Engineering properties of low to medium overconsolidation ratio offshore clays

This paper presents a summary of the geotechnical engineering properties of low to medium overconsolidation ratio offshore inorganic clays derived from a high quality database. These properties, such as preconsolidation stress and undrained shear strength, are required for design of most offshore infrastructure and for assessment of offshore geohazards. The database was developed through a series of Joint Industry Projects using results from offshore site investigations performed worldwide. The key feature of the database is that it only contains results obtained using good to excellent quality samples that were tested using advanced laboratory procedures such as constant rate of strain consolidation and consolidated undrained triaxial and direct simple shear. A secondary objective of the paper was to examine common empirical correlations between index tests (e.g., water content, Atterberg limits) and soil design parameters using the new database. Such empirical correlations between simple and inexpensive index tests and more costly advanced laboratory tests can serve a valuable purpose in offshore infrastructure design. This is particularly the case for preliminary design at early stages of projects where little information is known about soil properties, for small projects with limited site characterization budgets, and international projects at locations where advanced laboratory tests performed to international standards are not available. The paper describes development of the database and presents summary results and plots for undrained shear strength, in situ stress state, and consolidation and flow parameters. Results from the empirical correlations investigated are presented and the paper concludes with recommendations on use of the data and correlations in practice. The recommendations are limited to clays of low to medium overconsolidation ratio and are not applicable to highly overconsolidated and desiccated clays. While the database primarily consists of offshore clays, the correlations presented should also be applicable to terrestrial clays.publishedVersio

Population prevalence and inheritance pattern of recurrent CNVs associated with neurodevelopmental disorders in 12,252 newborns and their parents

Recurrent copy number variations (CNVs) are common causes of neurodevelopmental disorders (NDDs) and associated with a range of psychiatric traits. These CNVs occur at defined genomic regions that are particularly prone to recurrent deletions and duplications and often exhibit variable expressivity and incomplete penetrance. Robust estimates of the population prevalence and inheritance pattern of recurrent CNVs associated with neurodevelopmental disorders (NDD CNVs) are lacking. Here we perform array-based CNV calling in 12,252 mother–father–child trios from the Norwegian Mother, Father, and Child Cohort Study (MoBa) and analyse the inheritance pattern of 26 recurrent NDD CNVs in 13 genomic regions. We estimate the total prevalence of recurrent NDD CNVs (duplications and deletions) in live-born children to 0.48% (95% C.I.: 0.37–0.62%), i.e., ~1 in 200 newborns has either a deletion or duplication in these NDDs associated regions. Approximately a third of the newborn recurrent NDD CNVs (34%, N = 20/59) are de novo variants. We provide prevalence estimates and inheritance information for each of the 26 NDD CNVs and find higher prevalence than previously reported for 1q21.1 deletions (~1:2000), 15q11.2 duplications (~1:4000), 15q13.3 microdeletions (~1:2500), 16p11.2 proximal microdeletions (~1:2000) and 17q12 deletions (~1:4000) and lower than previously reported prevalence for the 22q11.2 deletion (~1:12,000). In conclusion, our analysis of an unselected and representative population of newborns and their parents provides a clearer picture of the rate of recurrent microdeletions/duplications implicated in neurodevelopmental delay. These results will provide an important resource for genetic diagnostics and counseling