The Unification of Asymmetry Signatures of Type Ia Supernovae

We present a compilation of the geometry measures acquired using optical and IR spectroscopy and optical spectropolarimetry to probe the explosion geometry of Type Ia supernovae (SNe Ia). Polarization measurements are sensitive to asymmetries in the plane of the sky, whereas line profiles in nebular phase spectra are expected to trace asymmetries perpendicular to the plane of the sky. The combination of these two measures can overcome their respective projection effects, completely probing the structures of these events. For nine normal SNe Ia, we find that the polarization of Si II ?6355 at 5 days before maximum (p Si II ) is well correlated with its velocity evolution (\dot{v}_Si II), implying that \dot{v}_Si II is predominantly due to the asymmetry of the SNe. We find only a weak correlation between the polarization of Si II and the reported velocities (v neb) for peak emission of optical Fe II and Ni II lines in nebular spectra. Our sample is biased, with polarization measurements being only available for normal SNe that subsequently exhibited positive (i.e., redshifted) v neb. In unison these indicators are consistent with an explosion in which the outer layers are dominated by a spherical oxygen layer, mixed with an asymmetric distribution of intermediate-mass elements. The combination of spectroscopic and spectropolarimetric indicators suggests a single geometric configuration for normal SNe Ia, with some of the diversity of observed properties arising from orientation effects.

Present orientation, future orientation and alcohol use in Northern Irish adolescents

Earlier initiation into more problematic drinking behaviour has been found to be associated with more problematic drinking later in life. Research has suggested that a lower future time perspective (and higher present time perspective) is associated with health-compromising behaviours such as problematic alcohol use in college student, University undergraduate and general population samples. This study used a cross-sectional design to examine whether consideration of future consequences (CFC), assessed by the Consideration of Future Consequences Scale, was significantly related to drinking behaviour in a large sample (n=707) of Northern Irish adolescents. Alcohol use was self-reported by means of a composite measure of drinking behaviour. Demographic data were also gathered. After controlling for year in school (proxy for age), sex and for clustering at school level, lower future orientation and higher present orientation were found to be significantly associated with more problematic self-reported drinking behaviour. These results extend recent findings of a significant relationship between a foreshortened future time perspective and more problematic self-reported drinking behaviour in a UK sample of University undergraduates, to a large UK sample of adolescents. Given the relationship between early-onset drinking and more problematic use in later life, health promotion interventions might explore using the CFC construct in targeting adolescent drinkers.

A correction to the analytical solution of the mixed-mode bending (MMB) problem

This paper addresses the analytical solution of the mixed-mode bending (MMB) problem. The first published solutions used a load separation in pure mode I and mode II and were applied for a crack length less than the beam half-span, a <= L. In later publications, the same mode separation was used in deriving the analytical solution for crack lengths bigger than the beam half-span, a > L. In this paper it is shown that this mode separation is not valid when a > L and in some cases may lead to very erroneous results. The correct mode separation and the corresponding analytical solutions, when a > L, are presented. Results, of force vs. displacement and force vs. crack length graphs, obtained using the existing formulation and the corrected formulation are compared. A finite element solution, which does not use mode separation, is also presented

Understanding the migratory orientation program of birds: extending laboratory studies to study free flying migrants in a natural setting

For many years, orientation in migratory birds has primarily been studied in the laboratory. Although a laboratory-based setting enables greater control over environmental cues, the laboratory-based findings must be confirmed in the wild in free-flying birds to be able to fully understand how birds orient during migration. Despite the difficulties associated with following free-flying birds over long distances, a number of possibilities currently exist for tracking the long distance, sometimes even globe-spanning, journeys undertaken by migrating birds. Birds fitted with radio transmitters can either be located from the ground or from aircraft (conventional tracking), or from space. Alternatively, positional information obtained by onboard equipment (e.g., GPS units) can be transmitted to receivers in space. Use of these tracking methods has provided a wealth of information on migratory behaviors that are otherwise very difficult to study. Here, we focus on the progress in understanding certain components of the migration-orientation system. Comparably exciting results can be expected in the future from tracking free-flying migrants in the wild. Use of orientation cues has been studied in migrating raptors (satellite telemetry) and thrushes (conventional telemetry), highlighting that findings in the natural setting may not always be as expected on the basis of cage-experiments. Furthermore, field tracking methods combined with experimental approaches have finally allowed for an extension of the paradigmatic displacement experiments performed by Perdeck in 1958 on the short-distance, social migrant, the starling, to long-distance migrating storks and long-distance, non-socially migrating passerines. Results from these studies provide fundamental insights into the nature of the migratory orientation system that enables experienced birds to navigate and guide inexperienced, young birds to their species-specific winter grounds.

A strategy to identify critical appraisal criteria for primary mixed-method studies

The practice of mixed-methods research has increased considerably over the last 10 years. While these studies have been criticized for violating quantitative and qualitative paradigmatic assumptions, the methodological quality of mixed-method studies has not been addressed. The purpose of this paper is to identify criteria to critically appraise the quality of mixed-method studies in the health literature. Criteria for critically appraising quantitative and qualitative studies were generated from a review of the literature. These criteria were organized according to a cross-paradigm framework. We recommend that these criteria be applied to a sample of mixed-method studies which are judged to be exemplary. With the consultation of critical appraisal experts and experienced qualitative, quantitative, and mixed-method researchers, further efforts are required to revise and prioritize the criteria according to importance.

Revisiting the quantitative-qualitative debate:Implications for mixed-methods research

Health care research includes many studies that combine quantitative and qualitative methods. In this paper, we revisit the quantitative-qualitative debate and review the arguments for and against using mixed-methods. In addition, we discuss the implications stemming from our view, that the paradigms upon which the methods are based have a different view of reality and therefore a different view of the phenomenon under study. Because the two paradigms do not study the same phenomena, quantitative and qualitative methods cannot be combined for cross-validation or triangulation purposes. However, they can be combined for complementary purposes. Future standards for mixed-methods research should clearly reflect this recommendation.

Nanoscale Control of Phase Variants in Strain-Engineered BiFeO3

Development of magnetoelectric, electromechanical, and photovoltaic devices based on mixed-phase rhombohedral-tetragonal (R-T) BiFeO3 (BFO) systems is possible only if the control of the engineered R phase variants is realized. Accordingly, we explore the mechanism of a bias induced phase transformation in this system. Single point spectroscopy demonstrates that the T -> R transition is activated at lower voltages compared to T -> - T polarization switching. With phase field modeling, the transition is shown to be electrically driven. We further demonstrate that symmetry of formed R-phase rosettes can be broken by a proximal probe motion, allowing controlled creation of R variants with defined orientation. This approach opens a pathway to designing next-generation magnetoelectronic and data storage devices in the nanoscale.

Community identity as resource and context: A mixed method investigation of coping and collective action in a disadvantaged community

Community identities enhance well-being through the provision of social support and feelings of collective efficacy as well as by acting as a basis for collective action and social change. However, the precise mechanisms through which community identity acts to enhance well-being are complicated by stigmatisation which potentially undermines solidarity and collective action. The present research examines a real-world stigmatised community group in order to investigate: (1) the community identity factors that act to enhance well-being, and (2) the consequences of community identity for community action. Study 1 consisted of a household survey conducted in disadvantaged areas of Limerick city in Ireland. Participants (n=322) completed measures of community identification, social support, collective efficacy, community action, and psychological well-being. Mediation analysis indicated that perceptions of collective efficacy mediated the relationship between identification and well-being. However, levels of self-reported community action were low and unrelated to community identification. In Study 2, twelve follow–up multiple-participant interviews with residents and community group workers were thematically analysed, revealing high levels of stigmatisation and opposition to identity-related collective action. These findings suggest the potential for stigma to reduce collective action through undermining solidarity and social support.

Orientation effects in copper phthalocyanine films studied by electron paramagnetic resonance spectroscopy

The metallo-phthalocyanines (MPcs) are an interesting group of organic semiconductor materials for applications such as large area solar cells due to their optoelectronic properties coupled with the possibility of easily and cheaply fabricating thin films of MPcs [1, 2]. As for organic semiconductors in general, many of the interesting properties of the MPcs such as magnetism, light absorption and charge transport, are highly anisotropic [2, 3]. To maximise the efficiency of a device based on these materials it is therefore important to study their molecular orientation in films and to assess the influence of different growth conditions and substrate treatments.
X-ray diffraction is a well established and powerful technique for studying texture (and hence molecular orientation) in crystalline materials, but it cannot provide any information about amorphous or nanocrystalline films. In electron paramagnetic resonance (EPR) spectroscopy the signal comes from the spin of unpaired electrons in the material. This technique therefore does not require the sample to be crystalline. It works for any sample with paramagnetic centres such as the MPcs where the unpaired electrons are contributed by the metal. In this paper we present a continuous-wave X-band EPR study using the anisotropy of the EPR spectrum of CuPc [4] to determine the orientation effects in different types of CuPc films. From these measurements we gain insight into the molecular arrangement of films with different spin concentrations, and apply our technique to the study of molecular orientation in photovoltaic cells.