7,839 research outputs found

    Limits on a Strong Electroweak Sector from e^+ e^- -> 2gamma + missing E at LEP2

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    We study the process e+eγγννˉe^+ e^- \to \gamma \gamma \nu \bar{\nu} in the context of a strong electroweak symmetry breaking model, which can be a source of events with two photons and missing energy at LEP2. We investigate bounds on the model assuming that no deviation is observed from the Standard Model within a given experimental error.Comment: 7 pages, Latex, one figur

    Zinc(II) coordination polymers with pseudopeptidic ligands

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    Two new phenyl-bridged pseudopeptidic ligands have been prepared and structurally characterised. The nature of the ligands’ substituents play an important role in the nature of the solid state structure yielding either hydrogen bonded linked sheets of molecules or infinite hydrogen bonded networks. Both these ligands were reacted with a range of zinc(II) salts with the aim of synthesising coordination polymers and networks and exploring the role that anions could play in determining the final structure. The crystal structures of four of these systems (with ZnSO4 and ZnBr2) were determined; in one case, a 3D coordination network was obtained where zinc–ligand coordination bonds generated the 3D arrangements. Three other 3D networks were obtained by anion-mediated hydrogen bonding of coordination 1D chains or 2D sheets. These four very different structures highlight the important role played by the ligands’ substituents and the counteranions present in the system

    Assessing strength and power in resistance training

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    Maximal Dynamic Strength is usually assessed either by the one repetition maximum test (1-RM) or by a repetition maximum test with submaximal loads, which requires the application of a formula to estimate the value of 1-RM. This value is needed to establish the objective of resistance training: such as maximum strength, endurance strength, and/or explosive strength. However, both 1-RM and submaximal tests are unable to highlight the changes produced on power and velocity. This manuscript summarizes and reviews several common strength testing protocols and proposes a novel approach that may offer greater insight to hierarchical muscle functionalit

    Impact of Power Allocation and Antenna Directivity in the Capacity of a Multiuser Cognitive Ad Hoc Network

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    This paper studies the benefits that power control and antenna directivity can bring to the capacity of a multiuser cognitive radio network. The main objective is to optimize the secondary network sum rate under the capacity constraint of the primary network. Exploiting location awareness, antenna directivity, and the power control capability, the cognitive radio ad hoc network can broaden its coverage and improve capacity. Computer simulations show that by employing the proposed method the system performance is significantly enhanced compared to conventional fixed power allocation

    Saturated Critical Heat Flux in a Multi-Microchannel Heat Sink Fed by a Split Flow System

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    An extensive experimental campaign has been carried out for the measurement of saturated critical heat flux in a multi-microchannel copper heat sink. The heat sink was formed by 29 parallel channels that were 199 μm wide and 756 μm deep. In order to increase the critical heat flux and reduce the two-phase pressure drop, a split flow system was implemented with one central inlet at the middle of the channels and two outlets at either end. The base critical heat flux was measured using three HFC Refrigerants (R134a, R236fa and R245fa) for mass fluxes ranging from 250 to 1500 kg/m2 s, inlet subcoolings from −25 to −5 K and saturation temperatures from 20 to 50 °C. The parametric effects of mass velocity, saturation temperature and inlet subcooling were investigated. The analysis showed that significantly higher CHF was obtainable with the split flow system (one inlet–two outlets) compared to the single inlet–single outlet system, providing also a much lower pressure drop. Notably several existing predictive methods matched the experimental data quite well and quantitatively predicted the benefit of higher CHF of the split flow

    Racial Constructions and Activism Within Graphic Literature. An Analysis of Hank McCoy, The Beast

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    Through a post-modern lens, I will primarily focus on comics books published by Marvel Comics to demonstrate the myriad of ways in which graphic literature is used as a subversive tool of sociopolitical discourse. I will demonstrate this by deconstructing and redefining the role of myth as a means of transferring ethical practices through societies and the ways in which graphic literature serves this function within the space of a modern and increasingly atheistic society. The thesis first demonstrates how the American Civil Rights Movement was metaphorically translated and depicted to the pages of Marvel’s X-Men comics to expose its primarily white/ male readership to the plight of discriminated Black Americans through the juxtaposition of depicting white super heroes who represented the segregated experiences of othered or unwanted communities. Secondly, the X-Man Beast is closely analyzed to demonstrate the ways in which the rhetoric and depictions of graphic literature are altered through decades of publication to adapt its messages of social tolerance and peaceful coexistence to its contemporary audiences

    Finite VEVs from a Large Distance Vacuum Wave Functional

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    We show how to compute vacuum expectation values from derivative expansions of the vacuum wave functional. Such expansions appear to be valid only for slowly varying fields, but by exploiting analyticity in a complex scale parameter we can reconstruct the contribution from rapidly varying fields.Comment: 39 pages, 16 figures, LaTeX2e using package graphic
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