Marcy P. Osgood

Microbial Community Responses to Atmospheric Carbon Dioxide Enrichment in a Warm-Temperate Forest

Forest productivity depends on nutrient supply, and sustained increases in forest productivity under elevated carbon dioxide (CO2) may ultimately depend on the response of microbial communities to changes in the quantity and chemistry of plant-derived substrates, We investigated microbial responses to elevated CO2 in a warm-temperate forest under free-air CO2 enrichment for 5 years (1997–2001). The experiment was conducted on three 30 m diameter plots under ambient CO2 and three plots under elevated CO2 (200 ppm above ambient). To understand how microbial processes changed under elevated CO2, we assayed the activity of nine extracellular enzymes responsible for the decomposition of labile and recalcitrant carbon (C) substrates and the release of nitrogen (N) and phosphorus (P) from soil organic matter. Enzyme activities were measured three times per year in a surface organic horizon and in the top 15 cm of mineral soil. Initially, we found significant increases in the decomposition of labile C substrates in the mineral soil horizon under elevated CO2; this overall pattern was present but much weaker in the O horizon. Beginning in the 4th year of this study, enzyme activities in the O horizon declined under elevated CO2, whereas they continued to be stimulated in the mineral soil horizon. By year 5, the degradation of recalcitrant C substrates in mineral soils was significantly higher under elevated CO2. Although there was little direct effect of elevated CO2 on the activity of N- and P-releasing enzymes, the activity of nutrient-releasing enzymes relative to those responsible for C metabolism suggest that nutrient limitation is increasingly regulating microbial activity in the O horizon. Our results show that the metabolism of microbial communities is significantly altered by the response of primary producers to elevated CO2. We hypothesize that ecosystem responses to elevated CO2 are shifting from primary production to decomposition as a result of increasing nutrient limitation.

Comparison of student performance in cooperative learning and traditional lecture-based biochemistry classes.

Student performance in two different introductory biochemistry curricula are compared based on standardized testing of student content knowledge, problem‐solving skills, and student opinions about the courses. One curriculum was used in four traditional, lecture‐based classes (n = 381 students), whereas the second curriculum was used in two cooperative learning classes (n = 39 students). Students in the cooperative learning classes not only performed at a level above their peers in standardized testing of content knowledge and in critical thinking and problem‐solving tasks (p < 0.05), but they also were more positive about their learning experience. The testing data are in contrast to much of the medical school literature on the performance of students in problem‐based learning (PBL) curricula, which shows little effect of the curricular format on student exam scores. The reason for the improvement is undoubtedly multifactorial. We argue that the enhancement of student performance in this study is related to: 1) the use of peer educational assistants, 2) an authentic PBL format, and 3) the application of a multicontextual learning environment in the curricular design. Though educationally successful, the cooperative learning classes as described in this study were too resource intensive to continue; however, we are exploring incorporation of some of the “high context” aspects of the small‐group interactions into our current lecture‐based course with the addition of on‐line PBL cases.

Lessons learned from a study-group pilot program for medical students perceived to be ‘at risk’

Background: At the University of New Mexico School of Medicine (UNM-SOM) we have noticed that some first year medical students have difficulty accurately assessing their academic skills and are often afraid to seek help. This leads to marginal performance and sometimes even failure. Therefore, we developed a preemptive intervention using peer-led study groups based on the personalized System of Instruction (PSI). Aim: The goal of this pilot study was to evaluate this approach for assisting students, interms of student success, and cast benefit. Methods: Thirteen first-year medical students considered to be ‘at risk’ of academic difficulty took part in a six-month pilot intervention. They participated in structured study groups that were facilitated by upper-level medical students. The groups met twice weekly for up to two hours each time. The at-risk students took short multiple-choice quizzes and discussed major concepts. If students did not achieve 80% or better on the quizzes, they were required to take a second quiz to demonstrate mastery. Summative exam scores from four groups of students were compared: those with Medical College Admission Test (MCAT) scores <25, who received the study group intervention; their classmates with MCAT scores >25 who did not receive the intervention; and two matched groups from the previous year, none of whom had access to the structured study groups. Results: No significant differences in exam scores were seen between the group who received the intervention and the matched group who did not. Conclusions: Despite this result, we learned several useful lessons about study groups and interactions between first-year and upper-level medical students: (1) Students perceived participation in the study groups as a good learning strategy, but preferred participation not be mandated. It may be preferable to train and encourage students to run their own study groups. (2) Both students and proctors acknowledged interpersonal benefits from the program but, as these benefits can be achieved by other means, an expensive proctor-based program is not, we believe, the best use of academic support resources. (3) Focus in the study groups was on content for the quizzes, but more attention to how-to-learn strategies may have had greater impact.

Teachers as learners in a cooperative learning biochemistry class

Upper level college students majoring in biochemistry at the University of New Mexico have the opportunity to participate in an advanced biochemistry course entitled “Biochemistry Education.” This course introduces theories of teaching and learning, provides opportunities for participation in course organization, design, and assessment strategies, and requires practice in lecturing, exam writing, and grading. One component of this course required the biochemistry majors to act as educational assistants, leading problem‐based learning sessions in a cooperative learning introductory survey biochemistry course for nonmajors. Problem‐based learning scenarios used in this course were based on real‐life biochemistry problems. As a result of their participation, the educational assistants increased their understanding of the biochemistry principles, gained an appreciation for the difficulty of the job of a “good teacher,” developed new approaches to their own learning, and became more confident speakers. The participating biochemistry faculty were also positively affected by the collaborative approach they were attempting to model for the two sets of students and realized the benefits of truly cooperative team teaching.

A research-based laboratory course designed to strengthen the research-teaching nexus.

We describe a 10‐week laboratory course of guided research experiments thematically linked by topic, which had an ultimate goal of strengthening the undergraduate research‐teaching nexus. This undergraduate laboratory course is a direct extension of faculty research interests. From DNA isolation, characterization, and mutagenesis, to protein expression and structural analysis, the research protocols were adapted to suit the weekly 3‐hour biochemistry course. The experiments described are flexible and hypothesis driven, allowing original research to be conducted. Students gain practice in some of the most common techniques used in biochemistry and molecular biology, including minipreps and DNA spectrophometric analysis, DNA restriction digestion and agarose gel electrophoresis, PCR mutagenesis, DNA sequencing analyses, E. coli transformations, whole cell protein extractions, SDS‐PAGE, immunoblots, molecular modeling, and bioinformatics. The studies that begun in the classroom were continued in the research laboratory by undergraduate students, and eventually, the results were published in peer reviewed research articles. This research‐educational program effectively integrated basic research endeavors into the undergraduate curriculum. It proved to be synergistic by nature: research stimulated teaching and teaching supported research. In our experience, this is an effective mechanism to conduct productive research while satisfying teaching duties in undergraduate institutions, where scholarly research is expected but teaching is the primary mission.

PULSE Vision & Change Rubrics

Dear Editor: We want to inform CBE—Life Sciences Education readers about the release of the first version of the Partnership for Undergraduate Life Sciences Education (PULSE) Vision & Change Rubrics (available at the PULSE Community website: www.pulsecommunity.org). These rubrics were written and assembled by the PULSE Vision & Change Leadership Fellows to help stimulate the widespread adoption of the principles outlined in the 2011 National Academy of Sciences report Vision and Change in Undergraduate Biology Education: A Call to Action (American Association for the Advancement of Science [AAAS], 2011 ). Initially, these rubrics can be utilized for departmental self-assessment. In the longer term, the rubrics are intended serve as the basis of a tiered certification program for life sciences departments based on Vision and Change principles. In 2006, the National Science Foundation (NSF) initiated a multi-year conversation with the undergraduate life sciences community, with assistance from the AAAS. That conversation, cosponsored by the National Institutes of Health/National Institute of General Medical Sciences (NIH/NIGMS) and the Howard Hughes Medical Institute (HHMI), resulted in the release of the Vision and Change report in 2011 (AAAS, 2011 ). Among the recommendations in the Vision and Change report was recognition that a 21st-century education requires modifications of faculty incentive systems, academic departmental support, how curricular decisions are determined, and biology education pedagogy. In 2012, the NSF, NIH/NIGMS, and HHMI founded the Partnership for Undergraduate Life Sciences Education, or PULSE, to catalyze implementation of Vision and Change principles across all institutions of higher education. The PULSE community, open to all life sciences educators, now hosts more than 1000 members. Forty Vision and Change Leadership Fellows selected from among biologists with leadership roles at institutions of higher education of all types were charged with developing strategies to promote systemic changes in life sciences education. The PULSE initiative is intended to catalyze change at the departmental and institutional levels by initiating and implementing new strategies to assist departments and institutions to move toward a shared vision and effect curricular transformation (Manning, 2013 ). Decisions regarding curriculum, hiring, teaching assignments, faculty evaluations, mentoring, and faculty development are typically made at the department level. Thus, a concerted effort at this level is needed to overcome the widespread resistance to change (Savkar and Lokere, 2010 ; Anderson et al., 2011 ). During the past year, the 40 PULSE Leadership Fellows have designed and begun to implement several initiatives to facilitate educational transformation in life sciences departments. One of these initiatives, the PULSE Vision & Change Rubrics, is described briefly here. The PULSE Vision & Change Rubrics articulate fundamental criteria for evaluating the level and degree of departmental adoption of the principles of Vision and Change. These rubrics assess department or program alignment with Vision and Change recommendations in five broad areas: curriculum alignment, assessment, faculty practice/faculty support, infrastructure, and climate for change. Each rubric has several categories with multiple criteria to be assessed (see Figure 1 for a sample rubric). The rubric descriptors designate different levels of implementation of Vision and Change principles from first steps to full departmental transformation. The set of rubrics has been designed for flexible use by undergraduate life sciences departments at a broad range of institution types including 2-yr colleges, 4-yr liberal arts institutions, regional comprehensive institutions, and research institutions. Figure 1. Sample from the PULSE Vision & Change Rubrics. The rubrics are organized with separate criteria listed on the left, with levels of achievement across the top, from zero (no achievement) to four (exemplary achievement). In total, 69 separate criteria ... We expect that the PULSE Vision & Change Rubrics will be used for a variety of purposes, including departmental self-assessment, engagement of senior academic administrators, and as the basis for a departmental certification program. Initially, the rubrics can provide a structure and “road map” for departmental reflection regarding a host of topics relevant to implementation of Vision and Change recommendations. A goal of the rubrics is to provide a basic framework of expectations, such that evidence of adoption of Vision and Change principles can be gathered and self-assessed by departments and a road map for continued transformation can be charted. We anticipate that the rubrics themselves can serve as an assessment tool to examine how changes in departmental practices over time affect student outcomes. Longer term, we intend the rubrics to serve as the basis for a tiered certification program for undergraduate life sciences departments that have adopted some or all of the principles outlined in the Vision and Change report. Certification will serve both to reward departments that have made substantial progress in implementing Vision and Change, and to incentivize departments that have been slow to adopt these changes. An underlying assumption of the PULSE Vision & Change Rubrics is that higher scores resulting from excellent/exemplar level of achievement will result in better student outcomes. At present, this is only a hypothesis, and we and others who use the rubrics will gather data to test this hypothesis. This evidence will guide future revisions of the PULSE Vision & Change Rubrics, to ensure that they reflect the criteria that “really matter” to improve student learning. We are very interested in receiving feedback from the biology education community. This is most easily done via the PULSE Community website or by contacting one of the authors directly. During the past year of development, we have done our best to include the most relevant criteria for capturing and recognizing departmental efforts, but it is likely we have omitted key items or areas. We are depending on the community to provide feedback so as to make the rubrics as effective as possible. We anticipate that the rubrics will be revised over the next year, and we expect them to evolve in future years based on evidence of their effectiveness and changing standards of knowledge and practice in undergraduate life sciences education.

Self or help? A comparison of a personalized system of instruction biochemistry class to a standard lecture‐based biochemistry class

For the past eight years the University of Michigan has offered two different styles of biochemistry courses each semester, one a standard lecture‐based and discussion‐section (SLB) course and one a self‐paced, non‐lecture Personalized System of Instruction (PSI) course. We tracked student responses to selected exam questions that were used in both courses for three semesters. Data on student grade point average, student satisfaction, and perceived effort in the courses were also gathered. In two of the three semesters that we monitored students there were no significant differences in performance on test questions between the two courses. In one of the three semesters there was a small but nevertheless significant difference between the two courses with junior and senior PSI students outperforming their SLB counterparts by 10 points. Student grade point average, overall satisfaction, and perceived effort were similar for both courses. Our study indicated that the PSI format works as well as the SLB model does for students in biochemistry and may be especially beneficial for more experienced students.

Undergraduate Performance in Solving Ill-Defined Biochemistry Problems

This mixed-methods study retrospectively examines the competency of graduating biochemistry majors in areas related to scientific process, including the abilities to generate hypotheses, design experiments, evaluate data, draw conclusions, and reflect upon performance.

Commentary: PhDs in biochemistry education—5 years later

In this commentary, the discussion of PhDs in biochemistry education research is expanded to explore a number of diverse pathways leading to a competitive research program in biochemistry education research.