58 research outputs found

    Rotational cooling of heteronuclear molecular ions with ^1-Sigma, ^2-Sigma, ^3-Sigma and ^2-Pi electronic ground states

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    The translational motion of molecular ions can be effectively cooled sympathetically to translational temperatures below 100 mK in ion traps through Coulomb interactions with laser-cooled atomic ions. The ro-vibrational degrees of freedom, however, are expected to be largely unaffected during translational cooling. We have previously proposed schemes for cooling of the internal degrees of freedom of such translationally cold but internally hot heteronuclear diatomic ions in the simplest case of ^1-Sigma electronic ground state molecules. Here we present a significant simplification of these schemes and make a generalization to the most frequently encountered electronic ground states of heteronuclear molecular ions: ^1-Sigma, ^2-Sigma, ^3-Sigma and ^2-Pi. The schemes are relying on one or two laser driven transitions with the possible inclusion of a tailored incoherent far infrared radiation field.Comment: 16 pages, 13 figure

    Characterizing RecA-Independent Induction of Shiga toxin2-Encoding Phages by EDTA Treatment

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    Background: The bacteriophage life cycle has an important role in Shiga toxin (Stx) expression. The induction of Shiga toxin-encoding phages (Stx phages) increases toxin production as a result of replication of the phage genome, and phage lysis of the host cell also provides a means of Stx toxin to exit the cell. Previous studies suggested that prophage induction might also occur in the absence of SOS response, independently of RecA. Methodology/Principal Findings: The influence of EDTA on RecA-independent Stx2 phage induction was assessed, in laboratory lysogens and in EHEC strains carrying Stx2 phages in their genome, by Real-Time PCR. RecA-independent mechanisms described for phage l induction (RcsA and DsrA) were not involved in Stx2 phage induction. In addition, mutations in the pathway for the stress response of the bacterial envelope to EDTA did not contribute to Stx2 phage induction. The effect of EDTA on Stx phage induction is due to its chelating properties, which was also confirmed by the use of citrate, another chelating agent. Our results indicate that EDTA affects Stx2 phage induction by disruption of the bacterial outer membrane due to chelation of Mg 2+. In all the conditions evaluated, the pH value had a decisive role in Stx2 phage induction. Conclusions/Significance: Chelating agents, such as EDTA and citrate, induce Stx phages, which raises concerns due to their frequent use in food and pharmaceutical products. This study contributes to our understanding of the phenomenon o

    Social impact bonds and public service reform: back to the future of New Public Management?

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    This article explores where the increasing adoption of SIBs and outcomes-based contracting may lead public service systems—toward New Public Governance, or ‘back’ to New Public Management. We present analysis from the first significant longitudinal qualitative study of a major UK SIB focused on improving outcomes in the context of social determinants of health to analyze how the two governance logics manifest and interact across the SIB lifecourse. We find that while both governance logics were present at initiation, over time NPM elements strengthened while NPG elements weakened. Two inalienable elements of the SIB model—investor power and data requirements for contract management—appeared to drive this change. Our findings provide evidence that SIBs promote a retrenchment of NPM, rather than a transition to NPG or a hybridization of the two governance logics. Findings also show how NPM, rather than a transitional stage toward NPG, can prove the more resilient and dominant governance logic within institutional forms
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