Gravitons and Lightcone Fluctuations II: Correlation Functions

A model of a fluctuating lightcone due to a bath of gravitons is further investigated. The flight times of photons between a source and a detector may be either longer or shorter than the light propagation time in the background classical spacetime, and will form a Gaussian distribution centered around the classical flight time. However, a pair of photons emitted in rapid succession will tend to have correlated flight times. We derive and discuss a correlation function which describes this effect. This enables us to understand more fully the operational significance of a fluctuating lightcone. Our results may be combined with observational data on pulsar timing to place some constraints on the quantum state of cosmological gravitons.Comment: 16 pages and two figures, uses eps

The exact three-dimensional half-shell t-matrix for a sharply cut-off Coulomb potential in the screening limit

The three-dimensional half-shell t-matrix for a sharply cut-off Coulomb potential is analytically derived together with its asymptotic form without reference to partial wave expansion. The numerical solutions of the three-dimensional Lippmann-Schwinger equation for increasing cut-off radii provide half-shell t-matrices which are in quite a good agreement with the asymptotic values.Comment: 15 pages, 4 eps figure

NICE guidance on long-term sickness and incapacity

Long-term sickness absence and incapacity benefits (disability pension) rates have increased across industrialised countries. Effective measures are needed to support return to work. The recommendations of this guidance were informed by the most appropriate available evidence of effectiveness and cost-effectiveness. Public health evidence was provided by research using a variety of study designs that attempted to determine the outcome of a particular intervention by evaluating status before and after the intervention had been effected, and was not limited to randomised control trials. Where the evidence base was depleted or underdeveloped, expert witnesses were called to give their opinion on the best available evidence and emerging interventions. The process enabled challenge and contestability from stakeholder groups at different points as the guidance was developed. Forty-five heterogeneous studies were included in the review of interventions to reduce long-term sickness absence and transitions from short-term to long-term absence (mainly covering the former and also mainly examining musculoskeletal conditions). The analysis of evidence was restricted to descriptive synthesis. Three general themes emerged from an analysis of the studies that were more likely to report positive results: early interventions; multidisciplinary approaches; and interventions with a workplace component. Two further reviews were undertaken, one on interventions to reduce the re-occurrence of sickness absence, which identified seven studies on lower back pain, and concluded that early intervention and direct workplace input are important factors. The final evidence review focused on six studies of interventions for those in receipt of incapacity benefit. The evidence was that work-focused interviews coupled with access to tailored support are effective and cost-effective interventions. Practitioners should consider the impact of interventions and management options on work ability for patients of working age. Work ability should be considered a key outcome for future intervention studies

Radiation from the non-extremal fuzzball

The fuzzball proposal says that the information of the black hole state is distributed throughout the interior of the horizon in a `quantum fuzz'. There are special microstates where in the dual CFT we have `many excitations in the same state'; these are described by regular classical geometries without horizons. Jejjala et.al constructed non-extremal regular geometries of this type. Cardoso et. al then found that these geometries had a classical instability. In this paper we show that the energy radiated through the unstable modes is exactly the Hawking radiation for these microstates. We do this by (i) starting with the semiclassical Hawking radiation rate (ii) using it to find the emission vertex in the CFT (iii) replacing the Boltzman distributions of the generic CFT state with the ones describing the microstate of interest (iv) observing that the emission now reproduces the classical instability. Because the CFT has `many excitations in the same state' we get the physics of a Bose-Einstein condensate rather than a thermal gas, and the usually slow Hawking emission increases, by Bose enhancement, to a classically radiated field. This system therefore provides a complete gravity description of information-carrying radiation from a special microstate of the nonextremal hole.Comment: corrected typo

On Infrared Effects in de~Sitter Background

We have estimated higher order quantum gravity corrections to de~Sitter spacetime. Our results suggest that, while the classical spacetime metric may be distorted by the graviton self-interactions, the corrections are relatively weaker than previously thought, possibly growing like a power rather than exponentially in time.Comment: 17, UM-TH-94-11, (1 postscript fig. at end

Constituting monetary conservatives via the 'savings habit': New Labour and the British housing market bubble

The ongoing world credit crunch might well kill off the most recent bubble dynamics in the British housing market by driving prices systematically downwards from their 2007 peak. Nonetheless, the experience of that bubble still warrants analytical attention. The Labour Government might not have been responsible for consciously creating it, but it has certainly grasped the opportunities the bubble has provided in an attempt to enforce a process of agential change at the heart of the British economy. The key issue in this respect is the way in which the Government has challenged the legitimacy of passive welfare receipts in favour of establishing a welfare system based on incorporating the individual into an active asset-holding society. The housing market has taken on new political significance as a means for individuals first to acquire assets and then to accumulate wealth on the back of asset ownership. The ensuing integration of the housing market into an increasingly reconfigured welfare system has permeated into the politics of everyday life. It has been consistent with individuals remaking their political subjectivities in line with preferences for the type of conservative monetary policies that typically keep house price bubbles inflated

The GALFA-HI Compact Cloud Catalog

We present a catalog of 1964 isolated, compact neutral hydrogen clouds from the Galactic Arecibo L-Band Feed Array Survey Data Release One (GALFA-HI DR1). The clouds were identified by a custom machine-vision algorithm utilizing Difference of Gaussian kernels to search for clouds smaller than 20'. The clouds have velocities typically between |VLSR| = 20-400 km/s, linewidths of 2.5-35 km/s, and column densities ranging from 1 - 35 x 10^18 cm^-2. The distances to the clouds in this catalog may cover several orders of magnitude, so the masses may range from less than a Solar mass for clouds within the Galactic disc, to greater than 10^4 Solar Masses for HVCs at the tip of the Magellanic Stream. To search for trends, we separate the catalog into five populations based on position, velocity, and linewidth: high velocity clouds (HVCs); galaxy candidates; cold low velocity clouds (LVCs); warm, low positive-velocity clouds in the third Galactic Quadrant; and the remaining warm LVCs. The observed HVCs are found to be associated with previously-identified HVC complexes. We do not observe a large population of isolated clouds at high velocities as some models predict. We see evidence for distinct histories at low velocities in detecting populations of clouds corotating with the Galactic disc and a set of clouds that is not corotating.Comment: 34 Pages, 9 Figures, published in ApJ (2012, ApJ, 758, 44), this version has the corrected fluxes and corresponding flux histogram and masse

The Relation of Diabetes, Impaired Fasting Blood Glucose, and Insulin Resistance to Left Ventricular Structure and Function in African Americans: The Jackson Heart Study

OBJECTIVE We assessed the relation of diabetes and insulin resistance (IR) on left ventricular (LV) structure and function in African Americans. RESEARCH DESIGN AND METHODS Among those receiving echocardiograms in cycle 1 of the Jackson Heart Study, we assessed the sex-specific relation of fasting blood glucose (FBG), diabetes, and IR to LV structure and function, adjusting for age, systolic blood pressure, antihypertensive medications, and BMI. RESULTS Among 2,399 participants, LV mass index (Pwomen = 0.0002 and Pmen = 0.02), posterior wall thickness (Pwomen = 0.01 and Pmen = 0.05), and interventricular septal wall thickness (Pwomen = 0.01) were related to FBG categories. Among those with normal FBG and no diabetes, concentric remodeling and low ejection fraction in women and LV mass index and posterior wall thickness in men were related to IR. CONCLUSIONS In the largest study of its kind in a community-based cohort of African Americans, we found a relation of FBG category and IR to LV structure and function

Two alternative methods for the retrieval of somatic cell populations from the mouse ovary

Many modern techniques employed to uncover the molecular fundamentals underlying biological processes require dissociated cells as their starting point/substrate. Investigations into ovarian endocrinology or folliculogenesis therefore necessitate robust protocols for dissociating the ovary into its constituent cell populations. While in the mouse, methods to obtain individual, mature follicles are well-established, the separation and isolation of single cells of all types from early mouse follicles, including somatic cells, has been more challenging. Herein we present two methods for the isolation of somatic cells in the ovary. These methods are suitable for a range of applications relating to the study of folliculogenesis and mouse ovarian development. First, an enzymatic dissociation utilising collagenase and a temporary, primary cell culture step using neonatal mouse ovaries which yields large quantities of granulosa cells from primordial, activating, and primary follicles. Second, a rapid papain dissociation resulting in a high viability single cell suspension of ovarian somatic cells in less than an hour, which can be applied from embryonic to adult ovarian samples. Collectively these protocols can be applied to a broad array of investigations with unique advantages and benefits pertaining to both