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1.
We have designed, developed, and validated a 17-question Meiosis Concept Inventory (Meiosis CI) to diagnose student misconceptions on meiosis, which is a fundamental concept in genetics. We targeted large introductory biology and genetics courses and used published methodology for question development, which included the validation of questions by student interviews (n = 28), in-class testing of the questions by students (n = 193), and expert (n = 8) consensus on the correct answers. Our item analysis showed that the questions’ difficulty and discrimination indices were in agreement with published recommended standards and discriminated effectively between high- and low-scoring students. We foresee other institutions using the Meiosis CI as both a diagnostic tool and an instrument to assess teaching effectiveness and student progress, and invite instructors to visit http://q4b.biology.ubc.ca for more information.  相似文献   

2.
Objective: To compare the peri-operative outcomes for laparoscopic distal pancreatectomy (LDP) and open distal pancreatectomy (ODP) for benign or premalignant pancreatic neoplasms in two institutions. Methods: This prospective comparative study included 91 consecutive patients who underwent LDP (n=45) or ODP (n=46) from Jan. 2010 to Dec. 2012. Demographics, intra-operative characteristics, and post-operative outcomes were compared. Results: The median operating time in the LDP group was (158.7±38.3) min compared with (92.2±24.1) min in the ODP group (P<0.001). Patients had lower blood loss in LDP than in the ODP (122.6±61.1) ml vs. (203.1±84.8) ml, P<0.001). The rates of splenic conservation between the LDP and ODP groups were similar (53.3% vs. 47.8%, P=0.35). All spleen-preserving distal pancreatectomies were conducted with vessel preservation. LDP also demonstrated better post-operative outcomes. The time to oral intake and normal daily activities was faster in the LDP group than in the ODP group (1.6±0.5) d vs. (3.2±0.7) d, P<0.01; (1.8±0.4) d vs. (2.1±0.6) d, P=0.02, respectively), and the postoperative length of hospital stay in LDP was shorter than that in ODP (7.9±3.8) d vs. (11.9±5.8) d, P=0.006). No difference in tumor size (4.7±3.2) cm vs. (4.5±1.8) cm, P=0.77) or overall pancreatic fistula rate (15.6% vs. 19.6%, P=0.62) was found between the groups, while the overall post-operative complication rate was lower in the LDP group (26.7% vs. 47.8%, P=0.04). Conclusions: LDP is safe and effective for benign or premalignant pancreatic neoplasms, featuring lower blood loss and substantially faster recovery.  相似文献   

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4.
Natural selection as a mechanism of evolution is a central concept in biology; yet, most nonbiology‐majors do not thoroughly understand the theory even after instruction. Many alternative conceptions on this topic have been identified, indicating that the job of the instructor is a difficult one. This article presents a new diagnostic test to assess students' understanding of natural selection. The test items are based on actual scientific studies of natural selection, whereas previous tests have employed hypothetical situations that were often misleading or oversimplified. The Conceptual Inventory of Natural Selection (CINS) is a 20‐item multiple choice test that employs common alternative conceptions as distractors. An original 12‐item version of the test was field‐tested with 170 nonmajors in 6 classes and 43 biology majors in 1 class at 3 community colleges. The test scores of one subset of nonmajors (n = 7) were compared with the students' performances in semistructured interviews. There was a positive correlation between the test scores and the interview scores. The current 20‐item version of the CINS was field‐tested with 206 students in a nonmajors' general biology course. The face validity, internal validity, reliability, and readability of the CINS are discussed. Results indicate that the CINS will be a valuable tool for instructors. © 2002 Wiley Periodicals, Inc. J Res Sci Teach 39: 952–978, 2002  相似文献   

5.
How teachers and students deal with assessment practices is largely influenced by the conceptions they hold about the purpose of assessment. This means that, given the current plea for a paradigm shift from Assessment of Learning to Assessment for Leaning with a balance between the formative and summative purposes of assessment, the study of teachers’ and students’ conceptions of the purpose of assessment is of the utmost relevance. In this study Dutch secondary school teachers’ (n = 351) and students’ (n = 712) conceptions of the purpose of assessment were measured using a translation of the teachers’ conceptions of assessment questionnaire and a translated and shortened version of the students’ conceptions of assessment questionnaire. Maximum Likelihood factor analyses resulted in four teacher and five student conceptions of the purpose of assessment. The results indicate that the teachers in our sample did not distinguish between formative and summative purposes of assessment. They did discern classroom assessment (formative as well as summative) from school accountability. In addition, they conceive assessment as being of bad (in terms of measurement errors) or good quality. In contrast with the teachers, students do make a distinction between the formative and summative purpose of assessment. They also refer to school accountability and the affects that assessment triggers in them as further purposes of assessment.  相似文献   

6.
Understanding how situational features of assessment tasks impact reasoning is important for many educational pursuits, notably the selection of curricular examples to illustrate phenomena, the design of formative and summative assessment items, and determination of whether instruction has fostered the development of abstract schemas divorced from particular instances. The goal of our study was to employ an experimental research design to quantify the degree to which situational features impact inferences about participants’ understanding of Mendelian genetics. Two participant samples from different educational levels and cultural backgrounds (high school, n = 480; university, n = 444; Germany and USA) were used to test for context effects. A multi-matrix test design was employed, and item packets differing in situational features (e.g., plant, animal, human, fictitious) were randomly distributed to participants in the two samples. Rasch analyses of participant scores from both samples produced good item fit, person reliability, and item reliability and indicated that the university sample displayed stronger performance on the items compared to the high school sample. We found, surprisingly, that in both samples, no significant differences in performance occurred among the animal, plant, and human item contexts, or between the fictitious and “real” item contexts. In the university sample, we were also able to test for differences in performance between genders, among ethnic groups, and by prior biology coursework. None of these factors had a meaningful impact upon performance or context effects. Thus some, but not all, types of genetics problem solving or item formats are impacted by situational features.  相似文献   

7.
In research on the nature of science, there is a need to investigate the role and status of different scientific knowledge forms. Theories and models are two of the most important knowledge forms within biology and are the focus of this study. During interviews, preservice biology teachers (N = 10) were asked about their understanding of theories and models. They were requested to give reasons why they see theories and models as either tentative or certain constructs. Their conceptions were then compared to philosophers’ positions (e.g., Popper, Giere). A category system was developed from the qualitative content analysis of the interviews. These categories include 16 conceptions for theories (n tentative = 11; n certain  = 5) and 18 conceptions for models (n tentative = 10; n certain = 8). The analysis of the interviews showed that the preservice teachers gave reasons for the tentativeness or certainty of theories and models either due to their understanding of the terms or due to their understanding of the generation or evaluation of theories and models. Therefore, a variety of different terminology, from different sources, should be used in learning-teaching situations. Additionally, an understanding of which processes lead to the generation, evaluation, and refinement or rejection of theories and models should be discussed with preservice teachers. Within philosophy of science, there has been a shift from theories to models. This should be transferred to educational contexts by firstly highlighting the role of models and also their connections to theories.  相似文献   

8.
A single experiment is reported in which introductory psychology students were administered a multiple-choice test on psychology with either 4 (n = 78) or 5 alternatives (n = 92) prior to any lectures being delivered. Two answers were generated for each question: a small answer consisting of their favorite alternative, and a large answer consisting of all alternatives except for their least favorite one. They also rated confidence of the accuracy of both answers and selected one for grading (plurality option). Replicating previous research, there was evidence of a confidence-accuracy (C-A) dissociation for selected answers. Specifically, accuracy was higher, but confidence was lower, for selected large answers compared to selected small answers. However, unlike previous research, the C-A dissociation was coupled with marked underconfidence for both types of selected answers. The results are discussed in terms of option fixation, the base-rate fallacy, response criteria, and alternative plausibility.  相似文献   

9.
Although we agree with Theobold and Freeman (2014) that linear models are the most appropriate way in which to analyze assessment data, we show the importance of testing for interactions between covariates and factors.To the Editor:Recently, Theobald and Freeman (2014) reviewed approaches for measuring student learning gains in science, technology, engineering, and mathematics (STEM) education research. In their article, they highlighted the shortcomings of approaches such as raw change scores, normalized gain scores, normalized change scores, and effect sizes when students are not randomly assigned to classes based on the different pedagogies that are being compared. As an alternative, they propose using linear regression models in which characteristics of students, such as pretest scores, are included as independent variables in addition to treatments. Linear models that include both continuous and categorical independent variables are often termed analysis of covariance (ANCOVA) models. The approach of using ANCOVA to control for differences in students among treatments groups has been suggested previously by Weber (2009) . We largely agree with Theobald and Freeman (2014) and Weber (2009) that ANCOVA models are an appropriate method for situations in which students cannot be randomly assigned to treatments and controls. However, in describing how to implement linear regression models to examine student learning gains, Theobald and Freeman (2014) ignore a fundamental assumption of ANCOVA.ANCOVA assumes homogeneity of slopes (McDonald, 2009 ; Sokal and Rohlf, 2011 ). In other words, the slope of the relationship between the covariate (e.g., pretest score) and the dependent variable (e.g., posttest score) is the same for the treatment group and the control. This assumption is a strict assumption of ANCOVA in that violations of this assumption can result in incorrect conclusions (Engqvist, 2005 ). For example, in Figure 1, both pretest score and treatment have statistically significant main effects in a linear model with only pretest score (F(1, 97) = 25.6, p < 0.001) and treatment (F(1, 97) = 42.6, p < 0.01) as independent variables. Therefore, we would conclude that all students in the class with pedagogical innovation had significantly greater posttest scores than those students in the control class for a given pretest score. Furthermore, we would conclude that the pedagogical innovation led to the same increase in score for all students in the treatment class, independent of their pretest scores. Clearly, neither of these conclusions would be justified.Researchers must first test the assumption of the homogeneity of slopes by including an interaction term (covariate × treatment) in their linear model (McDonald, 2009 ; Weber 2009 ; Sokal and Rohlf, 2011 ). For example, if we measured student achievement in two courses with different instructional approaches in a typical pretest/posttest design, then the interaction between students’ pretest scores and the type of instruction must be considered, because the instruction may have a different effect for high- versus low-achieving students. If multiple covariates are included in the linear model (see Equation 1 in Theobald and Freeman, 2014 ), then interaction terms need to be included for each of the covariates in the model. If the interaction term is statistically significant, this suggests that the relationship between the covariate and the dependent variable is different for each treatment group (F(1, 96) = 25.1, p < 0.001; Figure 1). As a result, the effect of the treatment will depend on the value of the covariate, and universal statements about the effect of the treatment are not appropriate (Engqvist, 2005 ). If the interaction term is not statistically significant, it should be removed from the model and the analysis rerun without the interaction term. Failure to remove an interaction term that was not statistically significant also can lead to an incorrect conclusion (Engqvist, 2005 ). Whether there are statistically significant interactions between the “treatment” and the covariates in the data set used by Theobald and Freeman (2014) is unclear.Open in a separate windowFigure 1.Simulated data to demonstrate heterogeneity of slopes. Pretest values were generated from random normal distributions with mean = 59.8 (SD = 18.1) for the treatment course and mean = 59.3 (SD = 17.0) for the control course, based on values given in Theobald and Freeman (2014) . For the treatment course, posttest values were calculated using the formula posttesti = 80 + 0.1 × pre-testi + Ɛi, where Ɛi was selected from a random normal distribution with mean = 0 (SD = 10). For the control course, posttest values were calculated using the formula posttesti = 42 + 0.5 × pre-testi + Ɛi, where Ɛi was selected from a random normal distribution with mean = 0 (SD = 10). n = 50 for both courses.In addition to being a strict assumption of ANCOVA, testing for homogeneity of slopes in a linear model is important in STEM education research, as slopes are likely heterogeneous for several reasons. First, for many instruments used in STEM education research, high-achieving students score high on the pretest. As a result, their ability to improve is limited due to the ceiling effect, and differences between treatment and control groups in posttest scores are likely to be minimal (Figure 1). In contrast, low-achieving students have a greater opportunity to change their scores between their pretest and posttest. Second, pedagogical innovations are more likely to have a greater impact on the learning of lower-performing students than higher-performing students. For example, Beck and Blumer (2012) found statistically greater gains in student confidence and scientific reasoning skills for students in the lowest quartile as compared with students in the highest quartile on pretest assessments in inquiry-based laboratory courses.Theobald and Freeman (2014, p. 47) note that “regression models can also include interaction terms that test whether the intervention has a differential impact on different types of students.” Yet, we argue that these terms must be included and only should be excluded if they are not statistically significant.  相似文献   

10.
We studied gains in student learning over eight semesters in which an introductory biology course curriculum was changed to include optional verbal final exams (VFs). Students could opt to demonstrate their mastery of course material via structured oral exams with the professor. In a quantitative assessment of cell biology content knowledge, students who passed the VF outscored their peers on the medical assessment test (MAT), an exam built with 40 Medical College Admissions Test (MCAT) questions (66.4% [n = 160] and 62% [n = 285], respectively; p < 0.001);. The higher-achieving students performed better on MCAT questions in all topic categories tested; the greatest gain occurred on the topic of cellular respiration. Because the VF focused on a conceptually parallel topic, photosynthesis, there may have been authentic knowledge transfer. In longitudinal tracking studies, passing the VF also correlated with higher performance in a range of upper-level science courses, with greatest significance in physiology, biochemistry, and organic chemistry. Participation had a wide range but not equal representation in academic standing, gender, and ethnicity. Yet students nearly unanimously (92%) valued the option. Our findings suggest oral exams at the introductory level may allow instructors to assess and aid students striving to achieve higher-level learning.  相似文献   

11.
The landscape of science education is being transformed by the new Framework for Science Education (National Research Council, A framework for K-12 science education: practices, crosscutting concepts, and core ideas. The National Academies Press, Washington, DC, 2012), which emphasizes the centrality of scientific practices—such as explanation, argumentation, and communication—in science teaching, learning, and assessment. A major challenge facing the field of science education is developing assessment tools that are capable of validly and efficiently evaluating these practices. Our study examined the efficacy of a free, open-source machine-learning tool for evaluating the quality of students’ written explanations of the causes of evolutionary change relative to three other approaches: (1) human-scored written explanations, (2) a multiple-choice test, and (3) clinical oral interviews. A large sample of undergraduates (n = 104) exposed to varying amounts of evolution content completed all three assessments: a clinical oral interview, a written open-response assessment, and a multiple-choice test. Rasch analysis was used to compute linear person measures and linear item measures on a single logit scale. We found that the multiple-choice test displayed poor person and item fit (mean square outfit >1.3), while both oral interview measures and computer-generated written response measures exhibited acceptable fit (average mean square outfit for interview: person 0.97, item 0.97; computer: person 1.03, item 1.06). Multiple-choice test measures were more weakly associated with interview measures (r = 0.35) than the computer-scored explanation measures (r = 0.63). Overall, Rasch analysis indicated that computer-scored written explanation measures (1) have the strongest correspondence to oral interview measures; (2) are capable of capturing students’ normative scientific and naive ideas as accurately as human-scored explanations, and (3) more validly detect understanding than the multiple-choice assessment. These findings demonstrate the great potential of machine-learning tools for assessing key scientific practices highlighted in the new Framework for Science Education.  相似文献   

12.
Genetics instruction in introductory biology is often confined to Mendelian genetics and avoids the complexities of variation in quantitative traits. Given the driving question “What determines variation in phenotype (Pv)? (Pv=Genotypic variation Gv + environmental variation Ev),” we developed a 4-wk unit for an inquiry-based laboratory course focused on the inheritance and expression of a quantitative trait in varying environments. We utilized Brassica rapa Fast Plants as a model organism to study variation in the phenotype anthocyanin pigment intensity. As an initial curriculum assessment, we used free word association to examine students’ cognitive structures before and after the unit and explanations in students’ final research posters with particular focus on variation (Pv = Gv + Ev). Comparison of pre- and postunit word frequency revealed a shift in words and a pattern of co-occurring concepts indicative of change in cognitive structure, with particular focus on “variation” as a proposed threshold concept and primary goal for students’ explanations. Given review of 53 posters, we found ∼50% of students capable of intermediate to high-level explanations combining both Gv and Ev influence on expression of anthocyanin intensity (Pv). While far from “plug and play,” this conceptually rich, inquiry-based unit holds promise for effective integration of quantitative and Mendelian genetics.  相似文献   

13.
Objective: The intoxications caused by 2,4-dinitrophenol (2,4-DNP), even death, have been frequently reported in recent years. This study aims to investigate the dynamic changes of plasma toxin concentration and explore the clinical value of resin hemoperfusion (HP) in the treatment of patients with acute 2,4-DNP poisoning. Methods: We reported 16 cases of acute 2,4-DNP poisoning through occupational exposure due to ignoring the risk of poisoning. The blood samples were collected from the 14 survivors. According to the different treatments of resin HP, the survivors were divided into routine HP (n=5) and intensive HP (n=9) groups. Ultra high performance liquid chromatography/tandem mass spectroscopy (UPLC-MS/MS) was used to detect the 2,4-DNP concentration in plasma in this study. Results: The 14 survivors recovered very well after treatment. The initial plasma 2,4-DNP concentrations (C 1) of survivors ranged from 0.25 to 41.88 µg/ml (mean (12.56±13.93) µg/ml). A positive correlation existed between initial plasma 2,4-DNP concentration (C 1) and temperature. The elimination of 2,4-DNP was slow and persistent, and the total clearance rates of plasma toxin from the 1st to 3rd day (R 3), the 3rd to 7th day (R 3–7), and the 1st to 7th day (R 7), were only (53.03±14.04)%, (55.25±10.50)%, and (78.29±10.22)%, respectively. The plasma toxin was cleared up to 25 d after poisoning in most of the patients. The R 3, R 3–7, and R 7 in the intensive HP group were all apparently higher than those in the routine HP group, with statistical significance (P<0.05). Simultaneously, the elimination half-life (t 1/2) of 2,4-DNP in the intensive HP group was apparently shorter than that in the routine HP group, with statistical significance (P<0.05). Conclusions: The clinicians should be aware of this slow and persistent process in the elimination of plasma 2,4-DNP. Higher initial plasma toxin concentration resulted in a more severe fever for the patient. According to the limited data, longer and more frequent resin HP may accelerate to eliminate the poison.  相似文献   

14.
The distinct learning behaviors observed in the classroom between American and Chinese students have been discussed extensively in literature. The authors speculated that learning approaches (structure-oriented approach vs. depth-oriented approach) might play a role in explaining different behavioral traits presented by American and Chinese students. Two measures assessing learning approaches and learning behaviors in the classroom were administered to two samples: American undergraduates (n = 199) and Chinese undergraduates (n = 265). The results revealed that American undergraduates appeared to be more “active” in the classroom compared to Chinese undergraduates. Chinese undergraduates scored significantly higher on the structure-oriented approach, but did not differ significantly in the depth-oriented approach compared to American undergraduates. The results also indicated that the structure-oriented approach mediated the relationship between cultural group and learning behavior, and thus suggest that the structure-oriented learning approach might partially explain the distinct behavioral traits presented by American and Chinese students in the classroom.  相似文献   

15.
The American Association for the Advancement of Science 2011 report Vision and Change in Undergraduate Biology Education encourages the teaching of developmental biology as an important part of teaching evolution. Recently, however, we found that biology majors often lack the developmental knowledge needed to understand evolutionary developmental biology, or “evo-devo.” To assist in efforts to improve evo-devo instruction among undergraduate biology majors, we designed a concept inventory (CI) for evolutionary developmental biology, the EvoDevoCI. The CI measures student understanding of six core evo-devo concepts using four scenarios and 11 multiple-choice items, all inspired by authentic scientific examples. Distracters were designed to represent the common conceptual difficulties students have with each evo-devo concept. The tool was validated by experts and administered at four institutions to 1191 students during preliminary (n = 652) and final (n = 539) field trials. We used student responses to evaluate the readability, difficulty, discriminability, validity, and reliability of the EvoDevoCI, which included items ranging in difficulty from 0.22–0.55 and in discriminability from 0.19–0.38. Such measures suggest the EvoDevoCI is an effective tool for assessing student understanding of evo-devo concepts and the prevalence of associated common conceptual difficulties among both novice and advanced undergraduate biology majors.  相似文献   

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17.
At the close of the Society for the Advancement of Biology Education Research conference in July 2012, one of the organizers made the comment: “Misconceptions are so yesterday.” Within the community of learning sciences, misconceptions are yesterday''s news, because the term has been aligned with eradication and/or replacement of conceptions, and our knowledge about how people learn has progressed past this idea. This essay provides an overview of the discussion within the learning sciences community surrounding the term “misconceptions” and how the education community''s thinking has evolved with respect to students’ conceptions. Using examples of students’ incorrect ideas about evolution and ecology, we show that students’ naïve ideas can provide the resources from which to build scientific understanding. We conclude by advocating that biology education researchers use one or more appropriate alternatives in place of the term misconception whenever possible.  相似文献   

18.
The 1st step in successfully intervening with students who may fail a course is to identify them as early as possible in the semester. The objective of this study was to create a model to predict student performance in FDSC 4304, the required capstone Food Chemistry class, using academic performance in prerequisite courses as potential predictors. We analyzed data for 116 undergraduates who completed Food Chemistry (FDSC 4304) between 2008 and 2015. Data included semester of enrollment and grade earned in FDSC 4304; transfer status; grades in prerequisite classes in science, math, and statistics courses and an introductory Food Science course, FDSC 1103; and the students’ university GPA at the time of enrollment in FDSC 4304. Cumulative GPA had the strongest significant (P < 0.001) positive correlation with FDSC 4304 grade (r = 0.64), followed by grade in statistics GPA (r = 0.52), FDSC 1103 grade (r = 0.45), pre‐requisite chemistry GPA (r = 0.44), and biology GPA (r = 0.42). When using partial correlations to control for cumulative GPA, only grades in FDSC 1103 (completed by 62.9% of students) were significantly correlated with grades in FDSC 4304. Linear regression indicated cumulative GPA and FDSC 1103 grades explained 35.5% of the variance in FDSC 4304 grades. When cumulative GPA (available for 91.6% of students) alone was regressed on FDSC 4304, it explained 40.6% of the variance for the larger group. Lower cumulative GPAs and FDSC 1103 grades are suggestive but not determinative of potential student struggles in FDSC 4304. Instructors should use cumulative GPAs and introductory food science course grades (either alone or in combination) with actual early course performance measures to identify students in need of additional help.  相似文献   

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20.
Genetics Reasoning with Multiple External Representations   总被引：1，自引：0，他引：1  
This paper explores a case study of a class of Year 10 students (n=24) whose learning of genetics involved activities of BioLogica, a computer program that features multiple external representations (MERs). MERs can be verbal/textual, visual-graphical, or in other formats. Researchers claim that the functions of MERs in supporting student learning are to complement information or processes, to constrain the interpretation of abstract concepts, and to construct new viable conceptions. Over decades, research has shown that genetics remains linguistically and conceptually difficult for high school students. This case study using data from multiple sources enabled students' development of genetics reasoning to be interpreted from an epistemological perspective. Pretest-posttest comparison after six weeks showed that most of the students (n=20) had improved their genetics reasoning but only for easier reasoning types. Findings indicated that the MERs in BioLogica contributed to students' development of genetics reasoning by engendering their motivation and interest but only when students were mindful in their learning. Based on triangulation of data from multiple sources, MERs in BioLogica appeared to support learning largely by constraining students' interpretation of phenomena of genetics.  相似文献   

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