Studies of transition metal complexes involving pyrimidine and related bases

Imperial Users onl

Comparative Effectiveness of Step-up Therapies in Children with Asthma Prescribed Inhaled Corticosteroids : A Historical Cohort Study

This work was supported by the Respiratory Effectiveness Group. Acknowledgments We thank the Respiratory Effectiveness Group for funding this work, Annie Burden for assistance with statistics, and Simon Van Rysewyk and Lisa Law for assistance with medical writing.Peer reviewedPostprin

Beyond the Adaptationist Legacy: Updating Our Teaching to Include a Diversity of Evolutionary Mechanisms

A paradigm shift away from viewing evolution primarily in terms of adaptation - the adaptationist programme of Gould and Lewontin - began in evolutionary research more than 35 years ago, but that shift has yet to occur within evolutionary education research or within teaching standards. We review three instruments that can help education researchers and educators undertake this paradigm shift. The instruments assess how biology undergraduates understand three evolutionary processes other than natural selection: genetic drift, dominance relationships among allelic pairs, and evolutionary developmental biology (evo-devo). Testing with these instruments reveals that students often explain a diversity of evolutionary mechanisms incorrectly by invoking misconceptions about natural selection. We propose that increasing the emphasis on teaching evolutionary processes other than natural selection could result in a better understanding of natural selection and a better understanding of all evolutionary processes. Finally, we propose two strategies for accomplishing this goal, interleaving natural selection with other evolutionary processes and the development of bridging analogies to describe evolutionary concepts

Many Paths Toward Discovery: A Module for Teaching How Science Works

Improving students\u27 understanding of how science works requires explicit instruction. Here, we test the efficacy of a module based on two previously published activities (the Cube Puzzle and the case study Asteroids and Dinosaurs ) that teach how science works to college science majors. Students also use the How Science Works Flowchart from Understanding Science (http://undsci.berkeley. edu/) to reflect on these activities. To assess the efficacy of this module, we asked students to illustrate the process of science before and after the intervention. After the intervention, students\u27 diagrams were significantly more complex and nonlinear. Students also incorporated more social aspects of science, such as discussing results with colleagues. However, few of the pre- or postdiagrams mentioned the way science benefits society. We conclude that our intervention is an easy-to-implement strategy for improving some aspects of scientific literacy in college students

A re-interpretation of the Triangulum-Andromeda stellar clouds: a population of halo stars kicked out of the Galactic disk

The Triangulum-Andromeda stellar clouds (TriAnd1 and TriAnd2) are a pair of concentric ring- or shell-like over-densities at large $R$ ($\approx$ 30 kpc) and $Z$ ($\approx$ -10 kpc) in the Galactic halo that are thought to have been formed from the accretion and disruption of a satellite galaxy. This paper critically re-examines this formation scenario by comparing the number ratio of RR Lyrae to M giant stars associated with the TriAnd clouds with other structures in the Galaxy. The current data suggest a stellar population for these over-densities ($f_{\rm RR:MG} < 0.38$ at 95% confidence) quite unlike any of the known satellites of the Milky Way ($f_{\rm RR:MG} \approx 0.5$ for the very largest and $f_{\rm RR:MG} >>1$ for the smaller satellites) and more like the population of stars born in the much deeper potential well inhabited by the Galactic disk ($f_{\rm RR:MG} < 0.01$). N-body simulations of a Milky-Way-like galaxy perturbed by the impact of a dwarf galaxy demonstrate that, in the right circumstances, concentric rings propagating outwards from that Galactic disk can plausibly produce similar over-densities. These results provide dramatic support for the recent proposal by Xu et al. (2015) that, rather than stars accreted from other galaxies, the TriAnd clouds could represent stars kicked-out from our own disk. If so, these would be the first populations of disk stars to be found in the Galactic halo and a clear signature of the importance of this second formation mechanism for stellar halos more generally. Moreover, their existence at the very extremities of the disk places strong constraints on the nature of the interaction that formed them.Comment: 27 pages, 8 figures; published in MNRA