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The potential for copper slag waste as a resource for a circular economy: A review – Part I
No full textThe mining industry faces a number of challenges that include rapid depletion of high-grade deposits, high energy cost for metal production, and growing environmental concerns associated with mining waste disposal. Copper slag is one of the mining wastes that is raising growing concern due to the huge volumes being produced and dumped annually worldwide. These huge quantities of slag not only cause environmental pollution and space problems for disposal, but they also waste valuable copper and cobalt. This is increasingly important due to the growing demand for these metals in emerging technologies, potentially resulting in a supply deficit from conventional mining production. To address these challenges, recycling and repurposing of copper slag waste using innovative technologies should be considered, creating a resource for a circular economy. This paper presents a review of copper slag production and its potential as a world resource for cobalt and copper metals. An overview of copper and cobalt production from ore reserves, and of global demand and supply risks for these metals is presented. The potential benefits of reprocessing copper slag waste using the circular economy model are discussed. This paper demonstrates that applying the circular economy principles to the copper slag waste has the potential to create additional economic value, improve the energy efficiency of the metal production, increase the supply of critical metals, and reduce the impacts of metal production on the environment
A survey of calf rearing practices in the south-west region of Western Australia
No full textAims
To gather data on the calf management and rearing practices of a subset of dairy farmers in the south-west region of Western Australia.
Methods
A 30-minute face-to-face survey was conducted with dairy cattle producers in the south-west region of Western Australia from April–June 2019 to determine pre-weaning calf rearing practices. Participation was voluntary, using a self-selected subset of dairy farmers registered with a regional extension group. The questionnaire assessed three broad categories: farm demographics, colostrum harvesting and management and calf rearing practices.
Results
The study response rate was 34/140 (24%). The following key areas were identified where there were deviations from recognised best practice: Precalving: no transition diet was fed pre-calving on 4/34 (12%) of farms, and on a further 5/34 (15%) it was fed for less than 3 weeks; mixing of heifers and adult cows in the calving paddocks occurred in 24/34 (70%) of the farms, with 15% (5/34) of the farms using calving induction. During calving 14/34 (41%) of the farms did not disinfect navels of new-born calves; although 23/34 farmers stated that they collected calves within 6 hours of birth, data on frequency of calf pick-up (2/34 did not separate calves and dams and 19/34 picked up only once per day) indicated that on 21/34 farms (62%) the reality was that calves were picked up >12 hours after birth. Colostrum quality was not assessed appropriately on 18/34 (53%) farms and farmers overestimated how soon after birth it was administered: 23/34 (68%) reported feeding it within 6 hours of calving, despite 62% picking up calves >12 hours after calving. Regarding calf rearing practices, no pain relief before or after dehorning was used on 20/34 (59%) farms, calf bedding was removed infrequently (<weekly) on 26/35 (76%) farms and appropriate isolation of sick calves was only reported by 14/34 (41%) farmers.
Conclusion and clinical relevance
Although limited by the low response rate, this is the first survey of dairy calf rearing practices in the south-western region of Western Australia. We found evidence of at least one process inconsistent with industry best-practice on 34/140 (24%) of responding farms and all farms had more than one sub-optimal calf rearing practice. This highlights the need to improve calf rearing in this region and identifies key areas of deficiency for further study and extension to producers
Effect of Non-linear Co-efficient of a hexagonal PCF depending on effective area
No full textA photonic crystal fiber (PCF) is an optical fiber that gets the waveguide characteristics from an array of very small and tightly separated air holes that run the length of the fiber rather than from a spatially changing glass structure. These air holes can be created by stacking capillary and/or solid tubes and implanting those into a bigger tube, or even by utilizing a preform containing holes. PCFs have a wide range of characteristics. One of these is the non-linear co-efficient. This property is influenced by factors such as effective area, pitch size, and so on. The overall goal of this study is to develop and improve the optical characteristics of PCFs and to design a hexagonal PCF for wideband near-zero dispersion-flattened features for dispersion managed applications. The non-linear co-efficient of the hexagonal PCF with respect to effective area is also calculated here
Corrigendum to: Distribution and foraging by non-breeding Caspian Terns on a large temperate estuary of south-western Australia - preliminary investigations
No full textThis study investigates the distribution, abundance, and foraging ecology of Caspian Terns, Hydroprogne caspia, during 5 months of their non-breeding season, in the Peel-Harvey Estuary, south-western Australia. Observations were carried out at 20 sites around the estuary and 6 main areas (13 sites) where terns were abundant. Terns were observed every hour over 5h time-blocks in the morning, midday, and afternoon, and the number of birds, number of birds foraging and time spent foraging were recorded for 10min on the hour. From the 760h of observation, a single overnight roosting site was identified in November, where a maximum of 147 birds were counted in February, after which time the roosting site appeared to shift. The total number of terns, foragers and proportion of time foraging varied amongst the six areas and foraging activity differed amongst times of day. Two areas, both characterised by large, sandy spits adjacent to shallow water, one adjacent to a river mouth and one near an ocean channel, were particularly important for terns and their foraging. Foraging activity was higher in the morning than at other times of day. Although salinity, air temperature, water temperature and wind speed were correlated with the total terns, foragers and proportion of time foraging, the correlations accounted for <25% of the total variation explained. The results of this study provide information for evaluating the use of Caspian Terns as bio-indicators of the Peel-Harvey Estuary and highlights the importance of this system during the non-breeding period
Identification of biomarker volatile organic compounds released by three stored-grain insect pests in wheat
Get PDFMonitoring and early detection of stored-grain insect infestation is essential to implement timely and effective pest management decisions to protect stored grains. We report a reliable analytical procedure based on headspace solid-phase microextraction coupled with gas chromatography–mass spectrometry (HS-SPME-GC-MS) to assess stored-grain infestation through the detection of volatile compounds emitted by insects. Four different fibre coatings were assessed; 85 µm CAR/PDMS had optimal efficiency in the extraction of analytes from wheat. The headspace profiles of volatile compounds produced by Tribolium castaneum (Herbst), Rhyzopertha dominica (Fabricius), and Sitophilus granarius (Linnaeus), either alone or with wheat, were compared with those of non-infested wheat grains. Qualitative analysis of chromatograms showed the presence of different volatile compound profiles in wheat with pest infestation compared with the wheat controls. Wheat-specific and insect-specific volatile compounds were identified, including the aggregation pheromones, dominicalure-1 and dominicalure-2, from R. dominica, and benzoquinones homologs from T. castaneum. For the first time, the presence of 3-hydroxy-2-butanone was reported from S. granarius, which might function as an alarm pheromone. These identified candidate biomarker compounds can be utilized in insect surveillance and monitoring in stored grain to safeguard our grain products in future
Influence of offshore oil and gas structures on seascape ecological connectivity
Get PDFOffshore platforms, subsea pipelines, wells and related fixed structures supporting the oil and gas (O&G) industry are prevalent in oceans across the globe, with many approaching the end of their operational life and requiring decommissioning. Although structures can possess high ecological diversity and productivity, information on how they interact with broader ecological processes remains unclear. Here, we review the current state of knowledge on the role of O&G infrastructure in maintaining, altering or enhancing ecological connectivity with natural marine habitats. There is a paucity of studies on the subject with only 33 papers specifically targeting connectivity and O&G structures, although other studies provide important related information. Evidence for O&G structures facilitating vertical and horizontal seascape connectivity exists for larvae and mobile adult invertebrates, fish and megafauna; including threatened and commercially important species. The degree to which these structures represent a beneficial or detrimental net impact remains unclear, is complex and ultimately needs more research to determine the extent to which natural connectivity networks are conserved, enhanced or disrupted. We discuss the potential impacts of different decommissioning approaches on seascape connectivity and identify, through expert elicitation, critical knowledge gaps that, if addressed, may further inform decision making for the life cycle of O&G infrastructure, with relevance for other industries (e.g. renewables). The most highly ranked critical knowledge gap was a need to understand how O&G structures modify and influence the movement patterns of mobile species and dispersal stages of sessile marine species. Understanding how different decommissioning options affect species survival and movement was also highly ranked, as was understanding the extent to which O&G structures contribute to extending species distributions by providing rest stops, foraging habitat, and stepping stones. These questions could be addressed with further dedicated studies of animal movement in relation to structures using telemetry, molecular techniques and movement models. Our review and these priority questions provide a roadmap for advancing research needed to support evidence-based decision making for decommissioning O&G infrastructure
Mentoring experienced teachers to change their practice: A sociocultural perspective for professional learning and development
No full textThis longitudinal qualitative research is framed within a sociocultural perspective and examines experienced teachers and their mentor as they changed their practice. The data, sourced from three teacher focus groups, email correspondence and the mentor's reflections are analysed using Rogoff's personal, interpersonal and institutional/community planes. This small-scale study gives insights into the complex nature of professional learning, particularly when teachers are challenging the status quo which creates tensions that need to be addressed. Teachers had real concerns about time to teach the curriculum and complete the research activities. They worried about ‘fitting in’ with colleagues and parent perceptions. A collaborative self-development framework is advocated as a culturally appropriate way of for teachers to continue to learn during their careers, encourage risk taking and innovation
Conventional therapies deplete Brain-Infiltrating adaptive immune cells in a Mouse Model of Group 3 Medulloblastoma implicating Myeloid Cells as favorable immunotherapy targets
Get PDFMedulloblastoma is the most common childhood brain cancer. Mainstay treatments of radiation and chemotherapy have not changed in decades and new treatment approaches are crucial for the improvement of clinical outcomes. To date, immunotherapies for medulloblastoma have been unsuccessful, and studies investigating the immune microenvironment of the disease and the impact of current therapies are limited. Preclinical models that recapitulate both the disease and immune environment are essential for understanding immune-tumor interactions and to aid the identification of new and effective immunotherapies. Using an immune-competent mouse model of aggressive Myc-driven medulloblastoma, we characterized the brain immune microenvironment and changes induced in response to craniospinal irradiation, or the medulloblastoma chemotherapies cyclophosphamide or gemcitabine. The role of adaptive immunity in disease progression and treatment response was delineated by comparing survival outcomes in wildtype C57Bl/6J and in mice deficient in Rag1 that lack mature T and B cells. We found medulloblastomas in wildtype and Rag1-deficient mice grew equally fast, and that craniospinal irradiation and chemotherapies extended survival equally in wildtype and Rag1-deficient mice, suggesting that tumor growth and treatment response is independent of T and B cells. Medulloblastomas were myeloid dominant, and in wildtype mice, craniospinal irradiation and cyclophosphamide depleted T and B cells in the brain. Gemcitabine treatment was found to minimally alter the immune populations in the brain, resulting only in a depletion of neutrophils. Intratumorally, we observed an abundance of Iba1+ macrophages, and we show that CD45high cells comprise the majority of immune cells within these medulloblastomas but found that existing markers are insufficient to clearly delineate resident microglia from infiltrating macrophages. Ultimately, brain resident and peripheral macrophages dominate the brain and tumor microenvironment and are not depleted by standard-of-care medulloblastoma therapies. These populations therefore present a favorable target for immunotherapy in combination with front-line treatments
Toxoplasma gondii is not an important contributor to poor reproductive performance of primiparous ewes from southern Australia: A prospective cohort study
Get PDFBackground
Toxoplasma gondii causes reproductive losses in sheep worldwide, including Australia. The reproductive performance of primiparous ewes is typically lower than for mature, multiparous ewes, and younger ewes are more likely to be immunologically naïve and therefore more susceptible to reproductive disease if T. gondii infection occurs during pregnancy. The aim of this study was to assess the impact of infection with T. gondii on the reproductive performance of primiparous ewes in southern Australia using a prospective cohort study. This will inform the need for targeted control strategies for T. gondii in Australian sheep.
Results
Toxoplasma gondii seropositivity using indirect ELISA was detected at 16/28 farms located across southern Australia. Apparent seropositivity to T. gondii was lower in primiparous ewes (1.1, 95% confidence interval (CI) 0.6, 1.8) compared to mature, multiparous ewes (8.1, 95% CI 6.0, 10.5; P < 0.001). Toxoplasma gondii seroconversion during the gestation and lambing period was confirmed for 11/1097 (1.0, 95% CI 0.5, 1.7) of pregnant primiparous ewes that failed to raise a lamb, and 1/161 (0.6, 95% CI 0.1, 2.9) primiparous ewes with confirmed mid-pregnancy abortion.
Conclusions
Low frequency of detection of T. gondii seroconversion during gestation and low frequency of seropositivity to T. gondii suggests that toxoplasmosis was not an important contributor to reproductive losses in primiparous ewes on farms located over a wide geographical area in southern Australia
