On the relationship between the angular deficit and the internal   structure of straight cosmic strings
  We give a brief discussion on the limitations involving the expression mu ={angular deficit}/(8*pi),(G=c=1), which relates the string linear energy density ''mu'' to the conical deficit angle. Then, we establish a new equation between the angular deficit and another physical attribute of the string which shows that the angular deficit is determined not only by the amount of proper matter of the string but also, in a Newtonian sense, by its internal gravitational field. 
F. Dahia