Economic Exit, Interdependence, and Conflict

This article examines the question of whether economic interdependence constrains or motivates interstate conflict. The theoretical model predicts when and how interdependence influences conflict, using exit costs to separate economic interdependence from less binding economic interaction. Analysis of the model suggests that when exit costs exceed an endurance threshold for at least one state, the threat of exit becomes a viable but limited bargaining tool. Exceeding this threshold increases low-level conflict as states use economic and diplomatic tools to resolve demands, but it decreases high-level conflict because states take advantage of more efficient means of dispute resolution. If the stakes are too high, however, exit costs fail to check conflict, and the economic relationship becomes an ineffective bargaining arena. Empirical analysis provides support for the hypotheses derived from the model

Galaxy Zoo: quantitative visual morphological classifications for 48 000 galaxies from CANDELS

We present quantified visual morphologies of approximately 48 000 galaxies observed in three Hubble Space Telescope legacy fields by the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS) and classified by participants in the Galaxy Zoo project. 90 per cent of galaxies have z ≤ 3 and are observed in rest-frame optical wavelengths by CANDELS. Each galaxy received an average of 40 independent classifications, which we combine into detailed morphological information on galaxy features such as clumpiness, bar instabilities, spiral structure, and merger and tidal signatures. We apply a consensus-based classifier weighting method that preserves classifier independence while effectively down-weighting significantly outlying classifications. After analysing the effect of varying image depth on reported classifications, we also provide depth-corrected classifications which both preserve the information in the deepest observations and also enable the use of classifications at comparable depths across the full survey. Comparing the Galaxy Zoo classifications to previous classifications of the same galaxies shows very good agreement; for some applications, the high number of independent classifications provided by Galaxy Zoo provides an advantage in selecting galaxies with a particular morphological profile, while in others the combination of Galaxy Zoo with other classifications is a more promising approach than using any one method alone. We combine the Galaxy Zoo classifications of ‘smooth’ galaxies with parametric morphologies to select a sample of featureless discs at 1 ≤ z ≤ 3, which may represent a dynamically warmer progenitor population to the settled disc galaxies seen at later epochs

Built to Last: Understanding the Link between Democracy and Conflict in the International System

We revisit Gartzke and Weisiger's (2014) claim that development and dyadic difference, rather than democracy or a strong democratic community, drive peace and conflict in the international system. In so doing, we identify important inconsistencies in their theoretical argument. We also find extensive instability and errors in their empirical tests. Corrected analyses support the conclusion that a materially strong global democratic community dampens the onset of militarized violence. In addition, we show that an accurate interpretation of models including Gartzke and Weisiger's “dyadic difference” variable actually supports the conclusion that dyadic democracy reduces conflict. We recommend moving toward a more productive analysis of the interdependence between regime dynamics, political economy, and violence. This involves better theorizing about the emergence of market structures and their pacifying effects, treating global economic and democratic effects as complementary, research designs that carefully adhere to logic, and a continued practice of sharing replication files