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Southeast Missouri State University students earning low grades (D or F) have the option of repeating the course. The student's course of action may be to drop out, to change majors, to repeat with the same professor, to try again with a different one, to immediately repeat, or to wait one or more semesters. A purpose of this study was to help students make these decisions. Of 7100 students enrolled in fall 1971 courses, 885 students had repeated 1510 courses at the end of that semester. Six hypotheses were tested. Students were more suc cessful, in general, as additional semesters intervened before repeating. Students repeating with the same in structor had fewer A, B, and C grades. Both trends were relatively weak. EACH SEMESTER some students at Southeast Missouri State University earn one or more "D" or "F" semester course grades. Students who avoid academic suspension are eligible to repeat the course, but decisions to try again are primarily subjective. For example, in addition to the stu dent's ideas he has some access to opinions of other students, to advice from his advisor, and to recom mendations from other faculty members. It is un likely that any consensus exists among either stu dents or staff members on the merit of a particular student repeating a given course. This study is an attempt to provide organized and relevant objective evidence which can be used to improve student de cisions. Some students elect a second enrollment in the following semester; others defer the second attempt for two or three semesters; and some students wait until the semester in which they plan to graduate before repeating a particular course. The number of students who terminate their college experience without recognizing their ability to succeed on a second trial is unknown. Due to the nature of the university's drop-add process, students have limited selection of their instructor. Both attempts may be with the same professor or the second trial may be with a new professor. Some advanced courses which are re quired on a given major are taught by a single pro fessor and no selection is possible. HYPOTHESES As a basis for this study the following guiding hypotheses were developed and tested: 1. Second grades will be better when the course is not repeated during the following semester. Additional intervening semesters will show corresponding improvements in second grades. 2. Second grades will be better when the instruc tor of the repeated course has not taught the student during the previous enrollment. 3. For repeated courses second grades will be related to student classification. Freshmen will not be as successful as sophomores, soph omores less than juniors, and juniors will be less successful than seniors. 4. Most students who have repeated courses will have grade point averages below 2.5. 5. Courses will not normally be repeated more than once. 6. At least 40 percent of those students who re peated courses will have repeated more than one course. This content downloaded from 207.46.13.114 on Thu, 26 May 2016 06:05:01 UTC All use subject to http://about.jstor.org/terms 12 THE JOURNAL OF EXPERIMENTAL EDUCATION METHODOLOGY AND RESEARCH SETTING Unlike studies in which a sample is analyzed and inferences made about the group from which the sample was drawn, this study is fully descriptive of the population of interest. This analysis is based upon data contained in the computer file of completed courses of approximately 7100 students enrolled in fall 1971 courses. Of this group, 885 students had repeated one or more courses as of the end of the fall 1971 session when data were collected. These student records contained some courses from as far back as the fall 1967 semester. There is little doubt but that other courses had been repeated by these active students, but both trials were not a matter of record. The classification of these 885 students and the number of courses repeated by stu dent classification level is below in Table 1. TABLE 1 NUMBER OF STUDENTS AND NUMBER OF COURSES REPEATED BY CURRENT STUDENT CLASSIFICATION LEVEL Number of Courses Current Student Number of Repeated by Student Classification Students Classification Level Beginning fresh men 0 0 Other freshmen 73 101 Sophomores 191 276 Juniors 264 461 Seniors 324 625 Special 7 10 2nd degree 3 3 Graduate 23 34 Senior and grad uate _0 _0 885 1510 To provide additional background information on the repeated courses, another table was prepared. In Table 2 the repeats are summarized by course level?freshman, sophomore, junior-senior, grad uate-undergraduate, and graduate. Of the 1510 courses identified as repeated courses, 1031 are courses considered to be at the freshman level. This does not necessarily indicate that the original "D" or "F" grade was earned while the student was a freshman. While approximately 68 percent of these repeats are at the freshman level, another 16 percent (247 courses) are at the sophomore level, and the remaining repeated courses (approx imately 15 percent) are primarily upper division level courses. The five graduate level repeats were students working on a thesis across two or more semesters. TABLE 2 COURSES REPEATED BY LEVEL OF CLASS Class Courses Level Repeated

Diets in which the chief source of calories was either rice or wheat were formulated by linear programming to meet the requirements of the preschool child for energy, protein and amino acids. Chicken, fish, beef, eggs, whole milk, soy flour and amino acids were used to supplement the cereals to provide the necessary levels of protein and amino acids. Control diets based on egg protein and glucose were formulated to either satisfy or provide an excess above these requirements. The diets were compared in rat feeding tests. Rats fed diets based on wheat supplemented with intact protein or the amino acids lysine and methionine grew at a rate similar to those fed the control diets formulated to just meet the requirements. Rats fed diets based on rice supplemented with intact protein grew at a rate considerably faster than the control diet and also made comparatively faster growth than those fed the wheat diets. The studies indicate that linear programming can be used successfully to formulate human diets based on wheat. However, due to insufficient information on the nutritive value of rice and on the correlation between analytical and nutritive value of rice for humans, linear programming of diets based on rice was not completely successful as measured by uniformity of results. Requirements can be met by fortification of wheat with lysine and possibly methionine with no additional intact protein whereas fortification of rice with lysine alone is not satisfactory. J. Nutr. 103: 179-188, 1973.

There is a widespread belief that some of the rapidly acting pressure control mechanisms such as the baroreceptor feedback mechanism and the reninangiotensin mechanism are also the primary determinant factors for longterm arterial pressure control. But recent theoretical analyses, supported by great amounts of experimental and clinical evidence, have shown that the primary controller of the longterm pressure level is a renal-body fluid volume feedback mechanism for pressure control. This mechanism operates simply as follows: an increase in arterial pressure causes the kidneys to excrete markedly increased quantities of urine. This, in turn, decreases the level of body fluids and eventually decreases the arterial pressure toward normal. However, the short-term arterial pressure control mechanisms obscure this mechanism in acute experiments. Therefore, acute experiments have, until recently, failed to demonstrate the extreme importance and potency of the fluid mechanism. The renal-body fluid volume mechanism for pressure control is a feedback control system of the integral control type that, under appropriate conditions, has infinite capability to return the arterial pressure to its reference pressure level. This reference pressure level is determined by two primary factors: (1) the urinary volume load; and (2) the renal function curve that relates arterial pressure to the urinary volume load. The second of these is usually by far the more important. Therefore, the kidneys play an almost insuperable role in longterm arterial pressure regulation and in hypertension. Nonrenal hypertensive abnormalities can be shown both theoretically and experimentally to cause hypertension by altering either kidney function or fluid intake. Studies indicate that the portions of the kidney most responsible for arterial pressure control are the pretubular segments: the afferent arterioles and the glomerular membrane. Therefore, one can predict that most types of hypertension mechanisms must in one way or another result from primary or secondary abnormal function of one of the pretubular elements of the kidney.

The possibility that the subendocardial region of the left ventricle would exhibit a more anaerobic form of metabolism than the subepicardial region during beta-adrenergic receptor stimulation was examined in the open chest dog. The additional effect of reduced coronary vessel patency was also examined. Beta stimulation was achieved by administering isoproterenol intravenously for 4 minutes, after which time a transmural tissue sample was procured from the beating left ventricle for estimating outer and inner wall levels of pyruvate, lactate, and tissue water content. Results in the animal with a normal coronary circulation revealed relatively higher inner wall levels of both pyruvate and lactate, but no outer to inner wall difference in the lactate/pyruvate ratio. An absolute increase in tissue pyruvate was noted in both regions. Results in the animal with reduced coronary vessel patency revealed a relatively higher inner wall level of lactate, but not pyruvate, and a higher lactate/pyruvate ratio in the inner than the outer wall. An absolute increase in tissue lactate was noted in both regions. Tissue water content was uniform in all studies. These findings suggest that, although the subendocardial region may be the site of greatest metabolic activity during beta-adrenergic receptor stimulation, the presence of a normal coronary circulation insures against the development of a more anaerobic form of metabolism there. However, a reduction in coronary vessel patency does predispose the subendocardial region to a more anaerobic form of metabolism during beta-adrenergic receptor stimulation.

CHANGES in the metabolism of phenylalanine have been related to altered homeostasis of brain enzymes and mental deficiency in mammals1. Little is known, however, about the situation in fish, and we wish to describe the chronic effects of the pesticide dieldrin on these metabolic pathways in the rainbow trout (Salmo gairdneri). According to the National Pesticide Monitoring Program2, this is one of the most prevalent pesticides in the aquatic environment, having been found in 93% of fish samples from across the United States in concentrations of 0.01 to 1.6 µg/g (p.p.m.).