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As we travel through life, our journeys offer myriad observations, relationships, and experiences. By chance and choice, our journeys align closely with and are guided by other people's journeys; from these associations we form a sense of our individual cultural characteristics and self-identities. Simultaneously, our journeys follow courses that remain distant and distinct from other people's paths; yet our observations and interpretations from afar also contribute strongly to the formulation of individual cultural characteristics and self-identities. Throughout life's dynamic encounters and events, each of us continues to formulate, reformulate, and negotiate our self-identities as we traverse what seems like parallel paths-journeys that appear distant and distinct from other journeys, yet encountering equally powerful influences shaping our thoughts, beliefs, and actions. Rarely are we afforded the opportunities to investigate these parallel paths and communicate honestly with individuals who seemed far away and foreign; seldom can we truly experience multiple perspectives and cross-cultural relationships in our own journeys. This article presents the unique intersection of two parallel lives and the authentic exchange of multiple perspectives reported through narrative or personal life histories. The authors serendipitously met at a National Association for Multicultural Education (NAME) conference and by chance shared their childhood stories. The authors were raised in similar environments but from opposite lifestyles -lifestyles that paralleled one another and contributed significantly to their individual understanding of cultural characteristics and self-identity. Here they share their histories spanning 50 years while providing insights and guidelines for teachers and teacher educators to learn from our pasts and reshape our futures.     

Acute effects of static stretching on characteristics of the isokinetic angle - torque relationship, surface electromyography, and mechanomyography

The aims of this study were to examine the acute effects of static stretching on peak torque, work, the joint angle at peak torque, acceleration time, isokinetic range of motion, mechanomyographic amplitude, and electromyographic amplitude of the rectus femoris during maximal concentric isokinetic leg extensions at 1.04 and 5.23 rad x s(-1) in men and women. Ten women (mean +/- s: age 23.0 +/- 2.9 years, stature 1.61 +/- 0.12 m, mass 63.3 +/- 9.9 kg) and eight men (age 21.4 +/- 3.0 years, stature 1.83 +/- 0.11 m, mass 83.1 +/- 15.2 kg) performed maximal voluntary concentric isokinetic leg extensions at 1.04 and 5.23 rad x s(-1). Following the initial isokinetic tests, the dominant leg extensors were stretched using four static stretching exercises. After the stretching, the isokinetic tests were repeated. Peak torque, acceleration time, and electromyographic amplitude decreased (P< or = 0.05) from pre- to post-stretching at 1.04 and 5.23 rad . s(-1); there were no changes (P > 0.05) in work, joint angle at peak torque, isokinetic range of motion, or mechanomyographic amplitude. These findings indicate no stretching-related changes in the area under the angle - torque curve (work), but a significant decrease in peak torque, which suggests that static stretching may cause a "flattening" of the angle - torque curve that reduces peak strength but allows for greater force production at other joint angles. These findings, in conjunction with the increased limb acceleration rates (decreased acceleration time) observed in the present study, provide tentative support for the hypothesis that static stretching alters the angle - torque relationship and/or sarcomere shortening velocity.     

The sales effect of word of mouth: a model for creative goods and estimates for novels

Weekly sales of creative goods—like music records, movies, or books—usually peak shortly after release and then decline quickly. In many cases, however, they follow a hump-shaped pattern where sales increase for some time. A popular explanation for this phenomenon is word of mouth among a population of heterogeneous buyers, but previous studies typically assume buyer homogeneity or neglect word of mouth altogether. In this paper, I study a model of new-product diffusion with heterogeneous buyers that allows for a quantification of the sales effect of word of mouth. The model includes Christmas sales as a special case. All parameters have an intuitive interpretation. Simulation results suggest that the parameters are estimable for data that are not too volatile and that cover a sufficiently large part of a title’s life cycle. I estimate the model for four exemplary novels using scanner data on weekly sales.

Die Bedeutung striataler Plastizitätsvorgänge und unerwarteten Bewegungserfolgs für sportmotorisches Lernen

The cortico-basal ganglia loops play an important role in the organization of human motor function. This article presents findings and thoughts according to which plasticity processes in these cortico-striatal loops and in the striatum mediate long-lasting reorganization of cortical motor representations and possess relevance for sport-specific motor activity. The correlations described point to the great significance of unexpected success of motor activity for motor learning processes.     

The roles of professional and trade associations

Under the former Communist regimes, trade associations were often effectively instruments of government. They now have to acquire a new role in the emergent democracies. But trade associations have few resources, are difficult to manage, and are subject to legal restraints. Yet these groups have an enormous job: to act on behalf of their members, to represent them to the government and other groups, and to achieve what they as an industry want and need. This requires that members reach a common position and provide support and assistance. It also requires that the association delegate some activities to commercial operators. A variety of book trade associations is described. Clive Bradley has been chief executive of the British Publishers Association since 1976 and director of the Confederation of Information Communication Industries since 1984. A barrister who studied law at Cambridge and Yale Universities, he has made special studies of the laws of copyright and industrial relations and of European law. This article was adapted from a presentation given at the seminar “East Meets West: Copyright and the Publisher in a Market Economy”, held in Hamburg in March 1991.     

Four spheres of knowledge required: an international study of the professional development of literacy/English teacher educators

This paper reports on a research study of 28 literacy teacher educators (LTE) in four countries: Canada, the USA, England and Australia. It identifies three main forms of professional development: informal, formal and communities of practice and four spheres of knowledge: research; pedagogy of higher education; literacy and literacy teaching; and current school district and government initiatives. The study reveals the sheer scale of knowledge required to be an effective LTE and demonstrates how participants used the three forms of professional development to enhance their knowledge in each sphere. It concludes that the professional development of teacher educators is not conducted systematically; rather, it is quite ad hoc with much of it occurring through learning while doing. All had to construct their own programmes for professional development, which added yet another layer to their responsibilities.     

Development of an Augmented Reality Game to Teach Abstract Concepts in Food Chemistry

One of the most pressing issues for many land grant institutions is the ever increasing cost to build and operate wet chemistry laboratories. A partial solution is to develop computer‐based teaching modules that take advantage of animation, web‐based or off‐campus learning experiences directed at engaging students’ creative experiences. We used the learning objectives of one of the most difficult topics in food chemistry, enzyme kinetics, to test this concept. Students are apprehensive of this subject and often criticize the staid instructional methods typically used in teaching this material. As a result, students do not acquire a useful background in this important subject. To rectify these issues, we developed an interactive augmented reality application to teach the basic concepts of enzyme kinetics in the context of an interactive search that took students to several locations on campus where they were able to gather raw materials and view videos that taught the basics of enzyme kinetics as applied to the production of high fructose corn syrup (HFCS). The students needed this background to prepare for a mock interview with an HFCS manufacturer. Students and instructors alike found the game to be preferable to sitting in a classroom listening to, or giving, a PowerPoint presentation. We feel that this use of gaming technology to teach difficult, abstract concepts may be a breakthrough in food science education and help alleviate the drain on administrative budgets from multiple wet labs.     

Interactions Are Critical

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 posttest_i = 80 + 0.1 × pre-test_i + Ɛ_i, where Ɛ_i was selected from a random normal distribution with mean = 0 (SD = 10). For the control course, posttest values were calculated using the formula posttest_i = 42 + 0.5 × pre-test_i + Ɛ_i, where Ɛ_i 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.