489 research outputs found

    Coarsening of Two Dimensional Foam on a Dome

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    In this paper we report on bubble growth rates and on the statistics of bubble topology for the coarsening of a dry foam contained in the narrow gap between two hemispheres. By contrast with coarsening in flat space, where six-sided bubbles neither grow nor shrink, we observe that six sided bubbles grow with time at a rate that depends on their size. This result agrees with the modification to von Neumann's law predicted by J.E. Avron and D. Levine. For bubbles with a different number of sides, except possibly seven, there is too much noise in the growth rate data to demonstrate a difference with coarsening in flat space. In terms of the statistics of bubble topology, we find fewer 3, 4, and 5 sided bubbles, and more 6 and greater sided bubbles, in comparison with the stationary distribution for coarsening in flat space. We also find good general agreement with the Aboav-Weaire law for the average number of sides of the neighbors of an n-sided bubble

    Pharmacological inhibition of RAS overcomes FLT3 inhibitor resistance in FLT3-ITD+ AML through AP-1 and RUNX1

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    \ua9 2024 The Author(s). AML is characterized by mutations in genes associated with growth regulation such as internal tandem duplications (ITD) in the receptor kinase FLT3. Inhibitors targeting FLT3 (FLT3i) are being used to treat patients with FLT3-ITD+ but most relapse and become resistant. To elucidate the resistance mechanism, we compared the gene regulatory networks (GRNs) of leukemic cells from patients before and after relapse, which revealed that the GRNs of drug-responsive patients were altered by rewiring their AP-1-RUNX1 axis. Moreover, FLT3i induces the upregulation of signaling genes, and we show that multiple cytokines, including interleukin-3 (IL-3), can overcome FLT3 inhibition and send cells back into cycle. FLT3i leads to loss of AP-1 and RUNX1 chromatin binding, which is counteracted by IL-3. However, cytokine-mediated drug resistance can be overcome by a pan-RAS inhibitor. We show that cytokines instruct AML growth via the transcriptional regulators AP-1 and RUNX1 and that pan-RAS drugs bypass this barrier

    From sleep spindles of natural sleep to spike and wave discharges of typical absence seizures: is the hypothesis still valid?

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    The temporal coincidence of sleep spindles and spike-and-wave discharges (SWDs) in patients with idiopathic generalized epilepsies, together with the transformation of spindles into SWDs following intramuscular injection of the weak GABAA receptor (GABAAR) antagonist, penicillin, in an experimental model, brought about the view that SWDs may represent ‘perverted’ sleep spindles. Over the last 20 years, this hypothesis has received considerable support, in particular by in vitro studies of thalamic oscillations following pharmacological/genetic manipulations of GABAARs. However, from a critical appraisal of the evidence in absence epilepsy patients and well-established models of absence epilepsy it emerges that SWDs can occur as frequently during wakefulness as during sleep, with their preferential occurrence in either one of these behavioural states often being patient dependent. Moreover, whereas the EEG expression of both SWDs and sleep spindles requires the integrity of the entire cortico-thalamo-cortical network, SWDs initiates in cortex while sleep spindles in thalamus. Furthermore, the hypothesis of a reduction in GABAAR function across the entire cortico-thalamo-cortical network as the basis for the transformation of sleep spindles into SWDs is no longer tenable. In fact, while a decreased GABAAR function may be present in some cortical layers and in the reticular thalamic nucleus, both phasic and tonic GABAAR inhibitions of thalamo-cortical neurons are either unchanged or increased in this epileptic phenotype. In summary, these differences between SWDs and sleep spindles question the view that the EEG hallmark of absence seizures results from a transformation of this EEG oscillation of natural sleep

    Powers of Romance: The Liminal Challenges of Managing Organizational Intimacy

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    © The Author(s) 2014 Problematic organizational relationships have recently been at the core of highly visible media coverage. Most analyses of sexual relations in organizations have been, however, simplistic and unidimensional, and have placed insufficient systematic emphasis on the role of governmentality in the social construction of organizational romance. In this article, we proceed in two theoretical steps. First, we elaborate a typology of organizational romance that covers different manifestations of this nuanced process. We think of these as organizational strategies of governmentality. Second, we elaborate and identify liminal cases that fall into the interstices of the four predominant ways of managing sexual relationships in organizations. We think of these as vases of liquid love and life that evade the border controls of regulation by governmentality. Finally, we relate these issues to debates about the nature of the civilizational process and suggest hypotheses for future research

    Management Ideologies and Organizational Spirituality: a Typology

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    The topic of spirituality is gaining an increasing visibility in organization studies. It is our contention that every theory of organization is a theory of organizational spirituality. Based on Barley and Kunda’s 1992 Administrative Science Quarterly article, we discuss the evolution of management theories as spirituality theories. From such analysis, we suggest that there may be both a meaningful/liberating and an instrumental/exploitative side in the relationship between organizations and spirituality. Such a possibility is illustrated with a typology that advances four possible types of organizations regarding spirituality: the soulful organization, the holistic organization, the ascetic organization, and the professional organization. The expression of spirituality in each of these forms is discussed with the aim of contributing to a theoretically-based analysis of organizational spirituality.N/
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