Field evaluation of a suite of biomarkers in an Australian Tropical Reef Species, Stripey Seaperch (Lutjanus carponotatus) : Assessment of Produced Formation water from the Harriet A Platform

There is paucity of data regarding hydrocarbon exposure of tropical fish species inhabiting the waters near oil and gas platforms on the Northwest Shelf of Australia. A comprehensive field study assessed the exposure and potential effects associated with the produced water (PW) plume from the Harriet A production platform on the northwest shelf in a local reef species, Stripey seaperch (<i>Lutjanus carponotatusi>). This field study was a continuation of an earlier pilot study which concluded that there were &ldquo;warning signs” of potential biological effects on fish populations exposed to PW. A 10-day field caging study was conducted deploying 15 individual fish into 6 separate steel cages set 1-m subsurface at 3 stations in a concentration gradient moving away from the platform. A battery of biomarkers were evaluated including hepatosomatic index (HSI), total cytochrome P450, bile metabolites, CYP1A-, CYP2K- and CYP2M-like proteins, cholinesterase (ChE) activity, and histopathology of liver and gill tissues. Water column and PW effluent samples was also collected. Results confirmed that PAH metabolites in bile, CYP1A-, CYP2K-, and CYP2M-like proteins and liver histopathology provided evidence of significant exposure and effects after 10 days at the near-field site (~200 m off the Harriet A platform). Hepatosomatic index, total cytochrome P450, and ChE did not provide site-specific differences by day 10 of exposure to PW. CYP proteins were shown by principal component analysis (PCA) to be the best diagnostic tool for determining exposure and associated biological effects of PW on <i>L. carponotatusi>. Using a suite of biomarkers has been widely advocated as a vital component in environmental risk assessments worldwide. This study demonstrates the usefulness of biomarkers for assessing the Harriet A PW discharge into Australian waters with broader applications for other PW discharges. This approach has merit as a valuable addition to environmental management strategies for protecting Australia’s tropical environment and its rich biodiversity.

A novel monotonic fixed-point algorithm for l1-regularized least square vector and matrix problem

Least square problem with<i> l</i>₁ regularization has been proposed as a promising method for sparse signal reconstruction (e.g., basis pursuit de-noising and compressed sensing) and feature selection (e.g., the Lasso algorithm) in signal processing, statistics, and related fields. These problems can be cast as <i>l</i>₁-regularized least-square program (LSP). In this paper, we propose a novel monotonic fixed point method to solve large-scale <i>l</i>₁-regularized LSP. And we also prove the stability and convergence of the proposed method. Furthermore we generalize this method to least square matrix problem and apply it in nonnegative matrix factorization (NMF). The method is illustrated on sparse signal reconstruction, partner recognition and blind source separation problems, and the method tends to convergent faster and sparser than other<i> l</i>₁-regularized algorithms.

Biennial reproductive cycle in an extensive matrotrophic viviparous batoid : the sandyback stingaree Urolophus bucculentus from south-eastern Australia

<i>Urolophus bucculentusi>, the largest urolophid species found in southern Australia, exhibits a biennial reproductive cycle. Ovulation occurs during October to January followed by a 15–19 month period of gestation followed by parturition during April to May and a short rest period while the ovarian follicles continue to develop for subsequent ovulation. Male breeding condition peaks during April to June to coincide with the period of parturition. <i>Urolophus bucculentusi> has the highest matrotrophic contribution reported for any urolophid species, with a mean wet mass gain from egg <i>in uteroi> (4 g) to full-term embryo <i>in uteroi> (250 g) of <i>c.i> 6250% (maximum c. 7200%), and perhaps explains the biennial female reproductive cycle where 50% of females contribute to each year's recruitment. Litter size (one to five) increases with total length (<i>L<sub>Ti>). Females reach a longer maximum L<sub>T (<i>L</i>_Tmax) than do males (885 v. 660 mm). The <i>L</i>_T at maturity for males and females at 50% mature (<i>L</i>_T50) is c. 414 mm (63% of <i>L</i>_Tmax) for males and c. 502 mm (57% of <i>L</i>_Tmax) for females, length at maternity indicates that recruitment production occurs later in life at <i>ci>. 632 mm <i>L</i>_T (71% of <i>L</i>_Tmax).

Defining plant resistance to Phytophthora cinnamomi : a standardized approach to assessment

<i>Phytophthora cinnamomi i>is a soil-borne plant pathogen that causes devastating disease in agricultural and natural systems worldwide. While a small number of species survive infection by the pathogen without producing disease symptoms, the nature of resistance, especially under controlled conditions, remains poorly understood. At present, there are no standardized criteria by which resistance or susceptibility to<i> P. cinnamomi i>can be assessed, and we have used five parameters consisting of plant fresh weight, root growth, lesion length, relative chlorophyll content of leaves and pathogen colonization of roots to analyse responses to the pathogen. The parameters were tested using two plant species, <i>Zea mays i>and <i>Lupinus angustifoliusi>, through a time course study of the interactions and resistance and susceptibility defined 7days after inoculation. A scoring system was devised to enable differentiation of these responses. In the resistant interaction with <i>Z. maysi>, there was no significant difference in fresh weight, root length and relative chlorophyll content in inoculated compared with control plants. Both lesion size and pathogen colonization of root tissues were limited to the site of inoculation. Following inoculation <i>L. angustifoliusi> showed a significant reduction in plant fresh weight and relative leaf chlorophyll content, cessation of root growth and increased lesion lengths and pathogen colonization. We propose that this technique provides a standardized method for plant-<i>P. cinnamomi i>interactions that could be widely used to differentiate resistant from susceptible species.

Talking books for children's home use in a minority Indigenous Australian language context

Members of the Kunibidji community are the traditional owners of the lands and seas around Maningrida, a remote community in Northern Australia. Most of the 200 members of the Kunibidji Community speak Ndjebbana as their first language. This study reports on the complexities of transforming technology to provide Kunib&iacute;dji children with access to digital texts at home. The printed Ndjebbana texts that were kept at school were transformed to Ndjebbana talking books displayed on touch screen computers in the children's homes. Some results of the children's interaction around these touch screens are presented as well as some quantitative results of the computer viewing in the homes. The processes of rejecting technological determinism, upholding linguistic human rights of speakers of minority languages and viewing technology as practice rather than a set of artefacts are discussed in this paper. The results of this study highlight the need for speakers of minority Indigenous Australian languages to have access to texts in their threatened languages on technologies at home.

Engineering a multimodal nerve conduit for repair of injured peripheral nerve

Injury to nerve tissue in the peripheral nervous system (PNS) results in long-term impairment of limb function, dysaesthesia and pain, often with associated psychological effects. Whilst minor injuries can be left to regenerate without intervention and short gaps up to 2 cm can be sutured, larger or more severe injuries commonly require autogenous nerve grafts harvested from elsewhere in the body (usually sensory nerves). Functional recovery is often suboptimal and associated with loss of sensation from the tissue innervated by the harvested nerve. The challenges that persist with nerve repair have resulted in development of nerve guides or conduits from non-neural biological tissues and various polymers to improve the prognosis for the repair of damaged nerves in the PNS. This study describes the design and fabrication of a multimodal controlled pore size nerve regeneration conduit using polylactic acid (PLA) and (PLA):poly(lactic-co-glycolic) acid (PLGA) fibers within a neurotrophin-enriched alginate hydrogel. The nerve repair conduit design consists of two types of PLGA fibers selected specifically for promotion of axonal outgrowth and Schwann cell growth (75:25 for axons; 85:15 for Schwann cells). These aligned fibers are contained within the lumen of a knitted PLA sheath coated with electrospun PLA nanofibers to control pore size. The PLGA guidance fibers within the nerve repair conduit lumen are supported within an alginate hydrogel impregnated with neurotrophic factors (NT-3 or BDNF with LIF, SMDF and MGF-1) to provide neuroprotection, stimulation of axonal growth and Schwann cell migration. The conduit was used to promote repair of transected sciatic nerve in rats over a period of 4 weeks. Over this period, it was observed that over-grooming and self-mutilation (autotomy) of the limb implanted with the conduit was significantly reduced in rats implanted with the full-configuration conduit compared to rats implanted with conduits containing only an alginate hydrogel. This indicates return of some feeling to the limb via the fully-configured conduit. Immunohistochemical analysis of the implanted conduits removed from the rats after the four-week implantation period confirmed the presence of myelinated axons within the conduit and distal to the site of implantation, further supporting that the conduit promoted nerve repair over this period of time. This study describes the design considerations and fabrication of a novel multicomponent, multimodal bio-engineered synthetic conduit for peripheral nerve repair.