From Scribbles to Scrabble: Preschool Children's Developing Knowledge of Written Language

The purpose of this study was to concurrently examine the development of written language across different writing tasks and to investigate how writing features develop in preschool children. Emergent written language knowledge of 372 preschoolers was assessed using numerous writing tasks. The findings from this study indicate that children demonstrate knowledge about writing before beginning school and receiving formal instruction. There was clear evidence to support the claim that universal writing features develop before language-specific features. Children as young as 3 years possess knowledge regarding universal and language-specific writing features. Preschoolers appear to progress along a continuum from scribbling to conventional spelling. Although this progression is sequential, children’s writing proficiency is task dependent. Implications of these findings on writing development are discussed.     

The role of trial tracking in rats’ working memory

The experiments reported in the present study tested whether decreasing intertrial intervals (ITIs) intensifies the disruptive effects of increasing retention intervals (RIs) in a delayed conditional discrimination by decreasing the animal’s trial tracking accuracy (Cohen & Armstrong, 1996; Cohen & Roberts, 1996). Rats responded on a fixed ratio (FR) 1 or fixed interval (FI) 10-sec reinforcement schedule at a second light or tone stimulus, S2, when the first light or tone stimulus, S1, had signaled an FI 10-sec or FR 1 schedule, respectively. RIs between S1 and S2 were increased from 3 to 24 sec and never exceeded ITIs that were reduced from 24 to 6 sec. For some rats, the trials were separated from each other by extending the lever at S1 and retracting it at the end of S2 (ITI lever-retracted group). For other, control rats, the lever remained extended throughout the session (lever-extended group, Experiment 1) or was extended and retracted with the onset and offset of each stimulus (RI/ITI lever-retracted group, Experiment 2). The rats under all trial conditions learned to delay leverpressing on the FI 10-sec schedule. Latency to begin leverpressing on the FI 10-sec schedule declined as RIs were increased, but this effect was attenuated in the ITI lever-retracted groups in both experiments, as would be predicted by thetrial tracking hypothesis. Decreasing ITIs from 24 to 6 sec intensified the disruptive effects of increasing RIs from 3 to 6 sec in the RI/ITI lever-retracted group (Experiment 2), as would be predicted by the trial tracking hypothesis.     

Gödel’s proof

In 1931, the great Austrian mathematician Kurt Gödel proved “all consistent axiomatic formulations of number theory include undecidable propositions”. This discovery of Gödel and its proof had enormous repercussions in mathematics and computer science. The proof hinged upon the writing of a self-referential mathematical statement, in the same way as the liar’s paradox — I am lying — is a self-referential statement. In this three-part article, we describe Gödel’s discovery and his famous proof.     

Negotiating science and engineering: an exploratory case study of a reform-minded science teacher

Engineering has been slowly integrated into K-12 science classrooms in the United States as the result of recent science education reforms. Such changes in science teaching require that a science teacher is confident with and committed to content, practices, language, and cultures related to both science and engineering. However, from the perspective of the science teacher, this would require not only the development of knowledge and pedagogies associated with engineering, but also the construction of new identities operating within the reforms and within the context of their school. In this study, a middle school science teacher was observed and interviewed over a period of nine months to explore his experiences as he adopted new values, discourses, and practices and constructed his identity as a reform-minded science teacher. Our findings revealed that, as the teacher attempted to become a reform-minded science teacher, he constantly negotiated his professional identities – a dynamic process that created conflicts in his classroom practices. Several differences were observed between the teacher’s science and engineering instruction: hands-on activities, depth and detail of content, language use, and the way the teacher positioned himself and his students with respect to science and engineering. Implications for science teacher professional development are discussed.     

Balancing between deaf and hearing worlds: reflections of mainstreamed college students on relationships and social interaction

This qualitative study of the social aspects of mainstreaming from the perspective of deaf college students indicates that for some students, social adjustment to college is complicated by experiences of separation and alienation from both deaf and hearing peers. Data were collected through open-ended interviews with deaf students who had little or no previous experience with or exposure to deaf culture or language before their arrival at a mainstream college environment. Feelings of isolation, loneliness, and resentment were most intense during orientation and first year, when alienation from the deaf student community appeared to be caused by lack of sign language skills, unfamiliarity with norms and values of deaf culture, and perceived hostility from deaf peers. Simultaneous experiences of separation from hearing peers appeared to be caused by physical barriers inherent in the classroom, residence hall, and cafeteria environments, as well as by discrimination from hearing peers, who tended to stereotype deaf students. Findings suggest that those involved in the administration and delivery of postsecondary programs for the deaf should investigate the experiences of students who arrive on campus without knowledge of sign language or familiarity with deaf culture and evaluate currently existing programs and services designed to meet these students' needs.     

Spacing extinction trials alleviates renewal and spontaneous recovery

Studies of extinction in classical conditioning situations can reveal techniques that maximize the effectiveness of exposure-based behavior therapies. In three experiments, we investigated the effect of varying the intertrial interval during an extinction treatment in a fear-conditioning preparation with rats as subjects. In Experiment 1, we found less fear at test (i.e., more effective extinction) when extinction trials were widely spaced, relative to intermediate or massed extinction trials. In Experiment 2, we used an ABA renewal procedure and observed that spaced trials attenuated renewal of conditioned fear relative to massed trials. In Experiment 3, we used a similar design, but instead of changing the physical context at the time of testing, we interposed a retention interval after the extinction treatment to produce a change in the temporal context. The results showed less spontaneous recovery of fear after spaced than after massed extinction trials. These results suggest that extinction is more enduring when the extinction trials are spaced rather than massed. Although the benefits of spacing trials are small when there is no contextual change from extinction to testing, a change in either physical or temporal context following massed extinction trials leads to a recovery from extinction, which is reduced when the trials are spaced.     

Understanding Leadership in Major Sporting Events: The Case of the 2005 World Aquatics Championships

The purpose of this paper was to begin understanding leadership within a major sporting event. A case study of the 2005 Fédération Internationale de Natation (FINA) World Aquatics Championships was built by means of interviews and archival material, using a multi-stakeholder perspective. Findings highlighted that core elements of upper-management level leadership in events were best described by the multiple-linkage leadership theory, which includes task commitment, ability and role clarity, work organization, cooperation and mutual trust, resources and support, and external coordination as the six intervening variables. While charismatic and transformational leadership styles surfaced as contributing to the overall success of an event, the multiple-linkage leadership theory offered a more comprehensive understanding of leadership in major sporting events from a multi-stakeholder perspective.     

Optimum calibration of a parallel kinematic manipulator using digital indicators

This paper presents a calibration method for parallel manipulators using a measurement system specially installed on an external fixed frame. The external fixed frame is important as an error reference for calibration in certain operations, such as in the configuration of a parallel manip- ulator functioning as a machine tool where the workpiece is fixed to a worktable. The pose of the end-effector is mea- sured using three digital indicators installed on the external fixed frame. To enable measurement, the end-effector is assumed to be a plane large enough that all digital indicators could touch. The error is defined as the difference between the theoretical and actual readings of the digital indicators. The geometric parameters of the parallel manipulator are optimized to minimize this error. This calibration method is low cost and feasible for compensating geometric parameter errors for a parallel manipulator. Optimal pose selection for the calibration is achieved using a swarm intelligence search algorithm. The method is implemented on a prototype of a six degrees-of-freedom （DOFs） Gough-Stewart platform constructed to function as a machine tool.     

Homework: a cross-cultural examination

Cultural differences in the amount of time spent on homework and in beliefs and attitudes about homework were investigated through interviews with more than 3,500 elementary school children, their mothers, and their teachers. The children lived in 5 cities: Beijing, Chicago, Minneapolis, Sendai (Japan), and Taipei. Chinese children were assigned more homework and spent more time on homework than Japanese children, who in turn were assigned more and spent more time on homework than American children. Chinese children also received more help from family members with their homework than American and Japanese children. Chinese children were found to have more positive attitudes about homework than American children; Japanese children's attitudes were between those of the Chinese and American children. Relations between amount of time spent on homework by children, amount of time parents spent assisting their children with homework, and children's achievement were also explored. The views of both parents and teachers about the value of homework are discussed.