An ionic current model of the retinal horizontal cell is constructed. The horizontal cell models are interconnected by gap junctions to form a horizontal cell layer. The light response properties of the L-type horizontal cell are analyzed using this model. We demonstrate the functional role of each ionic current and the role of the feedback loop between cones and horizontal cells. The present s...

We describe a stochastic birth-and-death model of evolution of horizontally transferred genes in microbial populations. The model is a generalization of the stochastic model described by Berg and Kurland and includes five parameters: the rate of mutational inactivation, selection coefficient, invasion rate (i.e., rate of arrival of a novel sequence from outside of the recipient population), wit...

abstract : horizontal root fractures in permanent teeth are uncommon injuries among dental traumas. the principle of treating horizontal root fractures of permanent teeth is repositioning and fixation of fractured segment. diagnosis of tooth fractures based on radiographic findings and the fracture healing process are affected by factors before and after injury. the present case reports the tre...

We investigate the selective forces that promote the emergence of modularity in nature. We demonstrate the spontaneous emergence of modularity in a population of individuals that evolve in a changing environment. We show that the level of modularity correlates with the rapidity and severity of environmental change. The modularity arises as a synergistic response to the noise in the environment ...

recognition of relationship between the present day stress state and fractures is very important in fractured reservoirs. fractures that are parallel or oblique to maximum horizontal stress have more tendencies to tensile deformation and tensile deformed fractures will be more permeable. the dalan formation is one of the main gas reservoirs of iran witch most of the production from this formati...

This is a contribution to the history of scientific advance in the past 70 years concerning the identification of genetic information, its molecular structure, the identification of its functions and the molecular mechanisms of its evolution. Particular attention is thereby given to horizontal gene transfer among microorganisms, as well as to biosafety considerations with regard to beneficial a...

This article reviews research on the evolutionary mechanisms leading to different transmission modes. Such modes are often under genetic control of the host or the pathogen, and often in conflict with each other via trade-offs. Transmission modes may vary among pathogen strains and among host populations. Evolutionary changes in transmission mode have been inferred through experimental and phyl...