577 research outputs found

    Replicated Secure Shared Objects for Groupware Applications

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    This report describes the design and implementation of a secure shared replicated objects system, intended for use by groupware application programmers. The system enables such programmers to incorporate conceptually shared objects into their programs in order to provide the users with access to shared information. Access to each object is restricted to trusted parties by applying access control to its methods. Our system is different from existing implementations because it employs a replicated architecture. We believe that replication of the data is essential in order to achieve acceptable interactive performance levels when invoking methods that read the object state and indeed we show that such methods are significantly faster than a similar secure shared object system which is based on a client-server architecture which does not employ replication. The implementation includes a secure group communications system, the design of which is also included in this report. 1 Introductio

    A Security Architecture for Distributed Groupware

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    Submitted to the University of London for the Degree of Doctor of Philosoph

    The evolution of inflammatory mediators

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    Invertebrates do not display the level of sophistication in immune reactivity characteristic of mammals and other ‘higher’ vertebrates. Their great number and diversity of forms, however, reflect their evolutionary success and hence they must have effective mechanisms of defence to deal with parasites and pathogens and altered self tissues. Inflammation appears to be an important first line defence in all invertebrates and vertebrates. This brief review deals with the inflammatory responses of invertebrates and fish concentrating on the cell types involved and the mediators of inflammation, in particular, eicosanoids, cytokines and adhesion molecules

    AN EXAMINATION OF MINDFULNESS AND COGNITIVE INTERFERENCE IN AMERICAN VETERANS OF THE GLOBAL WAR ON TERRORISM

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    Utilizing an internet-based research protocol, PTSD symptoms, mindfulness skills, and cognitive interference were assessed. Participants completed self-report measures of PTSD symptoms and mindfulness skills, and then completed an emotional Stroop task that contained words selected to induce cognitive interference based on their combat-related nature. Consistent with past research, this study hypothesized that participants with combat-related PTSD would have longer response latencies on the task relative to participants with lower scores on a combat-related PTSD measure. This study also hypothesized that veterans in general would exhibit longer response latencies that non-veterans. This study was also hypothesized that mindfulness skills would moderate this prolonged response latency. Specifically, I expected participants with higher scores on a self-report measure of mindfulness to exhibit decreased response latency relative to those participants with similar PTSD scores and lower mindfulness scores. These three hypotheses were not supported in the present study. Limitations of the study and implications for future research are also discussed

    Measuring Air Quality via Multimodal AI and Satellite Imagery

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    Climate change may be classified as the most important environmental problem that the Earth is currently facing, and affects all living species on Earth. Given that air-quality monitoring stations are typically ground-based their abilities to detect pollutant distributions are often restricted to wide areas. Satellites however have the potential for studying the atmosphere at large; the European Space Agency (ESA) Copernicus project satellite, "Sentinel-5P" is a newly launched satellite capable of measuring a variety of pollutant information with publicly available data outputs. This paper seeks to create a multi-modal machine learning model for predicting air-quality metrics where monitoring stations do not exist. The inputs of this model will include a fusion of ground measurements and satellite data with the goal of highlighting pollutant distribution and motivating change in societal and industrial behaviors. A new dataset of European pollution monitoring station measurements is created with features including altitude, population, etc.\textit{altitude, population, etc.} from the ESA Copernicus project. This dataset is used to train a multi-modal ML model, Air Quality Network (AQNet) capable of fusing these various types of data sources to output predictions of various pollutants. These predictions are then aggregated to create an "air-quality index" that could be used to compare air quality over different regions. Three pollutants, NO2_2, O3_3, and PM10_{10}, are predicted successfully by AQNet and the network was found to be useful compared to a model only using satellite imagery. It was also found that the addition of supporting data improves predictions. When testing the developed AQNet on out-of-sample data of the UK and Ireland, we obtain satisfactory estimates though on average pollution metrics were roughly overestimated by around 20\%.Comment: 14 pages, 9 figures, 4 table

    Professions, class and society:solicitors in 19th century Birmingham

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    The thesis provides an analysis of an occupation in the process of making itself a profession. The solicitors' profession in Birmingham underwent a great many changes during the 19th century against a background of industrialisation and urbanisation. The solicitors' conception of their status and role, in the face of these challenges, had implications for successful strategies of professionalisation. The increased prestige and power of the profession, and especially its elite, are examined in their social context rather than in terms of a technical process, or educational and organisational change. The thesis argues that -the profession's social relationships and broad concerns were significant in establishing solicitors as "professional men". In particular these are related to the profession's efforts to gain control of markets for legal services and increase social status. In the course of achieving these aims a concept of profession and a self-image were articulated by solicitors in order to persuade society and the state of the legitimacy of their claims. The concept of the gentlemanly professional was of critical importance in this instance. The successful creation of a provincial professional "community" by the end of the 19th century rested principally on a social and moral conception of professionalism rather than one which stressed specialised training and knowledge, professional organisations and credentials

    The diarrhetic shellfish-poisoning toxin, okadaic acid, provokes gastropathy, dysbiosis and susceptibility to bacterial infection in a non-rodent bioassay, Galleria mellonella

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    Diarrhetic shellfish-poisoning (DSP) toxins such as okadaic acid and dinophysistoxins harm the human gastrointestinal tract, and therefore, their levels are regulated to an upper limit of 160 μg per kg tissue to protect consumers. Rodents are used routinely for risk assessment and studies concerning mechanisms of toxicity, but there is a general move toward reducing and replacing vertebrates for these bioassays. We have adopted insect larvae of the wax moth Galleria mellonella as a surrogate toxicology model. We treated larvae with environmentally relevant doses of okadaic acid (80–400 μg/kg) via intrahaemocoelic injection or gavage to determine marine toxin-related health decline: (1) whether pre-exposure to a sub-lethal dose of toxin (80 μg/kg) enhances susceptibility to bacterial infection, or (2) alters tissue pathology and bacterial community (microbiome) composition of the midgut. A sub-lethal dose of okadaic acid (80 μg/kg) followed 24 h later by bacterial inoculation (2 × 105 Escherichia coli) reduced larval survival levels to 47%, when compared to toxin (90%) or microbial challenge (73%) alone. Histological analysis of the midgut depicted varying levels of tissue disruption, including nuclear aberrations associated with cell death (karyorrhexis, pyknosis), loss of organ architecture, and gross epithelial displacement into the lumen. Moreover, okadaic acid presence in the midgut coincided with a shift in the resident bacterial population over time in that substantial reductions in diversity (Shannon) and richness (Chao-1) indices were observed at 240 μg toxin per kg. Okadaic acid-induced deterioration of the insect alimentary canal resembles those changes reported for rodent bioassays
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