A Joint Inversion of Ground Deformation and Focal Mechanisms Data for Magmatic Source Modelling

The paucity of geodetic data acquired on active volcanoes can make the understanding of modelling magmatic systems quite difficult. In this study, we propose a novel approach, which allows improving the parameter estimation of analytical models of magmatic sources (e.g., shape, depth, dimensions, volume change, etc.) by means of a joint inversion of surface ground deformation data and P-axes of focal plane solutions. The methodology is first verified against a synthetic dataset of surface deformation and strain within the medium, and then applied to real data from an unrest episode occurred before the May 13 2008 eruption at Mt. Etna (Italy). The main results clearly indicate the joint inversion improves the accuracy of the estimated source parameters by about 70 %. The statistical tests indicate that the source depth is the parameter with the highest increment of accuracy. In addition, a sensitivity analysis confirms that displacements data are more useful to constrain the pressure and the horizontal location of the source than its depth, while the P-axes better constrain the depth estimation

Volcanomagnetic Evidence of the Magmatic Intrusion on 13th May 2008

During the onset of 2008 volcanic crisis at Mt Etna, the near-real time magnetic data provided a continuous updating of the volcano activity state on the northern flank. On the morning of 13th May 2008, significant local magnetic field changes marked the resumption of the eruptive activity characterized by the opening of a fracture field on the northern flank, and an eruptive fissure in the Valle del Bove. In agreement with the northward propagation of seismic events, magnetic signals at 5 stations in the summit area revealed a nearly NNW-SSE oriented magmatic intrusion, which started at about 9:00 GMT, propagated northward for about 2 km, and stopped at 14:00 GMT before reaching the North-East Rift. Magnetic variations, with amplitude ranging between 1.8 nT and -6.5 nT, are consistent with those calculated from piezomagnetic models, where stress-induced changes in rock magnetization are produced by the magmatic intrusion

Vectorial magnetometers for noise reduction in volcanomagnetic monitoring at Mt Etna

The volcanomagnetic monitoring is critically dependent on the ability to detect and isolate magnetic variations related to volcanic activity. Accurate detection of volcanomagnetic anomalies attributable to the volcano’s dynamics requires removing from measurements of the earth’s magnetic field, fluctuations of external origin which may be up to hundreds of nanotesla during geomagnetic storms. The commonly used method of taking simple differences of the total intensity with respect to the simultaneous value at a remote reference is partially successful. Variations in the difference fields arise principally from contrasting electromagnetic properties at magnetometer sites. To improve the noise reduction of geomagnetic data from magnetic network of Mt Etna we developed an adaptive filtering. Magnetic vector data are included as input to the filter, to account for the orientation of the disturbance field. The filter is able to estimate and rectify the model parameters continuously by means of new observations, so that predictions match the observed data. The error of state estimation has been decreased and the filtering accuracy improved. Experimental data collected on Mt Etna during 2010 are analyzed to relate the field variation at a given station to the field at other sites filtering out undesired noise and enhancing signal-to-noise ratio

Space-time gravity variations to look deep into the southern flank of Etna volcano

A microgravity 14-year-long data set (October 1994 - September 2007) recorded along a 24-kilometer East-West trending profile of 19 stations was analyzed to detect underground mass redistributions related to the volcanic activity involving the southern flank of Mt Etna volcano (Italy). A multiresolution wavelet analysis was applied to separate the volcano-related signal from the unwanted components due to mainly instrumental, human-made and seasonal effects. The residual space-time image evidenced two complete gravity increase/decrease cycles mainly affecting the central and eastern stations of the profile. The first gravity increase (early-1995 to end-1996) – decrease (end-1996 to late-1998) cycle reached a maximum amplitude of approximately 90 µGal. The second gravity increase (mid-1999 to mid-2000) – decrease (mid-2000 to early-2004) cycle attained an amplitude of about 80 µGal peak-to-peak. After about five years of a persistent negative gravity anomaly, a new semi-cycle started at the end of 2006 and continued during the last survey carried out in September 2007. We modeled the 1994-2007 gravity anomalies using a Quadratic Programming algorithm to infer the position and the evolution of the sources beneath the profile. The computed positive mass variations of about 1.05 x 1011 kg were interpreted as magma accumulation, while negative mass changes of about -1.20 x 1011 kg could reflect either magma migration or opening of new voids by tectonic tensile stresses within a source volume, where tensional earthquakes occurred

UFGM - 2006 Annual Report

INGV, SEZIONE DI CATANIAPublished2.6. TTC - Laboratorio di gravimetria, magnetismo ed elettromagnetismo in aree attiveope

The role of mentorship in protege performance

The role of mentorship on protege performance is a matter of importance to academic, business, and governmental organizations. While the benefits of mentorship for proteges, mentors and their organizations are apparent, the extent to which proteges mimic their mentors' career choices and acquire their mentorship skills is unclear. Here, we investigate one aspect of mentor emulation by studying mentorship fecundity---the number of proteges a mentor trains---with data from the Mathematics Genealogy Project, which tracks the mentorship record of thousands of mathematicians over several centuries. We demonstrate that fecundity among academic mathematicians is correlated with other measures of academic success. We also find that the average fecundity of mentors remains stable over 60 years of recorded mentorship. We further uncover three significant correlations in mentorship fecundity. First, mentors with small mentorship fecundity train proteges that go on to have a 37% larger than expected mentorship fecundity. Second, in the first third of their career, mentors with large fecundity train proteges that go on to have a 29% larger than expected fecundity. Finally, in the last third of their career, mentors with large fecundity train proteges that go on to have a 31% smaller than expected fecundity.Comment: 23 pages double-spaced, 4 figure

Dry eye in systemic sclerosis patients: Novel methods to monitor disease activity

Background: In systemic sclerosis (SSc) patients, dry eye syndrome (DES) is the most frequent ocular feature. The aim of this study was to investigate ocular DES-related SSc patients and to establish any correlation with the severity of the disease. Methods: Retrospectively, data from 60 patients with SSc underwent ophthalmic examination, where non-invasive film tear break-up time (NIF-TBUT), tear film lipid layer thickness (LLT), anesthetic-free Schirmer test I, tear osmolarity measurement (TearLab System), and modified Rodnan skin score (mRSS) data were collected. The visual analog scale (VAS) and Symptom Assessment in Dry Eye (SANDE) methods were utilized. The results were correlated with mRSS and the duration of SSc. Results: Severe DES occurred in 84% of cases, and was more severe in women. The eyelids were involved in 86.6%, secondary to meibomian gland disease (MGD). A direct correlation was found between the tear osmolarity (mean 328.51 ± 23.8 SD) and skin score (mRSS) (r = 0.79; p < 0.01). Significantly reduced NIF-TBUT, LLT, and Schirmer test I values were observed in the case of severe skin involvement. Conclusions: SSc patients show lipid tear dysfunction related to the severity and duration of the disease due to inflammation and the subsequent atrophy of the meibomian glands

Exploring the impact of mentoring functions on job satisfaction and organizational commitment of new staff nurses

<p>Abstract</p> <p>Background</p> <p>Although previous studies proved that the implementation of mentoring program is beneficial for enhancing the nursing skills and attitudes, few researchers devoted to exploring the impact of mentoring functions on job satisfaction and organizational commitment of new nurses. In this research we aimed at examining the effects of mentoring functions on the job satisfaction and organizational commitment of new nurses in Taiwan's hospitals.</p> <p>Methods</p> <p>We employed self-administered questionnaires to collect research data and select new nurses from three regional hospitals as samples in Taiwan. In all, 306 nurse samples were obtained. We adopted a multiple regression analysis to test the impact of the mentoring functions.</p> <p>Results</p> <p>Results revealed that career development and role modeling functions have positive effects on the job satisfaction and organizational commitment of new nurses; however, the psychosocial support function was incapable of providing adequate explanation for these work outcomes.</p> <p>Conclusion</p> <p>It is suggested in this study that nurse managers should improve the career development and role modeling functions of mentoring in order to enhance the job satisfaction and organizational commitment of new nurses.</p