Whenever one deals with an interactive decision situation of long duration, one has to take into account that priorities of the participants 5 change during the conflict. In this paper we propose an extensive-form game model to handle such situations and suggest and study a solution concept, called credible equilibrium, which generalizes the concept of Nash equilibrium. We also discuss possible variants to this concept and applications of the model to other types of games.
The yield for photodissociation of Cl2 in solid Ar was measured experimentally as a function of photon energy and studied by molecular dynamics simulations. The results show that separation of the Cl fragments at low energies occurs by delayed exit (t greater than or similar to 3 ps) from the surrounding cage of Ar atoms. Above a photon threshold energy of greater than or similar to 9.0 eV, there is a switchover to direct cage exit, in which the Cl impulsively knocks a cage atom out of its way. The results are a first demonstration of delayed cage exit and of changeover from delayed to direct exit in solid-state photolysis.
An easy approach for constructing gold electrodes embedded in glass is described. A special "soft" glass, with a thermal expansion coeff. matching that of gold has enabled assembling gold electrodes which exhibit good sealing and thus excellent electrochem. response. [on SciFinder(R)]
The photolysis of HCl in the cluster Ar ... HCl is studied theoretically with the objective of elaborating on the effect of a single ``solvent'' atom on the dynamics of chemical bond breaking. The focus is on observable properties, such as the velocity distribution and the angular distribution of the H atom product, on how these properties reflect the ``solvent'' effect, and on the physical mechanisms involved. The main results obtained are the following. (1) There is a high probability for at least a single ``hard'' collision,between the H photofragment and the Ar atom before the H atom leaves the cluster. Multiple collisions between the H and the heavy atoms also occur with significant probability. (2) The final kinetic-energy distribution of the H atom shows a long pronounced tail due to energy transfer in the collisions with the heavy atoms. (3) There are pronounced peaks in the angular distribution of the H atom due to the single and multiple collision events. (4) Comparison of photolysis of Ar ... HCl with that of Ar ... DCl shows a large isotope effect, again due to collisions within the cluster during its fragmentation. The results were mostly obtained from classical trajectory calculations, but also in part from calculations using a hybrid quantum/classical method in which the H atom is treated by quantum wave packets while the heavy atoms are described classically. The quantitative results show some quantum effects, but for most purposes the classical description is sustained. Implications of the results for experimental studies of molecular photodissociation in clusters are discussed.
This is the second of two papers developing the theory of Egalitarian solutions for games in coalitional form with non-transferable utility (NTU) and a large number of players. This paper is devoted to the study of the egalitarian solutions of finite games as the number of players increases. We show that these converge to the egalitarian solution of the limit game with a continuum of players as defined in our previous paper. The same convergence holds for the underlying potential functions.
Although much is known about the hormonal regulation of osteoblastic cell differentiation, much less is known about the nuclear regulatory molecules that affect this process. We analyzed the expression of several regulatory molecules of the helix-loop-helix (H-L-H) group in primary mouse calvarial cells and in MC3T3-E1 mouse osteoblastic cells in situations representing different degrees of cellular differentiation. H-L-H class regulators are known to participate directly in directing cell fate and differentiation decisions in other mesodermal lineages. Two of the molecules that we studied, Id and E12, have well-established roles in this process. The other, mTwi, the murine homolog of the Drosophila twist gene, is a newly cloned mammalian H-L-H gene. Levels of E12 RNA remained unchanged during differentiation. On the other hand, in both primary osteoblastic cells and MC3T3-E1 cells, the abundance of Id and mTwi declined with cell maturation; mTwi less dramatically than Id. That Id expression is causally related to differentiation is suggested by the finding that MC3T3-E1 cells transfected with an Id-expression plasmid fail to undergo differentiation. We conclude that helix-loop-helix regulatory genes are expressed in mouse osteoblastic cells, where they are likely to participate in differentiation. The E12 gene product is likely to function as a positive modulating factor. In contrast, Id inhibits differentiation, probably by sequestering other H-L-H gene regulators, including E12, in inactive complexes. The precise role of mTwi is more speculative at this time, but the observed pattern of expression is consistent with a role in early and midmesodermal specification that is terminated as cells differentiate.
We consider the effect of shear velocity gradients on the size (L) of rodlike micelles in dilute and semidilute solution. A kinetic equation is introduced for the time-dependent concentration of aggregates of length L, consisting of ``bimolecular'' combination processes L + L' –> (L + L') and ``unimolecular'' fragmentations L –> L' + (L - L'). The former are described by a generalization (from spheres to rods) of the Smoluchowski mechanism for shear-induced coalescence of emulsions, and the latter by incorporating the tension-deformation effects due to flow. Steady-state solutions to the kinetic equation are obtained, with the corresponding mean micellar size (LBAR) evaluated as a function of the Peclet number P, i.e., the dimensionless ratio of flow rate-gamma and rotational diffusion coefficient D(r). For sufficiently dilute solutions, we find only a weak dependence of LBAR on P. In the semidilute regime, however, an apparent divergence in LBAR at P congruent-to 1 suggests a flow-induced first-order gelation phenomenon.
