Processes of problem-solving and instructional change in physics

Doctor of PhilosophyDepartment of PhysicsEleanor C. SayreThis research presents an investigation of how students solve physics problems and how physics instructors approach changes in their teaching. In particular, the first part of this dissertation focuses on three major projects looking at students' processes of problem-solving in upper-division physics courses. The second part focuses on the processes of instructional change. In the first project described in part I, I discuss the clusters of resources that emerge when upper-division students write about electromagnetic fields in linear materials. I use a resource theory perspective to describe the ways students link pieces of information (or resources) to form more complex ideas, improve their understanding, and solve physics problems. The evidence shows that students benefit from activating resources related to the internal structure of the atom when thinking about electric fields to complete their mental model. Physics as a discipline embeds conceptual meaning about the physical world in mathematical formalism. In the second project, I use Sherin's symbolic forms theory to present an analysis of the different physical meanings associated with the equal signs across a physics context. Sherin's symbolic forms framework links mathematical equations to intuitive conceptual ideas. I delineate types of equal signs as used in five undergraduate level physics textbooks and develop a categorization scheme. Six distinct meanings are identified: causality, balancing, definitional, assignment, hybrid, and calculation. After considering five physics textbooks, I then analyze students' solutions in their written homework in an upper-division electrostatics course and compare them to textbook solutions. In doing so, I am able to look for patterns and compare the ways students use the equal signs to the textbook solution manual. In the last section of Part I, I examine students' epistemological framing when solving physics problems as a group. I analyze videos of students solving electrodynamics problems. I consider two epistemic frames which are common in students' discussions during problem solving in group: sense-making and answer-making. I first characterize the markers of each frame, focusing on analyzing students' group frame. Then, I present a pair of examples that show how often students transition between these frames. I notice moments that students change their attitude towards the problem to move forward in their activities. While there are many ways to view how students practice physics, the results of this project provide deeper insight into students' problem-solving processes in an upper-division course. In Part II, I use phenomenography as a methodology to explain how physics instructors approach making changes in their teaching and the different kinds of support that they would like to have. The purpose of phenomenography is to describe the qualitative variation in people's experiences. For example, what are the ways in which physics instructors think and talk about their teaching practices? Our phenomenography study explored six different major categories: how instructors approach their teaching, their motivation to make changes, resources that they have used, how they have implemented those resources, challenges they experience during a semester, and their attitudes towards implementing new changes. We ultimately aim to use our findings to redesign the PhysPort website

The effect of Ginger (Zingiber officinale) on electrophoretic pattern of serum proteins of male mice

چکیده: زمینه و هدف: زمینه و هدف: زنجبیل (Zingiber officinale) به عنوان ادویه در رژیم غذایی بسیاری از مناطق دنیا استفاده می شود. تحقیقات اخیر نشان داده است که زنجبیل بسته به ترکیبات فعال مختلف (شامل شوگاال ها و جینجرول ها)، اثرات دارویی مختلفی دارد. هدف این مطالعه تعیین اثر عصاره الکلی زنجبیل بر روی الگوی الکتروفورتیک اجزای پروتئینی سرم در موش های کوچک آزمایشگاهی بوده است. روش بررسی: در این مطالعه تجربی چهار گروه موش کوچک آزمایشگاهی نر بالغ (8 موش در هر گروه) برای آزمایش استفاده شد. گروه یک (گروه کنترل) نرمال سالین و سه گروه دیگر سه دوز متفاوت mg/kg 10 (گروه 2)، mg/kg 20 (گروه 3) و mg/kg 40 (گروه 4) عصاره الکلی زنجبیل را هر 4 ساعت به مدت بیست روز از طریق تزریق داخل صفاقی دریافت نمودند. سپس خون گیری از طریق سینوس چشمی انجام و سطوح پروتئینی پره آلبومین، آلفا-1، آلفا-2، بتا و گاما گلبولین ها با روش الکتروفورز جدا و به کمک برنامه ویژه کامپیوتری تفکیک پروتئین های سرم اندازه گیری شد. نسبت A/G (نسبت آلبومین به گلبولین) با استفاده از الگوی الکتروفورتوگرام محاسبه گردید. داده ها با استفاده از آزمون توکی و آزمون تعقیبی تجزیه و تحلیل شدند. یافته ها: عصاره الکلی زنجبیل به طور معنی داری سطوح آلبومین و پروتئین تام سرم را در گروه سوم (g/dl 25/0±7/3) و چهارم (g/dl 37/0±71/3) در مقایسه با گروه کنترل افزایش داد (05/0P). نسبت A/G به طور معنی داری در گروه سه (g/dl 48/0±05/2) بیشتر از گروه کنترل (g/dl 16/0±37/1) بود (05/0

Analyzing Physics Majors' Specialization Low Interest Using Social Cognitive Career Theory

As students pursue a bachelor's degree in physics, they may ponder over which area to specialize in, such as theory, computation, or experiment. Often students develop preferences and dislikes, but it's unclear when this preference solidifies during their undergraduate experiences. To get a better understanding, we interviewed eighteen physics majors who were at different stages of their degree regarding their interest in theory, computation, and experimental methods. Out of the eighteen students, we chose to analyze only nine students who rated computation and theory the lowest. Our analysis did not include interest in experiment because the ratings were less negative. We used Social Cognitive Career Theory (SCCT) and Lucidchart to analyze students' responses and create individual graphical representations of the influences for each student. Through this, we uncovered how various factors such as learning experiences, self-efficacy, and outcome expectations influenced their low interest in a particular method. We found that lack of knowledge and experience is often the main reason why self-efficacy was lower. Students' lack of interest is also influenced by negative outcome expectations (e.g, math-intensive and a bad work-life balance) more than other SCCT factors. Our findings could help physics departments and educators identify positive and negative factors that could lead to a more motivating and inclusive physics curriculum.Comment: 4 pages, 2 figures, submitted to the Physics Education Research Conference 202

Evaluation of post-acrosomal sheath WW domain binding protein expression in spermatozoa from infertile men with varicocele

Background: Post-acrosomal sheath WW domain binding protein (PAWP) is one of sperm factors related to oocyte activation and is expressed in elongating spermatid. Previously, the effect of high of testicular temperature in infertile men with varicocele on semen quality, sperm DNA damage, expression of genes and proteins were reported. In this study, expression of PAWP at RNA and protein levels, and also sperm DNA damage were compared between fertile and infertile men with varicocele. Methods: In this case-control study, semen samples were collected from 35 infertile men with varicocele (grade II & III) and 20 fertile men referring to Isfahan Fertility and Infertility Center from January 2016 to September 2016. Ejaculated semen was obtained by masturbation into a sterile plastic container after 3-5 days of abstinence and was allowed to liquefy at room temperature. Briefly, sperm concentration, motility and morphology were evaluated using a sperm chamber (Sperm meter; Sperm Processor, Aurangabad, India), Computer Assisted Semen Analysis (CASA, Video Test, ltd: version Sperm 2.1, Russia) and Papanicolaou staining, respectively. In addition, DNA fragmentation, expression of PAWP at RNA and protein levels were assessed by real-time PCR, and Western blot technique, respectively. Microsoft Excel 2013 (Microsoft Corp., Redmond, WA, USA) and Package for the Social Studies were used to analyze data. We used independent-samples t-test to compare the mean value between different groups. Differences with values of P<0.05 were considered as statistically significant. Results: Mean of semen volume, sperm concentration, percentage of sperm motility, and expression of PAWP at both RNA (P=0.0001) and protein (P=0.03) levels were significantly lower in infertile men with varicocele in comparison with fertile men. In addition, mean percentage of sperm abnormal morphology and sperm DNA fragmentation were significantly higher in infertile men with varicocele in comparison with fertile men (P<0.05). Conclusion: Expression of PAWP as a protein involved in spermatogenesis and fertilization process, has decreased in infertile men with varicocele. In addition, sperm DNA integrity was disrupted in these individuals that can be considered as a main etiology of infertility