Norwegian Series Research Articles

Atheroma of the larger arteries of the brain in a Polish population: A study of 600 cases

1. (1) Studies were carried out upon a series of 600 unselected patients between the age-limits of 11–99 who died in the first State University Hospital in Warsaw. 2. (2) In 31.3% of cases there were no atheromatous changes in the larger cerebral arteries; in the remaining 68.7% of the subjects examined there were degenerative vascular changes which were classified as mild atheroma in 29.8%, in 11.5% as moderate, and in 27.3% as severe. 3. (3) Atheromatous changes were first found in cases in the third decade of life. After that age the number of cases with brain atheroma was found to increase gradually according to the patient's age. At the same time there was a definite shift within the spectrum of atheroma from changes classified as mild to those of severe degree. 4. (4) The internal carotid arteries, the anterior and posterior portions of the basilar artery, and the middle cerebral arteries were the ones most severely involved. The degenerative atheromatous changes occurred in these situations most often and most early. In cases with mild atheroma there was clear-cut selectivity as to localization of atheromatous changes for the above-mentioned arteries; as the intensity of atheroma increased, the degenerative changes were also seen to occur in other regions of the cerebral arterial tree. 5. (5) There was no great difference in the frequency and intensity of atheromatous changes in the brain arteries, with regard to sex. 6. (6) A comparison was made with the results obtained and the data presented by Baker et al. in their American and Norwegian series.

A study on the secular variation of magnetic elements based on data forD,I, andHfor Oslo, 1820-1948

An attempt is made to get a general view of the secular variation of the most important magnetic elements for as long a time as possible. Those elements are D, I, H, X, F, Z, and F. For D the annual data are given for the entire interval 1770–1948 and for the rest 1820–1948. It is quite clear that at a station where, since 1890, modern photographic registering instruments are mounted, more exact data are obtained for the magnetic elements, especially where details are concerned, but also here the homogeneity might be questionable, because some of the most important observatories have been forced to change from one place to another (often considerably removed from the original site). There is also to be considered the question of the quality of the absolute observations used for the reductions. It must be remembered that there has been opportunity to compare standards only in recent years. A change of instrument and change of place, where the absolute observations were taken, may influence the homogeneity and the larger gaps may also be serious. Comparing the Oslo material with that of other stations, one gets the impression that the Norwegian series—thanks to Hansteen's imposing work—is the most complete and not worse in regard to homogeneity than other old series. The relative H-instrument has continued unaltered and uninterrupted from 1843–1930, and the reduction is based on absolute observations taken on the same pier during all these years and with Hansteen's standard magnet—most of the time by Hansteen personally. In D the conditions are not so favorable, but all are fairly good. The I-series is probably also fairly homogeneous between 1870 and 1908, but there is a deplorable gap between 1908 and 1948. No registrations are at hand before 1870 for I and before 1843 for D and H. Nevertheless, annual data for D from 1770 and for H and I from 1820 have been found in several series of absolute observations. The technique used for interpolation and extrapolation is fully explained. The most serious gap is the one for I during 1908 to 1948, but also in this case the results are not far from true. As to Hansteen's absolute observations, one is impressed by the quality he actually obtained with the primitive instruments he used.

The aurora and night‐sky spectra and the upper atmosphere—Report on recent work

Fairly complete accounts of the data relating to the auroral spectrum and the state of the upper atmosphere obtained by the writer and his collaborators up to 1933 have been published in a number of papers in the Norwegian series of Geophysical Publications [see references 1, 2, and 3 at end of paper]. During the last few years the writer, in collaboration with L. Harang and E. Tonsberg at the Auroral Observatory, Tromso, has devoted much attention to the following problems:(a) To find means for increasing the accuracy of our wave‐length determinations especially in the region of long waves(b) To make clear the intensity‐variations within the auroral spectrum with respect to varying altitude, type, and color(c) Comparison of the auroral spectrum with that of the night sky(d) The determination of the temperature of the auroral region by means of the nitrogen‐bands appearing in the auroral spectrum