Ordered hierarchy versus scale invariance in sequence stratigraphy

200 x 10(6) years) are symmetrical transgressive- regressive cycles. However, the sequence record in the range of 1 x 10(4)-200 x 10(6) years, the principal domain of sequence stratigraphy, shows a rather irregular succession of sequences with variable symmetry and bounded by flooding surfaces or exposure surfaces. For these time scales, scale-invariant models are a good first approximation, particularly because the evidence for scale-invariance and randomness in the stratigraphic record is strong: Frequency spectra of sea-level change as well as rates of sedimentation and rates of accommodation change plotted against length of observation span show basic trends indistinguishable from random walk. These trends, combined with scale-invariant sequence models may be the most efficient tools for across-the-board predictions on sequences and for locating islands of order in the sequence record

'You want the right amount of oversight' : interviews with data access committee members and experts on genomic data access

Purpose: Genomic data sharing is vital for optimizing the use of public-funded research data. Data access committees (DACs) have been introduced as a core component of governance in controlled access models. However, the tasks, structure, and functionality of DACs often remain unstudied. This article investigates the role and adequacy of DACs in access reviews from the perspective of DAC members and experts. Methods: Twenty semi-structured interviews were conducted with both DAC members engaged in genomic data sharing via controlled-access databases and experts in the field. Results: The respondents indicated that protecting the privacy of data subjects along with recognition of data producers' efforts are the main underlying reasons of access review and the controlled-access model. In reviewing the ethical basis and the scientific aspects of access requests, tools and mechanisms such as consent forms, data access agreements, and guidelines have been used. Nevertheless, DAC members and experts identified shortcomings associated with current approaches that may adversely impact the effectiveness and efficiency of access review. Conclusion: The identified shortcomings of current approaches to access review could be addressed via complementary mechanisms and alternative models of data sharing to facilitate access to data sets in a responsible fashion