The VCO2-VO2 (alveolar CO2 output-alveolar O2 uptake) relationship (V-slope) during increasing work rate (ramp) cycle ergometer exercise has two approximately linear components: a lower component slope (S1) with a value of about 0.95 and a steeper, upper component (S2). We examined the effect of muscle glycogen depletion (protocol 1) and the rate of increase in work rate (ramp rate) without muscle glycogen depletion (protocol 2) on S1 and S2. In protocol 1, ten healthy men with a mean age of 31.4 years (S.D. 6.2) were studied on each of 3 days (days 1 and 3 were control days). They performed a ramp exercise test to maximum tolerance and steady-state tests at rest, during unloaded pedalling and at two constant work rates below their anaerobic threshold (AT). To deplete muscle glycogen before the test on day 2, the subjects performed 2 h of very heavy cycle exercise on the preceding day and fasted overnight. S1 was reduced on day 2 (0.79 compared with 0.95, P less than 0.001), as was the VCO2-VO2 slope derived from steady-state measurements (0.81 compared with 0.99, P less than 0.001), but AT and the slope difference (S2 - S1) were unchanged. In protocol 2, seven healthy men with a mean age of 20.6 years (S.D. 2.4) performed ramp tests at three different rates of increasing work rate (15, 30 and 60 W min-1), each ramp rate being performed twice in random sequence. The ramp rate did not affect S1 but S2 was steeper with the faster rates of work rate increase (1.27, 1.43 and 1.63, respectively, P less than 0.01). Our findings support the concept that the lower component of the V-slope plot (below AT) represents muscle substrate respiratory quotient (RQ) while the difference between S1 and S2 reflects 'excess CO2' derived from bicarbonate buffering of lactic acid.

Urban Canada goose (Branta canadensis) populations have grown rapidly during the past three decades. This paper reviews short-term and long-term urban goose management techniques, and using data for the Twin. Cities of Minnesota, assesses the potential utility of habitat modification. Ninety-four percent of Twin Cities damage complaints occurred during the brood-rearing period, 5% in fall, and >1% in spring and winter. The potential for reducing goose damage by altering nest habitat is insignificant, brood-rearing habitat high but expensive, and fall and winter habitat low and also costly. Fences effectively thwart flightless geese but can entrap birds leading to starvation. Cost projections for programs limiting the Twin Cities summer population at 25,000 were $125,000/year for relocation, $325,000/year for processing for human consumption, $12.3 million/25 years for wire fences, $33.9 million for tall grass prairie, and $1.8 billion for ground juniper (Juniperus spp.). Human preference for savanna and the fear of urban crime associated with dense vegetation may hamper implementation of goose habitat modification.