A New Species of Bufo (Anura: Bufonidae) From Africa's Dry Savannas

Texas Memorial Museu

Electron and phonon interactions and transport in the ultrahigh-temperature ceramic ZrC

We have simulated the ultrahigh-temperature ceramic zirconium carbide (ZrC) in order to predict electron and phonon scattering properties, including lifetimes and transport. Our predictions of heat and charge conductivity, which extend to 3000 K, are relevant to extreme-temperature applications of ZrC. Mechanisms are identified on a first-principles basis that considerably enhance or suppress heat transport at high temperature, including strain, anharmonic phonon renormalization, and four-phonon scattering. The extent to which boundary confinement and isotope scattering effects lower thermal conductivity is predicted

Vanishing Cosmological Constant by Gravitino-Dressed Compactification of 11D Supergravity

We consider compactifications induced by the gravitino field of eleven dimensional supergravity. Such compactifications are not trivial in the sense that the gravitino profiles are not related to pure bosonic ones by means of a supersymmetry transformation. The basic property of such backgrounds is that they admit $\psi$-torsion although they have vanishing Riemann tensor. Thus, these backgrounds may be considered also as solutions of the teleparallel formulation of supergravity. We construct two classes of solutions, one with both antisymmetric three-form field, gravity and gravitino and one with only gravity and gravitino. In these classes of solutions, the internal space is a parallelized compact manifold, so that it does not inherit any cosmological constant to the external spacetime. The latter turns out to be flat Minkowski in the maximally symmetric case. The elimination of the cosmological constant in the spontaneously compactified supergravity seems to be a generic property based on the trading of the cosmological constant for parallelizing torsion.Comment: 17 pages, no figure

Hippocampal Amnesia Impairs All Manner of Relational Memory

Relational memory theory holds that the hippocampus supports, and amnesia following hippocampal damage impairs, memory for all manner of relations. Unfortunately, many studies of hippocampal-dependent memory have either examined only a single type of relational memory or conflated multiple kinds of relations. The experiments reported here employed a procedure in which each of several kinds of relational memory (spatial, associative, and sequential) could be tested separately using the same materials. In Experiment 1, performance of amnesic patients with medial temporal lobe (MTL) damage was assessed on memory for the three types of relations as well as for items. Compared to the performance of matched comparison participants, amnesic patients were impaired on all three relational tasks. But for those patients whose MTL damage was limited to the hippocampus, performance was relatively preserved on item memory as compared to relational memory, although still lower than that of comparison participants. In Experiment 2, study exposure was reduced for comparison participants, matching their item memory to the amnesic patients in Experiment 1. Relational memory performance of comparison subjects was well above amnesic patient levels, showing the disproportionate dependence of all three relational memory performances on the integrity of the hippocampus. Correlational analyses of the various task performances of comparison participants and of college-age participants showed that our measures of item memory were not influenced significantly by memory for associations among the items

A Warped Supersymmetric Standard Model

We study the breaking of supersymmetry in five-dimensional (5d) warped spaces, using the Randall-Sundrum model as a prototype. In particular, we present a supersymmetry-breaking mechanism which has a geometrical origin, and consists of imposing different boundary conditions between the fermions and bosons living in the 5d bulk. The scale of supersymmetry breaking is exponentially small due to the warp factor of the AdS metric. We apply this mechanism to a supersymmetric standard model where supersymmetry breaking is transmitted through the AdS bulk to matter fields confined on the Planck-brane. This leads to a predictable superparticle mass spectrum where the gravitino mass is $10^{-3}$eV and scalar particles receive masses at the one-loop level via bulk gauge interactions. We calculate the mass spectrum in full detail using the 5d AdS propagators. The AdS/CFT correspondence suggests that our 5d warped model is dual to the ordinary 4d MSSM with a strongly coupled CFT sector responsible for the breaking of supersymmetry.Comment: 22 pages, LaTeX; v2: references and more comments on AdS/CFT correspondence adde

Discrimination of Methionine Sulfoxide and Sulfone by Human Neutrophil Elastase

Human neutrophil elastase (HNE) is a uniquely destructive serine protease with the ability to unleash a wave of proteolytic activity by destroying the inhibitors of other proteases. Although this phenomenon forms an important part of the innate immune response to invading pathogens, it is responsible for the collateral host tissue damage observed in chronic conditions such as chronic obstructive pulmonary disease (COPD), and in more acute disorders such as the lung injuries associated with COVID-19 infection. Previously, a combinatorially selected activity-based probe revealed an unexpected substrate preference for oxidised methionine, which suggests a link to oxida-tive pathogen clearance by neutrophils. Here we use oxidised model substrates and inhibitors to confirm this observation and to show that neutrophil elastase is specifically selective for the di-oxygenated methionine sulfone rather than the mono-oxygenated methionine sulfoxide. We also posit a critical role for ordered solvent in the mechanism of HNE discrimination between the two oxidised forms methionine residue. Preference for the sulfone form of oxidised methionine is especially significant. While both host and pathogens have the ability to reduce methionine sulfoxide back to methionine, a biological pathway to reduce methionine sulfone is not known. Taken to-gether, these data suggest that the oxidative activity of neutrophils may create rapidly cleaved elas-tase “super substrates” that directly damage tissue, while initiating a cycle of neutrophil oxidation that increases elastase tissue damage and further neutrophil recruitment

Spherical and planar three-dimensional anti-de Sitter black holes

The technique of dimensional reduction was used in a recent paper (Zanchin et al, Phys. Rev. D66, 064022,(2002)) where a three-dimensional (3D) Einstein-Maxwell-Dilaton theory was built from the usual four-dimensional (4D) Einstein-Maxwell-Hilbert action for general relativity. Starting from a class of 4D toroidal black holes in asymptotically anti-de Sitter (AdS) spacetimes several 3D black holes were obtained and studied in such a context. In the present work we choose a particular case of the 3D action which presents Maxwell field, dilaton field and an extra scalar field, besides gravity field and a negative cosmological constant, and obtain new 3D static black hole solutions whose horizons may have spherical or planar topology. We show that there is a 3D static spherically symmetric solution analogous to the 4D Reissner-Nordstr\"om-AdS black hole, and obtain other new 3D black holes with planar topology. From the static spherical solutions, new rotating 3D black holes are also obtained and analyzed in some detail.Comment: 27 pages, uses "iopclass" files (Latex2e

Flat-brane Compactifications in Supergravity Induced by Scalars

We discuss flat compactifications of supergravities in diverse dimensions in the presence of branes. The compactification is induced by the scalar fields of supergravity and it is such that there is no relic cosmological constant on the brane, rendering this way the latter flat. We discuss in particular the D=4, $N=2,4$ and D=8, N=1 supergravities with $n=1,2,3$ vector multiplets where the scalar manifolds are Grassmannian cosets of the form $SO(2,n)/SO(2)\times SO(n)$. By introducing branes at certain points in the transverse space, finite energy solutions to the field equations are constructed. Some of the solutions we present may be interpreted as intersecting branes.Comment: 26 page

Holographic GB gravity in arbitrary dimensions

We study the properties of the holographic CFT dual to Gauss-Bonnet gravity in general $D \ge 5$ dimensions. We establish the AdS/CFT dictionary and in particular relate the couplings of the gravitational theory to the universal couplings arising in correlators of the stress tensor of the dual CFT. This allows us to examine constraints on the gravitational couplings by demanding consistency of the CFT. In particular, one can demand positive energy fluxes in scattering processes or the causal propagation of fluctuations. We also examine the holographic hydrodynamics, commenting on the shear viscosity as well as the relaxation time. The latter allows us to consider causality constraints arising from the second-order truncated theory of hydrodynamics.Comment: 48 pages, 9 figures. v2: New discussion on free fields in subsection 3.3 and new appendix B on conformal tensor fields. Added comments on the relation between the central charge appearing in the two-point function and the "central charge" characterizing the entropy density in the discussion. References adde

Supplemental Income: British newspaper colour supplements in the 1960s

The introduction of colour supplements by three ‘quality’ newspapers during the 1960s was a key development in the British press during the decade, and was described by the editor of the Sunday Times as ‘perhaps the most successful single innovation in post-war journalism’. This article provides an overview of the advent of the colour supplements, explaining why they emerged when they did and developed in the manner they did, and exploring some of the difficulties and issues that attended their arrival. The article also demonstrates that sections of the British press were capable of taking advantage of changes in print and advertising culture brought about by the arrival of the post-war consumer society. However, the term ‘colour supplement’ became pejorative shorthand for the perceived vacuity of this new society, in part because of the tension that existed between the editorial and advertising content of these modish new publications. Consequently, the success of the colour supplement experiment was not universally celebrated