643 research outputs found

    Manifestations of professional identity work: An integrative review of research in professional identity formation

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    Professional identity formation (PIF) is an integral part of educating professionals. A well-formed professional identity helps individuals to develop a meaningful professional self-understanding that facilitates their transition to and sustainability in professional work. Although professional identity and its formation are well theorized, it is largely unclear how the underpinning interpretive process of professional identity work leads to observable changes in thoughts, feelings and behaviours, and how these insights can be used in educational practice. To address this gap, we conducted an integrative review of 77 empirical articles on professional identity formation and inductively developed a four-fold typology of professional identity work, through which individuals reportedly make the shift from individual to professional. The theoretical contribution of this article is a more nuanced understanding of the practical manifestations of professional identity work. As a practical contribution, the typology may be used as a heuristic through which educators of professionals can support their students’ professional identity formation, particularly where this is halted or complicated by obstructions

    Configurations of Boundary Management Practices among Knowledge Workers

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    Acknowledgements: We thank all research participants for their contribution to our study. We also thank all colleagues for their constructive feedback on this article at different stages of development, particularly participants in sub-theme 35 of the 2017 EGOS Colloquium, Dr Susan Kirk, the Editor and the three anonymous reviewers. Funding information: Funding by British Academy and Leverhulme Trust under the Small Grant Scheme (award No. SG152296) for this research is gratefully acknowledgedPeer reviewedPublisher PD

    See a Black Hole on a Shoestring

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    The modes of vibration of hanging and partially supported strings provide useful analogies to scalar fields travelling through spacetimes that admit conformally flat spatial sections. This wide class of spacetimes includes static, spherically symmetric spacetimes. The modes of a spacetime where the scale factor depends as a power-law on one of the coordinates provide a useful starting point and yield a new classification of these spacetimes on the basis of the shape of the string analogue. The family of corresponding strings follow a family of curves related to the cycloid, denoted here as hypercycloids (for reasons that will become apparent). Like the spacetimes that they emulate these strings exhibit horizons, typically at their bottommost points where the string tension vanishes; therefore, hanging strings may provide a new avenue for the exploration of the quantum mechanics of horizons.Comment: 5 pages, 1 figure, extensive changes to refect version accepted to PR

    Electrically charged fluids with pressure in Newtonian gravitation and general relativity in d spacetime dimensions: theorems and results for Weyl type systems

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    Previous theorems concerning Weyl type systems, including Majumdar-Papapetrou systems, are generalized in two ways, namely, we take these theorems into d spacetime dimensions (d≄4{\rm d}\geq4), and we also consider the very interesting Weyl-Guilfoyle systems, i.e., general relativistic charged fluids with nonzero pressure. In particular within Newton-Coulomb theory of charged gravitating fluids, a theorem by Bonnor (1980) in three-dimensional space is generalized to arbitrary (d−1)>3({\rm d}-1)>3 space dimensions. Then, we prove a new theorem for charged gravitating fluid systems in which we find the condition that the charge density and the matter density should obey. Within general relativity coupled to charged dust fluids, a theorem by De and Raychaudhuri (1968) in four-dimensional spacetimes in rendered into arbitrary d>4{\rm d}>4 dimensions. Then a theorem, new in d=4{\rm d}=4 and d>4{\rm d}>4 dimensions, for Weyl-Guilfoyle systems, is stated and proved, in which we find the condition that the charge density, the matter density, the pressure, and the electromagnetic energy density should obey. This theorem comprises, as particular cases, a theorem by Gautreau and Hoffman (1973) and results in four dimensions by Guilfoyle (1999). Upon connection of an interior charged solution to an exterior Tangherlini solution (i.e., a Reissner-Nordstr\"om solution in d-dimensions), one is able to give a general definition for gravitational mass for this kind of relativistic systems and find a mass relation with the several quantities of the interior solution. It is also shown that for sources of finite extent the mass is identical to the Tolman mass.Comment: 27 page

    Orbital Selective Magnetism in the Spin-Ladder Iron Selenides Ba1−x_{1-x}Kx_{x}Fe2_2Se3_3

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    Here we show that the 2.80(8) {\mu}B/Fe block antiferromagnetic order of BaFe2Se3 transforms into stripe antiferromagnetic order in KFe2Se3 with a decrease in moment to 2.1(1) {\mu}B/Fe. This reduction is larger than expected from the change in electron count from Ba2+^{2+} to K+^{+}, and occurs with the loss of the displacements of Fe atoms from ideal positions in the ladders, as found by neutron pair distribution function analysis. Intermediate compositions remain insulating, and magnetic susceptibility measurements show a suppression of magnetic order and probable formation of a spin-glass. Together, these results imply an orbital-dependent selection of magnetic versus bonded behavior, driven by relative bandwidths and fillings.Comment: Final versio

    Black string and velocity frame dragging

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    We investigate velocity frame dragging with the boosted Schwarzschild black string solution and the boosted Kaluza-Klein bubble solution, in which a translational symmetry along the boosted zz-coordinate is implemented. The velocity frame dragging effect can be nullified by the motion of an observer using the boost symmetry along the z−z-coordinate if it is not compact. However, in spacetime with the compact z−z-coordinate, we show that the effect cannot be removed since the compactification breaks the global Lorentz boost symmetry. As a result, the comoving velocity is dependent on rr and the momentum parameter along the z−z-coordinate becomes an observer independent characteristic quantity of the black string and bubble solutions. The dragging induces a spherical ergo-region around the black string.Comment: 8 pages, no figure, some correction

    Quantum Corrections to the Reissner-Nordstrom and Kerr-Newman Metrics: Spin 1

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    A previous evaluation of one-photon loop corrections to the energy-momentum tensor has been extended to particles with unit spin and speculations are presented concerning general properties of such forms.Comment: 21 pages, 1 Figur

    Active gravitational mass and the invariant characterization of Reissner-Nordstrom spacetime

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    We analyse the concept of active gravitational mass for Reissner-Nordstrom spacetime in terms of scalar polynomial invariants and the Karlhede classification. We show that while the Kretschmann scalar does not produce the expected expression for the active gravitational mass, both scalar polynomial invariants formed from the Weyl tensor, and the Cartan scalars, do.Comment: 6 pages Latex, to appear in General Relativity and Gravitatio

    The Boundary Layer for the Reissner–Mindlin Plate Model

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    Classical and Quantum Analysis of Repulsive Singularities in Four Dimensional Extended Supergravity

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    Non--minimal repulsive singularities (``repulsons'') in extended supergravity theories are investigated. The short distance antigravity properties of the repulsons are tested at the classical and the quantum level by a scalar test--particle. Using a partial wave expansion it is shown that the particle gets totally reflected at the origin. A high frequency incoming particle undergoes a phase shift of π2\frac{\pi}{2}. However, the phase shift for a low--frequency particle depends upon the physical data of the repulson. The curvature singularity at a finite distance rhr_h turns out to be transparent for the scalar test--particle and the coordinate singularity at the origin serves as a repulsive barrier at which particles bounce off.Comment: 20 pages, 14 figure
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