NNLO Corrections to the Polarized Drell-Yan Coefficient Function

We present the full next-to-next-to-leading order (NNLO) corrections to the coefficient function for the polarized cross section $d \Delta\sigma/d Q$ of the Drell-Yan process. We study the effect of these corrections on the process $p+p\to l^+l^-+`X'$ at an C.M. energy $\sqrt{S}=200 GeV$. All QCD partonic subprocesses have been included provided the lepton pair is created by a virtual photon, which is a valid approximation for a lepton pair invariant mass $Q<50 GeV$. For this reaction the dominant subprocess is given by $q+\bar q\to \gamma^*+`X'$ and its higher order corrections so that it provides us with an excellent tool to measure the polarized sea-quark densities.Comment: 5 pages, 5 figures, 7th DESY Workshop on Elementary Particle Theory, Loops and Legs in Quantum Field Theory, Zinnowitz, Germany, April 25-30, 200

Exploring what lies behind public preferences for avoiding health losses caused by lapses in healthcare safety and patient lifestyle choices

© 2013 Singh et al.; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0),which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.This article has been made available through the Brunel Open Access Publishing Fund.Background: Although many studies have identified public preferences for prioritising health care interventions based on characteristics of recipient or care, very few of them have examined the reasons for the stated preferences. We conducted an on-line person trade-off (PTO) study (N=1030) to investigate whether the public attach a premium to the avoidance of ill health associated with alternative types of responsibilities: lapses in healthcare safety, those caused by individual action or lifestyle choice; or genetic conditions. We found that the public gave higher priority to prevention of harm in a hospital setting such as preventing hospital associated infections than genetic disorder but drug administration errors were valued similar to genetic disorders. Prevention of staff injuries, lifestyle diseases and sports injuries, were given lower priority. In this paper we aim to understand the reasoning behind the responses by analysing comments provided by respondents to the PTO questions. Method: A majority of the respondents who participated in the survey provided brief comments explaining preferences in free text responses following PTO questions. This qualitative data was transformed into explicit codes conveying similar meanings. An overall coding framework was developed and a reliability test was carried out. Recurrent patterns were identified in each preference group. Comments which challenged the assumptions of hypothetical scenarios were also investigated. Results: NHS causation of illness and a duty of care were the most cited reasons to prioritise lapses in healthcare safety. Personal responsibility dominated responses for lifestyle related contexts, and many respondents mentioned that health loss was the result of the individual’s choice to engage in risky behaviour. A small proportion of responses questioned the assumptions underlying the PTO questions. However excluding these from the main analysis did not affect the conclusions. Conclusion: Although some responses indicated misunderstanding or rejection of assumptions we put forward, the results were still robust. The reasons put forward for responses differed between comparisons but responsibility was the most frequently cited. Most preference elicitation studies only focus on eliciting numerical valuations but allowing for qualitative data can augment understanding of preferences as well as verifying results.EPSRC through the MATCH programme(EP/F063822/1 and EP/G012393/1) and HERG within Brunel University

Circular Polarization Induced by Scintillation in a Magnetized Medium

A new theory is presented for the development of circular polarization as radio waves propagate through the turbulent, birefringent interstellar medium. The fourth order moments of the wavefield are calculated and it is shown that unpolarized incident radiation develops a nonzero variance in circular polarization. A magnetized turbulent medium causes the Stokes parameters to scintillate in a non-identical manner. A specific model for this effect is developed for the case of density fluctuations in a uniform magnetic field.Comment: 16 pages, 1 figure, Phys. Rev. E, accepte

Simulating the Clamped Tapered Beam Specimen Under Quasi-Static and Fatigue Loading Using Floating Node Method

As part of the NASA Advanced Composites Project (ACP), a sub-element has been designed to provide validation data for progressive damage analysis models. The clamped tapered beam is a cross-ply laminated composite specimen designed to validate the simulation of the onset of matrix cracks and their interaction with delaminations, including delamination migration. A tapered geometry was used to localize the first damage occurrence in the tapered region, without prescribing an initial crack. The boundary and loading conditions were chosen to favor delamination growth and subsequent migration after the first damage occurrence. The typical sequence of events consists of a matrix crack located at the tapered region, leading to delamination onset, followed by delamination growth and subsequent delamination migration to a different interface via a dominant matrix crack. The Clamped Tapered Beam (CTB) was tested in both quasi-static and fatigue regimes. The results obtained are used in this study to assess and validate a methodology based on the Floating Node Method (FNM) implemented as an Extended Interface Element. In this methodology, quasi-static and fatigue damage formation and development are modeled by combining FNM to represent crack networks, with Directional Cohesive Zone Elements (DCZE) and Virtual Crack Closure Technique (VCCT), respectively. Qualitatively, the methodology is capable of predicting the sequence of events and overall failure morphology. Quantitatively, the simulation results generally bound the experimental data, based on the range of the characterization data used. In this paper, the results from quasi static and fatigue simulations are compared and correlated with experimental data

A prospective, randomised, double-blind, double-dummy, placebo-controlled trial to assess the respiratory effects of buprenorphine versus morphine in anaesthetised patients

Despite its long history and widespread use, some questions remain over buprenorphine’s respiratory safety profile. This study investigated respiratory depression and potential reversibility by naloxone at two buprenorphine doses, of which the intramuscularly administered dose was designed to achieve the plasma concentration range seen with transdermal delivery. The buprenorphine doses were compared to morphine administered intravenously. The IM route was proposed to avoid the characteristic high peak seen after IV bolus injection, to achieve a slow-rising plasma concentration which plateaus at five minutes, The selected intramuscular buprenorphine dose (0.85 mcg/kg) was chosen to achieve a similar plasma concentration at a steady state to that seen with transdermal buprenorphine at 35mcg/h(the Transtec 35mcg/h patch)

Simulating Matrix Crack and Delamination Interaction in a Clamped Tapered Beam

Blind predictions were conducted to validate a discrete crack methodology based on the Floating Node Method to simulate matrix-crack/delamination interaction. The main novel aspects of the approach are: (1) the implementation of the floating node method via an 'extended interface element' to represent delaminations, matrix-cracks and their interaction, (2) application of directional cohesive elements to infer overall delamination direction, and (3) use of delamination direction and stress state at the delamination front to determine migration onset. Overall, good agreement was obtained between simulations and experiments. However, the validation exercise revealed the strong dependence of the simulation of matrix-crack/delamination interaction on the strength data (in this case transverse interlaminar strength, YT) used within the cohesive zone approach applied in this work. This strength value, YT, is itself dependent on the test geometry from which the strength measurement is taken. Thus, choosing an appropriate strength value becomes an ad-hoc step. As a consequence, further work is needed to adequately characterize and assess the accuracy and adequacy of cohesive zone approaches to model small crack growth and crack onset. Additionally, often when simulating damage progression with cohesive zone elements, the strength is lowered while keeping the fracture toughness constant to enable the use of coarser meshes. Results from the present study suggest that this approach is not recommended for any problem involving crack initiation, small crack growth or multiple crack interaction

One-Loop Factorization of the Nucleon g_2-Structure Function in the Non-Singlet Case

We consider the one-loop factorization of the simplest twist-three process: inclusive deep-inelastic scattering of longitudinally-polarized leptons on a transversely-polarized nucleon target. By studying the Compton amplitudes for certain quark and gluon states at one loop, we find the coefficient functions for the non-singlet twist-three distributions in the factorization formula of g_2(x_B,Q^2). The result marks the first step towards a next-to-leading order (NLO) formalism for this transverse-spin-dependent structure function of the nucleon.Comment: 14 pages, revtex4, four figures included, minor change

On multiplicities in length spectra of arithmetic hyperbolic three-orbifolds

Asymptotic laws for mean multiplicities of lengths of closed geodesics in arithmetic hyperbolic three-orbifolds are derived. The sharpest results are obtained for non-compact orbifolds associated with the Bianchi groups SL(2,o) and some congruence subgroups. Similar results hold for cocompact arithmetic quaternion groups, if a conjecture on the number of gaps in their length spectra is true. The results related to the groups above give asymptotic lower bounds for the mean multiplicities in length spectra of arbitrary arithmetic hyperbolic three-orbifolds. The investigation of these multiplicities is motivated by their sensitive effect on the eigenvalue spectrum of the Laplace-Beltrami operator on a hyperbolic orbifold, which may be interpreted as the Hamiltonian of a three-dimensional quantum system being strongly chaotic in the classical limit.Comment: 29 pages, uuencoded ps. Revised version, to appear in NONLINEARIT