Mobilization and isotope fractionation of chromium during water-rock interaction in presence of siderophores

Chromium mobilization and isotope fractionation during water-rock interaction in presence of the biogenic siderophore desferrioxamine B (DFOB) was studied with batch leaching experiments on chromitite and other igneous oxide and silicate rocks. Siderophores are a group of organic ligands synthesized and excreted by bacteria, fungi and plants to enhance the bioavailability of key nutrients like Fe. However, the DFOB siderophore also has a strong affinity for complexation with other metals such as Cr, U and rare earth elements. Here we show that leaching of rocks in the presence of the hydroxamate siderophore DFOB significantly increased the mobilization of Cr from all investigated rocks and caused an enrichment of the heavier 53Cr isotope in leachates from chromitite (δ53Crleach = +0.15 ± 0.087‰ to +2.14 ± 0.042‰) and from altered silicate rock (δ53Crleach = +0.48 ± 0.07‰). In contrast, stable isotope fractionation of Cr was not observed in DFOB leachates of pristine silicate and low-Cr oxide rocks. Leaching in the presence of citric acid significantly enhanced Cr mobility, but did not result in fractionation of Cr isotopes. Chromium isotope fractionation is used in geochemistry as a quantitative proxy for oxidative weathering, because Cr(III) is oxidized to Cr(VI) in presence of MnO2 and the associated Cr isotope fractionation is commonly linked to the presence of oxygen in the atmosphere. Our findings indicate that the presence of specific biogenic ligands with a high affinity for Cr may also cause Cr isotope fractionation. The presence of biomolecules like siderophores during weathering, hydrothermal alteration or during mineral precipitation, therefore, may put constraints on the applicability of certain trace metals and their isotopes as redox proxies in modern and past environments. The results of our study also suggest that siderophores may have a high potential for (bio)remediation of Cr-contaminated sites and detoxification of contaminated natural waters

Campaign Comics: The Use of Comic Books for Strategic Political Communication

Political parties have long used comic books in their political campaigns. Whereas both ideological and political messages in comics as well as the social and political commentary in editorial cartoons have received vast scholarly attention, comic books and their use for strategic communication are rarely addressed. Thus, this article discusses the use of comic books in political campaigns and analyzes the mass media discourse on comic books used in the 2010 election campaign in Vienna, Austria. Results show the actors in the coverage put special focus on the violent and xenophobic content of the comics. Although these types of content gained much attention, the media failed to discuss the suitability of comics for political purposes

Struktureller Wandel selbstaendiger Erwerbsarbeit Analysen auf der Grundlage der Scientific Use Files der Mikrozensen

'Grundsaetzlich wird in der Literatur ein Anstieg an selbstaendig Erwerbstaetigen konstatiert. Dabei handelt es sich allerdings um Analysen, die einerseits querschnittsbezogen sind und andererseits wenig ins Detail gehen. Bei einer Analyse ist aber auch die zeitliche Entwicklung zu beachten, da ein struktureller Wandel sich ueber einen laengeren Zeitraum vollzieht. Hier bieten die Scientific Use Files der Mikrozensen einen Ansatzpunkt fuer tiefer gehende Analysen. Um ueber die Entwicklung im Bereich der selbstaendigen Erwerbstaetigkeit weitere Anhaltspunkte zu gewinnen, wurde anhand von Scientific Use Files aus den Jahren 1989, 1991, 1993, 1995 bis 1998 und 2000 eine Zeitverlaufsanalyse durchgefuehrt. Die Fragen, denen in der Analyse nachgegangen wurde, sind: In welchen Berufsgruppen kam es zu signifikanten Veraenderungen bei den selbstaendig Erwerbstaetigen ueber den betrachteten Zeitraum? Hat sich die Entwicklung selbstaendiger Erwerbstaetigkeit in West- und Ostdeutschland anders vollzogen? Gab es eine geschlechtsspezifische Entwicklung? Insgesamt gesehen deutet sich an, dass der Uebergang in eine 'Informations- und Dienstleistungsgesellschaft' weder kontinuierlich noch in allen Dienstleistungsbereichen vergleichbar verlaeuft. Die Entwicklung ist gepraegt von erheblichen Veraenderungen im Zeitablauf. So kam es selbst bei Gruppen, die im Endeffekt ein ueberdurchschnittliches Wachstum hatten, zwischen den Jahren zu niedrigen und teilweise sogar zu negativen Aenderungsraten. Der Uebergang in eine Dienstleistungsgesellschaft vollzieht sich nicht ausschliesslich in 'neuen' Berufsfeldern, sondern geht mit einer teilweise ueberproportionalen Zunahme von Berufstaetigkeiten in klassischen Bereichen, insbesondere der Rechtsberatung und der Aerzte/innen, einher. Weiterhin zeigt die Analyse, dass in Deutschland zwischen 1991 bis 2000 eine bestaendige Zunahme selbstaendig Erwerbstaetiger erfolgte, wobei sich der Anteil von Einpersonenunternehmen um rund fuenf Prozentpunkte auf annaehernd 50 v.H. erhoehte. Dabei war die Entwicklung in West- und Ostdeutschland bis Mitte der 90er Jahre unterschiedlich und fuehrte zu einer Anpassung der ostdeutschen an die westdeutschen Strukturen. Hervorzuheben ist ferner, dass das Verhaeltnis von selbstaendig erwerbstaetigen Frauen zu Maennern (etwa 3 zu 7) ueber die Zeit relativ stabil geblieben ist. Es liegen somit keine Indizien fuer einen strukturellen Wandel vor, der zu einer Angleichung der Anzahl Selbstaendiger zwischen den Geschlechtern gefuehrt haette. Die vorliegende Arbeit ist eher als ein erster Schritt in Richtung einer umfassenden, die zahlreichen Facetten selbstaendiger Erwerbsarbeit beruecksichtigenden Analyse zu sehen, als dass sie eine die Entwicklung in den 90er Jahren abschliessend behandelnde Untersuchung darstellt. So kann sie als Anknuepfungspunkt fuer zahlreiche vertiefende und ergaenzende Arbeiten dienen.' (Autorenreferat)'In literature, a rise in the number of self-employed people is basically stated. The results are based on cross-section data from one year and for the most part the analyses are not very detailed. But in an analysis one also has to pay attention to the development over time, because a structural change will only show itself over a long time. To obtain further indications of the development within the field of self-employment, an analysis on the basis of the scientific use files from the years 1989, 1991, 1993, 1995 to 1998 and 2000 was carried out. The questions, which were especially considered, are: In which professional group the development was significant? Were there differences in the development in West- and East-Germany? Was there a gender specific development? Overall, the analysis indicates, that the transition into an information- and service-oriented society is neither continuously nor the same in all services areas. The development is marked by dramatic changes over time. Even professional groups, which had an above average increase at the end, sometimes show little or partially negative growth rates. The transition into a service-oriented society takes place not solely in 'new' jobs, but on the contrary, it is a concomitant of a disproportionate rise in some classic independent professions, e.g. lawyers and physicians. Furthermore, the analysis shows the steady rise in the numbers of self-employed people in Germany between 1989 and 2000 with an increase of about five percentage point of the solo-self-employed people to roughly 50 percent. The development in West- and East-Germany was different until the mid-90s, which leads to an adjustment of the East-to the West-German structures. It is to emphasise, that the relation of self-employed women to self-employed men (3 to 7) is reasonably stable over the time period. So there are no indications of a structural change, with leads to an adaptation of the numbers of self-employed between the genders. The paper is rather a first step in the direction of a comprehensive study, which takes the numerous facets of self-employment into account, than a definitive analysis of the development of self-employed people in the 90s. It has to be seen as a starting point for more detailed and complementary analyses.' (author's abstract)Available from Universitaet Bremen, Zentrum fuer Sozialpolitik, Bremen (DE) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Globalisation and the welfare state A retrospective

Im Grundsatz gibt es drei Positionen zum Zusammenhang zwischen Globalisierung und Wohlfahrtsstaat. Die erste Position sieht die Globalisierung als Ursache fuer die chronische Krise des Wohlfahrtsstaats. Im Zuge der Oeffnung nationaler Volkswirtschaften fuer den internationalen Markt sind die Staaten gezwungen, den Imperativen des internationalen Wettbewerbs zu gehorchen, was die Beschneidung kostenintensiver sozialpolitischer Programme erfordert (Globalisierungstheorie). Die zweite Position sieht die Globalisierung nicht als Ursache fuer die Krise des Wohlfahrtsstaats. Vertreter dieser Auffassung sehen weder einen theoretischen Grund noch einen empirischen Beleg fuer die Auffassung, dass die politische Autonomie der Nationalstaaten aufgrund der zunehmenden wirtschaftlichen Interdependenzen abgenommen haette (Globalisierungsskeptiker). Die dritte Position sieht die Globalisierung nicht als Ursache, sondern als Folge der Probleme des Wohlfahrtsstaats und als Teil einer Loesung dieser Probleme (Revisionismus). Der Verfasser diskutiert die drei Positionen im Lichte deskriptiver statistischer Daten fuer die OECD-Laender. (ICEUebers)'There are basically three stories about the globalisation-welfare state nexus. The first story argues that globalisation is the cause of the chronic crisis of the welfare state. As national economies open to the international market, governments are forced to adapt to the imperatives of global competition, and this means cutting cost-intensive welfare programs (globalisation theory). The second story argues that whatever the cause of the welfare state crisis, globalisation is not part of it. There is neither theoretical reason nor empirical evidence to believe that national policy autonomy has decreased due to increasing economic interdependencies (globalisation sceptics). The third story holds that globalisation, far from causing the welfare state's troubles, is a consequence of these troubles, and part of their solution (revisionism). The paper reviews each of these stories, and counterposes them to simple descriptive statistics on OECD countries.' (author's abstract)German title: Globalisierung und der Wohlfahrtsstaat: ein Blick zurueckAvailable from Universitaet Bremen, SFB 597 Staatlichkeit im Wandel, Bremen (DE) / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman

Data for spread of bacteria in soil

Dataset related to the paper 'Influence of soil structure on the spread of Pseudomonas fluorescens in soil at microscale' The objective of the study was to determine the influence of soil pore characteristics on the spread of bacteria in soil. Bacteria were introduced and locally and allowed to spread through soil. Soil was resin impregnated and the location of bacteria was observed in thin sections. X-ray CT was used to determine the physical characteristics of the pore space. The data set contains the raw data published in the accompanying paper. Treatment refers to the bulk density of the soil and 2 thin sections were counted for each sample. at each micro-site in soil pore characteristics are given in the table and the number of bacterial cells found in that section through observation and counting under the microscope. Counts are converted to cell densities. The data relate to the spread of bacteria and further analysis of the data is described in the pape