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Conclusions on potential management procedures for seven data-limited fisheries
No full textThe two workshops held in Bogor, Indonesia, synthesised information for seven data-limited fisheries in Indonesia and built an understanding of both evaluating management strategies for fisheries and how to apply the Method Evaluation and Risk Assessment package (MERA). As part of the process, new data assessments of fisheries were tabled, mainly using the length-based spawning potential ratio, which typically found very low stock levels. These findings are consistent with those reported to the Government of Indonesia on the status of stocks across the 11 Fisheries Management Areas (FMAs). For example, in 2011, 35% of stocks were assessed as fully exploited and 38% as overexploited, while in 2017, 39% were reported as fully exploited and 44% as overexploited (e.g. decision number 50/KEPMEN-KP/2017). The findings also highlight the need to better manage the fisheries and implement effective measures to rebuild stocks..
Innovation lesson plan of fertilizer dilemma story for integrated knowledge practicing through Lesson Study
Get PDFThe paper clarified the developing lesson plan of fertilizer dilemma story for integrated knowledge practicing through lesson study. Through the PD program using lesson study, the theoretical framework of dilemma story was adopted to reference of the developing lesson plan. Methodology regarded paradigm. Participants included primary school teachers as team teachers, supervisors, expertise university lecturer, and school director. The primary school teachers as team teachers include a science teacher, a mathematics teacher, a technology teacher, and an art teacher in Nongsonghong district, Khon Kaen, Thailand. The developing lesson plan of fertilizer dilemma story for integrated knowledge practicing through lesson study will be interpreted through document analysis and participant observation. The innovation lesson plan of fertilizer dilemma story for integrated knowledge practicing could be summarized through the outcomes of lesson study design – plan, see, and reflect. The results provided the overview of the lesson plan of fertilizer dilemma story for integrated knowledge practicing that could be viewed through the structuring questions for ethical dilemma fertilizer story and example of dilemma story chemical fertilizer. This study may have implications for development program for integrate the curriculum in Thailand
Underappreciated plant vulnerabilities to heat waves
No full textWith climate change, heat waves are becoming increasingly frequent, intense and broader in spatial extent. However, while the lethal effects of heat waves on humans are well documented, the impacts on flora are less well understood, perhaps except for crops. We summarize recent findings related to heat wave impacts including: sublethal and lethal effects at leaf and plant scales, secondary ecosystem effects, and more complex impacts such as increased heat wave frequency across all seasons, and interactions with other disturbances. We propose generalizable practical trials to quantify the critical bounding conditions of vulnerability to heat waves. Collectively, plant vulnerabilities to heat waves appear to be underappreciated and understudied, particularly with respect to understanding heat wave driven plant die‐off and ecosystem tipping points
School leadership and ‘language games’ in neoliberal times: A critical ethnographic case study of the Independent Public School policy in Western Australia
Get PDFThis thesis is a critical policy ethnography (CPE) of school leaders in three low socio-economic indicator (SEI) government schools in Western Australia (WA) that have achieved Independent Public School (IPS) status under the state’s IPS policy. It draws on the stories of school leaders to understand the logics, processes, and tensions they experience in enacting this policy maneuver, and how it is negotiated and resolved at the school level (Ball, 2003).
The introduction of WA’s IPS policy occurs in the context of a distinct and well-documented shift in the ideological forces driving education policy in the Western world. Such a shift has resulted in the ascendancy of neoliberalism as the dominant discourse within government education policy formation. Further, this shift is clearly evident in responses provided by the school leaders throughout this thesis.
Central to this thesis is the argument that independent or autonomous government schools are part of what Lyotard (1984) terms ‘language games.’ These language games occur within a broader set of neoliberal discourses driven by the idea of ‘homo economicus,’ which governs the ways in which individuals conceive of themselves and society. Such a reconceptualization of homo economicus represents an elemental disruption of democracy as individuals within the neoliberal language game strategize for themselves (Dilts, 2011).
The use of CPE provides an opportunity to locate the daily experiences of school leaders in the context of these broader ideological shifts as it relates to the enactment of the IPS policy at three school sites. Ethnography also allows an anthropological approach to the study through seeking to describe participants’ actions, intentions, motives, and reasons. In selecting this particular methodological approach, the voices of participants are given center stage. CPE is a methodology that critically examines the ways in which official policy discourses constitute the lived realities of individuals. In this case, the formal school leadership is comprised of heads of learning areas, deputy principals and principals.
The thesis makes a specific contribution to research by examining the broader effects of neoliberal language games through the enactment of the IPS policy in WA via a range of primary and secondary sources. In particular, it examines the effect of the enactment of the IPS policy from the perspective of school leaders in socially disadvantaged WA government high schools
Morphological and molecular characterization of Isospora amphiboluri (Apicomplexa: Eimeriidae), a coccidian parasite, in a central netted dragon (Ctenophorus nuchalis) (De Vis, 1884) in Australia
Get PDFAn Isospora species, Isospora amphiboluri, originally described by Canon in 1967 and later by McAllister et al. (1995), was isolated from a central netted dragon (Ctenophorus nuchalis) housed at a wildlife rehabilitation centre in Perth, Western Australia. Sporulated oocysts of Isospora amphiboluri (n = 30) are spherical, 24.2 (26.5–23.0) μm in length and 23.9 (22.4–25.9) μm in width, with a shape index of 1.01. The bilayered oocyst wall is smooth and light-yellow in color. Polar granule, oocyst residuum and micropyle are absent. The sporocysts are lemon-shaped, 15.7 (15.2–18.0) × 10.2 (8.9–11.2) μm, with a shape index (length/width) of 1.53. Stieda and substieda bodies are present, the Stieda body being small and hemidome-shaped and the substieda half-moon-shaped. Each sporocyst contains four vermiform sporozoites arranged head to tail. The sporozoites are 11.7 (9.9–16.2) × 3.0 (2.4–3.5) μm, with a shape index (length/width) of 3.87. A sporocyst residuum is present. Sporozoites contain a central nucleus with a finely distributed granular residuum. Comparison of oocyst measurements and their features with other valid Isospora species from hosts in the Agamid family confirmed that this Isospora species is Isospora amphiboluri. Molecular characterization of I. amphiboluri at the 18S rRNA and MTCOI loci showed the highest similarity with I. amphiboluri from the central bearded dragon, 99.8% and 99.7% respectively. This is the first report of I. amphiboluri from a central netted dragon in Australia
What's in the soup? Visual characterization and polymer analysis of microplastics from an Indonesian manta ray feeding ground
No full textPlastics in marine environments vary in their physical and chemical properties, influencing their risk to biota once ingested. Manta rays are large filter-feeders that ingest plastics. To assess this risk, we characterized the plastics in a critical feeding habitat off Nusa Penida, Indonesia. We examined the color and polymer composition of sampled small-sized plastics (<30 mm). Plastics were mostly secondary microplastics and transparent (46%), white/off-white (24%), and blue/green (22%). Fourier transform infrared spectroscopy of plastics grouped according to type (films, fragments, foam, or lines) and color indicated that most plastics were polyethylene (PE) or polypropylene (PP) (99%), with the remainder polystyrene and polyester. Visual characterization aligned with single polymer composition in seven out of ten groups. Although PE and PP have relatively low toxicity compared to other plastics, their composing monomers and associated pollutants and microbes are of concern to manta rays and other marine biota
Nonlinear speed tracking control of PMSM servo system: A global robust output regulation approach
No full textIt is well known that load torque disturbance and parametric uncertainties commonly exist in permanent magnet synchronous motor (PMSM) and may reduce the tracking accuracy especially when the reference trajectory is time-varying. Thus it is challenging to achieve precise speed tracking control with both load torque disturbance and parametric uncertainties being taken into account. This task can be formulated as a global robust output regulation problem (GRORP) of multi-input, multi-output nonlinear system. In this paper, a systematic internal model control (IMC) method is proposed to solve the GRORP. By constructing a suitable internal model, we convert the GRORP into a global stabilization problem of an augmented system, and then design a stabilization controller to globally stabilize the augmented system. To validate the advantages of the proposed IMC method, comparative studies with conventional proportional–integral speed control method and linear active disturbance rejection control method are conducted via simulations and experiments. It is worthy of mentioning that our method can not only achieve high precision speed tracking performance under time-varying reference speed and/or load torque disturbance, but also allow all the motor parameters to be uncertain
Co-sensitization of natural and low-cost dyes for efficient panchromatic light-harvesting using dye-sensitized solar cells
No full textCo-sensitization is an effective strategy to achieve panchromatic light-harvesting and to enhance dye-sensitized solar cell performance. In this work, the potential of the extracted natural dyes from Malva verticillata and Syzygium cumini was evaluated as mono and co-sensitizers in DSSCs. The UV–vis absorption spectra revealed that the combination of studied dyes had a high molar extinction coefficient and cumulative absorption properties in a way that its absorption spectra overlapped the spectral domain where the original sensitizers lacked light-harvesting. Moreover, all investigated dyes were characterized using circular dichroism, dynamic light scattering, zeta potential, cyclic voltammetry, and Fourier-transform infrared spectroscopy. The results of zeta potential analysis showed that the pigment aggregation and their colloidal stability, which has implications for the pigment adsorption process on TiO2 nanoparticles, were effectively controlled by varying the pH of the dye extract. Based on the CV results, the studied dyes indicated excellent redox stability and sufficient thermodynamic driving force for efficient electron injection. Based on the photovoltaic results, the acidified cocktail-DSSC had the highest and of 3.15 mA and 1.84 %, respectively. This superiority could be ascribed to the panchromatic light-harvesting, the excellent optical activity, and the appropriate energy levels of the acidified cocktail. Moreover, the loading of acidified cocktail dyes on the TiO2 surface was enhanced due to their homogeneous dispersion, less steric hindrances, and multi-anchor groups attached to the semiconductor surface. Based on the stability results, the treated cocktail-DSSC retained about 52.51 % of its as-fabricated efficiency after seven days while NDSSCs sensitized with acidified Syzygium cumini, Malva verticillata, Syzygium cumini, and cocktail retained about 26.24 %, 14.80 %, 16.35 %, and 15.25 %, respectively
Formation mechanisms of surface passivating phases and their impact on the leaching kinetics of sphalerite (ZnS) and galena (PbS)
Get PDFSphalerite (ZnS) and galena (PbS) are the primary sources of zinc and lead, respectively. They often coexist in ore deposits. Extraction of zinc and lead is traditionally achieved by high-temperature roasting and smelting processes in which gaseous SO2 is produced, requiring expensive treatment. Hydrometallurgical leaching such as heap leaching and in situ leaching are environmentally more sustainable due to higher energy efficiency and no release of SO2, but slow leaching rate is the main challenge restricting their wide applications. The leaching rate is significantly affected by the formation of surface passivating phases, but the mechanism is not clearly known.
The objectives of this thesis are to understand the formation mechanisms of surface passivating layers and their impact on the leaching kinetics of sulfide minerals. The thesis has five main research chapters, focusing on (1) leaching of sphalerite in ferric sulfate, ferric chloride, and ferric nitrate and investigating surface passivation mechanisms in each case; (2) leaching of sphalerite in ferric methanesulfonate as a green leaching medium with less impact on the environment; (3) leaching of galena in ferric chloride, ferric perchlorate, and ferric nitrate and studying the formation mechanisms, porosity evolution, and sample textural characterization of the product phases; (4) leaching of galena in acetate-based and citrate-based solutions in the presence of hydrogen peroxide for providing a green and sustainable option for Pb extraction at lower temperatures (25-50 °C); and (5) developing a flow-through cell for in situ PXRD investigations of minerals leaching that provides more accurate insights into the leaching mechanisms.
Leaching residues were analyzed by SEM, EDS, PXRD, EPMA, FIB-SEM-tomography, synchrotron in situ PXRD, and Raman spectroscopy, and leach liquors were characterized by ICP-MS, ICP-OES, and AAS. The experimental results, together with thermodynamic modeling, confirmed that coupled dissolution-reprecipitation mineral replacement reaction was the responsible mechanism for the formation of surface phases and that type of anion significantly affected leaching.
For sphalerite, surface passivation was caused by hydrated Zn-Fe sulfate phases during ferric sulfate leaching and by elemental sulfur during ferric chloride leaching. The presence of these product layers made the effective contact between the mineral surface and leaching solution difficult. Thus, leaching rate became strongly dependent on species diffusion through the product layer. In contrast, no passivation occurred during ferric nitrate and ferric methanesulfonate leaching due to the formation of porous/permeable sulfur, and leaching rate was controlled by surface chemical reaction throughout the process. In addition, the composition of primary sphalerite was an important factor in the oxidation rate of sphalerite, so that the presence of 13.94 wt.% Fe in sphalerite solid solution enhanced the rate of Zn extraction by a factor of 3.1.
For galena, lead chloride and elemental sulfur were the major phases causing surface passivation during leaching in ferric chloride and ferric perchlorate solutions, respectively. Passivation by lead chloride occurred during chloride leaching of galena immediately after the start of the reaction despite no solubility limitation of lead chloride; this was due to the local supersaturation of lead chloride in the vicinity of the particle, leading to significant passivation. On the contrary, no passivation occurred during ferric nitrate leaching, and the process was controlled by surface chemical reaction alone. Moving forward, response surface methodology (RSM) was employed to optimize the leaching of galena with hydrogen peroxide in acetate-based and citrate-based solutions. Galena leaching in citrate solutions showed promising results at pH 7 and 25°C. However, the formation of a thin lead-oxide layer caused passivation in the later stages of the process. To eliminate passivation, the size fraction needed to be chosen in the range of <38 µm. In acetate solutions, the formation of lead sulfate around the particle and alongside the cleavage plane significantly inhibited lead extraction.
For better investigating minerals leaching, a flow-through cell was developed for in situ synchrotron PXRD experiments at the Australian Synchrotron. The designed flow-through cell provides the opportunity to further investigate the mechanisms of minerals leaching in time-resolved conditions.
Overall, the outcomes of this thesis provide some scientific basis for developing greener approaches such as in situ leaching and heap leaching for recovering Zn and Pb from their sulfide ore minerals
Influencers: the importance of discussions with parents, teachers and friends to support vocational and university pathways
No full textEducational and career aspirations can be shaped by the expectations of significant others, including parents, teachers and peers. This study examined career discussions with significant others and how discussions about university or vocational education supported post-high school pathways. A mediation model examined the role of gender, year level, and first-in-family status to the links between pathway discussions and career expectations. The main findings suggested that students who discussed university more frequently with others were more likely to expect to attend university post high school. Students who discussed vocational and educational training pathways reported they were more likely to pursue vocational education. Students from low socioeconomic status backgrounds reported high expectations of attending vocational education and low expectations of attending university. Students discussed career and academic pathways with parents and peers more than with teachers and counsellors. This research informs influencers as to the importance of timely career pathway discussions