130 research outputs found

    Using tourism free-choice learning experiences to promote environmentally sustainable behaviour: The role of post-visit ‘action resources’

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    This paper argues the need for the providers of ecotourism and other free‐choice environmental learning experiences to promote the adoption of environmentally sustainable actions beyond their own sites, when visitors return to their home environments. Previous research indicates that although visitors often leave such experiences with a heightened awareness of conservation issues and intentions to adopt environmentally responsible behaviours, only a minority translate these intentions into real actions. Building on research and theory in relation to visitor experiences in free‐choice learning environments, the paper identifies three different stages in the educational process and proposes a strategy for facilitating the translation of visitors' behavioural intentions into the adoption of sustainable actions through the provision of post‐visit action resources

    Equivalence Theorem and Probing the Electroweak Symmetry Breaking Sector

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    We examine the Lorentz non-invariance ambiguity in longitudinal weak-boson scatterings and the precise conditions for the validity of the Equivalence Theorem (ET). {\it Safe} Lorentz frames for applying the ET are defined, and the intrinsic connection between the longitudinal weak-boson scatterings and probing the symmetry breaking sector is analyzed. A universal precise formulation of the ET is presented for both the Standard Model and the Chiral Lagrangian formulated Electro-Weak Theories. It is shown that in electroweak theories with strongly interacting symmetry breaking sector, the longitudinal weak-boson scattering amplitude {\it under proper conditions} can be replaced by the corresponding Goldstone-boson scattering amplitude in which all the internal weak-boson lines and fermion loops are ignored.Comment: 20 pages, in LaTeX, to appear in Phys. Rev. D (1995). A few minor corrections were made to clarify our viewpoint of the Equivalence Theorem and compare our conclusion with those in the literatur

    Convergence of a penalty-finite element approximation for an obstacle problem

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    This study establishes an error estimate for a penalty-finite element approximation of the variational inequality obtained by a class of obstacle problems. By special identification of the penalty term, we first show that the penalty solution converges to the solution of a mixed formulation of the variational inequality. The rate of convergence of the penalization is ɛ where ɛ is the penalty parameter. To obtain the error of finite element approximation, we apply the results obtained by Brezzi, Hager and Raviart for the mixed finite element method to the variational inequality.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46320/1/211_2005_Article_BF01396189.pd

    Hadronic B Decays Involving Even Parity Charmed Mesons

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    Hadronic B decays containing an parity-even charmed meson in the final state are studied. Specifically we focus on the Cabibbo-allowed decays Bˉ→D∗∗π(ρ),D∗∗Dˉs(∗),Dˉs∗∗D(∗)\bar B\to D^{**} \pi(\rho), D^{**}\bar D_s^{(*)}, \bar D^{**}_sD^{(*)} and Bˉs→Ds∗∗π(ρ)\bar B_s\to D_s^{**}\pi(\rho), where D∗∗D^{**} denotes generically a p-wave charmed meson. The B→D∗∗B\to D^{**} transition form factors are studied in the improved version of the Isgur-Scora-Grinstein-Wise quark model. We apply heavy quark effective theory and chiral symmetry to study the strong decays of p-wave charmed mesons and determine the magnitude of the D11/2−D13/2D_1^{1/2}-D_1^{3/2} mixing angle. Except the decay to D1(2427)0π−D_1(2427)^0\pi^- the predictions for B−→D∗∗0π−B^-\to D^{**0}\pi^- agree with experiment. The sign of D11/2−D13/2D_1^{1/2}-D_1^{3/2} mixing angle is found to be positive in order to avoid a severe suppression on the production of D1(2427)0π−D_1(2427)^0\pi^-. The interference between color-allowed and color-suppressed tree amplitudes is expected to be destructive in the decay B−→D1(2427)0π−B^-\to D_1(2427)^0\pi^-. Hence, an observation of the ratio D1(2427)0π−/D1(2427)+π−D_1(2427)^0\pi^-/D_1(2427)^+\pi^- can be used to test the relative signs of various form factors as implied by heavy quark symmetry. Although the predicted B−→D1(2420)0ρ−B^-\to D_1(2420)^0\rho^- at the level of 3×10−33\times 10^{-3} exceeds the present upper limit, it leads to the ratio D1(2420)ρ−/D1(2420)π−≈2.6D_1(2420)\rho^-/D_1(2420)\pi^-\approx 2.6 as expected from the factorization approach and from the ratio fρ/fπ≈1.6f_\rho/f_\pi\approx 1.6 . Therefore, it is crucial to have a measurement of this mode to test the factorization hypothesis. For Bˉ→Dˉs∗∗D\bar B\to \bar D_s^{**}D decays, it is expected that \bar D_{s0}^*D\gsim \bar D_{s1}D as the decay constants of the multiplet (Ds0∗,Ds1)(D_{s0}^*,D_{s1}) become the same in the heavy quark limit.Comment: 27 pages, Belle's new data on DD_s^{**} productions in B decays and on the radiative decay D_{s1}-> D_s\gamma are updated and discussed. Add two reference

    Rare Charm Decays in the Standard Model and Beyond

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    We perform a comprehensive study of a number of rare charm decays, incorporating the first evaluation of the QCD corrections to the short distance contributions, as well as examining the long range effects. For processes mediated by the c→uℓ+ℓ−c\to u\ell^+\ell^- transitions, we show that sensitivity to short distance physics exists in kinematic regions away from the vector meson resonances that dominate the total rate. In particular, we find that D→πℓ+ℓ−D\to\pi\ell^+\ell^- and D→ρℓ+ℓ−D\to\rho\ell^+\ell^- are sensitive to non-universal soft-breaking effects in the Minimal Supersymmetric Standard Model with R-parity conservation. We separately study the sensitivity of these modes to R-parity violating effects and derive new bounds on R-parity violating couplings. We also obtain predictions for these decays within extensions of the Standard Model, including extensions of the Higgs, gauge and fermion sectors, as well as models of dynamical electroweak symmetry breaking.Comment: 45 pages, typos fixed, discussions adde

    Thermal desorption of CH4 retained in CO2 ice

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    CO2 ices are known to exist in different astrophysical environments. In spite of this, its physical properties (structure, density, refractive index) have not been as widely studied as those of water ice. It would be of great value to study the adsorption properties of this ice in conditions related to astrophysical environments. In this paper, we explore the possibility that CO2 traps relevant molecules in astrophysical environments at temperatures higher than expected from their characteristic sublimation point. To fulfil this aim we have carried out desorption experiments under High Vacuum conditions based on a Quartz Crystal Microbalance and additionally monitored with a Quadrupole Mass Spectrometer. From our results, the presence of CH4 in the solid phase above the sublimation temperature in some astrophysical scenarios could be explained by the presence of several retaining mechanisms related to the structure of CO2 ice.Comment: 8 pages, accepted for publication in Astrophysics & Space Scienc

    Q

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    The Qweak experiment, which took data at Jefferson Lab in the period 2010 - 2012, will precisely determine the weak charge of the proton by measuring the parity-violating asymmetry in elastic e-p scattering at 1.1 GeV using a longitudinally polarized electron beam and a liquid hydrogen target at a low momentum transfer of Q2 = 0.025 (GeV/c)2. The weak charge of the proton is predicted by the Standard Model and any significant deviation would indicate physics beyond the Standard Model. The technical challenges and experimental apparatus for measuring the weak charge of the proton will be discussed, as well as the method of extracting the weak charge of the proton. The results from a small subset of the data, that has been published, will also be presented. Furthermore an update will be given of the current status of the data analysis

    A Historiometric Examination of Machiavellianism and a New Taxonomy of Leadership

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    Although researchers have extensively examined the relationship between charismatic leadership and Machiavellianism (Deluga, 2001; Gardner & Avolio, 1995; House & Howell, 1992), there has been a lack of investigation of Machiavellianism in relation to alternative forms of outstanding leadership. Thus, the purpose of this investigation was to examine the relationship between Machiavellianism and a new taxonomy of outstanding leadership comprised of charismatic, ideological, and pragmatic leaders. Using an historiometric approach, raters assessed Machiavellianism via the communications of 120 outstanding leaders in organizations across the domains of business, political, military, and religious institutions. Academic biographies were used to assess twelve general performance measures as well as twelve general controls and five communication specific controls. The results indicated that differing levels of Machiavellianism is evidenced across the differing leader types as well as differing leader orientation. Additionally, Machiavellianism appears negatively related to performance, though less so when type and orientation are taken into account.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

    Environmental Design for Patient Families in Intensive Care Units

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