4,036 research outputs found

    Tropicalization of classical moduli spaces

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    The image of the complement of a hyperplane arrangement under a monomial map can be tropicalized combinatorially using matroid theory. We apply this to classical moduli spaces that are associated with complex reflection arrangements. Starting from modular curves, we visit the Segre cubic, the Igusa quartic, and moduli of marked del Pezzo surfaces of degrees 2 and 3. Our primary example is the Burkhardt quartic, whose tropicalization is a 3-dimensional fan in 39-dimensional space. This effectuates a synthesis of concrete and abstract approaches to tropical moduli of genus 2 curves.Comment: 33 page

    GOVERNANCE MECHNISMS IN IS OUTSOURCING PROJECTS IN TRANSITION ECONMIES

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    Pevious IS outsourcing research studies failed to provide evidences on how IT client-vendor relationships should be governed to ensure project success and relational continuity. More importantly, it is even challenging for companies to achieve outsourcing success in transition economies facing an environment characterized by institutional instability. This article draws from theories of institutions and organizations to develop a model examining outsourcing relationship governance mechanisms which would affect outsourcing success in state-owned and non-state-owned Chinese companies. Results of 72 state-owned and 54 non-state-owned outsourcing projects show that the positive relationship between contractual governance and outsourcing success is stronger in state-owned firms than in non-state-owned firms. On the other hand, non-state-owned firms have stronger effects on the relationships between relational governance and outsourcing success, and between outsourcing success and relational continuity

    NutriColoring:designing a doodling toolkit to support daily self-reported dietary assessment among office workers

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    This study was motivated by a desire to help working-age individuals gain a better understanding of their daily nutritional intakes with a new self-reported dietary assessment method because an unhealthy eating behavior increases the risks of developing chronic diseases. In this study, we present the design and evaluation of NutriColoring, a food diary that leverages doodling on sketches to report and reflect on everyday diet in the working context. Through a 2-week field study involving 18 participants, the usefulness of NutriColoring in facilitating dietary assessment was tested by making comparisons with the typical bullet diary method. Our quantitative results showed that NutriColoring provided users with improved dietary assessment experience and intrinsic motivations, with significantly low task frustration and high enjoyment. Because of the freedom and playfulness in reporting intakes at work, the interview findings showed a high acceptance of employing NutriColoring at work. This article is concluded with a set of implications for the design and development of a Doodling toolkit to support healthy eating behaviors among office worker

    A Study Of Sustaining Firm Competitive Advantage Through Its Image

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    A mass of literature exists promoting the benefits of resource-based theory of the organization.  This literature suggests that business-level resources may be sources of competitive advantage if they are rare, valuable, nonsubstitutable, and difficult to imitate.  Unfortunately, applying this theory to research or practice requires that the study first identify specific resources that can be measured and investigated.  It also requires that this study develops and tests separate theories to explain how these resources are related to competitive advantage.  Only through these steps will this study be able to extend the resource-based view of the organization in explaining and affecting competitive advantage efforts.  The overarching theory (i.e., resource-based theory) provides only a useful guide to identifying important resources and relationships.  The current study argues that organization image is one such resource.  The ability of this resource is to enhance an organization competitive advantage.  Furthermore, the tacitness, complexity, and specificity characterized by organization image can make this advantage sustainable

    Nano-Size Layered Manganese-Calcium Oxide as an Efficient and Biomimetic Catalyst for Water Oxidation Under Acidic Conditions: Comparable To Platinum

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    Inspired by Nature's catalyst, a nano-size layered manganese-calcium oxide showed a low overvoltage for water oxidation in acidic solutions, which is comparable to platinum.Institute for Advanced Studies in Basic Sciences and the National Elite FoundationUS Department of Energy, Office of Basic Energy Sciences, Division of Chemical, Geochemical and Biological Sciences DE-FG02-86ER13622, DE-FG0209ER16119Russian Foundation for Basic Research 11-04-01389a, 12-0492101a, 13-04-92711aMolecular and Cell Biology Programs of the Russian Academy of SciencesCenter for Electrochemistr

    Quantitative Imaging of Single, Unstained Viruses with Coherent X-rays

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    Since Perutz, Kendrew and colleagues unveiled the structure of hemoglobin and myoglobin based on X-ray diffraction analysis in the 1950s, X-ray crystallography has become the primary methodology used to determine the 3D structure of macromolecules. However, biological specimens such as cells, organelles, viruses and many important macromolecules are difficult or impossible to crystallize, and hence their structures are not accessible by crystallography. Here we report, for the first time, the recording and reconstruction of X-ray diffraction patterns from single, unstained viruses. The structure of the viral capsid inside a virion was visualized. This work opens the door for quantitative X-ray imaging of a broad range of specimens from protein machineries, viruses and organelles to whole cells. Moreover, our experiment is directly transferable to the use of X-ray free electron lasers, and represents a major experimental milestone towards the X-ray imaging of single macromolecules.Comment: 16 pages, 5 figure

    Low-Cost Smart Antenna Using Active Frequency Selective Surfaces

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    Smart antenna is a key technology for advanced wireless systems and one of the most important features of smart antenna is electronically beam scanning or switching. It is highly desirable to reduce the mass, power consumption and cost of smart antennas, as the traditional phased array is always associated with high cost due to the use of many T/R modules and complicated beamforming network (BFN). This paper presents the University of Kent's recent research progress in the field of low-cost smart antenna design using active frequency selective surfaces (AFSS). Firstly, this paper presents a brief review of AFSS based beam-reconfigurable antenna including several recent designs reported by the authors' group. Then, a new high-gain AFSS antenna design with some preliminary results will be presented. This is design achieves higher gain than the reported AFSS antennas. A detailed list of references is given at the end of this paper

    Removal Of Myeloid Cells From Autologous Leukocytes Used For Chimeric Antigen Receptor (Car) T Cell Manufacturing Improves Final Product Consistency And Yields

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    Early phase clinic trails of T cells genetically engineered to express Chimeric Antigen Receptors (CAR) have been promising. CD19-CAR T cells have been used successfully in a number of clinical trials to treat non-Hodgkin’s lymphoma and acute lymphocytic leukemia (ALL) and clinical trials of GD2-CAR T cells for the treatment of osteosarcoma and neuroblastoma are underway. Most CAR T cell manufacturing protocols make use of autologous peripheral blood mononuclear cell (PBMC) concentrates collected by apheresis, however, the lymphocyte-rich PBMC concentrates are also enriched for monocytes and contain small but variable quantities of red blood cells, platelets and neutrophils and prior to beginning CAR T cell manufacturing the PBMC concentrates are generally enriched for lymphocytes or CD3+ cells. We initially manufactured CD19- and GD2-CAR T cells using autologous PBMC concentrates enriched for T cells by selection with the anti-CD3/CD28 beads. These same anti-CD3/CD28 beads were used to stimulated T cell expansion. While the method was, in general, effective, we found that the quantities of GD2-CAR T cells produced were less than the quantities of CD19 CAR T cells produced. In addition, T cells from some patients failed to expand at all. Further investigation found that the presence of large quantities of monocytes or granulocytes in some PBMC concentrates which was associated with poor in vitro CAR T cell expansion. Myeloid derived suppressor cells (MDSCs) that inhibit T cell proliferation are present in sarcoma and ALL patients. These MDSCs may have a monocyte or neutrophil phenotype. We hypothesized that MDSCs in the PBSC concentrates bound non-specifically to the anti-CD3/CD28 beads and more rigorous enrichment of the starting material for lymphocytes would improve CAR T cell yields and reduce the incidence of manufacturing failures. We modified the T cell enrichment method to include a monocyte-depleting plastic adherence step. This change improved T cell expansion, but it was not completely effective at removing contaminating monocytes and granulocytes and did not completely eliminate manufacturing failures. To provide better depletion of monocytes and granulocytes we subjected PBMC concentrates to counter flow elutriation instrument. We manufactured 8 CD19- and 5 GD2-CAR T cell products from elutriated lymphocytes. All 13 CAR T cell manufacturing procedures yielded sufficient quantities of T cells to meet the dose criteria. The 13 CAR T cell products contained 2,166±1,113 x106 CD3+ cells and 1,064±877 x106 transduced CD3+ T cells. The CAR T cell products manufactured from elutriated lymphocytes yielded significantly more CD3+ cells and transduced CD3+ cells than that of those manufactured from anti-CD3/CD28 bead selected and plastic adherence selected cells. These results show CAR T cell manufacturing yields are greater and more consistent when manufacturing is initiated with lymphocytes that have few contaminating myeloid cells
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