Plane waves in quantum gravity: breakdown of the classical spacetime

Starting with the Hamiltonian formulation for spacetimes with two commuting spacelike Killing vectors, we construct a midisuperspace model for linearly polarized plane waves in vacuum gravity. This model has no constraints and its degrees of freedom can be interpreted as an infinite and continuous set of annihilation and creation like variables. We also consider a simplified version of the model, in which the number of modes is restricted to a discrete set. In both cases, the quantization is achieved by introducing a Fock representation. We find regularized operators to represent the metric and discuss whether the coherent states of the quantum theory are peaked around classical spacetimes. It is shown that, although the expectation value of the metric on Killing orbits coincides with a classical solution, its relative fluctuations become significant when one approaches a region where null geodesics are focused. In that region, the spacetimes described by coherent states fail to admit an approximate classical description. This result applies as well to the vacuum of the theory.Comment: 11 pages, no figures, version accepted for publication in Phys. Rev.

Sialadenosis in Patients with Advanced Liver Disease

Sialadenosis (sialosis) has been associated most often with alcoholic liver disease and alcoholic cirrhosis, but a number of nutritional deficiencies, diabetes, and bulimia have also been reported to result in sialadenosis. The aim of this study was to determine the prevalence of sialadenosis in patients with advanced liver disease. Patients in the study group consisted of 300 candidates for liver transplantation. Types of liver disease in subjects with clinical evidence of sialadenosis were compared with diagnoses in cases who had no manifestations of sialadenosis. The data were analyzed for significant association. Sialadenosis was found in 28 of the 300 subjects (9.3%). Among these 28 cases, 11 (39.3%) had alcoholic cirrhosis. The remaining 17 (60.7%) had eight other types of liver disease. There was no significant association between sialadenosis and alcoholic cirrhosis (P = 0.389). These findings suggest that both alcoholic and non-alcoholic cirrhosis may lead to the development of sialadenosis. Advanced liver disease is accompanied by multiple nutritional deficiencies which may be exacerbated by alcohol. Similar metabolic abnormalities may occur in patients with diabetes or bulimia. Malnutrition has been associated with autonomic neuropathy, the pathogenic mechanism that has been proposed for sialadenosis

Turks, Arabs and Jewish Immigration into Palestine: 1882-1914

It is commonly maintained that prior to World War I all was well between Jews and Arabs in Palestine. According to this view, the Jews were too few and the Arabs too inarticulate for discord to have manifested itself. Amongst the Arabs there was, at most, only rudimentary opposition to Jewish settlement in the country, and the general harmony was not broken until the British promised national sovereignty to both the Arabs and the Jews in the course of the Great War. This study seeks to do three things. It attempts to trace the development of the Ottoman Government's position regarding Jewish immigration into Palestine between 1882 and 1914, to describe how this policy was translated into practice by the authorities in Palestine, and to discover how the Arabs reacted to this influx of Jews in the light of Ottoman official policy and practice. This study, which is based mainly on diplomatic and Jewish records, reaches the conclusion that the popular notion of Arab- Jewish harmony in Palestine prior to 1914 has little grounding in fact

The Leading British Press on Three Crises in the Middle East: 1947-1957

Content Analysis is a convenient research technique: it can be applied to widely divergent media of communication, and its uses are manifold.1 The following study derives from a content analysis. The vehicle of communication is the newspaper and our purpose is to describe the appraisals made by the leading British press of three post-World War II crises in the Middle East

Ottoman policy and restrictions on Jewish settlement in Palestine: 1881-1908 - part I

Donated by Klaus Kreise

Ottoman practice as regards Jewish settlement in Palestine: 1881-1908

Donated by Klaus Kreise

Turks, Arabs and Jewish Immigration into Palestine

It is commonly maintained that prior to World War I all was well between Jews and Arabs in Palestine. According to this view, the Jews were too few and the Arabs too inarticulate for discord to have manifested itself. Amongst the Arabs there was, at most, only rudimentary opposition to Jewish settlement in the country, and the general harmony was not broken until the British promised national sovereignty to both the Arabs and the Jews in the course of the Great War. This study seeks to do three things. It attempts to trace the development of the Ottoman Government's position regarding Jewish immigration into Palestine between 1882 and 1914, to describe how this policy was translated into practice by the authorities in Palestine, and to discover how the Arabs reacted to this influx of Jews in the light of Ottoman official policy and practice. This study, which is based mainly on diplomatic and Jewish records, reaches the conclusion that the popular notion of Arab- Jewish harmony in Palestine prior to 1914 has little grounding in fact.</p

In-place compressive strength of concrete: statistical methods to evaluate experimental data

This paper describes a number of statistical methods to estimate, through an analysis of in-place test results, the in-place compressive strength of concrete expressed as strength of standard specimens. The evaluation of the probable existence of a linear correlation as a function of sample size is discussed. The regression laws and the degree of reliability of the estimates obtained is also discussed. A criterion is proposed for the choice of the number of points to be used in the regression. Finally a method is proposed, knowing the numberm of replicated in-place tests, to estimate the equivalent numbern of replicated tests performed on standard specimen