The effect of Surface Heterogeneity on the Temperature-Humidity Correlation and the Relative Transport Efficiency

We derive a conceptual model of the flow over heterogeneous terrain consisting of patches with contrasting Bowen ratios. Upward moving eddies are assumed to carry heterogeneous properties, whereas downward moving eddies carry homogeneous properties. This results in a decorrelation of temperature and humidity as the contrast between the patches increases. We show that this model is able to reproduce the relationship developed by Lamaud and Irvine (Boundary-Layer Meteorol. 120:87¿109, 2006). Some details differ from their expression but are in accordance with data obtained over African savannah. We extend the conceptual model to a combination of any scalars, not necessarily linked through the surface energy balance (as is the case for temperature and humidity). To this end we introduce a new parameter that describes the surface heterogeneity in surface fluxes. The results of the current model can be used to predict the discrepancy between similarity relationships for different scalars over heterogeneous terrai

Battlefields and Marketplaces

Divided societies in the developing world experience wasteful struggles for power. We study the relationship between political stability and resources wasted in the struggle within a model of competitive power contests. The model of power contests is similar in structure to models describing oligopolistic market competition. This analogy helps us in deriving results that are new to the conflict literature. We show, for example, that the Herfindahl-Hirschman index can be interpreted as a measure of power concentration and that a peace treaty between fighting groups have a parallel in tacit collusion between firms in a market.Violent conflicts, Rent-seeking games, Herfindahl-Hirschman index, Oligopolistic competition.

King of the Hill Positional Dynamics in Contests

In a contest with positional dynamics between an incumbent and a challenger i) inequality of power may magnify conflicts, ii) more severe conflicts can go together with lower turnover of incumbents, and iii) power can be self defeating as cost advantages can reduce pay-offs. These three propositions of our paper are contrary to the implications of static conflict models. They follow from incorporating positional dynamics into the standard static approach. Such positional dynamics are relevant for competition in battlefields, politics, and market places.Contests;political stability;war;incumbency advantage

Institutions and the resource curse

Countries rich in natural resources constitute both growth losers and growth winners. We claim that the main reason for these diverging experiences is differences in the quality of institutions. More natural resources push aggregate income down, when institutions are grabber friendly, while more resources raise income, when institutions are producer friendly. We test this theory building on Sachs and Warner's influential works on the resource curse. Our main hypothesis: that institutions are decisive for the resource curse, is confirmed. Our results are in sharp contrast to the claim by Sachs and Warner that institutions do not play a role.Natural resources, Institutional quality, Growth, Rent-seeking

Institutions and the Resource Curse

Countries rich in natural resources constitute both growth losers and growth winners. We claim that the main reason for these diverging experiences is differences in the quality of institutions. More natural resources push aggregate income down, when institutions are grabber friendly, while more resources raise income, when institutions are producer friendly. We test this theory building on Sachs and Warner's influential works on the resource curse. Our main hypothesis: that institutions are decisive for the resource curse, is confirmed. Our results are in sharp contrast to the claim by Sachs and Warner that institutions do not play a role.Natural resources, Institutional quality, Growth, Rent-seeking

Institutions and the resource curse

Countries rich in natural resources constitute both growth losers and growth winners. We claim that the main reason for these diverging experiences is differences in the quality of institutions. More natural resources push aggregate income down, when institutions are grabber friendly, while more resources raise income, when institutions are producer friendly. We test this theory building on Sachs and Warner's influential works on the resource curse. Our main hypothesis: that institutions are decisive for the resource curse, is confirmed. Our results are in sharp contrast to the claim by Sachs and Warner that institutions do not play a role.Natural resources, Institutional quality, Growth, Rent-seeking

Destructive Creativity

Destructive creativity implies that parasites become more efficient in rent extraction. We focus on destructive creativity in situations where parasites live on rents extracted from the producers. A higher parasitic strength implies that the waste associated with rent seeking increases, and in the long run erodes business productivity, implying that the sustainability of predation is threatened by improved efficiency.

Cursed by resources or institutions?

Natural resource abundant countries constitute both growth losers and growth winners, and the main difference between the success cases and the cases of failure lays in the quality of institutions. With grabber friendly institutions more natural resources push aggregate income down, while with producer friendly institutions more natural resources increase income. Such a theory finds strong support in data. A key question we also discuss is if resources in addition alter the quality of institutions. When that is the case, countries with bad institutions suffer a double resource curse - as the deterioration of institutions strenghtens the negative effect of more natural resources.Natural resources; Institutional quality; Growth; Rent-seeking