The influence of nitrogen in stemflow and precipitation on epiphytic bryophytes, Isothecium myosuroides Brid., Dicranum scoparium Hewd. and Thuidium tamariscinum (Hewd.) Schimp of Atlantic oakwoods.

The spatial relationship between the concentration and deposition of the major ions in precipitation and stemflow and their influence on the tissue nitrogen concentration of three epiphytic bryophytes on Quercus petraea (Matt) Liebl. and Q. robur L. was investigated at seven UK Atlantic oak woodland sites with a range of total N deposition of 55-250 mmol m(-2). The main driver of change in tissue N concentrations of three epiphytic bryophytes (Isothecium myosuroides Brid. (Eurhynchium myosuroides (Brid.) Schp.), Dicranum scoparium Hewd. and Thuidium tamariscinum (Hewd.) Schimp.) was total N deposition in stemflow, dominated by ammonium deposition. The three epiphytic species also showed strong relationships between tissue N concentration and total N deposition in rainfall but a poor correlation with total N ion concentration in rainfall. This study shows that epiphytic bryophytes utilise stemflow N and thus increase their risk from inputs of total N deposition compared to terricolous species at the same site.

Vegetation composition of roadside verges in Scotland: the effects of nitrogen deposition, disturbance and management.

Vehicular emissions of NO(x) and NH(3) result in elevated concentrations of nitrogen at roadside verges. To determine the extent that vehicular nitrogen emissions, disturbance and management affect the vegetation composition of road verges, a survey of 92 verges in Scotland was carried out with sites stratified by background nitrogen deposition and road type. NO(x) and NH(3) concentrations were monitored at 15 key sites for a year, and showed a decreasing gradient with increasing distance from the road. Ellenberg fertility indices of the vegetation communities also showed a general decrease with increasing distance from the road, but there was no straightforward correlation with NO(x) and NH(3) air concentrations between sites. Cover of bare ground, ruderal species and salt-tolerant species were highest at the verge edge. The proximity of the verge to traffic is important both in terms of NO(x) and NH(3) gradients, but also for deposited salt, grit and physical disturbance.

Face presentation at term.

A retrospective study was conducted of 50,300 consecutive deliveries between July of 1973 and January of 1978. There were 40 instances of face presentation with gestational age greater than 36 weeks and fetal weight greater than 2500 g for an incidence of 1 per 1250 deliveries. Cesarean section was performed in 50% of cases. Spontaneous vaginal delivery occurred with mentum anterior presentation 88% of the time, with mentum transverse presentation 45% of the time, and with mentum posterior presentation 25% of the time. Fetal heart rate (FHR) monitoring was available for review in 29 of the 38 (76%) live births. Internal techniques were used in 79% and external techniques in 21% of the cases. The FHR patterns were classified according to the predominant pattern seen in the first stage of labor. In 59% (17 of 29), variable decelerations were noted, and severe variable decelerations were present in 29% (8 of 29). Late decelerations were noted in 24% (7 of 29) of cases. Only 4 patients completed labor without variable or late decelerations. There were 38 live births and 2 stillbirths. Both of the stillborns were noted to have tight nuchal cords which were believed to be the cause of death. One death occurred intrapartum. Of the 38 live births, there were 14 (37%) with 1-minute Apgar scores of 6 or less and 5 (13%) with 5-minute Apgar scores less than 7. Four of the 5 low 5-minute Apgar scores occurred in babies with mentum posterior position. Of the 23 patients monitored by internal electrodes, no serious trauma was noted as a result of the electrode placement.