Relationship between X-ray Exposure and Patient Dose on the Radiological Diagnosis

Patient dose is important consideration in the radiological examination and our environment regarding radiation. Many studies have been published about patient dose, but those data were classified by each organ or tissue. Actuarially, patient dose should be checked by each examined part of patient and each exposure equipment. In this paper, we measured absorbed dose at the depth of 0-200mm with the Mix-DP phantom. The phantom is made by tissue equivalent meterial and is designed to similitude abdominal part. Percentage Depth Dose (PDD) was calculated from these doses. Three single-phase generators and three three-phases generators were used in this measurement. These measurements were analyzed by each equipment, and consequently the clear difference of PDD between the exposure equipments was not found. As the result, we can estimate patient dose at a random depth by using PDD. Furthermore, we can easily know patient dose from the tube-voltage and current time product by the calculation including PDD.These data are very useful to manager patient dose on radiological diagnosis

Nitrogen Uptake by the Rice Plant and Changes in the Soil Chemical Properties in the Paddy Rice Field during Yearly Application of Anaerobically-Digested Manure for Seven Years

This study investigated the changes in the chemical properties of the plow soil during a 7-year period with yearly application of anaerobically-digested manure (ADM), and the effect of the different ADM application methods on nitrogen (N) uptake by rice plants and the apparent N balance (input N minus output N). Among the treatments significant differences were observed in the pH, total N, and available N in the plow soil. The cumulative N uptake by rice plants in the ADM split application plots was significantly higher than that in single application plots. Consequently, the apparent N balance (input N minus output N) in the single ADM application plots was more positive. This result suggests that split application of ADM is more favorable for N uptake by rice plants. Although the apparent N balance was negative in the plots without N fertilizer, with chemical N and with low ADM, there was no observable decline in the total N and available N in the plow soil. This result implies that input and output of N in these plots were well balanced by additional N supply other than fertilization. On the other hand, the apparent N balance during the 7-year study under standard and heavy application of ADM was positive, indicating the preservation of soil fertility

Comparison of Root System Development in Two Rice Cultivars During Stress Recovery from Drought and the Plant Traits for Drought Resistance

A greenhouse experiment was conducted to compare root system development of two upland rice cultivars, IRAT 13 and Senshou, during recovery from drought stress and to identify the plant traits that confer drought resistance. From 62 days after sowing (62 DAS), drought stress was given for 6 d followed by rewatering for 14 d. Root length density (RLD) and root diameter (thickness) were measured at the end of the stress and rewatering periods. Control plants were well-watered throughout the study. Gultivar IRAT 13 had thicker roots and higher relative RLD (ratio of RLD in drought-stressed plants to that in control plants) than under drought stress, and significantly higher root growth recovery after rewatering cultivar Senshou. Related plant traits such as evapotranspiration (ET), leaf and stem dry weights and weight of senescent leaves (dead leaves) in IRAT 13 were significantly more favorable for drought resistance compared to Senshou

Path Analysis of Tiller Density of Winter Wheat Demonstrates the Importance of Practices that Manipulate Clod Size Based on Soil Moisture at Seeding in the Rice–Wheat Cropping System

The moisture of paddy soil after rice cropping is a major impediment to the establishment, tillering and yield of winter wheat in the rice−wheat (R−W) cropping system. We examined the seedling establishment ratio, based on soilmoisture at seeding by path analysis of nine soil/plant traits in the farmer's fields in Western Japan where the R−W cropping system was being used, to establish a strategy for improving tiller density by optimizing the seedling establishment ratio. The clod size of surface soil, which showed a significant positive correlation with soil moisture at seeding, had a significant negative direct effect on the seedling establishment ratio. The reduction in seedling establishment ratio, together with fewer tillers per plant, resulted in a significant decrease in tiller density. The sum total of contribution of soil moisture contents to tiller density via clod size was smaller than that of seeding rate, and similar to that of the amount of nitrogen (N) basal dressing. This indicates that manipulating clod size based on soil moisture at seedingprovides an opportunity for maintaining tiller density, as well as changing the amount of N basal dressing with the soil moisture conditions after rice cropping

Correlation of the Amount of Nitrogen Accumulated in the Aboveground Biomass at Panicle Initiation and Nitrogen Content of Soil with the Nitrogen Uptake by Lowland Rice during the Period from Panicle Initiation to Heading

To estimate the site-specific optimal amount of nitrogen (N) to be applied as top-dressing (N top-dressing) at panicle initiation, we examined the effects of the amount of N accumulated in the aboveground biomass at the panicle initiation stage (NJ, the total N content of soil and the amount of mineralizable soil N (Nm) on the amount of soil N taken up by the plants during the period from panicle initiation to heading (Ns) and the recovery ratio of applied chemical N during this period (J). We analyzed the data obtained in paddy fields with a similar soil type and weather condition in the growth period from 1999 to 2001. The growth of rice plants was regulated by the amounts of N applied before transplanting and at panicle initiation. The relative N uptake rate during the period from panicle initiation to heading (RNR) in the plots without N top-dressing was explained about 89% by multiple regression of N„ the total N of soil and Nm. Ns in the plots with N top-dressing that was estimated using RNR showed a significantly negative partial correlation with N1; the total N of soil and Nm. J in the plots with N top-dressing showed a significantly negative partial correlation with N1: but a significantly positive partial correlation with Nm. These results suggest that the fertilizer N should be applied considering the contribution of Nl5 the total N content of soil and Nm to Ns and J to fit the site-specific N demand of rice