12,724 research outputs found

    The small xx behavior of the gluon structure function from total cross sections

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    Within a QCD-based eikonal model with a dynamical infrared gluon mass scale we discuss how the small xx behavior of the gluon distribution function at moderate Q2Q^{2} is directly related to the rise of total hadronic cross sections. In this model the rise of total cross sections is driven by gluon-gluon semihard scattering processes, where the behavior of the small xx gluon distribution function exhibits the power law xg(x,Q2)=h(Q2)x−ϵxg(x,Q^2)= h(Q^2)x^{-\epsilon}. Assuming that the Q2Q^{2} scale is proportional to the dynamical gluon mass one, we show that the values of h(Q2)h(Q^2) obtained in this model are compatible with an earlier result based on a specific nonperturbative Pomeron model. We discuss the implications of this picture for the behavior of input valence-like gluon distributions at low resolution scales.Comment: 19 pages, 3 figures; revised version; to appear in Int. J. Mod. Phys.

    A QCD sum rule calculation of the X±(5568)→Bs0π±X^\pm(5568) \to B_{s}^0\pi^\pm decay width

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    To understand the nature of the X(5568)X(5568), recently observed in the mass spectrum of the Bs0π±B_{s}^0\pi^\pm system by the D0 Collaboration, we have investigated, in a previous work, a scalar tetraquark (diquak-antidiquark) structure for it, within the two-point QCD sum rules method. The result found for its mass agrees well with the experimental value. Encouraged by this finding we now extend our calculations to obtain the decay width of X(5568)X(5568) to Bs0π±B_{s}^0\pi^\pm using the three-point QCD sum rule. We obtain a value of (20.4\pm8.7)\MeV, which, on comparing with the experimental value of 21.9\pm6.4 (\mbox{sta})^{+5.0}_{-2.5}(\mbox{syst}) \MeV/c^2, reinforces the scalar four quark nature of X(5568)X(5568).Comment: Minor modifications made. Some new discussions and references adde

    Spatial Variation in Erosion Rates in Mars Equatorial Regions Inferred from Ejecta Retention of 1-3 Km Diameter Craters

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    The modification of impact craters has long been used to infer the geomorphic forcing on Mars [1], as well as estimate the spatial and temporal variability of this erosion and gradation [e.g., 2]. Here, we studied the population of small primary craters (1-3 km) to understand differences in ejecta retention across equatorial Mars. Specifically, we evaluated whether craters in our study population had observable ejecta deposits (defined on the basis of distinct tone or texture with respect to their surroundings).This is a proxy for the resurfacing rate because only relatively fresh craters retain their ejecta deposits. More broadly, this is part of a larger project we are undertaking [3] to examine crater morphometry and other characteristics from CTX-derived digital terrain models (DTMs), augmented by qualitative observations

    TLEP, first step in a long-term vision for HEP

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    The discovery of H(126) has renewed interest in circular e+e- colliders that can operate as Higgs factories, which benefit from three unique characteristics: i) high luminosity and reliability, ii) the availability of several interaction points, iii) superior beam energy accuracy. TLEP is an e+e- storage ring of 80-km circumference that can operate with very high luminosity from the Z peak (90 GeV) to the top quark pair threshold (350 GeV). It can achieve transverse beam polarization at the Z peak and WW threshold, giving it unparalleled accuracy on the beam energy. A preliminary study indicates that an 80 km tunnel could be constructed around CERN. Such a tunnel would allow a 100 TeV proton-proton collider to be established in the same ring (VHE-LHC), offering a long term vision.Comment: This is a contribution to the the Snowmass process 2013: Frontier Capabilitie

    Comments on "Wall-plug (AC) power consumption of a very high energy e+/e- storage ring collider" by Marc Ross

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    The paper arXiv:1308.0735 questions some of the technical assumptions made by the TLEP Steering Group when estimating in arXiv:1305.6498 the power requirement for the very high energy e+e- storage ring collider TLEP. We show that our assumptions are based solidly on CERN experience with LEP and the LHC, as well accelerators elsewhere, and confirm our earlier baseline estimate of the TLEP power consumption.Comment: 6 page

    Gene expression profiling of Mycobacterium avium subsp. paratuberculosis in simulated multi-stress conditions and within THP-1 cells reveals a new kind of interactive intramacrophage behaviour

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    Recent studies have identified in Mycobacterium avium subsp. paratuberculosis (MAP), already known as a pathogen in ruminants, a potential zoonotic agent of some autoimmune diseases in humans. Therefore, considering the possible risk for public health, it is necessary a thorough understanding of MAP's gene expression during infection of human host as well as the identification of its immunogenic and/or virulence factors for the development of appropriate diagnostic and therapeutic tools.In order to characterize MAP's transcriptome during macrophage infection, we analyzed for the first time the whole gene expression of a human derived strain of MAP in simulated intraphagosomal conditions and after intracellular infection of the human macrophage cell line THP-1 by using the DNA-microarray technology. Results showed that MAP shifts its transcriptome to an adaptive metabolism for an anoxic environment and nutrient starvation. It up-regulates several response factors to oxidative stress or intracellular conditions and allows, in terms of transcription, a passive surface peptidoglycan spoliation within the macrophage along with an intensification of the anabolic activity for lipidic membrane structures.These results indicate a possible interactive system between MAP and its host cell based on the internal mimicry unlike other intracellular pathogens, bringing new hypothesis in the virulence and pathogenicity of MAP and its importance in human health

    Fruit sector strategic management: An exploration of agro-food chain actors' perception of market sustainability of apple innovation

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    The fresh fruit industry is a highly dynamic sector in the food market. Fresh fruit chain actors have to adapt to the changing market environment in order to face upcoming challenges. The objective of this study is to analyze the market sustainability of red-fleshed apples (RFA) by exploring consumers' and fresh fruit industry experts' and stakeholders' opinions in Italy and New Zealand. The study was carried out in Italy and New Zealand from December 2018 to June 2019 including 778 consumers and 29 expert and stakeholder interviews. Results show a promising market potential of RFA. Innovative attributes and nutritional value of RFA are the most important factors that push consumers' interest and willingness to buy RFA. New Zealand consumers and women show a higher appreciation of RFA. The nutritional value of the fruit can be a strategic marketing management attribute especially for health-conscious consumers. However, experts think the market for RFA will develop slowly, and will remain a niche product. Some stakeholders are skeptical about consumer RFA appreciation, and fear that RFA are too radical a novelty on the market. The RFA may be perceived as not natural. There is the need to coordinate food chain stakeholders' management practices on RFA. This allows to mitigate risks, set food standards acceptable for all chain stakeholders, and make sustainable economic investment on innovation

    Elastic scattering and the proton form factor

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    We compute the differential and the total cross sections for pppp scattering using the QCD pomeron model proposed by Landshoff and Nachtmann. This model is quite dependent on the experimental electromagnetic form factor, and it is not totally clear why this form factor gives good results even at moderate transferred momentum. We exchange the eletromagnetic form factor by the asymptotic QCD proton form factor determined by Brodsky and Lepage (BL) plus a prescription for its low energy behavior dictated by the existence of a dynamically generated gluon mass. We fit the data with this QCD inspired form factor and a value for the dynamical gluon mass consistent with the ones determined in the literature. Our results also provide a new determination of the proton wave function at the origin, which appears in the BL form factor.Comment: 10 pages, 2 figures. Submitted to Physics Letters B. Submitted to Phys. Lett.
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