Strangeness enhancement at midrapidity in Pb–Pb collisions at 158 A GeV/ c : A comparison with VENUS and RQMD models

Recently the WA97 Collaboration has measured $\mathrm{K}^0_{\mathrm{S}}$ , $\mathrm\Lambda$ , $\mathrm\Xi$ , $\mathrm\Omega$ and negative particle yields and transverse mass spectra at central rapidity in Pb–Pb and p–Pb collisions at 158 A GeV/c. These results are compared with the predictions of two of the most widely used event generators for heavy-ion collisions: VENUS 4.12 and RQMD 2.3. Both models predict that enhancements increase with the strangeness content of the particle. They fail, however, to reproduce completely the measured values of yields at central rapidity. In particular, for multistrange particles, VENUS fails to reproduce both the p–Pb and the Pb–Pb data, while RQMD works for p–Pb collisions but seems to be unable to reproduce the $\mathrm\Omega$ data in Pb–Pb collisions. Moreover, the predicted behavior for strangeness production as a function of the centrality of the collision appears to be different from the observed behavior

Hard Probes 2010: Experimental Summary

A (personal) experimental summary of the Hard Probes 2010 conference is presented

Granulocytic myeloid-derived suppressor cells increased in early phases of primary HIV infection depending on TRAIL plasma level

Background It has been demonstrated that Myeloid Derived Suppressor Cells (MDSC) are expanded in HIV-1 infected individuals and correlated with disease progression. The phase of HIV infection during which MDSC expansion occurs, and the mechanisms that regulate this expansion remain to be established. In this study we evaluated the frequency of MDSC in patients during primary HIV infection, and factors involved in MDSC control. Methods Patients with primary (PHI) and chronic (CHI) HIV infection were enrolled. PHI staging was performed according to Fiebig classification, and circulating MDSC frequency and function were evaluated by flow cytometry. Cytokine levels were evaluated by Luminex technology. Results We found that granulocytic MDSC (Gr-MDSC) frequency was higher in PHI compared to healthy donors, but lower than CHI. Interestingly, Gr-MDSC expansion was observed in the early phases of HIV infection (Fiebig II/III), but it was not associated to HIV viral load and CD4 T cell count. Interestingly, in PHI Gr-MDSC frequency was inversely correlated with plasmatic level of TRAIL, while a direct correlation was observed in CHI. Further, lower level of GMCSF was observed in PHI compared with CHI. In vitro experiments demonstrated that, differently from CHI, recombinant TRAIL induced apoptosis of Gr-MDSC from PHI, can effect that can be abrogated by GM-CSF. Conclusion We found that Gr-MDSC are expanded early during primary HIV infection and may be regulated by TRAIL and GM-CSF levels. These findings shed light on the fine mechanisms regulating the immune system during HIV infection, and open new perspectives for immune-based strategies

Study of a New Trigger on Multiplicity and Primary Interaction Vertex using the ALICE Silicon Pixel Detector

New trigger inputs for the ALICE Central Trigger Processor (CTP) are proposed. They are based on the use of Fast Multiplicity (FM) output signals generated by the ALICE Silicon Pixel Detector (SPD). These can be used for a multiplicity based centrality trigger and for a fast on-line computation of the primary vertex. A simple algorithm for primary vertex location at the trigger level is proposed. The precision that can be achieved with this method on centrality selection and primary vertex location, is discussed for interactions with different pseudo-rapidity density level. The feasibility of background rejection is also considered

Recent transmission clustering of HIV-1 C and CRF17_BF strains characterized by NNRTI-related mutations among newly diagnosed men in central Italy

Increased evidence of relevant HIV-1 epidemic transmission in European countries is being reported, with an increased circulation of non-B-subtypes. Here, we present two recent HIV-1 non-B transmission clusters characterized by NNRTI-related amino-acidic mutations among newly diagnosed HIV-1 infected men, living in Rome (Central-Italy)

Strangeness, Charm and Beauty in Quark Matter: SQM 2007 Experimental Overview

This paper aims at providing an experimental overview of the Strangeness in Quark Matter 2007 ConferenceComment: Proceedings of Strangeness in Quark Matter 2007, submitted to Journal of Physics