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In order to support physics students in their future careers, there is a need to understand the relationship between undergraduate education and professional practice in physics-related fields. This study investigated high-level goal driven mathematical problem-solving activities that are found within two disciplinary cultures: physical science research labs in academia and photonics workplaces in industry. We conducted semistructured interviews with 10 Ph.D. students and 22 engineers and technicians. Math use in professional workplaces was characterized through an adaptation of epistemic games framework, which revealed six common epistemic games in these workplaces: conceptual math modeling, analytical-numerical math modeling, design-oriented math modeling, fabrication, improving processes, and making meaning out of data games. The workplace-specific epistemic games capture the goals, starting and ending conditions, constraints and contextual features, moves, tools, and representations. The games involve a broad spectrum of math that ranges from arithmetic to computational modeling. The games reveal how goals and particular contextual features impact approaches to mathematical problem solving. The findings extend prior work on mathematical problem solving in physics to a new population of professional researchers, engineers, and technicians in their workplaces. The research may guide new approaches for developing problems and explicitly teaching problem solving in diverse physics contexts, which may additionally benefit undergraduate students' preparation for their future careers.

We investigated physics students' epistemological views on measurements and validity of experimental results. The roles of experiments in physics have been underemphasized in previous research on students' personal epistemology, and there is a need for a broader view of personal epistemology that incorporates experiments. An epistemological framework incorporating the structure, methodology, and validity of scientific knowledge guided the development of an open-ended survey. The survey was administered to students in algebra-based and calculus-based introductory physics courses, upper-division physics labs, and physics Ph.D. students. Within our sample, we identified several differences in students' ideas about validity and uncertainty in measurement. The majority of introductory students justified the validity of results through agreement with theory or with results from others. Alternatively, Ph.D. students frequently justified the validity of results based on the quality of the experimental process and repeatability of results. When asked about the role of uncertainty analysis, introductory students tended to focus on the representational roles (e.g., describing imperfections, data variability, and human mistakes). However, advanced students focused on the inferential roles of uncertainty analysis (e.g., quantifying reliability, making comparisons, and guiding refinements). The findings suggest that lab courses could emphasize a variety of approaches to establish validity, such as by valuing documentation of the experimental process when evaluating the quality of student work. In order to emphasize the role of uncertainty in an authentic way, labs could provide opportunities to iterate, make repeated comparisons, and make decisions based on those comparisons.

This study examines students' reasoning surrounding seemingly contradictory Likert-scale responses within five items in the Colorado Learning Attitudes About Science Survey for Experimental Physics (E-CLASS). We administered the E-CLASS with embedded open-ended prompts, which asked students to provide explanations after making a Likert-scale selection. The quantitative scores on those items showed that our sample of the 216 students enrolled in first year and beyond first year physics courses demonstrated the same trends as previous national data. A qualitative analysis of students' open-ended responses was used to examine common reasoning patterns related to particular Likert-scale responses. When explaining responses to items regarding the role of experiments in confirming known results and also contributing to the growth of scientific knowledge, a common reasoning pattern suggested that confirming known results in a classroom experiment can help with understanding concepts. Thus, physics experiments contribute to students' personal scientific knowledge growth, while also confirming widely known results. Many students agreed that having correct formatting and making well-reasoned conclusions are the main goal for communicating experimental results. Students who focused on sections and formatting emphasized how it enables clear and efficient communication. However, very few students discussed the link between well-reasoned conclusions and effective scientific communication. Lastly, many students argued it was possible to complete experiments without understanding equations and physics concepts. The most common justification was that they could simply follow instructions to finish the lab without understanding. The findings suggest several implications for teaching physics laboratory courses, for example, incorporating some lab activities with outcomes that are unknown to the students might have a significant impact on students' understanding of experiments as an important approach for developing scientific knowledge.

We review and extend existing frameworks on modeling to develop a new framework that describes model-based reasoning in introductory and upper-division physics laboratories. Constructing and using models are core scientific practices that have gained significant attention within K-12 and higher education. Although modeling is a broadly applicable process, within physics education, it has been preferentially applied to the iterative development of broadly applicable principles (e.g., Newton's laws of motion in introductory mechanics). A significant feature of the new framework is that measurement tools (in addition to the physical system being studied) are subjected to the process of modeling. Think-aloud interviews were used to refine the framework and demonstrate its utility by documenting examples of model-based reasoning in the laboratory. When applied to the think-aloud interviews, the framework captures and differentiates students' model-based reasoning and helps identify areas of future research. The interviews showed how students productively applied similar facets of modeling to the physical system and measurement tools: construction, prediction, interpretation of data, identification of model limitations, and revision. Finally, we document students' challenges in explicitly articulating assumptions when constructing models of experimental systems and further challenges in model construction due to students' insufficient prior conceptual understanding. A modeling perspective reframes many of the seemingly arbitrary technical details of measurement tools and apparatus as an opportunity for authentic and engaging scientific sense making. [This paper is part of the Focused Collection on Upper Division Physics Courses.]

Developing expertise in physics problem solving requires the ability to use mathematics effectively in physical scenarios. Novices and experts often perceive the use of mathematics in physics differently. Students' perceptions and how they frame the use of mathematics in physics play an important role in their physics problem solving. In this study, we examined students' epistemological framing about using mathematics in physics in two types of problems: a conventional problem and a hypothetical debate problem. We found that when solving a conventional physics problem, students tended to frame problem solving in physics as rote equation chasing, i.e., plugging quantities into a memorized physics equation. In hypothetical debate problems, students were more likely to be involved in quantitative or qualitative sense making. We conclude that hypothetical debate problems might be used as an instructional tool for engaging students in sense making while using mathematics in physics. Thus, it might be potentially useful for developing more expertlike problem solving expertise.

This study focuses on students' use of the mathematical concept of differentials in physics problem solving. For instance, in electrostatics, students need to set up an integral to find the electric field due to a charged bar, an activity that involves the application of mathematical differentials (e.g., "dr," "dq"). In this paper we aim to explore students' reasoning about the differential concept in physics problems. We conducted group teaching or learning interviews with 13 engineering students enrolled in a second-semester calculus-based physics course. We amalgamated two frameworks--the resources framework and the conceptual metaphor framework--to analyze students' reasoning about differential concept. Categorizing the mathematical resources involved in students' mathematical thinking in physics provides us deeper insights into how students use mathematics in physics. Identifying the conceptual metaphors in students' discourse illustrates the role of concrete experiential notions in students' construction of mathematical reasoning. These two frameworks serve different purposes, and we illustrate how they can be pieced together to provide a better understanding of students' mathematical thinking in physics. (Contains 2 tables and 3 figures.)

Through their capacity to secrete, upon activation, a variety of bioactive molecules, brain macrophages (and resident microglia) play an important role in brain immune and inflammatory responses. To test our hypothesis that activated macrophages induce neuronal injury by enhancing neuronal outward K+ current, we studied the effects of lipopolysaccharide (LPS)-stimulated human monocyte-derived macrophage (MDM) on neuronal transient A-type K+ current ( IA) and resultant neuronal injury in primary rat hippocampal neuronal cultures. Bath application of LPS-stimulated MDM-conditioned media (MCM+) enhanced neuronal IA in a concentration-dependent manner. Non-stimulated MCM (MCM-) failed to alter IA. The enhancement of neuronal IA was recapitulated in neurons co-cultured with macrophages. The link of MCM(+)-induced enhancement of IA to MCM(+)-associated neuronal injury, as detected by propidium iodide and 4″,6-diamidino-2-phenylindol staining (DAPI) and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay, was demonstrated by experimental results showing that addition of IA blocker 4-aminopyridine to the cultures protected hippocampal neurons from MCM(+)-induced neuronal injury. Further investigation revealed that glutamate was involved in MCM(+)-induced enhancement of neuronal IA. These results suggest that during brain inflammation macrophages (and microglia) might mediate neuronal injury via enhancement of neuronal IA, and that neuronal Kv channel might be a potential target for the development of therapeutic strategies for some neurodegenerative disorders by which immune and inflammatory responses are believed to be involved in the pathogenesis. [ABSTRACT FROM AUTHOR]