I've looked at your listings, and, unfortunately, the listings were almost entirely comprised of a sampling of the literature regarding relaxation or biofeedback. As indicated in prior listings (above), this is VERY different from Zen Meditation. Relaxation may be one of the sequellae of Zen meditation, but it is not a central focus of practice, nor is it a topic written about in the extensive Zen literature.
The one study you list using meditation by Jon Kabat-Zinn, (a molecular biologist from U Mass Med center who runs a stress reduction program using Yoga and a variation on Vipassana), was a non-randomized single group pre-post design, which showed a reduction in anxiety, similar to that achieved with most therapies, or, in some studies, similar to changes that occur over time without therapy.
Most of us know that meditation is extremely valuable. We need to begin demonstrating it through good solid research, as advocates of biofeedback have done!
Thanks for the reminder of the paucity of the meditation literature, and the need to emulate our "cousins" in other applied areas of psychotherapy.