379 research outputs found

    Speed Partitioning for Indexing Moving Objects

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    Indexing moving objects has been extensively studied in the past decades. Moving objects, such as vehicles and mobile device users, usually exhibit some patterns on their velocities, which can be utilized for velocity-based partitioning to improve performance of the indexes. Existing velocity-based partitioning techniques rely on some kinds of heuristics rather than analytically calculate the optimal solution. In this paper, we propose a novel speed partitioning technique based on a formal analysis over speed values of the moving objects. We first show that speed partitioning will significantly reduce the search space expansion which has direct impacts on query performance of the indexes. Next we formulate the optimal speed partitioning problem based on search space expansion analysis and then compute the optimal solution using dynamic programming. We then build the partitioned indexing system where queries are duplicated and processed in each index partition. Extensive experiments demonstrate that our method dramatically improves the performance of indexes for moving objects and outperforms other state-of-the-art velocity-based partitioning approaches

    The phylogenetically-related pattern recognition receptors EFR and XA21 recruit similar immune signaling components in monocots and dicots

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    During plant immunity, surface-localized pattern recognition receptors (PRRs) recognize pathogen-associated molecular patterns (PAMPs). The transfer of PRRs between plant species is a promising strategy for engineering broad-spectrum disease resistance. Thus, there is a great interest in understanding the mechanisms of PRR-mediated resistance across different plant species. Two well-characterized plant PRRs are the leucine-rich repeat receptor kinases (LRR-RKs) EFR and XA21 from Arabidopsis thaliana (Arabidopsis) and rice, respectively. Interestingly, despite being evolutionary distant, EFR and XA21 are phylogenetically closely related and are both members of the sub-family XII of LRR-RKs that contains numerous potential PRRs. Here, we compared the ability of these related PRRs to engage immune signaling across the monocots-dicots taxonomic divide. Using chimera between Arabidopsis EFR and rice XA21, we show that the kinase domain of the rice XA21 is functional in triggering elf18-induced signaling and quantitative immunity to the bacteria Pseudomonas syringae pv. tomato (Pto) DC3000 and Agrobacterium tumefaciens in Arabidopsis. Furthermore, the EFR:XA21 chimera associates dynamically in a ligand-dependent manner with known components of the EFR complex. Conversely, EFR associates with Arabidopsis orthologues of rice XA21-interacting proteins, which appear to be involved in EFR-mediated signaling and immunity in Arabidopsis. Our work indicates the overall functional conservation of immune components acting downstream of distinct LRR-RK-type PRRs between monocots and dicots

    Polysaccharides from the root of Angelica sinensis promotes hematopoiesis and thrombopoiesis through the PI3K/AKT pathway

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    <p>Abstract</p> <p>Background</p> <p>Dozens of Traditional Chinese Medicine (TCM) formulas have been used for promotion of "blood production" for centuries, and we are interested in developing novel thrombopoietic medicines from these TCMs. Our previous studies have demonstrated the hematopoietic effects of DangGui BuXue Tong (DBT), a formula composed of <it>Radix Angelicae Sinensis </it>and <it>Radix Astragali </it>in animal and cellular models. As a step further to identify and characterize the active chemical components of DBT, we tested the hematopoietic and particularly, thrombopoietic effects of polysaccharide-enriched fractions from the root of <it>Radix Angelicae Sinensis </it>(APS) in this study.</p> <p>Methods</p> <p>A myelosuppression mouse model was treated with APS (10 mg/kg/day). Peripheral blood cells from APS, thrombopoietin and vehicle-treated samples were then counted at different time-points. Using the colony-forming unit (CFU) assays, we determined the effects of APS on the proliferation and differentiation of hematopoietic stem/progenitor cells and megakaryocytic lineages. Using a megakaryocytic cell line M-07e as model, we analyzed the cellular apoptosis progression with and without APS treatment by Annexin V, Mitochondrial Membrane Potential and Caspase 3 assays. Last, the anti-apoptotic effect of APS on cells treated with Ly294002, a Phosphatidylinositol 3-Kinse inhibitor (PI3K) was also tested.</p> <p>Results</p> <p>In animal models, APS significantly enhanced not only the recovery of platelets, other blood cells and their progenitor cells, but also the formation of Colony Forming Unit (CFU). In M-07e cells, we observed the anti-apoptotic effect of APS. Treatment by Ly294002 alone increased the percentage of cells undergoing apoptosis. However, addition of APS to Ly294002-treated cells significantly reduced the percentage of cells undergoing apoptosis.</p> <p>Conclusions</p> <p>APS promotes hematopoiesis and thrombopoiesis in the mouse model. This effect likely resulted from the anti-apoptosis activity of APS and is likely to involve the PI3K/AKT pathway.</p

    First-time mothers’ experiences of pregnancy and birth following assisted reproductive technology treatment in Taiwan

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    Background Assisted Reproductive Technology (ART) treatment tends to involve significant physical and emotional commitments that can impact maternal, infant and family health and well-being. An in-depth understanding of experiences is necessary to provide adequate support for women and their families during pregnancy and transition to parenthood following ART treatment. The aim of this study was to explore first-time mothers’ experiences of pregnancy and transition to parenthood following successful ART treatment in Taiwan. Method Twelve first-time mothers who conceived and gave live birth using ART treatment were purposively selected from a fertility centre in Taipei, Taiwan. Women’s experiences in pregnancy and in their transition to motherhood were explored using semi-structured in-depth interviews. All interviews were recorded, transcribed, and analysed using the Colaizzi strategy. Results The mothers’ accounts reflected three main themes: ‘being different from mothers who became pregnant naturally’; ‘ensuring health and safety of the foetus’; and ‘welcoming new lives with excitement’. The difference mothers felt about themselves was evident in four subthemes: becoming pregnant after a long wait, feeling vulnerable during pregnancy, relying on family’s assistance and support, and worrying about the impact of ART on health. The theme on ‘ensuring health and safety of the foetus’ encompassed three subthemes: activities to protect the unborn baby, monitoring foetal movement constantly to maintain peace of mind, and receiving foetal reduction for the sake of the pregnancy. Narratives around ‘welcoming new lives with excitement’ reflected four subthemes: overcoming hardship for worthwhile results, realising one’s life and dreams, proving to be fertile enough to give birth, and return to normal life track. Conclusion Findings indicate the need for educational and psychosocial interventions to support women and their families physically and psychologically during ART treatment. The stigma related to infertility and the psychosocial support from family are aspects to consider while planning intervention programmes

    Efficient allocations in economies with asymmetric information when the realized frequency of types is common knowledge

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    We consider a general economy, where agents have private information about their types. Types can be multidimensional and potentially interdependent. We show that, if the realized frequency of types (the exact number of agents for each type) is common knowledge, then a mechanism exists, which is consistent with truthful revelation of private information and which implements first-best allocations of resources as the unique equilibrium. The result requires the single-crossing property on utility functions and the anonymity of the Pareto correspondence

    Fire detection from social media images by means of instance-based learning

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    Social media can provide valuable information to support decision making in crisis management, such as in accidents, explosions, and fires. However, much of the data from social media are images, which are uploaded at a rate that makes it impossible for human beings to analyze them. To cope with that problem, we design and implement a database-driven architecture for fast and accurate fire detection named FFireDt. The design of FFireDt uses the instance-based learning through indexed similarity queries expressed as an extension of the relational Structured Query Language. Our contributions are: (i) the design of the Fast-Fire Detection (FFireDt), which achieves efficiency and efficacy rates that rival to the state-of-the-art techniques; (ii) the sound evaluation of 36 image descriptors, for the task of image classification in social media; (iii) the evaluation of content-based indexing with respect to the construction of instance-based classification systems; and (iv) the curation of a ground-truth annotated dataset of fire images from social media. Using real data from Flickr, the experiments showed that system FFireDt was able to achieve a precision for fire detection comparable to that of human annotators. Our results are promising for the engineering of systems to monitor images uploaded to social media services.FAPESPCNPqCAPESSTIC-AmSudRESCUER project, funded by the European Commission (Grant: 614154) and by the CNPq/MCTI (Grant: 490084/2013-3)International Conference on Enterprise Information Systems - ICEIS (17. 2015 Barcelona
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