Suppression of cluster ions during particle formation events in the atmosphere

Cluster ions and charged and neutral nanoparticle concentrations were monitored using a neutral cluster and air ion spectrometer (NAIS) over a period of one year in Brisbane, Australia. The study yielded 242 complete days of usable data, of which particle formation events were observed on 101 days. Small, intermediate and large ion concentrations were evaluated in real time. In the diurnal cycle, small ion concentration was highest during the second half of the night while large ion concentrations were a maximum during the day. The small ion concentration showed a decrease when the large ion concentration increased. Particle formation was generally followed by a peak in the intermediate ion concentration. The rate of increase of intermediate ions was used as the criteria for identifying particle formation events. Such events were followed by a period of growth to larger sizes and usually occurred between 8 am and 2 pm. Particle formation events were found to be related to the wind direction. The gaseous precursors for the production of secondary particles in the urban environment of Brisbane have been shown to be ammonia and sulfuric acid. During these events, the nanoparticle number concentrations in the size range 1.6 to 42 nm, which were normally lower than 1x104 cm-3, often exceeded 5x104 cm-3 with occasional values over 1x105 cm-3. Cluster ions generally occurred in number concentrations between 300 and 600 cm-3 but decreased significantly to about 200 cm-3 during particle formation events. This was accompanied by an increase in the large ion concentration. We calculated the fraction of nanoparticles that were charged and investigated the occurrence of possible overcharging during particle formation events. Overcharging is defined as the condition where the charged fraction of particles is higher than in charge equilibrium. This can occur when cluster ions attach to neutral particles in the atmosphere, giving rise to larger concentrations of charged particles in the short term. Ion-induced nucleation is one of the mechanisms of particle formation in the atmosphere, and overcharging has previously been considered as an indicator of this process. The possible role of ions in particle formation was investigated.

Corner and finger formation in Hele-Shaw flow with kinetic undercooling regularisation

We examine the effect of a kinetic undercooling condition on the evolution of a free boundary in Hele--Shaw flow, in both bubble and channel geometries. We present analytical and numerical evidence that the bubble boundary is unstable and may develop one or more corners in finite time, for both expansion and contraction cases. This loss of regularity is interesting because it occurs regardless of whether the less viscous fluid is displacing the more viscous fluid, or vice versa. We show that small contracting bubbles are described to leading order by a well-studied geometric flow rule. Exact solutions to this asymptotic problem continue past the corner formation until the bubble contracts to a point as a slit in the limit. Lastly, we consider the evolving boundary with kinetic undercooling in a Saffman--Taylor channel geometry. The boundary may either form corners in finite time, or evolve to a single long finger travelling at constant speed, depending on the strength of kinetic undercooling. We demonstrate these two different behaviours numerically. For the travelling finger, we present results of a numerical solution method similar to that used to demonstrate the selection of discrete fingers by surface tension. With kinetic undercooling, a continuum of corner-free travelling fingers exists for any finger width above a critical value, which goes to zero as the kinetic undercooling vanishes. We have not been able to compute the discrete family of analytic solutions, predicted by previous asymptotic analysis, because the numerical scheme cannot distinguish between solutions characterised by analytic fingers and those which are corner-free but non-analytic.

Changes in teachers’ behaviour in secondary science education : implementing a standards-referenced national curriculum

There is substantial attention worldwide to the quality of secondary school teaching in STEM in Education. This paper reports on the use of Outcome Mapping (OM) as an approach to guide and monitor change in teacher practice and a visual tool, shaped as a Star, to benchmark and monitor this behaviour. OM and the visual tool were employed to guide and document three secondary teachers’ behaviour as they planned, implemented and assessed a science unit in the new Australian standards-referenced curriculum. Five key outcome markers in the teachers’ behaviour were identified together with progress markers — cumulative qualitative indicators — leading to these outcomes. The use of a Star to benchmark and track teachers’ behaviours was particularly useful because it showed teacher behaviour on multiple dimensions simultaneously at various points in time. It also highlighted priorities in need of further attention and provided a pathway to achievement. Hence, OM and the Star representation provide both theoretical and pragmatic approaches to enhancing quality in STEM teaching.

Influence of the diesel fuel sulfur content on the formation of nanoparticles

In recent years fine and ultra fine particles emitted from internal combustion engines have attracted an increasing level of attention. This attention has arisen from epidemiological studies conducted by a number of research groups and pointing to the health effects resulting from inhalation of fine particles. Previous studies on the influence of fuel sulfur level on diesel vehicle emissions were mainly concentrated on particle mass emissions. This study aims at investigating the influence of the reduction of diesel fuel sulfur level on the emission and formation of nanoparticles

Performance government : activating and regulating the self-governing capacities of teachers and school leaders

This article analyses ‘performance government’ as an emergent form of rule in advanced liberal democracies. It discloses how teachers and school leaders in Australia are being governed by the practices of performance government which centre on the recently established Australian Institute for Teaching and School Leadership (AITSL) and are given direction by two major strategies implicit within the exercise of this form of power: activation and regulation. Through an ‘analytics of government’ of these practices, the article unravels the new configurations of corporatized expert and academic knowledge—and their attendant methods of application—by which the self-governing capacities of teachers and school leaders are being activated and regulated in ways that seek to optimize the performance of these professionals. The article concludes by outlining some of the dangers of performance government for the professional freedom of educators and school leaders.

The role of the yeast cleavage and polyadenylation factor subunit Ydh1p/Cft2p in pre-mRNA 3'-end formation

Cleavage and polyadenylation factor (CPF) is a multi‐protein complex that functions in pre‐mRNA 3′‐end formation and in the RNA polymerase II (RNAP II) transcription cycle. Ydh1p/Cft2p is an essential component of CPF but its precise role in 3′‐end processing remained unclear. We found that mutations in YDH1 inhibited both the cleavage and the polyadenylation steps of the 3′‐end formation reaction in vitro. Recently, we demonstrated that an important function of CPF lies in the recognition of poly(A) site sequences and RNA binding analyses suggesting that Ydh1p/Cft2p interacts with the poly(A) site region. Here we show that mutant ydh1 strains are deficient in the recognition of the ACT1 cleavage site in vivo. The C‐terminal domain (CTD) of RNAP II plays a major role in coupling 3′‐end processing and transcription. We provide evidence that Ydh1p/Cft2p interacts with the CTD of RNAP II, several other subunits of CPF and with Pcf11p, a component of CF IA. We propose that Ydh1p/Cft2p contributes to the formation of important interaction surfaces that mediate the dynamic association of CPF with RNAP II, the recognition of poly(A) site sequences and the assembly of the polyadenylation machinery on the RNA substrate.

The brain-specific microRNA miR-128b regulates the formation of fear-extinction memory

MicroRNAs are small non-coding RNAs that mediate post-transcriptional gene silencing. Fear-extinction learning in C57/Bl6J mice led to increased expression of the brain-specific microRNA miR-128b, which disrupted stability of several plasticity-related target genes and regulated formation of fear-extinction memory. Increased miR-128b activity may therefore facilitate the transition from retrieval of the original fear memory toward the formation of a new fear-extinction memory.

Teacher education targeting high-poverty schools : the National Exceptional Teachers for Disadvantaged Schools program

This paper examines the Exceptional Teachers for Disadvantaged Schools (ETDS) program and demonstrates how the outcomes from this teacher education model targeting high-poverty schools have been used to expand the model across other Australian universities. The paper outlines the parameters of ETDS and stresses the importance to the program of academic excellence, a modified teacher education curriculum, targeted practicums and a network of jurisdictional and school-based partnerships. The paper presents data from ETDS that demonstrates 90% of graduates have secured employed as teachers within high-poverty Australian schools. The paper concludes by outlining the impact of philanthropic funding (2 million dollars AUD) that will allow the expansion of the ETDS model into other teacher education universities across Australia.

Ageing in Fiji : how older teachers perceive ageing and their lives

Worldwide the population is ageing and data concerning how people want to age actively is limited. The paper is a description of an inductive interpretive-descriptive study of how a sample of older retired teachers in Fiji viewed ageing and their lives as older people. The objectives were to determine and describe perceptions of ageing held by a sample of retired teachers. The methodology consisted of responses to an open ended questionnaire similar to a phenomenographic approach and the analysis was interpretive – descriptive. A purposive sample of 30 retired teachers between the ages of 55 and 60 responded to the questionnaire. The results indicate that most of the respondents were positive about lifelong learning and in particular learning new things; that they were involved in a range of post retirement activities for personal and financial reasons; that there were some barriers and facilitators to their activities; that they generally accepted ageing and being older; and that more should be done by Government and other agencies to provide for a better life for older people in Fiji. These results should be considered in future planning for ageing populations in Fiji, the Pacific region and in other developing countries.

Child observation as teachers' work in contemporary Australian early childhood programs

This article reports data from a study of how teachers use child observations in one State in Australia. It argues that the current economic and political climate has meant changes for most early childhood settings catering for children prior to school entry. How teachers in these various settings deal with changes in relation to child observation depends on the contexts in which they work. The paper suggests that the purpose of observing children is changing and that traditionally accepted ways of writing child observations may be under threat.

A contextual analysis of secondary home economic teachers' agency in a time of mandatory curriculum change

This qualitative research explored secondary Home Economics teachers' perceptions of their teacher agency to influence classroom, department and school level curriculum decision making. Teachers responded to curriculum change with proactive, reactive and/or passive agency. Findings indicated that teachers' perceptions of their classroom agency remained high. However, agency decreased at department and school levels. Recent changes in schools as a result of the Australian Curriculum; NAPLAN and Queensland Studies Authority have resulted in changes that have been detrimental to teacher agency. Agency was enacted differently depending on whether change was teacher initiated or mandated by authority.

Muramidases found in the foregut microbiome of the Tammar wallaby can direct cell aggregation and biofilm formation

We describe here the role of muramidases present in clones of metagenomic DNA that result in cell aggregation and biofilm formation by Escherichia coli. The metagenomic clones were obtained from uncultured Lachnospiraceae-affiliated bacteria resident in the foregut microbiome of the Tammar wallaby. One of these fosmid clones (p49C2) was chosen for more detailed studies and a variety of genetic methods were used to delimit the region responsible for the phenotype to an open reading frame of 1425 bp. Comparative sequence analysis with other fosmid clones giving rise to the same phenotype revealed the presence of muramidase homologues with the same modular composition. Phylogenetic analysis of the fosmid sequence data assigned these fosmid inserts to recently identified, but uncultured, phylogroups of Lachnospiraceae believed to be numerically dominant in the foregut microbiome of the Tammar wallaby. The muramidase is a modular protein containing putative N-acetylmuramoyl--alanine amidase and an endo-β-N-acetylglucosaminidase catalytic module, with a similar organization and functional properties to some Staphylococcal autolysins that also confer adhesive properties and biofilm formation. We also show here that the cloned muramidases result in the production of extracellular DNA, which appears to be the key for biofilm formation and autoaggregation. Collectively, these findings suggest that biofilm formation and cell aggregation in gut microbiomes might occur via the concerted action of carbohydrate-active enzymes and the production of extracellular DNA to serve as a biofilm scaffold.

UpaH Is a newly identified autotransporter protein That contributes to biofilm formation and bladder colonization by Uropathogenic Escherichia coli CFT073

Escherichia coli is the primary cause of urinary tract infection (UTI) in the developed world. The major factors associated with virulence of uropathogenic E. coli (UPEC) are fimbrial adhesins, which mediate specific attachment to host receptors and trigger innate host responses. Another group of adhesins is represented by the autotransporter (AT) subgroup of proteins. In this study, we identified a new AT-encoding gene, termed upaH, present in a 6.5-kb unannotated intergenic region in the genome of the prototypic UPEC strain CFT073. Cloning and sequencing of the upaH gene from CFT073 revealed an intact 8.535-kb coding region, contrary to the published genome sequence. The upaH gene was widely distributed among a large collection of UPEC isolates as well as the E. coli Reference (ECOR) strain collection. Bioinformatic analyses suggest β-helix as the predominant structure in the large N-terminal passenger (α) domain and a 12-strand β-barrel for the C-terminal β-domain of UpaH. We demonstrated that UpaH is expressed at the cell surface of CFT073 and promotes biofilm formation. In the mouse UTI model, deletion of the upaH gene in CFT073 and in two other UPEC strains did not significantly affect colonization of the bladder in single-challenge experiments. However, in competitive colonization experiments, CFT073 significantly outcompeted its upaH isogenic mutant strain in urine and the bladder.

Determination of glutathione transferase (GSTT1-1) activities in different tissues based on formation of radioactive metabolites using 35S-glutathione

A new system has been developed to determine enzyme activities of glutathione transferase θ (GSTT1-1) based on radiometric product detection resulting from the enzymic reaction of methyl chloride with 35S-labelled glutathione. In principle, the method is universally applicable for determination of glutathione transferase activities towards a multiplicity of substrates. The method distinguishes between erythrocyte GSTT1-1 activities of human 'non-conjugators', 'low conjugators' and 'high conjugators'. Application to cytosol preparations of livers and kidneys of male and female Fischer 344 and B6C3F1 mice reveals differential GSTT1-1 activities in hepatic and renal tissues. These ought to be considered in species-specific modellings of organ toxicities of chlorinated hydrocarbons.

Australian boarding school supervisors : a voluntary position?

This paper aims to examine how Australian boarding supervisors (particularly non-teachers) are defined in regards to employment. The practices of Queensland’s School X (real name withheld) are used as an example of the difficult issues involved – although whether this case study is repeated elsewhere in the industry would take further research. The paper illustrates that the employment of boarding supervisors is dealt with at a basic level by a modern award, however its provisions do not represent what occurs in practice. If there is no enterprise bargain which improves upon the award, two possible explanations are put forward to explain the difference between award conditions and practice. The first is that the contract between boarding supervisors may not be one of employment. Relevant case law regarding whether a person is an employee or independent contractor is examined, and when applied to a typical boarding situation, it is concluded that any contract should be one of employment. The second explanation is that there is no legal contract at all between boarding supervisors and a school. Drawing on School X’s example where supervisors were classed as ‘volunteers’, the paper examines what the legal effect of that term might be. It could be seen to be a denial of an intention to create legal relations, a critical element in contract formation. Again, important cases are analysed on the topic of intention, and applied to a boarding context. It is argued that given the objective circumstances of a typical agreement, there is an intention to create legal relations. In particular, a little known Queensland case involving the non-employment status of boarding supervisors, which may be the cause of the confusion, is critically examined to determine its usefulness in answering the issue. Finally, the implications of not classifying boarding supervisors as employees are briefly discussed.