Quantifier-Free Interpolation of a Theory of Arrays

The use of interpolants in model checking is becoming an enabling technology to allow fast and robust verification of hardware and software. The application of encodings based on the theory of arrays, however, is limited by the impossibility of deriving quantifier- free interpolants in general. In this paper, we show that it is possible to obtain quantifier-free interpolants for a Skolemized version of the extensional theory of arrays. We prove this in two ways: (1) non-constructively, by using the model theoretic notion of amalgamation, which is known to be equivalent to admit quantifier-free interpolation for universal theories; and (2) constructively, by designing an interpolating procedure, based on solving equations between array updates. (Interestingly, rewriting techniques are used in the key steps of the solver and its proof of correctness.) To the best of our knowledge, this is the first successful attempt of computing quantifier- free interpolants for a variant of the theory of arrays with extensionality

Zinc increases the effects of essential amino acids-whey protein supplements in frail elderly

Abstract: Protein undernutrition is frequent in the elderly. It contributes to the development of osteoporosis, possibly via lower IGF-I. Dietary zinc can influence IGF-I production. Objectives: To determine the influence of dietary zinc addition on IGF-I and bone turnover responses to essential amino acids-whey (EAA-W) protein supplements in frail elderly. Design and setting: A daily oral protein supplement was given to hospitalized patients for 4 weeks. On a randomized, double-blind basis, patients received either an additional 30 mg/day of zinc or control. Participants: Sixty-one hospitalized elderly aged 66.7 to 105.8, with a mini-nutritional assessment score between 17 and 24 were enrolled. Measurements: Activities of daily living; dietary intakes; serum IGF-I, IGF-BP3, CrossLaps™, osteocalcin and zinc were measured before and after 1, 2 and 4 weeks of protein supplementation. Results: Serum IGF-I rapidly increased in both groups. Zinc accelerated this increase with changes of +48.2±14.3 and +22.4±4.7% (p<.05) by 1 week, in the zinc-supplemented and control groups, respectively. Zinc significantly decreased the serum bone resorption marker CrossLaps™ by already 1 week. Activities of daily living improved by +27.0±3.1 and +18.3±4.5% in zinc-supplemented and control groups, respectively. Conclusion: In the elderly, zinc supplementation accelerated the serum IGF-I response to EAA-W protein by 1 week and decreased a biochemical marker of bone resorptio

Assessing the relative accuracy of coral heights reconstructed from drones and structure from motion photogrammetry on coral reefs

Low-altitude high-resolution aerial photographs allow for the reconstruction of structural properties of shallow coral reefs and the quantification of their topographic complexity. This study shows the scope and limitations of two-media (air/water) Structure from Motion—Multi-View Stereo reconstruction method using drone aerial photographs to reconstruct coral height. We apply this method in nine different sites covering a total area of about 7000 m2, and we examine the suitability of the method to obtain topographic complexity estimates (i.e., seafloor rugosity). A simple refraction correction and survey design allowed reaching a root mean square error of 0.1&nbsp;m for the generated digital models of the seafloor (without the refraction correction the root mean square error was 0.2&nbsp;m). We find that the complexity of the seafloor extracted from the drone digital models is slightly underestimated compared to the one measured with a traditional in situ survey method

Fixed-point elimination in the intuitionistic propositional calculus

It is a consequence of existing literature that least and greatest fixed-points of monotone polynomials on Heyting algebras-that is, the algebraic models of the Intuitionistic Propositional Calculus-always exist, even when these algebras are not complete as lattices. The reason is that these extremal fixed-points are definable by formulas of the IPC. Consequently, the $\mu$-calculus based on intuitionistic logic is trivial, every $\mu$-formula being equivalent to a fixed-point free formula. We give in this paper an axiomatization of least and greatest fixed-points of formulas, and an algorithm to compute a fixed-point free formula equivalent to a given $\mu$-formula. The axiomatization of the greatest fixed-point is simple. The axiomatization of the least fixed-point is more complex, in particular every monotone formula converges to its least fixed-point by Kleene's iteration in a finite number of steps, but there is no uniform upper bound on the number of iterations. We extract, out of the algorithm, upper bounds for such n, depending on the size of the formula. For some formulas, we show that these upper bounds are polynomial and optimal

Finitely generated free Heyting algebras via Birkhoff duality and coalgebra

Algebras axiomatized entirely by rank 1 axioms are algebras for a functor and thus the free algebras can be obtained by a direct limit process. Dually, the final coalgebras can be obtained by an inverse limit process. In order to explore the limits of this method we look at Heyting algebras which have mixed rank 0-1 axiomatizations. We will see that Heyting algebras are special in that they are almost rank 1 axiomatized and can be handled by a slight variant of the rank 1 coalgebraic methods

PARTECIPAZIONE E GRADIMENTO DI UN PERCORSO DI ACCOMPAGNAMENTO PSICOLOGICO RIVOLTO ALLE MATRICOLE DELLA FACOLTÀ DI MEDICINA

Obiettivi: valutare la partecipazione e il gradimento delle matricole che aderiscono al “Progetto Accoglienza”, un percorso di accoglienza e accompagnamento psicologico, attivo da quattro anni, presso il Corso di Laurea in Medicina e Chirurgia dell’Università degli Studi di Brescia. Metodo: il percorso si fonda sull’implementazione della figura di studenti senior (tutor), adeguatamente formati e supervisionati da docenti della Sezione di Psicologia Clinica, attraverso l’utilizzo di modalità gruppali, in accordo con specifiche metodologie utilizzate da tempo in psicologia clinica. I tutor fungono da riferimenti rassicuranti e identificatori per le matricole, che a loro volta aderiscono al progetto in modo volontario e ricevono crediti opzionali, al fine di riconoscere il valore formativo dello scambio fra studenti del primo anno e studenti senior. Per la valutazione del livello di gradimento è stato predisposto un questionario ad hoc, elaborato in parte sulla base di strumenti utilizzati nei corsi professionali in cui è previsto l’accreditamento e in parte sulla base di proposte e riflessioni fra i docenti di psicologia dell’Ateneo, che non hanno preso parte al progetto. Risultati: il numero di studenti che partecipa con regolarità al percorso di accoglienza è cresciuto nei quattro anni: da 125 a 164. Gli studenti hanno in media un’età di 19.3 anni (±1.7) e sono in prevalenza femmine. Il questionario di gradimento viene compilato in media dall’85% delle matricole coinvolte. Quasi la totalità di esse riferisce che ripeterebbe l’esperienza, anche senza crediti formativi; il 98% la consiglierebbe ad una nuova matricola. Per quanto riguarda rilevanza, efficacia e utilità del percorso rispetto alle proprie esigenze formative, anche in questo caso la maggior parte degli studenti riporta una valutazione positiva. Conclusioni: i dati raccolti mostrano un gradimento medio-alto, che si mantiene costante negli anni. Si ritiene che tale percorso possa fornire un aiuto concreto per fronteggiare le difficoltà associate all’ingresso nell’Università. Fra gli indicatori di efficacia di consimili interventi nel lungo periodo, riteniamo utile la ricaduta in termini di prevenzione del drop out e dell’ allungamento temporale del corso di studi

What's Decidable About Sequences?

We present a first-order theory of sequences with integer elements, Presburger arithmetic, and regular constraints, which can model significant properties of data structures such as arrays and lists. We give a decision procedure for the quantifier-free fragment, based on an encoding into the first-order theory of concatenation; the procedure has PSPACE complexity. The quantifier-free fragment of the theory of sequences can express properties such as sortedness and injectivity, as well as Boolean combinations of periodic and arithmetic facts relating the elements of the sequence and their positions (e.g., "for all even i's, the element at position i has value i+3 or 2i"). The resulting expressive power is orthogonal to that of the most expressive decidable logics for arrays. Some examples demonstrate that the fragment is also suitable to reason about sequence-manipulating programs within the standard framework of axiomatic semantics.Comment: Fixed a few lapses in the Mergesort exampl

How to assess appearance distress and motivation in plastic surgery candidates: Italian validation of Derriford Appearance Scale 59 (DAS 59)

The Derriford Appearance Scale (DAS) 59 was specifically designed to measure psychosocial adjustment in patients with appearance problems. Previous studies using the DAS59 have proven it to be a reliable method of assessing the appearance-related quality of life after plastic surgery procedures. The aim of this study was to develop a valid and reliable Italian version of the DAS59