7,832 research outputs found

    On the Estimation of Euler Equations in the Presence of a Potential Regime Shift

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    The concept of a peso problem is formalized in terms of a linear Euler equation and a nonlinear marginal model describing the dynamics of the exogenous driving process. It is shown that, using a threshold autoregressive model as a marginal model, it is possible to produce time-varying peso premia. A Monte Carlo method and a method based on the numerical solution of integral equations are considered as tools for computing conditional future expectations in the marginal model. A Monte Carlo study illustrates the poor performance of the generalized method of moment (GMM) estimator in small and even relatively large samples. The poor performance is particularly acute in the presence of a peso problem but is also serious in the simple linear case.peso problem; Euler equations; GMM; threshold autoregressive models

    Copper-Catalyzed Regioselective Boracarboxylation of Vinyl Arenes: Catalytic Efficiency and Synthetic Utility

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    Hetero(element) carboxylation is an appealing transformation that involves the installation of CO2 and another hetero(element) in one step. This transition metal-catalyzed one-pot synthesis provides a route to achieve highly functionalized carboxylic acid products with an abundant and cheap C1 feedstock. This difunctionalization also avoids the use of reactive metal hydride species, which is a prominent limitation of hydrocarboxylation chemistry. A copper-catalyzed regioselective boracarboxylation of vinyl arenes has been developed to access pharmaceutically relevant β-boryl-α-aryl propionic acid products. One drawback of this reaction is the necessity for high catalyst loading to achieve catalytic turnover. To circumvent this issue, the reduction of catalyst loading by addition of a secondary phosphine ligand was examined to access previously reported substrates and an expanded scope for this transformation. Trends in reactivity and preliminary experiments to determine the role of exogenous phosphine in the catalytic system will be described. The synthetic utility of the boracarboxylated products was investigated through a contemporary carbon-boron bond transformation to afford fluorinated products. The reactivity and scope of a deboronofluorination pathway will be presented, along with mechanistic investigation. The synthetic utility of boracarboxylated products to form new carbon-carbon bonds through cross-coupling afforded 2,3-diarylpropionic acids. This synthetic pathway will allow for chemoselectivity that is not observed through traditional pathways, such as the hydrocarboxylation of stilbenes

    UNCTAD's World Investment Reports 1991-2015: 25 years of narratives justifying and balancing foreign investor rights

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    This article examines an influential narrative of foreign investor rights and the international investment regime. It draws on twenty-five of the World Investment Reports (WIRs) issued by the United Nations Conference on Trade and Development (1991–2015). It argues that the justifications provided by these reports have contributed to shaping a global commodity conception of property. These WIRs describe foreign investor rights following a narrative of wealth maximisation by transnational corporations (TNCs), and focus on a TNC-assisted restructuring of host states and local communities. Since the mid-2000s, these reports have balanced this narrative because of the increasing consensus that international investment treaties unduly constrain regulatory space. Ultimately, however, this article shows that the recent WIRs promote an approach to public regulation that is not inconsistent with a global commodity conception of property

    The Emerging Global Right to Investment: Understanding the reasoning behind foreign investor rights

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    The international investment regime is probably the most controversial area of international law today. This article argues that looking at the interpretation of foreign investor rights can help us to better understand this regime and the challenges it poses to states and local actors. Relying on property and contract law theory, this article shows that the arbitral interpretation of foreign investor rights privileges wealth maximization over propriety. This leads arbitrators to draw on particular theories of property and contractual reliance. The analysis of these interpretative moves brings to the front crucial normative and distributive implications of the international investment regime

    Applied research by design: an experimental collaborative and interdisciplinary design charrette

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    This article reports on one experimental case of interdisciplinary collaboration on a design and planning exercise across several scales – local through urban to regional – and sectors – private, public, scholarly, and interest groups. The case is a collaborative and interdisciplinary design charrette on sustainable urbanism for envisioning the future of the Greater Metropolitan Area of Florence in Italy. The experiment entailed the attempt to integrate complex urban conditions via the design charrette in order to create more healthy and sustainable cities. This collaborative work shows how conditions that are at times not addressed comprehensively nor holistically can be combined through doing applied research by design; where design is understood as a process of discovery and creation that results in synthesis. The article details the methodology applied, and provides an initial assessment on the process that the charrette employed. Moreover, it highlights some professional and policy implications of the effort. Finally, it provides a provisional assessment on learning outcomes and addresses opportunities to improve future exercises of this nature

    Simulation of UHE muons propagation for GEANT3

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    A simulation package for the transport of high energy muons has been developed. It has been conceived to replace the muon propagation software modules implemented in the detector simulation program GEANT3. Here we discuss the results achieved with our package and we check the agreement with numerical calculations up to 10**8 GeV.Comment: 21 pages, 6 figures, 1 Table. AMSTeX document, acknowledgments adde

    Instantaneous cell migration velocity may be ill-defined

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    Cell crawling is critical to biological development, homeostasis and disease. In many cases, cell trajectories are quasi-random-walk. In vitro assays on flat surfaces often described such quasi-random-walk cell trajectories as approximations to a solution of a Langevin process. However, experiments show quasi-diffusive behavior at small timescales, indicating that instantaneous velocity and velocity autocorrelations are not well-defined. We propose to characterize mean-squared cell displacement using a modified F\"urth equation with three temporal and spatial regimes: short- and long-time/range diffusion and intermediate time/range ballistic motion. This analysis collapses mean-squared displacements of previously published experimental data onto a single-parameter family of curves, allowing direct comparison between movement in different cell types, and between experiments and numerical simulations. Our method also show that robust cell-motility quantification requires an experiment with a maximum interval between images of a few percent of the cell-motion persistence time or less, and a duration of a few orders-of-magnitude longer than the cell-motion persistence time or more.Comment: 5 pages, plus Supplemental materia
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