MAC Layer QoS Mechanisms for a Geostationary Satellite Network

An efficient resource management is crucial in supporting multimedia traffic in satellite networks. To this, Dynamic Bandwidth Allocation Capabilities mechanisms can be exploited to deliver the required QoS while optimising the bandwidth utilization. This paper just deals with the design of innovative algorithms for scheduling and sending the resource requests queued on a EuroSkyWay [1,2] satellite terminal to a Traffic Resource Manager (TRM). The effectiveness of the defined mechanisms has been evaluated through computer simulations. Particularly, by considering different mixes of MPEG-2 traffic and HTTP traffic, the Average Waiting Time (AWT) of the requests and their Losses Percentage have been calculated and compared with those ones obtained using algorithms proposed in MAC layer EuroSkyWay specifications

Staple line reinforcement with nebulized cyanoacrylate glue in laparoscopic sleeve gastrectomy: A propensity score-matched study

Background: A dreaded complication of laparoscopic sleeve gastrectomy (LSG) is suture leak. The study aimed to assess the efficacy of the nebulized comonomer Glubran 2® (N-butyl-cyanoacrylate + metacrylosysolfolane) applied to the LSG staple line. Methods: A propensity-matched comparison analysis was conducted in 125 patients undergoing LSG between 2017 and 2019. Groups included those treated with Glubran® (group 1, n = 70) and those without Glubran® treatment (group 2, n = 55). Results: There were differences in the mean body mass index (44.4 vs 43 kg/m2; P < 0.05) between the groups. There was a non-significant increase in the operative time for group 1 compared with group 2 (97 ± 8 vs 93.8 ± 10.7 min; P = 0.07), with a greater amount of estimated blood loss (94.5 mL vs 87.8; P < 0.01). There were more severe complications in group 2 over group 1 cases (8 vs 0%; P < 0.05), although postoperative bleeding did not differ between the two groups (1.4 vs 5.4%). There were no postoperative leaks in group 1 patients, but there were two leaks in group 2 cases with an increased length of hospital stay in patients with a leak. Conclusion: Glubran® LSG support may reduce leak risk without increasing operating time

Traumatic experiences in childhood and adolescence: a meta-analysis of prospective studies assessing risk for psychosis

Evidence of the association between traumatic experiences and psychosis are uncertain with respect to temporal order, clinical outcomes and the role of the age and genetic liability. The aim of the present meta-analysis was to explore the temporal relationship between the development of psychosis and traumatic exposure using prospective studies and to examine the role of moderation factors on overall effect sizes. Studies were identified by searching Embase-Ovid, PsycINFO (EBSCO), Pubmed, Scopus, Web of Science databases, and yielded an initial total of 9016 papers, leaving finally 23 after the screening process. Three sets of meta-analyses estimated the risk of developing psychotic experiences or full clinical psychosis by having experienced maltreatment by an adult or bullying by peers or parental death, using the random-effects model. Bullying by peers (OR = 2.28 [1.64, 4.34]), maltreatment by an adult (OR = 2.20 [1.72, 2.81]) and parental death (OR = 1.24 [1.06, 1.44]) all increased the risk of psychosis. Moderator analysis showed that negative effects of bullying were detected especially in those with genetic liability for psychosis and exposure to multiple trauma types; studies with higher prevalence of males showed a stronger risk for those exposed to parental death. No significant meta-regression was found between the risk of developing a full clinical psychosis or a psychotic experience. Lack of studies hampered the results about the age of trauma occurrence. The cumulative effect of being bullied from peers and experiencing other adversities during childhood and/or adolescence, together with genetic liability for psychosis, appears to confer the highest risk for developing psychotic symptoms later in life

Ageing with sacral nerve modulation for fecal incontinence: how many patients get benefit after more than 10 years?

Sacral nerve modulation (SNM) has represented a major advancement in the minimally invasive management of patients with fecal incontinence (FI). Although the success rate in the short-medium term has widely been demonstrated, the very long-term outcomes are poorly investigated. This study aims to assess the effectiveness of SNM in a cohort of patients with a follow-up longer than 10 years. Clinical records of patients submitted to SNM for FI in our tertiary referral colorectal Unit between 1998 and 2010 were retrospectively reviewed looking for status of the implantable pulse generator (IPG), follow-up duration, severity of FI by the St Marks' score and quality of life. 58 patients fulfilled the entry criteria and 36 (58%, median follow-up, 12 years) accepted to take part to the telephone interview, while 22 (38%) were lost to the follow-up. Nineteen patients had their IPG removed (Group A) while 17 (27%) had the SNM still active after a median follow-up of 13 years (Group B). In the group A, the median baseline St Marks' score was 13 and did not change after the IPG removal. In group B, the median baseline St Marks' score was 14, at last IPG substitution, it was of 7 and at the last follow-up dropped to 4. In the group A, the median SF-12 physical and mental scores did not change significantly while they improved significantly in group B. A progressive deterioration of the success rate of SNM with the time has been documented after a very long-term follow-up

A pattern recognition method for the RICH-based HMPID detector in ALICE

A pattern recognition method developed for the High Momentum Particle IDentification (HMPID) detector in the ALICE experiment at CERN is presented. The algorithm is based on the Hough transform with a mapping of the pad coordinate space directly to the Cherenkov angle parameter space. Cherenkov angle reconstruction has been studied as a function of different particle densities in the photodetector using real data taken in the ALICE tests at the CERN SPS: a satisfactory resolution can be achieved even in events where the occupancy reaches more than 12, which is the situation we may be confronted with in central Pb-Pb interactions at LHC. (9 refs)

Lunar Surface exploration based on LCNS orbiters and Onboard Sensor observables

Lunar exploration is a strategic priority to develop and experiment technologies that will pave the way for the future missions to Mars and to other celestial bodies of the Solar System. Robots are expected to prepare the return of humans to the Moon by surveying landing sites, demonstrating in situ resource utilization (ISRU), and expanding our access capabilities to difficult areas, i.e., craters and caves. Succeeding in these challenging tasks requires reliable and efficient navigation and communication capabilities. Therefore, space agencies are encouraging the development of a Lunar Communication and Navigation Service (LCNS) to efficiently support lunar assets. A dedicated LCNS infrastructure would lead to unprecedent advantages in future missions by enabling a constant contact with Earth, even in case of Direct To Earth (DTE) link unavailability, e.g., on the far side of the Moon. To fulfil critical tasks, such as obstacle avoidance, instrument manoeuvring and reaching a precise location on the map, rover near real time positioning is a key requirement. Thus, in our work we investigate a method based on the Extended Kalman Filter (EKF) that implements a multi modal sensor fusion approach to estimate the rover's position and velocity by using observables collected by onboard sensors or provided by a LCNS constellation. We focus on a realistic mission scenario in the Moon's south polar region that includes a robotic vehicle hosting onboard sensors to estimate the travelled distances (Wheel Odometry, WO) and the heading variation (Inertial Measurement Unit, IMU). Furthermore, the LCNS orbiters are supposed to broadcast one-way radio signals that the rover user terminal can detect and exploit, providing GNSS-like functionalities. The rover's localization is accomplished through dead-reckoning during LCNS visibility gaps, by using IMU and WO data and accurate Digital Elevation Models (DEMs) of the lunar surface. Whenever pseudorange and pseudorange rate data are acquired by the rover LCNS terminal, these measurements are processed by the navigation filter in combination with IMU and WO datasets, while optimizing the position, velocity and timing (PVT) computation in terms of integrity, accuracy, and convergence time. The proposed method copes with highly varying LCNS visibility conditions and would significantly improve rover's navigation on the Moon's surface in regions where DTE is not achievable. Moreover, our results confirm that the LCNS would be a valuable source of information to be exploited in combination with onboard sensors to improve the accuracy of the reconstructed rover's traverse

numerical modelling of breaker depth index

The breaker depth index, γb, is commonly used to determine the wave height to water depth ratio where the wave will break (Horikawa, 1988). In the present study, γb has been calculated using a fully nonlinear Boussinesq Type Equations (BTE) wave model with implemented BCI (Breaking Celerity Index). The BCI is a phase-resolving type breaking criterion for calculating the incipient wave breaking conditions (D’Alessandro and Tomasicchio, 2008). The model suitability in predicting γb has been verified against physical data from an experimental investigation conducted with incident regular waves propagating along uniform 1:20 and 1:50 slope beaches (G.V. dos Reis, 1992), and estimates of γb from five existing empirical formulae (Battjes, 1974; Ostendorf and Madsen, 1979; Singamsetti and Wind, 1980; Smith and Kraus, 1990; Goda, 2010). The comparisons showed that BCI presents a better agreement with the physical data with respect to the other investigated formulae in determining the value of γb, independently from the breaker type. In addition, the verification of the BCI in determining γb has been extended to the observed data from a large-scale laboratory experiment on wave hydrodynamics performed over a fixed-bed barred beach (Tomasicchio and Sancho, 2002)

Performance of large area CsI-RICH prototypes for ALICE at LHC

We present the performances of large area CsI-RICH prototypes obtained in single particle events. The differential quantum efficiency of the photocathodes has been deduced from Cherenkov rings by means of two different procedures: a direct measurement with a thin NaF radiator and a Monte Carlo based estimation for a C$_6$F$_{14}$ radiator. A factor of merit of 45 cm$^{-1}$ has been found for the typical detector configuration. Two angle reconstruction algorithms have been used and the different errors affecting the Cherenkov angle resolution have been estimated combining the analytical treatment and the Monte Carlo simulation. Also the dependence on radiator thickness, Cherenkov ring radius, chamber voltage and particle incidence angle has been studied

Final tests of the CsI-based ring imaging detector for the ALICE experiment

We report on the final tests performed on a CsI-based RICH detector equipped with 2 C$_6$F$_{14}$ radiator trays and 4 photocathodes, each of 64$\times$38 cm$^2$ area. The overall performance of the detector is described, using different gas mixtures, in view of optimizing the photoelectron yield and the pad occupancy. Test results under magnetic field up to 0.9 T, photocathode homogeneity and stability are presented

A large area CsI RICH Detector in ALICE at LHC

A 1m2 CsI RICH prototype has been successfully tested in a hadron beam at CERN SPS. The prototype, fully equipped with 15k electronic channels, has been used to identify particles coming from pi-Be interactions. Track reconstruction has been performed by using a telescope consisting of four gas pad chambers. A detailed description of the detector will be presented and results from the test will be discussed.List of figuresFigure 1 Expected proton and antiproton yields including jet quenching mechanism in central Pb-Pb collisions at LHC.Figure 2 Schematic view of the HMPID CsI-RICHFigure 3 Experimental layout used at the SPS/H4 test beamFigure 4 Distributions of the mean number, per ring, of pad hits (Npad), electrons (Ntot) and Cherenkov photoelectrons (Nres) as a function of the single-electron mean pulse heightFigure 5 Mean single-electron pulse height as a function of high voltage measured at the centre of each of the four photocathodesFigure 6 Evaluation of the uniformity of the chamber gain for the photocathode PC32Figure 7 Azimuthal distribution of the photon pad hits in the Cherenkov fiducial zone (HV=2050 V)Figure 8 Photon angle (a) and track Cherenkov angle (b) distributions for beam events at the SPSFigure 9 Track density on the HMPID cathode plane in real 350 GeV/c pi--Be eventsFigure 10 Three dimensional display of an SPS 350 GeV/c pi--Be event. Eleven tracks are reconstructed in the telescope by requiring one hit on each pad chamber to reconstruct a track</UL