36 research outputs found
Properties of odd nuclei and the impact of time-odd mean fields: A systematic Skyrme-Hartree-Fock analysis
We present a systematic analysis of the description of odd nuclei by the
Skyrme-Hartree-Fock approach augmented with pairing in BCS approximation and
blocking of the odd nucleon. Current and spin densities in the Skyrme
functional produce time-odd mean fields (TOMF) for odd nuclei. Their effect on
basic properties (binding energies, odd-even staggering, separation energies
and spectra) is investigated for the three Skyrme parameterizations SkI3, SLy6,
and SV-bas. About 1300 spherical and axially-deformed odd nuclei with 16 < Z <
92 are considered. The calculations demonstrate that the TOMF effect is
generally small, although not fully negligible. The influence of the Skyrme
parameterization and the consistency of the calculations are much more
important. With a proper choice of the parameterization, a good description of
binding energies and their differences is obtained, comparable to that for even
nuclei. The description of low-energy excitation spectra of odd nuclei is of
varying quality depending on the nucleus
Nuclear Reaction Rates and Primordial Li
We examine the possibility that Big Bang Nucleosynthesis (BBN) may produce
non-trivial amounts of Li. If a primordial component of this isotope could
be observed, it would provide a new fundamental test of Big-Bang cosmology, as
well as new constraints on the baryon density of the universe. At present,
however, theoretical predictions of the primordial Li abundance are
extremely uncertain due to difficulties in both theoretical estimates and
experimental determinations of the deuterium-plus-alpha radiative capture
reaction cross-section. We also argue that present observational capabilities
do not yet allow the detection of primeval Li in very metal-poor stars of
the galactic halo. However, if the critical cross section is towards the upper
end of its plausible range, then improvements in Li detection capabilities
may allow the establishment of Li as another product of BBN. It is also
noted that a primordial Li detection could help resolve current concerns
about the extragalactic D/H determination.Comment: 10 pages, REVTeX, 5 PostScript figures with psfig. Submitted to
Physical Review
Neutron-induced nucleosynthesis
Neutron--induced nucleosynthesis plays an important role in astrophysical
scenarios like in primordial nucleosynthesis in the early universe, in the
s--process occurring in Red Giants, and in the --rich freeze--out and
r--process taking place in supernovae of type II. A review of the three
important aspects of neutron--induced nucleosynthesis is given: astrophysical
background, experimental methods and theoretical models for determining
reaction cross sections and reaction rates at thermonuclear energies. Three
specific examples of neutron capture at thermal and thermonuclear energies are
discussed in some detail.Comment: 40 pages (uses kluwer.sty), 2 postscript figures (uses psfig),
accepted for publication in Surveys in Geophysics, uuencoded tex-files and
postscript-files available at ftp://is1.kph.tuwien.ac.at/pub/ohu/Geo.u
Ethische und rechtliche Aspekte im Umgang mit genetischen Zufallsbefunden – Herausforderungen und Lösungsansätze
Secondary use of health care data and left-over biosamples within the ‘Medical Informatics Initiative’ (MII): a quasi-randomized controlled evaluation of patient perceptions and preferences regarding the consent process
Background
Data collected during routine health care and ensuing analytical results bear the potential to provide valuable information to improve the overall health care of patients. However, little is known about how patients prefer to be informed about the possible usage of their routine data and/or biosamples for research purposes before reaching a consent decision. Specifically, we investigated the setting, the timing and the responsible staff for the information and consent process.
Methods
We performed a quasi-randomized controlled trial and compared the method by which patients were informed either in the patient admission area following patient admission by the same staff member (Group A) or in a separate room by another staff member (Group B). The consent decision was hypothetical in nature. Additionally, we evaluated if there was the need for additional time after the information session and before taking the consent decision. Data were collected during a structured interview based on questionnaires where participants reflected on the information and consent process they went through.
Results
Questionnaire data were obtained from 157 participants in Group A and 106 participants in Group B. Overall, participants in both groups were satisfied with their experienced process and with the way information was provided. They reported that their (hypothetical) consent decision was freely made. Approximately half of the interested participants in Group B did not show up in the separate room, while all interested participants in Group A could be informed about the secondary use of their routine data and left-over samples. No participants, except for one in Group B, wanted to take extra time for their consent decision. The hypothetical consent rate for both routine data and left-over samples was very high in both groups.
Conclusions
The willingness to support medical research by allowing the use of routine data and left-over samples seems to be widespread among patients. Information concerning this secondary data use may be given by trained administrative staff immediately following patient admission. Patients mainly prefer making a consent decision directly after information is provided and discussed. Furthermore, less patients are informed when the process is organized in a separate room
The generic Informed Consent Service gICS®: implementation and benefits of a modular consent software tool to master the challenge of electronic consent management in research
Background
Defining and protecting participants’ rights is the aim of several ethical codices and legal regulations. According to these regulations, the Informed Consent (IC) is an inevitable element of research with human subjects. In the era of “big data medicine”, aspects of IC become even more relevant since research becomes more complex rendering compliance with legal and ethical regulations increasingly difficult.
Methods
Based on literature research and practical experiences gathered by the Institute for Community Medicine (ICM), University Medicine Greifswald, requirements for digital consent management systems were identified.
Results
To address the requirements, the free-of-charge, open-source software “generic Informed Consent Service” (gICS®) was developed by ICM to provide a tool to facilitate and enhance usage of digital ICs for the international research community covering various scenarios. gICS facilitates IC management based on IC modularisation and supports various workflows within research, including (1) electronic depiction of paper-based consents and (2) fully electronic consents. Numerous projects applied gICS and documented over 336,000 ICs and 2400 withdrawals since 2014.
Discussion
Since the consent’s content is a prerequisite for securing participants’ rights, application of gICS is no guarantee for legal compliance. However, gICS supports fine-granular consents and accommodation of differentiated consent states, which can be directly exchanged between systems, allowing automated data processing.
Conclusion
gICS simplifies and supports sustained IC management as a major key to successfully conduct studies and build trust in research with human subjects. Therefore, interested researchers are invited to use gICS and provide feedback for further improvements