The paper shows how the diffusive movement of ions through a channel protein can be described as a chemical reaction over an arbitrary shaped potential barrier. The result is simple and intuitive but without approximation beyond the electrodiffusion description of ion movement.

We introduce a model detector which registers the passage of a particle through the detector location, without substantially perturbing the particle wave function. (The exact time of passage is not determined in such measurements.) We then show that our detector can operate in a classically forbidden region and register particles passing through a certain point under a potential barrier. We sho...

BACKGROUND AND AIMS Growth in trunk height in canopy openings is important for saplings. How saplings increase height growth in canopy openings may relate to crown architectural constraints. Responses of crown development to canopy openings in relation to trunk height growth were studied for saplings (0.2-2.5 m tall) of eight tropical submontane forest tree species in Indonesia. The results of ...

The openings of transverse tubules in frog twitch fibers are described. The tubules open to the extracellular space by a narrow neck, with an inner diameter of 20 nm. The most peripheral portion of the tubules is tortuous and has a variable diameter. The similarity in size of the openings of T tubules and caveolae and the meandering path of the tubules are sufficient to account for the paucity ...

Losing Chess is a chess variant where each player tries to lose all one’s pieces. As the naming of “Giveaway” variants has multiple schools of terminology, we state for definiteness that captures are compulsory (a player with multiple captures chooses which to make), a King can be captured like any other piece, Pawns can promote to Kings, and castling is not legal. There are competing rulesets ...

Path openings and closings are algebraic morphological operators using families of thin and oriented structuring elements that are not necessarily perfectly straight. These operators are naturally translation invariant and can be used in filtering applications instead of operators based on the more standard families of straight line structuring elements. They give similar results to area or att...

Network connectivity is usually addressed for convex domains where a direct line of sight exists between any two transmitting/receiving nodes. Here, we develop a general theory for the network connectivity properties across a small opening, rendering the domain essentially non-convex. Our analytic approach can go only so far as we encounter what is referred to in statistical physics as quenched...