846 research outputs found

    Quantitative measure of evolution of bright cluster galaxies at moderate redshifts

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    Using archival data from the Hubble Space Telescope, we study the quantitative morphological evolution of spectroscopically confirmed bright galaxies in the core regions of nine clusters ranging in redshift from z=0.31z = 0.31 to z=0.84z = 0.84. We use morphological parameters derived from two dimensional bulge-disk decomposition to study the evolution. We find an increase in the mean bulge-to-total luminosity ratio B/TB/T as the Universe evolves. We also find a corresponding increase in the fraction of early type galaxies and in the mean S\'ersic index. We discuss these results and their implications to physical mechanisms for evolution of galaxy morphology.Comment: 5 pages, 3 figures, Accepted for publication in MNRAS: Letter

    Bmf upregulation through the AMP-activated protein kinase pathway may protect the brain from seizure-induced cell death.

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    Prolonged seizures (status epilepticus, SE) can cause neuronal death within brain regions such as the hippocampus. This may contribute to impairments in cognitive functioning and trigger or exacerbate epilepsy. Seizure-induced neuronal death is mediated, at least in part, by apoptosis-associated signaling pathways. Indeed, mice lacking certain members of the potently proapoptotic BH3-only subfamily of Bcl-2 proteins are protected against hippocampal damage caused by status epilepticus. The recently identified BH3-only protein Bcl-2-modifying factor (Bmf) normally interacts with the cytoskeleton, but upon certain cellular stresses, such as loss of extracellular matrix adhesion or energy crisis, Bmf relocalizes to mitochondria, where it can promote Bax activation and mitochondrial dysfunction. Although Bmf has been widely reported in the hematopoietic system to exert a proapoptotic effect, no studies have been undertaken in models of neurological disorders. To examine whether Bmf is important for seizure-induced neuronal death, we studied Bmf induction after prolonged seizures induced by intra-amygdala kainic acid (KA) in mice, and examined the effect of Bmf-deficiency on seizures and damage caused by SE. Seizures triggered an early (1-8 h) transcriptional activation and accumulation of Bax in the cell death-susceptible hippocampal CA3 subfield. Bmf mRNA was biphasically upregulated beginning at 1 h after SE and returning to normal by 8 h, while again being found elevated in the hippocampus of epileptic mice. Bmf upregulation was prevented by Compound C, an inhibitor of adenosine monophosphate-activated protein kinase, indicating Bmf expression may be induced in response to bioenergetic stress. Bmf-deficient mice showed normal sensitivity to the convulsant effects of KA, but, surprisingly, displayed significantly more neuronal death in the hippocampal CA1 and CA3 subfields after SE. These are the first studies investigating Bmf in a model of neurologic injury, and suggest that Bmf may protect neurons against seizure-induced neuronal death in vivo

    Good practice in social care: the views of people with severe and complex needs and those who support them

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    This paper reports findings drawn from a study of good practice in English social care for adults with disability and older people with severe and complex needs. People with severe and complex needs are a relatively small proportion of adult social care service users, but they are growing in numbers and have resource-intensive needs. The study involved qualitative research with adults with disability and older people with severe and complex needs, family carers and members of specialist organisations (n = 67), focusing on the features of social care services they considered to be good practice. Data were collected between August 2010 and June 2011. The approach to data collection was flexible, to accommodate participants' communication needs and preferences, including face-to-face and telephone interviews, Talking Mats(c) sessions and a focus group. Data were managed using Framework and analysed thematically. Features of good practice were considered at three levels: (i) everyday support, (ii) service organisation, and (iii) commissioning. Findings relating to the first two of these are presented here. Participants emphasised the importance of person-centred ways of working at all levels. Personalisation, as currently implemented in English social care, aims to shift power from professionals to service users through the allocation of personal budgets. This approach focuses very much on the role of the individual in directing his/her own support arrangements. However, participants in this study also stressed the importance of ongoing professional support, for example, from a specialist key worker or case manager to co-ordinate diverse services and ensure good practice at an organisational level. The paper argues that, despite the recent move to shift power from professionals to service users, people with the most complex needs still value support from professionals and appropriate organisational support. Without these, they risk being excluded from the benefits that personalisation, properly supported, could yield. Keywords : continuity of care; dementia; people with disability; qualitative research; service delivery and organisation

    Socioeconomic Position and DNA Methylation Age Acceleration across the Lifecourse.

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    Accelerated DNA methylation age is linked to all-cause mortality and environmental factors, but studies of associations with socioeconomic position are limited. Studies generally use small selected samples, and it is unclear how findings with two commonly used methylation age calculations (Horvath and Hannum) translate to general population samples including younger and older adults. In 1099 UK adults aged 28-98 y in 2011-12, we assessed the relationship of Horvath and Hannum DNA methylation age acceleration with a range of social position measures: current income and employment, education, income and unemployment across a 12-year period, and childhood social class. Accounting for confounders, participants less advantaged in childhood were epigenetically 'older' as adults: compared to participants with professional/managerial parents, Hannum age was 1.07 years higher (95% confidence interval (CI):0.20-1.94) for those with parents in semi-skilled/unskilled occupations, and 1.85 years higher (95%CI:0.67-3.02) for participants without a working parent at age 14. No other robust associations were seen. Results accord with research implicating early life circumstances as critical for DNA methylation age in adulthood. Since methylation age acceleration as measured by the Horvath and Hannum estimators appears strongly linked to chronological age, research examining associations with the social environment must take steps to avoid age-related confounding

    Defending the genome from the enemy within:mechanisms of retrotransposon suppression in the mouse germline

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    The viability of any species requires that the genome is kept stable as it is transmitted from generation to generation by the germ cells. One of the challenges to transgenerational genome stability is the potential mutagenic activity of transposable genetic elements, particularly retrotransposons. There are many different types of retrotransposon in mammalian genomes, and these target different points in germline development to amplify and integrate into new genomic locations. Germ cells, and their pluripotent developmental precursors, have evolved a variety of genome defence mechanisms that suppress retrotransposon activity and maintain genome stability across the generations. Here, we review recent advances in understanding how retrotransposon activity is suppressed in the mammalian germline, how genes involved in germline genome defence mechanisms are regulated, and the consequences of mutating these genome defence genes for the developing germline

    Cluster Lenses

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    Clusters of galaxies are the most recently assembled, massive, bound structures in the Universe. As predicted by General Relativity, given their masses, clusters strongly deform space-time in their vicinity. Clusters act as some of the most powerful gravitational lenses in the Universe. Light rays traversing through clusters from distant sources are hence deflected, and the resulting images of these distant objects therefore appear distorted and magnified. Lensing by clusters occurs in two regimes, each with unique observational signatures. The strong lensing regime is characterized by effects readily seen by eye, namely, the production of giant arcs, multiple-images, and arclets. The weak lensing regime is characterized by small deformations in the shapes of background galaxies only detectable statistically. Cluster lenses have been exploited successfully to address several important current questions in cosmology: (i) the study of the lens(es) - understanding cluster mass distributions and issues pertaining to cluster formation and evolution, as well as constraining the nature of dark matter; (ii) the study of the lensed objects - probing the properties of the background lensed galaxy population - which is statistically at higher redshifts and of lower intrinsic luminosity thus enabling the probing of galaxy formation at the earliest times right up to the Dark Ages; and (iii) the study of the geometry of the Universe - as the strength of lensing depends on the ratios of angular diameter distances between the lens, source and observer, lens deflections are sensitive to the value of cosmological parameters and offer a powerful geometric tool to probe Dark Energy. In this review, we present the basics of cluster lensing and provide a current status report of the field.Comment: About 120 pages - Published in Open Access at: http://www.springerlink.com/content/j183018170485723/ . arXiv admin note: text overlap with arXiv:astro-ph/0504478 and arXiv:1003.3674 by other author

    Environmental differences between sites control the diet and nutrition of the carnivorous plant Drosera rotundifolia

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    Background and aims: Carnivorous plants are sensitive to small changes in resource availability, but few previous studies have examined how differences in nutrient and prey availability affect investment in and the benefit of carnivory. We studied the impact of site-level differences in resource availability on ecophysiological traits of carnivory for Drosera rotundifolia L. Methods: We measured prey availability, investment in carnivory (leaf stickiness), prey capture and diet of plants growing in two bogs with differences in N deposition and plant available N: Cors Fochno (0.62 g m−2 yr.−1, 353 μg l−1), Whixall Moss (1.37 g m−2 yr.−1, 1505 μg l−1). The total N amount per plant and the contributions of prey/root N to the plants’ N budget were calculated using a single isotope natural abundance method. Results: Plants at Whixall Moss invested less in carnivory, were less likely to capture prey, and were less reliant on prey-derived N (25.5% compared with 49.4%). Actual prey capture did not differ between sites. Diet composition differed – Cors Fochno plants captured 62% greater proportions of Diptera. Conclusions: Our results show site-level differences in plant diet and nutrition consistent with differences in resource availability. Similarity in actual prey capture may be explained by differences in leaf stickiness and prey abundance

    The uneven geographies of the Olympic carceral : from exceptionalism to normalisation

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    In recent years a vast academic literature has developed around the concept of ‘militarising’ or ‘securitising’ cities and in particular the policy responses to the occurrence of crime, fear of crime and the evaluation of cities as strategic sites for a spectrum of large-scale increasingly destructive perturbations in everyday urban life, such as riots, protest and acts of terrorism. Increasingly policy interventions in response to such threats have embodied characteristics of the ‘carceral archipelago’ where incarceration techniques and strategies are punitively deployed within public places of the city and embedded within the design of urban space. Such attempts at creating increasingly hyper-carceral spaces have often been supported by an array of legislation and regulation targeting the control of particular activities deemed unacceptable or inappropriate. This paper draws conceptually from the urban security literature noted above and emerging studies within the nascent sub-discipline of carceral geography, and examines their convergence on the issue of Olympic security planning. This highlights the various spatial strategies and imprints that emerge from new conceptualisations and practices of securitisation, and how these might be seen to characterise an increasingly punitive state. Here Agamben's studies of exceptionality are deployed to highlight how ‘lockdown’ security often becomes the ‘normal’ option for Olympic cities, seen as being on the frontline in the war on terror, and how a range of uneven geographies emerge and are sustained in such locations before, during and after the event. Empirically the paper uses data from ethnographic research focusing on the experiences of security preparation for, and post-event legacy of, the London 2012 Olympics. The paper also seeks to highlight how lessons from the military-carceral security strategies deployed in London have been transferred to subsequent host cities of Sochi (2014) and Rio de Janeiro (2016)

    The politics of ageing: health consumers, markets and hegemonic challenge

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    In recent years ageing has travelled from the placid backwaters of politics into the mainstream of economic, social and cultural debate. What are the forces that have politicised ageing, creating a sustained opposition to the supply side hegemony of pharmaceuticals, medicine and state which has historically constructed, propagated and legitimised the understanding of ageing as decline in social worth? In addressing this question, the paper develops Gramsci's theory of hegemony to include the potentially disruptive demand side power of consumers and markets. It shows how in the case of ageing individuals acting in concert through the mechanisms of the market, and not institutionalised modes of opposition, may become the agents of hegemonic challenge through a combination of lifecourse choice and electoral leverage. In response, the hegemony is adapting through the promotion of professionally defined interpretations of ‘active ageing’ designed to retain hegemonic control. With the forces of hegemony and counter‐hegemony nicely balanced and fresh issues such as intergenerational justice constantly emerging, the political tensions of ageing are set to continue

    Loss of Function of TET2 Cooperates with Constitutively Active KIT in Murine and Human Models of Mastocytosis

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    Systemic Mastocytosis (SM) is a clonal disease characterized by abnormal accumulation of mast cells in multiple organs. Clinical presentations of the disease vary widely from indolent to aggressive forms, and to the exceedingly rare mast cell leukemia. Current treatment of aggressive SM and mast cell leukemia is unsatisfactory. An imatinib-resistant activating mutation of the receptor tyrosine kinase KIT (KIT D816V) is most frequently present in transformed mast cells and is associated with all clinical forms of the disease. Thus the etiology of the variable clinical aggressiveness of abnormal mast cells in SM is unclear. TET2 appears to be mutated in primary human samples in aggressive types of SM, suggesting a possible role in disease modification. In this report, we demonstrate the cooperation between KIT D816V and loss of function of TET2 in mast cell transformation and demonstrate a more aggressive phenotype in a murine model of SM when both mutations are present in progenitor cells. We exploit these findings to validate a combination treatment strategy targeting the epigenetic deregulation caused by loss of TET2 and the constitutively active KIT receptor for the treatment of patients with aggressive SM
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