104 research outputs found

    Fiber optic control system integration

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    A total fiber optic, integrated propulsion/flight control system concept for advanced fighter aircraft is presented. Fiber optic technology pertaining to this system is identified and evaluated for application readiness. A fiber optic sensor vendor survey was completed, and the results are reported. The advantages of centralized/direct architecture are reviewed, and the concept of the protocol branch is explained. Preliminary protocol branch selections are made based on the F-18/F404 application. Concepts for new optical tools are described. Development plans for the optical technology and the described system are included

    Optimization of Plasmas for Recombination-Pumped Short-Wavelength Lasers

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    We report on experiments investigating the optimization of laser-ablated plasmas which are used to produce recombination-pumped, short-wavelength lasers. We evaluate the density of electrons and neutral atoms in laser ablated lithium and carbon plasmas as a function of time and distance away from the ablated target surface. We use an interferometric technique which can reveal information about the temperature of the plasma electrons. We find that the cold electrons which result in gain in recombination-pumped lithium lasers on the Lyman-α transition are produced by the high-intensity pump pulse rather than the lower intensity ablating pulse

    Making a splash with water repellency

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    A 'splash' is usually heard when a solid body enters water at large velocity. This phenomena originates from the formation of an air cavity resulting from the complex transient dynamics of the free interface during the impact. The classical picture of impacts on free surfaces relies solely on fluid inertia, arguing that surface properties and viscous effects are negligible at sufficiently large velocities. In strong contrast to this large-scale hydrodynamic viewpoint, we demonstrate in this study that the wettability of the impacting body is a key factor in determining the degree of splashing. This unexpected result is illustrated in Fig.1: a large cavity is evident for an impacting hydrophobic sphere (1.b), contrasting with the hydrophilic sphere's impact under the very same conditions (1.a). This unforeseen fact is furthermore embodied in the dependence of the threshold velocity for air entrainment on the contact angle of the impacting body, as well as on the ratio between the surface tension and fluid viscosity, thereby defining a critical capillary velocity. As a paradigm, we show that superhydrophobic impacters make a big 'splash' for any impact velocity. This novel understanding provides a new perspective for impacts on free surfaces, and reveals that modifications of the detailed nature of the surface -- involving physico-chemical aspects at the nanometric scales -- provide an efficient and versatile strategy for controlling the water entry of solid bodies at high velocity.Comment: accepted for publication in Nature Physic

    Evaluation of a Tobacco Educational Intervention for Pregnant Alaska Native Women

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    Tobacco cessation interventions developed and evaluated for Alaska Native women do not exist. As part of routine clinical care provided at a prenatal visit, a brief tobacco educational intervention for Alaska Native pregnant women (N=100; mean ± SD age = 25.9±6.2 years; mean 6.3± 2.6 months gestation) was piloted at the Y-K Delta Regional Hospital in Bethel, Alaska. This retrospective study reports on the evaluation of this clinical program. The intervention was consistent with the clinical practice guidelines (i.e., 5 A’s – ask, advise, assess, assist, arrange), with an average duration of 20.2 ± 6.8 minutes. The self-reported tobacco abstinence rate following the intervention was 11% at the last prenatal visit and 12% at delivery. Delivering a tobacco cessation intervention at a prenatal visit is feasible, but there is a need to identify more effective interventions for Alaska Native pregnant women

    Supporting perinatal anxiety in the digital age; a qualitative exploration of stressors and support strategies

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    Background The period surrounding childbirth is one of profound change, which can often be experienced as stressful and overwhelming. Indeed, around 20% of women may experience significant levels of anxiety in the perinatal period. However, most women experiencing perinatal anxiety (PNA) go unrecognised and untreated. The Internet offers a potentially scalable solution to improve access to support, however a dearth of research in this area means that work is needed to better understand women’s experience of PNA, so that potential targets for intervention can be identified and possible barriers to support overcome. This study aimed to qualitatively explore women’s experience of anxiety triggers and support in the perinatal period; and gain insight into what online support is acceptable for women with PNA. Methods Women who were either pregnant or within one-year postpartum were invited to participate in focus groups across the UK. Focus groups were used to allow a diversity of perspectives to be heard, while simultaneously promoting the identification and prioritisation of important support needs and solutions. Interviews were transcribed and thematically analysed. Results Five key themes emerged in relation to women’s experience with PNA: holding unrealistic expectations of birth and motherhood; stigma; the importance of peer support; uncertainty and poor maternal confidence; and a lack of mental health support and knowledge. Perinatal women felt under-supported and poorly prepared for motherhood. A mismatch between their expectations and the reality of their experience, alongside a pressure to be the ‘perfect mum’ was the primary source of their anxiety. Furthermore, stigma associated with PNA may have exacerbated these issues and led to help-seeking avoidance. Overall, women felt these issues could be addressed via online support, through the delivery of more realistic information, providing psychoeducation about PNA symptoms and management, and the inclusion of authentic peer experiences. Thus, delivering evidence-based information and interventions online may provide a solution that is acceptable to this cohort. Conclusions This work provides unique insight into potential sources of anxiety for women in the perinatal period, while also offering potential internet-based support solutions that are likely to be acceptable and helpful for women with PNA

    Internal Medicine Residents Reject “Longer and Gentler” Training

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    BACKGROUND: Increasing complexity of medical care, coupled with limits on resident work hours, has prompted consideration of extending Internal Medicine training. It is unclear whether further hour reductions and extension of training beyond the current duration of 3 years would be accepted by trainees. OBJECTIVE: We aimed to determine if further work-hour reductions and extension of training would be accepted by trainees and whether resident burnout affects their opinions. DESIGN: A postal survey was sent to all 143 Internal Medicine residents at the University of Colorado School of Medicine in May 2004. MEASUREMENTS: The survey contained questions related to opinions on work-hour limits using a 5-point Likert scale ranging from strongly agree to strongly disagree. Burnout was measured using the Maslach Burnout Inventory, organized into three subscales: emotional exhaustion (EE), depersonalization (DP), and personal accomplishment, with burnout defined as high EE or DP. RESULTS: Seventy-four percent (106/143) of residents returned the survey. The vast majority (84%) of residents disagreed or strongly disagreed with extending training to 4 or 5 years. Burnout residents were less averse to extending training (strongly agree or agree, 18.9% vs 4.3%, P = .04). The majority of residents (68.9%) disagreed or strongly disagreed with establishing a 60-hour/week limit. Residents who met the criteria for burnout were more likely to agree that a 60-hour limit would be better than an 80-hour limit (strongly agree or agree, 22% vs 8%, P = .02). CONCLUSIONS: In this program, most Internal Medicine residents are strongly opposed to extending their training to 4 or 5 years and would prefer the current 80 hours/week cap. A longer, less intense pace of Internal Medicine training seems to be less attractive in the eyes of current trainees

    Maternal psychological distress in primary care and association with child behavioural outcomes at age three

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    Observational studies indicate children whose mothers have poor mental health are at increased risk of socio-emotional behavioural difficulties, but it is unknown whether these outcomes vary by the mothers’ mental health recognition and treatment status. To examine this question, we analysed linked longitudinal primary care and research data from 1078 women enrolled in the Born in Bradford cohort. A latent class analysis of treatment status and self-reported distress broadly categorised women as (a) not having a common mental disorder (CMD) that persisted through pregnancy and the first 2 years after delivery (N = 756, 70.1 %), (b) treated for CMD (N = 67, 6.2 %), or (c) untreated (N = 255, 23.7 %). Compared to children of mothers without CMD, 3-year-old children with mothers classified as having untreated CMD had higher standardised factor scores on the Strengths and Difficulties Questionnaire (d = 0.32), as did children with mothers classified as having treated CMD (d = 0.27). Results were only slightly attenuated in adjusted analyses. Children of mothers with CMD may be at risk for socio-emotional and behavioural difficulties. The development of effective treatments for CMD needs to be balanced by greater attempts to identify and treat women. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00787-015-0777-2) contains supplementary material, which is available to authorized users

    Evaluation of expressive writing for postpartum health: A randomized controlled trial

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    Pregnancy, birth and adjusting to a new baby is a potentially stressful time that can negatively affect the health of women. There is some evidence that expressive writing can have positive effects on psychological and physical health, particularly during stressful periods. The current study aimed to evaluate whether expressive writing would improve women’s postpartum health. A randomized controlled trial was conducted with three conditions: expressive writing (n=188), a control writing task (n=213), or normal care (n=163). Measures of psychological health, physical health and quality of life were measured at baseline (6-12 weeks postpartum), 1 month and 6 months later. Ratings of stress were taken before and after the expressive writing task. Intent-to-treat analyses showed no significant differences between women in the expressive writing, control writing and normal care groups on measures of physical health, anxiety, depression, mood or quality of life at 1 and 6 months. Uptake and adherence to the writing tasks was low. However, women in the expressive writing group rated their stress as significantly reduced after completing the task. Cost analysis suggest women who did expressive writing had the lowest costs in terms of healthcare service use and lowest cost per unit of improvement in quality of life. Results suggest expressive writing is not effective as a universal intervention for all women 6-12 weeks postpartum. Future research should examine expressive writing as a targeted intervention for women in high-risk groups, such as those with mild or moderate depression, and further examine cost-effectiveness

    Feasibility and acceptability of expressive writing with postpartum women: a randomised controlled trial

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    Abstract Background: Pregnancy, birth and adjusting to a new baby is a potentially stressful time that can negatively affect women’s mental and physical health. Expressive writing, where people write about a stressful event for at least 15 minutes on three consecutive days, has been associated with improved health in some groups but it is not clear whether it is feasible and acceptable for use with postpartum women. This study therefore examined the feasibility and acceptability of expressive writing for postpartum women as part of a randomised controlled trial (RCT). Methods: The Health After Birth Trial (HABiT) was an RCT evaluating expressive writing for postpartum women which included measures of feasibility and acceptability. At 6 to 12 weeks after birth 854 women were randomised to expressive writing, a control writing task or normal care, and outcome measures of health were measured at baseline, one month later and six months later. Feasibility was measured by recruitment, attrition, and adherence to the intervention. Quantitative and qualitative measures of acceptability of the materials and the task were completed six months after the intervention. Results: Recruitment was low (10.7% of those invited to participate) and the recruited sample was from a restricted sociodemographic range. Attrition was high, increased as the study progressed (35.8% at baseline, 57.5% at one month, and 68.1% at six months) and was higher in the writing groups than in the normal care group. Women complied with instructions to write expressively or not, but adherence to the instruction to write for 15 minutes per day for three days was low (Expressive writing: 29.3%; Control writing: 23.5%). Acceptability measures showed that women who wrote expressively rated the materials/task both more positively and more negatively than those in the control writing group, and qualitative comments revealed that women enjoyed the writing and/or found it helpful even when it was upsetting. Conclusions: The feasibility of offering expressive writing as a universal self-help intervention to all postpartum women 6 to 12 weeks after birth in the HABiT trial was low, but the expressive writing intervention was acceptable to the majority of women who completed it

    The Postpartum Specific Anxiety Scale: development and preliminary validation

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    Perinatal symptoms of anxiety are increasingly recognised due to their high prevalence and impact. Studies using pregnancy-specific anxiety measures have found that they may predict perinatal outcomes more effectively than general measures. However, no such measure exists to assess anxieties specific to the postpartum. This study aimed to develop and validate a measure (Postpartum Specific Anxiety Scale; PSAS) that accurately represents the specific anxieties faced by postpartum women, using a four-stage methodology: (1) 51 items were generated from interviews conducted with a group of 19 postpartum women at two time points, (2) the scale was reviewed and refined by a diverse expert panel, (3) an online pilot study (n = 146) was conducted to assess comprehensibility and acceptability and (4) an online sample of 1282 mothers of infants up to 6 months old completed the PSAS against a battery of convergent measures. A subsample (n = 262) repeated the PSAS 2 weeks later. The PSAS possessed good face and content validity and was comprehensible and acceptable to postpartum women. PSAS scores were significantly correlated with other measures indicating good convergent validity. Principal component analyses (PCA) revealed a simple four-factor structure. Reliability of the overall scale and individual PSAS factors proved to be good to excellent. A preliminary receiver operating characteristic (ROC) analysis also suggested that the PSAS may be a useful screening tool. The psychometric evidence suggests that the PSAS is an acceptable, valid, and reliable research tool to assess anxieties, which are specific to the postpartum period. Next steps in the iterative validation process are considered for both research and screening purposes
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