Factors influencing the distribution of charge in polar nanocrystals

We perform first-principles calculations of wurtzite GaAs nanorods to explore the factors determining charge distributions in polar nanostructures. We show that both the direction and magnitude of the dipole moment $\mathbf{d}$ of a nanorod, and its electic field, depend sensitively on how its surfaces are terminated and do not depend strongly on the spontaneous polarization of the underlying lattice. We identify two physical mechanisms by which $\mathbf{d}$ is controlled by the surface termination, and we show that the excess charge on the nanorod ends is not strongly localized. We discuss the implications of these results for tuning nanocrystal properties, and for their growth and assembly.Comment: Accepted for publication in Phys. Rev. B Rapid Communication

Convergence and Heterogeneity in Euro Based Economies:Stability and Dynamics

Cluster analysis is used to explore the performance of key macroeconomic variables in European countries that share the euro, from the inception of the currency in 2002 through to 2013. An original applied statistical approach searches for a pattern synthesis across a matrix of macroeconomic data to examine if there is evidence for country clusters and whether there is convergence of the cluster patterns over time. A number of different clusters appear and these change over time as the economies of the member states dynamically interact. This includes some new countries joining the currency during the period of examination. As found in previous research, Southern European countries tend to remain separate from other countries. The new methods used, however, add to an understanding of some differences between Southern European countries, in addition to replicating their broad similarities. Hypotheses are formed about the country clusters existing in 2002, 2006 and 2013, at key points in time of the euro integration process. These hypotheses are tested using the rigour of a bivariate analysis and the multivariate method of Qualitative Comparative Analysis (QCA). The results confirm the hypotheses of cluster memberships in all three periods. The confirmation analysis provides evidence about which variables are most influencing cluster memberships at each time point. In 2002 and 2006, differences between countries are influenced by their different Harmonised Index of Consumer Prices (HICP) and labour productivity scores. In 2013, after the crisis, there is a noticeable change. Long term interest rates and gross government debt become key determinants of differences, in addition to the continuing influence of labour productivity. The paper concludes that in the last decade the convergence of countries sharing the euro has been limited, by the joining of new countries and the circumstances of the global economic crisis. The financial crisis has driven divergences from pre-existing integration. Country convergence needs to be understood as a dynamic and multivariate concept. This is a significant development of convergence theory and is an addition to how the concept has been understood previously

Anion receptor chemistry: highlights from 2011 and 2012

This review covers advances in anion complexation in the years 2011 and 2012. The review covers both organic and inorganic systems and also highlights the applications to which anion receptors can be applied such as self-assembly and molecular architecture, sensing, catalysis and anion transport

Understanding the influence of values in complex systems-based approaches to public policy and management

Attempts to apply complexity theory to public management have focused on the dynamic systems environment. This accepts that in public systems there are many externalities, unstable processes, and indeterminate outcomes. Resulting practices have focused on system resilience, patterns of practice, and adaptability. This article revisits complex systems and theorizes public organizations as dynamic systems of public values. The rigour of such an original approach requires a juxtaposition of values with complexity theory. Theorizing value systems in public policy implies they are a key element of complexity and provides a significant development for understanding stable and unstable dynamics in public organizations

The Complexity and Instability of Policy Conditionality and Transfer: IMF Interventions in the Political Economy of South America.

International Monetary Fund (IMF) interventions have evolved in the last sixty years based on the predominant orthodoxy in world political economy with a focus in recent decades on encouraging liberal market conditions to secure inward investment and capital flows. This has resulted in a dominant model of policy conditions and transfer, but with a debate about the contextual relevance. This paper uses an innovative approach to longitudinal research, called Dynamic Pattern Synthesis, to compare the economic performance of South American nations between 2000-2015. The results from using this method illustrates multifinality in the IMF outcome of encouraging foreign direct investment. A complex configuration of influences on this outcome are evidenced. Complexity theory is used to explain the results, with the continent defined as a complex system that does not respond to simple causal policy mechanisms, but rather displays different patterns of political and economic influence in the context of global market instability. Different foreign direct investment configurations result, and these illustrate that international monetary and policy interventions need to be contextual and cannot make simplistic and universal assumptions about policy problems and their mechanistic solutions.