Assessing the potential for restocking the western school prawn Metapenaeus dalli in a temperate Australian estuary

The population dynamics of restocking involves trade-offs between different release scenarios and the conservation of wild stocks and evaluating these trade-offs is an important component of restocking programs. This study used length frequency data and mixture analysis to estimate growth, mortality and reproductive parameters for the western school prawn Metapenaeus dalli in the Swan-Canning Estuary. These biological parameters provide the first quantitative estimates of growth and mortality for M. dalli and were used as inputs into a bioeconomic model developed with the EnhanceFish software used to evaluate the effectiveness of different stocking levels and sizes-at-release. This research had two primary objectives: 1) To use the data from a spatially and temporally comprehensive sampling program for M. dalli in the Swan-Canning Estuary to determine the biological parameters for growth, mortality and size at maturity; and 2) Develop a bioeconomic model using the EnhanceFish software to evaluate the potential increase in population biomass from restocking with different numbers of released prawns and different sizes-at-release. Monthly length frequency data demonstrated that M. dalli exhibits strong seasonal growth and reproductive cycles. Growth was estimated using Somers (1988) seasonal adaptation of the von Bertalanffy growth curve. This analysis demonstrated that females grew significantly larger (L∞ = 33.72 mm CL, k = 1.06) than males (L∞ = 24.20 mm CL, k = 0.97). Gravid females, or females carrying a spermatophore, were only found between November and April, when surface and bottom water temperatures were between 20 and 27 ºC. Pauly’s (1983a, b, 1984) seasonal catch-curve revealed little difference in total instantaneous mortality between female and males (Z = 0.048 and 0.047 week-1, respectively). Whereas Pauly’s (1990) non- seasonal catch-curve showed a larger range in mortality between females (0.067 week-1) and males and (0.052 week-1). Since recreational fishing effort and thus fishing mortality is very low, these estimates provide a close approximation for natural mortality (M) in the population. The patterns of growth and reproduction were compared with those recorded in this system ≈ 30 years ago by Potter et al. (1986), who found a similar seasonal pattern of growth. However, the maximum size of prawns recorded in that study were about 10% smaller and the estimates of L∞ about 20 % smaller than those from the current sampling. These differences indicate that the far greater fishing pressure in this earlier period may have selectively removed larger prawns from the population. The release scenarios evaluated by the bioeconomic model varied from 650,000 to 5 million prawns (i.e. 650,000, 1 million, 2 million and 5 million) and the size-at-release from 1 mm carapace length (CL) to 10 mm CL. The greatest potential returns were obtained when 5 million prawns were released at a size of 10 mm CL, however, such an aquaculture effort would require substantial capital expenditure in order to produce the required number of juveniles. The model results also highlighted that density-dependent processes are likely to be important and decrease the relative effectiveness of releases. At the current low population level and without any restocking, the population biomass was projected to remain virtually unchanged over a five-year period. The model results also highlight the need for empirical information on natural morality, the influence of density on growth and survival and how time-at-release might influence survival. These results improve our biological understanding of M. dalli and will be used to help plan any future restocking of this species in the Swan-Canning Estuary

Cytomegalovirus as a driver of excess cardiovascular mortality in rheumatoid arthritis: a red herring or a smoking gun?

Rheumatoid arthritis (RA) is the most common inflammatory arthritis worldwide. Apart from its well known manifestations involving the joints (e.g. deformity, swelling, synovial inflammation), there are widespread, extra-articular manifestations that also involve the cardiovascular (CV) system. The consequences of CV involvement are often serious; cerebrovascular disease, ischemic heart disease and CV disease (CVD)-associated death are up to 50% higher in the context of RA leading to a reduction of life-expectancy in these patients of 3-10 years compared with the general population. To date, no satisfactory explanation of this phenomenon has been found, or maybe, it has been overlooked

Improving the nutritional management of non-astringent persimmon in subtropical Australia

A series of experiments was conducted to evaluate the nutritional requirements of non-astringent persimmon in subtropical Australia. Three rates two times of application of the two major nutrients, N and K, were evaluated for two different soil types in south-east Queensland. Nitrogen and K were shown to be key manipulators of productivity. At both low (100 kg per hectare) annual rates of N, the total number of fruit per tree was reduced due to adverse effects on fruit set and increased fruit drop. With potassium, average fruit weight and yield increased with increasing rates of K applied up to 80 kg per hectare, and much more slowly thereafter. Multiple, sequential foliar applications of Ca were shown to increase leaf Ca concentrations by 20%, improve fruit firmness and storage life. A benchmarking survey of leading orchards was also undertaken to document current nutritional practices, and to determine if there was a relationship between leaf nutrient concentrations with productivity. Salinity was a major problem in some production regions; and at leaf CI concentrations above 0.8%, yield was severely reduced. Based on these studies, a new, narrower range of leaf nutrient standards at both fruit set and one month prior to harvest is being developed

A Survey of Cultivars and Management Practices in Australian Persimmon Orchards

Three surveys were conducted to determine the most commonly used cultivars and management practices across Australia. The persimmon industry is established from the semi-tropical far north of Queensland to the cool temperate zones of Victoria, South Australia and Western Australia. Fruit from warmer regions mature four months earlier, giving a harvest spread from February to June inclusive. The majority of the Australian industry is based on the non-astringent cultivar Fuyu. Only 26% of Australian orchards are planted with pollinizers. Yield and fruit size vary within and between regions. Factors contributing to lower yields and smaller size grades are temperature, salinity, pollination, and training and management systems. The most common tree training system is the freestanding vase, followed by palmette, the V- and Tatura trellises. Ruakura trellis is the least used. Trellised trees produce higher yields of marketable fruit through increased planting density, improved light interception and a tree structure that stabilises against tree movement, significantly reducing fruit blemish

Shoot yield drives phosphorus use efficiency in Brassica oleracea and correlates with root architecture traits

The environmental and financial costs of using inorganic phosphate fertilizers to maintain crop yield and quality are high. Breeding crops that acquire and use phosphorus (P) more efficiently could reduce these costs. The variation in shoot P concentration (shoot-P) and various measures of P use efficiency (PUE) were quantified among 355 Brassica oleracea L. accessions, 74 current commercial cultivars, and 90 doubled haploid (DH) mapping lines from a reference genetic mapping population. Accessions were grown at two or more external P concentrations in glasshouse experiments; commercial and DH accessions were also grown in replicated field experiments. Within the substantial species-wide diversity observed for shoot-P and various measures of PUE in B. oleracea, current commercial cultivars have greater PUE than would be expected by chance. This may be a consequence of breeding for increased yield, which is a significant component of most measures of PUE, or early establishment. Root development and architecture correlate with PUE; in particular, lateral root number, length, and growth rate. Significant quantitative trait loci associated with shoot-P and PUE occur on chromosomes C3 and C7. These data provide information to initiate breeding programmes to improve PUE in B. oleracea

Forage grasses with lower uptake of casesium and strontium could provide 'safer' crops for radiologically contaminated areas

Substitution of a species or cultivar with higher uptake of an element by one with lower uptake has been proposed as a remediation strategy following accidental releases of radioactivity. However, despite the importance of pasture systems for radiological dose, species/cultivar substitution has not been thoroughly investigated for forage grasses. 397 cultivars from four forage grass species; hybrid ryegrass (Lolium perenne L. x Lolium multiflorum Lam.), perennial ryegrass (Lolium perenne L.), Italian ryegrass (Lolium multiflorum Lam.) and tall fescue (Festuca arundinacea Shreb.); were sampled from 19 field-based breeding experiments in Aberystwyth and Edinburgh (UK) in spring 2013 and analysed for caesium (Cs) and strontium (Sr) concentrations. In order to calculate concentration ratios (CRs; the concentration of an element in a plant in relation to the concentration in the soil), soils from the experiments were also analysed to calculate extractable concentrations of Cs and Sr. To test if cultivars have consistently low Cs and Sr concentration ratios, 17 hybrid ryegrass cultivars were sampled from both sites again in summer 2013 and spring and summer 2014. Tall fescue cultivars had lower Cs and Sr CRs than the other species. Three of the selected 17 hybrid ryegrass cultivars had consistently low Cs CRs, two had consistently low Sr CRs and one had consistently low Cs and Sr CRs. Cultivar substitution could reduce Cs CRs by up to 14-fold and Sr CRs by 4-fold in hybrid ryegrass. The identification of species and cultivars with consistently low CRs suggests that species or cultivar substitution could be an effective remediation strategy for contaminated areas

Do agronomic approaches aligned to regenerative agriculture improve the micronutrient concentrations of edible portions of crops? A scoping review of evidence

Regenerative Agriculture (RA) is used to describe nature-based agronomic approaches that aim to build soil health and crop resilience, minimize negative environmental outcomes, and improve farmer livelihoods. A benefit that is increasingly attributed to crops grown under RA practices is improved nutritional content. However, we do not know the extent to which RA influences crop nutritional quality and under what management approaches and context, can such effects be realized. A scoping review of recent literature (Web of Science, 2000-2021) was carried out to assess the evidence that RA approaches improve crop micronutrient quality. Papers included combinations of agronomic approaches that could be defined as Regenerative: "Organic Inputs" including composts and manures, cover crops, crop rotations, crop residues and biochars; "Reduced Tillage", "Intercropping", "Biostimulants" e.g. arbuscular mycorrhizal fungi; plant growth promoting bacteria, and "Irrigation", typically deficit-irrigation and alternate wetting and drying. The crop types reviewed were predetermined covering common sources of food and included: Tomato (Solanum lycopersicum L.), Wheat (Triticum aestivum L.), Rice (Oryza sativa L.), Maize (Zea mays L.), Pulses (Fabaceae), Alliums (Allium spp.), and "other" crop types (30 types). This scoping review supports a potential role for RA approaches in increasing the concentrations of micronutrients in the edible portions of several crop types under specific practices, although this was context specific. For example, rice grown under increased organic inputs showed significant increases in grain zinc (Zn) concentration in 15 out of 16 studies. The vitamin C concentration of tomato fruit increased in similar to 50% of studies when plants were grown under increased organic inputs, and in 76% of studies when plants were grown under deficit irrigation. Overall, the magnitude and reproducibility of the effects of RA practices on most crop nutritional profiles were difficult to assess due to the diversity of RA approaches, geographical conditions, and the limited number of studies for most crops in each of these categories. Future research with appropriate designs, improved on-farm surveillance and nutritional diagnostics are needed for better understanding the potential role of RA in improving the quality of food, human nutrition, and health

Diagnosis of vertebral fractures in children: is a simplified algorithm-based qualitative technique reliable?

Background Identification of osteoporotic vertebral fractures allows treatment opportunity reducing future risk. There is no agreed standardised method for diagnosing paediatric vertebral fractures. Objective To evaluate the precision of a modified adult algorithm-based qualitative (ABQ) technique, applicable to children with primary or secondary osteoporosis. Materials and methods Three radiologists independently assessed lateral spine radiographs of 50 children with suspected reduction in bone mineral density using a modified ABQ scoring system and following simplification to include only clinically relevant parameters, a simplified ABQ score. A final consensus of all observers using simplified ABQ was performed as a reference standard for fracture characterisation. Kappa was calculated for interobserver agreement of the components of both scoring systems and intraobserver agreement of simplified ABQ based on a second read of 29 randomly selected images. Results Interobserver Kappa for modified ABQ scoring for fracture detection, severity and shape ranged from 0.34 to 0.49 Kappa for abnormal endplate and position assessment was 0.27 to 0.38. Inter- and intraobserver Kappa for simplified ABQ scoring for fracture detection and grade ranged from 0.37 to 0.46 and 0.45 to 0.56, respectively. Inter- and intraobserver Kappa for affected endplate ranged from 0.31 to 0.41 and 0.45 to 0.51, respectively. Subjectively, observers’ felt simplified ABQ was easier and less time-consuming. Conclusion Observer reliability of modified and simplified ABQ was similar, with slight to moderate agreement for fracture detection and grade/severity. Due to subjective preference for simplified ABQ, we suggest its use as a semi-objective measure of diagnosing paediatric vertebral fracture

Diagnostic accuracy of DXA compared to conventional spine radiographs for the detection of vertebral fractures in children

Objectives In children, radiography is performed to diagnose vertebral fractures and dual energy x-ray absorptiometry (DXA) to assess bone density. In adults, DXA assesses both. We aimed to establish whether DXA can replace spine radiographs in assessment of paediatric vertebral fractures. Methods Prospectively, lateral spine radiographs and lateral spine DXA of 250 children performed on the same day were independently scored by three radiologists using the simplified algorithm based qualitative technique and blinded to results of the other modality. Consensus radiograph read and second read of 100 random images were performed. Diagnostic accuracy, inter/intraobserver and intermodality agreements, patient/carer experience and radiation dose were assessed. Results Average sensitivity and specificity (95% confidence interval) in diagnosing one or more vertebral fractures requiring treatment was 70% (58%-82%) and 97% (94%- 100%) respectively for DXA and 74% (55%-93%) and 96% (95%-98%) for radiographs. Fleiss’ kappa for interobserver and average kappa for intraobserver reliability were 0.371 and 0.631 respectively for DXA and 0.418 and 0.621 for radiographs. Average effective dose was 41.9µSv for DXA and 232.7µSv for radiographs. Image quality was similar. Conclusion Given comparable image quality and non-inferior diagnostic accuracy, lateral spine DXA should replace conventional radiographs for assessment of vertebral fractures in children