16,043 research outputs found

    Aggregating Dependency Graphs into Voting Agendas in Multi-Issue Elections

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    Many collective decision making problems have a combinatorial structure: the agents involved must decide on multiple issues and their preferences over one issue may depend on the choices adopted for some of the others. Voting is an attractive method for making collective decisions, but conducting a multi-issue election is challenging. On the one hand, requiring agents to vote by expressing their preferences over all combinations of issues is computationally infeasible; on the other, decomposing the problem into several elections on smaller sets of issues can lead to paradoxical outcomes. Any pragmatic method for running a multi-issue election will have to balance these two concerns. We identify and analyse the problem of generating an agenda for a given election, specifying which issues to vote on together in local elections and in which order to schedule those local elections

    Electronic states of elongated PbSe/PbS Core/shell quantum dots

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    The optical characteristics of colloidal quantum dots (QDs) are highly dependent on the physical geometry of the QD (size, shape) as well as composition. These dependencies make such systems attractive for application in novel optical devices, notably for solar cell technology. Empirical electronic structure methods, such as kcenterdotp theory, or empirical pseudopotential theories have successfully reproduced experimentally observed transitions in CdSe and PbSe colloidal QDs. Our approach uses the kcenterdotp method to predict such properties as the electronic structure and dipole transitions of ellipsoidal PbSe/PbS core/shell structure colloidal QDs, as a function of eccentricity. Due to the anisotropy between the longitudinal (z) and transverse (x and y) directions, we present results from elongation along both the x and z directions

    Developing an integrated technology roadmapping process to meet regional technology planning needs: the e-bike pilot study

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    Smart grid is a promising class of new technologies offering many potential benefits for electric utility systems, including possibilities for smart appliances which can communicate with power systems and help to better match supply and demand. Additional services include the ability to\ud better integrate growing supplies of renewable energy and perform a variety of value-added services on the grid. However, a number of challenges exist in order to achieving these benefits.\ud Many utility systems have substantial regulatory structures that make business processes and technology innovation substantially different than in other industries. Due to complex histories regarding regulatory and deregulatory efforts, and due to what some economists consider natural monopoly characteristics in the industry, such regulatory structures are unlikely to change in the immediate future. Therefore, innovation within these industries, including the development of\ud smart grid, will require an understanding of such regulatory and policy frameworks, development of appropriate business models, and adaptation of technologies to fit these emerging requirements. Technology Roadmapping may be a useful method of planning this type of future development within the smart grid sector, but such technology roadmaps would require a high level of integrated thinking regarding technology, business, and regulatory and policy considerations. This research provides an initial examination of the process for creating such a type of integrated technology roadmapping and assessment process. This research proposes to build upon previous research in the Pacific Northwest and create a more robust technology planning process that will allow key variables to be tested and different pathways to be explored

    Simultaneous Embeddability of Two Partitions

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    We study the simultaneous embeddability of a pair of partitions of the same underlying set into disjoint blocks. Each element of the set is mapped to a point in the plane and each block of either of the two partitions is mapped to a region that contains exactly those points that belong to the elements in the block and that is bounded by a simple closed curve. We establish three main classes of simultaneous embeddability (weak, strong, and full embeddability) that differ by increasingly strict well-formedness conditions on how different block regions are allowed to intersect. We show that these simultaneous embeddability classes are closely related to different planarity concepts of hypergraphs. For each embeddability class we give a full characterization. We show that (i) every pair of partitions has a weak simultaneous embedding, (ii) it is NP-complete to decide the existence of a strong simultaneous embedding, and (iii) the existence of a full simultaneous embedding can be tested in linear time.Comment: 17 pages, 7 figures, extended version of a paper to appear at GD 201

    Current Advancements and Strategies in Tissue Engineering for Wound Healing: A Comprehensive Review

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    SIGNIFICANCE: With an aging population leading to an increase in diabetes and associated cutaneous wounds, there is a pressing clinical need to improve wound-healing therapies. RECENT ADVANCES: Tissue engineering approaches for wound healing and skin regeneration have been developed over the past few decades. A review of current literature has identified common themes and strategies that are proving successful within the field: The delivery of cells, mainly mesenchymal stem cells, within scaffolds of the native matrix is one such strategy. We overview these approaches and give insights into mechanisms that aid wound healing in different clinical scenarios. CRITICAL ISSUES: We discuss the importance of the biomimetic niche, and how recapitulating elements of the native microenvironment of cells can help direct cell behavior and fate. FUTURE DIRECTIONS: It is crucial that during the continued development of tissue engineering in wound repair, there is close collaboration between tissue engineers and clinicians to maintain the translational efficacy of this approach

    Improved immunological detection of S pongospora subterranea

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    The genus Spongospora has two members which are important pathogens of vegetables, S. subterranea f.sp. subterranea (Sss) and S. subterranea f.sp. nasturtii (Ssn). The close taxonomic relationship of these formae speciales is based on similar cystosori morphology. The potato disease powdery scab, caused by Sss, is difficult to control. The key control measure is avoidance, aimed at planting clean seed in clean soil. For the development of routine tests for the presence of the pathogen on tubers and in soil, a monoclonal antibody (MAb) was developed using Sss cystosori as immunogen. It detected less than one Sss cystosorus and recognised Sss material from many parts of the world. No cross-reactions with other Plasmodiophoromycetes including Plasmodiophora brassicae, Polymyxa betae, Polymyxa graminis and different Streptomyces species causing common and netted scab of potatoes were observed. A novel tuber sample test method was developed using a kitchen peeling machine. This detected two tubers with one powdery scab lesion each in a sample including eighteen uninfected tubers. When soil samples spiked with cystosori were tested with the MAb, different Sss infestation levels could be discriminated. Ssn cystosori gave absorbance values in ELISA as high as Sss cystosori, whereas fresh crook roots of watercress containing Ssnzoosporangia and plasmodia or mud from an Ssninfected watercress bed gave low absorbance values or no reaction. The potential of these findings for the development of a disease control management are discusse

    Exploring the sectoral level impacts and absolute emission changes of using alternative fuels in international shipping

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    The shipping sector is required to reduce fuel sulphur content to 0.1% in Emission Control Areas by 2015 and to 0.5% globally by 2020. At the same time there is regulation and a need to address NOx and PM emissions at a localised level and increasing pressure to address the sector’s rising CO2 emissions, which is a major contributor to global climate change. A measure to address these challenges is to switch from the use of heavy fuel oil to alternative fuels that are able to address local pollutants and carbon emissions in parallel. This paper aims to explore the wider impacts of decisions on the choice of fuel undertaken at ship level. This is achieved by incorporating into shipping tool deployed in this study (GloTraM) the upstream and operational emissions for a range of alternative fuels, and test running them with a series of future scenarios. Key research questions include: (1) what are the total CO2 emissions when GloTraM is run with upstream emission factors added?; (2) what impact do these emissions have on the amount/type of fuels used in the sector?; (3) What are the nonGHG emissions and how significant are they compared to CO2 emissions? A life cycle approach is used to generate the upstream, i.e. well-to-tank emissions, accounting for the emissions associated with the processes used to grow and/or manufacture, distribute and dispose of an alternative fuel. The functional unit is tonne of CO2 per tonne of fuel delivered (to the vessel). These emissions are then incorporated alongside the operational emissions, which have been taken from the IMO’s 3rd GHG study. The results of the study provide a better understanding of the magnitude of total emissions from international shipping and the wider system level implications of fuel switching decisions
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