302 resultados para Random Access


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Background: Despite important implications for the budgets, statistical power and generalisability of research findings, detailed reports of recruitment and retention in randomised controlled trials (RCTs) are rare. The NOURISH RCT evaluated a community-based intervention for first-time mothers that promoted protective infant feeding practices as a primary prevention strategy for childhood obesity. The aim of this paper is to provide a detailed description and evaluation of the recruitment and retention strategies used. Methods: A two stage recruitment process designed to provide a consecutive sampling framework was used. First time mothers delivering healthy term infants were initially approached in postnatal wards of the major maternity services in two Australian cities for consent to later contact (Stage 1). When infants were about four months old mothers were re-contacted by mail for enrolment (Stage 2), baseline measurements (Time 1) and subsequent random allocation to the intervention or control condition. Outcomes were assessed at infant ages 14 months (Time 2) and 24 months (Time 3). Results: At Stage 1, 86% of eligible mothers were approached and of these women, 76% consented to later contact. At Stage 2, 3% had become ineligible and 76% could be recontacted. Of the latter, 44% consented to full enrolment and were allocated. This represented 21% of mothers screened as eligible at Stage 1. Retention at Time 3 was 78%. Mothers who did not consent or discontinued the study were younger and less likely to have a university education. Conclusions: The consent and retention rates of our sample of first time mothers are comparable with or better than other similar studies. The recruitment strategy used allowed for detailed information from non-consenters to be collected; thus selection bias could be estimated. Recommendations for future studies include being able to contact participants via mobile phone (particular text messaging), offering home visits to reduce participant burden and considering the use of financial incentives to support participant retention.

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In this paper we investigate the distribution of the product of Rayleigh distributed random variables. Considering the Mellin-Barnes inversion formula and using the saddle point approach we obtain an upper bound for the product distribution. The accuracy of this tail-approximation increases as the number of random variables in the product increase.

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This article provides a consideration of the problem of equity in education. In the first part of the discussion, the author draws on philosophical and sociological literatures to consider what equity means and its implications for education. Drawing on work by Burbules, Lord & Sherman, she looks to curriculum as a condition of access and the importance of learning support structures in bringing about equitable educational outcomes, conceived in terms of Amy Gutmanns’s democratic threshold. The paper offers a conceptual-theoretical model for thinking about the resourcing and curricular requirements for equity in contemporary liberal democratic societies, contrasting the social and economic policy mixes employed by governments situated at different points along a liberty/equality continuum.

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The convergence of corporate social responsibility (CSR) and corporate governance has immense impact on the participants in global supply chains. The global buyers and retailers tend to incorporate CSR in all stages of product manufacturing within their supply chains. The incorporated CSR thus creates the difficulty to small- and medium-sized manufacturing enterprises (SMEs). Incompetence in standardized CSR practices is an important issue that causes SMEs either losing their scope to access global market directly or serving as subcontractors to large enterprises. This article explores this issue by focusing on Bangladeshi SMEs under the CSR requirement of the important global buyer.

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Background: A random QTL effects model uses a function of probabilities that two alleles in the same or in different animals at a particular genomic position are identical by descent (IBD). Estimates of such IBD probabilities and therefore, modeling and estimating QTL variances, depend on marker polymorphism, strength of linkage and linkage disequilibrium of markers and QTL, and the relatedness of animals in the pedigree. The effect of relatedness of animals in a pedigree on IBD probabilities and their characteristics was examined in a simulation study. Results: The study based on nine multi-generational family structures, similar to a pedigree structure of a real dairy population, distinguished by an increased level of inbreeding from zero to 28 % across the studied population. Highest inbreeding level in the pedigree, connected with highest relatedness, was accompanied by highest IBD probabilities of two alleles at the same locus, and by lower relative variation coefficients. Profiles of correlation coefficients of IBD probabilities along the marked chromosomal segment with those at the true QTL position were steepest when the inbreeding coefficient in the pedigree was highest. Precision of estimated QTL location increased with increasing inbreeding and pedigree relatedness. A method to assess the optimum level of inbreeding for QTL detection is proposed, depending on population parameters. Conclusions: An increased overall relationship in a QTL mapping design has positive effects on precision of QTL position estimates. But the relationship of inbreeding level and the capacity for QTL detection depending on the recombination rate of QTL and adjacent informative marker is not linear. © 2010 Freyer et al., licensee BioMed Central Ltd.

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Although digital technology has, in theory, made it possible for many more people to access content at no extra cost, fewer people than ever before are able to read the books written by university-based researchers. This article looks, very briefly, at the role that open access licenses might play in reviving the scholarly monograph: a specialised area of academic publishing that has seen sales decline by more than 90% over the past three decades. It also introduces a new approach to funding open-access scholarly books being pioneered by the not-for-profit social enterprise Knowledge Unlatched.

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Private data stored on smartphones is a precious target for malware attacks. A constantly changing environment, e.g. switching network connections, can cause unpredictable threats, and require an adaptive approach to access control. Context-based access control is using dynamic environmental information, including it into access decisions. We propose an "ecosystem-in-an-ecosystem" which acts as a secure container for trusted software aiming at enterprise scenarios where users are allowed to use private devices. We have implemented a proof-of-concept prototype for an access control framework that processes changes to low-level sensors and semantically enriches them, adapting access control policies to the current context. This allows the user or the administrator to maintain fine-grained control over resource usage by compliant applications. Hence, resources local to the trusted container remain under control of the enterprise policy. Our results show that context-based access control can be done on smartphones without major performance impact.

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Theoretical foundations of higher order spectral analysis are revisited to examine the use of time-varying bicoherence on non-stationary signals using a classical short-time Fourier approach. A methodology is developed to apply this to evoked EEG responses where a stimulus-locked time reference is available. Short-time windowed ensembles of the response at the same offset from the reference are considered as ergodic cyclostationary processes within a non-stationary random process. Bicoherence can be estimated reliably with known levels at which it is significantly different from zero and can be tracked as a function of offset from the stimulus. When this methodology is applied to multi-channel EEG, it is possible to obtain information about phase synchronization at different regions of the brain as the neural response develops. The methodology is applied to analyze evoked EEG response to flash visual stimulii to the left and right eye separately. The EEG electrode array is segmented based on bicoherence evolution with time using the mean absolute difference as a measure of dissimilarity. Segment maps confirm the importance of the occipital region in visual processing and demonstrate a link between the frontal and occipital regions during the response. Maps are constructed using bicoherence at bifrequencies that include the alpha band frequency of 8Hz as well as 4 and 20Hz. Differences are observed between responses from the left eye and the right eye, and also between subjects. The methodology shows potential as a neurological functional imaging technique that can be further developed for diagnosis and monitoring using scalp EEG which is less invasive and less expensive than magnetic resonance imaging.

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The ultimate goal of an access control system is to allocate each user the precise level of access they need to complete their job - no more and no less. This proves to be challenging in an organisational setting. On one hand employees need enough access to the organisation’s resources in order to perform their jobs and on the other hand more access will bring about an increasing risk of misuse - either intentionally, where an employee uses the access for personal benefit, or unintentionally, through carelessness or being socially engineered to give access to an adversary. This thesis investigates issues of existing approaches to access control in allocating optimal level of access to users and proposes solutions in the form of new access control models. These issues are most evident when uncertainty surrounding users’ access needs, incentive to misuse and accountability are considered, hence the title of the thesis. We first analyse access control in environments where the administrator is unable to identify the users who may need access to resources. To resolve this uncertainty an administrative model with delegation support is proposed. Further, a detailed technical enforcement mechanism is introduced to ensure delegated resources cannot be misused. Then we explicitly consider that users are self-interested and capable of misusing resources if they choose to. We propose a novel game theoretic access control model to reason about and influence the factors that may affect users’ incentive to misuse. Next we study access control in environments where neither users’ access needs can be predicted nor they can be held accountable for misuse. It is shown that by allocating budget to users, a virtual currency through which they can pay for the resources they deem necessary, the need for a precise pre-allocation of permissions can be relaxed. The budget also imposes an upper-bound on users’ ability to misuse. A generalised budget allocation function is proposed and it is shown that given the context information the optimal level of budget for users can always be numerically determined. Finally, Role Based Access Control (RBAC) model is analysed under the explicit assumption of administrators’ uncertainty about self-interested users’ access needs and their incentives to misuse. A novel Budget-oriented Role Based Access Control (B-RBAC) model is proposed. The new model introduces the notion of users’ behaviour into RBAC and provides means to influence users’ incentives. It is shown how RBAC policy can be used to individualise the cost of access to resources and also to determine users’ budget. The implementation overheads of B-RBAC is examined and several low-cost sub-models are proposed.

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utomatic pain monitoring has the potential to greatly improve patient diagnosis and outcomes by providing a continuous objective measure. One of the most promising methods is to do this via automatically detecting facial expressions. However, current approaches have failed due to their inability to: 1) integrate the rigid and non-rigid head motion into a single feature representation, and 2) incorporate the salient temporal patterns into the classification stage. In this paper, we tackle the first problem by developing a “histogram of facial action units” representation using Active Appearance Model (AAM) face features, and then utilize a Hidden Conditional Random Field (HCRF) to overcome the second issue. We show that both of these methods improve the performance on the task of pain detection in sequence level compared to current state-of-the-art-methods on the UNBC-McMaster Shoulder Pain Archive.

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The impact of research can be measured by use or citation count. The more widely available that research outputs are; the more likely they are to be used, and the higher the impact. Making the author-manuscript version of research outputs freely available via the institutional repository greatly increases the availability of research outputs and can increase the impact. QUT ePrints, the open access institutional repository of research outputs at Queensland University of Technology (QUT), Australia, was established in 2003 and is managed by the QUT Library. The repository now contains over 39,000 records. More than 21,000 of these records have full-text copies attached as result of continuous effort to maintain momentum and encourage academic engagement. The full-text deposit rate has continued to increase over time and, in 2012 (August, at the time of writing), 88% of the records for works published in 2012 provide access to a full-text copy. Achieving success has required a long term approach to collaboration, open access advocacy, repository promotion, support for the deposit process, and ongoing system development. This paper discusses the various approaches adopted by QUT Library, in collaboration with other areas of the University, to achieve success. Approaches include mainstreaming the repository via having it report to the University Research and Innovation Committee; regular provision of deposit rate data to faculties; championing key academic supporters; and holding promotional competitions and events such as during Open Access Week. Support and training is provided via regular deposit workshops with academics and faculty research support groups and via the provision of online self-help information. Recent system developments have included the integration of citation data (from Scopus and Web of Science) and the development of a statistical reporting system which incentivise engagement.

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Historically a significant gap between male and female wages has existed in the Australian labour market. Indeed this wage differential was institutionalised in the 1912 arbitration decision which determined that the basic female wage would be set at between 54 and 66 per cent of the male wage. More recently however, the 1969 and 1972 Equal Pay Cases determined that male/female wage relativities should be based upon the premise of equal pay for work of equal value. It is important to note that the mere observation that average wages differ between males and females is not sine qua non evidence of sex discrimination. Economists restrict the definition of wage discrimination to cases where two distinct groups receive different average remuneration for reasons unrelated to differences in productivity characteristics. This paper extends previous studies of wage discrimination in Australia (Chapman and Mulvey, 1986; Haig, 1982) by correcting the estimated male/female wage differential for the existence of non-random sampling. Previous Australian estimates of male/female human capital basedwage specifications together with estimates of the corresponding wage differential all suffer from a failure to address this issue. If the sample of females observed to be working does not represent a random sample then the estimates of the male/female wage differential will be both biased and inconsistent.

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There is currently little information available about reasons for contraceptive use or non-use among young Australian women and the reasons for choosing specific types of contraceptive methods. A comprehensive life course perspective of women's experiences in using and obtaining contraceptives is lacking, particularly relating to women's perceived or physical barriers to access. This paper presents an analysis of qualitative data gathered from free-text comments provided by women born between 1973 and 1978 as part of their participation in the Australian Longitudinal Study on Women's Health. The Australian Longitudinal Study on Women's Health is a large cohort study involving over 40,000 women from three age groups (aged 18-23, aged 40-45 and aged 70-75) who were selected from the database of Medicare the Australian universal health insurance system in 1995. The women have been surveyed every 3 years about their health by mailed self-report surveys, and more recently online. Written comments from 690 women across five surveys from 1996 (when they were aged 18-23 years) to 2009 (aged 31-36 years) were examined. Factors relating to contraceptive use and barriers to access were identified and explored using thematic analysis. Side-effects, method satisfaction, family timing, and hormonal balance were relevant to young women using contraception. Most women who commented about a specific contraceptive method wrote about the oral contraceptive pill. While many women were positive or neutral about their method, noting its convenience or non-contraceptive benefits, many others were concerned about adverse effects, affordability, method failure, and lack of choice. Negative experiences with health services, lack of information, and cost were identified as barriers to access. As the cohort aged over time, method choice, changing patterns of use, side-effects, and negative experiences with health services remained important themes. Side-effects, convenience, and family timing play important roles in young Australian women's experiences of contraception and barriers to access. Contrary to assumptions, barriers to contraceptive access continue to be experienced by young women as they move into adulthood. Further research is needed about how to decrease barriers to contraceptive use and minimise negative experiences in order to ensure optimal contraceptive access for Australian women.

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In this paper we present an examination of the literature on the psychosocial aspects of hepatitis C (HCV), and ask what are the implications for patients and clinicians regarding access to treatment? Hepatitis C (HCV) is a blood-borne communicable disease that was identified in 1988. In Australia, an estimated 217,000 people live with HCV. The virus causes serious liver inflammation, can lead to liver cirrhosis and a small percentage of sufferers will develop hepatocellular carcinoma. Reports about the psychosocial aspects of HCV appeared from around 1994 indicating a similar set of societal responses to people with HIV; stigmatisation and discrimination. A number of calls were made for the establishment of counselling and support services to address the specific mental health needs of people with HCV. We conducted a systematic review of the literature between 2002-2012 about the psychosocial aspects of HCV and its relationship to access to treatment and identified a number of key issues that suggest the anticipated progress in this area has not been made. The majority of people with HCV already experience marginalisation, and the diagnosis of HCV further compounds their marginalisation through stigma and discrimination and complicates clinical decision-making around treatment. We conclude that the need for mental health services that are capable of addressing the complexities of the psychosocial aspects of HCV remains. Concomitantly, primary care clinicians require greater clarity and consistency about the clinical guidelines for HCV to meet the increasing expectations on them to deliver comprehensive patient management within primary care. (248 words)