Irregular Intensity Research Articles

Holographic image formation using phase plates with incoherent imaging property

An incoherent image synthesis method using a recently developed grating modulated phase plate has been presented in order to reduce unwanted noise components in the reconstructed images. A study in connection with this method leads us to the analytical derivation of a desirable phase plate with a specified phase sequence. The analytical description presented here, with particular emphasis on obtaining the imaging property in coherent holographic imagery identical to that in incoherent imagery, shows that the derived phase plate enables us to get the reconstructions with far less undesirable irregular intensity fluctuations or noiselike pattern. Some experimental confirmations are given to make sure of the analysis.

OSO-7 observations of the X-ray nova 3U 1543-47

The intensity and spectrum of the transient X-ray source 3U 1543-47 were measured by X-ray detectors on the OSO-7 satellite on 13 occasions between November 1971 and December 1972. The results, together with observations of the same object by the Vela and Uhuru satellites, can be described in terms of four qualitatively distinct phases in the X-ray light curve: (1) outburst; (2) relatively steady intensity and spectrum; (3) rapid decrease in intensity and decrease in apparent temperature; and (4) irregular intensity fluctuations with complex spectra. The term 'X-ray nova' is proposed to characterize this and similar transient sources, and a new model for such X-ray novae is proposed.

Long-term Intensity Variations of Pulsars observed at Two Frequencies

PULSARS are known1,2 to exhibit irregular intensity variations with time-scales of weeks and months. For pulsars CP 0808, CP 0834 and CP 1919 the observations have been continued at 81.5 MHz and extended to 151 MHz. A comparison of the daily intensities at the two frequencies has established that they are correlated.

Cosmic Radiation Intensity-Time Variations and Their Origin. II. Energy Dependence of 27-Day Variations

Cosmic-ray intensity-time variations recorded in the lower atmosphere by one neutron detector (D-1, Climax, Colorado) and three ionization detectors (Freiburg, Germany; Cheltenham, Maryland; and Huancayo, Peru) are compared. Irregular intensity variations characterized by time parameters of 27 days and 24 hours are shown to occur in coincidence in the records of both types of detectors. It seems reasonable to ascribe correlated neutron and ionization intensity variations to a common origin.It has been shown that 27-day neutron intensity variations are produced by primary intensity variations. The magnitude of these variations must be greater for low energy primaries as 27-day neutron intensity variations at Climax are \ensuremath{\approx}5 times larger than corresponding ionization intensity variations at Freiburg, Cheltenham, and Huancayo. These variations must extend, however, to high energy primaries, as their effects are observed at the geomagnetic equator. From the \ensuremath{\approx}5:1 relative response (Climax neutron to northern sea level ionization detector) one parameter describing the energy dependence of 27-day primary intensity variations can be empirically evaluated. Assuming a power law similar to that describing the energy dependence of the time average primary intensity spectrum, it is found that the amplitude of 27-day primary intensity variations is required to decrease with increasing primary energy approximately one power of energy more rapidly than the time average primary spectrum itself. The electric field acceleration process hypothesis predicts primary intensity variations with approximately this energy dependence.Twenty-four-hour neutron (Climax) and ionization (Freiburg) intensity variations are correlated in local time. It is not certain that these variations are produced by primary intensity variations. Even if this were the case, the relative response (Climax to Freiburg) to such primary intensity variations cannot be accurately determined from the data studied here.

EXPERIENCES WITH INTRAMEDULLARY TRACTOTOMY

The new operation of intramedullary tractotomy (Sjoqvist) has reawakened an interest in the anatomic arrangement and physiologic functions of the fibers composing the descending tract of the trigeminal nerve. Current ideas on these matters have been derived largely from clinicopathologic observations in cases of thrombosis of the posterior inferior cerebellar artery and of syringobulbia in which the intramedullary trigeminal fibers were involved in the pathologic process. Lesions of this character, because of their irregular size and intensity of destruction, have obvious disadvantages when a study of the clinical effects relating to impairment of a single structure or of an isolated tract is desired. Surgical transection of the descending tract of the trigeminal nerve in man, performed by means of a small controlled incision into the tuberculum cinereum, obviates many of the former difficulties and allows for the first time correlation of sensory changes with a small lesion accurately placed in