The effect of network size on intra-network knowledge processes     

Donald?HislopEmail author 《知识管理研究与实践》2005,3(4):244-252

This paper addresses a neglected topic in the knowledge management literature: how the size of a network of actors affects the nature of intra-network social relations and knowledge processes. It makes a theoretical contribution to developing understanding in this area drawing on a range of literatures including practice-based perspectives on knowledge, the literature on the embeddedness of social relations, and relevant knowledge management literature. The central focus of this paper is on the relationship between network size, network density, and how these variables affect intra-network knowledge processes. It suggests that as network size increases network density is likely to decrease (as it becomes problematic for the actors in such networks to retain strong ties with a significant proportion of the network's members), which it will be suggested has significant ramifications for intra-network knowledge processes. This paper concludes by reflecting on the implications of the ideas developed for network-based forms of organizing, and innovation processes.  相似文献   

Lifting Titan''s Veil: Exploring the Giant Moon of Saturn     

Donald M. Hunten 《Endeavour》2002,26(4)

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Label-free microfluidic characterization of temperature-dependent biomolecular interactions     

Nguyen T  Pei R  Landry DW  Stojanovic MN  Lin Q 《Biomicrofluidics》2011,5(3):34118-341187

We present a microfluidic approach to characterizing temperature-dependent biomolecular interactions. Solvated L-arginine vasopressin (AVP) and its immobilized RNA aptamer (spiegelmer) were allowed to achieve equilibrium binding in a microchip at a series of selected temperatures. Unbound AVP were collected and analyzed with matrix-assisted laser desorption∕ionization mass spectrometry (MALDI-MS), yielding melting curves that reveal highly temperature-dependent zones in which affinity binding (36–45 °C) or dissociation (25–33 °C and 50–65 °C) occurs. Additionally, temperature-dependent binding isotherms were constructed; from these, thermodynamic quantities involved in binding were extracted. The results illustrated a strong change in heat capacity of interaction for this system, suggesting a considerable thermodynamic influence controlling vasopressin-spiegelmer interaction.  相似文献   

The approximate frequency response of semi-active systems requiring no computer     

Donald L. Margolis 《Journal of The Franklin Institute》1983,316(3):261-271

Semi-active systems are those in which a passive, dissipative element (damper, friction clutch, fluid orifice) is modulated, via low power inputs, to enhance the performance of its associated dynamic system. This type of control is inherently nonlinear, thus forcing the closed-loop response of the total system to be determined numerically using a digital computer. Although, strictly speaking, the frequency response for nonlinear systems does not exist, it is typical to simulate semi-active systems with sinusoidal input and present results as frequency transmissibilities. This paper uses energy dissipation per cycle to determine an approximate frequency response of semi-active systems requiring only a calculator for numerical analysis.  相似文献   

Reading and spelling difficulties in high school students: Causes and consequences     

Donald Shankweiler  Eric Lundquist  Lois G. Dreyer  Cheryl C. Dickinson 《Reading and writing》1996,8(3):267-294

Basic skills in reading and spelling and supporting metalinguistic abilities were assessed in ninth and tenth grade students in two school settings. Students attending a private high school for the learning disabled comprised one group and the other comprised low to middle range students from a public high school. Both the LD students and the regular high school students displayed deficiencies in spelling and in decoding, a factor in reading difficulty that is commonly supposed to dwindle in importance after the elementary school years. Treating the overlapping groups as a single sample, multiple regression analysis was used to investigate the contribution of nonword decoding skill and phonological and morphological awareness to spelling ability. The analysis revealed that decoding was the major component, predicting about half of the variance in spelling. The effect of phonological awareness was largely hidden by its high correlation with decoding, but was a significant predictor of spelling in its own right. Morphological awareness predicted spelling skill when the words to be spelled were morphologically complex. An additional study showed that differences in decoding and spelling ability were associated with differences in comprehension after controlling for reading experience and vocabulary. Even among experienced readers individual differences in comprehension of text reflect efficiency of phonological processing at the word level.  相似文献   

Deafness in sub-Saharan Africa   总被引：1，自引：0，他引：1  

Kiyaga NB  Moores DF 《American annals of the deaf》2003,148(1):18-24

Deaf education in sub-Saharan Africa originated in the 19th century, primarily through efforts by hearing European missionaries who typically followed their homelands' oral-only practices. But education became available to only a fraction of the deaf population. In the 20th century, Andrew Foster, a deaf African American missionary and Gallaudet University's first African American graduate, had unparalleled impact on deaf education in the region, establishing 31 schools for the Deaf, training a generation of deaf leaders, and introducing his concept of Total Communication, which embraced both American and indigenous signs. Nigeria, Kenya, Uganda, and South Africa have provided leadership in deaf education, but throughout the region there is growing acceptance of sign language use in school, and secondary and postsecondary education for the Deaf is increasingly available. Some national constitutions safeguard the rights of citizens with disabilities and even recognize indigenous sign languages. International disability organizations, particularly the World Federation of the Deaf, have helped change attitudes and train leaders. Despite some grim present realities, prospects for continued progress are good.  相似文献   

Renaming experience/reconstructing practice: Developing new understanding of teaching     

Donald Freeman 《Teaching and Teacher Education》1993,9(5-6)

Although teacher-thinking research is now well established, the specific mechanisms through which teachers construct new understandings of their teaching have not been closely examined. This paper presents four interrelated concepts—teachers' conceptions of practice, tensions in their practice, articulation, and local and professional language—which emerged as grounded categories from a longitudinal study of change in teachers' practice. The study focused on how a group of foreign language teachers integrated new ideas, encountered in an inservice masters' degree program, in their thinking about and activity in the classroom. The analysis traced the ways in which the teachers reconstructed their classroom practice, using professional discourse to rename their experience and thus to assign new or different meanings to their actions. The concepts, presented with illustrations from the study and accompanying analysis, have implications for research on teaching and teacher education as well as the design and execution of teacher education programs.  相似文献   

The evaluation of school science departments     

Sally Brown  Donald McIntyre  Ron Impey 《Studies in Educational Evaluation》1979,5(3):175-186

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Effects of stimulus spacing on steady state gradients of inhibitory stimulus control     

Susan M. Essock  Donald S. Blough 《Learning & behavior》1977,5(2):174-176

When the response of pigeons is maintained to a number of stimulus wavelengths, but extinguished to one (S?), the birds peck more rapidly at stimuli near the S? than at more distant stimuli. The present study explores this “dimensional contrast” effect as a function of the number and spacing of test wavelengths. A fixed portion of the wavelength continuum was spanned by 5, 9, 13, or 49 stimuli, which appeared in random sequence behind a standard pecking key. At the end of each 20-sec trial, pecks to test stimuli produced a conditioned reinforcer (sometimes followed by food), while pecks to the S? stimulus produced only darkness. Dimensional contrast “shoulders” developed to test stimuli on either side of the S?; these shoulders were of approximately the same height and wavelength position for all but the 5-stimulus (widely spaced) condition, and were comparable to the original contrast results with 25 stimuli. The results strongly suggest that the extent and locus of contrast shoulders are largely independent of the number and spacing of test stimuli.  相似文献   

Life-science concept development among beginning kindergarten children from three different community settings     

Donald E. Riechard 《科学教学研究杂志》1973,10(1):39-50

Two basic questions were investigated. (1) Do beginning kindergarten children from three different community settings (inner-urban, outer-urban, and rural-farm) vary significantly in performance on a Life-Science Concept Acquisition Test (L-SCAT)? (2) What independent variables are the most useful predictors of performance on the L-SCAT? The L-SCAT was developed by the investigator. It was administered to seventeen subjects from each of the three community settings (N = 51). Among the results were the following: (1) there were significant differences (p < .05) among the scores made by the subjects; (2) a major source of significance was between outer-urban and inner-urban subjects' mean scores; (3) when all physical, mental, and sociocultural variables were used as predictors, a subject's I.Q. and his chronological age were the most useful predictors of L-SCAT performance; and (4) when sociocultural variables alone were used as predictors, the number of years education of a subject's mother was the most useful predictor of L-SCAT performance.  相似文献