ABSTRACT
The main objective of this work is to simulate the X-ray scattered spectra by different pediatric phantoms (simulation of children subjected to barium meal procedures) to calculate an energy correction factor (ECF) to the reading of thermoluminescent dosimeters (TLDs). To perform this evaluation, the TLDs were positioned over three areas in two occupational workers: eyes, thyroid and hands. The Geant4 toolkit was used to define the spectra collected by TLDs, making possible to calculate the ECF. This work was developed in two stages: (1) evaluation of scattered spectra by different standard phantoms (newborn, 1, 5 and 10 years old); (2) definition of the ECF to the absorbed energy by each TLD. Geant4 shows to be a good toolkit to calculate the ECF and among the different characteristics evaluated, in this work, the TLD position and acceleration voltages are the most significant parameters that may influence the ECF calculated.
Subject(s)
Occupational Exposure/analysis , Pediatrics/methods , Radiation Exposure , Thermoluminescent Dosimetry/instrumentation , Barium Sulfate/administration & dosage , Child , Child, Preschool , Eye/radiation effects , Fluoroscopy , Hand/radiation effects , Humans , Infant , Infant, Newborn , Monte Carlo Method , Phantoms, Imaging , Scattering, Radiation , Thyroid Gland/radiation effectsABSTRACT
A total of 128 adrenalectomies were made for catechol-producing tumor (n = 69), mineralocorticism (n = 27), primary and metastatic adrenal cancer (n = 20), other tumors (n = 12). A stable hypotensive result after adrenalectomy was observed in 97.1, 66.8% patients with pheochromocytoma and mineralocorticism, respectively. The rest patients improved, i.e. their malignant hypertension converted to a benign one. If cancer involves the upper segment of the kidney, the tumor often invades the adrenal. Therefore, pre- and intraoperative search for adrenal tumor must be made.
Subject(s)
Adrenal Gland Neoplasms/diagnosis , Adrenal Gland Neoplasms/surgery , Adrenalectomy , Hypertension/surgery , Adrenal Gland Neoplasms/complications , Humans , Hypertension/diagnosis , Hypertension/etiology , Treatment OutcomeABSTRACT
This article presents a self-organising multilayered iterative algorithm that provides linear and non-linear polynomial regression models thus allowing the user to control the number and the power of the terms in the models. The accuracy of the algorithm is compared to the partial least squares (PLS) algorithm using fourteen data sets in quantitative-structure activity relationship studies. The calculated data show that the proposed method is able to select simple models characterized by a high prediction ability and thus provides a considerable interest in quantitative-structure activity relationship studies. The software is developed using client-server protocol (Java and C++ languages) and is available for world-wide users on the Web site of the authors.
Subject(s)
Internet , Neural Networks, Computer , Quantitative Structure-Activity Relationship , Models, Statistical , Regression Analysis , SoftwareABSTRACT
Certain properties of the map as a model are briefly examined. Use of the cartographic model in hygiene largely depends on space characteristics of the events and processes being studied. Hygiene as a science introduces into the map new, specific contents and a methodology that includes analysis and evaluation of mapped processes and events from the viewpoint of their impact upon people's health. Based on the events and processes imaged, a concise classification of maps used in hygiene is given.
Subject(s)
Maps as Topic , Public Health/methods , Bulgaria , Humans , Hygiene , Research DesignABSTRACT
"This paper reports an analysis of fertility in Bulgaria during the period 1960-1990. Alternative demographic indicators are used, such as period and cohort total fertility rates...[and] mean age [at] childbearing, marriage, and divorce. The analysis includes distribution by order of births. Two age patterns of fertility behaviour are distinguished, one for females aged below 22, and the other for females above that age. The report notes the different impact of pronatal policy actions undertaken in 1968 and in 1973...." (SUMMARY IN ENG AND RUS)
Subject(s)
Age Factors , Birth Rate , Divorce , Family Planning Policy , Fertility , Marriage , Maternal Age , Sexual Behavior , Bulgaria , Demography , Developed Countries , Europe , Europe, Eastern , Parents , Population , Population Characteristics , Population Dynamics , Public PolicyABSTRACT
PIP: The relevance of the multistate approach to the analysis of nuptiality is considered. Multistate life tables of marriage are constructed using official Bulgarian data for 1975. Four types of marital status are considered, namely, unmarried, married, divorced, and widowed. The probabilities of transition from one state to another and of length of duration in a given state are calculated. (summary in ENG, RUS)^ieng
Subject(s)
Divorce , Life Tables , Marital Status , Marriage , Methods , Probability , Single Person , Widowhood , Bulgaria , Demography , Developed Countries , Europe , Europe, Eastern , Research , Statistics as TopicABSTRACT
"Regional populations and their migrations are analysed as a system of populations. Such a system can be studied by multiregional models constructed on the basis of the multiregional approach. The results thus achieved may substantially differ from those received by the conventional approach. The theoretical formulations are illustrated by empirical studies of the rural and urban population of Bulgaria in 1960-1982." (summary in ENG, RUS)
