Home-range use by the brush-tailed phascogale (phascogale tapoatafa) (marsupialia) in High-quality, spatially limited habitat

Nine phascogales (7 females, 2 males) were radio-tracked between March and July 1999 to investigate the spatial organisation of this species in spatially limited habitat near Euroa, Victoria. In this area, approximately 3.6% of the original woodland vegetation remains after 150 years of agricultural clearing. Most wooded habitat is confined to narrow linear strips along roads and streams. However, these remnants are on fertile soils and, because they have not experienced intensive harvesting, the density of large old trees is over 10 times that found in nearby State Forests and Parks. Female phascogales were monitored for 13–38 days over periods of 5–15 weeks. The size of home ranges of females was 2.3–8.0 ha, and averaged 5.0 ha. This value is one-eighth the mean home-range size previously recorded for the species in contiguous forest in Victoria. All individuals used multiple nest trees, with nests generally located in trees >80 cm diameter at breast height. Although fragmented and spatially limited, the stands of large old trees on productive soils near Euroa provide a network of well connected, high-quality habitat for phascogales. The relatively dense population of phascogales in these remnants suggests that prior to agricultural clearing and timber harvesting, phascogales may have been much more common in Victoria than at present.

Nest-tree selection by the threatened brush-tailed phascogale (phascogale tapoatafa) (marsupialia: dasyuridae) in a highly fragmented agricultural landscape

The conservation of roosting and nesting resources is of critical concern for many hollow-dependent species around the world. We investigated the nest-tree requirements of the threatened brush-tailed phascogale (Phascogale tapoatafa) in a highly cleared agricultural landscape in south-eastern Australia. We documented the physical characteristics of selected nest trees and describe the spatial and temporal patterns of nest-tree use as revealed by radio-tracking. Nine phascogales (seven females, two males) were radio-tracked between March and July 1999 in an area where most woodland habitat is confined to linear strips along roads and streams or small patches and scattered trees in cleared farmland. Female phascogales were monitored for 13–35 days over periods of 5–15 weeks and two males were monitored for 2 and 9 days respectively. A total of 185 nest-tree fixes was collected and all nests occupied by phascogales were in standing trees. Eighty-three nest trees were identified, ranging in diameter at breast height (dbh) from 25 to 171 cm, with a mean dbh for the trees used by each individual phascogale of >80 cm. Phascogales did not discriminate between canopy tree species in selecting nest trees, but showed highly significant selection for trees in the largest size class. All individuals used multiple nest trees, with the seven females occupying an average of 11.4 nest trees from a mean of 25 diurnal locations. The number of nest trees continued to increase throughout the study, suggesting that more would be identified during a longer or more intensive study. Occupied nest trees were located throughout each individual’s home range, highlighting the importance of a continuous spatial distribution of suitable nest trees across the landscape. Nest trees were also located in adjacent farmland up to 225 m from roadside vegetation, demonstrating the value that scattered clumps and even single trees in farmland can have for wildlife conservation.

The effect of Nb, Mo, and A1 additions on the transformation behaviour and mechanical properties of thermomechanically processed C-Si-Mn trip steel

The effect of additions of Nb, A1 and Mo to Fe-C-Mn-Si TRIP steels on the final microstructure and mechanical properties after simulated thermomechanical processing (TMP) has been studied. Laboratory simulations of continuous cooling during TMP were performed using a quench deformation dilatometer, while laboratory simulations of discontinuous cooling during TMP were performed using a hot rolling mill. From this a comprehensive understanding of the structural and kinetic aspects of the bainite transformation in these types of TRIP steels has been developed. All samples were characterised using optical microscopy and XRD. The relationships between the morphology of bainitic structure, volume fraction, stability of RA and mechanical properties were investigated.

The skeletal benefits of calcium- and vitamin D3-fortified milk are sustained in older men after withdrawal of supplementation: an 18 mo follow-up study

Background: In a previous 2-y randomized controlled trial, we showed that calcium- and vitamin D₃–fortified milk stopped or slowed bone loss at several clinically relevant skeletal sites in older men.

Objective: The present study aimed to determine whether the skeletal benefits of the fortified milk were sustained after withdrawal of the supplementation.

Design: One hundred nine men >50 y old who had completed a 2-y fortified milk trial were followed for an additional 18 mo, during which no fortified milk was provided. Bone mineral density (BMD) of the total hip, femoral neck, lumbar spine, and forearm was measured by using dual-energy X-ray absorptiometry.

Results: Comparison of the mean changes from baseline between the groups (adjusted for baseline age, BMD, total calcium intake, and change in weight) showed that the net beneficial effects of fortified milk on femoral neck and ultradistal radius BMD at the end of the intervention (1.8% and 1.5%, respectively; P < 0.01 for both) were sustained at 18-mo follow-up (P < 0.05 for both). The nonsignificant between-group differences at the total hip (0.8%; P = 0.17) also persisted at follow-up (0.7%; P = 0.10), but there were no lasting benefits at the lumbar spine. The average total dietary calcium intake in the milk supplementation group at follow-up approximated recommended amounts for Australian men >50 y old (1000 mg/d) but did not differ significantly from that in the control subjects (1021 versus 890 mg/d).

Conclusion: Supplementation with calcium- and vitamin D₃–fortified milk for 2 y may provide some sustained benefits for BMD in older men after withdrawal of supplementation.

Processing and mechanical properties of porous Ti-Mo alloy for biomedical applications

Titanium and some of its alloys are well accepted as load-bearing implant materials due to their excellent mechanical properties, superior corrosion resistance, and outstanding biocompatibility. However, solid implant materials may suffer from the problems of adverse tissue reaction, biomechanical mismatch and lack of new bone tissue ingrowth ability. In the present study, porous titanium-molybdenum (Ti-Mo) alloy was fabricated by the space-holding sintering method. The pore size, pore shape and porosity can be controlled through choosing appropriate space-holding particle materials. Electron scanning microscopy (SEM) was used for the characterisation of the porous Ti-Mo alloy. The mechanical properties of the porous Ti-Mo alloy samples were investigated by compressive tests. Results indicated that the porous Ti-Mo alloy provides promising potential for new implant materials with new bone tissue ingrowth ability and mechanical properties mimicking those of natural bone.

Development of mound-building in Australian brush-turkeys (Alectura lathami) : the role of learning, testosterone and body mass

Australian brush-turkeys (Alectura lathami) hatch in incubation mounds of organic material and have no parental role models to learn from. When raised in outdoor aviaries, without adults, four of six males built incubation mounds at an early age of 4.5–9 months. The two males without mounds were the only ones without detectable levels of testosterone (T) at 4.5 months, whereas body mass did not explain the presence or absence of mound building. At the age of 11 months, all males had detectable T, including those without mounds. This study also investigated the development of social dominance in males kept in mixed-sex groups for 4.5 months. At this latter age, higher-ranked males tended to have higher T levels (P = 0.076), whereas dominance ranks at 4.5 months were not correlated with body mass or size, either at this age or at hatching. Overall, these results suggest that mound building develops without learning, and there is a relationship between T levels and dominance status as well as the absence or presence of mound building. These findings contribute to discussions on the role of learning in behavioural development and the role of T and body mass in avian life history.

Nutrients in Pirron Yallock Creek, southwestern Victoria : paleolimnological and management considerations

The concentrations of various forms of nitrogen and phosphorus in the main stream and selected tributaries of Pirron Yallock Creek, southwestern Victoria were examined over a two-year period. Exceedingly high levels of both nutrients were found within a particular tributary, while generally high nutrient levels were observed throughout the catchment. The speciation results indicated that dairy effluent was the primary source of nutrients to Pirron Yallock Creek. A palaeolimnological study was undertaken to determine the impact of European settlement upon waterway nutrient concentrations within the region. The palaeolimnological study focused primarily on the diatom flora preserved within the sediments of nearby Lakes Corangamite and Bullen Merri. Lack of preservation of diatoms within the sediments of Lake Corangamite resulted in no water quality inferences for this lake. The preserved diatoms within Lake Bullen Merri suggested an increase in trophic status of this lake during the last 500 years. While a change in the diatom flora of Lake Bullen Merri was evident, it was not possible to differentiate the impact of European settlement upon nutrient status of this waterway from long-term trophic status change. In light of the particularly high nutrient concentrations observed in Pirron Yallock Creek, improved nutrient management strategies are proposed for the catchment. These strategies, which consider current nutrient management activities, are predominantly focussed on the dairy industry, which occupies the majority of the catchment.