Retention of native woody vegetation on farms in Australia: management considerations,planning guidelines and information gaps

Australia's forests and woodlands have been extensively cleared since European settlement. Cropping regions have the least retained native vegetation, with the greatest depletion of forests and woodlands being observed in Western Australia and South Australia. Salinisation, erosion and landslides have resulted from excessive clearing and inappropriate tree removal from particular units within the landscape. Major problems in cropping regions are the dramatic reduction in total woody cover and the fragmentation of retained vegetation into isolated remnant patches which tend to be very small (<10–15 ha). Those states with little remnant vegetation have legislation which restricts further clearing and the main emphasis is on managing remnant patches for conservation. For those states with a large proportion of woody vegetation uncleared, the main priority is to ensure that past mistakes are not repeated and that any vegetation clearance is based upon sound ecological principles.Throughout Australia, the condition of the remaining vegetation is of great concern and management guidelines for both conservation and production are being sought. Clearing may lead directly to soil erosion, but often the cause of erosion is inappropriate post-clearing management. Overgrazing is a major cause of vegetation and soil degradation, particularly in semi-arid regions.An understanding of the complex inter-relationship between woody vegetation, grazing and fire is necessary if 1) flora and fauna are to be conserved; 2) hydrological balance is to be maintained; and 3) rural industries are to remain viable. Planning at the catchment level is necessary to implement strategies to meet conservation and hydrological goals. Within that framework, individual property planning must include consideration of the area of native woody vegetation to be retained and its configuration. In many cases, the purpose of retention will influence the decisions of where and how native vegetation should be retained.     

Fullerene pipes

Single-wall fullerene nanotubes were converted from nearly endless, highly tangled ropes into short, open-ended pipes that behave as individual macromolecules. Raw nanotube material was purified in large batches, and the ropes were cut into 100- to 300-nanometer lengths. The resulting pieces formed a stable colloidal suspension in water with the help of surfactants. These suspensions permit a variety of manipulations, such as sorting by length, derivatization, and tethering to gold surfaces.     

Circular polarization in star- formation regions: implications for biomolecular homochirality

Strong infrared circular polarization resulting from dust scattering in reflection nebulae in the Orion OMC-1 star-formation region has been observed. Circular polarization at shorter wavelengths might have been important in inducing chiral asymmetry in interstellar organic molecules that could be subsequently delivered to the early Earth by comets, interplanetary dust particles, or meteors. This could account for the excess of L-amino acids found in the Murchison meteorite and could explain the origin of the homochirality of biological molecules.     

Changes in urinary and plasma oestrone sulphate concentrations after induction of foetal death in mares at 45 days of gestation

Foetal death was induced in 10 Standardbred mares at day 45 of gestation by injecting 20 to 45 ml of hypertonic (24% W/V) saline into the conceptus at surgery. Ten mares underwent sham treatment and acted as controls. Blood and urine samples were collected every other day between days 30 and 45 post ovulation and at 0, 3 and 6 h relative to the infusion of saline in the treated mares, or sham treatment in control mares. Blood and urine samples were then collected daily between days 46 and 55 post ovulation. Urine oestrone sulphate (E1S) concentrations, measured by radioimmunoassay, increased between day 34 and day 36 of gestation in treated and control groups. In mares in which foetal death was induced, urine E1S concentrations declined post-operatively and were significantly (p less than .05) lower than controls by day 50. In plasma, E1S concentrations showed a major increase between days 36 and 40 in both groups. This was followed by a rapid decline after treatment in saline-injected mares, so that by day 48 plasma E1S concentrations in treated mares were significantly (P less than .05) lower than the controls. The results show that urinary and plasma E1S concentrations rise rapidly during early pregnancy, and are associated with a viable foetus after day 45 of pregnancy.