Managing for change: October 11, 1989

Bi-weekly newsletter of University Hospital's Change Project, provided to managers at the hospital

Closing yield gaps in oil palm production systems in Ghana through Best Management Practices

The area under oil palm in Ghana has expanded but average fruit bunch yields remained low, resulting in large yield gaps. This study assessed the potential for increasing yield with 'Best Management Practices (BMP)' on plantations and smallholder farms in southern Ghana, compared with current standard practices, i.e. reference (REF) yield. We evaluated short-term (≤1 year) yield increases with 'yield taking' (improved crop recovery), and long-term increases (>1 year) with 'yield making' (better agronomy) practices and identified the factors that contributed most to yield improvements. Average fruit bunch yield increases with BMP were 2.1 t ha−1 (+19%) and 4.7 t ha−1 (+89%) with yield taking and 4.7 t ha−1 (+36%) and 7.6 t ha−1 (+76%) with yield making at plantations and smallholder farms respectively. Short-term yield improvements were achieved with more frequent harvesting events and improved field access, which can help finance inputs needed for the yield making phase. Our analysis suggests more balanced palm nutrition could contribute considerably to yield making, particularly on smallholder farms. Improved fertilizer recommendations are therefore essential for sustainable oil palm production in Ghana. Increasing yields to 21.0 t ha−1 on land already planted to oil palm, can increase national fruit bunch production from 2.5 Mt to 6.9 Mt, sparing 600,000 ha of land. However, labour constraints on plantations and lack of access to credit and agricultural inputs on smallholder farms are major hurdles that need to be overcome to increase production.</p

A litmus test for classifying recognition mechanisms of transiently binding proteins

Partner recognition in protein binding is critical for all biological functions, and yet, delineating its mechanism is challenging, especially when recognition happens within microseconds. We present a theoretical and experimental framework based on straight-forward nuclear magnetic resonance relaxation dispersion measurements to investigate protein binding mechanisms on sub-millisecond timescales, which are beyond the reach of standard rapid-mixing experiments. This framework predicts that conformational selection prevails on ubiquitin’s paradigmatic interaction with an SH3 (Src-homology 3) domain. By contrast, the SH3 domain recognizes ubiquitin in a two-state binding process. Subsequent molecular dynamics simulations and Markov state modeling reveal that the ubiquitin conformation selected for binding exhibits a characteristically extended C-terminus. Our framework is robust and expandable for implementation in other binding scenarios with the potential to show that conformational selection might be the design principle of the hubs in protein interaction networks

Measurement of the Ds lifetime

We report precise measurement of the Ds meson lifetime. The data were taken by the SELEX experiment (E781) spectrometer using 600 GeV/c Sigma-, pi- and p beams. The measurement has been done using 918 reconstructed Ds. The lifetime of the Ds is measured to be 472.5 +- 17.2 +- 6.6 fs, using K*(892)0K+- and phi pi+- decay modes. The lifetime ratio of Ds to D0 is 1.145+-0.049.Comment: 5 pages, 2 figures submitted to Phys. Lett.