400 research outputs found

    Social ontologies online

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    It is commonly said that “there are” social structures on the Internet. But how can they exist there, how can we identify and classify them? A theoretical and methodological framework is presented that describes the relationship between data structures, algorithms, and different types of social structures. We suggest that the latter are “represented” online in different senses of the word: They are not only described, but, by manipulating data, social structures can also be constituted and modified. We then outline a methodology for the analysis of social structures on the Internet: By analyzing the practical meaning of the structures of Internet platforms, we can reconstruct their providers’ and users’ ontological commitments (i.e., what kinds of social structures they have to assume “there are”)

    Differentielle Expressionsmuster von MMP-2, MMP-9 und PCNA in verschiedenen Endometriosestadien und Endometriumkarzinomen

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    In der BRD ist die Endometriose eine hÀufige und durch ihre möglichen Symptome und Folgen eine wichtige Erkrankung. Untersucht wurde die ProliferationsaktivitÀt von Darmendometriose im Vergleich zur Peritonealendometriose und zum Endometriumkarzinom anhand der Expression von MMP-2, MMP-9 und PCNA. Es zeigt sich, dass es Unterschiede im Expressionsverhalten der verschiedenen AntikörperfÀrbungen gibt. MMP-2 und PCNA sind vermehrt in der Darmendometriose im Vergleich zur Peritonealendometriose zu finden. Verglichen zum gut differenzierten Endometriumkarzinom erweist sich die Darmendometriose als stÀrker proliferierendes Gewebe. Mit der höchsten MMP 2 und MMP-9 Expression der drei Gewebearten bestÀtigt sich jedoch die Annahme, dass ein malignes Geschehen noch aggressiver und infiltrativer ist, als die Endometriose. Zum besseren VerstÀndnis der Pathogenese der Endometriose und die sich hieraus mögliche Entwicklung einer individuelleren Therapie können die Ergebnisse einen Beitrag leisten

    Life events and life satisfaction: Estimating effects of multiple life events in combined models

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    How do life events affect life satisfaction? Previous studies focused on a single event or separate analyses of several events. However, life events are often grouped non-randomly over the lifespan, occur in close succession, and are causally linked, raising the question of how to best analyze them jointly. Here, we used representative German data (SOEP; N = 40,121 individuals; n = 41,402 event occurrences) to contrast three fixed-effects model specifications: First, individual event models in which other events were ignored, which are thus prone to undercontrol bias; second, combined event models which controlled for all events, including subsequent ones, which may induce overcontrol bias; and third, our favored combined models that only controlled for preceding events. In this preferred model, the events of new partner, cohabitation, marriage, and childbirth had positive effects on life satisfaction, while separation, unemployment, and death of partner or child had negative effects. Model specification made little difference for employment- and bereavement-related events. However, for events related to romantic relationships and childbearing, small but consistent differences arose between models. Thus, when estimating effects of new partners, separation, cohabitation, marriage, and childbirth, care should be taken to include appropriate controls (and omit inappropriate ones) to minimize bias

    Shell Disease Syndrome Is Associated with Reduced and Shifted Epibacterial Diversity on the Carapace of the Crustacean Cancer pagurus

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    Crustaceans increasingly suffer from the black spot shell disease syndrome, which principally results from bacterial breakdown of their chitinous exoskeleton. Since Cancer pagurus is highly susceptible to this disease, we compared the bacterial communities of black spot affected and non-affected areas of the carapace by amplicon sequencing of 16S rRNA genes and 16S rRNA. Within each spot, bacterial communities of affected areas were less diverse compared to communities from non-affected areas. Communities of different affected spots were, however, more divergent from each other, compared to those of different nonaffected areas. This indicates a reduced and shifted microbial community composition caused by the black spot disease. Different communities found in black spots likely indicate different stages of the disease. In affected areas, Flavobacteriaceae rose up to one of the most abundant and active families, due to massive increase of Aquimarina spp., suggesting a significant role in shell disease syndrome. We isolated 75 bacterial strains from diseased and healthy areas, which primarily affiliated with Proteobacteria and Bacteroidetes, thus reflecting the dominant phyla detected by amplicon sequencing. The ability to degrade chitin was mainly found for Gammaproteobacteria and Aquimarina spp. within the Flavobacteriia, while the ability to use N-acetylglucosamine, the monomer of the polysaccharide chitin, was observed for most isolates, including many Alphaproteobacteria. Furthermore, one third of the isolates showed antagonistic properties. The combination of bacterial community analysis and the physiological properties of the isolates provides insights into a functional complex epibacterial community on the carapace of C. pagurus. Importance In recent years, the shell disease syndrome was detected for several ecologically and economically important crustacean species. Large proportions of populations are affected, e.g., >60% of the widely distributed species Cancer pagurus in different North Sea areas. Bacteria play a significant role in the development of different forms of shell disease, all characterized by microbial chitinolytic degradation of the outer shell. By comparing the bacterial communities of healthy and diseased areas of the shell of C. pagurus we could demonstrate that the disease causes a reduced bacterial diversity within affected areas, a phenomenon co-occurring also with many other diseases. Furthermore, the community composition dramatically changed, with some taxa rising to high relative abundances and showing increased activity, indicating a strong participation in shell disease. Characterization of bacterial isolates obtained from affected and non-affected spots provided deeper insights in their physiological properties and thus the possible role within the microbiome

    Self-Assessment of Individual Differences in Language Switching

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    Language switching is omnipresent in bilingual individuals. In fact, the ability to switch languages (code switching) is a very fast, efficient, and flexible process that seems to be a fundamental aspect of bilingual language processing. In this study, we aimed to characterize psychometrically self-perceived individual differences in language switching and to create a reliable measure of this behavioral pattern by introducing a bilingual switching questionnaire. As a working hypothesis based on the previous literature about code switching, we decomposed language switching into four constructs: (i) L1 switching tendencies (the tendency to switch to L1; L1-switch); (ii) L2 switching tendencies (L2-switch); (iii) contextual switch, which indexes the frequency of switches usually triggered by a particular situation, topic, or environment; and (iv) unintended switch, which measures the lack of intention and awareness of the language switches. A total of 582 Spanish–Catalan bilingual university students were studied. Twelve items were selected (three for each construct). The correlation matrix was factor-analyzed using minimum rank factor analysis followed by oblique direct oblimin rotation. The overall proportion of common variance explained by the four extracted factors was 0.86. Finally, to assess the external validity of the individual differences scored with the new questionnaire, we evaluated the correlations between these measures and several psychometric (language proficiency) and behavioral measures related to cognitive and attentional control. The present study highlights the importance of evaluating individual differences in language switching using self-assessment instruments when studying the interface between cognitive control and bilingualism

    Increased cerebrospinal fluid albumin and immunoglobulin a fractions forecast cortical atrophy and longitudinal functional deterioration in relapsing-remitting multiple sclerosis

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    Background Currently, no unequivocal predictors of disease evolution exist in patients with multiple sclerosis (MS). Cortical atrophy measurements are, however, closely associated with cumulative disability. Objective Here, we aim to forecast longitudinal magnetic resonance imaging (MRI)-driven cortical atrophy and clinical disability from cerebrospinal fluid (CSF) markers. Methods We analyzed CSF fractions of albumin and immunoglobulins (Ig) A, G, and M and their CSF to serum quotients. Results Widespread atrophy was highly associated with increased baseline CSF concentrations and quotients of albumin and IgA. Patients with increased CSFIgA and CSFIgM showed higher functional disability at follow-up. Conclusion CSF markers of blood–brain barrier integrity and specific immune response forecast emerging gray matter pathology and disease progression in MS

    Increased cortical curvature reflects white matter atrophy in individual patients with early multiple sclerosis

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    AbstractObjectiveWhite matter atrophy occurs independently of lesions in multiple sclerosis. In contrast to lesion detection, the quantitative assessment of white matter atrophy in individual patients has been regarded as a major challenge. We therefore tested the hypothesis that white matter atrophy (WMA) is present at the very beginning of multiple sclerosis (MS) and in virtually each individual patient. To find a new sensitive and robust marker for WMA we investigated the relationship between cortical surface area, white matter volume (WMV), and whole-brain-surface-averaged rectified cortical extrinsic curvature. Based on geometrical considerations we hypothesized that cortical curvature increases if WMV decreases and the cortical surface area remains constant.MethodsIn total, 95 participants were enrolled: 30 patients with early and advanced relapsing–remitting MS; 30 age-matched control subjects; 30 patients with Alzheimer's disease (AD) and 5 patients with clinically isolated syndrome (CIS).Results29/30 MS and 5/5 CIS patients showed lower WMV than expected from their intracranial volume (average reduction 13.0%, P<10−10), while the cortical surface area showed no significant differences compared with controls. The estimated WMV reductions were correlated with an increase in cortical curvature (R=0.62, P=0.000001). Discriminant analysis revealed that the curvature increase was highly specific for the MS and CIS groups (96.7% correct assignments between MS and control groups) and was significantly correlated with reduction of white matter fractional anisotropy, as determined by diffusion tensor imaging and the Expanded Disability Status Scale. As expected by the predominant gray and WM degeneration in AD, no systematic curvature increase was observed in AD.ConclusionWhole-brain-averaged cortical extrinsic curvature appears to be a specific and quantitative marker for a WMV–cortex disproportionality and allows us to assess “pure” WMA without being confounded by intracranial volume. WMA seems to be a characteristic symptom in early MS and can already occur in patients with CIS and should thus be considered in future MS research and clinical studies

    Gray matter integrity predicts white matter network reorganization in multiple sclerosis

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    Multiple sclerosis (MS) is a chronic inflammatory and neurodegenerative disease leading to gray matter atrophy and brain network reconfiguration as a response to increasing tissue damage. We evaluated whether white matter network reconfiguration appears subsequently to gray matter damage, or whether the gray matter degenerates following alterations in white matter networks. MRI data from 83 patients with clinically isolated syndrome and early relapsing–remitting MS were acquired at two time points with a follow-up after 1 year. White matter network integrity was assessed based on probabilistic tractography performed on diffusion-weighted data using graph theoretical analyses. We evaluated gray matter integrity by computing cortical thickness and deep gray matter volume in 94 regions at both time points. The thickness of middle temporal cortex and the volume of deep gray matter regions including thalamus, caudate, putamen, and brain stem showed significant atrophy between baseline and follow-up. White matter network dynamics, as defined by modularity and distance measure changes over time, were predicted by deep gray matter volume of the atrophying anatomical structures. Initial white matter network properties, on the other hand, did not predict atrophy. Furthermore, gray matter integrity at baseline significantly predicted physical disability at 1-year follow-up. In a sub-analysis, deep gray matter volume was significantly related to cognitive performance at baseline. Hence, we postulate that atrophy of deep gray matter structures drives the adaptation of white matter networks. Moreover, deep gray matter volumes are highly predictive for disability progression and cognitive performance

    Synergistic assembly of hyperbranched polyethylenimine and fatty acids leading to unusual supramolecular nanocapsules

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    Self-assembly of hyperbranched polyethylenimine (PEI) and fatty acids leads to supramolecular inverted micellar structures that are able to irreversibly transfer water-soluble guest molecules into organic solvents.Perez Prieto, Julia, [email protected] ; Stiriba, Salah Eddine, [email protected]
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