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.

Sales Taxes and Prices: An Empirical Analysis

One of the most fundamental questions in public finance is who bears the burden of taxes -- the incidence of taxation.' Our understanding of incidence from an empirical standpoint is quite meager. Indeed, there seems to be little evidence even in the case that is theoretically the easiest -- partial equilibrium commodity taxes. Are taxes levied on commodities completely shifted into their prices, or does the incidence also fall on firms? How long does the shifting process take? In this paper we employ a unique data source to examine the incidence of sales taxes. The main idea is to take information on the prices of specific commodities in different U.S. cities and to examine the extent to which differences in tax rates and bases are reflected in prices, controlling for other factors (such as costs). We find a surprising variety of shifting patterns. For some commodities, the after-tax price increases by exactly the amount of the tax, a result consistent with the standard competitive model. However, taxes on other commodities are overshifted -- an increase in tax revenue of one dollar per unit increases the price by more than one dollar.

Computational evaluation of the impact of incorporated nitrogen and oxygen heteroatoms on the affinity of polyaromatic ligands for carbon dioxide and methane in metal–organic frameworks

Density functional theory is employed to explore the binding of carbon dioxide and methane in a series of isoreticular metal–organic frameworks, with particular emphasis on understanding the impact of directly incorporated nitrogen and oxygen heteroatoms on the affinity of the ligand for CO2 and CH4. While the strongest binding sites for both CO2 and CH4 were found to be directly above the aromatic rings of the core of the ligand, the introduction of heteroatoms to the core systems was shown to significantly alter both the binding strength and preferred binding locations of CH4 and CO2. The presence of pyrazine rings within the ligand was observed to create new binding sites for both CO2 and CH4 and, in the case of CO2, severely reduce the binding strength or entirely eliminate binding sites that were prominent in the analogous carbocyclic ligands. These results suggest that while the presence of framework nitrogen and oxygen heteroatoms provides a route to ligands with enhanced affinity for methane, a similar increase in affinity for CO2 is not guaranteed

Computational evaluation of the impact of incorporated nitrogen and oxygen heteroatoms on the affinity of polyaromatic ligands for carbon dioxide and methane in metal–organic frameworks

Density functional theory is employed to explore the binding of carbon dioxide and methane in a series of isoreticular metal–organic frameworks, with particular emphasis on understanding the impact of directly incorporated nitrogen and oxygen heteroatoms on the affinity of the ligand for CO2 and CH4. While the strongest binding sites for both CO2 and CH4 were found to be directly above the aromatic rings of the core of the ligand, the introduction of heteroatoms to the core systems was shown to significantly alter both the binding strength and preferred binding locations of CH4 and CO2. The presence of pyrazine rings within the ligand was observed to create new binding sites for both CO2 and CH4 and, in the case of CO2, severely reduce the binding strength or entirely eliminate binding sites that were prominent in the analogous carbocyclic ligands. These results suggest that while the presence of framework nitrogen and oxygen heteroatoms provides a route to ligands with enhanced affinity for methane, a similar increase in affinity for CO2 is not guaranteed

Interaction of the NO 3pπ (C 2Π) Rydberg state with RG (RG = Ne, Kr, and Xe): potential energy surfaces and spectroscopy

We present new potential energy surfaces for the interaction of NO(C 2Π) with each of Ne, Kr, and Xe. The potential energy surfaces have been calculated using second order Møller-Plesset perturbation theory, exploiting a procedure to converge the reference Hartree-Fock wavefunction for the excited states: the maximum overlap method. The bound rovibrational states obtained from the surfaces are used to simulate the electronic spectra and their appearance is in good agreement with available (2+1) REMPI spectra. We discuss the assignment and appearance of these spectra, comparing to that of NO-Ar

Protein fiber linear dichroism for structure determination and kinetics in a low-volume, low-wavelength couette flow cell

High-resolution structure determination of soluble globular proteins relies heavily on x-ray crystallography techniques. Such an approach is often ineffective for investigations into the structure of fibrous proteins as these proteins generally do not crystallize. Thus investigations into fibrous protein structure have relied on less direct methods such as x-ray fiber diffraction and circular dichroism. Ultraviolet linear dichroism has the potential to provide additional information on the structure of such biomolecular systems. However, existing systems are not optimized for the requirements of fibrous proteins. We have designed and built a low-volume (200 μL), low-wavelength (down to 180 nm), low-pathlength (100 μm), high-alignment flow-alignment system (couette) to perform ultraviolet linear dichroism studies on the fibers formed by a range of biomolecules. The apparatus has been tested using a number of proteins for which longer wavelength linear dichroism spectra had already been measured. The new couette cell has also been used to obtain data on two medically important protein fibers, the all-β-sheet amyloid fibers of the Alzheimer's derived protein Aβ and the long-chain assemblies of α1-antitrypsin polymers

Amides do not always work: observation of guest binding in an amide-functionalised porous host

An amide-functionalised metal organic frame-work (MOF) material, MFM-136, shows a high CO2 uptake of 12.6 mmol g-1 at 20 bar and 298 K. MFM-136 is the first example of acylamide pyrimidyl isophthalate MOF without open metal sites, and thus provides a unique platform to study guest bind-ing, particularly the role of free amides. Neutron diffraction reveals that, surprisingly, there is no direct binding between the adsorbed CO2/CH4 molecules and the pendant amide group in the pore. This observation has been confirmed un-ambiguously by inelastic neutron spectroscopy. This suggests that introduction of functional groups solely may not neces-sarily induce specific guest-host binding in porous materials, but it is a combination of pore size, geometry, and functional group that leads to enhanced gas adsorption properties

Tailoring porosity and rotational dynamics in a series of octacarboxylate metal-organic frameworks

Modulation and precise control of porosity of metal-organic frameworks (MOFs) are of critical importance to their materials function. Here we report the first modulation of porosity for a series of isoreticular octacarboxylate MOFs, denoted MFM-180 to MFM-185, via a strategy of selective elongation of metal-organic cages. Owing to the high ligand connectivity, these MOFs show absence of network interpenetration, robust structures and permanent porosity. Interestingly, activated MFM-185a shows a record high BET surface area of 4734 m2 g-1 for an octacarboxylate MOF. These MOFs show remarkable CH4 and CO2 adsorption properties, notably with simultaneously high gravimetric and volumetric deliverable CH4 capacities of 0.24 g g-1 and 163 v/v (298 K, 5-65 bar) recorded for MFM-185a due to selective elongation of tubular cages. Dynamics of molecular rotors in deuterated MFM-180a-d16 and MFM-181a-d16 were investigated by variable-temperature 2H solid state NMR spectroscopy to reveal the reorientation mechanisms within these materials. Analysis of the flipping modes of the mobile phenyl groups on the linkers, their rotational rates and transition temperatures, paves the way to controlling and understanding the role of molecular rotors through organic linker design within porous MOF materials