223 research outputs found

    MACS: Multi-agent COTR system for Defense Contracting

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    The field of intelligent multi-agent systems has expanded rapidly in the recent past. Multi-agent architectures and systems are being investigated and continue to develop. To date, little has been accomplished in applying multi-agent systems to the defense acquisition domain. This paper describes the design, development, and related considerations of a multi-agent system in the area of procurement and contracting for the defense acquisition community

    Overlapping promoter targeting by Elk-1 and other divergent ETS-domain transcription factor family members

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    ETS-domain transcription factors play important roles in controlling gene expression in a variety of different contexts; however, these proteins bind to very similar sites and it is unclear how in vivo specificity is achieved. In silico analysis is unlikely to reveal specific targets for individual family members and direct experimental approaches are therefore required. Here, we take advantage of an inducible dominant-negative expression system to identify a group of novel target genes for the ETS-domain transcription factor Elk-1. Elk-1 is thought to mainly function through cooperation with a second transcription factor SRF, but the targets we identify are largely SRF-independent. Furthermore, we demonstrate that there is a high degree of overlapping, cell type-specific, target gene binding by Elk-1 and other ETS-domain transcription factors. Our results are therefore consistent with the notion that there is a high degree of functional redundancy in target gene regulation by ETS-domain transcription factors in addition to the specific target gene regulation that can be dictated through heterotypic interactions exemplified by the Elk-1-SRF complex

    Human Mas-related G protein-coupled receptors-X1 induce chemokine receptor 2 expression in rat dorsal root ganglia neurons and release of chemokine ligand 2 from the human LAD-2 mast cell line

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    Primate-specific Mas-related G protein-coupled receptors-X1 (MRGPR-X1) are highly enriched in dorsal root ganglia (DRG) neurons and induce acute pain. Herein, we analyzed effects of MRGPR-X1 on serum response factors (SRF) or nuclear factors of activated T cells (NFAT), which control expression of various markers of chronic pain. Using HEK293, DRG neuron-derived F11 cells and cultured rat DRG neurons recombinantly expressing human MRGPR-X1, we found activation of a SRF reporter gene construct and induction of the early growth response protein-1 via extracellular signal-regulated kinases-1/2 known to play a significant role in the development of inflammatory pain. Furthermore, we observed MRGPR-X1-induced up-regulation of the chemokine receptor 2 (CCR2) via NFAT, which is considered as a key event in the onset of neuropathic pain and, so far, has not yet been described for any endogenous neuropeptide. Up-regulation of CCR2 is often associated with increased release of its endogenous agonist chemokine ligand 2 (CCL2). We also found MRGPR-X1-promoted release of CCL2 in a human connective tissue mast cell line endogenously expressing MRGPR-X1. Thus, we provide first evidence to suggest that MRGPR-X1 induce expression of chronic pain markers in DRG neurons and propose a so far unidentified signaling circuit that enhances chemokine signaling by acting on two distinct yet functionally co-operating cell types. Given the important role of chemokine signaling in pain chronification, we propose that interruption of this signaling circuit might be a promising new strategy to alleviate chemokine-promoted pain

    Hegel and global politics: communitarianism or cosmopolitanism?

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    This article discusses Hegel’s views on global politics by relating them to the ‘communitarianism versus cosmopolitanism’ debate. I distinguish between three different theoretical positions and three different readings of Hegel, which I associate with the notions of ‘communitarianism,’ ‘strong cosmopolitanism’ and ‘weak cosmopolitanism’ respectively. Contrary to a commonly held view that Hegel is not a cosmopolitan thinker at all, in any sense of the term, I argue that he is best thought of as a weak cosmopolitan thinker rather than a communitarian or a strong cosmopolitan advocate of the idea of a world-state. In passing, the article refers to the relationship which exists between Hegel’s ideas and those of three Twentieth Century theorists who might be associated with these theoretical positions and these different readings of Hegel, namely, Carl Schmitt, Alexandre Kojève and Jurgen Habermas. The article also refers to the methodological problems which are confronted by readers of Hegel’s writings who wish to apply his ideas to the problems of global politics today. Here I refer to a distinction which I have made elsewhere between different kinds of reading, namely the interpretation, appropriation and the reconstruction of texts, which is especially relevant for readers of the works of Hegel

    Analysing Change: Complex Rather than Dialectical?

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    The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.This article offers a discussion of dialectics from a complexity perspective. Dialectics is a term much utilized but infrequently defined. This article suggests that a spectrum of ideas exist concerning understandings of dialectics. We are particularly critical of Hegelian dialectics, which we see as anthropocentric and teleological. While Marxist approaches to dialectics, in the form of historical materialism, marked a break from the idealist elements of Hegelian dialectics, they retained traces of this approach. The article offers a partial discussion of essential elements of dialectics, which we consider to be the analysis of change, the centrality of contradiction, and the methodology of abstraction. Points of overlap with complexity thinking are highlighted, together with those points where complexity thinking and dialectical approaches diverge. We conclude with some suggestions as to how complexity thinking might contribute to a development of dialectical approaches

    Dimer formation and conformational flexibility ensure cytoplasmic stability and nuclear accumulation of Elk-1

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    The ETS (E26) protein Elk-1 serves as a paradigm for mitogen-responsive transcription factors. It is multiply phosphorylated by mitogen-activated protein kinases (MAPKs), which it recruits into pre-initiation complexes on target gene promoters. However, events preparatory to Elk-1 phosphorylation are less well understood. Here, we identify two novel, functional elements in Elk-1 that determine its stability and nuclear accumulation. One element corresponds to a dimerization interface in the ETS domain and the second is a cryptic degron adjacent to the serum response factor (SRF)-interaction domain that marks dimerization-defective Elk-1 for rapid degradation by the ubiquitin–proteasome system. Dimerization appears to be crucial for Elk-1 stability only in the cytoplasm, as latent Elk-1 accumulates in the nucleus and interacts dynamically with DNA as a monomer. These findings define a novel role for the ETS domain of Elk-1 and demonstrate that nuclear accumulation of Elk-1 involves conformational flexibility prior to its phosphorylation by MAPKs

    ELK1 Uses Different DNA Binding Modes to Regulate Functionally Distinct Classes of Target Genes

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    Eukaryotic transcription factors are grouped into families and, due to their similar DNA binding domains, often have the potential to bind to the same genomic regions. This can lead to redundancy at the level of DNA binding, and mechanisms are required to generate specific functional outcomes that enable distinct gene expression programmes to be controlled by a particular transcription factor. Here we used ChIP–seq to uncover two distinct binding modes for the ETS transcription factor ELK1. In one mode, other ETS transcription factors can bind regulatory regions in a redundant fashion; in the second, ELK1 binds in a unique fashion to another set of genomic targets. Each binding mode is associated with different binding site features and also distinct regulatory outcomes. Furthermore, the type of binding mode also determines the control of functionally distinct subclasses of genes and hence the phenotypic response elicited. This is demonstrated for the unique binding mode where a novel role for ELK1 in controlling cell migration is revealed. We have therefore uncovered an unexpected link between the type of binding mode employed by a transcription factor, the subsequent gene regulatory mechanisms used, and the functional categories of target genes controlled
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