979 resultados para Stephen Abram
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Social media adoption in Australia, which provides the geographic focus for this chapter, has been rapid and substantial (ABC News, 2010) – possibly because of the considerable dispersal of the Australian population across the continent, as well as the significant distance of the country from many of its closest partner nations. Social media can play an important role in strengthening and maintaining interpersonal and professional relationships in spite of such physical distance; in particular, social media services are now well-recognised as important tools for the dissemination of news across many developed nations. Hermida (2010) and Burns (2010) both speak of Twitter as a medium for “ambient news”, for example: always-on, operating as a steady stream in the background and at the edge of users’ conscious perception. Much as ambient music is designed to do, it comes to the fore when notable events (such as major breaking news) lead to an increase in volume and demand a greater level of attention from users.
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Recent evidence indicates that the estrogen receptor-a-negative, androgen receptor (AR)- positive molecular apocrine subtype of breast cancer is driven by AR signaling. The MDA-MB-453 cell line is the prototypical model of this breast cancer subtype; its proliferation is stimulated by androgens such as 5a-dihydrotestosterone (DHT) but inhibited by the progestin medroxyprogesterone acetate (MPA) via AR-mediated mechanisms. We report here that the AR gene in MDAMB- 453 cells contains a G-T transversion in exon 7, resulting in a receptor variant with a glutamine to histidine substitution at amino acid 865 (Q865H) in the ligand binding domain. Compared with wild-type AR, the Q865H variant exhibited reduced sensitivity to DHT and MPA in transactivation assays in MDA-MB-453 and PC-3 cells but did not respond to non-androgenic ligands or receptor antagonists. Ligand binding, molecular modeling, mammalian two-hybrid and immunoblot assays revealed effects of the Q865H mutation on ligand dissociation, AR intramolecular interactions, and receptor stability. Microarray expression profiling demonstrated that DHT and MPA regulate distinct transcriptional programs in MDA-MB-453 cells. Gene Set Enrichment Analysis revealed that DHT- but not MPA-regulated genes were associated with estrogen-responsive transcriptomes from MCF-7 cells and the Wnt signaling pathway. These findings suggest that the divergent proliferative responses of MDA-MB-453 cells to DHT and MPA result from the different genetic programs elicited by these two ligands through the AR-Q865H variant. This work highlights the necessity to characterize additional models of molecular apocrine breast cancer to determine the precise role of AR signaling in this breast cancer subtype. Endocrine-Related Cancer (2012) 19 599–613
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This paper introduces a parallel implementation of an agent-based model applied to electricity distribution grids. A fine-grained shared memory parallel implementation is presented, detailing the way the agents are grouped and executed on a multi-threaded machine, as well as the way the model is built (in a composable manner) which is an aid to the parallelisation. Current results show a medium level speedup of 2.6, but improvements are expected by incor-porating newer distributed or parallel ABM schedulers into this implementa-tion. While domain-specific, this parallel algorithm can be applied to similarly structured ABMs (directed acyclic graphs).
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Background Several lines of evidence suggests that transcription factors are involved in the pathogenesis of Multiple Sclerosis (MS) but a complete mapping the whole network has been elusive. One of the reasons is that there are several clinical subtypes of MS and transcription factors which may be involved in one subtype may not be in others. We investigated the possibility that this network could be mapped using microarray technologies and modern bioinformatics methods on a dataset from whole blood in 99 untreated MS patients (36 Relapse Remitting MS, 43 Primary Progressive MS, and 20 Secondary Progressive MS) and 45 age-matched healthy controls, Methodology/Principal Findings We have used two different analytical methodologies: a differential expression analysis and a differential co-expression analysis, which have converged on a significant number of regulatory motifs that seem to be statistically overrepresented in genes which are either differentially expressed (or differentially co-expressed) in cases and controls (e.g. V$KROX_Q6, p-value < 3.31E-6; V$CREBP1_Q2, p-value < 9.93E-6, V$YY1_02, p-value < 1.65E-5). Conclusions/significance: Our analysis uncovered a network of transcription factors that potentially dysregulate several genes in MS or one or more of its disease subtypes. Analysing the published literature we have found that these transcription factors are involved in the early T-lymphocyte specification and commitment as well as in oligodendrocytes dedifferentiation and development. The most significant transcription factors motifs were for the Early Growth response EGR/KROX family, ATF2, YY1 (Yin and Yang 1), E2F-1/DP-1 and E2F-4/DP-2 heterodimers, SOX5, and CREB and ATF families.
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One of the challenges confronting contemporary education internationally is to ensure that students are provided with opportunities to make informed choices about future careers and to acquire the capacity to transition into these careers. Schools need to manage their curricula, teacher capacity, timetables, and diversity of student populations by offering pathways that are seen as engaging and meaningful to life beyond schooling. Traditionally, education in the senior years has privileged those students who intend to progress to advanced studies at university or in other professional careers. In more recent times, in response the need for more sophisticated technical knowledge in the trades and a growing skills shortages in these fields, schools have paid more attention to vocational education. It has been argued that the vocational aspect of the school curriculum is less well understood and poorly implemented in comparison with the traditional academic curricula. One attempt to address this issue is through the establishment of school-industry partnerships. This paper explores the process of knowledge transfer between industry and schools in these partnerships. The paper theorises how knowledge that is valued and foundational in workplace employment can inform school curricula and pedagogical practices. The paper draws on theories of organisational knowledge, workplace learning and experiential learning to explore strategies that enhance school-to-employment transition outcomes.
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Background: To report the incidence and risk factors for hypotony and estimate the risk of sympathetic ophthalmia following diode laser trans-scleral cyclophotocoagulation (TSCPC). Design: Retrospective study using data from a private tertiary glaucoma clinic and review of the literature. Participants: Seventy eyes of 70 patients with refractory glaucoma who received TSCPC treatment. Methods: Review of the records of consecutive patients who underwent TSCPC by a single ophthalmic surgeon and review of the literature. Main Outcome Measures: Hypotony (including phthisis bulbi), sympathetic ophthalmia. Results: Seven eyes (10%; CI 5-19%) developed hypotony and included 4 eyes that developed phthisis. Higher total energy delivered during TSCPC treatment was associated with an increased risk of hypotony: eyes that developed hypotony received a mean total energy of 192.5 ± 73.2 joules, compared to a mean of 152.9 ± 83.2 joules in hypotony-free cases. The difference in mean energy delivered between the hypotony and non-hypotony group was 38.53 (95% CI: -27.57 to 104.63). The risk of sympathetic ophthalmia estimated from a review of the published literature and current series was one in 1512, or 0.07% (CI 0.03% - 0.17%). Conclusions: Total laser energy is one of several risk factors that act in a sufficient component cause-model to produce hypotony in an individual patient. The small sample size precluded inference for other individual putative risk factors but titrating laser energy may help decrease the occurrence of hypotony. The risk of sympathetic ophthalmia calculated from the literature is likely an overestimate caused by publication bias.
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Purpose To examine choroidal thickness (ChT) and its spatial distribution across the posterior pole in pediatric subjects with normal ocular health and minimal refractive error. Methods ChT was assessed using spectral domain optical coherence tomography (OCT) in 194 children aged between 4-12 years, with spherical equivalent refractive errors between +1.25 and -0.50 DS. A series of OCT scans were collected, imaging the choroid along 4 radial scan lines centered on the fovea (each separated by 45°). Frame averaging was used to reduce noise and enhance chorio-scleral junction visibility. The transverse scale of each scan was corrected to account for magnification effects associated with axial length. Two independent masked observers manually segmented the OCT images to determine ChT at foveal centre, and averaged across a series of perifoveal zones over the central 5 mm. Results The average subfoveal ChT was 330 ± 65 µm (range 189-538 µm), and was significantly influenced by age (p=0.04). The ChT of the 4 to 6 year old age group (312 ± 62 µm) was significantly thinner compared to the 7 to 9 year olds (337 ± 65 µm, p<0.05) and bordered on significance compared to the 10 to 12 year olds (341 ± 61 µm, p=0.08). ChT also exhibited significant variation across the posterior pole, being thicker in more central regions. The choroid was thinner nasally and inferiorly compared to temporally and superiorly. Multiple regression analysis revealed age, axial length and anterior chamber depth were significantly associated with subfoveal ChT (p<0.001). Conclusions ChT increases significantly from early childhood to adolescence. This appears to be a normal feature of childhood eye growth.
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Purpose Commencing selected workouts with low muscle glycogen availability augments several markers of training adaptation compared with undertaking the same sessions with normal glycogen content. However, low glycogen availability reduces the capacity to perform high-intensity (>85% of peak aerobic power (V·O2peak)) endurance exercise. We determined whether a low dose of caffeine could partially rescue the reduction in maximal self-selected power output observed when individuals commenced high-intensity interval training with low (LOW) compared with normal (NORM) glycogen availability. Methods Twelve endurance-trained cyclists/triathletes performed four experimental trials using a double-blind Latin square design. Muscle glycogen content was manipulated via exercise–diet interventions so that two experimental trials were commenced with LOW and two with NORM muscle glycogen availability. Sixty minutes before an experimental trial, subjects ingested a capsule containing anhydrous caffeine (CAFF, 3 mg-1·kg-1 body mass) or placebo (PLBO). Instantaneous power output was measured throughout high-intensity interval training (8 × 5-min bouts at maximum self-selected intensity with 1-min recovery). Results There were significant main effects for both preexercise glycogen content and caffeine ingestion on power output. LOW reduced power output by approximately 8% compared with NORM (P < 0.01), whereas caffeine increased power output by 2.8% and 3.5% for NORM and LOW, respectively, (P < 0.01). Conclusion We conclude that caffeine enhanced power output independently of muscle glycogen concentration but could not fully restore power output to levels commensurate with that when subjects commenced exercise with normal glycogen availability. However, the reported increase in power output does provide a likely performance benefit and may provide a means to further enhance the already augmented training response observed when selected sessions are commenced with reduced muscle glycogen availability. It has long been known that endurance training induces a multitude of metabolic and morphological adaptations that improve the resistance of the trained musculature to fatigue and enhance endurance capacity and/or exercise performance (13). Accumulating evidence now suggests that many of these adaptations can be modified by nutrient availability (9–11,21). Growing evidence suggests that training with reduced muscle glycogen using a “train twice every second day” compared with a more traditional “train once daily” approach can enhance the acute training response (29) and markers representative of endurance training adaptation after short-term (3–10 wk) training interventions (8,16,30). Of note is that the superior training adaptation in these previous studies was attained despite a reduction in maximal self-selected power output (16,30). The most obvious factor underlying the reduced intensity during a second training bout is the reduction in muscle glycogen availability. However, there is also the possibility that other metabolic and/or neural factors may be responsible for the power drop-off observed when two exercise bouts are performed in close proximity. Regardless of the precise mechanism(s), there remains the intriguing possibility that the magnitude of training adaptation previously reported in the face of a reduced training intensity (Hulston et al. (16) and Yeo et al.) might be further augmented, and/or other aspects of the training stimulus better preserved, if power output was not compromised. Caffeine ingestion is a possible strategy that might “rescue” the aforementioned reduction in power output that occurs when individuals commence high-intensity interval training (HIT) with low compared with normal glycogen availability. Recent evidence suggests that, at least in endurance-based events, the maximal benefits of caffeine are seen at small to moderate (2–3 mg·kg-1 body mass (BM)) doses (for reviews, see Refs. (3,24)). Accordingly, in this study, we aimed to determine the effect of a low dose of caffeine (3 mg·kg-1 BM) on maximal self-selected power output during HIT commenced with either normal (NORM) or low (LOW) muscle glycogen availability. We hypothesized that even under conditions of low glycogen availability, caffeine would increase maximal self-selected power output and thereby partially rescue the reduction in training intensity observed when individuals commence HIT with low glycogen availability.
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This study was conducted within the context of a flexible education institution where conventional educational assessment practices and tests fail to recognise and assess the creativity and cultural capital of a cohort of marginalised young people. A new assessment model which included an electronic-portfolio-social-networking system (EPS) was developed and trialled to identify and exhibit evidence of students' learning. The study aimed to discern unique forms of cultural capital (Bourdieu, 1986) possessed by students who attend the Edmund Rice Education Australia Flexible Learning Centre Network (EREAFLCN). The EPS was trialled at the case study schools in an intervention and developed a space where students could make evident culturally specific forms of capital and funds of knowledge (Gonzalez, Moll, & Amanti, 2005). These resources were evaluated, modified and developed through dialogic processes utilising assessment for learning approaches (Qualifications and Curriculum Development Agency, 2009) in online and classroom settings. Students, peers and staff engaged in the recognition, judgement, revision and evaluation of students' cultural capital in a subfield of exchange (Bourdieu, 1990). The study developed the theory of assessment for learning as a field of exchange incorporating an online system as a teaching and assessment model. The term efield has been coined to describe this particular capital exchange model. A quasi-ethnographic approach was used to develop a collective case study (Stake, 1995). This case study involved an in-depth exploration of five students' forms of cultural capital and the ways in which this capital could be assessed and exchanged using the efield model. A comparative analysis of the five cases was conducted to identify the emergent issues of students' recognisable cultural capital resources and the processes of exchange that can be facilitated to acquire legitimate credentials for these students in the Australian field of education. The participants in the study were young people at two EREAFLC schools aged between 12 and 18 years. Data was collected through interviews, observations and examination of documents made available by the EREAFLCN. The data was coded and analysed using a theoretical framework based on Bourdieu's analytical tools and a sociocultural psychology theoretical perspective. Findings suggest that processes based on dialogic relationships can identify and recognise students' forms of cultural capital that are frequently misrecognised in mainstream school environments. The theory of assessment for learning as a field of exchange was developed into praxis and integrated in an intervention. The efield model was found to be an effective sociocultural tool in converting and exchanging students' capital resources for legitimated cultural and symbolic capital in the field of education.
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Capstone units are generally seen to have three main aims: integrating the program, reflecting on prior learning, and transitioning into the workplace. However, research indicates that most programs do not achieve outcomes in all three areas with Henscheid (2000) revealing that integration is the major goal of many capstone programs. As well, in the accounting education literature there has been little empirical evidence relating to the effectiveness of student learning as a result of implementing a capstone unit. This study reports on the development and implementation of an accountancy capstone unit at the Queensland University of Technology (QUT), which began in 2006. The main features of this capstone unit are: the use of problem-based learning (PBL); integration of the program; the development of a professional identity whereby classes are broken up into groups of a maximum of five students who take on the persona of a professional accounting firm for an entire semester; and the students, acting as professional advisors within that firm, are required to solve a series of unstructured, multi-dimensional accounting problems based on limited given facts. This process is similar to a professional advisor asking a client about the facts relating to the particular problem of the client and then solving the problem. The research was conducted over nine semesters and involved the collection of both quantitative and qualitative data from a student questionnaire. The results indicate that in terms of student perceptions, the capstone unit was very effective in enhancing integration of the program and enhancing professional identity thereby assisting student transition into the professional accounting workplace. Our approach therefore meets two of the three generally accepted aims of a capstone unit. With accounting educators striving to maximise student learning from a finite set of resources, this approach using PBL has resulted in improved learning outcomes for accounting students about to enter the workplace as professionals.
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Purpose To determine the rate of recurrence and associated risk factors following the use of mitomycin C (MMC) and/or interferon alpha-2b (IFN) for management of non-invasive ocular surface squamous neoplasia (OSSN). Design Retrospective non-comparative interventional case series. Methods Clinical practice setting of 135 patients treated consecutively with topical MMC (0.4 mg/mL) and/or IFN (1 million units/mL) for OSSN observed for clinical recurrence. Results Clinical recurrences were diagnosed in 19 of 135 (14.1%) eyes following topical treatment. The mean time to recurrence was 17.2 months (range 4 - 61) with 14 (73.7%) recurring within a two year period. There was no greater risk of recurrence identified for variables including lesion size, lesion location, gender, age, treatment type or duration. Post-hoc log-Rank pairwise comparisons revealed that lesions initially treated using surgery alone had significantly reduced time to recurrence (21.1 ± 5.6 months) compared to previous topical treatment with MMC (with or without surgery) (29.6 ± 4.7 months) (p = 0.04) and primary OSSN (23.2 ± 1.8 months) (p = 0.09). Conclusions Topical MMC and IFN are an effective treatment modality for a wide range of non-invasive OSSN. Topical therapy avoids the morbidity of excisional surgery with equivalent or reduced recurrence rates and should be considered as primary therapy.
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Purpose: To examine between eye differences in corneal higher order aberrations and topographical characteristics in a range of refractive error groups. Methods: One hundred and seventy subjects were recruited including; 50 emmetropic isometropes, 48 myopic isometropes (spherical equivalent anisometropia ≤ 0.75 D), 50 myopic anisometropes (spherical equivalent anisometropia ≥ 1.00 D) and 22 keratoconics. The corneal topography of each eye was captured using the E300 videokeratoscope (Medmont, Victoria, Australia) and analyzed using custom written software. All left eye data were rotated about the vertical midline to account for enantiomorphism. Corneal height data were used to calculate the corneal wavefront error using a ray tracing procedure and fit with Zernike polynomials (up to and including the eighth radial order). The wavefront was centred on the line of sight by using the pupil offset value from the pupil detection function in the videokeratoscope. Refractive power maps were analysed to assess corneal sphero-cylindrical power vectors. Differences between the more myopic (or more advanced eye for keratoconics) and the less myopic (advanced) eye were examined. Results: Over a 6 mm diameter, the cornea of the more myopic eye was significantly steeper (refractive power vector M) compared to the fellow eye in both anisometropes (0.10 ± 0.27 D steeper, p = 0.01) and keratoconics (2.54 ± 2.32 D steeper, p < 0.001) while no significant interocular difference was observed for isometropic emmetropes (-0.03 ± 0.32 D) or isometropic myopes (0.02 ± 0.30 D) (both p > 0.05). In keratoconic eyes, the between eye difference in corneal refractive power was greatest inferiorly (associated with cone location). Similarly, in myopic anisometropes, the more myopic eye displayed a central region of significant inferior corneal steepening (0.15 ± 0.42 D steeper) relative to the fellow eye (p = 0.01). Significant interocular differences in higher order aberrations were only observed in the keratoconic group for; vertical trefoil C(3,-3), horizontal coma C(3,1) secondary astigmatism along 45 C(4, -2) (p < 0.05) and vertical coma C(3,-1) (p < 0.001). The interocular difference in vertical pupil decentration (relative to the corneal vertex normal) increased with between eye asymmetry in refraction (isometropia 0.00 ± 0.09, anisometropia 0.03 ± 0.15 and keratoconus 0.08 ± 0.16 mm) as did the interocular difference in corneal vertical coma C (3,-1) (isometropia -0.006 ± 0.142, anisometropia -0.037 ± 0.195 and keratoconus -1.243 ± 0.936 μm) but only reached statistical significance for pair-wise comparisons between the isometropic and keratoconic groups. Conclusions: There is a high degree of corneal symmetry between the fellow eyes of myopic and emmetropic isometropes. Interocular differences in corneal topography and higher order aberrations are more apparent in myopic anisometropes and keratoconics due to regional (primarily inferior) differences in topography and between eye differences in vertical pupil decentration relative to the corneal vertex normal. Interocular asymmetries in corneal optics appear to be associated with anisometropic refractive development.