429 research outputs found

    CLASSIFICATION OF COMPLEX TWO-DIMENSIONAL IMAGES IN A PARALLEL DISTRIBUTED PROCESSING ARCHITECTURE

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    Neural network analysis is proposed and evaluated as a method of analysis of marine biological data, specifically images of plankton specimens. The quantification of the various plankton species is of great scientific importance, from modelling global climatic change to predicting the economic effects of toxic red tides. A preliminary evaluation of the neural network technique is made by the development of a back-propagation system that successfully learns to distinguish between two co-occurring morphologically similar species from the North Atlantic Ocean, namely Ceratium arcticum and C. longipes. Various techniques are developed to handle the indeterminately labelled source data, pre-process the images and successfully train the networks. An analysis of the network solutions is made, and some consideration given to how the system might be extended.Plymouth Marine Laborator

    Realcompact Alexandroff spaces and regular σ-frames

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    Bibliography: pages 96-103.In the early 1940's, A.D. Alexandroff [1940), [1941) and [1943] introduced a concept of space, more general than topological space, in order to obtain a simple connection between a space and the system of real-valued functions defined on it. Such a connection aided the investigation of the relationships between the linear functionals on these systems of functions and the additive set functions defined on the space. The Alexandroff spaces of this thesis are what Alexandroff himself called the completely normal spaces and what H. Gordon [1971) called the zero-set spaces

    Conflict management : the team New Zealand case

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    The primary subject matter of this case is the effectiveness of risk management strategies associated with the staging of a major international sporting event. A secondary issue examined in the case concerns the proprietary rights of employers to the intellectual capital and skills acquired by employees. The case requires an understanding of strategic risk management and good corporate governance principles.This case has a difficulty level that makes it most suitable for senior level students in a Corporate Governance/Business Ethics course. The case is designed to be taught in three class hours and would require about eight hours of out-of-class time which includes reading the case material and the articles listed in the references. <br /

    The Ursinus Weekly, October 17, 1974

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    N.A.B. named • Freshmen elect officers: Larry Dalaker president • Alumna corner: Color Day • Editorial • Bears are back • Letters to the editor: R.S.W. cut down; Wismer cut down; M.J.H. cut down; And again; Finally, thank you • Salinger myth dissolvedhttps://digitalcommons.ursinus.edu/weekly/1022/thumbnail.jp

    On the advance preparation of discrete finger responses

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    Most studies that examined the precuing of motor responses have been interpreted as indicating that response specification is a variable-order process. An apparent exception to this conclusion was obtained by The manner in which motor responses are prepared for execution is an important issue in the study of human movement More recently, several studies have employed a precuing (or priming) procedure in which the target stimulus is preceded by a cue stimulus that limits the possible response al

    Cord blood CD8⁺ T-cell expansion following granulocyte transfusions eradicates refractory leukemia

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    The action of hematopoietic cell transplantation in controlling leukemia is principally mediated by donor T cells directed against residual recipient malignant cells. However, its utility is limited by graft-versus-host disease (GVHD), where alloreactivity is extended beyond leukemic and marrow cells. In a human/murine chimeric model, we previously showed that the preferential infiltration of cord blood (CB) CD81 T cells eradicates an Epstein-Barr virus–driven lymphoblastoid tumor without causing xenogeneic GVHD. In the clinic, however, cord blood CD81 T-cell reconstitution is significantly delayed, and the observation of such a robust antileukemia effect mediated by cord blood CD81 T cells has not been reported. We describe an observation of very early T-cell expansion in 4 high-risk pediatric leukemia patients receiving third-party, pooled granulocytes after T cell–replete CB transplantation (CBT). The T-cell expansion was transient but robust, including expansion of CD81 T cells, in contrast to the delayed CD81 T-cell expansion ordinarily observed after T cell–replete CBT. The CD81 T cells were polyclonal, rapidly switched to memory phenotype, and had the ability to mediate cytotoxicity. This phenomenon is reproducible, and each patient remains in long-term remission without GVHD. The results suggest that fetal-derived CB CD81 T cells can be exploited to generate robust antileukemia effects without GVHD

    Nutrient Supply and Mercury Dynamics in Marine Ecosystems: A Conceptual Model

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    There is increasing interest and concern over the impacts of mercury (Hg) inputs to marine 32 ecosystems. One of the challenges in assessing these effects is that the cycling and trophic 33 transfer of Hg are strongly linked to other contaminants and disturbances. In addition to Hg, a 34 major problem facing coastal waters is the impacts of elevated nutrient, particularly nitrogen 35 (N), inputs. Increases in nutrient loading alter coastal ecosystems in ways that should change 36 the transport, transformations and fate of Hg, including increases in fixation of organic carbon 37 and deposition to sediments, decreases in the redox status of sediments and changes in fish 38 habitat. In this paper we present a conceptual model which suggests that increases in loading 39 of reactive N to marine ecosystems might alter Hg dynamics, decreasing bioavailabilty and 40 trophic transfer. This conceptual model is most applicable to coastal waters, but may also be 41 relevant to the pelagic ocean. We present information from case studies that both support and 42 challenge this conceptual model, including marine observations across a nutrient gradient; 43 results of a nutrient‐trophic transfer Hg model for pelagic and coastal ecosystems; observations 44 of Hg species, and nutrients from coastal sediments in the northeastern U.S.; and an analysis of 45 fish Hg concentrations in estuaries under different nutrient loadings. These case studies suggest 46 that changes in nutrient loading can impact Hg dynamics in coastal and open ocean ecosystems. 47 Unfortunately none of the case studies is comprehensive; each only addresses a portion of the 48 conceptual model and has limitations. Nevertheless, our conceptual model has important 49 management implications. Many estuaries near developed areas are impaired due to elevated 50 nutrient inputs. Widespread efforts are underway to control N loading and restore coastal 51 ecosystem function. An unintended consequence of nutrient control measures could be to 3 exacerbate 52 problems associated with Hg contamination. Additional focused research and 53 monitoring are needed to critically examine the link between nutrient supply and Hg 54 contamination of marine waters

    The targeted histone deacetylase inhibitor tefinostat (CHR-2845) shows selective in vitro efficacy in monocytoid-lineage leukaemias

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    Tefinostat (CHR-2845) is a novel monocyte/macrophage-targeted histone deacetylase (HDAC) inhibitor which is cleaved into its active acid by the intracellular esterase human carboxylesterase-1 (hCE-1). The in vitro efficacy of tefinostat was characterised in cell lines and in a cohort of 73 primary AML and CMML samples. Dose-dependent induction of apoptosis and significant growth inhibitory effects were seen in myelomonocytic (M4), monocytic/monoblastic (M5) and CMML samples in comparison to non-monocytoid AML sub-types (p = 0.007). Importantly, no growth inhibitory effects were seen in normal bone marrow CD34+ cells exposed to AML-toxic doses of tefinostat in clonogenic assays. Expression of hCE-1 was measured by intracellular flow cytometry and immunoblotting across the cohort, with highest levels seen in M5 AML patients. hCE-1 levels correlated with significantly increased tefinostat sensitivity (low EC50) as measured by growth inhibition assays (p = 0.001)and concomitant elevation of the mature monocytoid marker CD14+. Strong induction of intracellular histone protein acetylation was observed in tefinostat-responsive samples, as were high levels of the DNA damage sensor γ-H2A.X, highlighting potential biomarkers of patient responsiveness. Synergistic interaction between tefinostat and the current standard treatment cytarabine was demonstrated in dose response and clonogenic assays using simultaneous drug addition in primary samples (median Combination Index value = 0.51). These data provide a strong rationale for the further clinical evaluation of tefinostat in monocytoid-lineage haematological neoplasms including CMML and monocyte-lineage AMLs

    Time- and rate-dependent alterations of the QT interval precede the onset of torsade de pointes in patients with acquired QT prolongation.

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    Abstract Objectives. The purpose of this study was to determine whether the QT interval dynamics that precede torsade de pointes are consistent with the initiation of this arrhythmia by early afterdepolarization-induced triggered activity. Background. Early afterdepolarization-induced triggered activity has been suggested as an electrophysiologic mechanism for torsade de pointes. Consequently, the initiation of torsade de pointes should involve time- and rate-dependent alterations of ventricular repolarization similar to those known to modulate the development of early afterdepolarizations. Methods. RR and QT intervals were measured in digitized 24-h ambulatory electrocardiographic recordings obtained from seven patients with acquired prolongation of ventricular repolarization. Each patient had one or more episodes of torsade de pointes. The relation between RR and QT intervals was determined before, during and after multiple episodes of torsade de pointes. Results. In patients with multiple episodes of ventricular arrhythmias, the onset of the arrhythmias was associated with a critical prolongation of the QT interval. In some episodes, prolongation of the QT interval was associated with sudden prolongation of the sinus cycle length, whereas in other episodes, the QT interval prolonged progressively at a constant cycle length. Conclusions. The association between a critically prolonged QT interval and the onset of ventricular arrhythmias suggests that the initial complex of torsade de pointes is an early afterdepolarization-induced triggered response. However, prolongation of the QT interval itself was not sufficient to account for the initiation of torsade de pointes, suggesting that other, as yet unidentified factors are required. (J Am Coll Cardiol 1997;30:209–17

    Gene duplication and divergence produce divergent MHC genotypes without disassortative mating

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    Genes of the major histocompatibility complex (MHC) exhibit heterozygote advantage in immune defence, which in turn can select for MHC-disassortative mate choice. However, many species lack this expected pattern of MHC-disassortative mating. A possible explanation lies in evolutionary processes following gene duplication: if two duplicated MHC genes become functionally diverged from each other, offspring will inherit diverse multilocus genotypes even under random mating. We used locus-specific primers for high-throughput sequencing of two expressed MHC Class II B genes in Leach\u27s storm-petrels, Oceanodroma leucorhoa, and found that exon 2 alleles fall into two gene-specific monophyletic clades. We tested for disassortative vs. random mating at these two functionally diverged Class II B genes, using multiple metrics and different subsets of exon 2 sequence data. With good statistical power, we consistently found random assortment of mates at MHC. Despite random mating, birds had MHC genotypes with functionally diverged alleles, averaging 13 amino acid differences in pairwise comparisons of exon 2 alleles within individuals. To test whether this high MHC diversity in individuals is driven by evolutionary divergence of the two duplicated genes, we built a phylogenetic permutation model. The model showed that genotypic diversity was strongly impacted by sequence divergence between the most common allele of each gene, with a smaller additional impact of monophyly of the two genes. Divergence of allele sequences between genes may have reduced the benefits of actively seeking MHC-dissimilar mates, in which case the evolutionary history of duplicated genes is shaping the adaptive landscape of sexual selection
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