970 resultados para Field evidence


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There is growing regulatory pressure on firms worldwide to address the under-representation of women in senior positions. Regulators have taken a variety of approaches to the issue. We investigate a jurisdiction that has issued recommendations and disclosure requirements, rather than implementing quotas. Much of the rhetoric surrounding gender diversity centres on whether diversity has a financial impact. In this paper we take an aggregate (market-level) approach and compare the performance of portfolios of firms with gender diverse boards to those without. We also investigate whether having multiple women on the board is linked to performance, and if there is a within-industry effect. Overall, we do not find evidence of an association between diversity and performance. We find some weak evidence of a negative correlation between having multiple women on the board and performance, but that in some industries diversity is positively correlated with performance.

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Instances of parallel ecotypic divergence where adaptation to similar conditions repeatedly cause similar phenotypic changes in closely related organisms are useful for studying the role of ecological selection in speciation. Here we used a combination of traditional and next generation genotyping techniques to test for the parallel divergence of plants from the Senecio lautus complex, a phenotypically variable groundsel that has adapted to disparate environments in the South Pacific. Phylogenetic analysis of a broad selection of Senecio species showed that members of the S. lautus complex form a distinct lineage that has diversified recently in Australasia. An inspection of thousands of polymorphisms in the genome of 27 natural populations from the S. lautus complex in Australia revealed a signal of strong genetic structure independent of habitat and phenotype. Additionally, genetic differentiation between populations was correlated with the geographical distance separating them, and the genetic diversity of populations strongly depended on geographical location. Importantly, coastal forms appeared in several independent phylogenetic clades, a pattern that is consistent with the parallel evolution of these forms. Analyses of the patterns of genomic differentiation between populations further revealed that adjacent populations displayed greater genomic heterogeneity than allopatric populations and are differentiated according to variation in soil composition. These results are consistent with a process of parallel ecotypic divergence in face of gene flow.

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This study is an inquiry into early childhood teacher professional identities. In Australia, workforce reforms in early childhood include major shifts in qualification requirements that call for a university four-year degree-qualified teacher to be employed in child care. This marks a shift in the early years workforce, where previously there was no such requirement. At the same time as these reforms to quality measures are being implemented, and requiring a substantive up skilling of the workforce, there is a growing body of evidence through recent studies that suggests these same four-year degree-qualified early childhood teachers have an aversion to working in child care. Their preferred employment option is to work in the early years of more formal schooling, not in before-school contexts. This collision of agendas warrants investigation. This inquiry is designed to investigate the site at which advocacy for higher qualification requirements meets early childhood teachers who are reluctant to choose child care as a possible career pathway. The key research question for this study is: How are early childhood teachers’ professional identities currently produced? The work of this thesis is to problematise the early childhood teacher in child care through a particular method of discourse analysis. There are two sets of data. The first was a key early childhood political document that read as a "moment of arising" (Foucault, 1984a, p. 83). It is a political document which was selected for its current influence on the early childhood field, and in particular, workforce reforms that call for four-year degree-qualified teachers to work in before-school contexts, including child care. The second data set was generated through four focus group discussions conducted with preservice early childhood teachers. The document and transcripts of the focus groups were both analysed as text, as conceptualised by Foucault (1981). Foucault’s work spans a number of years and a range of philosophical matters. This thesis draws particularly on Foucault’s writings on discourse, power/knowledge, regimes of truth and resistance. In order to consider the production of early childhood teachers’ professional identities, the study is also informed by identity theorists, who have worked on gender, performativity and investment (Davies, 2004/2006; McNay, 1992; Osgood, 2012; Walkerdine, 1990; Weedon, 1997). The ways in which discourses intersect, compete and collide produce the subject (Foucault, 1981) and, in the case of this inquiry, there are a number of competing discourses at play, which produce the early childhood teacher. These particular theories turn particular lenses on the question of professional identities in early childhood, and such a study calls for the application of particular methodologies. Discourse analysis was used as the methodological framework, and the analysis was informed by Foucauldian concepts of discourse. While Foucault did not prescribe a form of discourse analysis as a method, his writings nonetheless provide a valuable framework for illuminating discursive practices and, in turn, how people are affected, through the shifts and distribution of power (Foucault, 1980a). The treatment used with both data sets involved redescription. For the policy document, a technique for reading document-as-text applied a genealogical approach (Foucault, 1984a). For the focus groups, the process of redescription (Rorty, 1989) involved reading talk-as-text. As a method, redescription involves describing "lots and lots of things in new ways until you have created a pattern of linguistic behaviour which will tempt the new generation to adopt it" (Rorty, 1989, p. 9). The development and application of categories (Davies, 2004/2006) built on a poststructuralist theoretical framework and the literature review informed the data analysis method of discourse analysis. Irony provided a rhetorical and playful tool (Haraway, 1991; Rorty, 1989), to look to how seemingly opposing discourses are held together. This opens a space to collapse binary thinking and consider seemingly contradictory terms in a way in which both terms are possible and both are true. Irony resists the choice of one or the other being right, and holds the opposites together in tension. The thesis concludes with proposals for new, ironic categories, which work to bring together seemingly opposing terms, located at sites in the field of early childhood where discourses compete, collide and intersect to produce and maintain early childhood teacher professional identities. The process of mapping these discourses goes some way to investigating the complexities about identities and career choices of early childhood teachers. The category of "the cost of loving" captures the collision between care/love, inherent in child care, and new discourses of investment/economics. Investment/economics has not completely replaced care/love, and these apparent opposites were not read as a binary because both are necessary and both are true (Haraway, 1991). They are held together in tension to produce early childhood teacher professional identities. The policy document under scrutiny was New Directions, released in 2007 by the then opposition ALP leader, Kevin Rudd. The claim was made strongly that the "economic prosperity" of Australia relies on investment in early childhood. The arguments to invest are compelling and the neuroscience/brain research/child development together with economic/investment discourses demand that early childhood is funding is increased. The intersection of these discourses produces professional identities of early childhood teachers as a necessary part of the country’s economy, and thus, worthy of high status. The child care sector and work in child care settings are necessary, with children and the early childhood teacher playing key roles in the economy of the nation. Through New Directions it becomes sayable (Foucault, 1972/1989) that the work the early childhood teacher performs is legitimated and valued. The children are produced as "economic units". A focus on what children are able to contribute to the future economy of the nation re-positions children and produces these "smart productive citizens", making future economic contribution. The early childhood teacher is produced through this image of a child and "the cost of loving" is emphasised. A number of these categories were produced through the readings of the document-as text and the talk-as-text. Two ironic categories were read in the analysis of the transcripts of the focus group discussions, when treated as talk-as-text data: the early childhood teacher as a "heroic victim"; and the early childhood teacher as a "glorified babysitter". This thesis raises new questions about professional identities in early childhood. These new questions might go some way to prompt re-thinking of some government policy, as well as some aspects of early childhood teacher education course design. The images of children and images of child care provide provocations to consider preservice teacher education course design. In particular, how child care, as one of the early childhood contexts, is located, conceptualised and spoken throughout the course. Consideration by course designers and teacher educators of what discourses are privileged in course content —what discourses are diminished or silenced—would go some way to reconceptualising child care within preservice teacher education and challenging dominant ways of speaking child care, and work in child care. This inquiry into early childhood teachers’ professional identities has gone some way to exploring the complexities around the early childhood teacher in child care. It is anticipated that the significance of this study will thus have immediate applicably and relevance for the Australian early childhood policy landscape. The early childhood field is in a state of rapid change, and this inquiry has examined some of the disconnects between policy and practice. Awareness of the discourses that are in play in the field will continue to allow space for conversations that challenge dominant assumptions about child care, work in child care and ways of being an early childhood teacher in child care.

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Multiple sclerosis (MS) is a common chronic inflammatory disease of the central nervous system. Susceptibility to the disease is affected by both environmental and genetic factors. Genetic factors include haplotypes in the histocompatibility complex (MHC) and over 50 non-MHC loci reported by genome-wide association studies. Amongst these, we previously reported polymorphisms in chromosome 12q13-14 with a protective effect in individuals of European descent. This locus spans 288 kb and contains 17 genes, including several candidate genes which have potentially significant pathogenic and therapeutic implications. In this study, we aimed to fine-map this locus. We have implemented a two-phase study: a variant discovery phase where we have used next-generation sequencing and two target-enrichment strategies [long-range polymerase chain reaction (PCR) and Nimblegen's solution phase hybridization capture] in pools of 25 samples; and a genotyping phase where we genotyped 712 variants in 3577 healthy controls and 3269 MS patients. This study confirmed the association (rs2069502, P = 9.9 × 10−11, OR = 0.787) and narrowed down the locus of association to an 86.5 kb region. Although the study was unable to pinpoint the key-associated variant, we have identified a 42 (genotyped and imputed) single-nucleotide polymorphism haplotype block likely to harbour the causal variant. No evidence of association at previously reported low-frequency variants in CYP27B1 was observed. As part of the study we compared variant discovery performance using two target-enrichment strategies. We concluded that our pools enriched with Nimblegen's solution phase hybridization capture had better sensitivity to detect true variants than the pools enriched with long-range PCR, whilst specificity was better in the long-range PCR-enriched pools compared with solution phase hybridization capture enriched pools; this result has important implications for the design of future fine-mapping studies.

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Migraine is a common and debilitating neurovascular disorder with a complex envirogenomic aetiology. Numerous studies have demonstrated a preponderance of women affected with migraine and previous pedigree linkage studies in our laboratory have identified susceptibility loci on chromosome Xq24-Xq28. In this study we have used the genetic isolate of Norfolk Island to further analyse the X chromosome for migraine susceptibility loci. An association approach was employed to analyse 14,124 SNPs spanning the entire X chromosome. Genotype data from 288 individuals comprising a large core-pedigree, of which 76 were affected with migraine, were analysed. Although no SNP reached chromosome-wide significance (empirical α = 1×10−5) ranking by P-value revealed two primary clusters of SNPs in the top 25. A 10 SNP cluster represents a novel migraine susceptibility locus at Xq12 whilst a 11 SNP cluster represents a previously identified migraine susceptibility locus at Xq27. The strongest association at Xq12 was seen for rs599958 (OR = 1.75, P = 8.92×10−4), whilst at Xq27 the strongest association was for rs6525667 (OR = 1.53, P = 1.65×10−4). Further analysis of SNPs at these loci was performed in 5,122 migraineurs from the Women’s Genome Health Study and provided additional evidence for association at the novel Xq12 locus (P<0.05). Overall, this study provides evidence for a novel migraine susceptibility locus on Xq12. The strongest effect SNP (rs102834, joint P = 1.63×10−5) is located within the 5′UTR of the HEPH gene, which is involved in iron homeostasis in the brain and may represent a novel pathway for involvement in migraine pathogenesis.

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Australia has continued to benefit from the human, social and economic capital contributed by immigrant resettlement over many years. Humanitarian entrants have also made significant economic, social and civic contributions to the Australian society. Since 2000, approximately 160,000 people have entered Australia under the refugee and humanitarian resettlement program; around 15% have come from South Sudan and one third of these are adult males. In response to the 2003 evaluation of the Integrated Humanitarian Settlement Strategy (IHSS), which recommended to seek further opportunities to settle humanitarian entrants in regional Australia, the Department of Immigration and Citizenship (DIAC) has since encouraged regional settlement to “address the demand for less skilled labour in regional economies and to assist humanitarian entrants to achieve early employment”. There is evidence, however, of the many challenges faced by humanitarian arrivals living in regional areas. This chapter focuses on the educational and occupational outcomes among 117 South Sudanese adult men from refugee backgrounds. In particular, the chapter uses both cross-sectional (at first interview) and longitudinal data (four interviews with each participant at six-month intervals) to compares outcomes between men living in Brisbane and those living in the Toowoomba–Gatton region in Southeast Queensland.

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Interpreting the unexplained component of the gender wage gap as indicative of discrimination, the empirical literature to date has tended to ignore the potential impact wage discrimination may have on employment. Employment effects may arise if discrimination lowers the female offered wage and the labour supply curve is upward sloping. The empirical analysis employs the British Household Panel Study and finds evidence of both wage and associated employment effects.

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The empirical analysis employs individual level data from the Australian Health Survey combined with retrospective data on tobacco price matched to the age at which the individual started and quit smoking. Split-population hazard models are estimated for both starting and quitting smoking. The analysis suggests price plays a significant role in the decision to start smoking but not in the decision to quit. Further sensitivity analysis of different age groups and an alternative data source, questions the robustness of the significant role of price in the smoking initiation decision. From a policy perspective, the results indicate that increases in tobacco taxation can be an important instrument in reducing the incidence of smoking, but should be combined with other mechanisms such as mandating smoke-free environments and antismoking education. Our results strongly support the targeting of antismoking campaigns towards teenagers.

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Migraine is considered to be a multifactorial disorder in which genetic, environmental, and, in the case of menstrual and menstrually related migraine, hormonal events influence the phenotype. Certainly, the role of female sex hormones in migraine has been well established, yet the mechanism behind this well-known relationship remains unclear. This review focuses on the potential role of hormonally related genes in migraine, summarizes results of candidate gene studies to date, and discusses challenges and issues involved in interpreting hormone-related gene results. In light of the molecular evidence presented, we discuss future approaches for analysis with the view to elucidate the complex genetic architecture that underlies the disorder.

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Recent association studies in multiple sclerosis (MS) have identified and replicated several single nucleotide polymorphism (SNP) susceptibility loci including CLEC16A, IL2RA, IL7R, RPL5, CD58, CD40 and chromosome 12q13–14 in addition to the well established allele HLA-DR15. There is potential that these genetic susceptibility factors could also modulate MS disease severity, as demonstrated previously for the MS risk allele HLA-DR15. We investigated this hypothesis in a cohort of 1006 well characterised MS patients from South-Eastern Australia. We tested the MS-associated SNPs for association with five measures of disease severity incorporating disability, age of onset, cognition and brain atrophy. We observed trends towards association between the RPL5 risk SNP and time between first demyelinating event and relapse, and between the CD40 risk SNP and symbol digit test score. No associations were significant after correction for multiple testing. We found no evidence for the hypothesis that these new MS disease risk-associated SNPs influence disease severity.

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Bactrocera dorsalis (Hendel), Bactrocera papayae Drew & Hancock, Bactrocera philippinensis Drew & Hancock, and Bactrocera carambolae Drew & Hancock are pest members within the B. dorsalis species complex of tropical fruit flies. The species status of these taxa is unclear and this confounds quarantine, pest management, and general research. Mating studies carried out under uniform experimental conditions are required as part of resolving their species limits. These four taxa were collected from the wild and established as laboratory cultures for which we subsequently determined levels of prezygotic compatibility, assessed by field cage mating trials for all pair-wise combinations. We demonstrate random mating among all pair-wise combinations involving B. dorsalis, B. papayae, and B. philippinensis. B. carambolae was relatively incompatible with each of these species as evidenced by nonrandom mating for all crosses. Reasons for incompatibility involving B. carambolae remain unclear; however, we observed differences in the location of couples in the field cage for some comparisons. Alongside other factors such as pheromone composition or other courtship signals, this may lead to reduced interspecific mating compatibility with B. carambolae. These data add to evidence that B. dorsalis, B. papayae, and B. philippinensis represent the same biological species, while B. carambolae remains sufficiently different to maintain its current taxonomic identity. This poses significant implications for this group's systematics, impacting on pest management, and international trade.

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Migraine is a prevalent neurovascular disease with a significant genetic component. Linkage studies have so far identified migraine susceptibility loci on chromosomes 1, 4, 6, 11, 14, 19 and X. We performed a genome-wide scan of 92 Australian pedigrees phenotyped for migraine with and without aura and for a more heritable form of “severe” migraine. Multipoint non-parametric linkage analysis revealed suggestive linkage on chromosome 18p11 for the severe migraine phenotype (LOD*=2.32, P=0.0006) and chromosome 3q (LOD*=2.28, P=0.0006). Excess allele sharing was also observed at multiple different chromosomal regions, some of which overlap with, or are directly adjacent to, previously implicated migraine susceptibility regions. We have provided evidence for two loci involved in severe migraine susceptibility and conclude that dissection of the “migraine” phenotype may be helpful for identifying susceptibility genes that influence the more heritable clinical (symptom) profiles in affected pedigrees. Also, we concluded that the genetic aetiology of the common (International Headache Society) forms of the disease is probably comprised of a number of low to moderate effect susceptibility genes, perhaps acting synergistically, and this effect is not easily detected by traditional single-locus linkage analyses of large samples of affected pedigrees.

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Migraine is a common complex disorder that shows strong familial aggregation. There is a general increased prevalence of migraine in females compared with males, with recent studies indicating that migraine affects 18% of females compared with 6% of males. This preponderance of females among migraine sufferers coupled with evidence of an increased risk of migraine in first degree relatives of male probands but not in relatives of female probands suggests the possibility of an X-linked dominant gene. We report here the localization of a typical migraine susceptibility locus to the X chromosome. Of three large multigenerational migraine pedigrees two families showed significant excess allele sharing to Xq markers (P = 0.031 and P = 0.012). Overall analysis of data from all three pedigrees gave significant evidence in support of linkage and heterogeneity (HLOD = 3.1). These findings provide conclusive evidence that familial typical migraine is a heterogeneous disorder. We suggest that the localization of a migraine susceptibility locus to the X chromosome could in part explain the increased risk of migraine in relatives of male probands and may be involved in the increased female prevalence of this disorder.

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The appearance of Plasmodium falciparum parasites with decreased in vivo sensitivity but no measurable in vitro resistance to artemisinin has raised the urgent need to characterize the artemisinin resistance phenotype. Changes in the temporary growth arrest (dormancy) profile of parasites may be one aspect of this phenotype. In this study, we investigated the link between dormancy and resistance, using artelinic acid (AL)-resistant parasites. Our results demonstrate that the AL resistance phenotype has (i) decreased sensitivity of mature-stage parasites, (ii) decreased sensitivity of the ring stage to the induction of dormancy, and (iii) a faster recovery from dormancy.

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Charcot-Marie-Tooth neuropathy type 1 (CMT1) is an autosomal dominant disorder originally localized to chromosome 1 by linkage to the Duffy blood group. Studies have since shown that the disorder may be heterogeneous, as not all families show this linkage. We tested genetic heterogeneity by the HOMOG computer program in 15 CMT1 pedigrees informative for Duffy. We detected no evidence for heterogeneity in this sample, but when we combined results with previously published lod scores, heterogeneity was statistically significant. Twelve of the 15 families studied did not show linkage to Duffy. We found six of these families to be informative for a chromosome 19 marker, apolipoprotein CII(ApoC2). Despite a previous report showing probable linkage of a non-Duffy-linked CMT1 pedigree to two chromosome 19 markers, we did not detect significant linkage of ApoC2 to CMT1 in these families.