Coherent spin-networks

In this paper we discuss a proposal of coherent states for Loop Quantum Gravity. These states are labeled by a point in the phase space of General Relativity as captured by a spin-network graph. They are defined as the gauge invariant projection of a product over links of Hall's heat-kernels for the cotangent bundle of SU(2). The labels of the state are written in terms of two unit-vectors, a spin and an angle for each link of the graph. The heat-kernel time is chosen to be a function of the spin. These labels are the ones used in the Spin Foam setting and admit a clear geometric interpretation. Moreover, the set of labels per link can be written as an element of SL(2,C). Therefore, these states coincide with Thiemann's coherent states with the area operator as complexifier. We study the properties of semiclassicality of these states and show that, for large spins, they reproduce a superposition over spins of spin-networks with nodes labeled by Livine-Speziale coherent intertwiners. Moreover, the weight associated to spins on links turns out to be given by a Gaussian times a phase as originally proposed by Rovelli.Comment: 15 page

D7.3 Training materials

This Deliverable gives a detailed description of the comprehensive training programme and of the open educational content that the University of Padua has accomplished up to now for the project "Linked Heritage: Coordination of standard and technologies for the enrichment of Europeana" (CIP Best Practice Network). The final version of D7.3 will be released by the end of the project, when all the Learning Objects will be finished

Il ruolo della movimentazione degli animali nella trasmissione di malattie virali.

Con il termine di “movimentazione” si intende lo spostamento degli animali, per “importazione” l’introduzione di animali da Paesi Terzi (controllo PIF) e per “scambi” si identificano i movimenti all’interno della comunità stessa (controllo UVAC). Le certificazioni relative a questi movimenti si avvalgono del sistema TRACES. Organizzazioni come OIE, FAO e WHO si sono sempre adoperate a tutela della salute umana, della salute animale e delle movimentazioni sicure. Con gli anni il rischio di diffusione delle malattie è diminuito, in seguito al miglioramento della salute animale ed al lavoro portato avanti dall’OIE nella definizione di norme internazionali volte a garantire la sicurezza negli scambi di animali. Tuttavia il fenomeno della globalizzazione ha comportato l’aumento dei traffici e conseguentemente il rischio che ne deriva. La movimentazione è una importante modalità per la diffusione di molte malattie infettive oltre a costituire uno stress per gran parte delle specie animali fino a comprometterne la capacità di far fronte ai patogeni. Le arbovirosi in particolare hanno destato interesse e preoccupazione negli ultimi anni in seguito all’incremento delle movimentazioni e dei cambiamenti climatici. Sarebbe dunque auspicabile lavorare per preferire la movimentazione dei prodotti piuttosto che degli animali vivi. “Trade” is animal’s transfer from one place to another. We distinguish “import” when the animals are brought from Third Countries (BIP check) and intra communitarians trade (UVAC check). Certificates concerning those trades are produced by TRACES system. Those three organizations OIE, FAO and WHO have always done their best to protect both human and animal heath and to protect safe trade. As time has passed, the risk of disease spread has decreased thank to improvement of animal heath and thanks to the OIE’s mission, which has defined internationals roles concerning animal trade safety. At the same time globalization has increased traffic and all the dangers connected to it. Trade causes a very important spread of infectious diseases and causes such a big stress for the majority of animal species making them unable to face pathogens. The arbovirus diseases have provoked interest and worries caused by trade increase and climatic changes recently. We would prefer product trade rather then alive animal trade

Discovering Language through Corpora: the Skills Learners Need and the Difficulties they Encounter

Most scholars agree on considering corpora as a valuable source of linguistic information for native and non-native speakers alike. Few researchers, however, have dealt with and systematically analysed the objective difficulties encountered by students while trying to exploit corpus data. The current paper describes a quantitative study of corpus consultation by learners and aims to establish whether different corpus analysis tasks can be considered to have different degrees of intrinsic difficulty. To this end, 26 corpus project work assignments produced by two different groups of students were assessed and tagged according to specific parameters that reflect the skills needed in corpus analysis. The data were analysed applying both parametric (ANOVA) and non parametric tests (Mann-Whitney U-test), which showed that, despite clear individual and teaching/learning environment differences between the two groups of students, the students’ results in most of the tasks were due to different levels of intrinsic difficulty. This led to the creation of a General Difficulty List of Corpus Analysis Tasks

Small Sample Properties of Copula-GARCH Modelling: A Monte Carlo Study

Copula-GARCH models have been recently proposed in the financial literature as a statistical tool to build flexible multivariate distributions. Our extensive simulation studies investigate the small sample properties of these models and examine how misspecification in the marginals may affect the estimation of the dependence function represented by the copula. We show that the use of normal marginals when the true Data Generating Process is leptokurtic or asymmetric, produces negatively biased estimates of the normal copula correlations. A striking result is that these biases reach their highest value when correlations are strongly negative, and viceversa. This result remains unchanged with both positively skewed and negatively skewed data, while no biases are found if the variables are uncorrelated. Besides, the effect of marginals asymmetry on correlations is smaller than that of leptokurtosis. We finally analyse the performance of these models in terms of numerical convergence and positive definiteness of the estimated copula correlation matrix.Copulas, Copula-GARCH models, Maximum Likelihood, Simulation, Small Sample Properties.

A Copula-VAR-X Approach for Industrial Production Modelling and Forecasting

World economies, and especially European ones, have become strongly interconnected in the last decades and a joint modelling is required. We propose here the use of Copulas to build flexible multivariate distributions, since they allow for a rich dependence structure and more flexible marginal distributions that better fit the features of empirical data, such as leptokurtosis. We use our approach to forecast industrial production series in the core EMU countries and we provide evidence that the copula-VAR model outperforms or at worst compares similarly to normal VAR models, keeping the same computational tractability of the latter approach.Forecasting, Industrial Production, Copulas, VAR models.

A GPU Simulation Tool for Training and Optimisation in 2D Digital X-Ray Imaging

Conventional radiology is performed by means of digital detectors, with various types of technology and different performance in terms of efficiency and image quality. Following the arrival of a new digital detector in a radiology department, all the staff involved should adapt the procedure parameters to the properties of the detector, in order to achieve an optimal result in terms of correct diagnostic information and minimum radiation risks for the patient. The aim of this study was to develop and validate a software capable of simulating a digital X-ray imaging system, using graphics processing unit computing. All radiological image components were implemented in this application: an X-ray tube with primary beam, a virtual patient, noise, scatter radiation, a grid and a digital detector. Three different digital detectors (two digital radiography and a computed radiography systems) were implemented. In order to validate the software, we carried out a quantitative comparison of geometrical and anthropomorphic phantom simulated images with those acquired. In terms of average pixel values, the maximum differences were below 15%, while the noise values were in agreement with a maximum difference of 20%. The relative trends of contrast to noise ratio versus beam energy and intensity were well simulated. Total calculation times were below 3 seconds for clinical images with pixel size of actual dimensions less than 0.2 mm. The application proved to be efficient and realistic. Short calculation times and the accuracy of the results obtained make this software a useful tool for training operators and dose optimisation studies

Inorganic mercury sequestration by a poly(ethylene imine) dendrimer in aqueous solution

The interaction of the G-2 poly(ethylene imine) dendrimer L, derived from ammonia as initiating core, with Hg(II) and HgCl42− was studied in aqueous solution by means of potentiometric (pH-metric) measurements. Speciation of these complex systems showed that L is able to form a wide variety of complexes including 1:1, 2:1, 3:1 and 3:2 metal-to-ligand species, of different protonation states, as well as the anion complexes [(H7L)HgCl4]5+ and [(H8L)HgCl4]6+. The stability of the metal complexes is very high, making L an excellent sequestering agent for Hg(II), over a large pH range, and a promising ligand for the preparation of functionalized activated carbons to be employed in the remediation and the prevention of environmental problems

LQG propagator from the new spin foams

We compute metric correlations in loop quantum gravity with the dynamics defined by the new spin foam models. The analysis is done at the lowest order in a vertex expansion and at the leading order in a large spin expansion. The result is compared to the graviton propagator of perturbative quantum gravity.Comment: 28 page

Infusione continua di detomidina durante chirurgia laparoscopica nel cavallo

RIASSUNTO L’anestesia in stazione quadrupedale è una pratica che permette l’esecuzione di diverse manualità mediche e chirurgiche nel cavallo, senza dover sottoporre il soggetto ai maggiori pericoli di un’anestesia generale. Questa tecnica anestesiologica prevede l’impiego di sedativi in associazione con una tecnica analgesica (somministrazione sistemica, anestesia loco-regionale) qualora la manualità da eseguire comporti l’insorgenza di uno stimolo dolorifico. La laparoscopia prevede l’inserimento intraddominale dei trocar e dello strumentario necessario per eseguire la tecnica. Per evitare danni agli organi da parte dello strumentario in addome, il soggetto deve mantenere una posizione adeguata e non deve effettuare movimenti bruschi. Nello studio è stato formulato un protocollo che ha previsto la sedazione del soggetto mediante la somministrazione di detomidina in associazione con buprenorfina per via endovenosa ed anestesia loco-regionale della porzione interessata dalla chirurgia mediante lidocaina. Per il mantenimento è stata attuata l’infusione endovenosa continua di detomidina con lo scopo di ottenere un livello di sedazione costante nel tempo ed adeguato alla manualità. Infatti la somministrazione di un farmaco per via endovenosa continua permette di variare più rapidamente il livello ematico di questo e, conseguentemente, di poterne modulare gli effetti. La detomidina è un farmaco che produce un accumulo nell’organismo, per cui è stato adottato un protocollo che prevede il dimezzamento il dosaggio dell’infusione ogni quindici minuti. L’impiego di questo protocollo anestesiologico ha permesso di effettuare la procedura laparoscopica senza difficoltà da parte del chirurgo. Il piano analgesico ottenuto è risultato efficace ed adeguato per lo svolgimento della manualità chirurgica. A fine intervento tutti i soggetti hanno ripreso la capacità di deambulare in breve tempo, non presentando complicazioni. SUMMARY Standing horse anesthesia is a practice that allows the execution of medical and surgical techniques, without applying to general anesthesia that is a very stressful and more dangerous event for a horse. In this kind of anesthesia, sedatives are employed in association with an analgesic technique (sistemic analgesia or loco-regional anesthesia) when the practice is supposed to be painful. The abdominal introduction of trocars and of laparoscopic tools is necessary in order to perfom a laparoscopic surgery; for this reason the patient is expected to stand motionless and it is important that it does not make roguh movements during the procedure. The wording of the anesthesia protocol for this study implied the use of detomidine for sedation in association with intravenous buprenorphine as analgesic and loco-regional anesthesia with lidocaine of the surgical area. For the maintenance, detomidine by intravenous continuous infusion was employed with the purpose to obtain a constat sedation level and adequate to the procedure. In fact the constant infusion of drugs permits to change blood concentration more rapidly and consequently it is possible to easily modulate the effects of drugs. Detomidine is a sedative that can accumulate in the organism, so the anesthestic protocol foresaw to halve the dosage every fifteen minutes. This anesthetic protocol provided a good sedation and the laparoscopic technique was performed without problems. The obtained analgesic plan resulted efficacious and adequate for the course of the surgery. At the end of the procedure all the subjects were able rapidly to walk and did not present complications