Serum beta-glucuronidase determination in normal subjects and in neurological and mental patients, a provisional report

Using the method given by GOLDSTEIN (1961)9 for the determination of serum beta-glucuronidase activity, this value was determined in both normal and patients with epilepsy, neuroses, psychoses and multiple sclerosis. Of the patient groups examined, the group of those suffering from epilepsy is the only one showing any difference of statistical significance for all four methods of determination. The group of patients suffering from neuroses differs significantly from the normal group as regards the results got by the method of heat coagulation for removal of the proteins. The material is however too small to provide any explanation of the results, but it appears to show that a determination of serum glucuronidase activity may be of interest in groups of diseases other than malignant tumors.</p

On a new type of wind tunnel

Discussed here is a new type of wind tunnel, its advantages, the difficulties attendant upon its use, and the special methods required for its operation. The main difference between the new type of wind tunnel and the ones now in operation is the use of a different fluid. The idea is to diminish the effect of viscosity If air is compressed, it becomes a fluid with new properties - a fluid that is best suited for reliable and exact tests on models. When air is compressed, its density increases, but its viscosity does not. It is argued that the increase of pressure greatly increases the range and value of wind tunnel tests. Reynolds number, deductions from the Reynolds law, the causes of errors that result in differences between tests on models and actual flights, and the dimensions of a compressed air wind tunnel are covered

A "Double Dividend", After All?

The consensus view among economists seems to be that a green tax reform is unlikely to be associated with a "double dividend" (Bovenberg 1998). However, the results derived in the present paper suggest that this view needs to be qualified. We demonstrate that a green tax reform is likely to be associated with a significant "double dividend" if the government prior to taking the environmental aspect into account has adopted a proportional tax structure due to the administrative costs involved in differentiating commodity tax rates, and if the green tax reform stimulates the labour supply and has desirable income distributional effects.Optimal taxation, externalities, administrative costs, green tax reform, double dividend

Comparing the GG-Normal Distribution to its Classical Counterpart

In one dimension, the theory of the $G$-normal distribution is well-developed, and many results from the classical setting have a nonlinear counterpart. Significant challenges remain in multiple dimensions, and some of what has already been discovered is quite nonintuitive. By answering several classically-inspired questions concerning independence, covariance uncertainty, and behavior under certain linear operations, we continue to highlight the fascinating range of unexpected attributes of the multidimensional $G$-normal distribution.Comment: Final version. To appear in Communications on Stochastic Analysis. Title has changed. Keywords: sublinear expectation, multidimensional $G$-normal distribution, independenc

Welfare Effects of Tax and Price Changes Revisited

Dixit’s 1975 paper ‘Welfare Effects of Tax and Price Changes’ cosntitutes a seminal contribution to the theory of tax reform analysis within a second-best general equilibrium framework. The present paper clarifies ambiguities with respect to normalisation which have led to misinterpretation of some Dixit’s analytical results. It proves that a marginal tax reform starting from a proportional tax system will improve social welfare if it increases the supply of labour, whatever the rule of normalisation adopted, and shows that this result provides the key to understanding what determines the optimal system of commodity taxation as reflected in the Corlett and Hague analysis of optimal taxation in an economy with two produced commodities. Recasting work by Deaton (1981b), it generalises, using an alternative definition of the complementarity between consumption and leisure, to an economy with many commodities the insight that the optimal tax system is determined as a trade-off between two objectives : 1) to encourage the supply of labour to the market, and 2) to limit the distorsion of the pattern of consumption of produced commoditie. This insight cannot be illustrated by simulation studies using standard additive separable utility functions. However, extending work of Atkinson and Stern (1080,1981) the paper presents a parameterised utility function with explicit representation of the use of time, the CES-UT, which allows a flexible representation of the relationship between consumption and leisure. This functional form is used to provide a quantitative illustration of the trade-off which defines the optimal tax system and thus desirable directions of tax reform.Public economics, optimal taxation, tax reform, tax simulation, distance functions, CGE models

Identifiability for Blind Source Separation of Multiple Finite Alphabet Linear Mixtures

We give under weak assumptions a complete combinatorial characterization of identifiability for linear mixtures of finite alphabet sources, with unknown mixing weights and unknown source signals, but known alphabet. This is based on a detailed treatment of the case of a single linear mixture. Notably, our identifiability analysis applies also to the case of unknown number of sources. We provide sufficient and necessary conditions for identifiability and give a simple sufficient criterion together with an explicit construction to determine the weights and the source signals for deterministic data by taking advantage of the hierarchical structure within the possible mixture values. We show that the probability of identifiability is related to the distribution of a hitting time and converges exponentially fast to one when the underlying sources come from a discrete Markov process. Finally, we explore our theoretical results in a simulation study. Our work extends and clarifies the scope of scenarios for which blind source separation becomes meaningful

Remarks on the Pressure Distribution over the Surface of an Ellipsoid, Moving Translationally Through a Perfect Fluid

This note, prepared for the National Advisory Committee for Aeronautics, contains a discussion of the pressure distribution over ellipsoids when in translatory motion through a perfect fluid. An easy and convenient way to determine the magnitude of the velocity and of the pressure at each point of the surface of an ellipsoid of rotation is described. The knowledge of such pressure distribution is of great practical value for the airship designer. The pressure distribution over the nose of an airship hull is known to be in such good agreement with the theoretical distribution as to permit basing the computation of the nose stiffening structure on the theoretical distribution of pressure

On the Use of Border Taxes in Developing Countries

Contrary to what is implied by the so called “Wahsington consensus”, Stiglitz (2003) has argued that in the least developed countries border taxes are superior to VAT. However, supported by much respectable research, the IMF and World Bank’s recommend that developing countries substitute VAT for border taxes. The present paper provides an easy to implement parameterised general equilibrium model which may be used as the basis for empirical research, required to reach a consensus opinion within the profession on the issue. The model allows for the fact that different tax systems are associated with different administrative costs, and represents the informal sector as a parameterisation, the CES-UT, of a utility function with explicit representation of the use of time. By means of a quantitative example, it illustrates, on the one hand, that a large informal sector in itself does not justify the use of border taxes, but, on the other hand, when administrative costs of taxation are taken into account, that the size of the informal sector, as claimed as Stiglitz (2003), is indeed important for whether the use of border taxes is desirable or not.Optimal trade policy, VAT, tax-tariff reform, costs of tax administration, informal sector, developing countries