"Adrastea" - Quellen zur Rezeption einer kulturgeschichtlichen Zeitschrift

In den Jahren 1985-2000 ist im Deutschen Klassiker Verlag eine unfangreiche, extensiv kommentierte Auswahlausgabe von Herders Werken erschienen, die trotz des eingeschränkten Texbestandes in der Benutzung vermutlich an die Stelle der vor hundert Jahren entstandenen Ausgabe der sämtlichen Werke Herders von Bernhard Suphan treten wird. Der letzte Band enthält eine Auswahl der vergessenen "Adrastea" (weggelassen wurden die meisten poetischen Beilagen und verschiedenen Exzerpte fremder Texte), aus deren Kommentar wichtige Materialien zur Entstehungs- und Wirkungsgeschichte wegen Überschreitung des zulässigen Umfangs ausgeschlossen bleiben mussten. Die vorliegende Quellenedition ergänzt diese Ausgabe und verwendet deren Siglen. ... Die nachfolgend veröffentlichten Briefe, Rezensionen und Gedichte dokumentieren die ambivalente Aufnahme von Herders Zeitschrift unmittelbar nach ihrem Erscheinen

PFAS: forever chemicals — persistent, bioaccumulative and mobile: reviewing the status and the need for their phase out and remediation of contaminated sites

Background Per- and polyfluorinated alkyl substances (PFAS) have received increasing scientific and political attention in recent years. Several thousand commercially produced compounds are used in numerous products and technical processes. Due to their extreme persistence in the environment, humans and all other life forms are, therefore, increasingly exposed to these substances. In the following review, PFAS will be examined comprehensively. Results The best studied PFAS are carboxylic and sulfonic acids with chain lengths of C4 to C14, particularly perfluorooctanoic acid (PFOA) and perfluorooctane sulfonic acid (PFOS). These substances are harmful to aquatic fauna, insects, and amphibians at concentrations of a few µg/L or less, accumulate in organisms, and biomagnify in food webs. Humans, as the final link in numerous food chains, are subjected to PFAS uptake primarily through food and drinking water. Several PFAS have multiple toxic effects, particularly affecting liver, kidney, thyroid, and the immune system. The latter effect is the basis for the establishment of a tolerable weekly dose of only 4.4 ng/kg body weight for the sum of the four representatives PFOA, PFOS, perfluorononanoic acid (PFNA) and perfluorohexane sulfonic acid (PFHxS) by the European Food Safety Authority (EFSA) in 2020. Exposure estimates and human biomonitoring show that this value is frequently reached, and in many cases exceeded. PFAS are a major challenge for analysis, especially of products and waste: single-substance analyses capture only a fragment of the large, diverse family of PFAS. As a consequence, sum parameters have gained increasing importance. The high mobility of per and polyfluorinated carboxylic and sulfonic acids makes soil and groundwater pollution at contaminated sites a problem. In general, short-chain PFAS are more mobile than long-chain ones. Processes for soil and groundwater purification and drinking water treatment are often ineffective and expensive. Recycling of PFAS-containing products such as paper and food packaging leads to carryover of the contaminants. Incineration requires high temperatures to completely destroy PFAS. After PFOA, PFOS and a few other perfluorinated carboxylic and sulfonic acids were regulated internationally, many manufacturers and users switched to other PFAS: short-chain representatives, per- and polyfluorinated oxo carboxylic acids, telomeric alcohols and acids. Analytical studies show an increase in environmental concentrations of these chemicals. Ultra-short PFAS (chain length C1–C3) have not been well studied. Among others, trifluoroacetic acid (TFA) is present globally in rapidly increasing concentrations. Conclusions The substitution of individual PFAS recognized as hazardous by other possibly equally hazardous PFAS with virtually unknown chronic toxicity can, therefore, not be a solution. The only answer is a switch to fluorine-free alternatives for all applications in which PFAS are not essential

Subjektivierte Taylorisierung: Organisation und Praxis medienvermittelter Dienstleistungsarbeit

"Das Buch präsentiert vor dem Hintergrund eines empirischen Forschungsprojektes mit der Perspektive der subjektivierten Taylorisierung einen neuen Blick auf medienvermittelte Dienstleistungen. Jenseits euphemistischer Verweise auf ganzheitliche Aspekte berücksichtigende Arbeitsorganisation, wie sie insbesondere den betrieblichen Selbstdarstellungen eigen sind, aber auch in Distanz zu fatalistisch anmutenden Diagnosen rein tayloristischer Arbeitspraxis wird die Organisation medienvermittelter Arbeit in Call Centern als lebendige Auseinandersetzung zwischen betrieblichen Akteuren gefasst, die eine facettenreiche Arbeitswirklichkeit konstruiert. Die im Zuge der Rationalisierung der Kundenbeziehungen ursprünglich nur als notwendige Ergänzung technisierter Kommunikationswege vorgesehene Nutzung personaler Qualitäten der Arbeitenden verselbständigt sich: statt partieller Kompetenzen wird die ganze Person in die Tätigkeit eingebracht. Den Beschäftigten kommt die Rolle eines mehr oder weniger offen agierenden eigensinnigen Akteurs zu, der individuelle Ansprüche an die Arbeit unter Umständen nicht nur (ggf. kollektiv) formuliert, sondern alltäglich praktiziert. Das Management sieht sich vor einen neuen Legitimationsdruck hinsichtlich des eigenen Wirkens gestellt und zieht sich durch das Delegieren praxisnaher Gestaltungsfelder an untere Hierarchieebenen auf Rahmensetzungen und deren Kontrolle zurück. In diesen gegenläufigen Bewegungen des Eindringens und des Rückzugs etabliert sich eine Arbeitswirklichkeit, die gleichermaßen durch kleinteilige Kontrolle wie partiell große Freiräume gekennzeichnet ist. Subjektivierte Taylorisierung stellt damit eine erweiterte Entäußerung personaler Kompetenzen wie den Zwang zur, aber auch die Chance auf ausgeweitete Partizipation dar." (Autorenreferat

Advanced Hyperspectral Analysis of Sediment Core Samples from the Chew Bahir Basin, Ethiopian Rift, in the Spectral Range from 0.25 to 17 µm:Support for Climate Proxy Interpretation

Establishing robust environmental proxies at newly investigated terrestrial sedimentary archives is a challenge, because straightforward climate reconstructions can be hampered by the complex relationship between climate parameters and sediment composition, proxy preservation or (in)sufficient sample material. We present a minimally invasive hyperspectral bidirectional reflectance analysis on discrete samples in the wavelength range from 0.25 to 17 mu m on 35 lacustrine sediment core samples from the Chew Bahir Basin, southern Ethiopia for climate proxy studies. We identified and used absorption bands at 2.2 mu m (Al-OH), at 2.3 mu m (Mg-OH), at 1.16 mu m (analcime), and at 3.98 mu m (calcite) for quantitative spectral analysis. The band depth ratios at 2.3/2.2 mu m in the spectra correlate with variations in the potassium content of the sediment samples, which also reflect periods of increased Al-to-Mg substitution in clay minerals during drier climatic episodes. During these episodes of drier conditions, absorption bands diagnostic of the presence of analcime and calcite support this interpretation, with analcime indicating the driest conditions. These results could be compared to qualitative analysis of other characteristic spectral properties in the spectral range between 0.25 and 17 mu m. The results of the hyperspectral measurements complement previous sedimentological and geochemical analyses, allowing us in particular to resolve more finely the processes of weathering in the catchment and low-temperature authigenic processes in the sediment. This enables us to better understand environmental changes in the habitat of early humans

Generation of proton-motive force by an archaeal terminal quinol oxidase from Sulfolobus acidocaldarius

The terminal quinol oxidase of the cytochrome aa3 type was isolated from the extreme thermo-acidophilic archaeon Sulfolobus acidocaldarius. In micellar solution, the enzyme oxidized various quinols and exerted the highest activity with the physiological substrate caldariella quinol. The enzyme was functionally reconstituted into monolayer liposomes composed of archaeal tetraether lipids also derived from S. acidocaldarius. With the electron donor system ascorbate and N,N,N',N'-tetramethyl-p-phenylenediamine, the reconstituted enzyme was more active in the archaeal lipids as compared to lipids derived from Escherichia coli at temperatures above 50°C. Due to the low proton permeability of the tetraether lipids, it was possible to generate a steady-state transmembrane electrical potential (ΔΨ, interior negative), and transmembrane pH gradient (ΔpH, interior alkaline) at temperatures up to 70°C. The successful functional reconstitution of the cytochrome aa3-type quinol oxidase from Sulfolobus identifies it as the key energy converter in the respiratory system of this hyperthermophilic archaeon

Advanced Hyperspectral Analysis of Sediment Core Samples from the Chew Bahir Basin, Ethiopian Rift, in the Spectral Range from 0.25 to 17 µm: Support for Climate Proxy Interpretation

Establishing robust environmental proxies at newly investigated terrestrial sedimentary archives is a challenge, because straightforward climate reconstructions can be hampered by the complex relationship between climate parameters and sediment composition, proxy preservation or (in)sufficient sample material. We present a minimally invasive hyperspectral bidirectional reflectance analysis on discrete samples in the wavelength range from 0.25 to 17 µm on 35 lacustrine sediment core samples from the Chew Bahir Basin, southern Ethiopia for climate proxy studies. We identified and used absorption bands at 2.2 μm (Al–OH), at 2.3 μm (Mg–OH), at 1.16 μm (analcime), and at 3.98 μm (calcite) for quantitative spectral analysis. The band depth ratios at 2.3/2.2 μm in the spectra correlate with variations in the potassium content of the sediment samples, which also reflect periods of increased Al-to-Mg substitution in clay minerals during drier climatic episodes. During these episodes of drier conditions, absorption bands diagnostic of the presence of analcime and calcite support this interpretation, with analcime indicating the driest conditions. These results could be compared to qualitative analysis of other characteristic spectral properties in the spectral range between 0.25 and 17 µm. The results of the hyperspectral measurements complement previous sedimentological and geochemical analyses, allowing us in particular to resolve more finely the processes of weathering in the catchment and low-temperature authigenic processes in the sediment. This enables us to better understand environmental changes in the habitat of early humans

Interleukin-7 Links T Lymphocyte and Intestinal Epithelial Cell Homeostasis

Interleukin-7 (IL-7) is a major survival factor for mature T cells. Therefore, the degree of IL-7 availability determines the size of the peripheral T cell pool and regulates T cell homeostasis. Here we provide evidence that IL-7 also regulates the homeostasis of intestinal epithelial cells (IEC), colon function and the composition of the commensal microflora. In the colon of T cell-deficient, lymphopenic mice, IL-7-producing IEC accumulate. IEC hyperplasia can be blocked by IL-7-consuming T cells or the inactivation of the IL-7/IL-7R signaling pathway. However, the blockade of the IL-7/IL-7R signaling pathway renders T cell-deficient mice more sensitive to chemically-induced IEC damage and subsequent colitis. In summary, our data demonstrate that IL-7 promotes IEC hyperplasia under lymphopenic conditions. Under non-lymphopenic conditions, however, T cells consume IL-7 thereby limiting IEC expansion and survival. Hence, the degree of IL-7 availability regulates both, T cell and IEC homeostasis

Bound States in the Hot Electroweak Phase

The high temperature phase of the electroweak standard theory is described by a strongly coupled SU(2)-Higgs-model in three dimensions. As in the Abbott-Farhi-model Higgs and W-boson are low lying bound states. Using a method by Simonov based on the Feynman-Schwinger representation of correlators we calculate the masses of these states. Our results are compared with lattice masses.Comment: 8 pages, 2 figures; a compressed postscript including the figures is available at http://www.thphys.uni-heidelberg.de/~laser/hd-thep-95-42.ps.