Nature is a weekly scientific journal. In addition to their normal articles, they also publish a short science fiction story every issue in the Futures column.
I don't actually know if this is a higher-tier rejection or just a nicely written standard form. Please edit appropriately if you can figure it out.
Thank you for submitting your story XX to Futures. However, I regret to tell you that I cannot offer to publish your piece on this occasion. Futures attracts a very high number of submissions — around ten times the number of stories that we can actually publish — so I am obliged to make difficult decisions.
I know that this will be disappointing but I hope that it will not discourage you from submitting to Futures again.