Recording Leaf Movements with a Strain Gauge

Lightweight strain gauge sensing unit for recording circadian leaf movements in space environmen

Effect of space environment on circadian rhythms of plants, for the purpose of defining and verifying an experiment suitable for use in a biosatellite final report, sep. 1, 1964 - feb. 28, 1965

Space environment effect on circadian rhythms of plants for use in biosatellit

Effect of Space Environment on Circadian Rhythms of Plants, for the Purpose of Defining and Verifying an Experiment Suitable for Use in a Biosatellite Semiannual Report, Sep. 1, 1963 - Mar. 1, 1964

Space environmental effects on circadian rhythms of plants - plant data for use in biosatellite

The effect of ultradian and orbital cycles on plant growth

In a series of experiments using sugar beets, researchers investigated the effects of varying cycles lengths on growth (0.37 hr to 48 hr). Each cycle was equally divided into a light and dark period so that each treatment regardless of cycle length received the same amount of light over the 17 weeks of the experiment. Two growth parameters were used to evaluate the effects of cycle length, total fresh weight and sucrose content of the storage root. Both parameters showed very similar responses in that under long cycles (12 hr or greater) growth was normal, whereas plants growing under shorter cycle periods were progressively inhibited. Minimum growth occurred at a cycle period of 0.75 hr. The yield at the 0.75 hr cycle, where was at a minimum, for total fresh weight was only 51 percent compared to the 24 hr cycle. The yield of sucrose was even more reduced at 41 percent of the 24 hr cycle

Closed culture plant studies: Implications for CELSS

Arabidopsis plants were grown in closed cultures similar to those used in space experiments. A shift in metabolism from photosynthesis to respiration is indicated by the accumulation of CO2 in the culture atmosphere. Reproductive growth is suppressed. Plant growth and development is apparently related to the atmospheric volume available to each plant. The implications of these findings to closed ecological systems are given: (1) there is a need for an open culture having ample gas exchange, (2) CO2 levels must be maintained within prescribed limits, (3) the minimum atmospheric volume required for each plant is dependent on the precision of the gas monitors and of the subsystems used to maintain appropriate levels of various atmospheric components, and (4) volatiles such as ethylene and terpenes emanating from plants be monitored and reduced to benign concentrations

KINEMATIC CHARACTERISTICS OF OPPOSITE-FIELD HITTING

Baseball is one of many popular sports in which the cen tral event involves a collision between an implement and a ball. It is generally agreed that hitting a baseball is one of the more difficult skills to learn in sport (Breen, 1975; Williams & Underwood, 1971). In addition to the habitual goal of maximal transfer of momentum to the ball, the batter frequently faces problems of directional guidance, due to certain strategic and mechanical requirements. The nature of the contact surfaces, the high velocity of pitched baseballs and the variety of ball trajectories combine to increase the difficulty of the task

Power and Strength Profiles of Elite 16-20 Years Old Ice Hockey Players

The sport of ice hockey has received considerable attention from researchers interested in the energy systems supporting high level competition. For example, Bonen and Babincau, 1977, Ferguson. Marcotte and Montpetit, 1969, and Montpetit, Ferguson and Marcotte, 1971 investigated the V02 max. of hockey players using various measurement and statistical prediction techniques. Other researchers have speculated that the nature of ice hockey requires high levels of anaerobic energy and the ability to recover quickly from a bout of high intensity exercise (Green, Bishop, Houston, McKillop, Norman and Stothart, 1976; Montpetit, Binetto and Taylor, 1969; Smith, Wenger and Quinney, Sexsmith and Steadward, 1980, Watson and Sargeant, 1986). At present, there is little evidence of attempts to correlate physiological power to mechanical power of ice hockey players. Since skating, which is central to the game of hockey, requires a great deal of leg power, this variable would seem to be a basic prerequisite of effective performance. The purpose of the present study, therefore, was to investigate power and strength relationships in elite 16-20 year old ice hockey players. More specifically, an attempt was made to describe the relationships between various anaerobic power measures and the mechanical power exhibited by the leg muscles during a vertical jump task

IMPACT FREQUENCY VALIDATION OF HEAD IMPACT SENSOR TECHNOLOGY FOR USE IN SPORT

Head impact frequency has been identified as a contributing factor to long-term trauma experienced by the brain. A peak linear acceleration greater than 20g has been proposed as defining a single impact. The purpose of this study was to examine the accuracy of a single head impact sensor to identify 209 impacts under short

MEASUREMENT ACCURACY OF HEAD IMPACT MONITORING SENSOR IN SPORT

Head injury and brain trauma exposure in sport have been recognized as potential contributors to long-term neurological disorders. As a result sensors have been proposed as an impact severity monitoring tool for on-field measurement of head accelerations. The purpose of this study was to characterize the accuracy of a head impact monitoring sensor system. Peak acceleration responses from a Smart lmpact Monitor (SIM) sensor were compared against reference sensors from a Hodgson-WSU headform. The headform with SIM was impacted for 7 impact conditions and 3 inbound energies. Moderate to strong positive correlations were found between the SIM and reference sensors for all impact conditions. At higher inbound energy the SIM overestimated, suggesting that under higher risk conditions the SIM represents a conservative tool in identifying dangerous impacts