Measurements of radon in potable mineral waters along the Cota Mil Highway at two sites, La Castellana with five sampling points within 20 meters of each other and two collection points at the San Jose site were carried out from November, 1997 to December, 1998. Temporal radon variation patterns will be presented for the seven sampling points, which had very different water flow rates and short-term variations. The extraction of the radon from mineral waters was accomplished in the laboratory a few hours after sampling and the measurements were performed employing a radiation monitor with a scintillation cell 18 hours latter to insure that the radon and its decay products were in equilibrium. The results suggest that the increase of radon from the middle of February to the middle of November can be related to the decrease in atmospheric temperature and rainfall. The large differences in the minimum and maximum values of radon and the short-term variations show the need for many measurements over a year to quantify a correct annual value to be employed in dose calculation for radiological impact studies on human health. Finally, we have also concluded that water sampling points with very low water flow rates are more suitable for investigating the possible relation between radon anomalies and seismic events.
Contamination and adsorption of trace elements during storage of natural water samples in polyethylene containers have been studied. Variations of concentrations of 29 elements in pH=1.5 natural water samples stored in polyethylene bottles for 15 and 30 days respectively were determined by the method of freeze-drying preconcentration and NAA. The percentage adsorption loss of radioactive indicators60Co,124Sb,65Zn,75Se,134Cs and46Sc in the pH=1.5–8.0 reservoir water, tap water and distilled water stored for 1–2 months were also determined. The optimized storage condition for natural water is obtained.
Authors:Z. Achour-Boudjema, M. Bouroukba, D. Balesdent, E. Provost, and M. Dirand
Differential enthalpy analyses were performed on the binaryn-alkane systemn-C24H50-n-C26H54 with a Setaram DSC111 calorimeter of Tian Calvet type.
The measurements provided enthalpy data from 260 to 260 K onn-tetracosane,n-hexacosane and 19 binary mixtures.
An analytical expression, derived from the Einstein model, is proposed for every pure phase in its temperature domain, to
represent the variation in the enthalpy with temperature.
A general expression for the enthalpy as a function of temperature and composition is also given.
Dopaminergic neurons in the retina show spontaneous tetrodotoxin-sensitive pacemaking, which has been explained by a reduced Hodgkin-Huxley-type computer model. The present study used this model to investigate the effect of variations in transient and persistent sodium conductance values on pacemaking, under variable leakage conductance levels. This study indicated that transient sodium conductance plays an indispensable role in pacemaking, which occurs under conditions in which only a persistent sodium conductance is considerably reduced, thus contributing to a detailed understanding of the relationship between sodium conductance and pacemaking.
This paper deals with three classes of functions of great importance in analysis and its applications. We construct a family
of Hlder functions in the closed unit interval having two continuous parameters. Those functions are not of bounded variation
for any pair of values of the Hlder constant and exponent. The construction depends on a change of variables given by a Lipschitz
function with constant equal to 1. Several questions related to the concepts of genericity, surjectivity and deformability
are posed at the end.
Authors:G. Prasad, T. Ishikawa, M. Hosoda, A. Sorimachi, S. Sahoo, N. Kavasi, S. Tokonami, M. Sugino, and S. Uchida
Radon and thoron concentration in the outdoor environment are affected by the magnitude of the exhalation rate that can vary
diurnally and seasonally. This paper presents measurement results of radon and thoron exhalation rates and gamma-ray dose
rate in different season at same location points in Gunma Prefecture Japan. Exhalation rates were measured by the MSZ instrument
which is based on the accumulation method. Three measurement points Katashina Village, Midori City and Takasaki City were
selected for measurement. Soil water saturation and soil temperature were measured to investigate their relationship with
exhalation rate. The diurnal variation of exhalation rate may be correlated with soil temperature but no clear relationship
was found between them. The gamma-ray dose rate do not vary significantly at the same places even in different season. The
average radon exhalation rates were 11 ± 2, 2 ± 1, 5 ± 3 and 11 ± 4 mBq m−2 s−1 for spring, summer, autumn and winter, respectively. Those for thoron were 1,100 ± 100, 120 ± 30, 250 ± 80 and 860 ± 140 mBq m−2 s−1. Thus there was a variation of radon and thoron exhalation rate with different seasons. The radon and thoron exhalation rates
in the summer and autumn surveys are higher than those in the spring and winter surveys which were affected by rainfall. It
indicates that water saturation is an influential factor for radon and thoron exhalation rates.
Authors:K. Yamazaki, S. Tonouchi, and T. Hashimoto
Since October 1983, the Niigata Prefectural Government has been carrying out the continuous measurements of gamma-emitting radionuclides in the environment around the Kashiwazaki Kariwa nuclear power station by environmental radiation monitoring telemetry system. Continuous measurements of gamma-ray spectra have been established since April 1996. As a result, the contribution of various radionuclides has been gradually clarified in the variations of the gamma-ray dose rate. In this paper, the energy spectrum of the incident gamma-ray to NaI(Tl) scintillation detector was obtained by the unfolding method using a response matrix, and the variations of the energy spectrum observed in the precipitation and snow were investigated. The increase in the dose rate in precipitation originated from the increase in the flux density of gamma-ray from 214Bi and 214Pb, daughter nuclide of 222Rn, which fell down with the precipitation. On the other hand, the reduction in the dose rate in the snowy period was confirmed due to the shielding effect of a part of gamma-rays from the natural radioactive nuclides by the snow layer, in coincidence with the decrease of the flux density in 40K and 208Tl.
Authors:Young Cho, Wanno Lee, Kun Chung, Geun Choi, and Chang Lee
The seasonal variation of the 7Be activities in air and the size distribution of the 7Be aerosols were studied by using a continuous air sampler and a five stage cascade impactor. The mean monthly activity level
of 7Be at the Korea Atomic Energy Research Institute (KAERI) site varied from 0.5 to 4.8 Bq·m−3 and revealed a seasonal variation, in which the 7Be activity levels were high in winter and low in summer. The mass size distribution showed a bi-modal distribution with a
higher peak around 0.49 μm and a smaller peak between 3 μm and 7.2 μm. The activity median aerodynamic diameter (AMAD) decreased
with increasing ambient 7Be concentrations. The mean residence times by using a mean growth rate of 0.004 μm·h−1 were estimated to be 2.5–6.4 days. The AMAD has an increasing tendency with higher relative humidity. It seemed that the
high humidity condition facilitated the growth of the aerosol, resulting in increased deposition rates of the aerosols and
the low 7Be content in the surface air. The AMAD of the 7Be aerosols increased with an increasing temperature, but the temperature dependency of AMAD should be explained with geological
and meteorological conditions.
A wheat (Triticum aestivum L.) immature spike culture system was used to expeditiously generate mutations for use in wheat improvement programs. Wheat immature spikes in culture were treated with three concentrations of ethylmethane sulphonate (EMS) to generate a spike culture derived variant (SCDV) population. EMS in a concentration dependent manner affected seed development in wheat immature spike cultures. Based on the number of seeds produced, inclusion of EMS (25 mM) for three hours in immature spike culture medium generated variants in wheat cv. AC Nanda. The wheat AC Nanda SCDV population showed variation in several phenotypic characters. Flag leaf (length, angle and sheath length), length of first and second internode, spike length, number of spikes, number of seeds per spike and seed weight, showed variation below and above the non-treated controls. A molecular screening technique combining simple sequence repeat (SSR) oligonucleotide primers with high resolution melt (HRM) PCR with EvaGreen was used to identify the variants. Screening for starch branching enzyme IIb (SbeIIb) revealed 75 lines with point mutations. Combining SSR and SbeIIb, a total of 100 Kbp portion of wheat DNA was screened. The estimated mutation frequency in SbeIIb was one per 20.8 Kbp. The spike culture system utilizes very small amounts of EMS for a brief period, thus needs minimal handling of EMS and saves one generation of plant growth in a greenhouse. The morphological variants observed are similar to those reported for seed-derived variants using EMS.
Authors:András Gáspárdy, Viktoria Holly, Petra Zenke, Ákos Maróti-Agóts, László Sáfár, Ágnes Bali Papp, and Endre Kovács
The authors studied the present status of Hungarian indigenous sheep breeds based on the genetic background of scrapie resistance. The aim of this investigation was to estimate the relative frequency of prion haplotypes, genotypes and risk categories, as well as to reveal the efficiency of the scrapie eradication programme achieved over the last decade. A novel approach in the characterisation of prion by using its genic variation was also implemented. The authors established that the proportion of deleterious sites (%) can be a useful indicator of the eradication programme. Based on a large sample size, it was confirmed that the scrapie resistance of the Cikta breed is low, and the classification of this breed according to risk category has not improved. However, the frequent genotype ARQ and risk category 3 can also be considered characteristic of the breed. The careful use of these genotypes is permitted and will contribute to the maintenance of breed diversity. The response of prion genic variation to selection for scrapie resistance in the other breeds (Tsigai, Milking Tsigai, White Racka, Black Racka and Gyimes Racka) was definitely successful.