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Abstract Metal‐halide perovskites are known for their strong and tunable luminescence. However, the synthesis of perovskite‐based particles with circularly polarized light emission (CPLE) remains challenging due to the complex interplay of metal‐ligand chemistries, crystallization patterns, and chirality transfer mechanisms. Achiral perovskites can be deposited on chiral “hedgehog” particles (CHIPs) with twisted spikes, producing chiroptically active materials with spectroscopic bands specific to the perovskite and chirality specific to the template CHIPs. Left‐ and right‐handed CPLE is engineered into complex particles comprised of a layer of perovskite deposited onto CHIPs coated with an intermediate silica layer. The spectral position of chiroptical bands, the optical asymmetryg‐factors, and single‐particle circularly polarized microscopy indicate that the observed CPLE is dominated by the post‐emission scattering from the twisted spikes of the parent particle. Templating luminescent nanofilms on CHIPs provides a simple pathway to a wide range of complex chiroptical materials; the dispersibility of the CHIPs in various solvents and the tunability of their chiral geometry enable their applications as single‐particle emitters with strong and controllable polarization rotation. 

Abstract Alpine treelines are expected to shift upward due to recent climate change. However, interpretation of changes in montane systems has been problematic because effects of climate change are frequently confounded with those of land use changes. The eastern Himalaya, particularly Langtang National Park, Central Nepal, has been relatively undisturbed for centuries and thus presents an opportunity for studying climate change impacts on alpine treeline uncontaminated by potential confounding factors.We studied two dominant species,Abies spectabilis (AS)andRhododendron campanulatum (RC), above and below the treeline on two mountains. We constructed 13 transects, each spanning up to 400 m in elevation, in which we recorded height and state (dead or alive) of all trees, as well as slope, aspect, canopy density, and measures of anthropogenic and animal disturbance.All size classes ofRCplants had lower mortality above treeline than below it, and youngRCplants (<2 m tall) were at higher density above treeline than below.ASshows little evidence of a position change from the historic treeline, with a sudden extreme drop in density above treeline compared to below. Recruitment, as measured by size–class distribution, was greater above treeline than below for both species butASis confined to ~25 m above treeline whereasRCis luxuriantly growing up to 200 m above treeline.Synthesis. Evidence suggests that the elevational limits ofRChave shifted upward both because (a) young plants above treeline benefited from facilitation of recruitment by surrounding vegetation, allowing upward expansion of recruitment, and (b) temperature amelioration to mature plants increased adult survival. We predict that the current pure stand ofRCgrowing above treeline will be colonized byASthat will, in turn, outshade and eventually relegateRCto be a minor component of the community, as is the current situation below the treeline.