Computational fluid dynamics vs. inverse dynamics methods to determine passive drag in two breaststroke glide positions.

Computational fluid dynamics (CFD) plays an important role to quantify, understand and "observe" the water movements around the human body and its effects on drag (D). We aimed to investigate the flow effects around the swimmer and to compare the drag and drag coefficient (CD) values obtained from experiments (using cable velocimetry in a swimming pool) with those of CFD simulations for the two ventral gliding positions assumed during the breaststroke underwater cycle (with shoulders flexed and upper limbs extended above the head-GP1; with shoulders in neutral position and upper limbs extended along the trunk-GP2). Six well-trained breaststroke male swimmers (with reasonable homogeneity of body characteristics) participated in the experimental tests; afterwards a 3D swimmer model was created to fit within the limits of the sample body size profile. The standard k-ε turbulent model was used to simulate the fluid flow around the swimmer model. Velocity ranged from 1.30 to 1.70 m/s for GP1 and 1.10 to 1.50 m/s for GP2. Values found for GP1 and GP2 were lower for CFD than experimental ones. Nevertheless, both CFD and experimental drag/drag coefficient values displayed a tendency to jointly increase/decrease with velocity, except for GP2 CD where CFD and experimental values display opposite tendencies. Results suggest that CFD values obtained by single model approaches should be considered with caution due to small body shape and dimension differences to real swimmers. For better accuracy of CFD studies, realistic individual 3D models of swimmers are required, and specific kinematics respected.

The incidence of maternal fever during labor is less with intermittent than with continuous epidural analgesia: a randomized controlled trial.

BACKGROUND: This prospective, randomized study was performed to see if intermittent labor epidural analgesia was protective against maternal intrapartum fever, compared to continuous epidural infusion. METHODS: Ninety-two healthy, term, nulliparous women in spontaneous labor were assigned to either intermittent (ILEA) or continuous labor epidural analgesia (CLEA), 46 in each group. In both groups, epidural analgesia was established with fentanyl 100 microg, and 8 mL of either 0.125% bupivacaine with fentanyl 0.0002%, or 0.1% ropivacaine with fentanyl 0.0002%. Maintenance in the CLEA group was with the same bupivacaine/fentanyl or ropivacaine/fentanyl solutions at 10-15 mL/h. In the ILEA group, additional boluses of the same solution were given as needed. Maternal tympanic temperature was measured before epidural insertion, 4-hourly during labor and 4 h post partum. Fever was defined as a temperature of > or =38 degrees C. Newborn temperature was noted within 60 min of birth. RESULTS: The incidence of fever in ILEA was significantly lower at four hours (2/42, vs. 10/44 in CLEA, P=0.036). No significant differences were detected at other time periods. Mean maternal temperatures did not differ between groups at any time. There were no differences in neonatal temperature or neonatal sepsis evaluation rate (CLEA vs. ILEA 0/46 vs. 2/43, P=0.45). CONCLUSIONS: Intermittent epidural injections appear to protect against intrapartum fever in the first 4 hours of labor analgesia, compared to continuous infusion. This may be due to intermittent partial recovery of heat loss mechanisms between injections. Neonatal sepsis evaluation rates were similar in the two groups.

Off-flavors in milk.

This report is a review of off-flavors encountered in fluid milk. It includes sections on transmitted, microbial, lipolyzed, heated, light-activated, oxidized, and miscellaneous flavors. Finally, the flavor of ultrahigh temperature (UHT) milk is reviewed. Most of the literature cited for different off-flavors covers the period since a comprehensive review was done of milk flavors by Strobel et al. (1953). In addition to causative agents and volatile materials associated with off-flavors, methods for control of each of the off-flavors are presented. This report is designed to serve the dairy production and processing industry, students and faculty of food science curricula, dairy product evaluation students, regulatory people, and fieldmen.