Measure in the 2D Regge quantum gravity

We propose a version of the 2D Regge calculus, in which the areas of all triangles are equal to each other. In this discretization Lund - Regge measure over link lengths is simplified considerably. Contrary to the usual Regge models with Lund - Regge measure, where this measure is nonlocal and rather complicated, the models based on our approach can be investigated using the numerical simulations in a rather simple way.Comment: Derivation of the basic result is reconsidered. Accepted for publication in Phys. Lett.

Geodesics and the Einstein nonlinear wave system

AbstractThe system under consideration is Einstein's equation Rμν(g)−gμνR(g)/2=8πGTμν for a pseudo-Riemannian metric g coupled to a semi-linear wave equation for a complex function φ. Assume that this wave equation on Minkowski space admits a stable solitary wave of the type known as nontopological solitons. The system is studied in the scaling limit in which the solitons have small size ε and amplitude δ with δ⩽δ0ε7/4. It is proved that, for ε sufficiently small, given a solution of the vacuum Einstein equation, i.e., a Ricci flat pseudo-Riemannian metric γ, there exists a finite time interval, independent of ε,δ, on which there is a solution of the full system (g,φ) with (g−γ) small and φ close to a nontopological soliton centred on a time-like geodesic (in appropriate Sobolev norms)

International Islamic finance

Islamic Banking has both classical and modern connections. Guidelines to acceptable behaviour with regard to money and property were offered in the Quran whilst the compilation of further material and its interpretation is a process that began with the death of the Prophet and continues to the present day. Upon the establishment of the first Islamic bank twenty-five years ago, Islamic finance passed beyond the realm of jurisprudence and has since gained the respect of Western economis1;s and bankers alike. This period has spawned a considerable volume of theoretical works which detail the wide-ranging benefits particular to an interest-free financial system, and yet, little has been addressed to the experience of Islamic banks themselves. One of the problems for Middle Eastern banking in general is that an Arab marketplace, similar to the US or European example, still does not exist. By examining the performance of Islamic banks in Bahrain, the Arab world's closest equivalent, it is possible to assess the degree of success that a move to Western markets has allowed. The introductory chapter investigates the relationship between Islamic economic theory and practice while chapter two considers Islamic banking theory and comments upon the financing methods available in this sphere. The third chapter looks at the Euromarkets in the context of n6a-oriented finance and the opportunities that exist there for Islamic banks. Chapter four views Islamic financial activity in London and Geneva which contrasts with the experience of Islamic offshore in situations in Bahrain, the content of chapter five. A separate chapter studies the role of the Islamic Development Bank in promoting the spread of Islamic finance and considers how successful the bank has been in Islamic terms. The concluding chapter draws on the experience of n6a-free financial institutions over recent years to assess the future status and activities of international Islamic banking

Tax Structures and Economic Growth in Nigeria: Disaggregated Empirical Evidence

This paper seeks to investigate the empiricism behind the New National Tax Policy in Nigeria by employing co-integration and error correction as methods of empirical estimation with an empirical strategy of disaggregation. In line with the objective of the paper, empirical results indicate that while the policy of direct taxation is significantly and positively correlated with economic growth, indirect taxation proved insignificant with its negative impact on economic growth in Nigeria.  The paper indeed ascertained that the tax-based revenue profile in Nigeria is skewed towards direct taxes. By implication, the global transition from direct taxation to indirect taxation lack empirical justification in developing countries such as Nigeria. Thus, we recommend that rather than expand the indirect tax structures, the government should expand the structures of direct taxes in Nigeria.  A major contribution of the paper to knowledge is the fact that on the basis of the hypotheses tested, the empirical paper closes the knowledge gap induced by inconclusive evidence on the growth effects of taxation composition which most often has resulted in situations where empirical findings of researches done in developed economies are generalized to developing countries. Key words: Tax structures, direct taxation, indirect taxation, economic growth, Nigeria

Ten Years in Australia Being the Results of his Experience as a Settler During that Period

https://commons.und.edu/settler-literature/1088/thumbnail.jp

Fermionic Linear Optics Revisited

We provide an alternative view of the efficient classical simulatibility of fermionic linear optics in terms of Slater determinants. We investigate the generic effects of two-mode measurements on the Slater number of fermionic states. We argue that most such measurements are not capable (in conjunction with fermion linear optics) of an efficient exact implementation of universal quantum computation. Our arguments do not apply to the two-mode parity measurement, for which exact quantum computation becomes possible, see quant-ph/0401066.Comment: 16 pages, submitted to the special issue of Foundation of Physics in honor of Asher Peres' 70th birthda

Magneto-optical rotation and cross-phase modulation via coherently driven tripod atoms

We study the interaction of a weak probe field, having two orthogonally polarized components, with an optically dense medium of four-level atoms in a tripod configuration. In the presence of a coherent driving laser, electromagnetically induced transparency is attained in the medium, dramatically enhancing its linear as well as nonlinear dispersion while simultaneously suppressing the probe field absorption. We present the semiclassical and fully quantum analysis of the system. We propose an experimentally feasible setup that can induce large Faraday rotation of the probe field polarization and therefore be used for ultra-sensitive optical magnetometry. We then study the Kerr nonlinear coupling between the two components of the probe, demonstrating a novel regime of symmetric, extremely efficient cross-phase modulation, capable of fully entangling two single-photon pulses. This scheme may thus pave the way to photon-based quantum information applications, such as deterministic all-optical quantum computation, dense coding and teleportation.Comment: Corrected typo

Fracture test of a Gothic ribbed vault

A Gothic ribbed vault has been built at the School of Architecture of Madrid in order to investigate the construction complexities of this kind of vaults. The ribbed vault is described in the manuscript of Alonso de Vandelvira, and its shape was reconstructed making using the drawings this architect from the 16th century. The fracture test was carried on by loading the central keystone of the vault until its collapse took place. The experiment was filmed and by doing so, it was possible to observe the failure mechanism of the vault. At the same time, it was interesting to compare this collapse experience with the results obtained using two different me-thods. First, a stability calculation was carried out through graphic statics, and secondly a calcu-lation was performed using the rigid-block analysis method. The focus of this paper is to show and analyze the results of both studies

Prey specialization and morphological conformation of wolves associated with woodland caribou and moose

Morphological analysis of wolves associated with woodland caribou in late succession boreal coniferous forests north of the commercial cut line and those associated with moose in early succession boreal deciduous forests south of the commercial cut line were studied in Ontario. Socalled “moose-wolves” could readily be distinguished from “caribouwolves” in both genders using a few morphological measurements. Wolves associated with woodland caribou were significantly smaller in most measurements, and increased in size within seven years post-harvest as moose totally replaced caribou in the ecosystem. Whether this change in wolf morphology is related to micro-evolutionary change, the migration of larger “moose-wolves” into the area, or both, remains unclear