Seemingly Unrelated Repeated Games

Suppose Player A is playing two apparently independent repeated games with two other people, B and C, with A randomly matched, each period, with either B or C. Each dyad maintains the maximum incentive-compatible level of cooperation within the dyad, even if cooperation has broken down in the other dyad. Thus, if A defects against B, say, then C is still willing to cooperate with A to the maximum incentive-compatible degree. Nevertheless, we show that the simple presence of each cooperative relationship can increase the maximum incentive compatible level of cooperation in the other dyad, due to a counterintuitive circular reasoning or “bootstrapping” effect. With more than two relationships, bootstrapping effects alternate with equally counterintuitive reverse bootstrapping effects.Repeated Games, Random Matching

Suntracker balloon flights, flights 3026, 3028, 3029, and 3031

Suntracker balloon flight test instrumentatio

WHY BUBBLE-BURSTING IS UNPREDICTABLE: WELFARE EFFECTS OF ANTI-BUBBLE POLICY WHEN CENTRAL BANKS MAKE MISTAKES

This paper examines the effect of bubble-bursting policy in the case where the central bank sometimes tries to deflate an asset which is not, in fact, overpriced. We consider the case of a “semi-bubble,” where some traders know that an asset is overpriced, but others do not. Unlike most previous papers on bubble policy, our framework assumes rational traders. We also assume a finite time horizon, to rule out infinite horizon type bubbles. The market’s “fulfilled expectations” equilibria are derived, and standard tools of welfare economics are applied to evaluate the effect of anti-bubble policy. Under the assumption that the announcements of the financial authority can help less informed traders to learn more about a risky asset, market equilibria are presented and compared. We show that, if sellers care relatively more about the states where the central bank makes a negative bubble-bursting announcement, an announcement policy interferes with the asset’s ability to share risks. Conversely, if sellers care relatively less about the announcement states, an announcement policy improves risk sharing. “Information leakage” plays an important role in our analysis. Because of this leakage, central bank announcements can initiate further information revelation between traders. That is, the leakage effect can reveal information that the central bank, itself, does not have. However, this information leakage may not be welfare improving. Also, this leakage effect makes it difficult to predict the effects of bubble-bursting policy. This may complicate both private investment strategies and public policy analysis.greater-fool, asset bubble, asymmetric information, information leakage, Hirshleifer effect

Constraints on LVS Compactifications of IIB String Theory

We argue that once all theoretical and phenomenological constraints are imposed on the different versions of the Large Volume Scenario (LVS) compactifications of type IIB string theory, one particular version is favored. This is essentially a sequestered one in which the soft terms are generated by Weyl anomaly and RG running effects. We also show that arguments questioning sequestering in LVS models are not relevant in this case.Comment: 14 pages, additional discussion of D7 brane case and mSUGRA, reference adde

Froggatt-Nielsen models from E8 in F-theory GUTs

This paper studies F-theory SU(5) GUT models where the three generations of the standard model come from three different curves. All the matter is taken to come from curves intersecting at a point of enhanced E8 gauge symmetry. Giving a vev to some of the GUT singlets naturally implements a Froggatt-Nielsen approach to flavour structure. A scan is performed over all possible models and the results are filtered using phenomenological constraints. We find a unique model that fits observations of quark and lepton masses and mixing well. This model suffers from two drawbacks: R-parity must be imposed by hand and there is a doublet-triplet splitting problem.Comment: 42 pages; v2:journal version; v3:corrected typo in neutrino masse

Associations between selected immune-mediated diseases and tuberculosis: record-linkage studies

PMCID: PMC3616814This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited