Browsing by Subject "Meta-Analysis"

Now showing 1 - 4 of 4
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    The role of social class models in the relationship between socioeconomic status and academic achievement.
    (2009-05) Lee, Kyoungwon
    Educational models of achievement almost always include SES measures but these measures are typically selected in an atheoretical way. Using social class theories to conceptualize SES in a study and to help select SES measures should enhance the credibility of inferences. The social class theory literature was reviewed and used to identify SES measures consistent with particular theories. The reviewed social class theories were Weberian, Marxian and Occupationalist theories and SES measures consistent with these theories were income, education, and occupation, respectively. A meta-analysis was used to provide an empirical test of the effect of selecting SES measures in a theoretically grounded way on the relationship between SES and achievement. The results indicated that there were small differences favoring the theoretically grounded measures. The importance of educational researchers turning to the social class literature for guidance in conceptualizing and measuring SES is discussed.
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    Systems Engineering of Stem Cell Fate
    (2015-08) Raju, Ravali
    Recent advances in the derivation of functional cells from pluripotent stem cells have raised hope for cell therapy to treat liver ailments. They have enhanced the prospects of developing reliable in vitro models for liver diseases and drug toxicity screening. A differentiation protocol mimicking key signaling cues of embryonic development was developed to direct stem cells (ES) towards the hepatic fate and express key hepatic markers and functions. While these results are encouraging, most directed differentiations from stem cells to the target cell types are hampered by lack of functional maturity, cell heterogeneity and low cell yields limiting their translation to the clinic. These cells are therefore refereed to hepatocyte-like cells (HLCs). An integrative strategy was employed including both experimental techniques as well as a systems-based analysis towards enhancing the product quality and yields of HLCs. Functional maturity was enhanced by initiating three dimensional spheroid formation upon differentiation. Enrichment of hepatic cells using selective medium conditions was performed to obtain higher fraction of cells with the desired properties. Cell expansion was incorporated during differentiation to improve cell yields. Several additional strategies have been used to increase hepatocyte maturity in literature including co-culture and transfection with transcription factors. These methods including ours have shown improvement, however a universal gap to maturation is still present when compared to primary hepatocytes. Comparison of transcriptome data of differentiation to embryonic liver development can elucidate the genetic roadblocks preventing ES cells from reaching the functional maturity of their tissue counterparts. Transcriptome data was compiled from various depositories for mouse fetal liver development (from E8.5 to post-natal). Transcriptome data was obtained during the time course of our human hepatic differentiation protocol and was augmented with human in vitro hepatic differentiation data in the public depository. Interestingly, majority of the HLCs are similar irrespective of the cell source and protocol. The entire cohort of HLCs clustered separately from the primary hepatocytes and adult liver indicating an inherent roadblock to maturation. The transcriptome data of human ES hepatic differentiations was then integrated with mouse liver development using a unique approach. This allowed us to identify the corresponding development stage at which the in vitro stem cell differentiation is blocked. The analysis uncovered a pivotal gene set with contrasting profiles in ES differentiation and mouse liver development that merit combinatorial genetic intervention to enhance maturation of ES derived hepatocytes. Thus, one can envision the availability of stem cell based liver therapies in the not so distant future.
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    Use of Recommended Search Strategies in Systematic Reviews and the Impact of Librarian Involvement: A Cross-Sectional Survey of Recent Authors
    (PLOS ONE, 2015-05-04) Koffel, Jonathan
    Background: Previous research looking at published systematic reviews has shown that their search strategies are often suboptimal and that librarian involvement, though recommended, is low. Confidence in the results, however, is limited due to poor reporting of search strategies the published articles. Objectives: To more accurately measure the use of recommended search methods in systematic reviews, the levels of librarian involvement, and whether librarian involvement predicts the use of recommended methods. Methods: A survey was sent to all authors of English-language systematic reviews indexed in the Database of Abstracts of Reviews of Effects (DARE) from January 2012 through January 2014. The survey asked about their use of search methods recommended by the Institute of Medicine, Cochrane Collaboration, and the Agency for Healthcare Research and Quality and if and how a librarian was involved in the systematic review. Rates of use of recommended methods and librarian involvement were summarized. The impact of librarian involvement on use of recommended methods was examined using a multivariate logistic regression. Results: 1560 authors completed the survey. Use of recommended search methods ranged widely from 98% for use of keywords to 9% for registration in PROSPERO and were generally higher than in previous studies. 51% of studies involved a librarian, but only 64% acknowledge their assistance. Librarian involvement was significantly associated with the use of 65% of recommended search methods after controlling for other potential predictors. Odds ratios ranged from 1.36 (95% CI 1.06 to 1.75) for including multiple languages to 3.07 (95% CI 2.06 to 4.58) for using controlled vocabulary. Conclusions: Use of recommended search strategies is higher than previously reported, but many methods are still under-utilized. Librarian involvement predicts the use of most methods, but their involvement is under-reported within the published article.
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    When and How Do Message Matching Interventions Work? Exploring Principles to Guide the Use of Message Matching Through a Systematic Review and Meta-analysis, and an Experimental Study
    (2020-08) Joyal-Desmarais, Keven
    One of the most common techniques behavioral scientists use to influence people’s attitudes, intentions, and behaviors is message matching—the systematic design and distribution of persuasive messages such that their features (e.g., themes emphasized) are maximally congruent with the characteristics (e.g., motives) of their audience. Despite its popularity, the effectiveness of the technique varies greatly, and there are few established principles on how to best use it. My dissertation addresses this gap through a theoretical review and two empirical projects. The theoretical review summarizes four distinct literatures that use message matching (functional matching, message framing, message tailoring, and context matching), and proposes several principles. For example, I argue that messages vary along a continuum from positive matches (that are congruent with a person’s motivations) to negative matches (that are in opposition to people’s motivations), and that the success of interventions depends on both achieving positive matches and avoiding negative matches. I also discuss how targeting certain types of characteristics (e.g., motivational orientations) should lead to stronger effects than targeting other characteristics (e.g., demographics). Project 1 presents results from an ongoing registered systematic review (PROSPERO CRD42019116688; osf.io/rpjdg) that explores these principles. A three-level meta-analysis of 604 experimental functional matching studies (covering 4,228 effect size estimates) finds that matching messages to motivationally-relevant characteristics leads to effects around r = .20 on attitudes, intentions, and behaviors. The results demonstrate larger effects than works focused on matching to less motivationally focused characteristics (e.g., demographics), and provide evidence that avoiding negative matching while achieving positive matching leads to larger effects than achieving positive matching alone. These comparative inferences, however, depend on correlational differences between matching studies. Project 2 therefore complements the meta-analysis by presenting a registered (osf.io/yqmsd) experiment (N = 1,101) that directly evaluates the relative effects of positively and negatively matched messages (as these compare to neutral messages), in the context of promoting a non-profit organization by targeting people’s political orientation. The results show that both positive matches and negative matches impact persuasion, but that the detrimental effects of negative matches are greater than the beneficial effects of positive matches.