Experimental and Theoretical Modelling of 3D Gravity Currents

Postprint (published version

Bath

For centuries, the remains of the great Roman-British bathing and temple complex in the center of Bath have attracted the interest and imagination of countless visitors to the city. But there is more to the archaeology of Bath than its Roman monuments. Human settlement here has spanned ten millennia, dating back to the final retreat of the ice sheets from Britain at the close of the last Ice Age. Antiquarians, archaeologists and scholars have long been drawn not only to the Roman structures, but to the worked flint scattered on the hills and in the river silts around the town, the earthworks surviving on the surrounding uplands, and the great medieval Abbey that dominated the town from the 11th century. As a result, hundreds of recorded observations have been accumulated, stretching back to the 17th century, but augmented over the last century by increasing numbers of excavations, in many cases combined with meticulous research. This volume provides a collection and rigorous assessment of this accumulated information, much of which has to date been either unpublished or available only in obscure sources, and offers a synthesis of what this information tells us of Bath’s past.Part 1 comprises an overview of the area’s natural topography, a summary of antiquarian and early archaeological investigation, and a survey of the archaeological evidence available to us today. Part 2 collates the detailed archaeological evidence, summarizing earlier work, assessing the nature of the evidence, and setting out our informed understanding of Bath’s past. Lastly, Part 3 offers an overview of the current understanding of the archaeology of Bath, an assessment of the potential of the surviving deposits for providing new data, and suggestions for future research directions

Bath

For centuries, the remains of the great Roman-British bathing and temple complex in the center of Bath have attracted the interest and imagination of countless visitors to the city. But there is more to the archaeology of Bath than its Roman monuments. Human settlement here has spanned ten millennia, dating back to the final retreat of the ice sheets from Britain at the close of the last Ice Age. Antiquarians, archaeologists and scholars have long been drawn not only to the Roman structures, but to the worked flint scattered on the hills and in the river silts around the town, the earthworks surviving on the surrounding uplands, and the great medieval Abbey that dominated the town from the 11th century. As a result, hundreds of recorded observations have been accumulated, stretching back to the 17th century, but augmented over the last century by increasing numbers of excavations, in many cases combined with meticulous research. This volume provides a collection and rigorous assessment of this accumulated information, much of which has to date been either unpublished or available only in obscure sources, and offers a synthesis of what this information tells us of Bath’s past.Part 1 comprises an overview of the area’s natural topography, a summary of antiquarian and early archaeological investigation, and a survey of the archaeological evidence available to us today. Part 2 collates the detailed archaeological evidence, summarizing earlier work, assessing the nature of the evidence, and setting out our informed understanding of Bath’s past. Lastly, Part 3 offers an overview of the current understanding of the archaeology of Bath, an assessment of the potential of the surviving deposits for providing new data, and suggestions for future research directions

Snowdonia's early fieldscapes

Traces of stone and earthwork field boundaries, roundhouses and enclosures survive across extensive upland areas of northwest Wales. Collectively described as fieldscapes, they are among the best preserved and most complex examples of early land division in Europe. This thesis explores the human and environmental processes that led to their creation and survival between the first millennium BC and first millennium AD. It builds on relational approaches to land tenure, and considers the emergence of early land division as a long‐term phenomenon. The research is based on mapping from detailed topographic models created using existing airborne laser scanning (lidar) datasets. Archaeological remains that are difficult or impossible to observe on the ground were identified through analysis of these digital models, significantly increasing the number and geographic distribution of recorded features. The large sample size, rich metadata and consistency of the dataset provided a unique opportunity to develop new approaches to help analyse and understand these early fieldscapes. Innovative geospatial and geostatistical methods were developed to assess their cohesion, preservation and character. The results revealed new and distinctive patterns of enclosure bound up with detailed knowledge of and responses to the region’s varied landscape and local microtopography. People selected sunnier slopes to settle and farm, and they built low earthwork and stone banks to reduce the impact of prevailing winds. Across the mountainous terrain of Snowdonia, this created a network of curvilinear and irregular boundaries. On lower-lying slopes and flatter land, sinuosity was less pronounced, but boundary alignment appears to have responded to environmental conditions in a similar way. The importance of aspect and exposure suggests that further research should focus on exploring these characteristics and their relationship to the development of mixed farming practices

The relationship between web enjoyment and student perceptions and learning using a web-based tutorial

Web enjoyment has been regarded as a component of system experience. However, there has been little targeted research considering the role of web enjoyment alone in student learning using web-based systems. To address this gap, this study aims to examine the influence of web enjoyment on learning performance and perceptions by controlling system experience as a variable in the study. 74 students participated in the study, using a web-based tutorial covering subject matter in the area of 'Computation and algorithms'. Their learning performance was assessed with a pre-test and a post-test and their learning perceptions were evaluated with a questionnaire. The results indicated that there are positive relationships between the levels of web enjoyment and perceived usefulness and non-linear navigation for users with similar, significant levels of system experience. The implications of these findings in relation to web-based learning are explored and ways in which the needs of students who report different levels of web enjoyment might be met are discussed

Picture This! Community-Led Production of Alternative Views of the Heritage of Gwynedd

The digital camera has become ubiquitous. Every mobile phone has one built in, almost everyone has a mobile phone, and people use them constantly for all kinds of things, including taking pictures. In a new collaborative project, funded by the Arts and Humanities Research Council (AHRC), Bangor, Aberystwyth and Manchester Metropolitan Universities have teamed up with Gwynedd Archaeological Trust to develop tools to allow communities to picture their heritage and upload the images to an automated photogrammetry server to create metrical 3D models of the sites and objects they are recording. The data created will then feed into the local Historic Environment Record, providing a valuable tool for monitoring changes to heritage sites, while providing communities with added information and alternative views of their heritage. This paper is not intended to provide a formal research design or a fully developed prototype. Rather, it is intended to outline an experimental and collaborative approach that is situated as both practice and research, with neither enterprise being privileged over the other. The activities outlined here will be developed and evaluated over the next year and a half, after which we will report on whether or how the contingent aims and outcomes expressed were realized

Quark droplets stability induced by external magnetic field

The influence of a constant homogeneous external magnetic field $H$ on the formation and stability of quark droplets is investigated within a simple Nambu -- Jona-Lasinio model by using a thermodynamic approach. For a vanishing magnetic field stable quark droplets, which are schematically the bags of massless quarks, are allowed to exist only at $G>G_{bag}$, where $G$ is the quark coupling constant, $G_{bag}=1.37G_{crit}$, and $G_{crit}$ is the value of the coupling constant above which chiral symmetry is spontaneously broken down. On the other hand, a nonvanishing external magnetic field can induce the stability of quark droplets so that they may exist even at $G<G_{bag}$. In this case, depending on the value of $H$, quark droplets are composed either of massive or massless quarks.Comment: 16 pages, 9 figures, REVTEX4; new references added; minor changes of the tex

Conformal Transformations in Cosmology of Modified Gravity: the Covariant Approach Perspective

The 1+3 covariant approach and the covariant gauge-invariant approach to perturbations are used to analyze in depth conformal transformations in cosmology. Such techniques allow us to obtain very interesting insights on the physical content of these transformations, when applied to non-standard gravity. The results obtained lead to a number of general conclusions on the change of some key quantities describing any two conformally related cosmological models. In particular, it is shown that the physics in the Einstein frame has characteristics which are completely different from those in the Jordan frame. Even if some of the geometrical properties of the cosmology are preserved (homogeneous and isotropic Universes are mapped into homogeneous and isotropic universes), it can happen that decelerating cosmologies are mapped into accelerated ones. Differences become even more pronounced when first-order perturbations are considered: from the 1+3 equations it is seen that first-order vector and tensor perturbations are left unchanged in their structure by the conformal transformation, but this cannot be said of the scalar perturbations, which include the matter density fluctuations. Behavior in the two frames of the growth rate, as well as other evolutionary features, like the presence or absence of oscillations, etc., appear to be different too. The results obtained are then explicitly interpreted and verified with the help of some clarifying examples based on $f(R)$-gravity cosmologies.Comment: 26 pages, 8 figure

Evidence for a heritable predisposition to Chronic Fatigue Syndrome

<p>Abstract</p> <p>Background</p> <p>Chronic Fatigue Syndrome (CFS) came to attention in the 1980s, but initial investigations did not find organic causes. Now decades later, the etiology of CFS has yet to be understood, and the role of genetic predisposition in CFS remains controversial. Recent reports of CFS association with the retrovirus xenotropic murine leukemic virus-related virus (XMRV) or other murine leukemia related retroviruses (MLV) might also suggest underlying genetic implications within the host immune system.</p> <p>Methods</p> <p>We present analyses of familial clustering of CFS in a computerized genealogical resource linking multiple generations of genealogy data with medical diagnosis data of a large Utah health care system. We compare pair-wise relatedness among cases to expected relatedness in the Utah population, and we estimate risk for CFS for first, second, and third degree relatives of CFS cases.</p> <p>Results</p> <p>We observed significant excess relatedness of CFS cases compared to that expected in this population. Significant excess relatedness was observed for both close (p <0.001) and distant relationships (p = 0.010). We also observed significant excess CFS relative risk among first (2.70, 95% CI: 1.56-4.66), second (2.34, 95% CI: 1.31-4.19), and third degree relatives (1.93, 95% CI: 1.21-3.07).</p> <p>Conclusions</p> <p>These analyses provide strong support for a heritable contribution to predisposition to Chronic Fatigue Syndrome. A population of high-risk CFS pedigrees has been identified, the study of which may provide additional understanding.</p