5,485 research outputs found
Association between obstructive apnea syndrome during sleep and damages to anterior labyrinth: Our experience
The obstructive sleep apnea syndrome is a chronic condition characterized by frequent episodes of collapse of the upper airways during sleep. It can be considered a multisystem disease. Among the districts involved, even the auditory system was seen to be concerned. It was enrolled a population of 20 patients after polysomnographic diagnosis of OSAS (Apnea Hypopnea Index > 10) and a control group of 28 healthy persons (Apnea Hypopnea Index < 5). Each patient has been subjected to Pure Tone Audiometry, Tympanometry, study of Acoustic Reflex, Otoacoustic Emissions and Auditory Brainstem Response. Moreover they were submitted to endoscopy of upper airway with Muller Maneuver and Epworth Sleepiness Scale (ESS). The values of ESS was 13.5 in OSAS group and 5.4 in control group. The tone audiometry is worse in all frequencies analyzed in OSAS patients, but within the normal range for both groups analyzed by 250 to 1000 Hertz. Otoacoustic emissions show a reduced reproducibility and a lower signal/ noise ratio in OSAS group (P <0.01)
Speech Communication
Contains reports on one research project.U. S. Air Force (Electronic Systems Division) under Contract AF 19(604)-6102National Science Foundation (Grant G-16526)National Institutes of Health (Grant MH-04737-03
Black-hole masses of type 1 AGN in the XMM-Newton bright serendipitous survey
We derive masses of the central super-massive black hole (SMBH) and accretion
rates for 154 type1 AGN belonging to a well-defined X-ray-selected sample, the
XMM-Newton Serendipitous Sample (XBS). To this end, we use the most recent
"single-epoch" relations, based on Hbeta and MgII2798A emission lines, to
derive the SMBH masses. We then use the bolometric luminosities, computed on
the basis of an SED-fitting procedure, to calculate the accretion rates, both
absolute and normalized to the Eddington luminosity (Eddington ratio). The
selected AGNs cover a range of masses from 10^7 to 10^10 Msun with a peak
around 8x10^8 Msun and a range of accretion rates from 0.01 to ~50 Msun/year
(assuming an efficiency of 0.1), with a peak at ~1 Msun/year. The values of
Eddington ratio range from 0.001 to ~0.5 and peak at 0.1.Comment: 14 pages, 11 figures. Accepted for publication in Astronomy &
Astrophysic
Determinants associated with obesity and physical activity in the public and private schools of the city of palermo
Introduction: Obesity is a medical condition associated with premature death and it is a risk factor for many chronic diseases. In this context, performing a regular physical activity promotes a healthy lifestyle, with significant health benefits. The aim of the study was to investigate behaviors that increase the risk of obesity and the determinants that encourage physical activity among adolescents. Materials and methods: The HBSC (Health Behavior in School-aged Children) questionnaire was administered to students in Palermo's private and public schools. For the sampling of public schools the protocol of the HBSC Surveillance System was followed; for the private ones it was opportunistic. Results: Private school students are more likely to exercise more than 3 days per week (OR 1.58) and are more likely to exercise more than 2 times a week (OR 2.08). Obese students in private schools in Palermo are more likely to perform physical activity for less than 3 days a week (OR 3.52) and a higher risk of not having breakfast (OR 10.11) and a snack between main meals (OR 3.82) every day. For all the schools examined, it emerged that obese subjects are more likely not to consume fruit (OR 3.13), to stay more than 6 hours a day in front of PCs and video games (OR 3.24) and more than 2 hours a day in front of TV (OR 3.79). Male students are more likely to perform physical activity for more than 3 days per week (OR 1.48) and intense physical activity at least 2 times per week (OR 1.76) Conclusions: It is necessary to intervene early with training on school and family in order to promote correct and responsible food choices and increase the level of physical activity among students. Therefore prevention interventions must be an integral part of coherent strategies based on tests of agreed effectiveness in order to minimize the risk linked to the development of diseases
Classical analysis of phase-locking transients and Rabi-type oscillations in microwave-driven Josephson junctions
We present a classical analysis of the transient response of Josephson
junctions perturbed by microwaves and thermal fluctuations. The results include
a specific low frequency modulation in phase and amplitude behavior of a
junction in its zero-voltage state. This transient modulation frequency is
linked directly to an observed variation in the probability for the system to
switch to its non-zero voltage state. Complementing previous work on linking
classical analysis to the experimental observations of Rabi-oscillations, this
expanded perturbation method also provides closed form analytical results for
attenuation of the modulations and the Rabi-type oscillation frequency. Results
of perturbation analysis are compared directly (and quantitatively) to
numerical simulations of the classical model as well as published experimental
data, suggesting that transients to phase-locking are closely related to the
observed oscillations.Comment: 18 pages total, 8 figures (typos corrected; minor revisions to
figures and equations
In situ alloying of a modified inconel 625 via laser powder bed fusion: Microstructure and mechanical properties
This study investigates the in situ alloying of a Ni-based superalloy processed by means of laser powder bed fusion (LPBF). For this purpose, Inconel 625 powder is mixed with 1 wt.% of Ti6Al4V powder. The modified alloy is characterized by densification levels similar to the base alloy, with relative density superior to 99.8%. The material exhibits Ti-rich segregations along the melt pool contours. Moreover, Ti tends to be entrapped in the interdendritic areas during solidification in the as-built state. After heat treatments, the modified Inconel 625 version presents greater hardness and tensile strengths than the base alloy in the same heat-treated conditions. For the solution annealed state, this is mainly attributed to the elimination of the segregations into the interdendritic structures, thus triggering solute strengthening. Finally, for the aged state, the further increment of mechanical properties can be attributed to a more intense formation of phases than the base alloy, due to elevated precipitation strengthening ability under heat treatments. It is interesting to note how slight chemical composition modification can directly develop new alloys by the LPBF process
Microstructure and Residual Stress Evolution of Laser Powder Bed Fused Inconel 718 under Heat Treatments
The current work aimed to study the influence of various heat treatments on the microstructure, hardness, and residual stresses of Inconel 718 processed by laser powder bed fusion process. The reduction in residual stresses is crucial to avoid the deformation of the component during its removal from the building platform. Among the different heat treatments, 800 °C kept almost unaltered the original microstructure, reducing the residual stresses. Heat treatments at 900, 980, and 1065 °C gradually triggered the melt pool and dendritic structures dissolution, drastically reducing the residual stresses. Heat treatments at 900 and 980 °C involved the formation of δ phases, whereas 1065 °C generated carbides. These heat treatments were also performed on components with narrow internal channels revealing that heat treatments up to 900 °C did not trigger sintering mechanisms allowing to remove the powder from the inner channels
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