905 resultados para Causal attribution
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Purpose. Contrast adaptation may induce an error signal for emmetropization. This research aims to determine whether reading causes contrast adaptation in children and, if so, to determine whether myopes exhibit greater contrast adaptation than emmetropes. Methods. Baseline contrast sensitivity was determined in 34 emmetropic and 34 spectacle-corrected myopic children for 0.5, 1.2, 2.7, 4.4, and 6.2 cycles per degree (cpd) horizontal sine-wave gratings. Effects of near tasks on contrast sensitivity were determined during periods spent looking at a 6.2 cpd horizontal grating and during periods spent reading lines of English text, with 1.2 cpd row frequency and 6 cpd stroke frequency. Results. Both emmetropic and myopic groups (mean ± SD; age, 10.3 ± 1.4 years) showed reduced contrast sensitivity during both near tasks, with greatest overall adaptation at 6.2 cpd. Adaptation induced by viewing the grating (0.15 ± 0.17 log unit [40%]; range, 0.07-0.27 log unit) was significantly greater than adaptation induced by reading text (0.11 ± 0.18 log unit [29%], 0.08-0.16 log unit) (F(1,594) = 10.7; P = 0.001). Myopic children showed significantly greater adaptation across the tasks (0.15 ± 0.18 log unit [42%]) than emmetropic children (0.10 ± 0.16 log unit [26%]) (F(1,66) = 7.30; P = 0.009), with the greatest difference occurring at 4.4 cpd (mean, 0.11 log unit [30%]). Conclusions. Grating and reading tasks induced contrast adaptation; viewing horizontal gratings induced greater adaptation than reading, and myopes exhibited greater adaptation than emmetropes. Contrast adaptation effects may underlie findings of prolonged near work being associated with myopia. However, our research does not show whether this is consequential or causal.
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The aim of this investigation was to elucidate the reductions in muscle, skin and core temperature following exposure to −110°C whole body cryotherapy (WBC), and compare these to 8°C cold water immersion (CWI). Twenty active male subjects were randomly assigned to a 4-min exposure of WBC or CWI. A minimum of 7 days later subjects were exposed to the other treatment. Muscle temperature in the right vastus lateralis (n = 10); thigh skin (average, maximum and minimum) and rectal temperature (n = 10) were recorded before and 60 min after treatment. The greatest reduction (P<0.05) in muscle (mean ± SD; 1 cm: WBC, 1.6±1.2°C; CWI, 2.0±1.0°C; 2 cm: WBC, 1.2±0.7°C; CWI, 1.7±0.9°C; 3 cm: WBC, 1.6±0.6°C; CWI, 1.7±0.5°C) and rectal temperature (WBC, 0.3±0.2°C; CWI, 0.4±0.2°C) were observed 60 min after treatment. The largest reductions in average (WBC, 12.1±1.0°C; CWI, 8.4±0.7°C), minimum (WBC, 13.2±1.4°C; CWI, 8.7±0.7°C) and maximum (WBC, 8.8±2.0°C; CWI, 7.2±1.9°C) skin temperature occurred immediately after both CWI and WBC (P<0.05). Skin temperature was significantly lower (P<0.05) immediately after WBC compared to CWI. The present study demonstrates that a single WBC exposure decreases muscle and core temperature to a similar level of those experienced after CWI. Although both treatments significantly reduced skin temperature, WBC elicited a greater decrease compared to CWI. These data may provide information to clinicians and researchers attempting to optimise WBC and CWI protocols in a clinical or sporting setting.
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This study seeks to examine the causality of non-nursing and nursing stressors on the job satisfaction of nurses and how coping strategies have a mediating influence on this relationship in the context of sector-wide reform. To conceptualize the relationships, a mediation path model was developed. Data were collected at two time points using a self-completed online survey over a six monthly interval. During time 1, 306 Australian nurses completed the online survey. In the first wave (time 1), 306 Australian nurses completed the survey. In the second wave (time 2), matched survey data were collected from 119 nurses. The analysis showed a significant causal relationship between time 1 administrative and role stressors and an increase in nursing stress in time 2. A significant relationship was also identified between job specific context stressors and the adoption of effective coping strategies to deal with increased level of change-induced stress and strain and the likelihood of reporting higher level of job satisfaction in time 2. This study contributes by providing an integrated theoretical perspective on how stress affects retention that has so far been elusive. This is useful to researchers wanting to examine this phenomenon further and practitioners responsible for implementing change programs.
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An ongoing challenge in behavioral economics is to understand the variations observed in risk attitudes as a function of their environmental context. Of particular interest is the effect of wealth on risk attitudes. The research in this area has however faced two constraints: the difficulty to study the causal effects of large changes in wealth, and the causal effects of losses on risk behavior. The present paper address this double limitation by providing evidence of the variation of risk attitude after large losses using a natural disaster (Brisbane floods) as the setting for a natural experiment.
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It is often argued that consumption of alcohol, tobacco and drugs is detrimental to the cognitive abilities of teenagers. In order to disentangle a possible causal effect of these substances use from a self-selection bias, we control for pupils previous performance and for their previous rate of progression applying a DiDiD strategy. Using the NELS 1988 panel dataset, we find that the effects of alcohol and tobacco on test scores disappear once the selection bias is controlled for (this does not preclude long term detrimental effects). However, we find reliable evidence that heavy use of drugs (marijuana and cocaine) has direct detrimental effects on educational achievements. Hence, our results may have significant policy implications.
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Background: Currently in the Australian higher education sector higher productivity from allied health clinical education placements are a contested issue. This paper will report results of a study that investigated output changes associated with occupational therapy and nutrition/dietetics clinical education placements in Queensland, Australia. Supervisors’ and students’ time use during placements and how this changes for supervisors compared to when students are not present in the workplace is also presented. Methodology/Principal Findings: A cohort design was used with students from four Queensland universities, and their supervisors employed by Queensland Health. There was an increasing trend in the number of occasions of service delivered when the students were present, and a statistically significant increase in the daily mean length of occasions of service delivered during the placement compared to pre-placement levels. For project-based placements that were not directly involved in patient care, supervisors’ project activity time decreased during placements, with students undertaking considerably more time in project activities. Conclusions/Significance: A novel method for estimating productivity and time use changes during clinical education programs for allied health disciplines has been applied. During clinical education placements there was a net increase in outputs, suggesting supervisors engage in longer consultations with patients for the purpose of training students, while maintaining patient numbers. Other activities are reduced. This paper is the first time these data have been shown and form a good basis for future assessments of the economic impact of student placements for allied health disciplines.
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There remains a substantial shortfall in treatment of severe skeletal injuries. The current gold standard of autologous bone grafting from the same patient, has many undesirable side effects associated such as donor site morbidity. Tissue engineering seeks to offer a solution to this problem. The primary requirements for tissue engineered scaffolds have already been well established, and many materials, such as polyesters, present themselves as potential candidates for bone defects; they have comparable structural features, but they often lack the required osteoconductivity to promote adequate bone regeneration. By combining these materials with biological growth factors; which promote the infiltration of cells into the scaffold as well as the differentiation into the specific cell and tissue type, it is possible to increase the formation of new bone. However cost and potential complications associated with growth factors means controlled release is an important consideration in the design of new bone tissue engineering strategies. This review will cover recent research in the area of encapsulation and release of growth factors within a variety of different polymeric scaffolds.
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The work by graduate teachers in this volume represent intentional design of learning experiences using technology for Early Childhood settings. They were given a two-part design task: a sequence of lessons organised around a themed project; and the collection of resources to support such activities. The project had to be constructive in nature where the children built objects and representations that were meaningful to them. The excellent works presented here offer a range of approaches that would be suitable in a variety of contexts. Because they are reasoned, these projects offer flexibility in implementation along with confidence that they would be effective.
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The proteins LMO4 and DEAF1 contribute to the proliferation of mammary epithelial cells. During breast cancer LMO4 is upregulated, affecting its interaction with other protein partners. This may set cells on a path to tumour formation. LMO4 and DEAF1 interact, but it is unknown how they cooperate to regulate cell proliferation. In this study, we identify a specific LMO4-binding domain in DEAF1. This domain contains an unstructured region that directly contacts LMO4, and a coiled coil that contains the DEAF1 nuclear export signal (NES). The coiled coil region can form tetramers and has the typical properties of a coiled coil domain. Using a simple cell-based assay, we show that LMO4 modulates the activity of the DEAF NES, causing nuclear accumulation of a construct containing the LMO4-interaction region of DEAF1.
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Introduction: Inherent and acquired cisplatin resistance reduces the effectiveness of this agent in the management of non-small cell lung cancer (NSCLC). Understanding the molecular mechanisms underlying this process may result in the development of novel agents to enhance the sensitivity of cisplatin. Methods: An isogenic model of cisplatin resistance was generated in a panel of NSCLC cell lines (A549, SKMES-1, MOR, H460). Over a period of twelve months, cisplatin resistant (CisR) cell lines were derived from original, age-matched parent cells (PT) and subsequently characterized. Proliferation (MTT) and clonogenic survival assays (crystal violet) were carried out between PT and CisR cells. Cellular response to cisplatin-induced apoptosis and cell cycle distribution were examined by FACS analysis. A panel of cancer stem cell and pluripotent markers was examined in addition to the EMT proteins, c-Met and β-catenin. Cisplatin-DNA adduct formation, DNA damage (γH2AX) and cellular platinum uptake (ICP-MS) was also assessed. Results: Characterisation studies demonstrated a decreased proliferative capacity of lung tumour cells in response to cisplatin, increased resistance to cisplatin-induced cell death, accumulation of resistant cells in the G0/G1 phase of the cell cycle and enhanced clonogenic survival ability. Moreover, resistant cells displayed a putative stem-like signature with increased expression of CD133+/CD44+cells and increased ALDH activity relative to their corresponding parental cells. The stem cell markers, Nanog, Oct-4 and SOX-2, were significantly upregulated as were the EMT markers, c-Met and β-catenin. While resistant sublines demonstrated decreased uptake of cisplatin in response to treatment, reduced cisplatin-GpG DNA adduct formation and significantly decreased γH2AX foci were observed compared to parental cell lines. Conclusion: Our results identified cisplatin resistant subpopulations of NSCLC cells with a putative stem-like signature, providing a further understanding of the cellular events associated with the cisplatin resistance phenotype in lung cancer. © 2013 Barr et al.
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Many organisations, companies and libraries started to use participatory webs to extend their services and engage more users. However, some librarians are still hesitated to implement participatory webs in their libraries, particularly in developing countries. This paper explores the advantages and disadvantages of participatory webs focusing on collaborative tagging. This paper draws from the literature of published articles discussing topics but not limited to participatory webs, participatory libraries, collaborative tagging, folksonomy and taxonomy. The advantages of implementation of the participatory webs in the library outweigh the disadvantages of it. Participatory webs do not necessarily mean the death of information organisation but it can supplement and improves information organisation in the library. This paper may help to broaden knowledge of LIS professionals in the implementation of participatory webs in the library.
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This piece is a contribution to a symposium on the relationship of literacy studies to composition studies. Three central foci of literacy studies have direct implications for composition studies: the shift from canonical to everyday texts, practices and literacy events; acknowledgement of ubiquitious student and community cultural and linguistic diversity; and the impact of new technologies on writing and education. The case is made for a major reconnoitering of the historical foundations of composition studies in theories of rhetoric and grammar.
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Internet technologies have fundamentally changed the way we obtain access to legal documents and information about the law. However, for judgments of courts and tribunals, copyright management and licensing practices have not kept pace with the digital and online technologies which are now ubiquitous in the web 2.0 era. Under the provisions of the Copyright Act 1968 and the licensing statements on the Australian courts’ websites, judgments may generally be read online, downloaded, reproduced and printed out for personal, non-commercial use or ”in house” use by an organisation. However, beyond these permitted acts, the extent to which judgments can be copied and distributed in digital form online remains unclear. Open content licences (in particular, the Creative Commons (CC) licences) offer an effective mechanism for managing copyright in judgments in a manner that supports their wide public dissemination and reuse while also protecting their integrity and accuracy.