Frequently Asked Questions

Why, in some instances, are there so many different representations or views of the same data?
Ans:

     This is partially historical and based on real, or perceived, needs of the user communities and partially due to the rapidly evolving technology of the Internet.
     Two primary examples of the former are:

• The representations of evaluated nuclear structure data trace their roots to the the Table of Isotopes, the Nuclear Data Sheets, and articles in Nuclear Physics. Some sites, such as the TUNL Nuclear Data Evaluation Group, attempt to present the information in several styles, while most continue to present it in their "traditional" way.
• For nuclear decay data, two formats ("Medical Listing" and "Medical Internal Radiation Dose") were developed in the early 1960's at Oak Ridge National Laboratory and have been used for many publications and some databases since then. Others have also been designed since then to meet the perceived needs of the user communities. Some groups, such as the National Nuclear Data Center (NNDC), attempt to present the data in several of the formats.

At this stage, each of the styles have developed a strong group of advocates, and detractors, and it is unlikely that the situation will improve in the near future. The best advice is to use the representation that is the most comfortable and useful to you.
     The technology on the Internet has been rapidly changing in the last few years allowing new and better ways of serving the information. This has lead to a great deal of experimentation among the various members of the USNDP and to different ways of viewing or obtaining the information (e.g., three different Q-value calculators). Over the next few years, members of the USNDP should be exchanging what they have learned and developing more coherent and consistent views.
(TWB. May 28, 1998)

How do I resolve discrepancies in information retrieved from different sites?
Ans:

     In principle the information you retrieve should be traceable (i.e., where it came from and when it was obtained) and any changes to the original data clearly documented. This has not always be done in a consistent or obvious matter in the past but should improve in the near future.
     One of the major reasons for discrepancies is age. For example, many questions have been received on why data obtained through the MIRD page at the NNDC differ from those published in ICRP-38. In most instances, the answer was that ICRP-38 was based on the Evaluated Nuclear Structure Data File (ENSDF) as of 1978 or 1979 while MIRD retrievals are based on the current ENSDF. A current problem is that the databases at remote centers are not updated as frequently as at the main centers and this may result in different information. Members of the program are working on new methods to solve this.
     If you are unable to resolve the discrepancies based on the available documentation, please contact the persons responsible for the various sites. Note also that in the United States much of the data is derived from the master databases maintained by the National Nuclear Data Center and these may also be checked.
(TWB. May 28, 1998)

How do I cite the data retrieved over the Internet?
Ans:

     This a problem that publishers, data centers, and others are still trying to address. Members of the Nuclear Data Centers Network have produced Citation Guidelines for Nuclear Data Retrieved from Databases Resident at Nuclear Data Centers Network which attempts to address the problem for several of the major databases. Several individual groups have also given examples on citing information obtained from their sites (e.g., http://www.tunl.duke.edu/nucldata/citation.html).
     Two of the major problems are that URL's often change and some of the major databases are updated on a weekly basis. At this stage, I would suggest that you cite the published version, if possible, and treat any data retrieved over the Internet as you would a private communication - keep a permanent copy of the data as retrieved.
(TWB. May 28, 1998)