does this neural specialization result from exposure to music or from neurobiological predispositions? We used fMRI to measure brain activity in 1 to 3 days old newborns while listening to Western tonal music, and to the same excerpts altered, so as to include tonal violations or dissonance. Music caused predominant right hemisphere activations in primary and higher-order auditory cortex. For altered music, activations were seen in the left inferior frontal cortex and limbic structures. Thus, the newborn's brain is able to plenty receive music and to figure out even small perceptual and structural differences in the music sequences. This neural architecture present at birth provides us the potential to process basic and complex aspects of music, a uniquely human capacity
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