Ethene/norbornene copolymerization by [Me2Si(3-tertBuCp)(NtertBu)]TiCl2/MAO-catalyst     

Tran  Phu-Dennis  Kaminsky  Walter 《浙江大学学报(A卷英文版)》2003,4(2):121-130

Ethene/norbornene copolymerization by the catalyst system [Me₂Si(3-^tertBuCp)(N^tertBu)]TiCl₂/MAO was investigated in detail at 30 °C, 60 °C, and 90 °C. A mass flow controller was used in this work to obtain kinetic data and investigate temperature's effects on activity, norbornene incorporation, copolymerization parameter, microstructure, glass transition temperature, and molar masses were described. High copolymerization valuesr _ξ and high alternation are determined. The number of isotactic alternating sequences is much higher than that of the syndiotactic alternating sequences.  相似文献   

An Internet-Based Course: Leadership Issues     

Walter  L. James  Liu  Daonian  Brooks  David W. 《Journal of Science Education and Technology》1999,8(2):151-154

It comes as no surprise that persons in leadership roles face many decisions related to providing distance learning experiences, especially ones centered on the Internet. In this paper we will try to focus upon leadership issues that arose during the creation and offering of an Internet-based course for high school chemistry teachers. One of us served as the department chair, another as the professor of record and course designer, and the third as a researcher who developed a systematic case study of the course.  相似文献   

Can Examinees Use a Review Option to Obtain Positively Biased Ability Estimates on a Computerized Adaptive Test?     

Walter P. Vispoel  Thomas R. Rocklin  Tianyou Wang  Timothy Bleiler 《Journal of Educational Measurement》1999,36(2):141-157

Part of the controversy about allowing examinees to review and change answers to previous items on computerized adaptive tests (CATs) centers on a strategy for obtaining positively biased ability estimates attributed to Wainer (1993) in which examinees intentionally answer items incorrectly before review and to the best of their abilities upon review. Our results, based on both simulated and live testing data, showed that there were instances in which the Wainer strategy yielded inflated ability estimates as well as instances in which it yielded deflated ability estimates. The success of the strategy in inflating ability estimates depended on the ability estimation method used (maximum likelihood versus Bayesian), the examinee's true ability level, the standard error of the ability estimate, the examinee's ability to implement the strategy, and the type of decision made from the ability estimate. We discuss approaches to dealing with the Wainer strategy in operational CAT settings.  相似文献   

Individualization of data-segment-related parameters for improvement of EEG signal classification in brain-computer interface     

曹红宝  BESIO  Walter  G  JONES  Steven  周鹏 《天津大学学报(英文版)》2010,16(3):235-238

In electroencephalogram (EEG) modeling techniques, data segment selection is the first and still an important step. The influence of a set of data-segment-related parameters on feature extraction and classification in an EEG-based brain-computer interface (BCI) was studied. An auto search algorithm was developed to study four datasegment-related parameters in each trial of 12 subjects’ EEG. The length of data segment (LDS), the start position of data (SPD) segment, AR order, and number of trials (NT) were used to build the model. The study showed that, compared with the classification ratio (CR) without parameter selection, the CR was increased by 20% to 30% with proper selection of these data-segment-related parameters, and the optimum parameter values were subject-dependent. This suggests that the data-segment-related parameters should be individualized when building models for BCI.  相似文献   

Research in Food Science Education: Measuring Gains in Critical Thinking in Food Science and Human Nutrition Courses: The Cornell Critical Thinking Test,Problem‐Based Learning Activities,and Student Journal Entries     

Wayne T. Iwaoka  Yong Li  Walter Y. Rhee 《Journal of Food Science Education》2010,9(3):68-75

Abstract: The Cornell Critical Thinking Test (CCTT) is one of the many multiple‐choice tests with validated questions that have been reported to measure general critical thinking (CT) ability. One of the IFT Education Standards for undergraduate degrees in Food Science is the emphasis on the development of critical thinking. While this skill is easy to list as a student‐learning objective, measuring gains in CT is relatively difficult. If the majority of the class time is spent discussing and solving ill‐defined problems, then will students become actively and meaningfully involved in their own learning and will there be any gains in CT skills? To measure gains using this format, the CCTT was administered as a pre‐ and posttest to Food Science and Human Nutrition students in an Experimental Foods class taught every fall over an 8 y period (2001–2008). Statistical analysis indicated that in 2 of the years (2002 and 2004), there were significant gains (P values 0.036 and 0.045, respectively) in CT scores. Furthermore, in both years, there were significant gains in the same 2 aspects of CT (deduction and assumption) and not in the other aspects. However, we suggest that completing several take‐home exams with many open‐ended questions, writing detailed laboratory reports, and documenting unsolicited student reflections in journal entries that comment on apparent gains in CT skills may be a better indication of actual gains in CT skills compared to the actual CCTT test scores.  相似文献   

Blueprint for Bologna: University of Prishtina and the European Union     

Juanita Ross Epp  Walter Epp 《Interchange》2010,41(2):161-170

Countries hoping to demonstrate an adequate educational infrastructure need a national framework that meets Bologna requirements, a national accreditation agency which sets out the approved framework, and national accreditation processes by which individual institutions can be measured against the standards set by the national acvcreditation agency. For many countries, the national framework remains to be articulated, the accreditation processes are non-existent, and individual institutions have no means by which to assess their internal readiness for accreditation scrutiny. While the status of Kosovo as a separate entity remains unresolved, the institutions within the potential country struggle to meet the infrastructure conditions necessary for inclusion in the European Union. Ironically, the Faculty of Education at the University of Prishtina is in a remarkably advantageous position if it were to overcome the current political bickering and start the preparations required for meeting the education infrastructure criteria. This paper articulates that advantage by laying out the process by which this could be realized – with optimistic disregard for the political uncertainties that mitigate against its realization. It also provides a summary of the tasks that would need to be undertaken as part of this process.  相似文献   

Fluctuation – a common but neglected pattern of physical activity behaviour: An exploratory review of studies in recent 20 years     

Borui Shang  Wendy Yajun Huang  Walter Brehm 《European Journal of Sport Science》2018,18(2):266-278

Background: Regular physical activity (PA) is beneficial for physical and psychological well-being, yet many people do not achieve these health benefits due to irregular PA participation which is also known as fluctuation. Limited attention has been given to the phenomenon of fluctuation in the PA behaviour literature. Objective: The aim of this review was to explore and to map definitions, measurements, behavioural evidence, and factors related to PA fluctuation. Methods: Eligible studies were initially identified by a systematic search of articles conducted in four databases: Scopus, PubMed, PsycINFO, and SPORTDiscus between January 1996 and March 2016. Inclusion and exclusion criteria were set to check the eligibility of all articles. Additional articles were included by manual searching and expert recommendation. Results: Fifteen articles were finally included. Definitions of fluctuation are understood from two perspectives, either as a stage in the process of behaviour change, or as a particular PA phenomenon consisting of lapse and readoption. Common features were extracted: behavioural irregularity, high risk of drop-out, intention and readiness for PA, low automaticity, and limited self-regulation. Furthermore, fluctuation identification was summarised in three approaches such as stage algorithm, self-identified PA lapse and readoption, and prospective within-person variation in meeting the PA guidelines. Regarding the empirical evidence, this review found that people in PA fluctuation were significantly distinct from those in preparation and maintenance of PA behavioural performance, as well as distinct in psychosocial features. Conclusions: Notwithstanding the limitations, this review has provided valuable insight into the phenomenon of PA fluctuation.  相似文献   

A citation and co-citation analysis of 10 years of KM theory and practices     

Christian?Walter  Vincent?RibièreEmail author 《知识管理研究与实践》2013,11(3):221-229

In a previous issue of Knowledge Management Research & Practice (KMRP), we analysed the content and keywords of all articles published in the first decade of KMRP. With this article, we extend our preliminary analysis to the citation and co-citations made by these articles. The study covers all the 256 articles published. The most cited article was A dynamic theory of organisational knowledge creation by Nonaka. The most cited KMRP article was by Nonaka and Toyama: The knowledge-creating theory revisited: knowledge creation as a synthesizing process. The co-citation analysis of the 100 most cited articles in KMRP publications showed that four groups of topics emerged, one around communities and situated learning, the second group around networks, knowledge transfer and research methods, a third group around the foundations of knowledge management and a fourth group around intellectual capital.  相似文献   

Psychological Scaling of AIAW Code of Ethics for Coaches     

Walter Kroll 《Research quarterly for exercise and sport》2013,84(1):233-238

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A Better Way to Begin Again Together: the value of a comparative approach to teaching poetry in school     

Colin Walter 《欧洲师范教育杂志》1993,16(2):179-190

This paper suggests a particular value to treating the teaching of poetry in school comparatively. It argues that the justification for this claim derives from the ways in which peculiar symbiotic dependencies between poetry, languages, cultures and uniquely individual consciousness‐‐and between poetry, childhood learning and children's achievement of literacy‐‐can be represented in a teaching methodology. It refers to a unique teaching and research project, directed by the author at Goldsmiths’ College, University of London, which has developed principles and strategies for building a new pedagogy with children and in teacher education.  相似文献