Origin of charge density at LaAlO3-on-SrTiO3 hetero-interfaces; possibility of intrinsic doping

As discovered by Ohtomo et al., a large sheet charge density with high mobility exists at the interface between SrTiO3 and LaAlO3. Based on transport, spectroscopic and oxygen-annealing experiments, we conclude that extrinsic defects in the form of oxygen vacancies introduced by the pulsed laser deposition process used by all researchers to date to make these samples is the source of the large carrier densities. Annealing experiments show a limiting carrier density. We also present a model that explains the high mobility based on carrier redistribution due to an increased dielectric constant.Comment: 14 pages, 3 figures, 1 table; accepted for publication in Phys. Rev. Lett

Self-efficacy enhanced in a cross-cultural context through an initiative in under-resourced schools in KwaZulu-Natal, South Africa

This paper discusses the Khanyisa Programme, an initiative in KwaZulu-Natal, South Africa, where learners from under-resourced schools are supported by teachers and high achievers in Grade 11 and 12 from a previously advantaged state school under apartheid. A qualitative, evaluative study was undertaken to identify key elements in the ongoing success of the programme and collect participant suggestions for improvement. The findings, discussed within the framework of self-efficacy theory, identified enormous gains by Khanyisa learners, leading to vastly improved career prospects

Microbial differences between dental plaque and historic dental calculus are related to oral biofilm maturation stage

Dental calculus, calcified oral plaque biofilm, contains microbial and host biomolecules that can be used to study historic microbiome communities and host responses. Dental calculus does not typically accumulate as much today as historically, and clinical oral microbiome research studies focus primarily on living dental plaque biofilm. However, plaque and calculus reflect different conditions of the oral biofilm, and the differences in microbial characteristics between the sample types have not yet been systematically explored. Here, we compare the microbial profiles of modern dental plaque, modern dental calculus, and historic dental calculus to establish expected differences between these substrates.- Background - Results -- Authentication of a preserved oral biofilm in calculus samples -- Dental calculus and plaque biofilm communities are distinct -- Health-associated communities of dental plaque and calculus are distinct -- Signatures of health and of disease are shared in modern and historic calculus samples -- Microbial community differences between health and disease in calculus are poorly resolved -- Absence of caries-specific microbial profiles in dental calculus -- Microbial co-exclusion patterns in plaque and calculus reflect biofilm maturity -- Microbial complexes in plaque and calculus -- Functional prediction in calculus is poorly predictive of health status -- Proteomic profiles of historic healthy site calculus -- Correlations between taxonomic, proteomic, and metabolomic profiles - Discussion - Conclusions - Materials and methods --Historic and modern calculus sample collection DNA extraction -- DNA library construction and high-throughput sequencing -- DNA sequence processing -- Genetic assessment of historic calculus sample preservation -- Genetic microbial taxonomic profiling -- Principal component analysis -- Assessment of differentially abundant taxa -- Sparse partial least squares-discriminant analysis -- Assessment of microbial co-exclusion patterns -- Gene functional categorization with SEED -- Proteomics -- Metabolomics -- Regularized canonical correlation analysi

Mobility as a contradictory resource: Peripatetic Qur’anic students in Kano, Nigeria

Mobility is a powerful resource young people can draw on to improve their lives, but it can also entail risks. This paper explores how mobility becomes a contradictory resource for peripatetic Qur'anic students (almajirai) in Kano State in northern Nigeria. Moving to urban areas allows the young almajirai to escape difficult conditions and to access educational and income opportunities absent in their rural homes. It makes it possible for them to adopt self-conceptions as migrants in search of sacred knowledge who were once widely respected. However, economic decline has made survival in the city more difficult. Lacking the economic and cultural resources to participate in displays of status, and without social superiors to speak for them, the almajirai feel they have become fair game for those searching for scapegoats

The Arts in Basic Curriculum Project : Looking at the Past and Preparing for the Future

The primary findings of this evaluation are (1) that the ABC Project has built and supported a strong network that measurably strengthens arts education, and (2) for the reform to continue, there must be new initiatives. The Project has made a significant first step toward providing quality opportunities for all children in South Carolina, but the gap between the current state of arts education and the stated goal of the Project is very wide. Therefore, these new initiatives must be bold, innovative, strongly funded, and backed with the energies and passions of those in the core arts education network. The basic recommendation that subsumes all the specific recommendations in this report is to develop a data-informed strategic plan for arts education, then determine funding priorities based on this plan