Diffracting Digital Images in the Making

This paper presents a diffractive dialogue between prehistoric imagery, digital or computational imaging, and art practices. Our dialogue begins by responding to Thomas Nail’s recent argument that digital images force us to recognize the ontological mobility and instability of all images, whether contemporary or ancient (Nail 2019). In tandem with this, Back Danielsson and Jones (2020, 4) develop the notion of ‘Images in the making’. By discussing images as being ‘in-the-making’ they underline an understanding of images as conditions of possibility, and as processes of assembly, outlining the way in which images draw together and bringing into relation the cognitive and material components of the world. Although, the original notion of ‘images in the making’ drew on digital images to make its argument, it did not explore the special character of digital images in any detail. This paper develops the notion of images in the making in the context of the digital domain. It will focus on two digital imaging techniques developed within archaeology and cultural heritage– Reflectance Transformation Imaging (RTI) and Structure from Motion photogrammetry (SfM)- exploring how these techniques play out in heritage and art world contexts and practices. The paper will highlight digital images as unstable compositions, explore how digital images in the making enable us to reconsider the shifting temporal character of the image, and discuss the way in which the digital image forces us to disrupt the representational assumptions bound up in the relationship between the virtual and the actual; we argue that digital images are ‘phygital’ and are better understood as existing somewhere in the blurred ground between the physical and the digital (Dawson and Reilly 2019). We argue that the diffractive moment in these encounters between archaeology and art practice disclose the potential of digital imaging to recursively question the complex ontological composition of images and the ability of images to act and affect

Viking Mortuary Citations

Introducing the European Journal of Archaeology’s special issue ‘Mortuary Citations: Death and Memory in the Viking World’, this article outlines the justification and theoretical framework underpinning a new set of studies on Viking-age mortuary and commemorative practice as strategies of mortuary citation. The contributions to the collection are reviewed in relation to strengths and weaknesses in existing research and broader themes in mortuary archaeological research into memory work in past societies

On Field Theory Thermalization from Gravitational Collapse

Motivated by its field theory interpretation, we study gravitational collapse of a minimally coupled massless scalar field in Einstein gravity with a negative cosmological constant. After demonstrating the accuracy of the numerical algorithm for the questions we are interested in, we investigate various aspects of the apparent horizon formation. In particular, we study the time and radius of the apparent horizon formed as functions of the initial Gaussian profile for the scalar field. We comment on several aspects of the dual field theory picture.Comment: 31 pages, 17 figures; V2 Some figures corrected, minor revision. arXiv admin note: substantial text overlap with arXiv:1106.233

Citations in Stone: The Material World of Hogbacks

This is an Accepted Manuscript of an article published by Taylor & Francis in European Journal of Archaeology on 06/07/2016, available online: doi 10.1080/14619571.2016.1186910This is an Accepted Manuscript of an article published by Taylor & Francis in European Journal of Archaeology on 06/07/2016, available online: doi 10.1080/14619571.2016.1186910This article explores a meshwork of citations to other material cultures and architectures created by the form and ornament of house-shaped early medieval recumbent stone monuments popularly known in Britain as ‘hogbacks’. In addition to citing the form and ornament of contemporary buildings, shrines, and tombs, this article suggests recumbent mortuary monuments referenced a far broader range of contemporary portable artefacts and architectures. The approach takes attention away from identifying any single source of origin for hogbacks. Instead, considering multi-scalar and multi-media references within the form and ornament of different carved stones provides the basis for revisiting their inherent variability and their commemorative efficacy by creating the sense of an inhabited mortuary space in which the dead are in dialogue with the living. By alluding to an entangled material world spanning Norse and Insular, ecclesiastical and secular spheres, hogbacks were versatile technologies of mortuary remembrance in the Viking Age

Thermalization with a chemical potential from AdS spaces

The time-scale of thermalization in holographic dual models with a chemical potential in diverse number of dimensions is systematically investigated using the gauge/gravity duality. We consider a model with a thin-shell of charged dust collapsing from the boundary toward the bulk interior of asymptotically anti-de Sitter (AdS) spaces. In the outer region there is a Reissner-Nordstr\"om-AdS black hole (RNAdS-BH), while in the inner region there is an anti-de Sitter space. We consider renormalized geodesic lengths and minimal area surfaces as probes of thermalization, which in the dual quantum field theory (QFT) correspond to two-point functions and expectation values of Wilson loops, respectively. We show how the behavior of these extensive probes changes for charged black holes in comparison with Schwarzschild-AdS black holes (AdS-BH), for different values of the black hole mass and charge. The full range of values of the chemical potential over temperature ratio in the dual QFT is investigated. In all cases, the structure of the thermalization curves shares similar features with those obtained from the AdS-BH. On the other hand, there is an important difference in comparison with the AdS-BH: the thermalization times obtained from the renormalized geodesic lengths and the minimal area surfaces are larger for the RNAdS-BH, and they increase as the black hole charge increases.Comment: 32 pages, 4 figures, references added, appendix added, typos correcte

Jet size dependence of single jet suppression in lead-lead collisions at sqrt(s(NN)) = 2.76 TeV with the ATLAS detector at the LHC

Measurements of inclusive jet suppression in heavy ion collisions at the LHC provide direct sensitivity to the physics of jet quenching. In a sample of lead-lead collisions at sqrt(s) = 2.76 TeV corresponding to an integrated luminosity of approximately 7 inverse microbarns, ATLAS has measured jets with a calorimeter over the pseudorapidity interval |eta| < 2.1 and over the transverse momentum range 38 < pT < 210 GeV. Jets were reconstructed using the anti-kt algorithm with values for the distance parameter that determines the nominal jet radius of R = 0.2, 0.3, 0.4 and 0.5. The centrality dependence of the jet yield is characterized by the jet "central-to-peripheral ratio," Rcp. Jet production is found to be suppressed by approximately a factor of two in the 10% most central collisions relative to peripheral collisions. Rcp varies smoothly with centrality as characterized by the number of participating nucleons. The observed suppression is only weakly dependent on jet radius and transverse momentum. These results provide the first direct measurement of inclusive jet suppression in heavy ion collisions and complement previous measurements of dijet transverse energy imbalance at the LHC.Comment: 15 pages plus author list (30 pages total), 8 figures, 2 tables, submitted to Physics Letters B. All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/HION-2011-02

Risk factors for chronic ulceration in patients with varicose veins: A case control study

Background/ObjectiveIdentifying which patients with varicose veins are at risk of progressing to more severe forms of chronic venous disease could help in assigning clinical priorities and targeting appropriate treatments. The aim of this study was to determine, in subjects with varicose veins, the characteristics of venous disease and other factors associated with an increased risk of ulceration.MethodsOne hundred twenty subjects with varicose veins and an open or healed venous leg ulcer were compared with 120 controls with varicose veins and no history of venous ulcer on this case control study. Subjects were recruited from hospital settings and primary care. Each subject completed a questionnaire on lifestyle and medical history and underwent an examination comprising of clinical classification of venous disease (CEAP), duplex scanning, quantitative digital photoplethysmography, and measurement of dorsiflexion. Multiple logistic regression analyses and calculation of receiver operating characteristic (ROC) curves were performed to identify the combination of factors which most accurately predicted which patients with varicose veins will develop leg ulcers.ResultsAn increased risk of ulceration was associated with the severity of clinical venous disease, especially with the presence of skin changes (P < .0001). Other significant risk factors included history of deep vein thrombosis (DVT) (P = .001), higher body mass index (BMI) (P = .006), smoking (P = .009), and reflux in the deep veins (P = .0001). Ulceration was associated with reduced volume of blood displaced as reflected by photoplethysmography and a limited range of ankle movement (not wholly due to the effects of an active ulcer) (both P < .05). Multivariate analyses showed that skin changes including lipodermatosclerosis (odds ratio [OR] 8.90, 95% confidence interval [CI] 1.44-54.8), corona phlebectatica (OR 4.52, 95% CI 1.81-11.3) and eczema (OR 2.87, 95% CI 1.12-7.07), higher BMI (OR 1.08, 95% CI 1.01-1.15), and popliteal vein reflux (OR 2.82, 95% CI 1.03-7.75) remained independently associated with increased risk of ulceration while good dorsiflexion of the ankle (OR 0.88, 95% CI 0.81-0.97) and an effective calf muscle pump (OR 0.96, 95% CI 0.92-0.99) remained protective factors. ROC curve analyses indicated that a model based on clinical observation of skin changes, duplex scanning for popliteal reflux, and calf muscle pump tests would be the most accurate in determining which patients with varicose veins develop leg ulcers.ConclusionsThe results of this study confirm that, in patients with varicose veins, those with skin changes of chronic venous insufficiency and deep vein incompetence are at greatly increased risk of ulceration. However, the risks may also be increased in those who smoke, are obese, and have restricted ankle movement and reduced calf muscle pump power

The social Qualia of Kuml. An exploration of the iconicity of rune-stones with Kuml inscriptions from the Scandinavian Late Viking Age

This article discusses qualitative experiences (qualia) of Scandinavian Late Viking Age rune-stones from a semiotically theorized perspective. Rune-stones with kuml inscriptions receive particular attention. Despite the fact that kuml referred to different material entities, such as rune-stone, other standing stones, and/or grave, it is suggested that they resembled one another on iconic grounds. The quality associated with the multiple qualia was a sensation of safety that resulted in shared experiences that had positive social values. The article demonstrates that the semiotics of Peirce can be of great value to archaeologists who want to delve deeper into the social analysis of things