775 research outputs found

    Nonperturbative Uncertainties on the Transverse Momentum Distribution of Electroweak Bosons and on the Determination of the W Boson Mass at the LHC

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    In this contribution we present an overview of recent results concerning the impact of a possible flavour dependence of the intrinsic quark transverse momentum on electroweak observables. In particular, we focus on the spectrum of electroweak gauge bosons produced in proton-proton collisions at the LHC and on the direct determination of the boson mass. We show that these effects are comparable in size to other nonperturbative effects commonly included in phenomenological analyses and should thus be included in precise theoretical predictions for present and future hadron colliders

    Effects of TMD evolution and partonic flavor on e+e−e^+e^- annihilation into hadrons

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    We calculate the transverse momentum dependence in the production of two back-to-back hadrons in electron-positron annihilations at the medium/large energy scales of BES-III and BELLE experiments. We use the parameters of the transverse-momentum-dependent (TMD) fragmentation functions that were recently extracted from the semi-inclusive deep-inelastic-scattering multiplicities at low energy from HERMES. TMD evolution is applied according to different approaches and using different parameters for the nonperturbative part of the evolution kernel, thus exploring the sensitivity of our results to these different choices and to the flavor dependence of parton fragmentation functions. We discuss how experimental measurements could discriminate among the various scenarios.Comment: 33 pages, 10 composite figures, JHEP style fil

    Matching factorization theorems with an inverse-error weighting

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    We propose a new fast method to match factorization theorems applicable in different kinematical regions, such as the transverse-momentum-dependent and the collinear factorization theorems in Quantum Chromodynamics. At variance with well-known approaches relying on their simple addition and subsequent subtraction of double-counted contributions, ours simply builds on their weighting using the theory uncertainties deduced from the factorization theorems themselves. This allows us to estimate the unknown complete matched cross section from an inverse-error-weighted average. The method is simple and provides an evaluation of the theoretical uncertainty of the matched cross section associated with the uncertainties from the power corrections to the factorization theorems (additional uncertainties, such as the nonperturbative ones, should be added for a proper comparison with experimental data). Its usage is illustrated with several basic examples, such as Z boson, W boson, H0 boson and Drell–Yan lepton-pair production in hadronic collisions, and compared to the state-of-the-art Collins–Soper–Sterman subtraction scheme. It is also not limited to the transverse-momentum spectrum, and can straightforwardly be extended to match any (un)polarized cross section differential in other variables, including multi-differential measurements

    System and method for real time remote measurement of geometric parameters of a pipeline in the launch step, through sound waves

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    A system for real time remote measurement, through sound waves, of geometric parameters of a pipeline in the launch step is described. System comprises an acoustic transceiver unit which can be positioned in pipeline , and a control unit. The acoustic transceiver comprises an acoustic transmission configured to emit an input acoustic signal sa1 into pipeline 2, based on an electric pilot signal sp; and further comprises an acoustic receiving unit 5, distinct from the acoustic transmission unit 4, configured to detect the input acoustic signal sa1 and to generate a first electric measurement signal se1, dependent on the input acoustic signal sa1 The acoustic receiving unit 5 is further configured to receive an input return signal sa2, generated in pipeline 2 and dependent on the input acoustic signal sa1 and on the geometric parameters of pipeline 2, and to generate a second electric measurement signal se2 based on the return acoustic signal sa2. The control unit 3 is configured to generate the electric pilot signal sp and is operatively connected to the acoustic transceiver unit 1 to provide the electric pilot signal sp and to receive the first electric measurement signal se1 and the second electric measurement signal se2. Furthermore, the control unit 3 is configured to measure the geometric parameters of pipeline 2 based on the first and second electric measurement signals (se1, se2 ). A method for real time remote measurement, through sound waves, of geometric parameters of a pipeline 2 in the launch step is further described, which can be carried out by the aforesaid system 10

    Microbial diversity and community structure across environmental gradients in Bransfield Strait, Western Antarctic Peninsula

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    © The Author(s), 2014. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Frontiers in Microbiology 5 (2014): 647, doi:10.3389/fmicb.2014.00647.The Southern Ocean is currently subject to intense investigations, mainly related to its importance for global biogeochemical cycles and its alarming rate of warming in response to climate change. Microbes play an essential role in the functioning of this ecosystem and are the main drivers of the biogeochemical cycling of elements. Yet, the diversity and abundance of microorganisms in this system remain poorly studied, in particular with regards to changes along environmental gradients. Here, we used amplicon sequencing of 16S rRNA gene tags using primers covering both Bacteria and Archaea to assess the composition and diversity of the microbial communities from four sampling depths (surface, the maximum and minimum of the oxygen concentration, and near the seafloor) at 10 oceanographic stations located in Bransfield Strait [northwest of the Antarctic Peninsula (AP)] and near the sea ice edge (north of the AP). Samples collected near the seafloor and at the oxygen minimum exhibited a higher diversity than those from the surface and oxygen maximum for both bacterial and archaeal communities. The main taxonomic groups identified below 100 m were Thaumarchaeota, Euryarchaeota and Proteobacteria (Gamma-, Delta-, Beta-, and Alphaproteobacteria), whereas in the mixed layer above 100 m Bacteroidetes and Proteobacteria (mainly Alpha- and Gammaproteobacteria) were found to be dominant. A combination of environmental factors seems to influence the microbial community composition. Our results help to understand how the dynamic seascape of the Southern Ocean shapes the microbial community composition and set a baseline for upcoming studies to evaluate the response of this ecosystem to future changes.This work was supported by the Brazilian National Counsel of Technological and Scientific Development (Polar Canion CNPq 556848/2009-8, ProOasis CNPq 565040/2010-3, Interbiota CNPq 407889/2013-2 and INCT-MAR-COI). Alex Enrich-Prast received a CNPq Productivity fellowship. Camila N. Signori was supported by a WHOI Mary Sears Visitor Award (for the microbial community analyses) and by the Brazilian Federal Agency for Support and Evaluation of Graduate Education (CAPES) for the “Doctorate Sandwich” scholarship (n. 18835/12-0)

    Unpolarized transverse momentum distributions from a global fit of Drell-Yan and semi-inclusive deep-inelastic scattering data

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    We present an extraction of unpolarized transverse-momentum-dependent parton distribution and fragmentation functions based on more than two thousand data points from several experiments for two different processes: semi-inclusive deep-inelastic scattering and Drell-Yan production. The baseline analysis is performed using the Monte Carlo replica method and resumming large logarithms at (NLL)-L-3 accuracy. The resulting description of the data is very good (chi(2)/N-dat = 1.06). For semi-inclusive deep-inelastic scattering, predictions for multiplicities are normalized by factors that cure the discrepancy with data introduced by higher-order perturbative corrections

    Gene electrotransfer of IL-2 and IL-12 plasmids effectively eradicated murine B16.F10 melanoma

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    Gene therapy has become an important approach for treating cancer, and electroporation represents a technology for introducing therapeutic genes into a cell. An example of cancer gene therapy relying on gene electrotransfer is the use of immunomodulatory cytokines, such as interleukin 2 (IL-2) and 12 (IL-12), which directly stimulate immune cells at the tumour site. The aim of our study was to determine the effects of gene electrotransfer with two plasmids encoding IL-2 and IL-12 in vitro and in vivo. Two different pulse protocols, known as EP1 (600 V/cm, 5 ms, 1 Hz, 8 pulses) and EP2 (1300 V/cm, 100 ”s, 1 Hz, 8 pulses), were assessed in vitro for application in subsequent in vivo experiments. In the in vivo experiment, gene electrotransfer of pIL-2 and pIL-12 using the EP1 protocol was performed in B16.F10 murine melanoma. Combined treatment of tumours using pIL2 and pIL12 induced significant tumour growth delay and 71% complete tumour regression. Furthermore, in tumours coexpressing IL-2 and IL-12, increased accumulation of dendritic cells and M1 macrophages was obtained along with the activation of proinflammatory signals, resulting in CD4 + and CD8 + T-lymphocyte recruitment and immune memory development in the mice. In conclusion, we demonstrated high antitumour efficacy of combined IL-2 and IL-12 gene electrotransfer protocols in low-immunogenicity murine B16.F10 melanoma
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