36 research outputs found

    Abiotic conditions in cephalopod (Sepia officinalis) eggs: embryonic development at low pH and high pCO2

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    Low pO(2) values have been measured in the perivitelline fluids (PVF) of marine animal eggs on several occasions, especially towards the end of development, when embryonic oxygen consumption is at its peak and the egg case acts as a massive barrier to diffusion. Several authors have therefore suggested that oxygen availability is the key factor leading to hatching. However, there have been no measurements of PVF pCO(2) so far. This is surprising, as elevated pCO(2) could also constitute a major abiotic stressor for the developing embryo. As a first attempt to fill this gap in knowledge, we measured pO(2), pCO(2) and pH in the PVF of late cephalopod (Sepia officinalis) eggs. We found linear relationships between embryo wet mass and pO(2), pCO(2) and pH. pO(2) declined from > 12 kPa to less than 5 kPa, while pCO(2) increased from 0.13 to 0.41 kPa. In the absence of active accumulation of bicarbonate in the PVF, pH decreased from 7.7 to 7.2. Our study supports the idea that oxygen becomes limiting in cephalopod eggs towards the end of development; however, pCO(2) and pH shift to levels that have caused significant physiological disturbances in other marine ectothermic animals. Future research needs to address the physiological adaptations that enable the embryo to cope with the adverse abiotic conditions in their egg environment

    Extending conceptual understanding : how interprofessional education influences affective domain development

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    Background: Interprofessional learning (IPL) can influence affective domain development of students, through teaching activities that facilitate learning with, from and about other professions. Current quantitative evidence offers limited explanation of how this learning is achieved within IPL programmes. This original paper tests a conceptual framework drawn from theories on IPL and affective domain development (attitudes, values and behaviours) to explain what works for whom, when and in what circumstances. Methods: The objectives of the study were twofold: to evaluate the impact of the IPL programme on the student’s attitudes and values, and identify behaviour changes in clinical practice towards interprofessional working. Using an action research approach, based in practice, an IPL programme was delivered over six weeks. Students from five professional disciplines: nursing, radiography, physiotherapy, social work, and podiatry (n=63) participated over the two action research cycles and in semi structured focus groups (n=37). Results: The recorded personal experiences of the IPL activities on the students were examined in relation to the: type of activity; impact on the affective domain of learning (attitude, value, or behaviour) and self-reported outcome on application to their practice. Modification in affective domain development was measured to identification or internalisation stage for 30 of the students. Self-reported outcomes on application to practice included direct impact on patient care, personal resilience building, improved communication and ability to challenge practice. Conclusion: This paper presents a conceptual framework not evident in current research, in regards to what IPL works for whom, in what circumstances and when. IPL Activities that address a personal reward or incentive and are delivered over 4 weeks, imitating ‘circles of care,’ that explore self-assessment, team building and reflection can lead to sustained change in values, attitudes and behaviours. Keywords: Action Research, Interprofessional Education, Interprofessional learning, Health and Social care, Collaboration

    Interaction between MHD Generator and dc-ac Power Conversion System

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    Connectivity of Ephemeral and Intermittent Streams in a Subtropical Atlantic Forest Headwater Catchment

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    Stream network extension and contraction depend on landscape features and the characteristics of precipitation events. Although this dependency is widely recognized, the interaction among overland-flow generation processes, drainage active length, and frequency in temporary streams remains less understood. We studied a forest headwater catchment with wide variation in soil depth to investigate the runoff generation processes that lead to the occurrence of ephemeral and intermittent flow and connectivity between hillslope and outlet. We used low-cost equipment to monitor the variation in the length of the active drainage network and to measure the water table development. The flow in the channels can develop even under light rainfall conditions, while the connectivity is controlled by antecedent wetness, total precipitation, and active contribution area thresholds. Runoff permanence and fragmentation were related to soil depth variation; flow being usually more disconnected due to deeper water tables in deeper soil locations. Our findings emphasized the impact of soil structure on runoff generation in hillslopes and can be useful in the management of the most active areas and their impact on the quality of available water

    A new fetal RHD genotyping test : costs and benefits of mass testing to target antenatal anti-D prophylaxis in England and Wales

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    Background Postnatal and antenatal anti-D prophylaxis have dramatically reduced maternal sensitisations and cases of rhesus disease in babies born to women with RhD negative blood group. Recent scientific advances mean that non-invasive prenatal diagnosis (NIPD), based on the presence of cell-free fetal DNA in maternal plasma, could be used to target prophylaxis on "at risk" pregnancies where the fetus is RhD positive. This paper provides the first assessment of cost-effectiveness of NIPD-targeted prophylaxis compared to current policies. Methods We conducted an economic analysis of NIPD implementation in England and Wales. Two scenarios were considered. Scenario 1 assumed that NIPD will be only used to target antenatal prophylaxis with serology tests continuing to direct post-delivery prophylaxis. In Scenario 2, NIPD would also displace postnatal serology testing if an RhD negative fetus was identified. Costs were estimated from the provider's perspective for both scenarios together with a threshold royalty fee per test. Incremental costs were compared with clinical implications. Results The basic cost of an NIPD in-house test is ÂŁ16.25 per sample (excluding royalty fee). The two-dose antenatal prophylaxis policy recommended by NICE is estimated to cost the NHS ÂŁ3.37 million each year. The estimated threshold royalty fee is ÂŁ2.18 and ÂŁ8.83 for Scenarios 1 and 2 respectively. At a ÂŁ2.00 royalty fee, mass NIPD testing would produce no saving for Scenario 1 and ÂŁ507,154 per annum for Scenario 2. Incremental cost-effectiveness analysis indicates that, at a test sensitivity of 99.7% and this royalty fee, NIPD testing in Scenario 2 will generate one additional sensitisation for every ÂŁ9,190 saved. If a single-dose prophylaxis policy were implemented nationally, as recently recommended by NICE, Scenario 2 savings would fall. Conclusions Currently, NIPD testing to target anti-D prophylaxis is unlikely to be sufficiently cost-effective to warrant its large scale introduction in England and Wales. Only minor savings are calculated and, balanced against this, the predicted increase in maternal sensitisations may be unacceptably high. Reliability of NIPD assays still needs to be demonstrated rigorously in different ethnic minority populations. First trimester testing is unlikely to alter this picture significantly although other emerging technologies may
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