1,857 research outputs found

    FACS-sorted putative oogonial stem cells from the ovary are neither DDX4-positive nor germ cells

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    Whether the adult mammalian ovary contains oogonial stem cells (OSCs) is controversial. They have been isolated by a live-cell sorting method using the germ cell marker DDX4, which has previously been assumed to be cytoplasmic, not surfacebound. Furthermore their stem cell and germ cell characteristics remain disputed. Here we show that although OSC-like cells can be isolated from the ovary using an antibody to DDX4, there is no good in silico modelling to support the existence of a surfacebound DDX4. Furthermore these cells when isolated were not expressing DDX4, and did not initially possess germline identity. Despite these unremarkable beginnings, they acquired some pre-meiotic markers in culture, including DDX4, but critically never expressed oocyte-specific markers, and furthermore were not immortal but died after a few months. Our results suggest that freshly isolated OSCs are not germ stem cells, and are not being isolated by their DDX4 expression. However it may be that culture induces some pre-meiotic markers. In summary the present study offers weight to the dogma that the adult ovary is populated by a fixed number of oocytes and that adult de novo production is a rare or insignificant event

    'All the world's a stage': Accounting for the dementia experience - insights from the IDEAL study

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    YesQualitative dementia research emphasises the importance of recognising the voice of the person with dementia. However, research imbued with a politics of selfhood, whereby individuals are called upon to give coherence to experience and emotion, jars with representations of dementia as a gradual decline in capacity. Moreover, it reinforces an assumption that there is an essential experience that can be accessed through different methods. Drawing on Atkinson and Silverman, we view the interview not as confessional but rather as an outcome of social interaction. This paper draws on qualitative interviews from the Improving the Experince of Dementia and Enhancing Active Life (IDEAL) study, to focus specifically on the forms of accounting and storytelling of people living with dementia and how these are produced through the course of the interview encounter. Extracts from our interviews highlight key aspects of this interactional process: (a) social conventions and temporality, (b) self presentation and identity work, (c) accounts and wider cultural meanings. To conclude, we suggest that qualitative research with people with dementia requires a reframing of both the interview encounter and interpretive practices.The IDEAL study’ was funded jointly by the Economic and Social Research Council (ESRC) and the National Institute for Health Research (NIHR) through grant ES/L001853/2 ‘Improving the experience of dementia and enhancing active life: living well with dementia

    Rydberg electrometry for optical lattice clocks

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    Electrometry is performed using Rydberg states to evaluate the quadratic Stark shift of the 5s2 1 S0-5s5p 3 P0 clock transition in strontium. By measuring the Stark shift of the highly excited 5s75d 1 D2 state using electromagnetically induced transparency, we characterize the electric field with sufficient precision to provide tight constraints on the systematic shift to the clock transition. Using the theoretically derived, and experimentally verified, polarizability for this Rydberg state, we can measure the residual field with an uncertainty well below 1Vm−1. This resolution allows us to constrain the fractional frequency uncertainty of the quadratic Stark shift of the clock transition to 2×10−20

    Illness representations in caregivers of people with dementia

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    YesIllness representations shape responses to illness experienced by the self or by others. The illness representations held by family members of those with long-term conditions such as dementia influence their understanding of what is happening to the person and how they respond and provide support. The aim of this study is to explore components of illness representations (label, cause, control and timeline) in caregivers of people with dementia. This was an exploratory study; the data reported came from the Memory Impairment and Dementia Awareness Study (MIDAS). Data from semi-structured interviews with 50 caregivers of people with dementia were analysed using content analysis. The majority of caregivers gave accounts that appeared to endorse a medical/diagnostic label, although many used different terms interchangeably. Caregivers differentiated between direct causes and contributory factors, but the predominant explanation was that dementia had a biological cause. Other perceived causes were hereditary factors, ageing, lifestyle, life events and environmental factors. A limited number of caregivers were able to identify things that people with dementia could do to help manage the condition, while others thought nothing could be done. There were varying views about the efficacy of medication. In terms of timeline, there was considerable uncertainty about how dementia would progress over time. The extent of uncertainty about the cause, timeline and controllability of dementia indicated that caregivers need information on these areas. Tailored information and support taking account of caregivers' existing representations may be most beneficial

    Strings at the bottom of the deformed conifold

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    We present solutions of the equations of motion of macroscopic F and D strings extending along the non compact 4D sections of the conifold geometry and winding around the internal directions. The effect of the Goldstone modes associated with the position of the strings on the internal manifold can be seen as a current on the string that prevents it from collapsing and allows the possibility of static 4D loops. Its relevance in recent models of brane inflation is discussed.Comment: 9+1 page
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