The authors are advised to submit a revised manuscript. The authors need to fully address all the comments made by the reviewers. We note that the responses made by the authors which were posted seemed to be more of defending what they did but without stating how they will address the comments made.

If there are some comments which the authors are of the opinion that they should not be considered in revising the paper, the authors will have to provide valid reasons.

The revised paper may be submitted to the Reviewers if we are not certain that comments made have been adequately addressed.

The authors should revise the paper in line with the comments submitted by the Editor on 26 May 2015

I have highlighted a few corrections that need to be made when the authors submit the paper to be published. The authors need to submit figures that clear for reproduction