152 research outputs found

    Spin constraints on Regge predictions and perturbative evolution in high energy collisions

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    Two key issues in the application of perturbative QCD and Regge predictions to high energy processes are whether the hard and soft pomerons should be considered as two separate distinct exchanges and whether the Regge intercepts are Q^2 independent or not. Models involving a distinct hard pomeron exchange predict much larger values for the LHC total cross-section. Here we argue that there is a polarized analogue of this issue in the isovector part of the spin structure function g_1 and that the spin data appear to favour a distinct hard exchange.Comment: 8 page

    Application of Silicon Carbide Chills in Controlling the Solidification Process of Casts Made of IN-713C Nickel Superalloy

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    The paper presents the method of manufacturing casts made of the IN-713C nickel superalloy using the wax lost investment castingprocess and silicon carbide chills. The authors designed experimental casts, the gating system and selected the chills material. Wax pattern,ceramic shell mould and experimental casts were prepared for the purposes of research. On the basis of the temperature distributionmeasurements, the kinetics of the solidification process was determined in the thickened part of the plate cast. This allowed to establish thequantity of phase transitions which occurred during cast cooling process and the approximate values of liquidus, eutectic, solidus andsolvus temperatures as well as the solidification time and the average value of cast cooling rate. Non-destructive testing and macroscopicanalysis were applied to determine the location and size of shrinkage defects. The authors present the mechanism of solidification andformation of shrinkage defects in casts with and without chills. It was found that the applied chills influence significantly the hot spots andthe remaining part of the cast. Their presence allows to create conditions for solidification of IN-713C nickel superalloy cast withoutshrinkage defects

    Augmented collisional ionization via excited states in XUV cluster interactions

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    The impact of atomic excited states is investigated via a detailed model of laser-cluster interactions, which is applied to rare gas clusters in intense femtosecond pulses in the extreme ultraviolet (XUV). This demonstrates the potential for a two-step ionization process in laser-cluster interactions, with the resulting intermediate excited states allowing for the creation of high charge states and the rapid dissemination of laser pulse energy. The consequences of this excitation mechanism are demonstrated through simulations of recent experiments in argon clusters interacting with XUV radiation, in which this two-step process is shown to play a primary role; this is consistent with our hypothesis that XUV-cluster interactions provide a unique window into the role of excited atomic states due to the relative lack of photoionization and laser field-driven phenomena. Our analysis suggests that atomic excited states may play an important role in interactions of intense radiation with materials in a variety of wavelength regimes, including potential implications for proposed studies of single molecule imaging with intense X-rays.Comment: 4 pages, 2 figure

    Intermittency for coherent and incoherent current ensemble model

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    We investigate the origin of intermittency for multiparticle distribution in momentum space, following the idea that there is a kind of power law distribution of the space-time region of hadron emission. Using the formalism of current ensamble model to describe boson sources we discuss intermittency exponents for the coherent and incoherent ( chaotic) particle production scheme.Comment: 13 pages, latex, no figure

    Zawartość metalicznych i niemetalicznych pierwiastków w homogenatach próbek tkankowych pobranych z amputowanych na poziomie uda z powodu miażdżycy kończyn dolnych. Doniesienie wstępne

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    Background: Metallic and non-metallic elements have influence on the development the changes within structure and function of arteries in different regions of vascular tree. The content of elements into arterial walls varies according to geographical origin of people. Material and methods: Tissue specimens were taken from the six lower limbs amputated on the level of thigh due to atherosclerosis. The mean age was 69 (57 to 84). Tissue specimens were collected from the limbs from the level of amputation, the popliteal fossa and the dorsal artery of foot. After chemical processing of the tissues homogenates determination of the content of elements using atomic emission spectrometry method with inductively coupled plasma (inductively coupled plasma optical emission spectroscopy) was performed. The content of Al, Ba, Ca, Cu, Fe, K, Mg, Mn, P, S, Sr and Zn was determined. Results: As a point of reference mean absolute value occurred from six specimens on the level of thigh was assumed as 100%. Content of non-metallic elements such as Ca, P and S rise towards to periphery of amputated limb reaching few times higher values on the level of dorsal artery of foot. Content of some metallic elements such as: Fe, Zn, K and Sr also rise towards to periphery of extremity. The Cu accumulation was the highest on the level of popliteal fossa, while Mn, Al and Mg concentration was the lowest on this same level and the highest in dorsal artery of foot. Conclusions: The influence of individual elements on development the atherosclerosis especially on necrotic changes requires further investigations. Described problem pose a preliminary report only in order to indicate the issue and to check the method of analysis

    TESLA Technical Design Report Part III: Physics at an e+e- Linear Collider

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    The TESLA Technical Design Report Part III: Physics at an e+e- Linear ColliderComment: 192 pages, 131 figures. Some figures have reduced quality. Full quality figures can be obtained from http://tesla.desy.de/tdr. Editors - R.-D. Heuer, D.J. Miller, F. Richard, P.M. Zerwa

    Novel Arenavirus Sequences in Hylomyscus sp. and Mus (Nannomys) setulosus from Côte d'Ivoire: Implications for Evolution of Arenaviruses in Africa

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    This study aimed to identify new arenaviruses and gather insights in the evolution of arenaviruses in Africa. During 2003 through 2005, 1,228 small mammals representing 14 different genera were trapped in 9 villages in south, east, and middle west of Côte d'Ivoire. Specimens were screened by pan-Old World arenavirus RT-PCRs targeting S and L RNA segments as well as immunofluorescence assay. Sequences of two novel tentative species of the family Arenaviridae, Menekre and Gbagroube virus, were detected in Hylomyscus sp. and Mus (Nannomys) setulosus, respectively. Arenavirus infection of Mus (Nannomys) setulosus was also demonstrated by serological testing. Lassa virus was not found, although 60% of the captured animals were Mastomys natalensis. Complete S RNA and partial L RNA sequences of the novel viruses were recovered from the rodent specimens and subjected to phylogenetic analysis. Gbagroube virus is a closely related sister taxon of Lassa virus, while Menekre virus clusters with the Ippy/Mobala/Mopeia virus complex. Reconstruction of possible virus–host co-phylogeny scenarios suggests that, within the African continent, signatures of co-evolution might have been obliterated by multiple host-switching events
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