Effects of artificial foods on the blood chemistry of the Australian magpie

Bird feeding on residential property is a popular activity throughout Western countries. Advocates insist the practice is beneficial, while opponents maintain that it can result in a wide range of negative outcomes including malnutrition. The biological effects of 'backyard feeding' were studied in Australian magpies Gymnorhina tibicen during the non-breeding season in 1999 in the Greater Brisbane and the Lockyer Valley regions, south-east Queensland, Australia. Six magpie populations were selected and 70 birds were individually tagged for identification. The birds were provided with processed foods, 20-40 g per bird daily. To monitor the effects of the food, blood chemistry and body mass (BM) were used as indices. Significant effects were observed in BM and plasma cholesterol (PC), showing strong sensitivity to food provisioning. Significant effects on PC and uric acid were found only when birds were fed dog sausage. Results suggest that blood PC levels in magpies are readily influenced by, probably, the lipids present in food, and that the type of food can affect blood PC levels. These effects may occur widely among fed magpies if the influence that we demonstrated at plasma level can be generalized. Following the free-ranging study, six magpies were captured and subjected to a 6-day captive experiment to determine whether the selected foods had the potential to alter the birds' blood chemistry. It was found that all of the foods, when provided ad libitum, influence at least two of the three blood parameters (PC and non-esterified fatty acids). Due to its popularity, wildlife feeding will continue. To make wildlife-feeding activities truly sustainable, there is a need for further studies. This study clearly demonstrated that the physiology of wild magpies can be affected by 'backyard feeding'.

Effects of Lyngbya majuscula (Cyanophycea) blooms on sediment nutrients and meiofaunal assemblages in seagrass beds in Moreton Bay, Australia

Blooms of Lyngbya majuscula have been increasingly recorded in the waters of Moreton Bay, on the south-east coast of Queensland, Australia. The influences of these blooms on sediment infauna and the implications for sediment biogeochemical processes was studied. Sediment samples were taken from Moreton Bay banks during and after the bloom season. The deposition of L. majuscula seems to be responsible for the higher total Kjedahl nitrogen (TKN) concentrations measured during the bloom period. Total organic carbon (TOC) concentrations did not change. Lyngbya majuscula blooms had a marked influence on the meiobenthos. Nematodes, copepods and polychaetes were the most abundant groups of meiofauna, and the bloom produced a decrease in the abundance and a change in the sediment depth distribution of these organisms. The distribution of nematodes, copepods and polychaetes in sediment became shallower. Further, the bloom did not affect the abundance and distribution of polychaetes as strongly as it did copepods and nematodes. The changes observed in the distribution of meiofauna in the sediment during the bloom period indicate that L. majuscula produces oxygen depletion in sediments, and that different fauna seem to be affected to different degrees.

Increase in skin cancer screening during a community-based randomized intervention trial

Survival from cutaneous melanoma is mainly dependent on the thickness of the lesion at diagnosis. Skin screening may increase detection of thin lesions and hence improve survival. Within a community-based randomized controlled trial of a population screening program for melanoma in Queensland, Australia, 9 communities were randomly assigned to the 3-year intervention and 9 communities to the control group. Skin screening prevalence was monitored by cross-sectional surveys at baseline, 1, 2 and 3 years into the intervention and 2 years later. At baseline, prevalence of whole-body clinical skin examination was similar in intervention and control communities. In intervention communities, the prevalence of whole-body skin examinations increased to 29.2%, an absolute difference of 18% from baseline, with a peak of 34.8% 2 years after baseline, and began to decline again at the end of the intervention period. The largest increases were seen in men and women ≥50 years. Uptake of screening did not differ according to melanoma risk factors; however, the decline in screening was less in participants who reported a number of melanoma risk factors. The prevalence of skin self-examination remained stable during the intervention program. No changes were observed in the control communities. These results indicate that the intervention program significantly increased the prevalence of whole-body clinical skin examinations in intervention communities. Once the intervention program ceased, and particularly after skin clinics ceased, levels of skin screening began to decline. The provision of specialized skin screening clinics may be needed to achieve sufficient screening rates should population based screening for skin cancer be considered. © 2005 Wiley-Liss, Inc.

Laboratory evaluation of the effect of alternative prey and vegetation on predation of Culex annulirostris immatures by Australian native fish species

The impact of alternative prey and simulated vegetation on Culex annulirostris Skuse predation efficacy by Australian smelt, Retropinna semoni (Retropinnidae); crimson-spotted rainbowfish, Melanotaenia duboulayi (Melanotaeniidae); empire gudgeon, Hypseleotris compressa (Eleotridae); estuary perchlet, Ambassis marianus (Ambassidae); firetail gudgeon, Hypseleotris galii (Eleotridae); fly-specked hardyhead, Craterocephalus stercusmuscarum (Atherinidae); and Pacific blue-eye, Pseudomugil signifer (Atherinidae), was evaluated in Queensland, Australia. The presence of chironomid midge larvae and tusked frog, Adelotus brevis (Leptodactylidae), tadpoles did not have a significant negative impact on the predation rates of Cx. annulirostris by these 7 fish species. Hypseleotris galii, M. duboulayi, and R. semoni demonstrated strong preference for larvae of Cx. annulirostris over both alternative prey species. In the presence of alternative prey species, the mean predation rate of M. duboulayi on larvae of Cx. annulirostris remained greater than that of other fish species tested. When evaluated at varying densities of simulated vegetation, predation rates of all fish species were similar to those reported in open conditions.

The consumption of alcohol by Australian adolescents: A comparison of revenue and expenditure

Aims: To estimate (i) Australian government taxation revenue collected from the consumption of alcohol by adolescents and (ii) the amount spent by the government on interventions aimed at educating adolescents about the potential dangers of alcohol use. Design: Secondary data analysis. Setting: Australia. Findings: Australian adolescents (aged between 12 and 17 years, inclusive) spent approximately $217 million on alcoholic beverages in 2002, netting the Australian government approximately $112 million in tax revenue. This resulted in an average of $195 earned in tax per adolescent drinker. It is estimated that the Government spent approximately $17 million on adolescent drinking interventions in 2002, equating to an expenditure of about $10.51 per adolescent on the delivery of alcohol interventions. For every dollar spent on alcohol interventions aimed at adolescents, it is estimated that the government receives around $7 in alcohol tax revenue. Conclusions: A substantial disparity exists between the amount of tax revenue received by the Australian Government from adolescent drinkers and the overall amount spent in attempting to prevent and relieve some of the problems associated with adolescent problem drinking. (c) 2006 Elsevier Ltd. All rights reserved.

Prognostic indicators for open globe injury

Background: The purpose of the study is to identify factors predictive of outcome after open globe injury in 273 patients admitted to the Royal Brisbane Hospital, Queensland, Australia between 1992 and 2003. Methods: Data were collected retrospectively regarding demographic and geographical factors, injury circumstances, initial visual acuity (VA), injury parameters, details of initial and subsequent surgery, final best corrected VA and complications. Multivariate analysis using binary logistic regression was utilized to identify which factors were related to outcome. Results: 83% of patients were male, with a mean age of 38.3 years. The mean duration of follow up was 16.6 months and 58% of patients (135 of 231) achieved an overall improvement in their vision. Forty-one cases (15%) were enucleated, with half of these cases performed primarily. The prognostic factors indicating the likelihood of a VA of counting fingers or worse were poor initial VA, a large laceration > 10 mm and the presence of a relative afferent pupil defect. Rural patients had a significantly worse final VA than city dwellers and had higher rates of endophthalmitis and enucleation. Conclusions: Assessment of prognostic factors at the time of presentation of an open globe injury enables realistic expectations of final visual outcome by the doctor and the patient. In order to improve outcomes in patients from rural areas, access to specialized eye services need to be upgraded.

Temporal variation in habitat use by nekton in a subtropical estuarine system

Utilisation by fish of different estuarine habitats is known to vary at many different temporal scales, however no study to date has examined how utilisation varies at all the relevant times scales simultaneously. Here, we compare the utilisation by fish of sandy, intertidal foreshore habitats in a subtropical estuary at four temporal scales: between major spawning periods (spring/ summer and winter), among months within spawning periods, between the full and new moon each month, and between night and day within those lunar phases. Comparisons of assemblage composition, abundance of individuals and of fish in seven different,ecological guilds' were used to identify the temporal scales at which fish varied their use of unvegetated sandy habitats in the lower Noosa Estuary, Queensland, Australia. Fish assemblages were sampled with a seine net at three different regions. The most numerically dominant species caught were southern herring (Herklotsichthys castelnaui: Clupeidae), sand whiting (Sillago ciliata: Sillaginidae), weeping toadfish (Torquigener pleurogramma: Tetraodomidae), and silver biddy (Gerres subfasciatus: Gerreidae). Considerable variation at a range of temporal scales from short term (day versus night) to longer term (spawning periods) was detected for all but one of the variables examined. The clearest patterns were observed for diurnal effects, where generally abundance was greater at night than during the day. There were also strong lunar effects, although there were no consistent patterns between full moon and new moon periods. Significant differences among months within spawning periods were more common than differences between the actual spawning periods. The results clearly indicate that utilisation of sandy, unvegetated estuarine habitats is very dynamic and highly variable in space and time. (c) 2006 Elsevier B.V. All rights reserved.

The importance of host ecology in thelastomatoid (Nematoda : Oxyurida) host specificity

An experimental investigation of host specificity within the Thelastomatoidea is presented by means of a comparison of the thelastomatoids of two panesthiine cockroaches, Panesthia cribrata and R tryoni tryoni, with those of other log-dwelling arthropods and those of leaf litter dwelling arthropods found near by. 145 log-dwelling and leaf-litter dwelling arthropods, representing adjacent ecological niches, were collected from Lamington National Park, Queensland, Australia. A high degree of thelastomatoid species sharing (19 incidences from 26 specimens) occurs between log-dwelling arthropods and the two cockroach species. No overlap in thelastomatoid fauna was observed between the log dwelling and leaf-litter dwelling groups. Our results suggest that host specificity of thelastomatoids is largely dictated by host ecology. (c) 2006 Elsevier Ireland Ltd. All rights reserved.

The origin of modern crocodyliforms: new evidence from the Cretaceous of Australia

While the crocodyliform. lineage extends back over 200 million years (Myr) to the Late Triassic, modern forms - members of Eusuchia - do not appear until the Cretaceous. Eusuchia includes the crown group Crocodylia, which comprises Crocodyloidea, Alligatoroidea and Gavialoidea. Fossils of non-crocodylian eusuchians are currently rare and, in most instances, fragmentary. Consequently, the transition from Neosuchia to Crocodylia has been one of the most poorly understood areas of crocodyliform evolution. Here we describe a new crocodyliform from the mid-Cretaceous (98-95 Myr ago; Albian-Cenomanian) Winton Formation of Queensland, Australia, as the most primitive member of Eusuchia. The anatomical changes associated with the emergence of this taxon indicate a pivotal shift in the feeding and locomotor behaviour of crocodyliforms - a shift that may be linked to the subsequent rapid diversification of Eusuchia 20 Myr later during the Late Cretaceous and Early Tertiary. While Laurasia (in particular North America) is the most likely ancestral area for Crocodylia, the biogeographic events associated with the origin of Eusuchia are more complex. Although the fossil evidence is limited, it now seems likely that at least part of the early history of Eusuchia transpired in Gondwana.

Theft of bower decorations among male Satin Bowerbirds (Ptilonorhynchus violaceus): why are some decorations more popular than others?

Male Satin Bowerbirds (Ptilonorhynchus violaceus) build stick structures known as bowers that serve as the focus for courtships and matings. Males decorate their bowers with numerous coloured decorations and are known to steal these decorations from one another. We investigated the stealing of bower decorations among males at the Bunya Mountains in Queensland, Australia. We aimed to (1) determine which classes of decorations were targets for theft in the studied population, and (2) examine whether the frequency at which individual decorations were stolen related to their intrinsic properties. To address our first aim, all decorations on the bowers of 21 adult males were labelled and their movements tracked throughout one mating season. To address our second aim, decorations stolen at least three times during the season were collected and their morphological and reflectance properties compared to those of decorations that were not stolen. In terms of the classes of decorations, tail feathers of Crimson Rosella (Platycercus elegans) were stolen more than any other class of decoration, but blue plastic bottletops were the most popular decorations relative to their availability on bowers. Frequently stolen individual decorations were similar to non-stolen items in their weights and surface areas, but were darker blue in colour than the decorations never stolen. Both bottletops and feathers reflected higher levels of ultraviolet (UV) light than did all other classes of bower decorations tested, thus suggesting that males may be using UV reflectance in sexual signalling. The darker blue, stolen decorations may increase contrast between the decoration collection and the platform, while the UV-reflecting subset of most frequently stolen decorations (bottletops and feathers) may increase contrast within the decoration collection. This in turn may increase the attractiveness of the display to females.

Thelastomatoidea (Nematoda : Oxyurida) of the Australian giant burrowing cockroach, Macropanesthia rhinoceros (Blaberidae : Geoscapheinae)

The thelastomatoid fauna of Macropanesthia rhinoceros was examined from 13 localities across its range in Queensland, Australia. Nine species of thelastomatoids, including two representing new genera, Geoscaphenema megaovum n. g., n. sp. and Jaidenema rhinoceratum n. g., n. sp., were found. Macropanesthia rhinoceros is reported as a new host for seven species previously recorded from Panesthia cribrata (Blaberidae: Panesthiinae) and P. tryoni tryoni, viz, Blattophila sphaerolaima, Leidynemella fusiformis, Cordonicola gibsoni, Travassosinema jaidenae, Coronostoma australiae, Hammerschmidtiella hochi and Desmicola ornata. Overall estimated richness for the system ranged from 10.1-13.5 species. The high degree of parasite faunal overlap between M. rhinoceros and the two Panesthia species is surprising given the disparate ecological niches that they occupy; P. cribrata and P. tryoni tryoni burrow in, and feed upon, moist decaying wood and require a climate that is moist all year round, whereas M. rhinoceros burrows in loose soil, feeds on fallen leaf litter and is tolerant of much drier environments.

Silencing of the ACC synthase gene ACACS2 causes delayed flowering in pineapple [Ananas comosus (L.) Merr.]

Flowering is a crucial developmental stage in the plant life cycle. A number of different factors, from environmental to chemical, can trigger flowering. In pineapple, and other bromeliads, it has been proposed that flowering is triggered by a small burst of ethylene production in the meristem in response to environmental cues. A 1-amino-cyclopropane-1-carboxylate synthase (ACC synthase) gene has been cloned from pineapple (ACACS2), which is induced in the meristem under the same environmental conditions that induce flowering. Two transgenic pineapple lines have been produced containing co-suppression constructs designed to down-regulate the expression of the ACACS2 gene. Northern analysis revealed that the ACACS2 gene was silenced in a number of transgenic plants in both lines. Southern hybridization revealed clear differences in the methylation status of silenced versus non-silenced plants by the inability of a methylation-sensitive enzyme to digest within the ACACS2 DNA extracted from silenced plants, indicating that methylation is the cause of the observed co-suppression of the ACACS2 gene. Flowering characteristics of the transgenic plants were studied under field conditions in South East Queensland, Australia. Flowering dynamics studies revealed significant differences in flowering behaviour, with transgenic plants exhibiting silencing showing a marked delay in flowering when compared with non-silenced transgenic plants and control non-transformed plants. It is argued that the ACACS2 gene is one of the key contributors towards triggering 'natural flowering' in mature pineapples under commercial field conditions.

Habitat use by Darling Downs population of the grassland earless dragon: implications for conservation.

A population of the grassland earless dragon (Tympanocryptis pinguicolla) on the Darling Downs, Queensland, Australia, had been considered extinct until its recent rediscovery. We determined factors affecting grassland earless dragon abundance and prey availability in 3 habitats. Mean dragon body condition and prey numbers were higher in sorghum than grasslands and grass verges. Poisson regression analyses indicated that the dragon numbers were 10 times higher in sorghum, and that this may result from differences in prey numbers as well as other habitat conditions. Tracking data indicated selection of open versus closed microhabitat. Sorghum planted in rows provided alternating open and closed microhabitats for optimal thermoregulation conditions. Grasslands and grass verges were more uniformly shaded. Of individuals we tracked in the sorghum stubble, 85.7% used litter as overnight refuges. Litter was abundant in sorghum and sparse in grass habitats. The practices of minimum tillage and resting stubble strips possibly mitigate agricultural impacts on dragons and provide continuous access to suitable habitat. Changes in agricultural practices that affect the habitat suitability will potentially have detrimental impacts on the population. Our data suggest that conservation efforts be focused on maintaining suitability of habitats in crop fields. We recommend monitoring dragon abundance at control and trial sites of any new agricultural practices; this will provide opportunity to modify or stop undesirable practices before adoption by farmers. Conservation agencies may use our data as a baseline for monitoring long-term viability of the population.

The behaviour of the rare earth elements during estuarine mixing-revisited

Complete rare earth element (except Eu) and Y concentrations from the estuarine mixing zone (salinity =0.2 to 33) of Elimbah Creek, Queensland, Australia, were measured by quadrupole ICP-MS without preconcentration. High sampling density in the low salinity regime along with high quality data allow accurate tracing of the development of the typical marine rare earth element anomalies as well as Y/Ho fractionation. Over the entire estuary, the rare earth elements are strongly removed relative to a freshwater endmember (60-80% removal). This large overall removal occurs despite a strong remineralisation peak (190% for La, 130% for Y relative to the freshwater endmember) in the mid-salinity zone. Removal and remineralisation are accompanied by fractionation of the original (freshwater) rare earth element pattern, resulting in light rare earth element depletion. Estuarine fractionation generates a large positive La anomaly and a superchondritic Y/Ho ratio. Conversely, we observe no evidence to support the generation of the negative Ce anomaly in the estuary. With the exception of Ce, the typical marine rare earth element features can thus be attributed to estuarine mixing processes. The persistence of these features in hydrogenous sediments for at least 3.71 Ga highlights the importance of estuarine processes for marine chemistry on geological timescales. (c) 2005 Elsevier B.V. All rights reserved.

Aquatic geochemistry of the rare earth elements and yttrium in the Pioneer River catchment, Australia

The rare earth elements are strong provenance indicators in geological materials, yet the potential for tracing provinciality in surface freshwater samples has not been adequately tested. Rare earth element and yttrium concentrations were measured at 33 locations in the Pioneer River catchment, Mackay, central Queensland, Australia. The rare earth element patterns were compared on the basis of geological, topographical and land-use features in order to investigate the provenancing potential of these elements in a small freshwater system. The rare earth element patterns of streams draining single lithological units with minor land modification show strongly coherent normalised behaviour, with a loss of coherence in agricultural locations. Evidence is reported for an anthropogenic Gd anomaly that may provide a useful hydrological tracer in this region since the introduction of magnetic resonance imaging in 2003. Several samples display a superchondritic Y/Ho mass ratio (up to 44), which is not explainable within the constraints imposed by local geology. Instead, it is suggested that the additional Y is derived from a marine source, specifically marine phosphorites, which are a typical source of fertiliser phosphorus. The data indicate that, under some circumstances, scaled and normalised freshwater rare earth patterns behave conservatively.