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This paper report on the long-term stress (1000h) carried out on AlGaN/GaN HEMTs processed on composite SopSiC substrate. Almost all tested devices present good device stability and promising performance. The reliability issues identified during the work are clearly related to the high levels of gate leakage current. All these results are very encouraging and confirm that the composite substrates are very promising for low-cost and high performance AlGaN/GaN HEMT for RF power applications. [Copyright &y& Elsevier]

Abstract: We studied the degradation of AlGaN/GaN High Electron Mobility Transistors (HEMT) after 2-MeV alpha irradiation for two different fluences, namely 1013 α/cm2 and 1014 α/cm2. After the exposure and depending on the irradiation fluence, we observed a drop both in drain current and transconductance, and a reduction in the leakage current of the gate diode. We attributed these effects to bulk damage, radiation-induced formation of deep-level trap sites in the channel layer, and doping compensation/removal in the barrier layer. [Copyright &y& Elsevier]

INTRODUCTION: Much clinical evidence has shown that right ventricular (RV) apical pacing is detrimental to left ventricular function. Preservation of the use of the His-Purkinje (H-P) system may be ideal in heart block that is restricted to the AV node, but may be of no benefit when H-P disease exists. AIM: To investigate the feasibility of direct His-bundle pacing (DHBP) using a new system consisting of a steerable catheter and a new 4.1 F screw-in lead. METHOD: Between May and December 2004, 26 patients (19 male, mean age: 77 +/- 5 years) with a standard pacemaker (PM) indication and preserved His-bundle conduction were enrolled and DHBP was attempted. RESULTS: DHBP was achieved in 24 patients (92%); two patients were paced in the His area, but the paced QRS morphology and duration were different from the native QRS. The mean time for lead positioning was 19 +/- 17 minutes, the mean fluoroscopy time was 11 +/- 8 minutes, and the total procedure time (skin-to-skin including positioning of a quadripolar diagnostic catheter for His recording) was 75 +/- 18 minutes. In DHBP pacing, the acute pacing threshold was 2.3 +/- 1.0 V at a pulse duration of 0.5 msec, and the sensed potentials were 2.9 +/- 2.0 mV. At a 3-month follow-up examination, the same QRS duration and morphology recorded on implantation were observed in all patients. The pacing threshold was 2.8 +/- 1.4 V, and sensed potentials were 2.5 +/- 1.8 mV; the sensing configuration was changed from bipolar to unipolar in 6 patients to resolve undersensing issues. No major complications were observed. CONCLUSIONS: This feasibility study shows that DHBP can be accomplished with a new system consisting of a steerable catheter and an active fixation lead in 92% of the patients in whom it was attempted. [ABSTRACT FROM AUTHOR]

An abstract of the article "Cardiac resynchronisation therapy in heart failure: evaluation of clinical outcome and survival in our experience," by E. Baracca and colleagues is presented.

Summary: This paper aims to clarify the dependence existing between spatial rainfall organisation, basin morphology and runoff response. This is obtained by applying a spatial rainfall metric which describes the spatial rainfall organisation in terms of concentration and dispersion statistics as a function of the flow travel time measured along the river network. The metric is based on the observation that runoff routing through branched channel networks imposes an effective averaging of spatial rainfall excess at equal travel time, in spite of the inherent spatial variability. High resolution radar rainfall fields and a distributed hydrologic model are employed to examine how effective are these statistics in describing the degree of spatial rainfall organisation which is important for runoff modelling, and in quantifying the effects of neglecting the spatial rainfall variability on flood modelling. The investigation focuses on three extreme flash flood events occurred on the Carpathian range (Romania) in the period 2005–2007. The size of the study catchments ranges between 36 and 167km2. The analysis reported here shows that neglecting the spatial rainfall variability results in a considerable loss of simulation Nash–Sutcliffe (NS) efficiency in almost 30% of the cases (NS less than 0.8), with NS less than 0.6 in one of the cases. This provides a significant documentation of the influence of the spatial rainfall variability on runoff modelling for catchment size less than 160km2. Moreover, it is shown that these rainfall statistics, used in combination, are able to isolate and describe the features of rainfall spatial organisation which have significant impact on runoff simulation. An alternative rainfall spatial variability index, which is computed irrespective of flow travel time structure, provides a comparatively poor description of the influence of neglecting rainfall spatial variability on flood modelling. Overall, this implies that rainfall organisation measured along the river network by using the travel time coordinate may be a significant property of rainfall spatial variability when considering flood response modelling. [Copyright &y& Elsevier]

Abstract: The electrical characterization, in DC and pulsed regime, and reliability analysis of T-gate high electron mobility transistors built on SiCopSiC and SopSiC composite substrates under high electric fields are here presented. The impact of different gate–drain overhang lengths on the electrical behavior of SiCopSiC devices is also investigated. We will demonstrate that devices can be efficiently realized over the proposed composite substrates, and that performances and robustness are comparable to devices processed on SiC or sapphire. The sensitivity to ESD-like events is also reported, using emission microscope for the failure analysis investigation. [Copyright &y& Elsevier]

Assessing electronic systems' reliability using prediction handbooks (e.g. MIL-HDBK-217) can lead to wrong reliability predictions due to the assumption of a constant failure rate and the inaccuracy of the proposed semi-empirical models. Despite different initiatives since the last version of the most popular handbook MIL-HDBK-217 (1995) no fundamental improvement was realised that makes use of non-constant failure rate statistics – mandatory to model wear-out - and first principles based Physics-of-Failure modelling. Obtaining detailed PoF models requires physical insights and an extended experimental campaign to establish material properties. This is impossible to perform for a specific application. In this paper, we propose a methodology that combines the two approaches to get an improved reliability estimation and allows for a gradual improvement from a prediction handbook based approach to a PoF based reliability assessment. This methodology has been successfully validated on an industrial case. [ABSTRACT FROM AUTHOR]

In the final configuration of the Divertor Tokamak Test (DTT) facility, 32 front-steering launchers of the Electron Cyclotron Resonance Heating (ECRH) system will be distributed in 4 sectors of the machine. Two different antennas are hosted in the equatorial and in the upper port of each ECRH sector, with 6 and 2 single launchers respectively. This setup will deliver up to 35.2 MW installed power to the plasma, making such ECRH system the most powerful ever implemented at the time of its completion. To comply with compactness and performance requirements, a fully in-vessel driving system has been proposed for the steering mirrors. The system relies on UHV-compliant piezoelectric walking drives to provide biaxial steering capability. The main drawback of piezoelectric drives is their low driving force, in an environment where magnetic torques can be very high because of variable magnetic fields, as those induced by the non-axisymmetric in-vessel coils for plasma control, and especially in case of disruption events. Therefore, the materials of the water-cooled steering mirrors must be chosen in such a way as to minimize magnetic torques while guaranteeing adequate heat conduction. Numerical and analytical models of the magnetic torques acting on the steering mirror have been developed. The models have been applied to the steering mirror to quantify magnetic torques due to various sources and dynamic regimes. The currently proposed Copper–Chromium–Zirconium mirror was proven to be critical. Therefore, compliance requirements for the mirror have been computed, and different solutions have been numerically evaluated for magnetic torque mitigation and heat conduction capability, including combination of different materials and implementation of a tungsten-coated dielectric mirror. [ABSTRACT FROM AUTHOR]

The aim of the present study is to assess the incidence of underloverweight and obesity in a sample of children 6-11 years old in Turin province and to monitor the secular trend in weight. Our survey shows that about 2% of children are underweight, 17% overweight and 3% obese. Males show a prevalence of overweight and obesity, while females show also underweight problems. The comparison of current data with those collected in 1979 by Ente Italiano Moda (E.I.M.) [1] shows a significant increase of weight problems in both sexes: this, in childhood, is an emergent social problem that can produce adverse health effects in adulthood. It could be prevented encouraging correct eating behaviors and active lifestyle among children. [ABSTRACT FROM AUTHOR]

An abstract of the article "Anathomical determinants of left ventricle dissincrony," by S. Aggio and colleagues is presented.

An abstract of the study "Cardiac resynchronization therapy in atrial fibrillation: an InSync Italian Registry long-term follow-up," by F. Oliva and colleagues, is presented.