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

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)

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

The Present Development of CsI Rich Detectors for the ALICE Experiment at CERN

The ALICE Collaboration plans to implement a 12m^2 array consisting of 7 proximity focussed C6F^14 liquid radiator RICH modules devoted to the particle identification in the momentum range: 1 GeV/c - 3.5 GeV/c for pions and kaons. A large area CSI-RICH prototype has been designed and built with the aim to validate the detector parameter assumptions made to predict the performance of the High Momentum Particle Identification System (HMPID) of the ALICE Experiment. The main elements of the prototype will be described with emphasis on the engineering solutions adopted. First results from the analysis of multitrack events recorded with this prototype exposed to hadron beams at the CERN SPS will be discussedList of FiguresFigure 1 General view of the ALICE lay-outFigure 2 Schematic layout of the fast CsI-RICHFigure 3 Perspective view of the HMPID layout with the seven RICH modules tilted according to their position with respect to the interaction vertex. The frame that supports the detectors is also shownFigure 4 Top view of the photodetector anode plane with the wire support spacer. One CsI board, out of six forming the pad cathode plane, is also shown.Figure 5 Perspective view of the HMPID honeycomb panel with the three radiator vesselsFigure 6 Cut away view of the HMPID CsI-RICH showing separately each detector component. Kapton buses that carry signals from the pads to the readout electronics are also shownFigure 7 a)number of resolved photoelectrons per event, b)reconstructed Cherenkov angle per photonFigure 8 C6F14 transmission plots before and after the molecular sieve purificationFigure 9 Display plot showing an SPS event. Three tracks are reconstructed by using the tracking chamber telescope, the associated rings are shown in the HMPID prototypeThis publication also appears as INT-98-20

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 &lt; 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 &lt; 0.01). There were more severe complications in group 2 over group 1 cases (8 vs 0%; P &lt; 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

A progress report on the development of the CsI-RICH detector for the ALICE experiment at LHC

The particle identification in ALICE (A Large Ion Collider Experiment) at LHC will be achieved by two complementary systems based on time of flight measurement, at low $p_t$, and on the Ring Imaging Cherenkov (RICH) technique, at $p_t$ ranging from 2 to 5 GeV/$c$, respectively. The High Momentum PID (HMPID) system will cover $\sim$5\% of the phase space, the single arm detector array beeing composed by seven 1.3$\times$1.3 m$^2$ CsI-RICH modules placed at 4.7 m from the interaction point where a density of about 50 particles/m$^2$ is expected.\\ A 1 m$^2$ prototype, 2/3 of HMPID module size, has been successfully tested at the CERN/PS beam where 18 photoelectrons per event have been obtained with 3 GeV/c pions and 10 mm liquid $\mathrm{C}_6\mathrm{F}_{14}$ radiator. Mechanical problems related to the liquid radiator vessel construction have been solved and the prototype, fully equipped, will be tested at the CERN/SPS to investigate the PID capability in high particle density events.\\ In this report, after an introductory discussion on the requirements for PID in ALICE, the HMPID prototype is described and the main results of beam tests on large area CsI photocathodes, operated in RICH detectors, are given

Morphodynamic model to simulate shoreline evolution at any coastal mound

The work presents the results of a field and numerical study aimed to investigate the resistance and resilience, associated to an artificial shoreline perturbation, on a sandy beach. A temporary groin was deployed on a micro-tidal sea-breeze dominated beach to induce a shoreline perturbation. Wave conditions during the field experiment were highly correlated with sea breeze wind events, inducing a persistent alongshore sediment transport. A new one-line numerical model of beach evolution was calibrated and verified with the field surveys, reproducing both the sediment impoundment and subsequent beach recovery after the groin removal. Thus, the numerical model was able to simulate the mechanisms controlling the growth and decay caused by an artificial perturbation