An irregular filter model

AbstractIn this paper we introduce a new filter model, which is of a kind that has escaped investigation up to now: it is induced by an intersection type theory generated in a non-standard way, by a preorder which puts into relation an atom with an arrow type, without equating them. We study the domain-theoretic implications of this choice, that are not trivial: in order to describe this filter model a new category is introduced and a special purpose functor defined. The filter model is then characterized as the initial algebra of the functor

Tiered Objects

We investigate the foundations of reasoning over infinite data structures by means of set-theoretical structures arising in the sheaf-theoretic semantics of higher-order intuitionistic logic. Our approach focuses on a natural notion of tiering involving an operation of restriction of elements to levels forming a complete Heyting algebra. We relate these tiered objects to final coalgebras and initial algebras of a wide class of endofunctors of the category of sets, and study their order and convergence properties. As a sample application, we derive a general proof principle for tiered objects

A fixed-point theorem in a category of compact metric spaces

AbstractVarious results appear in the literature for deriving existence and uniqueness of fixed points for endofunctors on categories of complete metric spaces. All these results are proved for contracting functors which satisfy some further requirements, depending on the category in question.Following a new kind of approach, based on the notion of η-isometry, we show that the sole hypothesis of contractivity is enough for proving existence and uniqueness of fixed points for endofunctors on the category of compact metric spaces and embedding-projection pairs

Antimitochondrial antibody -M2 positive autoimmune hepatitis during standard of care for chronic hepatitis C.

The current standard of care (SoC) for chronic hepatitis C, i.e. the combination of a pegylated-interferon (PEG-IFN) with ribavirin (RBV), may activate underlying autoimmune conditions. Particularly, interferon (IFN) has been known to induce or exacerbate autoimmune hepatitis (AIH) and primary biliary cirrhosis (PBC) in hepatitis C virus patients. We describe a severe, acute-onset antimitochondrial antibody (AMA)-M2 positive AIH appearing during the last weeks of SoC in a woman with chronic hepatitis C and no previous history of autoimmunity, and resolving on protracted steroids. In this context, the relevance of the characterization of the immunoglobulin isotype of portal plasma cells for a more appropriate diagnosis of autoimmune liver diseases can be emphasized

Studio di fattibilità. Sistema per il monitoraggio in continuo del particolato emesso dal camino di un impianto FCC CO-Boiler di una raffineria

Questo studio di fattibilità nasce dalla richiesta della Commissione IPPC (Integrated Pollution Prevention and Control) di far implementare, al sistema di gestione delle emissioni gassose, un sistema per il monitoraggio in continuo per la quantificazione delle polveri emesse dal camino di un impianto FCC CO-Boiler (Fluid Catalytic Cracking) di una raffineria. Per verificare la fattibilità tecnica di questa richiesta sono stati studiati sia i dati storici di monitoraggio delle emissione gassose del camino, per l’individuazione delle condizioni fluido dinamiche, sia i principi di funzionamento delle tecniche strumentali in commercio e usate per scopi simili. Da questi dati si sono ricavate le condizioni fluido dinamiche dell'effluente gassoso e la distribuzione granulometrica del particolato emesso in atmosfera, nelle tre seguenti classi granulometriche dia>10, 10<dia<2.5, dia<2.5 micrometri, da cui sono stati successivamente desunti i parametri di progetto. Dallo studio delle tecnologie già esistenti per il monitoraggio delle polveri è stato individuato un sistema, conforme alle condizioni del camino, che vede l'uso contemporaneo di una sonda elettrodinamica e di una sonda laser scattering. L'impiego di queste due tecniche strumentali è necessaria al fine di assicurare una corretta misurazione del particolato nelle diverse condizioni di funzionamento del camino

Finite mixture model-based classification of a complex vegetation system

To propose a Finite Mixture Model (FMM) as an additional approach for classifying large datasets of georeferenced vegetation plots from complex vegetation systems. Study area: The Italian peninsula including the two main islands (Sicily and Sardinia), but excluding the Alps and the Po plain. Methods: We used a database of 5,593 georeferenced plots and 1,586 vascular species of forest vegetation, created in TURBOVEG by storing published and unpublished phytosociological plots collected over the last 30 years. The plots were classified according to species composition and environmental variables using a FMM. Classification results were compared with those obtained by TWINSPAN algorithm. Groups were characterized in terms of ecological parameters, dominant and diagnostic species using the fidelity coefficient. Interpretation of resulting forest vegetation types was supported by a predictive map, produced using discriminant functions on environmental predictors, and by a non\u2010metric multidimensional scaling ordination. Results: FMM clustering obtained 24 groups that were compared with those from TWINSPAN, and similarities were found only at a higher classification level corresponding to the main orders of the Italian broadleaf forest vegetation: Fagetalia sylvaticae, Carpinetalia betuli, Quercetalia pubescenti-petraeae and Quercetalia ilicis. At lower syntaxonomic level, these 24 groups were referred to alliances and sub-alliances. Conclusions: Despite a greater computational complexity, FMM appears to be an effective alternative to the traditional classification methods through the incorporation of modelling in the classificatory process. This allows classification of both the co-occurrence of species and environmental factors so that groups are identified not only on their species composition, as in the case of TWINSPAN, but also on their specific environmental niche