105 research outputs found

    The dependence of Galactic outflows on the properties and orientation of zCOSMOS galaxies at z ~ 1

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    We present an analysis of cool outflowing gas around galaxies, traced by MgII absorption lines in the co-added spectra of a sample of 486 zCOSMOS galaxies at 1 < z < 1.5. These galaxies span a range of stellar masses (9.45< log[M*/Msun]<10.7) and star formation rates (0.14 < log [SFR/Msun/yr] < 2.35). We identify the cool outflowing component in the MgII absorption and find that the equivalent width of the outflowing component increases with stellar mass. The outflow equivalent width also increases steadily with the increasing star formation rate of the galaxies. At similar stellar masses the blue galaxies exhibit a significantly higher outflow equivalent width as compared to red galaxies. The outflow equivalent width shows strong effect with star formation surface density ({\Sigma}SFR) of the sample. For the disk galaxies, the outflow equivalent width is higher for the face-on systems as compared to the edge-on ones, indicating that for the disk galaxies, the outflowing gas is primarily bipolar in geometry. Galaxies typically exhibit outflow velocities ranging from -200 km/s to -300 km/s and on average the face-on galaxies exhibit higher outflow velocity as compared to the edge-on ones. Galaxies with irregular morphologies exhibit outflow equivalent width as well as outflow velocities comparable to face on disk galaxies. These galaxies exhibit minimum mass outflow rates > 5-7 Msun/yr and a mass loading factor ({\eta} = dMout/dt /SFR) comparable to the star formation rates of the galaxies.Comment: 12 pages, 14 figures, ApJ submitte

    Revisiting Brain Atrophy and Its Relationship to Disability in Multiple Sclerosis

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    Brain atrophy is a well-accepted imaging biomarker of multiple sclerosis (MS) that partially correlates with both physical disability and cognitive impairment.Based on MRI scans of 60 MS cases and 37 healthy volunteers, we measured the volumes of white matter (WM) lesions, cortical gray matter (GM), cerebral WM, caudate nucleus, putamen, thalamus, ventricles, and brainstem using a validated and completely automated segmentation method. We correlated these volumes with the Expanded Disability Status Scale (EDSS), MS Severity Scale (MSSS), MS Functional Composite (MSFC), and quantitative measures of ankle strength and toe sensation. Normalized volumes of both cortical and subcortical GM structures were abnormally low in the MS group, whereas no abnormality was found in the volume of the cerebral WM. High physical disability was associated with low cerebral WM, thalamus, and brainstem volumes (partial correlation coefficients ~0.3-0.4) but not with low cortical GM volume. Thalamus volumes were inversely correlated with lesion load (r = -0.36, p<0.005).The GM is atrophic in MS. Although lower WM volume is associated with greater disability, as might be expected, WM volume was on average in the normal range. This paradoxical result might be explained by the presence of coexisting pathological processes, such as tissue damage and repair, that cause both atrophy and hypertrophy and that underlie the observed disability

    Whole-scalp EEG mapping of somatosensory evoked potentials in macaque monkeys

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    Whole-scalp EEG mapping of somatosensory evoked potentials in macaque monkeys

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    High-density scalp EEG recordings are widely used to study whole-brain neuronal networks in humans non-invasively. Here, we validate EEG mapping of somatosensory evoked potentials (SSEPs) in macaque monkeys (Macaca fascicularis) for the long-term investigation of large-scale neuronal networks and their reorganisation after lesions requiring a craniotomy. SSEPs were acquired from 33 scalp electrodes in five adult anaesthetized animals after electrical median or tibial nerve stimulation. SSEP scalp potential maps were identified by cluster analysis and identified in individual recordings. A distributed, linear inverse solution was used to estimate the intracortical sources of the scalp potentials. SSEPs were characterised by a sequence of components with unique scalp topographies. Source analysis confirmed that median nerve SSEP component maps were in accordance with the somatotopic organisation of the sensorimotor cortex. Most importantly, SSEP recordings were stable both intra- and interindividually. We aim to apply this method to the study of recovery and reorganisation of large-scale neuronal networks following a focal cortical lesion requiring a craniotomy. As a prerequisite, the present study demonstrated that a 300-mm2 unilateral craniotomy over the sensorimotor cortex necessary to induce a cortical lesion, followed by bone flap repositioning, suture and gap plugging with calcium phosphate cement, did not induce major distortions of the SSEPs. In conclusion, SSEPs can be successfully and reproducibly recorded from high-density EEG caps in macaque monkeys before and after a craniotomy, opening new possibilities for the long-term follow-up of the cortical reorganisation of large-scale networks in macaque monkeys after a cortical lesion

    Polls as public-politic linkage: A comparative analysis of poll use and roles of MPs in parliamentary debate

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    Opinion polls as a linkage mechanism between the public and politics have rarely been examined in a parliamentary context. In our comparative study (Germany, New Zealand, Switzerland and the United Kingdom) we analyse if and how polls are invoked by MPs with different roles in parliamentary debates. Focusing on three theoretical aspects (responsiveness, populism and deliberation), we find that polls are indeed invoked to bring the views of the public into parliamentary debate to some degree, but they are also often used merely to support policies already developed in the political realm. Fears of the populist effect of polls are exaggerated; polls, in fact, have a positive influence on the discursive quality of parliament. Looking at parliamentary roles, we find very different patterns of poll use: while MPs oriented towards their constituencies use polls in the most direct and participatory vein, others mediate public opinion as displayed by polls through different institutions (the party, the parliament) or through expertise

    Investigating training, transfer and viewpoint effects resulting from recurrent CBT of X-Ray image interpretation

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    X-ray screening of passenger bags is an essential task at airport security checkpoints. In this study we investigated how well airport security screeners can detect guns, knives, improvised explosive devices (IEDs) and other threat objects in X-ray images of passenger bags before and after 3 and 6 months of recurrent (about 20 min per week) computer-based training (CBT). Two experiments conducted at different airports gave very similar results. Training with X-ray Tutor (XRT), an individually adaptive CBT, resulted in large performance increases, especially for detecting IEDs. While performance for detecting IEDs was initially substantially lower than for guns, IEDs could be detected as well as guns after several months of training. A large transfer effect was observed as well: Training with XRT helped screeners recognize new threat objects that were similar in shape as the trained objects. Threat recognition was dependent on the rotation of the objects. If depicted from an unusual viewpoint, prohibited items were more difficult to recognize. The results were compared to two conventional (not adaptive) CBT systems. For one system no training and transfer effects were observed whereas small training and transfer effects were found for the other conventional CBT system

    Public Relations als Medienarbeit

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