A study of Dykstra-Parsons curves

The Dykstra-Parsons method for prediction of oil recovery by water flooding is a well known technique which has been used by the petroleum industry since 1945. The present work carries their study further, solving the same problem of calculating coverage for certain values of permeability variation having water-oil-ratio and mobility ratio as fixed parameters. The work herein, instead of using 50 layers, uses 200. Also a more precise theoretical approach to the problem is given. Because of these differences the resulting curves are slightly modified. In a second part, the authors deal with empirical simplifications with considerable success. The idea was to collapse the data and curves obtained in the first part into a single curve which covers most of the range of variables commonly seen in reservoir displacements

Alguns aspetos fiscais das operações de reestruturação empresarial: o regime especial de neutralidade fiscal em sede de IRC

Uma reorganização empresarial deve ter por base motivos económicos, ser orientada pela obtenção de eficiências ao nível da atividade económica, e não ter em vista essencialmente a obtenção de ganhos fiscais. Atendendo à sua natureza, estas operações geram por vezes fluxos financeiros que podem ser interpretados fiscalmente como a realização de ganhos das empresas que foram objeto de reorganização e serem estas tributadas em sede de IRC, mas sem que se tenha efetivamente realizado esse ganho, o que pode representar um obstáculo à realização destas operações. Para evitar que a fiscalidade se constitua como um entrave à obtenção de eficiência das empresas existem situações em que os ganhos realizados nessas operações não são reconhecidos imediatamente em termos fiscais, sendo a sua tributação diferida para mais tarde. Essas situações encontram-se previstas na lei fiscal nacional e comunitária e enquadram-se no regime especial da neutralidade fiscal que institui um regime tributário neutro aplicável a este tipo de operações. Não obstante o regime especial da neutralidade fiscal facilitar as reestruturações empresariais através de um sistema de tributação neutro constituindo um importante mecanismo de dinamização do tecido económico e empresarial, o sistema atual apresenta algumas fraquezas ao nível da prevenção das situações de evasão fiscal.A business reorganization must be based on economic reasons and be guided by the achievement of efficiencies in terms of economic activity, and not just essentially aim at the obtainment of tax gains. In view of their nature, these operations sometimes generate financial flows that can be interpreted for tax purposes as the realization of gains from companies that have been the subject of reorganization and that these are taxed under IRC, but without that gain actually being realized, which may represent an obstacle to these operations. In order to avoid that taxation constitutes an obstacle to obtaining companies' efficiency, there are situations in which the gains realized in these operations are not immediately recognized in tax terms, and their taxation is deferred for later. These situations are provided for in national and community tax law, and are part of the special tax neutrality regime that establishes a neutral tax regime applicable to this type of transactions. Despite the special tax neutrality regime facilitating business restructuring through a neutral taxation system, constituting an important mechanism to boost the economic and business fabric, the current system still presents some weaknesses in terms of preventing tax evasio

Teleworking practice in small and medium-sized firms: Management style and worker autonomy

In an empirical study of teleworking practices amongst small and medium-sized enterprises (SMEs) in West London, organisational factors such as management attitudes, worker autonomy and employment flexibility were found to be more critical than technological provision in facilitating successful implementation. Consequently, we argue that telework in most SMEs appears as a marginal activity performed mainly by managers and specialist mobile workers

What We Don't Know about BTZ Black Hole Entropy

With the recent discovery that many aspects of black hole thermodynamics can be effectively reduced to problems in three spacetime dimensions, it has become increasingly important to understand the ``statistical mechanics'' of the (2+1)-dimensional black hole of Banados, Teitelboim, and Zanelli (BTZ). Several conformal field theoretic derivations of the BTZ entropy exist, but none is completely satisfactory, and many questions remain open: there is no consensus as to what fields provide the relevant degrees of freedom or where these excitations live. In this paper, I review some of the unresolved problems and suggest avenues for their solution.Comment: 24 pages, LaTeX, no figures; references added, brief discussion of relation to string theory added; to appear in Class. Quant. Gra

Genes Suggest Ancestral Colour Polymorphisms Are Shared across Morphologically Cryptic Species in Arctic Bumblebees

email Suzanne orcd idCopyright: © 2015 Williams et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited

Effects of Propofol on Endotoxin-Induced Acute Lung Injury in Rabbit

This study was undertaken to clarify the effects of propofol on endotoxin-induced acute lung injury. Rabbits were randomly assigned to one of four groups. Each group received intravenous infusion of saline only, saline and Escherichia coli endotoxin, propofol (1 mg/kg bolus, then 5 mg/kg/hr) and endotoxin, or propofol (4 mg/kg bolus, then 20 mg/kg/hr) and endotoxin respectively. Infusion of saline or propofol was started 0.5 hr before the infusion of saline or endotoxin, and continued for 6 hr thereafter. The lungs of rabbits were ventilated with 40% oxygen. Mean blood pressure, heart rate, arterial oxygen tension (PaO2), and peripheral blood leukocyte and platelet count were recorded. The wet/dry (W/D) weight ratio of lung and lung injury score were measured, and analysis of bronchoalveolar lavage fluid (BALF) was done. Endotoxin decreased PaO2, and peripheral blood leukocyte and platelet count. And it increased W/D ratio of lung, lung injury score and leukocyte count, percentage of PMN cells, concentration of albumin, thromboxane B2 and IL-8 in BALF. Propofol attenuated all these changes except the leukocyte count in peripheral blood. In conclusion, propofol attenuated endotoxin-induced acute lung injury in rabbits mainly by inhibiting neutrophil and IL-8 responses, which may play a central role in sepsis-related lung injury