Stable configurations of hybrid stars with colour-flavour-locked core

We construct static and mass-shedding limit sequences of hybrid stars, composed of colour flavour locked (CFL) quark matter core, for a set of equations of state (EOSs). The EOS for the hadronic matter is obtained using appropriately calibrated extended field theoretical based relativistic mean-field model. The MIT bag model is employed to compute the EOSs of the CFL quark matter for different values of the CFL gap parameter in the range of $50 - 150\text{MeV}$ with the deconfinement phase transition density ranging from $4\rho_0 - 6\rho_0$ ($\rho_0 = 0.16\text{fm}^{-3}$). We find, depending on the values of the CFL gap parameter and the deconfinement phase transition density, the sequences of stable configurations of hybrid stars either form third families of the compact stars or bifurcate from the hadronic sequence. The hybrid stars have masses $1.0 - 2.1 M_\odot$ with radii $9 - 13.5$ km. The maximum values of mass shedding limit frequency for such hybrid stars are $1 -2$ kHz. For the smaller values of the CFL gap parameter and the deconfinement phase transition density, mass-radius relationships are in harmony with those deduced by applying improved hydrogen atmosphere model to fit the high quality spectra from compact star X7 in the globular cluster 47 Tucanae. We observed for some cases that the third family of compact stars exist in the static sequence, but, disappear from the mass-shedding limit sequence. Our investigation suggests that the third family of compact stars in the mass-shedding limit sequence is more likely to appear, provided they have maximum mass in the static limit higher than their second family counterpart composed of pure hadronic matter.Comment: 27 pages including 10 figures. Accepted in Phys. Rev.

Applicability of Temporal Data Models to Query Multilevel Security Databases: A Case Study

In a multilevel security database there are multiple beliefs about a given real world object. The ability of a database model to accommodate multiple beliefs is termed polyinstantiation in the multilevel security literature. In this paper we remark that in an abstract sense polyinstantiation is a priori present in all models for temporal and spatial databases. In particular we investigate the applicability of the parametric model for temporal data to query multilevel security data and, as a case study, compare it to a model for multilevel security given by Winslett, Smith, and Qian

A Bibliography and Index of Our Works on Belief Data: Concept of Error and Multilevel Security

In 1988 we initiated our work on belief data. The work proceeded in two phases: in the first phase we formalized the concept of error in everyday record keeping, and in the second phase we considered multilevel security. The purpose of this report is to create an awareness about our works on belief data and to serve as a guide for the following manuscripts. The first two manuscripts are on the concept of errors, and the latter three are on multilevel security. Except [TR97-17], all manuscripts are in their original form

OhBench: The Ozsoyoglu-Hou workbench for database experimentation

OhBench is a workbench for database system development. We have named it after Gultekin Ozsoyoglu and Wen-chi Hou, who designed and implemented it at Case Western Reserve University. The original name of the workbench was ERAM. The target of the workbench is to deliver OhBase, a general purpose database system, which can be used by a user community to program database applications in an SQL-like multiuser environment. The design of the workbench is open ended, leaving ample of possibilities for changes and extensions. OhBench includes the source code and it is suitable for interesting programming projects in a realistic time frame. In this document we give a brief account of OhBench and OhBase

Non-rotating and rotating neutron stars in the extended field theoretical model

We study the properties of non-rotating and rotating neutron stars for a new set of equations of state (EOSs) with different high density behaviour obtained using the extended field theoretical model. The high density behaviour for these EOSs are varied by varying the $\omega-$meson self-coupling and hyperon-meson couplings in such a way that the quality of fit to the bulk nuclear observables, nuclear matter incompressibility coefficient and hyperon-nucleon potential depths remain practically unaffected. We find that the largest value for maximum mass for the non-rotating neutron star is $2.1M_\odot$. The radius for the neutron star with canonical mass is $12.8 - 14.1$ km provided only those EOSs are considered for which maximum mass is larger than $1.6M_\odot$ as it is the lower bound on the maximum mass measured so far. Our results for the very recently discovered fastest rotating neutron star indicate that this star is supra massive with mass $1.7 - 2.7M_\odot$ and circumferential equatorial radius $12 - 19$ km.Comment: 28 pages, 12 figures. Phys. Rev. C (in press