605 resultados para Susan Tierney
Resumo:
We investigated the relationship between mitochondrial biogenesis, cell signalling and antioxidant enzymes by depleting skeletal muscle glutathione with diethyl maleate (DEM) which resulted in a demonstrable increase in oxidative stress during exercise. Animals were divided into six groups: (1) sedentary control rats; (2) sedentary rats treated with DEM; (3) exercise control rats euthanized immediately after exercise; (4) exercise rats + DEM; (5) exercise control rats euthanized 4 h after exercise, and; (6) exercise rats + DEM euthanized 4 h after exercise. Exercising animals ran on the treadmill at a 10% gradient at 20 m/min for the first 30 min. The speed was then increased every 10 min by 1.6 m/min until exhaustion. There was a reduction in total glutathione in the skeletal muscle of DEM treated animals compared to the control animals (P<0.05). Within the control group, total glutathione was higher in the sedentary group compared to after exercise (P<0.05). DEM treatment also significantly increased oxidative stress, as measured by increased plasma F2-isoprostanes (P<0.05). Exercising animals given DEM showed a significantly greater increase in peroxisome proliferator activated receptor γ coactivator-1α(PGC-1α) mRNA compared to the control animals that were exercised (P<0.05). This study provides novel evidence that by reducing the endogenous antioxidant glutathione in skeletal muscle and inducing oxidative stress through exercise, PGC-1α gene expression was augmented. These findings further highlight the important role of exercise induced oxidative stress in the regulation of mitochondrial biogenesis.
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Water education and conservation programs have grown exponentially in Australian primary and secondary schools and, although early childhood services have been slower to respond to the challenges of sustainability, they are catching up fast. One early program targeted at preschools was the Water Aware Centre Program in northern New South Wales developed by the local water supply authority. This paper reports on a qualitative study of children’s and teachers’ experiences of the program in three preschools. The study’s aim was to identify program attributes and pedagogies that supported learning and action taking for water conservation, and to investigate if and how the program influenced children’s and teachers’practices. Data were collected through an interview with the program designer, conversations with child participants of the program, and a qualitative survey with early childhood staff. A three-step thematic analysis was conducted on the children’s and teachers’ data. Findings revealed that the program expanded children and teachers’ ideas about water conservation and increased their water conservation practices. The children were found to influence the water conservation practices of the adults around them, thus changing practices at school and at home.
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Three families of probe-foraging birds, Scolopacidae (sandpipers and snipes), Apterygidae (kiwi), and Threskiornithidae (ibises, including spoonbills) have independently evolved long, narrow bills containing clusters of vibration-sensitive mechanoreceptors (Herbst corpuscles) within pits in the bill-tip. These ‘bill-tip organs’ allow birds to detect buried or submerged prey via substrate-borne vibrations and/or interstitial pressure gradients. Shorebirds, kiwi and ibises are only distantly related, with the phylogenetic divide between kiwi and the other two taxa being particularly deep. We compared the bill-tip structure and associated somatosensory regions in the brains of kiwi and shorebirds to understand the degree of convergence of these systems between the two taxa. For comparison, we also included data from other taxa including waterfowl (Anatidae) and parrots (Psittaculidae and Cacatuidae), non-apterygid ratites, and other probe-foraging and non probe-foraging birds including non-scolopacid shorebirds (Charadriidae, Haematopodidae, Recurvirostridae and Sternidae). We show that the bill-tip organ structure was broadly similar between the Apterygidae and Scolopacidae, however some inter-specific variation was found in the number, shape and orientation of sensory pits between the two groups. Kiwi, scolopacid shorebirds, waterfowl and parrots all shared hypertrophy or near-hypertrophy of the principal sensory trigeminal nucleus. Hypertrophy of the nucleus basorostralis, however, occurred only in waterfowl, kiwi, three of the scolopacid species examined and a species of oystercatcher (Charadriiformes: Haematopodidae). Hypertrophy of the principal sensory trigeminal nucleus in kiwi, Scolopacidae, and other tactile specialists appears to have co-evolved alongside bill-tip specializations, whereas hypertrophy of nucleus basorostralis may be influenced to a greater extent by other sensory inputs. We suggest that similarities between kiwi and scolopacid bill-tip organs and associated somatosensory brain regions are likely a result of similar ecological selective pressures, with inter-specific variations reflecting finer-scale niche differentiation.
Resumo:
The water mouse, Xeromys myoides, is currently recognised as a vulnerable species in Australia, inhabiting a small number of distinct and isolated coastal regions of Queensland and the Northern Territory. An examination of the evolutionary history and contemporary influences shaping the genetic structure of this species is required to make informed conservation management decisions. Here, we report the first analysis undertaken on the phylogeography and population genetics of the water mouse across its mainland Australian distribution. Genetic diversity was assessed at two mitochondrial DNA (Cytochrome b, 1000 bp; D-loop, 400 bp) and eight microsatellite DNA loci. Very low genetic diversity was found, indicating that water mice underwent a recent expansion throughout their Australian range and constitute a single evolutionarily significant unit. Microsatellite analyses revealed that the highest genetic diversity was found in the Mackay region of central Queensland; population substructure was also identified, suggesting that local populations may be isolated in this region. Conversely, genetic diversity in the Coomera region of south-east Queensland was very low and the population in this region has experienced a significant genetic bottleneck. These results have significant implications for future management, particularly in terms of augmenting populations through translocations or reintroducing water mice in areas where they have gone extinct.
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Smaller firms are often viewed as resistant to regulation due to cost burdens. However, evidence indicates that for some compliance is beneficial under certain conditions. Drawing on data on attitudes and responses of smaller firm owner-managers to changes in Australia’s harmonising work health and safety context we report on smaller firms’ responses to these changes. Despite uncertainty due to incomplete harmonisation, many owner-managers viewed safety compliance as important and necessary to do business. Those with negative views still linked positive safety performance to business outcomes. We categorise smaller firms’ responses and in this sample most are Positive Responders. We suggest ways forward for policy-makers to support smaller firms in complying with occupational health and safety regulation.
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Using established strategic management and business model frameworks we map the evolution of universities in the context of their value proposition to students as consumers of their products. We argue that in the main universities over time have transitioned from a value-based business model through to an efficiency-based business model that for numerous reasons, is becoming rapidly unsustainable. We further argue that the future university business models would benefit with a reconfiguration towards a network value based model. This approach requires a revised set of perceived benefits, better aligned to the current and future expectations and an alternate approach to the delivery of those benefits to learner / consumers.
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Corner detection has shown its great importance in many computer vision tasks. However, in real-world applications, noise in the image strongly affects the performance of corner detectors. Few corner detectors have been designed to be robust to heavy noise by now, partly because the noise could be reduced by a denoising procedure. In this paper, we present a corner detector that could find discriminative corners in images contaminated by noise of different levels, without any denoising procedure. Candidate corners (i.e., features) are firstly detected by a modified SUSAN approach, and then false corners in noise are rejected based on their local characteristics. Features in flat regions are removed based on their intensity centroid, and features on edge structures are removed using the Harris response. The detector is self-adaptive to noise since the image signal-to-noise ratio (SNR) is automatically estimated to choose an appropriate threshold for refining features. Experimental results show that our detector has better performance at locating discriminative corners in images with strong noise than other widely used corner or keypoint detectors.
Resumo:
The chapter contributes understandings of digitally mediated interactions in early childhood classrooms. Ethnomethodological and conversation analysis approaches are used to analyse a video-recorded episode of children and teacher composing an email in a preschool classroom. In their talk we find how the teacher directs the children to what counts procedurally, such as the components of an email, and the teacher’s moral work in producing a culturally correct way form of personal communication. Such considerations of situated examples can encourage investigations of digital practices that extend beyond operational skills to broader understandings of digital practices as cultural and situated activities.
Resumo:
This article begins with the premise that morality is an intrinsic, although often invisible, aspect of everyday social action. Drawn from a corpus of fifty audiorecorded telephone calls to Kids Helpline, an Australian helpline for children and young people, we examine one call to show how the young caller and counsellor co-construct ‘morality-in-action’. Ethnomethodological understandings and, in particular, Sacks’ (1992) description of ‘Class 2’ rules and infractions show how an adolescent caller and counsellor collaboratively assemble moral versions of the caller. In puzzling out possible motives, the caller and counsellor can be seen to be attending to the implications of different moral versions of the caller. This attribution of motives is moral work in action, with motives contingently assembled, displayed and evaluated, with such work understood as displays of moral reasoning. The counselling call makes visible the counsellor’s interactional work to support and empower the client. Analysis such as this offers counsellors ways of understanding and making visible their interactional and moral work within helpline call interactions.
Resumo:
New digital media surrounds us. Little is known, however, about the influence of technology devices such as tablets (e.g. iPads) and smart phones on young children’s lives in home and school settings, and what it means for them throughout their schooling and beyond. Most research to date has focused on children aged six years and older, and much less (with a few exceptions) on preschool-aged children. This article draws on parent interviews to show how family members engage with technology as part of the flow of everyday life. Only time and increased understandings of everyday practices will tell the real values and scope of using digital media.
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This chapter investigates counselling interactions where young clients talk about their experiences of taking on family responsibilities normatively associated with parental roles. In research counselling literature, practices where relationships in families operate so that there is a reversal of roles, with children managing the households and caring for parents and siblings, is described as parentification. Parentification is used in the counselling literature as a clinician/researcher term, which we ‘respecify’ (Garfinkel, 1991) the tem by beginning with an investigation of young clients’ own accounts of being an adult or parent and how counsellors orient to these accounts. As well as providing understandings of how young people propose accounts of their experiences of adult-child role reversal, the chapter contributes to understanding how children and young people use the resources of counselling helplines, and how counselors can communicate effectively with children and young people.
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This chapter provides a theoretical overview of literature that uses conversation analysis (CA) to explore children’s interactions related to trauma and associated mental health matters. The relatively new approach of using CA to understand trauma reveals the importance of talk in the process of recovery, and also how the participants co-construct talk about traumatic experiences. The chapter will explore literature using a CA approach to investigate children’s trauma talk with professionals as well as literature specifically discussing children’s talk about their traumatic experiences with people who are not qualified therapists or psychiatrists. We conclude by calling for more research using a CA approach for investigating children’s traumatic experiences due to the insight it provides into each child’s personal sense making of traumatic events with a range of people.
Resumo:
Rendle-Short, Wilkinson, and Danby show how social interaction is directly relevant to maintaining friendships, mental health and well-being, and supportive peer relations. Using conversation analysis, the chapter focuses on conversational participants’ pursuit of affiliation and intimacy from a language as action perspective. It focuses on the use of derogatory naming practices by a 10-year-old girl diagnosed with Asperger’s Syndrome. The analysis shows how derogatory address terms, part of a wider pattern of behaviour evident in this child’s interaction, result in behaviour that might be thought of as impolite or lacking in restraint. It also illustrates how a single case study can draw attention to the context-specific nature of interaction when working with children with Asperger’s Syndrome. The chapter contributes to our understanding of the difficulty in pinpointing, with precision and with clear evidence, what counts as a ‘social interaction difficulty’ due to the context specific nature of interaction.
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Aim To examine whether pre-pregnancy weight status was associated with maternal feeding beliefs and practices in the early post-partum period. Methods Secondary analysis of longitudinal data from Australian mothers. Participants (N=486) were divided into two weight status groups based on self-reported pre-pregnancy weight and measured height: healthy weight (BMI <25kg/m2; n=321) and overweight (BMI>25kg/m2; n=165). Feeding beliefs and practices were self-reported via an established questionnaire that assessed concerns about infant overeating and undereating, awareness of infant cues, feeding to a schedule, and using food to calm. Results Infants of overweight mothers were more likely to have been given solid foods in the previous 24hrs (29% vs 20%) and fewer were fully breastfed (50% vs 64%). Multivariable regression analyses (adjusted for maternal education, parity, average infant weekly weight gain, feeding mode and introduction of solids) revealed pre-pregnancy weight status was not associated with using food to calm, concern about undereating, awareness of infant cues or feeding to a schedule. However feeding mode was associated with feeding beliefs and practices. Conclusions Although no evidence for a relationship between maternal weight status and early maternal feeding beliefs and practices was observed, differences in feeding mode and early introduction of solids was observed. The emergence of a relationship between feeding practices and maternal weight status may occur when the children are older, solid feeding is established and they become more independent in feeding.