Negotiating community and knowledge in asynchronous online discussions in higher education

University of Technology Sydney. Faculty of Arts and Social Sciences.This thesis examines the enactment of teaching and learning in asynchronous online discussions in a postgraduate context. Specifically, it explores and seeks to explain the disjunct between the pedagogical promise of such discussions, founded on the collaborative construction of knowledge within supportive and democratised online communities, and the experience of teaching and learning through them, reported both in the research context and in published research. This experience often includes concern that students are failing to reach higher levels of knowledge construction, uncertainty on the part of moderators concerning their role and feelings of discomfort, disengagement and inadequate interaction on the part of students. The aim of the study is to provide a detailed account of this new and still evolving genre, rendering it transparent and able to be modelled and scaffolded pedagogically. The data for the study are the online discussion posts as captured by the learning management system, supplemented by survey responses. The approach taken is discourse analytical, informed by a social theory of language, namely Systemic Functional Linguistics (SFL). The core of the analysis is a detailed study of the discourse semantics of interpersonal meaning drawing on the system of APPRAISAL (Martin & White 2005), with some reference to INVOLVEMENT and NEGOTIATION. The negotiation of interpersonal meaning, studied within the context of community formation and maintenance, is profoundly influenced by mode features (written but dialogic, public, visible, persistent). Moderators’ linguistic choices commonly include incongruent instructions, reduced commitment of meaning, implicit feedback and a tendency to expand rather than contract space for other voices and meanings. This serves to reduce status differentials and support a sense of community but potentially impacts on the negotiation of ideational meaning. Similarly low-key was students’ relationship to the knowledge they brought into the discussion, particularly seen in the absence of standard forms of engagement in favour of narrative approaches and a tendency to open discursive space for others. Interaction with peers was likewise low-key for the most part, with little challenge and argumentation. Interestingly, students showed an individualistic concern with their own actions and postings, foregrounding their mental processes and personalising their approach to knowledge. Again attention to interpersonal relations appears to undermine to a certain extent ideational meaning-making. Addressing structural questions, a curriculum macrogenre was proposed and the presence of whole or fragmented written academic genres embedded in a quasi-conversational matrix identified. The pedagogical implications of these findings are discussed

Tales Bent Backward: Early Modern Local History in Persianate Transregional Contexts

AbstractThis article contributes to a growing body of scholarship on immigrants from Safavid Iran who travelled back and forth between their home cities and Hind during the early modern period. Intending to better comprehend some of the key mentalities and social practices of these cosmopolitan Persianate communities, I explore the literary strategies by which migrants worked to negotiate their place in rapidly transforming and highly competitive political environments in both Hind and Iran. Focusing on migration narratives that were commonly embedded in Persian historical works, I examine a cluster of local and dynastic histories that were composed in dialogue with one another and that emerged around a particular corridor of migration linking the Iranian city of Yazd with various cities in the Deccan. Previous scholarship has argued that immigrants could acquire social capital in their new environments by commemorating ties to Iranian cities through narratives of migration. I demonstrate that migrants also brought migration stories they had found in the Deccan back to their hometowns in Iran, where they redeployed them for similar political ends in new works of history.</jats:p

An Efficient Algorithm For Chinese Postman Walk on Bi-directed de Bruijn Graphs

Sequence assembly from short reads is an important problem in biology. It is known that solving the sequence assembly problem exactly on a bi-directed de Bruijn graph or a string graph is intractable. However finding a Shortest Double stranded DNA string (SDDNA) containing all the k-long words in the reads seems to be a good heuristic to get close to the original genome. This problem is equivalent to finding a cyclic Chinese Postman (CP) walk on the underlying un-weighted bi-directed de Bruijn graph built from the reads. The Chinese Postman walk Problem (CPP) is solved by reducing it to a general bi-directed flow on this graph which runs in O(|E|2 log2(|V |)) time. In this paper we show that the cyclic CPP on bi-directed graphs can be solved without reducing it to bi-directed flow. We present a ?(p(|V | + |E|) log(|V |) + (dmaxp)3) time algorithm to solve the cyclic CPP on a weighted bi-directed de Bruijn graph, where p = max{|{v|din(v) - dout(v) > 0}|, |{v|din(v) - dout(v) < 0}|} and dmax = max{|din(v) - dout(v)}. Our algorithm performs asymptotically better than the bidirected flow algorithm when the number of imbalanced nodes p is much less than the nodes in the bi-directed graph. From our experimental results on various datasets, we have noticed that the value of p/|V | lies between 0.08% and 0.13% with 95% probability

Noninvasive Measurement of Dissipation in Colloidal Systems

According to Harada and Sasa [Phys. Rev. Lett. 95, 130602 (2005)], heat production generated in a non-equilibrium steady state can be inferred from measuring response and correlation functions. In many colloidal systems, however, it is a nontrivial task to determine response functions, whereas details about spatial steady state trajectories are easily accessible. Using a simple conditional averaging procedure, we show how this fact can be exploited to reliably evaluate average heat production. We test this method using Brownian dynamics simulations, and apply it to experimental data of an interacting driven colloidal system

Interaction between U/UO2 bilayers and hydrogen studied by in-situ X-ray diffraction

This paper reports experiments investigating the reaction of H$_{2}$ with uranium metal-oxide bilayers. The bilayers consist of $\leq$ 100 nm of epitaxial $\alpha$-U (grown on a Nb buffer deposited on sapphire) with a UO$_{2}$ overlayer of thicknesses of between 20 and 80 nm. The oxides were made either by depositing via reactive magnetron sputtering, or allowing the uranium metal to oxidise in air at room temperature. The bilayers were exposed to hydrogen, with sample temperatures between 80 and 200 C, and monitored via in-situ x-ray diffraction and complimentary experiments conducted using Scanning Transmission Electron Microscopy - Electron Energy Loss Spectroscopy (STEM-EELS). Small partial pressures of H$_{2}$ caused rapid consumption of the U metal and lead to changes in the intensity and position of the diffraction peaks from both the UO$_{2}$ overlayers and the U metal. There is an orientational dependence in the rate of U consumption. From changes in the lattice parameter we deduce that hydrogen enters both the oxide and metal layers, contracting the oxide and expanding the metal. The air-grown oxide overlayers appear to hinder the H$_{2}$-reaction up to a threshold dose, but then on heating from 80 to 140 C the consumption is more rapid than for the as-deposited overlayers. STEM-EELS establishes that the U-hydride layer lies at the oxide-metal interface, and that the initial formation is at defects or grain boundaries, and involves the formation of amorphous and/or nanocrystalline UH$_{3}$. This explains why no diffraction peaks from UH$_{3}$ are observed. {\textcopyright British Crown Owned Copyright 2017/AWE}Comment: Submitted for peer revie

Temperature-dependent Hall scattering factor and drift mobility in remotely doped Si:B/SiGe/Si heterostructures

Hall-and-Strip measurements on modulation-doped SiGe heterostructures and combined Hall and capacitance–voltage measurements on metal-oxide-semiconductor (MOS)-gated enhancement mode structures have been used to deduce Hall scattering factors, rH, in the Si1 – xGex two-dimensional hole gas. At 300 K, rH was found to be equal to 0.4 for x = 0.2 and x = 0.3. Knowing rH, it is possible to calculate the 300 K drift mobilities in the modulation-doped structures which are found to be 400 cm2 V – 1 s – 1 at a carrier density of 3.3 × 1011 cm – 2 for x = 0.2 and 300 cm2 V – 1 s – 1 at 6.3 × 1011 cm – 2 for x = 0.3, factors of between 1.5 and 2.0 greater than a Si pMOS control

Unexpected phase locking of magnetic fluctuations in the multi-k magnet USb

The spin waves in the multi-k antiferromagnet USb soften and become quasielastic well below the antiferromagnetic ordering temperature TN. This occurs without a magnetic or structural transition. It has been suggested that this change is in fact due to dephasing of the different multi-k components: a switch from 3-k to 1-k behavior. In this work, we use inelastic neutron scattering with tridirectional polarization analysis to probe the quasielastic magnetic excitations and reveal that the 3-k structure does not dephase. More surprisingly, the paramagnetic correlations also maintain the same clear phase correlations well above TN (up to at least 1.4TN)