610 research outputs found

    UV resistance of nucleosides -- an experimental approach

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    The emergence of life on Earth is a highly discussed but still unsolved question. Current research underlines the importance of environments within close proximity to the Earth's surface as they can solve long-standing problems such as polymerization of nucleotides and phosphorylation of nucleosides. However, near-surface settings, for example, ponds or ice shields, are prone to UV irradiation. We investigated the photosensitivity of uracil, uridine, adenosine, cytidine, and guanosine by using Raman microscopy. The samples were irradiated by a UV source with 150~mW/cm\textsuperscript{2} for 10 min. Uracil and uridine showed the highest photosensitivity, while adenosine, cytidine, and guanosine remained stable. The change of spectral features and ab initio quantum calculations indicate the formation of uracil's trans-syn cyclobutane dimer during UV irradiation.Comment: 10 pages, 5 figures, to be published in ACS Earth and Space Chemistr

    Связь параметров электрического отклика на ударное воздействие с качеством контакта цементной матрицы и крупного заполнителя в бетоне

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    The work presents the research results of the parameters of the electric response to impact excitation of the heavy concrete samples with different quality of contact of the cement matrix and coarse aggregate. It is established that a change of the contact zone characteristics lead to the transformation of the spectra of the electric responses, shift of the spectrum towards lower frequencies and decrease in the attenuation coefficient of the energy of the electric responses

    Deinstitutionalized patients, homelessness and imprisonment: A systematic review

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    BackgroundReports linking the deinstitutionalisation of psychiatric care with homelessness and imprisonment have been published widely.AimsTo identify cohort studies that followed up or traced back long-term psychiatric hospital residents who had been discharged as a consequence of deinstitutionalisation.MethodA broad search strategy was used and 9435 titles and abstracts were screened, 416 full articles reviewed and 171 articles from cohort studies of deinstitutionalised patients were examined in detail.ResultsTwenty-three studies of unique populations assessed homelessness and imprisonment among patients discharged from long-term care. Homelessness and imprisonment occurred sporadically; in the majority of studies no single case of homelessness or imprisonment was reported.ConclusionsOur results contradict the findings of ecological studies which indicated a strong correlation between the decreasing number of psychiatric beds and an increasing number of people with mental health problems who were homeless or in prison.</jats:sec

    Qualitätssicherung und Qualitätsentwicklung in der Pandemie. Lessons Learned. Bericht gemäß §28 HS-QSG zum Stand 2021

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    Im dritten Bericht zur Entwicklung der Qualitätssicherung an hochschulischen Bildungseinrichtungen führt die AQ Austria ihre Analysen zur Studierbarkeit fort. Der Bericht fokussiert auf die Maßnahmen, die Hochschulen während der COVID-19-Pandemie zum Erhalt der Studierbarkeit gesetzt haben und die langfristig in den Studienbetrieb integriert werden. Dies erfordert zugleich, den Blick für Prozesse des Krisen- und Qualitätsmanagements sowie Maßnahmen in den Bereichen Forschung und Dritte Mission zu weiten. Auch die AQ Austria war in der Pandemie gezwungen, Veränderungen in der Durchführung von Qualitätssicherungsverfahren umzusetzen. Die dabei gemachten Erfahrungen dienen im Bericht als eine Reflexionsfolie für die Einschätzung künftiger Entwicklungen. (DIPF/Orig.

    Activation of Virus-specific Memory B Cells in the Absence of T Cell Help

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    Humoral immunity is maintained by long-lived plasma cells, constitutively secreting antibodies, and nonsecreting resting memory B cells that are rapidly reactivated upon antigen encounter. The activation requirements for resting memory B cells, particularly the role of T helper cells, are unclear. To analyze the activation of memory B cells, mice were immunized with human cytomegalovirus, a complex human herpesvirus, and tick-born encephalitis virus, and a simple flavivirus. B cell populations devoid of Ig-secreting plasma cells were adoptively transferred into T and B cell–deficient RAG-1−/− mice. Antigenic stimulation 4–6 d after transfer of B cells resulted in rapid IgG production. The response was long lasting and strictly antigen specific, excluding polyclonal B cell activation. CD4+ T cells were not involved since (a) further depletion of CD4+ T cells in the recipient mice did not alter the antibody response and (b) recipient mice contained no detectable CD4+ T cells 90 d posttransfer. Memory B cells could not be activated by a soluble viral protein without T cell help. Transfer of memory B cells into immunocompetent animals indicated that presence of helper T cells did not enhance the memory B cell response. Therefore, our results indicate that activation of virus-specific memory B cells to secrete IgG is independent of cognate or bystander T cell help

    EEG signatures accompanying auditory figure-ground segregation

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    In everyday acoustic scenes, figure-ground segregation typically requires one to group together sound elements over both time and frequency. Electroencephalogram was recorded while listeners detected repeating tonal complexes composed of a random set of pure tones within stimuli consisting of randomly varying tonal elements. The repeating pattern was perceived as a figure over the randomly changing background. It was found that detection performance improved both as the number of pure tones making up each repeated complex (figure coherence) increased, and as the number of repeated complexes (duration) increased – i.e., detection was easier when either the spectral or temporal structure of the figure was enhanced. Figure detection was accompanied by the elicitation of the object related negativity (ORN) and the P400 event-related potentials (ERPs), which have been previously shown to be evoked by the presence of two concurrent sounds. Both ERP components had generators within and outside of auditory cortex. The amplitudes of the ORN and the P400 increased with both figure coherence and figure duration. However, only the P400 amplitude correlated with detection performance. These results suggest that 1) the ORN and P400 reflect processes involved in detecting the emergence of a new auditory object in the presence of other concurrent auditory objects; 2) the ORN corresponds to the likelihood of the presence of two or more concurrent sound objects, whereas the P400 reflects the perceptual recognition of the presence of multiple auditory objects and/or preparation for reporting the detection of a target object

    Anxiety modulates the relation between attention-deficit/hyperactivity disorder severity and working memory-related brain activity

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    Objectives: Individuals with attention-deficit/hyperactivity disorder (ADHD) often have heightened levels of anxiety, which has been associated with worse performance on working memory tasks. Knowledge of the neural pathways underlying the combined presence of ADHD and anxiety may aid in a better understanding of their co-occurrence. Therefore, we investigated how anxiety modulates the effect of ADHD severity on neural activity during a visuospatial working memory (VSWM) task.Methods: Neuroimaging data were available for 371 adolescents and young adults participating in the multicentre cohort study NeuroIMAGE (average age 17.1 years). We analysed the effects of ADHD severity, anxiety severity and their interaction on-task accuracy, and on neural activity associated with working memory (VSWM trials minus baseline), and memory load (high memory load trials minus low load trials).Results: Anxiety significantly modulated the relation between ADHD severity and neural activity in the cerebellum for the working memory contrast, and bilaterally in the striatum and thalamus for the memory load contrast.Conclusions: We found that ADHD with co-occurring anxiety is associated with lowered neural activity during a VSWM task in regions important for information gating. This fits well with previous theorising on ADHD with co-occurring anxiety, and illustrates the neurobiological heterogeneity of ADHD

    An environmental justice perspective on ecosystem services

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    Mainstreaming of ecosystem service approaches has been proposed as one path toward sustainable development. Meanwhile, critics of ecosystem services question if the approach can account for the multiple values of ecosystems to diverse groups of people, or for aspects of inter- and intra-generational justice. In particular, an ecosystem service approach often overlooks power dimensions and capabilities that are core to environmental justice. This article addresses the need for greater guidance on incorporating justice into ecosystem services research and practice. We point to the importance of deep engagement with stakeholders and rights holders to disentangle contextual factors that moderate justice outcomes on ecosystem service attribution and appropriation in socio-political interventions. Such a holistic perspective enables the integration of values and knowledge plurality for enhancing justice in ecosystem services research. This broadened perspective paves a way for transformative ecosystem service assessments, management, and research, which can help inform and design governance structures that nourish human agency to sustainably identify, manage, and enjoy ecosystem services for human wellbeing
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