131 research outputs found

    Passenger Rail Statistics Following the Privatisation of British Rail.

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    In common with other major industries, the rail industry requires significant amounts of high quality information for successful operation. Information relating to the demand and supply of rail services is required to ensure that appropriate services are provided at minimum cost. Given the recent explosion of information technology, data on demand and supply is readily accessible and much improved. The benefits to the industry arising from such improvements should be maintained under the new organisational structures brought about by the 1993 Transport Act. It is the aim of this note to outline current sources of information and key statistics and raise the issue of what provisions are being made to ensure that they are maintained in a consistent and compatible format following privatisation

    Real estate stock selection and attribute preferences

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    The majority of studies that explore property portfolio construction and management strategies utilise highly aggregated ex-post data, but stock selection is known to be a significant determinant of portfolio performance. Thus, here we look at stock selection, focusing on the choices faced by investors, necessitating the collection and analysis of primary data, carried out utilising conjoint analysis. This represents a new step in property research, with the data collection undertaken using a simulation exercise. This enables fund managers to make hypothetical purchase decisions, viewing properties comprising a realistic bundle of attributes and making complex contemporaneous trade-offs between attributes, subject to their stated market and economic forecasts and sector specialism. In total 51 fund managers were surveyed, producing 918 purchase decisions for analysis, with additional data collected regarding fund and personal characteristics. The results reveal that ‘fixed’ property characteristics (location and obsolescence) are dominant in the decision-making process, over and above ‘manageable’ tenant and lease characteristics which can be explicitly included within models of probabilities of income variation. This reveals investors are making ex-ante risk judgements and are considering post acquisition risk management strategies. The study also reveals that behavioural factors affect acquisition decisions

    Proteomic analysis of age-related changes in ovine cerebrospinal fluid

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    Cerebrospinal fluid (CSF) circulates through the brain and has a unique composition reflecting the biological processes of the brain. Identifying ageing CSF biomarkers can aid in understanding the ageing process and interpreting CSF protein changes in neurodegenerative diseases. In this study, ovine CSF proteins from young (1-2 year old), middle aged (3-6 year old) and old (7-10 year old) sheep were systemically studied. CSF proteins were labelled with iTRAQ tagging reagents and fractionated by 2-dimensional high performance, liquid chromatography. Tryptic peptides were identified using MS/MS fragmentation ions for sequencing and quantified from iTRAQ reporter ion intensities at m/z 114, 115, 116 and 117. Two hundred thirty one peptides were detected, from which 143 proteins were identified. There were 52 proteins with >25% increase in concentrations in the old sheep compared to the young. 33 of them increased >25% but 50% but 1 fold [i.e. haptoglobin (Hp), haemoglobin, neuroendocrine protein 7B2, IgM, fibrous sheath interacting protein 1, vimentin]. There were 18 proteins with >25% decrease in concentrations in the old sheep compared to the young. 17 of them decreased >25% but <50%, and histone deacetylase 7 (HDAC7) was gradually decreased for over 80%. Glutathione S-transferase was decreased in middle aged CSF compared to both young and old CSF. The differential expressions of 3 proteins (Hp, neuroendocrine protein 7B2, IgM) were confirmed by immunoassays. These data expand our current knowledge regarding ovine CSF proteins, supply the necessary information to understand the ageing process in the brain and provide a basis for diagnosis of neurodegenerative diseases

    Specific Heat of Liquid Helium in Zero Gravity very near the Lambda Point

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    We report the details and revised analysis of an experiment to measure the specific heat of helium with subnanokelvin temperature resolution near the lambda point. The measurements were made at the vapor pressure spanning the region from 22 mK below the superfluid transition to 4 uK above. The experiment was performed in earth orbit to reduce the rounding of the transition caused by gravitationally induced pressure gradients on earth. Specific heat measurements were made deep in the asymptotic region to within 2 nK of the transition. No evidence of rounding was found to this resolution. The optimum value of the critical exponent describing the specific heat singularity was found to be a = -0.0127+ - 0.0003. This is bracketed by two recent estimates based on renormalization group techniques, but is slightly outside the range of the error of the most recent result. The ratio of the coefficients of the leading order singularity on the two sides of the transition is A+/A- =1.053+ - 0.002, which agrees well with a recent estimate. By combining the specific heat and superfluid density exponents a test of the Josephson scaling relation can be made. Excellent agreement is found based on high precision measurements of the superfluid density made elsewhere. These results represent the most precise tests of theoretical predictions for critical phenomena to date.Comment: 27 Pages, 20 Figure

    Sustainable Harvesting of Tropical Rainforests: Reply to Keto, Scott and Olsen

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    This paper refutes the Keto et al. proposition that the Queensland selection logging system is neither ecologically nor economically sustainable. The key requirements of this system are: (1) that logging guidelines are sympathetic to the silvicultural characteristics of the forest, ensuring adequate regeneration of commercial species and discouraging invasion by weeds; (2) tree-marking by trained staff specifies trees to be retained, trees to be removed and the direction of felling to ensure minimal damage to the residual stand; (3) logging equipment is appropriate and driven by trained operators to ensure minimal damage and soil disturbance, compaction and erosion; (4) prescriptions ensure that adequate stream buffers and steep slopes are excluded from logging; (5) sufficient areas for scientific reference, feature protection and recreation are identified and excluded from logging; and (6) that deficiencies in an evolving system are recognized and remedied, leading to an improved system. Many studies of the effects of logging in these forests have been published and collectively provide a unique demonstration of one possible approach to sustainable timber harvesting

    Magnetic Field Generation in Stars

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    Enormous progress has been made on observing stellar magnetism in stars from the main sequence through to compact objects. Recent data have thrown into sharper relief the vexed question of the origin of stellar magnetic fields, which remains one of the main unanswered questions in astrophysics. In this chapter we review recent work in this area of research. In particular, we look at the fossil field hypothesis which links magnetism in compact stars to magnetism in main sequence and pre-main sequence stars and we consider why its feasibility has now been questioned particularly in the context of highly magnetic white dwarfs. We also review the fossil versus dynamo debate in the context of neutron stars and the roles played by key physical processes such as buoyancy, helicity, and superfluid turbulence,in the generation and stability of neutron star fields. Independent information on the internal magnetic field of neutron stars will come from future gravitational wave detections. Thus we maybe at the dawn of a new era of exciting discoveries in compact star magnetism driven by the opening of a new, non-electromagnetic observational window. We also review recent advances in the theory and computation of magnetohydrodynamic turbulence as it applies to stellar magnetism and dynamo theory. These advances offer insight into the action of stellar dynamos as well as processes whichcontrol the diffusive magnetic flux transport in stars.Comment: 41 pages, 7 figures. Invited review chapter on on magnetic field generation in stars to appear in Space Science Reviews, Springe

    Horizontal Branch Stars: The Interplay between Observations and Theory, and Insights into the Formation of the Galaxy

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    We review HB stars in a broad astrophysical context, including both variable and non-variable stars. A reassessment of the Oosterhoff dichotomy is presented, which provides unprecedented detail regarding its origin and systematics. We show that the Oosterhoff dichotomy and the distribution of globular clusters (GCs) in the HB morphology-metallicity plane both exclude, with high statistical significance, the possibility that the Galactic halo may have formed from the accretion of dwarf galaxies resembling present-day Milky Way satellites such as Fornax, Sagittarius, and the LMC. A rediscussion of the second-parameter problem is presented. A technique is proposed to estimate the HB types of extragalactic GCs on the basis of integrated far-UV photometry. The relationship between the absolute V magnitude of the HB at the RR Lyrae level and metallicity, as obtained on the basis of trigonometric parallax measurements for the star RR Lyrae, is also revisited, giving a distance modulus to the LMC of (m-M)_0 = 18.44+/-0.11. RR Lyrae period change rates are studied. Finally, the conductive opacities used in evolutionary calculations of low-mass stars are investigated. [ABRIDGED]Comment: 56 pages, 22 figures. Invited review, to appear in Astrophysics and Space Scienc

    Light Front Quantization--A Technique for Relativistic and Realistic Nuclear Physics

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    Applications of relativistic light front dynamics to computing wave functions of heavy nuclei are reviewed. The motivation for this is the desire to find wave functions, expressed in terms of the plus-momentum variable, that simplify the analyses of high energy experiments such as deep inelastic scattering, Drell-Yan production, (e,e') and (p,p').Some examples of ordinary quantum mechanics are solved to show that the formalism is tractable. Light-front quantization is reviewed briefly and applied to: infinite nuclear matter within the mean field approximation; a simple static source theory; finite nuclei using the mean field approximation; low-energy pion-nucleon scattering using a chiral Lagrangian; nucleon-nucleon scattering, within the one boson exchange approximation; and, infinite nuclear matter including the effects of two-nucleon correlations. Standard good results for nuclear saturation properties are obtained, with a possible improvement in the computed nuclear compressibility. Manifest rotational invariance is not used as an aid in doing calculations, but it does emerge in the results. It seems that nuclear physics can be done in a manner in which modern nuclear dynamics is respected, boost invariance in the zz-direction is preserved, and in which rotational invariance is maintained. A salient feature is that ω,σ\omega,\sigma and π\pi mesons are important constituents of nuclei. It seems possible to find Lagrangians that yield reasonable descriptions of nuclear deep inelastic scattering and Drell-Yan reactions. Furthermore, the presence of the σ\sigma and ω\omega mesons could provide a nuclear enhancement of the ratio of the cross sections for longitudinally and transversely polarized virtual photons in accord with recent measurements by the HERMES collaboration.Comment: Prepared for Prog. Nucl. Part. Phys. 45 (2000
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