| 1 | Beyond direct neighbourhood effects:higher-order interactions improve modelling and predicting tree survival and growth显示文摘It is known that biotic interactions are the key to species coexistence and maintenance of species diversity.Traditional studies focus overwhelmingly on pairwise interactions between organisms,ignoring complex higher-order interactions(HOIs).In this study,we present a novel method of calculating individual-level HOIs for trees,and use this method to test the importance of size-and distance-dependent individual-level HOIs to tree performance in a 25-ha temperate forest dynamic plot.We found that full HOI-inclusive models improved our ability to model and predict the survival and growth of trees,providing empirical evidence that HOIs strongly influence tree performance in this temperate forest.Specifically,assessed HOIs mitigate the competitive direct effects of neighbours on survival and growth of focal trees.Our study lays a foundation for future investigations of the prevalence and relative importance of HOIs in global forests and their impact on species diversity. | Yuanzhi Li Margaret M.Mayfield Bin Wang Junli Xiao Kamil Krai David Janik Jan Holik Chengjin Chu | 2021 | National Science Review2021，8，5： | 2 |
| 2 | The search for roAp stars: null results and new candidates from Strmgren-Crawford photometry显示文摘The rapidly oscillating Ap(roAp) stars exhibit pulsational photometric and/or radial velocity variations on time scales of several minutes, which are essential to test current pulsation models as well as our assumptions of atmospheric structure characteristics. In addition, their chemical peculiarity makes them very interesting for probing stellar formation and evolution in the presence of a global magnetic field. To date, a limited number of only 61 roAp stars is known to show photometric variability. On the other hand, a literature survey yields 619 unique stars that have unsuccessfully been searched for variability of this kind. Str o¨mgren-Crawford uvbyβ photometry of stars from both subgroups was used to investigate whether there is a selection bias for the investigated stars. We also present new photometric measurements(202 hours on 59 different nights) of 55 roAp candidates. We did not detect any new roAp star. Although our detection limits are comparable to other surveys, we also did not find pulsations in the known roAp star HD 12098, which may be a consequence of temporal amplitude changes. On the other hand, we do find some evidence for photometric variability of beta CrB at its spectroscopically derived pulsation period. From the uvbyβ photometry we conclude that the blue border of the roAp instability strip appears observationally well defined, whereas the red border is rather poorly known and studied.Within these boundaries, a total of 4646 candidates were identified which appear worth investigating for short-term pulsational variability. | Ernst Paunzen Gerald Handler Katerina Honkova Jakub Jurysek Martin Masek Marek Drozdz Jan Janik Waldemar Ogtoza Lars Hermansson Mats Johansson Martin Jelinek Marek Skarka Miloslav Zejda | 2018 | Research in Astronomy and Astrophysics2018，18，11： | 0 |
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