1,188 research outputs found

    Leading Virtual Teams.

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    Virtual teams, whose members are geographically dispersed and cross-functional yet work on highly interdependent tasks, present unique leadership challenges. Based on our observations, interviews,..

    Pharmacological strategies to reduce anthracycline-associated cardiotoxicity in cancer patients.

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    INTRODUCTION: Anthracycline chemotherapeutic agents are widely used in the treatment of hematological and solid tumors, working principally through DNA intercalation and topoisomerase II inhibition. However, they are also well known to have cardiotoxic sequelae, commonly denoted as a reduction in ejection fraction. Drug-associated cardiotoxicity remains a significant limiting factor in the use of anthracyclines. AREAS COVERED: In this review, we explore the potential mechanisms of anthracycline-associated cardiotoxicity, identifying high-risk cohorts and approaches to cardiovascular monitoring. The mechanisms through which cardiotoxicity occurs are complex and diverse, ultimately leading to increased oxidative stress, mitochondrial dysfunction, and subsequent cellular apoptosis. Many of the cardiotoxic effects of anthracyclines exhibit a dose-dependent cumulative relationship and are more apparent in patients with previously existing cardiovascular risk factors. Long-term cardiovascular monitoring and optimization of risk factors, prior to commencing treatment as well as beyond the time of treatment, is therefore essential. EXPERT OPINION: We discuss some of the pharmacological strategies proposed to mitigate anthracycline-associated cardiotoxicity as well as prevention strategies to reduce the burden of coexisting cardiovascular risk factors. We highlight methods of early detection of patient cohorts who are at increased risk of developing anthracycline-associated cardiotoxicity and identify potential avenues for further research

    Phase Transitions of Charged Scalars at Finite Temperature and Chemical Potential

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    We calculate the grand canonical partition function at the one-loop level for scalar quantum electrodynamics at finite temperature and chemical potential. A classical background charge density with a charge opposite that of the scalars ensures the neutrality of the system. For low density systems we find evidence of a first order phase transition. We find upper and lower bounds on the transition temperature below which the charged scalars form a condensate. A first order phase transition may have consequences for helium-core white dwarf stars in which it has been argued that such a condensate of charged helium-4 nuclei could exist.Comment: 20 pages, 3 figures. Version accepted for publication in JHE

    THE IMPACT OF TEAM EMPOWERMENT ON VIRTUAL TEAM PERFORMANCE: THE MODERATING ROLE OF FACE-TO-FACE INTERACTION.

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    We investigated the relationship between team empowerment and virtual team performance and the moderating role of the extent of face-to-face interaction using 35 sales and service virtual teams in a high-technology organization. Team empowerment was positively related to two independent assessments of virtual team performance--process improvement and customer satisfaction. Further, the number of face-to-face meetings moderated the relationship between team empowerment and process improvement: team empowerment was a stronger predictor for teams that met face-to-face less, rather than more, frequently

    A multilevel study of leadership, empowerment, and performance in teams.

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    A multilevel model of leadership, empowerment, and performance was tested using a sample of 62 teams, 445 individual members, 62 team leaders, and 31 external managers from 31 stores of a Fortune 500 company. Leader-member exchange and leadership climate related differently to individual and team empowerment and interacted to influence individual empowerment. Also, several relationships were supported in more but not in less interdependent teams. Specifically, leader-member exchange related to individual performance partially through individual empowerment; leadership climate related to team performance partially through team empowerment; team empowerment moderated the relationship between individual empowerment and performance; and individual performance was positively related to team performance. Contributions to team leadership theory, research, and practices are discussed. Keywords: teams, leadership, motivation, multilevel, performance As a result of the widespread move to team-based organizations in industry, managers are often asked to lead and motivate not only individuals but also teams as a whole Perhaps owing to these same trends in industry, researchers have primarily focused their efforts at the team level of analysis without considering important individual-level processes in team contexts Accordingly, the main purpose of our study was to extend previous research and answer these theoretically and practically relevant calls for multilevel team leadership and motivation research. We do so by examining team leader behaviors and employee motivation simultaneously at both the individual and team levels of analysis. In particular, we develop and test a multilevel model of leadership and motivation through the lens of employee empowerment, a motivational concept that, over the last two de

    Spatially extended K I 7699 emission in the nebula of VY CMa: Kinematics and geometry

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    Long-slit echelle spectra reveal bright extended emission from the K I lambda7699 resonance line in the reflection nebula surrounding the extreme red supergiant VY Canis Majoris. The central star has long been known for its unusually-bright K I emission lines, but this is the first report of intrinsic emission from K I in the nebula. The extended emission is not just a reflected spectrum of the star, but is due to resonant scattering by K atoms in the outer nebula itself, and is therefore a valuable probe of the kinematics and geometry of VY CMa's circumstellar environment. Dramatic velocity structure is seen in the long-slit spectra, and most lines of sight intersect multiple distinct velocity components. A faint ``halo'' at large distances from the star does appear to show a reflected spectrum, however, and suggests a systemic velocity of +40 km/s with respect to the Sun. The most striking feature is blueshifted emission from the filled interior of a large shell seen in images; the kinematic structure is reminiscent of a Hubble flow, and provides strong evidence for asymmetric and episodic mass loss due to localized eruptions on the star's surface.Comment: 5 pages, 3 figures. Accepted MNRAS. Updated version with minor change

    Thermodynamics of Non-Topological Solitons

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    In theories with low energy supersymmetry breaking, the effective potential for squarks and sleptons has generically nearly flat directions, V(phi) ~ M^4 (log(phi/M))^n. This guarantees the existence of stable non-topological solitons, Q-balls, that carry large baryon number, B >> (M/m_p)^4, where m_p is the proton mass. We study the behaviour of these objects in a high temperature plasma. We show that in an infinitely extended system with a finite density of the baryon charge, the equilibrium state is not homogeneous and contains Q-balls at any temperature. In a system with a finite volume, Q-balls evaporate at a volume dependent temperature. In the cosmological context, we formulate the conditions under which Q-balls, produced in the Early Universe, survive till the present time. Finally, we estimate the baryon to cold dark matter ratio in a cosmological scenario in which Q-balls are responsible for both the net baryon number of the Universe and its dark matter. We find out naturally the correct orders of magnitude for M ~ 1...10 TeV: \eta ~ 10^{-10} (M/TeV)^{-2} (B/10^{26})^{-1/2}.Comment: 31 pages, 5 figure

    Q-ball dynamics from atomic Bose-Einstein condensates

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    Relativistic scalar field theories with a conserved global charge Q possess often (meta)stable spherically symmetric soliton solutions, called Q-balls. We elaborate on the perfect formal analogy which exists between Q-balls, and spherically symmetric solitons in certain non-relativistic atomic Bose-Einstein condensates, for which the dominant interatomic interaction can be tuned attractive. In a harmonic trap, present in existing experiments, the Q-ball solution is modified in an essential way. If the trap is significantly prolongated in one direction, however, then genuine solitons do appear, and actual experimental data can be obtained for some of the Q-ball properties studied numerically in the relativistic cosmological context, such as their formation and collisions. We also suggest conditions under which the same cosmologically relevant analogies could be extended to the fully three-dimensional case.Comment: 16 pages. v2: clarifications and references adde
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