פרסומים

ARNO is a guanine-nucleotide exchange protein for the ARF family of GTPases. Here we show that in polarized epithelial cells, ARNO is localized exclusively to the apical plasma membrane, where it regulates endocytosis. Expression of ARNO stimulates apical endocytosis of the polymeric immunoglobulin receptor, and coexpression of ARF6 with ARNO leads to a synergistic stimulation of apical endocytosis. Expression of a dominant negative ARF6 mutant, ARF6-T27N, antagonizes this stimulatory effect. Deletion of the N-terminal coiled-coil (CC) domain of ARNO causes the mutant ARNO to localize to both the apical and basolateral plasma membranes. Expression of the CC domain alone abolishes ARNO-induced apical endocytosis as well as co-localization of IgA-receptor complexes with ARNO and clathrin. These results suggest that the CC domain contributes to the specificity of apical localization of ARNO through association with components of the apical plasma membrane. We conclude that ARNO acts together with ARF6 to regulate apical endocytosis.

Since the outbreak of the Intifada in September 2000, the Israeli government has extensively employed a policy of assassinating members of Palestinian terrorist organizations. Theoretically, the net effect of an assassination on future terrorism is indeterminate because it embodies two conflicting effects: the assassination of a terrorist hurts his organization's capabilities, but may increase the motivation for future attacks. Our indirect, empirical evaluation of the effectiveness of assassinations for Isreali counterterrorism is based on Israeli stock market reactions to news of such operations. We rely on the fact that terrorism has had significant adverse effects on the Israeli economy and claim that the stock market should react positively to news about effective counterterrorism measures but negatively to news about counterproductive ones. We find that the market does not react to assassinations of low-ranked members of Palestinian terrorist organizations. The market does react strongly, however, to the assassinations of senior leaders of terrorist organizations: it declines following assassinations targeting senior political leaders but rises following assassinations of senior military leaders. To the extent that these reactions reflect expectations regarding future levels of terrorism they imply that the market perceives the first type of assassinations as counterproductive, but the second as an effective measure in combating terrorism.

While auction research, including asymmetric auctions, has grown significantly in recent years, there is still little analytical solutions of first-price auctions outside the symmetric case. Even in the uniform case, Griesmer et al. (1967) and Plum (1992) find solutions only to the case where the lower bounds of the two distributions are the same. We present the general analytical solutions to asymmetric auctions in the uniform case for two bidders, both with and without a minimum bid. We show that our solution is consistent with the previously known solutions of auctions with uniform distributions. Several interesting examples are presented including a class where the two bid functions are linear. We hope this result improves our understanding of auctions and provides a useful tool for future research in auctions.

We consider a bargaining problem where one of the players, the bureaucrat, has the power to dictate any outcome in a given set. The other players, the agents, negotiate with him which outcome to be dictated. In return, the agents transfer some part of their payoffs to the bureaucrat. We state five axioms and characterize the solutions which satisfy these axioms on a class of problems which includes as a subset all submodular bargaining problems. Every solution is characterized by a number $\pm$ in the unit interval. Each agent in every bargaining problem obtains a weighted average of his individually rational level and his marginal contribution to the set of all players, where the weights are $\pm$ and 1 - $\pm$, respectively. The bureaucrat obtains the remaing surplus. The solution when $\pm$ = 1/2 is the nucleolus of a naturally related game in characteristic form.

In daily decision making, people often solicit one another's opinions in the hope of improving their own judgment. According to both theory and empirical results, integrating even a few opinions is beneficial, with the accuracy gains diminishing as the bias of the judges or the correlation between their opinions increases. Decision makers using intuitive policies for integrating others' opinions rely on a variety of accuracy cues in weighting the opinions they receive. They tend to discount dissenters and to give greater weight to their own opinion than to other people's opinions.