19,210 research outputs found

    Integrating Employment Contracts and Comparisons: What One Can Teach Us about the Other

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    This study examines the events that trigger individuals to consider the social exchanges involved in their employment relationships. Integrating social comparison and psychological contract literature streams, a parallel is drawn between system-referent comparisons and psychological contract evaluations. We hypothesize that self- and other-referent comparisons may be human triggers for engaging in this type of comparison. A variety of structural triggers are also proposed to influence psychological contract evaluations. This field study examines these primary and secondary contract makers as social comparison triggers. Results support the hypotheses that the triggers identified predict psychological contract evaluation and that psychological contract breach is correlated with these evaluations. Implications for future research and managerial practice are discussed

    Mixed Meson Masses with Domain-Wall Valence and Staggered Sea Fermions

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    Mixed action lattice calculations allow for an additive lattice spacing dependent mass renormalization of mesons composed of one sea and one valence quark, regardless of the type of fermion discretization methods used in the valence and sea sectors. The value of the mass renormalization depends upon the lattice actions used. This mixed meson mass shift is an important lattice artifact to determine for mixed action calculations; because it modifies the pion mass, it plays a central role in the low energy dynamics of all hadronic correlation functions. We determine the leading order, O(a2)\mathcal{O}(a^2), and next to leading order, O(a2mπ2)\mathcal{O}(a^2 m_\pi^2), additive mass shift of \textit{valence-sea} mesons for a mixed lattice action with domain-wall valence fermions and rooted staggered sea fermions, relevant to the majority of current large scale mixed action lattice efforts. We find that on the asqtad improved coarse MILC lattices, this additive mass shift is well parameterized in lattice units by Δ(am)2=0.034(2)0.06(2)(amπ)2\Delta(am)^2 = 0.034(2) -0.06(2) (a m_\pi)^2, which in physical units, using a=0.125a=0.125 fm, corresponds to Δ(m)2=(291±8MeV)20.06(2)mπ2\Delta(m)^2 = (291\pm 8 \textrm{MeV})^2 -0.06(2) m_\pi^2. In terms of the mixed action effective field theory parameters, the corresponding mass shift is given by a2ΔMix=(316±4MeV)2a^2 \Delta_\mathrm{Mix} = (316 \pm 4 \textrm{MeV})^2 at leading order plus next-to-leading order corrections including the necessary chiral logarithms for this mixed action calculation, determined in this work. Within the precision of our calculation, one can not distinguish between the full next-to-leading order effective field theory analysis of this additive mixed meson mass shift and the parameterization given above.Comment: 28 pages, 3 figures, 5 table

    Northrop F-5F shark nose development

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    During spin susceptibility testing of the Northrop F-5F airplane, two erect spin entries were obtained from purely longitudinal control inputs at low speed. Post flight analysis of the data showed that the initial yaw departure occurred at zero sideslip, and review of wind tunnel data showed significant yawing moments present at angles of attack well above stall. Further analysis of this wind tunnel data indicated that the yawing moments were being generated by the long slender nose of the airplane. Redesign of the nose was accomplished, resulting in a nose configuration which completely alleviated the asymmetric yawing moments

    Global cross-over dynamics of single semiflexible polymers

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    We present a mean-field dynamical theory for single semiflexible polymers which can precisely capture, without fitting parameters, recent fluorescence correlation spectroscopy results on single monomer kinetics of DNA strands in solution. Our approach works globally, covering three decades of strand length and five decades of time: it includes the complex cross-overs occurring between stiffness-dominated and flexible bending modes, along with larger-scale rotational and center-of-mass motion. The accuracy of the theory stems in part from long-range hydrodynamic coupling between the monomers, which makes a mean-field description more realistic. Its validity extends even to short, stiff fragments, where we also test the theory through Brownian hydrodynamics simulations.Comment: 6 pages, 5 figures; updated with minor changes to reflect published versio

    Characterisation of small defects using miniaturised EMAT system

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    Many surface breaking defects, such as those caused by thermal fatigue or stress corrosion, have finite lateral dimensions. However, much of the research considers significantly larger simulated defects. This paper considers defects with mm-dimensions, and presents a method for characterisation of their length and depth. This is done using non-contact ultrasonic techniques, including a pair of electromagnetic acoustic transducers (EMATs) with significantly reduced size compared to standard industrial EMATs. Defects with dimensions of 1–11 mm length and 0.5–2 mm depth are measured. All information is obtained from a single raster scan of a sample, considering transmission and enhancement of Rayleigh waves, and introducing the defect cross-section. The lateral size resolution for the scan steps chosen is ± 1 mm, and depth resolution is ± 0.5 mm. The method, being non-contact, is also demonstrated on a sample with a 110 μm thick coating

    An eighth-century inscribed cross-slab in Dull, Perthshire

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    The discovery of a cross-inscribed slab with an inscription is described. Because of its importance it was decided to invite specialist comment on this piece of sculpture and to publish it in advance of the full report on the excavations. The form of the monument, its inscription and archaeological context are considered. The text appears to consist of a Gaelic personal name. The script is a form of geometrical lettering which can be dated to the opening quarter of the eighth century. The form of the cross has Columban associations which sit well with place-name and other evidence which points to Dull having been a monastery founded from Iona by c. AD 700

    Spontaneous flow states in active nematics: a unified picture

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    Continuum hydrodynamic models of active liquid crystals have been used to describe dynamic self-organising systems such as bacterial swarms and cytoskeletal gels. A key prediction of such models is the existence of self-stabilising kink states that spontaneously generate fluid flow in quasi-one dimensional channels. Using simple stability arguments and numerical calculations we extend previous studies to give a complete characterisation of the phase space for both contractile and extensile particles (ie pullers and pushers) moving in a narrow channel as a function of their flow alignment properties and initial orientation. This gives a framework for unifying many of the results in the literature. We describe the response of the kink states to an imposed shear, and investigate how allowing the system to be polar modifies its dynamical behaviour.Comment: 6 pages, 6 figures; submitted to Europhysics Letter

    Parametrization of the Driven Betatron Oscillation

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    An AC dipole is a magnet which produces a sinusoidally oscillating dipole field and excites coherent transverse beam motion in a synchrotron. By observing this coherent motion, the optical parameters can be directly measured at the beam position monitor locations. The driven oscillation induced by an AC dipole will generate a phase space ellipse which differs from that of the free oscillation. If not properly accounted for, this difference can lead to a misinterpretation of the actual optical parameters, for instance, of 6% or more in the cases of the Tevatron, RHIC, or LHC. The effect of an AC dipole on the linear optics parameters is identical to that of a thin lens quadrupole. By introducing a new amplitude function to describe this new phase space ellipse, the motion produced by an AC dipole becomes easier to interpret. Beam position data taken under the influence of an AC dipole, with this new interpretation in mind, can lead to more precise measurements of the normal Courant-Snyder parameters. This new parameterization of the driven motion is presented and is used to interpret data taken in the FNAL Tevatron using an AC dipole.Comment: 8 pages, 8 figures, and 1 tabl

    Stamping the Royal Seal with DNA Methylation

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    V. problem presentation and advice-giving on a home birth helpline

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    The rate of home births in the UK is very low (around 2%) and many women who would like to give birth at home find it impossible to get midwifery cover or are advised of medical contraindications. The Home Birth Helpline offers support and expertise for women in this situation. Based on the analysis of 80 recorded calls, this article uses conversation analysis (CA) to explore how callers present their reason for calling the helpline, and what this shows about the culturally shared medicalized culture of birth. This research is an example of feminist CA in that it contributes both to the study of childbirth as a key women's health issue and to the study of helpline interaction from a conversation analytic perspectiv
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