Water-use efficiency of a mallee eucalypt growing naturally and in short-rotation coppice cultivation

This study compared mature Eucalyptus kochii subsp. plenissima trees in inner regions or edges of natural bushland to young trees belt-planted through cleared agricultural land as uncut saplings or regenerating coppice over 2.7 years at Kalannie, Western Australia (320 mm annual rainfall). We assessed the ability of the species to alter its gas exchange characteristics, leaf physical attributes, and water-use efficiency of foliar carbon assimilation (WUE _i) or of total dry matter production (WUE _DM). Stomatal conductance (g _s) varied five-fold between treatment means, with coppices exhibiting greatest values and mature bush least. Photosynthetic rates followed this trend. Leaf photosynthetic capacity estimated by chlorophyll content varied 1.3-fold parallel with variations in leaf thickness, with coppices rating lowest and mature edge trees most highly. WUE _i varied 1.5-fold between treatments and was greatest in mature inner-bush and edge trees. Leaf photosynthetic capacity and g _s were both correlated with WUE _i. Carbon isotope composition (δ¹³C values) of new shoot dry matter produced early in a seasonal flush were similar to those of root starch but when averaged over the whole season correlated well with WUE _i and gas exchange characteristics of trees of each treatment. Coppices showed poorest WUE _i and most negative shoot tip δ¹³C but their WUE _DM was high. This discrepancy was suggested to relate to carbon allocation strategies in coppices favouring fast growth of replacement shoots but not of roots. Physiology of coppice growth of E. kochii is usefully geared towards both rapid and water-use efficient production of woody biomass in water limited environments.     

Effects of temperature, pH, and salt concentration on beta-lactoglobulin deposition kinetics studied by optical waveguide lightmode spectroscopy

Deposition kinetics of beta-lactoglobulin at a solid-liquid interface was studied with optical waveguide lightmode spectroscopy (OWLS) over a range of temperatures between 61 and 83 degrees C. A new temperature-controlled cell for OWLS measurements allows fast, on-line monitoring of the deposit formation at elevated temperatures. Primary protein layers were deposited at 25 degrees C in order to precondition and stabilize the waveguide surface. Sustained deposition lasting from a few minutes (around 80 degrees C) to hours (below 70 degrees C) resulted in multilayer deposits up to several tens of nanometers thick. The measured deposition rates were strongly influenced by temperature, pH, and NaCl concentration. Deposition rates decreased with increasing pH from 5.5. to 7.4, in a trend similar to that for noncovalent aggregation of beta-lactoglobulin in solution. Activation energies for deposition rates decreased with increasing pH, from 340 kJ/mol at pH 5.5 to 230 kJ/mol at pH 7.4 and were similar to the activation energies for denaturation of beta-lactoglobulin in solution.     

Charges for comprehensive obstetric care at teaching and nonteaching hospitals. A comparison.

We compared total charges for obstetric care at a major teaching hospital and faculty group practice with those at 3 nonteaching centers in western Washington. The patients were all enrollees of an employee-based health maintenance organization. Charges were used as a proxy for costs and included all outpatient, inpatient, and physician charges. In the teaching system, patients were cared for by faculty and house staff; in the nonteaching settings, they received care from private physicians. No significant differences in total charges were found between the teaching and the nonteaching settings for all deliveries ($4,652 [N = 90] versus $4,530 [N = 335], P greater than .5). In the teaching setting, vaginal deliveries were slightly more expensive ($4,178 [n = 75] versus $3,768 [n = 250], P = .15), as were cesarean deliveries ($7,024 [n = 15] versus $6,771 [n = 85], P greater than .5). The rate of cesarean deliveries was lower in the teaching setting (17% versus 25%, P = .10), partially accounting for the similarity in total charges. The length of stay was similar in the teaching hospital (3.29 versus 3.14 days, P greater than .5). We conclude that the academic medical center as a total system of care can provide obstetric care as cost-effectively as nonteaching systems under the constraints of prepaid care.