A COMPARISON OF REAL-TIME ULTRASOUND, PALPATION AND RADIOGRAPHY IN PREGNANCY DETECTION AND LITTER SIZE DETERMINATION IN THE BITCH

Fifty-five bitches were examined once, at different intervals for pregnancy. Manual Papation, B-mode real-time ultrasoungraphy, and radiography were used to confirm pregnancy and to count the number of fetuses present. Predicted numbers were compared to whelping data obtained from owners. Radiography was confined to the last trimester of pregnancy and had an overall accuracy of 100% in pregnancy detection and 93% in correct litter size determination. A proor qualtiy radiograph contributed to the one incorrect count estimate. Ultrasound and palpation were used in all three trimester phases starting 3 weeks post coitus. For pregnancy detection ultrasound was 94% accurate (no false positives) and palpation was 88% accurate (one false positive). For fetal counting, ultrasound was 36% accurate and palpation was 12% accurate. Recommendations for the use of ultrasound and radiography in pregnancy evaluation are reviewed.     

Bilateral Calcaneal Epiphysiolysis in a Dog

Ununited epiphyses were seen in the calcanei of a 13-month-old Rottweiler with abnormal rear limb conformation. Histologic examination of the tissues showed a nonunion with neoarthrosis formation. Surgical management included use of tension band and lag screw techniques to achieve epiphysiodesis that was radiographically evident 12 weeks postsurgery. There was no sign of lameness when examined 8 months after surgery. Similarities exist between this case and that of osteochondrosis in other domestic species, and with Osgood-Schlatters disease in humans. Osteochondrosis and/or abnormal angulation of the hocks were suspected as the underlying cause of the epiphyseal separations.     

Germination, persistence, and emergence of flaxleaf fleabane (Conyza bonariensis [L.] Cronquist)

Flaxleaf fleabane ( Conyza bonariensis [L.] Cronquist) is a difficult-to-control weed in dryland minimum tillage farming systems in the northern grains region of Australia. Experiments under field and controlled environments were conducted to study the seed germination, emergence, and persistence of C. bonariensis . The base, optimum, and maximum temperatures for seedling germination were estimated at 4.2, 20, and 35°C, respectively, with light stimulating germination. The soil types and burial depths had significant effects on seed persistence and emergence. The persistence pattern showed an initial rapid drop, followed by a slow but steady decline over time. After 3 years of burial, there were ≈ 7.5%, 9.7%, and 1.3% viable seeds at 10, 5, and 0–2 cm soil depths, respectively. Conyza bonariensis predominantly emerged from the soil surface or from the burial depth of 0.5 cm. Very few seeds emerged from a depth of 1 cm and none emerged from ≥ 2 cm. The emergence was greater in lighter soils. On-farm monitoring of the field emergence over time in a light sandy loam soil showed that 99% emergence occurred in late autumn, early and late winter, and a small fraction of 1% emerged in mid-spring. The predominant emergence from the soil surface suggests that the fleabane problem is a result of weed species shift toward the minimum tillage systems that provide moist conditions for better emergence compared to conventional tillage systems. The seed longevity of at least 3 years in the soil and the prolonged emergence patterns between autumn and spring have posed great difficulties for the long-term management of C. bonariensis .     

Earthquakes on dipping faults: the effects of broken symmetry

Dynamic simulations of earthquakes on dipping faults show asymmetric near-source ground motion caused by the asymmetric geometry of such faults. The ground motion from a thrust or reverse fault is larger than that of a normal fault by a factor of 2 or more, given identical initial stress magnitudes. The motion of the hanging wall is larger than that of the footwall in both thrust (reverse) and normal earthquakes. The asymmetry between normal and thrust (reverse) faults results from time-dependent normal stress caused by the interaction of the earthquake-generated stress field with Earth's free surface. The asymmetry between hanging wall and footwall results from the asymmetric mass and geometry on the two sides of the fault.     

SUSTAINABLE NITROGEN MANAGEMENT IN AUSTRALIAN AGROECOSYSTEMS: CHALLENGES AND OPPORTUNITIES

● There is huge potential for improvement of nitrogen management in Australia. ● N management should incorporate environmental, social and economic sustainability. ● Agronomic, ecological and socioeconomic approaches and efforts are needed. Nitrogen is an essential nutrient that supports life, but excess N in the human-environment system causes multiple adverse effects from the local to the global scale. Sustainable N management in agroecosystems, therefore, has become more and more critical to address the increasing concern over food security, environmental quality and climate change. Australia is facing a serious challenge for sustainable N management due to its emission-intensive lifestyle (high level of animal-source foods and fossil fuels consumption) and its diversity of agricultural production systems, from extensive rainfed grain systems with mining of soil N to intensive crop and animal production systems with excessive use of N. This paper reviews the major challenges and future opportunities for making Australian agrifood systems more sustainable, less polluting and more profitable.     

Definition and use of the term 'pedoderm'

A new system for soil studies has been proposed by Butler based on his earlier Kcycle concept. In doing so, he has re-defined ‘pedoderm’, the soil stratigraphic term originally defined in the Australian Soil-Stratigraphic Proposal (ASSP). Some aspects of soil stratigraphy are discussed and the ASSP outlined. From these considerations we conclude that the re-definition of pedoderm is inappropriate. We strongly recommend the original definition and usage of the term pedoderm. It was widely discussed among earth scientists and was developed by the careful testing of a number of alternative proposals. The term with its original definition has recently been adopted by the INQUA/Paleopedology Working Group on Soil Stratigraphy.     

Micromorphology and sub-microscopy of allophane and imogolite in a podzol Bs horizon: evidence for translocation and origin

In thin sections of a cemented Bs horizon, allophane is present as isotropic, or weakly anisotropic, transparent, yellow, commonly fluorescent gel deposits, which line or fill voids, cement sand and silt, and form pseudomorphs of root structures. Atomic ratios of Si: Al range from 1: 2.2 to 1: 3.7 in pale deposits, but drop to 1: 8.8 in regions of organic staining. Fe: Al atomic ratios in transparent deposits range from near zero to 0.4. The local uniformity of the gels indicates that the allophane, with associated iron oxides, is deposited from solution, and is not formed in situ from a precipitated organic complex, or by weathering of minerals in situ. Mineralogical evidence indicates that the origin of the allophane is related to intense acidic weathering of plagioclase and biotites in the Eg and Bhg horizons. A fibrous morphology indicative of imogolite is seen under the scanning electron microscope only in critical point dried specimens. It is proposed that the cracked coatings characteristic of cemented Bs horizons can be interpreted as allophanic deposits, associated with varying amounts of clay and iron oxide, and impregnated with varying amounts of fulvic acids. Such deposits cannot be taken as evidence for the migration of Al and Fe as organic complexes.     

THE POTASSIUM STATUS OF SIX LOESSIAL SOILS OF CANTERBURY, NEW ZEALAND, IN RELATION TO RAINFALL AND RATE OF LOESS ACCUMULATION

A selection of greywacke-derived loessial soils in Canterbury, New Zealand, was examined to test the hypothesis that soil K status is a function of soil-forming factors. Soils were selected such that factors besides loess accumulation and rainfall were relatively constant and the effects of each variable could be isolated. Soil K status was evaluated by plant, chemical, and X-ray diffraction techniques. With increasing rainfall and decreasing rate of loess accumulation soil K status decreased; there was a concurrent decrease in illite and increase in interstratified mineral content of the clay fraction.