In the framework of the Sardinia Radio Telescope (SRT) Early Science Program, we obtained single-dish high-resolution imaging of the Supernova Remnants IC443 and W44 at 7 GHz. By coupling them with SRT 1.5 GHz maps, we provided spatially-resolved spectral measurements that are highlighting a spread in spectral slope distribution. The observed features range from flat or slightly inverted spectra corresponding to bright radio limbs and filaments, to relatively steep spectra in fainter radio regions. Different theoretical possibilities explaining the above challenging findings are discussed. In particular, we exclude that the observed region-dependent wide spread in spectral slope distribution could be related to absorption processes. Our high-frequency results can be directly related to distinct electron populations in the SNRs including secondary hadronic electrons and resulting from different shocks conditions and/or undergoing different cooling processes. Integrated fluxes associated with the whole SNRs obtained by SRT in comparison with previous results in the literature support the evidence for a slight spectral steepening above 1 GHz for both sources, which could be related to primary electrons or more likely secondary hadronic electrons cut-offs.

We present single-dish imaging of the well-known Supernova Remnants (SNRs) IC443 and W44 at 1.5 GHz and 7 GHz with the recently commissioned 64-m diameter Sardinia Radio Telescope (SRT). Our images were obtained through on-the-fly mapping techniques, providing antenna beam oversampling, automatic baseline subtraction and radio-frequency interference removal. It results in high-quality maps of the SNRs at 7 GHz, which are usually lacking and not easily achievable through interferometry at this frequency due to the very large SNR structures. SRT continuum maps of our targets are consistent with VLA maps carried out at lower frequencies (at 324 MHz and 1.4 GHz), providing a view of the complex filamentary morphology. New estimates of the total flux density are given within 3% and 5% error at 1.5 GHz and 7 GHz respectively, in addition to flux measurements in different regions of the SNRs.

In the framework of the Astronomical Validation and Early Science activities of the Sardinia Radio Telescope (SRT, www.srt.inaf.it), we performed 22 GHz imaging observations of SNR W44 and IC443. Thanks to the single-dish imaging performances of SRT and innovative ad hoc imaging techniques, we obtained maps that provide a detailed view of the structure of the remnants. We are planning to exploit the high-frequency radio data of SNRs to better characterize the spatially-resolved spectra and search for possible spectral steepening or breaks in selected SNR regions, assessing the high-energy tail of the region-dependent electron distribution.

In this study, the investigation of crystallization behaviour of Hf-rich aluminate is presented. Different alloys were deposited by ALCVD™ with composition ranging between 16 and 47 Al2O3 mol%. Post-deposition annealings were carried out in single or sequential mode using purified N2 at atmospheric pressure. Process temperature and time were varied from 700°C to 900°C and from 1' to 30' respectively. Upon these conditions, film thermal evolution was observed without any relevant increasing of in interface layer and any change in material composition. Measurements on 20 Al2O3 mol% films evidenced that thermal treatments up to 800°C promoted initial shrinking in thickness and material densification. Above 900°C, all considered aluminates were found to crystallize in orthorhombic phase maintaining original alloy composition. The higher the alumina content, the lower the grain size, the higher the crystallites density. Stability of orthorhombic crystalline structure was demonstrated upon single prolonged annealing up to 30' and upon sequential processes. In correspondence with film crystallization, enhancement of dielectric constant was detected with an increasing trend upon hafnia content. For 20 Al2O3 mol% aluminate, change in k form 19 to 40-45 was observed together with limited degradation in conduction and breakdown characteristics.

Fifty-eight patients underwent vestibular neurotomy via the posterior fossa approach between September 1992 and December 1998 at the ENT department of Legnano. All patients presented a history of disabling unilateral Menière’s disease and underwent complete neuro-otologic evaluation following the 1985 American Academy of Otolaryngology - Head and Neck Surgery (AAO-HNS) guidelines. All patients underwent MRI imaging, ABR and electronystagmographic testing before surgery. Objective analysis of results is reported using the criteria published by the Committee on Hearing and Equilibrium of the AAO-HNS in 1985. According to the AAO formula, 52 patients obtained a score of 0, indicating complete control of major vertigo spells, while four were classified within the ’substantial control’ group. Immediate hearing results indicated that 93 per cent of the patients maintained a level within 10 dB from the preoperative level. Only one patient experienced a subtotal hearing loss yet retained measurable hearing. No major complications were reported. We conclude that a retrosigmoid approach to vestibular neurotomy can be considered a safe and effective procedure in relieving medically refractory vertigo in Menière’s disease while preserving the hearing. Tinnitus and long-term hearing deterioration are not influenced by the procedure.