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Ten-year-old 'Tai So' lychee (Litchi chinensis Sonn.) trees growing on a sandy loam soil in subtropical South Africa (latitude 25 degrees S) were watered weekly (well-watered treatment) or droughted from late July until January (drought treatment). After 16 weeks, at which time the trees obtained most of their water from below 150 cm, average soil water content at 0 to 150 cm depth was 14.5 +/- 0.1% in the well-watered treatment and reached a minimum of 7.6% in the drought treatment. At Week 7, minimum leaf water potential (Psi(L)) in the morning and early afternoon declined to -2.6 and -2.8 MPa, respectively, in droughted trees compared with -1.5 and -2.2 MPa, respectively, in well-watered trees. From Week 9, stomatal conductance and net CO(2) assimilation rate ranged from 70 to 300 mmol m(-2) s(-1) and 3 to 13 micro mol CO(2) m(-2) s(-1), respectively, in well-watered trees. The corresponding values for droughted trees were 50 to 180 mmol m(-2) s(-1) and 2 to 6 micro mol CO(2) m(-2) s(-1). Five weeks after rewatering the droughted trees, gas exchange had not recovered to the rate in well-watered trees, although tree water status recovered within a week of rewatering. In the well-watered trees, water use (E(t)) was 26 +/- 1 mm week(-1) with evaporation (E(p)) of 20 to 70 mm week(-1) indicating a crop factor (k(c) = E(t)/E(p)) of 0.4 to 1.2. Before anthesis, tree water status did not affect extension growth of floral panicles or leafy shoots. In contrast, no vegetative shoots were initiated after fruit set in the droughted trees when Psi(L) in the morning declined to -2.5 MPa. Water deficits reduced initial fruit set by 30% and final fruit set by 70% as a result of fruit splitting (41.2 +/- 4.0% versus 10.0 +/- 1.3%). Water deficits did not alter the sigmoidal pattern of fruit growth, but reduced yield from 51.4 +/- 5.5 kg tree(-1) in well-watered trees to 7.4 +/- 3.3 kg tree(-1) in droughted trees.

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Transpalatal trans-sphenoidal approaches to the sella turcica were described as early as 1900. Since the advent of effective trans-sphenoidal pituitary microsurgery in the 1960's, the sublabial transnasal approach became the most widely used. We reassessed the transoral transpalatal approach in 1978 and found the procedure to have distinct advantages over the transnasal operation. Between 1978 and 1992, 94 patients had transpalatal trans-sphenoidal explorations of the pituitary fossa at our institution. The detail of the operative technique, the results and the advantages are discussed.

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A Streptococcus species biochemically and serologically identical to the rainbow trout pathogenic Streptococcus species was isolated from the internal organs of the fish specific leech, Batracobdelloides tricarinata. These leeches were obtained from Roodeplaat Dam, near Pretoria, in which rainbow trout do not occur. This is the first isolation of this bacterium from an environmental source not related to rainbow trout and it is proposed that this leech is a possible reservoir of the rainbow trout pathogenic Streptococcus sp. in South Africa.

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The sympathetic response to laryngoscopy and intubation was studied in 39 patients who were to undergo surgical clipping of a cerebral aneurysm. Intravascular radial artery pressure and ECG monitoring for ST-segment changes or dysrhythmias were used. Ward blood pressures were controlled on bed rest and labetalol. Induction of anaesthesia was with pentothal 4 mg/kg and suxamethonium 1 mg/kg intravenously. This was followed by one of the following intravenous agents by random choice: alfentanil 30 micrograms/kg, fentanyl 5 micrograms/kg, lignocaine 2 mg/kg, and lignocaine 10% spray 2 mg/kg to the larynx. ECG changes at laryngoscopy and intubation were minimal. Intubation produced an immediate increase in blood pressure and pulse rate, maximal at 30-60 seconds, falling rapidly towards normal within 2-3 minutes. Alfentanil was very effective in obtunding this response with stable cardiovascular parameters; fentanyl produced a more variable response; and intravenous lignocaine was less satisfactory. Lignocaine spray was ineffective.

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The effects of parasitism by leeches Theromyzon cooperi and Placobdella garoui on the redbilled teal Anas erythrorhyncha were investigated. Leeches with initial body mass ranging from 5.2 to 28.4 mg were allowed to parasitize redbilled teal clamped in Perspex containers. Theromyzon cooperi increased its body mass after parasitism with a mean of 10.5-fold compared to 6.9-fold for P. garoui. Changes were also observed in values of various haematological and biochemical variables of the redbilled teal monitored during this investigation.

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