1,988 research outputs found

    Preparing for retirement - a comparative view : personal experiences of financial preparations from four nations

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    The myth of Ariadne in Catullus’ carmen 64

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    This paper aims to analyse the ekphrastic narrative about Ariadne found in Catullus’ carmen 64 and to show how the poet interweaves myths about Ariadne and Theseus with the celebration of the marriage of Thetis and Peleus in the composition of the poem.Este artigo se propĂ”e a analisar a narrativa ecfrĂĄstica relativa ao mito de Ariadne encontrada no centro do carmen 64 de Catulo e apresentar como o poeta entrelaça a narrativa acerca de Ariadne e Teseu com a celebração do casamento de TĂ©tis e Peleu ao longo desse poema

    Entlastung des Arbeitsmarktes durch Umweltschutz?

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    "Umweltschutzmaßnahmen fĂŒhren nicht nur dazu, daß der Volkswirtschaft Gesundheits-, Material- und VegetationsschĂ€den in Milliardenhöhe erspart bleiben. Umweltschutzmaßnahmen sorgen auch dafĂŒr, daß der Arbeitsmarkt entlastet wird. In diesem Aufsatz wird gezeigt, daß der "job-killer-Umweltschutz"-These (Arbeitsplatzverluste durch Kostenerhöhung in Grenzbetrieben, Konkurrenznachteile auf den AuslandsmĂ€rkten, Standortverlagerungen in das Ausland und Investitionsstaus) nur eine begrenzte Bedeutung zukommt. Denn den wenigen Tausend umweltschutzbedingten Arbeitsplatzverlusten steht eine wesentlich grĂ¶ĂŸere Zahl an UmweltschutzarbeitsplĂ€tzen im Bereich der Industrie und der öffentlichen Hand gegenĂŒber; vorsichtig gerechnet 440.000. Mit einem BĂŒndel weiterer beschĂ€ftigungswirksamer Maßnahmen, wie der Aktivierung des Eigeninteresses aller fĂŒr den Umweltschutz, gezielter Umweltschutzsubventionen bei Unternehmen, höherer Umweltschutzinvestitionen von Bund und LĂ€ndern sowie verstĂ€rkter Arbeitsbeschaffungsmaßnahmen auf dem Umweltsektor, könnten etwa 250.000 bis 300.000 zusĂ€tzliche UmweltschutzarbeitsplĂ€tze geschaffen werden. Insgesamt wĂŒrden sich die UmweltschutzarbeitsplĂ€tze dann auf rund 700.000 bis 750.000 belaufen." (Autorenreferat)Umweltschutz - Auswirkungen, BeschĂ€ftigungseffekte, Arbeitsmarkt

    Micromechanical properties and structural characterization of modern inarticulated brachiopod shells

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    [1] We investigated micromechanical properties and ultrastructure ofthe shells of the modern brachiopod species Lingula anatina, Disciniscalaevis, and Discradisca stella with scanning electron microscopy (SEM,EDX), transmission electron microscopy (TEM) and Vickers microhardnessindentation analyses. The shells are composed of two distinct layers, anouter primary layer and an inner secondary layer. Except for the primarylayer in Lingula anatina, which is composed entirely of organic matter,all other shell layers are laminated organic/inorganic composites. Theorganic matter is built of chitin fibers, which provide the matrix forthe incorporation of calcium phosphate. Amorphous calcium phosphate inthe outer, primary layer and crystalline apatite is deposited into theinner, secondary layer of the shell. Apatite crystallite sizes in theumbonal region of the shell are about 50 x 50 nm, while within thevalves crystallite sizes are significantly smaller, averanging 10 x 25nm. There is great variation in hardness values between shell layers andbetween the investigated brachiopod species. The microhardness of theinvestigated shells is significantly lower than that of inorganichydroxyapatite. This is caused by the predominantly organic materialcomponent that in these shells is either developed as purely organiclayers or as an organic fibrous matrix reinforced by crystallites. Ourresults show that this particular fiber composite material is veryefficient for the protection and the support of the soft animal tissue.It lowers the probability of crack formation and effectively impedescrack propagation perpendicular to the shell by crack-deviationmechanisms. The high degree of mechanical stability and toughness isachieved by two design features. First, there is the fiber compositematerial which overcomes some detrimental and enhances some advantageousproperties of the single constituents, that is the softness andflexibility of chitin and the hardness and brittleness of apatite.Second, there is a hierarchical structuring from the nanometer to amicrometer level. We could identify at least seven levels of hierarchywithin the shells

    Inadequate Clearance of Translocated Bacterial Products in HIV-Infected Humanized Mice

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    Bacterial translocation from the gut and subsequent immune activation are hallmarks of HIV infection and are thought to determine disease progression. Intestinal barrier integrity is impaired early in acute retroviral infection, but levels of plasma lipopolysaccharide (LPS), a marker of bacterial translocation, increase only later. We examined humanized mice infected with HIV to determine if disruption of the intestinal barrier alone is responsible for elevated levels of LPS and if bacterial translocation increases immune activation. Treating uninfected mice with dextran sodium sulfate (DSS) induced bacterial translocation, but did not result in elevated plasma LPS levels. DSS-induced translocation provoked LPS elevation only when phagocytic cells were depleted with clodronate liposomes (clodrolip). Macrophages of DSS-treated, HIV-negative mice phagocytosed more LPS ex vivo than those of control mice. In HIV-infected mice, however, LPS phagocytosis was insufficient to clear the translocated LPS. These conditions allowed higher levels of plasma LPS and CD8+ cell activation, which were associated with lower CD4+/CD8+ cell ratios and higher viral loads. LPS levels reflect both intestinal barrier and LPS clearance. Macrophages are essential in controlling systemic bacterial translocation, and this function might be hindered in chronic HIV infection

    Spt4/5 stimulates transcription elongation through the RNA polymerase clamp coiled-coil motif

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    Spt5 is the only known RNA polymerase-associated factor that is conserved in all three domains of life. We have solved the structure of the Methanococcus jannaschii Spt4/5 complex by X-ray crystallography, and characterized its function and interaction with the archaeal RNAP in a wholly recombinant in vitro transcription system. Archaeal Spt4 and Spt5 form a stable complex that associates with RNAP independently of the DNA–RNA scaffold of the elongation complex. The association of Spt4/5 with RNAP results in a stimulation of transcription processivity, both in the absence and the presence of the non-template strand. A domain deletion analysis reveals the molecular anatomy of Spt4/5—the Spt5 Nus-G N-terminal (NGN) domain is the effector domain of the complex that both mediates the interaction with RNAP and is essential for its elongation activity. Using a mutagenesis approach, we have identified a hydrophobic pocket on the Spt5 NGN domain as binding site for RNAP, and reciprocally the RNAP clamp coiled-coil motif as binding site for Spt4/5
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