274 research outputs found
A Note on String Field Theory in the Temporal Gauge
In this note, we review the recent developments in the string field theory in
the temporal gauge. (Based on a talk presented by N.I. in the workshop {\it
Quantum Field Theory, Integrable Models and Beyond}, Yukawa Institute for
Theoretical Physics, Kyoto University, 14-18 February 1994.)Comment: 20 pages, KEK-TH-411, LaTex fil
Transfer Matrix Formalism for Two-Dimensional Quantum Gravity and Fractal Structures of Space-time
We develop a transfer matrix formalism for two-dimensional pure gravity. By
taking the continuum limit, we obtain a "Hamiltonian formalism'' in which the
geodesic distance plays the role of time. Applying this formalism, we obtain a
universal function which describes the fractal structures of two dimensional
quantum gravity in the continuum limit.Comment: 13 pages, 5 figures, phyzz
Activation energy for fluorine transport in amorphous silicon
The transport of ion implanted F in amorphous Si is studied using secondary ion mass spectroscopy and transmission electron microscopy. Significant redistribution of F is observed at temperatures in the range 600°C to 700°C. The measured F depth-profiles are modelled using a simple Gaussian solution to the diffusion equation, and the diffusion coefficient is deduced at each temperature. An activation energy of 2.2eV±0.4eV for F transport is extracted from an Arrhenius plot of the diffusion coefficients. It is shown that the F transport is influenced by implantation induced defects
Localized bioconvection of Euglena caused by phototaxis in the lateral direction
Euglena, a swimming micro-organism, exhibited a characteristic bioconvection
that was localized at the center of a sealed chamber under bright illumination
to induce negative phototaxis. This localized pattern consisted of high-density
spots, in which convection was found. These observations were reproduced by a
mathematical model that was based on the phototaxis of individual cells in both
the vertical and lateral directions. Our results indicate that this convection
is maintained by upward swimming, as with general bioconvection, and the
localization originates from lateral phototaxis
DAAM is required for thin filament formation and Sarcomerogenesis during muscle development in Drosophila.
During muscle development, myosin and actin containing filaments assemble into the highly organized sarcomeric structure critical for muscle function. Although sarcomerogenesis clearly involves the de novo formation of actin filaments, this process remained poorly understood. Here we show that mouse and Drosophila members of the DAAM formin family are sarcomere-associated actin assembly factors enriched at the Z-disc and M-band. Analysis of dDAAM mutants revealed a pivotal role in myofibrillogenesis of larval somatic muscles, indirect flight muscles and the heart. We found that loss of dDAAM function results in multiple defects in sarcomere development including thin and thick filament disorganization, Z-disc and M-band formation, and a near complete absence of the myofibrillar lattice. Collectively, our data suggest that dDAAM is required for the initial assembly of thin filaments, and subsequently it promotes filament elongation by assembling short actin polymers that anneal to the pointed end of the growing filaments, and by antagonizing the capping protein Tropomodulin
- …