Study of the bufadienolides of the skin secretion of green toads (Bufo viridis Laur, 1758)

The composition of the skin secretion of Bufo viridis toads, which inhabit the Kharkov region, has been studied in this work

Symmetry of single chain DNA molecules

A system of "colour" transformations of symmetry is introduced on the basis of which all possible symmetry groups of the single-chain DNA molecule taken in the form of a genetic text are derived. A strict theoretical group description of such functionally important symmetrical structures as a palindrome, complementary palindrome and direct repeat is given and their possible role in the genome discussed. © 1993

Toward a Theory of Experience

Science Education, Vol. 98, No. 1, pp. 106–126Experience is one of the most used terms in (science) education, and it is recognized as being related to learning (education). Yet what experience is and how it is related to learning and change remains untheorized. In this paper, we mainly draw on the work of J. Dewey and L. S. Vygotsky but also on M. Bakhtin and more recent advances on the topic of experience from French philosophy to contribute to a theory of this important category. Accordingly, experience is not something that belongs to or is had by individuals but rather denotes transactions in and across space and time within irreducible person-in-setting units; and it is perfused with an affect that is not (only) the result of mental constructions. An episode from an Australian physics classroom is used to exemplify what such a theory and its method-related implications have to accomplish in the analysis of concrete science lessons

Understanding the role of objects in cross-disciplinary collaboration

In this paper we make a case for the use of multiple theoretical perspectives – theory on boundary objects, epistemic objects, cultural historical activity theory and objects as infrastructure - to understand the role of objects in cross-disciplinary collaboration. A pluralist approach highlights that objects perform at least three types of work in this context: they motivate collaboration; they allow participants to work across different types of boundaries; and they constitute the fundamental infrastructure of the activity. Building on the results of an empirical study we illustrate the insights that each theoretical lens affords into practices of collaboration and develop a novel analytical framework that organizes objects according to the active work they perform. Our framework can help shed new light on the phenomenon, especially with regards the shifting status of objects and sources of conflict (and change) in collaboration. After discussing these novel insights, we outline directions for future research stemming from a pluralist approach. We conclude by noting the managerial implications of our finding

A case study analysis of a constructionist knowledge building community with activity theory

This article investigates how activity theory can help research a constructionist community. We present a constructionist activity model called CONstructionism Through ACtivity Theory (CONTACT) model and explain how it can be used to analyse the constructionist activity in knowledge building communities. We then illustrate the model through its application to analysing the Wiki-supported community associated with a computer game. Our analysis focuses mainly on two perspectives: individual and collective actions, as well as individual and collective mediations. Experiences and challenges from the analysis are reported to demonstrate how CONTACT is helpful in analysing such communities

Activity theory, complexity and sports coaching: An epistemology for a discipline

The aim of this article is two-fold. Firstly, it is to advance the case for Activity Theory (AT) as a credible and alternative lens to view and research sports coaching. Secondly, it is to position this assertion within the wider debate about the epistemology of coaching. Following a framing introduction, a more comprehensive review of the development and current conceptualisation of AT is given. Here, AT’s evolution through three distinct phases and related theorists, namely Vygotsky, Leont’ev and Engeström, is initially traced. This gives way to a more detailed explanation of AT’s principal conceptual components, including ‘object’, ‘subject’, ‘tools’ (mediating artefacts), ‘rules’, a ‘community’ and a ‘division of labour’. An example is then presented from empirical work illustrating how AT can be used as a means to research sports coaching. The penultimate section locates such thinking within coaching’s current ‘epistemological debate; arguing that the coaching ‘self’ is not an autonomous individual, but a relative part of social and cultural arrangements. Finally, a conclusion summarises the main points made, particularly in terms in presenting the grounding constructivist epistemology of AT as a potential way forward for sports coaching

Teaching Writing: a situated dynamic

publication-status: Publishedtypes: ArticleThe paper is theoretically grounded in Cultural Historical Activity Theory (CHAT) which holds that human development is founded within participation in social and cultural practices. In particular, the teaching of literacy is shaped not only by the curriculum as designated by policy makers and the institution in which it is located but also by the individuals’ understanding of what literacy and learning involves and how they act to achieve their goals. The paper explores data from a project that investigated the relationship between classroom talk and the teaching of writing in six early years classrooms. Participants’ own understandings of teaching and learning need to be taken into account by researchers and policy makers. CHAT has been used to explore the dynamic relationship between activity at societal, institutional and individual levels. It is argued that researchers and policy makers need to take account of the wider socio-cultural context in planning and evaluating curriculum development initiatives

Working with activity theory : context, technology, and information behavior

Over the last 7 years, the AIMTech Research Group in the University of Leeds has used cultural‐historical activity theory (CHAT) to inform a range of research activities in the fields of information behavior and information systems. In this article, we identify certain openings and theoretical challenges in the field of information behavior, which sparked our initial interest in CHAT: context, technology, and the link between practice and policy. We demonstrate the relevance of CHAT in studying information behavior and addressing the identified openings and argue that by providing a framework and hierarchy of activity‐action‐operation and semantic tools, CHAT is able to overcome many of the uncertainties concerning information behavior research. In particular, CHAT provides researchers a theoretical lens to account for context and activity mediation and, by doing so, can increase the significance of information behavior research to practice. In undertaking this endeavour, we have relied on literature from the fields of information science and others where CHAT is employed. We provide a detailed description of how CHAT may be applied to information behavior and account for the concepts we see as relevant to its study

Project management between will and representation

This article challenges some deep-rooted assumptions of project management. Inspired by the work of the German philosopher, Arthur Schopenhauer, it calls for looking at projects through two complementary lenses: one that accounts for cognitive and representational aspects and one that accounts for material and volitional aspects. Understanding the many ways in which these aspects transpire and interact in projects sheds new light on project organizations, as imperfect and fragile representations that chase a shifting nexus of intractable human, social, technical, and material processes. This, in turn, can bring about a new grasp of notions such as value,\ud knowledge, complexity, and risk