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In this work we will present a new set of photon fluence-to-effective dose conversion coefficients using the Saudi population-based voxel phantom developed recently by our group. The phantom corresponds to an average Saudi male of 173 cm tall weighing 77 kg. There are over 125 million voxels in the phantom each of which is 1.37×1.37×1.00 mm 3 . Of the 27 organs and tissues of radiological interest specified in the recommendations of ICRP Publication 103, all but the oral mucosa, extrathoracic tissue and the lymph nodes were identified in the current version of the phantom. The bone surface (endosteum) is too thin to be identifiable; it is about 10 μm thick. The dose to the endosteum was therefore approximated by the dose to the bones. Irradiation geometries included anterior–posterior (AP), left (LLAT) and rotational (ROT). The simulations were carried out with the MCNPX code version 2.5.0. The fluence in free air and the energy depositions in each organ were calculated for monoenergetic photon beams from 10 keV to 10 MeV to obtain the conversion coefficients. The radiation and tissue weighting factors were taken from ICRP Publication 60 and 103. The results from this study will also be compared with the conversion coefficients in ICRP Publication 116.

Fluence-to-dose conversion coefficients are important quantities for radiation protection, derived from Monte Carlo simulations of the radiation particles through a stylised phantom or voxel based phantoms. The voxel phantoms have been developed for many ethnic groups for their accurate reflection of the anatomy. In this study, we used the Monte Carlo code MCNPX to calculate the photon fluence-to-effective dose conversion coefficients with a voxel phantom based on the Saudi Arabian male population. Six irradiation geometries, anterior-posterior (AP), posterior-anterior (PA), left lateral (LLAT), right lateral (RLAT), rotational (ROT) and isotropic (ISO) were simulated for monoenergetic photon beams from 10 keV to 20 MeV. We compared the coefficients with the reference values in ICRP Publication 116. The coefficients in the AP and PA geometries match the reference values to 9% and 12% on average as measured by root mean square while those in the LLAT, RLAT ROT and ISO geometries differ, mostly below, from the reference by 23, 22, 15 and 16%, respectively. The torso of the Saudi phantom is wider than the ICRP reference male phantom and likely to cause more attenuation to the lateral beam. The ICRP reference coefficients serve well for the Saudi male population as conservative estimations for the purpose of radiation protection.

Monthly average daily measurements over a three-year period (1985–1987) for eight weather parameters are reported. The computed three-year averages of total yearly global radiation, diffuse radiation, hemispherical global infrared radiation, and global UV radiation were 1,939.08, 696.82, 3,144.30, and 87.78 kWh/m2, respectively. Further, employing least-squares linear regression analysis, empirical fits expressing the monthly average daily measurements as a function of month of the year were developed for seven weather parameters.

A strong pyrene emission was observed when certain block, alternate, and random butadiene–styrene-based rubber films were subjected to intense UV irradiation in vacuum. Weak or no pyrene emission was obtained from the same films when they are irradiated in the presence of O2. A mechanistic scheme leading to pyrene formation in these samples is given together with qualitative explanation of the dependence of pyrene formation on sample composition.

DESPITE the precautions undertaken to secure better hatchability, some eggs fail to hatch. Such eggs represent a great loss for both hatchery men and breeders. This experiment was done to study embryonic mortality and malpositions in Fayoumi. REVIEW OF LITERATURE A. Embryonic Mortality. Embryonic mortality occurs at any time from fertilization up to the time of hatching. Payne (1919) found that there was two peaks of embryonic mortality and reported that 65 percent of all embryonic mortality occurs between the fourth and the sixth day of incubation. In contrast, Byerly (1930) found that the first peak occurred on the third day of incubation. Byerly et al. (1934) reported that there was a minor peak at about the seventh day of incubation. Later on, they found another peak in the middle of the incubation period, which was related to nutritional deficiencies in the diet consumed by the flock. They also reported …

OCCASIONALLY some eggs are laid which contain varying amounts of blood and meat spots. Such eggs are of a low market quality and are unattractive as food. A study was directed to these abnormal eggs and rejects. REVIEW OF LITERATURE Van Wagnen, Hall and Wilgus (1937), reported that the frequency of meat spots varies with breeds. Jeffrey (1945), found a difference between Leghorn and heavy breeds. Dawson et al. (1945), reported that heredity was an important factor in the production of eggs containing blood spots. Jeffrey and Pino (1943), reported that the belief that blood spots result from the hens being frightened was untrue. Carlson (1957), observed that there was a higher percentage of blood spots among caged layers than among birds of the same variety in convential floor pens. Burmester and Card (1938), stated that meat spots are really degenerated blood spots. Nalbandov and Card (1944), found that their…

INTRODUCTION ONE of the main suggestions to solve the problem of the shortage of both eggs and meat in Egypt is to import and adapt the high yielding foreign breeds of poultry. The author follows up his study of three commercial strains imported from Holland and the native strain known as Fayoumi. Amer (1956) compared the foreign breeds and Fayoumi with respect to fertility, hatchability, body weight and body measurements. Later on, Amer (1964), made a comparison between the previous breeds and the local strain with respect to annual egg production and mode of laying. This paper deals with the study of age at sexual maturity, body weight at sexual maturity and egg size in the standard breeds and Fayoumi. REVIEW OF LITERATURE Sexual Maturity: Byerly and Knox (1946) reported that pullets of later hatches laid their first egg at older ages than those of earlier hatches. They added that…

INTRODUCTION SELECTION is considered to be the best tool for genetic improvement in a given population. Heritability of a character is an important factor affecting genetic improvement. In a previous paper, Issawi et al. (1963) studied heritability of fertility and hatchability in Fayoumi. The present paper deals with the study of heritability of body weight in Fayoumi. REVIEW OF LITERATURE Many investigators estimated heritability of body weight in chickens. Spector (1956) summarized the different estimates of this character and concluded that it was highly heritable. In Single Comb White Leghorn, Lerner et al. (1949) stated that heritability of body weight at twelve weeks of age was 0.475, and 0.597 and 0.506 on the basis of the contribution of sire, dam, and both, respectively. Fagan (1949), reported similar figures for heritability of body weight at twelve weeks of age, being in the range from 0.35–0.50. El-Ibiary and Shaffner (1951), reported…

Polynuclear aromatic hydrocarbons (PAH) are among the most dangerous pollutants in the Arabian Gulf region. They are produced in the atmosphere as a result of incomplete combustion and pyrolysis of fossil fuels and other organic materials. Their main sources, in that part of the world, are the petrochemical industry and the ever-increasing number of cars in the region. There exists no pollution control system for either the factories or cars, thus causing a continual environmental loading by PAH.