The Incidence of Civil War: Theory and Evidence

This paper studies the incidence of civil war over time. We put forward a canonical model of civil war, which relates the incidence of conflict to circumstances, institutions and features of the underlying economy and polity. We use this model to derive testable predictions and to interpret the cross-sectional and times-series variations in civil conflict. Our most novel emprical finding is that higher world market prices of exported, as well as imported, commodities are strong and significant predictors of higher within-country incidence of civil war.

State Capacity, Conflict and Development

We report on an on-going project, which asks a number of questions relevant to the study of state capacity. What are the main economic and political determinants of the state’s capacity to raise revenue and support private markets? How do risks of violent conflict affect the incentives to invest in state building? Does it matter whether conflicts are external or internal to the state? When are large states associated with higher income levels and growth rates than small states? What relations should we expect between resource rents, civil wars and economic development? The paper is organized into three main sections: 1. The origins of state capacity, 2. Sate capacity and the genius of taxation, and 3. State capacity and the strategy of conflict. Each of these begins with a specific motivation. A simple model is formulated to analyze the determinants of state capacity in the first section, and modified to address the new issues that arise in subsequent sections. The theoretical results are summarized in a number of propositions. We discuss the implications of the theory, comment on its relation to existing literature, and briefly mention some empiric applications.

The Aggregate Consequences of Default Risk: Evidence from Firm-level Data

This paper studies the implications of perceived default risk for aggregate output and productivity. Using a model of credit contracts with moral hazard, we show that a firm’s probability of default is a sufficient statistic for capital allocation. The t

Computational study of the structure and electronic circular dichroism spectroscopy of blue copper proteins

The calculation of the electronic circular dichroism (CD) spectra of the oxidised form of the blue copper proteins plastocyanin and cucumber basic protein and the relationship between the observed spectral features and the structure of the active site of the protein is investigated. Excitation energies and transition strengths are computed using multi reference configuration interaction, and it is shown that computed spectra based on coordinates from the crystal structure or a single structure optimised in quantum mechanics/molecular mechanics (QM/MM) or ligand field molecular mechanics (LFMM) are qualitatively incorrect. In particular, the rotational strength of the ligand to metal charge transfer band is predicted to be too small or have the incorrect sign. By considering calculations on active site models with modified structures it is shown that the intensity of this band is sensitive to the non-planarity of the histidine and cysteine ligands coordinated to copper. Calculation of the ultraviolet absorption and CD spectra based upon averaging over many structures drawn from a LFMM molecular dynamics simulation are in good agreement with experiment, and superior to analogous calculations based upon structures from a classical molecular dynamics simulation. This provides evidence that the LFMM force field provides an accurate description of the molecular dynamics of these proteins

Simulation of the Raman spectroscopy of multi-layered carbon nanomaterials

Multi-layered carbon nanomaterials can have an important role in modern nanotechnology. Raman spectroscopy is a widely used analytical technique that is used to characterise the structure of these materials. In this work, an approach based upon an empirical potential for the simulation of the Raman spectroscopy of carbon nanomaterials [Carbon, 113 (2017) 299] is extended through the addition of a term to describe the Van der Waals interaction between layers of sp2 hybridised carbons. The resulting model accurately describes the properties of the shearing modes of few layer graphene and is used to characterise the low frequency modes of multi-walled carbon nanotubes and carbon nanofibres

Warfare, Fiscal Capacity, and Performance

We exploit differences in casualties sustained in pre-modern wars to estimate the impact of fiscal capacity on economic performance. In the past, states fought different amounts of external conflicts, of various lengths and magnitudes. To raise the revenues to wage wars, states made fiscal innovations, which persisted and helped to shape current fiscal institutions. Economic historians claim that greater fiscal capacity was the key long-run institutional change brought about by historical conflicts. Using casualties sustained in pre-modern wars to instrument for current fiscal institutions, we estimate substantial impacts of fiscal capacity on GDP per worker. The results are robust to a broad range of specifications, controls, and sub-samples

Electrostatic interactions between spheroidal dielectric particles

Theory is developed to address the significant problem of electrostatic interactions between charged polarizable dielectric spheroids. The electrostatic force is defined by particle dimensions and charge, dielectric constants of the interacting particles and medium, and the interparticle separation distance; and it is expressed in the form of an integral over the particle surface. The switching behavior between like charge repulsion and attraction is demonstrated as depending on the ratio of the major and minor axes of spheroids. When the major and minor axes are equal, the theory yields a solution equivalent to that obtained for spherical particles. Limiting cases are presented for nonpolarizable spheroids, which describe the electrostatic behavior of charged rods, discs, and point charges. The developed theory represents an important step toward comprehensive understanding of direct interactions and mechanisms of electrostatically driven self-assembly processes

Dynamic simulations of many-body electrostatic self-assembly

Two experimental studies relating to electrostatic self-assembly have been the subject of dynamic computer simulations, where the consequences of changing the charge and the dielectric constant of the materials concerned have been explored. One series of calculations relates to experiments on the assembly of polymer particles that have been subjected to tribocharging and the simulations successfully reproduce many of the observed patterns of behaviour. A second study explores events observed following collisions between single particles and small clusters composed of charged particles derived from a metal oxide composite. As before, observations recorded during the course of the experiments are reproduced by the calculations. One study in particular reveals how particle polarisability can influence the assembly process

Fast time-dependent density functional theory calculations of the x-ray absorption spectroscopy of large systems

The computational cost of calculations of K-edge X-ray absorption spectra using time-dependent density functional (TDDFT) within the Tamm−Dancoff approximation is significantly reduced through the introduction of a severe integral screening procedure that includes only integrals that involve the core s basis function of the absorbing atom(s) coupled with a reduced quality numerical quadrature for integrals associated with the exchange and correlation functionals. The memory required for the calculations is reduced through construction of the TDDFT matrix within the absorbing core orbitals excitation space and exploiting further truncation of the virtual orbital space. The resulting method, denoted fTDDFTs, leads to much faster calculations and makes the study of large systems tractable. The capability of the method is demonstrated through calculations of the X-ray absorption spectra at the carbon K-edge of chlorophyll a, C60 and C70