Model Checking Linear Logic Specifications

The overall goal of this paper is to investigate the theoretical foundations of algorithmic verification techniques for first order linear logic specifications. The fragment of linear logic we consider in this paper is based on the linear logic programming language called LO enriched with universally quantified goal formulas. Although LO was originally introduced as a theoretical foundation for extensions of logic programming languages, it can also be viewed as a very general language to specify a wide range of infinite-state concurrent systems. Our approach is based on the relation between backward reachability and provability highlighted in our previous work on propositional LO programs. Following this line of research, we define here a general framework for the bottom-up evaluation of first order linear logic specifications. The evaluation procedure is based on an effective fixpoint operator working on a symbolic representation of infinite collections of first order linear logic formulas. The theory of well quasi-orderings can be used to provide sufficient conditions for the termination of the evaluation of non trivial fragments of first order linear logic.Comment: 53 pages, 12 figures "Under consideration for publication in Theory and Practice of Logic Programming

A dual view of the 3d Heisenberg model and the abelian projection

The Heisenberg model in 3d is studied from a dual point of view. It is shown that it can have vortex configurations, carrying a conserved charge(U(1) symmetry). Vortices condens in the disordered phase. A disorder parameter \leftangle\mu\rightangle is defined dual to the magnetization \leftangle\vec n\rightangle, which signals condensation of vortices, i.e. spontaneous breaking of the dual U(1) symmetry. This study sheds light on the procedure known as abelian projection in non abelian gauge theories.Comment: LateX, 15 pages, 3 figure

Consumers' perception of farm animal welfare: an Italian and European perspective

Il lavoro esamina i risultati di alcune recenti indagini commissionate dal Direttorato Europeo per la Salute e la Protezione del Consumatore sulla percezione che i consumatori europei hanno nei confronti del benessere degli animali da reddito. Sono trattati argomenti relativi agli elementi che maggiormente influiscono sul benessere animale, alle differenze in termini di percezione del benessere animale da parte del consumatore in relazione alla specie ed alla nazione di appartenenza, alla riconoscibilit\ue0 degli alimenti ottenuti con metodi rispettosi del benessere animale e, infine, alla propensione degli acquirenti ad accettare un incremento di prezzo del prodotto (uova) ottenuto con standard di benessere animale elevati. Da tali indagini emerge come l\u2019attitudine e la conoscenza in materia di benessere animale vari notevolmente in dipendenza della nazione di origine e del grado di conoscenza diretta delle diverse realt\ue0 zootecniche da parte degli intervistati. Sebbene gli studi non forniscano una precisa definizione del concetto che il consumatore possiede di \u201cbenessere animale\u201d, l\u2019elemento che sembra massimamente qualificarlo \ue8 costituito dalla disponibilit\ue0 di adeguati spazi di allevamento. Per gli intervistati italiani anche l\u2019assenza di mezzi di contenimento (catene o legature) assume particolare rilevanza. Le galline ovaiole (44%), seguite, nell\u2019ordine, dai polli da carne (42%) e dai suini (28%), rappresentano le categorie zootecniche giudicate dai consumatori europei particolarmente bisognose di un miglioramento in termini di benessere. In tale contesto, gli intervistati italiani pongono un\u2019 attenzione pi\uf9 limitata al benessere dei suini (17%). Per un 12% dei consumatori europei, tutte le specie di interesse zootecnico meritano un miglioramento in termini di benessere e di protezione. In tutta la Comunit\ue0, con entit\ue0 variabile a seconda del paese, risulta in generale difficile riconoscere i prodotti ottenuti adottando standard di benessere animale pi\uf9 elevati dei requisiti minimi presenti nella normativa. Nella nostra come in altre nazioni, gli elementi riguardanti il benessere animale rientrano in generale in schemi produttivi volti a garantire ed a trasmettere un pi\uf9 ampio ed elevato concetto di qualit\ue0 della derrata. Anche la conoscenza della specifica legislazione posta a protezione degli animali negli allevamenti \ue8 piuttosto limitata. In sintonia con il Programma d\u2019Azione Comunitario per la Protezione ed il Benessere degli Animali 2006-2010, l\u2019elaborazione di un\u2019etichetta europea che indichi il livello del benessere animale, basata su indicatori scientifici standardizzati, pu\uf2 costituire un valido mezzo per promuovere le vendita di prodotti rispettosi del benessere animale e rendere, nel contempo, pi\uf9 consapevole il consumatore. Per quanto attiene alla disponibilit\ue0 del consumatore a pagare un prezzo pi\uf9 elevato per i prodotti ottenuti con un maggior rispetto del benessere animale, l\u2019indagine condotta rispetto alle uova ha evidenziato una propensione che, pur variando da stato a stato, \ue8 risultata nel complesso di segno positivo (57%). L\u2019incremento di prezzo ritenuto generalmente accettabile si colloca, tuttavia, entro un intervallo contenuto (5-10%). In considerazione del fatto che la maggioranza degli intervistati percepisce l\u2019esistenza di un nesso fra salubrit\ue0, sicurezza e qualit\ue0 dei prodotti e livello di benessere animale, si pu\uf2 supporre che il rafforzamento di tale vincolo possa condurre ad un miglioramento del benessere animale come tale.The results of some recent European and Italian surveys on consumer perception of farm animal welfare are shown and discussed. Special attention is paid to consumers\u2019 opinions about animal welfare attributes, differences among species (and across countries) in terms of animal welfare perception, \u201canimal-friendly\u201d labels and willingness of purchasers to pay more for food (eggs) deriving from animals raised under higher welfare conditions. From a general standpoint, consumers\u2019 perception and knowledge of animal welfare varies among European countries and it is mainly affected by their economic and educational level. Among animal welfare attributes, a strong preference is given to the availability of spaces, and, in the case of Italian respondents, also to the absence of movement restrictions (chains or tethers). Laying hens (44%), followed by broilers (42%) and pigs (28%) are the categories/species for which rearing conditions in the EU are judged to need the highest improvement in terms of welfare. Italian consumers appear less concerned about swine welfare (17%) than other Europeans. It is noteworthy that 12% of EU respondents states that all farmed animals need more welfare and/or protection. With respect to labels on food packaging, claims for animal welfare often fall within wider schemes for quality assurance and, with the exception of eggs and organic goods, in many countries the possibility of identifying animal friendly products and the knowledge of the specific legislation on farm animal protection are still limited. According to the Community Action Plan on the Protection and Welfare of Animals 2006-2010, the establishment of an EU label for animal welfare, based on standardised scientific indicators, is an option to be explored which could promote the consumption of products elaborated under high welfare standards thus facilitating the choice of consumers. The readiness of consumers to pay more for a higher animal welfare level has been investigated with respect to hen eggs. On the whole, and with deep differences among countries, results indicate that the majority of consumers (57%) are willing to pay more for eggs sourced from animal-friendly systems; however, the increase in price has, in general, a limited extent (5-10%). The perception of a link between food quality, food safety and animal welfare can favourably affect the welfare level of farmed animals

Pool temperature stratification analysis in CIRCE-ICE facility with RELAP5-3D© model and comparison with experimental tests

In the frame of heavy liquid metal (HLM) technology development, CIRCE pool facility at ENEA/Brasimone Research Center was updated by installing ICE (Integral Circulation Experiments) test section which simulates the thermal behavior of a primary system in a HLM cooled pool reactor. The experimental campaign led to the characterization of mixed convection and thermal stratification in a HLM pool in safety relevant conditions and to the distribution of experimental data for the validation of CFD and system codes. For this purpose, several thermocouples were installed into the pool using 4 vertical supports in different circumferential position for a total of 119 thermocouples [1][2]. The aim of this work is to investigate the capability of the system code RELAP5-3D (c) to simulate mixed convection and thermal stratification phenomena in a HLM pool in steady state conditions by comparing code results with experimental data. The pool has been simulated by a 3D component divided into 1728 volumes, 119 of which are centered in the exact position of the thermocouples. Three dimensional model of the pool is completed with a mono-dimensional nodalization of the primary main flow path. The results obtained by code simulations are compared with a steady state condition carried out in the experimental campaign. Results of axial, radial and azimuthal temperature profile into the pool are in agreement with the available experimental data Furthermore the code is able to well simulate operating conditions into the main flow path of the test section

ldentification of virus diseases of grapevine and production of disease-free plants

Der Nachweis von Rebvirosen und die Erzeugung virusfreien PflanzgutesIn dem vorliegenden Übersichtsbericht werden symptomatologische Probleme, der Virusnachweis mit Hilfe von krautigen Testpflanzen und Indikatorreben, serologische Nachweismethoden sowie die Möglichkeiten elektronenmikroskopischer Verfahren behandelt. Abschließend werden die bislang praktizierten Programme für die Erzeugung virusfreien Vermehrungsmaterials diskutiert

Virus diseases of the grapevine in a Sicilian herbarium of the past century

Dried grapevine specimens, collected in Sicily between 1880 and 1886, and showing different morphological and chromatic modifications, were found in a herbarium established in 1830 by Dr. FRANCESCO MINA PALUMBO, a physician of Castelbuono (Palermo). On the basis of symptoms still visible on the specimens and of the herbarium's original explanatory notes, the diseased material was identified as being affected by fanleaf, yellow mosaic and leafroll.Rebvirosen in einem sizilianischen Herbarium aus dem letzten JahrhundertGetrocknete Exemplare von Reben, die zwischen 1880 und 1886 in Sizilien für ein von Dr. FRANCESCO MINA PALUMBO, einem Arzt aus Castelbuono (Palermo), begründetes Herbarium gesammelt worden waren, zeigten verschiedene morphologische und farbliche Modifikationen. Die noch sichtbaren Symptome an den Herbarexemplaren erlauben zusammen mit den erläuternden Originalnotizen eine Diagnose auf Befall durch Reisigkrankheit, Gelbmosaik und Blattrollkrankheit

Gravity duals of supersymmetric gauge theories on three-manifolds

We study gravity duals to a broad class of N=2 supersymmetric gauge theories defined on a general class of three-manifold geometries. The gravity backgrounds are based on Euclidean self-dual solutions to four-dimensional gauged supergravity. As well as constructing new examples, we prove in general that for solutions defined on the four-ball the gravitational free energy depends only on the supersymmetric Killing vector, finding a simple closed formula when the solution has U(1) x U(1) symmetry. Our result agrees with the large N limit of the free energy of the dual gauge theory, computed using localization. This constitutes an exact check of the gauge/gravity correspondence for a very broad class of gauge theories with a large N limit, defined on a general class of background three-manifold geometries.Comment: 74 pages, 2 figures; v2: minor change