The ionizing spectral energy distribution of quasars exhibits a steepening of the distribution short-ward of 1200 Å. The change of the power-law index from approximately −1 to −2 so far has been interpreted as being intrinsic to quasars. We study an alternative interpretation, in which a tenuous absorption screen is responsible for the change of index. We find that the most successful function ...

We propose a variant of hybrid inflation which is applicable in a wide class of supersymmetric grand unified models. The observed temperature perturbations of cosmic background radiation can be reproduced with natural values of the parameters of the theory and a grand unification scale which is consistent with the unification of the minimal supersymmetric standard model gauge couplings as measu...

In order to draw out the essential behavior of the universe, investigations of early universe cosmology often reduce the complex system to a simple integrable system. Inflationary models are of this kind as they focus on simple scalar field scenarios with correspondingly simple dynamics. However, we can be assured that the universe is crowded with many interacting fields of which the inflaton i...

As a part of the China-Japan cooperative research on natural radiation epidemiology, we have carried out a dose-assessment study to evaluate the external exposure to natural radiation in the high background radiation areas (HBRA) of Yangjiang in Guangdong province and in the control areas (CA) of Enping prefecture since 1991. Because of the difficulties in measuring the individual doses of all ...

In order to identify radon-prone areas and evaluate radon risk level, a soil gas radon survey combined with gamma-ray spectrometry measurements was carried out in Shenzhen City, south China. Meanwhile, the statistical analysis was applied to evaluate the distribution of measured results. This paper presents the methodology of the radon risk assessment. A radon risk map was accomplished based on...

The hot springs in special areas in Ramsar, a northern coastal town in Iran, contain (226)Ra and (222)Rn. The natural radiation effects, radiosensitivity or adaptive responses, on the inhabitants of high natural radiation in Ramsar were studied. The single cell gel electrophoresis was used to monitor DNA damages. Three groups of volunteers were selected, one from high natural background radiati...

introduction in this study, effective dose equivalent for the public due to internal exposure to 222radon (222rn) was evaluated in three regions of ramsar, a northern coastal city in iran.                                materials and methods measurements were carried out using a radon monitoring device. outdoor and indoor radon concentrations were measured within 24 hours with an integration in...

Phosphate rock samples collected from the phosphate bearing formations of Sokoto State, Northwest Nigeria were assessed for their radiological contents by gamma spectrometric technique (sodium iodide (NaI (Tl) detector). The mean activity concentrations of 226 Ra, 232 Th and 40 K in all the studied samples were 720.1±4.2 Bqkg -1 , 33.5±1.4 Bqkg -1 , and 315.3±6.7 Bqkg -1 respectively. Contribut...

in this paper are present the results of measurements of magnetic induction at some locationsin city bor (the east serbia) dating from the household electric devices and transformer stations suited near the residental areas. stress is on the extremely low frequent electromagnetic radiation from transformer stations and other high voltage instalations in urban areas. risk of the extremely low fr...