Local conformal symmetry in non-Riemannian geometry and the origin of physical scales

We introduce an extension of the Standard Model and General Relativity built upon the principle of local conformal invariance, which represents a generalization of a previous work by Bars, Steinhardt and Turok. This is naturally realized by adopting as a geometric framework a particular class of non-Riemannian geometries, first studied by Weyl. The gravitational sector is enriched by a scalar and a vector field. The latter has a geometric origin and represents the novel feature of our approach. We argue that physical scales could emerge from a theory with no dimensionful parameters, as a result of the spontaneous breakdown of conformal and electroweak symmetries. We study the dynamics of matter fields in this modified gravity theory and show that test particles follow geodesics of the Levi-Civita connection, thus resolving an old criticism raised by Einstein against Weyl's original proposal.Comment: 11 pages; v2: matches published version in EPJC; new title, includes new sections on the coupling of matter fields to the extended gravitational secto

IL SISTEMA DI ANALISI AUTOMATICA DEI SEGNALI SISMICI VLP DELLO STROMBOLI

Nel corso degli anni ‘90 l’uso di reti sismiche broadband in aree vulcaniche attive ha permesso di osservare in numerosi casi, segnali VLP (Very Long Period), ovvero segnali transienti con periodo dominante nella banda 2-50 s. Lo Stromboli, che con la sua persistente attività è un generatore di segnali VLP, è uno dei pochi vulcani su cui opera una rete sismica estesa costituita da stazioni broadband. A partire dal maggio 2003, è attivo presso la sede INGV Osservatorio Vesuviano un sistema automatico, denominato EOLO, per il rilevamento, la localizzazione e l’analisi in tempo reale di questi segnali. Il sistema EOLO riceve in ingresso (via internet) i segnali sismici registrati dalla rete broadband INGV dello Stromboli e fornisce, attraverso un’interfaccia web, sia i dati relativi ai singoli eventi VLP che delle statistiche giornaliere, mensili e annuali. L’interfaccia web interagisce con 3 database diversi: quello delle “forme d’onda”, il “catalogo eventi” e il database “statistiche”. Il database “forme d’onda” è costituito da un insieme di file in formato SAC, creati a partire dai segnali “grezzi” ricevuti in input. Il “catalogo eventi” rappresenta il cuore di tutto il sistema ed è implementato mediante SQL. Per ciascun evento VLP individuato, vengono determinati i parametri ipocentrali e le ampiezze alle varie stazioni e vengono inserite nel database “catalogo eventi”. Con periodicità oraria, viene aggiornato il database “statistiche”, costituito da grafici con gli andamenti orari e giornalieri del numero di eventi, della loro intensità e dell’andamento medio della polarizzazione dei segnali sismici VLP. L’interfaccia web consente di visualizzare, attraverso applet Java e script CGI, la localizzazione di ciascun evento, le forme d’onda, spettri e spettrogrammi, ed altre informazioni ritenute utili. Il sistema di rilevamento/localizzazione, che costruisce il database “catalogo eventi” è basato sull’analisi della coerenza delle forme d’onda VLP registrate alle varie stazione. Un calcolatore parallelo, basato su un cluster di 64 processori, esegue in tempo reale l’analisi della funzione semblance (indicativa della coerenza) su una griglia di dimensioni 8 km x 8 km x 2 km a spaziatura regolare 100 m x 100 m x 50 m, centrata sullo Stromboli. L’accadimento di un evento VLP produce il superamento di un valore di soglia della funzione semblance. La posizione del valore massimo della funzione semblance, durante un evento, è assunta come localizzazione. Nei prossimi mesi al sistema esistente sarà aggiunto un modulo per l’inversione della funzione sorgente dei singoli eventi VLP

Sistemi di trasmissione WiFi per il monitoraggio sismico del Vesuvio

First-year engineering students at the University of Queensland used an interactive webbook to acquire information skills. These helped them search information resources for their projects, which they are required to undertake as part of the subject Introduction to professional engineering. The information skills exercise was an integral part of the project and worth 10% of the overall assessment. The exercises were only available on the Web, allowing the students to enter their answers from home or wherever they had access to the Internet. All answers were marked automatically using a database of all possible answers. Students were able to go back to check their answers. Students were assessed on both their responses to the exercises and also their final bibliography which largely reflected the impact of the webbook. The entire process was evaluated. This paper presents the process and the outcomes of the first-year engineering project involving use of WWW for information skills instruction. The webbooks can be found at http://www.library.uq.edu.au/9e105/

Automatic detection of landslides at Stromboli using neural network analysis of seismic signals

Landslides along the Sciara del Fuoco flank of Stromboli volcano are generally accompanied by c1istinctive seismic signals which can be used for srudying this phenomenon. These signals are characterìzed by a spectral content with higher frequencies and a wider band than the typical explosion quakes and volcanic tremor signals which are continuously recorded at Stromboli. Furthermore their amplirude envelope usually shows a cigar-like shape. These two fearures make the detection of such signals quite easy. The detection of landslides at Stromboli has shown to be an important shortterm precursor of effusive eruptions. Before the Feb. 27th 2007 eruption, the opening of the effusive vents was preceded by few hours oI increased occurrence of landslide signals (Martini et al., 2007). Furthermore since the Sciara del Fuoco has shown significant instabilities during the 2002-2003 eruption, the automatic detection of landslide signals is an important monitoring tool for notifying variations in the stability of this flank. We propose a technique based on a Multi Layer Perceptron (MLP) neural network which has shown excellent performances. The network is composed of two layer of neurons, the hidden and the output. The hidden layer is composed of 4 neurons while the output layer is composed by a single neuron whose output value ranges between Oand 1, with values higher than a given threshold (e.g. 0.5) meaning positive detection. The continuous seismic signals are analysed using moving windows of 24 s, with an overlap of 12 s. For each of these windows the neural output is computed. The waveforms of each time window are parametrized using both their spectrogram and their amplirude envelope. The spectrogram is described using the Linear Preclictive Cocling (L'PC) technique which allows to represent the spectral content using a limited number of coefficients. The whole signal is c1ivided into 8 sub-windows of 5.12 s length, with an overlapping of 2.56 s. For each sub-window we compute 6 LPC coefficients, so each spectrogram is described by only 48 coefficients. The amplirude envelope is defined by computing the c1ifference between the maximum and minimum value over 1 s sub-windows obtaining 24 coefficients. In conclusion we use an input vector composed of 72 elements (48+24). This vector has shown to be an efficient and compact representation of the raw signal (composed of 1200 samples) (Esposito et al. 2006). The dataset used for determining the network parameters is composed of 537 signals, c1ivided in two classes: 267 landslide signals and 270 other signals (explosions and tremor). The classification of these signals has been performed by analysts. The training is carried out using subsets of 5/8 of the total dataset. The testing subsets are composed by the remaining 3/8. The network has shown a performance of about 98.7%. This value is an average over 6 random permutations of the dataset. A preliminary real-rime automatic system has already been implemented. This system performs continuous analysis of the seismic signals, publishing them on internal web pages. It allows a detection of the landslides and a comparison with the past activity on arbitrary rime intervals

Istallazione di una stazione per la rivelazione continua Radon mediante spettrometria alfa nella Solfatara di Pozzuoli

INGV (Istituto Nazionale di Geofisica e Vulcanologia, Sezione di Napoli - Osservatorio Vesuviano)Published1-221.4. TTC - Sorveglianza sismologica delle aree vulcaniche attiveN/A or not JCRrestricte

WiFi data transmission system for monitoring volcanic areas: an example application on Mt. Vesuvius

The Seismic Monitoring Network of Mt.Vesuvius, managed by Istituto Nazionale di Geofisica e Vulcanologia, sezione di Napoli, Osservatorio Vesuviano (INGV-OV), currently consists of 13 analog short period stations (9 single component and 4 triaxial), 2 digital broadband stations and a permanent seismic array (composed of 16 triaxial sensors). Moreover 2 dilatometers are installed in the area, that are integrated in the seismic monitoring system. The distance among the station and between each station and the data acquisition center varies from hundreds of meters to some kilometers. Part of the data is collected in local Data Acquisition Centers (CAD) and then centralized at theMonitoring Center of INGV-OV. In recent years, information technology has become fundamental in seismic networks and geophysical instrumentation, this includes also the data transmission systems. In this context, the new standards for wireless networks has proved to be a useful tool for the transmission of geophysical data. This is the reason why we have chosen to adopt the Wireless Fidelity transmission system, based on available frequencies typical of the IEEE 802.11h standard, which allows high capacity data traffic. We have realized different local area networks based on WiFi technology. They can offer a coverage to high density traffic with extensions varying from a few dozen of meters to kilometers. Each network can be connected through a concentrator device, called access points, and a base station, through a high-capacity system of geographic connectivity, which will be responsible for the liaison to the Monitoring Center of INGV-OV, where seismic data are centralized. There the data are acquired and analyzed by automated systems, that produces parametric information in real time. The architecture of local networks and the backbone for data transmission has been designed to allow a modular development that is well suited for the needs of continuous improvement of the network and the introduction of new systems for geophysical and geochemical volcano monitoring. Currently the infrastructure manages a total of 79 channels with a 24-bit at 100 cps sampling, but the network has a much greater potential. So the future transition of the seismic network from analog to a fully digital equipment will be supported by this data transmission system

Quantum spin coverings and statistics

SL_q(2) at odd roots of unity q^l =1 is studied as a quantum cover of the complex rotation group SO(3,C), in terms of the associated Hopf algebras of (quantum) polynomial functions. We work out the irreducible corepresentations, the decomposition of their tensor products and a coquasitriangular structure, with the associated braiding (or statistics). As an example, the case l=3 is discussed in detail.Comment: 15 page

The Recent Seismicity of Campi Flegrei Caldera (Italy)

Campi Flegrei caldera is located in a very densely populated area. Half of the city of Naples lies within the caldera rims with about 350000 people living on this active volcano. For this reason the surveillance of this volcano requires advanced monitoring techniques in order to forecast even minor eruptions. The area was interested in the period 1982-84 by an unrest crisis with more than 16000 earthquakes and about 2m of ground uplift...INGV;Sezione di Napoli,Osservatorio VesuvianoPublishedTenerife, Canary Islands, Spain1.4. TTC - Sorveglianza sismologica delle aree vulcaniche attiveope

The seismic monitoring network of Mt. Vesuvius

Mt. Vesuvius (southern Italy) is one of the most hazardous volcanoes in the world. Its activity is currently characterized by moderate seismicity, with hypocenters located beneath the crater zone with depth rarely exceeding 5 km and magnitudes generally less than 3. The current configu- ration of the seismic monitoring network of Mt. Vesuvius consists of 18 seismic stations and 7 infrasound microphones. During the period 2006- 2010 a seismic array with 48 channels was also operative. The station distribution provides appropriate coverage of the area around the volcanic edifice. The current development of the network and its geometry, under conditions of low seismic noise, allows locating seismic events with M<1. Remote instruments continuously transmit data to the main acquisition center in Naples. Data transmission is realized using different technological solutions based on UHF, Wi-Fi radio links, and TCP/IP client-server applications. Data are collected in the monitoring center of the Osservatorio Vesuviano (Italian National Institute of Geophysics and Volcanology, Naples section), which is equipped with systems for displaying and analyzing signals, using both real-time automatic and manual procedures. 24-hour surveillance allows to immediately communicate any significant anomaly to the Civil Protection authorities