1,070 research outputs found

    Heinrich Hoffmann und sein Struwwelpeter in der Universitätsbibliothek Johann Christian Senckenberg Frankfurt am Main

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    In der Frankfurter Universitätsbibliothek befindet sich eine Vielzahl an handschriftlichen und gedruckten Materialien von und ßber Heinrich Hoffmann. Hier eine Auswahl (Stand: April 2009)

    Radon-220 calibration of near-surface turbulent gas transport

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    Activity concentration profiles of the short-lived radon isotope 220Rn (half-life 56 seconds) in the lowest 50 cm above the soil are used to study near-surface gas transport processes. The experimental data are compared to profiles calculated by solving the one-dimensional diffusion equation for radioactive atoms with a linear increase of the eddy diffusion coefficient K with altitude according to K(z) = K0 + Kz.Z. The slope KZ in this model and the radon flux from the surface are continuously calculated from the activity measurements in time steps of one hour. Transport times for Rn atoms from an altitude Z1 = 5 cm to an altitude Z2 = 20 cm are typically between one and two minutes in stable meteorological conditions when the friction velocity u* is below 0.1 m/s

    An experimental determination of the scale length of N2O in the soil of a grassland

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    Concentration profiles of N2O in a grassland soil and dynamic response curves to disturbance of the soil concentration (relaxation curves) were measured with a new membrane tube technique. Diffusive properties of the soil were derived from 222Rn measurements. The mathematical analysis of the relaxation curves yielded N2O uptake rates U soil diffusivities Ds, scale lengths z*, and production rates P at different levels under the surface. The following ranges were found during 2 days of measurements: Ds = (0.4–5) × 10−7 m2 s−1, U = (1–20) × 10−4 s−1, z* = 0.7–2.8 cm, and P = 0.02–4.4 ppb s−1. These values were used to reproduce the measured N2O concentration profiles with a one-dimensional diffusive transport model of N2O in the soil air-filled pore space and to deduce flux profiles. Bidirectional fluxes occurred with small deposition fluxes up to a few ppt ms−1 during intensive growing phases of the grass. Uptake rates were high enough that N2O produced at greater depth did not reach the atmosphere

    Increasing Temperature and Microplastic Fibers Jointly Influence Soil Aggregation by Saprobic Fungi

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    Microplastic pollution and increasing temperature have potential to influence soil quality; yet little is known about their effects on soil aggregation, a key determinant of soil quality. Given the importance of fungi for soil aggregation, we investigated the impacts of increasing temperature and microplastic fibers on aggregation by carrying out a soil incubation experiment in which we inoculated soil individually with 5 specific strains of soil saprobic fungi. Our treatments were temperature (ambient temperature of 25°C or temperature increased by 3°C, abruptly versus gradually) and microplastic fibers (control and 0.4% w/w). We evaluated the percentage of water stable aggregates (WSA) and hydrolysis of fluorescein diacetate (FDA) as an indicator of fungal biomass. Microplastic fiber addition was the main factor influencing the WSA, decreasing the percentage of WSA except in soil incubated with strain RLCS 01, and mitigated the effects of temperature or even caused more pronounced decrease in WSA under increasing temperature. We also observed clear differences between temperature change patterns. Our study shows that the interactive effects of warming and microplastic fibers are important to consider when evaluating effects of global change on soil aggregation and potentially other soil processes

    04041 Abstracts Collection -- Component-Based Modeling and Simulation

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    From 18.01.04 to 23.01.04, the Dagstuhl Seminar 04041 ``Component-Based Modeling and Simulation\u27\u27 was held in the International Conference and Research Center (IBFI), Schloss Dagstuhl. During the seminar, several participants presented their current research, and ongoing work and open problems were discussed. Abstracts of the presentations given during the seminar as well as abstracts of seminar results and ideas are put together in this paper. The first section describes the seminar topics and goals in general. Links to extended abstracts or full papers are provided, if available

    Schaltungsdesign mit VHDL

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    Die Ampelkoalition

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    Nach der Bundestagswahl 2021 kam es in Deutschland zum ersten Mal seit den 1950er-Jahren zu einer Drei-Parteien-Koalition. Was bedeutet das für die politische Repräsentation der Wähler*innen? Und wie wurden die Wahlversprechen in das Regierungsprogramm übersetzt? Die Autor*innen gehen diesen Fragen sowohl allgemein als auch für vier zentrale Politikfelder (Verkehrswende, Bildungsgerechtigkeit, Familie und Beruf, Digitalisierung in der Gesundheitspolitik) nach. Sie untersuchen, was vor den Wahlen versprochen wurde, wie dies Eingang in die Sondierungsgespräche fand und unter welchen Reibungsverlusten es schließlich im Koalitionsvertrag steht

    Soil Saprobic Fungi Differ in Their Response to Gradually and Abruptly Delivered Copper

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    The overwhelming majority of studies examining environmental change deliver treatments abruptly, although, in fact, many important changes are gradual. One example of a gradually increasing environmental stressor is heavy metal contamination. Essential heavy metals, such as copper, play an important role within cells of living organisms but are toxic at higher concentrations. In our study, we focus on the effects of copper pollution on filamentous soil fungi, key players in terrestrial ecosystem functioning. We hypothesize that fungi exposed to gradually increasing copper concentrations have higher chances for physiological acclimation and will maintain biomass production and accumulate less copper, compared to fungi abruptly exposed to the highest copper concentration. To test this hypothesis, we conducted an experiment with 17 fungal isolates exposed to gradual and abrupt copper addition. Contrary to our hypothesis, we find diverse idiosyncratic responses, such that for many fungi gradually increasing copper concentrations have more severe effects (stronger growth inhibition and higher copper accumulation) than an abrupt increase. While a number of environmental change studies have accumulated evidence based on the magnitude of changes, the results of our study imply that the rate of change can be an important factor to consider in future studies in ecology, environmental science, and environmental management

    Anti-CD20 Depletes Meningeal B Cells but Does Not Halt the Formation of Meningeal Ectopic Lymphoid Tissue

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    Objective To investigate whether anti-CD20 B-cell-depleting monoclonal antibodies (alphaCD20 mAbs) inhibit the formation or retention of meningeal ectopic lymphoid tissue (mELT) in a murine model of multiple sclerosis (MS). Methods We used a spontaneous chronic experimental autoimmune encephalomyelitis (EAE) model of mice with mutant T-cell and B-cell receptors specific for myelin oligodendrocyte glycoprotein (MOG), which develop meningeal inflammatory infiltrates resembling those described in MS. alphaCD20 mAbs were administered in either a preventive or a treatment regimen. The extent and cellular composition of mELT was assessed by histology and immunohistochemistry. Results alphaCD20 mAb, applied in a paradigm to either prevent or treat EAE, did not alter the disease course in either condition. However, alphaCD20 mAb depleted virtually all B cells from the meningeal compartment but failed to prevent the formation of mELT altogether. Because of the absence of B cells, mELT was less densely populated with immune cells and the cellular composition was changed, with increased neutrophil granulocytes. Conclusions These results demonstrate that, in CNS autoimmune disease, meningeal inflammatory infiltrates may form and persist in the absence of B cells. Together with the finding that alphaCD20 mAb does not ameliorate spontaneous chronic EAE with mELT, our data suggest that mELT may have yet unknown capacities that are independent of B cells and contribute to CNS autoimmunity

    Anti-CD20 B-cell depletion enhances monocyte reactivity in neuroimmunological disorders

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    <p>Abstract</p> <p>Background</p> <p>Clinical trials evaluating anti-CD20-mediated B-cell depletion in multiple sclerosis (MS) and neuromyelitis optica (NMO) generated encouraging results. Our recent studies in the MS model experimental autoimmune encephalomyelitis (EAE) attributed clinical benefit to extinction of activated B-cells, but cautioned that depletion of naĂŻve B-cells may be undesirable. We elucidated the regulatory role of un-activated B-cells in EAE and investigated whether anti-CD20 may collaterally diminish regulatory B-cell properties in treatment of neuroimmunological disorders.</p> <p>Methods</p> <p>Myelin oligodendrocyte glycoprotein (MOG) peptide-immunized C57Bl/6 mice were depleted of B-cells. Functional consequences for regulatory T-cells (Treg) and cytokine production of CD11b<sup>+ </sup>antigen presenting cells (APC) were assessed. Peripheral blood mononuclear cells from 22 patients receiving anti-CD20 and 23 untreated neuroimmunological patients were evaluated for frequencies of B-cells, T-cells and monocytes; monocytic reactivity was determined by TNF-production and expression of <it>signalling lymphocytic activation molecule </it>(SLAM).</p> <p>Results</p> <p>We observed that EAE-exacerbation upon depletion of un-activated B-cells closely correlated with an enhanced production of pro-inflammatory TNF by CD11b<sup>+ </sup>APC. Paralleling this pre-clinical finding, anti-CD20 treatment of human neuroimmunological disorders increased the relative frequency of monocytes and accentuated pro-inflammatory monocyte function; when reactivated ex vivo, a higher frequency of monocytes from B-cell depleted patients produced TNF and expressed the activation marker SLAM.</p> <p>Conclusions</p> <p>These data suggest that in neuroimmunological disorders, pro-inflammatory APC activity is controlled by a subset of B-cells which is eliminated concomitantly upon anti-CD20 treatment. While this observation does not conflict with the general concept of B-cell depletion in human autoimmunity, it implies that its safety and effectiveness may further advance by selectively targeting pathogenic B-cell function.</p
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