17,523 research outputs found

    Toward a Modern Macroeconomic Model Usable for Policy Analysis

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    This paper presents a macroeconomic model that is both a completely specified dynamic general equilibrium model and a probabilistic model for time series data. We view the model as a potential competitor to existing ISLM-based models that continue to be used for actual policy analysis. Our approach is also an alternative to recent efforts to calibrate real business cycle models. In contrast to these existing models, the one we present embodies all the following important characteristics: i) It generates a complete multivariate stochastic process model for the data it aims to explain, and the full specification is used in the maximum likelihood estimation of the model; ii) It integrates modeling of nominal variables -- money stock, price level, wage level, and nominal interest rate -- with modeling real variables; iii) It contains a Keynesian investment function, breaking the tight relationship of the return on investment with the capital-output ratio; iv) It treats both monetary and fiscal policy explicitly; v) It is based on dynamic optimizing behavior of the private agents in the model. Flexible-price and sticky-price versions of the model are estimated and their fits are evaluated relative to a naive model of no-change in the variables and to an unrestricted VAR. The paper displays the model's implications for the dynamic responses to structural shocks, including policy shocks, and evaluates the relative importance of various shocks for determining economic fluctuations.

    Femtosecond probing of bimolecular reactions: The collision complex

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    Progress has been made in probing the femtosecond dynamics of transition states of chemical reactions.(1) The "half-collision" case of unimolecular reactions has been experimentally investigated for a number of systems and much theoretical work has already been developed.(2) For bimolecular reactions, the case of full collision, the zero of time is a problem which makes the femtosecond temporal resolution of the dynamics a difficult task

    Co-universal algebras associated to product systems, and gauge-invariant uniqueness theorems

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    Let X be a product system over a quasi-lattice ordered group. Under mild hypotheses, we associate to X a C*-algebra which is co-universal for injective Nica covariant Toeplitz representations of X which preserve the gauge coaction. Under appropriate amenability criteria, this co-universal C*-algebra coincides with the Cuntz-Nica-Pimsner algebra introduced by Sims and Yeend. We prove two key uniqueness theorems, and indicate how to use our theorems to realise a number of reduced crossed products as instances of our co-universal algebras. In each case, it is an easy corollary that the Cuntz-Nica-Pimsner algebra is isomorphic to the corresponding full crossed product.Comment: 40 pages, 2 figures; v2: minor changes to the introduction, references added and update

    Short-Chained Oligo(Ethylene Oxide)-Functionalized Gold Nanoparticles: Realization Of Significant Protein Resistance

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    Protein corona formed on nanomaterial surfaces play an important role in the bioavailability and cellular uptake of nanomaterials. Modification of surfaces with oligoethylene glycols (OEG) are a common way to improve the resistivity of nanomaterials to protein adsorption. Short-chain ethylene oxide (EO) oligomers have been shown to improve the protein resistance of planar Au surfaces. We describe the application of these EO oligomers for improved protein resistance of 30 nm spherical gold nanoparticles (AuNPs). Functionalized AuNPs were characterized using UV-Vis spectroscopy, dynamic light scattering (DLS), and zeta potential measurements. Capillary electrophoresis (CE) was used for separation and quantitation of AuNPs and AuNP-protein mixtures. Specifically, nonequilibrium capillary electrophoresis of equilibrium mixtures (NECEEM) was employed for the determination of equilibrium and rate constants for binding between citrate-stabilized AuNPs and two model proteins, lysozyme and fibrinogen. Semi-quantitative CE analysis was carried out for mixtures of EO-functionalized AuNPs and proteins, and results demonstrated a 2.5-fold to 10-fold increase in protein binding resistance to lysozyme depending on the AuNP surface functionalization and a 15-fold increase in protein binding resistance to fibrinogen for both EO oligomers examined in this study

    Absence of reflection as a function of the coupling constant

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    We consider solutions of the one-dimensional equation u+(Q+λV)u=0-u'' +(Q+ \lambda V) u = 0 where Q:RRQ: \mathbb{R} \to \mathbb{R} is locally integrable, V:RRV : \mathbb{R} \to \mathbb{R} is integrable with supp(V)[0,1](V) \subset [0,1], and λR\lambda \in \mathbb{R} is a coupling constant. Given a family of solutions {uλ}λR\{u_{\lambda} \}_{\lambda \in \mathbb{R}} which satisfy uλ(x)=u0(x)u_{\lambda}(x) = u_0(x) for all x<0x<0, we prove that the zeros of b(λ):=W[u0,uλ]b(\lambda) := W[u_0, u_{\lambda}], the Wronskian of u0u_0 and uλu_{\lambda}, form a discrete set unless V0V \equiv 0. Setting Q(x):=EQ(x) := -E, one sees that a particular consequence of this result may be stated as: if the fixed energy scattering experiment u+λVu=Eu-u'' + \lambda V u = Eu gives rise to a reflection coefficient which vanishes on a set of couplings with an accumulation point, then V0V \equiv 0.Comment: To appear in Journal of Mathematical Physic

    Propagation of Correlations in Quantum Lattice Systems

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    We provide a simple proof of the Lieb-Robinson bound and use it to prove the existence of the dynamics for interactions with polynomial decay. We then use our results to demonstrate that there is an upper bound on the rate at which correlations between observables with separated support can accumulate as a consequence of the dynamics.Comment: 10 page

    Psychological impact of identifying character strengths in people with psychosis

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    A one group pre-post test design investigated the impact of identifying character strengths using the Values In Action Inventory of Strengths (VIA-IS) with individuals with early psychosis (N = 29). Post-test improvements in positive affect and cognitive performance were observed. Neither self-esteem nor self-efficacy improved. The technique appears feasible for use within early intervention services. Adverse consequences should be monitored and additional components considered to enhance benefits
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