This theoretical article problematizes the access to disciplinary knowledge that different physics representations have the possibility to provide; that is, their disciplinary affordances. It is argued that historically such access has become increasingly constrained for students as physics representations have been rationalized over time. Thus, the case is made that such rationalized representations, while powerful for communication from a disciplinary point of view, manifest as learning challenges for students. The proposal is illustrated using a vignette from a student discussion in the physics laboratory about circuit connections for an experimental investigation of the charging and discharging of a capacitor. It is concluded that in order for students to come to appreciate the disciplinary affordances of representations, more attention needs to be paid to their "unpacking." Building on this conclusion, two questions are proposed that teachers can ask themselves in order to begin to unpack the representations that they use in their teaching. The paper ends by proposing directions for future research in this area.

The purpose of this investigation was to examine, from a cross-cultural perspective, students' epistemological patterns of reasoning about socioscientific issues (SSI), and to identify potential interactions of cultural and scientific identity. Mediating factors associated with students' argumentation and discourse about SSI, as well as the public's understanding of science, has been identified as an important area of investigation in the field of science education. This mixed-methods design included over 300 students from Jamaica, South Africa, Sweden, Taiwan, and the United States. Students responded to instruments designed to assess their epistemological conceptualizations and justifications related to distributive justice, allocation of scarce medical resources, and epistemological beliefs over five dimensions related to scientific knowledge. Four iterations of a coding scheme produced over 97% inter-rater agreement for four independent coders. Results indicate there is a consistent trend toward epistemological congruity across cultures within inductively derived themes of: (1) Fairness;(2) Pragmatism; (3) Emotive Reasoning; (4) Utility; and (5) Theological Issues. Moreover, there were no discernable differences in terms of how students from these countries presented their beliefs on the sub-categories of each of the five major categories. It appears that students displayed a high degree of congruence with respect to how they frame their reasoning on this SSI as well as their justifications for their epistemological beliefs. There were statistically significant differences regarding the ability to raise scientifically relevant questions among countries. Commonalities as well as distinguishing characteristics in epistemological orientations are compared and contrasted and connections to a model of socioscientific reasoning with implications for research and pedagogy are discussed. ß 2013 Wiley Periodicals, Inc. J Res Sci Teach 50: 2013 The purpose of this investigation was to examine, from a cross-cultural perspective, students' epistemological patterns of reasoning about socioscientific issues (SSI), and to identify potential interactions of cultural and scientific identity. We derive our fundamental meaning of epistemological beliefs from the Greek term epistēmē, which expresses how individuals construe and justify meaning from their own personal knowledge and understanding about the world. In this context, epistemological reasoning refers to how individuals frame an issue and Additional Supporting Information may be found in the online version of this article.

Recently, the South African Institute of Physics undertook a major review of university physics education. The report highlighted the necessity for further transformation of the teaching of physics, particularly in relation to the teaching of under-prepared students.In this article we examine how physics lecturers in South Africa reported how they respond to the teaching challenges that they face in terms of representational competence. We argue that the goal of any undergraduate degree is the production of disciplinary literate graduates, where disciplinary literacy refers to the ability to competently deal with the various representational formats used within the discipline. For physics the development of disciplinary literacy involves competence in a wide range of representations, such as; written and oral languages, diagrams, graphs, mathematics, apparatus, simulations, etc.Our interest in this study was the way in which individual physics lecturers described how they deal with their students' lack of representational competence. To this end, we interviewed 20 physics lecturers from five purposefully selected representative South African universities about their students' lack of representational competence and the educational strategies they use for dealing with this problem. These interviews were transcribed verbatim and analysed for potential patterns.Iterative, interpretive analysis resulted in the identification of six qualitatively different response strategies that South African physics lecturers indicate they invoke to deal with their students' lack of representational competence. We suggest that an understanding of this range of possible response strategies will allow physics lecturers to better understand their own responses and those of their peers, and that this, in turn, may lead to changes in educational practice.Based on the differences in individual response strategies that we find, we further argue that inter-and intra-faculty discussions about undergraduate disciplinary literacy goals have the distinct potential for reforming South African undergraduate physics. Here, we suggest that the disciplinary literacy discussion matrix that we used to initiate dialogue in our interviews may also double as a useful starting point for such faculty discussions.

The multiplication rate of blue-tongue virus in suckling and adult mouse brains has been determined. The first cycle of virus multiplication appears to take 8–12 hr. both in fully susceptible sucklings and in adults which suffer an inapparent infection with this virus.Antigens suitable for complement-fixation tests have been made from suckling mouse brains and from eggs infected with blue-tongue virus.A potent immune serum has been obtained from mice immunized by repeated intraperitoneal injections of blue-tongue virus in suckling mouse brain.Attempts, with negative results, have been made to demonstrate interference with virus multiplication by virus from eggs incubated at 38·5° C. and by virus from adult mouse brains.We are grateful to Dr R. Alexander for his helpful and critical interest in this work and to Mr G. S. Turner and Dr G. Selzer for their able and willing assistance.The Virus Research Unit is financed by the South African Council for Scientific and Industrial Research and by grants from the Nkana-Kitwe and Chingola Poliomyelitis Research Funds.

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