Bilateral Trade, Openness and Asset Holdings

This paper analyzes the relationship between bilateral trade flows, trade openness, and asset holdings in a three-country stochastic general equilibrium model. The threecountry model set-up enables me to disentangle and separate the effects bilateral trade flows and trade openness have on bilateral portfolio patterns. I find that both factors independently influence bilateral asset holdings. Higher bilateral trade as well as higher trade openness lead to a higher bilateral foreign asset position. Furthermore, the two factors show an interaction effect, where increasing trade openness diminishes the influence of bilateral trade flows on asset holdings. I provide supporting empirical evidence for these theoretical findings using a data set on the geographical composition of international portfolio holdings.International Portfolio Holdings, Bilateral Trade Flows, Trade Openness

Lyapunov functions for linear nonautonomous dynamical equations on time scales

The existence of a Lyapunov function is established following a method of Yoshizawa for the uniform exponential asymptotic stability of the zero solution of a nonautonomous linear dynamical equation on a time scale with uniformly bounded graininess

Quantum simulation of partially distinguishable boson sampling

Boson Sampling is the problem of sampling from the same output probability distribution as a collection of indistinguishable single photons input into a linear interferometer. It has been shown that, subject to certain computational complexity conjectures, in general the problem is difficult to solve classically, motivating optical experiments aimed at demonstrating quantum computational "supremacy". There are a number of challenges faced by such experiments, including the generation of indistinguishable single photons. We provide a quantum circuit that simulates bosonic sampling with arbitrarily distinguishable particles. This makes clear how distinguishabililty leads to decoherence in the standard quantum circuit model, allowing insight to be gained. At the heart of the circuit is the quantum Schur transform, which follows from a representation theoretic approach to the physics of distinguishable particles in first quantisation. The techniques are quite general and have application beyond boson sampling.Comment: 25 pages, 4 figures, 2 algorithms, comments welcom

Collective decisions with interdependent valuations

Many collective decision problems have the common feature that individuals' desired outcomes are correlated but not identical. This paper studies collective decisions with private information about these desired policies. Each agent holds private information which mainly concerns his own bliss point, but this private information also affects all other agents' bliss points. We concentrate on two specific mechanisms, the mean and the median mechanism. We establish existence of two symmetric Bayesian Nash equilibria of the corresponding game and compare the performance of the mechanisms for different degrees of interdependencies. Applications of our framework include the assignment of voting rights in the council of the European Central Bank, the design of decision processes in teams, firms, and international organizations.collective decisions, asymmetric information, interdependent valuations

Fiscal News and Macroeconomic Volatility

This paper analyzes the contribution of anticipated capital and labor tax shocks to business cycle volatility in an estimated New Keynesian DSGE model. While fiscal policy accounts for 12 to 20 percent of output variance at business cycle frequencies, the anticipated component hardly matters for explaining fluctuations of real variables. Anticipated capital tax shocks do explain a sizable part of inflation and interest rate fluctuations, accounting for between 5 and 15 percent of total variance. In line with earlier studies, news shocks in total account for 20 percent of output variance. Further decomposing this news effect, we find that it is mostly driven by stationary TFP and non-stationary investment-specific technology.Anticipated Tax Shocks; Sources of Aggregate Fluctuations; Bayesian Estimation

Living Close to Your Neighbors: The Importance of Both Competition and Facilitation in Plant Communities

Recent work has demonstrated that competition and facilitation likely operate jointly in plant communities, but teasing out the relative role of each has proven difficult. Here we address how competition and facilitation vary with seasonal fluctuations in environmental conditions, and how the effects of these fluctuations change with plant ontogeny. We planted three sizes of pine seedlings (Pinus strobus) into an herbaceous diversity experiment and measured pine growth every two weeks for two growing seasons. Both competition and facilitation occurred at different times of year between pines and their neighbors. Facilitation was important for the smallest pines when environmental conditions were severe. This effect decreased as pines got larger. Competition was stronger than facilitation overall and outweighed facilitative effects at annual time scales. Our data suggest that both competition and the counter‐directional effects of facilitation may be more common and more intense than previously considered

ICOPER Project - Deliverable 4.3 ISURE: Recommendations for extending effective reuse, embodied in the ICOPER CD&R

The purpose of this document is to capture the ideas and recommendations, within and beyond the ICOPER community, concerning the reuse of learning content, including appropriate methodologies as well as established strategies for remixing and repurposing reusable resources. The overall remit of this work focuses on describing the key issues that are related to extending effective reuse embodied in such materials. The objective of this investigation, is to support the reuse of learning content whilst considering how it could be originally created and then adapted with that ‘reuse’ in mind. In these circumstances a survey on effective reuse best practices can often provide an insight into the main challenges and benefits involved in the process of creating, remixing and repurposing what we are now designating as Reusable Learning Content (RLC). Several key issues are analysed in this report: Recommendations for extending effective reuse, building upon those described in the previous related deliverables 4.1 Content Development Methodologies and 4.2 Quality Control and Web 2.0 technologies. The findings of this current survey, however, provide further recommendations and strategies for using and developing this reusable learning content. In the spirit of ‘reuse’, this work also aims to serve as a foundation for the many different stakeholders and users within, and beyond, the ICOPER community who are interested in reusing learning resources. This report analyses a variety of information. Evidence has been gathered from a qualitative survey that has focused on the technical and pedagogical recommendations suggested by a Special Interest Group (SIG) on the most innovative practices with respect to new media content authors (for content authoring or modification) and course designers (for unit creation). This extended community includes a wider collection of OER specialists. This collected evidence, in the form of video and audio interviews, has also been represented as multimedia assets potentially helpful for learning and useful as learning content in the New Media Space (See section 4 for further details). Section 2 of this report introduces the concept of reusable learning content and reusability. Section 3 discusses an application created by the ICOPER community to enhance the opportunities for developing reusable content. Section 4 of this report provides an overview of the methodology used for the qualitative survey. Section 5 presents a summary of thematic findings. Section 6 highlights a list of recommendations for effective reuse of educational content, which were derived from thematic analysis described in Appendix A. Finally, section 7 summarises the key outcomes of this work

Combining knowledge mapping and videoconferencing for open sensemaking communities

The Open Educational Resources (OER) movement has been growing rapidly, opening up new opportunities for widening participation (Willinsky, 2006). OpenLearn is an OER pilot project developed by the UK Open University (OU) [http://www.open.ac.uk/openlearn], and launched in October 2006, supported by the William and Flora Hewlett Foundation. OpenLearn has published 3371 hours in the LearningSPace and 5194 in the LabSpace of OERs designed specifically for distance learning (the OU’s core business), and covers a range of subjects from arts and history to science and nature. There are more than 300 units at all study levels from access to higher education, graduation and postgraduation. Our current work is to investigate how these tools can be used to foster open sensemaking communities (Buckingham Shum, 2005) around the OERs, that is, the interpretative work that must take place around any resource for learning to take place. How can we support this critical activity in an OER context when learners must find and engage with peers themselves, if they do not wish to study alone? This paper introduces the e-learning environment that has been developed after the first year of OpenLearn, focusing on the uses made of two sensemaking support tools, Compendium for knowledge mapping, and FlashMeeting for videoconferencing