Nonlinear diffusion and exclusion processes with contact interactions

Exclusion processes on a regular lattice are used to model many biological and physical systems at a discrete level. The average properties of an exclusion process may be described by a continuum model given by a partial differential equation. We combine a general class of contact interactions with an exclusion process. We determine that many different types of contact interactions at the agent-level always give rise to a nonlinear diffusion equation, with a vast variety of diffusion functions D(C). We find that these functions may be dependent on the chosen lattice and the defined neighborhood of the contact interactions. Mild to moderate contact interaction strength generally results in good agreement between discrete and continuum models, while strong interactions often show discrepancies between the two, particularly when D(C) takes on negative values. We present a measure to predict the goodness of fit between the discrete and continuous model, and thus the validity of the continuum description of a motile, contact-interacting population of agents. This work has implications for modeling cell motility and interpreting cell motility assays, giving the ability to incorporate biologically realistic cell-cell interactions and develop global measures of discrete microscopic data.

Resorbable composite scaffolds for craniofacial bone tissue engineering

Aim: Bone loss associated with trauma, osteo-degenerative diseases and tumors has tremendous socioeconomic impact related to personal and occupation disability and health care costs. In the present climate of increasing life expectancy with an ensuing increase in bone-related injuries, orthopaedic surgery is undergoing a paradigm shift from bone-grafting to bone engineering, where a scaffold is implanted to provide adequate load bearing and enhance tissue regeneration. We aim to develop composite scaffolds for bone tissue engineering applications to replace the current gold standard of autografting. ---------- Methods: Medical grade polycaprolactone-tricalcium phosphate (mPCL/TCP) scaffolds (80/20 wt%) were custom made using fused deposition modelling to produce 1x1.5x2 cm sized implants for critical-sized pig cranial implantations, empty defects were used as a control. Autologous bone marrow stromal cells (BMSCs) were extracted and precultured for 2 weeks, dispersed within fibrin glue and injected during scaffold implantation. After 2 years, microcomputed tomography and histology were used to assess bone regenerative capabilities of cell versus cell-free scaffolds. ---------- Results: Extensive bone regeneration was evident throughout the entire scaffold. Clear osteocytes embedded within mineralised matrix and active osteoblasts present around scaffold struts were observed. Cell groups performed better than cell-free scaffolds. ---------- Conclusions: Bone regeneration within defects which cannot heal unassisted can be achieved using mPCL/TCP scaffolds. This is improved by the inclusion of autogenous BMSCs. Further work will include the inclusion of growth factors including BMP-2, VEGF and PDGF to provide multifunctional scaffolds, where the three-dimensional (3D) template itself acts as a biomimetic, programmable and multi-drug delivery device.

Resorbable composite scaffolds for bone tissue engineering

Bone loss associated with trauma osteo-degenerative diseases and tumors has tremendous socioeconomic impact related to personal and occupation disability and health care costs. Bone grafting is often critical to surgical therapies. Autogenous bone is presently the preferred grafting material; however, this holds several disadvantages such as donor site morbidity. In the present climate of increasing life expectancy with an ensuing increase in bone-related injuries, orthopaedic surgery is undergoing a paradigm shift from bone-grafting to bone engineering, where a scaffold is implanted to provide adequate load bearing and enhance tissue regeneration. Our group at Queensland University of Technology (QUT) have developed, characterised and tested polycaprolactone/ tricalcium phosphate (PCL/TCP) composite scaffolds for low load-bearing bone defects. These scaffolds are being further developed for application in higher load bearing sites. Our approach emphasizes the importance of the biomaterials’ structural design, the scaffold architecture and structural and nutritional requirements for cell culture. These first-generation scaffolds made from medical grade PCL (mPCL) have been studied for more than 5 years within a clinical setting 1. This paper describes the application of second-generation scaffolds in small and large animal bone defect models and the ensuing bone regeneration as shown by histology and µCT.

The role of organisational capacity in the knowledge-based transformation of Brisbane, Australia

Purpose - The cumulative impacts of the knowledge economy together with the emerging dominance of knowledge-intensive sectors, have led to an unprecedented period of socio-economic and spatial restructuring. As a result, the paradigm of knowledge-based urban development (KBUD) has emerged as a development strategy to guide knowledge-based economic transformation (Knight, 1995; Yigitcanlar, 2007). Notwithstanding widespread government commitment and financial investment, in many cases providing the enabling circumstances for KUBUD has proven a complicated task as institutional barriers remain. Researchers and practitioners advocate that the way organisations work and their institutional relationships, policies and programs, will have a significant impact on a regions capacity to achieve KBUD (Savitch, 1998; Savitch and Kantor, 2002; Keast and Mandell, 2009). In this context, building organisational capacity is critical to achieving institutional change and bring together all of the key actors and sources, for the successful development, adoption, and implementation of knowledge-based development of a city (Yigitcanlar, 2009). Design/methodology/approach - There is a growing need to determine the complex inter-institutional arrangements and intra-organisational interactions required to advance urban development within the knowledge economy. In order to design organisational capacity-building strategies, the associated attributes of good capacity must first be identified. The paper, with its appraisal of knowledge-based urban development, scrutinises organisational capacity and institutional change in Brisbane. As part of the discussion of the case study findings, the paper describes the institutional relationships, policies, programs and funding streams, which are supporting KBUD in the region. Originality/value - In consideration that there has been limited investigation into the institutional lineaments required to provide the enabling circumstances for KBUD, the broad aim of this paper is to discover some good organisational capacity attributes, achieved through a case study of Brisbane. Practical implications - It is anticipated that the findings of the case study will contribute to moving the discussion on the complex inter-institutional arrangements and intra-organisaational interactions required for KBUD, beyond a position of rhetoric.

Distributed creativity : filesharing and produsage

The culture of mashups which is examined by the contributions collected in this volume is a symptom of a wider paradigm shift in our engagement with information – a term which should be understood here in its broadest sense, ranging from factual material to creative works. It is a shift which has been a long time coming and has had many precedents, from the collage art of the Dadaists in the 1920s to the music mixtapes of the 70s and 80s, and finally to the explosion of mashup‐style practices that was enabled by modern computing technologies.

News produsage in a pro-am mediasphere : why citizen journalism matters

The rise to prominence of citizen journalism is usually described as a paradigm shift in the relationship between news organizations and their audiences – ‘citizen’ or ‘amateur’ journalists are positioned as inherently different from, and possibly in competition with, ‘professional’ journalists. Some journalists in the industry have taken up this theme, and are at pains to distinguish their professional, supposedly objective and accountable practices from what they describe as the opinionated and partisan ‘armchair journalism’ of amateurs, while some citizen journalists, in turn, give as good at they get and describe the professionals as lackeys of their corporate masters who (willingly or unwittingly) fall prey to political and commercial spin. In fact, the very terminology we use to describe both sides creates the impression that professionals are not also citizens, and that citizen journalists are incapable of having professional skills and knowledges; in reality, of course, the lines between them are much less clear.

The Guardian reportage of the UK MP expenses scandal: a case study of computational journalism

The Guardian reportage of the United Kingdom Member of Parliament (MP) expenses scandal of 2009 used crowdsourcing and computational journalism techniques. Computational journalism can be broadly defined as the application of computer science techniques to the activities of journalism. Its foundation lies in computer assisted reporting techniques and its importance is increasing due to the: (a) increasing availability of large scale government datasets for scrutiny; (b) declining cost, increasing power and ease of use of data mining and filtering software; and Web 2.0; and (c) explosion of online public engagement and opinion.. This paper provides a case study of the Guardian MP expenses scandal reportage and reveals some key challenges and opportunities for digital journalism. It finds journalists may increasingly take an active role in understanding, interpreting, verifying and reporting clues or conclusions that arise from the interrogations of datasets (computational journalism). Secondly a distinction should be made between information reportage and computational journalism in the digital realm, just as a distinction might be made between citizen reporting and citizen journalism. Thirdly, an opportunity exists for online news providers to take a ‘curatorial’ role, selecting and making easily available the best data sources for readers to use (information reportage). These activities have always been fundamental to journalism, however the way in which they are undertaken may change. Findings from this paper may suggest opportunities and challenges for the implementation of computational journalism techniques in practice by digital Australian media providers, and further areas of research.

Comparative communication research : Australian and New Zealand communication research in an international context

This paper raises the question of whether comparative national models of communications research can be developed, along the lines of Hallin and Mancini’s (2004) analysis of comparative media policy, or the work of Perraton and Clift (2004) on comparative national capitalisms. Taking consideration of communications research in Australia and New Zealand as its starting point, the paper will consider what are relevant variables in shaping an “intellectual milieu” for communications research in these countries, as compared to those of Europe, North America and Asia. Some possibly relevant variables include: • Type of media system (e.g. how significant is public service media?); • Political culture (e.g. are there significant left-of-centre political parties?); • Dominant intellectual traditions; • Level and types of research funding; • Overall structure of higher education system, and where communications sits within it. In considering whether such an exercise can or should be undertaken, we can also evaluate, as Hallin and Mancini do, the significance of potentially homogenizing forces. These would include globalization, new media technologies, and the rise of a global “audit culture”. The paper will raise these issues as questions that emerge as we consider, as Curran and Park (2000) and Thussu (2009) have proposed, what a “de-Westernized” media and communications research paradigm may look like.

Not yet the Internet election : online media, political commentary and the 2007 Australian federal election

This paper undertakes an overview of two developments in online media that coincided with the 'year-long campaign' that was the 2007 Australian Federal election. It discusses the relatively successful use of the Internet and social media in the 'Kevin07' Australian Labor Party campaign, and contrasts this to the Liberal-National Party's faltering use of You Tube for policy announcements. It also notes the struggle for authority in interpreting polling data between the mainstream media and various online commentators, and the 'July 12 incident' at The Australian, where it engaged in strong denunciation of alleged biases and prejudices among bloggers and on political Web sites. It concludes with consideration of some wider implication for political communication and the politics-media relationship, and whether we are seeing trends towards dispersal and diversification characterising the 'third age' of political communication.

Where money and meanings meet : theorizing the emergence of new values in media and education

Recent developments in technology, globalization, and consumer activism have challenged the "broadcasting model" of natonally bounded, vertically integrated, monopolistic, expert-paradigm media industries, dedicated to supplying leisure entertainment to more or less passive consumers. Instead, attention has turned to globally traded formats, social network markets, consumer-created content, multiplatform "publication," and a semiotic long tail where niche representations can be as valuable as blockbusters. Such chenges are just as much a challenge to education as they are to business models. And education, both formal and informal, is a dynamic agent in these processes, participation, and creative content require a rethink of "studies" just as much as of "media."

Solving navigational uncertainty using grid cells on robots

To successfully navigate their habitats, many mammals use a combination of two mechanisms, path integration and calibration using landmarks, which together enable them to estimate their location and orientation, or pose. In large natural environments, both these mechanisms are characterized by uncertainty: the path integration process is subject to the accumulation of error, while landmark calibration is limited by perceptual ambiguity. It remains unclear how animals form coherent spatial representations in the presence of such uncertainty. Navigation research using robots has determined that uncertainty can be effectively addressed by maintaining multiple probabilistic estimates of a robot's pose. Here we show how conjunctive grid cells in dorsocaudal medial entorhinal cortex (dMEC) may maintain multiple estimates of pose using a brain-based robot navigation system known as RatSLAM. Based both on rodent spatially-responsive cells and functional engineering principles, the cells at the core of the RatSLAM computational model have similar characteristics to rodent grid cells, which we demonstrate by replicating the seminal Moser experiments. We apply the RatSLAM model to a new experimental paradigm designed to examine the responses of a robot or animal in the presence of perceptual ambiguity. Our computational approach enables us to observe short-term population coding of multiple location hypotheses, a phenomenon which would not be easily observable in rodent recordings. We present behavioral and neural evidence demonstrating that the conjunctive grid cells maintain and propagate multiple estimates of pose, enabling the correct pose estimate to be resolved over time even without uniquely identifying cues. While recent research has focused on the grid-like firing characteristics, accuracy and representational capacity of grid cells, our results identify a possible critical and unique role for conjunctive grid cells in filtering sensory uncertainty. We anticipate our study to be a starting point for animal experiments that test navigation in perceptually ambiguous environments.

Availability of advance visual information constrains association-football goalkeeping performance during penalty kicks

A pressing concern within the literature on anticipatory perceptual-motor behaviour is the lack of clarity on the applicability of data, observed under video-simulation task constraints, to actual performance in which actions are coupled to perception, as captured during in-situ experimental conditions. We developed an in-situ experimental paradigm which manipulated the duration of anticipatory visual information from a penalty taker’s actions to examine experienced goalkeepers’ vulnerability to deception for the penalty kick in association football. Irrespective of the penalty taker’s kick strategy, goalkeepers initiated movement responses earlier across consecutively earlier presentation points. Overall goalkeeping performance was better in non-deception trials than in deception conditions. In deception trials, the kinematic information presented up until the penalty taker initiated his/her kicking action had a negative effect on goalkeepers’ performance. It is concluded that goalkeepers are likely to benefit from not anticipating a penalty taker’s performance outcome based on information from the run-up, in preference to later information that emerges just before the initiation of the penalty taker’s kicking action.

Reference bias : presentation of extreme health states prior to EQ-VAS improves health-related quality of life scores. A randomised crossover trial.

Background: Clinical practice and clinical research has made a concerted effort to move beyond the use of clinical indicators alone and embrace patient focused care through the use of patient reported outcomes such as healthrelated quality of life. However, unless patients give consistent consideration to the health states that give meaning to measurement scales used to evaluate these constructs, longitudinal comparison of these measures may be invalid. This study aimed to investigate whether patients give consideration to a standard health state rating scale (EQ-VAS) and whether consideration of good and poor health state descriptors immediately changes their selfreport. Methods: A randomised crossover trial was implemented amongst hospitalised older adults (n = 151). Patients were asked to consider descriptions of extremely good (Description-A) and poor (Description-B) health states. The EQ-VAS was administered as a self-report at baseline, after the first descriptors (A or B), then again after the remaining descriptors (B or A respectively). At baseline patients were also asked if they had considered either EQVAS anchors. Results: Overall 106/151 (70%) participants changed their self-evaluation by ≥5 points on the 100 point VAS, with a mean (SD) change of +4.5 (12) points (p < 0.001). A total of 74/151 (49%) participants did not consider the best health VAS anchor, of the 77 who did 59 (77%) thought the good health descriptors were more extreme (better) then they had previously considered. Similarly 85/151 (66%) participants did not consider the worst health anchor of the 66 who did 63 (95%) thought the poor health descriptors were more extreme (worse) then they had previously considered. Conclusions: Health state self-reports may not be well considered. An immediate significant shift in response can be elicited by exposure to a mere description of an extreme health state despite no actual change in underlying health state occurring. Caution should be exercised in research and clinical settings when interpreting subjective patient reported outcomes that are dependent on brief anchors for meaning. Trial Registration: Australian and New Zealand Clinical Trials Registry (#ACTRN12607000606482) http://www.anzctr. org.au

Developing a knowledge-based urban development analysis framework : the case of multimedia super corridor, Malaysia

Purpose: In the global knowledge economy, investment in knowledge-intensive industries and information and communication technology (ICT) infrastructures are seen as significant factors in improving the overall socio-economic fabric of cities. Consequently knowledge-based urban development (KBUD) has become a new paradigm in urban planning and development, for increasing the welfare and competitiveness of cities and regions. The paper discusses the critical connections between KBUD strategies and knowledge-intensive industries and ICT infrastructures. In particular, it investigates the application of the knowledge-based urban development concept by discussing one of South East Asia’s large scale manifestations of KBUD; Malaysia’s Multimedia Super Corridor. ----- ----- Design/methodology/approach: The paper provides a review of the KBUD concept and develops a knowledge-based urban development assessment framework to provide a clearer understanding of development and evolution of KBUD manifestations. Subsequently the paper investigates the implementation of the KBUD concept within the Malaysian context, and particularly the Multimedia Super Corridor (MSC). ----- ----- Originality/value: The paper, with its KBUD assessment framework, scrutinises Malaysia’s experince; providing an overview of the MSC project and discussion of the case findings. The development and evolution of the MSC is viewed with regard to KBUD policy implementation, infrastructural implications, and the agencies involved in the development and management of the MSC. ----- ----- Practical implications: The emergence of the knowledge economy, together with the issues of globalisation and rapid urbanisation, have created an urgent need for urban planners to explore new ways of strategising planning and development that encompasses the needs and requirements of the knowledge economy and society. In light of the literature and MSC case findings, the paper provides generic recommendations, on the orchestration of knowledge-based urban development, for other cities and regions seeking to transform to the knowledge economy.

Frank and Stein : from research scientist to creative writer (a screenplay and exegesis)

The screenplay, “Perfect Blood” (Frank and Stein), is the first two-hour episode of a two-part television miniseries Frank and Stein. This creative work is a science fiction story that speculates on the future of Western nations in a world where petroleum is scarce. A major theme that has been explored in the miniseries is the tension between the advantages and dangers of scientific progress without regard to human consequences. “Perfect Blood” (Frank and Stein) was written as part of my personal creative journey, which has been the transformation from research scientist to creative writer. In the exegetical component of this thesis, I propose that a key challenge for any scientist writing science fiction is the shift from conducting empirical research in a laboratory-based situation to engaging in creative practice research. During my personal creative journey, I found that a predominant difficulty in conducting research within a creative practice-led paradigm was unleashing my creativity and personal viewpoint, practices that are frowned upon in scientific research. The aim of the exegesis is to demonstrate that the transformative process from science to art is not neat and well-structured. My personal creative journey was fraught with many ‘wrong’ turns. However, after reflecting on the experience, I realise that every varied piece of research that I undertook allowed me to progress to the next stage, the next draft of Frank and Stein. And via the disorder of the creative process, a screenplay finally emerged that was both structured and creative, which are equally essential elements in screenwriting.