6,224 research outputs found

    A description of vascular plant species from an area in the central Sierra Nevada foothills of California

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    Much work has been done on the remarkably diverse flora of California but few specific studies of the foothills of the Central Sierra Nevada Range have been undertaken. One such area is Calaveras County, a region rich in the early history of California. The site chosen for this study ranges from approximately 2350 to 2700 feet in elevation. It is well defined by survey and accessible at all times of the year. The primary objective of the study was to determine what vascular plant species occur naturally in the area. This was accomplished by extensive collections made from April 1970 to July 1971. In addition, recommendations are made to introduce various species that are normally native to the area and to eradicate the noxious species, This will enhance the area for future use as a University of the Pacific field site

    Assaying activity and assessing thermostability of hyperthermophilic enzymes

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    There is now a wide variety of intra- and extra-cellular enzymes available from organisms growing above 75°C, and having sufficient stability to allow assay well above this temperature. For some of these enzymes, to assay below even 95°C will involve measurement below the optimal growth temperature for the organism. The purpose of this chapter is to cover practical aspects of enzyme assay procedures that are specific to high temperatures. Since by far the commonest routine assessment of enzyme stability is activity loss, and because it is always unwise to measure enzyme activity without being confident of its stability during the assay, we include an outline of procedures for measuring enzyme activity loss/stability at high temperatures

    „Allein machen sie dich ein“ – Soziale Arbeit und Gewerkschaften: BegrĂŒndungen, Formen und Perspektiven gewerkschaftlichorganisierter Sozialer Arbeit

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    Soziale Arbeit als ErwerbstĂ€tigkeit und Sozialarbeiter_innen als lohnabhĂ€ngige BeschĂ€ftigte zu betrachten, wird in Zeiten schwindender Tarifbindung sozialer TrĂ€ger und der damit einhergehenden Prekarisierung und Deprofessionalisierung Sozialer Arbeit immer notwendiger. Gesellschaftliche, politische und wirtschaftliche Entwicklungen fĂŒhren in das Thema ein und leiten zur Darstellung der Prekarisierungstendenzen Sozialer Arbeit als ErwerbstĂ€tigkeit und als Profession ĂŒber. Daran anschließend wird der aktuelle Zustand gewerkschaftlicher Organisiertheit der Sozialen Arbeit und ihrer FachkrĂ€fte dargestellt. Hauptschwerpunkt der Arbeit ist es, zu analysieren, warum Soziale Arbeit und Gewerkschaften in nur geringem Bezug zueinander stehen und warum Soziale Arbeit gewerkschaftlich nur marginal organisiert und reprĂ€sentiert ist. Fach- und tarifpolitische Interessen Sozialer Arbeit als Profession und als ErwerbstĂ€tigkeit gilt es in ihren Interdependenzen zu verstehen, nicht zuletzt, um die gewerkschaftliche ReprĂ€sentation Sozialer Arbeit und ihrer FachkrĂ€fte zu erhöhen – im Sinne einer fachlich hochwertigen und professionellen Sozialen Arbeit

    Die ostdeutsche ElektrizitÀtswirtschaft zwischen Volkseigentum und Wettbewerb

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    Betrachtet man die VerĂ€nderungen im letzten Jahrzehnt, so gibt die Entwicklung der ElektrizitĂ€tswirtschaft in der heutigen Bundesrepublik Deutschland ein nahezu allumfassendes Bild von der Transformation einer rein öffentlichen Aufgabe bis hin zu einem rein privatem Gut. Dabei spielten anfangs im Osten Deutschlands planwirtschaftliche EigentumsverhĂ€ltnisse die dominierende Rolle, wĂ€hrend im Westen Deutschland natĂŒrliche Monopole und oligopolistische MĂ€rkte einer starken Regulierung seitens des Staates bedĂŒrfen. Der politische Wandel in der ehemaligen DDR sowie die zunehmenden Schwierigkeiten im regulierten westdeutschen ElektrizitĂ€tsmarkt - im Umfeld einer gemeinsamen Wettbewerbspolitik in der EuropĂ€ischen Union - fĂŒhren schließlich von der Privatisierung hin zu einer Liberalisierung der deutschen Stromwirtschaft. Welche Maßnahmen hierzu im einzelnen ergriffen wurden, unter welchen PrĂ€missen dies geschah und welche Institutionen an den erzielten Ergebnissen einen Anteil haben, dies ist Gegenstand der nachfolgenden AusfĂŒhrungen. Der Aufsatz gliedert sich in zwei Teile, von denen der erste sich mit der Privatisierung und Regulierung der ostdeutschen ElektrizitĂ€tswirtschaft beschĂ€ftigt, und der zweite Teil auf die hoch aktuellen Fragen der Deregulierung der MĂ€rkte eingeht

    Salmonella enterica: a surprisingly well-adapted intracellular lifestyle

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    The infectious intracellular lifestyle of Salmonella enterica relies on the adaptation to nutritional conditions within the Salmonella-containing vacuole (SCV) in host cells. We summarize latest results on metabolic requirements for Salmonella during infection. This includes intracellular phenotypes of mutant strains based on metabolic modeling and experimental tests, isotopolog profiling using (13)C-compounds in intracellular Salmonella, and complementation of metabolic defects for attenuated mutant strains towards a comprehensive understanding of the metabolic requirements of the intracellular lifestyle of Salmonella. Helpful for this are also genomic comparisons. We outline further recent studies and which analyses of intracellular phenotypes and improved metabolic simulations were done and comment on technical required steps as well as progress involved in the iterative refinement of metabolic flux models, analyses of mutant phenotypes, and isotopolog analyses. Salmonella lifestyle is well-adapted to the SCV and its specific metabolic requirements. Salmonella metabolism adapts rapidly to SCV conditions, the metabolic generalist Salmonella is quite successful in host infection

    Investigation on fatigue strength of cut edges produced by various cutting methods for high-strength steels

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    Due to the interest in effective light steel constructions, high-strength steels have gained importance. Different thermal cutting processes are frequently used in the metal processing industry. Besides the weld seams, free cutting edges gain technical and economic relevance as locations for potential fatigue cracks. In this investigation, fatigue tests were carried out on 8-mm-thick samples of S355M and S690Q steels at a stress ratio of R = 0.1. The cutting methods used were oxygen, plasma, laser, and waterjet cutting. Quality improvement methods, like shot peening, grinding, and cutting speed reduction, were applied for some series. The surface roughness was measured to classify the specimens into quality groups according to ISO 9013. The cut edge condition was also characterized by hardness and residual stress measurements. The investigation shows that all tested series exceed the FAT100 class and can be classified in FAT125. Specimens ranged in quality group 2 of ISO 9013 according to the roughness achieve FAT140 regardless of cutting technology or material. According to the ISO 9013, most of the specimens are classified in the quality group 2 and group 3. Fatigue strength results are significantly different in one quality group. No prediction can be made. ISO 9013 has a weak connection to fatigue strength. Quality improvement methods have a significant influence on the fatigue strength and can increase it. Due to reduced cutting speeds, the roughness decreases also. It results in an increase of the fatigue strength in all tested series in this study. In order to make a prediction of the fatigue performance, the standard has to be specified and the cutting process as well as the steel strength should be considered
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