The Microcirculation In A Glioma Model

Microcirculatory functions in glial tumors are abnormal. High permeability leads to the formation of cerebral edema. Low blood flow may compromise the delivery of chemotherapeutic agents into tumor tissue. The purpose of this thesis was to examine the microcirculation in a glioma model in order to obtain a quantitative picture of how abnormal function relates to microvascular network structure.;A model of human malignant glioma was developed by implantation of multicellular spheroids into the brains of rats. The vessels in the tumor were permeable to exogenous tracers. Grossly, tracer leakage was correlated with tumor growth but microscopically, it appeared that in vivo leakage of serum protein was heterogeneous. Regional blood flow, as measured by autoradiography, was 57% lower in the tumor than in cortex. A combination of perfusion and injection techniques were used to resolve microvascular perfusion in the model. Stereologic and morphometric techniques were used for acquisition of data from digitized images of the brains. The total microvessel length in the tumor tissue was found to be 80% less than that in the cortex (222 {dollar}\pm{dollar} 15, 1093 {dollar}\pm{dollar} 49 mm/mm{dollar}\sp3{dollar}) (mean {dollar}\pm{dollar} standard error of the mean). However, only 50% (111 {dollar}\pm{dollar} 17 mm/mm{dollar}\sp3{dollar}) of the total length of vessel in the tumor was perfused. Because tumor microvessels were significantly wider in diameter (7.79 {dollar}\pm{dollar} 0.51, 3.81 {dollar}\pm{dollar} 0.14 {dollar}\mu{dollar}m) and longer (102 {dollar}\pm{dollar} 5, 64 {dollar}\pm{dollar} 4 {dollar}\mu{dollar}m) than microvessels in cortex, the total volume fraction of the microvascular compartment in the two tissues was not significantly different. However, the volume fraction actively perfused in the tumor was 50% less. The surface area of the microvascular compartment that would be functional in exchange under these conditions, was 50% of the total in tumor, and 80% of that in cortex. This heterogeneous perfusion of individual microvessels in viable tumor tissue may account for the low flow observed clinically and experimentally in intracranial tumors, and the heterogeneous leakage from microvessels in tumor tissue. Since the microvessels in tumors are very permeable, the flux of a substance into tumors is probably critically dependent on flow in the active volume

Governing public services in England and Wales: a move from the stakeholder model could further the democratic deficit

A great deal of attention is given to roles of both Chief Executives and members of the Senior Management Team in many organisations, yet the work of the governing board is frequently neglected. Comparing England and Wales, Jacqueline Baxter and Catherine Farrell argue that we’re witnessing a shift away from the predominantly stakeholder model of board membership, which could potentially further the ‘democratic deficit’ in the governance of public services

Comparison of Methods for Species-Tree Inference in the Sawfly Genus Neodiprion (Hymenoptera: Diprionidae)

Conifer-feeding sawflies in the genus Neodiprion provide an excellent opportunity to investigate the origin and maintenance of barriers to reproduction, but obtaining a phylogenetic estimate for comparative studies of Neodiprion speciation has proved difficult. Specifically, nonmonophyly within and discordance between individual gene trees, both of which are common in groups that diverged recently and/or rapidly, make it impossible to infer a species tree using methods that are designed to estimate gene trees. Therefore, in this study, we estimate relationships between members of the lecontei species group using four approaches that are intended to estimate species, not gene, trees: (1) minimize deep coalescences (MDC), (2) shallowest divergences (SD), (3) Bayesian estimation of species trees (BEST), and (4) a novel approach that combines concatenation with monophyly constraints (CMC). Multiple populations are sampled for most species and all four methods incorporate this intraspecific variation into estimates of interspecific relationships. We investigate the sensitivity of each method to taxonomic sampling, and, for the BEST method, we assess the impact of prior choice on species-tree inference. We also compare species-tree estimates to one another and to a morphologically based hypothesis to identify clades that are supported by multiple analyses and lines of evidence. We find that both taxonomic sampling and method choice impact species-tree estimates and that, for these data, the BEST method is strongly influenced by and branch-length priors. We also find that the CMC method is the least sensitive to taxonomic sampling. Finally, although interspecific genetic variation is low due to the recent divergence of the lecontei group, our results to date suggest that incomplete lineage sorting and interspecific gene flow are the main factors complicating species-tree inference in Neodiprion. Based on these analyses, we propose a phylogenetic hypothesis for the lecontei group. Finally, our results suggest that, even for very challenging groups like Neodiprion, an underlying species-tree signal can be extracted from multi-locus data as long as intraspecific variation is adequately sampled and methods that focus on the estimation of species trees are used. [Bayesian estimation of species trees (BEST); concatenation with monophyly constraints (CMC); gene-tree discordance; hybridization; introgression; lineage sorting; minimize deep coalescences (MDC); shallowest divergences (SD).]Organismic and Evolutionary Biolog

Setting the stage: scenic design and observers’ perceptions of the quality of public governance meetings

Whilst the importance of securing effective governance has been widely researched, seating configurations and the design of governance settings have not. Taking a dramaturgical perspective, this paper uses the conceptual language of scenic design to examine the relationship between meeting size, seating configurations, actor positioning and perceptions of public governance quality in UK council meetings. Using both quantitative and qualitative data, the paper finds strong support that those involved in public governance feel that seating configurations and actor posi�tioning are important considerations and that these factors can help to explain variation in perceptions of meetings’ public governance quality

Real Time Detection and Analysis of Facial Features to Measure Student Engagement with Learning Objects

This paper describes a software application that records student engagement in an on-screen task. The application records in real time the on-screen activity and simultaneously estimates the emotional state and head pose of the learner. The head pose is used to detect when the screen is being viewed and the emotional state provides feedback on the form of engagement. The application works without recording images of the learner. On completing the task, the percentage of time spent viewing the screen and statistics on emotional state (neutral, happy, sad) are produced. A graph depicting the learner’s engagement and emotional state synchronised with the screen captured video is also produced. It is envisaged that the tool will find application in learning activity and learning object design

Asylum narratives and credibility assessments: an ethnographic study of the asylum appeal process in Scotland

Abstract Asylum claimants regularly arrive in the UK without corroborating evidence to support their request for refugee protection. Consequently, an assessment of the credibility of the applicant’s account of persecution tends to become the focal point of asylum decision-making. In order for an applicant’s asylum claim to be assessed as factual, and therefore, credible it must be prepared in a way that conforms to the narrative models in legal discourse and meets the evidential requirements for showing past persecution and a future well-founded fear of persecution. It is for this reason, in part, that the role of legal practitioners becomes crucial. This thesis explores the ways that asylum solicitors deal with the issue of credibility in their daily working practices. It also examines the structural and procedural constraints which affect the working practices of solicitors when representing asylum clients in this way in asylum appeals. Based on ethnographic research conducted in Glasgow over an eighteen-month period, this thesis considers the ways that asylum solicitors approach credibility when representing asylum clients. This thesis explores the different forms of paid and unpaid labour undertaken by asylum solicitors and analyses how external factors such as legal aid funding arrangements affect the morale and working practices of solicitors who represent asylum claimants. It seeks to argue that a criminalising discourse exists in the asylum and immigration processes in Glasgow. Moreover, it demonstrates that such discourses extend to a cohort of asylum solicitors working in Glasgow and that the culture of disbelief which exists among these solicitors results in them regularly disbelieving their asylum clients’ accounts. Finally, by considering proposed changes to funding arrangements in Scotland, which would bring them in line with those in place in England and Wales, this thesis contends that were these arrangements to be introduced this would result in the underrepresentation of, and limited access to justice for, asylum applicants in Scotland