The Difference, System and ‘Double-D’ GMM Panel Estimators in the Presence of Structural Breaks

The effects of structural breaks in dynamic panels are more complicated than in time series models as the bias can be either negative or positive. This paper focuses on the effects of mean shifts in otherwise stationary processes within an instrumental variable panel estimation framework. We show the sources of the bias and a Monte Carlo analysis calibrated on United States bank lending data demonstrates the size of the bias for a range of auto-regressive parameters. We also propose additional moment conditions that can be used to reduce the biases caused by shifts in the mean of the data

Dundee Discussion Papers in Economics 265:Estimating United States phillips curves with expectations consistent with the statistical process of inflation

‘Modern’ Phillips curve theories predict inflation is an integrated, or near integrated, process. However, inflation appears bounded above and below indeveloped economies and so cannot be ‘truly’ integrated and more likely stationary around a shifting mean. If agents believe inflation is integrated asin the ‘modern’ theories then they are making systematic errors concerning the statistical process of inflation. An alternative theory of the Phillips curveis developed that is consistent with the ‘true’ statistical process of inflation. It is demonstrated that United States inflation data is consistent with thealternative theory but not with the existing ‘modern’ theories

Regional house price cycles in the UK, 1978-2012: a Markov switching VAR

There is an extensive literature on UK regional house price dynamics, yet empirical work focusing on the duration and magnitude of regional housing cycles has received little attention. This paper employs Markov Switching Vector auto regression (MSVAR) methods to examine UK house price cycles in UK regions at NUTS1 level. The research findings indicate that the regional structure of the UK house market is best described as two large groups of regions with marked differences in the amplitude and duration of the cyclical regimes between the two groups. These differences have implications for the design of both macroeconomic and housing sector policies

The difference, system and ‘Double-D’ GMM panel estimators in the presence of structural breaks

The effects of structural breaks in dynamic panels are more complicated than in time series models as the bias can be either negative or positive. This paper focuses on the effects of mean shifts in otherwise stationary processes within an instrumental variable panel estimation framework. We show the sources of the bias and a Monte Carlo analysis calibrated on United States bank lending data demonstrates the size of the bias for a range auto-regressive parameters. We also propose additional moment conditions that can be used to reduce the biases caused by shifts in the mean of the data

Micellar Aggregates of Gemini Surfactants: Monte Carlo Simulation of a Microscopic Model

We propose a "microscopic" model of gemini surfactants in aqueous solution. Carrying out extensive Monte Carlo simulations, we study the variation of the critical micellar concentration (CMC) of these model gemini surfactants with the variation of the (a) length of the spacer connecting the two hydrophilic heads, (b) length of the hydrophobic tail and (c) the bending rigidity of the hydrocarbon chains forming the spacer and the tail; some of the trends of variation are counter-intuitive but are in excellent agreement with the available experimental results. Our simulations also elucidate the dependence of the shapes of the micellar aggregates and the magnitude of the CMC on the geometrical shape and size of the surfactant molecules and the electrical charge on the hydrophilic heads

Enhancing ecosystem services at urban brownfield sites - What value does contaminated soil have in the built environment?

Urban environments are challenged with a plethora of wicked problems in the face of rapid urbanization and land use change, not least natural capital degradation and widespread land and water contamination. Brownfields, under-used sites with real or perceived contamination, are significant urban and peri-urban land resources which, with well-designed remediation and management strategies can address these concerns. Gentle remediation options (GRO) are scalable nature-based techniques which provide significant opportunities for multi-functionality: managing risks posed by contaminants and at the same time enhance ecosystem services (ES) by improving the soil ecosystem in a low-impact, cost-effective manner. GRO align with an increasing interest in taking a holistic view on soil and land management to protect and improve the soil ecosystem for direct human benefit in the form of ES as well as for its indirect, intrinsic value as a haven for biodiversity. This short review aims to present a synthesis of ideas to raise awareness for urban planners about GRO techniques as nature-based solutions which can promote green infrastructure in the urban environment

A risk management framework for Gentle Remediation Options (GRO)

Gentle Remediation Options (GRO) are remediation measures involving plants, fungi, bacteria, and soil amendments that can be applied to manage risks at contaminated sites. Several studies and decision-support tools promote the wider range of benefits provided by GRO, but there is still skepticism regarding GRO implementation. Key issues that need to be better communicated are the various risk mitigation mechanisms, the required risk reduction for an envisioned land use, and the time perspective associated with the risk mitigation mechanisms. To increase the viability and acceptance of GRO, the phytomanagement approach implies the combination of GRO with beneficial green land use, gradually reducing risks and restoring ecosystem services. To strengthen the decision basis for GRO implementation in practice, this paper proposes a framework for risk management and communication of GRO applications to support phytomanagement strategies at contaminated sites. The mapping of the risk mitigation mechanisms is done by an extensive literature review and the Swedish national soil guideline value model is used to derive the most relevant human health exposure pathways and ecological risks for generic green land use scenarios. Results indicate that most of the expected risk mitigation mechanisms are supported by literature, but that knowledge gaps still exist. The framework is demonstrated to support the identification of GRO options for the case study site given two envisioned land uses: biofuel park and allotment garden. A more easily understandable risk management framework, as proposed here, is expected to act as a communication tool to educate decision-makers, regulatory bodies and other stakeholders for better understanding of risk mitigation mechanisms and preliminary timeframes of various GRO, particularly in the early stages of a brownfield redevelopment project

An Experimental Investigation of Colonel Blotto Games

"This article examines behavior in the two-player, constant-sum Colonel Blotto game with asymmetric resources in which players maximize the expected number of battlefields won. The experimental results support all major theoretical predictions. In the auction treatment, where winning a battlefield is deterministic, disadvantaged players use a 'guerilla warfare' strategy which stochastically allocates zero resources to a subset of battlefields. Advantaged players employ a 'stochastic complete coverage' strategy, allocating random, but positive, resource levels across the battlefields. In the lottery treatment, where winning a battlefield is probabilistic, both players divide their resources equally across all battlefields." (author's abstract)"Dieser Artikel untersucht das Verhalten von Individuen in einem 'constant-sum Colonel Blotto'-Spiel zwischen zwei Spielern, bei dem die Spieler mit unterschiedlichen Ressourcen ausgestattet sind und die erwartete Anzahl gewonnener Schlachtfelder maximieren. Die experimentellen Ergebnisse bestätigen alle wichtigen theoretischen Vorhersagen. Im Durchgang, in dem wie in einer Auktion der Sieg in einem Schlachtfeld deterministisch ist, wenden die Spieler, die sich im Nachteil befinden, eine 'Guerillataktik' an, und verteilen ihre Ressourcen stochastisch auf eine Teilmenge der Schlachtfelder. Spieler mit einem Vorteil verwenden eine Strategie der 'stochastischen vollständigen Abdeckung', indem sie zufällig eine positive Ressourcenmenge auf allen Schlachtfeldern positionieren. Im Durchgang, in dem sich der Gewinn eines Schlachtfeldes probabilistisch wie in einer Lotterie bestimmt, teilen beide Spieler ihre Ressourcen gleichmäßig auf alle Schlachtfelder auf." (Autorenreferat