100 research outputs found

    The political economy of electricity market liberalization: a cross-country approach

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    More than half of the countries in the world have introduced a reform process in their power sectors and billions of dollars have been spent on liberalizing electricity markets around the world. Ideological considerations, political composition of governments and educational/professional background of leaders have played and will play a crucial role throughout the reform process. Adapting a political economy perspective, this paper attempts to discover the impact of political economy variables on the liberalization process in electricity markets. Empirical models are developed and analysed using panel data from 55 developed and developing countries covering the period 1975–2010. The research findings suggest that there is a significant negative relationship between electricity market liberalization and the size of industry sector, meaning that countries with larger industry sectors tend to liberalize less. Also, we detect a negative correlation between polity score and power sector liberalization, that is; it cannot be argued that liberalization policies are stronger in more democratic countries. On the other hand, our results imply that countries that receive foreign financial aid or assistance are more likely to liberalize their electricity markets. In OECD countries, single-party governments accelerate the reform process by reducing public ownership and vertical integration. Moreover, we detect a negative relationship between the years the chief executive has been in office and the reform progress in OECD countries. Furthermore, we identify a decrease in vertical integration in electricity industry during the terms of parties with “right” or “left” ideologies in OECD countries. Additionally, professional and educational background of head of executive branch (prime minister, president and so on) seem to have very significant impact on reform process in OECD countries, but this is not the case in non-OECD countries. Leaders with a professional background as entrepreneurs speed up electricity market liberalization process in OECD countries while those with a background as economists slow it down. As for educational background, the reforms seem to progress slower in OECD countries if the head of executive has an educational background in economics or natural science. As a final point, the study suggests that EU or OECD membership, the existence of electricity market reform idea, population density, electricity consumption, income level, educational level, imports of goods and services (as % of GDP) and country specific features have a strong correlation with liberalization process in electricity markets

    The Dipole Anisotropy of the 2mass Redshift Survey

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    We estimate the flux weighted acceleration on the Local Group (LG) from the near-infrared Two Micron All Sky Redshift Survey (2MRS). The near-infrared flux weighted dipoles are very robust because they closely approximate a mass weighted dipole, bypassing the effects of redshift distortions and require no preferred reference frame. We use this method with the redshift information to determine the change in dipole with distance. The LG dipole seemingly converges by 60 Mpc/h. Assuming convergence, the comparison of the 2MRS flux dipole and the CMB dipole provides a value for the combination of the mass density and luminosity bias parameters Omega_m^0.6/b_L= 0.40+/-0.09.Comment: 4 pages, 2 figures, Contribution to Rencontres de Moriond: Contents and Structures of the Universe, March 18-25, 2006, La Thuil

    Luminous superclusters: remnants from inflation

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    We derive the luminosity and multiplicity functions of superclusters compiled for the 2dF Galaxy Redshift Survey, the Sloan Digital Sky Survey (Data Release 4), and for three samples of simulated superclusters. We find for all supercluster samples Density Field (DF) clusters, which represent high-density peaks of the class of Abell clusters, and use median luminosities/masses of richness class 1 DF-clusters to calculate relative luminosity/mass functions. We show that the fraction of very luminous (massive) superclusters in real samples is more than tenfolds greater than in simulated samples. Superclusters are generated by large-scale density perturbations which evolve very slowly. The absence of very luminous superclusters in simulations can be explained either by non-proper treatment of large-scale perturbations, or by some yet unknown processes in the very early Universe.Comment: 6 pages, 3 Figures, submitted for Astronomy and Astrophysic

    Superclusters of galaxies from the 2dF redshift survey. I. The catalogue

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    We use the 2dF Galaxy Redshift Survey data to compile catalogues of superclusters for the Northern and Southern regions of the 2dFGRS, altogether 543 superclusters at redshifts 0.009 < z < 0.2. We analyse methods of compiling supercluster catalogues and use results of the Millennium Simulation to investigate possible selection effects and errors. We find that the most effective method is the density field method using smoothing with an Epanechnikov kernel of radius 8 Mpc/h. We derive positions of the highest luminosity density peaks and find the most luminous cluster in the vicinity of the peak, this cluster is considered as the main cluster and its brightest galaxy the main galaxy of the supercluster. In catalogues we give equatorial coordinates and distances of superclusters as determined by positions of their main clusters. We also calculate the expected total luminosities of the superclusters.Comment: 16 pages, 11 figures, submitted for Astronomy and Astrophysics. High-resolution pdf file and supplementary data can be found at http://www.aai.ee/~maret/2dfscl.htm

    Superclusters of galaxies from the 2dF redshift survey. II. Comparison with simulations

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    We investigate properties of superclusters of galaxies found on the basis of the 2dF Galaxy Redshift Survey, and compare them with properties of superclusters from the Millennium Simulation. We study the dependence of various characteristics of superclusters on their distance from the observer, on their total luminosity, and on their multiplicity. The multiplicity is defined by the number of Density Field (DF) clusters in superclusters. Using the multiplicity we divide superclusters into four richness classes: poor, medium, rich and extremely rich. We show that superclusters are asymmetrical and have multi-branching filamentary structure, with the degree of asymmetry and filamentarity being higher for the more luminous and richer superclusters. The comparison of real superclusters with Millennium superclusters shows that most properties of simulated superclusters agree very well with real data, the main differences being in the luminosity and multiplicity distributions.Comment: 15 pages, 13 Figures, submitted for Astronomy and Astrophysic

    The richest superclusters. I. Morphology

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    We study the morphology of the richest superclusters from the catalogues of superclusters of galaxies in the 2dF Galaxy Redshift Survey and compare the morphology of real superclusters with model superclusters in the Millennium Simulation. We use Minkowski functionals and shapefinders to quantify the morphology of superclusters: their sizes, shapes, and clumpiness. We generate empirical models of simple geometry to understand which morphologies correspond to the supercluster shapefinders. We show that rich superclusters have elongated, filamentary shapes with high-density clumps in their core regions. The clumpiness of superclusters is determined using the fourth Minkowski functional V3V_3. In the K1K_1-K2K_2 shapefinder plane the morphology of superclusters is described by a curve which is characteristic to multi-branching filaments. We also find that the differences between the fourth Minkowski functional V3V_3 for the bright and faint galaxies in observed superclusters are larger than in simulated superclusters.Comment: 14 pages, 8 figures, submitted to Astronomy and Astrophysic

    Reconstructed Density and Velocity Fields from the 2MASS Redshift Survey

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    We present the reconstructed real-space density and the predicted velocity fields from the Two Mass Redshift Survey (2MRS). The 2MRS is the densest all-sky redshift survey to date and includes about 23,200 galaxies with extinction corrected magnitudes brighter than K = 11.25. Our method is based on the expansion of these fields in Fourier-Bessel functions. Within this framework, the linear redshift distortions only affect the density field in the radial direction and can easily be deconvolved using a distortion matrix. Moreover, in this coordinate system, the velocity field is related to the density field by a simple linear transformation. The shot noise errors in the reconstructions are suppressed by means of a Wiener filter which yields a minimum variance estimate of the density and velocity fields. Using the reconstructed real-space density fields, we identify all major superclusters and voids. At 50 Mpc/h, our reconstructed velocity field indicates a back-side infall to the Great Attractor region of vi = (491 +/- 200)(beta/0.5) km/sec in the Local Group frame and v = (64 +/- 205)(beta/0.5) km/sec in the cosmic microwave background (CMB) frame and beta is the redshift distortion parameter. The direction of the reconstructed dipole agrees well with the dipole derived by Erdogdu et al. (2006). The misalignment between the reconstructed 2MRS and the CMB dipoles drops to 13 degrees at around 5000 km/sec but then increases at larger distances. A version of this paper with high resolution figures can be obtained from http://www.nottingham.ac.uk/~ppzzpeComment: 21 pages. 22 figures, accepted for publication in MNRAS. The figures are coarsely resolved, a version of this paper with high resolution figures can be obtained from http://www.nottingham.ac.uk/~ppzzp

    Upper limits on neutrino masses from the 2dFGRS and WMAP: the role of priors

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    Solar, atmospheric, and reactor neutrino experiments have confirmed neutrino oscillations, implying that neutrinos have non-zero mass, but without pinning down their absolute masses. While it is established that the effect of neutrinos on the evolution of cosmic structure is small, the upper limits derived from large-scale structure data could help significantly to constrain the absolute scale of the neutrino masses. In a recent paper the 2dF Galaxy Redshift Survey (2dFGRS) team provided an upper limit m_nu,tot < 2.2 eV, i.e. approximately 0.7 eV for each of the three neutrino flavours, or phrased in terms of their contributioin to the matter density, Omega_nu/Omega_m < 0.16. Here we discuss this analysis in greater detail, considering issues of assumed 'priors' like the matter density Omega_m and the bias of the galaxy distribution with respect the dark matter distribution. As the suppression of the power spectrum depends on the ratio Omega_nu/Omega_m, we find that the out-of- fashion Mixed Dark Matter Model, with Omega_nu=0.2, Omega_m=1 and no cosmological constant, fits the 2dFGRS power spectrum and the CMB data reasonably well, but only for a Hubble constant H_0<50 km/s/Mpc. As a consequence, excluding low values of the Hubble constant, e.g. with the HST Key Project is important in order to get a strong constraint on the neutrino masses. We also comment on the improved limit by the WMAP team, and point out that the main neutrino signature comes from the 2dFGRS and the Lyman alpha forest.Comment: 24 pages, 12 figures Minor changes to matched version published in JCA
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