5,067 research outputs found

    Managerial Skill Acquisition and the Theory of Economic Development

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    Micro level studies in developing countries suggest managerial skills play a key role in the adoption of modern technologies. The human resources literature suggests that managerial skills are difficult to codify and learn formally, but instead tend to be learned on the job. In this paper we present a model of the interactive process between on-the-job managerial skill acquisition and the adoption of modern technology. The environment considered is one where all learning possibilities are internalized in the market, and where managers are complementary inputs to non-managerial workers. The paper illustrates why some countries may adopt modern technologies while others stay backwards. The paper also explains why managers may not want to migrate from rich countries to poor countries as would be needed to generate income convergence.

    On the cohomology algebra of some classes of geometrically formal manifolds

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    We investigate harmonic forms of geometrically formal metrics, which are defined as those having the exterior product of any two harmonic forms still harmonic. We prove that a formal Sasakian metric can exist only on a real cohomology sphere and that holomorphic forms of a formal K\"ahler metric are parallel w.r.t. the Levi-Civita connection. In the general Riemannian case a formal metric with maximal second Betti number is shown to be flat. Finally we prove that a six-dimensional manifold with b11,b22b_1 \neq 1, b_2 \geqslant 2 and not having the cohomology algebra of T3×S3\mathbb{T}^3 \times S^3 carries a symplectic structure as soon as it admits a formal metric.Comment: Final version. Accepted in Proc.London Math.So

    The Black Hole Entropy Can Be Smaller than A/4

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    The coupling of a Nambu-Goto string to gravity allows for Schwarzschild black holes whose entropy to area relation is S=(A/4)(14μ)S=(A/4)(1-4\mu), where μ\mu is the string tension.Comment: LaTeX, 9 pages, final version to appear in Phys.Lett.

    Particle streak velocity field measurements in a two-dimensional mixing layer

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    Using digital image processing of particle streak photography, the streamwise and perpendicular components of the velocity field were investigated, in the mid‐span plane of a two‐dimensional mixing layer, with a 6:1 velocity ratio. The Reynolds number of the flow, based on the local vorticity thickness and the velocity difference across the layer, ranged from 1360 to 2520, in the plane of observation. The significant result of this experiment was that the region of vorticity bearing fluid is confined to a small fraction of the flow. A second finding, consistent with the small regions of concentrated vorticity, was the observation of instantaneous streamwise velocity reversal, in the laboratory frame, in small regions of the flow
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