Can we evaluate network brokerage initiatives using data that are byproducts of the network broking process?

Increasingly, development projects list social capital development and network brokerage among their objectives. How do we quantitatively evaluate such initiatives? Best practice, diff-in-diff methods may be impossible or too costly. Here, we try using data that are byproducts of the network broking process to evealuate the Challenge Program for Water and Food along this dimension. We find that, in accordance with its objectives, the program is associated with bridging linkages between organizations in the water and food sectors and between CGIAR members and their counterparts in government and that, in the case of the former, the association may be causal.Food production; water; Project evaluation; organizational networks; network brokerage; dyadic analysis

MEETINGS WITH COSTLY PARTICIPATION: A COMMENT

In a recent paper Osborne, Rosenthal and Turner (2000) investigate a model of meetings with costly participation. Their main result is that the equilibrium number of participants is small and their positions are extreme. In particular, when the policy space is one-dimensional and the policy outcome is the median of participants' positions, they conclude that the number of attendees is even. The proof is flawed. We construct an example with an odd number of attendees. Oddness of the number of participants has a dramatic consequence on how equilibria look like.

Schwarzschild-like black holes: Light-like trajectories and massless scalar absorption

Black holes are among the most intriguing objects in nature. They are believed to be fully described by General Relativity (GR), and the astrophysical black holes are expected to belong to the Kerr family, obeying the no-hair theorems. Alternative theories of gravity or parameterized deviations of GR allow black hole solutions, which have additional parameters other than mass and angular momentum. We analyze a Schwarzschild-like metric, proposed by Johannsen and Psaltis, characterized by its mass and a deformation parameter. We compute the absorption cross section of massless scalar waves for different values of this deformation parameter and compare it with the corresponding scalar absorption cross section of the Schwarzschild black hole. We also present analytical approximations for the absorption cross section in the high-frequency regime. We check the consistence of our results comparing the numerical and analytical approaches, finding excellent agreement.Comment: 8 pages, 14 figure