Mineralogy of chondritic interplanetary dust particles

From a mineralogical survey of approximately 30 chondritic micrometeorites collected from the lower stratosphere and studied in detail using current electron microscopy techniques, it is concluded that these particles represent a unique group of extraterrestrial materials. These micrometeorites differ significantly in form and texture from components of carbonaceous chondrites and contain some mineral assemblages which do not occur in any meteorite class. Electron microscope investigations of chondritic micrometeorites have established that these materials (1) are extraterrestrial in origin, (2) existed in space as small objects, (3) endured minimal alteration by planetary processes since formation, and (4) can suffer minimal pulse heating (<600°C) on entering earth's atmosphere. The probable sources for chondritic interplanetary dust particles (IDPs) are cometary and asteroidal debris and, perhaps to a lesser extent, interstellar regions. These sources have not been conclusively linked to any specific mineralogical subset of IDP, although the chondritic porous (CP) aggregate is considered of likely cometary origin. Chondritic IDPs occur in two predominant mineral assemblages: (1) carbonaceous phases and phyllosilicates and (2) carbonaceous phases and nesosilicates or inosilicates, although particles with both types of silicate assemblages are observed. Olivines, pyroxenes, layer silicates, and carbon-rich phases are the most commonly occurring minerals in many chondritic IDPs. Other phases often observed in variable proportions include sulphides, spinels, metals, metal carbides, carbonates, and minor amounts of sulphates and phosphates. Individual mineral grain sizes range from micrometers (primarily pyroxenes and olivines) to nanometers, with the predominant size for all phases less than 100 nm. Specific mineral characteristics for particular chondritic IDPs provide an indication of processes which may have occurred prior to collection in the earth's stratosphere. For example, pyroxene mineralogy in some chondritic aggregates is consistent with condensation from a vapor phase and, we consider, with condensation in a turbulent solar nebula at relatively low temperatures (<1000°C). Carbonaceous phases present in other CP aggregates have been used to imply low-temperature formation processes such as Fischer-Tropsch synthesis (∼530°C) or carbonization and graphitization (∼315°C). Alteration processes have been implicated in the formation of some layer silicates in CP aggregates and may have involved hydrocryogenic alteration at <0°C. In general, interpretations of transformation processes on submicrometer-size minerals in chondritic IDPs are consistent with formation at a radius equivalent to the asteroid belt or greater during the later stages of solar nebula evolution using currently available models.

Grain size distributions of Magneli phases and metallic titanium in chondritic porous interplanetary dust particles

A mineralogical survey of chondritic interplanetary dust particles (IDPs)showed that these micrometeorites differ significantly in form and texture from components of carbonaceous chondrites and contain some mineral assemblages which do not occur in any meteorite class1. Models of chondritic IDP mineral evolution generally ignore the typical (ultra-) fine grain size of consituent minerals which range between 0.002-0.1µm in size2. The chondritic porous (CP) subset of chondritic IDPs is probably debris from short period comets although evidence for a cometary origin is still circumstantial3. If CP IDPs represent dust from regions of the Solar System in which comet accretion occurred, it can be argued that pervasive mineralogical evolution of IDP dust has been arrested due to cryogenic storage in comet nuclei. Thus, preservation in CP IDPs of "unusual meteorite minerals", such as oxides of tin, bismuth and titanium4, should not be dismissed casually. These minerals may contain specific information about processes that occurred in regions of the solar nebula, and early Solar System, which spawned the IDP parent bodies such as comets and C, P and D asteroids6. It is not fully appreciated that the apparent disparity between the mineralogy of CP IDPs and carbonaceous chondrite matrix may also be caused by the choice of electron-beam techniques with different analytical resolution. For example, Mg-Si-Fe distributions of Cl matrix obtained by "defocussed beam" microprobe analyses are displaced towards lower Fe-values when using analytical electron microscope (AEM)data which resolve individual mineral grains of various layer silicates and magnetite in the same matrix6,7. In general, "unusual meteorite minerals" in chondritic IDPs, such as metallic titanium, Tin01-n(Magneli phases) and anatase8 add to the mineral data base of fine-grained Solar System materials and provide constraints on processes that occurred in the early Solar System.

Facebook, Twitter, SMS and YouTube : the ramifications and risks for surgeons

Social media revolution has impacted on how people interact with one another. This has been a worldwide phenomenon. Whilst social media had its genesis in the personal and private realm its use has expanded exponentially to professional and business contexts, as well as being adopted by governments, politicians, journalists – everyone in just about every walk of life. Although at first the uptake was slow, surgeons and other health professionals are now using social media in their professional as well as personal capacity. This comes with significant advantages and opportunities for improving surgical practice and for facilitating attending communication, but it also comes with certain risks, including legal liability. This paper outlines the ways in which social media including, Facebook, Twitter, YouTube and SMS, is increasingly being employed in surgical practice and explains the legal and ethical consequences that may inadvertently arise in its official, as well as, unofficial use.

Governance of learning mechanisms : evidence from construction firms

The focus of knowledge management (KM) in the construction industry is moving towards capability building for value creation. The study reported by this paper is motivated by recent assertions about the genesis and evolution of knowledge management capability (KMC) in the strategic management field. It attempts to shed light on the governance of learning mechanisms that develop KMC within the context of construction firms. A questionnaire survey was administered to a sample of construction contractors operating in the very dynamic Hong Kong market to elicit opinions on the learning mechanisms and business outcomes of targeted firms. On the basis of a total of 149 usable responses, structural equation modeling (SEM) analysis identified relationships among knowledge-governance mechanisms, knowledge processes, and business performance, thereby supporting the existence of strategic learning loops. The study findings provide evidence from the construction context for capability assertions that knowledge-governance mechanisms and processes form learning mechanisms that carry out strategic learning to create value, effect performance outcomes, and ultimately drive the evolution of KMC. The findings imply that it is feasible for managing construction firms to govern learning mechanisms through managing the capability-based holistic KM system, thereby reconfiguring KMC to match needs in the dynamic market environment over time.

Visualizing the evolution of knowledge management capability in construction firms

A firm, as a dynamic, evolving, and quasi-autonomous system of knowledge production and application, develops knowledge management capability (KMC) through strategic learning in order to sustain competitive advantages in a dynamic environment. Knowledge governance mechanisms and knowledge processes connect and interact with each other forming learning mechanisms, which carry out double loop learning that drives genesis and evolution of KMC to modify operating routines that effect desired performance. This paper reports a study that was carried out within a context of construction contractors, a type of project-based firms, operating within the dynamic Hong Kong construction market. A multiple-case design was used to incorporate evidence from the literature and interviews, with the help of system dynamics modeling, to visualize the evolution of KMC. The study demonstrates the feasibility to visualize how a firm's KMC matches its operating environment over time. The findings imply that knowledge management (KM) applications can be better planned and controlled through evaluation of KM performance over time from a capability perspective.

A new database compilation of whole-rock chemical and geochronological data of igneous rocks in Queensland : a new resource for HDR geothermal resource exploration

The Geothermal industry in Australia and Queensland is in its infancy and for hot dry rock (HDR) geothermal energy, it is very much in the target identification and resource definition stages. As a key effort to assist the geothermal industry and exploration for HDR in Queensland, we are developing a comprehensive and new integrated geochemical and geochronological database on igneous rocks. To date, around 18,000 igneous rocks have been analysed across Queensland for chemical and/or age information. However, these data currently reside in a number of disparate datasets (e.g., Ozchron, Champion et al., 2007, Geological Survey of Queensland, journal publications, and unpublished university theses). The goal of this project is to collate and integrate these data on Queensland igneous rocks to improve our understanding of high heat producing granites in Queensland, in terms of their distribution (particularly in the subsurface), dimensions, ages, and controlling factors in their genesis.

25 million years to break a continent : early to middle Miocene rifting and syn-extensional magmatism in the southern Gulf of California

Cenozoic extension in western Mexico has been divided into two episodes separated by the change from convergence to oblique divergence at the plate boundary. The Gulf Extensional Province is thought to have started once subduction ended at ~12.5 Ma whereas early extension is classified as Basin and Range. Mid-Miocene volcanism of the Comondú group has been considered as a subduction-related arc, whereas post ~12.5 Ma volcanism would be extension-related. Our new integration of the continental onshore and offshore geology of the south-east Gulf region, backed by tens of Ar-Ar and U-Pb ages and geochemical studies, document an early-mid Miocene rifting and extension-related bimodal to andesitic magmatism prior to subduction termination. Between ~21 and 11 Ma a system of NNW-SSE high-angle extensional faults rifted the western side of the Sierra Madre Occidental (SMO) ignimbrite plateau. In Nayarit, rhyolitic domes and some basalts were emplaced along this extensional belt at 18-17 Ma. These rocks show strong antecrystic inheritance but an absence of Mesozoic and older xenocrysts, suggesting a genesis in the mid-upper crust triggered by extension-induced basaltic influx. In Sinaloa, large grabens were floored by huge dome complexes at ~21-17 Ma and filled by continental sediments with interlayered basalts dated at 15 Ma. Mid-Miocene volcanism, including the largely volcaniclastic Comondú strata in Baja California, was thus emplaced in rift basins and appears associated to decompression melting rather than subduction. Along the coast, flat-lying basaltic lava flows dated at 11-10 Ma are exposed just above the present sea level. Here crustal thickness is 25-20 Km, almost half that in the core of the SMO, implying significant lithosphere stretching before ~11 Ma. This mafic pulse, with relatively high Ti but still clear Nb-Ta negative spikes, may be related to the detachment of the lower part of the subducted slab, allowing asthenosphere to flow into parts of the mantle previously fluxed by subduction fluids. Very uniform OIB-like lavas appear in late Pliocene and Pleistocene, only 18 m.y. after the onset of rifting and ~9 m.y. after the end of subduction. Our study shows that rifting began much earlier than Late Miocene and progressively overwhelmed subduction in generating magmatism.

Teaching teachers for the future : how, what, why, and what next?

This paper contextualises the Teaching Teachers of the Future (TTF) Project and acts as a preamble for the TTF stream of papers at ACEC2012. It discusses the aims and objectives of the project, its genesis in a changing educational and political landscape, the use of TPACK as a theoretical scaffold, and briefly report on the operations of the various components and partners. Further, it will discuss the research opportunities afforded by the project including a national survey of all pre-service teachers in Australia gauging their TPACK confidence and the use of the Most Significant Change (MSC) methodology. Finally the paper will discuss the outcomes of the project and its future.

Approaches to creativity : how adolescents engage in the creative process

Despite growing recognition of creativity's importance for young people, the creativity of adolescents remains a neglected field of study. Hence, grounded theory research was conducted with 20 adolescents from two Australian schools regarding their self-reported experiences of creativity in diverse domains. Four approaches to the creative process – adaptation, transfer, synthesis, and genesis – emerged from the research. These approaches used by students across a range of domains contribute to the literature in two key ways: (a) explaining how adolescents engage in the creative process, theorised from adolescent creators’ self-reports of their experiences and (b) confirms hybrid theories that recognise that creativity has elements of both domain-generality and domain-specificity. The findings have educational implications for both students and teachers. For students, enhancing metacognitive awareness of their preferred approaches to creativity was reported as a valuable experience in itself, and might also enable adolescents to expand their creativity through experimenting with other ways of engaging in the creative process. For teachers, using these understandings to underpin their pedagogies can promote metacognitive awareness and experimentation, and also provide teachers with a framework for assessing students’ creative processes.

Beyond the accolades : a postcolonial critique of the foundations of the Ottawa Charter

Introduction: The Ottawa Charter is undeniably of pivotal importance in the history of ideas associated with the establishment of health promotion. There is much to applaud in a charter which responds to the need to take action on the social and economic determinants of health and which seeks to empower communities to be at the centre of this. Such accolades tend to position the Ottawa Charter as ‘beyond critique’; a taken-for-granted ‘given’ in the history of health promotion. In contrast, we argue it is imperative to critically reflect on its ‘manufacture’ and assess the possibility that certain voices have been privileged, and others marginalized. Methods: This paper re-examines the 1986 Ottawa Conference including its background papers from a postcolonial standpoint. We use critical discourse analysis as a tool to identify the enactment of power within the production of the Ottawa health promotion discourse. This exercise draws attention to both the power to ensure the dominant presence of privileged voices at the conference as well as the discursive strategies deployed to ‘naturalize’ the social order of inequality. Results: Our analysis shows that the discourse informing the development of the Ottawa Charter strongly reflected Western/colonizer centric worldviews, and actively silenced the possibility of countervailing Indigenous and developing country voices. Conclusion: The Ottawa Charter espouses principles of participation, empowerment and social justice. We question then whether the genesis of the Ottawa Charter lives up to its own principles of practice. We conclude that reflexive practice is crucial to health promotion, which ought to include a preparedness for health promotion to more critically acknowledge its own history.

Beyond the accolades : a postcolonial critique of the foundations of the Ottawa Charter

This presentation provides an overview of our work recently published paper in Global Health Promotion, which re-examined the production of the Ottawa Charter for Health Promotion. In the presentation, I provide an overview of the way we used critical discourse analysis from a postcolonial standpoint. Our analysis shows that the discourse informing the development of the Ottawa Charter strongly reflected Western/colonizer centric worldviews, and actively silenced the possibility of countervailing Indigenous and developing country voices. We question whether the genesis of the Ottawa Charter lives up to its own principles of practice. We conclude that reflexive practice is crucial to health promotion, which ought to include a preparedness for health promotion to more critically acknowledge its own history.

Iron nodules in ferric soils of the Fraser Coast, Australia : relicts of laterisation or features of contemporary weathering and pedogenesis?

The genesis of ferruginous nodules and pisoliths in soils and weathering profiles of coastal southern and eastern Australia has long been debated. It is not clear whether iron (Fe) nodules are redox accumulations, residues of Miocene laterite duricrust, or the products of contemporary weathering of Fe-rich sedimentary rocks. This study combines a catchment-wide survey of Fe nodule distribution in Poona Creek catchment (Fraser Coast, Queensland) with detailed investigations of a representative ferric soil profile to show that Fe nodules are derived from Fe-rich sandstones. Where these crop out, they are broken down, transported downslope by colluvial processes, and redeposited. Chemical and physical weathering transforms these eroded rock fragments into non-magnetic Fe nodules. Major features of this transformation include lower hematite/goethite and kaolinite/gibbsite ratios, increased porosity, etching of quartz grains, and development of rounded morphology and a smooth outer cortex. Iron nodules are commonly concentrated in ferric horizons. We show that these horizons form as the result of differential biological mixing of the soil. Bioturbation gradually buries nodules and rock fragments deposited at the surface of the soil, resulting in a largely nodule-free 'biomantle' over a ferric 'stone line'. Maghemite-rich magnetic nodules are a prominent feature of the upper half of the profile. These are most likely formed by the thermal alteration of non-magnetic nodules located at the top of the profile during severe bushfires. They are subsequently redistributed through the soil profile by bioturbation. Iron nodules occurring in the study area are products of contemporary weathering of Fe-rich rock units. They are not laterite duricrust residues nor are they redox accumulations, although redox-controlled dissolution/re-precipitation is an important component of post-depositional modification of these Fe nodules.

Echo theatre : from experience to performance

This research project investigates the characteristics of Echo Theatre, its potential to foster performative and narrative competencies in students, and the role of the teacher in this performative and educational practice. Echo Theatre is a method devised during my storytelling practice and this research confirms that there is no identical research or teaching practice which involves students staging personal narratives in the classroom in this way. The study has been informed by crossdisciplinary theory studies from the fields of phenomenology, cognitive sciences, and theatre practice. To analyse and discuss Echo Theatre's potential contribution to the development of the child I have defined the concept of a performative competence as well as redefined the concept of a narrative competence. The situated, embodied and performative character of human cognition is emphasised as physical actions and thinking in movement is related to both gestural and conceptual understandings. Studies in philosophy and psychology confirm that narrative structure, related to identity construction and meaning-­‐making, can be attained through the performing body. We tell stories to know who we are. Telling stories then in the Echo Theatre model develops multiple competencies related to the performative aspects of theatre practice as well as the narrative aspects of storytelling. The practice-­‐led aspect of this research project includes two fieldwork projects involving a primary school class who created sixteen different Echo Theatre stories. Student participation reveals that Echo Theatre is most constructive when it moves through five phases; recalled experience, narrative, drama, performance, and evaluation. Ongoing reflection is a part of all five phases. The study also confirms that while there is potential for Echo Theatre to support the development of performative and narrative competencies in students, the effectiveness of this directly relates to the teacher's theatre knowledge and skills and his or her didactic attitude towards the students. This study confirms that the potential for learning through the moving and performing body of Echo Theatre is strengthened by working with personal narratives in the classroom and led by teachers displaying heightened skills and knowledge of the aesthetics and dynamics of theatrical form.

Theatre-arts pedagogy for social justice : case study of the area youth foundation in Jamaica

In this paper I describe and analyse the socio-educational significance of a theatre arts approach to learning for young adults in Jamaica, implemented by the Area Youth Foundation (AYF). Briefly outlining the genesis and development of the AYF, I provide snapshots of the experiences and destinations of some of its young participants. The paper discusses AYF workshops to show how the pedagogy was shaped by the expressive arts and based on the critical praxis approach systematized by Paulo Freire in adult education and Augusto Boal in theatre. Based on interviews with AYF’s leader and some of the learners, I discuss how the foundation’s motto, “Youth Empowerment Through the Arts,” is played out in workshops and creative productions that are simultaneously learner-driven and teacher-guided, with the powerful impact of inspiring politically thoughtful creativity and skills in youths from less-privileged communities.

Teaching teachers for the future : how, what, why, and what next?

This paper contextualises the Teaching Teachers of the Future (TTF) Project and acts as a preamble for the TTF stream of papers at ACEC2012. It discusses the aims and objectives of the project, its genesis in a changing educational and political landscape, the use of TPACK as a theoretical scaffold, and briefly report on the operations of the various components and partners. Further, it will discuss the research opportunities afforded by the project including a national survey of all pre-service teachers in Australia gauging their TPACK confidence and the use of the Most Significant Change (MSC) methodology. Finally the paper will discuss the outcomes of the project and its future.