66 research outputs found
High Temperature Ferromagnetism in CrPtP
We present the growth and basic magnetic and transport properties of
CrPtP. We show that single crystals can readily be grown from a
high-temperature solution created by adding dilute quantities of Cr to Pt-P
based melts. Like other 1-5-1 compounds, CrPtP adopts a
tetragonal P4/mmm structure composed face-sharing CrPt like slabs that are
broken up along the c-axis by sheets of P atoms. EDS and X-ray diffraction
measurements both suggest CrPtP has mixed occupancy between Cr
and Pt atoms, similar to what is found in the closely related compound
CrPt, giving real compositions of CrPtP (x = 0.5). We
report that CrPtP orders ferromagnetically at T = 464.5 K
with a saturated moment of 2.1 /Cr at 1.8 K. Likely
owing to the strong spin-orbit coupling associated with the large quantity of
high Z Pt atoms, CrPtP has exceptionally strong planar
anisotropy with estimated anisotropy fields of 345 kOe and 220 kOe at 1.8 K and
300 K respectively. The resistance of CrPtP has a metallic
temperature dependence with relatively weak magnetoresistance. Electronic band
structure calculations show that CrPtP has a large peak in the density of
states near the Fermi level which is split into spin majority and minority
bands in the ferromagnetic state. Furthermore, the calculations suggest
substantial hybridization between Cr-3d and Pt-5d states near the Fermi level,
in agreement with the experimentally measured anisotropy
Mn(PtPd)P: Isovalent Tuning of Mn Sublattice Magnetic Order
We report the growth and characterization of MnPdP, a ferromagnet with
T 295 K, and conduct a substitutional study with its
antiferromagnetic analogue MnPtP. We grow single crystals of MnPdP and
Mn(PtPd)P by adding Mn into (PtPd)-P based melts.
All compounds in the family adopt the layered anti-CeCoIn structure with
space group P4/mmm, and EDS and XRD results indicate that MnPtP and
MnPdP form a solid solution. Based on magnetization and resistance data, we
construct a T-x phase diagram for Mn(PtPd)P and demonstrate the
antiferromagnetic order found in MnPtP is extraordinarily sensitive to Pd
substitution. At low Pd fractions (x 0.010), the single antiferromagnetic
transition in pure MnPtP splits into a higher temperature ferromagnetic
transition followed on cooling by a lower temperature ferromagnetic to
antiferromagnetic transition and then by a re-entrant antiferromagnetic to
ferromagnetic transition at lower temperatures. The antiferromagnetic region
makes up a bubble that persists to x 0.009 for T 150 K,
with all samples x 0.009 recovering their initial ferromagnetic state with
further cooling to base temperature. Over the same low x range we find a
non-monotonic change in the room temperature unit cell volume, further
suggesting that pure MnPtP is close to an instability. Once x 0.010,
Mn(PtPd)P undergoes a single ferromagnetic transition. The
Curie temperature increases rapidly with x, rising from T 197 K
at x = 0.013 to a maximum of T 312 K for x 0.62, and
then falls back to T 295 K for pure MnPdP (x = 1). Given that
Pt and Pd are isoelectronic, this work raises questions as to the origin of the
extreme sensitivity of the magnetic ground state in MnPtP upon introducing
Pd
Perceptions and experiences of interventions to prevent postnatal depression: a systematic review and qualitative evidence synthesis
Background
More women experience depressive symptoms antenatally than postnatally. Supporting women through the antenatal period is recognised as important in mitigating negative outcomes and in preventing postnatal depression (PND). A systematic review was conducted which aimed to provide a detailed service user and service provider perspective on the uptake, acceptability, and perception of harms of antenatal interventions and postnatal interventions for preventing PND.
Methods
A comprehensive literature search was conducted in 12 major bibliographic databases in November 2012 and updated in December 2014. Studies were included if they contained qualitative evidence on the perspectives and attitudes of pregnant women and postnatal women who had taken part in, or healthcare professionals (HCPs) involved in delivering, preventive interventions for PND.
Results
Twenty-two studies were included. Support and empowerment through education were identified as particularly helpful to women as intervention components, across all intervention types. Implications for accessing the service, understanding the remit of the service and women's preferences for group and individual care also emerged.
Limitations
The majority of the included studies were of moderate or low quality, which may result in a lack of rich data consistently across all studies, limiting to some degree interpretations that can be made.
Conclusion
The synthesis demonstrated important considerations for devising new interventions or adapting existing interventions. Specifically, it is important that individual or group interventions are carefully tailored to women's needs or preferences and women are aware of the remit of the HCPs role to ensure they feel able to access the support required
The Hummingbird Project: A Positive Psychology Intervention for Secondary School Students
Mental health in schools has attracted a lot of attention in recent years. Positive Psychology Interventions (PPIs) in secondary schools have been shown to improve mental health outcomes for students. Previous PPIs have tended to be delivered by trained Psychology specialists or have tended to focus on a single aspect of Positive Psychology such as Mindfulness. The current study involved 2 phases. Phase 1 was a pilot PPI, delivered by current university students in Psychology, which educated secondary school students (N = 90) in a variety of Positive Psychology concepts. Phase 2 involved delivering the PPI to secondary school students (N = 1,054). This PPI, the Hummingbird Project, led to improvements in student well-being, as measured by the World Health Organization Well-Being Index (WHO-5). The intervention also led to improvements in student resilience, as measured by the Bolton Uni-Stride Scale (BUSS), and hope, as measured by the Childrenâs Hope Scale (CHS). Results are discussed in the context of their implications for the future of psychological intervention in secondary school settings
The association between levels of alcohol consumption and mental health problems and academic performance among young university students
Purpose: Mental health problems and harmful alcohol consumption have been found to be high among young university students compared to the general population in Australia. This research aimed to investigate the association between levels of drinking and mental health problems and academic performance among university students aged 18 to 24 years. Methods: This study used a quantitative cross-sectional design using data that were collected in 2014 as part of the Youth Alcohol Project (YAP). Participants were randomly drawn from a cross sectional sample of 6000 undergraduate students. Included in the study were only students who were within the age of 18-24, undergraduate, and internally enrolled at the main campus. A total of 2518 undergraduate students aged 18 to 24 years who were enrolled internally at Curtin University Bentley campus were randomly recruited. Data were collected through an online survey. Students were invited to participate in the study through their student email address. The email invitations coincided with the release of semester results to increase the likelihood of students accessing their emails. A further 628 students were randomly recruited through face to face intercept survey during the campus market days. Data were collected by trained research assistants. Validated instruments were used to collected data on levels of alcohol consumption, mental health, and academic performance. Results: A considerable proportion of participants (44%) reported consuming alcohol at hazardous or harmful levels. Multiple logistic regression analysis showed that students who were consuming alcohol at hazardous levels were 1.2 times more likely to report psychological distress than those with lower levels of alcohol consumption (aOR 1.2, 95% CI: 1.1-1.5). In addition, being late for class (aOR 1.7, 95% CI:1.1-2.4), missing classes (aOR = 2.6, 95% CI: 1.9-2.6), inability to concentrate in class (aOR = 2.6, 95% CI: 1.9-3.4), and inability to complete assignments (aOR = 3.5, 95% CI 2.0-6.0) independently predicted for moderate or hazardous alcohol consumption. Conclusion: The study shows that a considerable proportion of undergraduate students at university consume alcohol at hazardous or harmful levels. In addition, high levels of alcohol consumption are associated with poor academic performance and mental health outcomes among students. The results of the study warrant multi-strategy interventions that focus on policy, organisational, educational, environmental and economic strategies that will help to reduce alcohol related harms among university students
Parents' experiences of caring for a child with a cleft lip and/or palate: A review of the literature
Local and regional components of aerosol in a heavily trafficked street canyon in central London derived from PMF and cluster analysis of single-particle ATOFMS spectra.
Positive matrix factorization (PMF) has been applied to single particle ATOFMS spectra collected on a six lane heavily trafficked road in central London (Marylebone Road), which well represents an urban street canyon. PMF analysis successfully extracted 11 factors from mass spectra of about 700,000 particles as a complement to information on particle types (from K-means cluster analysis). The factors were associated with specific sources and represent the contribution of different traffic related components (i.e., lubricating oils, fresh elemental carbon, organonitrogen and aromatic compounds), secondary aerosol locally produced (i.e., nitrate, oxidized organic aerosol and oxidized organonitrogen compounds), urban background together with regional transport (aged elemental carbon and ammonium) and fresh sea spray. An important result from this study is the evidence that rapid chemical processes occur in the street canyon with production of secondary particles from road traffic emissions. These locally generated particles, together with aging processes, dramatically affected aerosol composition producing internally mixed particles. These processes may become important with stagnant air conditions and in countries where gasoline vehicles are predominant and need to be considered when quantifying the impact of traffic emissions.This is the author accepted manuscript. The final version is available via ACS at http://pubs.acs.org/doi/abs/10.1021/es506249z
A systematic review, evidence synthesis and meta-analysis of quantitative and qualitative studies evaluating the clinical effectiveness, the cost-effectiveness, safety and acceptability of interventions to prevent postnatal depression
Background: Postnatal depression (PND) is a major depressive disorder in the year following childbirth, which impacts on women, their infants and their families. A range of interventions has been developed to prevent PND.
Objectives: To (1) evaluate the clinical effectiveness, cost-effectiveness, acceptability and safety of antenatal and postnatal interventions for pregnant and postnatal women to prevent PND; (2) apply rigorous methods of systematic reviewing of quantitative and qualitative studies, evidence synthesis and decision-analytic modelling to evaluate the preventive impact on women, their infants and their families; and (3) estimate cost-effectiveness.
Data sources: We searched MEDLINE, EMBASE, Science Citation Index and other databases (from inception to July 2013) in December 2012, and we were updated by electronic alerts until July 2013.
Review methods: Two reviewers independently screened titles and abstracts with consensus agreement. We undertook quality assessment. All universal, selective and indicated preventive interventions for pregnant women and women in the first 6 postnatal weeks were included. All outcomes were included, focusing on the Edinburgh Postnatal Depression Scale (EPDS), diagnostic instruments and infant outcomes. The quantitative evidence was synthesised using network meta-analyses (NMAs). A mathematical model was constructed to explore the cost-effectiveness of interventions contained within the NMA for EPDS values.
Results: From 3072 records identified, 122 papers (86 trials) were included in the quantitative review. From 2152 records, 56 papers (44 studies) were included in the qualitative review. The results were inconclusive. The most beneficial interventions appeared to be midwifery redesigned postnatal care [as shown by the mean 12-month EPDS score difference of â1.43 (95% credible interval â4.00 to 1.36)], person-centred approach (PCA)-based and cognitiveâbehavioural therapy (CBT)-based intervention (universal), interpersonal psychotherapy (IPT)-based intervention and education on preparing for parenting (selective), promoting parentâinfant interaction, peer support, IPT-based intervention and PCA-based and CBT-based intervention (indicated). Women valued seeing the same health worker, the involvement of partners and access to several visits from a midwife or health visitor trained in person-centred or cognitiveâbehavioural approaches. The most cost-effective interventions were estimated to be midwifery redesigned postnatal care (universal), PCA-based intervention (indicated) and IPT-based intervention in the sensitivity analysis (indicated), although there was considerable uncertainty. Expected value of partial perfect information (EVPPI) for efficacy data was in excess of ÂŁ150M for each population. Given the EVPPI values, future trials assessing the relative efficacies of promising interventions appears to represent value for money.
Limitations: In the NMAs, some trials were omitted because they could not be connected to the main network of evidence or did not provide EPDS scores. This may have introduced reporting or selection bias. No adjustment was made for the lack of quality of some trials. Although we appraised a very large number of studies, much of the evidence was inconclusive.
Conclusions: Interventions warrant replication within randomised controlled trials (RCTs). Several interventions appear to be cost-effective relative to usual care, but this is subject to considerable uncertainty.
Future work recommendations: Several interventions appear to be cost-effective relative to usual care, but this is subject to considerable uncertainty. Future research conducting RCTs to establish which interventions are most clinically effective and cost-effective should be considered
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