Tree-ring width wavelet and spectral analysis of solar variability and climatic effects on a Chilean cypress during the last two and a half millennia

International audienceSpectral and wavelet analysis were performed on a tree ring width time series obtained from a 2500 yr old cypress tree (Fitzroya cupressoides) from Costa del Osorno, Chile. The periods for analysis were selected at 95% confidence level. Both periodicities characteristic of solar activity and climatic variations were found in this tree ring width series. The 11 and 22 years solar cycle periods were present in tree ring data with a confidence level above 98%. This indicates the solar modulation of climatic variations is being recorded by the tree ring grown. However wavelet analysis shows that these are present only sparsely. Short-term variations, between 2-5 years, are also present in tree ring data, and are shown by wavelet maps to be a more permanent characteristic. This time scale is a signature of ENSO events. Long-term variations, above 200 years, are also present in tree ring data. The spectral analysis performed in this work shows that this species has the ability to record solar-ENSO variations that seems to be affecting the local environment of tree growth, and also that this region was influenced by ENSO events at least in the past 2500 yr interval covered by this study

Mild Pd-Catalyzed Aminocarbonylation of (Hetero)Aryl Bromides with a Palladacycle Precatalyst

A palladacyclic precatalyst is employed to cleanly generate a highly active XantPhos-ligated Pd-catalyst. Its use in low temperature aminocarbonylations of (hetero)aryl bromides provides access to a range of challenging products in good to excellent yields with low catalyst loading and only a slight excess of CO. Some products are unattainable by traditional carbonylative coupling.National Institutes of Health (U.S.) (Award GM46059)Danish National Research Foundation (Grant DNRF59)Villum FoundationDanish Council for Independent Researc

A sense of change: media designers and artists communicating about complexity in social-ecological systems

To take on the current and future challenges of global environmental change, fostering a widespread societal understanding of and engagement with the complex dynamics that characterize interacting human and natural systems is essential. Current science communication methods struggle with a number of specific challenges associated with communicating about complex systems. In this study we report on two collaborative processes, a short workshop and longer course, that aimed to harness the insights of interactive media designers and artists to overcome these challenges. The two processes resulted in 86 new interactive media concepts which were selected by the participants and organizers using set criteria and then evaluated using the same criteria by a panel of communication and media design experts and a panel of complex systems scientists using the same criteria. The top eight concepts are discussed in this paper. These concepts fell into the categories of serious games, group interaction concepts, and social media storytelling. The serious games focused directly on complex systems characteristics and were evaluated to be intuitive and engaging designs that combined transparency and complexity well. The group interaction concepts focused mostly on feedbacks and nonlinearity but were fully developed and tested in the workshops, and evaluated as engaging, accessible, and easy to implement in workshops and educational settings. The social media storytelling concepts involved less direct interactions with system dynamics but were seen as highly accessible to large scale audiences. The results of this study show the potential of interdisciplinary collaboration between complex systems scientists, designers, and artists. The results and process discussed in this paper show the value of more structural engagement of interactive media designers and artist communities in the development of communication tools about human and natural systems change