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1.
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   

2.
A large-sample procedure for examining explained population variance in principal component analysis is discussed. The method yields interval estimates for the proportions of variance accounted for by the considered for retention principal components. The obtained confidence intervals can be used to make decisions about the number of selected components, based on their performance in studied populations. The approach can also be employed for ascertaining group similarity or differences in percentage explained variance by the considered principal components. The procedure is illustrated with 2 examples.  相似文献   

3.
In-depth interviews were conducted with 16 men who had a significant other who had given birth within the last 5 years. Men were asked about their perceptions of pregnancy-related weight gain, and content analysis was used to identify themes from the interviews. Men described nine themes related to perinatal weight gain: (a) negative perceptions, (b) eating behaviors, (c) exercise habits, (d) health impact, (e) body changes, (f) weight-loss success, (g) “it bothered her more than me,” (h) “the weight gain wasn’t a problem,” and (i) intimacy. Together, these themes offer a glimpse into men’s experiences and highlight the discord and balance between experiencing negative feelings/perceptions and being a supportive partner. This information on how men perceive pregnancy-related weight gain can be used to develop interventions to assist men to support their significant others in meeting weight loss goals following pregnancy.  相似文献   

4.
研究了多个相互独立的二元正态分布相关系数的相等性检验问题。定义了一个新的广义检验变量,给出了检验问题的广义p值。这种方法不依赖于大样本近似,而且可以算出广义上的精确p值,弥补了传统方法不适用于小样本的缺陷。  相似文献   

5.
In January 2010, Women’s Health Issues published two direction-setting reports from the Transforming Maternity Care (TMC) Project: “2020 Vision for a High-Quality, High-Value Maternity Care System” and “Blueprint for Action: Steps Toward a High-Quality, High-Value Maternity Care System.” This guest editorial summarizes highlights of the implementation phase of what is now known as the TMC Partnership. Major progress has been made in elevating maternity care quality to a national policy priority, increasing the availability and use of maternity care performance measures, and developing shared decision making tools for childbearing women.  相似文献   

6.
This “Celebrate Birth!” column describes the experience of a long-time childbirth educator who attended the birth of her granddaughter Cora, her daughter Robyn’s second hospital birth. She discusses how Robyn’s instincts and confidence helped to overcome institutional issues to provide a good and safe birthing experience.  相似文献   

7.
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   

8.
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9.
This feature is designed to point CBE—Life Sciences Education readers to current articles of interest in life sciences education as well as more general and noteworthy publications in education research.This feature is designed to point CBE—Life Sciences Education readers to current articles of interest in life sciences education as well as more general and noteworthy publications in education research. URLs are provided for the abstracts or full text of articles. For articles listed as “Abstract available,” full text may be accessible at the indicated URL for readers whose institutions subscribe to the corresponding journal.1. Bush SD, Pelaez NJ, Rudd JA, Stevens MT, Tanner KD, Williams KS (2013). Widespread distribution and unexpected variation among science faculty with education specialties (SFES) across the United States. Proc Natl Acad Sci USA 110, 7170–7175.[Available at: www.pnas.org/content/110/18/7170.full.pdf+html?sid=f2823860-1fef-422c-b861-adfe8d82cef5]College and university basic science departments are taking an increasingly active role in innovating and improving science education and are hiring science faculty with education specialties (SFES) to reflect this emphasis. This paper describes a nationwide survey of these faculty at private and public degree-granting institutions. The authors assert that this is the first such analysis undertaken, despite the apparent importance of SFES at many, if not most, higher education institutions. It expands on earlier work summarizing survey results from SFES used in the California state university system (Bush et al., 2011 ).The methods incorporated a nationwide outreach that invited self-identified SFES to complete an anonymous, online survey. SFES are described as those “specifically hired in science departments to specialize in science education beyond typical faculty teaching duties” or “who have transitioned after their initial hire to a role as a faculty member focused on issues in science education beyond typical faculty teaching duties.” Two hundred eighty-nine individuals representing all major types of institutions of higher education completed the 95-question, face-validated instrument. Slightly more than half were female (52.9%), and 95.5% were white. There is extensive supporting information, including the survey instrument, appended to the article.Key findings are multiple. First, but not surprisingly, SFES are a national, widespread, and growing phenomenon. About half were hired since the year 2000 (the survey was completed in 2011). Interestingly, although 72.7% were in tenured or tenure-track positions, most did not have tenure before adopting SFES roles, suggesting that such roles are not, by themselves, an impediment to achieving tenure. A second key finding was that SFES differed significantly more between institutional types than between science disciplines. For example, SFES respondents at PhD-granting institutions were less likely to occupy tenure-track positions than those at MS-granting institutions and primarily undergraduate institutions (PUIs). Also, SFES at PhD institutions reported spending more time on teaching and less on research than their non-SFES peers. This may be influenced, of course, by the probability that fewer faculty at MS and PUI institutions have research as a core responsibility. The pattern is complex, however, because all SFES at all types of institutions listed teaching, service, and research as professional activities. SFES did report that they were much more heavily engaged in service activities than their non-SFES peers across all three types of institutions. A significantly higher proportion of SFES respondents at MS-granting institutions had formal science education training (60.9%), as compared with those at PhD-granting institutions (39.3%) or PUIs (34.8%).A third finding dealt with success of SFES in obtaining funding for science education research, with funding success defined as cumulatively obtaining $100,000 or more in their current positions. Interestingly, the factors that most strongly correlated statistically with funding success were 1) occupying a tenure-track position, 2) employment at a PhD-granting institution, and 3) having also obtained funding for basic science research. Not correlated were disciplinary field and, surprisingly, formal science education training.Noting that MS-granting institutions show the highest proportions of SFES who are tenured or tenure-track, who are higher ranked, who are trained in science education, and who have professional expectations aligned with those of their non-SFES peers, the authors suggest that these institutions are in the vanguard of developing science education as an independent discipline, similar to ecology or organic chemistry. They also point out that SFES at PhD institutions appear to be a different subset, occupying primarily non–tenure track, teaching positions. To the extent that more science education research funding is being awarded to these latter SFES, who occupy less enfranchised roles within their departments, the authors suggest the possibility that such funding may not substantially improve science education at these institutions. However, the authors make it clear that the implications of their findings merit more careful examination and discussion.2. Opfer JE, Nehm RH, Ha M (2012). Cognitive foundations for science assessment design: knowing what students know about evolution. J Res Sci Teach 49, 744–777.[Abstract available: http://onlinelibrary.wiley.com/doi/10.1002/tea.21028/abstract]The authors previously published an article (Nehm et al., 2012) documenting a new instrument (more specifically, a short-answer diagnostic test), Assessing Contextual Reasoning about Natural Selection (ACORNS). This article describes how cognitive principles were used in designing the theoretical framework of ACORNS. In particular, the authors attempted to follow up on the premise of a National Research Council (2001) report on educational assessment that use of research-based, cognitive models for student learning could improve the design of items used to measure students’ conceptual understandings.In applying this recommendation to design of the ACORNS, the authors were guided by four principles for assessing the progression from novice to expert in using core concepts of natural selection to explain and discuss the process of evolutionary change. The items in ACORNS are designed to assess whether, in moving toward expertise, individuals 1) use core concepts for facilitation of long-term recall; 2) continue to hold naïve ideas coexistent with more scientifically normative ones; 3) offer explanations centered around mechanistic rather than teleological causes; and 4) can use generalizations (abstract knowledge) to guide reasoning, rather than focusing on specifics or less-relevant surface features. Thus, these items prioritize recall over recognition, detect students’ use of causal features of natural selection, test for coexistence of normative and naïve conceptions, and assess students’ focus on surface features when offering explanations.The paper provides an illustrative set of four sample items, each of which describes an evolutionary change scenario with different surface features (familiar vs. unfamiliar taxa; plants vs. animals) and then prompts respondents to write explanations for how the change occurred. To evaluate the ability of items to detect gradations in expertise, the authors enlisted the participation of 320 students enrolled in an introductory biology sequence. Students’ written explanations for each of the four items were independently coded by two expert scorers for presence of core concepts and cognitive biases (deviations from scientifically normative ideas and causal reasoning). Indices were calculated to determine the frequency, diversity, and coherence of students’ concept usage. The authors also compared the students’ grades in a subsequent evolutionary biology course to determine whether the use of core concepts and cognitive biases in their ACORNS explanations could successfully predict future performance.Evidence from these qualitative and quantitative data analyses argued that the items were consistent with the cognitive model and four guiding principles used in their design, and that the assessment could successfully predict students’ level of academic achievement in subsequent study of evolutionary biology. The authors conclude by offering examples of student explanations to highlight the utility of this cognitive model for designing assessment items that document students’ progress toward expertise.3. Sampson V, Enderle P, Grooms J (2013). Development and initial validation of the Beliefs about Reformed Science Teaching and Learning (BARSTL) questionnaire. School Sci Math 113, 3–15.[Available: http://onlinelibrary.wiley.com/doi/10.1111/j.1949-8594.2013.00175.x/full]The authors report on the development of a Beliefs about Reformed Science Teaching and Learning (BARSTL) instrument (questionnaire), designed to map teachers’ beliefs along a continuum from traditional to reform-minded. The authors define reformed views of science teaching and learning as being those that are consistent with constructivist philosophies. That is, as quoted from Driver et al. (1994 , p. 5), views that stem from the basic assumption that “knowledge is not transmitted directly from one knower to another, but is actively built up by the learner” by adjusting current understandings (and associated rules and mental models) to accommodate and make sense of new information and experiences.The basic premise for the instrument development posed by the authors is that teachers’ beliefs about the nature of science and of the teaching and learning of science serve as a filter for, and thus strongly influence how they enact, reform-based curricula in their classrooms. They cite a study from a high school physics setting (Feldman, 2002 ) to illustrate the impact that teachers’ differing beliefs can have on the ways in which they incorporate the same reform-based curriculum into their courses. They contend that, because educational reform efforts “privilege” constructivist views of teaching and learning, the BARSTL instrument could inform design of teacher education and professional development by monitoring the extent to which the experiences they offer are effective in shifting teachers’ beliefs toward the more constructivist end of the continuum.The BARTSL questionnaire described in the article has four subscales, with eight items per subscale. The four subscales are: a) how people learn about science; b) lesson design and implementation; c) characteristics of teachers and the learning environment; and d) the nature of the science curriculum. In each subscale, four of the items were designed to be aligned with reformed perspectives on science teaching and learning, and four to have a traditional perspective. Respondents indicate the extent to which they agree with the item statements on a 4-point Likert scale. In scoring the responses, strong agreement with a reform-based item is assigned a score of 4 and strong disagreement a score of 1; scores for traditional items were assigned on a reverse scale (e.g., 1 for strong agreement). A more extensive characterization of the subscales is provided in the article, along with all of the instrument items (see Appendix).The article describes the seven-step process and associated analyses used to, in the words of the authors, “assess the degree to which the BARTSL instrument has accurately translated the construct, reformed beliefs about science teaching, into an operationalization.” The steps include: 1) defining the specific constructs (concepts that can be used to explain related phenomena) that the instrument would measure; 2) developing instrument items; 3) evaluating items for clarity and comprehensibility; 4) evaluating construct and content validity of the items and subscales; 5) a first round of evaluation of the instrument; 6) item and instrument revision; and 7) a second evaluation of validity and reliability (the extent to which the instrument yields the same results on repetition). Step 3 was accomplished by science education doctoral students who reviewed the items and provided feedback, and step 4 with assistance from a seven-person panel composed of science education faculty and doctoral students. Administration of the instrument to 104 elementary teacher education majors (ETEs) enrolled in a teaching method course was used to evaluate the first draft of the instrument and identify items for inclusion in the final instrument. The instrument was administered to a separate population of 146 ETEs in step 7.The authors used two estimates of internal consistency, a Spearman-Brown corrected correlation and coefficient alpha, to assess the reliability of the instrument; the resulting values were 0.80 and 0.77, respectively, interpreted as being indicative of satisfactory internal consistency. Content validity, defined by the authors as the degree to which the sample of items measures what the instrument was designed to measure, was assessed by a panel of experts who reviewed the items within each of the four subscales. The experts concluded that items that were designed to be consistent with reformed and traditional perspectives were in fact consistent and were evenly distributed throughout the instrument. To evaluate construct validity (which was defined as the instrument''s “theoretical integrity”), the authors performed a correlation analysis on the four subscales to examine the extent to which each could predict the final overall score on the instrument and thus be viewed as a single construct of reformed beliefs. They found that each of the subscales was a good predictor of overall score. Finally, they performed an exploratory factor analysis and additional follow-up analyses to determine whether the four subscales measure four dimensions of reformed beliefs and to ensure that items were appropriately distributed among the subscales. In general, the authors contend that the results of these analyses indicated good content and construct validity.The authors conclude by pointing out that BARTSL scores could be used for quantitative comparisons of teachers’ beliefs and stances about reform-minded science teaching and learning and for following changes over time. However, they recommend BARTSL scores not be used to infer a given level of reform-mindedness and are best used in combination with other data-collection techniques, such as observations and interviews.4. Meredith DC, Bolker JA (2012). Rounding off the cow: challenges and successes in an interdisciplinary physics course for life sciences students. Am J Phys 80, 913–922.[Abstract available at: http://ajp.aapt.org/resource/1/ajpias/v80/i10/p913_s1?isAuthorized=no]There is a well-recognized need to rethink and reform the way physics is taught to students in the life sciences, to evaluate those efforts, and to communicate the results to the education community. This paper describes a multiyear effort at the University of New Hampshire by faculties in physics and biological sciences to transform an introductory physics course populated mainly by biology students into an explicitly interdisciplinary course designed to meet students’ needs.The context was that of a large-enrollment (250–320 students), two-semester Introductory Physics for Life Science Students (IPLS) course; students attend one of two lecture sections that meet three times per week and one laboratory session per week. The IPLS course was developed and cotaught by the authors, with a goal of having “students understand how and why physics is important to biology at levels from ecology and evolution through organismal form and function, to instrumentation.” The selection of topics was drastically modified from that of a traditional physics course, with some time-honored topics omitted or de-emphasized (e.g., projectile motion, relativity), and others thought to be more relevant to biology introduced or emphasized (e.g., fluids, dynamics). In addition, several themes not always emphasized in a traditional physics course but important in understanding life processes were woven through the IPLS course: scaling, estimation, and gradient-driven flows.It is well recognized that life sciences students need to strengthen their quantitative reasoning skills. To address their students’ needs in this area, the instructors ensured that online tutorials were available to students, mathematical proofs that the students are not expected use were de-emphasized, and Modeling Instruction labs were incorporated that require students to model their own data with an equation and compose a verbal link between their equations and the physical world.Student learning outcomes were assessed through the use of the Colorado Learning Attitudes about Science Survey (CLASS), which measures students’ personal epistemologies of science by their responses on a Likert-scale survey. These data were supplemented by locally developed, open-ended surveys and Likert-scale surveys to gauge students’ appreciation for the role of physics in biology. Students’ conceptual understanding was evaluated using the Force and Motion Concept Evaluation (FCME) and Test of Understanding Graphs in Kinematics (TUG-K), as well as locally developed, open-ended physics problems that probed students’ understanding in the context of biology-relevant applications and whether their understanding of physics was evident in their use of mathematics.The results broadly supported the efficacy of the authors’ approaches in many respects. More than 80% of the students very strongly or strongly agreed with the statement “I found the biological applications interesting,” and almost 60% of the students very strongly or strongly agreed with the statements “I found the biological applications relevant to my other courses and/or my planned career” and “I found the biological applications helped me understand the physics.” Students were also broadly able to integrate physics into their understanding of living systems. Examples of questions that students addressed include one that asked students to evaluate the forces on animals living in water versus those on land. Ninety-one percent of the students were able to describe at least one key difference between motion in air and water. Gains in the TUG-K score averaged 33.5% across the 4 yr of the course offering and were consistent across items. However, the positive attitudes about biology applications in physics were not associated with gains in areas of conceptual understanding measured by the FCME instrument. These gains were more mixed than those from the TUG-K and dependent on the concept being evaluated, with values as low as 15% for some concepts and an average gain on all items of 24%. Overall, the gains on the two instruments designed to measure physics understanding were described by the authors as being “modest at best,” particularly in the case of the FCME, given that reported national averages for reformed courses for this instrument range from 33 to 93%.The authors summarize by identifying considerations they think are essential to design and implementation of a IPLS-like course: 1) the need to streamline the coverage of course topics to emphasize those that are truly aligned with the needs of life sciences majors; 2) the importance of drawing from the research literature for evidence-based strategies to motivate students and aid in their development of problem-solving skills; 3) taking the time to foster collaborations with biologists who will reinforce the physics principles in their teaching of biology courses; and 4) considering the potential constraints and limitations to teaching across disciplinary boundaries and beginning to strategize ways around them and build models for sustainability. The irony of this last recommendation is that the authors report having suspended the teaching of IPLS at their institution due to resource constraints. They recommend that institutions claiming to value interdisciplinary collaboration need to find innovative ways to reward and acknowledge such collaborations, because “external calls for change resonate with our own conviction that we can do better than the traditional introductory course to help life science students learn and appreciate physics.”I invite readers to suggest current themes or articles of interest in life science education, as well as influential papers published in the more distant past or in the broader field of education research, to be featured in Current Insights. Please send any suggestions to Deborah Allen (ude.ledu@nellaed).  相似文献   

10.
Many behaviors and substances have been purported to induce labor. Using data from the Third Pregnancy, Infection, and Nutrition cohort, we focus on 663 women who experienced spontaneous labor. Of the women who reported a specific labor trigger, 32% reported physical activity (usually walking), 24% a clinician-mediated trigger, 19% a natural phenomenon, 14% some other physical trigger (including sexual activity), 12% reported ingesting something, 12% an emotional trigger, and 7% maternal illness. With the exceptions of walking and sexual intercourse, few women reported any one specific trigger, although various foods/substances were listed in the “ingesting something” category. Discussion of potential risks associated with “old wives’ tale” ways to induce labor may be warranted as women approach term.  相似文献   

11.
Our study explored the prospects and limitations of using machine-learning software to score introductory biology students’ written explanations of evolutionary change. We investigated three research questions: 1) Do scoring models built using student responses at one university function effectively at another university? 2) How many human-scored student responses are needed to build scoring models suitable for cross-institutional application? 3) What factors limit computer-scoring efficacy, and how can these factors be mitigated? To answer these questions, two biology experts scored a corpus of 2556 short-answer explanations (from biology majors and nonmajors) at two universities for the presence or absence of five key concepts of evolution. Human- and computer-generated scores were compared using kappa agreement statistics. We found that machine-learning software was capable in most cases of accurately evaluating the degree of scientific sophistication in undergraduate majors’ and nonmajors’ written explanations of evolutionary change. In cases in which the software did not perform at the benchmark of “near-perfect” agreement (kappa > 0.80), we located the causes of poor performance and identified a series of strategies for their mitigation. Machine-learning software holds promise as an assessment tool for use in undergraduate biology education, but like most assessment tools, it is also characterized by limitations.  相似文献   

12.
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13.
A standard genetic/bioinformatic activity in the genomics era is the identification within DNA sequences of an "open reading frame" (ORF) that encodes a polypeptide sequence. As an educational introduction to such a search, we provide a webapp that composes, displays for solution, and then solves short DNA exemplars with a single ORFTo the Editor: We wish to bring a new Web resource to the attention of CBE—Life Sciences Education readers.When being introduced to the central dogma of nucleic acid transactions, students are often required to identify the 5′→3′ DNA template strand in a double-stranded DNA (dsDNA) molecule; transcribe an antiparallel, complementary 5′→3′ mRNA; and then translate the mRNA codons 5′→3′ into an amino acid polypeptide by means of the genetic code table. Although this algorithm replicates the molecular genetic process of protein synthesis, experience shows that the series of left/right, antiparallel, and/or 5′→3′ reversals is confusing to many students when worked by hand. Students may also obtain the “right” answer for the “wrong” reasons, as when the “wrong” DNA strand is transcribed in the “wrong” 3′→5′ direction, so as to produce a string of letters that “translates correctly.”In genetics and bioinformatics education, we have found it more intuitively appealing to demonstrate and emphasize the equivalence of the mRNA to the DNA sense strand complement of the template strand. The sense strand is oriented in the same 5′→3′ direction and has a sequence identical to the mRNA, except for substitution of thymidine in the DNA for uracil in the mRNA. It is thus more computationally efficient to “read” the polypeptide sequence directly from this strand, with mental substitution of thymidine in the triplets of the genetic code table. (By definition, “codons” occur only in mRNA: the equivalent three-letter words in the DNA sense strand may be designated “triplets.”) This is the same logic used in DNA “translation” software programs.A further constraint often imposed on dsDNA teaching exemplars is that five of the six possible reading frames are “closed” by the occurrence of one or more “stop” triplets, and only one is an open reading frame (ORF) that encodes an uninterrupted polypeptide. We designate this the “5&1” condition. The task for the student is to identify the ORF and “translate” it correctly. Other considerations include correct labeling of the sense and template DNA strands, their 5′ and 3′ ends (and of the mRNA as required), and the amino (N) and carboxyl (C) termini of the polypeptide.Thus, instructors face the logistical challenge of creating dsDNA sequences that satisfy the “5&1” condition for homework and exam questions. Instructors must compose sequences with one or more “stops” in the three overlapping read frames of one strand, while simultaneously creating two “stopped” frames and one ORF in the other. We have explored these constraints as an algorithmic and computational challenge (Carr et al., 2014 ). There are no “5&1” exemplars of length L ≤ 10, and the proportion of exemplars of length L ≥ 11 is very small relative to the 4L possible sequences (e.g., 0.0023% for L = 11, 0.048% for L = 15, 0.89% for L = 25). This makes random exploration for such exemplars inefficient.We therefore developed a two-stage recursive search algorithm that samples 4L space randomly to generate “5&1” exemplars of any specified length L from 11 ≤ L ≤ 100. The algorithm has been implemented as a Web application (“RandomORF,” available at www.ucs.mun.ca/~donald/orf/randomorf). Figure 1 shows a screen capture of the successive stages of the presentation. The application requires JavaScript on the computer used to run the Web browser.Open in a separate windowFigure 1.Successive screen captures of the webapp RandomORF. First panel: the Length parameter is the desired number of base pairs. Second panel: Clicking the “Generate dsDNA” button shows the dsDNA sequence to be solved, with labeled 5′ and 3′ ends. The button changes to “Show ORF.” Third panel: A second click shows the six reading frames, with the ORF highlighted. Here, the ORF is in the sixth reading frame on the bottom (sense) strand. The polypeptide sequence, read right to left, is N–EITHLRL–C, where N and C are the amino and carboxyl termini, respectively. The conventional IUPAC single-letter abbreviations for amino acids are centered over the middle base of the triplet; stop triplets are indicated by asterisks (*).The webapp provides a means for students to practice identifying ORFs by efficiently generating many examples with unique solutions (Supplemental Material); this can take the place of the more standard offering of a small number of set examples with an answer key. The two-stage display makes it possible for problems to be worked “cold,” with the correct ORF identified only afterward. For examinations, any exemplar may be presented in any of four ways, by transposing the top and bottom strands and/or reversing the direction of the strands left to right. Presentation of the 5′ end of the sense strand at the lower left or upper or lower right tests student recognition that sense strands are always read in the 5′→3′ direction, irrespective of the “natural” left-to-right and/or top-then-bottom order. We intend to modify the webapp to include other features of pedagogical value, including constraints on [G+C] composition and the type, number, and distribution of stop triplets. We welcome suggestions from readers.  相似文献   

14.
Students’ epistemological views about biology—their ideas about what “counts” as learning and understanding biology—play a role in how they approach their courses and respond to reforms. As introductory biology courses incorporate more physics and quantitative reasoning, student attitudes about the role of equations in biology become especially relevant. However, as documented in research in physics education, students’ epistemologies are not always stable and fixed entities; they can be dynamic and context-dependent. In this paper, we examine an interview with an introductory student in which she discusses the use of equations in her reformed biology course. In one part of the interview, she expresses what sounds like an entrenched negative stance toward the role equations can play in understanding biology. However, later in the interview, when discussing a different biology topic, she takes a more positive stance toward the value of equations. These results highlight how a given student can have diverse ways of thinking about the value of bringing physics and math into biology. By highlighting how attitudes can shift in response to different tasks, instructional environments, and contextual cues, we emphasize the need to attend to these factors, rather than treating students’ beliefs as fixed and stable.  相似文献   

15.
Instructors attempting new teaching methods may have concerns that students will resist nontraditional teaching methods. The authors provide an overview of research characterizing the nature of student resistance and exploring its origins. Additionally, they provide potential strategies for avoiding or addressing resistance and pose questions about resistance that may be ripe for research study.
“What if the students revolt?” “What if I ask them to talk to a neighbor, and they simply refuse?” “What if they do not see active learning as teaching?” “What if they just want me to lecture?” “What if my teaching evaluation scores plummet?” “Even if I am excited about innovative teaching and learning, what if I encounter student resistance?”
These are genuine concerns of committed and thoughtful instructors who aspire to respond to the repeated national calls to fundamentally change the way biology is taught in colleges and universities across the United States. No doubt most individuals involved in promoting innovative teaching in undergraduate biology education have heard these or variations on these fears and concerns. While some biology instructors may be at a point where they are still skeptical of innovative teaching from more theoretical perspectives (“Is it really any better than lecturing?”), the concerns expressed by the individuals above come from a deeply committed and practical place. These are instructors who have already passed the point where they have become dissatisfied with traditional teaching methods. They have already internally decided to try new approaches and have perhaps been learning new teaching techniques themselves. They are on the precipice of actually implementing formerly theoretical ideas in the real, messy space that is a classroom, with dozens, if not hundreds, of students watching them. Potential rejection by students as they are practicing these new pedagogical skills represents a real and significant roadblock. A change may be even more difficult for those earning high marks from their students for their lectures. If we were to think about a learning progression for faculty moving toward requiring more active class participation on the part of students, the voices above are from those individuals who are progressing along this continuum and who could easily become stuck or turn back in the face of student resistance.Unfortunately, it appears that little systematic attention or research effort has been focused on understanding the origins of student resistance in biology classrooms or the options for preventing and addressing such resistance. As always, this Feature aims to gather research evidence from a variety of fields to support innovations in undergraduate biology education. Below, we attempt to provide an overview of the types of student resistance one might encounter in a classroom, as well as share hypotheses from other disciplines about the potential origins of student resistance. In addition, we offer examples of classroom strategies that have been proposed as potentially useful for either preventing student resistance from happening altogether or addressing student resistance after it occurs, some of which align well with findings from research on the origins of student resistance. Finally, we explore how ready the field of student resistance may be for research study, particularly in undergraduate biology education.  相似文献   

16.
Martin   《Assessing Writing》2009,14(2):88-115
The demand for valid and reliable methods of assessing second and foreign language writing has grown in significance in recent years. One such method is the timed writing test which has a central place in many testing contexts internationally. The reliability of this test method is heavily influenced by the scoring procedures, including the rating scale to be used and the success with which raters can apply the scale. Reliability is crucial because important decisions and inferences about test takers are often made on the basis of test scores. Determining the reliability of the scoring procedure frequently involves examining the consistency with which raters assign scores. This article presents an analysis of the rating of two sets of timed tests written by intermediate level learners of German as a foreign language (n = 47) by two independent raters who used a newly developed detailed scoring rubric containing several categories. The article discusses how the rubric was developed to reflect a particular construct of writing proficiency. Implications for the reliability of the scoring procedure are explored, and considerations for more extensive cross-language research are discussed.  相似文献   

17.
This feature is designed to point CBE---Life Sciences Education readers to current articles of interest in life sciences education as well as more general and noteworthy publications in education research.This feature is designed to point CBE—Life Sciences Education readers to current articles of interest in life sciences education as well as more general and noteworthy publications in education research. URLs are provided for the abstracts or full text of articles. For articles listed as “Abstract available,” full text may be accessible at the indicated URL for readers whose institutions subscribe to the corresponding journal.
  • 1. Freeman S, Eddy SL, McDonough M, Smith MK, Okoroafor N, Jordt H, Wenderoth MP (2014). Active learning increases student performance in science, engineering, and mathematics. Proc Natl Acad Sci USA 111, 8410–8415. [Abstract available at www.pnas.org/content/111/23/8410.abstract]
Online publication of this meta-analysis last spring no doubt launched a legion of local and national conversations about how science is best taught—as the authors state the essential issue, “Should we ask or should we tell?” To assess the relative effectiveness of active-learning (asking) versus lecture-based (telling) methods in college-level science, technology, engineering, and mathematics (STEM) classes, the authors scoured the published and unpublished literature for studies that performed a side-by-side comparison of the two general types of methods. Using five predetermined criteria for admission to the study (described fully in the materials and methods section), at least two independent coders examined each potentially eligible paper to winnow down the number of eligible studies from 642 to 225. The working definition of what constitutes active learning (used to determine potential eligibility) was obtained from distilling definitions written by 338 seminar attendees; what constitutes lecture was defined as “continuous exposition by the teacher” (quoted from Bligh, 2000 ). The eligible studies were situated in introductory and upper-division courses from a full range of enrollment sizes and multiple STEM disciplines and included majors and nonmajors as participants. The frequency of use and types of active-learning methodologies described in the 225 eligible studies varied widely.Quantitative analysis of the eligible studies focused on comparison of two outcome variables: 1) scores on identical or formally equivalent examinations and 2) failure rates (receipt of a “D” or “F” grade or withdrawal from the course). Major findings were that student performance on exams and other assessments (such as concept inventories) was nearly half an SD higher in active-learning versus lecture courses, with an effect size (standardized mean weighted difference) of 0.47. Analyses also revealed that average failure rates were 55% higher for students in the lecture courses than in courses with active learning. Heterogeneity analyses indicated that 1) there were no statistically significant differences in outcomes with respect to disciplines; 2) effect sizes were lower when instructor-generated exams were used versus concept inventories with both types of courses (perhaps because concept inventories tend to require more higher-order thinking skills); 3) effect sizes were not significantly different in nonmajors versus majors courses or in lower versus upper-division courses; and 4) although active learning had the greatest positive effect in smaller-enrollment courses, effect sizes were higher with active learning at all enrollment sizes. Two types of analyses, calculation of fail-safe numbers and funnel plots, supported a lack of publication bias (tendency to not publish studies with low effect sizes). Finally, the authors demonstrated that there were no statistically significant differences in effect sizes despite variation in the quality of the controls on instructor and student equivalence, supporting the important conclusion that the differences in effectiveness between the two methods were not instructor dependent.In one of the more compelling sections of this meta-analysis, the authors translated the relatively dry numbers resulting from statistical comparisons to potential impacts on the lives of the students taking STEM courses. For example, for the 29,300 students reported for the lecture treatments across all students, the average difference in failure rates (21.8% in active learning vs. 33.8% with lecture) suggests that 3516 fewer students would have failed if enrolled in an active-learning course. This and other implications for the more beneficial impact of active learning on STEM students led the authors to state, “If the experiments analyzed here had been conducted as randomized controlled trials of medical interventions, they may have been stopped for benefit.” That is, the control group condition would have been halted because of the clear, beneficial effects of the treatment. The authors conclude by suggesting additional important implications for future undergraduate STEM education research. It may no longer be justified to conduct more “first-generation” research comparing active-learning approaches with traditional lecture; rather, for greater impact on course design, second-generation researchers should focus on what types and intensities of exposure to active learning are most effective for different students, instructors, and topics.This provocative commentary by Carl Weiman highlights the major findings reported in the Proceedings of the National Academy of Sciences by Freeman et al. (2014) and underscores the implications. The graphical representations displaying the key data on effect sizes and failure rates presented in the Freeman et al. meta-analysis are redrawn in the commentary in a way that is likely to be more familiar to the typical reader, making the differences in outcomes for active learning versus lecture appear more striking. Weiman concludes by elaborating on the important implications of the meta-analysis for college-level STEM educators and administrators, suggesting that it “makes a powerful case that any college or university that is teaching its STEM courses by traditional lectures is providing an inferior education to its students. One hopes that it will inspire administrators to start paying attention to the teaching methods used in their classrooms … establishing accountability for using active-learning methods.”National societies, committee reports, and accrediting bodies recommend that engineering curricula be designed to prepare future engineers for the complex interdisciplinary nature of the field and for the multitude of skills and perspectives they will need to be successful practitioners. The authors posit that case-based instruction, with its emphasis on honing skills in solving authentic, interdisciplinary, and ill-defined problems, aligns well with these recommendations. However, the methodology is still relatively underutilized, and its effectiveness is underexamined. This article describes a study designed to advance these issues by comparing lecture- and case-based methods within the same offering of a 72-student, upper-level, required course in mechanical engineering.The study used a within-subjects, posttest only, A-B-A-B research design across four key course topics. That is, two lecture-based modules (the A or baseline phases) alternated with case-based modules (the B or treatment phases). Following each module, students responded to open-response quiz questions and a survey about learning and engagement (adapted from the Student Assessment of Learning Gains instrument). The quiz questions assessed ability to apply knowledge to problem solving (so-called “traditional” questions) and ability to explain the concepts that were used (“conceptual” questions). This study design had the advantage that the same students experienced both the baseline and treatment conditions twice. The authors describe in detail the pedagogical approaches used in both sets of the A and B phases.The quizzes were scored by independent raters (with high interrater reliability) on a 0–3 scale; scores were analyzed using appropriate statistical methods. Survey items were analyzed using a principal-components factor analysis; composite scores were generated for a learning confidence factor and an engagement–connections factor. Analyses revealed that the two pedagogical approaches had similar outcomes with respect to the traditional questions, but conceptual understanding scores (indicating better understanding of the concepts that were applied to problem solving) were significantly higher for the case-based modules. Students reported that they appreciated how cases were better than lecture in helping them make connections to real-world concerns and see the relevance of what they were learning, but there were no significant differences in students’ perceptions of their learning gains in the case-based versus the lecture modules. The authors note that many studies have likewise demonstrated that students’ perceptions of their learning gains in more learner-centered courses are often not accurate reflections of the actual learning outcomes.The authors conclude that while these results are promising indications of the effectiveness of case-based instruction in engineering curricula, the studies need to be replicated across a number of semesters and in different engineering disciplines and extended to assess the long-term effect of case-based instruction on students’ ability to remember and apply their knowledge.Although this study was limited to an engineering context, the case-based methodologies and research design seem well-suited for use in action research in other disciplines.Well-documented challenges to conceptual change faced by students of evolution include the necessity of unseating existing naïve theories (such as natural selection having purposiveness), having the ability to view the complex and emergent nature of evolutionary processes through systems-type thinking, and being able to see the connections between evolutionary content learned in the classroom and everyday life events that can facilitate appreciation of its importance and motivate learning. To help students meet these challenges, the authors adapted a pedagogical model called Teaching for Transformative Experiences in Science (TTES) in the course of instruction on six major concepts in evolutionary biology. This article reports on a comparison of the effectiveness of TTES approaches in fostering conceptual change and positive affect with that of instruction enhanced with use of refutational texts (RT). Use of RTs to promote conceptual change, a strategy with documented effectiveness, entails first stating a misconception (the term used by the authors), then explicitly refuting it by elaborating on a scientific explanation. By contrast, the TTES model promotes teaching that fosters transformative learning experiences—teaching in which instructors 1) place the content in a context allows the students to see its utility or experiential value; 2) model their own transformative experiences in learning course concepts; and 3) scaffold a process that allows students to rethink or “resee” a concept from the perspective of their previous, related life experiences.The authors designed the study to address three questions relevant to the comparison of the two approaches: would the TTES group (vs. the RT group) demonstrate or report 1) greater conceptual change, 2) higher levels of transformative experience, and 3) differences in topic emotions (more positive affect) related to learning about evolution? The study used three survey instruments, one that measured the types and depth of students’ transformative experiences (the Transformative Experience Survey, adapted from Pugh et al., 2010 ), another that assessed conceptual knowledge (Evolutionary Reasoning Scale; Shulman, 2006 ), and a third that evaluated the emotional reactions of students to the evolution content they were learning (Evolution Emotions Survey, derived from Broughton et al., 2011 ). In addition to Likert-scale items, the Transformative Experience Survey contained three open-ended response questions; the responses were scored by two independent raters using a coding scheme for degree of out-of-school engagement. The authors provide additional detail about the nuances of what these instruments were designed to measure and their scoring schemes and include the instruments in the appendices. The Evolutionary Reasoning Scale and the Evolution Emotions survey were administered as both pre- and posttests, and the Transformative Experience survey was administered only at the end of the intervention. The treatment (TTES, n = 28) and comparison (RT, n = 27) groups were not significantly different with respect to all measured demographic variables and the number of high school or college-level science courses taken.Briefly, the evolutionary biology learning experience that participants were exposed to was 3 d in duration for both the treatment and comparison groups. On day 1, the instructor (the same person for both groups) gave a PowerPoint lecture on the same six evolutionary concepts, with illustrative examples. For the treatment group only, the instructor drew from his own transformative experiences in connection with the illustrative examples, describing how he used the concepts, what their value was to him, and how each had expanded his understanding and perception of evolution. On days 2 and 3 for the treatment group, the students and instructor engaged in whole-class discussions about their everyday experiences with evolution concepts (and related misconceptions) and their usefulness; the instructor scaffolded various “reseeing” experiences throughout the discussions. For the comparison group, misconceptions and refutations were addressed in the course of the day 1 lecture, and on days 2 and 3, the participants read refutational texts and then took part in discussions of the texts led by the instructor.Survey results and accompanying statistical analyses indicated that both groups exhibited gains (with significant t statistics) in understanding of the evolution concepts as measured by the Evolutionary Reasoning Scale (Shulman, 2006 ). However, the gains were greater for the treatment (TTES) group: effect size, reported as a value for eta-squared, η2, equaled 0.29. The authors point out by way of context for this outcome that use of RTs, along with follow-up discussions that contrast misconceptions with scientific explanations, has been previously shown to be effective in promoting conceptual change; thus, the comparison was with a well-regarded methodology. Additionally, the Transformation Experience survey findings indicated higher levels of transformative experience for the TTES group participants; they more extensively reported that the concepts had everyday value and meaning and expanded their perspectives. The TTES group alone showed pre- to posttest gains in enjoyment while learning about evolution, a positive emotion that may have classroom implications in terms of receptivity to learning about evolution and willingness to continue study in this and related fields.The authors conclude that the TTES model can effectively engage students in transformative experiences in ways that can facilitate conceptual change in content areas in which that change is difficult to achieve. In discussing possible limitations of the study, they note in particular that the predominance of female study participants (71% of the total) argues for its replication with a more diverse sample.I invite readers to suggest current themes or articles of interest in life sciences education, as well as influential papers published in the more distant past or in the broader field of education research, to be featured in Current Insights. Please send any suggestions to Deborah Allen (ude.ledu@nellaed).  相似文献   

18.
Undergraduate educational settings often struggle to provide students with authentic biologically or medically relevant situations and problems that simultaneously improve their understanding of physics. Through exercises and laboratory activities developed in an elective Physics in Biomedicine course for upper-level biology or pre–health majors at Portland State University, we aim to teach fundamental physical concepts, such as light absorption and emission and atomic energy levels, through analysis of biological systems and medical devices. The activities address the properties of electromagnetic waves as they relate to the interaction with biological tissue and make links between physics and biomedical applications such as microscopy or laser eye surgery. We report on the effect that engaging students in tasks with actual medical equipment has had on their conceptual understanding of light and spectroscopy. These initial assessments indicate that students’ understanding improves in some areas as a result of taking the course, but gains are not uniform and are relatively low for other topics. We also find a promising “nonshift” in student attitudes toward learning science as a result of taking the course. A long-term goal of this work is to develop these materials to the extent that they can eventually be imported into an introductory curriculum for life sciences majors.  相似文献   

19.
Most American colleges and universities offer gateway biology courses to meet the needs of three undergraduate audiences: biology and related science majors, many of whom will become biomedical researchers; premedical students meeting medical school requirements and preparing for the Medical College Admissions Test (MCAT); and students completing general education (GE) graduation requirements. Biology textbooks for these three audiences present a topic scope and sequence that correlates with the topic scope and importance ratings of the biology content specifications for the MCAT regardless of the intended audience. Texts for “nonmajors,” GE courses appear derived directly from their publisher''s majors text. Topic scope and sequence of GE texts reflect those of “their” majors text and, indirectly, the MCAT. MCAT term density of GE texts equals or exceeds that of their corresponding majors text. Most American universities require a GE curriculum to promote a core level of academic understanding among their graduates. This includes civic scientific literacy, recognized as an essential competence for the development of public policies in an increasingly scientific and technological world. Deriving GE biology and related science texts from majors texts designed to meet very different learning objectives may defeat the scientific literacy goals of most schools’ GE curricula.  相似文献   

20.
The conventional noncentrality parameter estimator of covariance structure models, which is currently implemented in widely circulated structural modeling programs (e.g., LISREL, EQS, AMOS, RAMONA), is shown to possess asymptotically potentially large bias, variance, and mean squared error (MSE). A formal expression for its large-sample bias is presented, and its large-sample variance and MSE are quantified. Based on these results, it is suggested that future research needs to develop means of possibly unbiased estimation of the noncentrality parameter, with smaller variance and MSE.  相似文献   

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