100 research outputs found
The political economy of electricity market liberalization: a cross-country approach
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 1975â2010. 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 ârightâ or âleftâ 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
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
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
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
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
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 . In the - 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 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
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
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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