280 research outputs found

    Paracrine effects of oocyte secreted factors and stem cell factor on porcine granulosa and theca cells in vitro

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    Oocyte control of granulosa and theca cell function may be mediated by several growth factors via a local feedback loop(s) between these cell types. This study examined both the role of oocyte-secreted factors on granulosa and thecal cells, cultured independently and in co-culture, and the effect of stem cell factor (SCF); a granulosa cell derived peptide that appears to have multiple roles in follicle development. Granulosa and theca cells were isolated from 2–6 mm healthy follicles of mature porcine ovaries and cultured under serum-free conditions, supplemented with: 100 ng/ml LR3 IGF-1, 10 ng/ml insulin, 100 ng/ml testosterone, 0–10 ng/ml SCF, 1 ng/ml FSH (granulosa), 0.01 ng/ml LH (theca) or 1 ng/ml FSH and 0.01 ng/ml LH (co-culture) and with/without oocyte conditioned medium (OCM) or 5 oocytes. Cells were cultured in 96 well plates for 144 h, after which viable cell numbers were determined. Medium was replaced every 48 h and spent medium analysed for steroids. Oocyte secreted factors were shown to stimulate both granulosa cell proliferation (P < 0.001) and oestradiol production (P < 0.001) by granulosa cells throughout culture. In contrast, oocyte secreted factors suppressed granulosa cell progesterone production after both 48 and 144 hours (P < 0.001). Thecal cell numbers were increased by oocyte secreted factors (P = 0.02), together with a suppression in progesterone and androstenedione synthesis after 48 hours (P < 0.001) and after 144 hours (P = 0.02), respectively. Oocyte secreted factors also increased viable cell numbers (P < 0.001) in co-cultures together with suppression of progesterone (P < 0.001) and oestradiol (P < 0.001). In granulosa cell only cultures, SCF increased progesterone production in a dose dependent manner (P < 0.001), whereas progesterone synthesis by theca cells was reduced in a dose dependent manner (P = 0.002). Co-cultured cells demonstrated an increase in progesterone production with increasing SCF dose (P < 0.001) and an increase in oestradiol synthesis at the highest dose of SCF (100 ng/ml). In summary, these findings demonstrate the presence of a co-ordinated paracrine interaction between somatic cells and germ cells, whereby oocyte derived signals interact locally to mediate granulosa and theca cell function. SCF has a role in modulating this local interaction. In conclusion, the oocyte is an effective modulator of granulosa-theca interactions, one role being the inhibition of luteinization

    A Methodology for the Assessment of Climate Change Adaptation Options for Cultural Heritage Sites

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    Cultural sites are particularly important to Indigenous peoples, their identity, cosmology and sociopolitical traditions. The benefits of local control, and a lack of professional resources, necessitate the development of planning tools that support independent Indigenous cultural site adaptation. We devised and tested a methodology for non-heritage professionals to analyse options that address site loss, build site resilience and build local adaptive capacity. Indigenous rangers from Kakadu National Park and the Djelk Indigenous Protected Area, Arnhem Land, Australia, were engaged as fellow researchers via a participatory action research methodology. Rangers rejected coastal defences and relocating sites, instead prioritising routine use of a risk field survey, documentation of vulnerable sites using new digital technologies and widely communicating the climate change vulnerability of sites via a video documentary. Results support the view that rigorous approaches to cultural site adaptation can be employed independently by local Indigenous stakeholders

    Improving risk prediction model quality in the critically ill:data linkage study

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    Background: A previous National Institute for Health and Care Research study [Harrison DA, Ferrando-Vivas P, Shahin J, Rowan KM. Ensuring comparisons of health-care providers are fair: development and validation of risk prediction models for critically ill patients. Health Serv Deliv Res 2015;3(41)] identified the need for more research to understand risk factors and consequences of critical care and subsequent outcomes. Objectives: First, to improve risk models for adult general critical care by developing models for mortality at fixed time points and time-to-event outcomes, end-stage renal disease, type 2 diabetes, health-care utilisation and costs. Second, to improve risk models for cardiothoracic critical care by enhancing risk factor data and developing models for longer-term mortality. Third, to improve risk models for in-hospital cardiac arrest by enhancing risk factor data and developing models for longer-term mortality and critical care utilisation. Design: Risk modelling study linking existing data. Setting: NHS adult critical care units and acute hospitals in England. Participants: Patients admitted to an adult critical care unit or experiencing an in-hospital cardiac arrest. Interventions: None. Main outcome measures: Mortality at hospital discharge, 30 days, 90 days and 1 year following critical care unit admission; mortality at 1 year following discharge from acute hospital; new diagnosis of end-stage renal disease or type 2 diabetes; hospital resource use and costs; return of spontaneous circulation sustained for > 20 minutes; survival to hospital discharge and 1 year; and length of stay in critical care following in-hospital cardiac arrest. Data sources: Case Mix Programme, National Cardiac Arrest Audit, UK Renal Registry, National Diabetes Audit, National Adult Cardiac Surgery Audit, Hospital Episode Statistics and Office for National Statistics. Results: Data were linked for 965,576 critical care admissions between 1 April 2009 and 31 March 2016, and 83,939 in-hospital cardiac arrests between 1 April 2011 and 31 March 2016. For admissions to adult critical care units, models for 30-day mortality had similar predictors and performance to those for hospital mortality and did not reduce heterogeneity. Models for longer-term outcomes reflected increasing importance of chronic over acute predictors. New models for end-stage renal disease and diabetes will allow benchmarking of critical care units against these important outcomes and identification of patients requiring enhanced follow-up. The strongest predictors of health-care costs were prior hospitalisation, prior dependency and chronic conditions. Adding pre- and intra-operative risk factors to models for cardiothoracic critical care gave little improvement in performance. Adding comorbidities to models for in-hospital cardiac arrest provided modest improvements but were of greater importance for longer-term outcomes. Limitations: Delays in obtaining linked data resulted in the data used being 5 years old at the point of publication: models will already require recalibration. Conclusions: Data linkage provided enhancements to the risk models underpinning national clinical audits in the form of additional predictors and novel outcomes measures. The new models developed in this report may assist in providing objective estimates of potential outcomes to patients and their families. Future work: (1) Develop and test care pathways for recovery following critical illness targeted at those with the greatest need; (2) explore other relevant data sources for longer-term outcomes; (3) widen data linkage for resource use and costs to primary care, outpatient and emergency department data

    Capturing cropland and grassland management impacts on soil carbon in the UK LULUCF inventory

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    This project aimed to identify the extent to which emissions due to changes in Soil Organic Carbon (SOC) stocks arising from Cropland and Grassland/Grazing Land management can be incorporated into the UK’s Land Use, Land Use Change and Forestry (LULUCF) inventory. Key management activities were identified which might affect SOC stocks. A literature review carried out as part of the project concluded that tillage reduction cannot be considered a reliable management option to increase the SOC content of UK soils. However increasing crop residue returns and increasing inputs of manure and fertiliser could increase SOC stock although the SOC stock increases resulting from manure and fertiliser inputs could be outweighed by increases nitrous oxide emissions and the risk of nitrate run-off. The review found that increasing crop yields through increased fertilisation and improved crop rotation could increase the annual input of crop residues and root exudate to soils and hence increase SOC on low fertility soils. Manure additions resulted in greater C sequestration than the addition of equivalent amounts of N as mineral fertiliser and the effect lasted longer. However, increasing inputs of nitrogen from fertiliser or manure risk increasing N2O emissions which could negate any increases in SOC stock. IPCC default stock change factors were judged to be inappropriate to the UK, based on expert opinion and the literature review findings. Therefore the project used the Daily DayCent and Landscape DNDC models to attempt to estimate stock change factors for Cropland management activities under UK conditions. Although based on a very limited dataset this suggested that the effect of Cropland management activities under UK conditions might be less than implied by the IPCC stock change factors. Tillage reduction was found to have little effect on SOC stocks. Increasing manure and crop residue inputs increased SOC stocks, with manure inputs being particularly effective. A framework for reporting SOC stock changes resulting from Cropland management was developed, and used to assess mitigation options. Overall the impact of Cropland Management on SOC is likely to be very small compared to other activities in the LULUCF inventory such as land use change. The most effective mitigation option was using Cropland from annual tillage crops to perennial crops, fallow and set aside. However given the need for food production there is limited scope for such change. Increasing manure, fertiliser and crop residue inputs gave smaller increases in SOC stocks, but practical considerations limit the scope of these actions. Lack of field data on the effect of Grassland improvement on SOC stocks was identified as a knowledge gap. The literature review suggested that intensification could increase SOC stocks under pasture on mineral soils. However, expert opinion suggested that this might not be the case for rough grazing on organo-mineral soils, where intensification might lead to SOC loss. This lack of data meant that it was not possible to calibrate or validate models to estimate UK specific stock change factors for Grassland. As the IPCC stock change factors were judged to be inappropriate to UK conditions assessment of the mitigation potential of Grassland management using these factors was not carried out to avoid presenting potentially misleading results. Suggested strategies for filling these knowledge gaps are outlined in the report. Attempts to assess grass/crop rotation patterns across the UK using data from the Integrated Administration and Control System (IACS) used to handle Common Agricultural Policy (CAP) payments were hampered by difficulties in obtaining access to the data. However land use change matrices were generated for England and Wales, and used to map areas of change. Subject to data availability, this approach could be used in future inventories to give a better representation the effect of rotation patterns on SOC stocks

    Learning to Teach About Ideas and Evidence in Science : The Student Teacher as Change Agent

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    A collaborative curriculum development project was set up to address the lack of good examples of teaching about ideas and evidence and the nature of science encountered by student teachers training to teach in the age range 11-16 in schools in England. Student and teacher-mentor pairs devised, taught and evaluated novel lessons and approaches. The project design required increasing levels of critique through cycles of teaching, evaluation and revision of lessons. Data were gathered from interviews and students' reports to assess the impact of the project on student teachers and to what extent any influences survived when they gained their first teaching posts. A significant outcome was the perception of teaching shifting from the delivery of standard lessons in prescribed ways to endeavours demanding creativity and decision-making. Although school-based factors limited newly qualified teachers' chances to use new lessons and approaches and therefore act as change-agents in schools, the ability to critique curriculum materials and the recognition of the need to create space for professional dialogue were durable gains

    Mindlessness Revisited: Sequential Request Techniques Foster Compliance by Draining Self-control Resources

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    The present research extends previous findings suggesting that sequential request techniques, such as the Foot-in-the-Door (FITD) or Door-in-the-Face (DITF) technique, are primarily effective under conditions conducive of mindlessness. We forward that this mindlessness may be the product of the influence technique itself. More specifically, based on the notion of self-control as a limited resource, we hypothesize that actively responding to the initial request-phase of a FITD-compliance gaining procedure drains the target of his/her self-regulatory resources, thus creating the mindlessness so often observed in social influence settings. This resource depletion opens the door for compliance with the target request. The results were in line with these expectations. More specifically, we observed that active responding to an initial request of a FITD technique reduced the availability of self-regulatory resources. This state of resource depletion mediated the effect of the technique on behavioral compliance. In addition, the results of this study ruled out the alternate explanation that the effects were attributable to mood or a general tendency for acquiescence

    Performativity and primary teacher relations

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    A performativity discourse currently pervades teachers' work. It is a discourse that relies on teachers and schools instituting self-disciplinary measures to satisfy newly transparent public accountability and it operates alongside a market discourse. The introduction of the performativity discourse has affected teacher relations at three levels of professional work: with students, colleagues and local advisor/inspectors. Ethnographic research with primary teachers - which focused on their experience of Ofsted inspections in six schools over periods of up to four years - is the source of this paper. The paper argues that a humanist discourse prevalent in teacher relations with students, colleagues and advisor/inspectors has been challenged by a performativity discourse that: distances teachers from students and creates a dependency culture in opposition to previous mutual and intimate relations; creates self disciplining teams that marginalize individuality and stratifies collegial relations in opposition to previous relations where primary teachers sought consensus; and creates subjugatory, contrived and de-personalized relations between local advisors/inspectors in preference to previous partnership relations. The paper concludes that the change in relations is an indicator of fundamental change to social relations but that primary teachers are in a good position to influence the performativity discourse, albeit it a struggle, by reconstituting it through the maintenance of humanist relations
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