Google and I have 464 down as possibly:
Jan Klusak
Variations on a Theme by Gustav Mahler (1962)
Correct Mr. Daniel! One of the first Czech serial works. Here is something of what the composer himself says of it:
"I started contemplating the composition of orchestral variations on a prominent theme from the Adagietto of Mahler’s Fifth Symphony in the Spring of 1960. I imagined a piece of music whose fabric would disintegrate and atomize in the manner of Webern and his followers, and yet something universally musical and familiar would constantly emerge from it. It would be very hard to discern traces of some ordinary music fading away before our very eyes. It would be like someone drowning and resurfacing every so often to yell for help, after which there would just be the roar of water and other sounds of nature. Or like some creature battling death and trying to say or do something meaningful in its final throes, but with no strength left. Incoherence, hesitation, suffusion with blood were intended to be part of the composition from the outset, and I really do think they are present. Or like when we find a fragment of something that had once been part of a whole, and now we strenuously piece it together; I say strenuously because strenuousness and laboriousness, and particularly vain and abortive laboriousness, were also part of the programme of the Variations from the outset.
"So what sort of composition are the Variations? They are Jewish, above all: on account of their Old Testament, existentialist and unransomed attitude, also their Mahleresqueness, as well as their overall atmosphere, which I can’t rationally substantiate, but you can feel; also because they are connected with my father, and finally because they are arranged according to numbers that are significant in the Kaballah (this wasn’t intentional, however, I only discovered it afterwards) [...] Another characteristic of the Variations is that they are to do with content; I’d almost call them a programme composition in the Berliozian, Brucknerian, Mahlerian or Schoenbergian sense, because apart from being music, they also have an extra-musical significance – they have their own ideology. During the first days after finishing the score I wrote down a number of headings: Variations I-II – longing for ideal beauty, a bit ostrich-like; a little glass castle, fairy tale. Variation IV– levity, profligacy; whereas the previous two variations hid themselves from reality, this one is flightily reconciled with it and lives in it without a care or remorse; cynicism. Variation VI – word of command, signal. Variations VII-VIII – mysterious stampede. Variations IX-X – imminent storm. Variation XII – horror of life, and sadness that most people have no notion of such a thing. Variation XIII – extreme hysteria. Variation XIV – beneath the wheels of the world. Variation XV – faint rustles of objects; the impenetrability of things. Variation XVI – extreme loneliness. That probably suffices. It’s obvious, I hope, that the Variations on a Theme of Mahler are a romantic work and they are to be performed romantically [...] I also regard them as a Secessionist and Expressionist composition, written sixty years after the period when those styles were current."
Our extract of course comprises the end of the statement and the beginning of the first variation.