The effects of intracanopy lighting on cowpea production

Utilizing a combination of above-canopy and intracanopy lighting may prove highly beneficial in a Lunar Controlled Ecological Life Support System (LCELSS) as a means of increasing volumetric efficiency of plant growth. Intracanopy lighting was not found to be detrimental to plant tissue and production per plant when cowpeas were grown using sand culture. Specifically, intracanopy lighting did not adversely influence leaf area, dry mass, or wet mass production. Although no significant differences were found when 25% of the lighting was placed intracanopy, this is important because it indicates that there is potential in saving space for controlled growth systems. The use of intracanopy lighting would allow plant trays to be "stacked" closer, thereby increasing volumetric plant density.

Effect of strength training on orthostatic hypotension in older adults

PURPOSE

This preliminary study attempted to identify the frequency of orthostatic hypotension (OH) in community dwelling older adults who volunteered to participate in an 8-week, heavy-resistance, strength-training program. It also assessed the effect of the strength-training program on OH.

METHODS

From a larger study (n = 53) on high-resistance strength training in older adults (mean age 71.4 +/- 6.6 years), a subset of subjects (n = 24), mean age 71.0 +/- 5.8 years, was evaluated who met at least one criterion for OH. All subjects were tested for resting blood pressures (BP) and heart rates (HR) in the supine, sitting, and standing positions. Also noted was their response to orthostatism in rising from a cot after 10 minutes and rising from a chair after 5 minutes. The subset was not different from the overall group in gender ratio, age, or effect of medication on BP. The treatment was an 8-week strength-training program at 80% of their one repetition maximum.

RESULTS

Significant changes (P < 0.05) were shown in supine diastolic BP (+3.2 mm Hg), sitting systolic BP (-3.9), and standing HR (+4.9 beats per minute). In response to the orthostatic challenge, significant (P < 0.05) improvements were shown in systolic BP (+9.7 mm Hg), diastolic BP (+4.7), and HR (+3.2 beats per minute) for the rise from chair, and in diastolic BP (+6.7 mm Hg) rise from the cot.

CONCLUSIONS

These data show that OH is not uncommon (45%) in community dwelling older adults. A strength training program in older adults has little effect on resting BP, but elicits a positive adaptation to an orthostatic challenge.