What science can teach us about “Enhanced Interrogation”

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The International Dimension of the Antitrust Practice in Poland, Hungary and the Czech Republic

This paper analyses how the competition authorities in the Czech republic, Poland and Hungary (CPH) have dealt with the interface between trade and competition in their actual practice. The following findings emerge (i) there has not been any significant conflict in the allocation of jurisdiction between CPH on the one hand and the EU on the other hand. This may however be due to a lack of integration between these countries. (ii) the definition of the relevant geographic market suffers from significant shortcomings in each country under review with a general bias in favour of narrow market definition. Problems are most severe in the Czech republic. (iii) Anti-trust agencies in all three countries have attempted to advocate competition in the formulation of trade policy. Developments regarding the independence of the agencies is however mixed. There are some worrying signs that the Polish agency has become less independent whereas the Hungarian agency has probably become even more independent (iv) anti-trust agencies in all three countries could indeed be pursuing objectives of industrial policy in the exercise of merger control towards foreign firms. The situation is most severe in Poland where the suspicion arises that profitable market positions have been auctioned off to foreign buyers in exchange for commitments which are unrelated to the competitive situation.antitrust; transition

Investigating Multiple Solutions in the Constrained Minimal Supersymmetric Standard Model

Recent work has shown that the Constrained Minimal Supersymmetric Standard Model (CMSSM) can possess several distinct solutions for certain values of its parameters. The extra solutions were not previously found by public supersymmetric spectrum generators because fixed point iteration (the algorithm used by the generators) is unstable in the neighbourhood of these solutions. The existence of the additional solutions calls into question the robustness of exclusion limits derived from collider experiments and cosmological observations upon the CMSSM, because limits were only placed on one of the solutions. Here, we map the CMSSM by exploring its multi-dimensional parameter space using the shooting method, which is not subject to the stability issues which can plague fixed point iteration. We are able to find multiple solutions where in all previous literature only one was found. The multiple solutions are of two distinct classes. One class, close to the border of bad electroweak symmetry breaking, is disfavoured by LEP2 searches for neutralinos and charginos. The other class has sparticles that are heavy enough to evade the LEP2 bounds. Chargino masses may differ by up to around 10% between the different solutions, whereas other sparticle masses differ at the sub-percent level. The prediction for the dark matter relic density can vary by a hundred percent or more between the different solutions, so analyses employing the dark matter constraint are incomplete without their inclusion.Comment: 30 pages, 12 figures, 2 tables; v2: added discussion on speed of shooting method, fixed typos, matches published versio

The Modernisation of EU Competition Policy : Making the Network Operate

This paper does not seek to evaluate whether decentralisation of the implementation of Art.81 ECT is desirable but simply analyses how the network of enforcers envisaged in the White Paper would operate. We identify two issues. We observe that in the proposed framework, simultaneous enforcement by several authorities is likely to occur and that each member states will have little incentive to take into account in its decision the interests of other member states. We show that such system of enforcement can have a "disintegrating effect", to the extent that it does not allow for a balancing between positive and negative net benefits across member states. We suggest that in order to avoid these effects, some co-ordination between the members of the network should be organised. In particular, we advocate the re-emergence in the intra-EC context of a 'positive comity' obligation and we suggest that a formal procedure for co-ordination between different institutions should be laid down (as in the US). We further observe that the accountability of antitrust authorities could deteriorate in the White Paper era. In order to address this concern, we suggest that institutional constraints like accountability and independence standards should be imposed on member states. Finally, drawing on the US experience with multiple enforcement, we argue that the role of the Commission should be as much to manage regulatory innovation (arising from the enforcement activity of member states) as to resolve conflict.antitrust; institution design

Brane Gases on K3 and Calabi-Yau Manifolds

We initiate the study of Brane Gas Cosmology (BGC) on manifolds with non-trivial holonomy. Such compactifications are required within the context of superstring theory in order to make connections with realistic particle physics. We study the dynamics of brane gases constructed from various string theories on background spaces having a K3 submanifold. The K3 compactifications provide a stepping stone for generalising the model to the case of a full Calabi-Yau three-fold. Duality symmetries are discussed within a cosmological context. Using a duality, we arrive at an N=2 theory in four-dimensions compactified on a Calabi-Yau manifold with SU(3) holonomy. We argue that the Brane Gas model compactified on such spaces maintains the successes of the trivial toroidal compactification while greatly enhancing its connection to particle physics. The initial state of the universe is taken to be a small, hot and dense gas of p-branes near thermal equilibrium. The universe has no initial singularity and the dynamics of string winding modes allow three spatial dimensions to grow large, providing a possible solution to the dimensionality problem of string theory.Comment: 26 pages; Significant revisions: review material truncated; presentation improve

Generalization of the noise model for time-distance helioseismology

In time-distance helioseismology, information about the solar interior is encoded in measurements of travel times between pairs of points on the solar surface. Travel times are deduced from the cross-covariance of the random wave field. Here we consider travel times and also products of travel times as observables. They contain information about e.g. the statistical properties of convection in the Sun. The basic assumption of the model is that noise is the result of the stochastic excitation of solar waves, a random process which is stationary and Gaussian. We generalize the existing noise model (Gizon and Birch 2004) by dropping the assumption of horizontal spatial homogeneity. Using a recurrence relation, we calculate the noise covariance matrices for the moments of order 4, 6, and 8 of the observed wave field, for the moments of order 2, 3 and 4 of the cross-covariance, and for the moments of order 2, 3 and 4 of the travel times. All noise covariance matrices depend only on the expectation value of the cross-covariance of the observed wave field. For products of travel times, the noise covariance matrix consists of three terms proportional to $1/T$, $1/T^2$, and $1/T^3$, where $T$ is the duration of the observations. For typical observation times of a few hours, the term proportional to $1/T^2$ dominates and $Cov[\tau_1 \tau_2, \tau_3 \tau_4] \approx Cov[\tau_1, \tau_3] Cov[\tau_2, \tau_4] + Cov[\tau_1, \tau_4] Cov[\tau_2, \tau_3]$, where the $\tau_i$ are arbitrary travel times. This result is confirmed for $p_1$ travel times by Monte Carlo simulations and comparisons with SDO/HMI observations. General and accurate formulae have been derived to model the noise covariance matrix of helioseismic travel times and products of travel times. These results could easily be generalized to other methods of local helioseismology, such as helioseismic holography and ring diagram analysis

Signal and noise in helioseismic holography

Helioseismic holography is an imaging technique used to study heterogeneities and flows in the solar interior from observations of solar oscillations at the surface. Holograms contain noise due to the stochastic nature of solar oscillations. We provide a theoretical framework for modeling signal and noise in Porter-Bojarski helioseismic holography. The wave equation may be recast into a Helmholtz-like equation, so as to connect with the acoustics literature and define the holography Green's function in a meaningful way. Sources of wave excitation are assumed to be stationary, horizontally homogeneous, and spatially uncorrelated. Using the first Born approximation we calculate holograms in the presence of perturbations in sound-speed, density, flows, and source covariance, as well as the noise level as a function of position. This work is a direct extension of the methods used in time-distance helioseismology to model signal and noise. To illustrate the theory, we compute the hologram intensity numerically for a buried sound-speed perturbation at different depths in the solar interior. The reference Green's function is obtained for a spherically-symmetric solar model using a finite-element solver in the frequency domain. Below the pupil area on the surface, we find that the spatial resolution of the hologram intensity is very close to half the local wavelength. For a sound-speed perturbation of size comparable to the local spatial resolution, the signal-to-noise ratio is approximately constant with depth. Averaging the hologram intensity over a number $N$ of frequencies above 3 mHz increases the signal-to-noise ratio by a factor nearly equal to the square root of $N$. This may not be the case at lower frequencies, where large variations in the holographic signal are due to the individual contributions of the long-lived modes of oscillation.Comment: Submitted to Astronomy and Astrophysic