Birds appear to be equipped with an innate magnetic compass. One biophysical model of this sense relies on spin dynamics in photo-generated radical pairs in the protein cryptochrome. This study employs a systematic approach to predict the dependence of the compass sensitivity on the relative orientation of the constituent radicals for spin systems comprising up to 21 hyperfine interactions. Evaluating measures of compass sensitivity (anisotropy) and precision (optimality) derived from the singlet yield, we find the ideal relative orientations for the radical pairs consisting of the flavin anion (F •-) coupled with a tryptophan cation (W •+) or tyrosine radical (Y •). For the geomagnetic field, the two measures are found to be anti-correlated in [F •-W •+ ]. The angle spanned by the normals to the aromatic planes of the radicals is the decisive parameter determining the compass sensitivity. The third tryptophan of the tryptophan triad/tetrad, which has been implicated with magnetosensitive responses, exhibits a comparably large anisotropy, but unfavorable optimality. Its anisotropy could be boosted by an additional ~50 % by optimizing the relative orientation of the radicals. For a coherent lifetime of 1 μs, the maximal relative anisotropy of [F •-W •+ ] is 0.27 %. [F •-Y • ] radical pairs outperform [F •-W •+ ] for most relative orientations. Furthermore, anisotropy and optimality can be simultaneously maximized. The entanglement decays rapidly, implicating it as a situational byproduct rather than a fundamental driver within the avian compass. In magnetic fields of higher intensity, the relative orientation of radicals in [F •-W •+ ] is less important than for the geomagnetic field.
Abstract. The fusion of drone and wind lidar technology introduces the exciting possibility of performing high-quality wind measurements virtually anywhere. We present a proof-of-concept (POC) drone–lidar system and report results from several test campaigns that demonstrate its ability to measure accurate wind speeds. The POC system is based on a dual-telescope continuous-wave (CW) lidar, with drone-borne telescopes and ground-based optoelectronics. Commercially available drone and gimbal units are employed. The demonstration campaigns started with a series of comparisons of the wind speed measurements acquired by the POC system to simultaneous measurements performed by nearby mast-based sensors. On average, an agreement down to about 0.1 m s−1 between mast- and drone-based measurements of the horizontal wind speed is found. Subsequently, the extent of the flow disturbance caused by the drone downwash was investigated. These tests vindicated the somewhat conservative choice of lidar measurement ranges made for the initial wind speed comparisons. Overall, the excellent results obtained without any drone motion correction and with fairly primitive drone position control indicate the potential of drone–lidar systems in terms of accuracy and applications. The next steps in the development are outlined and several potential applications are discussed.
Abstract. The fusion of drone and wind lidar technology introduces the exciting possibility of performing high-quality wind measurements virtually anywhere for substantially lower costs than established in-situ and remote sensing techniques. In this paper we will present a proof of concept (POC) drone-lidar system and report results from several test campaigns that demonstrate its ability to measure accurate wind speeds. The POC system is based on a dual-telescope Continuous Wave (CW) lidar, with drone-borne telescopes and ground-based opto-electronics. Commercially available drone and gimbal units are employed. The demonstration campaigns started with a series of comparisons of the wind speed measurements acquired by the POC system to simultaneous measurements performed by nearby mast based sensors. Generally very good agreement was found. Subsequently the extent of the flow disturbance caused by the drone downwash was investigated. These tests vindicated the somewhat conservative choice of lidar measurement range made for the initial wind speed comparisons. Overall, the excellent results obtained without any drone motion correction and with fairly primitive drone position control indicate the potential of drone-lidar systems in terms of accuracy and applications. The next steps in the development are outlined in the paper and several potential applications are discussed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.