Interactive Unawareness Revisited

We analyze a model of interactive unawareness introduced by Heifetz, Meier and Schipper (HMS). We consider two axiomatizations for their model, which capture different notions of validity. These axiomatizations allow us to compare the HMS approach to both the standard (S5) epistemic logic and two other approaches to unawareness: that of Fagin and Halpern and that of Modica and Rustichini. We show that the differences between the HMS approach and the others are mainly due to the notion of validity used and the fact that the HMS is based on a 3-valued propositional logic.Comment: 26 page

Extensive Games with Possibly Unaware Players

Standard game theory assumes that the structure of the game is common knowledge among players. We relax this assumption by considering extensive games where agents may be unaware of the complete structure of the game. In particular, they may not be aware of moves that they and other agents can make. We show how such games can be represented; the key idea is to describe the game from the point of view of every agent at every node of the game tree. We provide a generalization of Nash equilibrium and show that every game with awareness has a generalized Nash equilibrium. Finally, we extend these results to games with awareness of unawareness, where a player i may be aware that a player j can make moves that i is not aware of, and to subjective games, where payers may have no common knowledge regarding the actual game and their beliefs are incompatible with a common prior.Comment: 45 pages, 3 figures, a preliminary version was presented at AAMAS0

Why are Chloris gayana leaves shorter in salt-affected plants? Analyses in the elongation zone

Reduced hydraulic conductance calculated from growth data was suggested to be the main reason for reduced leaf expansion in salt-stressed Chloris gayana (Rhodes grass). In this work, xylem vessel cross-sections and wall enzyme activities were analysed to re-examine the effects of salinity on leaf growth in this species. Maximal segmental growth rates were 20% lower and the growth zone was 23% shorter in leaves from salinized plants than in controls; however, growth rates between 0 mm and 15 mm from the ligule were similar in both types of leaves. Xylem cross-sectional areas in this region were about 65% smaller in leaves of salinized plants, suggesting that hydraulic restrictions in the leaves of salinized plants were much higher than overall growth reductions. Extractable xyloglucan endotransglucosylase activity in this zone was twice as high in leaves of salinized plants as in leaves of controls. Nevertheless, the activity of the extracted enzyme was not affected by up to 1 M NaCl added to the reaction medium. Therefore, increased xyloglucan endotransglucosylase activity under salinity may be due to a promotion of transcription of XTH (xyloglucan endotransglucosylase/hydrolases) genes and/or translation of preformed transcripts. These results suggest that, as in drought stress, increased activity of cell wall enzymes associated with wall loosening may contribute to the maintenance of growth under saline conditions despite hydraulic restrictions.Instituto de Fisiología y Recursos Genéticos VegetalesFil: Ortega, Leandro Ismael. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Fisiología y Recursos Genéticos Vegetales (ex IFFIVE); ArgentinaFil: Fry, Stephen C. University of Edinburgh. Institute of Molecular Plant Sciences. The Edinburgh Cell Wall Group; Gran BretañaFil: Taleisnik, Edith. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Fisiología y Recursos Genéticos Vegetales (ex IFFIVE); Argentina

Regional differences in intelligence and per capita income in Portugal

Regional differences in IQ and per capita incomes are presented for five regions of Portugal: North, North Central, Lisbon-Central, Lisbon-Suburb, and South. Regional IQs were calculated from a representative sample of 4548 Portuguese school students from 5th to 12th grades. The average IQ and average incomes are highest in Central Lisbon. The results show a positive association between IQs and average regional incomes, as it has been observed in other countries