9,073 research outputs found

    Autopilot? A reflexive review of the piloting process in qualitative e-research

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    Purpose: This paper examines an oft-neglected aspect of qualitative research practice – conducting a pilot – using the innovative approach of ‘e-research’ to generate both practical and methodological insights. Approach: Using the authors’ ‘e-research’ pilot as a reflexive case study, key methodological issues are critically reviewed. This review is set in a broader context of the qualitative methods literature in which piloting appears largely as an implicit practice. Using a new and emerging approach (‘e-research’) provides a prompt to review our ‘autopilot’ tendencies and offers a new lens for analysing research practice. Findings: We find that despite an initial focus on ‘practical’ aspects of data collection within our ‘e-research’, the pilot opened up a range of areas for further consideration. We review research ethics, collaborative research practices and data management issues specifically for e-research but also reflect more broadly on potential implications for piloting within other research designs. Practical implications: We aim to offer both practical and methodological insights for qualitative researchers, whatever their methodological orientation, so that they might develop approaches for piloting that are appropriate to their own research endeavours. More specifically, we offer tentative guidance to those venturing into the emerging area of ‘e-research’. Value: This paper offers insight into an oft-ignored aspect of qualitative research, whilst also engaging in emerging area of methodological interest

    Is space really expanding? A counterexample

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    In all Friedman models, the cosmological redshift is widely interpreted as a consequence of the general-relativistic phenomenon of EXPANSION OF SPACE. Other commonly believed consequences of this phenomenon are superluminal recession velocities of distant galaxies and the distance to the particle horizon greater than c*t (where t is the age of the Universe), in apparent conflict with special relativity. Here, we study a particular Friedman model: empty universe. This model exhibits both cosmological redshift, superluminal velocities and infinite distance to the horizon. However, we show that the cosmological redshift is there simply a relativistic Doppler shift. Moreover, apparently superluminal velocities and `acausal' distance to the horizon are in fact a direct consequence of special-relativistic phenomenon of time dilation, as well as of the adopted definition of distance in cosmology. There is no conflict with special relativity, whatsoever. In particular, INERTIAL recession velocities are subluminal. Since in the real Universe, sufficiently distant galaxies recede with relativistic velocities, these special-relativistic effects must be at least partly responsible for the cosmological redshift and the aforementioned `superluminalities', commonly attributed to the expansion of space. Let us finish with a question resembling a Buddhism-Zen `koan': in an empty universe, what is expanding?Comment: 12 pages, no figures; added Appendix with a calculation of the cosmological redshift in `private space

    A Near Horizon CFT Dual for Kerr-Newman-AdSAdS

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    We show that the near horizon regime of a Kerr-Newman-AdSAdS (KNAdSAdS) black hole, given by its two dimensional analogue alaa la Robinson and Wilczek (2005 Phys. Rev. Lett. 95 011303), is asymptotically AdS2AdS_2 and dual to a one dimensional quantum conformal field theory (CFT). The s-wave contribution of the resulting CFT's energy-momentum-tensor together with the asymptotic symmetries, generate a centrally extended Virasoro algebra, whose central charge reproduces the Bekenstein-Hawking entropy via Cardy's Formula. Our derived central charge also agrees with the near extremal Kerr/CFT Correspondence (2009 Phys. Rev. D 80, 124008) in the appropriate limits. We also compute the Hawking temperature of the KNAdSAdS black hole by coupling its Robinson and Wilczek two dimensional analogue (RW2DA) to conformal matter.Comment: 15 pages. Major edits and revisions. Final version accepted for publication in IJMP

    A selective transformation of enals into chiral γ-amino alcohols.

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    A one-pot synthesis of chiral amino alcohols from α,β-unsaturated aldehydes is reported which circumvents competitive 1,2- versus 1,4-boryl addition, by means of using a sterically hindered amine-derived imine. In addition to the complete chemoselectivity, modification of the Cu(I) catalyst with readily available chiral diphosphines, such as (R)-DM-BINAP, gave the 1,4-boryl addition products with high levels of asymmetric induction

    Universality of Load Balancing Schemes on Diffusion Scale

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    We consider a system of NN parallel queues with identical exponential service rates and a single dispatcher where tasks arrive as a Poisson process. When a task arrives, the dispatcher always assigns it to an idle server, if there is any, and to a server with the shortest queue among dd randomly selected servers otherwise (1dN)(1 \leq d \leq N). This load balancing scheme subsumes the so-called Join-the-Idle Queue (JIQ) policy (d=1)(d = 1) and the celebrated Join-the-Shortest Queue (JSQ) policy (d=N)(d = N) as two crucial special cases. We develop a stochastic coupling construction to obtain the diffusion limit of the queue process in the Halfin-Whitt heavy-traffic regime, and establish that it does not depend on the value of dd, implying that assigning tasks to idle servers is sufficient for diffusion level optimality
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