Infection of cattle in Queensland with bluetongue viruses: 1. prevalence of antibodies

SUMMARY A survey of nearly 20 000 cattle in Queensland was conducted to describe the prevalence and distribution of infection by serotypes of bluetongue virus. The overall prevalence of serum antibodies to one or more bluetongue viruses was 8.7% (95% confidence interval 8.3 to 9.1). Sera from cattle contained neutralising activity against 2 serotypes, 1 and 21. No evidence was found of infection with other serotypes previously isolated in Australia. The overall prevalence of serotype 1 antibodies was 7.7% (95% CI 7.3 to 8.0) and the prevalence of serotype 21 antibodies was 3.3% (95% CI 3.1 to 3.6). The prevalence of serotype 1 antibodies was significantly (P < 0.05) higher than that of serotype 21 in every region of the State, except in the central highlands and south-west Queensland. Overall, 3 significantly (P < 0.05) different zones of prevalence were found: high prevalence (> 20%) in far north Queensland, moderate (5 to 20%) in north-west, northern and southern coastal Queensland, and low (< 5%) in the central highlands, Darling Downs and south-west Queensland.     

Characterization of Polymyxa species by restriction analysis of PCR-amplified ribosomal DNA

A molecular method is described to aid identification of the obligate parasite Polymyxa and discriminate between species ( P. betae and P. graminis ) and isolates. DNA was extracted from zoospores, resting spores and roots infected with P. betae and P. graminis and compared with that from negative control plants that were not inoculated with Polymyxa but were grown at the same time under the same conditions. The ribosomal internal transcribed spacers and 5.8S rDNAs were amplified by the polymerase chain reaction and digested with restriction enzymes to detect molecular differences between the species and isolates. There were differences between P. betae and P. graminis and two subgroups within P. graminis but so far this has not been correlated with any other biological property.     

Optimising harvest strategies in a multi‐species bivalve fishery

Abstract Optimising harvests from fishery resources requires appropriate data. In this study, fishery‐independent survey and size‐at‐first maturity (L₅₀) data were used to assess the suitability of current minimum legal sizes (MLS) and total allowable commercial catches (TACC) in the South Australian, mixed‐species, mud‐cockle (Katelysia spp.) fishery. Estimates of L₅₀ suggested the MLS was conservative in one fishing zone (Coffin Bay), but appropriate elsewhere. Harvestable‐biomass estimates (HB) demonstrated that TACCs were excessive in the Port River (41% of HB), suitable in Coffin Bay (10% of HB) and precautionary in the West Coast (1.5% of HB) fishing zones. Consequently, the MLS was decreased by 5 mm shell length in Coffin Bay and the TACCs for the Port River (reduced by 80%) and West Coast (increased by 40%) amended. This study demonstrated that harvest strategies in mixed‐species fisheries can be optimised by explicitly considering data on species composition, abundance and population biology.     

River restoration: report of a major EU Life demonstration project

1. In 1993 the EU Life Programme granted funds to establish a demonstration project on river and catchment restoration. The aim is to improve understanding of ecosystem diversity, the impact on biodiversity of human activities, and the restoration of natural functions and biodiversity. The total cost of the project will be approximately £5 m up to the beginning of 1997. 2. The demonstration project covers three different types of rivers and geology in the UK and Denmark. The three damaged rivers and their floodplains have been restored on stretches of several kilometres. 3. A comprehensive monitoring programme has been set up to examine the physical, chemical and biological effects of restoration for integrated catchment management, nature conservation, water quality, river hydrology, flood prevention and amenity. 4. The project will also produce reports, videos, a river restoration handbook and other material on the development, implementation and results of the project. An EU network of contacts with organizations, river managers and others with interests in river restoration will be established.     

ENVIRONMENTAL ATTITUDES AND CONSUMER PREFERENCE FOR ENVIRONMENTALLY-FRIENDLY BEVERAGE PACKAGING: THE ROLE OF INFORMATION PROVISION AND IDENTITY LABELING IN INFLUENCING CONSUMER BEHAVIOR

This study examined whether urban Chinese consumers with stronger environmental values have higher valuations for plastic beverage bottles that are made of post-consumer recycled material(rPET) or that come in large sizes that use plastic more efficiently. It also assesses the effectiveness of environmental information provision and green identity labeling in increasing consumer willingness to pay for environmentally-friendly packaging. The results suggest that urban Chinese consumers are willin...     

Effects of age on the electroencephalographic response to castration in lambs anaesthetised using halothane in oxygen

AIM: To use the electroencephalogram (EEG) to ascertain whether the response of the cerebral cortex to the noxious stimulus of castration varied with age in lambs.

METHODS: Two groups of East Friesian lambs were selected according to age; the mean age of the younger group (n=21) was 12 (SD 2) days and the older group (n=20) was 29 (SD 1) days. Anaesthesia was induced via mask using 4% halothane in oxygen, and maintained using 1.5% halothane in oxygen at a flow rate of 4 L/min. Once a stable plane of anaesthesia had been achieved, data collection of EEG and electrocardiographic (ECG) readings commenced, and the lambs were castrated 15 min later, using rubber rings. Median and 95% spectral edge frequencies (F95) and total EEG power (ptot) were derived from data from the EEG.

RESULTS: Following castration, there was an increase in the median frequency (F50) in the younger lambs (p=0.002), and an increase in ptot in both groups (p=0.05), which was of greater magnitude in the older lambs. There were no significant changes in the F95. Both younger and older lambs exhibited a transient bradycardia (p=0.001 and p=0.01, respectively).

CONCLUSIONS: These differences in the cortical response between the two groups suggest that 2-week-old lambs undergo a qualitatively different perception of the noxious stimulus of castration compared to 4-week-old lambs.     

Pelagic ecology of a northern boundary current system: effects of upwelling on the production and distribution of sardine (Sardinops sagax), anchovy (Engraulis australis) and southern bluefin tuna (Thunnus maccoyii) in the Great Australian Bight

Shelf waters of southern Australia support the world's only northern boundary current ecosystem. Although there are some indications of intense nitrate enrichment in the eastern Great Australian Bight (GAB) arising from upwelling of the Flinders Current, the biological consequences of these processes are poorly understood. We show that productivity in the eastern GAB is low during winter, but that coastal upwelling at several locations during the austral summer–autumn results in localized increases in surface chlorophyll a concentrations and downstream enhancement of zooplankton biomass. Sardine (Sardinops sagax) and anchovy (Engraulis australis) eggs and larvae are abundant and widely distributed in shelf waters of the eastern and central GAB during summer–autumn, with high densities of sardine eggs and larvae occurring in areas with high zooplankton biomass. Egg densities and distributions support previous evidence suggesting that the spawning biomass of sardine in the waters off South Australia is an order of magnitude higher than elsewhere in southern Australia. Sardine comprised >50% of the identified prey species of juvenile southern bluefin tuna (SBT, Thunnus maccoyii) collected during this study. Other studies have shown that the lipid content of sardine from the GAB is relatively high during summer and autumn. We suggest that juvenile SBT migrate into the eastern and central GAB during each summer–autumn to access the high densities of lipid‐rich sardines that are available in the region during the upwelling period. Levels of primary, secondary and fish production in the eastern GAB during summer–autumn are higher than those recorded in other parts of Australia, and within the lower portion of ranges observed during upwelling events in the productive eastern boundary current systems off California, Peru and southern Africa.     

Photofragment helicity caused by matter-wave interference from multiple dissociative states

Isolated diatomic molecules of iodine monochloride (ICl) were photodissociated by a beam of linearly polarized light, and the resulting ground-state Cl atom photofragments were detected by a method that is sensitive to the handedness (helicity) of the electronic angular momentum. It was found that this helicity oscillates between "topspin" and "backspin" as a function of the wavelength of the dissociating light. The helicity originates solely from the (de Broglie) matter-wave interference of multiple dissociating pathways of the electronic excited states of ICl. These measurements can be related to the identity and to the detailed shapes of the dissociating pathways, thus demonstrating that it is possible to probe repulsive states by spectroscopic means.     

Energy Expenditure in 104 Postoperative and Traumatically Injured Dogs with Indirect Calorimetry

Apparent restihg energy expenditure (AREE) and respiratory quotient (RQ) were determined by open flow indirect calorimetry in a group of 104 apparently resting, critically ill, postoperative and severely traumatized dogs. The evaluations were conducted in a calm, temperature-controlled environment after at least a 12-hour fast. Subjects were allowed to acclimilate to the monitoring equipment prior to beginning the study. The clinical patients were compared to a group of 20 clinically normal, apparently resting, client owned dogs (NC). The data was also compared to published normals (NP) for energy expenditure of apparently resting dogs. Measurements were indexed to actual body weight in kilograms (BW) as well as to metabolic body size(BW^0.75). Measurements of VO₂ (VO₂/kg and VO₂/kg^0.75) and VCO₂ (VCO₂/kg and VCO₂/kg^0.75) were used to calculate the RQ and the AREE. Critically ill, postperative and severely lower RQ values AREE/kg or AREE/kg^0.75 (p=0.39). The PO&T dogs did exhibit significantly lower RQ values (p<0.0001) than either the (NC) or (NP) groups. Measured AREE of the PO&T dogs was significantly less than a calcualted value using the illness/injury/infection energy requirement (IER), (p<0.0001). Energy expenditure in typical trauma and postoperative patients may commonly be overstimated by the IER method. Conclusion: The AREE of critically ill, postoperative and severly trumatized dogs was not higher than healthy dogs as has been previously suggested in the literature.