25,031 research outputs found

    Representation in Westminster in the 1990s : The ghost of Edmund Burke

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    Why are 'trustee' notions of representation still invoked in the UK House of Commons in the 1990s? In answering this question this article analyses the premises of Burkean theory and the arguments that these premises are of little relevance in the late twentieth century. Despite these dismissals of trusteeship, Burkean ideas are still articulated in the Commons some 200 years after they were first voiced. The idea of trusteeship can prove extremely useful to justify the actions of representatives when those actions conflict with constituency 'opinion', party policy or the wishes of interest groups. Examples of the occasions when Burkean notions have been invoked in the 1990s are provided

    A combined R-matrix eigenstate basis set and finite-differences propagation method for the time-dependent Schr\"{od}dinger equation: the one-electron case

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    In this work we present the theoretical framework for the solution of the time-dependent Schr\"{o}dinger equation (TDSE) of atomic and molecular systems under strong electromagnetic fields with the configuration space of the electron's coordinates separated over two regions, that is regions II and IIII. In region II the solution of the TDSE is obtained by an R-matrix basis set representation of the time-dependent wavefunction. In region IIII a grid representation of the wavefunction is considered and propagation in space and time is obtained through the finite-differences method. It appears this is the first time a combination of basis set and grid methods has been put forward for tackling multi-region time-dependent problems. In both regions, a high-order explicit scheme is employed for the time propagation. While, in a purely hydrogenic system no approximation is involved due to this separation, in multi-electron systems the validity and the usefulness of the present method relies on the basic assumption of R-matrix theory, namely that beyond a certain distance (encompassing region II) a single ejected electron is distinguishable from the other electrons of the multi-electron system and evolves there (region II) effectively as a one-electron system. The method is developed in detail for single active electron systems and applied to the exemplar case of the hydrogen atom in an intense laser field.Comment: 13 pages, 6 figures, submitte

    R-matrix Floquet theory for laser-assisted electron-atom scattering

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    A new version of the R-matrix Floquet theory for laser-assisted electron-atom scattering is presented. The theory is non-perturbative and applicable to a non-relativistic many-electron atom or ion in a homogeneous linearly polarized field. It is based on the use of channel functions built from field-dressed target states, which greatly simplifies the general formalism.Comment: 18 pages, LaTeX2e, submitted to J.Phys.

    Half-Life of 14^{14}O

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    We have measured the half-life of 14^{14}O, a superallowed (0+→0+)(0^{+} \to 0^{+}) β\beta decay isotope. The 14^{14}O was produced by the 12^{12}C(3^{3}He,n)14^{14}O reaction using a carbon aerogel target. A low-energy ion beam of 14^{14}O was mass separated and implanted in a thin beryllium foil. The beta particles were counted with plastic scintillator detectors. We find t1/2=70.696±0.052t_{1/2} = 70.696\pm 0.052 s. This result is 1.5σ1.5\sigma higher than an average value from six earlier experiments, but agrees more closely with the most recent previous measurement.Comment: 10 pages, 5 figure

    Toilet talk: (Trans)Gendered negotiation of public spaces

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    Public toilet provision in the UK fails to meet the needs of cis women while trans communities are absent from current building regulations. This research explores how individuals negotiate differing positions on toilet provision and accessibility. The data was formed of online posts on Dezeen, a forum for building design professionals, and Mumsnet, a parenting forum, in response to the Ministry of Housing and Local Government ‘Technical review on increasing accessibility and provision of toilets for men and women’. Discursive Psychology was used to explore how accessibility to toilets is constructed. There is also an opportunity to explore how a discursive approach can be applied interdisciplinary with town planning and the built environment. Gender identities are situated and constructed within public toilets. Talk about refuge in public bathrooms involved the negotiation of who belonged in differing gender categories and who warranted a need for refuge. Where men are explicitly acknowledged as an issue, cis and trans women are collectively identified as requiring a safe space. Cis women are presented as a threat to trans women and other cis women who are misgendered. Discourse about toilet provision draws upon both heteronormative ideology to challenge access to trans people and others who challenge normative gender roles. Talk about toilets involves warranting ‘place-identity’ as gender identity is situated and access limited to those who are constructed as belonging

    Modal Theory of Skin Effect in Single and Multiple Turn Coils

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    The skin effect in circularly symmetric structures is formulated in terms of an integral equation, which may be solved in terms of the normal modes of the corresponding integral equation eigenvalue problem. The necessary modal functions are computed numerically, using a simple discrete model of the coil. The modal series solution easily accounts for electrical excitation of the coil as for external magnetic fields. A comparison with so-called "direct" calculation methods, as well as with published experimental results, shows that the method is capable of good accuracy, while effecting substantial economies in computation

    Ionization of hydrogen atoms by electron impact at 1eV, 0.5eV and 0.3eV above threshold

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    We present here triple differential cross sections for ionization of hydrogen atoms by electron impact at 1eV, 0.5eV and 0.3eV energy above threshold, calculated in the hyperspherical partial wave theory. The results are in very good agreement with the available semiclassical results of Deb and Crothers \cite{DC02} for these energies. With this, we are able to demonstrate that the hyperspherical partial wave theory yields good cross sections from 30 eV \cite{DPC03} down to near threshold for equal energy sharing kinematics.Comment: 6 pages, 9 figure

    A Human Torque Teno Virus Encodes a MicroRNA That Inhibits Interferon Signaling

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    Rodney P. Kincaid, James M. Burke, Jennifer C. Cox, Christopher S. Sullivan, The University of Texas at Austin, Molecular Genetics and Microbiology, Austin, Texas, United States of AmericaEthel-Michele de Villiers, Division for the Characterization of Tumorviruses, Deutsches Krebsforschungszentrum, Heidelberg, GermanyTorque teno viruses (TTVs) are a group of viruses with small, circular DNA genomes. Members of this family are thought to ubiquitously infect humans, although causal disease associations are currently lacking. At present, there is no understanding of how infection with this diverse group of viruses is so prevalent. Using a combined computational and synthetic approach, we predict and identify miRNA-coding regions in diverse human TTVs and provide evidence for TTV miRNA production in vivo. The TTV miRNAs are transcribed by RNA polymerase II, processed by Drosha and Dicer, and are active in RISC. A TTV mutant defective for miRNA production replicates as well as wild type virus genome; demonstrating that the TTV miRNA is dispensable for genome replication in a cell culture model. We demonstrate that a recombinant TTV genome is capable of expressing an exogenous miRNA, indicating the potential utility of TTV as a small RNA vector. Gene expression profiling of host cells identifies N-myc (and STAT) interactor (NMI) as a target of a TTV miRNA. NMI transcripts are directly regulated through a binding site in the 3′UTR. SiRNA knockdown of NMI contributes to a decreased response to interferon signaling. Consistent with this, we show that a TTV miRNA mediates a decreased response to IFN and increased cellular proliferation in the presence of IFN. Thus, we add Annelloviridae to the growing list of virus families that encode miRNAs, and suggest that miRNA-mediated immune evasion can contribute to the pervasiveness associated with some of these viruses.This work was supported by grants RO1AI077746 from the National Institutes of Health, RP110098 from the Cancer Prevention and Research Institute of Texas, a Burroughs Wellcome Investigators in Pathogenesis Award to CSS, a UT Austin Powers Graduate Fellowship to RPK, a UT Austin Institute for Cellular and Molecular Biology fellowship, and the DKFZ for EMdV. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Molecular BiosciencesMicrobiologyEmail: [email protected]
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