Formation of specialized propagules resistant to desiccation and cryopreservation in the threatened moss Ditrichum plumbicola (ditrichales, bryopsida)

Background and Aims Successful cryopreservation of bryophytes is linked to intrinsic desiccation tolerance and survival can be enhanced by pre-treatment with abscisic acid (ABA) and sucrose. The pioneer moss Ditrichum plumbicola is naturally subjected to desiccation in the field but showed unexpectedly low survival of cryopreservation, as well as a poor response to pre-treatment. The effects of the cryopreservation protocol on protonemata of D. plumbicola were investigated in order to explore possible relationships between the production in vitro of cryopreservation-tolerant asexual propagules and the reproductive biology of D. plumbicola in nature. Methods Protonemata were prepared for cryopreservation using a four-step protocol involving encapsulation in sodium alginate, pre-treatment for 2 weeks with ABA and sucrose, desiccation for 6 h and rapid freezing in liquid nitrogen. After each stage, protonemata were prepared for light and electron microscopy and growth on standard medium was monitored. Further samples were prepared for light and electron microscopy at intervals over a 24-h period following removal from liquid nitrogen and re-hydration. Key Results Pre-treatment with ABA and sucrose caused dramatic changes to the protonemata. Growth was arrested and propagules induced with pronounced morphological and cytological changes. Most cells died, but those that survived were characterized by thick, deeply pigmented walls, numerous small vacuoles and lipid droplets in their cytoplasm. Desiccation and cryopreservation elicited no dramatic cytological changes. Cells returned to their pre-dehydration and cryopreservation state within 2 h of re-hydration and/or removal from liquid nitrogen. Regeneration was normal once the ABA/sucrose stimulus was removed. Conclusions The ABA/sucrose pre-treatment induced the formation of highly desiccation- and cryopreservation-tolerant propagules from the protonemata of D. plumbicola. This parallels behaviour in the wild, where highly desiccation-tolerant rhizoids function as perennating organs allowing the moss to endure extreme environmental conditions. An involvement of endogenous ABA in the desiccation tolerance of D. plumbicola is suggested.

The function of the RNA-binding protein TEL1 in moss reveals ancient regulatory mechanisms of shoot development

The shoot represents the basic body plan in land plants. It consists of a repeated structure composed of stems and leaves. Whereas vascular plants generate a shoot in their diploid phase, non-vascular plants such as mosses form a shoot (called the gametophore) in their haploid generation. The evolution of regulatory mechanisms or genetic networks used in the development of these two kinds of shoots is unclear. TERMINAL EAR1-like genes have been involved in diploid shoot development in vascular plants. Here, we show that disruption of PpTEL1 from the moss Physcomitrella patens, causes reduced protonema growth and gametophore initiation, as well as defects in gametophore development. Leafy shoots formed on ΔTEL1 mutants exhibit shorter stems with more leaves per shoot, suggesting an accelerated leaf initiation (shortened plastochron), a phenotype shared with the Poaceae vascular plants TE1 and PLA2/LHD2 mutants. Moreover, the positive correlation between plastochron length and leaf size observed in ΔTEL1 mutants suggests a conserved compensatory mechanism correlating leaf growth and leaf initiation rate that would minimize overall changes in plant biomass. The RNA-binding protein encoded by PpTEL1 contains two N-terminus RNA-recognition motifs, and a third C-terminus non-canonical RRM, specific to TEL proteins. Removal of the PpTEL1 C-terminus (including this third RRM) or only 16–18 amino acids within it seriously impairs PpTEL1 function, suggesting a critical role for this third RRM. These results show a conserved function of the RNA-binding PpTEL1 protein in the regulation of shoot development, from early ancestors to vascular plants, that depends on the third TEL-specific RRM.

Improving daylighting performance of mirrored light pipes

This paper assesses and compares the performances of two daylight collection strategies, one passive and one active, for large-scale mirrored light pipes (MLP) illuminating deep plan buildings. Both strategies use laser cut panels (LCP) as the main component of the collection system. The passive system comprises LCPs in pyramid form, whereas the active system uses a tiled LCP on a simple rotation mechanism that rotates 360° in 24 hours. Performance is assessed using scale model testing under sunny sky conditions and mathematical modelling. Results show average illuminance levels for the pyramid LCP ranging from 50 to 250 lux and 150 to 200 lux for the rotating LCPs. Both systems improve the performance of a MLP. The pyramid LCP increases the performance of a MLP by 2.5 times and the rotating LCP by 5 times, when compared to an open pipe particularly for low sun elevation angles.

The new world of work and employment: fitness workers and what they want from the employment relationship

This paper reports on an empirically based study of the Queensland (Australia) health and fitness industry over 15 years (1993 -2008). This study traces the development of the new occupation of fitness instructor in a service industry which has evolved si nce the 1980s and is embedded in values of consumption and individualism. It is the new world of work. The data from the 1993 study was historically significant, capturing the conditions o f employment in an unregulated setting prior to the introduction of the first industrial a ward in that industry in 1994. Fitness workers bargained directly with employers over all a spects of the employment relationship without the constraints of industrial regulation or the presence of trade unions. The substantive outcomes of the employment relationship were a direct reflection of m anagerial prerogative and worker orientation and preference, and did not reflect the rewards and outcomes traditionally found in Australian workplaces. While the focus of the 1993 research was on exploring the employment relationship in a deregulated environment, an unusual phenomenon was identified: fitness workers happily trading-off what would be considere d standard working conditions for the opportunity to work (‘take the stage’). Since then, several streams of literature have evolved providing a new context for understanding this phenomenon in the fitness industry, including: the sociology of the body (Shilling 1993; Turner 1996); emotional (Hochschild 1984) and aesthetic labour (Warhurst et al 2000); the so cial relations of production and space (Lefebvre 1991; Moss 1995); body history (Helps 2007); the sociology of consumption (Saunders 1988; Baudrillard 1998; Ritzer 2004); and work identity (Du Gay 1996; Strangleman 2004). The 2008 survey instrument replicated the 1993 study but was additionally informed b y the new literature. Surveys were sent to 310 commercial fitness centres and 4,800 fitness workers across Queensland. Worker orientation appears unchanged, and industry working conditions still seem atypical despite regulation si nce 1994. We argue that for many fitness workers the goal is to gain access to the fitness centre economy. For this they are willing to trade-off standard conditions of employment, and exchange traditional employm ent rewards for m ore intrinsic psycho-social rewards gained the through e xp o sure of their physical capital (Bourdieu 1984) o r bo dily prowess to the adoration o f their gazing clients. Building on the tradition of emotional labour and aesthetic labour, this study introduces the concept of ocularcentric labour: a state in which labour’s quest for the psychosocial rewards gained from their own body image shapes the employment relationship. With ocularcentric labour the p sycho-social rewards have greater value for the worker than ‘hard’, core conditions of employment, and are a significant factor in bargaining and outcomes, often substituting fo r direct earnings. The wo rkforce profile (young, female, casual) and their expectations (psycho-social rewards of ado ration and celebrity) challenge traditional trade unions in terms of what they can deliver, given the fitness workers’ willingness to trade-off minimum conditions, hard-won by unions.

Integrating engineering education within the elementary and middle school mathematics curriculum

Many nations are experiencing a decline in the number of graduating engineers, an overall poor preparedness for engineering studies in tertiary institutions, and a lack of diversity in the field. Given the increasing importance of mathematics, science, engineering, and technology in our world, it is imperative that we foster an interest and drive to participate in engineering from an early age. This discussion paper argues for the integration of engineering education within the elementary and middle school mathematics curricula. In doing so, we offer a definition of engineering education and address its core goals; consider some perceptions of engineering and engineering education held by teachers and students; and offer one approach to promoting engineering education within the elementary and middle school mathematics curriculum, namely through mathematical modeling.

The phenomenology of utopia : reimagining the political

This thesis argues that the end of Soviet Marxism and a bipolar global political imaginary at the dissolution of the short Twentieth Century poses an obstacle for anti-systemic political action. Such a blockage of alternate political imaginaries can be discerned by reading the work of Francis Fukuyama and "Endism" as performative invocations of the closure of political alternatives, and thus as an ideological proclamation which enables and constrains forms of social action. It is contended that the search through dialectical thought for a competing universal to posit against "liberal democracy" is a fruitless one, because it reinscribes the terms of teleological theories of history which work to effect closure. Rather, constructing a phenomenological analytic of the political conjuncture, the thesis suggests that the figure of messianism without a Messiah is central to a deconstructive reframing of the possibilities of political action - a reframing attentive to the rhetorical tone of texts. The project of recovering the political is viewed through a phenomenological lens. An agonistic political distinction must be made so as to memorialise the remainders and ghosts of progress, and thus to gesture towards an indeconstructible justice which would serve as a horizon for the articulation of an empty universal. This project is furthered by a return to a certain phenomenology inspired by Cornelius Castoriadis, Claude Lefort, Maurice Merleau-Ponty and Ernesto Laclau. The thesis provides a reading of Jacques Derrida and Walter Benjamin as thinkers of a minor universalism, a non-prescriptive utopia, and places their work in the context of new understandings of religion and the political as quasi-transcendentals which can be utilised to think through the aporias of political time in order to grasp shards of meaning. Derrida and Chantal Mouffe's deconstructive critique and supplement to Carl Schmitt's concept of the political is read as suggestive of a reframing of political thought which would leave the political question open and thus enable the articulation of social imaginary significations able to inscribe meaning in the field of political action. Thus, the thesis gestures towards a form of thought which enables rather than constrains action under the sign of justice.

Psychosocial predictors of the use of enhanced podcasting in student learning

The current study examined the influence of psychosocial constructs, from a theory of planned behavior (TPB) perspective, to predict university students’ (N = 159) use of a newly offered on-line learning tool, enhanced podcasts. Pre-semester, students completed questionnaires assessing the TPB predictors (attitude, subjective norm, perceived behavioral control) related to intended enhanced podcast use until the middle of semester. Mid-semester, students completed similar items relating to podcast use until the end of semester. Self-report measures of podcast use were obtained at the middle and end of semester. At both time points, students’ attitudes predicted their intentions and, at the initial time point, subjective norm also predicted intended podcast use. An examination of the beliefs underlying attitudes, the only construct to predict intentions at both time points, revealed differences between those students higher, rather than lower on intentions to use the podcasts, especially for the perceived educational benefits of podcast use later in the semester. Intentions to use enhanced podcasting only predicted self-reported use in the second half of the semester. Overall, this study identified some of the determinants which should be considered by those aiming to encourage student use of novel on-line educational tools.

Tango Femme : placing the lesbian centre stage

The play Tango Femme places the lesbian centre stage by creating characters, narrative and drama in the world of same-sex dancing. The accompanying exegesis examines the problems and issues associated with creating lesbian characters in theatre, using a synthesized, practice led methodology. During the process of imagining, constructing and writing my case study play, I have investigated lesbian theatre productions and companies in order to make sense of my personal experiences in the theatre world. I have also reflected on the lesbian as represented in mainstream theatre and popular culture. Through journal writing and contemplation, I have sought to identify difficulties inherent in writing this type of play, using my own journey as a focus. My study illuminates the historical and sociological circumstances in the eighties and nineties in Australia and concludes that as a lesbian playwright I was caught between a rock and a hard place: the rock being lesbian theatre on a community level, as defined and attended primarily by separatist lesbians, and the hard place being mainstream theatre, located within the dominant, heteronormative discourse. The play Tango Femme has developed in conversation with my reflective practice and research and is written in the space outside the master narrative as "an instance of lesbian discourse" (Davy 1996, p.153).

Gender

The OED informs us that “gender” has at its root the Latin genus, meaning “race, kind,” and emerges as early as the fifth century as a term for differentiating between types of (especially) people and words. In the following 1500 years, gender appears in linguistic and biological contexts to distinguish types of words and bodies from one another, as when words in Indo-European languages were identified as masculine, feminine, or neuter, and humans were identified as male or female. It is telling that gender has historically (whether overtly or covertly) been a tool of negotiation between our understandings of bodies, and meanings derived from and attributed to them. Within the field of children’s literature studies, as in other disciplines, gender in and of itself is rarely the object of critique. Rather, specific constructions of gender structure understandings of subjectivity; allow or disallow certain behaviors or experiences on the basis of biological sex; and dictate a specific vision of social relations and organization. Critical approaches to gender in children’s literature have included linguistic analysis (Turner-Bowker; Sunderland); analysis of visual representations (Bradford; Moebius); cultural images of females (Grauerholz and Pescosolido); consideration of gender and genre (Christian-Smith; Stephens); ideological (Nodelman and Reimer); psychoanalytic (Coats); discourse analysis (Stephens); and masculinity studies (Nodelman) among others. In the adjacent fields of education and literacy studies, gender has been a sustained point of investigation, often deriving from perceived gendering of pedagogical practices (Lehr) or of reading preferences and competencies, and in recent years, perceptions of boys as “reluctant readers” (Moss). The ideology of patriarchy has primarily come under critical scrutiny 2 because it has been used to locate characters and readers within the specific binary logic of gender relations that historically subordinated the feminine to the masculine. Just as feminism might be broadly defined as resistance to existing power structures, a gendered reading might be broadly defined as a “resistant reading” in that it most often reveals or contests that which a text assumes to be the norm.

Toward robust image detection of crown-of-thorns starfish for autonomous population monitoring

Robust texture recognition in underwater image sequences for marine pest population control such as Crown-Of-Thorns Starfish (COTS) is a relatively unexplored area of research. Typically, humans count COTS by laboriously processing individual images taken during surveys. Being able to autonomously collect and process images of reef habitat and segment out the various marine biota holds the promise of allowing researchers to gain a greater understanding of the marine ecosystem and evaluate the impact of different environmental variables. This research applies and extends the use of Local Binary Patterns (LBP) as a method for texture-based identification of COTS from survey images. The performance and accuracy of the algorithms are evaluated on a image data set taken on the Great Barrier Reef.

Framework for the long-term operation of a mobile robot via the Internet

This paper describes an autonomous docking system and web interface that allows long-term unaided use of a sophisticated robot by untrained web users. These systems have been applied to the biologically inspired RatSLAM system as a foundation for testing both its long-term stability and its practicality. While docking and web interface systems already exist, this system allows for a significantly larger margin of error in docking accuracy due to the mechanical design, thereby increasing robustness against navigational errors. Also a standard vision sensor is used for both long-range and short-range docking, compared to the many systems that require both omni-directional cameras and high resolution Laser range finders for navigation. The web interface has been designed to accommodate the significant delays experienced on the Internet, and to facilitate the non- Cartesian operation of the RatSLAM system.

Obstacle detection using optical flow

Motion has been examined in biology to be a critical component for obstacle avoidance and navigation. In particular, optical flow is a powerful motion cue that has been exploited in many biological systems for survival. In this paper, we investigate an obstacle detection system that uses optical flow to obtain range information to objects. Our experimental results demonstrate that optical flow is capable of providing good obstacle information but has obvious failure modes. We acknowledge that our optical flow system has certain disadvantages and cannot be solely used for navigation. Instead, we believe that optical flow is a critical visual subsystem used when moving at reason- able speeds. When combined with other visual subsystems, considerable synergy can result.

Fuzzy associative memory for humanoid robot joint control

Traditional approaches to joint control required accurate modelling of the system dynamic of the plant in question. Fuzzy Associative Memory (FAM) control schemes allow adequate control without a model of the system to be controlled. This paper presents a FAM based joint controller implemented on a humanoid robot. An empirically tuned PI velocity control loop is augmented with this feed forward FAM, with considerable reduction in joint position error achieved online and with minimal additional computational overhead.