Scaffolding group explanation and feedback with handheld technology: impact on students’ mathematics learning

Based on strong research literatures, we conjectured that social processing of feedback by cooperating in a small group setting—with social incentives to ask questions, give explanations and discuss disagreements—would increase learning. We compared group and individual feedback, using two technologies: (1) Technology-mediated, Peer-Assisted Learning (TechPALS), which uses wireless handheld technology to structure feedback in small groups as they solve fractions problems and (2) a popular desktop product, which provides feedback to individual students as they solve fractions problems individually. Three elementary schools participated in a randomized controlled experiment conducted in the 2007–2008 school year. Students in the TechPALS condition learned more than did the control group students, with effect sizes ranging from d = 0.14 to d = 0.44. Analysis of observational data confirmed that students in the TechPALS condition participated socially in questioning, explaining, and discussing disagreements, whereas students in the individual condition did not. We conclude that an integration of technology, cooperative activity designs and broader educational practices can lead to impact on students’ mathematics learning.     

苹果与谷歌的竞争日趋个人化

3年前,谷歌首席执行官埃里克·施密特与苹果创始人之一史蒂芬·乔布斯携手合作,并帮助后者开发出了具有划时代意义的产品——iPhoneo那似乎是一段美好友谊的开始。     

Multinationality, foreignness and institutional distance in the relation between R&D and productivity

This paper empirically examines to what extent being foreign and part of a multinational affects the endogenous relation between R&D and productivity. Our findings indicate that multinationals obtain in general higher R&D returns. Also, there is a negative foreignness effect in that domestic-owned multinationals outperform foreign subsidiaries. However, these effects are somehow moderated by the institutional distance between the home and host countries. These results, obtained for a panel of UK firms, are largely consistent with a set of hypotheses derived from the institutional and international business theories.     

ApoStream?, a new dielectrophoretic device for antibody independent isolation and recovery of viable cancer cells from blood

Isolation and enumeration of circulating tumor cells (CTCs) are used to monitor metastatic disease progression and guide cancer therapy. However, currently available technologies are limited to cells expressing specific cell surface markers, such as epithelial cell adhesion molecule (EpCAM) or have limited specificity because they are based on cell size alone. We developed a device, ApoStream^™ that overcomes these limitations by exploiting differences in the biophysical characteristics between cancer cells and normal, healthy blood cells to capture CTCs using dielectrophoretic technology in a microfluidic flow chamber. Further, the system overcomes throughput limitations by operating in continuous mode for efficient isolation and enrichment of CTCs from blood. The performance of the device was optimized using a design of experiment approach for key operating parameters such as frequency, voltage and flow rates, and buffer formulations. Cell spiking studies were conducted using SKOV3 or MDA-MB-231 cell lines that have a high and low expression level of EpCAM, respectively, to demonstrate linearity and precision of recovery independent of EpCAM receptor levels. The average recovery of SKOV3 and MDA-MB-231 cancer cells spiked into approximately 12 × 10⁶ peripheral blood mononuclear cells obtained from 7.5 ml normal human donor blood was 75.4% ± 3.1% (n = 12) and 71.2% ± 1.6% (n = 6), respectively. The intra-day and inter-day precision coefficients of variation of the device were both less than 3%. Linear regression analysis yielded a correlation coefficient (R²) of more than 0.99 for a spiking range of 4–2600 cells. The viability of MDA-MB-231 cancer cells captured with ApoStream was greater than 97.1% and there was no difference in cell growth up to 7 days in culture compared to controls. The ApoStream device demonstrated high precision and linearity of recovery of viable cancer cells independent of their EpCAM expression level. Isolation and enrichment of viable cancer cells from ApoStream enables molecular characterization of CTCs from a wide range of cancer types.     

The Contribution of Ethnobiology to the Construction of a Dialogue Between Ways of Knowing: A Case Study in a Brazilian Public High School

This paper reports results obtained in pedagogical interventions in a Brazilian public high school which aimed at promoting a dialogue between scientific and traditional knowledge in the context of biology teaching. The interventions were based on the use of a didactic material and teaching sequence elaborated on the grounds of school knowledge about botany, as presented in biology textbooks, and interviews with students who were also farmers, so as to gather data about their ethnobiological knowledge. Our goal was to develop and test resources that can offer support for teachers who wish to build a dialogue between different ways of knowing in multicultural settings. Our results indicate that the use of the didactic material and teaching sequence indeed created possibilities for a dialogue between the students’ ethnobiological knowledge and biology school knowledge. We observed some shortcomings in classroom practice, partly reflecting our very choice of subject matter to develop the teaching sequence. But the interventions also revealed important limitations that we regard as representative of problems that may generally make multicultural science teaching a hard goal to achieve. It was clear that important shortcomings were related to teachers’ difficulties to conduct a dialogue between ways of knowing in a science classroom, and, thus, called attention to the importance of introducing a multicultural dimension into teacher education. We also observed that the fact that students did not show much sensitivity towards dealing with cultural diversity was a factor constraining the success of the interventions. These results highlight the importance of proposing and testing teacher education initiatives aiming at preparing them to teach science in a culturally sensitive manner, and also managing classroom tensions and conflicts so as to make it possible an effective dialogue between different ways of knowing in a multicultural setting.     

Contribution of historical Spanish inventions to the knowledge of olive oil industrial heritage

This article presents new research, which has the objective of quantifying the knowledge produced by historical technological innovations in the field of olive oil industrial heritage. It studies inventions related to the mechanical processes of the extraction of olive oil between 1826 and 1966, which are recorded in the Historical Archive of the Spanish Patent and Trademark Office. It uses a new adaptation of the methodology of knowledge management (KM) defined by Nonaka and Takeuchi. We have obtained the knowledge value of each innovation according to the level of technological knowledge registered at the time, while distinguishing between the historical evolution of inventions relating to milling and those relating to pressing. In the first analysis, the results show a recession in the quantitative level of knowledge in the olive oil sector with respect to the technological potential of the time. However, when contrasted with the events relating to industrial heritage at the time, it is possible to account for this technological evolution and prove the validity of the methodology used. The results show that general evolution of the knowledge generated has decreased, particularly in the pressing process, although this is not the case in the milling process.     

Coordinating learning analytics policymaking and implementation at scale

Many Latin-American institutions recognise the potential of learning analytics (LA). However, the number of actual LA implementations at scale remains limited, notwithstanding considerable effort made to formulate guidelines and frameworks to support the LA policy development. Guidance on how to coordinate the interaction between the LA policymaking and implementation is mostly missing, leaving a difficult challenge up to practitioners. In this study we propose a coordination model to support future LA initiatives at scale. We explore the problem by comparing two cases in Belgium and Ecuador. Following up we use the LA implementation timeline as a driver for planning the interaction between the policymaking and implementation. We continue by testing an application of the model with LA experts predominantly from Latin-American institutions, asking them to map low-level items of the SHEILA policy framework to four implementation phases. The results of this mapping support that LA policy building can be spread over time, that it can coincide with LA implementation at scale, and that both efforts can be coordinated. It is hoped that this study will provide additional guidance for future Latin-American and other LA initiatives.     

Relationships between everyday knowledge and scientific knowledge: understanding how matter changes

This paper analyses the representations held by adolescents and university students in relation to the mechanism for explaining changes in matter (changes of state, dissolutions, expansions and chemical reactions) in terms of the kinetic theory. The answers to a questionnaire were analysed by considering the proportion of correct answers and the use of alternative conceptions. The results show that understanding of explanatory mechanisms of changes in matter is affected by age and instruction level and content of the problem. The main conception that competes with the kinetic model is the attribution to the particles of the changes observed, at a macroscopic level. This is more evident in changes of state and expansions than in other changes. This confusion results from a failure to differentiate properly between the represented reality and the model that represents it. In conclusion, analysis has shown once more students' difficulties in going beyond apparent reality or integrating the data obtained from it into the scientific models they learn at school.