The one-dimensional steady-state convection-diffusion problem for the unknown temperature  of a medium entering the interval  with the temperature  and flowing with a positive velocity  is studied. The medium is being heated with an intensity corresponding to  for a constant . We are looking for a velocity  with a given average such that the outflow temperature  is maximal and discuss the influence of the boundary condition at the point  on the “maximizing” function .
    			                    
    			                 
    		                
    		                
    		            
    			    
    		            
    		                
    		                
    		                
    			                
    			                    
                                       
In this paper we study a discrete Raman laser amplification model given as a Lotka-Volterra system. We show that in an ideal situation, the equations can be written as a Poisson system with boundary conditions using a global change of coordinates. We address the questions of existence and uniqueness of a solution. We deduce numerical schemes for the approximation of the solution that have good stability.
    			                    
    			                 
    		                
    		                
    		            
    			    
    		            
    		                
    		                
    		                
    			                
    			                    
                                       
 
In this paper we study a discrete Raman laser amplification model 
given as a Lotka-Volterra system. 
We show that in an ideal situation, 
the equations can be written as a Poisson system with 
boundary conditions using a global change of coordinates. 
We address the questions of existence and uniqueness of a solution. 
We deduce numerical schemes for 
the approximation of the solution that have good stability.