879 resultados para meta study


Relevância:

30.00% 30.00%

Publicador:

Resumo:

Background Autism spectrum conditions (ASC) are a group of neurodevelopmental conditions characterized by difficulties in social interaction and communication alongside repetitive and stereotyped behaviours. ASC are heritable, and common genetic variants contribute substantial phenotypic variability. More than 600 genes have been implicated in ASC to date. However, a comprehensive investigation of candidate gene association studies in ASC is lacking. Methods In this study, we systematically reviewed the literature for association studies for 552 genes associated with ASC. We identified 58 common genetic variants in 27 genes that have been investigated in three or more independent cohorts and conducted a meta-analysis for 55 of these variants. We investigated publication bias and sensitivity and performed stratified analyses for a subset of these variants. Results We identified 15 variants nominally significant for the mean effect size, 8 of which had P values below a threshold of significance of 0.01. Of these 15 variants, 11 were re-investigated for effect sizes and significance in the larger Psychiatric Genomics Consortium dataset, and none of them were significant. Effect direction for 8 of the 11 variants were concordant between both the datasets, although the correlation between the effect sizes from the two datasets was poor and non-significant. Conclusions This is the first study to comprehensively examine common variants in candidate genes for ASC through meta-analysis. While for majority of the variants, the total sample size was above 500 cases and 500 controls, the total sample size was not large enough to accurately identify common variants that contribute to the aetiology of ASC.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Bin planning (arrangements) is a key factor in the timber industry. Improper planning of the storage bins may lead to inefficient transportation of resources, which threaten the overall efficiency and thereby limit the profit margins of sawmills. To address this challenge, a simulation model has been developed. However, as numerous alternatives are available for arranging bins, simulating all possibilities will take an enormous amount of time and it is computationally infeasible. A discrete-event simulation model incorporating meta-heuristic algorithms has therefore been investigated in this study. Preliminary investigations indicate that the results achieved by GA based simulation model are promising and better than the other meta-heuristic algorithm. Further, a sensitivity analysis has been done on the GA based optimal arrangement which contributes to gaining insights and knowledge about the real system that ultimately leads to improved and enhanced efficiency in sawmill yards. It is expected that the results achieved in the work will support timber industries in making optimal decisions with respect to arrangement of storage bins in a sawmill yard.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The microwave reflection, transmission and complex permittivity of paratoluene-2-sulfonic acid doped conducting polypyrrole (PPy/pTSA) coated Nylon-Lycra textiles in the 1-18 GHz frequency were investigated. The real part of permittivity increased with polymerization time and dopant concentration, reaching a plateau at certain dopant concentration and polymerization time. The imaginary part of permittivity showed a frequency dependent change throughout the tested range. All the samples had higher values of absorption than reflection. The total electromagnetic shielding effectiveness exceeded 80% for the highly pTSA doped samples coated for 3 hours.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Background The appropriate response of health care professionals to intimate partner violence is still a matter of debate. This article reports a meta-analysis of qualitative studies that answers 2 questions: (1) How do women with histories of intimate partner violence perceive the responses of health care professionals? and (2) How do women with histories of intimate partner violence want their health care providers to respond to disclosures of abuse?

Methods Multiple databases were searched from their start to July 1, 2004. Searches were complemented with citation tracking and contact with researchers. Inclusion criteria included a qualitative design, women 15 years or older with experience of intimate partner violence, and English language. Two reviewers independently applied criteria and extracted data. Findings from the primary studies were combined using a qualitative meta-analysis.

Results Twenty-nine articles reporting 25 studies (847 participants) were included. The emerging constructs were largely consistent across studies and did not vary by study quality. We ordered constructs by the temporal structure of consultations with health care professionals: before the abuse is discussed, at disclosure, and the immediate and further responses of the health care professional. Key constructs included a wish from women for responses from health care professionals that were nonjudgmental, nondirective, and individually tailored, with an appreciation of the complexity of partner violence. Repeated inquiry about partner violence was seen as appropriate by women who were at later stages of an abusive relationship.

Conclusion Women’s perceptions of appropriate and inappropriate responses partly depended on the context of the consultation, their own readiness to address the issue, and the nature of the relationship between the woman and the health care professional.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Appropriate choice of a kernel is the most important ingredient of the kernel-based learning methods such as support vector machine (SVM). Automatic kernel selection is a key issue given the number of kernels available, and the current trial-and-error nature of selecting the best kernel for a given problem. This paper introduces a new method for automatic kernel selection, with empirical results based on classification. The empirical study has been conducted among five kernels with 112 different classification problems, using the popular kernel based statistical learning algorithm SVM. We evaluate the kernels’ performance in terms of accuracy measures. We then focus on answering the question: which kernel is best suited to which type of classification problem? Our meta-learning methodology involves measuring the problem characteristics using classical, distance and distribution-based statistical information. We then combine these measures with the empirical results to present a rule-based method to select the most appropriate kernel for a classification problem. The rules are generated by the decision tree algorithm C5.0 and are evaluated with 10 fold cross validation. All generated rules offer high accuracy ratings.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The overall performance of a distributed system often depends on the effectiveness of its interconnection network. Thus, the study of the communication networks for distributed systems is very important, which is the focus of this paper. In particular, we address the problem of interconnection networks performance modeling for heterogeneous meta-computing systems. We consider the meta-computing system as a typical multi-cluster system. Since the heterogeneity is becoming common in such systems, we take into account network as well as cluster size heterogeneity to propose the model. To this end, we present an analytical network model and validate the model through comprehensive simulation. The results of the simulation demonstrated that the proposed model exhibits a good degree of accuracy for various system organizations and under different working conditions.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Introduction: Fall risk screening tools are frequently used as a part of falls prevention programs in hospitals. Design-related bias in evaluations of tool predictive accuracy could lead to overoptimistic results, which would then contribute to program failure in practice.

Methods:
A systematic review was undertaken. Two blind reviewers assessed the methodology of relevant publications into a four-point classification system adapted from multiple sources. The association between study design classification and reported results was examined using linear regression with clustering based on screening tool and robust variance estimates with point estimates of Youden Index (= sensitivity + specificity - 1) as the dependent variable. Meta-analysis was then performed pooling data from prospective studies.

Results: Thirty-five publications met inclusion criteria, containing 51 evaluations of fall risk screening tools. Twenty evaluations were classified as retrospective validation evaluations, 11 as prospective (temporal) validation evaluations, and 20 as prospective (external) validation evaluations. Retrospective evaluations had significantly higher Youden Indices (point estimate [95% confidence interval]: 0.22 [0.11, 0.33]). Pooled Youden Indices from prospective evaluations demonstrated the STRATIFY, Morse Falls Scale, and nursing staff clinical judgment to have comparable accuracy.

Discussion: Practitioners should exercise caution in comparing validity of fall risk assessment tools where the evaluation has been limited to retrospective classifications of methodology. Heterogeneity between studies indicates that the Morse Falls Scale and STRATIFY may still be useful in particular settings, but that widespread adoption of either is unlikely to generate benefits significantly greater than that of nursing staff clinical judgment.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

How is the philosophical study of religion best pursued? Responses to this meta-philosophical question tend to recapitulate the analytic-Continental divide in philosophy in general. My aim is to examine the nature of this divide, particularly as it has manifested itself in the philosophy of religion. I begin with a comparison of the stylistic differences in the language of the two traditions, taking the work of Alvin Plantinga and John Caputo as exemplars of the analytic and Continental schools respectively. In order to account for these stylistic divergences, however, it is necessary to delve further into meta-philosophy. I go on to show how each philosophical school models itself on different theoretical practices, the analytic school mimicking the scientific style of inquiry, while in Continental philosophy it is the arts and humanities rather than the sciences that provide the model for philosophical discourse. By situating themselves in such different genres,  analytic and Continental philosophers have developed contrasting, if not mutually exclusive, methods for pursuing the philosophy of religion.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

This thesis represents a part of a program of study that is reaching a closure. The broadest brush that could be applied to my work is that it concerns Physical Education Teacher Education (PETE), that it focuses on aspects of professional socialisation, and that it involves various case studies utilising naturalistic inquiry. Whilst it would be impossible and naive to believe that the reading of these texts will produce the meanings that I encourage, or have internalised, nevertheless the order of reading is at least something that I can argue for. Read in the order I suggest throughout the thesis I am hopeful that my subjectivities, and the learning and understandings I have reached may become clear. The purpose of this two part thesis is an exploration of the interplay or dialectic that exists between PETE students, academic staff and the subject matter within PETE. I have had to come to understand the limitations and advantages of insider research as the work has been completed at my University in the School of Human Movement and Sports Science where I have worked for twenty years. This thesis examines the extent to which studentship and oppositional behaviour underlies the dialectic that exists between the students and the various discourses within the program. I have written the study in two very different formats, one, a collection of stories about PETE and the other, an interpretative case study conducted during 1993 and 1994. Within the case study, studentship and oppositional behaviour were viewed as a measure of the extent to which students react and push against the forces of socialisation within their PETE program that is seen to represent dominant discourses, The following broad research questions were considered to enable the above analysis. 1. What is the nature of studentship and oppositional behaviour in a high status subject within PETE compared to a subject that is seen by students to be of little relevance and of low status? 2. How are studentship and oppositional behaviour related to students subjective warrants? 3. How are the studentship and oppositional behaviours exhibited by students related to the pedagogy and discourses reflected in the knowledge, beliefs and practices within the two sites. The starting point for this research was a study conducted as a totally separate research task (Swan, 1992) that investigated the hierarchies of subject knowledge within a PETE site and investigated the influence of such hierarchies upon student intention. A great deal of meta analysis exists about the manner in which a technocratic rationality pervades PETE but very little case study material of what this means to students and academic staff within such institutions is available. The stories in Between The Rings And Under The Gym Mat, which is the second part of this thesis, represent ‘the data’ differently from the case study, but they speak their own truth. At times the nature of the story is indistinguishable from the reality of the case study. Wexler (1992) undertook an ethnographic study about identity formation in three very different high schools, and published the findings in a book entitled Becoming Somebody. His introductory words about the nature of the social story he tells, are significant to this study and story. Social history is recounted by creative intervention that can only be made from culturally accessible materials. Ethnography is neither an objective realist, nor subjective imaginist account. Rather, it is an historical artefact that is mediated by elaborated distancing of culturally embedded and internally contradictory (but seemingly independent and coherent) concepts that take on a life of their own as theory. So, this is not ‘news from nowhere,’ but a theoretically structured story where both the story and its structure are part of my times. (p.6) The case study before you is organised with an analysis of studentship and oppositional behaviour detailed in chapter one. The following chapter conceptualises studentship and oppositional behaviour in relation to particular themes of professional socialisation, resistance to oppression and youth culture. Chapter three locates the case study to the major paradigmatic debates about the value and nature of the subject matter content within PETE, Chapter four outlines the case site, the research process and the research dilemma’s confronted in this study. The remaining three chapters are the case record as I can best understand it. In Between the Rings and under the Gym Mat (part B) the story most directly concerned with studentship and oppositional behaviour, is called Tale of Two Classes’. It takes on a very different reality to the case study (part A) and much can be said about the reality of lived experience which can be portrayed in narrative form as opposed to a clinical case study. Many of the other stories pose similar images that are contradictory and never quite complete. I have written a separate methodological section for the narrative stories. It is my intention that the case study and the series of stories should be viewed as essentially complementary, but also a discrete representation of a part of PETE. As part of the Ed D program I have undertaken four discrete research tasks as the starting point for this research I have referred to the first one (Hierarchies of Subject knowledge within PETE). I also undertook an action research project about ‘Teaching Poorly by Choice.’ A further piece of research was a somewhat reflective effort to draw together what this has all meant to me from a subjective and reflexive perspective. Such efforts are often seen as being self indulgent, as subjectivity in the form of lived experience sits uneasily in academia. A final paper involved an evaluation of Between the Rings and Under the Gym Mat from a pedagogical perspective by PETE professionals around the world. And that's the way things turned out.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The overarching goal of this dissertation was to evaluate the contextual components of instructional strategies for the acquisition of complex programming concepts. A meta-knowledge processing model is proposed, on the basis of the research findings, thereby facilitating the selection of media treatment for electronic courseware. When implemented, this model extends the work of Smith (1998), as a front-end methodology, for his glass-box interpreter called Bradman, for teaching novice programmers. Technology now provides the means to produce individualized instructional packages with relative ease. Multimedia and Web courseware development accentuate a highly graphical (or visual) approach to instructional formats. Typically, little consideration is given to the effectiveness of screen-based visual stimuli, and curiously, students are expected to be visually literate, despite the complexity of human-computer interaction. Visual literacy is much harder for some people to acquire than for others! (see Chapter Four: Conditions-of-the-Learner) An innovative research programme was devised to investigate the interactive effect of instructional strategies, enhanced with text-plus-textual metaphors or text-plus-graphical metaphors, and cognitive style, on the acquisition of a special category of abstract (process) programming concept. This type of concept was chosen to focus on the role of analogic knowledge involved in computer programming. The results are discussed within the context of the internal/external exchange process, drawing on Ritchey's (1980) concepts of within-item and between-item encoding elaborations. The methodology developed for the doctoral project integrates earlier research knowledge in a novel, interdisciplinary, conceptual framework, including: from instructional science in the USA, for the concept learning models; British cognitive psychology and human memory research, for defining the cognitive style construct; and Australian educational research, to provide the measurement tools for instructional outcomes. The experimental design consisted of a screening test to determine cognitive style, a pretest to determine prior domain knowledge in abstract programming knowledge elements, the instruction period, and a post-test to measure improved performance. This research design provides a three-level discovery process to articulate: 1) the fusion of strategic knowledge required by the novice learner for dealing with contexts within instructional strategies 2) acquisition of knowledge using measurable instructional outcome and learner characteristics 3) knowledge of the innate environmental factors which influence the instructional outcomes This research has successfully identified the interactive effect of instructional strategy, within an individual's cognitive style construct, in their acquisition of complex programming concepts. However, the significance of the three-level discovery process lies in the scope of the methodology to inform the design of a meta-knowledge processing model for instructional science. Firstly, the British cognitive style testing procedure, is a low cost, user friendly, computer application that effectively measures an individual's position on the two cognitive style continua (Riding & Cheema,1991). Secondly, the QUEST Interactive Test Analysis System (Izard,1995), allows for a probabilistic determination of an individual's knowledge level, relative to other participants, and relative to test-item difficulties. Test-items can be related to skill levels, and consequently, can be used by instructional scientists to measure knowledge acquisition. Finally, an Effect Size Analysis (Cohen,1977) allows for a direct comparison between treatment groups, giving a statistical measurement of how large an effect the independent variables have on the dependent outcomes. Combined with QUEST's hierarchical positioning of participants, this tool can assist in identifying preferred learning conditions for the evaluation of treatment groups. By combining these three assessment analysis tools into instructional research, a computerized learning shell, customised for individuals' cognitive constructs can be created (McKay & Garner,1999). While this approach has widespread application, individual researchers/trainers would nonetheless, need to validate with an extensive pilot study programme (McKay,1999a; McKay,1999b), the interactive effects within their specific learning domain. Furthermore, the instructional material does not need to be limited to a textual/graphical comparison, but could be applied to any two or more instructional treatments of any kind. For instance: a structured versus exploratory strategy. The possibilities and combinations are believed to be endless, provided the focus is maintained on linking of the front-end identification of cognitive style with an improved performance outcome. My in-depth analysis provides a better understanding of the interactive effects of the cognitive style construct and instructional format on the acquisition of abstract concepts, involving spatial relations and logical reasoning. In providing the basis for a meta-knowledge processing model, this research is expected to be of interest to educators, cognitive psychologists, communications engineers and computer scientists specialising in computer-human interactions.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

The purpose of instance selection is to identify which instances (examples, patterns) in a large dataset should be selected as representatives of the entire dataset, without significant loss of information. When a machine learning method is applied to the reduced dataset, the accuracy of the model should not be significantly worse than if the same method were applied to the entire dataset. The reducibility of any dataset, and hence the success of instance selection methods, surely depends on the characteristics of the dataset, as well as the machine learning method. This paper adopts a meta-learning approach, via an empirical study of 112 classification datasets from the UCI Repository [1], to explore the relationship between data characteristics, machine learning methods, and the success of instance selection method.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

With the revolution that has taken place in the functionality and uptake of portable networked ‘smart’ technologies, educators are looking to see what potential applications such technologies might have for school education. This article reports on a study into the use of portable personal computing devices in the early years of schooling. Specifically, it focuses on emerging patterns of use of Apple iPads in an Australian Preparatory (first year of compulsory schooling) classroom across the first year of implementation of these devices. We draw on student and teacher interviews and classroom observation data to provide a research meta-narrative of the intentions, practices and reflections of a ‘first year out’ teacher, and to discuss points of tension found in the contested space of early years literacy education, which are highlighted when potentially transformative technologies meet institutionalized literacy education practices. Our findings suggest that the broader policy and curriculum context of early years literacy education, and institutionalized practices found in this space, are potentially at odds with teacher-held intentions to transform learning through technology use, particularly with respect to tensions between print-based traditions and new digital literacies, and those between standards-based classroom curricular and more emancipatory agendas.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

In this response to Mekasha and Tarp (2013) we show that contrary to what they state, their study validates our basic analysis. They confirm that the literature finds that aid is of little economic importance in generating growth. The results also show that the literature systematically selects control variables for their effect on aid effectiveness. We argue that their choice of the random effects model is not appropriate for the problem at hand, and that the way they use multiple meta-regression analysis contradicts the robust results reached at the basic analysis.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Physical activity is important for preventing weight gain and obesity, but women experiencing socioeconomic disadvantage are at high risk of inactivity. This study aimed to determine the effectiveness of interventions to increase physical activity among women experiencing disadvantage, and the intervention factors (i.e. physical activity measure, delivery mode, delivery channel, setting, duration, use of theory, behavioural techniques, participant age, risk of bias) associated with effectiveness. We conducted a meta-analysis of controlled trials using random-effects models and meta-regression. Seven databases were searched for trials among healthy women (18–64 years), which included a physical activity intervention, any control group, and statistical analyses of a physical activity outcome at baseline and post-intervention. Nineteen studies were included (n = 6,339). Because of substantial statistical heterogeneity (χ2 = 53.61, df = 18, P < 0.0001, I2 = 66%), an overall pooled effect is not reported. In subgroup analyses, between-group differences were evident for delivery mode, which modestly reduced heterogeneity (to 54%). Studies with a group delivery component had a standardized mean difference of 0.38 greater than either individual or community-based delivery. Programs with a group delivery mode significantly increase physical activity among women experiencing disadvantage, and group delivery should be considered an essential element of physical activity promotion programs targeting this population group.

Relevância:

30.00% 30.00%

Publicador:

Resumo:

Aims and objectives : To compare the efficacy of chronic heart failure management programmes (CHF-MPs) according to a scoring algorithm used to quantify the level of applied interventions–the Heart Failure Intervention Score (HF-IS).

Background :
The overall efficacy of heart failure programmes has been proven in several meta-analyses. However, the debate continues as to which components are essential in a heart failure programme to improve patient outcomes.

Design : Prospective cohort study of patients participating in heart failure programmes.

Method :
Forty-eight of 62 (77%) programmes in Australia participating in a national register of CHF-MPs were evaluated using the HF-IS: derived from a summed and weighted score of each intervention applied by the CHF-MP (27 interventions overall). The CHF-MPs were prospectively categorised as relatively low (HF-IS < 190 – n = 39 programmes & 407 patients) or high (HF-IS ≥ 190 – n = 9 programmes & 166 patients) in complexity. Six-month morbidity and mortality rates in 573 consecutively recruited patients with systolic dysfunction and in New York Heart Association Class II–IV were prospectively examined.

Results : Patients exposed to CHF-MPs with a high HF-IS had a lower rate of unplanned, all-cause hospitalisation (n = 24, 14% vs. n = 102, 25%) compared with CHF-MPs with a low HF-IS within six months. On an adjusted basis, CHF-MPs with a high HF-IS were associated with a reduced risk of unplanned hospitalisation and/or death within six months and remained event-free longer.

Conclusion :
High complexity CHF-MPs applying more evidence-based interventions are associated with a higher event-free survival over six months.

Relevance to clinical practice : The HF-IS is an easy-to-use evidence-based tool to assist programme coordinators to improve the quality of their heart failure programme which may also improve patient outcomes.