Effective Actions for Heterotic M-Theory

We discuss the moduli space approximation for heterotic M-theory, both for the minimal case of two boundary branes only, and when a bulk brane is included. The resulting effective actions may be used to describe the cosmological dynamics in the regime where the branes are moving slowly, away from singularities. We make use of the recently derived colliding branes solution to determine the global structure of moduli space, finding a boundary at which the trajectories undergo a hard wall reflection. This has important consequences for the allowed moduli space trajectories, and for the behaviour of cosmological perturbations in the model.Comment: 21 pages, 4 figures. References added and some discussions clarifie

Modelling stellar coronal magnetic fields

Our understanding of the structure and dynamics of stellar coronae has changed dramatically with the availability of surface maps of both star spots and also magnetic field vectors. Magnetic field extrapolations from these surface maps reveal surprising coronal structures for stars whose masses and hence internal structures and dynamo modes may be very different from that of the Sun. Crucial factors are the fraction of open magnetic flux (which determines the spin-down rate for the star as it ages) and the location and plasma density of closed-field regions, which determine the X-ray and radio emission properties. There has been recent progress in modelling stellar coronae, in particular the relative contributions of the field detected in the bright surface regions and the field that may be hidden in the dark star spots. For the Sun, the relationship between the field in the spots and the large scale field is well studied over the solar cycle. It appears, however, that other stars can show a very different relationship.Comment: 6pages, 4 figure

Numerical modelling of two-way reinforced concrete slabs in fire

This paper describes numerical modelling of the fire behaviour of two-way reinforced concrete slabs using a special purpose non-linear finite-element program, SAFIR. Several two-way reinforced concrete and composite steel-concrete slabs are tested under exposure to the ISO standard fire in order to validate the shell finite element in the SAFIR program. The modelling results showed agreement with the fire tests and demonstrate that the SAFIR shell element can be used to predict tensile membrane behaviour of two-way reinforced concrete slabs in fire conditions. The analyses show that two-way slabs have excellent fire resistance if they deform in double curvature and develop tensile membrane action. (C) 2004 Elsevier Ltd. All rights reserved

Moduli of Langlands Parameters

Let $F$ be a nonarchimedean local field of residue characteristic $p$, let $\hat{G}$ be a split connected reductive group over $\mathbb{Z}[1/p]$ with an action of $W_F$, and let $^LG$ denote the semidirect product $\hat{G}\rtimes W_F$. We construct a moduli space of Langlands parameters $W_F \to {^LG}$, and show that it is locally of finite type and flat over $\mathbb{Z}[1/p]$, and that it is a reduced local complete intersection. We give parameterizations of the connected components of this space over algebraically closed fields of characteristic zero and characteristic $\ell\neq p$, as well as of the components over $\overline{\mathbb{Z}}_{\ell}$ and (conjecturally) over $\overline{\mathbb{Z}}[1/p]$. Finally we study the functions on this space that are invariant under conjugation by $\hat{G}$ (or, equivalently, the GIT quotient by $\hat{G}$) and give a complete description of this ring of functions after inverting an explicit finite set of primes depending only on $^LG$.Comment: 79 page

A comparison of HPV DNA testing and liquid based cytology over three rounds of primary cervical screening: extended follow up in the ARTISTIC trial.

BACKGROUND: The additional sensitivity of HPV testing compared with cytology could permit extended cervical screening intervals. We wished to determine, through a further (third) round of screening in the ARTISTIC trial, the protection provided by a negative baseline HPV screen compared with that of cytology over a 6 year period. METHODS: Cumulative rates of CIN2 or worse (CIN2+) and CIN3 or worse (CIN3+) were correlated with baseline HPV status and cytology. HPV was detected using the Hybrid Capture 2 (Qiagen) assay for high risk types and genotyped using the Linear Array (Roche) and Papillocheck (Greiner) assays. LBC was performed using ThinPrep (Hologic). FINDINGS: Round 3 included 8,873 women of whom 6,337 had been screened in both rounds 1 and 2 and 2,536 had not been screened since round 1. The median duration of follow-up was 72.7 months. The cumulative rate of CIN2+ over three rounds was 3.88% (95%CI 3.59%, 4.17%) overall; 2.39% in round 1, 0.78% in round 2 and 0.74% in round 3. Cumulative rates by baseline status were 20.53% (95%CI 19.04%, 22.08%) for abnormal cytology, 20.12% (95%CI 18.68%, 21.61%) for HPV detection, 1.41% (95%CI 1.19%, 1.65%) for negative cytology and 0.87% (95%CI 0.70%, 1.06%) for a negative HPV test. In HPV negative women aged over 50 the cumulative rate was 0.16% (95%CI 0.07%, 0.34%). Women who were HPV positive/cytology negative at entry had a cumulative CIN2+ rate of 7.73% (95%CI 6.29%, 9.36%) over 6 years, twice the overall rate. INTERPRETATION: A negative HPV test was significantly more protective than normal cytology over three rounds. The findings of this extension of ARTISTIC suggest that the screening interval could be extended to 6 years if HPV testing replaced cytology as the primary screening test

Bilingualism and executive functioning in children born very low birth weight and normal birth weight

Research has documented an advantage on executive functioning in bilingual compared to monolingual children, suggesting that bilingual children may develop inhibitory control earlier than their monolingual peers. There are no known studies examining the differences between monolingual and bilingual children who were born very low birth weight (VLBW). Children born VLBW are at greater risk for difficulties with attention and inhibition. Executive functioning abilities were measured at 3-4 years and at 5-7 years. Caregivers reported sociodemographic information. Bilingualism was measured by self-report and observation of unstructured mother-child play. Executive functioning abilities were measured using the Bear Dragon (inhibition and working memory 3-4 years), Memory for Location 2 (working memory 3-4 years), Gift Delay (inhibition 3-4 & 5-7 years), WJ-III Memory for Words (working memory 3-4 & 5-7 years), Color Form (inhibition and task switching 5-7 years), and the DCCS (inhibition and task switching 5-7 years). Children born normal birth weight (NBW) performed significantly better on tasks involving working memory (3-4 years), and inhibition (5-7years). Monolingual children born NBW performed better on tasks of working memory (3-4 years) and inhibition (5-7 years) compared to bilingual children born VLBW. Modest evidence for a bilingual (parent reported but not observational) advantage on one of three inhibition tasks (Gift Delay) emerged at school age (5-7 years). Children born NBW performed better on executive functioning measures beginning at the preschool age (3-4 years). Evidence for developmental differences between these groups helps to provide a broader understanding of the development of early executive processes

Extended-Synaptotagmin-2 Mediates FGF Receptor Endocytosis and ERK Activation In Vivo

SummaryTargeting of activated plasma membrane receptors to endocytic pathways is important in determining the outcome of growth factor signaling. However, the molecular mechanisms are still poorly understood. Here, we show that the synaptotagmin-related membrane protein E-Syt2 is essential for rapid endocytosis of the activated FGF receptor and for functional signal transduction during Xenopus development. E-Syt2 depletion prevents an early phase of activated FGF receptor endocytosis that we show is required for ERK activation and the induction of the mesoderm. E-Syt2 interacts selectively with the activated FGF receptor and with Adaptin-2, and is required upstream of Ras activation and of receptor autophosphorylation for ERK activation and the induction of the mesodermal marker Xbra. The data identify E-Syt2 as an endocytic adaptor for the clathrin-mediated pathway whose function is conserved in human and suggest a broader role for the E-Syt subfamily in growth factor signaling

Colliding Branes in Heterotic M-theory

We study the collision of two flat, parallel end-of-the-world branes in heterotic M-theory. By insisting that there is no divergence in the Riemann curvature as the collision approaches, we are able to single out a unique solution possessing the local geometry of (2d compactified Milne)/Z_2 x R_3, times a finite-volume Calabi-Yau manifold in the vicinity of the collision. At a finite time before and after the collision, a second type of singularity appears momentarily on the negative-tension brane, representing its bouncing off a zero of the bulk warp factor. We find this singularity to be remarkably mild and easily regularised. The various different cosmological solutions to heterotic M-theory previously found by other authors are shown to merely represent different portions of a unique flat cosmological solution to heterotic M-theory.Comment: 29 pp, 4 figs; Appendix B revised to include junction condition for scala

The Beta Problem: A Study of Abell 262

We present an investigation of the dynamical state of the cluster A262. Existing optical line of sight velocities for select cluster galaxies have been augmented by new data obtained with the Automated Multi-Object Spectrograph at Lick Observatory. We find evidence for a virialized early-type population distinct from a late-type population infalling from the Pisces-Perseus supercluster ridge. We also report on a tertiary population of low luminosity galaxies whose velocity dispersion distinguishes them from both the early and late-type galaxies. We supplement our investigation with an analysis of archival X-ray data. A temperature is determined using ASCA GIS data and a gas profile is derived from ROSAT HRI data. The increased statistics of our sample results in a picture of A262 with significant differences from earlier work. A previously proposed solution to the "beta-problem" in A262 in which the gas temperature is significantly higher than the galaxy temperature is shown to result from using too low a velocity dispersion for the early-type galaxies. Our data present a consistent picture of A262 in which there is no "beta-problem", and the gas and galaxy temperature are roughly comparable. There is no longer any requirement for extensive galaxy-gas feedback to drastically overheat the gas with respect to the galaxies. We also demonstrate that entropy-floor models can explain the recent discovery that the beta values determined by cluster gas and the cluster core radii are correlated.Comment: 31 pages, 14 figures, AAS LaTeX v5.0, Encapsulated Postscript figures, to be published in The Astrophysical Journa