A WZW model based on a non-semi-simple group

We present a conformal field theory which desribes a homogeneous four dimensional Lorentz-signature space-time. The model is an ungauged WZW model based on a central extension of the Poincar\'e algebra. The central charge of this theory is exactly four, just like four dimensional Minkowski space. The model can be interpreted as a four dimensional monochromatic plane wave. As there are three commuting isometries, other interesting geometries are expected to emerge via $O(3,3)$ duality.Comment: 8 pages, phyzzx, IASSNS-HEP-93/61 Texable versio

L’uso della cartografia digitale come base per la realizzazione di un SIT dedicato alle reti sentieristiche in Campania: esempi ed applicazioni.

The development of the hiking paths network in the Campania Region, its marking and maintenance in the field, as well as the relative cartographic restitution on up-to-date maps are nowadays important objectives, since the naturalistic tourism in mountainous environment has recently become more intense, and consequently it is necessary a correct and secure fruition of the hiking paths in the various Campanian mountains groups. Therefore, it is important implementing a Geographical Information System (GIS) dedicated to the Campanian hiking paths network with the aim of process, storing and managing all the parameters and characteristics of the local paths, also during time. In this study some routes of naturalistic and environmental particular value have been selected, which are located in the Lattari Mountains Group, the Vesuvius National Park and the Capri Island. GPS field survey measurements have been carried out along these routes and stored using the national official digital cartography. The field measurements have been taken during yearly scheduled excursions of the Neapolitan section of the Italian Alpine Club. The acquired data have been plotted on the relative maps, stored with the relative attributes tables and visualized through Google Earth interactively.The obtained results represent a feasibility study for a GIS of the hiking paths network of the Campania Region, with evident advantages and possible future developments not only for the trekkers but also for environment protection goals

Vulnerabilità del territorio vesuviano a fenomeni meteorologici attraverso l’analisi quantitativa di fattori geologici ed antropici.

In questo lavoro viene descritta l’applicazione al territorio vesuviano di una metodologia di analisi geomorfologico-quantitativa multiparametrica da DTM (Digital Terrain Model) di dettaglio (5x5m) in ambiente GIS, utilizzando procedure di analisi e tecniche di valutazione della vulnerabilità a fenomeni meteorologici che tengano conto della complessità dell’assetto geologico, geomorfologico, urbanistico ed economico dell’area. Il risultato del lavoro è stato la realizzazione di mappe di vulnerabilità idrogeologica prodotte tenendo conto delle mutue relazioni tra fattori territoriali ed antropici. L’obiettivo di questo studio è stato sviluppare un sistema di analisi utile alla valutazione del rischio idrogeologico ed al suo controllo e prevenzione, considerato che negli ultimi anni si e’ assistito ad incrementi rilevanti e disordinati dell’urbanizzazione nell’area vesuviana, per la maggior parte abusiva e con forti carenze strutturali, che, unitamente ad eventi piovosi particolarmente intensi nonché alle caratteristiche geologico-geomorfologiche del territorio, hanno causato eventi franosi parossistici come quelli dei comuni di Sarno, Episcopia e Bracigliano. L’area di indagine, rappresentata dal complesso vulcanico del Somma–Vesuvio in Campania, è densamente abitata (2500 abitanti per km2) ed oltre ad essere ad alto rischio vulcanico è anche esposta ad alto rischio idrogeologico come dimostrato dalle ripetute esondazioni disastrose fin dall’epoca storica (Accardo et al., 1981; Catenacci et al., 1992). La conoscenza dell’assetto geologico e geomorfologico del complesso Somma-Vesuvio è necessaria per una corretta individuazione dei parametri utili per questo studio. Un esempio è quello della caratterizzazione dei versanti del vulcano, fattore di notevole importanza per la valutazione del rischio idrogeologico, sia per la pendenza che per le loro caratteristiche morfologiche superficiali. Il primo parametro geomorfologico adottato per l’applicazione della metodologia (Tagil and Jenness, 2008) è stato l’indice di posizione topografica (TPI, Topographic Position Index) che ha consentito una classificazione del paesaggio sia in base alla distribuzione areale delle pendenze (slope position) che in classi uniformi di paesaggio (landform classes). La classificazione finale è stata adeguata al particolare paesaggio oggetto di studio, che è di tipo vulcanico. L’analisi della vulnerabilità è stata condotta tenendo conto della permeabilità del suolo e dei dati pluviometrici in quanto possibili fattori predisponenti al dissesto idrogeologico. Il GIS ha rappresentato lo strumento necessario per gestire dati di tipo diverso ed effettuarne l’analisi e la rappresentazione congiunta. Il software utilizzato è stato ArcGis (9.3) e attraverso l’applicazione Spatial Analyst è stato possibile estrarre dati ed informazioni nuove che non sarebbe stato possibile ottenere con l’analisi geomorfologica classica da cartografia su supporto cartaceo. La realizzazione di mappe di vulnerabilità idrogeologica dell’area del Somma-Vesuvio, ottenute stabilendo le relazioni tra i vari fattori incidenti con l’ausilio di metodologie note (Cherubini et al., 2006), ha rappresentato uno dei risultati del lavoro. Le interrelazioni tra i vari fattori (geologico, geomorfologico, idrogeologico, urbanistico) mostrate dalle mappe prodotte costituiscono uno strumento indispensabile per monitorare il rischio territoriale e per poter intervenire laddove venga superata una soglia di rischio ritenuta accettabile

Bulk viscosity in 2SC and CFL quark matter

The bulk viscosities of two color-superconducting phases, the color-flavor locked (CFL) phase and the 2SC phase, are computed and compared to the result for unpaired quark matter. In the case of the CFL phase, processes involving kaons and the superfluid mode give the largest contribution to the bulk viscosity since all fermionic modes are gapped. In the case of the 2SC phase, ungapped fermionic modes are present and the process u+d u+s provides the dominant contribution. In both cases, the bulk viscosity can become larger than that of the unpaired phase for sufficiently large temperatures (T >~ 1 MeV for CFL, T >~ 0.1 MeV for 2SC). Bulk viscosity (as well as shear viscosity) is important for the damping of r-modes in compact stars and thus can potentially be used as an indirect signal for the presence or absence of color-superconducting quark matter.Comment: 8 pages, 3 figures, contribution to the proceedings of QCD@Work 2007, Martina Franca (Italy

Progress in the development of a S RETGEM-based detector for an early forest fire warning system

In this paper we present a prototype of a Strip Resistive Thick GEM photosensitive gaseous detector filled with Ne and ethylferrocene vapours at a total pressure of 1 atm for an early forest fire detection system. Tests show that it is one hundred times more sensitive than the best commercial ultraviolet flame detectors and therefore, it is able to reliably detect a flame of 1.5x1.5x1.5 m3 at a distance of about 1km. An additional and unique feature of this detector is its imaging capability, which in combination with other techniques, may significantly reduce false fire alarms when operating in an automatic mode. Preliminary results conducted with air filled photosensitive gaseous detectors are also presented. The approach main advantages include both the simplicity of manufacturing and affordability of construction materials such as plastics and glues specifically reducing detector production cost. The sensitivity of these air filled detectors at certain conditions may be as high as those filled with Ne and EF. Long term test results of such sealed detectors indicate a significant progress in this direction. We believe that our detectors utilized in addition to other flame and smoke sensors will exceptionally increase the sensitivity of forest fire detection systems. Our future efforts will be focused on attempts to commercialize such detectors utilizing our aforementioned findings.Comment: Presented at the International Conference on Micropattern gaseous detectors, Crete, Greece, June 200

APPLICAZIONE DI TECNICHE DI COLLASSAMENTO IPOCENTRALE A DUE SEQUENZE SISMICHE DI BASSA ENERGIA NELL’APPENNINO MERIDIONALE

In this study we analyse two recent low energy (Mdmax = 4.1) seismic sequences (1990-1997) that affected the northern sector (Sannio-Benevento area) of the Southern Apennines chain. We applied the Best Estimate Method to earthquake locations in order to constrain the position and geometry of the seismogenic structures. The most striking features of the obtained fault geometries indicate that earthquakes of the 1990 Benevento sequence align along a NW-SE striking structure, while the earthquakes of the 1997 Sannio sequence outline a NNE-SSW striking structure. The southernmost NW-SE structure dips towards the NE, is characterized by a conjugate fault arrangement and overlies the fault responsible for a larger historical earthquake (Iomax = XI MCS, 1688 earthquake). Available focal mechanisms from earthquakes that occurred on the recognized NW-SE and NE-SW faults are consistent with dip-slip normal solutions. This suggests the occurrence of coexisting NW-SE and NE-SW extension in the Southern Apennines

The current progress of the ALICE Ring Imaging Cherenkov Detector

Recently, the last two modules (out of seven) of the ALICE High Momentum Particle Identification detector (HMPID) were assembled and tested. The full detector, after a pre-commissioning phase, has been installed in the experimental area, inside the ALICE solenoid, at the end of September 2006. In this paper we review the status of the ALICE/HMPID project and we present a summary of the series production of the CsI photo-cathodes. We describe the key features of the production procedure which ensures high quality photo-cathodes as well as the results of the quality assessment performed by means of a specially developed 2D scanner system able to produce a detailed map of the CsI photo-current over the entire photo-cathode surface. Finally we present our recent R&D efforts toward the development of a novel generation of imaging Cherenkov detectors with the aim to identify, in heavy ions collisions, hadrons up to 30 GeV/c.Comment: Presented at the Imaging-2006 Conference, Stockholm, Sweden, June 200

Meeting patient expectations in migraine treatment: what are the key endpoints?

Clinical outcomes of migraine treatment are generally based on two major endpoints: acute pain resolution and effects on quality of life (QOL). Resolution of acute pain can be evaluated in a number of ways, each increasingly challenging to achieve; pain relief, pain freedom at 2 h, sustained pain-freedom, and SPF plus no adverse events (SNAE, the most challenging). QOL questionnaires help assess the burden of migraine and identify optimal treatments. Pain resolution and improved QOL form the basis of the ultimate target-meeting patient expectations, to achieve patient satisfaction. To achieve this, it is crucial to choose appropriate endpoints that reflect realistic treatment goals for individual patients. Moreover, SNAE can help discriminate between triptans, with almotriptan having the highest SNAE score. Kaplan-Meier plots are also relevant when evaluating migraine treatments. The use of symptomatic medication may lead to the paradoxical development of medication-overuse headache. In general practice, patients should use simple tools for pain measurement (e.g. headache diary) and a QOL questionnaire. A composite endpoint of pain resolution and QOL restoration would constitute a step forward in migraine management

R&D results on a CsI-TTGEM based photodetector

The very high momentum particle identification detector proposed for the ALICE upgrade is a focusing RICH using a C4F10 gaseous radiator. For the detection of Cherenkov photons, one of the options currently under investigation is to use a CsI coated Triple-Thick-GEM (CsI-TTGEM) with metallic or resistive electrodes. We will present results from the laboratory studies as well as preliminary results of beam tests of a RICH detector prototype consisting of a CaF2 radiator coupled to a 10x10 cm2 CsI-TTGEM equipped with a pad readout and GASSIPLEX-based front-end electronics. With such a prototype the detection of Cherenkov photons simultaneously with minimum ionizing particles has been achieved for the first time in a stable operation mode