University of Ioannina

About: University of Ioannina is a education organization based out in Ioannina, Greece. It is known for research contribution in the topics: Population & Large Hadron Collider. The organization has 7654 authors who have published 20594 publications receiving 671560 citations. The organization is also known as: Panepistimio Ioanninon.

Suppression of non-prompt J/ψ, prompt J/ψ, and Y(1S) in PbPb collisions at √s NN = 2.76 TeV

Abstract: Yields of prompt and non-prompt J/psi, as well as Y(1S) mesons, are measured by the CMS experiment via their dimuon decays in PbPb and pp collisions at sqrt(sNN) = 2.76 TeV for quarkonium rapidity |y|<2.4. Differential cross sections and nuclear modification factors are reported as functions of y and transverse momentum pt, as well as collision centrality. For prompt J/psi with relatively high pt (6.5

Search for invisible decays of Higgs bosons in the vector boson fusion and associated ZH production modes

Abstract: A search for invisible decays of Higgs bosons is performed using the vector boson fusion and associated ZH production modes. In the ZH mode, the Z boson is required to decay to a pair of charged leptons or a $b\bar{b}$ quark pair. The searches use the 8 TeV pp collision dataset collected by the CMS detector at the LHC, corresponding to an integrated luminosity of up to 19.7 inverse femtobarns. Certain channels include data from 7 TeV collisions corresponding to an integrated luminosity of 4.9 inverse femtobarns. The searches are sensitive to non-standard-model invisible decays of the recently observed Higgs boson, as well as additional Higgs bosons with similar production modes and large invisible branching fractions. In all channels, the observed data are consistent with the expected standard model backgrounds. Limits are set on the production cross section times invisible branching fraction, as a function of the Higgs boson mass, for the vector boson fusion and ZH production modes. By combining all channels, and assuming standard model Higgs boson cross sections and acceptances, the observed (expected) upper limit on the invisible branching fraction at $m_H$=125 GeV is found to be 0.58 (0.44) at 95% confidence level. We interpret this limit in terms of a Higgs-portal model of dark matter interactions.

A graph-constructive approach to solving systems of geometric constraints

Abstract: A graph-constructive approach to solving systems of geometric constraints capable of effeciently handling well-constrained, overconstrained, and underconstrained configurations is presented. The geometric constraint solver works in two phases: in the analysis phase the constraint graph is analyzed and a sequence of elementary construction steps is derived, and then in the construction phase the sequence of construction steps in actually carried out. The analysis phase of the algorithm is described in detail, its correctness is proved, and an efficient algorith to realized it is presented. The scope of the graph analysis is then extended by utilizing semantic information in the form of anlge derivations, and by extending the repertoire of the construction steps. Finally, the construction phase is briefly discussed.

Geant4-DNA example applications for track structure simulations in liquid water: A report from the Geant4-DNA Project.

Abstract: This Special Report presents a description of Geant4-DNA user applications dedicated to the simulation of track structures (TS) in liquid water and associated physical quantities (e.g., range, stopping power, mean free path…). These example applications are included in the Geant4 Monte Carlo toolkit and are available in open access. Each application is described and comparisons to recent international recommendations are shown (e.g., ICRU, MIRD), when available. The influence of physics models available in Geant4-DNA for the simulation of electron interactions in liquid water is discussed. Thanks to these applications, the authors show that the most recent sets of physics models available in Geant4-DNA (the so-called "option4" and "option 6" sets) enable more accurate simulation of stopping powers, dose point kernels, and W-values in liquid water, than the default set of models ("option 2") initially provided in Geant4-DNA. They also serve as reference applications for Geant4-DNA users interested in TS simulations.

18F-FDG PET for Evaluation of Bone Marrow Infiltration in Staging of Lymphoma: A Meta-Analysis

Abstract: The ability of PET with 18F-FDG to evaluate bone marrow infiltration in patients with lymphoma has been a matter of extensive investigation with controversial results. Therefore, we aimed to evaluate systematically, with a meta-analysis, the diagnostic performance of 18F-FDG PET in this setting. Methods: Relevant studies were identified with MEDLINE and EMBASE searches (last update, August 2004). Data on the diagnostic performance of 18F-FDG PET were combined quantitatively across eligible studies. We estimated weighted summary sensitivities and specificities, summary receiver-operating-characteristic (SROC) curves, and weighted summary likelihood ratios. We also conducted separate analyses according to various subgroups. Bone marrow biopsy (BMB) was used as the reference standard. Results: Thirteen eligible nonoverlapping studies, which enrolled a total of 587 patients, were included in the meta-analysis. The independent random-effects weighted estimates of sensitivity and specificity against BMB were 51% (95% confidence interval [CI], 38%–64%) and 91% (95% CI, 85%–95%), respectively. Results were consistent in the SROC curve: a sensitivity of 51% corresponds to a specificity of 92%, whereas a specificity of 91% corresponds to a sensitivity of 55%. The weighted positive likelihood ratio (LR+) was 5.75 (95% CI, 348–9.48) and the negative likelihood ratio (LR−) was 0.67 (95% CI, 0.55–0.82). Six of 12 patients with positive 18F-FDG PET and negative initial biopsy were found to have bone marrow involvement when biopsy was performed at the sites with positive imaging signals. Subgroup analyses showed better sensitivity in patients with Hodgkin’s disease and in aggressive histologic types of non-Hodgkin’s lymphoma than in patients with less aggressive histologic types and in studies using unilateral BMB compared with those using bilateral biopsy. Conclusion: This meta-analysis showed that 18F-FDG PET has good, but not excellent, concordance with the results of BMB for the detection of bone marrow infiltration in the staging of patients with lymphoma. 18F-FDG PET may complement the results of BMB and its performance may vary according to the type of lymphoma.