Constraints on the High-Density Nuclear Equation of State from Neutron Star Observables

Depending on the density reached in the cores of neutron stars, such objects may contain stable phases of novel matter found nowhere else in the Universe. This article gives a brief overview of these phases of matter and discusses astrophysical constraints on the high-density equation of state associated with ultra-dense nuclear matter.Comment: 16 pages, 11 figures, Contribution to Proceedings of the 3rd International Workshop on Astronomy and Relativistic Astrophysics (IWARA), 3-6 October 2007, Joao Pessoa, Brazi

Compact Stars, Heavy Ion Collisions, and Possible Lessons For QCD at Finite Densities

Large neutron star masses as the recently measured $1.97\pm0.04$ M$_\odot$ for PSR J1614-2230 provide a valuable lower limit on the stiffness of the equation of state of dense, nuclear and quark matter. Complementary, the analysis of the elliptic flow in heavy ion collisions suggests an upper limit on the EoS stiffness. We illustrate how this dichotomy permits to constrain parameters of effective EoS models which otherwise could not be derived unambiguously from first principles.Comment: 16 pages, 7 figures, 1 table Proceedings contribution for 'HIC for FAIR Workshop and XXVIII Max Born Symposium Satellite meeting for QM 2011' in Wroc{\l}aw, Polan

1-2-3-flavor color superconductivity in compact stars

We suggest a scenario where the three light quark flavors are sequentially deconfined under increasing pressure in cold asymmetric nuclear matter, e.g., as in neutron stars. The basis for our analysis is a chiral quark matter model of Nambu--Jona-Lasinio (NJL) type with diquark pairing in the spin-1 single flavor (CSL) and spin-0 two/three flavor (2SC/CFL) channels, and a Dirac-Brueckner Hartree-Fock (DBHF) approach in the nuclear matter sector. We find that nucleon dissociation sets in at about the saturation density, n_0, when the down-quark Fermi sea is populated (d-quark dripline) due to the flavor asymmetry imposed by beta-equilibrium and charge neutrality. At about 3n_0 u-quarks appear forming a two-flavor color superconducting (2SC) phase, while the s-quark Fermi sea is populated only at still higher baryon density. The hybrid star sequence has a maximum mass of 2.1 M_sun. Two- and three-flavor quark matter phases are found only in gravitationally unstable hybrid star solutions.Comment: 4 pages, 2 figures, to appear in the proceedings of Quark Matter 2008: 20th International Conference on Ultra-Relativistic Nucleus Nucleus Collisions (QM 2008), Jaipur, India, 4-10 Feb 200

From Space to Place and Back Again:Towards an Interface Between Space and Place

Geographic information systems represent and process space whereas people refer to and use place. A question that arises is what are the benefits of introducing a unified data model that combines the rigid representation of space and the information-rich concepts of place. In this work we contribute to this research question by proposing a two-way interface that aims to bridge the notions of space and place. This interface relies on the four conceptions of space and interconnected spatial objects. Step-by-step descriptions as well as examples are provided to illustrate the intended use of the proposed interface

From Space to Place and Back Again:Towards an Interface Between Space and Place

Geographic information systems represent and process space whereas people refer to and use place. A question that arises is what are the benefits of introducing a unified data model that combines the rigid representation of space and the information-rich concepts of place. In this work we contribute to this research question by proposing a two-way interface that aims to bridge the notions of space and place. This interface relies on the four conceptions of space and interconnected spatial objects. Step-by-step descriptions as well as examples are provided to illustrate the intended use of the proposed interface

Novel features of J/ΨJ/\Psi dissociation in matter

We make a detailed study of the effect that the recently predicted modification of the in-medium masses of charmed mesons would have on $J/\Psi$ dissociation on pion and $\rho$-meson comovers in relativistic heavy ion collisions. We find a substantial dependence of the $J/\Psi$ absorption rates on the density and temperature of the nuclear matter. This suggests that a quantitative analysis of $J/\Psi$ dissociation in nucleus nucleus collisions should include the effects of the modification of meson masses in dense matter.Comment: 7 pages, espcrc2, including 5 ps-figures, to be pub. in Phys. Lett.

Myths and realities about the recovery of L׳Aquila after the earthquake

AbstractThere is a set of myths which are linked to the recovery of L׳Aquila, such as: the L׳Aquila recovery has come to a halt, it is still in an early recovery phase, and there is economic stagnation. The objective of this paper is threefold: (a) to identify and develop a set of spatial indicators for the case of L׳Aquila, (b) to test the feasibility of a numerical assessment of these spatial indicators as a method to monitor the progress of a recovery process after an earthquake and (c) to answer the question whether the recovery process in L׳Aquila stagnates or not. We hypothesize that after an earthquake the spatial distribution of expert defined variables can constitute an index to assess the recovery process more objectively. In these articles, we aggregated several indicators of building conditions to characterize the physical dimension, and we developed building use indicators to serve as proxies for the socio-economic dimension while aiming for transferability of this approach. The methodology of this research entailed six steps: (1) fieldwork, (2) selection of a sampling area, (3) selection of the variables and indicators for the physical and socio-economic dimensions, (4) analyses of the recovery progress using spatial indicators by comparing the changes in the restricted core area as well as building use over time; (5) selection and integration of the results through expert weighting; and (6) determining hotspots of recovery in L׳Aquila. Eight categories of building conditions and twelve categories of building use were identified. Both indicators: building condition and building use are aggregated into a recovery index. The reconstruction process in the city center of L׳Aquila seems to stagnate, which is reflected by the five following variables: percentage of buildings with on-going reconstruction, partial reconstruction, reconstruction projected residential building use and transport facilities. These five factors were still at low levels within the core area in 2012. Nevertheless, we can conclude that the recovery process in L׳Aquila did not come to a halt but is still ongoing, albeit being slow

QADI as a New Method and Alternative to Kappa for Accuracy Assessment of Remote Sensing-Based Image Classification

Classification is a very common image processing task. The accuracy of the classified map is typically assessed through a comparison with real-world situations or with available reference data to estimate the reliability of the classification results. Common accuracy assessment approaches are based on an error matrix and provide a measure for the overall accuracy. A frequently used index is the Kappa index. As the Kappa index has increasingly been criticized, various alternative measures have been investigated with minimal success in practice. In this article, we introduce a novel index that overcomes the limitations. Unlike Kappa, it is not sensitive to asymmetric distributions. The quantity and allocation disagreement index (QADI) index computes the degree of disagreement between the classification results and reference maps by counting wrongly labeled pixels as A and quantifying the difference in the pixel count for each class between the classified map and reference data as Q. These values are then used to determine a quantitative QADI index value, which indicates the value of disagreement and difference between a classification result and training data. It can also be used to generate a graph that indicates the degree to which each factor contributes to the disagreement. The efficiency of Kappa and QADI were compared in six use cases. The results indicate that the QADI index generates more reliable classification accuracy assessments than the traditional Kappa can do. We also developed a toolbox in a GIS software environment.University of Tabriz, International and Academic Cooperation DirectionAlexander Von Humboldt FoundationPeer Reviewe