Search

Though we have advocated explicit argumentation instruction in science classes for decades, daily instructions are still found insufficient in improving students' argumentation competence. It is therefore important to explore effective instructional strategies through classroom research. This paper compares instructional strategies for classroom argumentation. We report on a quasi-experiment conducted with tenth-grade students (n = 92) that compares "adversarial" and "parallel" argumentation designs for the topic "genetic inheritance," an inquiry-based socio-scientific issue (SSI) unit. The instruction was conducted through the online platform, Web-based Inquiry Science Environment (WISE). In the "parallel" design, student dyads were assigned to the same initial stances and were asked to change to multiple perspectives together, while in the "adversarial" design, students were assigned to opposite stances, and a debate was launched between the two sides. Students' overall argumentation performance improved significantly in both cases, yet the progress was greater in terms of "counterarguments" for students in the "parallel" design. Such findings highlight the value of "parallel" thinking in developing students' argumentation competence, especially in producing "counterarguments." Suggestions on instructional design for scientific argumentation activities are proposed accordingly.

Simultaneous localization and map building of mobile robots is an important research direction in robotics, and multi-sensor fusion is one of the key technologies for mobile robots to achieve autonomous navigation. In this paper, firstly, based on the framework of the SLAM system, we analyze the extraction of FAST feature points and BRIEF feature descriptor matching and propose the CSD-ORB algorithm. Secondly, the FKCS-LD algorithm based on the fusion map key frame and center selection strategy is proposed. The suitable multi-sensor fusion SLAM system is selected to build the back-end optimization algorithm based on the bit-pose map. Finally, we complete the comparison experiments of the multi-sensor fusion SLAM system on standard data sets, robot hardware assembly and software environment construction, and actual field testing. The experimental data show that the trajectory calculation accuracy can be further improved by using local map tracking, i.e., the current frame and local keyframe to calculate the bit pose, in which the maximum error is 6 cm, the root mean square error is reduced to 3.6 cm, the maximum value of local optimization is 0.66034, the minimum value is 0.146232, the average is 0.32812, and the median is 0.33023. The experiment proves that the multi-sensor fusion SLAM system can achieve centimeter-level accuracy and has global consistency and real-time performance, and can effectively complete the task of simultaneous robot positioning and map building.

An increasing number of studies in science education have proved the positive effects of students' epistemic beliefs on their academic achievements and self-efficacy. Despite the critical roles of teachers' classroom talks on shaping students' epistemic beliefs, little research has explored teachers' talks from epistemic perspectives. Therefore, this study undertook an epistemic analysis of two high school science teachers' class talks in China. The findings show the teachers' talks were focused on 'constructing knowledge' practices, with very few of 'explanation' operation. In the observed classes, teachers led most 'description' and 'argument' operations, while the students were involved in a low level of epistemic load. The epistemic features of teachers' talks were influenced by both exam pressures and teachers' pedagogical beliefs. This study argues that the latter was undermined by exam pressures in education systems and was neglected in the current teacher education system. This study indicates the context-dependent nature of teachers' epistemic talks in science classes and advocates the explicit teaching of epistemic cognition in teacher education courses.

In response to the 2001 National curriculum review in China, which explicitly promotes scientific inquiry in science-related subjects, many editions of new textbooks were published. Among them, this study explored the quality of scientific inquiry in the most popular science textbooks. There are nine sets of high school science textbooks published by seven major Chinese publishers in this study. Through the content analysis of these textbooks, it is found that all the textbooks included the specific sections dedicated to scientific inquiry. The quality of scientific inquiry in these textbooks was explored on specific aspects including relevance to daily life, the explicit teaching guidance, the complete inquiry process and the openness of inquiry. The findings suggest that 53% of inquiry activities included close connections to daily life. However, there were very few textbooks providing explicit teaching guidance. In particular, regarding the inquiry process of "results implications" and "making new inquiries", 4% and 9% of inquiry activities in the textbooks came with explicit teaching guidance. Moreover, most of the activities lacked the process of scientific inquiry, especially at the stage of "questioning". The findings are also in accordance with other literature that states that most textbooks lack high-level, open-ended inquiries. This study suggests that science textbooks should include more relevant scientific inquiries with explicit teaching guidance, opportunities for students to experience the complete inquiry process and more student autonomy in conducting inquiry.

Myelodysplastic syndromes (MDS) are heterogeneous hematopoietic disorders that are incurable with conventional therapy. Their incidence is increasing with global population aging. Although many genetic, epigenetic, splicing, and metabolic aberrations have been identified in patients with MDS, their clinical features are quite similar. Here, we show that hypoxia-independent activation of hypoxia-inducible factor 1α (HIF1A) signaling is both necessary and sufficient to induce dysplastic and cytopenic MDS phenotypes. The HIF1A transcriptional signature is generally activated in MDS patient bone marrow stem/progenitors. Major MDS-associated mutations (Dnmt3a, Tet2, Asxl1, Runx1, and Mll1) activate the HIF1A signature. Although inducible activation of HIF1A signaling in hematopoietic cells is sufficient to induce MDS phenotypes, both genetic and chemical inhibition of HIF1A signaling rescues MDS phenotypes in a mouse model of MDS. These findings reveal HIF1A as a central pathobiologic mediator of MDS and as an effective therapeutic target for a broad spectrum of patients with MDS.Significance: We showed that dysregulation of HIF1A signaling could generate the clinically relevant diversity of MDS phenotypes by functioning as a signaling funnel for MDS driver mutations. This could resolve the disconnection between genotypes and phenotypes and provide a new clue as to how a variety of driver mutations cause common MDS phenotypes. Cancer Discov; 8(11); 1438-57. ©2018 AACR. See related commentary by Chen and Steidl, p. 1355 This article is highlighted in the In This Issue feature, p. 1333.