Valley Networks and the Record of Glaciation on Ancient Mars.

The lack of evidence for large-scale glacial landscapes on Mars has led to the belief that ancient glaciations had to be frozen to the ground. Here we propose that the fingerprints of Martian wet-based glaciation should be the remnants of the ice sheet drainage system instead of landforms generally associated with terrestrial ice sheets. We use the terrestrial glacial hydrology framework to interrogate how the Martian surface gravity affects glacial hydrology, ice sliding, and glacial erosion. Taking as reference the ancient southern circumpolar ice sheet that deposited the Dorsa Argentea formation, we compare the theoretical behavior of identical ice sheets on Mars and Earth and show that, whereas on Earth glacial drainage is predominantly inefficient, enhancing ice sliding and erosion, on Mars the lower gravity favors the formation of efficient subglacial drainage. The apparent lack of large-scale glacial fingerprints on Mars, such as drumlins or lineations, is to be expected.

The effect of formal feedback sessions on test security for a clinical practice examination using standardized patients.

OBJECTIVE: To determine the effects of formal feedback on test security for a clinical practice examination administered to successive rotations over a year's time. METHOD: A seven case clinical performance examination was administered to ten rotations of students throughout an academic year in a required Ambulatory Care Clerkship. Three of the cases were developed at Saint Louis University School of Medicine (SLU); four of the cases were developed by the National Board of Medical Examiners (NBME). Immediately following each examination, the examinees participated in a feedback session for just the three SLU cases: checklists were displayed, and details of the cases were discussed. No feedback on the four NBME cases was provided. Student performance in successive rotations on the three cases in which students were given detailed feedback by the faculty was compared with performance on the four cases in which no feedback was given. SAMPLE: Data were collected from 119 students. RESULTS: The interaction of case and group was not significant, indicating no difference in the trend over the ten groups between the three cases for which feedback was provided and the four cases for which it was not. The results showed no significant increasing trend over the ten rotation groups for either cases where feedback was given or withheld. CONCLUSION: The results suggest that the formal feedback sessions did not pose a threat to test security.

Effects of student gender and standardized-patient gender in a single case using a male and a female standardized patient.

BACKGROUND: In previous studies assessing the effects of student gender, standardized-patient (SP) gender, and their interaction on multiple-station examinations of clinical competence, SP gender was confounded with cases, that is, male SPs were used for some cases and female SPs for others. The authors conducted two studies to investigate the effects of gender on a single case by using a male SP and a female SP for the same case. METHOD: Both studies involved one SP case in a comprehensive clinical evaluation used to assess fourth-year students at the end of a required ambulatory care clerkship at Saint Louis University School of Medicine in 1990-91 and 1991-92. In Study 1, 45 students in four rotations saw the same male SP; 42 students in three other rotations saw the same female SP. In Study 2, 69 students in six rotations were randomly assigned either the male SP (28) or the female SP (41) within the same rotation. For each study, to determine the interaction of student gender and SP gender as well as their main effects, analyses of variance were performed on the students' history-taking and physical examination scores and communication skills ratings. RESULTS: Neither study showed a significant interaction of student gender and SP gender on history taking, physical examinations, or communication skills. CONCLUSION: The findings of both studies suggest that the interaction between student gender and SP gender, unconfounded by case content, had no effect on the students' scores and ratings.

A human heart circulation teaching model using fiber-optic markers.

In teaching anatomy, models are invaluable for reviewing certain concepts, especially those requiring three-dimensionality. Marking points of reference most commonly with numbers, arrows, colored dots, or colored pins is essential for the successful use of these models. However, these marking approaches do not necessarily lend themselves to a "hands on" usefulness for students. Therefore, we have designed a model with fiber-optic reference points. Because of the fragility of models prepared from specimens, we used an acrylic case mounted on a wooden base to protect the human heart circulation model. With the aid of a simple penlight held to the wooden base, the fiber-optic strands illuminate for easy identification of key anatomical points. We use this model in conjunction with a printed self-instructional module.

How medical students learn.

With recent concerns over and attempts to address issues regarding medical students' processes of learning and development of lifelong learning habits, a question often asked is: How do medical students learn in the present medical curriculum? In this study, the authors directly attempt to answer that question--they assess the learning behaviors of 254 students in two medical schools, one with an objectives-based mastery and one with a traditional curricula, and discuss whether the students' adopted behaviors are conducive to the development of effective, analytic, and independent learning. Most students of both medical schools reported very similar effective and ineffective learning behaviors. The students' behaviors were found to dispose them more to analytic learning than to independent learning. Suggestions to restructure the curriculum for better development of students' independent learning habits are proposed.