Post-plus languages

AbstractIn this paper, a post-plus language is defined as a language which contains all the catenations of each word in the language with a proper suffix of this word. The set of all d-primitive words is a natural post-plus language. The family of all post-plus languages is a subfamily of all non-counting languages. Some basic properties and characterizations of post-plus languages are investigated. We obtain that a post-plus language spanned by a word over an alphabet with two letters is context-free if and only if the language is regular. Some general properties of post-plus languages related to code, dense property and formal language theory such as the nature of context-free, context-sensitive languages are also studied in this paper

Protein Structure

Since the dawn of recorded history, and probably even before, men and women have been grasping at the mechanisms by which they themselves exist. Only relatively recently, did this grasp yield anything of substance, and only within the last several decades did the proteins play a pivotal role in this existence. In this expose on the topic of protein structure some of the current issues in this scientific field are discussed. The aim is that a non-expert can gain some appreciation for the intricacies involved, and in the current state of affairs. The expert meanwhile, we hope, can gain a deeper understanding of the topic