1,138 research outputs found

    Effects of abstinence on brain morphology in alcoholism: A MRI study

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    Chronic alcohol abuse leads to morphological changes of the brain. We investigated if these volumetric changes are reversible after a period of abstinence. For this reason 41 male and 15 female alcohol patients underwent MRI-scanning after in-patient detoxification (baseline) entering alcoholism treatment programs, and between 6 and 9 months later (follow-up), in a phase of convalescence. Additionally, 29 male and 16 female control subjects were examined. The MRI-scans were delineated and the resulting regions of interest, volumes of lateral ventricles and prefrontal lobes were expressed relatively to total brain volume. Compared to control subjects alcohol patients showed bilaterally decreased prefrontal lobes (11% reduction) and increased lateral ventricles (up to 42% enlargement). The extent of the ventricular increase was depending on patient’s additional psychiatric diagnosis, showing smaller lateral ventricles in patients with additional personality disorder. While at follow-up the size of prefrontal lobes remained unchanged, volumes of the lateral ventricles decreased (5–6% reduction) in alcohol patients with abstinence and improved drinking behavior, especially in patients that underwent only one detoxification. The extent of the ventricular enlargement correlated with the elevation of alcohol related laboratory measures (mean corpuscular volume, gamma-glutamyl transpeptidase). In conclusion this study confirms the hypothesis that alcoholism causes brain damages that are partially reversible. It should be analyzed in further studies with larger sample sizes, if complete brain regeneration is possible maintaining abstinence over a longer period

    Small donors in world politics: The role of trust funds in the foreign aid policies of Central and Eastern European donors

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    The Central and Eastern European (CEE) EU member states have emerged as new donors of international development assistance since the turn of the millennium. The literature has tended to focus on the bilateral components of these policies, and neglected CEE multilateral aid. This paper contributes to filling this gap by examining how and why CEE donors contribute to trust funds operated by multilateral donors. The aim of the paper is twofold: First, it provides a descriptive account of how CEE countries use trust funds in the allocation of their foreign aid. Second, it explains this allocation using data from qualitative interviews with CEE officials. CEE countries make much less use of trust funds than might be expected. This is due not only to the loss of visibility and control over their resources, but also to how CEE companies and non-governmental organisations (NGOs) rarely achieve funding successes at multilateral organisations

    Cosmology with Gravitational Lensing

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    In these lectures I give an overview of gravitational lensing, concentrating on theoretical aspects, including derivations of some of the important results. Topics covered include the determination of surface mass densities of intervening lenses, as well as the statistical analysis of distortions of galaxy images by general inhomogeneities (cosmic shear), both in 2D projection on the sky, and in 3D where source distance information is available. 3D mass reconstruction and the shear ratio test are also considered, and the sensitivity of observables to Dark Energy is used to show how its equation of state may be determined using weak lensing. Finally, the article considers the prospect of testing Einstein's General Relativity with weak lensing, exploiting the differences in growth rates of perturbations in different models.} \abstract{In these lectures I give an overview of gravitational lensing, concentrating on theoretical aspects, including derivations of some of the important results. Topics covered include the determination of surface mass densities of intervening lenses, as well as the statistical analysis of distortions of galaxy images by general inhomogeneities (cosmic shear), both in 2D projection on the sky, and in 3D where source distance information is available. 3D mass reconstruction and the shear ratio test are also considered, and the sensitivity of observables to Dark Energy is used to show how its equation of state may be determined using weak lensing. Finally, the article considers the prospect of testing Einstein's General Relativity with weak lensing, exploiting the differences in growth rates of perturbations in different models.Comment: Lectures given at Como Summer School 2007, now published (in 'Dark Matter and Dark Energy', 2011, ASSL 370, eds. Matarrese, Colpi, Gorini, Moschella

    Dark matter halo properties of GAMA galaxy groups from 100 square degrees of KiDS weak lensing data

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    The Kilo-Degree Survey (KiDS) is an optical wide-field survey designed to map the matter distribution in the Universe using weak gravitational lensing. In this paper, we use these data to measure the density profiles and masses of a sample of 1400\sim \mathrm{1400} spectroscopically identified galaxy groups and clusters from the Galaxy And Mass Assembly (GAMA) survey. We detect a highly significant signal (signal-to-noise-ratio \sim 120), allowing us to study the properties of dark matter haloes over one and a half order of magnitude in mass, from M10131014.5h1MM \sim 10^{13}-10^{14.5} h^{-1}\mathrm{M_{\odot}}. We interpret the results for various subsamples of groups using a halo model framework which accounts for the mis-centring of the Brightest Cluster Galaxy (used as the tracer of the group centre) with respect to the centre of the group's dark matter halo. We find that the density profiles of the haloes are well described by an NFW profile with concentrations that agree with predictions from numerical simulations. In addition, we constrain scaling relations between the mass and a number of observable group properties. We find that the mass scales with the total r-band luminosity as a power-law with slope 1.16±0.131.16 \pm 0.13 (1-sigma) and with the group velocity dispersion as a power-law with slope 1.89±0.271.89 \pm 0.27 (1-sigma). Finally, we demonstrate the potential of weak lensing studies of groups to discriminate between models of baryonic feedback at group scales by comparing our results with the predictions from the Cosmo-OverWhelmingly Large Simulations (Cosmo-OWLS) project, ruling out models without AGN feedback

    The masses of satellites in GAMA galaxy groups from 100 square degrees of KiDS weak lensing data

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    We use the first 100 sq. deg. of overlap between the Kilo-Degree Survey (KiDS) and the Galaxy And Mass Assembly (GAMA) survey to determine the galaxy halo mass of ~10,000 spectroscopically-confirmed satellite galaxies in massive (M>1013h1MM > 10^{13}h^{-1}{\rm M}_\odot) galaxy groups. Separating the sample as a function of projected distance to the group centre, we jointly model the satellites and their host groups with Navarro-Frenk-White (NFW) density profiles, fully accounting for the data covariance. The probed satellite galaxies in these groups have total masses logMsub/(h1M)11.712.2\log M_{\rm sub} /(h^{-1}{\rm M}_\odot) \approx 11.7 - 12.2 consistent across group-centric distance within the errorbars. Given their typical stellar masses, logM,sat/(h2M)10.5\log M_{\rm \star,sat}/(h^{-2}{\rm M}_\odot) \sim 10.5, such total masses imply stellar mass fractions of M,sat/Msub0.04h1M_{\rm \star,sat} /M_{\rm sub} \approx 0.04 h^{-1} . The average subhalo hosting these satellite galaxies has a mass Msub0.015MhostM_{\rm sub} \sim 0.015M_{\rm host} independent of host halo mass, in broad agreement with the expectations of structure formation in a Λ\LambdaCDM universe

    Residential Radon and Brain Tumour Incidence in a Danish Cohort

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    BACKGROUND: Increased brain tumour incidence over recent decades may reflect improved diagnostic methods and clinical practice, but remain unexplained. Although estimated doses are low a relationship between radon and brain tumours may exist. OBJECTIVE: To investigate the long-term effect of exposure to residential radon on the risk of primary brain tumour in a prospective Danish cohort. METHODS: During 1993-1997 we recruited 57,053 persons. We followed each cohort member for cancer occurrence from enrolment until 31 December 2009, identifying 121 primary brain tumour cases. We traced residential addresses from 1 January 1971 until 31 December 2009 and calculated radon concentrations at each address using information from central databases regarding geology and house construction. Cox proportional hazards models were used to estimate incidence rate-ratios (IRR) and 95% confidence intervals (CI) for the risk of primary brain tumours associated with residential radon exposure with adjustment for age, sex, occupation, fruit and vegetable consumption and traffic-related air pollution. Effect modification by air pollution was assessed. RESULTS: Median estimated radon was 40.5 Bq/m(3). The adjusted IRR for primary brain tumour associated with each 100 Bq/m(3) increment in average residential radon levels was 1.96 (95% CI: 1.07; 3.58) and this was exposure-dependently higher over the four radon exposure quartiles. This association was not modified by air pollution. CONCLUSIONS: We found significant associations and exposure-response patterns between long-term residential radon exposure radon in a general population and risk of primary brain tumours, adding new knowledge to this field. This finding could be chance and needs to be challenged in future studies
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