Heterotrimeric G protein γ subunits provide functional selectivity in Gβγ dimer signaling in arabidopsis

The Arabidopsis thaliana heterotrimeric G protein complex is encoded by single canonical Galpha and Gbeta subunit genes and two Ggamma subunit genes (AGG1 and AGG2), raising the possibility that the two potential G protein complexes mediate different cellular processes. Mutants with reduced expression of one or both Ggamma genes revealed specialized roles for each Ggamma subunit. AGG1-deficient mutants, but not AGG2-deficient mutants, showed impaired resistance against necrotrophic pathogens, reduced induction of the plant defensin gene PDF1.2, and decreased sensitivity to methyl jasmonate. By contrast, both AGG1- and AGG2-deficient mutants were hypersensitive to auxin-mediated induction of lateral roots, suggesting that Gbetagamma1 and Gbetagamma2 synergistically inhibit auxin-dependent lateral root initiation. However, the involvement of each Ggamma subunit in this root response differs, with Gbetagamma1 acting within the central cylinder, attenuating acropetally transported auxin signaling, while Gbetagamma2 affects the action of basipetal auxin and graviresponsiveness within the epidermis and/or cortex. This selectivity also operates in the hypocotyl. Selectivity in Gbetagamma signaling was also found in other known AGB1-mediated pathways. agg1 mutants were hypersensitive to glucose and the osmotic agent mannitol during seed germination, while agg2 mutants were only affected by glucose. We show that both Ggamma subunits form functional Gbetagamma dimers and that each provides functional selectivity to the plant heterotrimeric G proteins, revealing a mechanism underlying the complexity of G protein-mediated signaling in plants.

Manage one beach or two? Movements and space-use of the threatened hooded plover (Thinornis rubricollis) in south-eastern Australia

An understanding of space use and dispersal of a wildlife species is essential for effective management. We examined the movements of a beach-dwelling, threatened population of hooded plover (Thinornis rubricollis) in southern central Victoria, Australia, by analysing sightings of colour-banded birds (4897 sightings; 194 birds tracked for up to 9 years). Most movements were relatively short (5050 ± 305 m), with 61.4% <1 km and 95.3% <20 km; they lacked directional or sexual bias. The extent of coastline used by individual birds was 47.8 ± 58.0 km. Regional differences in average distances moved by adults were apparent. For adults, movement rates (mean distance per day) were higher during the non-breeding season than during the breeding season. Non-breeding adults generally remained close to their partners (non-breeding, 456.3 ± 163.9 m; breeding, 148.2 ± 45.3 m). Largest flock sizes were recorded during the non-breeding period, and flocking was not uniformly distributed along the coast but appeared to be concentrated in particular locations. The frequency of pair cohesion (i.e. when the distance between partners was zero on a given day) was similar during the breeding (69.6%) and non-breeding seasons (67.7%). Breeding territories (kernel analysis) were 36.7 ± 5.7 ha and overlapped from year to year in all cases (23 pairwise comparisons; 47.9 ± 7.1% overlap). The high fidelity and constancy of territories confirms they warrant ongoing management investment, although the species relies on a matrix of breeding and non-breeding sites. The latter appear to occur in specific parts of the coast and warrant enhanced protection and more research attention. Fragmentation of the breeding population might occur where habitat is rendered unsuitable for > ~50 km.

Bare life in second life : Giorgio Agamben's politics in performance

This paper describes and analyzes the necessary misreadings of Giorgio Agamben’s account of ‘bare life’ in a recent performance in Melbourne, Australia. The ‘Bare Life’ project deals with Australia’s treatment of asylum seekers with reference to Agamben’s work on sovereign power and uses the on-line second life world as both a metaphor for the refugee’s desire for a new life, and a literal site of performance. The development showing explored the interactions between live performance and second life avatars in real time. This paper deals with the philosophical, ethical and practical problems that emerged during the development, and argues that the ‘misreading’ is an inevitable, but useful part of finding ways to embody philosophical and political ideas in performance.

Construction supply chain modeling : a research review and interdisciplinary research agenda

Supply chain management has emerged as a popular and useful concept in the construction industry and research community since the mid 1990s. Research in construction supply chain management draws from a broad range of disciplines, notably: (1) industrial organization economics to better understand market structure and forces and their effect on firm and supply chain behavior and (2) Analytic modeling of supply chains to improve supply chain performance along metrics such as speed, cost, reliability, quality, etc. Both industrial organization and analytic modeling provide useful but
ultimately incomplete perspectives and prescriptions for construction supply chain management. As such, this paper proposes development of an interdisciplinary research agenda that draws from both fields. Towards that agenda, a review of research is presented to introduce the main ideas, relevant literature, and theory and methods in each of the two areas. From these independent reviews, applications that could benefit from a combined perspective are identified and used as a basis for development of an
interdisciplinary research agenda.

‘My history is a tile in a mosaic’ : an interview with Jim Cullen

JIM CULLEN was born in Queens, New York, and attended public schools on Long Island. He received his B.A. in English from Tufts University, and his A.M. and Ph.D. degrees in American Civilization from Brown University. He has taught at a number of colleges and universities, including Harvard and Brown. He is currently a teacher, and serves on the Board of the Trustees, at the Ethical Culture Fieldston School in New York City. Jim is married to historian Lyde Cullen Sizer and has four children.
CONTEXT: Dr Glenn Moore co-ordinates the subject 'Searching for the American Dream’ at The University of Melbourne. For the last nine years he has taken second and third year history students to Boston, New York and Washington, D.C to explore the philosophy of genius loci. Dr Moore gets students to work in food banks, visit homeless shelters, museums and organizes an array of guest speakers with experts such as Boston public defender, Denise Regan, Neera Tanden, Hillary Clinton’s campaign manager and Alec Ross, vice president of One Economy. As the leading expert on the American Dream, with the publication of so many books in American history such as: The American Dream: A Short History of an Idea that Shaped a Nation, Born in the U.S.A.: Bruce Springsteen and the American Tradition and Restless in the Promised Land: Catholics and the American Dream, Jim Cullen has spoken to the students for the last five years. I interviewed him prior to his recent discussion with the students in New York on 5 July 2006 at the Fashion Institute of Technology.

Regulation of insulin signalling by exercise in skeletal muscle

Regular physical activity improves insulin action and is an effective therapy for the treatment and prevention of type 2 diabetes. However, little is known of the mechanisms by which exercise improves insulin action in muscle. These studies investigate the actions of a single bout of exercise and short-term endurance training on insulin signalling. Twenty-four hours following the completion of a single bout of endurance exercise insulin action improved, although greater enhancement of insulin action was demonstrated following the completion of endurance training, implying that cumulative bouts of exercise substantially increase insulin action above that seen from the residual effects of an acute bout of prior exercise. No alteration in the abundance and phosphorylation of proximal members of the insulin-signalling cascade in skeletal muscle, including the insulin receptor and IRS-1 were found. A major finding however, was the significant increase in the serine phosphorylation of a known downstream signalling protein, Akt (1.5 fold, p ≤0.05) following an acute bout of exercise and exercise training. This was matched by the observed increase in protein abundance of SHPTP2 (1.6 fold, p ≤0.05) a protein tyrosine phosphatase, in the cytosolic fraction of skeletal muscle following endurance exercise. These data suggest a small positive role for SHPTP2 on insulin stimulated glucose transport consistent with transgenic mice models. Further studies were aimed at examining the gene expression following a single bout of either resistance or endurance exercise. There were significant transient increases in IRS-2 mRNA concentration in the few hours following a single bout of both endurance and resistance exercise. IRS-2 protein abundance was also observed to significantly increase 24-hours following a single bout of endurance exercise indicating transcriptional regulation of IRS-2 following muscular contraction. One final component of this PhD project was to examine a second novel insulin-signalling pathway via c-Cbl tyrosine phosphorylation that has recently been shown to be essential for insulin stimulated glucose uptake in adipocytes. No evidence was found for the tyrosine phosphorylation of c-Cbl in the skeletal muscle of Zucker rats despite demonstrating significant phosphorylation of the insulin receptor and Akt by insulin treatment and successfully immunoprecipitating c-Cbl protein. Surprisingly, there was a small but significant increase in c-Cbl protein expression following insulin-stimulation, however c-Cbl tyrosine phosphorylation does not appear to be associated with insulin or exercise-mediated glucose transport in skeletal muscle.

Addressing the contradiction between discourse and practice in health promotion

The main theme of this thesis is the contradiction between discourse and practice in health promotion. Many health promoters continue to exert power-over the community through top-down programming whilst at the same time using an emancipatory discourse. The thesis has addressed this contradiction in three parts. The first part determines how the emancipatroty discourse has evolved and eplores the role of social movements in the development of contemporary health discourses and their influence on the legitimisation of empowerment. Central to this discourse is the empowerment of communities. To understand the role of this concept the thesis provides an interpretation of the different meanings of power and community, and the different levels of analysis of empowerment in the context of health promotion programming. The second part identifies the nature of health programming and the dominance of top-down, and to a much lesser extent, bottom-up approaches. The thesis argues that these two approaches are not, and do not have to be, mutually exclusive. To address this issue the thesis presents a new methodology is situated within a framework developed for the accomodation of empowerment goals within health promotion programmes. The study also identifies the organisational areas of influence on the processs of community empowerment and it is these which are used for the assessment of this concept. Both the framework and the methodology address the contradiction in health promotion by making community empowerment operational within a programme context. The third part of the thesis supports the rationale for the design of the methodology with field work in rural Fijian communities. The findings are presented as a composite case study to highlight the experiences of implementing the methodolgy and the main themes that emerged during the field work. the final chapter of the thesis brings together the central themes of the study and draws from these and 'emergent agenda' as a way forward for health promotion research and practice.

Genome - wide association study identifies novel breast cancer susceptibility loci

Breast cancer exhibits familial aggregation, consistent with variation in genetic susceptibility to the disease. Known susceptibility genes account for less than 25% of the familial risk of breast cancer, and the residual genetic variance is likely to be due to variants conferring more moderate risks. To identify further susceptibility alleles, we conducted a two-stage genome-wide association study in 4,398 breast cancer cases and 4,316 controls, followed by a third stage in which 30 single nucleotide polymorphisms (SNPs) were tested for confirmation in 21,860 cases and 22,578 controls from 22 studies. We used 227,876 SNPs that were estimated to correlate with 77% of known common SNPs in Europeans at r² > 0.5. SNPs in five novel independent loci exhibited strong and consistent evidence of association with breast cancer (P < 10^-7). Four of these contain plausible causative genes (FGFR2, TNRC9, MAP3K1 and LSP1). At the second stage, 1,792 SNPs were significant at the P < 0.05 level compared with an estimated 1,343 that would be expected by chance, indicating that many additional common susceptibility alleles may be identifiable by this approach.

Intramuscular determinants of the VO₂ slow component in trained cyclists

Fifteen trained male cyclists had muscle biopsies and performed cycling tests to determine if relationships exist between the oxygen uptake response and various intramuscular variables. It was found that muscle oxidative capacity is better able to explain the oxygen uptake response during high intensity cycling than muscle fiber distribution.

A behavioural analysis of enforced delays in computerised programmed instruction

To evaluate the putative advantages of student self pacing in automated instruction,the studies in this thesis compare the effects of self-paced, and externally-paced, programmed instruction on student accuracy, retention, efficiency, and satisfaction. The results of the experiments show that self-pacing reduced accuracy, retention, and workrates compared to external pacing and indicated that learners often make poor choices about optimum learning conditions. They also show that small changes in the learning environment can result in consistent and substantial changes in learner performance, and that behaviour analysts have an important role to play in the design and implementation of instructional material.

Students' expectations of the virtual maternity clinic

The aim for the Virtual Maternity Clinic (VMC) is to engage students in learning about the role of the midwife and care of women during early pregnancy. The VMC, using Deakin Studies Online as a platform, includes LiveSim, videoed characters and Adobe Flash of four pregnant women with diverse issues. From an evaluation distributed to students prior to access of the VMC to identify their expectations, we found that undergraduate students wanted to learn how to interact with women during early pregnancy, whereas postgraduate students wanted strategies to learn about midwifery practice. Further development of the VMC is progressing to include a suite of programs incorporating the care of women during late pregnancy, labour and birth; and the time after birth.

Effects of starting strategy on 5-min cycling time-trial performance

The importance of pacing for middle-distance performance is well recognized, yet previous research has produced equivocal results. Twenty-six trained male cyclists ( V O_2peak 62.8+5.9 ml ·kg^-1 · min^-1· maximal aerobic power output 340+43 W; mean+s) performed three cycling time-trials where the total external work (102.7+13.7 kJ) for each trial was identical to the best of two 5-min habituation trials. Markers of aerobic and anaerobic metabolism were assessed in 12 participants. Power output during the first quarter of the time-trials was fixed to control external mechanical work done (25.7+3.4 kJ) and induce fast-, even-, and slow-starting strategies (60, 75, and 90 s, respectively). Finishing times for the fast-start time-trial (4:53+0:11 min:s) were shorter than for the even-start (5:04+0:11 min:s; 95% CI=5 to 18 s, effect size=0.65, P 50.001) and slow-start time-trial (5:09+0:11 min:s; 95% CI=7 to 24 s, effect size=1.00, P 50.001). Mean VO₂ during the fast-start trials (4.31+0.51 litres · min^-1) was 0.18+0.19 litres · min^-1 (95% CI=0.07 to 0.30 litres · min^-1, effect size=0.94, P =0.003) higher than the even- and 0.18+0.20 litres · min^-1 (95% CI=0.5 to 0.30 litres · min^-1, effect size=0.86, P =0.007) higher than the slow-start time-trial. Oxygen deficit was greatest during the first quarter of the fast-start trial but was lower than the even- and slow-start trials during the second quarter of the trial. Blood lactate and pH were similar between the three trials. In conclusion, performance during a 5-min cycling time-trial was improved with the adoption of a fast- rather than an even- or slow-starting strategy.

High frequency dielectric response of the ionic liquid N-methyl-N-ethylpyrrolidinium dicyanamide

A study of the room-temperature ionic liquid N-methyl-N-ethylpyrrolidinium dicyanamide by dielectric relaxation spectroscopy over the frequency range 0.2 GHz ≤ ν ≤ 89 GHz has revealed that, in addition to the already known lower frequency processes, there is a broad featureless dielectric loss at higher frequencies. The latter is probably due to the translational (oscillatory) motions of the dipolar ions of the IL relative to each other, with additional contributions from their fast rotation.