Trend Analysis of Air Quality Index in Catania from 2010 to 2014

Abstract Information on air quality in urban areas represents an important objective to raise awareness and participation of citizens towards those measures aimed at containing and reducing vehicular traffic. For several years at the international level, evaluation procedures have been adopted by indices. One of the first synthetic indices, adopted by the United States Environmental Protection Agency (US-EPA), was the Pollution Standard Index (PSI). In 1999, the EPA replaced the PSI index with Air Quality Index (AQI), which includes two new sub-indices, the ozone at ground level and fine particulate. Despite the European Decisions 97/101/EC and 2001/752/EC, have established an exchange of information from networks and individual stations measuring ambient air pollution in Member States, the use of a single index has not yet been defined that allows you to compare different realities. This heterogeneity emerges in Italy as well, where only a few Environmental Protection Agencies disclose indexes to inform citizens. In this article, the Air Quality Index (AQI) currently used by the United States Environmental Protection Agency has been applied to the metropolitan city of Catania, in order to analyze the level of pollution daily from 2010 to 2014. Through the use of the AQI it was possible to synthesize in a single daily value, concentrations of major pollutants in urban areas (NO2, O3, CO, SO2, PM10) for the entire period. For the calculation procedure of the AQI, the data concentrations were provided by Municipal Ecology and Environment Office. The data relates to three monitoring stations, whose locations have not changed over the years. This also made it possible to evaluate the change in frequency of AQI agglomerations where the monitoring units have been positioned. The value obtained by the AQI for each station has been ranked in six levels of pollution; each level has been associated with a particular coloring allowing this information to be more intuitive. Lastly, it was possible to reach the air quality assessment in urban environment from the frequency variations of each level derived from the year 2010 until 2014

Localizzazione probabilistica 3D (NonLinLoc) applicata all’area calabro-peloritana

Sono presentati e discussi i risultati preliminari relativi ad una ri-localizzazione probabilistica non-lineare 3D dei terremoti dell’area compresa tra il Tirreno meridionale e l’Arco Calabro-Peloritano (Italia meridionale). Scopo del lavoro è dimostrare che l’applicazione di un’approccio probabilistico non-lineare nella localizzazione dei terremoti può fornire dei risultati più accurati ai fini della sorveglianza, ovviando al problema degli outlier, rispetto alle tecniche di localizzazione lineari (e.g. Hypoellipse), che minimizzano simultaneamente tutti i residui tra fasi osservate e calcolate. Il programma utilizzato è NonLinLoc [Lomax, et al., 2000; Lomax, et al., 2001; Lomax, 2005; http://www.alomax.net/nlloc; NonLinLoc di seguito] il quale permette di effettuare un’efficiente ricerca globale dello spazio dei parametri ipocentrali (coordinate spaziali e tempo origine) ottenendo una stima della funzione densità di probabilità (pdf, probability density function) a posteriori. La pdf fornisce una descrizione completa della localizzazione e delle sue incertezze; il campionamento dello spazio dei parametri ipocentrali è stato fatto mediante la tecnica Oct-tree nella regione compresa tra 37.75 e 39.40 N in latitudine e tra 14.80 e 16.80 E in longitudine, e utilizzando tutti gli eventi con profondità H ≤30 km. La struttura dell’Oct-tree è stata imposta in 100,000 celle ed un insieme di queste celle viene poi salvata in modo da poter rappresentare graficamente la pdf mediante nubi di punti a diversa densità. Il dataset utilizzato per le nostre analisi è composto da 1,304 terremoti, di 1.0<M<4.3, registrati nel periodo compreso tra il 1994 e il 2006; il modello di velocità 3D adottato è stato ottenuto da Barberi et al., 2008 [poster presentato a questo convegno] invertendo lo stesso dataset, mediante l’utilizzo del software TomoDD. I risultati ottenuti sono stati confrontati sia con le localizzazioni 1D (Hypoellipse) che con quelle 3D. Si evidenzia una maggiore clusterizzazione degli eventi e, soprattutto, un evidente miglioramento della qualità delle localizzazioni utilizzando il modello di velocità crostale 3D. Per cui riteniamo che, l’applicazione del metodo probabilistico associato ad un buon modello di velocità 3D, può essere utilizzato ai fini di sorveglianza

Analysis of sustained long-period activity at Etna Volcano, Italy

Following the installation of a broadband network on Mt. Etna, sustained Long- Period (LP) activity was recorded accompanying a period of total quiescence and the subsequent onset of the 2004–2005 effusive episode. From c. about 56000 events detected by an automatic classification procedure, we analyse a subset of about 3000 signals spanning the December 17th, 2003–September 25th, 2004, time interval. LP spectra are characterised by several, unevenly-spaced narrow peaks spanning the 0.5–10 Hz frequency band. These peaks are common to all the recording sites of the network, and different from those associated with tremor signals. Throughout the analysed time interval, LP spectra and waveforms maintain significant similarity, thus indicating the involvement of a non-destructive source process that we interpret in terms of the resonance of a fluid-filled buried cavity. Polarisation analysis indicates radiation from a non-isotropic source involving large amounts of shear. Concurrently with LP signals, recordings from the summit station also depict Very-Long-Period (VLP) pulses whose rectilinear motion points to a region located beneath the summit craters at depths ranging between 800 and 1100 m beneath the surface. Based on a refined repicking of similar waveforms, we obtain robust locations for a selected subset of the most energetic LP events from probabilistic inversion of travel-times calculated for a 3D heterogenous structure. LP sources cluster in a narrow volume located beneath the summit craters, and extending to a maximum depth of ≈800 m beneath the surface. No causal relationships are observed between LP, VLP and tremor activities and the onset of the 2004–2005 lava effusions, thus indicating that magmatic overpressure played a limited role in triggering this eruption. These data represent the very first observation of LP and VLP activity at Etna during non-eruptive periods, and open the way to the quantitative modelling of the geometry and dynamics of the shallow plumbing system

Controlling high-frequency collective electron dynamics via single-particle complexity

We demonstrate, through experiment and theory, enhanced high-frequency current oscillations due to magnetically-induced conduction resonances in superlattices. Strong increase in the ac power originates from complex single-electron dynamics, characterized by abrupt resonant transitions between unbound and localized trajectories, which trigger and shape propagating charge domains. Our data demonstrate that external fields can tune the collective behavior of quantum particles by imprinting configurable patterns in the single-particle classical phase space.Comment: 5 pages, 4 figure

reach to grasp interjoint coordination for moving objects in children with hemiplegia

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Localizzazione probabilistica 3D (NonLinLoc) applicata all’area calabro-peloritana

Sono presentati e discussi i risultati preliminari relativi ad una ri-localizzazione probabilistica non-lineare 3D dei terremoti dell’area compresa tra il Tirreno meridionale e l’Arco Calabro-Peloritano (Italia meridionale). Scopo del lavoro è dimostrare che l’applicazione di un’approccio probabilistico non-lineare nella localizzazione dei terremoti può fornire dei risultati più accurati ai fini della sorveglianza, ovviando al problema degli outlier, rispetto alle tecniche di localizzazione lineari (e.g. Hypoellipse), che minimizzano simultaneamente tutti i residui tra fasi osservate e calcolate. Il programma utilizzato è NonLinLoc [Lomax, et al., 2000; Lomax, et al., 2001; Lomax, 2005; http://www.alomax.net/nlloc; NonLinLoc di seguito] il quale permette di effettuare un’efficiente ricerca globale dello spazio dei parametri ipocentrali (coordinate spaziali e tempo origine) ottenendo una stima della funzione densità di probabilità (pdf, probability density function) a posteriori. La pdf fornisce una descrizione completa della localizzazione e delle sue incertezze; il campionamento dello spazio dei parametri ipocentrali è stato fatto mediante la tecnica Oct-tree nella regione compresa tra 37.75 e 39.40 N in latitudine e tra 14.80 e 16.80 E in longitudine, e utilizzando tutti gli eventi con profondità H ≤30 km. La struttura dell’Oct-tree è stata imposta in 100,000 celle ed un insieme di queste celle viene poi salvata in modo da poter rappresentare graficamente la pdf mediante nubi di punti a diversa densità. Il dataset utilizzato per le nostre analisi è composto da 1,304 terremoti, di 1.0<M<4.3, registrati nel periodo compreso tra il 1994 e il 2006; il modello di velocità 3D adottato è stato ottenuto da Barberi et al., 2008 [poster presentato a questo convegno] invertendo lo stesso dataset, mediante l’utilizzo del software TomoDD. I risultati ottenuti sono stati confrontati sia con le localizzazioni 1D (Hypoellipse) che con quelle 3D. Si evidenzia una maggiore clusterizzazione degli eventi e, soprattutto, un evidente miglioramento della qualità delle localizzazioni utilizzando il modello di velocità crostale 3D. Per cui riteniamo che, l’applicazione del metodo probabilistico associato ad un buon modello di velocità 3D, può essere utilizzato ai fini di sorveglianza

Gas radon emission related to geodynamic activity on Mt. Etna

We report preliminary observations on possible correlations between anomalies of subsoil radon concentration and geodynamical events on Mt. Etna. In recent years several studies have been carried out on radon as a precursor of geophysical events, most of them performed either on tectonic or volcanic areas. The peculiarity of our investigation lies on the choice of the etnean region, in which tectonic and volcanic features are both present. In order to characterize Mt. Etna features by investigating radon gas in soil, two stations were located along the NE-SW direction on Mt. Etna. Each of the two stations is fitted with a radon detector, a 3D seismic station and a meteorological station. Differences in the radon concentration trend in the data from north and south flanks could be linked to different faulting mechanisms and then to different mechanisms of radon uprising. The increase in soil radon concentration could be related to both seismic and volcanic events

The shallow magma pathway geometry at Mt. Etna volcano

A fundamental goal of volcano seismology is to understand the dynamics of active magmatic systems in order to assess eruptive behavior and the associated hazard. Imaging of magma conduits, quantification of magma transport and investigation of long-period seismic sources, together with their temporal variations, are crucial for the comprehension of eruption-triggering mechanisms. At Mt. Etna volcano, several intense episodes of tremor activity were recorded during 2007, in association with strombolian activity and/or intense fire fountaining episodes occurring from the South East Crater (SEC). The locations of the tremor sources and of the long-period seismic events are used here to constrain both the area and the depth range of magma degassing, highlighting the geometry of the shallow conduits feeding SEC. The imaged conduits consist of two connected resonating dike-like bodies, NNW-SSE and NW-SE oriented, extending from sea level to the surface. In addition, we show how tremor, long-period (LP) and very-long-period (VLP) event locations and signatures reflect pressure fluctuations in the plumbing system associated with the ascent/discharge of gas-rich magma linked to the lava fountains. The evidence here reported, also corroborated by ground deformation variations, can help develop a better prediction and early-warning system for those eruptions (effusive or explosive) that apparently manifest no clear precursors