The exchange bias phenomenon in uncompensated interfaces: Theory and Monte Carlo simulations

We performed Monte Carlo simulations in a bilayer system composed by two thin films, one ferromagnetic (FM) and the other antiferromagnetic (AFM). Two lattice structures for the films were considered: simple cubic (sc) and a body center cubic (bcc). In both lattices structures we imposed an uncompensated interfacial spin structure, in particular we emulated a FeF2-FM system in the case of the (bcc) lattice. Our analysis focused on the incidence of the interfacial strength interactions between the films J_eb and the effect of thermal fluctuations on the bias field H_EB. We first performed Monte Carlo simulations on a microscopic model based on classical Heisenberg spin variables. To analyze the simulation results we also introduced a simplified model that assumes coherent rotation of spins located on the same layer parallel to the interface. We found that, depending on the AFM film anisotropy to exchange ratio, the bias field is either controlled by the intrinsic pinning of a domain wall parallel to the interface or by the stability of the first AFM layer (quasi domain wall) near the interface.Comment: 18 pages, 11 figure

Social comparison processes and pupil outcomes in physical education

Social comparison processes and pupil outcomes in physical educatio

Land management for increased flood resilience

Natural Flood Management (NFM) (e.g. restoring watercourses, riparian tree planting, washland and wetland creation) is a core component of flood risk management strategies in Scotland. However little is known of its potential impact on the farming and land management communities, individual farm businesses, or the socioeconomic impacts and perceptions of its potential wide-spread introduction. To support policy implementation, information is required on land managers’ willingness to implement NFM, and to be able to relate willingness to generic farm characteristics (farming systems, land use types, geographical location), different types and locations of NFM measures, and to farm economics.The main objectives of the project are to undertake:1. A large scale survey of farmers’ attitudes to NFM and to the use of potential policy instruments to promote its uptake and delivery; and2. Farm-scale economic analyses of the impact of NFM measures under different scenarios

Motivation in physical education across the primary-secondary school transition

The purpose of this study was to examine the temporal patterns of approach-avoidance achievement goals, implicit theories of ability and perceived competence in physical education across the transition from primary to secondary school. We also evaluated the predictive utility of implicit theories and perceived competence with regard to achievement goal adoption, and determined the moderating influence of gender on temporal patterns and antecedent–goal relationships. One hundred and forty pupils (mean age at start of study = 11.37 years, SD =.28) completed measures of entity and incremental beliefs, perceived competence and goals on four occasions during a 12-month period. Mastery-approach, performance-approach and perform-ance-avoidance goals, as well as entity and incremental beliefs, exhibited a linear decline over time. Mastery-avoidance goals showed no significant change. Girls exhibited a linear decline in perceived competence, whereas for boys the trajectory was curvilinear. Competence perceptions predicted initial scores, but not rate of change, on mastery-approach and both types of performance goals. Incrementa

Ecosystem services bundles:challenges and opportunities for implementation and further research

Background : the concept of ‘ecosystem services bundles’, i.e. ecosystem services that repeatedly appear together across space and/or time, has been developed and refined as part of an integrated approach to assess interactions between ecosystem services. Nevertheless, published evidence of actual use of bundles in decision-making is lacking. In the light of this gap, a review of what bundle approaches have shown and what they can bring to decision-making is timely. Method : we conducted two separate systematic reviews. The first one addressed emerging issues within what we identify as the diverse utilisation and definition of the concept of ‘bundle’ in the literature. The second one focused on papers dealing with bundles as sets of consistently associated services. Review Synthesis : the review first highlights that the confusion surrounding the term ‘bundle’ in ecosystem services literature threatens to weaken the potential for analysis of bundles to inform decision-making. Then, thanks to the review of peer-reviewed papers that detect bundles as sets of consistently associated services, we analyse the diversity of methodological choices and we detail the interactions observed between different ecosystem services across the literature. We also show that landscape features, socio-economic conditions and institutional factors are all potential drivers for the occurrence of specific bundles in a landscape. Discussion : overall, it appears that the analysis of bundles provides an opportunity to enhance policy effectiveness. Nevertheless, the methodological challenges linked to the identification and interpretation of bundles call for careful and reflective study designs. We anticipate that this review will lead to a better understanding by scientists and practitioners of the potential for bundle studies to inform decision-making

What is the state of children\u27s participation in qualitative research on health interventions?: A scoping study

BACKGROUND: Children are the focus of numerous health interventions throughout the world, yet the extent of children\u27s meaningful participation in research that informs the adaptation, implementation, and evaluation of health interventions is not known. We examine the type, extent, and meaningfulness of children\u27s participation in research in qualitative health intervention research. METHOD: A scoping study was conducted of qualitative published research with children (ages 6-11 years) carried out as part of health intervention research. Following Arksey and O\u27Malley\u27s scoping study methodology and aligned with the PRISMA-ScR guidelines on the reporting of scoping reviews, the authors searched, charted, collated, and summarized the data, and used descriptive and content analysis techniques. Ovid MEDLINE was searched from 1 January 2007 to 2 July 2018 using the keywords children, health intervention, participation, and qualitative research. Study selection and data extraction were carried out by two reviewers independently. RESULTS: Of 14,799 articles screened, 114 met inclusion criteria and were included. The study identified trends in when children were engaged in research (e.g., post-implementation rather than pre-implementation), in topical (e.g., focus on lifestyle interventions to prevent adult disease) and geographical (e.g., high-income countries) focuses, and in qualitative methods used (e.g., focus group). While 78 studies demonstrated meaningful engagement of children according to our criteria, there were substantial reporting gaps and there was an emphasis on older age (rather than experience) as a marker of capability and expertise. CONCLUSIONS: Despite evidence of children\u27s meaningful participation, topical, geographical, and methodological gaps were identified, as was the need to strengthen researchers\u27 skills in interpreting and representing children\u27s perspectives and experiences. Based on these findings, the authors present a summary reflective guide to support researchers toward more meaningful child participation in intervention research

Assessment of changes in ecosystem service delivery:a historical perspective on catchment landscapes

Although the relationships between habitats and ecosystem services (ESs) have been acknowledged, investigating spatio-temporal change in these has received far less attention. This study assesses the influence of habitat changes on ES delivery across space and time, based on two time points some 60 years apart, 1946 and 2009. A 1946 aerial photo coverage of two catchments in Scotland was used to construct digital photo mosaics which were then visually interpreted and digitised to derive historic habitat maps. Using the Spatial Evidence for Natural Capital Evaluation (SENCE) mapping approach, the derived habitat maps were translated into ES maps. These were then compared with contemporary ES maps of the two catchments, using the same mapping methodology. Increases in provisioning ESs were associated with increases in intensively managed habitats, with reductions in supply capacity of other regulating and supporting ESs associated with loss of semi-natural habitats. ES delivery was affected not only by gross area changes in habitats over time, but also by changes in configuration and spatial distribution of constituent habitats, including fragmentation and connectivity. It is argued that understanding historic changes in ESs adds an important strand in providing baselines to inform options for current and future management of catchments

North Atlantic evidence for a for a unipolar icehouse climate state at the Eocene-Oligocene Transition

This is the final version. Available from Wiley via the DOI in this record.Earth’s climate transitioned from a warm unglaciated state to a colder glaciated ‘icehouse’ state during the Cenozoic. Extensive ice sheets were first sustained on Antarctica at the Eocene-Oligocene Transition (EOT, ~34 Ma), but there is intense debate over whether Northern Hemisphere ice sheets developed simultaneously at this time, or tens of millions of years later. Here we report on EOT-age sediments that contain detrital sand from Integrated Ocean Drilling Program (IODP) Sites U1406 and U1411 on the Newfoundland margin. These sites are ideally located to test competing hypotheses of the extent of Arctic glaciation, being situated in the North Atlantic’s 'iceberg alley' where icebergs, calved from both the Greenland Ice Sheet today, and the Laurentide Ice Sheet during the Pleistocene, are concentrated by the Labrador Current and deposit continentally-derived detritus. Here we show that detrital sand grains present in these EOT-aged sediments from the Newfoundland margin, initially interpreted to represent ice rafting, were sourced from the mid-latitudes of North America. We find that these grains were transported to the western North Atlantic by fluvial and downslope processes, not icebergs, and were subsequently reworked and deposited by deep-water contour currents on the Newfoundland margin. Our findings are inconsistent with the presence of extensive ice sheets on southern and western Greenland, and the northeastern Canadian Arctic. This contradicts extensive bipolar glaciation at the EOT. The unipolar icehouse arose because of contrasting latitudinal continental configurations at the poles, requiring more intense Cenozoic climatic deterioration to trigger extensive Northern Hemisphere glaciation.Royal Societ

Chronic hypoxemia increases myocardial cytochrome oxidase

ObjectiveCyanotic patients have potentially decreased tissue oxygen tension. Cytochrome oxidase catalyzes the reduction of oxygen and is integral to adenosine triphosphate production. Cytochrome oxidase subunit I, the active site, is encoded by mitochondrial DNA. Using a newborn swine model of chronic hypoxemia, we evaluated ventricular cytochrome oxidase subunit I mRNA and protein expression and assessed cytochrome oxidase activity.MethodsThirty-two newborn piglets underwent thoracotomy and placement of a pulmonary artery–to–left atrium shunt or sham operation. Two weeks later, partial pressure of arterial oxygen, hematocrit, and left ventricular shortening fraction values were compared with baseline values. Northern blot hybridization and protein immunoblotting for ventricular cytochrome oxidase subunit I were performed. Cytochrome oxidase kinetic activity was measured. Heme a,a3 content and turnover number were determined. Significance was assessed with a t test.ResultsBaseline partial pressure of arterial oxygen and hematocrit values were similar. Hypoxemic piglets had a lower partial pressure of arterial oxygen of 38 ± 10 mm Hg (P < .001) and higher hematocrit value of 31.4% ± 2.9% (P < .001) compared with a partial pressure of arterial oxygen of 140 ± 47 mm Hg and hematocrit value of 24.6% ± 3.9% after the sham operation. Baseline and postprocedure left ventricular shortening fraction were similar within and between groups. Chronic hypoxemia increased right ventricular and left ventricular cytochrome oxidase I mRNA and protein by more than 1.4-fold. Cytochrome oxidase activity increased significantly in hypoxemia by 2.5-fold compared with that seen after the sham operation. Heme a,a3 content and turnover number increased by 1.5-fold during hypoxemia.ConclusionsChronic hypoxemia increases cytochrome oxidase I message, protein expression, and activity. The increase in kinetics was due to increased enzyme content and catalytic activity. This is a possible adaptive mechanism that might preserve organ function during chronic hypoxemia

Exploring common stressors in physical education

Daily stressors, or hassles, refer to the everyday environmental demands that constitute a threat or challenge, or exceed an individual’s biological or psychological capacities (Cohen et al., 1995). Increasing evidence suggests that daily stressors have a significant impact on adolescents’ educational outcomes, for example, performance, wellbeing and negative attitudes toward school, however there is limited research examining the concept of common stressors in PE lessons. As early-adolescence is a developmental period associated with decreased engagement in PE, it is important to identify the environmental stressors that may be associated with increased disengagement. The study comprised 54 secondary school students and six PE teachers from five schools in the English Midlands. Semi-structured focus groups were conducted and a thematic analysis was applied to interview transcripts. Three higher order themes were identified from the data: the social environment, the physical and organisational environment, and the performance environment. Common stressors within the social environment included, interpersonal transactions between peers, differences in effort levels during PE, and working outside one’s peer group. Stressors within the physical and organisational environment consisted of, environmental situations within the changing facilities and the availability of activities. Finally, performance environment stressors included, situations involving the difficult acquisition of physical skills, and situations where physical appearance and physical competencies were exposed. The study extends previous findings by identifying potentially threatening and frustrating, environmental demands that have not been identified in the previous literature. The current study is the first to explore the typical stressors that are experienced by students in PE