49 research outputs found
How the composition of sandstone matrices affects rates of soil formation
Soils deliver multiple ecosystem services and their long-term sustainability is fundamentally controlled by the rates at which they form and erode. Our knowledge and understanding of soil formation is not commensurate with that of soil erosion, in part due to the difficulty of measuring the former. However, developments in cosmogenic radionuclide accumulation models have enabled soil scientists to more accurately constrain the rates at which soils form from bedrock. To date, all three major rock types â igneous, sedimentary and metamorphic lithologies â have been examined in such work. Soil formation rates have been measured and compared between these rock types, but the impact of rock characteristics on soil formation rates, such as rock matrices and mineralogy, have seldom been explored. In this UK-based study, we used cosmogenic radionuclide analysis to investigate whether the lithological variability of sandstone governs pedogenesis. Soil formation rates were measured on two arable hillslopes at Woburn and Hilton, which are underlain by different types of arenite sandstone. Rates were faster at Woburn, and we suggest that this is due to the fact that the Woburn sandstone formation is less cemented that that at Hilton. Similarly, rates at Woburn and Hilton were found to be faster than those measured at two other sandstone-based sites in the UK, and faster than those compiled in a global inventory of cosmogenic studies on sandstone-based soils. We suggest that the cementing agents present in matrix-abundant wackes studied previously may afford these sandstones greater structural integrity and resistance to weathering. This work points to the importance of factoring bedrock matrices into our understanding of soil formation rates, and the biogeochemical cycles these underpi
Soil loss by water erosion in areas under maize and jack beans intercropped and monocultures
Forests, water and land health are the natural capital of African montane forest ecosystems
Evaluating CHARGE syndrome in congenital hypogonadotropic hypogonadism patients harboring CHD7 variants.
Congenital hypogonadotropic hypogonadism (CHH), a rare genetic disease caused by gonadotropin-releasing hormone deficiency, can also be part of complex syndromes (e.g., CHARGE syndrome). CHD7 mutations were reported in 60% of patients with CHARGE syndrome, and in 6% of CHH patients. However, the definition of CHD7 mutations was variable, and the associated CHARGE signs in CHH were not systematically examined.
Rare sequencing variants (RSVs) in CHD7 were identified through exome sequencing in 116 CHH probands, and were interpreted according to American College of Medical Genetics and Genomics guidelines. Detailed phenotyping was performed in CHH probands who were positive for CHD7 RSVs, and genotype-phenotype correlations were evaluated.
Of the CHH probands, 16% (18/116) were found to harbor heterozygous CHD7 RSVs, and detailed phenotyping was performed in 17 of them. Of CHH patients with pathogenic or likely pathogenic CHD7 variants, 80% (4/5) were found to exhibit multiple CHARGE features, and 3 of these patients were reclassified as having CHARGE syndrome. In contrast, only 8% (1/12) of CHH patients with nonpathogenic CHD7 variants exhibited multiple CHARGE features (Pâ=â0.01).
Pathogenic or likely pathogenic CHD7 variants rarely cause isolated CHH. Therefore a detailed clinical investigation is indicated to clarify the diagnosis (CHH versus CHARGE) and to optimize clinical management
Bioelectric properties of cystic fibrosis airways obtained at heart-lung transplantation.
The significance of preschool behaviour problems for adjustment in later life
âA child is born into a world of phenomena all equal in their power to enslave. It sniffs, it sucks â it strokes its eyes over the whole uncomfortable range. Suddenly, one strikes. Why? Moments snap together like magnets, forging a chain of shackles. Why? I can trace them. I can even with time pull them apart again. But why at the start they were ever magnetized at all âjust those particular moments of experience and no others â I don't know. And nor does anyone else.â from Equus by Schaffer (1974). Quoted in Chess, S. and Thomas, A. (1984)Origins and Evolution of Behaviour Disorders: from infancy to early adult life. Brunner Mazel, NY. The discussion of the significance of preschool behaviour problems for later adjustment begins by grounding the issue in the wider theoretical framework of developmental psychology. Transactionalismis identified as a global theory which now governs our understanding of developmental processes. It is shown to have a powerful explanatory value in relation to the longâterm effects of early adjustment problems. Longitudinal studies are reviewed and the development, maintenance and conversion of early problems (or indeed their disappearance or moderation) can be identified as transactional processes. The concept of risk and resilience are of central importance; some individuals show âcompetenceâ and resist adversity but establishing why is beset with methodological and conceptual problems which may obscure actual vulnerability or misconstrue risk variables. Finally, research is found to be of limited value which does not address and explore the processes and mechanisms underlying resilience. A recent review of the impact of maternal depression on children exemplifies a transactional approach to understanding behavioural problems and also addresses the demand for a description of mechanisms involved. However, the issue of risk remains a major challenge