4,898 research outputs found

    A study of the pi^0pi^0 system produced in charge exchange and central collisions

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    A study of the π0π0\pi^0\pi^0 system produced in charge exchange π−p\pi^-p collisions at 38 and 100 GeV/c and in central pppp interactions at 450 GeV/c has been carried out. The SS wave has rather a complicated structure in both processes indicating the existence of several scalar resonances. The f0(980)f_0(980) and f0(1500)f_0(1500) appear as dips at 1 and 1.5 GeV in the SS wave for charge exchange reaction, and as shoulders at these masses in the SS wave for central production. The production of the f0(980)f_0(980), f0(1300)f_0(1300) and f0(1500)f_0(1500) in the reaction pp→pfπ0π0pspp \to p_f\pi^0\pi^0p_s as a function of the dPTdP_{T} kinematical filter shows the behaviour differed from what has been observed for the undisputed qqˉq\bar{q} mesons. An extra f0(2000)f_0(2000) state is seen in the SS wave for charge exchange reaction as a dip at 2 GeV. Resonances with higher spins, f2(1270)f_2(1270), f4(2050)f_4(2050) and f6(2510)f_6(2510), have also been studied. All the three mesons are produced in the reaction π−p→π0π0n\pi^-p\to\pi^0\pi^0{n} mainly via an one-pion exchange for small −t-t, whereas a natural-parity exchange domimates for large −t-t. The behaviour of the centrally produced f2(1270)f_2(1270) as a function of the dPTdP_{T} is consistent with what has been observed for other qqˉq\bar{q} states.Comment: 6 pages, 6 figures, use file stwol.sty, presented at International High-Energy Physics Euroconference in Quantum Chromodynamics, 2-8 July 1998, Montpellier, France on behalf of the GAMS and WA102 Collaboration

    Measuring beauty production in Pb-Pb collisions at the LHC via single electrons in ALICE

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    We present the expected ALICE performance for the measurement of the p_t-differential cross section of electrons from beauty decays in central Pb-Pb collisions at the LHC.Comment: 4 pages, 2 figures, proceeding of poster presentation at "Quark Matter 2005

    Strangeness enhancements at central rapidity in 40 A GeV/c Pb-Pb collisions

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    Results are presented on neutral kaon, hyperon and antihyperon production in Pb-Pb and p-Be interactions at 40 GeV/c per nucleon. The enhancement pattern follows the same hierarchy as seen in the higher energy data - the enhancement increases with the strangeness content of the hyperons and with the centrality of collision. The centrality dependence of the Pb-Pb yields and enhancements is steeper at 40 than at 158 A GeV/c. The energy dependence of strangeness enhancements at mid-rapidity is discussed.Comment: 15 pages, 10 figures and 3 tables. Presented at International Conference on Strangeness in Quark Matter (SQM2009), Buzios, Rio de Janeiro, Brazil, 27 Sept - 2 Oct 2009. Submitted to J.Phys.G: Nucl.Part.Phys, one reference adde

    Optimizing HIV therapy. A consensus project on differences between cytidine analogues and regime compactness

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    The identification of the most effective HAART regimens in different clinical settings is still an issue. The aim of the study was to analyze how the compactness of HAART regimens is perceived and if differences between lamivudine (3TC) and emtricitabine (FTC) do exist according to a panel of Italian HIV/AIDS clinicians, using the Delphi method

    Charge Particle Multiplicity and Transverse Energy Measurements in Au-Au collisions in PHENIX at RHIC

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    We present results on charged particle and transverse energy densities measured at mid-rapidity in Au-Au collisions at sqrt(s_{NN})=200 GeV. The mean transverse energy per charged particle is derived. The results are presented as a function of centrality, which is defined by the number of participating nucleons, and compared to results obtained in Au-Au collisions at sqrt{s_{NN})=130 GeV. A comparison with calculations from various theoretical models is performed.Comment: 4 pages, 5 figures. Talk presented at Quark Matter 2002, Nantes, France, July 18-24, 2002. To appear in the proceedings (Nucl. Phys. A

    Recent Results on Strangeness Production at RHIC

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    Due to its large acceptance, the STAR experiment has acquired a wealth of data on strangeness production for a variety of collisions systems and energies, from p+p to Au+Au. By using the yields and spectra, we address the evolution of the bulk system, including strangeness enhancement and the flavour dependence of radial and elliptic flow. Utilising the fact that we can identify strange baryons and mesons, we investigate different hadronization mechanisms in the intermediate and high pT_{T} regions. The ratios of the particle yields, measured to high pT_{T}, are used to further investigate the range and applicability of the previously reported anomalous baryon production. We also study two-particle azimuthal correlations of identified particles in order to investigate any flavour dependence of jet fragmentation in the available pT_{T} range. Data was presented for a number of different collision systems and energies.Comment: Proceedings of SQM'06 Conference, LA, 2006 (submitted to J. Phys. G

    Adherence in HIV-positive patients treated with single-tablet regimens and multi-pill regimens: findings from the COMPACT study

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    The use of Combination AntiRetroviral Therapy (cART) has decreased the morbidity and mortality of patients infected with HIV. However, adherence to cART remains crucial to prevent virological failure and disease progression. The aim of this study was to assess adherence to treatment among patients treated with Single Tablet Regimen (STR) or with multi-pill regimens based on Protease Inhibitors (PI), Non-Nucleoside Reverse-Transcriptase Inhibitors (NNRTI), or raltegravir (RAL). An observational retrospective cohort analysis based on administrative and clinical databases was conducted at the National Institute for Infectious Diseases (Rome, Italy). HIV-positive patients treated with a cART between Jan 1st, 2008–Dec 31st, 2010 were included. Patients were followed-up for one year since the first prescription during the inclusion period or up to death or switch of at least one drug of the regimen. Adherence and selective non-adherence (days without backbone or 3rd drug) were calculated using pharmacy refill compliance [1]. cART regimens were classified based on number of daily pills (STR vs multi-pill regimen) and on type of third drug. Viral Load (VL) and CD4 cell counts at the end of the follow-up were evaluated. A total of 1,604 patients were analyzed, 70.0% male, age 45.0±8.7, 14.3% newly treated. Patients on STR were 159 (9.9%), PI 878 (54.7%), NNRTI 523 (32.6%), RAL 44 (2.7%). Presence of at least one AIDS-defining conditions (according to Centers for Disease Control classification) was 30% in the STR group, 34% PI, 26% NNRTI, 34% RAL (p=n.s.). Adherence was 80.4±14.7% for STR, 71.8±21.8% PI, 77.1±20.3% NNRTI, 74.0±22.4% RAL. Selective non-adherence was 5.5% (18 days) PI, 2.8% (8 days) NNRTI, 12.5% (43 days) RAL (Figure 1). At the end of the follow-up, VL/CD4 values were available among 709 patients (44%); CD4 count >500 cell/mm3 was observed among 61% of patients on STR, 44% PI, 48% NNRTI, 42% RAL and VL < 50 copies/ml was observed among 96% of patients on STR, 78% PI, 88% NNRTI, 87% RAL. Interruptions in cART refill remain a relevant problem across all cART regimens. Patients on STR displayed a higher adherence rate compared to multi-pill regimes (PI, NNRTI, and RAL), primarily due to lack of selective non-adherence. Patients on STR experienced also higher rates of VL < 50 and CD4 > 500. The use of an STR regimen appears an effective therapeutic option to avoid selective non-adherence and, consequently, to prevent virological failure and disease progression

    Self-reported adherence supports patient preference for the single tablet regimen (STR) in the current cART era

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    Objective: To analyze self-reported adherence to antiretroviral regimens containing ritonavir-boosted protease inhibitors, non-nucleoside reverse transcriptase inhibitors (NNRTI), raltegravir, and maraviroc. Methods: Overall, 372 consecutive subjects attending a reference center for HIV treatment in Florence, Italy, were enrolled in the study, from December 2010 to January 2012 (mean age 48 years). A self-report questionnaire was filled in. Patients were defined as “non-adherent” if reporting one of the following criteria:<90% of pills taken in the last month, ≥1 missed dose in the last week, spontaneous treatment interruptions reported, or refill problems in the last 3 months. Gender, age, CD4, HIV-RNA, years of therapy, and type of antiretroviral regimen were analyzed with respect to adherence. Results: At the time of the questionnaire, 89.8% of patients had <50 copies/mL HIV-RNA and 14.2% were on their first combined antiretroviral therapy. 57% of patients were prescribed a regimen containing ritonavir boosted protease inhibitors (boosted PI), 41.7% NNRTI, 17.2% raltegravir, and 4.8% maraviroc; 49.5% of the subjects were on bis-in-die regimens, while 50.5% were on once-daily regimens, with 23.1% of these on the single tablet regimen (STR): tenofovir/emtricitabine/efavirenz. The non-adherence proportion was lower in NNRTI than in boosted-PI treatments (19.4% vs 30.2%), and even lower in STR patients (17.4%). In multivariable logistic regression, patients with the NNRTI regimen (OR: 0.56, 95% CI: 0.34–0.94) and the STR (OR: 0.45, 95% CI: 0.22–0.92) reported lower non-adherence. Efavirenz regimens were also associated with lower non-adherence (OR: 0.42, 95% CI: 0.21–0.83), while atazanavir/ritonavir regimens were associated with higher non-adherence. No other relation to specific antiretroviral drugs was found. A higher CD4 count, lower HIV-RNA, and older age were also found to be associated with lower non-adherence, while a longer time on combined antiretroviral therapy was related to higher non-adherence. Conclusion: In conclusion, older age, higher CD4 cell counts, lower HIV-RNA viral loads, and the use of STR are all related to lower non-adherence. In particular, the use of STR maintains an advantage in improving adherence with respect to other cARTs, even with the availability of new, well-tolerated antiretroviral drugs and drug classes in recent years
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