19 resultados para Dissimilar welding


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Knowledge taught at schools, everyday skills and practical know-how. The relevancy of formation for local elites and the corporative self-government of Early Modern Switzerland Daniel Schläppi, Bern There were different kinds of rural elites in Early Modern Switzerland. The diverse parts of the country developed in very dissimilar ways politically and economically. Some regions were dominated by traditional types of agriculture. Some territories were ruled by major cities. In some of the rural Cantons like Uri, Schwyz, Unterwalden, Glarus and Zug a political elite took control over generations and practiced a cultural lifestyle comparable to the famous aristocracies in cities like Bern, Basel, Freiburg, Luzern, Solothurn and Zurich. Intense proto-industrialization formed a completely different sort of elite with strong affinities to industry and trade in other regions. Meanwhile the habitants of the valley close-by stayed farmers like their ancestors (like in Appenzell). In the most conservative parts of the country mercenary business played an important role till the very end of the Ancien Regime and even furthermore. In summery the variety of historical circumstances caused heterogeneous elites all over. Such socio-political diversity provoked a variety of educational backgrounds. I an academic understanding of the term we know only little about literacy in local rural elites. But there is strong evidence that a lively culture of reading and story-telling existed. This means that even simple countrymen seem to have been in possession of some books. The organisation and capacity of the school system is subject of controversial discussions among up to date researchers. The state of research makes us suppose that the people designed to political careers learned their essential skills not only in school but also in everyday life or on the job. Based on the fact that every community and countless public corporations managed their affairs by their own it’s evident that the local elite’s key-players had a large repertoire of techniques and skills like writing, calculating, strategic thinking or knowledge of oral tradition, old usage or important rituals. Unfortunately the historical actors left not that many sources that would tell us precisely how knowledge and know-how were transferred in former times. Hardly any private account books or common correspondence have been conserved. But a huge bunch of sources that originate from corporative self-administration shows us that most local elites were well-educated and had the necessary skills anyway. Above all other sources like for instance the «Topographische Beschreibungen» (topographic descriptions) that were initiated by the «Ökonomische Gesellschaft» of Berne since the sixties of the 18th century provide an insight into pre-modern classrooms. More important information on the historical formation-reality can be gained by the autobiography of the famous poor peasant Ulrich Bräker (1735‒1798) or some of the novels by Albert Bitzius (1797‒1854, better known as Jeremias Gotthelf). The pedagogic writings by Johann Heinrich Pestalozzi (1746‒1827) and the influences by his mentors Johann Rudolf Tschiffeli (1716‒1780) or Philipp Emanuel von Fellenberg (1771‒1884) are quite illustrative as well.

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Clostridium perfringens β-toxin (CPB) is a β-barrel pore-forming toxin and an essential virulence factor of C. perfringens type C strains, which cause fatal hemorrhagic enteritis in animals and humans. We have previously shown that CPB is bound to endothelial cells within the intestine of affected pigs and humans, and that CPB is highly toxic to primary porcine endothelial cells (pEC) in vitro. The objective of the present study was to investigate the type of cell death induced by CPB in these cells, and to study potential host cell mechanisms involved in this process. CPB rapidly induced lactate dehydrogenase (LDH) release, propidium iodide uptake, ATP depletion, potassium efflux, a marked rise in intracellular calcium [Ca(2+)]i, release of high-mobility group protein B1 (HMGB1), and caused ultrastructural changes characteristic of necrotic cell death. Despite a certain level of caspase-3 activation, no appreciable DNA fragmentation was detected. CPB-induced LDH release and propidium iodide uptake were inhibited by necrostatin-1 and the two dissimilar calpain inhibitors PD150606 and calpeptin. Likewise, inhibition of potassium efflux, chelation of intracellular calcium and treatment of pEC with cyclosporin A also significantly inhibited CPB-induced LDH release. Our results demonstrate that rCPB primarily induces necrotic cell death in pEC, and that necrotic cell death is not merely a passive event caused by toxin-induced membrane disruption, but is propagated by host cell-dependent biochemical pathways activated by the rise in intracellular calcium and inhibitable by necrostatin-1, consistent with the emerging concept of programmed necrosis ("necroptosis").

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Within the context of exoplanetary atmospheres, we present a comprehensive linear analysis of forced, damped, magnetized shallow water systems, exploring the effects of dimensionality, geometry (Cartesian, pseudo-spherical, and spherical), rotation, magnetic tension, and hydrodynamic and magnetic sources of friction. Across a broad range of conditions, we find that the key governing equation for atmospheres and quantum harmonic oscillators are identical, even when forcing (stellar irradiation), sources of friction (molecular viscosity, Rayleigh drag, and magnetic drag), and magnetic tension are included. The global atmospheric structure is largely controlled by a single key parameter that involves the Rossby and Prandtl numbers. This near-universality breaks down when either molecular viscosity or magnetic drag acts non-uniformly across latitude or a poloidal magnetic field is present, suggesting that these effects will introduce qualitative changes to the familiar chevron-shaped feature witnessed in simulations of atmospheric circulation. We also find that hydrodynamic and magnetic sources of friction have dissimilar phase signatures and affect the flow in fundamentally different ways, implying that using Rayleigh drag to mimic magnetic drag is inaccurate. We exhaustively lay down the theoretical formalism (dispersion relations, governing equations, and time-dependent wave solutions) for a broad suite of models. In all situations, we derive the steady state of an atmosphere, which is relevant to interpreting infrared phase and eclipse maps of exoplanetary atmospheres. We elucidate a pinching effect that confines the atmospheric structure to be near the equator. Our suite of analytical models may be used to develop decisively physical intuition and as a reference point for three-dimensional magnetohydrodynamic simulations of atmospheric circulation.

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Wildfires are very rare in central Europe, which is probably why fire effects on vegetation have been neglected by most central European ecologists and palaeoecologists. Presently, reconstructions of fire history and fire ecology are almost absent. We analysed sediment cores from lakes on the Swiss Plateau (Lobsigensee and Soppensee) for pollen and charcoal to investigate the relationship between vegetation and fire. Microscopic charcoal evidence suggests increasing regional fire frequencies during the Neolithic (7350-4150 cal. BP, 5400-2200 BC) and the subsequent prehistoric epochs at Lobsigensee, whereas at Soppensee burnings remained rather rare until modern times. Neolithic peaks of charcoal at 6200 and 5500 cal. BP (4250 and 3550 BC) coincided with declines of pollen of fire-sensitive taxa at both sites (e.g., Ulmus, Tilia, Hedera, Fagus), suggesting synchronous vegetational responses to fire at regional scales. However, correlation analysis between charcoal and pollen for the period 6600-4400 cal. BP (4650-2650 BC) revealed no significant link between fire and vegetation at Soppensee, whereas at Lobsigensee increases of Corylus and decreases of Fagus were related to fire events. Fire impact on vegetation increased during the subsequent epochs at both sites. Correlation analyses of charcoal and pollen data for the period 4250-1150 cal. BP (2300 BC -AD 800) suggest that fires were intentionally set to disrupt forests and to provide open areas for arable and pastoral farming (e.g., significant positive correlations between charcoal and Cerealia, Plantago lanceolata, Asteroideae). These results are compared with southern European records (Lago di Origlio, Lago di Muzzano), which are situated in particularly fire-prone environments. After the Mesolithic period (I1 200-7350 cal. BP, 9250-5400 BC), charcoal influx was higher by an order of magnitude in the south, suggesting more frequent fires. Neolithic fires caused similar though more pronounced responses of vegetation in the south (e.g., expansions of Corylus). Post-Neolithic land-use practices involving (controlled) burning culminated in both regions at about 2550 cal. BP (c. 600 BC). However, fire-caused disappearances of entire forest communities were confined to the southern sites. Such differences in fire effects among the sites are explained by the dissimilar importance of fire as a result of different climatic conditions and cultural activities. Our results imply that the remaining (fire-sensitive) fragments of central European vegetation north of the Alps are especially endangered by increasing fire frequencies resulting from predicted climatic change.