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This report presents the results of a study undertaken to test the possibility that pre-existing attitudes could explain the previously reported association between fitness improvement and attitudes and self-confidence. Recruits from four Marine Corps basic training platoons (n=265) provided data for the study. Scores on the standard physical fitness tests showed that one platoon had substantially above average fitness improvement and another substantially below average improvement. A comparison of these two platoons on attitude and self-esteem measures showed that the high improvement platoon had more positive attitudes toward the Marine Corps and higher self-esteem. The attitudes included greater acceptance of the need for authority and discipline, greater identification with the Marine Corps, higher commitment to achieving and maintaining high levels of performance, and greater satisfaction with the Marine Corps. (JD)

Physical training is a significant element of Marine Corps basic training which may affect nonfitness basic training outcomes in addition to improving fitness. If so, physical training side effects should be considered when designing and evaluating physical training programs. This study capitalized on naturally occurring platoon differences in fitness outcomes to classify basic training platoons into relatively high and low improvement groups. The high improvement group had better attitudes toward the Marine Corps, greater perceived self-improvement, and performed better during basic training. The groups had comparable illness rates during basic training, but there was more medical attrition and overall attrition in the high improvement group. The groups did not differ with regard to Fleet Marine Force promotion or attrition rates. These findings demonstrate that physical training programs may indeed influence nonfitness basic training outcomes. Additional research is needed to verify that physical training differences actually cause nonfitness basic training outcomes, to determine whether these side effects are large enough to be of practical importance, and to identify specific aspects of physical training programs that are important for promoting nonfitness basic training objectives. (Author)

The increasing use of radar systems as remote sensors of ice thickness has revealed a lack of basic data on the microwave properties of fresh-water ice. A program, in which the complex dielectric constant was measured for a series of ice samples taken from the Great Lakes, is described. The measurements were taken at temperatures of -5, -10, and -15 C. It is noted that the ice has considerable internal layered structure, and the effects of the layering are examined. Values of 3.0 to 3.2 are reported for the real part of the dielectric constant, with an error bar of + or - 0.01.

Description of the design and operation of two new short-pulse radar systems developed for use aboard aircraft for remote profiling of lake ice thickness. The principle of operation is based on the fact that the return signal is composed of a pulse return from the top of the ice and another, delayed in time, from the ice-water interface. The delay time between these two pulses directly gives the ice thickness when allowance is made for the slower RF propagation through the ice. The two systems are the S band and the C band systems, and their comparative merits are discussed.

This paper describes helicopter-borne measurements of ice thickness in Lake Superior, Lake St. Clair, and the St. Clair river as part of NASA's program to develop an ice information system. The profiler described is a high resolution, nonimaging, short pulse radar, operating at a carrier frequency of 2.7 GHz. The system can resolve reflective surfaces separated by as little as 10 cm and permits measurement of the distance between resolvable surfaces with an accuracy of about 1 cm. Data samples are given for measurements both in a static (helicopter hovering), and a traverse mode. Ground truth measurements taken by an ice auger team traveling with the helicopter are compared with the remotely sensed data and the accuracy of the profiler is discussed based on these measurements.

Using a radar system with high range resolution, it was shown that measurements of snow and ice thickness are feasible with an accuracy of better than 3 inches. In addition, the water equivalent of the snowpack can be estimated, given a single surface measurement of the snow depth. Discontinuities in density were also detected and their location determined by inspection of the radar returns. The remote measurement of layer thickness is described. The system was designed for eventual incorporation into a light aircraft.