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

Absolute Coefficients and the Graphical Representation of Airfoil Characteristics

It is argued that there should be an agreement as to what conventions to use in determining absolute coefficients used in aeronautics and in how to plot those coefficients. Of particular importance are the absolute coefficients of lift and drag. The author argues for the use of the German method over the kind in common use in the United States and England, and for the Continental over the usual American and British method of graphically representing the characteristics of an airfoil. The author notes that, on the whole, it appears that the use of natural absolute coefficients in a polar diagram is the logical method for presentation of airfoil characteristics, and that serious consideration should be given to the advisability of adopting this method in all countries, in order to advance uniformity and accuracy in the science of aeronautics

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

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

The Caproni Seaplane

The Caproni Company recently built a seaplane of unusual design. The main supporting surfaces consisted of three triplanes in tandem, the lower wings being attached to the hull, which was described as providing accommodation for a hundred passengers. On one of the first flights, the seaplane fell into a lake, nose down, and was destroyed. The authors wish to show that this failure could have been predicted. The failure could have been predicted by applying some fundamental principles of aeronautics, especially those relating to longitudinal stability, the lack of which caused the loss of the seaplane

Optimal housing, consumption, and investment decisions over the life-cycle

We provide explicit solutions to life-cycle utility maximization problems simultaneously involving dynamic decisions on investments in stocks and bonds, consumption of perishable goods, and the rental and the ownership of residential real estate. House prices, stock prices, interest rates, and the labor income of the decision-maker follow correlated stochastic processes. The preferences of the individual are of the Epstein-Zin recursive structure and depend on consumption of both perishable goods and housing services. The explicit consumption and investment strategies are simple and intuitive and are thoroughly discussed and illustrated in the paper. For a calibrated version of the model we find, among other things, that the fairly high correlation between labor income and house prices imply much larger life-cycle variations in the desired exposure to house price risks than in the exposure to the stock and bond markets. We demonstrate that the derived closed-form strategies are still very useful if the housing positions are only reset infrequently and if the investor is restricted from borrowing against future income. Our results suggest that markets for REITs or other financial contracts facilitating the hedging of house price risks will lead to non-negligible but moderate improvements of welfare

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