L’evoluzione tettonica del continente antartico

Because of its location, Antarctica represents an observation point of special interest to global seismology. Also, seismology can greatly contribute to the knowledge of Antarctic neotectonics through the study of continental seismicity and lithospheric structure. The sporadic distribution of seismographic stations south of latitude -45 both restricts our knowledge of the Antarctic continent, and leads to a bias in the interpretation of global geophysical properties of the Earth. Installation of seismographic stations should therefore be a priority for an Antarctic program having access to infrastructure in the area and there are particular activities carried on in the framework of the Italian Antarctic program (Programma Nazionale di Ricerche in Antartide, PNRA). In fact, the previously held notion that Antarctica is essentially aseismic has been disproved by using records from established Global Seismic Network stations and recently deployed temporary stations on the Antarctic continent. However, the seismicity observed in Antarctica is very low in comparison with other continental intraplate regions. In the continental intraplate region of Antarctica, earthquakes occur in three settings. Two are likely to have distributions with a tectonic control (although the level may be suppressed by ice-cover); those in the Transantarctic Mountains and scattered events in the interior. Finally, seismicity in the coastal zone and continental margin is likely to be most strongly controlled by the interaction between glacial isostatic adjustment and lithospheric thickness, with a regional tectonic component in some locations

School climate and academic performance of Italian students: the role of disciplinary behaviour and parental involvement

Educational researchers have increasingly recognised the importance of school climate as a malleable factor for improving academic performance. In this perspective, we exploit the data collected by the Italian Institute for the Evaluation of the Education System (INVALSI) to assess the effect of some school climate related factors on academic performance of tenth-grade Italian students. A Multilevel Bayesian Structural Equation Model (MBSEM) is adopted to highlight the effect of some relevant dimensions of school climate (students’ disciplinary behaviour and parents’ involvement) on academic performance and their role on the relationships between student socioeconomic status and achievement. The main findings show that disciplinary behaviour, on the one hand, directly influences the level of competence of the students, and, on the other hand, it partly mediates the effect of socioeconomic background whereas parents’ involvement does not appear to exert any significant effect on students’ performance

Il Museo Geofisico di Rocca di Papa: tra divulgazione e ricerca scientifica

The Geophysical Museum of Rocca di Papa is located in an historical, three floor building, of the small town Rocca di Papa, twentyfive kilometres from Rome. The edifice was, until 1931, the place of the Geodynamic Observatory, created in 1889 by the famous seismologist Michele Stefano De Rossi. The museum is due to an agreement between the Town Council of Rocca di Papa and the Istituto Nazionale di Geofisica (INGV, one of the most important European Research Institutions operating in geophysics) signed in 2000. After bureaucratic passages and two years of important restoration the museum was open to the public at 26th February 2005. The main aim of the Geophysical Museum is to illustrate how experimental data and information, accumulated by science in the course of time, led to new hypotheses on the internal structure of the Earth. The target of the educational and of the scientific disciplines of the Museum is mainly school students of all ages, but also local residents, and tourists: since its opening, approximately two years ago, the Museum has been visited by more than eight-thousand people. Posters, movie presentations, plastics, games and interactive experiments explain to visitors the main topics of geophysics and the stages of scientific research which led to the modern concept of the Earth internal model. Seismic instruments and games are easily accessible so that the visitor can interact with them: experimental data are recorded in real time and displayed through different monitors placed throughout the rooms. The museum has also a small cinema for three dimensional projections which allow visitors to experience a virtual tour on the Alban Hills, the seismic zone where the museum is located, and also on some other Italian tectonic belts where earthquakes occurred in past. The article introduces the museum and the seismological characteristics of the area, and describes the activities, the exhibits of the Museum and their methodology

LA RETE SISMICA DELLA PIANA DI GUIDONIA (LAZIO): DATI PRELIMINARI

After the seismic period during 2001-2002 that has interested the Plain of Guidonia, situated about fifteen kilometres NE of Rome, which events greatest resentment reached the V-VI MCS, have been installed a local seismic purchased by Comune of Guidonia-Montecelio (Rm). The seismic network (RLG) consists of three digital seismic stations with distances of each other about 2 kilometers, activated to leave from the June 2004 and equipped with three components 1 Hz sismometer. Subsequently, the RLG has enriched of other four digital stations equipped with three components 5 Hz sismometer This network has like main objective the high quality data that agree a better definition of the seismic local activity. These data, that integrate those of the Seismographic Centralized National Network (SCNN), agreed a better ipocentre location. Network geometriy was chosen so as to give back the RLG an independent structure to carry out reliable seismicity locations that characterizes the plain of Guidonia. Unfortunately, industrial and human activity, increases in considerable manner the seismic noise, giving back difficult the record of small events. For this motive the location of the sites was more times changed, and lately, after a seismic crisis in the northern side of the Mountains Cornicolani, that has presented with the same features of that of 2001 of Guidonia, some stations were moved in the neighboring village of Palombara Sabina (Rm)

Recent seismicity of the «Acque Albule» travertine basin

The seismic period which occurred in a portion of Guidonia Montecelio and Tivoli territory, two towns situated about twenty kilometres NE of Rome, affected four areas with a high density of population: Guidonia, Collefiorito, Villalba and Bagni di Tivoli. Even though the events had a very low magnitude (less than 3.0), local phenomena, like rumbles and strong vibrations of the ground, frightened inhabitants also because some months before (January 26, 2001) in a village named Marcellina situated a few kilometres away from Guidonia, a large sinkhole (600 m) had appeared without fore signals. The «Istituto Nazionale di Geofisica e Vulcanologia» (INGV) installed some digital stations that monitored the seismic phenomena. This paper has the aim to process all the information acquired during the period, both from the micro and macro seismic point of view, in order to explain the phenomenology that involved the area. The synergy of the two methodologies lead us to the conclusion that two different seismotectonic structures originated the events, one in an anti-apenninic direction, the other in a N-S direction

Occurrence of mycotoxins in extruded commercial dog food

The aim of this study was to determine the presence and the level of contamination of the most important mycotoxins (deoxynivalenol, fumonisin B1 and B2, aflatoxin B1, B2, G1 and G2, ochratoxin A and zearalenone) in 48 samples of extruded dry dog food found in the Italian market (24 samples from standard economy lines, 24 of premium lines). Analyses were performed using ultra-performance liquid chromatography coupled to tandem mass spectrometry. Although the concentrations of the mycotoxins in all samples proved to respect the European legislation with regards to animal feed, the analyses revealed a substantial presence of deoxynivalenol, fumonisins and ochratoxin A, with values above the limit of quantification (5 \ub5g/kg) in 100%, 88% and 81% of the samples, respectively. In contrast, aflatoxins and zearalenone contamination proved to be very modest, with 88% and 75% of the samples, respectively, showing concentrations below the corresponding limit of quantification (5 \ub5g/kg for aflatoxins and 10 \ub5g/kg for zearalenone). Moreover, despite a very heterogeneous contamination, the concentration of fumonisins and ochratoxin A was significantly higher in standard foods than in premium ones (491 vs. 80.2 \ub5g/kg dry matter for fumonisin B1; 113 vs. 38.5 \ub5g/kg dry matter for fumonisin B2; 599 vs. 103 \ub5g/kg dry matter for total fumonisins; 23.8 vs. 13.0 \ub5g/kg dry matter for ochratoxin A; P < 0.001). Furthermore, a simultaneous presence of different mycotoxins (at concentrations higher than their limit of quantification) was observed in most of the pet foods analyzed; in particular, 19% of the samples were contaminated by no fewer than two different types of mycotoxins, 52% by three, 25% by four and 2% by all the mycotoxins evaluated. These results revealed the need for further investigation into the potential risk deriving from chronic exposure to low doses of the different types of mycotoxins that pet species are subject to today

RECENT SEISMICITY (2000-2007) IN THE TIBURTINI-PRENESTINI MOUNTAINS REGION (LATIUM, ITALY)

A detailed knowledge of the seismicity distribution enables us to gain a better understanding of the recent tectonic evolution and the present-day state of stress of the Tiburtini and Prenestini Mountains region, whose seismic importance is related with the nearness to the town of Rome. It has been carried out an analysis of the seismicity of the region using the data recorded by the permanent stations belonging to the Italian National Seismic Network (RSNC) from 2000, and subsequently integrated with data of local seismic network from 2003 to 2007. The increase of the number of stations in the last years allow us to obtain better quality earthquake localization as before done. We have produced a large database of re-picked events collecting arrival times of P and S waves of local earthquakes with magnitude larger than 2.0, belonging to the 2000-2007 period. The work is subdivided into three step. The first one consists in the determination of the VP/VS ratio using the modified Wadati method. In the second step we perform the analysis of the 1D velocity model that better approximates the structure of the crust in the studied area using the VELEST code (Kissling et al., 1995). Finally, we have the step with earthquake locations and focal mechanisms computation using the first motion polarities method. Fault plane solutions are selected following the two quality factors defined by the FPFIT code (Reasenberg and Oppenheimer, 1985). For the determination of the regional stress field it is used the focal mechanism inversion method elaborated by Gephart and Forsyth (1984). These results are compared with those available from the historical seismicity that struck the region under study

Laryngotracheal stenosis treated with multiple surgeries: experience, results and prognostic factors in 70 patients

Laryngotracheal stenosis is a complex condition that usually requires multiple procedures to restore physiological respiration. The aim of this study was to evaluate the percentage of decannulation compared to different or multiple surgical treatments. We retrospectively reviewed the charts of 70 patients treated between 1990 and 2005 for laryngotracheal stenosis of various aetiology: iatrogenic stenosis (n = 55), post-traumatic stenosis (n = 11) or other causes (autoimmune disease, n = 3; diphtheria, n = 1). In order to maintain laryngotracheal patency, a Montgomery Safe-T tube was used in all patients as a single dilation treatment or associated with endoscopic and/or open-neck surgery. Fifty-four of the 70 patients (77.1%) were eventually decannulated; 39 of these (72.2%) underwent 3 or fewer surgical procedures, showing a significant difference compared to patients who underwent more than 3 surgeries (p = 0.00002). A total of 257 surgeries were performed. Only seven of 54 patients (13%) were decannulated after more than 5 surgical procedures. Patients over 60 years of age and with a higher grade of stenosis showed a significantly lower success rate (p = 0.0017 and p = 0.007, respectively). There was no significant correlation between the rate of decannulation and gender, aetiology, site of stenosis or surgery. Patients undergoing dilation for laryngotracheal stenosis usually require multiple procedures. The T tube plays an important role in the treatment of this pathology. However, if the tracheostomy is not removed within 3 surgical interventions, the odds of decannulating the patient decrease significantly, and additional surgeries may be of questionable therapeutic benefit