Exchange bias and interface electronic structure in Ni/Co3O4(011)

A detailed study of the exchange bias effect and the interfacial electronic structure in Ni/Co3O4(011) is reported. Large exchange anisotropies are observed at low temperatures, and the exchange bias effect persists to temperatures well above the Neel temperature of bulk Co3O4, of about 40 K: to ~80 K for Ni films deposited on well ordered oxide surfaces, and ~150 K for Ni films deposited on rougher Co3O4 surfaces. Photoelectron spectroscopy measurements as a function of Ni thickness show that Co reduction and Ni oxidation occur over an extended interfacial region. We conclude that the exchange bias observed in Ni/Co3O4, and in similar ferromagnetic metallic/Co3O4 systems, is not intrinsic to Co3O4 but rather due to the formation of CoO at the interface.Comment: 8 pages, 6 figures. Accepted for publication in Physical Review B

‘It would be okay if they came through the proper channels’: community perceptions and attitudes toward asylum seekers in Australia

Australia\u27s humanitarian programme contributes to UNHCR\u27s global resettlement programme and enhances Australia\u27s international humanitarian reputation. However, as the recent tragedy on Christmas Island has shown, the arrival of asylum seekers by boat continues to stimulate debate, discussion and reaction from the Australian public and the Australian media. In this study, we used a mixed methods community survey to understand community perceptions and attitudes relating to asylum seekers. We found that while personal contact with asylum seekers was important when forming opinions about this group of immigrants, for the majority of respondents, attitudes and opinions towards asylum seekers were more influenced by the interplay between traditional Australian values and norms, the way that these norms appeared to be threatened by asylum seekers, and the way that these threats were reinforced both in media and political rhetoric

Wear of human teeth: a tribological perspective

The four main types of wear in teeth are attrition (enamel-on-enamel contact), abrasion (wear due to abrasive particles in food or toothpaste), abfraction (cracking in enamel and subsequent material loss), and erosion (chemical decomposition of the tooth). They occur as a result of a number of mechanisms including thegosis (sliding of teeth into their lateral position), bruxism (tooth grinding), mastication (chewing), toothbrushing, tooth flexure, and chemical effects. In this paper the current understanding of wear of enamel and dentine in teeth is reviewed in terms of these mechanisms and the major influencing factors are examined. In vitro tooth wear simulation and in vivo wear measurement and ranking are also discussed

The effectiveness of an intensive individual tutoring programme (Numbers Count) delivered individually or to small groups of children: a randomised controlled trial

Introduction: In this article, we present the results of two small randomised controlled trials (RCTs) investigating the relative efficacy of a one-to-one numeracy programme, Numbers Count (NC). This intervention was developed as part of the Every Child Counts programme to specifically target the lowest achieving children at key stage 1 (KS1) mathematics. The research question focused on the relative efficacy of NC delivered either individually (as originally intended by the developers of the programme) or in an adapted version to small groups of two or three children. Design and methods: In 15 schools 75 children in year 2 identified by the schools as being eligible to receive NC were randomised to receive it individually or in pairs and in 7 schools 54 children in year 2 identified by the schools as being eligible to receive NC were randomised to receive it individually or in triplets during the school year 2009–2010. The design of the trial required five children, for the pairs sub-trial, or seven children for the triplets sub-trial in each school to receive NC individually or in pairs/triplets in autumn term 2009 or spring term 2010. Results: The primary outcome measure Progress in Maths 6 (PIM 6) was undertaken and marked blind to group allocation by independent testers. We found no statistically significant difference between the scores of the children taught individually or in pairs in terms of PIM 6 scores although a slight difference in favour of pairs was observed. We also found no statistically significant differences between children taught individually or in triplets in terms of PIM 6 scores. We pooled the effect sizes for individual versus pairs and triplets delivery in a meta-analysis of individual versus small group teaching. The pooled effect size was −.26 (CI −2.18 to 1.65) which demonstrates no statistically significant difference between individual and small group teaching. Conclusion: There was no evidence of a difference between the groups, which was not unexpected as our sample sizes were relatively small. This is the only robust evidence from RCTs of the promise of the intervention. However, given the small sample sizes of the trials, we recommend further larger trials should be undertaken comparing small group mathematics teaching with one-to-one educational interventions, using both this programme and others. These two trials could also usefully be included in meta-analyses comparing small group and one-to-one teaching in mathematics education

Generalized ultrasonic scattering model for arbitrary transducer configurations

Ultrasonic scattering in polycrystalline media is directly tied to microstructural features. As a result, modeling efforts of scattering from microstructure have been abundant. The inclusion of beam modeling for the ultrasonic transducers greatly simplified the ability to perform quantitative, fully calibrated experiments. In this article, a theoretical scattering model is generalized to allow for arbitrary source and receiver configurations, while accounting for beam behavior through the total propagation path. This extension elucidates the importance and potential of out-of-plane scattering modes in the context of microstructure characterization. The scattering coefficient is explicitly written for the case of statistical isotropy and ellipsoidal grain elongation, with a direct path toward expansion for increased microstructural complexity. Materials with crystallites of any symmetry can be studied with the present model; the numerical results focus on aluminum, titanium, and iron. The amplitude of the scattering response is seen to vary across materials, and to have varying sensitivity to grain elongation and orientation depending on the transducer configuration selected. The model provides a pathway to experimental characterization of microstructure with optimized sensitivity to parameters of interest

Impact of on-site cardiac catheterization on resource utilization and fatal and non-fatal outcomes after acute myocardial infarction

BACKGROUND: Patterns of care for acute myocardial infarction (AMI) strongly depend on the availability of on-site cardiac catheterization facilities. Although the management found at hospitals without on-site catheterization does not lead to increased mortality, little it known about its impact on resource utilization and non-fatal outcomes. METHODS: We identified all patients (n = 35,289) admitted with a first AMI in the province of Quebec between January 1, 1996 and March 31, 1999 using population-based administrative databases. Medical resource utilization and non-fatal and fatal outcomes were compared among patients admitted to hospitals with and without on-site cardiac catheterization facilities. RESULTS: Cardiac catheterization and PCI were more frequently performed among patients admitted to hospitals with catheterization facilities. However, non-invasive procedures were not used more frequently at hospitals without catheterization facilities. To the contrary, echocardiography [odds ratio (OR), 2.04; 95% confidence interval (CI), 1.93–2.16] and multi-gated acquisition imaging (OR, 1.24; 95% CI, 1.17–1.32) were used more frequently at hospitals with catheterization, and exercise treadmill testing (OR, 1.02; 95% CI, 0.91–1.15) and Sestamibi/Thallium imaging (OR, 0.93; 95% CI, 0.88–0.98) were used similarly at hospitals with and without catheterization. Use of anti-ischemic medications and frequency of emergency room and physician visits, were similar at both types of institutions. Readmission rates for AMI-related cardiac complications and mortality were also similar [adjusted hazard ratio, recurrent AMI: 1.02, 95% CI, 0.89–1.16; congestive heart failure: 1.02; 95% CI, 0.90–1.15; unstable angina: 0.93; 95% CI, 0.85–1.02; mortality: 0.99; 95% CI, 0.93–1.05)]. CONCLUSION: Although on-site availability of cardiac catheterization facilities is associated with greater use of invasive cardiac procedures, non-availability of catheterization did not translate into a higher use of non-invasive tests or have an impact on the fatal and non-fatal outcomes available for study in our administrative database

Neonatal and child mortality data in retrospective population-based surveys compared with prospective demographic surveillance: EN-INDEPTH study.

BACKGROUND: Global mortality estimates remain heavily dependent on household surveys in low- and middle-income countries, where most under-five deaths occur. Few studies have assessed the accuracy of mortality data or determinants of capturing births in surveys. METHODS: The Every Newborn-INDEPTH study (EN-INDEPTH) included a large, multi-country survey of women aged 15-49 interviewed about livebirths and their survival status in five Health and Demographic Surveillance Systems (HDSSs). The HDSSs undertake regular household visits to register births and deaths for a given population. We analysed EN-INDEPTH survey data to assess background factors associated with not recalling a complete date-of-birth. We calculated Kaplan-Meier survival estimates for both survey and HDSS data and describe age-at-death distributions during the past 5 years for children born to the same women. We assessed the proportion of HDSS-births that could be matched on month-of-birth to survey-births and used regression models to identify factors associated with matching. RESULTS: 69,176 women interviewed in the survey reported 109,817 births and 3064 deaths in children under 5 years in the 5 years prior to the survey. In the HDSS data, the same women had 83,768 registered births and 2335 under-five deaths in the same period. A complete date-of-birth was not reported for 1-7% of survey-births. Birthdates were less likely to be complete for dead children and children born to women of higher parity or with little/no education. Distributions of reported age-at-death indicated heaping at full weeks (neonatal period) and at 12 months. Heaping was more pronounced in the survey data. Survey estimates of under-five mortality rates were similar to HDSS estimates of under-five mortality in two of five sites, higher in the survey in two sites (15%, 41%) and lower (24%) in one site. The proportion of HDSS-births matched to survey-births ranged from 51 to 89% across HDSSs and births of children who had died were less likely to be matched. CONCLUSIONS: Mortality estimates in the survey and HDSS were not markedly different for most sites. However, neither source is a "gold standard" and both sources miss some events. Research is required to improve capture and accuracy to better track newborn and child survival targets

Stillbirth maternity care measurement and associated factors in population-based surveys: EN-INDEPTH study.

BACKGROUND: Household surveys remain important sources of maternal and child health data, but until now, standard surveys such as Demographic and Health Surveys (DHS) have not collected information on maternity care for women who have experienced a stillbirth. Thus, nationally representative data are lacking to inform programmes to address the millions of stillbirths which occur annually. METHODS: The EN-INDEPTH population-based survey of women of reproductive age was undertaken in five Health and Demographic Surveillance System sites in Bangladesh, Ethiopia, Ghana, Guinea-Bissau and Uganda (2017-2018). All women answered a full birth history with additional questions on pregnancy losses (FBH+) or full pregnancy history (FPH). A sub-sample, including all women reporting a recent stillbirth or neonatal death, was asked additional maternity care questions. These were evaluated using descriptive measures. Associations between stillbirth and maternal socio-demographic characteristics, babies' characteristics and maternity care use were assessed using a weighted logistic regression model for women in the FBH+ group. RESULTS: A total of 15,591 women reporting a birth since 1 January 2012 answered maternity care questions. Completeness was very high (> 99%), with similar proportions of responses for both live and stillbirths. Amongst the 14,991 births in the FBH+ group, poorer wealth status, higher parity, large perceived baby size-at-birth, preterm or post-term birth, birth in a government hospital compared to other locations and vaginal birth were associated with increased risk of stillbirth after adjusting for potential confounding factors. Regarding association with reported postnatal care, women with a stillbirth were more likely to report hospital stays of > 1 day. However, women with a stillbirth were less likely to report having received a postnatal check compared to those with a live birth. CONCLUSIONS: Women who had experienced stillbirth were able to respond to questions about pregnancy and birth, and we found no reason to omit questions to these women in household surveys. Our analysis identified several potentially modifiable factors associated with stillbirth, adding to the evidence-base for policy and action in low- and middle-income contexts. Including these questions in DHS-8 would lead to increased availability of population-level data to inform action to end preventable stillbirths

Charged Particles in a 2+1 Curved Background

The coupling to a 2+1 background geometry of a quantized charged test particle in a strong magnetic field is analyzed. Canonical operators adapting to the fast and slow freedoms produce a natural expansion in the inverse square root of the magnetic field strength. The fast freedom is solved to the second order. At any given time, space is parameterized by a couple of conjugate operators and effectively behaves as the `phase space' of the slow freedom. The slow Hamiltonian depends on the magnetic field norm, its covariant derivatives, the scalar curvature and presents a peculiar coupling with the spin-connection.Comment: 22 page