Effect of ascent protocol on acute mountain sickness and success at Muztagh Ata, 7546 m

Bloch, Konrad E., Alexander J. Turk, Marco Maggiorini, Thomas Hess, Tobias Merz, Martina M. Bosch, Daniel Barthelmes, Urs Hefti, Jacqueline Pichler, Oliver Senn, and Otto D. Schoch. Effect of ascent protocol on acute mountain sickness and success at Muztagh Ata, 7546 m. High Alt. Med. Biol. 10:25-32, 2009.-Data on acclimatization during expedition-style climbing to > 5000 m are scant. We evaluated the hypothesis that minor differences in ascent protocol influence acute mountain sickness (AMS) symptoms and mountaineering success in climbers to Muztagh Ata (7546 m), Western China. We performed a randomized, controlled trial during a high altitude medical research expedition to Muztagh Ata. Thirty-four healthy mountaineers (mean age 45 yr, 7 women) were randomized to follow one of two protocols, ascending within 15 or 19 days to the summit of Muztagh Ata at 7546 m, respectively. The main outcome measures, AMS symptom scores and the number of proceeding climbers, were assessed daily. Mean +/- SD AMS-C scores of 16 climbers randomized to slow ascent were 0.06 +/- 0.18, 0.26 +/- 0.08, 0.41 +/- 0.45, 0.53 +/- 0.77 at camps I (5533 m), II (6265 m), III (6865 m), and the summit (7546 m), respectively. Corresponding values in 18 climbers randomized to fast ascent were significantly higher: 0.17 +/- 0.23, 0.43 +/- 0.75, 0.49 +/- 0.36, and 0.69 +/- 0.54 (p < 0.008, vs. slow ascent in regression analysis accounting for weather-related protocol deviation). Climbers randomized to slow ascent were able to ascend according to the protocol without AMS for significantly more days than climbers randomized to fast ascent (p = 0.04, Kaplan-Meier analysis). More climbers randomized to slow ascent were successful in reaching the highest camp at 6865 m without AMS (odds ratio 9.5; 95% confidence interval 1.02 to 89). In climbers ascending to very high altitudes, differences of a few days in acclimatization have a significant impact on symptom severity, the prevalence of AMS, and mountaineering success. ClinicalTrials.gov Identifier NCT00603122.

Unanticipated Partial Behavioral Reflection: Adapting Applications at Runtime

Dynamic, unanticipated adaptation of running systems is of interest in a variety of situations, ranging from functional upgrades to on-the-fly debugging or monitoring of critical applications. In this paper we study a particular form of computational reflection, called unanticipated partial behavioral reflection, which is particularly well-suited for unanticipated adaptation of real-world systems. Our proposal combines the dynamicity of unanticipated reflection, i.e. reflection that does not require preparation of the code of any sort, and the selectivity and efficiency of partial behavioral reflection. First, we propose unanticipated partial behavioral reflection which enables the developer to precisely select the required reifications, to flexibly engineer the metalevel and to introduce the meta behavior dynamically. Second, we present a system supporting unanticipated partial behavioral reflection in Squeak Smalltalk, called Geppetto, and illustrate its use with a concrete example of a web application. Benchmarks validate the applicability of our proposal as an extension to the standard reflective abilities of Smalltalk.