113 research outputs found
Structure-Property Correlations in doped Bismuth Ferrite Ceramics
A detailed powder neutron diffraction study coupled with a complementary characterisation of the ferroelectricity and ferromagnetism, concerning two different compositions based on a parent BiFeO3 crystal lattice. The addition of Dy3+ into BiFeO3 ceramics shows how the parent polar R3c symmetry destabilises due to strain, linking to a large size variance between the two A-site cations (Dy3+ and Bi3+). This results in a loss of symmetry to polar Cc followed by a broad competitive phase system between strained Cc and non-polar Pnma symmetries. Increasingly strain on the lattice is seen until x=0.12 at which point the Pnma phase becomes dominant. However, phase co-existence persists until beyond x=0.25. Preliminary magnetisation measurements indicate a developing ferromagnetic character which increases in magnitude with Dy3+ content; electrical measurements suggest that whilst initial compositions of Bi0.95Dy0.05FeO3 show signs of polarity, more Dy3+ rich materials such as Bi0.70Dy0.30FeO3 shows relaxor like characteristics.
This study also examines the addition of Alkali Metal Niobates to BiFeO3, looking at the Bi1-xKxFe1-xNbxO3 solid solution. Despite much individual attention on both BiFeO3 and KNbO3 a solid solution between the two has received less interest. Reported in this work is a detailed neutron and synchrotron X-ray powder diffraction study which demonstrates a polar R3c ? polar P4mm ? polar Amm2 series of structural phase transitions similar to that exhibited by PbZrO3–PbTiO3. Early electrical measurements show a non-ohmic electrode effects, making it difficult to determine the polar nature of the P4mm phase. Preliminary magnetic data suggests that the G-type anti-ferromagnetic spin cycloid may be retained, but some canting may occur, however the exact nature of the magnetic structure is unconfirmed, and evidence may initially suggest paramagnetism, canted antiferromagnetism or a spin glass like structure. All materials seem to exhibit a similar magnetic transition consistent with the parent lattice
Psychotropic medication use in adolescents with intellectual disability living in the community
Purpose Information on the use of psychotropic medications in adolescents with intellectual disability is scant. Such information can guide interventions to improve psychotropic medication use in this population. We investigated the prevalence of, and factors associated with, psychotropic medication use in adolescents with intellectual disability in Australia who live in the community. Methods Cross-sectional data were obtained from adolescents with intellectual disability living in the community in South East Queensland, Australia, between February 2007 and September 2010. Self-reported information on medication use was extracted from a health screening tool. Demographic and medical data were collected through parent/caregiver surveys. Medications were classified according to the Anatomical Therapeutic Chemical classification system. Psychopathology was assessed using the Developmental Behaviour Checklist Short Form. Logistic regression analysis was used to assess the association of demographic and medical characteristics with psychotropic medication use. Results There were 176 participants (median age = 16 years, range = 11–19 years; 55% male). Psychotropics were used by 20% of participants. Psychostimulants were the commonest psychotropic class, used by 9% of participants. Multipsychotropic prescribing was not common with only seven participants using more than one psychotropic agent. After adjusting for potentially confounding variables, use of psychotropic medications was significantly associated with male gender (adjusted odds ratio = 3.6; 95% confidence interval = 1.3–9.5) and having major behaviour problems (3.1; 1.1–8.9). Conclusions Adolescents with intellectual disability use a wide range of psychotropic medications. Being male and having major behaviour problems are associated with the use of psychotropic medications. Research examining the rationale for psychotropic prescribing in this population is needed. Copyright © 2013 John Wiley & Sons, Ltd
Can professional football clubs deliver a weight management programme for women: a feasibility study
Background Levels of obesity remain high in the UK. The Football Fans in Training (FFIT) randomised controlled trial (RCT) demonstrated that a 12-week, gender-sensitised weight management, physical activity and healthy eating group programme delivered through professional football clubs helped men aged 35–65 years with BMI at least 28 kg/m2 lose a clinically-significant amount of weight. We aimed to test the feasibility of a minimally-adapted FFIT programme for delivery to women by assessing recruitment and completion rates; determining if the programme content and delivery required further refinement; and evaluating the potential of FFIT for Women to deliver improvements in weight and other clinical, behavioural and psychological outcomes. Methods A feasibility study of the FFIT for Women programme including before-and-after measurements of clinical (weight, waist, body mass index [BMI], blood pressure) behavioural (self-reported physical activity, food and alcohol intake) and psychological (self-esteem, positive and negative affect, physical and mental HRQoL) outcomes at five professional football clubs. Post-programme focus groups assessed acceptability of the programme format, content and style of delivery for women. Results Recruitment across the five clubs resulted in 123 women aged 35–65 years with BMI at least 28 kg/m2 taking part in the study. The mean weight (95.3 kg) and BMI (36.6 kg/m2) of the cohort were both suggestive of high risk of future disease. Of 123 women who started the programme, 94 (76%) completed it; 72 (58.5%) returned for 12-week follow-up measurements. Participants compared FFIT for Women favourably to commercial weight loss programmes and emphasised the importance of the programme’s physical activity content. They also spoke positively about group dynamics, suggested that the approach to food was less restrictive than in other weight loss approaches, and broadly enjoyed the football setting. Mean weight loss was 2.87 kg (95% CI 2.09, 3.65, p ≤ 0.001). Mean waist reduction was 3.84 cm (2.92, 4.77, p ≤ 0.001). Conclusion In this evaluation, FFIT for Women was feasible, acceptable and demonstrated potential as a weight loss programme. Our findings suggest the programme has the potential to produce outcomes that are on a par with existing commercial and state-funded offerings
MISSION Diversion & Recovery for Traumatized Veterans (MISSION DIRECT VET): Early Findings and Lessons Learned
MISSION DIRECT VET is a SAMHSA- funded, court based diversion program targeting veterans in Massachusetts with trauma-related mental health and substance use problems. MISSION-DIRECT VET seeks to: Reduce criminal justice involvement Treat mental health, substance abuse and other trauma related symptoms Use a systematic wrap-around model Provide care coordination, peer support and trauma informed services Develop interagency partnerships to serve veterans with co-occurring disorder
High Sensitivity Array Observations of the z=1.87 Sub-Millimeter Galaxy GOODS 850-3
We present sensitive phase-referenced VLBI results on the radio continuum
emission from the z=1.87 luminous submillimeter galaxy (SMG) GOODS 850-3. The
observations were carried out at 1.4 GHz using the High Sensitivity Array
(HSA). Our sensitive tapered VLBI image of GOODS 850-3 at 0.47 x 0.34 arcsec
(3.9 x 2.9 kpc) resolution shows a marginally resolved continuum structure with
a peak flux density of 148 \pm 38 uJy/beam, and a total flux density of 168 \pm
73 uJy, consistent with previous VLA and MERLIN measurements. The derived
intrinsic brightness temperature is > 5 \pm 2 x 10^3 K. The radio continuum
position of this galaxy coincides with a bright and extended near-infrared
source that nearly disappears in the deep HST optical image, indicating a dusty
source of nearly 9 kpc in diameter. No continuum emission is detected at the
full VLBI resolution (13.2 x 7.2 mas, 111 x 61 pc), with a 4-sigma point source
upper limit of 26 uJy/beam, or an upper limit to the intrinsic brightness
temperature of 4.7 x 10^5 K. The extent of the observed continuum source at 1.4
GHz and the derived brightness temperature limits are consistent with the radio
emission (and thus presumably the far-infrared emission) being powered by a
major starburst in GOODS 850-3, with a star formation rate of ~2500 M_sun/yr.
Moreover, the absence of any continuum emission at the full resolution of the
VLBI observations indicates the lack of a compact radio AGN source in this
z=1.87 SMG.Comment: 19 pages, 4 figures, accepted for publication in A
CARMA II: A ground vehicle for autonomous surveying of alpha, beta and gamma radiation
Surveying active nuclear facilities for spread of alpha and beta contamination is currently performed by human operators. However, a skills gap of qualified workers is emerging and is set to worsen in the near future due to under recruitment, retirement and increased demand. This paper presents an autonomous ground vehicle that can survey nuclear facilities for alpha, beta and gamma radiation and generate radiation heatmaps. New methods for preventing the robot from spreading radioactive contamination using a state-machine and radiation costmaps are introduced. This is the first robot that can detect alpha and beta contamination and autonomously re-plan around the contamination without the wheels passing over the contaminated area. Radiation avoidance functionality is proven experimentally to reduce alpha and beta contamination spread as well as gamma radiation dose to the robot. The robot’s survey area is defined using a custom designed, graphically controlled area coverage planner. It was concluded that the robot is highly suited to certain monotonous room scale radiation surveying tasks and therefore provides the opportunity for financial savings, to mitigate a future skills gap, and provision of radiation surveys that are more granular, accurate and repeatable than those currently performed by human operators
Positioning aquatic animals with acoustic transmitters
Geolocating aquatic animals with acoustic tags has been ongoing for decades, relying on the detection of acoustic signals at multiple receivers with known positions to calculate a 2D or 3D position, and ultimately recreate the path of an aquatic animal from detections at fixed stations.This method of underwater geolocation is evolving with new software and hardware options available to help investigators design studies and calculate positions using solvers based predominantly on time-difference-of-arrival and time-of-arrival.We provide an overview of the considerations necessary to implement positioning in aquatic acoustic telemetry studies, including how to design arrays of receivers, test performance, synchronize receiver clocks and calculate positions from the detection data. We additionally present some common positioning algorithms, including both the free open-source solvers and the 'black-box' methods provided by some manufacturers for calculating positions.This paper is the first to provide a comprehensive overview of methods and considerations for designing and implementing better positioning studies that will support users, and encourage further knowledge advances in aquatic systems
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