An ecology of centre-based child care

The studies in the thesis were derived from a program of research focused on centre-based child care in Australia. The studies constituted an ecological analysis as they examined proximal and distal factors which have the potential to affect children's developmental opportunities (Bronfenbrenner, 1979). The project was conducted in thirty-two child care centres located in south-east Queensland. Participants in the research included staff members at the centres, families using the centres and their children. The first study described the personal and professional characteristics of one hundred and forty-four child care workers, as well as their job satisfaction and job commitment. Factors impinging on the stability of care afforded to children were examined, specifically child care workers' intentions to leave their current position and actual staff turnover at a twelve month follow-up. This is an ecosystem analysis (Bronfenbrenner & Crouter, 1983), as it examined the world of work for carers; a setting not directly involving the developing child, but which has implications for children's experiences. Staff job satisfaction was focused on working with children and other adults, including parents and colleagues. Involvement with children was reported as being the most rewarding aspect of the work. This intrinsic satisfaction was enough to sustain caregivers' efforts to maintain their employment in child care programs. It was found that, while improving working conditions may help to reduce turnover, it is likely that moderate turnover rates will remain as child care staff work in relatively small centres and they leave in order to improve career prospects. Departure from a child care job appeared to be as much about improving career opportunities or changing personal circumstances, as it was about poor wages and working conditions. In the second study, factors that influence maternal satisfaction with child care arrangements were examined. The focus included examination of the nature and qualities of parental interaction with staff. This was a mesosystem analysis (Bronfenbrenner & Crouter, 1983), as it considered the links between family and child care settings. Two hundred and twenty-two questionnaires were returned from mothers whose children were enrolled in the participating centres. It was found that maternal satisfaction with child care encompassed the domains of child-centred and parent-centred satisfaction. The nature and range of responses in the quantitative and qualitative data indicated that these parents were genuinely satisfied with their children's care. In the prediction of maternal satisfaction with child care, single parents, mothers with high role satisfaction, and mothers who were satisfied with the frequency of staff contact and degree of supportive communication had higher levels of satisfaction with their child care arrangements. The third study described the structural and process variations within child care programs and examined program differences for compliance with regulations and differences by profit status of the centre, as a microsystem analysis (Bronfenbrenner, 1979). Observations were made in eighty-three programs which served children from two to five years. The results of the study affirmed beliefs that nonprofit centres are superior in the quality of care provided, although this was not to a level which meant that the care in for-profit centres was inadequate. Regulation of structural features of child care programs, per se, did not guarantee higher quality child care as measured by global or process indicators. The final study represented an integration of a range of influences in child care and family settings which may impact on development. Features of child care programs which predict children's social and cognitive development, while taking into account child and family characteristics, were identified. Results were consistent with other research findings which show that child and family characteristics and child care quality predict children's development. Child care quality was more important to the prediction of social development, while family factors appeared to be more predictive of cognitive/language development. An influential variable predictive of development was the period of time which the child had been in the centre. This highlighted the importance of the stability of child care arrangements. Child care quality features which had most influence were global ratings of the qualities of the program environment. However, results need to be interpreted cautiously as the explained variance in the predictive models developed was low. The results of these studies are discussed in terms of the implications for practice and future research. Considerations for an expanded view of ecological approaches to child care research are outlined. Issues discussed include the need to generate child care research which is relevant to social policy development, the implications of market driven policies for child care services, professionalism and professionalisation of child care work, and the need to reconceptualise child care research when the goal is to develop greater theoretical understanding about child care environments and developmental processes.

Single nucleotide polymorphism (SNP) - genotyping of Community Acquired Methicillin-Resistant Staphylococcus aureus, including the subtyping of PVL toxin producers using Real-Time PCR

Staphylococcus aureus is a common pathogen that causes a variety of infections including soft tissue infections, impetigo, septicemia toxic shock and scalded skin syndrome. Traditionally, Methicillin-Resistant Staphylococcus aureus (MRSA) was considered a Hospital-Acquired (HA) infection. It is now recognised that the frequency of infections with MRSA is increasing in the community, and that these infections are not originating from hospital environments. A 2007 report by the Centers for Disease Control and Prevention (CDC) stated that Staphylococcus aureus is the most important cause of serious and fatal infections in the USA. Community-Acquired MRSA (CA-MRSA) are genetically diverse and distinct, meaning they are able to be identified and tracked by way of genotyping. Genotyping of MRSA using Single nucleotide polymorphisms (SNPs) is a rapid and robust method for monitoring MRSA, specifically ST93 (Queensland Clone) dissemination in the community. It has been shown that a large proportion of CA-MRSA infections in Queensland and New South Wales are caused by ST93. The rationale for this project was that SNP analysis of MLST genes is a rapid and cost-effective method for genotyping and monitoring MRSA dissemination in the community. In this study, 16 different sequence types (ST) were identified with 41% of isolates identified as ST93 making it the predominate clone. Males and Females were infected equally with an average patient age of 45yrs. Phenotypically, all of the ST93 had an identical antimicrobial resistance pattern. They were resistant to the β-lactams – Penicillin, Flu(di)cloxacillin and Cephalothin but sensitive to all other antibiotics tested. Virulence factors play an important role in allowing S. aureus to cause disease by way of colonising, replication and damage to the host. One virulence factor of particular interest is the toxin Panton-Valentine leukocidin (PVL), which is composed of two separate proteins encoded by two adjacent genes. PVL positive CA-MRSA are shown to cause recurrent, chronic or severe skin and soft tissue infections. As a result, it is important that PVL positive CA-MRSA is genotyped and tracked. Especially now that CA-MRSA infections are more prevalent than HA-MRSA infections and are now deemed endemic in Australia. 98% of all isolates in this study tested positive for the PVL toxin gene. This study showed that PVL is present in many different community based ST, not just ST93, which were all PVL positive. With this toxin becoming entrenched in CA-MRSA, genotyping would provide more accurate data and a way of tracking the dissemination. PVL gene can be sub-typed using an allele-specific Real-Time PCR (RT-PCR) followed by High resolution meltanalysis. This allows the identification of PVL subtypes within the CA-MRSA population and allow the tracking of these clones in the community.

Identifying parents' perceptions about physical activity : a qualitative exploration of salient behavioural, normative and control beliefs among mothers and fathers of young children

Drawing on the belief-based framework of the Theory of Planned Behaviour, this study employs qualitative methodology involving individual and group interviews to examine the beliefs associated with regular physical activity performance among parents of young children (N = 40). The data were analysed using thematic content analysis. A range of advantages (e.g. improves parenting practices), disadvantages (e.g. interferes with commitments), barriers (e.g. time), and facilitators (e.g. social support) to performing physical activity are identified. Normative pressures are also identified as affecting parents’ activity behaviour. These identified beliefs can be used to inform interventions to challenge inactivity among this at-risk group.

Identifying key belief-based targets for promoting regular physical activity among mothers and fathers with young children

We investigated the key beliefs to target in interventions aimed at increasing physical activity (PA) among mothers and fathers of young children. Parents (288 mothers and 292 fathers) completed a Theory of Planned Behaviour belief-based questionnaire and a 1-week follow-up of PA behaviour. We found that a range of behavioural, normative, and control beliefs were significantly correlated with parents’ PA intentions and behaviour, with only a few differences observed in correlations between PA beliefs and intention and behaviour by gender. A range of key beliefs was identified as making independent contributions to parents’ PA intentions; however, the behavioural beliefs about improving parenting practices (β = 0.13), interfering with other commitments (β = −0.29); normative beliefs about people I exercise with (β = 0.20); and control beliefs about lack of time (β = −0.24), inconvenience (β = −0.14), lack of motivation (β = −0.34), were revealed as significant independent predictors of actual PA behaviour. Furthermore, we found that a limited amount of parents already hold these beliefs, suggesting that these key beliefs warrant changing and, therefore, are appropriate targets for subsequent intervention. The current study fills an empirical gap in the PA literature by investigating an at-risk group and using a well established theoretical framework to identify key beliefs that guide parents’ PA decision-making. Overall, we found support for parents being a unique group who hold distinctive behavioural, normative, and control beliefs toward PA. Attention to these key underlying beliefs will assist intervention work aimed at combating inactivity among this at-risk population.

Genotyping of enterococcus faecalis and enterococcus faecium isolates using a set of eight single nucleotide polymorphisms (SNPs)

A SNP genotyping method was developed for E. faecalis and E. faecium using the 'Minimum SNPs' program. SNP sets were interrogated using allele-specific real-time PCR. SNP-typing sub-divided clonal complexes 2 and 9 of E. faecalis and 17 of E. faecium, members of which cause the majority of nosocomial infections globally.

Lost children and imaginary mothers in Sonya Hartnett's Of A Boy

In Powers of Horror, Julia Kristeva writes about lost children. These are what she calls “dejects,” who, in the psychodrama of subject formation, fail to fully absent the body of the mother, to accept the Law of the Father and the Symbolic, and subsequently to establish “clear boundaries which constitute the object-world for normal subjects.” Dejects are “strays” looking for a place to belong, a place that is bound up with the Imaginary mother of the pre-Oedipal period. Kristeva’s sketch of the deject as one who is unable to negotiate a proper path to the Symbolicis useful to a reading of Hartnett’s Of A Boy (2002),a novel that also deals with lost children and imaginary mothers. However, in its portrayal of children who are doomed to never achieve adulthood, Of A Boy enacts a haunting retrieval of the pre-Oedipal from the dark side of phallocentric representation, privileging the semiotic (Kristeva’s concept) and the maternal as necessary disruptive checks on a patriarchal Symbolic Order.

Atomistic numerical investigation of single-crystal copper nanowire with surface defects

Based on the embedded atom method (EAM), a molecular dynamics (MD) simulation is performed to study the single-crystal copper nanowire with surface defects through tension. The tension simulations for nanowire without defect are first carried out under different temperatures, strain rates and time steps and then surface defect effects for nanowire are investigated. The stress-strain curves obtained by the MD simulations of various strain rates show a rate below 1 x 10(9) s-1 will exert less effect on the yield strength and yield point, and the Young's modulus is independent of strain rate. a time step below 5 fs is recommend for the atomic model during the MD simulation. It is observed that high temperature leads to low Young's modulus, as well as the yield strength. The surface defects on nanowires are systematically studied in considering different defect orientations. It is found that the surface defect serves as a dislocation source, and the yield strength shows 34.20% decresse with 45 degree surface defect. Both yield strength and yield point are significantly influenced by the surface defects, except the Young's modulus.

Predicting single-vehicle fatal crashes for two-lane rural highways in Southeastern United States

The rural two-lane highway in the southeastern United States is frequently associated with a disproportionate number of serious and fatal crashes and as such remains a focus of considerable safety research. The Georgia Department of Transportation spearheaded a regional fatal crash analysis to identify various safety performances of two-lane rural highways and to offer guidance for identifying suitable countermeasures with which to mitigate fatal crashes. The fatal crash data used in this study were compiled from Alabama, Georgia, Mississippi, and South Carolina. The database, developed for an earlier study, included 557 randomly selected fatal crashes from 1997 or 1998 or both (this varied by state). Each participating state identified the candidate crashes and performed physical or video site visits to construct crash databases with enhance site-specific information. Motivated by the hypothesis that single- and multiple-vehicle crashes arise from fundamentally different circumstances, the research team applied binary logit models to predict the probability that a fatal crash is a single-vehicle run-off-road fatal crash given roadway design characteristics, roadside environment features, and traffic conditions proximal to the crash site. A wide variety of factors appears to influence or be associated with single-vehicle fatal crashes. In a model transferability assessment, the authors determined that lane width, horizontal curvature, and ambient lighting are the only three significant variables that are consistent for single-vehicle run-off-road crashes for all study locations.

Multiple human single-stranded DNA binding proteins function in genome maintenance : structural, biochemical and functional analysis

DNA exists predominantly in a duplex form that is preserved via specific base pairing. This base pairing affords a considerable degree of protection against chemical or physical damage and preserves coding potential. However, there are many situations, e.g. during DNA damage and programmed cellular processes such as DNA replication and transcription, in which the DNA duplex is separated into two singlestranded DNA (ssDNA) strands. This ssDNA is vulnerable to attack by nucleases, binding by inappropriate proteins and chemical attack. It is very important to control the generation of ssDNA and protect it when it forms, and for this reason all cellular organisms and many viruses encode a ssDNA binding protein (SSB). All known SSBs use an oligosaccharide/oligonucleotide binding (OB)-fold domain for DNA binding. SSBs have multiple roles in binding and sequestering ssDNA, detecting DNA damage, stimulating strand-exchange proteins and helicases, and mediation of protein–protein interactions. Recently two additional human SSBs have been identified that are more closely related to bacterial and archaeal SSBs. Prior to this it was believed that replication protein A, RPA, was the only human equivalent of bacterial SSB. RPA is thought to be required for most aspects of DNA metabolism including DNA replication, recombination and repair. This review will discuss in further detail the biological pathways in which human SSBs function.

Physical and functional interaction of the archaeal single-stranded DNA-binding protein SSB with RNA polymerase

Archaeal transcription utilizes a complex multisubunit RNA polymerase and the basal transcription factors TBP and TF(II)B, closely resembling its eukaryal counterpart. We have uncovered a tight physical and functional interaction between RNA polymerase and the single-stranded DNA-binding protein SSB in Sulfolobus solfataricus. SSB stimulates transcription from promoters in vitro under TBP-limiting conditions and supports transcription in the absence of TBP. SSB also rescues transcription from repression by reconstituted chromatin. We demonstrate the potential for promoter melting by SSB, suggesting a plausible basis for the stimulation of transcription. This stimulation requires both the single-stranded DNA-binding domain and the acidic C-terminal tail of the SSB. The tail forms a stable interaction with RNA polymerase. These data reveal an unexpected role for single-stranded DNA-binding proteins in transcription in archaea.

Children of substance-using mothers : child health engagement and child protection outcomes

Aim: Maternal substance use has been associated with a range of child risk factors. The study investigated the relationship between engagement with child health services and child protection outcomes for children of substance using mothers. ----- ----- Methods: A sample of 119 children of mothers who disclosed opiate, amphetamine or methadone use during a maternity admission between 2000 and 2003, as included in a previous matched co-hort study1, were included in the current study. Statutory child protection agency and child health engagement information for the first two years of life, was obtained. The relationship between type of maternal substance use, child health engagement and child protection outcomes was examined. ----- ----- Results: Seventy two percent of study group infants were engaged with child health services during the first two years of life. Chi square analysis showed no significant relationship between child health engagement and child protection reports. Child health engagement was associated with decreased substantiated child protection notifications for children of methadone using mothers, but not for children of illicit substance users. ----- ----- Conclusions: Almost a quarter of identified children of substance using mothers are not accessing standard child health services in their first two years of life. This study provides support for increased attention to the provision of child health services for children of methadone using mothers. Further research into effective intervention strategies for children of illicit substance using mothers is indicated.

Single-stranded DNA-binding protein hSSB1 is critical for genomic stability

Single-strand DNA (ssDNA)-binding proteins (SSBs) are ubiquitous and essential for a wide variety of DNA metabolic processes, including DNA replication, recombination, DNA damage detection and repair1. SSBs have multiple roles in binding and sequestering ssDNA, detecting DNA damage, stimulating nucleases, helicases and strand-exchange proteins, activating transcription and mediating protein–protein interactions. In eukaryotes, the major SSB, replication protein A (RPA), is a heterotrimer1. Here we describe a second human SSB (hSSB1), with a domain organization closer to the archaeal SSB than to RPA. Ataxia telangiectasia mutated (ATM) kinase phosphorylates hSSB1 in response to DNA double-strand breaks (DSBs). This phosphorylation event is required for DNA damage-induced stabilization of hSSB1. Upon induction of DNA damage, hSSB1 accumulates in the nucleus and forms distinct foci independent of cell-cycle phase. These foci co-localize with other known repair proteins. In contrast to RPA, hSSB1 does not localize to replication foci in S-phase cells and hSSB1 deficiency does not influence S-phase progression. Depletion of hSSB1 abrogates the cellular response to DSBs, including activation of ATM and phosphorylation of ATM targets after ionizing radiation. Cells deficient in hSSB1 exhibit increased radiosensitivity, defective checkpoint activation and enhanced genomic instability coupled with a diminished capacity for DNA repair. These findings establish that hSSB1 influences diverse endpoints in the cellular DNA damage response.

Highly discriminatory single-nucleotide polymorphism interrogation of Escherichia coli by use of allele-specific real-time PCR and eBURST analysis

In total, 782 Escherichia coli strains originating from various host sources have been analyzed in this study by using a highly discriminatory single-nucleotide polymorphism (SNP) approach. A set of eight SNPs, with a discrimination value (Simpson's index of diversity [D]) of 0.96, was determined using the Minimum SNPs software, based on sequences of housekeeping genes from the E. coli multilocus sequence typing (MLST) database. Allele-specific real-time PCR was used to screen 114 E. coli isolates from various fecal sources in Southeast Queensland (SEQ). The combined analysis of both the MLST database and SEQ E. coli isolates using eight high-D SNPs resolved the isolates into 74 SNP profiles. The data obtained suggest that SNP typing is a promising approach for the discrimination of host-specific groups and allows for the identification of human-specific E. coli in environmental samples. However, a more diverse E. coli collection is required to determine animal- and environment-specific E. coli SNP profiles due to the abundance of human E. coli strains (56%) in the MLST database.