David F. Treagust: congenial soul, science educator, and international research leader

For almost a half century David F. Treagust has been an exemplary science educator who has contributed through his dedication and commitments to students, curriculum development and collaboration with teachers, and cutting edge research in science education that has impacted the field globally, nationally and locally. A hallmark of his outstanding career is his collaborative style that inspires others to produce their best work.     

Perceptions of Retirement Affect Career Commitment: The Mediating Role of Retirement System Satisfaction for Two Teacher Age Groups

This study investigated a sample of California elementary, intermediate, and high school employed teachers (N = 247) to assess the effects of retirement perceptions on career commitment among teachers who are in different age groupings. Using path analysis, the influence of five retirement perceptions variables was examined: concerns about retirement benefits, understanding of the retirement system, perceived need for system change, control over the retirement plan, and satisfaction with current salary. The results indicated that the pattern of results differed for younger and older teachers. For the younger (age 21–45) group, concerns about retirement benefits (such as losing or reducing benefits through geographic mobility) and control over the retirement plan had significant, large, and direct effects on career commitment. For the older (age 46+) group, retirement variables had a significant effect on career commitment via the mediator of satisfaction with the retirement system. Given these findings, for younger teachers, strategies might focus on providing greater control over the retirement plan, such as in offering choice in how their retirement monies are invested. Older teachers need to feel safe about retirement in the sense of being satisfied with the system and its benefits to commit to their jobs.     

Anxiety and the Use of Alcohol‐Related Protective Behavioral Strategies

Protective behavioral strategies (PBS) are useful skills for reducing the negative consequences of alcohol. The moderating effects of anxiety on the relationship between 3 different types of PBS and negative consequences were examined among students accessing college counseling services. Results revealed a significant interaction between anxiety and strategies while drinking, suggesting that these simple strategies may be particularly beneficial among students who drink heavily and experience high levels of anxiety. Implications for counseling centers are discussed.     

Musculoskeletal stiffness during hopping and running does not change following downhill backwards walking

Eccentric contractions that provide spring energy can also cause muscle damage. The aim of this study was to explore leg and vertical stiffness following muscle damage induced by an eccentric exercise protocol. Twenty active males completed 60 minutes of backward-walking on a treadmill at 0.67 m/s and a gradient of ? 8.5° to induce muscle damage. Tests were performed immediately before; immediately post; and 24, 48, and 168 hours post eccentric exercise. Tests included running at 3.35 m/s and hopping at 2.2 Hz using single- and double-legged actions. Leg and vertical stiffness were measured from kinetic and kinematic data, and electromyography (EMG) of five muscles of the preferred limb were recorded during hopping. Increases in pain scores (over 37%) occurred post-exercise and 24 and 48 hours later (p < 0.001). A 7% decrease in maximal voluntary contraction occurred immediately post-exercise (p = 0.019). Changes in knee kinematics during single-legged hopping were observed 168 hours post (p < 0.05). No significant changes were observed in EMG, creatine kinase activity, leg, or vertical stiffness. Results indicate that knee mechanics may be altered to maintain consistent levels of leg and vertical stiffness when eccentric exercise-induced muscle damage is present in the lower legs.     

A Criterion-Referenced Approach to Student Ratings of Instruction

We developed a criterion-referenced student rating of instruction (SRI) to facilitate formative assessment of teaching. It involves four dimensions of teaching quality that are grounded in current instructional design principles: Organization and structure, Assessment and feedback, Personal interactions, and Academic rigor. Using item response theory and Wright mapping methods, we describe teaching characteristics at various points along the latent continuum for each scale. These maps enable criterion-referenced score interpretation by making an explicit connection between test performance and the theoretical framework. We explain the way our Wright maps can be used to enhance an instructor’s ability to interpret scores and identify ways to refine teaching. Although our work is aimed at improving score interpretation, a criterion-referenced test is not immune to factors that may bias test scores. The literature on SRIs is filled with research on factors unrelated to teaching that may bias scores. Therefore, we also used multilevel models to evaluate the extent to which student and course characteristic may affect scores and compromise score interpretation. Results indicated that student anger and the interaction between student gender and instructor gender are significant effects that account for a small amount of variance in SRI scores. All things considered, our criterion-referenced approach to SRIs is a viable way to describe teaching quality and help instructors refine pedagogy and facilitate course development.     

Impaired acuity of the approximate number system underlies mathematical learning disability (dyscalculia)

Many children have significant mathematical learning disabilities (MLD, or dyscalculia) despite adequate schooling. The current study hypothesizes that MLD partly results from a deficiency in the Approximate Number System (ANS) that supports nonverbal numerical representations across species and throughout development. In this study of 71 ninth graders, it is shown that students with MLD have significantly poorer ANS precision than students in all other mathematics achievement groups (low, typically, and high achieving), as measured by psychophysical assessments of ANS acuity (w) and of the mappings between ANS representations and number words (cv). This relation persists even when controlling for domain-general abilities. Furthermore, this ANS precision does not differentiate low-achieving from typically achieving students, suggesting an ANS deficit that is specific to MLD.     

传统制造业集群协同演进机制探析——天津自行车集群纵向案例研究

产业集群对区域乃至国家经济发展具有重要的作用,然而产业集群发展过程中的影响因素及其相互作用机制至今仍未得到系统的阐述.从协同演进理论视角,结合组织生态学、制度理论、战略管理理论和社会网络理论等,对天津自行车产业集群的发展历程展开多层次、时间序列的分析,以深入挖掘产业集群发展过程中各种要素的相互作用、协同演进机制,提出产业集群的发展是企业战略、产业环境以及制度环境协同演进的过程,同时集群发展过程中创业者的社会资本发挥重要作用.这种将多维理论视角相结合起来进行分析的方法,有利于更好地理解产业集群的演进机制.     

Benzodiazepine administration prevents the use of error-correction mechanisms during fear extinction

Three experiments examined the effect of systemic administration of the benzodiazepine midazolam on extinction and re-extinction of conditioned fear. Experiment 1 demonstrated that midazolam administration prior to extinction of a conditioned stimulus (CS) impaired that extinction when rats were subsequently tested drug free; however, extinction was spared if rats were extinguished, reconditioned, and re-extinguished under midazolam. Experiment 2 provided a replication of this effect within-subjects; rats were conditioned to two CSs (A and B), extinguished to one (A-), reconditioned to both, and then extinguished/re-extinguished to both stimuli in compound (AB-), under either vehicle or midazolam. On the drug-free test, rats given midazolam froze more to the CS that had been extinguished (B) than the one that been re-extinguished (A). The final experiment examined whether extinction under midazolam was regulated by prediction error. Rats were trained with three CSs (A, B, C) and extinguished to two (A-, C-). These stimuli then underwent additional extinction under midazolam or vehicle, with one CS now presented in compound with the non-extinguished CS (AB-, C-). Rats were then tested for fear of A relative to C. Rats given vehicle showed a deepening of extinction to A relative to C, as is predicted from error-correction models; however, rats given midazolam failed to show any such discrepancy in responding. The results are interpreted to indicate that the drug reduced prediction error during extinction by reducing fear, and rats were able to re-extinguish fear via a retrieval mechanism that is independent of prediction error.