CHASMAPORTHETES MELEI N.SP., AN ENDEMIC HYAENID (CARNIVORA, MAMMALIA) FROM THE MONTE TUTTAVISTA FISSURE FILLINGS (LATE PLIOCENE TO EARLY PLEISTOCENE; SARDINIA, ITALY)

Occurrence of large carnivores in island ecosystems is unusual, especially in the case of top predators. Here, a new endemic hyaenid species, Chasmaporthetes melei, from the late Late Pliocene to earliest Pleistocene fissure fillings of Monte Tuttavista, Orosei, Sardinia, is described. Although smaller, C. melei is morphologically comparable with the Plio-Pleistocene Eurasian hunting-hyena Chasmaporthetes lunensis, a possible ancestor of the Sardinian species. C. melei displays all the characteristic feeding adaptations of Chasmaporthetes, including a derived enamel structure similar to the condition in extant bone-crushing hyaenas. C. melei was an active predator that nonetheless included a relatively large amount of bone in its diet. SHORT NOTE

Anterior Capsulolabral Reconstruction with Semitendinosus Autograft after Latarjet Failure. A Case Report

Introduction: The treatment of chronic shoulder instability, associated with poor tissue quality, remains challenging in the setting of anterior capsular deficiency. There are a few viable alternatives in the end-stage shoulder instability when multiple surgical attempts to correct the pathology have failed. The purpose of the present paper is to demonstrate the efficacy of anterior capsular reconstruction with semitendinosus autograft for the management of capsulolabral deficiency without associated bone loss. Case report: A 39-year-old female admitted in our institution with a history of recurrent atraumatic anterior dislocation of the left shoulder after three unsuccessful surgical attempts: Arthroscopic and open capsulorrhaphy and a Latarjet coracoid transfer. CT scan images showed adequate placement (flush) of the coracoid transfer without any sign of reabsorption. Reconstruction of anterior capsulolabral structure was performed using a Semitendinosus autograft. The middle and inferior glenohumeral ligaments, the more crucial ligaments for anterior-inferior shoulder stability, were effectively recreated. The patient did not suffer any recurrent dislocation or subjective symptoms of instability at the time of the final follow-up, 2 years after surgery, and the ASES score increased from 36 preoperatively to 86. Conclusion: This technique, described for the first time as a salvage procedure after Latarjet failure, could represent a safe and viable treatment option in the context of multiple ineffective surgeries

Performance of the readout system of the ALICE Zero Degree Calorimeters in LHC Run 3

The ALICE Zero Degree Calorimeters (ZDC) provide information about event geometry in heavy-ion collisions through the detection of spectator nucleons and allow to estimate the delivered luminosity. They are also very useful in p–A collisions, allowing an unbiased estimation of collision centrality. The Run 3 operating conditions will involve a tenfold increase in instantaneous luminosity in heavy-ion collisions, with event rates that, taking into account the different processes, could reach 5 MHz in the ZDCs. The challenges posed by this demanding environment lead to a redesign of the readout system and to the transition to a continuous acquisition. The new system is based on 12 bit, 1 Gsps FMC digitizers that will continuously sample the 26 ZDC channels. Triggering, pedestal estimation and luminosity measurements will be performed on FPGA directly connected to the front-end. The new readout system and the performances foreseen in Run 3 are presented

First results from the NA60 experiment at CERN

Since 1986, several heavy ion experiments have studied some signatures of the formation of the quark-gluon plasma and a few exciting results have been found. However, some important questions are still unanswered and require new measurements. The NA60 experiment, with a new detector concept that vastly improves dimuon detection in proton-nucleus and heavy-ion collisions, studies several of those open questions, including the production of open charm. This paper presents the experiment and some first results from data collected in 2002.Comment: Paper presented at the XXXVIII Rencontres de Moriond, QCD and High Energy Hadronic Interactions, Les Arcs, March 22-29, 2003. 4 pages, 6 figure

First results from NA60 on low mass muon pair production in In-In collisions at 158 GeV/nucleon

The NA60 experiment at the CERN SPS studies dimuon production in proton-nucleus and nucleus-nucleus collisions. The combined information from a novel vertex telescope made of radiation-tolerant silicon pixel detectors and from the muon spectrometer previously used in NA50 allows for a precise measurement of the muon vertex and a much improved dimuon mass resolution. We report on first results from the data taken for Indium-Indium collisions at 158 AGeV/nucleon in 2003, concentrating on a subsample of about 370 000 muon pairs in the mass range $<1.2$ GeV/$c^{2}$. The light vector mesons $\omega$ and $\phi$ are completely resolved, with a mass resolution of about 23 MeV/$c^{2}$ at the $\phi$. The transverse momentum spectra of the $\phi$ are measured over the continuous range $0<p_{\rm T}<2.5$ GeV/c; the inverse slope parameter of the spectra is found to increase with centrality, with an average value of $T=252\pm3$ MeV.Comment: 9 pages, 6 figures. Plenary talk, SQM2004 conference, Cape Town, South Africa 15-20 September, 2004. To be published in Journal of Physics G: Nuclear and Particle Physic

The ALICE Zero Degree Calorimeters

In the ALICE experiment at Cern LHC, a set of hadron calorimeters will be used to determine the centrality of the Pb-Pb collision. The spectator protons and neutrons, will be separated from the ion beams, using the separator magnet (D1) of the LHC beam optics and respectively detected by a proton (ZP) and a neutron (ZN) "Zero-degree Calorimeter" (ZDC). The detectors will be placed in front of the separator D2 magnet, 115 meters away from the beam intersection point. The ZDCs are quartz-fiber spaghetti calorimeters that exploit the Cherenkov light produced by the shower particles in silica optical fibers.This technique offers the advantages of high radiation hardness (up to several Grad), fast response and reduced lateral dimension of the detectable shower. In addition, quartz-fiber calorimeters are intrinsically insensitive to radio-activation background, which produces particles below the Cherenkov threshold.The ALICE ZDC should have an energy resolution comparable with the intrinsic energy fluctuations, which range from about 20 0.000000or central events to about 5 0.000000or peripheral ones, according to simulations that use HIJING as event generator. The fiber-to-absorber filling ratio must be chosen as a good compromise between the required energy resolution and the fiber cost.The design of the proposed calorimeter will be discussed, together with the expected performances. Whenever possible, the simulated results will be compared with the experimental ones, obtained with the built prototypes and with the NA50 ZDC, which can be considered as a working prototype for the ALICE neutron calorimeter

Influence of Temperature and Humidity on Bakelite Resistivity

Presentation made at RPC99 and submitted to Elsevier PreprintThe use of phenolic or melaminic bakelite as RPC electrodes is widespread. The electrode resistivity is an important parameter for the RPC performance. As recent studies have pointed out, the bakelite resistivity changes with temperature and is influenced by humidity. In order to gain a quantitative understanding on the influence of temperature and humidity on RPC electrodes, we assembled an apparatus to measure resistivity in well-controlled conditions. A detailed description of the experimental set-up as well as the first resistivity measurements for various laminates in different environmental conditions are presented

Study of the Resistive Plate Chambers for the ALICE Dimuon Arm

Presentation made at RPC99 and submitted to Elsevier PreprintThe trigger system for the ALICE Dimuon Arm will be based on Resistive Plate Chambers. An RPC prototype, with electrodes made of low resistivity bakelite (rho ~ 3.109 &#937;cm) has been tested both at the SPS and at the GIF. The results for operation in streamer mode are presented here

Zero degree Cherenkov calorimeters for the ALICE experiment

International audienceThe collision centrality in the ALICE experiment will be determined by the Zero Degree Calorimeters (ZDCs) that will measure the spectator nucleons energy in heavy ion collisions. The ZDCs detect the Cherenkov light produced by the fast particles in the shower that cross the quartz fibers, acting as the active material embedded in a dense absorber matrix. Test beam results of the calorimeters are presented