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关键词： First-Year Undergraduate/General   Student-Centered Learning   Curriculum   Collaborative/Cooperative Learning   Minorities in Chemistry   Broadening Participation   Inclusive Teaching  

摘要： US colleges and universities have known for decades that higher percentages of racial and ethnic subgroups leave STEM majors, contributing to racial inequality in STEM professions. Many interventions have been developed, yet the disparity persists. A partial flipped pedagogical model is presented for a General Chemistry 1 (GChem1) course that is delivered in a team learning format (PFTL). In the PFTL classroom, students are placed in diverse teams of 5-6 students who then work through activities and quizzes to engage with the material and to identify misconceptions. Using a Socratic lecture format as a baseline, students experiencing the PFTL format were less likely to withdraw and more likely to achieve grades sufficient to progress toward degree completion. The success of BIPOC and non-BIPOC groups using PFTL became evident by disaggregating BIPOC into subpopulations. PFTL instruction resonated with non-BIPOC and Black/African American (B/AA) students, who posted the greatest increases in course retention and overall success. The LatinX student response was more modest. LatinX withdrawals declined by 8% points compared to double-digit declines for non-BIPOC and B/AA students (14 and 33, respectively). Additionally, LatinX student success increased primarily in the C/D categories while B/AA and non-BIPOC student gains were in B/C categories. Overall, PFTL instruction supports student completion in GChem1. A deeper understanding of the student, faculty, and society perspectives that are driving these results will help to address the persistent grade disparity within STEM education.

关键词： Bioinformatics   Microarrays   Computational Biology/Bioinformatics   Computer Appl. in Life Sciences   Algorithms  

摘要： Background DNA methylation has long been known as an epigenetic gene silencing mechanism. For a motivating example, the methylomes of cancer and non-cancer cells show a number of methylation differences, indicating that certain features characteristics of cancer cells may be related to methylation characteristics. Robust methods for detecting differentially methylated regions (DMRs) could help scientists narrow down genome regions and even find biologically important regions. Although some statistical methods were developed for detecting DMR, there is no default or strongest method. Fisher's exact test is direct, but not suitable for data with multiple replications, while regression-based methods usually come with a large number of assumptions. More complicated methods have been proposed, but those methods are often difficult to interpret. Results In this paper, we propose a three-step nonparametric kernel smoothing method that is both flexible and straightforward to implement and interpret. The proposed method relies on local quadratic fitting to find the set of equilibrium points (points at which the first derivative is 0) and the corresponding set of confidence windows. Potential regions are further refined using biological criteria, and finally selected based on a Bonferroni adjusted t-test cutoff. Using a comparison of three senescent and three proliferating cell lines to illustrate our method, we were able to identify a total of 1077 DMRs on chromosome 21. Conclusions We proposed a completely nonparametric, statistically straightforward, and interpretable method for detecting differentially methylated regions. Compared with existing methods, the non-reliance on model assumptions and the straightforward nature of our method makes it one competitive alternative to the existing statistical methods for defining DMRs.

关键词： 导数   边际分析  

摘要： 在西方现代经济学中,为了让经济分析方法更加简便、更加方便,我们引入了一些数学方法,例如边际分析法,弹性分析法等等.在诸多方法中,边际分析法的运用最为广泛.边际分析最开始的时候是用于企业的价值分析,之后被广泛的运用到企业的成本、企业的收入、企业的利润和企业的代替率等等方面.那么边际到底是什么呢?边际主要是在"增加的""额外的"基础上使用的,是用来考察当某一经济量增加之后,它增加的部分对其它相关量的增量之间的关系与影响.这也是数学微分学研究的问题.因此,用数学方法研究经济学中的边际问题,形成边形分析方法是很自然的事.