177 research outputs found

    Hydrogenation and dehydrogenation of interstellar PAHs: Spectral characteristics and H_2 formation

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    Interstellar matter and star formationLaboratory astrophysics and astrochemistr

    Generation of vortices and observation of Quantum Turbulence in an oscillating Bose-Einstein Condensate

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    We report on the experimental observation of vortex formation and production of tangled vortex distribution in an atomic BEC of Rb-87 atoms submitted to an external oscillatory perturbation. The oscillatory perturbations start by exciting quadrupolar and scissors modes of the condensate. Then regular vortices are observed finally evolving to a vortex tangle configuration. The vortex tangle is a signature of the presence of a turbulent regime in the cloud. We also show that this turbulent cloud has suppression of the aspect ratio inversion typically observed in quantum degenerate bosonic gases during free expansion.Comment: to appear in JLTP - QFS 200

    What can local authorities do to improve the social care-related quality of life of older adults living at home? Evidence from the Adult Social Care Survey

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    Local authorities spend considerable resources on social care at home for older adults. Given the expected growth in the population of older adults and budget cuts on local government, it is important to find efficient ways of maintaining and improving the quality of life of older adults. The ageing in place literature suggests that policies in other functions of local authorities may have a significant role to play. This study aims to examine the associations between social care-related quality of life (SCRQoL) in older adults and three potential policy targets for local authorities: (i) accessibility of information and advice, (ii) design of the home and (iii) accessibility of the local area. We used cross-sectional data from the English national Adult Social Care Survey (ASCS) 2010/2011 on service users aged 65 years and older and living at home (N=29,935). To examine the association between SCRQoL, as measured by the ASCOT, and three single-item questions about accessibility of information, design of the home and accessibility of the local area, we estimate linear and quantile regression models. After adjusting for physical and mental health factors and other confounders our findings indicate that SCRQoL is significantly lower for older adults who find it more difficult to find information and advice, for those who report that their home design is inappropriate for their needs and for those who find it more difficult to get around their local area. In addition, these three variables are as strongly associated with SCRQoL as physical and mental health factors. We conclude that in seeking to find ways to maintain and improve the quality of life of social care users living at home, local authorities could look more broadly across their responsibilities. Further research is required to explore the cost-effectiveness of these options compared to standard social care services

    A human neural crest model reveals the developmental impact of neuroblastoma-associated chromosomal aberrations

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    Early childhood tumours arise from transformed embryonic cells, which often carry large copy number alterations (CNA). However, it remains unclear how CNAs contribute to embryonic tumourigenesis due to a lack of suitable models. Here we employ female human embryonic stem cell (hESC) differentiation and single-cell transcriptome and epigenome analysis to assess the effects of chromosome 17q/1q gains, which are prevalent in the embryonal tumour neuroblastoma (NB). We show that CNAs impair the specification of trunk neural crest (NC) cells and their sympathoadrenal derivatives, the putative cells-of-origin of NB. This effect is exacerbated upon overexpression of MYCN, whose amplification co-occurs with CNAs in NB. Moreover, CNAs potentiate the pro-tumourigenic effects of MYCN and mutant NC cells resemble NB cells in tumours. These changes correlate with a stepwise aberration of developmental transcription factor networks. Together, our results sketch a mechanistic framework for the CNA-driven initiation of embryonal tumours

    Insights into Planet Formation from Debris Disks

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    The Origin, Early Evolution and Predictability of Solar Eruptions

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    Coronal mass ejections (CMEs) were discovered in the early 1970s when space-borne coronagraphs revealed that eruptions of plasma are ejected from the Sun. Today, it is known that the Sun produces eruptive flares, filament eruptions, coronal mass ejections and failed eruptions; all thought to be due to a release of energy stored in the coronal magnetic field during its drastic reconfiguration. This review discusses the observations and physical mechanisms behind this eruptive activity, with a view to making an assessment of the current capability of forecasting these events for space weather risk and impact mitigation. Whilst a wealth of observations exist, and detailed models have been developed, there still exists a need to draw these approaches together. In particular more realistic models are encouraged in order to asses the full range of complexity of the solar atmosphere and the criteria for which an eruption is formed. From the observational side, a more detailed understanding of the role of photospheric flows and reconnection is needed in order to identify the evolutionary path that ultimately means a magnetic structure will erupt
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