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91.
Leonard?A.?AnnettaEmail author James?Minogue 《Journal of Science Education and Technology》2004,13(4):485-494
The first year of a 5 year professional development project for elementary teachers in two mid-western states integrated a bridge of two distinctly different distance education networks (T-1 and fiber optics) to provide science professional development for elementary school teachers in rural communities. Interactive television (ITV), the title given to the distance component, consisted of a series of twenty-four, 2 h presentations by scientists and content specialists. It provided expansion to the science pedagogical content knowledge of the elementary teachers involved. Eighty-five teachers in 38 school districts from the two states completed individual surveys following the final ITV session. Analysis of variance of participants post-session survey scores yielded differences (p < 0.05) on the subscales measuring perceived effectiveness of using distance education for professional development purposes and years of teaching experience. Teachers with over 20 years of classroom experience perceived the use of distance education technologies for science professional development to be more effective than teachers with 16–20 years of classroom experience. These results might suggest another digital divide. 相似文献
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Chia-Jung Lee ChanMin Kim 《Educational technology research and development : ETR & D》2017,65(6):1627-1654
This paper presents the third version of a technological pedagogical content knowledge (TPACK) based instructional design model that incorporates the distinctive, transformative, and integrative views of TPACK into a comprehensive actionable framework. Strategies of relating TPACK domains to real-life learning experiences, role-playing, and teachers as designers were developed based on the three views and integrated into the third version of the model. The model was then applied in a teacher education undergraduate course on technology integration. A case study approach was used. Data were collected from the participants’ discussion worksheets, lesson designs, and the researchers’ field observation notes. Data analysis results suggest that the strategies integrated into the model helped the participants deepen their understanding of student-centered technology applications and practice TPACK. Findings, implications, and future research possibilities are discussed. 相似文献
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Luciferase from firefly lantern extract was immobilized on CNBr-activated Sepharose 4B. The kinetic properties of immobilized
luciferase were extensively studied. TheK
m′ for D-luciferin is 11.9 μmol/L, the optimum pH and temperature for Sepharose-bound enzyme were 7.8 and 25°C respectively.
A luminescence fiber optic biosensor, making use of immobilized crude luciferase, was developed for assay of ATP. The peak
light intensity was linear with respect to ATP concentration in range of 10−9–10−5 mol/L. A biological application was also demonstrated with the determination of serum ATP from rats bred in low versus normal
oxygen environments. 相似文献
97.
Eun-hye Park Won-young Bae Jae-yeon Kim Kee-tae Kim Hyun-dong Paik 《Journal of Zhejiang University. Science. B》2017,18(9):816-824
The inhibitory effects of Lactobacillus plantarum-fermented and non-fermented Inula britannica extracts on the tyrosinase activity were comparatively investigated to examine whether and how they improve the whitening activity, and the contents of total flavonoids and polyphenolics as bioactive compounds were determined. The skin whitening activity using in vitro or ex vivo tyrosinase and L-3,4-dihydroxyphenylalanine (L-DOPA) staining was examined. The total flavonoid content (TFC) was increased by 13.4% after 72 h-fermentation. The viabilities of the B16F10 cells treated with the fermented and non-fermented control extracts were 100.26% and 92.15% at 500 μg/ml, respectively. In addition, the inhibition of tyrosinase activity was increased by the fermented samples from 29.33% to 41.74% following fermentation for up to 72 h. The tyrosinase activity of the untreated control group was increased to 145.69% in B16F10 cells. The results showed that I. britannica fermented by L. plantarum dose-dependently inhibited tyrosinase activity, which was stimulated by α-melanocyte stimulating hormone. These results suggest that lactic fermented I. britannica extracts can be used as effective skin-whitening materials. 相似文献
98.
Pedagogical Agents as Learning Companions: The Role of Agent Competency and Type of Interaction 总被引:1,自引:0,他引:1
Yanghee Kim Amy L. Baylor 《Educational technology research and development : ETR & D》2006,54(3):223-243
This study was designed to examine the effects of the competency (low vs. high) and interaction type (proactive vs. responsive)
of pedagogical agents as learning companions (PALs) on learning, self-efficacy, and attitudes. Participants were 72 undergraduates
in an introductory computer-literacy course who were randomly assigned to one of four treatments: Low-Proactive, Low-Responsive,
High-Proactive, and High-Responsive. Results indicated a main effect for PAL competency. Students who worked with the high-competency
PAL in both proactive and responsive conditions achieved higher scores in applying what they had learned and showed more positive
attitudes toward the PAL. However, students who worked with the low-competency PAL reported significantly enhanced self-efficacy
beliefs in the learning tasks. Also, there was a main effect far PAL interaction type. A proactive PAL had a significantly
positive impact on recall. These different results on learning and motivational outcomes suggest that the competency and interaction
type of a PAL should be designed according to the desired learning and motivational goals. 相似文献
99.
An efficient method for tracing planar implicit curves 总被引:1,自引:0,他引:1
YU Zheng-sheng CAI Yao-zhi OH Min-jae KIM Tae-wan PENG Qun-sheng 《浙江大学学报(A卷英文版)》2006,7(7):1115-1123
INTRODUCTION Tracing a planar implicit curve f(x, y)=0 on a rectangular region [xl, xr]×[yb, yt] is of great interest in Computer-Aided Design and Computer Graphics. While parametric curves are easy to plot, plotting implicit curves is a challenging problem. Planar im- plicit curve plotting method can be classified into two categories (Shou et al., 2005; Martin et al., 2002; Lopes et al., 2002). In the first category are subdivi- sion methods (Shou et al., 2005; Martin et al., 2002) … 相似文献
100.