15,185 research outputs found
On the Economics of Integrated Ticketing
In this paper we explore alternative pricing and regulatory strategies within a simple transport network with Cournot duopoly and differentiated demands. We show that whilst firms always prefer to offer integrated ticketing, a social planner will not. With integrated ticketing, the firms always prefer complete collusion but there is not a uniform ranking of some of the less collusive regimes. Society generally prefers the less collusive regimes to complete collusion but prefers some collusion to independent pricing
Genome-Wide Association Study and Gene Expression Analysis Identifies CD84 as a Predictor of Response to Etanercept Therapy in Rheumatoid Arthritis
Anti-tumor necrosis factor alpha (anti-TNF) biologic therapy is a widely used treatment for rheumatoid arthritis (RA). It is unknown why some RA patients fail to respond adequately to anti-TNF therapy, which limits the development of clinical biomarkers to predict response or new drugs to target refractory cases. To understand the biological basis of response to anti-TNF therapy, we conducted a genome-wide association study (GWAS) meta-analysis of more than 2 million common variants in 2,706 RA patients from 13 different collections. Patients were treated with one of three anti-TNF medications: etanercept (n = 733), infliximab (n = 894), or adalimumab (n = 1,071). We identified a SNP (rs6427528) at the 1q23 locus that was associated with change in disease activity score (ΔDAS) in the etanercept subset of patients (P = 8×10-8), but not in the infliximab or adalimumab subsets (P>0.05). The SNP is predicted to disrupt transcription factor binding site motifs in the 3′ UTR of an immune-related gene, CD84, and the allele associated with better response to etanercept was associated with higher CD84 gene expression in peripheral blood mononuclear cells (P = 1×10-11 in 228 non-RA patients and P = 0.004 in 132 RA patients). Consistent with the genetic findings, higher CD84 gene expression correlated with lower cross-sectional DAS (P = 0.02, n = 210) and showed a non-significant trend for better ΔDAS in a subset of RA patients with gene expression data (n = 31, etanercept-treated). A small, multi-ethnic replication showed a non-significant trend towards an association among etanercept-treated RA patients of Portuguese ancestry (n = 139, P = 0.4), but no association among patients of Japanese ancestry (n = 151, P = 0.8). Our study demonstrates that an allele associated with response to etanercept therapy is also associated with CD84 gene expression, and further that CD84 expression correlates with disease activity. These findings support a model in which CD84 genotypes and/or expression may serve as a useful biomarker for response to etanercept treatment in RA patients of European ancestry. © 2013 Cui et al
Measuring the Mass of the Lightest Chargino at the CERN LHC
Results are presented of a feasibility study of techniques for measuring the
mass of the lightest chargino at the CERN LHC. These results suggest that for
one particular mSUGRA model a statistically significant chargino signal can be
identified and the chargino mass reconstructed with a precision of order 11%
for of order 100 fb-1 of data.Comment: 6 pages, 5 figures. To appear in the proceedings of the workshop: Les
Houches 2003: Physics at TeV Scale Collider
Gravitational Self-Force Correction to the Innermost Stable Circular Equatorial Orbit of a Kerr Black Hole
For a self-gravitating particle of mass \mu in orbit around a Kerr black hole
of mass M >> \mu, we compute the O(\mu/M) shift in the frequency of the
innermost stable circular equatorial orbit (ISCEO) due to the conservative
piece of the gravitational self-force acting on the particle. Our treatment is
based on a Hamiltonian formulation of the dynamics in terms of geodesic motion
in a certain locally-defined effective smooth spacetime. We recover the same
result using the so-called first law of binary black-hole mechanics. We give
numerical results for the ISCEO frequency shift as a function of the black
hole's spin amplitude, and compare with predictions based on the post-Newtonian
approximation and the effective one-body model. Our results provide an accurate
strong-field benchmark for spin effects in the general relativistic two-body
problem.Comment: 5 pages, 1 table, 1 figure, matches version published in PRL. Raw
data of H_int/mu are available at
http://link.aps.org/supplemental/10.1103/PhysRevLett.113.16110
Network Regulation Using an Agent
This paper introduces a new regulatory concept: the independent profit-maximising regulatory agent, as a possible model for regulating network industries where complex demand interdependencies, in particular demand complementarities, make traditional methods of regulation difficult. We derive a simple theoretical network model with differentiated demands and explore alternative competitive and regulatory strategies. We show that the employment of an independent profit-maximising agent may offer a partial solution to the problem of network regulation, yielding outcomes which involve all parties pursuing their own interests yet are relatively desirable to both firms and society
Environmental Management Accounting - Estimating the Benefit Side
The presentation focuses on estimating benefits of environmental projects and achievements like image improvement, gaining an environmental award, profit from environmentally benign products, risk reduction benefits, etc. The paper integrates the results and experience gained in three different fields: EMA, evaluation of natural resources and working as a consultan
Overview of Solid Target Studies for a Neutrino Factory
The UK programme of high power target developments for a Neutrino Factory is centred on the study of high-Z materials (tungsten, tantalum). A description of lifetime shock tests on candidate materials is given as part of the research into a solid target solution. A fast high current pulse is applied to a thin wire of the sample material and the lifetime measured from the number of pulses before failure. These measurements are made at temperatures up to ~2000 K. The stress on the wire is calculated using the LS-DYNA code and compared to the stress expected in the real Neutrino Factory target. It has been found that tantalum is too weak to sustain prolonged stress at these temperatures but a tungsten wire has reached over 26 million pulses (equivalent to more than ten years of operation at the Neutrino Factory). An account is given of the optimisation of secondary pion production from the target and the issues related to mounting the target in the muon capture solenoid and target station are discussed
Epitaxial designs for maximizing efficiency in resonant tunnelling diode based terahertz emitters
We discuss the modelling of high current density InGaAs/AlAs/InP resonant tunneling diodes to maximize their efficiency as THz emitters. A figure of merit which contributes to the wall plug efficiency, the intrinsic resonator efficiency, is used for the development of epitaxial designs. With the contribution of key parameters identified, we analyze the limitations of accumulated stress to assess the manufacturability of such designs. Optimal epitaxial designs are revealed, utilizing thin barriers, with a wide and shallow quantum well that satisfies the strained layer epitaxy constraint. We then assess the advantages to epitaxial perfection and electrical characteristics provided by devices with a narrow InAs sub-well inside a lattice-matched InGaAs alloy. These new structures will assist in the realization of the next-generation submillimeter emitters
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