238 research outputs found

    Calibration and performance assessment of an innovative high-temperature cavitometer

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    This paper describes a series of systematic experimental studies to evaluate the performance of a high-temperature cavitometer under well-controlled conditions. The cavitometer was specifically designed for measurements in liquid metals: it operates through a long tungsten waveguide (probe), providing thermal protection to the piezo sensing elements placed outside the hot area, and with sufficient bandwidth to enable the monitoring of broadband acoustic emissions associated with cavitation activity. It was calibrated electrically, and acoustically, at kHz and MHz frequencies, and so can be used to estimate acoustic pressures (in Pa), providing physical, and consequently practical, meaning to cavitation measurements within liquid metals. Results obtained from ultrasonic sources in a cylindrical vessel using water showed that the cavitometer is a reliable and robust device for characterizing direct field acoustic pressures and broadband emissions from the resulting cavitation. Additionally, preliminary characterization of the real-time acoustic pressures during ultrasonic processing of liquid aluminium (Al) in a standard clay-graphite crucible were performed for the first time. The use of the calibrated cavitometer will establish a more generalized approach for measuring the actual acoustic pressures over a broad range of liquid temperatures within a sonicated medium, demonstrating its potential use as a tool for optimizing, controlling, and scaling-up processes

    Measuring the quality and quantity of professional intrapartum support: Testing a computerised systematic observation tool in the clinical setting

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    Background: Continuous support in labour has a significant impact on a range of clinical outcomes, though whether the quality and quantity of support behaviours affects the strength of this impact has not yet been established. To identify the quality and quantity of support, a reliable means of measurement is needed. To this end, a new computerised systematic observation tool, the ‘SMILI' (Supportive Midwifery in Labour Instrument) was developed. The aim of the study was to test the validity and usability of the ‘Supportive Midwifery in Labour Instrument' (SMILI) and to test the feasibility and acceptability of the systematic observation approach in the clinical intrapartum setting. Methods: Systematic observation was combined with a postnatal questionnaire and the collection of data about clinical processes and outcomes for each observed labour. The setting for the study was four National Health Service maternity units in Scotland, UK. Participants in this study were forty five midwives and forty four women. The SMILI was used by trained midwife observers to record labour care provided by midwives. Observations were undertaken for an average of two hours and seventeen minutes during the active first stage of labour and, in 18 cases, the observation included the second stage of labour. Content validity of the instrument was tested by the observers, noting the extent to which the SMILI facilitated the recording of all key aspects of labour care and interactions. Construct validity was tested through exploration of correlations between the data recorded and women's feelings about the support they received. Feasibility and usability data were recorded following each observation by the observer. Internal reliability and construct validity were tested through statistical analysis of the data. Results: One hundred and four hours of labour care were observed and recorded using the SMILI during forty nine labour episodes. Conclusion: The SMILI was found to be a valid and reliable instrument in the intrapartum setting in which it was tested. The study identified that the SMILI could be used to test correlations between the quantity and quality of support and outcomes. The systematic observational approach was found to be an acceptable and feasible method of enquiry

    Regional and large-scale patterns in Amazon forest structure and function are mediated by variations in soil physical and chemical properties

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    Forest structure and dynamics have been noted to vary across the Amazon Basin in an east-west gradient in a pattern which coincides with variations in soil fertility and geology. This has resulted in the hypothesis that soil fertility may play an important role in explaining Basin-wide variations in forest biomass, growth and stem turnover rates. To test this hypothesis and assess the importance of edaphic properties in affect forest structure and dynamics, soil and plant samples were collected in a total of 59 different forest plots across the Amazon Basin. Samples were analysed for exchangeable cations, C, N, pH with various Pfractions also determined. Physical properties were also examined and an index of soil physical quality developed. Overall, forest structure and dynamics were found to be strongly and quantitatively related to edaphic conditions. Tree turnover rates emerged to be mostly influenced by soil physical properties whereas forest growth rates were mainly related to a measure of available soil phosphorus, although also dependent on rainfall amount and distribution. On the other hand, large scale variations in forest biomass could not be explained by any of the edaphic properties measured, nor by variation in climate. A new hypothesis of self-maintaining forest dynamic feedback mechanisms initiated by edaphic conditions is proposed. It is further suggested that this is a major factor determining forest disturbance levels, species composition and forest productivity on a Basin wide scale

    Women's experience of intrapartum transfer from a Western Australian birth centre co-located to a tertiary maternity hospital

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    Š 2016 Kuliukas et al. Background: The aim of this Western Australian study was to describe the overall labour and birth experience of women who were transferred during the first and second stages of labour from a low risk woman-centred, midwifery-led birth centre to a co-located tertiary maternity referral hospital. Methods: Using a descriptive phenomenological design, fifteen women were interviewed up to 8weeks post birth (July to October, 2013) to explore their experience of the intrapartum transfer. Giorgi's method of analysis was used. Results: The following themes and subthemes emerged: 1) The midwife's voice with subthemes, a) The calming effect and b) Speaking up on my behalf; 2) In the zone with subthemes, a) Hanging in there and b) Post birth rationalizing; 3) Best of both worlds with subthemes a) The feeling of relief on transfer to tertiary birth suite and b) Returning back to the comfort and familiarity of the birth centre; 4) Lost sense of self; and 5) Lost birth dream with subthemes a) Narrowing of options and b) Feeling of panic. Women found the midwife's voice guided them through the transfer experience and were appreciative of continuity of care. There was a sense of disruption to expectations and disappointment in not achieving the labour and birth they had anticipated. There was however appreciation that the referral facility was nearby and experts were close at hand. The focus of care altered from woman to fetus, making women feel diminished. Women were glad to return to the familiar birth centre after the birth with the opportunity to talk through and fully understand their labour journey which helped them contextualise the transfer as one part of the whole experience. Conclusions: Findings can inform midwives of the value of a continuity of care model within a birth centre, allowing women both familiarity and peace of mind. Maternity care providers should ensure that the woman remains the focus of care after transfer and understand the significance of effective communication to ensure women are included in all care discussions

    Pain relief in labour: a qualitative study to determine how to support women to make decisions about pain relief in labour

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    Background Engagement in decision making is a key priority of modern healthcare. Women are encouraged to make decisions about pain relief in labour in the ante-natal period based upon their expectations of what labour pain will be like. Many women find this planning difficult. The aim of this qualitative study was to explore how women can be better supported in preparing for, and making, decisions during pregnancy and labour regarding pain management. Methods Semi-structured interviews were conducted with 13 primiparous and 10 multiparous women at 36 weeks of pregnancy and again within six weeks postnatally. Data collection and analysis occurred concurrently to identify key themes. Results Three main themes emerged from the data. Firstly, during pregnancy women expressed a degree of uncertainty about the level of pain they would experience in labour and the effect of different methods of pain relief. Secondly, women reflected on how decisions had been made regarding pain management in labour and the degree to which they had felt comfortable making these decisions. Finally, women discussed their perceived levels of control, both desired and experienced, over both their bodies and the decisions they were making. Conclusion This study suggests that the current approach of antenatal preparation in the NHS, of asking women to make decisions antenatally for pain relief in labour, needs reviewing. It would be more beneficial to concentrate efforts on better informing women and on engaging them in discussions around their values, expectations and preferences and how these affect each specific choice rather than expecting them to make to make firm decisions in advance of such an unpredictable event as labour

    Association between perineal trauma and pain in primiparous women

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    Objective To identify the association between perineal trauma and pain in 473 primiparous women. Method Cross-sectional study in which pain was measured by the numerical pain scale (0 to 10 - 0 being no pain and 10 maximal pain). Results The prevalence and mean intensity of pain were 33.0% and 4.7 points (standard deviation = 2.0) in the numeric scale, respectively. Episiotomy represented the most frequent trauma (46.7%). The occurrence and intensity of the pain were associated with perineal trauma and postpartum time. Having perineal trauma tripled the chance of pain. Each hour elapsed following the birth reduced the chance of pain by 4.8%. Conclusion Primiparous women are subject to a high frequency of perineal trauma, with episiotomy being the most prominent. Perineal pain affects approximately one-third of primiparous women and is associated with the postpartum time and perineal traumas

    Getting more than they realized they needed: a qualitative study of women's experience of group prenatal care

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    <p>Abstract</p> <p>Background</p> <p>Pregnant women in Canada have traditionally received prenatal care individually from their physicians, with some women attending prenatal education classes. Group prenatal care is a departure from these practices providing a forum for women to experience medical care and child birth education simultaneously and in a group setting. Although other qualitative studies have described the experience of group prenatal care, this is the first which sought to understand the central meaning or core of the experience. The purpose of this study was to understand the central meaning of the experience of group prenatal care for women who participated in CenteringPregnancy through a maternity clinic in Calgary, Canada.</p> <p>Methods</p> <p>The study used a phenomenological approach. Twelve women participated postpartum in a one-on-one interview and/or a group validation session between June 2009 and July 2010.</p> <p>Results</p> <p>Six themes emerged: (1) "getting more in one place at one time"; (2) "feeling supported"; (3) "learning and gaining meaningful information"; (4) "not feeling alone in the experience"; (5) "connecting"; and (6) "actively participating and taking on ownership of care". These themes contributed to the core phenomenon of women "getting more than they realized they needed". The active sharing among those in the group allowed women to have both their known and subconscious needs met.</p> <p>Conclusions</p> <p>Women's experience of group prenatal care reflected strong elements of social support in that women had different types of needs met and felt supported. The findings also broadened the understanding of some aspects of social support beyond current theories. In a contemporary North American society, the results of this study indicate that women gain from group prenatal care in terms of empowerment, efficiency, social support and education in ways not routinely available through individual care. This model of care could play a key role in addressing women's needs and improving health outcomes.</p
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