Rail Privatisation: The Practice – An Analysis of Seven Case Studies

After a brief description of the proposals for rail privatisation in Great Britain, this paper contrasts these with the proposals and experience in other countries around the world. The proposals and experience in other countries contain some elements of the British proposals, however, the 'open access' element that features strongly in the British proposals has never been experienced on any significant scale elsewhere. In conclusion, experience elsewhere may shed light on the likely outcome of some aspects of the British proposals, but other aspects such as 'open access' and vertical separation are still unknowns

Rail Privatisation: The Economic Theory

The purpose of this paper is to examine the relevance of economic theory to the rail privatisation proposals contained in the Railways Act 1993. After a review of the latest rail privatisation literature four major themes emerged: (1) Contestability and Barriers to Entry. (2) Franchising. (3) Vertical Integration. (4) Horizontal Integration. Following a short review of the rail privatisation proposals the paper presents each theme in the context of the proposals. In conclusion, we highlight a number of future issues which will require monitoring and research in the future. In particular, we identify a number of hypotheses, put forward by both those in favour and against the Government's proposals, that should be tested

A simple explanation of the non-appearance of physical gluons and quarks

We show that the non-appearance of gluons and quarks as physical particles is a rigorous and automatic result of the full, i.e. nonperturbative, nonabelian nature of the color interaction in quantum chromodynamics. This makes it in general impossible to describe the color field as a collection of elementary quanta (gluons). Neither can a quark be an elementary quantum of the quark field, as the color field of which it is the source is itself a source, making isolated noninteracting quarks, crucial for a physical particle interpretation, impossible. In geometrical language, the impossibility of quarks and gluons as physical elementary particles arises due to the fact that the color Yang-Mills space does not have a constant trivial curvature. In QCD, the particles ``gluons'' and ``quarks'' are merely artifacts of an approximation method (the perturbative expansion) and are simply absent in the exact theory. This also coincides with the empirical, experimental evidence.Comment: 8 pages, Latex (to appear in Can.J.Phys.

Critical Statistical Charge for Anyonic Superconductivity

We examine a criterion for the anyonic superconductivity at zero temperature in Abelian matter-coupled Chern-Simons gauge field theories in three dimensions. By solving the Dyson-Schwinger equations, we obtain a critical value of the statistical charge for the superconducting phase in a massless fermion-Chern-Simons model.Comment: 11 pages; to appear in Phys Rev

The Volume of some Non-spherical Horizons and the AdS/CFT Correspondence

We calculate the volumes of a large class of Einstein manifolds, namely Sasaki-Einstein manifolds which are the bases of Ricci-flat affine cones described by polynomial embedding relations in C^n. These volumes are important because they allow us to extend and test the AdS/CFT correspondence. We use these volumes to extend the central charge calculation of Gubser (1998) to the generalized conifolds of Gubser, Shatashvili, and Nekrasov (1999). These volumes also allow one to quantize precisely the D-brane flux of the AdS supergravity solution. We end by demonstrating a relationship between the volumes of these Einstein spaces and the number of holomorphic polynomials (which correspond to chiral primary operators in the field theory dual) on the corresponding affine cone.Comment: 25 pp, LaTeX, 1 figure, v2: refs adde

When is a growth-friendly strategy warranted? A matched comparison of growing rods versus primary posterior spinal fusion in juveniles with early-onset scoliosis

Background: In 7 to 11-year-old juveniles with severe early-onset scoliosis (EOS) the optimal surgical option remains uncertain. This study compares growing rods (GRs) followed by definitive posterior spinal fusion (PSF) versus primary PSF in this population. We hypothesized that the thoracic height afforded by GRs would be offset by increased rigidity, more complications, and more operations. Methods: This retrospective comparative study included EOS patients aged 7.0 to 11.9 years at index surgery treated with GR→PSF or primary PSF during 2013 to 2020. Primary outcomes were thoracic height gain (ΔT1-12H), major curve, complications, and total operations. Primary PSFs were matched with replacement 1-to-n to GR→PSFs by age at index, etiology, and major curve. Results: Twenty-eight GR→PSFs met criteria: 19 magnetically controlled GRs and 9 traditional GRs. Three magnetically controlled GRs were definitively explanted without PSF due to complications. The remaining 25 GR→PSFs were matched to 17 primary PSFs with 100% etiology match, mean Δ major curve 1 degree, and mean Δ age at index 0.5 years (PSFs older). Median ΔT1-12H pre-GR to post-PSF was 4.7 cm with median deformity correction of 37%. Median ΔT1-12H among primary PSFs was 1.9 cm with median deformity correction of 62%. GR→PSFs had mean 1.8 complications and 3.4 operations. Primary PSFs had mean 0.5 complications and 1.3 operations. Matched analysis showed adjusted mean differences of 2.3 cm greater ΔT1-12H among GR→PSFs than their matched primary PSFs, with 25% less overall coronal deformity correction, 1.2 additional complications, and 2.2 additional operations per patient. Conclusions: In juveniles aged 7 to 11 with EOS, on average GRs afford 2 cm of thoracic height over primary PSF at the cost of poorer deformity correction and additional complications and operations. Primary PSF affords an average of 2 cm of thoracic height gain; if an additional 2 cm will be impactful then GRs should be considered. However, in most juveniles the height gained may not warrant the iatrogenic stiffness, complications, and additional operations. Surgeons and families should weigh these benefits and harms when choosing a treatment plan. Level of Evidence: Level III - retrospective comparative study

Twist-2 Heavy Flavor Contributions to the Structure Function g2(x,Q2)g_2(x,Q^2)

The twist--2 heavy flavor contributions to the polarized structure function $g_2(x,Q^2)$ are calculated. We show that this part of $g_2(x,Q^2)$ is related to the heavy flavor contribution to $g_1(x,Q^2)$ by the Wandzura--Wilczek relation to all orders in the strong coupling constant. Numerical results are presented.Comment: 17 pages LATEX, 1 style files, 4 figure

Alzheimer’s disease cerebrospinal fluid biomarkers are not influenced by gravity drip or aspiration extraction methodology

Introduction: Cerebrospinal fluid (CSF) biomarkers, although of established utility in the diagnostic evaluation of Alzheimer's disease (AD), are known to be sensitive to variation based on pre-analytical sample processing. We assessed whether gravity droplet collection versus syringe aspiration was another factor influencing CSF biomarker analyte concentrations and reproducibility. Methods: Standardized lumbar puncture using small calibre atraumatic spinal needles and CSF collection using gravity fed collection followed by syringe aspirated extraction was performed in a sample of elderly individuals participating in a large long-term observational research trial. Analyte assay concentrations were compared. Results: For the 44 total paired samples of gravity collection and aspiration, reproducibility was high for biomarker CSF analyte assay concentrations (concordance correlation [95%CI]: beta-amyloid1-42 (Aβ42) 0.83 [0.71 - 0.90]), t-tau 0.99 [0.98 - 0.99], and phosphorylated tau (p-tau) 0.82 [95 % CI 0.71 - 0.89]) and Bonferroni corrected paired sample t-tests showed no significant differences (group means (SD): Aβ42 366.5 (86.8) vs 354.3 (82.6), p = 0.10; t-tau 83.9 (46.6) vs 84.7 (47.4) p = 0.49; p-tau 43.5 (22.8) vs 40.0 (17.7), p = 0.05). The mean duration of collection was 10.9 minutes for gravity collection and <1 minute for aspiration. Conclusions: Our results demonstrate that aspiration of CSF is comparable to gravity droplet collection for AD biomarker analyses but could considerably accelerate throughput and improve the procedural tolerability for assessment of CSF biomarkers

Ecological Invasion, Roughened Fronts, and a Competitor's Extreme Advance: Integrating Stochastic Spatial-Growth Models

Both community ecology and conservation biology seek further understanding of factors governing the advance of an invasive species. We model biological invasion as an individual-based, stochastic process on a two-dimensional landscape. An ecologically superior invader and a resident species compete for space preemptively. Our general model includes the basic contact process and a variant of the Eden model as special cases. We employ the concept of a "roughened" front to quantify effects of discreteness and stochasticity on invasion; we emphasize the probability distribution of the front-runner's relative position. That is, we analyze the location of the most advanced invader as the extreme deviation about the front's mean position. We find that a class of models with different assumptions about neighborhood interactions exhibit universal characteristics. That is, key features of the invasion dynamics span a class of models, independently of locally detailed demographic rules. Our results integrate theories of invasive spatial growth and generate novel hypotheses linking habitat or landscape size (length of the invading front) to invasion velocity, and to the relative position of the most advanced invader.Comment: The original publication is available at www.springerlink.com/content/8528v8563r7u2742