Optimal eradication: When to stop looking for an invasive plant

The notion of being sure that you have completely eradicated an invasive species is fanciful because of imperfect detection and persistent seed banks. Eradication is commonly declared either on an ad hoc basis, on notions of seed bank longevity, or on setting arbitrary thresholds of 1% or 5% confidence that the species is not present. Rather than declaring eradication at some arbitrary level of confidence, we take an economic approach in which we stop looking when the expected costs outweigh the expected benefits. We develop theory that determines the number of years of absent surveys required to minimize the net expected cost. Given detection of a species is imperfect, the optimal stopping time is a trade-off between the cost of continued surveying and the cost of escape and damage if eradication is declared too soon. A simple rule of thumb compares well to the exact optimal solution using stochastic dynamic programming. Application of the approach to the eradication programme of Helenium amarum reveals that the actual stopping time was a precautionary one given the ranges for each parameter. © 2006 Blackwell Publishing Ltd/CNRS.

Mobile phone use in Australian Indigenous communities : future pathways for HC14D

This paper collates recent research on mobile phone use in Indigenous communities in Australia. Its key finding is that mobile phones are heavily used in these communities, albeit in unique and unusual ways that may be difficult to comprehend beneath 'top-down' measurements. Rather than framing these uses as being compromises made in lieu of appropriate infrastructures or literacies, it is argued that HCI4D (Human-Computer Interaction for Development) would be better served by seriously plumbing into the information they reveal about how mobile phones are constructed and placed in these communities, and what these factors might reveal about local understandings of development and well-being. A consideration of these specific patterns of appropriation is necessary to push the field beyond top-down, rationalist approaches to development towards more flexible, creative solutions that build from local knowledge and competencies.

Numerical investigation of plant tissue porosity and its influence on cellular level shrinkage during drying

Dried plant food products are increasing in demand in the consumer market, leading to continuing research to develop better products and processing techniques. Plant materials are porous structures, which undergo large deformations during drying. For any given food material, porosity and other cellular parameters have a direct influence on the level of shrinkage and deformation characteristics during drying, which involve complex mechanisms. In order to better understand such mechanisms and their interrelationships, numerical modelling can be used as a tool. In contrast to conventional grid-based modelling techniques, it is considered that meshfree methods may have a higher potential for modelling large deformations of multiphase problem domains. This work uses a meshfree based microscale plant tissue drying model, which was recently developed by the authors. Here, the effects of porosity have been newly accounted for in the model with the objective of studying porosity development during drying and its influence on shrinkage at the cellular level. For simplicity, only open pores are modelled and in order to investigate the influence of different cellular parameters, both apple and grape tissues were used in the study. The simulation results indicated that the porosity negatively influences shrinkage during drying and the porosity decreases as the moisture content reduces (when open pores are considered). Also, there is a clear difference in the deformations of cells, tissues and pores, which is mainly influenced by the cell wall contraction effects during drying.

Improving access to housing for low-income communities in Dhaka: From rhetoric to reality in community participation

The research explores how community participation can address affordable housing problems of the poor in Dhaka. The research, based on extensive interviews, community focus groups and household surveys in different Dhaka slums, identifies the limiting factors to promote community participation in affordable housing creation. In Dhaka housing options for poor are currently limited to affordable shelters in informal settlements. Public housing programs have failed to reach the poor and meet affordability levels due to a number of factors including lack of beneficiary participation. Beneficiary participation, though widely recognized for success in housing initiatives, often deteriorates in process of implementation into mere involvement, not reflecting community needs and aspirations and thus failing to meet its core objectives. This research identified the most significant impediments as well as opportunities to advance participation in their own housing provisions in Dhaka city.

Literacy, place, and pedagogies of possibility: Working against residualization effects and deficit discourses in poor school communities

Australia has a long history of policy attention to the education of poor and working-class youth (Connell, 1994), yet currently on standardized educational outcomes measures the gaps are widening in ways that relate to social background, including race, location and class. An economic analysis of school choice in Australia reveals that a high proportion of government school students now come from lower Socio-Economic Status (SES) backgrounds (Ryan & Watson, 2004), indicating a trend towards a gradual residualisation of the poor in government schools, with increased private school enrolments as a confirmed national trend. The spatial distribution of poverty and the effects on school populations are not unique to Australia (Lupton, 2003; Lipman, 2011; Ryan, 2010). Raffo and colleagues (2010) recently provided a synthesis of socially critical approaches towards schooling and poverty arguing that what is needed are shifts in the balances of power to reposition those within the educational system as having some say in the ways schooling is organized. ‘Disadvantaged’ primary schools are not a marginal concern for education systems, but now account for a large and growing number of schools that serve an ever increasing population being made redundant, in part-time precarious work, under-employed or unemployed (Thomson 2002; Smyth, Down et al 2010). In Australia, the notion of the ‘disadvantaged’ school now refers to those, mostly public schools, being residualised by a politics of parental choice that drives neoliberalising policy logic (Bonner & Caro 2007; Hattam & Comber, forthcoming 2014; Thomson & Reid, 2003)...

Numerical investigation of case hardening of plant tissue during dying and its influence on the cellular level shrinkage

Dried plant food materials are one of the major contributors to the global food industry. Widening the fundamental understanding on different mechanisms of food material alterations during drying assists the development of novel dried food products and processing techniques. In this regard, case hardening is an important phenomenon, commonly observed during the drying processes of plant food materials, which significantly influences the product quality and process performance. In this work, a recent meshfree-based numerical model of the authors is further improved and used to simulate the influence of case hardening on shrinkage characteristics of plant tissues during drying. In order to model fluid and wall mechanisms in each cell, Smoothed Particle Hydrodynamics (SPH) and the Discrete Element Method (DEM) are used. The model is fundamentally more capable of simulating large deformation of multiphase materials, when compared with conventional grid-based modelling techniques such as Finite Element Methods (FEM) or Finite Difference Methods (FDM). Case hardening is implemented by maintaining distinct moisture levels in the different cell layers of a given tissue. In order to compare and investigate different factors influencing tissue deformations under case hardening, four different plant tissue varieties (apple, potato, carrot and grape) are studied. The simulation results indicate that the inner cells of any given tissue undergo limited shrinkage and cell wall wrinkling compared to the case hardened outer cell layers of the tissues. When comparing unique deformation characteristics of the different tissues, irrespective of the normalised moisture content, the cell size, cell fluid turgor pressure and cell wall characteristics influence the tissue response to case hardening.

The Arab Spring on Twitter: Language Communities in #egypt and #libya

Building on hashtag datasets gathered since January 2011, this paper will compare patterns of Twitter usage during the popular revolution in Egypt and the civil war in Libya. Using custom-made tools for processing ‘big data’ (boyd & Crawford, 2011), we will examine the volume of tweets sent by English-, Arabic-, and mixed-language Twitter users over time, and examine the networks of interaction (variously through @replying, retweeting, or both) between these groups as they developed and shifted over the course of these uprisings. Examining @reply and retweet traffic, we will identify general patterns of information flow between the English- and Arabic-speaking sides of the Twittersphere, and highlight the roles played by key boundary riders connecting both language spheres. Further, we will examine the URLs shared in these hashtags by Twitter participants, to identify the most prominent overall information sources, examine differences in the information diet experienced by English- and Arabic-language users, and investigate whether there are any online sources whose URLs are transcending language boundaries more frequently than others.

The combination of plant-expressed cellobiohydrolase and low dosages of cellulases for the hydrolysis of sugar cane bagasse

Background The expression of biomass-degrading enzymes (such as cellobiohydrolases) in transgenic plants has the potential to reduce the costs of biomass saccharification by providing a source of enzymes to supplement commercial cellulase mixtures. Cellobiohydrolases are the main enzymes in commercial cellulase mixtures. In the present study, a cellobiohydrolase was expressed in transgenic corn stover leaf and assessed as an additive for two commercial cellulase mixtures for the saccharification of pretreated sugar cane bagasse obtained by different processes. Results Recombinant cellobiohydrolase in the senescent leaves of transgenic corn was extracted using a simple buffer with no concentration step. The extract significantly enhanced the performance of Celluclast 1.5 L (a commercial cellulase mixture) by up to fourfold on sugar cane bagasse pretreated at the pilot scale using a dilute sulfuric acid steam explosion process compared to the commercial cellulase mixture on its own. Also, the extracts were able to enhance the performance of Cellic CTec2 (a commercial cellulase mixture) up to fourfold on a range of residues from sugar cane bagasse pretreated at the laboratory (using acidified ethylene carbonate/ethylene glycol, 1-butyl-3-methylimidazolium chloride, and ball-milling) and pilot (dilute sodium hydroxide and glycerol/hydrochloric acid steam explosion) scales. We have demonstrated using tap water as a solvent (under conditions that mimic an industrial process) extraction of about 90% recombinant cellobiohydrolase from senescent, transgenic corn stover leaf that had minimal tissue disruption. Conclusions The accumulation of recombinant cellobiohydrolase in senescent, transgenic corn stover leaf is a viable strategy to reduce the saccharification cost associated with the production of fermentable sugars from pretreated biomass. We envisage an industrial-scale process in which transgenic plants provide both fibre and biomass-degrading enzymes for pretreatment and enzymatic hydrolysis, respectively.

Playing Pranks: Traditions, communities & co-creative cultural performance practice

Pranks, hoaxes and practical jokes are co-creative cultural performance practices that appear across times, contexts and cultures. These practices include everyday play amongst families, friends and coworkers, entertainment programs such as Prank Patrol, Punked or Scare Tactics, and aesthetic and activist pranks perpetrated by situationist artists, guerrilla artists, and, most recently, culture ‘jammers’ or ‘hackers’ intent on turning capitalist systems back on themselves. Although it can, in common usage, describe almost any show off behaviour, a prank in the strictest definition of the term is a performance that deploys a very specific set of strategies. It is an act of trickery, mischief, or deceit, that must be taken as real, and momentarily cause real fear, anger or worry for an unwitting spectator-become-performer, who is meant to play along until the trick is revealed and their response can be represented back to the prankster, other spectators, or society as a whole, either for the sake of entertainment or for the sake of commentary on a cultural phenomenon. A prank, in this sense, deliberately blurs the boundaries between daily and dramatic performance. It creates a moment of uncertainty, in which both the prankster’s ability to be creative, clever, or culturally astute, and the prankee’s ability to play along, discern the trick, discern the point of the trick, and, in the end, be duped, be a good sport, or even play/pay the prankster back, are both put to the test. In this paper, I consider a number of pranking traditions popular where I am in Australia, from the community-building pranks of footballers, bucks parties and ‘drop bear’ tales told to tourists, to the more controversial pranks of radio shock jocks, activists and artists. I use performance, spectatorship and ethical theory to examine the engagement between prankster, pranked spectator, and other spectators, in this most distinctive sort of community-driven performance practice, and the way it builds and breaks status, social and other sorts of relationships within and between specific communities.

Establishing and maintaining social connectivity: An understanding of the lived experiences of older adults residing in regional and rural communities

- Objective To better understand how to plan for an ageing demographic that resides in ever-changing community typologies. Design: Semi-structured in-depth interviews. - Setting Community settings in rural and regional towns in Queensland. - Participants Twenty-two people aged over 65 years living in regional and rural Australia. - Interventions Qualitative study of social connectedness. - Main outcome measure(s) Thematic qualitative analysis. - Results Formal and informal social contact, through family, friends and social groups, was found to be important to the everyday lives of the participants. - Conclusions Social connections for older adults are important in maintaining independence and community engagement.

Evaluating unmanned aircraft systems for deployment in plant biosecurity

This report provides a qualitative evaluation of Unmanned Aircraft Systems (UAS) and on-board sensor technology for use in plant biosecurity in the Australian context. The more general term UAS describes both the Unmanned Aerial Vehicle (UAV) and all supporting components required to operate it. This may include a ground station, operator or pilot, and a launch and recovery device for example. The focus is to identify how and under what circumstances UAS may be useful for plant biosecurity. This can be used to help guide future decisions regarding investment in UAS for plant biosecurity.

An Australian native plant: A novel antimicrobial for the treatment of MRSA

Chronic wounds, often associated with venous and arterial ulcers, diabetes and pressure sores, is an area of great concern. In Australia, the cost of treating chronic wounds is conservatively estimated at $285 million/annum for the treatment of pressure ulcers and $654 million annually for the treatment and management of leg ulcers. Current figures indicate that more than seven million people suffer from chronic wounds worldwide with Australians accounting for approximately 600,000 of this number. Bacterial infection of the wound site is a major issue as contamination of a chronic wound with methicillin-resistant Staphylococcus aureus (MRSA) significantly delays wound healing. Further, once systemic, current antibiotic therapies capable of treating the infection are limited. Aboriginal bush medicine has been used for thousands of years for the treatment of wounds and sores. Hence, we selected a native Australian plant to evaluate its bactericidal activity against MRSA.

Plant biology: Coding in non-coding RNAs

The discovery of peptides encoded by what were thought to be non-coding – or 'junk' – regions of precursors to microRNA sequences reveals a new layer of gene regulation. These sequences may not be junk, after all.

Engaging communities to make the big switch

Stepping out on the streets of Townsville, where the sun shines for 300 days a year, you can feel a buzz in the air. But it’s not just the sunshine, booming development or new esplanade that has this North Queensland city excited. There’s a groundswell of green activity as residents embrace ‘Townsville Solar City’ – the only Queensland city participating in the Federal Government’s Solar Cities program. Keen to create a more sustainable future, this community is participating in a range of initiatives led by Ergon Energy and Townsville City Council. These activities aim to reduce energy use, increase solar energy capacity and cut annual greenhouse gas emissions by more than 50 000 tonnes.