968 research outputs found

    Entangling Alliances: Presidents and Strategic Issue Linkage in International Negotiations

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    Abstract Why are issues linked in international negotiations? I propose one mechanism by which executives can use agenda control to both force and block linkage in international negotiations to their advantage. In so doing, I improve on Putna

    Expressive political behaviour : foundations, scope and implications

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    A growing literature has focused attention on ‘expressive’ rather than ‘instrumental’ behaviour in political settings, particularly voting. A common criticism of the expressive idea is that it is ad hoc and lacks both predictive and normative bite. No clear definition of expressive behaviour has gained wide acceptance yet, and no detailed understanding of the range of foundations of specific expressive motivations has emerged. This article provides a foundational discussion and definition of expressive behaviour accounting for a range of factors. The content of expressive choice – distinguishing between identity-based, moral and social cases – is discussed and related to the specific theories of expressive choice in the literature. There is also a discussion of the normative and institutional implications of expressive behaviour

    A note on a third order curvature invariant in static spacetimes

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    We consider here the third order curvature invariant I=RΌΜρσ;ÎŽRΌΜρσ;ÎŽI=R_{\mu\nu\rho\sigma;\delta}R^{\mu\nu\rho\sigma;\delta} in static spacetimes M=R×Σ{\cal M}=R\times\Sigma for which ÎŁ\Sigma is conformally flat. We evaluate explicitly the invariant for the NN-dimensional Majumdar-Papapetrou multi black-holes solution, confirming that II does indeed vanish on the event horizons of such black-holes. Our calculations show, however, that solely the vanishing of II is not sufficient to locate an event horizon in non-spherically symmetric spacetimes. We discuss also some tidal effects associated to the invariant II.Comment: 5 pages, 3 figures. Extra material available at http://vigo.ime.unicamp.br/in

    Searching for the Kuhnian moment : the Black-Scholes-Merton formula and the evolution of modern finance theory

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    The Black-Scholes-Merton formula has been put to widespread use by options traders because it provides a means of calculating the theoretically 'correct' price of stock options. Traders can therefore see whether the market price of stock options undervalues or overvalues them compared with their hypothetical Black-Scholes-Merton price, before choosing to buy or sell options accordingly. As a consequence of this close relationship between options pricing theory and options pricing practice, a strong performativity loop was activated, whereby market prices quickly converged on the hypothetical Black-Scholes-Merton prices following the dissemination of the formula. The theory has therefore had significant real-world effects, but how should we characterize the initial instinct to derive the theory from a philosophy of science perspective? The two books under review suggest that a Kuhnian reading of the advancement of scientific knowledge might well be the most appropriate. But, on closer inspection, it becomes clear that the publication of the Black-Scholes-Merton formula should not be seen as a Kuhnian moment with paradigm-shaping attributes. It is shown that, at most, the formula acts as an important exemplar which, via its use in the training of options pricing theorists and options pricing practitioners, reinforces the entrenchment of finance theory within the orthodox economics worldview

    New reactivity at the silicon bridge in sila[1]ferrocenophanes

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    Two new types of reactivity involving silicon-bridged [1]ferrocenophanes are described.</p

    Main-chain metallopolymers at the static–dynamic boundary based on nickelocene

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    Interactions between metal ions and ligands in metal-containing polymers involve two bonding extremes: persistent covalent bonding, in which the polymers are essentially static in nature, or labile coordination bonding, which leads to dynamic supramolecular materials. Main-chain polymetallocenes based on ferrocene and cobaltocene fall into the former category because of the presence of strong metal–cyclopentadienyl bonds. Herein, we describe a main-chain polynickelocene—formed by ring-opening polymerization of a moderately strained [3]nickelocenophane monomer—that can be switched between static and dynamic states because of the relatively weak nickel–cyclopentadienyl ligand interactions. This is illustrated by the observation that, at a low concentration or at an elevated temperature in a coordinating or polar solvent, depolymerization of the polynickelocene occurs. A study of this dynamic polymer–monomer equilibrium by 1H NMR spectroscopy allowed the determination of the associated thermodynamic parameters. Microrheology data, however, indicated that under similar conditions the polynickelocene is considered to be static on the shorter rheological timescale

    Instances and connectors : issues for a second generation process language

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    This work is supported by UK EPSRC grants GR/L34433 and GR/L32699Over the past decade a variety of process languages have been defined, used and evaluated. It is now possible to consider second generation languages based on this experience. Rather than develop a second generation wish list this position paper explores two issues: instances and connectors. Instances relate to the relationship between a process model as a description and the, possibly multiple, enacting instances which are created from it. Connectors refers to the issue of concurrency control and achieving a higher level of abstraction in how parts of a model interact. We believe that these issues are key to developing systems which can effectively support business processes, and that they have not received sufficient attention within the process modelling community. Through exploring these issues we also illustrate our approach to designing a second generation process language.Postprin

    Chiral Transmission to Cationic Polycobaltocenes over Multiple Length Scales Using Anionic Surfactants

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    International audienceChiral polymers are ubiquitous in nature, and the self-assembly of chiral materials is a field of widespread interest. In this paper, we describe the formation of chiral metallopolymers based on poly(cobaltoceniumethylene) ([PCE] ), which have been prepared through oxidation of poly(cobaltocenylethylene) (PCE) in the presence of enantiopure N-acyl-amino-acid-derived anionic surfactants, such as N-palmitoyl-l-alanine (C-l-Ala) and N-palmitoyl-d-alanine (C-d-Ala). It is postulated that the resulting metallopolymer complexes [PCE][C-l/d-Ala] contain close ionic contacts, and exhibit chirality through the axially chiral ethylenic CH-CH bridges, leading to interaction of the chromophoric [CoCp] units through chiral space. The steric influence of the long palmitoyl (C) surfactant tail is key for the transmission of chirality to the polymer, and results in a brushlike amphiphilic macromolecular structure that also affords solubility in polar organic solvents (e.g., EtOH, THF). Upon dialysis of these solutions into water, the hydrophobic palmitoyl surfactant substituents aggregate and the complex assembles into superhelical ribbons with identifiable "handedness", indicating the transmission of chirality from the molecular surfactant to the micrometer length scale, via the macromolecular complex

    Defining and unpacking the core concepts of pharmacology education

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    Pharmacology education currently lacks a research-based consensus on which core concepts all graduates should know and understand, as well as a valid and reliable means to assess core conceptual learning. The Core Concepts in Pharmacology Expert Group (CC-PEG) from Australia and New Zealand recently identified a set of core concepts of pharmacology education as a first step toward developing a concept inventory—a valid and reliable tool to assess learner attainment of concepts. In the current study, CC-PEG used established methodologies to define each concept and then unpack its key components. Expert working groups of three to seven educators were formed to unpack concepts within specific conceptual groupings: what the body does to the drug (pharmacokinetics); what the drug does to the body (pharmacodynamics); and system integration and modification of drug–response. First, a one-sentence definition was developed for each core concept. Next, sub-concepts were established for each core concept. These twenty core concepts, along with their respective definitions and sub-concepts, can provide pharmacology educators with a resource to guide the development of new curricula and the evaluation of existing curricula. The unpacking and articulation of these core concepts will also inform the development of a pharmacology concept inventory. We anticipate that these resources will advance further collaboration across the international pharmacology education community to improve curricula, teaching, assessment, and learning.Marina Santiago, Elizabeth A. Davis, Tina Hinton, Thomas A. Angelo, Alison Shield, Anna-Marie Babey, Barbara Kemp-Harper, Gregg Maynard, Hesham S. Al-Sallami, Ian F. Musgrave, Lynette B. Fernandes, Suong N. T. Ngo, Arthur Christopoulos, Paul J. Whit
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