2,598 research outputs found

    Life Cycle Assessment di sistemi per le auto elettriche

    Get PDF
    Lo sviluppo della trazione elettrica stradale, in particolare con l\u2019uso di batterie al litio, \ue8 uno degli approcci pi\uf9 promettenti alle problematiche di carattere ambientale e per la diversificazione delle fonti di energia. Il lavoro descrive una delle attivit\ue0 svolta nell\u2019ambito dell\u2019Accordo di Programma Ministero dello Sviluppo Economico ed ENEA sulla ricerca del sistema elettrico. In particolare l\u2019ENEA e il Dipartimento dell\u2019Energia dell\u2019Universit\ue0 di Palermo hanno condotto uno studio di LCA delle batterie per autotrazione per valutare le prestazioni energetico-ambientali di questi sistemi

    Ants modulate stridulatory signals depending on the behavioural context

    Get PDF
    Insect societies require an effective communication system to coordinate members’ activities. Although eusocial species primarily use chemical communication to convey information to conspecifics, there is increasing evidence suggesting that vibroacoustic communication plays a significant role in the behavioural contexts of colony life. In this study, we sought to determine whether stridulation can convey information in ant societies. We tested three main hypotheses using the Mediterranean ant Crematogaster scutellaris: (i) stridulation informs about the emitter’caste; (ii) workers can modulate stridulation based on specific needs, such as communicating the profitability of a food resource, or (iii) behavioural contexts. We recorded the stridulations of individuals from the three castes, restrained on a substrate, and the signals emitted by foragers workers feeding on honey drops of various sizes. Signals emitted by workers and sexuates were quantitatively and qualitatively distinct as was stridulation emitted by workers on different honey drops. Comparing across the experimental setups, we demonstrated that signals emitted in different contexts (restraining vs feeding) differed in emission patterns as well as certain parameters (dominant frequency, amplitude, duration of chirp). Our findings suggest that vibrational signaling represents a flexible communication channel paralleling the well-known chemical communication system

    Study of dimuon production in Indium-Indium collisions with the NA60 experiment

    Full text link
    The NA60 experiment at the CERN-SPS is devoted to the study of dimuon production in heavy-ion and proton-nucleus collisions. We present preliminary results from the analysis of Indium-Indium collisions at 158 GeV per nucleon. The topics covered are low mass vector meson production, J/psi production and suppression, and the feasibility of the open charm measurement from the dimuon continuum in the mass range below the J/psi peak.Comment: Contribution at XXXXth Rencontres de Moriond, "QCD and High Energy Hadronic Interactions

    Laparoscopic versus open distal gastrectomy for locally advanced gastric cancer in middle–low-volume centers in Western countries. a propensity score matching analysis

    Get PDF
    Background: Gastrectomy with D2 lymphadenectomy is the standard treatment for patients with resectable gastric cancer. Laparoscopic distal gastrectomy (LDG) is routinely performed for early gastric cancer, and its indications are increasing even for locally advanced gastric cancer. The aim of this study is to compare two middle–low-volume centers in Western countries experience on LDG versus open distal gastrectomy (ODG) for locally advanced gastric cancer in terms of surgical and oncological outcomes. Methods: We reviewed the data of 123 consecutive patients that underwent LDG and ODG with D2 lymphadenectomy between 2009 and 2014. Among them, 91 were eligible for inclusion (46 LDG and 45 ODG). After propensity score matching analysis, using a 1:1 case-control match, 34 patients were stratified for each group. Results: The mean operative time was significantly longer in the LDG group (257.2 vs. 197.2, p < 0.001). No differences were observed in terms of intraoperative blood loss, average number of lymph nodes removed, and lymph node metastases. The postoperative morbidity was comparable in the two groups. LDG group had a significant faster bowel canalization and soft oral intake (p < 0.001). The 5-year overall and disease-free survival were higher for patients treated by laparoscopy, but the post-hoc subgroups analysis revealed that the advantage of LDG was significant just in N0 and stage IB-II patients, whereas N+ and stage III patient’s survival curves were perfectly superimposable. Conclusions: LDG for locally advanced gastric cancer seems to be feasible and safe with surgical and long-term oncological outcomes comparable with open surgery, even in medium–low-volume centers

    Evidence for radial flow of thermal dileptons in high-energy nuclear collisions

    Get PDF
    The NA60 experiment at the CERN SPS has studied low-mass dimuon production in 158 AGeV In-In collisions. An excess of pairs above the known meson decays has been reported before. We now present precision results on the associated transverse momentum spectra. The slope parameter Teff extracted from the spectra rises with dimuon mass up to the rho, followed by a sudden decline above. While the initial rise is consistent with the expectations for radial flow of a hadronic decay source, the decline signals a transition to an emission source with much smaller flow. This may well represent the first direct evidence for thermal radiation of partonic origin in nuclear collisions.Comment: Accepted for publication in Physical Review Letter

    Latest results from NA60

    Get PDF
    The NA60 experiment has measured the production of muon pairs and of charged particles in In+In collisions at a beam energy of 158 AGeV. For invariant dimuon masses below the phi the space-time averaged rho spectral function was isolated by a novel procedure. It shows a strong broadening but essentially no shift in mass. The production of J/psi was measured as a function of the collision centrality. As in previous experiments studying Pb+Pb collisions an anomalous supression is observed, setting in at approximately 90 participant nucleons. Using the charged particles the reaction plane was reconstructed. The elliptic flow of charged particles increases with pt showing a saturation for pt > 2GeV/c. For the first time azimuthal distributions for J/psi are shown.Comment: 9 pages, 11 figures, talk given at the conference "Strangeness in Quark Matter 2006 (SQM2006)", March 2006, Los Angeles, USA, accepted for publication in Journal of Physics

    Ď•\phi Meson Production in In-In Collisions and the Ď•\phi Puzzle

    Full text link
    The NA60 experiment measured dimuon production in In-In collisions at 158 AGeV. This paper presents a high statistics measurement of ϕ→μμ\phi\to\mu\mu with the specific objective to provide insight on the ϕ\phi puzzle, i.e. the difference in the inverse TT slopes and absolute yields measured by NA49 and NA50 in the kaon and lepton channel, respectively. Transverse momentum distributions were studied as a function of centrality. The slope parameter TT shows a rapid increase with centrality, followed by a saturation. Variations of TT with the fit range of the order of 15 MeV were observed, possibly as a consequence of radial flow. The ϕ\phi meson yield normalized to the number of participants increases with centrality and is consistently higher than the yield measured by the NA49 experiment at any centrality.Comment: 4 Pages, 2 Figures. Proceedings of the 20th^{th} International Conference on Ultra-Relativistic Nucleus Nucleus Collision

    Low Mass Dimuon Production in Indium-Indium Collisions at the CERN SPS

    Get PDF
    NA60 is a fixed-target experiment at the CERN SPS which measured dimuon production in nucleus-nucleus and proton-nucleus collisions. In this paper we report on a precision measurement of low-mass muon pairs in 158 AGeV indium-indium collisions. A significant excess of pairs is observed above the yield expected from neutral meson decays. The excess can be isolated by subtraction of expected sources, thanks to the excellent mass resolution and large sample size.Comment: 4 pages, 3 figures, Contribution at XLIst Rencontres de Moriond, "QCD and High Energy Hadronic Interactions

    First Measurement of the rho Spectral Function in High-Energy Nuclear Collisions

    Get PDF
    We report on a precision measurement of low-mass muon pairs in 158 AGeV indium-indium collisions at the CERN SPS. A significant excess of pairs is observed above the yield expected from neutral meson decays. The unprecedented sample size of 360 000 dimuons and the good mass resolution of about 2% allow us to isolate the excess by subtraction of the decay sources. The shape of the resulting mass spectrum is consistent with a dominant contribution from pi+pi-->rho-->mu+mu- annihilation. The associated space-time averaged rho spectral function shows a strong broadening, but essentially no shift in mass. This may rule out theoretical models linking hadron masse
    • …
    corecore