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101.
Fourteen behavioral measures were ranked according to their ability to differentiate performances of a wild population of mice from three domestic inbred strains. These “wildness” rankings were then analyzed for their ability to predict genetic and Genotype by Environment interactions. Genetic parameters were derived from analysis of three inbred domestic strains and their three hybrid crosses via the diallel technique of genetic analysis. Genotype by Environment interactions were assessed both as mean differences in stock performances resulting from rearing in a laboratory vs naturalistic environment and as differences in environmental variability within stock genotypes. Behavioral characters ranking high on “wildness” failed to demonstrate any unitary pattern of Genotype by Environment interactions. The diallel genetic analysis revealed many examples of additive variation but relatively few examples of dominant variation. An extremely wide range of interactions occurred between genotype and rearing environments, with “wildness” and “developmental homeostasis” concepts both failing to account for all the observed interactions. 相似文献
102.
How do scores from writing samples generated by computerized essay scorers compare to those generated by “untrained” human scorers and what combination of scores, if any, is more accurate at placing students in composition courses? This study endeavored to answer this two-part question by evaluating the correspondence between writing sample scores generated by the IntelliMetric™ automated scoring system and scores generated by University Preparation English faculty, as well as examining the predictive validity of both the automated and human scores. The results revealed significant correlations between the faculty scores and the IntelliMetric™ scores of the ACCUPLACER™ OnLine WritePlacer Plus test. Moreover, logistic regression models that utilized the IntelliMetric™ scores and average faculty scores were more accurate at placing students (77% overall correct placement rate) than were models incorporating only the average faculty score or the IntelliMetric™ scores. 相似文献
103.
Worldwide there has been a range of initiatives in the area of standards for teachers as part of a discourse of professionalism. In Australia there are a plethora of standards: state and territory frameworks, generic and subject‐specific, systemic and cross‐systemic, for pre‐service, beginning and experienced teachers. Little has been written as to how teacher education programs are responding to the standards agenda. This paper positions standards as integral to the recontextualizing field (Bernstein, 2000) for teacher educators and their programs. Using Bernsteinian concepts of fields, identities and framing, we compare the responses of two physical education teacher education programs to their state's standards imperatives. The authors conclude that the academic orientation of the university, together with the framing of the standards, affect the degree of programmatic change it will undertake in response to the changes in teacher certification standards. 相似文献
104.
Three experiments examined “atomistic” and “configurai” processes in stimulus compounding using the rabbit’s conditioned nictitating membrane response. Two conditioned stimuli (CSs) were trained separately and then tested together in a compound. Animals trained with CSs from different modalities—namely, tone and light—showed summation in both acquisition and extinction. That is, the probability of a response to the compound could be predicted by the statistical sum of responding to the CSs. In contrast, animals trained with CSs from the auditory modality, tone and noise, showed a level of responding to the tone + noise compound that was the same as that of the CSs, well under the level predicted by the statistical sum of responding to the CSs. In conclusion, atomistic processes appear to predominate in cross-modal compounding. Configurai processes may occur during compounding within the auditory modality, but atomistic alternatives—namely, common elements and selective attention hypotheses—may be able to explain the results. 相似文献
105.
This longitudinal study examined how separation and family conflict mediated the effects of two acculturation variables (English language use and generational status) on substance use (alcohol, tobacco, and marijuana use) and deviant behavior outcomes in a Mexican American high school age sample. Structural equation modeling indicated that separation was a significant mediator of the relationship between acculturation and alcohol use, tobacco use, and deviant behavior. Family conflict mediated the effects of acculturation on marijuana use and deviant behavior. Model comparisons across gender groups suggested that generational status was an influential acculturation measure for females but not males. Additionally, English language use maintained a direct effect on marijuana use among females, whereas this relationship was mediated by separation for males. 相似文献
106.
107.
Tree-structured vector quantization (VQ) is a technique designed to represent a codebook that simplifies encoding as well as vector quantizer design. Most design algorithms for tree-structured VQ used in the past are based on heuristics that successively partition the input space. Recently, Chou, Lookabaugh and Gray proposed a tree-pruning heuristic in which a given initial tree is pruned backwards according to certain optimization criterion. We define the notion of an optimal pruned tree subject to a cost constraint and study the computational complexity of finding such an optimal tree for various cost functions. Under the assumption that all trees are equally probable, we show that, on the average, the number of pruned trees in a given tree is exponential in the number of leaves. Furthermore, we prove that finding an optimal pruned tree subject to constraints such as entropy or the expected-depth is NP-hard. However, we show that when the constraint is the number of leaves, the problem can be solved in polynomial time. We develop an algorithm to find the optimal pruned tree in O(nk) time, where n is the size of the initial tree and kis the constraint size. 相似文献
108.
Eric Von Hippel 《Research Policy》1982,11(2):95-115
It has been empirically observed that, in some industries product users are the most frequent sources of product innovations while, in other industries, product manufacturers are. I hypothesize that such differences are caused by differences in the ability of these two “functional” categories of innovators to appropriate innovation benefit. I explore this hypothesis by examining the real-world effectiveness of mechanisms (such as patents and lead time) used for the appropriation of innovation benefit and the dependence of this effectiveness on the functional relationship between innovator and innovation. 相似文献
109.
Students rarely ask questions related to course content in large-format introductory classes. The use of a Web-based forum devoted to student-generated questions was explored in a second-semester introductory biology course. Approximately 80% of the enrolled students asked at least one question about course content during each of three semesters during which this approach was implemented. About 95% of the students who posted questions reported reading the instructor's response to their questions. Although doing so did not contribute to their grade in the course, approximately 75% of the students reported reading questions posted by other students in the class. Approximately 60% of the students reported that the Web-based question-asking activity contributed to their learning of biology. 相似文献
110.
Teachers' education, classroom quality, and young children's academic skills: results from seven studies of preschool programs 总被引:10,自引:0,他引:10
Early DM Maxwell KL Burchinal M Alva S Bender RH Bryant D Cai K Clifford RM Ebanks C Griffin JA Henry GT Howes C Iriondo-Perez J Jeon HJ Mashburn AJ Peisner-Feinberg E Pianta RC Vandergrift N Zill N 《Child development》2007,78(2):558-580
In an effort to provide high-quality preschool education, policymakers are increasingly requiring public preschool teachers to have at least a Bachelor's degree, preferably in early childhood education. Seven major studies of early care and education were used to predict classroom quality and children's academic outcomes from the educational attainment and major of teachers of 4-year-olds. The findings indicate largely null or contradictory associations, indicating that policies focused solely on increasing teachers' education will not suffice for improving classroom quality or maximizing children's academic gains. Instead, raising the effectiveness of early childhood education likely will require a broad range of professional development activities and supports targeted toward teachers' interactions with children. 相似文献