Conceptualising the PhD as preparing for academic practice in geography

© 2014, Springer Science+Business Media Dordrecht. This paper situates the geography PhD within the broader context of doctoral education. It addresses questions relating to the PhD as preparation for future academic work. Theoretical and practical ideas are woven through a discussion of the work of the Centre for Excellence in Preparing for Academic Practice, at the University of Oxford, UK. The Centre initiated wide-ranging reforms and has had lasting impacts, with a philosophy of remaining sensitive to disciplinary context. The paper argues that cultural historical activity theory is a useful lens for understanding challenges in contemporary doctoral education, and responses to them. Key concepts are outlined, and a worked example provided, drawing from the Centre’s work. Connections are made with relevant initiatives specific to geography

Galaxy pairs in the Sloan Digital Sky Survey - IX: Merger-induced AGN activity as traced by the Wide-field Infrared Survey Explorer

Interactions between galaxies are predicted to cause gas inflows that can potentially trigger nuclear activity. Since the inflowing material can obscure the central regions of interacting galaxies, a potential limitation of previous optical studies is that obscured Active Galactic Nuclei (AGNs) can be missed at various stages along the merger sequence. We present the first large mid-infrared study of AGNs in mergers and galaxy pairs, in order to quantify the incidence of obscured AGNs triggered by interactions. The sample consists of galaxy pairs and post-mergers drawn from the Sloan Digital Sky Survey that are matched to detections by the Wide Field Infrared Sky Explorer (WISE). We find that the fraction of AGN in the pairs, relative to a mass-, redshift- and environment-matched control sample, increases as a function of decreasing projected separation. This enhancement is most dramatic in the post-merger sample, where we find a factor of 10-20 excess in the AGN fraction compared with the control. Although this trend is in qualitative agreement with results based on optical AGN selection, the mid-infrared selected AGN excess increases much more dramatically in the post-mergers than is seen for optical AGN. Our results suggest that energetically dominant optically obscured AGNs become more prevalent in the most advanced mergers, consistent with theoretical predictions.Comment: 8 pages, 7 figures accepted to MNRAS (with minor revisions

The Stripe 82 1-2 GHz Very Large Array Snapshot Survey: Multiwavelength Counterparts

We have combined spectrosopic and photometric data from the Sloan Digital Sky Survey (SDSS) with $1.4$ GHz radio observations, conducted as part of the Stripe 82 $1-2$ GHz Snapshot Survey using the Karl G. Jansky Very Large Array (VLA), which covers $\sim100$ sq degrees, to a flux limit of 88 $\mu$Jy rms. Cross-matching the $11\,768$ radio source components with optical data via visual inspection results in a final sample of $4\,795$ cross-matched objects, of which $1\,996$ have spectroscopic redshifts and $2\,799$ objects have photometric redshifts. Three previously undiscovered Giant Radio Galaxies (GRGs) were found during the cross-matching process, which would have been missed using automated techniques. For the objects with spectroscopy we separate radio-loud Active Galactic Nuclei (AGN) and star-forming galaxies (SFGs) using three diagnostics and then further divide our radio-loud AGN into the HERG and LERG populations. A control matched sample of HERGs and LERGs, matched on stellar mass, redshift and radio luminosity, reveals that the host galaxies of LERGs are redder and more concentrated than HERGs. By combining with near-infrared data, we demonstrate that LERGs also follow a tight $K-z$ relationship. These results imply the LERG population are hosted by population of massive, passively evolving early-type galaxies. We go on to show that HERGs, LERGs, QSOs and star-forming galaxies in our sample all reside in different regions of a WISE colour-colour diagram. This cross-matched sample bridges the gap between previous `wide but shallow' and `deep but narrow' samples and will be useful for a number of future investigations.Comment: 17 pages, 19 figures. Resubmitted to MNRAS after the initial comment

Computer-aided liner optimization for broadband noise

In this article the attenuation of broadband noise in an acoustically-lined circular-section duct is investigated. The aim is to predict how an axially segmented liner influences the attenuation of broadband noise in an aero-engine intake. The sound field is modelled using a multi-modal representation, assuming an ensemble of uncorrelated modes over a wide range of frequencies. An optimization procedure based on a Response Surface Model is used to investigate the optimum uniform and axially-segmented acoustic liner that maximizes the attenuation of broadband noise. An approximate calculation of the Perceived Noise level (PNL) is used for the objective function. In this article the benefit of using an axially segmented liner instead of a uniform liner to attenuate broadband noise is demonstrated

Rapid, multiplexed microfluidic phage display

The development of a method for high-throughput, automated proteomic screening could impact areas ranging from fundamental molecular interactions to the discovery of novel disease markers and therapeutic targets. Surface display techniques allow for efficient handling of large molecular libraries in small volumes. In particular, phage display has emerged as a powerful technology for selecting peptides and proteins with enhanced, target-specific binding affinities. Yet, the process becomes cumbersome and time-consuming when multiple targets are involved.Here we demonstrate for the first time a microfluidic chip capable of identifying high affinity phage displayed peptides for multiple targets in just a single round and without the need for bacterial infection. The chip is shown to be able to yield well-established control consensus sequences while simultaneously identifying new sequences for clinically important targets. Indeed, the confined parameters of the device allow not only for highly controlled assay conditions but also introduce a significant time-reduction to the phage display process. We anticipate that this easily-fabricated, disposable device has the potential to impact areas ranging from fundamental studies of protein, peptide, and molecular interactions, to applications such as fully automated proteomic screening

Leading from a Distance: Advancements in Virtual Leadership Research

Although leadership has long been recognized as critical in virtual environments, observers have noted that a surprisingly small number of studies have focused on virtual leadership. In the current chapter we examine what we currently know about virtual leadership and identify promising future research directions. We begin by examining changes in the leadership context, most notably advances in technology and the growing adoption of virtual work arrangements. We then trace the evolution of the research that has examined virtual leadership at both the dyadic and team levels, highlighting key conceptual and empirical advances. Finally, we conclude the chapter by discussing future research directions that have the potential to make important contributions to both theory and practice in the area of virtual leadership

Records of Melanistic American Red Squirrels (Tamiasciurus hudsonicus) from Nova Scotia

Though melanism has been observed in several species of North American sciurids, the occurrence of this phenotype is relatively rare in American Red Squirrels (Tamiasciurus hudsonicus). We provide the first detailed accounts of melanistic Red Squirrels observed in Nova Scotia, Canada

CONCEPTUALISING THE PHD AS PREPARING FOR ACADEMIC PRACTICE IN GEOGRAPHY

Abstract This paper situates the geography PhD within the broader context of doctoral education. It addresses questions relating to the PhD as preparation for future academic work. Theoretical and practical ideas are woven through a discussion of the work of the Centre for Excellence in Preparing for Academic Practice, at the University of Oxford (UK). The Centre initiated wide-ranging reforms and has had lasting impacts, with a philosophy of remaining sensitive to disciplinary context. The paper argues that Cultural Historical Activity Theory (CHAT) is a useful lens for understanding challenges in contemporary doctoral education, and responses to them. Key concepts are outlined, and a worked example provided, drawing from the Centre's work. Connections are made with relevant initiatives specific to geography

Phosphoinositide Modulation of Heteromeric Kv1 Channels Adjusts Output of Spiral Ganglion Neurons from Hearing Mice

Spiral ganglion neurons (SGNs) relay acoustic code from cochlear hair cells to the brainstem, and their stimulation enables electrical hearing via cochlear implants. Rapid adaptation, a mechanism that preserves temporal precision, and a prominent feature of auditory neurons, is regulated via dendrotoxin-sensitive low-threshold voltage-activated (LVA) K(+) channels. Here, we investigated the molecular physiology of LVA currents in SGNs cultured from mice following the onset of hearing (postnatal days 12-21). Kv1.1- and Kv1.2-specific toxins blocked the LVA currents in a comparable manner, suggesting that both subunits contribute to functional heteromeric channels. Confocal immunofluorescence in fixed cochlear sections localized both Kv1.1 and Kv1.2 subunits to specific neuronal microdomains, including the somatic membrane, juxtaparanodes, and the first heminode, which forms the spike initiation site of the auditory nerve. The spatial distribution of Kv1 immunofluorescence appeared mutually exclusive to that of Kv3.1b subunits, which mediate high-threshold voltage-activated currents. As Kv1.2-containing channels are positively modulated by membrane phosphoinositides, we investigated the influence of phosphatidylinositol-4,5-bisphosphate (PIP2) availability on SGN electrophysiology. Reducing PIP2 production using wortmannin, or sequestration of PIP2 using a palmitoylated peptide (PIP2-PP), slowed adaptation rate in SGN populations. PIP2-PP specifically inhibited the LVA current in SGNs, an effect reduced by intracellular dialysis of a nonhydrolysable analog of PIP2. PIP2-PP also inhibited heterologously expressed Kv1.1/Kv1.2 channels, recapitulating its effect in SGNs. Collectively, the data identify Kv1.1/Kv1.2 heteromeric channels as key regulators of action potential initiation and propagation in the auditory nerve, and suggest that modulation of these channels by endogenous phosphoinositides provides local control of membrane excitability