245 research outputs found

    At work and play; business events as entrepreneurial spaces

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    There is inadequate literature examining, and illustrating, the integration of play and business events and how this facilitates entrepreneurial opportunities. Business events are distinct from the patterns of ordinary life and increasingly offer participants an ‘invitation to play’, encouraging socialization and trust. This article examines the role of play in the design of business events and how this can enable entrepreneurial outcomes. Through examination of diverse, but related, literature and three contrasting, empirically based, case studies, this article illustrates how event creators take an increasingly entrepreneurial approach. These cases range from a charity event with participants sleeping with the homeless on a city’s streets, a major flooring manufacturer designing events to outsource innovation and an imaginative event activity termed ‘coffee and papers’. Designing events that fuse, rather than polarize, play and work enables business event settings, and activities, which trigger entrepreneurial outcomes. This article adds to the embryonic literature and concludes by identifying four principles that underlie the effectual facilitation of play in a business event setting

    Different Prey Resources Suggest Little Competition Between Non-Native Frogs and Insectivorous Birds Despite Isotopic Niche Overlap

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    Non-native amphibians often compete with native amphibians in their introduced range, but their competitive effects on other vertebrates are less well known. The Puerto Rican coqui frog (Eleutherodactylus coqui) has colonized the island of Hawaii, and has been hypothesized to compete with insectivorous birds and bats. To address if the coqui could compete with these vertebrates, we used stable isotope analyses to compare the trophic position and isotopic niche overlap between the coqui, three insectivorous bird species, and the Hawaiian hoary bat. Coquis shared similar trophic position to Hawaii amakihi, Japanese white-eye, and red-billed leiothrix. Coquis were about 3 ‰ less enriched in ή15N than the Hawaiian hoary bat, suggesting the bats feed at a higher trophic level than coquis. Analyses of potential diet sources between coquis and each of the three bird species indicate that there was more dietary overlap between bird species than any of the birds and the coqui. Results suggest that Acari, Amphipoda, and Blattodea made up \u3e90% of coqui diet, while Araneae made up only 2% of coqui diet, but approximately 25% of amakihi and white-eye diet. The three bird species shared similar proportions of Lepidoptera larvae, which were ~25% of their diet. Results suggest that coquis share few food resources with insectivorous birds, but occupy a similar trophic position, which could indicate weak competition. However, resource competition may not be the only way coquis impact insectivorous birds, and future research should examine whether coqui invasions are associated with changes in bird abundance

    Observation of an Exotic S=+1S=+1 Baryon in Exclusive Photoproduction from the Deuteron

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    In an exclusive measurement of the reaction Îłd→K+K−pn\gamma d \to K^+ K^- p n, a narrow peak that can be attributed to an exotic baryon with strangeness S=+1S=+1 is seen in the K+nK^+n invariant mass spectrum. The peak is at 1.542±0.0051.542\pm 0.005 GeV/c2^2 with a measured width of 0.021 GeV/c2^2 FWHM, which is largely determined by experimental mass resolution. The statistical significance of the peak is 5.2±0.6σ5.2 \pm 0.6 \sigma. The mass and width of the observed peak are consistent with recent reports of a narrow S=+1S=+1 baryon by other experimental groups.Comment: 5 pages, 5 figure

    Two-Nucleon Momentum Distributions Measured in 3He(e,e'pp)n

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    We have measured the 3He(e,e'pp)n reaction at 2.2 GeV over a wide kinematic range. The kinetic energy distribution for `fast' nucleons (p > 250 MeV/c) peaks where two nucleons each have 20% or less, and the third nucleon has most of the transferred energy. These fast pp and pn pairs are back-to-back with little momentum along the three-momentum transfer, indicating that they are spectators. Experimental and theoretical evidence indicates that we have measured distorted two-nucleon momentum distributions by striking the third nucleon and detecting the spectator correlated pair.Comment: 6 pages, 5 figures, submitted to PR

    Survey of A_LT' asymmetries in semi-exclusive electron scattering on He4 and C12

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    Single spin azimuthal asymmetries A_LT' were measured at Jefferson Lab using 2.2 and 4.4 GeV longitudinally polarized electrons incident on He4 and C12 targets in the CLAS detector. A_LT' is related to the imaginary part of the longitudinal-transverse interference and in quasifree nucleon knockout it provides an unambiguous signature for final state interactions (FSI). Experimental values of A_LT' were found to be below 5%, typically |A_LT'| < 3% for data with good statistical precision. Optical Model in Eikonal Approximation (OMEA) and Relativistic Multiple-Scattering Glauber Approximation (RMSGA) calculations are shown to be consistent with the measured asymmetries.Comment: 9 pages, 5 figure

    Onset of asymptotic scaling in deuteron photodisintegration

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    We investigate the transition from the nucleon-meson to quark-gluon description of the strong interaction using the photon energy dependence of the d(γ,p)nd(\gamma,p)n differential cross section for photon energies above 0.5 GeV and center-of-mass proton angles between 30∘30^{\circ} and 150∘150^{\circ}. A possible signature for this transition is the onset of cross section s−11s^{-11} scaling with the total energy squared, ss, at some proton transverse momentum, PTP_T. The results show that the scaling has been reached for proton transverse momentum above about 1.1 GeV/c. This may indicate that the quark-gluon regime is reached above this momentum.Comment: Accepted by PRL; 5 pages, 2 figure

    Observation of an Exotic Baryon with S=+1 in Photoproduction from the Proton

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    The reaction Îłp→π+K−K+n\gamma p \to \pi^+K^-K^+n was studied at Jefferson Lab using a tagged photon beam with an energy range of 3-5.47 GeV. A narrow baryon state with strangeness S=+1 and mass M=1555±10M=1555\pm 10 MeV/c2^2 was observed in the nK+nK^+ invariant mass spectrum. The peak's width is consistent with the CLAS resolution (FWHM=26 MeV/c2^2), and its statistical significance is 7.8 ±\pm 1.0 ~σ\sigma. A baryon with positive strangeness has exotic structure and cannot be described in the framework of the naive constituent quark model. The mass of the observed state is consistent with the mass predicted by a chiral soliton model for the Θ+\Theta^+ baryon. In addition, the pK+pK^+ invariant mass distribution was analyzed in the reaction Îłp→K−K+p\gamma p\to K^-K^+p with high statistics in search of doubly-charged exotic baryon states. No resonance structures were found in this spectrum.Comment: 5 pages, 5 figures, add reference

    Photodisintegration of 4^4He into p+t

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    The two-body photodisintegration of 4^4He into a proton and a triton has been studied using the CEBAF Large-Acceptance Spectrometer (CLAS) at Jefferson Laboratory. Real photons produced with the Hall-B bremsstrahlung-tagging system in the energy range from 0.35 to 1.55 GeV were incident on a liquid 4^4He target. This is the first measurement of the photodisintegration of 4^4He above 0.4 GeV. The differential cross sections for the γ\gamma4^4He→pt\to pt reaction have been measured as a function of photon-beam energy and proton-scattering angle, and are compared with the latest model calculations by J.-M. Laget. At 0.6-1.2 GeV, our data are in good agreement only with the calculations that include three-body mechanisms, thus confirming their importance. These results reinforce the conclusion of our previous study of the three-body breakup of 3^3He that demonstrated the great importance of three-body mechanisms in the energy region 0.5-0.8 GeV .Comment: 13 pages submitted in one tgz file containing 2 tex file and 22 postscrip figure

    π0\pi^0 photoproduction on the proton for photon energies from 0.675 to 2.875 GeV

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    Differential cross sections for the reaction Îłp→pπ0\gamma p \to p \pi^0 have been measured with the CEBAF Large Acceptance Spectrometer (CLAS) and a tagged photon beam with energies from 0.675 to 2.875 GeV. The results reported here possess greater accuracy in the absolute normalization than previous measurements. They disagree with recent CB-ELSA measurements for the process at forward scattering angles. Agreement with the SAID and MAID fits is found below 1 GeV. The present set of cross sections has been incorporated into the SAID database, and exploratory fits have been extended to 3 GeV. Resonance couplings have been extracted and compared to previous determinations.Comment: 18 pages, 48 figure

    Hyperon Photoproduction in the Nucleon Resonance Region

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    Cross-sections and recoil polarizations for the reactions gamma + p --> K^+ + Lambda and gamma + p --> K^+ + Sigma^0 have been measured with high statistics and with good angular coverage for center-of-mass energies between 1.6 and 2.3 GeV. In the K^+Lambda channel we confirm a structure near W=1.9 GeV at backward kaon angles, but our data shows a more complex s- and u- channel resonance structure than previously seen. This structure is present at forward and backward angles but not central angles, and its position and width change with angle, indicating that more than one resonance is playing a role. Rising back-angle cross sections at higher energies and large positive polarization at backward angles are consistent with sizable s- or u-channel contributions. None of the model calculations we present can consistently explain these aspects of the data.Comment: 5 pages, 3 figures, submitted to Physical Review Letter
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