Gastrointestinal function during the menstrual cycle.
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Digestive System Physiological Phenomena↗
Biomedical subjects
L Simmons
Publications and source records attributed to L Simmons.
A cost-benefit analysis of demand for food.
Laboratory studies of consumer demand theory require assumptions regarding the definition of price in the absence of a medium of exchange (money). In this study we test the proposition that the fundamental dimension of price is a cost-benefit ratio expressed as the effort expended per unit of food value consumed. Using rats as subjects, we tested the generality of this "unit price" concept by varying four dimensions of price: fixed-ratio schedule, number of food pellets per fixed-ratio completion, probability of reinforcement, and response lever weight or effort. Two levels of the last three factors were combined in a 2 x 2 x 2 design giving eight groups. Each group was studied under a series of six FR schedules. Using the nominal values of all factors to determine unit price, we found that grams of food consumed plotted as a function of unit price followed a single demand curve. Similarly, total work output (responses x effort) conformed to a single function when plotted in terms of unit price. These observations provided a template for interpreting the effects of biological factors, such as brain lesions or drugs, that might alter the cost-benefit ratio.
Animals↗
Chickenpox in young anthropoid apes: clinical and laboratory findings.
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Animals↗
G-band patterns, hemoglobin, and transferrin types of the bharal: chromosomal evolutionary relationships with sheep and goats.
G-band patterns of the bharal (Pseudois nayaur), 2n = 54, were compared with those of wild sheep (Ovis dalli stonei), 2n = 54, and the Persian wild goat (Capra hircus), 2n = 60. Patterns of the longer segments of the biarmed chromosomes of Pseudois were similar to those of the longer biarmed segments of Ovis, whereas the shorter segments differed. Biarmed chromosomal segments had G-band homologies with specific acrocentric autosomes of Capra and were ranked as follows in descending order of relative lengths: Pseudois 1:4/13; 2:1/27 and 3:3/29; and for Ovis 1:1/5; 2:3/10 and 3:4.9. Arm ratios and relative lengths of the biarmed chromosomes were compared. The Y chromosome of Pseudois is a small biarmed chromosome that resembles those of Capra and Ovis. Hemoglobin B was observed in the bharal and was indistinguishable from Hb B of Ovis using starch-gel electrophoresis. The transferrin "zone pair" of Pseudois migrated more slowly in starch-gel electrophoresis than do any of the known transferrin types in sheep and goats. We refer to this transferrin as Pseudois Tf A. The biarmed formations of Pseudois and Ovis are discussed in relation to karyotype evolution and possible speciation.
Animals↗
Removal of impacted third molars by oral/maxillofacial surgery and general dentistry residents.
The post-operative symptoms of patients who had undergone third molar extractions by Oral/Maxillofacial Surgery (OMS) residents were compared with those of patients whose extractions were performed by General Dentistry (GD) residents. The OMS group had more extractions per visit and were more likely to use intravenous sedation than the GD-treated group. No significant differences were found when the provider groups were compared by post-operative symptoms such as osteitis, infection, trismus, or paresthesia/dysthesia. The pain relief due to postoperative analgesics during the immediate 12-hour period was higher for patients treated by GD residents. Multiple regression analysis revealed that this difference was due to the number of teeth extracted and the complexity of the surgical procedure, independent of type of provider.
Adolescent↗
The effects of diisopropyl phosphorofluoridate (DFP) on inter-response time and circadian patterns of lever-pressing in rats.
Rats were injected with saline, 1.0 mg/kg or 2.6 mg/kg of diisopropyl phosphorofluoridate (DFP). Three days later the animals were placed in cages in which they could press a lever to obtain their entire daily ration of food. The time of day at which responses occurred and the time between successive responses were recorded over a six day period to determine the circadian pattern of lever-pressing and the distribution of inter-response times (IRTs). The saline injected rats exhibited a normal nocturnal pattern of feeding, while both DFP treated groups exhibited a significantly greater tendency to eat during the day. Analysis of the IRT distributions of the three groups showed a different pattern of results. The saline and 1.0 mg/kg DFP groups produced nearly identical IRT distributions, while the 2.6 mg/kg group produced an IRT distribution which was marked by significant increases in the interquartile range and median IRT. Since the 1.0 mg/kg dose of DFP produced a circadian disruption but did not affect the IRT distribution, it appears that the disruption of circadian activity by DFP which was reported by Raslear and Kaufman cannot be solely explained by simple changes in the motor response.
Animals↗