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In the late sixties the Canadian psychologist Laurence J. Peter advanced an apparently paradoxical principle, named since then after him, which can be summarized as follows: ‘Every new member in a hierarchical organization climbs the hierarchy until he/she reaches his/her level of maximum incompetence’. Despite its apparent unreasonableness, such a principle would realistically act in any organization where the mechanism of promotion rewards the best members and where the competence at their new level in the hierarchical structure does not depend on the competence they had at the previous level, usually because the tasks of the levels are very different to each other. Here we show, by means of agent based simulations, that if the latter two features actually hold in a given model of an organization with a hierarchical structure, then not only is the Peter principle unavoidable, but also it yields in turn a significant reduction of the global efficiency of the organization. Within a game theory-like approach, we explore different promotion strategies and we find, counterintuitively, that in order to avoid such an effect the best ways for improving the efficiency of a given organization are either to promote each time an agent at random or to promote randomly the best and the worst members in terms of competence. 相似文献
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A Clifford algebraic construction is shown to yield a simple generalization to any dimension of the Kustaanheimo-Stiefel regularization for the Kepler problem. 相似文献
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It has been proposed to rise Venice by injecting CO2 into an aquifer lying 600–800 m below its lagoon. It is shown that because of the prevailing ambient conditions in the aquifer phase change of CO2 cannot be avoided. The ensuing change of specific volume and compressibility will inhibit a uniform uplift pattern which is needed to avoid cracks in historical buildings. Further, both liquid and gaseous CO2 produce capillary effects at the contact surface with water in the voids of the reservoir rock and this affects its mechanical response. Hence further non homogeneity in the uplift pattern will be produced. This prevents the use of CO2 in the proposed conditions. 相似文献
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Simone Zanella Dr. Michele Mingozzi Alberto Dal Corso Dr. Roberto Fanelli Dr. Daniela Arosio Prof. Dr. Marco Cosentino Dr. Laura Schembri Dr. Franca Marino Dr. Marta De Zotti Prof. Dr. Fernando Formaggio Dr. Luca Pignataro Prof. Dr. Laura Belvisi Prof. Dr. Umberto Piarulli Prof. Dr. Cesare Gennari 《ChemistryOpen》2015,4(5):633-641
A dual-action ligand targeting both integrin αVβ3 and vascular endothelial growth factor receptors (VEGFRs), was synthesized via conjugation of a cyclic peptidomimetic αVβ3 Arg-Gly-Asp (RGD) ligand with a decapentapeptide. The latter was obtained from a known VEGFR antagonist by acetylation at the Lys13 side chain. Functionalization of the precursor ligands was carried out in solution and in the solid phase, affording two fragments: an alkyne VEGFR ligand and the azide integrin αVβ3 ligand, which were conjugated by click chemistry. Circular dichroism studies confirmed that both the RGD and VEGFR ligand portions of the dual-action compound substantially adopt the biologically active conformation. In vitro binding assays on isolated integrin αVβ3 and VEGFR-1 showed that the dual-action conjugate retains a good level of affinity for both its target receptors, although with one order of magnitude (10/20 times) decrease in potency. The dual-action ligand strongly inhibited the VEGF-induced morphogenesis in Human Umbilical Vein Endothelial Cells (HUVECs). Remarkably, its efficiency in preventing the formation of new blood vessels was similar to that of the original individual ligands, despite the worse affinity towards integrin αVβ3 and VEGFR-1. 相似文献
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D. Schürmann A. Di Leva L. Gialanella D. Rogalla F. Strieder N. De Cesare A. D'Onofrio G. Imbriani R. Kunz C. Lubritto A. Ordine V. Roca C. Rolfs M. Romano F. Schümann F. Terrasi H. -P. Trautvetter 《The European Physical Journal A - Hadrons and Nuclei》2005,26(2):301-305
The total cross-section of 12C(α,γ)16O was measured for the first time by a direct and ungated detection of the 16O recoils. This measurement in inverse kinematics using the recoil mass separator ERNA in combination with a windowless He
gas target allowed to collect data with high precision in the energy range E = 1.9 to 4.9 MeV. The data represent new information for the determination of the astrophysical S(E) factor. 相似文献
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