1,671 research outputs found

    Factorizations of Matrices Over Projective-free Rings

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    An element of a ring RR is called strongly J#J^{\#}-clean provided that it can be written as the sum of an idempotent and an element in J#(R)J^{\#}(R) that commute. We characterize, in this article, the strongly J#J^{\#}-cleanness of matrices over projective-free rings. These extend many known results on strongly clean matrices over commutative local rings

    Developing an Unnatural Amino Acid-Specific Aminoacyl tRNA Synthetase

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    Unnatural Amino Acids (UAAs), amino acids not present in the human genetic code, have been synthesized to have a broad range of useful properties, in this case, as metal-binders which could have drug delivery applications. In order for the cell to place a UAA into the protein, two components, a unique aminoacyl tRNA synthetase and a corresponding tRNA must be present. If an amino acid is successfully charged to the tRNA, a stop codon is suppressed and a functional protein is built with the UAA at the mutation site. Such a tRNA molecule has previously been developed, as well as many synthetases specific to UAAs. In this work, the range of UAAs which can be incorporated into proteins using the E. coli’s own machinery is expanded by the development of a novel aminoacyl tRNA synthetase. By making a library of synthetase-coding plasmid variants and performing positive and negative screenings, the binding pocket of the synthetase can be modified for specificity to a UAA while not allowing the tRNA to be charged with a natural amino acid. In this work, we are attempting to evolve new tRNA synthetases for the incorporation of metal-binding amino acids by developing the plasmid library and a screening system to find synthetase variants meeting these criteria

    Interactions with Frontiers of Financial Economic — A Research Agenda for Real Estate Finance

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    [Excerpt] Recent years have seen the emergence of substantial scholarly research in real estate finance that uses the methodology and paradigms at the frontiers of financial economics. Agency theory, search theory, and signaling have appeared in several models of real estate finance (see, for example, Damodaran, John, and Liu, 1998; Damodaran and Liu, 1993; Williams, 1993a, 1993b, 1995, 1998). Continuous time-valuation models of financial options, real options, and fixed-income securities and term structure models have also been applied in a number of papers on the pricing of mortgage-backed securities with and without sophisticated prepayment structures (for example, see Dunn and Spatt, 1985, 1986; Grenadier, 1995, 1996; John, Liu, and Radhakrishnan, 1997; Stanton and Wallace, 1998; Williams, 1993a, 1993b, 1997). Paradigms of securitization and optimal design of securities and organizational forms have also made their appearance in recent real estate research (see, for example, DeMarzo and Duffie, 1998; DeMarzo, 1998; Shiller andWeiss, 1998; Damodaran, John, and Liu, 1997). The objective of this special issue is to showcase some of this research in real estate and explore additional paradigms in financial economics that would provide the framework for interesting and innovative real estate research

    The Role of Supreme Audit Institutions in Improving Citizen Participation in Governance

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    Supreme Audit Institutions (SAIs) – key government agencies responsible for auditing how public funds are being spent – have been traditionally seen as insulated and technocratic entities serving other government organizations and having little to do with citizens and broader governance issues. This image has been slowly changing around the world in light of the broader transformations in governments’ roles, SAIs’ own practices, and increased public participation in governance. This article reviews why and how these changes are happening and barriers to the more productive collaboration between SAIs and the public. The article concludes with implications for practitioners and researchers

    The Determinants of Organizational Form Changes: Evidence and Implications from Real Estate

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    We study changes in the real estate industry among organizational forms with varying degrees of restrictiveness and document the associated changes in profitability, free cash flow, debt, dividends, and investment policies. All troubled firms in our sample move to a more flexible organizational structure, with subsequent reductions in dividends, improvements in performance, and increases in asset sales and investments. Healthy firms that move to a tighter structure have larger free cash flows before the change; they increase dividends, reduce free cash flows and improve profitability after the change. We document evidence of tax considerations in organizational changes

    What Motivates Managers? Evidence from Organizational Form Changes

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    We formulate and test several hypotheses on managerial motivation using organizational form changes in the real estate industry. We find that firms that switch to a more restrictive structure have increases in stock value and managerial ownership. Firms moving to a less restrictive structure have larger wealth effects when higher monitoring exists. Higher degree of financial distress and forced CEO replacement at the time of organizational form change are taken to be proxies for higher degree of (creditor) monitoring. The wealth effects are decreasing in the firm’s level of free cash flow at the time of organizational form change

    How Do You Like Me in This: User Embodiment Preferences for Companion Agents

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    We investigate the relationship between the embodiment of an artificial companion and user perception and interaction with it. In a Wizard of Oz study, 42 users interacted with one of two embodiments: a physical robot or a virtual agent on a screen through a role-play of secretarial tasks in an office, with the companion providing essential assistance. Findings showed that participants in both condition groups when given the choice would prefer to interact with the robot companion, mainly for its greater physical or social presence. Subjects also found the robot less annoying and talked to it more naturally. However, this preference for the robotic embodiment is not reflected in the users’ actual rating of the companion or their interaction with it. We reflect on this contradiction and conclude that in a task-based context a user focuses much more on a companion’s behaviour than its embodiment. This underlines the feasibility of our efforts in creating companions that migrate between embodiments while maintaining a consistent identity from the user’s point of view