1,721,230 research outputs found
John Timothy Tim Price
Full text linkJohn_Timothy--Tim--Price.pdf - Funeral program for John Timothy Pricehttps://digitalcommons.georgiasouthern.edu/willowhillheritage-obituaries/10703/thumbnail.jp
Train station in Randolph, Alabama.
No full textThis photograph was taken by John Timothy Morgan Weeks, a longtime resident of Randolph
Anti-idiotypic immunity against AB cell lymphoma
No full textThe idiotypic determinants carried on the surface immunoglobulin molecules of B cell tumours can function as highly specific tumour associated antigens. In this study I have shown that immunisation of BALB/c mice with idiotypic IgM derived from the syngeneic lymphoma BCL1 can specifically protect the animals from subsequent challenge with BCL1 tumour, with 70/90 immunised mice surviving > 100 days post challenge, compared to control animals which survived a mean of 40 days. In addition the immunisation of mice, which had been previously inoculated with BCL1 tumour, with BCL1 IgM conjugated to keyhole limpet hemacyanin proved effective in the treatment of established disease. Both idiotype specific T cells and cytotoxic antibody have been demonstrated to be induced by immunisation. Passive transfer experiments have suggested that idiotype specific antibody may be implicated in the protection, and no role for the immune cells could be demonstrated. However the levels of anti-idiotypic antibody seen in immunised animals did not correlate with the survival seen following challenge with BCL1. Tumour cells inoculated into immunised animals were not completely eradicated, but could remain in a dormant state in the spleen of the animals for long periods of time (> 6 months). The presence of such dormant tumour cells was demonstrated by immunohistological techniques and the emergence of tumour in the recipients of spleen cells from apparently healthy long term survivors. Escape of the tumour from the dormant state was associated with a population of cells that neither expressed idiotypic IgM on their surface, nor secreted it in vivo or in vitro. The cells did, however, contain idiotypic material in their cytoplasm. A stable variant of the BCL1 tumour, SNAG 1, was isolated with this phenotype. In initial experiments to determine the genetic lesion underlying the altered phenotype of SNAG 1 cells no difference between the molecular weight of the IgM heavy and light chains could be demonstrated. The SNAG 1 tumour also has a different pattern of growth from BCL1; it takes longer to grow and kill the animals and it shows a relatively greater liver involvement than BCL1. It also fails to respond to lipopolysaccharide by either proliferation or secretion of idiotypic IgM. This variant, therefore, not only documents a novel mechanism whereby tumour cells can escape from an anti-idiotype immune response, but may also prove a valuable tool in determining the role of surface immunoglobulin in cell migration and response to growth factors. The use of idiotypic vaccination may prove useful in the therapy of human lymphoma. The emergence of variants similar to SNAG 1 may prove an obstacle to the success of such an approach, but the slow growth of SNAG 1 suggests that such immunoselected variants may have a more benign course.</p
Quantal analysis of synaptic transmission in CA1 pyramidal cells of the rat hippocampus
No full textThe hippocampal formation is an area of the limbic system involved in a number of brain functions including learning and memory. It is also involved in the pathogenesis of epilepsy. Using the recently developed recording technique of whole-cell patch-clamp in brain slices, the synaptic and cellular mechanisms of CA1 pyramidal neurons were investigated in rat hippocampal slices in vitro. Two components to the excitatory postsynapti currents (EPSCs), evoked by afferent stimulation, were observed, a fast AMPA receptor-mediated event accounting for 90-95% of peak EPSC amplitude, and a small, slow NMDA receptor-mediated component. The local anaesthetic, N-(2,6-dimethyl-phenylcarbamoylmethyl)triethylammonium bromide (QX-314; 10-20mM), was found to block all voltage-gated Na+ conductances in CA1 cells when applied intracellularly, and blocked a conductance which exhibited characteristics of the anomalous rectifier IQ. EPSCs, however, were not blocked by intracellular QX-314. The space-clamp properties of CA1 cells were also investigated. The incomplete voltage control of EPSCs and voltage-gated Ca2+ currents indicated that CA1 pyramidal cells were poorly space-clamped. However, proximal areas of the cell were under better voltage control than the distal. Excitatory synaptic transmission in area CA1 was investigated using quantal analysis. EPSCs were evoked by a minimal stimulation protocol with a `bridge' of axons sectioned in the stratum radiatum between the stimulating and recording sites. Precise positioning of a monopolar stimulating electrode enabled a small population of synapses to be selectively activated, and this was confirmed by input-output relationships. Data sets were analysed using Bayesian statistics and amplitude distributions were constructed. Initial studies indicated only a low number of data sets exhibiting regular fluctuations in EPSC amplitude. However, non-equivalent subsets of EPSCs were observed within the majority of data sets, which exhibited different rise times and quantal amplitudes. Data sets separated into subsets with `fast' and `slow' rise times, exhibited regular quantal fluctuations in EPSC amplitude, providing strong evidence for quantal transmission at these synapses.</p
A study of morphological variation in Halimione portulacoides (L.) Aell., in relation to variations in the habitat.
No full textMapping and transect work at three sites in the Hampshire basin indicated that the main habitat feature affecting the distribution and quantity of Halimione protulacoides was water content of the substrate, this being the result of several factors interacting: configuration of the area, height above Ordnance Datum and nature of the substrate. Marked morphological differences were observed between plants growing on different substrates, three main types being recognised in the initial, subjective, examination: much-branched, non-rooting, prostrate, on pebble; prostrate, with much rooting, on sand; lax, upright and non-rooting, on mud. Since, with apparent relative genetical uniformity of Halimione in the Hampshire basin, there were indications of habitat differences affecting its morphology, separate objective multivariate analyses were carried out on habitat and morphology data. These analyses sho'ved that there was a high correlation betw'een habitat and the morphology of Halimione portulacoides var. latifolia, with the three 'types' forming part of a continuous series. It</p
Econometric modelling of nonlinearity and nonstationarity in the foreign exchange market
No full textThis thesis comprises of four major papers concerning the econometric modelling of the foreign exchange market. Taken together the papers strongly suggest that a new paradigm for the study of financial markets is emerging, based on transient statistical properties and computational agent based models. I propose that consideration of the latter are critical if we are to meaningfully exploit the new territory offered by the current glut of nonlinearity and nonstationarity tests and models. I demonstrate how statistical properties are variably detectable through time, and discuss what this means for testing and modelling techniques.In response to the existing and rather negative nonlinear forecastability literature, I explore the idea that as nonlinearity is only occasionally detectable, it follows that nonlinear forecastability ought to be transient as well. I show that whilst over large samples we might not detect any forecast improvements, there are indeed sub-periods in which both significant point and direction forecastability can be uncovered. By applying concepts developed for the stability analysis of nonlinear dynamical systems I provide evidence that the occurrence of such periods of predictability may itself be predictable.Building on this idea I introduce a novel statistical modelling framework which combines aspects of mixture modelling and computational learning. I thoroughly present the model in context with other more familiar econometric models, and add to the literature on this model by providing evidence on the ability of the model to recover conditional statistical properties. In common with many nonlinear models the model I propose presents difficult inference problems. In fact the central problem of determining the number of mixture components is as yet unsolved. I add to the mixture inference literature by thoroughly surveying the existing proposals, and making a number of novel suggestions for improved inference methods. I explore the practical performance of such inference methods via a number of simulation studies. A number of applications of the model demonstrate it is able to replicate many of the stylized facts of exchange rate data, and provide good forecasts out-of-sample.</p
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
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