First-principles Calculation of the Formation Energy in MgO-CaO Solid Solutions

The electronic structure and total energy were calculated for ordered and disordered MgO-CaO solid solutions within the multiple scattering theory in real space and the local density approximation. Based on the dependence of the total energy on the unit cell volume the equilibrium lattice parameter and formation energy were determined for different solution compositions. The formation energy of the solid solutions is found to be positive that is in agreement with the experimental phase diagram, which shows a miscibility gap.Comment: 11 pages, 3 figure

First-principles study of As interstitials in GaAs: Convergence, relaxation, and formation energy

Convergence of density-functional supercell calculations for defect formation energies, charge transition levels, localized defect state properties, and defect atomic structure and relaxation is investigated using the arsenic split interstitial in GaAs as an example. Supercells containing up to 217 atoms and a variety of {\bf k}-space sampling schemes are considered. It is shown that a good description of the localized defect state dispersion and charge state transition levels requires at least a 217-atom supercell, although the defect structure and atomic relaxations can be well converged in a 65-atom cell. Formation energies are calculated for the As split interstitial, Ga vacancy, and As antisite defects in GaAs, taking into account the dependence upon chemical potential and Fermi energy. It is found that equilibrium concentrations of As interstitials will be much lower than equilibrium concentrations of As antisites in As-rich, $n$-type or semi-insulating GaAs.Comment: 10 pages, 5 figure

Troubling troubled school time:posthuman multiple temporalities

Abstract Inspired by the philosophies of Donna Haraway and Karen Barad, the aim of this paper is to stir up trouble and to double trouble time in education. We trouble how certain views of childhood shape our experience of school time and secondly, we trouble the way in which time as experienced in school, affects how adults relate to childhood. A particular relationship to and experience of time is nowadays prominently fostered and cultivated in educational institutions. We propose that ‘time’ and ‘childhood’ are intrinsically entangled concepts and logically connected, in the lived experience of educational contemporary institutions, with colonialism and capitalism. Decolonisation requires a troubling of the experience of time as it involves the subordination and denigration of children and childhood (‘mysopedy’). We do this through a genealogy (a political reading of ‘the’ present) of the concepts time, childhood and school. Inspired by Karen Barad, we adopt Kyoko Hayashi’s idea of ‘travel hopping’. Travel hopping as methodology is a transindividual commitment to undo the injustices committed to those who are (also) no longer there (as well as our ‘own’ childhood ‘selves’), without any pretense that the past can be made undone. Drawing on Barad’s queer reading of Quantum Field Theory, we produce decolonising insights by diffractively tunneling through boundaries between human and nonhuman bodies in our writing, thereby unsettling the current relationship to time, the adult/child binary and adult temporality

Demonstration of a new pathogenic mutation in human complex I deficiency: a 5-bp duplication in the nuclear gene encoding the 18-kD (AQDQ) subunit.

We report the cDNA cloning, chromosomal localization, and a mutation in the human nuclear gene encoding the 18-kD (AQDQ) subunit of the mitochondrial respiratory chain complex I. The cDNA has an open reading frame of 175 amino acids and codes for a protein with a molecular mass of 23.2 kD. Its gene was mapped to chromosome 5. A homozygous 5-bp duplication, destroying a consensus phosphorylation site, in the 18-kD cDNA was found in a complex I-deficient patient. The patient showed normal muscle morphology and a remarkably nonspecific fatal progressive phenotype without increased lactate concentrations in body fluids. The child's parents were heterozygous for the mutation. In 19 other complex I-deficient patients, no mutations were found in the 18-kD gene

Affecting the Ageing Behaviour of Injection-Moulded Microparts Using Variothermal Mould Tempering

The fast cooling of the melt in an injection moulding process for manufacturing polymer microparts can lead to a modified inner structure, resulting in minor mechanical properties. Furthermore, the ageing can be also dependent on the process-induced properties. The results indicate that especially physical ageing processes occur in parts with unpropitious inner properties. Chemical ageing processes seem to occur independently of the process conditions in microparts. Tensile tests indicate that a process-induced favoured morphology can reduce the ageing-based change of mechanical properties