Effective Actions, Boundaries and Precision Calculations of Casimir Energies

We perform the matching required to compute the leading effective boundary contribution to the QED lagrangian in the presence of a conducting surface, once the electron is integrated out. Our result resolves a confusion in the literature concerning the interpretation of the leading such correction to the Casimir energy. It also provides a useful theoretical laboratory for brane-world calculations in which kinetic terms are generated on the brane, since a lot is known about QED near boundaries.Comment: 5 pages. revtex; Added paragraphs describing finite-conductivity effects and effects due to curvatur

Multiple Inflation, Cosmic String Networks and the String Landscape

Motivated by the string landscape we examine scenarios for which inflation is a two-step process, with a comparatively short inflationary epoch near the string scale and a longer period at a much lower energy (like the TeV scale). We quantify the number of $e$-foldings of inflation which are required to yield successful inflation within this picture. The constraints are very sensitive to the equation of state during the epoch between the two inflationary periods, as the extra-horizon modes can come back inside the horizon and become reprocessed. We find that the number of $e$-foldings during the first inflationary epoch can be as small as 12, but only if the inter-inflationary period is dominated by a network of cosmic strings (such as might be produced if the initial inflationary period is due to the brane-antibrane mechanism). In this case a further 20 $e$-foldings of inflation would be required at lower energies to solve the late universe's flatness and horizon problems.Comment: 27 pages, 6 figures; v2: refences adde

Can existing assessment tools be used to track equity in protected area management under Aichi Target 11?

Aichi Target 11 (AT11) includes the commitment of 194 governments to equitably manage protected areas (PAs) by 2020. Here we evaluate whether existing PA Management Effectiveness (PAME) and social and governance assessment tools can be used to determine if AT11 meets equity goals. We find that PAME assessment conditions are insufficiently inclusive of relevant actors and do not satisfactorily allow for a diversity of perspectives to be expressed and accounted for, both of which are essential for equitable PA management. Furthermore, none of the analysed PAME tools fully cover multidimensional equity and thus they are inadequate for assessing progress towards equitable management in PAs. The available social and governance PA assessment tools stipulate more inclusive and participatory conditions within their guidelines, and the IUCN Governance Guidelines comprehensively capture equity dimensions in PA management, but results are not comparable across sites. We conclude that available assessment tools do not provide a reliable way to track equity in PAs at global scale. The IUCN Governance Guidelines could be adjusted to achieve this goal, providing that the information collected is made globally comparable, while ensuring transparency, accountability and room for contestation, including by communities whose livelihoods are directly implicated. Ultimately, developing and deploying globally comparable measures to evaluate equity is problematic, as the process of gathering comparable data inevitably obscures information that is highly relevant to resolving equity issues at local scales. This challenge must be met, however, if nations are to achieve and report on their success at meeting AT11 by 2020. © 2018 Elsevier LtdWe thank Jens Friis Lund from the University of Copenhagen for his great support in the writing of this publication. We also thank the following for their assistance in the data collection and analysis: April Eassom, Lauren Coad, Kathryn Knights, Jonas Geldmann, Murielle Misrachi and Naomi Kingston from UNEP-WCMC, PA Solutions, University of Oxford and University of Copenhagen, Phil Franks, Kate Schreckenberg and Dilys Roe from IIED, Marc Hockings, Fiona Leverington from IUCN WCPA/University of Queensland. N.Z-C. and N.B. acknowledge the funding provided by the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 659881 to N.Z-C. and the Danish National Research Foundation for funding for the Centre for Macroecology, Evolution and Climate; grant number DNRF96 . We thank Jens Friis Lund from the University of Copenhagen for his great support in the writing of this publication. We also thank the following for their assistance in the data collection and analysis: April Eassom, Lauren Coad, Kathryn Knights, Jonas Geldmann, Murielle Misrachi and Naomi Kingston from UNEP-WCMC, PA Solutions, University of Oxford and University of Copenhagen, Phil Franks, Kate Schreckenberg and Dilys Roe from IIED, Marc Hockings, Fiona Leverington from IUCN WCPA/University of Queensland. N.Z-C. and N.B. acknowledge the funding provided by the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 659881 to N.Z-C. and the Danish National Research Foundation for funding for the Centre for Macroecology, Evolution and Climate; grant number DNRF96

Atomic data from the IRON Project. I. Electron-impact scattering of Fe17+ using <I>R</I>-matrix theory with intermediate coupling

We present results for electron-impact excitation of F-like Fe calculated using R-matrix theory where an intermediate-coupling frame transformation (ICFT) is used to obtain level-resolved collision strengths. Two such calculations are performed, the first expands the target using 2s2 2p5, 2s 2p6, 2s2 2p4 3l, 2s 2p5 3l, and 2p6 3l configurations while the second calculation includes the 2s2 2p4 4l, 2s 2p5 4l, and 2p6 4l configurations as well. The effect of the additional structure in the latter calculation on the n=3 resonances is explored and compared with previous calculations. We find strong resonant enhancement of the effective collision strengths to the 2s2 2p4 3s levels. A comparison with a Chandra X-ray observation of Capella shows that the n=4 R-matrix calculation leads to good agreement with observation</p

Improving together : collaboration needs to start with regulators

The regulatory landscape in the UK is changing again. From 1 April 2019 NHS England and NHS Improvement became what is effectively a single organisation with far reaching responsibility for the oversight of the system. The structural features of this change, which will eventually require legislative reform, have been widely debated, not least by those affected by plans for a collaborative approach to improvement in the NHS.12 But there has been less discussion about the style and approach to regulation that might be best suited to drive improvement in the NHS as set out in the long term plan.3 We contend that a major change is required in the way the system interacts with service providers if we are to be successful in developing a new service model for the 21st century

Inflation in Realistic D-Brane Models

We find successful models of D-brane/anti-brane inflation within a string context. We work within the GKP-KKLT class of type IIB string vacua for which many moduli are stabilized through fluxes, as recently modified to include `realistic' orbifold sectors containing standard-model type particles. We allow all moduli to roll when searching for inflationary solutions and find that inflation is not generic inasmuch as special choices must be made for the parameters describing the vacuum. But given these choices inflation can occur for a reasonably wide range of initial conditions for the brane and antibrane. We find that D-terms associated with the orbifold blowing-up modes play an important role in the inflationary dynamics. Since the models contain a standard-model-like sector after inflation, they open up the possibility of addressing reheating issues. We calculate predictions for the CMB temperature fluctuations and find that these can be consistent with observations, but are generically not deep within the scale-invariant regime and so can allow appreciable values for $dn_s/d\ln k$ as well as predicting a potentially observable gravity-wave signal. It is also possible to generate some admixture of isocurvature fluctuations.Comment: 39 pages, 21 figures; added references; identified parameters combining successful inflation with strong warping, as needed for consistency of the approximation

Electron-Ion Recombination Rate Coefficients and Photoionization Cross Sections for Astrophysically Abundant Elements. V. Relativistic calculations for Fe XXIV and Fe XXV for X-ray modeling

Photoionization and recombination cross sections and rate coefficients are calculated for Li-like Fe XXIV and He-like Fe XXV using the Breit-Pauli R-matrix (BPRM) method. A complete set of total and level-specific parameters is obtained to enable X-ray photoionization and spectral modeling. The ab initio calculations for the unified (e + ion) recombination rate coefficients include both the non-resonant and the resonant recombination (radiative and di-electronic recombination, RR and DR, respectively) for (e + Fe XXV) -> Fe XXIV and (e + Fe XXVI) -> Fe XXV. The level specific rates are computed for all fine structure levels up to n = 10, enabling accurate computation of recombination-cascade matrices and effective rates for the X-ray lines. The total recombination rate coefficients for both Fe XXIV and Fe XXV differ considerably, by several factors, from the sum of RR and DR rates currently used to compute ionization fractions in astrophysical models. As the photoionization/recombination calculations are carried out using an identical eigenfunction expansion, the cross sections for both processes are theoretically self-consistent; the overall uncertainty is estimated to be about 10-20%. All data for Fe XXIV and Fe XXV (and also for H-like Fe XXVI, included for completeness) are available electronically.Comment: 31 pages, 10fug

Warped Tachyonic Inflation in Type IIB Flux Compactifications and the Open-String Completeness Conjecture

We consider a cosmological scenario within the KKLT framework for moduli stabilization in string theory. The universal open string tachyon of decaying non-BPS D-brane configurations is proposed to drive eternal topological inflation. Flux-induced `warping' can provide the small slow-roll parameters needed for successful inflation. Constraints on the parameter space leading to sufficient number of e-folds, exit from inflation, density perturbations and stabilization of the Kahler modulus are investigated. The conditions are difficult to satisfy in Klebanov-Strassler throats but can be satisfied in T^3 fibrations and other generic Calabi-Yau manifolds. This requires large volume and magnetic fluxes on the D-brane. The end of inflation may or may not lead to cosmic strings depending on the original non-BPS configuration. A careful investigation of initial conditions leading to a phenomenologically viable model for inflation is carried out. The initial conditions are chosen on the basis of Sen's open string completeness conjecture. We find time symmetrical bounce solutions without initial singularities for k=1 FRW models which are correlated with an inflationary period. Singular big-bang/big-crunch solutions also exist but do not lead to inflation. There is an intriguing correlation between having an inflationary universe in 4 dimensions and 6 compact dimensions or a big-crunch singularity and decompactification.Comment: 43 pages, 9 figures. v3: Typos correcte

Directional wetting in anisotropic inverse opals

Porous materials display interesting transport phenomena due to the restricted motion of fluids within the nano- to micro-scale voids. Here, we investigate how liquid wetting in highly ordered inverse opals is affected by anisotropy in pore geometry. We compare samples with different degrees of pore asphericity and find different wetting patterns depending on the pore shape. Highly anisotropic structures are infiltrated more easily than their isotropic counterparts. Further, the wetting of anisotropic inverse opals is directional, with liquids filling from the side more easily. This effect is supported by percolation simulations as well as direct observations of wetting using time-resolved optical microscopy

Warped Reheating in Multi-Throat Brane Inflation

We investigate in some quantitative details the viability of reheating in multi-throat brane inflationary scenarios by estimating and comparing the time scales for the various processes involved. We also calculate within perturbative string theory the decay rate of excited closed strings into KK modes and compare with that of their decay into gravitons; we find that in the inflationary throat the former is preferred. We also find that over a small but reasonable range of parameters of the background geometry, these KK modes will preferably tunnel to another throat (possibly containing the Standard Model) instead of decaying to gravitons due largely to their suppressed coupling to the bulk gravitons. Once tunneled, the same suppressed coupling to the gravitons again allows them to reheat the Standard Model efficiently. We also consider the effects of adding more throats to the system and find that for extra throats with small warping, reheating still seems viable.Comment: 29 pages, 4 figures, discussions on closed string decay expanded, references adde