Domain Bundle Boundaries in Single Crystal BaTiO3 Lamellae: Searching for Naturally Forming Dipole Flux-Closure / Quadrupole Chains

Naturally occurring boundaries between bundles of 90o stripe domains, which form in BaTiO3 lamellae on cooling through the Curie Temperature, have been characterised using both piezoresponse force microscopy (PFM) and scanning transmission electron microscopy (STEM). Detailed interpretation of the dipole configurations present at these boundaries (using data taken from PFM) shows that, in the vast majority of cases, they are composed of simple zigzag 180° domain walls. Topological information from STEM shows that, occasionally, domain bundle boundaries can support chains of dipole flux closure and quadrupole nanostructures, but these kinds of boundaries are comparatively rare; when such chains do exist, it is notable that singularities at the cores of the dipole structures are avoided. The symmetry of the boundary shows that diads and centres of inversion exist at positions where core singularities should have been expected.

Using survey data to explore preschool children’s ethnic awareness and attitudes

This article presents the findings of a large-scale survey (n = 1049) of ethnic awareness and attitudes among three to four-year-old children in Northern Ireland. In drawing upon and applying Bourdieu’s notion of habitus, the article demonstrates how, even at this age, the children are already beginning to embody and internalize the cultural habits and dispositions of their respective ethnic groups; namely the Protestant and Catholic communities. This is illustrated in the present article in relation to the children’s attitudes towards particular national flags and awareness of specific sports associated with their respective communities. Informed by the work of Bourdieu, the article concludes by arguing for the need for greater use of quantitative methods in conjunction with in-depth qualitative and ethnographic research to help further our understanding of the influence of ethnicity in young children’s lives.

Modeling Frequency-Dependent Boundaries as Digital Impedance Filters in FDTD and K-DWM Room Acoustics Simulations

A new method for modeling-frequency-dependent boundaries in finite-difference time-domain (FDTD) and Kirchhoff variable digital waveguide mesh (K-DWM) room acoustics simulations is presented. The proposed approach allows the direct incorporation of a digital impedance filter (DIF) in the Multidimensional (2D or 3D) FDTD boundary model of a locally reacting surface. An explicit boundary update equation is obtained by carefully constructing a Suitable recursive formulation. The method is analyzed in terms of pressure wave reflectance for different wall impedance filters and angles of incidence. Results obtained from numerical experiments confirm the high accuracy of the proposed digital impedance filter boundary model, the reflectance of which matches locally reacting surface (LRS) theory closely. Furthermore a numerical boundary analysis (NBA) formula is provided as a technique for an analytic evaluation of the numerical reflectance of the proposed digital impedance filter boundary formulation.

Dilemmatic human-animal boundaries in Britain and Romania: Post-materialist and materialist dehumanization

Theories of dehumanization generally assume a single clear-cut, value-free and non-dilemmatic boundary between the categories 'human' and 'animal'. The present study highlights the relevance of dilemmas involved in drawing that boundary. In six focus groups carried out in Romania and Britain, 42 participants were challenged to think about dilemmas pertaining to animal and human life. Four themes were identified: rational autonomy, sentience, speciesism and maintaining materialist and post-materialist values. Sentience made animals resemble humans, while humans' rational autonomy made them distinctive. Speciesism underlay the human participants' prioritization of their own interests over those of animals, and a conservative consensus that the existing social system could not change supported this speciesism when it was challenged. Romanian participants appealed to Romania's lack of modernity and British participants to Britain's modernity to justify such conservatism. The findings suggest that the human-animal boundary is not essentialized; rather it seems that such boundary is constructed in a dilemmatic and post hoc way. Implications for theories of dehumanization are discussed.

Who We Are and Who Can Join Us: National Identity Content and Entry Criteria for New Immigrants

We argue that attitudes about immigration can be better understood by paying closer attention to the various ways in which national group boundaries are demarcated. We describe two related lines of work that address this. The first deals with national group definitions and, based on evidence from studies carried out in England and analyses of international survey data, argues that the relationship between national identification and prejudice toward immigrants is contingent on the extent to which ethnic or civic definitions of nationality are endorsed. The second, which uses European survey data, examines support for ascribed and acquired criteria that can be applied when determining who is permitted to migrate to one's country, and the various forms of national and individual threat that affect support for these criteria. We explain how the research benefits from a multilevel approach and also suggest how these findings relate to some current policy debates.