Athel Cornish-Bowden wrote:
>I recently made an informal poll of several colleagues about whether
>they preferred to write control coefficients and elasticities in the
>logarithmic form, i.e.
>>dlny/dlnx
>>or without logarithms, i.e.
>>(x/y)(dy/dx)
>>(In both cases please assume that the derivatives are printed or written
>in a nicer form than is possible in a plain text message.)
>The question was mainly posed in the context of understandability for
>readers of papers or students of metabolic control analysis with limited
>mathematical expertise, but it may also have wider implications.
>>The results were more varied (with much more varied reasons given for
>the different opinions) than I expected, so it is clear that this is not
>a subject with much unanimity at present, and that it may benefit from
>wider discussion. I shall not, therefore, try to summarize the views
>already received, but will simply pose the same question to the News
>Group, and hope that those who have already given a private response
>will also give a public one.
>>My own view, incidentally, was (before asking anyone else) that the two
>forms were equivalent and equally easy for students to understand (at
>least for those able to cope with the matrix algebra involved in
>metabolic control analysis), but that the first was usually preferable
>for typographical reasons.
>>Athel Cornish-Bowden
My experience is that undergraduate students without a mathematicas
background find the form without logarithms much easier to understand - it
is a natural scaled slope and easy to explain to biochemists, whereas the
log form seems to some of them to be some unfathomable mathematical trick.
But I agree that the log form is more concise.
It is also my experience that the use of matrix algebra is a guaranteed way
to lose a general biochemical audience. Since a lot of what we are all
trying to do at the moment is to persuade the mainstream metabolic control
community to adopt control analysis, we should strenuously keep things as
simple and non-mathematical as we can. In material for general consumption
we should be using non-log equations instead of log equations, simultaneous
equations instead of matrix equations, and (wherever possible) words and
descriptions instead of equations of any sort. Once people are interested
they will need the maths, but they have to become interested first.
Martin Brand
Martin D. Brand
Department of Biochemistry, University of Cambridge
Tennis Court Road, Cambridge CB2 1QW UK
phone: +44 1223 333648, fax: +44 1223 333345
Internet: http://www.bio.cam.ac.uk/dept/biochem/brand/
