General Approach to Quantum Channel Impossibility by Local Operations and Classical Communication.

We describe a general approach to proving the impossibility of implementing a quantum channel by local operations and classical communication (LOCC), even with an infinite number of rounds, and find that this can often be demonstrated by solving a set of linear equations. The method also allows one to design a LOCC protocol to implement the channel whenever such a protocol exists in any finite number of rounds. Perhaps surprisingly, the computational expense for analyzing LOCC channels is not much greater than that for LOCC measurements.

Simple and accurate sum rules for highly relativistic systems.

In this paper, I consider the Bethe and Thomas-Reiche-Kuhn sum rules, which together form the foundation of Bethe's theory of energy loss from fast charged particles to matter. For nonrelativistic target systems, the use of closure leads directly to simple expressions for these quantities. In the case of relativistic systems, on the other hand, the calculation of sum rules is fraught with difficulties.

Sickle hemoglobin fibers: mechanisms of depolymerization.

We examined the depolymerization of hemoglobin (Hb) S fibers in the presence of CO by using photolysis of COHbS to create and isolate individual fibers, then removing photolysis to induce depolymerization. Depolymerization occurs at two sites, fiber ends and fiber sides, with different kinetics and by different mechanisms. At low partial pressure of CO (pCO), end-depolymerization is dominant, proceeding at approximately 1 microm s(-1), whereas at high pCO fibers vanish very rapidly, in much less than one second, by side-depolymerization.