Journal Staff

Our society is faced with a number of major challenges. Critical matters like financial tension, pollution, and safety and health issues prove to be difficult to solve with just one simple answer. In many cases these major challenges cannot be unravelled by traditional means and solutions, but require a radical approach to move towards a more sustainable and balanced society. To reach a new equilibrium we need to confront today’s challenges by exploring new ways of thinking and working. By doing so, it is necessary to develop new frameworks, methods, and tools in order to come up with new systematic designs, which create opportunities to transform our society.

Monopolistic Competition and International Trade: Reconsidering the Evidence

In this paper, we test some propositions about international trade flows that are derived from a model of monopolistic competition developed by Elhanan Helpman. We investigate whether the volume of trade between OECD countries is consistent with the predictions of a modal in which all trade is intra-industry trade in differentiated products. We then repeat the test with non-OECD countries. We also investigate whether the share of intra-industry trade is consistent with a more general theoretical model in which some, but not all, trade is intra-industry trade. Our results lead us to question the apparent empirical success of these models.

Explaining Home Bias in Consumption: The Role of Intermediate Input Trade

We show that 'home bias' in trade patterns will arise endogenously due to the co-location decisions of intermediate and final goods producers. Our model identifies four implications of home bias arising out of specialized industrial demands. Regions absorb different bundles of goods. Buyers and sellers of intermediate goods co-locate. Intermediate input trade is highly localized. The effect of spatial frictions on trade are magnified. These implications are examined and confirmed using a unique data source that matches the detailed subnational geography of shipments to the characteristics of the shipping establishments. Our results broaden the measurement and interpretation of home bias, and provide new evidence on the role of intermediate inputs in concentrating production.

Intra-national Home Bias: Some Explanations

Wolf (2000) demonstrates that trade within the U.S. appears substantially impeded by state borders. We revisit this finding with improved data. We show that much intra-national home bias can be explained by wholesaling activity. Shipments by wholesalers are much more localized within states than shipments from manufacturing establishments. Controlling for relative prices and the use of actual, rather than imputed, shipment distances also reduces home bias estimates.

Trident: a universal tool for generating synthetic absorption spectra from astrophysical simulations

Hydrodynamical simulations are increasingly able to accurately model physical systems on stellar, galactic, and cosmological scales, however, the utility of these simulations is often limited by our ability to directly compare them with the datasets produced by observers: spectra, photometry, etc. To address this problem, we have created Trident}, a Python-based, open-source tool for post-processing hydrodynamical simulations to produce synthetic absorption spectra and related data. Trident} can (i) create absorption-line spectra for any trajectory through a simulated dataset mimicking both background quasar and down-the-barrel configurations, (ii) reproduce the spectral characteristics of common instruments like the Cosmic Origins Spectrograph, (iii) operate across the ultraviolet, optical and infrared using customizable absorption line lists, (iv) trace simulated physical structures directly to spectral features, (v) approximate the presence of ion species absent from the simulation outputs, (vi) generate column density maps for any ion, and (vii) provide support for all major astrophysical hydrodynamical codes. The focus of Trident's development is for using simulated datasets to better interpret observations of the circumgalactic medium (CGM) and intergalactic medium (IGM), but it remains a general tool applicable in other contexts.Comment: 16 pages, 13 figures, published in ApJ, Code available at http://trident-project.or

The Trade Reducing Effects of Market Power in International Shipping

Developing countries pay substantially higher transportation costs than developed nations, which leads to less trade and perhaps lower incomes. This paper investigates price discrimination in the shipping industry and the role it plays in determining transportation costs. In the presence of market power, shipping prices depend on the demand characteristics of goods being traded. We show theoretically and estimate empirically that shipping firms charge higher prices when transporting goods with higher product prices, lower import demand elasticities, and higher tariffs, and when facing fewer competitors on a trade route. These characteristics explain more variation in shipping prices than do conventional proxies such as distance, and significantly contribute to the higher shipping prices facing the developing world. Markups increase shipping prices by at least 83 percent for the mean shipment in Latin American imports. Our findings are also important for evaluating the impact of tariff liberalization. Shipping firms decrease prices by 1-2 percent for every 1 percent reduction in tariffs.