1,721,127 research outputs found
Video rate textured image generation with anti-aliasing enhancements
No full textThis thesis explores several issues in the field of video-rate texture mapped imagery generation. Two key areas in particular are examined, these being the development of a cost-effective image generator, which has potential both as a high-performance system and as a test bed for future research, and the enhancement of the subjective image quality by suppression of the aliasing artifacts.The development of a video rate textured image generator is first presented. This system uses the ray tracing image generation method for evaluating the mapping between screen and texture spaces. The ray tracing algorithm is organised to generate pixels in a raster scan order and is synchronized to the screen refresh signals which results in the elimination of the image framestore. Images are generated at a high refresh rate, in order to minimise the overall response time of the system.The process by which the subjective quality of the textured images is enhanced is considered next. A spatially-variant method is devised which suppresses aliasing by progressively reducing the contrast of the image at the points where artifacts will occur. This method takes advantage of previously computed results in the image generator in order to determine the points in the image where aliasing suppression should be applied. This method does not require extra texture memory to store pre-computed results as is the case with other more conventional approaches.In addition to the other areas examined, the use of an alternative colourspace for texture representation is investigated. The use of the YUV colourspace, as used in television broadcasting systems, in conjunction with a novel colour value encoding method is shown to reduce texture memory requirements as well as simplifying processing.</p
The Molecular regulation of apoptosis in b-cell neoplasms
No full textLeukaemia and lymphoma represent the ninth and tenth most-common malignancies in the UK. Currently, therapeutic strategies utilise both chemotherapy and radiotherapy alongside the anti-CD20 monoclonal antibody Rituximab. Whilst such treatment regimes can yield impressive results, resistance and disease relapses are common. Therefore, additional therapies are required to improve patient survival and quality of life. Eliciting specific death of tumour cells and understanding the molecular mechanisms responsible provides a rational approach for developing these new therapies. One form of cell death induced in response to physiological or exogenous stress stimuli, oncogenic changes, or an absence of survival factors is termed apoptosis and is primarily regulated by the BH3-only subgroup of the Bcl-2 family.Here, the regulation of this family of proteins was examined in a selection of murine lymphoma and leukaemia models after a selection of different apoptosis-inducing stimuli. Utilising a panel of primary murine lymphomas deficient in specific BH3-only genes, this investigation dissected the apoptotic cellular response to B cell receptor (BCR) and also TGF-β signalling. BCR signalling invoked a temporally biphasic cell death response, exhibiting both the hallmarks of apoptotic and non-apoptotic cell death. The BH3-only proteins Bim, Noxa, and Bik played key roles in BCR-induced apoptosis, whilst only Bik appeared important in the non-apoptotic phase of cell death. Such upregulation of Bim and Bik appeared dependent upon the function of ERK and Syk kinases, respectively. Thereby, identifying a link between BCR signalling and specific death effector mechanisms. TGF-β signalling, however, was linked to the induction of the BH3-only protein Puma, which played a vital role in the rapid induction of apoptosis. Finally, two new models of B cell malignancy (Tcl-1, IgHTEµ) were established and characterised in the laboratory with the aim of addressing the general suitability of the BCR as a therapeutic target and the key role of Bim in the death response.Together, these studies further our knowledge of how BCR and TGF-β signalling evoke apoptosis in lymphoma cells, highlight the diversity of BH3-only proteins involved, and provide a series of models in which to undertake rational combination therapies.We anticipate that the knowledge gained will help to develop future therapeutic strategies, allowing targeting of specific aspects of tumour biology, in order to improve overall patient survival
An experimental investigation on fluid transfer mechanisms in ultramafic rocks
No full textStatic annealing and crack-cook experiments were performed on wet and dry fabricated San Carlos olivine aggregates and a core of Balsam Gap dunite to investigate fluid infiltration mechanisms for low-permeability mantle rocks. Deionized water (30–40 μL) was added to cold-pressed olivine powders before hot-pressing to make wet samples; samples hot-pressed without added water are dry (<30 H/106 Si). Talc was added to all samples to provide fluid during the experiments. All samples were annealed at 1200 °C and 300 MPa confining pressure for 3 h, but crack-cook experiments were subjected to a 300–500 MPa axial differential stress at 600 °C and 125 MPa confining pressure before annealing. All samples contain abundant fluid inclusions (FIs) after annealing. Olivine aggregate samples show FI-rich and FI-depleted regions. Grain size was reduced in all samples, particularly in FI-rich regions. Crosscutting FIs associated with fractures are only widespread in the dunite. Fluids were primarily transferred from talc along grain boundaries in olivine aggregate samples and along fractures in dunite. FIs inhibit grain growth and grain-boundary migration, leading to smaller than expected grain sizes at the experimental conditions. Results have important implications where excess fluid may affect grain-size sensitive deformation mechanisms in the upper oceanic lithosphere.Support from the National Science Foundation grant EAR-1347309 is gratefully acknowledged.Final manuscript post peer review, without publisher's formatting or copy
editing (postprint)This version of the article is available for viewing to the public after July 26, 2021
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
koamabayili/VECTRON-author-checklist: VECTRON author checklist
No full textWe have done our best to complete the author checklist relating to the use of animals in the hut study. Note that the objective for the hut study was to evaluate the IRS treatment applications for residual efficacy against Anopheles mosquitoes, including the local An. coluzzii mosquito population. Cows were only used to attract mosquitoes into the huts and no tests were carried out directly on the cows. The author checklist is intended for use with studies where experiments are carried out on animals, which is why we have had such difficulty in completing this for the hut study, as many of the questions do not relate to how the cows were used
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