I have a recurent problem with Inkscape for which I am desesperate to find a solution. I use Inkscape for work, and I often have to import curves from .ps or .pdf file to then fit them into a schematic or a scale. The problem is that I often have no control on the ps/pdf file, and if I must significantly rescale the curve, it exhibit different stroke widths. I can easily create another path using

I have included a example here https://mega.nz/#!kcMkyDhS!LYtBgMp1qKZIKLNz8JRPqTL4MdFoA88ayuK0gDed4yg, in hope it helps.
Thanks a lot in advance to anyone who would suggest a solution, this problem have been annoying me for a long time now.