Imaging ancient and mummified specimens: dual-energy CT with effective atomic number imaging of two ancient Egyptian cat mummies

In mummified animals and humans, soft tissues like skin and muscle become more dense over time due to dehydration. At the same time, bone becomes less dense as marrow is replaced by air. This is a problem for the radiological examination of ancient specimens, as currently used methods such as single-energy CT and MRI rely on density and water content to produce tissue contrast in an image. Dual energy CT with effective atomic number imaging overcomes this problem, as the elemental constituents and consequently effective atomic number of a specimen remain relatively constant over time. This case study of two ancient Egyptian cat mummies demonstrates that effective atomic number imaging can differentiate desiccated soft tissues from low-density bone in ancient remains. Effective atomic number imaging has the potential for superior tissue contrast resolution when compared to single energy CT and can be used to provide new paleoradiological perspectives.James M. Bewes, Antony Morphett, F. Donald Pate, Maciej Henneberg, Andrew J. Low, Lars Kruse, Barry Craig, Aphrodite Hindson, Eleanor Adam

Assessing dose rate distributions in VMAT plans

Dose rate is an essential factor in radiobiology. As modern radiotherapy delivery techniques such as volumetric modulated arc therapy (VMAT) introduce dynamic modulation of the dose rate, it is important to assess the changes in dose rate. Both the rate of monitor units per minute (MU rate) and collimation are varied over the course of a fraction, leading to different dose rates in every voxel of the calculation volume at any point in time during dose delivery. Given the radiotherapy plan and machine specific limitations, a VMAT treatment plan can be split into arc sectors between Digital Imaging and Communications in Medicine control points (CPs) of constant and known MU rate. By calculating dose distributions in each of these arc sectors independently and multiplying them with the MU rate, the dose rate in every single voxel at every time point during the fraction can be calculated. Independently calculated and then summed dose distributions per arc sector were compared to the whole arc dose calculation for validation. Dose measurements and video analysis were performed to validate the calculated datasets. A clinical head and neck, cranial and liver case were analyzed using the tool developed. Measurement validation of synthetic test cases showed linac agreement to precalculated arc sector times within ±0.4 s and doses ±0.1 MU (one standard deviation). Two methods for the visualization of dose rate datasets were developed: the first method plots a two-dimensional (2D) histogram of the number of voxels receiving a given dose rate over the course of the arc treatment delivery. In similarity to treatment planning system display of dose, the second method displays the dose rate as color wash on top of the corresponding computed tomography image, allowing the user to scroll through the variation over time. Examining clinical cases showed dose rates spread over a continuous spectrum, with mean dose rates hardly exceeding 100 cGy min(-1) for conventional fractionation. A tool to analyze dose rate distributions in VMAT plans with sub-second accuracy was successfully developed and validated. Dose rates encountered in clinical VMAT test cases show a continuous spectrum with a mean less than or near 100 cGy min(-1) for conventional fractionation

Georg Lukács as a Communications Scholar: Cultural and Digital Labour in the Context of Lukács’ Ontology of Social Being

The task of this work is to apply thoughts from Georg Lukács’ final book, the Ontology of Social Being, for the theoretical analysis of cultural and digital labour. It discusses Lukács’ concepts of work and communication and relates them to the analysis of cultural and digital work. It also analyses his conception of the relation of labour and ideology and points out how we can make use of it for critically understanding social media ideologies. Lukács opposes the dualist separation of the realms of work and ideas. He introduces in this context the notion of teleological positing that allows us to better understand cultural and digital labour as well as associated ideologies, such as the engaging/connecting/sharing-ideology, today. The analysis shows that Lukács’ Ontology is in the age of Facebook, YouTube, and Twitter still a very relevant book, although it has thus far not received the attention that it deserves. This article also introduces the Ontology’s main ideas on work and culture, which is important because large parts of the book have not been translated from the German original into English. Lukács’ notion of teleological positing is crucial for understanding the common features of the economy and culture

Automated Counting of Bacterial Colony Forming Units on Agar Plates

Manual counting of bacterial colony forming units (CFUs) on agar plates is laborious and error-prone. We therefore implemented a colony counting system with a novel segmentation algorithm to discriminate bacterial colonies from blood and other agar plates

Reflexivity or orientation? Collective memories in the Australian, Canadian and New Zealand national press

With regard to the notion of ‘national reflexivity’, an important part of Beck’s cosmopolitan outlook, this article examines how, and, in what ways, collective memories of empire were reflexively used in Australian, Canadian and New Zealand national newspaper coverage of the 2012 Diamond Jubilee and London Olympic Games. In contrast to Beck, it is argued that examples of national reflexivity were closely tied to the history of the nation-state, with collective memories of the former British Empire used to debate, critique and appraise ‘the nation’. These memories were discursively used to ‘orientate’ each nation’s postcolonial emergence, suggesting that examples of national reflexivity, within the press’ coverage, remained closely tied to the ‘historical fetishes’ enveloped in each nations’ imperial past(s). This implies that the ‘national outlook’ does not objectively overlook, uncritically absorb or reflexively acknowledge differences with ‘the other’, but instead, negotiates a historically grounded and selective appraisal of the past that reveals a contingent and, at times, ambivalent, interplay with ‘the global’

Critical discourse studies: Where to from here?

This paper surveys critical discourse studies to the present and claims that, to avoid lapsing into comfortable orthodoxy in its mature phase, CDS needs to reassert its transformative radical teleology. The initial part of the paper reasserts the need for a strong social theory given the materialist and context-bound nature of discourse in daily activity. From this basis, the paper then characterizes the “new times” in which contemporary discourse occurs, and briefly surveys those issues typically analyzed, namely political economy, race and gender, and critical literacy. By considering people's ordinary lives, the paper then suggests that subject and agency, and calculative technologies of management deserve, and new modalities need, more research. Transdisciplinarity is encouraged, particularly with social psychology and critical management studies

Train speed estimations from ground vibration measurements using a simple rail deflection model mask

The speed of passing trains is conventionally estimated using Doppler speed guns, or optical sensors. However in many cases, these techniques are not applicable when the measured trains are not visible (for example in tunnels) or close access to the track is not possible. An alternative method to estimate train speed from ground vibration measurements is presented in this paper. The method takes advantage of the relation between vibration levels and the cyclic repetition of the excitation forces created by the wheels. A train mask, expressed in the wavelength domain, is derived from a simple rail deflection model induced by the train wheels. The vibration spectrum at very low frequency and the train mask are qualitatively compared to match the various peaks. Vibration and train speed measurements have been undertaken near St Denys station, Southampton. Very good agreements have been observed between the direct train speed measurements and the proposed estimation method.</p