SEMISTRUCTURED PROBABILISTIC OBJECT QUERY LANGUAGE (A Query Language for Semistructured Probabilistic Data)

This work presents SPOQL, a structured query language for Semistructured Probabilistic Object (SPO) model [4]. The original query language for semistructured probabilistic database management system [20], SP-Algebra [4], has limitations such as complex functional notation and unfamiliarity to application programmers. SPOQL alleviates these problems by providing a user friendly and familiar SQL-like declarative syntax for writing queries against SPDBMS. We show that parsing SPOQL queries is a more involving task than parsing SQL queries. We describe the evaluation algorithm for SPOQL queries that we have implemented

Quantum Gravitational Collapse and Hawking Radiation in 2+1 Dimensions

We develop the canonical theory of gravitational collapse in 2+1 dimensions with a negative cosmological constant and obtain exact solutions of the Wheeler--DeWitt equation regularized on a lattice. We employ these solutions to derive the Hawking radiation from black holes formed in all models of dust collapse. We obtain an (approximate) Planck spectrum near the horizon characterized by the Hawking temperature $T_{\mathrm H}=\hbar\sqrt{G\Lambda M}/2\pi$, where $M$ is the mass of a black hole that is presumed to form at the center of the collapsing matter cloud and $-\Lambda$ is the cosmological constant. Our solutions to the Wheeler-DeWitt equation are exact, so we are able to reliably compute the greybody factors that result from going beyond the near horizon region.Comment: 27 pages, no figure

Study cases of two small medium size enterprises (SMEs) in the southern metropolitan region of Buenos Aires

The main purpose of the paper is to understand which specific strategies Argentinian small medium-sized enterprises (SMEs) adopted during the second half of the 20th century to adapt to and confront economic cycles, and how the learning process allowed them to endure over time. To do so, we focus on the learning paths of two metallurgy firms established in the Quilmes District, south of the Buenos Aires Metropolitan Region: SINPAR (1931), and Gora (1958), which have accumulated experience and recognition at the local level, for more than sixty years. By studying those companies, we aim to a twofold result. The first is to show that the strategies of the SMEs in the manufacturing sector are based on internal capabilities of meeting demand and responding to the domestic economy. The second one associates the long-term endurance of companies with a strong family management structure over more than one generation. Based on those results, we will argue that the SMEs lasted over time because their founders and successors developed the ability to adapt and of learning how to respond to and take advantage of the uncertainty, restrictions and opportunities of the Argentinian economy

Effects of charge on the interior volume of BTZ black holes

In this article we extend the variational technique for maximal volume estimation of a black hole developed by Christodoulou and Rovelli (CR) to the case of a charged BTZ black hole in 2+1 dimensions. The technique involves a study of the equation of motion of a hypothetical particle moving in an auxiliary manifold defined by spacetime variables. We then compare this estimation with the volume computed using maximization method and extrinsic curvature method. The charge Q of the black hole appears as a log term in the metric and hence an analytical solution for the volume does not exist. So first we compute the steady state radius and the volume for limiting case when the charge Q is very small i.e. Q << 1 and then carry out a numerical analysis to solve for the volume for more generic values of the charge. We find that the volume grows monotonically with the advance time. We further investigate the functional behaviour of the entropy of a massless scalar field living on the maximal hypersurface of a near extremal black hole. We show that this volume entropy exhibits a very different functional form compared to the horizon entropy.Comment: 11 pages, 5 figure