2,229 research outputs found

    Civil society and democracy in nineteenth century Europe: entanglements, variations, conflicts

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    "It is ironic that the travelogue of a French aristocrat became one of the canonical texts of American democracy. Even today, American liberals and conservatives rely on De la Démocratie en Amérique to support their arguments and assume that Tocqueville's insights, including his conviction that voluntary associations are the bedrock of American democracy, are still relevant today. However, in a historical and transnational perspective, Tocqueville's famous passages in Democracy in America are as unexceptional as the American society of his time, given the enthusiasm for associative sociability by eighteenth and nineteenth-century practitioners of civil society in France, Germany, the Habsburg Empire and Russia. Revisiting the history of these 'sociable societies' provides an answer to the question whether voluntary associations can be considered schools for democracy or not." (author's abstract)"Es entbehrt nicht der Ironie, dass der Reisebericht eines französischen Aristokraten zu einem kanonischen Text der amerikanischen Demokratie aufstieg. Noch heute berufen sich Liberale wie Konservative in den Vereinigten Staaten auf De la Démocratie en Amérique, um ihren politischen Argumenten Gewicht zu geben. Dabei gehen sie davon aus, dass Tocquevilles Analysen, insbesondere seine Überzeugung, die Grundlage der amerikanischen Demokratie beruhe auf ihren freien Vereinigungen, noch heute von Bedeutung sind. Aus historischer und transnational vergleichender Perspektive lässt sich aber feststellen, dass Tocquevilles Einsichten in Die Demokratie in Amerika ebenso wenig einen Sonderstatus einnehmen wie die amerikanische Gesellschaft seiner Zeit. Das zeigt die Leidenschaft der Praktiker der Bürgergesellschaft für gesellige Vereine in Frankreich, den deutschen Staaten, dem Habsburgerreich und Russland im 18. und 19. Jahrhundert. Ein neuer Blick auf die Geschichte dieser 'geselligen Gesellschaften' gibt Antwort auf die Frage, ob freie Vereinigungen Schulen der Demokratie sind oder nicht." (Autorenreferat

    Large nuclear spin polarization in gate-defined quantum dots using a single-domain nanomagnet

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    The electron-nuclei (hyperfine) interaction is central to spin qubits in solid state systems. It can be a severe decoherence source but also allows dynamic access to the nuclear spin states. We study a double quantum dot exposed to an on-chip single-domain nanomagnet and show that its inhomogeneous magnetic field crucially modifies the complex nuclear spin dynamics such that the Overhauser field tends to compensate external magnetic fields. This turns out to be beneficial for polarizing the nuclear spin ensemble. We reach a nuclear spin polarization of ~50%, unrivaled in lateral dots, and explain our manipulation technique using a comprehensive rate equation model

    Construction and Characterization of T7 Bacteriophages Harboring Apidaecin-Derived Sequences

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    The global spread of multi- and pan-resistant bacteria has triggered research to identify novel strategies to fight these pathogens, such as antimicrobial peptides and, more recently, bacteriophages. In a proof-of-concept study, we have genetically modified lytic T7Select phages targeting Escherichia coli Rosetta by integrating DNA sequences derived from the proline-rich antimicrobial peptide, apidaecin. This allowed testing of our hypothesis that apidaecins and bacteriophages can synergistically act on phage-sensitive and phage-resistant E. coli cells and overcome the excessive cost of peptide drugs by using infected cells to express apidaecins before cell lysis. Indeed, the addition of the highly active synthetic apidaecin analogs, Api802 and Api806, to T7Select phage-infected E. coli Rosetta cultures prevented or delayed the growth of potentially phage-resistant E. coli Rosetta strains. However, high concentrations of Api802 also reduced the T7Select phage fitness. Additionally, plasmids encoding Api802, Api806, and Api810 sequences transformed into E. coli Rosetta allowed the production of satisfactory peptide quantities. When these sequences were integrated into the T7Select phage genome carrying an N-terminal green fluorescent protein (GFP-) tag to monitor the expression in infected E. coli Rosetta cells, the GFP–apidaecin analogs were produced in reasonable quantities. However, when Api802, Api806 and Api810 sequences were integrated into the T7Select phage genome, expression was below detection limits and an effect on the growth of potentially phage-resistant E. coli Rosetta strains was not observed for Api802 and Api806. In conclusion, we were able to show that apidaecins can be integrated into the T7Select phage genome to induce their expression in host cells, but further research is required to optimize the engineered T7Select phages for higher expression levels of apidaecins to achieve the expected synergistic effects that were visible when the T7Select phages and synthetic Api802 and Api806 were added to E. coli Rosetta cultures

    Climate change and allergies

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    The climate crisis poses a major challenge to human health as well as the healthcare system and threatens to jeopardize the medical progress made in recent decades. However, addressing climate change may also be the greatest opportunity for global health in the 21st century. The climate crisis and its consequences, such as rising temperatures, forest fires, floods, droughts, and changes in the quality and quantity of food and water, directly and indirectly affect human physical and mental health. More intense and frequent heat waves and declining air quality have been shown to increase all-cause mortality, especially among the most vulnerable. Climate warming alters existing ecosystems and favors biological invasions by species that better tolerate heat and drought. Pathogen profiles are changing, and the transmission and spread of vector-borne diseases are increasing. The spread of neophytes in Europe, such as ragweed, is creating new pollen sources that increase allergen exposure for allergy sufferers. In addition, the overall milder weather, especially in combination with air pollution and increased CO(2) levels, is changing the production and allergenicity of pollen. The phenomenon of thunderstorm asthma is also occurring more frequently. In view of the increasing prevalence of allergic diseases due to climate change, early causal immunomodulatory therapy is therefore all the more important. During a climate consultation, patients can receive individual advice on climate adaptation and resilience and the benefits of CO(2) reduction—for their own and the planet’s health. Almost 5% of all greenhouse gas emissions in Europe come from the healthcare sector. It thus has a central responsibility for a climate-neutral and sustainable transformation

    Crystallization in mass-asymmetric electron-hole bilayers

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    We consider a \textit{mass-asymmetric} electron and hole bilayer. Electron and hole Coulomb correlations and electron and hole quantum effects are treated on first princles by path integral Monte Carlo methods. For a fixed layer separation we vary the mass ratio MM of holes and electrons between 1 and 100 and analyze the structural changes in the system. While, for the chosen density, the electrons are in a nearly homogeneous state, the hole arrangement changes from homogeneous to localized, with increasing MM which is verified for both, mesoscopic bilayers in a parabolic trap and for a macroscopic system.Comment: 10 pages, latex (styles files included

    Os Direitos Humanos e a HistĂłria

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    Tradução do texto “Human Rights and History”, de Stefan-Ludwig Hoffmann, publicado na revista Past & Present, Volume 232, Issue 1, August 2016, Pages 237–278, https://doi.org/10.1093/pastj/gtw01

    Antimicrobial Activity and 70S Ribosome Binding of Apidaecin-Derived Api805 with Increased Bacterial Uptake Rate

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    In view of the global spread of multiresistant bacteria and the occurrence of panresistant bacteria, there is an urgent need for antimicrobials with novel modes of action. A promising class is antimicrobial peptides (AMPs), including them proline-rich AMPs (PrAMPs), which target the 70S ribosome to inhibit protein translation. Here, we present a new designer peptide, Api805, combining the N- and C-terminal sequences of PrAMPs Api137 and drosocin, respectively. Api805 was similarly active against two Escherichia coli B strains but was inactive against E. coli K12 strain BW25113. These different activities could not be explained by the dissociation constants measured for 70S ribosome preparations from E. coli K12 and B strains. Mutations in the SbmA transporter that PrAMPs use to pass the inner membrane or proteolytic degradation of Api805 by lysate proteases could not explain this either. Interestingly, Api805 seems not to bind to the known binding sites of PrAMPs at the 70S ribosome and inhibited in vitro protein translation, independent of release factors, most likely using a “multimodal effect”. Interestingly, Api805 entered the E. coli B strain Rosetta faster and at larger quantities than the E. coli K-12 strain BW25113, which may be related to the different LPS core structure. In conclusion, slight structural changes in PrAMPs significantly altered their binding sites and mechanisms of action, allowing for the design of different antibiotic classes

    Multiwinding based Semi-Dual Active Bridge Converter

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    Modular converter structures are state of the art for fast charging, since high power and short charging times are required. Multiwinding converter structures can bring several positive advantages, like cost and space reduction. However, the increased complexity due to the magnetically coupled ports needs to be handled. This paper introduces a multiwinding based Semidual-Active-Bridge converter with separated output voltages. The related design challenges in terms of independent charging voltage regulation are evaluated and design guidelines for the medium frequency transformer are presented. The theoretical analysis is validated experimentally

    Isolated Multiport Converter as Cost Efficient Solution for DC-Fast Charger of Electric Vehicle

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    The ongoing electrification of the transport sector raises demands for new power electronic solutions. As a consequence, modular converter structures are state of the art for fast charging, since high power and short charging times are required. This work presents a modular multiport DC-DC converter which has the capability to decrease the cost and size of the required charging station. Furthermore, design guidelines for the investigated topology are presented. The analysis is validated with a three port isolated DC-DC converter with separated loads
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