Science,Technology, Engineering,and Mathematics (STEM) Pathways: High School Science and Math Coursework and Postsecondary Degree Attainment     

Will Tyson  Reginald Lee  Kathryn M. Borman  Mary Ann Hanson 《Journal of Education for Students Placed at Risk》2013,18(3):243-270

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CROSS-CULTURAL COMPARISON OF PERCEPTIONS ON THE GLOBAL SCIENTIFIC LITERACY WITH AUSTRALIAN,CHINESE, AND KOREAN MIDDLE SCHOOL STUDENTS     

Mun  Kongju  Lee  Hyunju  Kim  Sung-Won  Choi  Kyunghee  Choi  Sung-Youn  Krajcik  Joseph S. 《International Journal of Science and Mathematics Education》2013,13(2):437-465

In this study, we explored the extent to which Australian, Chinese, and Korean middle school students perceived themselves to have scientific literacy as global citizens and attempted to identify differences and/or commonalities in their perceptions. A total of 655 middle school students (8th and 9th grades; 358 girls and 297 boys) from the three countries participated in the study. We used Global Scientific Literacy Questionnaires (GSLQ) as a survey instrument to assess the students’ perceptions. The GSLQ was developed based on a conceptual framework of Scientific Literacy suggested by Choi, Kim, Lee, Mun, Choi, Krajcik & Shin (2011) and Choi, Lee, Shin, Kim & Krajcik (Journal of Research in Science Teaching, 48(6), 670–697, 2011) for citizenship education in the 21st century. The results indicated that most of the students from the three countries showed a tendency toward higher scores for Science as human endeavor; the lowest scores were in Meta-cognition and self-direction. A pattern of gender difference was also examined among the three countries. We suggest future research questions based on a cross-cultural perspective in order to explore the reasons for the existence of these similarities and differences.

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Utilizing local evidence for blog feed search     

Yeha Lee  Seung-Hoon Na  Jong-Hyeok Lee 《Information Retrieval》2012,15(2):157-177

Blog feed search aims to identify a blog feed of recurring interest to users on a given topic. A blog feed, the retrieval unit for blog feed search, comprises blog posts of diverse topics. This topical diversity of blog feeds often causes performance deterioration of blog feed search. To alleviate the problem, this paper proposes several approaches based on passage retrieval, widely regarded as effective to handle topical diversity at document level in ad-hoc retrieval. We define the global and local evidence for blog feed search, which correspond to the document-level and passage-level evidence for passage retrieval, respectively, and investigate their influence on blog feed search, in terms of both initial retrieval and pseudo-relevance feedback. For initial retrieval, we propose a retrieval framework to integrate global evidence with local evidence. For pseudo-relevance feedback, we gather feedback information from the local evidence of the top K ranked blog feeds to capture diverse and accurate information related to a given topic. Experimental results show that our approaches using local evidence consistently and significantly outperform traditional ones.  相似文献   

The era of incremental change in the technology innovation life cycle: An analysis of the automotive emission control industry     

Jaegul Lee  Nicholas Berente 《Research Policy》2013

According to the life cycle model of technological evolution, after the emergence of a dominant design, technological product industries undergo an “era of incremental change.” This era of incremental change is not well understood in the existing literature. Although the period is typically characterized in terms of stability and minimal innovation, we find that the era of incremental change can be actually quite dynamic. Through our research into the period of time following the emergence of a dominant design in automotive emission control systems, we find that the overall product innovation in the industry did not decline immediately following the dominant design, and increased throughout the era of incremental change. Further, we find that firms maintain their attention on the same core components that they innovated upon before the dominant design, but that these components make up less of the overall proportion of total innovation throughout the era of incremental change. Finally, we found that the concentration of innovating firms in the industry increases immediately following the dominant design, and this concentration decreases over time throughout the era of incremental change. Findings imply a pattern of contraction and expansion in the era of incremental change that extends previous work on the technological product life cycles and helps to characterize the era of incremental change in a novel way.  相似文献   

A mixed methods approach to electronic word-of-mouth in the open-market context     

So-Hyun Lee  Seung-Eui Noh  Hee-Woong Kim 《International Journal of Information Management》2013

Electronic word-of-mouth (eWOM) has been identified as a key factor affecting online sales. However, the factors leading to eWOM in the open-market context are not fully understood. Since many Internet vendors have adopted the open-market business model, it is essential to understand the factors for eWOM leading to the success of open-market business. This study investigates factors affecting eWOM in the open-market context based on a sequential combination of qualitative and quantitative research methods. The exploratory findings in the qualitative study form the basis for the quantitative study survey research. The findings from this mixed methods study indicate the significance of three new factors (information-sharing desire, self-presentation desire, and open-market reward) and two established factors (open-market satisfaction and open-market loyalty) affecting eWOM directly and indirectly. This study makes a useful contribution to the broader literature on eWOM. These findings also inform open-market providers as to how to promote and manage eWOM for online business success.  相似文献   

The role of governance effectiveness in explaining IT outsourcing performance     

Yong Jin Kim  Jong Man Lee  Chulmo Koo  Kichan Nam 《International Journal of Information Management》2013

Recent studies on IT outsourcing have examined the effect of contract specification and relationship strength on IT outsourcing performance in a separate manner. Previous studies, however, ignored the importance of the governance effectiveness that bonds contractual control and relationship strength together to deliver expected outcomes in IT outsourcing exchange. In this paper, we propose a model of IT outsourcing management where governance effectiveness mediates the effect of both contractual control and relationship strength on IT outsourcing performance. We collected data from 143 client companies of IT outsourcing and analyzed it using the PLS method. Our findings show that both contract specification and relationship strength significantly influence governance effectiveness, although contract specification carries the more effect on governance effectiveness than relationship strength does. The governance effectiveness in turn mediates the effect of contract specification and relationship strength on three sub-dimensions of outsourcing performance: cost efficiency, performance improvement, and overall satisfaction. The results and implications are further discussed.  相似文献   

Selective dynamic concentration of peptides at poles of cation-selective nanoporous granules     

Hsiao-Ping Chen  Chia-Chun Tsai  Hung-Meng Lee  Shau-Chun Wang  Hsueh-Chia Chang 《Biomicrofluidics》2013,7(4)

The authors exposed a non-equilibrium dynamic counterion and coion analyte concentration to an AC electric field to selectively concentrate peptides at the poles of a cation-selective granule. The counterion polarization results from the focusing of the electric field show a discontinuous drop in the intra-granule counterion electromigration flux at the pole. The coion concentration polarization is due to the combined external convective and electromigration fluxes toward the pole that neutralize the accumulating counterions. Because the electromigration mobility of the peptide anion analyte depends on the pH, the authors determined a 20 000-fold high concentration factor for a near-neutral pH of 6.0 to 7.7. Because the peptide is protonated at the acidic pole and its absolute charge ranges from −0.3 to −1.9, the concentration factor scales exponentially with the absolute charge, thus allowing extremely selective concentrations of various peptides, which is demonstrated by fluorescein isothiocyanate tagged angiotensin I (pI ∼ 5.8) and Texas red tagged avidin (pI ∼ 10.5). This dynamic concentration effect can substantially enhance the sensitivity of bio-assays.  相似文献   

Parallel generation of uniform fine droplets at hundreds of kilohertz in a flow-focusing module     

David Bardin  Michael R. Kendall  Paul A. Dayton  Abraham P. Lee 《Biomicrofluidics》2013,7(3)

Droplet-based microfluidic systems enable a variety of biomedical applications from point-of-care diagnostics with third world implications, to targeted therapeutics alongside medical ultrasound, to molecular screening and genetic testing. Though these systems maintain the key advantage of precise control of the size and composition of the droplet as compared to conventional methods of production, the low rates at which droplets are produced limits translation beyond the laboratory setting. As well, previous attempts to scale up shear-based microfluidic systems focused on increasing the volumetric throughput and formed large droplets, negating many practical applications of emulsions such as site-specific therapeutics. We present the operation of a parallel module with eight flow-focusing orifices in the dripping regime of droplet formation for the generation of uniform fine droplets at rates in the hundreds of kilohertz. Elevating the capillary number to access dripping, generation of monodisperse droplets of liquid perfluoropentane in the parallel module exceeded 3.69 × 10⁵ droplets per second, or 1.33 × 10⁹ droplets per hour, at a mean diameter of 9.8 μm. Our microfluidic method offers a novel means to amass uniform fine droplets in practical amounts, for instance, to satisfy clinical needs, with the potential for modification to form massive amounts of more complex droplets.  相似文献   

Evaluating the Prediction of Maximal Heart Rate in Children and Adolescents     

Anthony D. Mahon  Andrea D. Marjerrison  Jonah D. Lee  Megan E. Woodruff  Lauren E. Hanna 《Research quarterly for exercise and sport》2013,84(4):466-471

In this study, we compared measured maximal heart rate (HRmax) to two different HRmax prediction equations [220 — age and 208 — 0.7(age)] in 52 children ages 7-17 years. We determined the relationship of chronological age, maturational age, and resting HR to measured HRmax and assessed seated resting HR and HRmax during a graded exercise test. Maturational age was calculated as the maturity offset in years from the estimated age at peak height velocity. Measured HRmax was 201 ± 10 bpm, whereas predicted HRmax ranged from 199 to 208 bpm. Measured HRmax and the predicted value from the 208 — 0.7(age) prediction were similar but lower (p < .05) than the 220 — age prediction. Absolute differences between measured and predicted HRmax were 8 ± 5 and 10 ± 8 bpm for the 208 — 0.7 (age) and 220 — age equations, respectively, and were greater than zero (p < .05). Regression equations using resting HR and maturity offset or chronological age significantly predicted HRmax, although the R2 < .30 and the standard error of estimation (8.2-8.5) limits the accuracy. The 208 — 0.7(age) equation can closely predict mean HRmax in children, but individual variation is still apparent.  相似文献   

Effect of a Prolonged Altitude Expedition on Glucose Tolerance and Abdominal Fatness     

Mu-Tsung Chen  Wen-Chih Lee  Shih-Chang Chen  Chiu-Chou Chen  Chung-Yu Chen  Shin-Da Lee 《Research quarterly for exercise and sport》2013,84(4):472-477

In the present study, we investigated the effect of a long-term mountain expedition on glucose tolerance and insulin action. Twelve registered mountaineers ages 31 years (SD = 1.1) participated in a 25-day expedition at a 2,200-3,800-m altitude with an average duration of 8 hr per day. Arterial oxygen saturation (SaO2) was substantially reduced during hiking. Glucose tolerance and insulin responses were measured prior to and twice during the expedition period. Maximal oxygen consumption increased from 43.0 ± 2.7 to 49.1 ± 2.2 mL/kg/min. Percentage of body fat decreased from 19.4 ± 6.8% to 16.9 ± 5.9%. The area under the curves for insulin and glucose during the oral glucose tolerance test were also reduced in Days 3 and 25. The present study demonstrated that altitude hiking activity is an effective lifestyle intervention to improve insulin action.  相似文献