46 research outputs found
Pinning down electron correlations in RaF via spectroscopy of excited states
We report the spectroscopy of 11 electronic states in the radioactive
molecule radium monofluoride (RaF). The observed excitation energies are
compared with state-of-the-art relativistic Fock-space coupled cluster (FS-RCC)
calculations, which achieve an agreement of >99.71% (within ~8 meV) for all
states. High-order electron correlation and quantum electrodynamics corrections
are found to be important at all energies. Establishing the accuracy of
calculations is an important step towards high-precision studies of these
molecules, which are proposed for sensitive searches of physics beyond the
Standard Model.Comment: Submitted for publicatio
Improving the use of crop models for risk assessment and climate change adaptation
Crop models are used for an increasingly broad range of applications, with a commensurate proliferation of methods. Careful framing of research questions and development of targeted and appropriate methods are therefore increasingly important. In conjunction with the other authors in this special issue, we have developed a set of criteria for use of crop models in assessments of impacts, adaptation and risk. Our analysis drew on the other papers in this special issue, and on our experience in the UK Climate Change Risk Assessment 2017 and the MACSUR, AgMIP and ISIMIP projects. The criteria were used to assess how improvements could be made to the framing of climate change risks, and to outline the good practice and new developments that are needed to improve risk assessment. Key areas of good practice include: i. the development, running and documentation of crop models, with attention given to issues of spatial scale and complexity; ii. the methods used to form crop-climate ensembles, which can be based on model skill and/or spread; iii. the methods used to assess adaptation, which need broadening to account for technological development and to reflect the full range options available. The analysis highlights the limitations of focussing only on projections of future impacts and adaptation options using pre-determined time slices. Whilst this long-standing approach may remain an essential component of risk assessments, we identify three further key components: 1. Working with stakeholders to identify the timing of risks. What are the key vulnerabilities of food systems and what does crop-climate modelling tell us about when those systems are at risk? 2. Use of multiple methods that critically assess the use of climate model output and avoid any presumption that analyses should begin and end with gridded output. 3. Increasing transparency and inter-comparability in risk assessments. Whilst studies frequently produce ranges that quantify uncertainty, the assumptions underlying these ranges are not always clear. We suggest that the contingency of results upon assumptions is made explicit via a common uncertainty reporting format; and/or that studies are assessed against a set of criteria, such as those presented in this paper
Spatial and temporal variability of urban soil water dynamics observed by a soil monitoring network
IUSS SUITMA 6 International Symposium 2011
Soils in urban, industrial, traffic, mining and military areas (SUITMA) is a working group of the International Union of Soil Sciences created in 1998 to increase and promote soil science in strongly anthropized areas (Morel and Heinrich 2008). Originally dedicated to basic soil science aimed at the description, analysis, classification, and mapping of soils developed in human-transformed environments, i.e., the SUITMAs, which exhibit contrasting features in comparison with natural soils, the SUITMA group interest has shifted towards the study of soil functions, their status and restoration, and their role in the functioning and evolution of urban ecosystems