PubMed Health⌕ Search

Biomedical subjects

J Shanahan

Publications and source records attributed to J Shanahan.

6 recordsLinked to original sources
PubMed2006

Calculation of dose coefficients for radionuclides produced in a spallation neutron source utilizing NUBASE and the evaluated nuclear structure data file databases.

Based on a mercury spallation neutron source target, the UNLV Transmutation Research Program has identified 72 radionuclides with a half-life greater than or equal to a minute as lacking an appropriate reference for a published dose coefficient according to existing radiation safety dose coefficient databases. A method was developed to compare the nuclear data presented in the ENSDF and NUBASE databases for these 72 radionuclides. Due to conflicting or lacking nuclear data in one or more of the databases, internal and external dose coefficient values have been calculated for only 14 radionuclides, which are not currently presented in Federal Guidance Reports Nos. 11, 12, and 13 or Publications 68 and 72 of the International Commission on Radiological Protection. Internal dose coefficient values are reported for inhalation and ingestion of 1 microm and 5 microm AMAD particulates along with the f1 values and absorption types for the adult worker. Internal dose coefficient values are also reported for inhalation and ingestion of 1 microm AMAD particulates as well as the f1 values and absorption types for members of the public. Additionally, external dose coefficient values for air submersion, exposure to contaminated ground surface, and exposure to soil contaminated to an infinite depth are also presented.

Computer Simulation↗
PubMed2006

Quality assurance methods and procedures used to verify consistency in calculating dose coefficients.

The development of a spallation neutron source with a mercury target will lead to the production of rare radionuclides. The dose coefficients for many of these radionuclides have not yet been published. A collaboration of universities and national labs has taken on the task of calculating dose coefficients for the rare radionuclides using the software package DCAL. The working group developed a procedure for calculating dose coefficients and a quality assurance (QA) program to verify the calculations completed. The first portion of this QA program was to verify that each participating group could independently reproduce the dose coefficients for a known set of radionuclides. The second effort was to divide the group of rare radionuclides among the independent participants in a manner that assured that each radionuclide would be redundantly and independently calculated, and the results subsequently be submitted for publication in a separate manuscript. The final aspect of this program was to resolve any discrepancies arising among the participants as a group. The output of the various software programs for six QA radionuclides, 144Nd, 201Au, 50V, 61Co, 41Ar, and 38S were compared among all members of the working group. Initially, a few differences in outputs were identified. This exercise identified weaknesses in the procedure, which has since been revised. After the revisions, dose coefficients were calculated and compared to published dose coefficients with good agreement. The present efforts involve generating dose coefficients for the rare radionuclides anticipated to be produced from the spallation neutron source should a mercury target be employed.

Databases as Topic↗
PubMed1998

Alcohol portrayal on prime-time television: manifest and latent messages.

OBJECTIVE: The research in this article is designed to improve our understanding of alcohol messages embedded in prime-time television, especially when adolescent characters are shown portraying or consuming alcohol. METHOD: Manifest and latent content analyses are used to assess the frequency of alcohol portrayal in prime-time television and the personality traits (powerful, admirable, smart) of characters shown consuming or portraying alcohol on prime-time television. The sample includes 224 hours of programming across 276 programs on four major networks. RESULTS: Alcoholic beverages were the most frequently portrayed food or drink. The prominence of alcohol in prime-time television applies to all characters, including adolescents. The proportion of all food and drink incidents accounted for by alcohol equaled .14 for male and .20 for female adolescent television characters. Moreover, when adolescent characters are involved with alcohol incidents, they are more likely to be shown consuming this alcohol than are adults. A significant finding was that adolescents portraying alcohol in programming were shown to have significantly more negative personality characteristics than did characters in older age groups. CONCLUSIONS: Compared with other studies, this study finds higher rates of alcohol portrayal by adolescents on prime-time television. The negative character portrayal of adolescents involved with alcohol is encouraging. However, adult and high-income characters involved with alcohol, who might serve as role models for younger adults are, on average, shown with positive personality characteristics.

Adolescent↗
PubMed1994

Desert Shield deployment and social problems on a U.S. Army combat support post.

We undertook a study of selected mental health-related services at a combat support post to determine if stress levels surrounding Operations Desert Shield/Desert Storm had an effect on the utilization of these services. Our measure was the problem rate formed by adding the visits to the alcohol and drug service and the social work service. The findings (not all of which reached statistical significance in our small study) were that the problem rates were higher in those units which deployed, both before and after deployment. The pre-deployment differences in age, rank, and race between those soldiers deployed and not deployed is a finding which may help to account for the difference between units. There was a transient, but not sustained, problem rate increase immediately following return home for those units which deployed. Implications for mental health-related services staffing and directions for further research are discussed.

Adult↗