4,009 research outputs found

    Encountering and Countering Tribal Conflict With Film and Dialogue

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    Martin explores the ability of group leaders to overcome resistance to reconciliation in group conflicts, whether innate or otherwise. He uses an example of a group conflict that occurred across religious lines with the pending release of a movie titled Theologians Under Hitler. Even if out-group biases make group conflicts harder to resolve, offsetting that complication might be a predisposition to attend to the views of a respected leader of the in-group

    Correlation functions for ionic motion from NMR relaxation and electrical conductivity in the glassy fast-ion conductor (Li2S)0.56(SiS2)0.44

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    The Li7 NMR spin-lattice relaxation and the electrical conductivity in the typical glassy fast-ion conductor (Li2S)0.56(SiS2)0.44 are discussed from models of Li+ionic motion with distributions of activation energies, as well as from stretched-exponential time-correlation functions. The measured correlation times from the two effects differ by two orders of magnitude, and the derived distributions are shifted greatly relative to each other. We relate the great differences to percolation around the high barriers in the distribution. We present a phenomenological theory that yields good quantitative fits to the observed NMR relaxation with a Gaussian distribution, and to the conductivity and related dielectric properties with the continuous-time random-walk model and the same Gaussian truncated at the percolation limit. This correlates the two effects in a simple and effective way; both time-correlation functions can be calculated approximately from the distributions, and even the dc conductivity can be calculated from the NMR results. The present approach is discussed and compared with previously proposed models to explain the anomalies in ac electrical-conductivity and NMR relaxation rates in glassy fast-ion conductors

    Relaxation and fluctuations in glassy fast-ion conductors: Wide-frequency-range NMR and conductivity measurements

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    Li7 nuclear spin-lattice relaxation rates (R1) versus the temperature at several resonance frequencies (4 to 40 MHz) are reported together with the conductivity measurements, σ(ω), in the range 1 Hz to 3.76 MHz on 0.56Li2S+0.44Si2S, a glassy fast-ionic conductor. Both R1 and σ(ω) are fitted consistently over the whole temperature and frequency range by using a stretched-exponential, i.e., exp(-t/τ*c)β for the corresponding correlation functions (CF). Formulas that relate R1(ω) and σ(ω) and that give the asymptotic behavior as functions of T and ω of both quantities are tested experimentally. We find significant differences between βσrelated to σ(ω) and βR related to R1, which implies a difference in the corresponding correlation functions of the ionic diffusional motion. An apparent order-of-magnitude difference in τ*0 attempt times was derived from these conductivity and NMR measurements. The implications of these findings are discussed in terms of the microscopic mechanisms which lead to fluctuations and relaxation in fast-ionic conductors

    Reply to ‘‘Comment on ‘Correlation functions for ionic motion from NMR relaxation and electrical conductivity in the glassy fast-ion conductor (Li2S)0.56(SiS2)0.44’ ’’

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    Hunt’s Comment criticizes our recent article for combining concepts from percolation theory and effective-medium theories to calculate the dc and ac conductivities in ionic conducting glasses. Our approach was an attempt to describe the dc and ac conductivity with input information from our NMR measurements. We used the continuous-time random-walk theory and reasonable assumptions for the glasses which yielded good fits of the dc and ac conductivities at many temperatures

    Looming struggles over technology for border control

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    New technologies under development, capable of inflicting pain on masses of people, could be used for border control against asylum seekers. Implementation might be rationalized by the threat of mass migration due to climate change, nuclear disaster or exaggerated fears of refugees created by governments. We focus on taser anti-personnel mines, suggesting both technological countermeasures and ways of making the use of such technology politically counterproductive. We also outline several other types of ‘non-lethal’ technology that could be used for border control and raise human rights concerns: high-powered microwaves, armed robots, wireless tasers, acoustic devices/vortex rings, ionizing and pulsed energy lasers, chemical calmatives, convulsants, bioregulators and malodurants. Whether all these possible border technologies will be implemented is a matter for speculation, but their serious human rights implications warrant advance scrutiny

    Age and sex-selective predation moderate the overall impact of predators

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    © 2014 The Authors. Journal of Animal Ecology published by John Wiley & Sons Ltd on behalf of British Ecological Society. Acknowledgements: Thanks to J. Reid, S. Redpath, A. Beckerman and an anonymous reviewer for their helpful comments on a previous version of the manuscript. This work was partly funded by a Natural Environment Research Council studentship NE/J500148/1 to SH and a grant NE/F021402/1 to XL and by Natural Research Limited. Forest Research funded all the fieldwork on goshawks, tawny owls and field voles during 1973–1996. We thank B. Little, P. Hotchin, D. Anderson and all field assistants for their help with data collection and Forest Enterprise, T. Dearnley and N. Geddes for allowing and facilitating work in Kielder Forest. In addition, we are grateful to English Nature and the BTO for kindly issuing licences annually visit goshawk nest sites. Data accessibility: All data associated with the study which have not already been given in the text are available from the Dryad Digital Repository: http://doi.org/10.5061/dryad.h1289 (Hoy et al. 2014).Peer reviewedPublisher PD

    cDNA-RNA subtractive hybridization reveals increased expression of mycocerosic acid synthase in intracellular Mycobacterium bovis BCG.

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    Identifying genes that are differentially expressed by Mycobacterium bovis BCG after phagocytosis by macrophages will facilitate the understanding of the molecular mechanisms of host cell-intracellular pathogen interactions. To identify such genes a cDNA-total RNA subtractive hybridization strategy has been used that circumvents the problems both of limited availability of bacterial RNA from models of infection and the high rRNA backgrounds in total bacterial RNA. The subtraction products were used to screen a high-density gridded Mycobacterium tuberculosis genomic library. Sequence data were obtained from 19 differential clones, five of which contained overlapping sequences for the gene encoding mycocerosic acid synthase (mas). Mas is an enzyme involved in the synthesis of multi-methylated long-chain fatty acids that are part of phthiocerol dimycocerosate, a major component of the complex mycobacterial cell wall. Northern blotting and primer extension data confirmed up-regulation of mas in intracellular mycobacteria and also revealed a putative extended -10 promoter structure and a long untranslated upstream region 5' of the mas transcripts, containing predicted double-stranded structures. Furthermore, clones containing overlapping sequences for furB, groEL-2, rplE and fadD28 were identified and the up-regulation of these genes was confirmed by Northern blot analysis. The cDNA-RNA subtractive hybridization enrichment and high density gridded library screening, combined with selective extraction of bacterial mRNA represents a valuable approach to the identification of genes expressed during intra-macrophage residence for bacteria such as M. bovis BCG and the pathogenic mycobacterium, M. tuberculosis

    A revision of the ‘coelophysoid-grade’ theropod specimen from the Lower Jurassic of the Isle of Skye (Scotland)

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    The broadest diversification of early predatory dinosaurs is represented by the ‘coelophysoid-grade’ neotheropods, but their Hettangian–Sinemurian (c. 191–201 Ma) record is scarce worldwide. More information is needed to shed light on the evolution of this dinosaur group after the end-Triassic mass extinction (c. 201 Ma). Here we revisit the anatomy and phylogeny of one of these earliest Jurassic neotheropod specimens, an isolated partial tibia from the lower Sinemurian of the Isle of Skye (Scotland) that was previously identified as probably closely related to Liliensternus liliensterni and coelophysids. However, we found that the Skye specimen is positioned in the branch leading to Averostra (Ceratosauria + Tetanurae), in a polytomy with Sarcosaurus woodi from the late Hettangian–lower Sinemurian of central England and a clade composed of Tachiraptor admirabilis and Averostra. The morphology of the Skye specimen is congruent with that of referred specimens of Sarcosaurus woodi, but because it probably represents a skeletally immature specimen, we assign it to cf. Sarcosaurus woodi. The Skye specimen increases the number of averostran-line neotheropod specimens recorded in the Lower Jurassic of Europe and current evidence indicates that these forms, and not coelophysoids, were relatively common in this part of the world at that time
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