The Arabidopsis ethylene-overproducing mutants eto1 , eto2 , and eto3 have been suggested to affect the post-transcriptional regulation of 1-aminocyclopropane-1-carboxylic acid synthase (ACS). Here, we present the positional cloning of the gene corresponding to the dominant eto3 mutation and show that the eto3 phenotype is the result of a missense mutation within the C-terminal domain of ACS9, which encodes one isoform of the Arabidopsis ACS gene family. This mutation is analogous to the dominant eto2 mutation that affects the C-terminal domain of the highly similar ACS5. Analysis of purified recombinant ACS5 and epitope-tagged ACS5 in transgenic Arabidopsis revealed that eto2 does not increase the specific activity of the enzyme either in vitro or in vivo; rather, it increases the half-life of the protein. In a similar manner, cytokinin treatment increased the stability of ACS5 by a mechanism that is at least partially independent of the eto2 mutation. The eto1 mutation was found to act by increasing the function of ACS5 by stabilizing this protein. These results suggest that an important mechanism by which ethylene biosynthesis is controlled is the regulation of the stability of ACS, mediated at least in part through the C-terminal domain.

Interactive environments for dynamically deforming objects play an important role in surgery simulation and entertainment technology. These environments require fast deformable models and very efficient collision handling techniques. While collision detection for rigid bodies is well-investigated, collision detection for deformable objects introduces additional challenging problems. This paper focuses on these aspects and summarizes recent research in the area of deformable collision detection. Various approaches based on bounding volume hierarchies

SOFA (Simulation Open Framework Architecture) is an open-source C++ library primarily targeted at interactive computational medical simulation. SOFA facilitates collaborations between specialists from various domains, by decomposing complex simulators into components designed independently and organized in a scenegraph data structure. Each component encapsulates one of the aspects of a simulation, such as the degrees of freedom, the forces and constraints, the differential equations, the main loop algorithms, the linear solvers, the collision detection al- Authors Suppressed Due to Excessive Length gorithms or the interaction devices. The simulated objects can be represented using several models, each of them optimized for a different task such as the computation of internal forces, collision detection, haptics or visual display. These models are synchronized during the simulation using a mapping mechanism. CPU and GPU implementations can be transparently combined to exploit the computational power of modern hardware architectures. Thanks to this flexible yet efficient architecture, SOFA can be used as a test-bed to compare models and algorithms, or as a basis for the development of complex, high-performance simulators.