What does this mean, "We recommend that you consider submission to an alternative venue"? Recently, after submitting a manuscript for publication, I received the following response:


  Your manuscript, referenced below, has been considered for publication in XXX: "Article Title" 
  Unfortunately, this manuscript on a fundamental topic does not fall under the range of topics that are covered by XXX, which focuses on the applied physical sciences. We recommend that you consider submission to an alternative venue.


My question is, what is the meaning of the sentence "We recommend that you consider submission to an alternative venue". To me, it sounds like a terse "good luck with that!" sign-off. However, that's an odd sentence, as they usually just write "no" in those cases. Does this imply anything particular about my submission?
From what you've said by itself, it's ambiguous. That is, if your paper really is on a topic not usually covered by that journal, then their remark is completely bland, just meaning what it says. If, at the other extreme, you are pretty sure that your paper's topic is exactly what is covered in the journal, then, yes, their "recommendation" is just a polite form of rejection.

If you are a beginner at this, it is possible that your understanding of what your own paper is about may have some quirks or limitations, or you've presented it in a way that dis-served you, or you've presented it in a way that confused or mis-directed the editors/referee, etc. 

For example, giving inappropriate/inaccurate keywords can get a paper sent to an inappropriate referee, who may think the paper is misguided, while if you'd given different keywords, a different referee might think it was mainstream and wonderful.

Similarly, unfortunate choices in title, abstract, and introduction can set things off down the wrong path. Getting an opinion from an experienced person about the actual appropriateness of your paper for that venue is necessary before it's possible to understand the situation.