5,381 research outputs found

    Applying Argumentation Analysis to Assess the Quality of University Oceanography Students' Scientific Writing

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    This article describes the methods and results of an assessment of students' scientific writing. The study was conducted in an introductory oceanography course in a large public university that used an interactive CD-ROM entitled, "Our Dynamic Planet." The CD provided students with geological data, which they used to build written arguments regarding plate tectonics. Twenty-four student papers from this course were analyzed for quality of written arguments by using both a grading rubric and an argumentation analysis model. Three implications were drawn from these initial studies. First, there is a clear need to help students understand how to use data representations as evidence for more theoretical arguments. Second, student writers need experiences receiving critiques of their own writing and analyzing others' scientific arguments. Third, the actual grading is dependent upon the socialization of the graders themselves (in this case, graduate students). Educational levels: Graduate or professional

    Simple Computational Methods for Measuring the Difference of Empirical Distributions: Application to Internal and External Scope Tests in Contingent Valuation

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    This paper develops a statistically unbiased and simple method for measuring the difference of independent empirical distributions estimated by bootstrapping or other simulation approaches. This complete combinatorial method is compared with other unbiased and biased methods that have been suggested in the literature, first in Monte Carlo simulations and then in a field test of external and internal scope testing in contingent valuation. Tradeoffs between methods are discussed. When the empirical distributions are not independent a straightforward difference test is suggested.Research Methods/ Statistical Methods,

    Sliding Doors Cost Measurement A Restrictive Approach to Analyzing the Net Economic Cost of Policy Decisions

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    This paper develops a restrictive procedure for evaluating economic policy decisions, by comparing actual economic history to a simulated history where a specific policy decision is replaced with a counterfactual, but credible, alternative. Our procedure is theoretically straightforward, but empirically problematic since it requires the identification of a feasible policy alternative and a model linking a specific policy choice to subsequent economic outcomes. We apply the procedure to the mistaken decision to maintain an excessively lax financial regulation regime in Ireland during the period 2003 – 2008. We measure the differences in banking sector stability and national income that would have occurred if the stricter regulatory regime imposed in Ireland in 2009 had been put in place six years earlier. We find that a few simple, reasonably prudent regulatory controls on the Irish banking sector would have greatly limited the vulnerability of the domestic sector to the 2008 global credit freeze, and almost certainly prevented the 2008-2009 collapse of the domestic banking sector and the consequent deep Irish recession of 2009-2010. On the other hand, the risky and unsustainable inflow of foreign capital mediated by the domestic banks accounts for a substantial part of Irish economic growth during the 2003-2007 period. Without this net foreign borrowing inflow, cumulative gross domestic product over the early period would have been substantially lower. * W

    Frizzled gene expression and negative regulation of canonical WNT-β-catenin signaling in mouse F9 teratocarcinoma cells

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    Mouse F9 cells differentiate into primitive endoderm (PrE) following the activation of the canonical WNT-β-catenin pathway. The upregulation of Wnt6 and activation of β-catenin-TCF-LEF-dependent transcription is known to accompany differentiation, but the Frizzled (FZD) receptor responsible for transducing the WNT6 signal is not known. Eight of the 10 Fzd genes were found to be expressed in F9 cells, with Fzd7 being the most highly expressed, and chosen for further analysis. To alter steady-state Fzd7 levels and test the effect this has on differentiation, siRNA and overexpression approaches were used to knock-down and ectopically express the Fzd7 message, respectively. siRNA knock-down of Fzd7 resulted in reduced DAB2 levels, and the overexpression activated a TCF-LEF reporter, but neither approach affected differentiation. Our focus turned to how canonical WNT6 signaling was attenuated to allow PrE cells to form parietal endoderm (PE). Dkk1, encoding a WNT antagonist, was examined and results showed that its expression increased in F9 cells treated with retinoic acid (RA) or overexpressing Wnt6. F9 cells overexpressing human DKK1 or treated with DKK1-conditioned medium and then treated with RA failed to differentiate, indicating that a negative feedback loop involving WNT6 and DKK1 attenuates canonical WNT-β-catenin signaling, thereby allowing PE cells to differentiate

    The Gel Documentation System: A Cornerstone to the Implementation of the Introduction to Biotechnology and Introduction to Bioinformatics Cross-Disciplinary Course Series (FINAL REPORT)

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    Our original goal was to offer Pace undergraduate students opportunities to be introduced to both Biotechnology and Computer Science as it relates to Bioinformatics. We proposed a two course series, offered to both computer science and biology students that will increase both biological and computer science literacy of our students. The two courses are Introduction to Biotechnology (BIO 372) and Introduction to Bioinformatics

    Mechanisms Regulating Stemness and Differentiation in Embryonal Carcinoma Cells

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    Just over ten years have passed since the seminal Takahashi-Yamanaka paper, and while most attention nowadays is on induced, embryonic, and cancer stem cells, much of the pioneering work arose from studies with embryonal carcinoma cells (ECCs) derived from teratocarcinomas. This original work was broad in scope, but eventually led the way for us to focus on the components involved in the gene regulation of stemness and differentiation. As the name implies, ECCs are malignant in nature, yet maintain the ability to differentiate into the 3 germ layers and extraembryonic tissues, as well as behave normally when reintroduced into a healthy blastocyst. Retinoic acid signaling has been thoroughly interrogated in ECCs, especially in the F9 and P19 murine cell models, and while we have touched on this aspect, this review purposely highlights how some key transcription factors regulate pluripotency and cell stemness prior to this signaling. Another major focus is on the epigenetic regulation of ECCs and stem cells, and, towards that end, this review closes on what we see as a new frontier in combating aging and human disease, namely, how cellular metabolism shapes the epigenetic landscape and hence the pluripotency of all stem cells
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