Wet chemical nitridation of GaAs (100) by hydrazine solution for surface passivation

A mild wet nitridation procedure using hydrazine-based solutions has been developed for GaAs (100) surface passivation. Both x-ray photoelectron spectroscopy and spectroscopic ellipsometry show that this nitridation procedure results in a very thin, coherent, and homogeneous GaN layer that is very stable in air. Photoluminescence data show a strong enhancement of the intensity as compared to that of an as-cleaned GaAs sample, indicating that this nitrided layer provides both chemical and electronic passivation of GaAs surfaces. The chemical mechanism of nitridation is discusse

Photoluminescence of nc-Si:Er thin films obtained by physical and chemical vapour deposition techniques: The effects os microstructure and chemical composition

Erbium doped nanocrystalline silicon (nc-Si:Er) thin films were produced by reactive magnetron rf sputtering and by Er ion implantation into chemical vapor deposited Si films. The structure and chemical composition of films obtained by the two approaches were studied by micro-Raman scattering, spectroscopic ellipsometry and Rutherford backscattering techniques. Variation of deposition parameters was used to deposit films with different crystalline fraction and crystallite size. Photoluminescence measurements revealed a correlation between film microstructure and the Er3+ photoluminescence efficiency.FCT Project POCTI/CTM/39395/2001INTAS Project #03-51-648

Spectroscopic ellipsometry study of the layer structure and impurity content in Er-doped nanocrystalline silicon thin films

Er doped nc-Si thin films have been investigated by spectroscopic ellipsometry (SE). The optical response of Er ions in a nc-Si/SiO matrix has been determined by SE, and it has been used to detect Er contents as low as 0.2 at%. The complex layered nanostructure of nc-Si:Er:O has been resolved and it has been found that it is strongly influenced by the Er-doping and the oxygen in-depth distribution profile. SE results are discussed in comparison with data obtained by the standard methods of the X-ray diffraction, Rutherford backscattering and Raman spectroscopy

Colorectal cancer-screening program improves both short- and long-term outcomes: a single-center experience in Trieste

Screening programs (SC) have been proven to reduce both incidence and mortality of CRC. We retrospectively analyzed patients who underwent surgical treatment for CRC between 01/2011 and 01/2017. The current screening program in our region collects patients aged from 50 to 69. For this reason, out of a total of 600 patients, we compared 125 patients with CRC founded during the SC to 162 patients who presented with symptoms and were diagnosed between\ua050\u201369\ua0years old (NO-SC). 45% patients in the SC group were diagnosed as AJCC stage I vs 27% patients in the NO-SC group; 14% vs 20% were stage II, 14% vs 26% were stage III, and 3% vs 14% were stage IV (p 0.002). We found a significant difference in surgical approach: 89% SC vs 56% NO-SC patients had laparoscopic surgery (p 0.002). In the NO-SC group, 16% patients underwent resection in an emergency setting. Only 5% patients in the SC group had postoperative complications vs 14% patients in the NO-SC group (p 0.03). We had a 2-year OS of 86%, being 95% in the SC group and 80% in the NO-SC group (p 0.002). Likewise, the whole 2-year DFS was 77%, whereas it was 90% in the SC group and 66% in the NO-SC group (p 0.002). Screening significantly improves early diagnosis and accelerated surgical treatment. We obtained earlier stages at diagnosis, a less invasive surgical approach, and lower rates of complications and emergency surgery, all this leading to an improvement in both OS and DFS

Displacement power spectrum measurement of a macroscopic optomechanical system at thermal equilibrium

The mirror relative motion of a suspended Fabry-Perot cavity is studied in the frequency range 3-10 Hz. The experimental measurements presented in this paper, have been performed at the Low Frequency Facility, a high finesse optical cavity 1 cm long suspended to a mechanical seismic isolation system identical to that one used in the VIRGO experiment. The measured relative displacement power spectrum is compatible with a system at thermal equilibrium within its environmental. In the frequency region above 3 Hz, where seismic noise contamination is negligible, the measurement distribution is stationary and Gaussian, as expected for a system at thermal equilibrium. Through a simple mechanical model it is shown that: applying the fluctuation dissipation theorem the measured power spectrum is reproduced below 90 Hz and noise induced by external sources are below the measurement.Comment: 11 pages, 9 figures, 2 tables, to be submitte

Pinhole free thin film CdS deposited by chemical bath using a substrate reactive plasma treatment

Achieving a pinhole-free CdS layer is necessary to produce high performance thin film CdTe solar cells. Pinholes in the CdS layer can compromise the efficiency of a CdTe solar cell by causing shunts. We have investigated the use of a plasma treatment of a fluorine doped tin oxide coated glass substrate (NSG TEC15) and its effect on pinhole reduction in thin film CdS layers grown by Chemical Bath Deposition. CdS films, < 100 nm thickness, were deposited on both O2/Ar plasma cleaned and conventionally cleaned substrates. We show that the O2 /Ar plasma treatment of the TEC15 substrate reduced the water contact angle from ~55º to less than 12º indicating a substantial increase in the surface energy. The CdS deposited on the plasma treated TEC 15 was pinhole free, very smooth and homogenous in morphology and composition. Scanning electron microscopy images show that the O2/Ar plasma treatment is effective in increasing film density and grain size. Corresponding spectroscopic ellipsometry measurements show an increase in the refractive index from 2.18 to 2.43 at 550 nm wavelength

HoBi-Like Pestivirus and Its Impact on Cattle Productivity

The clinical features and economic impact of the infection caused by an emerging group of pestiviruses, namely HoBi-like pestivirus, in a cattle herd of southern Italy are reported. In 2011, the virus was first associated with respiratory disease, causing an abortion storm after 1&nbsp;year and apparently disappearing for the following 3&nbsp;years after persistently infected calves were slaughtered. However, in 2014, reproductive failures and acute gastroenteritis were observed in the same herd, leading to a marked decrease of productivity. A HoBi-like strain closely related to that responsible for previous outbreaks was detected in several animals. Application of an intensive eradication programme, based on the detection and slaughtering of HoBi-like pestivirus persistently infected animals, resulted in a marked improvement of the productive performances

Testing the performance of a blind burst statistic

In this work we estimate the performance of a method for the detection of burst events in the data produced by interferometric gravitational wave detectors. We compute the receiver operating characteristics in the specific case of a simulated noise having the spectral density expected for Virgo, using test signals taken from a library of possible waveforms emitted during the collapse of the core of Type II Supernovae.Comment: 8 pages, 6 figures, Talk given at the GWDAW2002 worksho

On line power spectra identification and whitening for the noise in interferometric gravitational wave detectors

In this paper we address both to the problem of identifying the noise Power Spectral Density of interferometric detectors by parametric techniques and to the problem of the whitening procedure of the sequence of data. We will concentrate the study on a Power Spectral Density like the one of the Italian-French detector VIRGO and we show that with a reasonable finite number of parameters we succeed in modeling a spectrum like the theoretical one of VIRGO, reproducing all its features. We propose also the use of adaptive techniques to identify and to whiten on line the data of interferometric detectors. We analyze the behavior of the adaptive techniques in the field of stochastic gradient and in the Least Squares ones.Comment: 28 pages, 21 figures, uses iopart.cls accepted for pubblication on Classical and Quantum Gravit

Inertial control of the mirror suspensions of the VIRGO interferometer for gravitational wave detection

In order to achieve full detection sensitivity at low frequencies, the mirrors of interferometric gravitational wave detectors must be isolated from seismic noise. The VIRGO vibration isolator, called 'superattenuator', is fully effective at frequencies above 4 Hz. Nevertheless, the residual motion of the mirror at the mechanical resonant frequencies of the system are too large for the interferometer locking system and must be damped. A multidimensional feedback system, using inertial sensors and digital processing, has been designed for this purpose. An experimental procedure for determining the feedback control of the system has been defined. In this paper a full description of the system is given and experimental results are presented.Comment: 17 pages, 11 figures, accepted for publication on Review of Scientific Instrument