Alan E. Treloar

Comparison of indirect and direct methods of measuring arterial blood pressure.

Direct and indirect determinations of blood pressure have been recorded in 70 human subjects. Statistical analysis of the results is presented. A frequent discrepancy between direct and indirect readings is evident with the drift of the latter falling increasingly below the direct measurement as blood pressure rises. The greatest discrepancy is found in the young hypertensive subject and the possible clinical implications of this finding are discussed. An attempt is made to explain some of the factors contributing to the variable error by which auscultatory readings underestimate the true intraarterial pressure.

Changes in menstrual cycle length and regularity after use of oral contraceptives.

This is an analysis of changes in menstrual cycle length and regularity occurring for a group of 211 women who had discontinued use of oral contraceptives. The analysis is based on prospectively recorded histories from the Menstruation and Reproduction History Program. Post‐pill menstrual cycle length and regularity are compared with pre‐pill averages. In the first post‐pill cycle, there was an average increase of 6 days in cycle length. In subsequent cycles, however, cycle length and regularity were comparable to pre‐pill norms in most cases.

VARIATION OF THE HUMAN MENSTRUAL CYCLE THROUGH REPRODUCTIVE LIFE

30 years of data directed to the study of the temporal characteristics of the human menstrual cycle and some of its associated phenomena are presented. Approximately 2700 record-keeping collaborators and their daughters were enrolled. Only records of greater than 6 months uninterrupted recording are included. A record of all surgery illness or medication which might influence menstruation was recorded as well. Age of the patient and age since menarche are recorded. By 1961 this study had accumulated 25825 person-years of menstrual experience with 2750 intervening pregnancies. Justification of the belief that women normally vary in menstrual interval around a value of 28 days was unsupported. Each woman has her own central trend and variation which changes with age. The menstrual interval should be expected to average within a few days of 28 when assembled in large groups. Variation as opposed to regularlity is the rule in the menstrual cycle. The early and late years of menstrual life have the greatest variation in pattern of both long and short cycles and tend to mirror each other. The middle years of menstruation is characterized by linear change in both central tendency and variation; falling 2-3 days in this age span. Variation in menstrual cycle reaches its minimum at around 36 years of age. Determining the pattern of variation in menstrual history for anticipated intervals needs further study. The practice of birth control through the use of rhythm methods alone must introduce elements of uncertainty which are serious problems.

A Comparison of Dockage Assessments with Total Screenings 1

The correct esthnation of the amount of for¢ign substances present in a carlot of wheat as it arrives at the ~erm~,nal market for disposal to buyers presents a problem of considerable importance to the producer, the seller, and the buyer, who, in most cases, is the miller. The reports on dockage and foreign material Other than dockage presented by the state grain inspection departments and licensed inspectors, in accordance with the directions of the Handbook of Official Grain Standards, represent careful endeavors toward the estimation from samples of the proportions of good sound wheat, straw, foreign grains, etc., present in the entire bulk sampled. The economic importance of a correct estimation of dockage in wheat arriving at terminal markets in the United States becomes clear from the fact that an average error of only o. S °flo less estimated dockage than might be actually found from cleaning all the wheat would result for the average post-war crop in a gain to the sellers and a 10ss to the buyers of approximately 4. e million bushels of grain t)er annum. In accordance with official statements, material thus classed as dockage should correspond closely to the screenings derived from the bulk grain by the customary cleaning machinery used in commercial mills. The separators of this class in use at the Minnesota State Testing Mill have been described in Bulletin e3 of the Minnesota State Department of Agriculture, and represent standard cleaning machinery of modern milling practice. The screenings from the receiving and milling separators have been grouped as one unit in this stud.y and will be referred to as total mill screenings.