New physics searches at the BESⅢ experiment

The standard model (SM) of particle physics,comprised of the unified electroweak and quantum chromodynamic theories,accurately explains almost all experimental ...     

Finding Fruit on the Vines: Using Higher Education Research and Institutional Research to Guide Institutional Policies and Strategies

This is the first of two articles that examine the utility of higher education research to help guide campus-based interventions to enhance institutional effectiveness. This first article describes the organizational context and sequence of events, which set the stage for the interventions that were implemented at this public research university. It next delineates the interventions implemented in areas related to enrollment management. Finally, the first article describes the effects of these interventions. The second article, which follows immediately in this issue, outlines programmatic efforts undertaken to enhance the quality of the first-year experience for new students.     

Micromixing visualization and quantification in a microscale multi-inlet vortex nanoprecipitation reactor using confocal-based reactive micro laser-induced fluorescence

A technique for visualizing and quantifying reactive mixing for laminar and turbulent flow in a microscale chemical reactor using confocal-based microscopic laser induced fluorescence (confocal μ-LIF) was demonstrated in a microscale multi-inlet vortex nanoprecipitation reactor. Unlike passive scalar μ-LIF, the reactive μ-LIF technique is able to visualize and quantify micromixing effects. The confocal imaging results indicated that the flow in the reactor was laminar and steady for inlet Reynolds numbers of 10, 53, and 93. Mixing and reaction were incomplete at each of these Reynolds numbers. The results also suggested that although mixing by diffusion was enhanced near the midplane of the reactor at Re_j = 53 and 93 due to very thin bands of acidic and basic fluid forming as the fluid spiraled towards the center of the reactor, near the top, and bottom walls of the reactor, the lower velocities due to fluid friction with the walls hindered the formation of these thin bands, and, thus, resulted in large regions of unmixed and unreacted fluid. At Re_j = 240, the flow was turbulent and unsteady. The mixing and reaction processes were still found to be incomplete even at this highest Reynolds number. At the reactor midplane, the flow images at Re_j = 240 showed unmixed base fluid near the center of the reactor, suggesting that just as in the Re_j = 53 and 93 cases, lower velocities near the top and bottom walls of the reactor hinder the mixing and rection of the acidic and basic streams. Ensemble averages of line-scan profiles for the Re_j = 240 were then calculated to provide statistical quantification of the microscale mixing in the reactor. These results further demonstrate that even at this highest Reynolds number investigated, mixing and reaction are incomplete. Visualization and quantification of micromixing using this reactive μ-LIF technique can prove useful in the validation of computational fluid dynamics models of micromixing within microscale chemical reactors.     

Learning about students’ knowledge and thinking in science through large-scale quantitative studies

The main issue addressed in this article is that there is much to learn about students’ knowledge and thinking in science from largescale international quantitative studies beyond overall score measures. Response patterns on individual or groups of items can give valuable diagnostic insight into students’ conceptual understanding, but there is also a danger of drawing conclusions that may be too simple and nonvalid. We discuss how responses to multiple-choice items could be interpreted, and we also show how responses on constructed-response items can be systematised and analysed. Finally, we study, empirically, interactions between item characteristics and student responses. It is demonstrated that even small changes in the item wording and/or the item format may have a substantial influence on the response pattern. Therefore, we argue that interpretations of results from these kinds of studies should be based on a thorough analysis of the actual items used. We further argue that diagnostic information should be an integrated part of the international research aims of such large-scale studies. Examples of items and student responses presented are taken from The Third International Mathematics and Science Study (TIMSS).     

Aztec Middle College: High School Alternatives in Community Colleges

The traditional high school model derived from the factory deficit model of the early 1900s has left many students, mainly minorities and/or low socioeconomic students, disenfranchised. This is evident in the poor school performance and high dropout rates of such students. Whereas the factory deficit model was created to promote only a few high school students to college, the rest of the students were trained for factory jobs. Today's job market requires that high school students go to college subsequent to their graduation. For this reason, middle college alternatives to traditional high schools are being adopted. Although research on middle colleges is limited due to their recent development, the results are encouraging: high school students who would otherwise have failed school or dropped out have high attendance rates and high graduation rates.     

AFFINITY DISCIPLINES AND THE USE OF PRINCIPLES OF GOOD PRACTICE FOR UNDERGRADUATE EDUCATION

Academic disciplines with soft paradigmaticdevelopment tend to have an affinity for more readilyenacting practices designed to improve undergraduateeducation than do hard paradigmatic developmentdisciplines. This study extends the affinity disciplinehypothesis to Chickering and Gamson's seven principlesof good practice. The affinity discipline hypothesisgarners empirical support for four of the sevenprinciples of good practice: encouragement offaculty-student contact, encouragement of activelearning, communication of high expectations, andrespect for diverse talents and ways of knowing.Implications for theory and practice are suggested by the findings ofthis study.     

Transformative graduate education programs: an analysis of impact on STEM and non-STEM Ph.D. completion

Transformative graduate education programs (TGP) are programs that are national in scope and are intended to impact the reformation of graduate education in the United States. We employ data from national sources and shift the unit of analysis from the individual doctoral student to the doctoral institution as whole in order to begin to assess the impact of TGPs on the number of doctoral degrees awarded, a critical outcome for such programs, and an educational priority in many countries. In addition, we examine the critical issue of whether TGPs enhance Ph.D. degree conferral for women and minorities, and if they do so at STEM-oriented institutions, typically the least hospitable of all environments for these groups.