X-Message-Number: 27892
Date: Mon, 1 May 2006 20:04:50 -0700 (PDT)
From: Doug Skrecky <>
Subject: 225'th update on fly longevity experiments

     This is the 225'th update of my fly longevity experiments. Average
 temperature was 23.9 C during this run. Estimated maximal longevity using
 the formula (363 - T*11.2) is 95 days.
     In run #91 substituting distilled water for tap water was found to
 decrease survival. This run retests this to check if it was just a chance
 finding, and also examines some other sources of water.
     If the two bottles using Exact distilled water in this run are
 averaged together they slightly underperformed tap water, so this could
 be interpreted as weak confirmation. Penta (reverse osmosis) water, which
 also had a very low solids content (<2ppm) also slightly underperformed.
     Tap water that was boiled and concentrated until only 9.3% was left
 performed slightly better than fresh tap water. A surprising benefit was
 found for Aquafina water, which was treated with reverse osmosis, but had
 a higher solids content (<10ppm) than Penta water.
     What does this all mean? Both Exact and Penta water have very low
 solids content, but no rational tieing this to a slightly reduced
 survival can be formulated. However both Exact and Penta would probably
 also have a reduced heavy water content. As deuterium is known to exert
 some biological effects at low concentrations, then perhaps this might be
 the active ingredient. The next run will investigate the effect of
 supplemental heavy water on longevity.
     The unexpected benefit of Aquafina water relative to tap water may
 reflect a reduced pathogen content. The boiled water also suggests this
 explanation. Further testing with both heated tap water and Aquafina have
 been scheduled.

 Run #225                  Percent Survival on Day
 supplement          9  19  26  35 49 64 73 82 93 105 113
 ________________________________________________________
 tap water #1      100 100 100 100 76 35 24 10  0   -   -
   "       #2       97  94  92  81 58 31 22  8  0   -   -
 Aquafina #1       100  95  95  82 71 45 32 18  5   3   0
   "      #2        98  91  83  74 57 41 29 17  5   2   0
 90.7% boil-off #1 100 100  94  84 56 28 16  6  6   0   -
   "            #2 100  95  80  64 49 23 15  5  3   0   -
 Exact #1           97  92  84  76 60 35 27 19  5   0   -
   "   #2           97  97  87  80 51 15  3  0  -   -   -
 Penta #1          100  97  97  77 61 26 16  7  3   0   -
   "   #2          100 100  93  80 55 30 13  0  -   -   -

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