Very haunting and beautiful... I'm not necessarily sure what purpose this piece was written for, but from the sound of it it invokes a sense of dolorousness. If this was your target, you have certainly done well, and this is a wonderful piece indeed!
Nevertheless, the piece is not bereft of qualms. My first qualm lies in measure 10, in the third beat, where the chord is a rather oddly structured major V chord. The held D in the bottom Viola divisi section clashes with the rest of the orchestra on that particular chord. If your intention is to hold the I note through that particular section, then I would suggest that you do the same for the lower instruments as well. If not, consider revising the chord.
The next qualm of mine: the fermata at 27. I am at disagreeance with this particular chord; why end on this? This is just a personal opinion (in no way do I mean to interfere with your composition), I think a Bb major seventh chord would create more tension and longing for the next note. Another suggest I might add would be a possible diminuendo toward this fermata, which may also assist with providing tension.
Now, on to what I like: the motifs which you mentioned earlier are fascinating... it is indeed good that you wrote them down. As Shostakovich once said, "Whatever you have in your head, write it down; the mind is a sensitive vessel." You intertwined the motifs quite well within the piece. The syncopated theme in the introduction and end also do well.
I have one more suggestion: tie the pedal notes. This one is the least important of the suggestions, though, but do consider this.
Once again, this is a beautiful and haunting piece, and I would love to hear it performed.
