Decay and fusion as two different mechanisms of stability loss for the (C_20)_2 cluster dimer

The thermal stability of the (C_20)_2 cluster dimer consisting of two C_20 fullerenes is examined using a tight-binding approach. Molecular dynamics simulations of the (C_20)_2 dimer at temperatures T = 2000 - 3500 K show that the finite lifetime \tau of this metastable system is determined by two fundamentally different processes, the decay of one of the C_20 fullerenes and the fusion of two C_20 fullerenes into the C_40 cluster. The activation energies for these processes Ea = 3.4 and 2.7 eV, respectively, as well as their frequency factors, have been determined by analyzing the dependence of \tau on T.Comment: Slightly modified version of the paper to appear in JETP Let

Metabolic engineering of Rhizopus oryzae for the production of platform chemicals

Rhizopus oryzae is a filamentous fungus belonging to the Zygomycetes. It is among others known for its ability to produce the sustainable platform chemicals l-(+)-lactic acid, fumaric acid, and ethanol. During glycolysis, all fermentable carbon sources are metabolized to pyruvate and subsequently distributed over the pathways leading to the formation of these products. These platform chemicals are produced in high yields on a wide range of carbon sources. The yields are in excess of 85 % of the theoretical yield for l-(+)-lactic acid and ethanol and over 65 % for fumaric acid. The study and optimization of the metabolic pathways involved in the production of these compounds requires well-developed metabolic engineering tools and knowledge of the genetic makeup of this organism. This review focuses on the current metabolic engineering techniques available for R. oryzae and their application on the metabolic pathways of the main fermentation products

Pedagogical memory and the space of the postcolonial classroom : reading Dangarembga's Nervous Conditions

This article addresses issues of the mnemonic space of the literature classroom by interrogating a classic text of African women’s writing, Tsitsi Dangaremnga’s Nervous Conditions (1988) for the ways it speaks about education in 1960s and 1970s late-colonial Rhodesia. The article suggests that the novel reviews and critiques a number of memorial strategies that were crucial to the colonial educational system, thereby facilitating a reflexive application of the novel’s concerns to the contexts in which it is often taught, that of today’s postcolonial classrooms. The article seeks to place Dangarembga’s novel in the context of its present moment, contemporary South Africa – that of the present critic’s site of practice, both pedagogical and scholarly, and that of many of this article’s readers. This present moment, in turn, is made up the many sites, successive and simultaneous, in which the novel’s work of memory is being re-activated in the minds of students as readers and writers. Via a dialogue between the textual past and the pedagogical present, one which is often subject to critical amnesia, the article seeks to inaugurate a debate on the nature of pedagogical memory in the space of the postcolonial university or high school literature classroom.http://www.informaworld.com/RSCRhb2013gv201

Butterfly nomenclature: a critique

Volume: 20Start Page: 1End Page: 1

Classroom Interaction

A social interaction perspective on classroom interaction studies the mechanisms teachers and students use to conduct their classroom business. This article on classroom interaction first discusses the ways teachers and students have organized turn‐taking and the ways they use their turns at talk to engage in classroom activities. One particularly important format for these activities is the action sequences of teacher initiation, student response, and teacher evaluation of that response (the IRE sequence). Next it addresses two strands of classroom interaction research that particularly aim to relate classroom practices to larger societal issues such as modes of production (critical research) and ethnic and linguistic diversity (diversity research). Finally, the article contains a detailed discussion of recent research of learning in interaction