3,736 research outputs found

    The Perils of Positivity

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    The passion and productivity that characterizes research on positive organizational behavior (POB) is impressive. Yet POB research is accumulating so rapidly that it may exceed what the field's conceptual, methodological, and ideological foundation can bear. I discuss here six concerns prompted by the articles in this special issue. These concerns are (1) the emphasis of positive organizational scholarship on individual-level phenomena, (12) the ahistorical character of POB research and writing, (3) the construct validity of key concepts, (4) over-reliance on a particular research strategy, (5) implicit acceptance of fundamental flaws in how work and organizations are designed, and (6) the seductiveness of new research paradigms.Psycholog

    Magnetic field topology of the RS CVn star II Pegasi

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    The dynamo processes in cool active stars generate complex magnetic fields responsible for prominent surface stellar activity and variability at different time scales. For a small number of cool stars magnetic field topologies were reconstructed from the time series of spectropolarimetric observations using the Zeeman Doppler imaging (ZDI) method. In this study we follow a long-term evolution of the magnetic field topology of the RS CVn binary star II Peg. We collected high-resolution circular polarisation observations of II Peg using the SOFIN spectropolarimeter at the Nordic Optical Telescope. These data cover 12 epochs spread over 7 years. A multi-line diagnostic technique in combination with a new ZDI code is applied to interpret these observations. Magnetic inversions using these data reveals evolving magnetic fields with typical local strengths of 0.5-1.0 kG and complex topologies. Despite using a self-consistent magnetic and temperature mapping technique, we do not find a clear correlation between magnetic and temperature features in the ZDI maps. Neither do we confirm the presence of persistent azimuthal field rings found in other RS CVn stars. Reconstruction of the magnetic field topology of II Peg reveals significant evolution of both the surface magnetic field structure and the extended magnetospheric field geometry. From 2004 to 2010 the total field energy drastically declined and the field became less axisymmetric. This also coincided with the transition from predominantly poloidal to mainly toroidal field topology. A qualitative comparison of the ZDI maps of II Peg with the prediction of dynamo theory suggests that the magnetic field in this star is produced mainly by the turbulent alpha^2 dynamo rather than the solar alphaOmega dynamo. Our results do not show a clear active longitude system, nor is there an evidence of the presence of an azimuthal dynamo wave.Comment: 20 pages, 10 figures; accepted for publication in Astronomy & Astrophysic

    Rethinking Leadership, or Team LEaders Are Not Music Directors

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    Let us begin with a thought experiment. Think for a moment about one of the finest groups you have every seen—one that accomplished its work superbly, that got better and better as a performing unit over time, and whose members came away from the group experience wiser and more skilled than they were before. Next, think about a different group, one that failed to achieve its purposes, that deteriorated in performance capability over time, and whose members found the group experience far more frustrating than fulfilling

    Letter to RJM from Larry J. Hackman

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    Letter to RJM from Larry J. Hackman

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    Spot activity of the RS CVn star {\sigma} Geminorum

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    We model the photometry of RS CVn star σ\sigma Geminorum to obtain new information on the changes of the surface starspot distribution, i.e., activity cycles, differential rotation and active longitudes. We use the previously published Continuous Periods Search-method (CPS) to analyse V-band differential photometry obtained between the years 1987 and 2010 with the T3 0.4 m Automated Telescope at the Fairborn Observatory. The CPS-method divides data into short subsets and then models the light curves with Fourier-models of variable orders and provides estimates of the mean magnitude, amplitude, period and light curve minima. These light curve parameters are then analysed for signs of activity cycles, differential rotation and active longitudes. We confirm the presence of two previously found stable active longitudes, synchronised with the orbital period Porb=19.60P_{\rm{orb}}=19.60d and find eight events where the active longitudes are disrupted. The epochs of the primary light curve minima rotate with a shorter period Pmin,1=19.47P_{\rm{min,1}}=19.47d than the orbital motion. If the variations in the photometric rotation period were to be caused by differential rotation, this would give a differential rotation coefficient of α≄0.103\alpha \ge 0.103. The presence of two slightly different periods of active regions may indicate a superposition of two dynamo modes, one stationary in the orbital frame and the other one propagating in the azimuthal direction. Our estimate of the differential rotation is much higher than previous results. However, simulations show that this can be caused by insufficient sampling in our data.Comment: 10 pages, 6 figures. Submitted to A&
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