| 1. |
- Jorgensen, A. A., et al.
(författare)
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Petabit-per-second data transmission using a chip-scale microcomb ring resonator source
- 2022
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Ingår i: Nature Photonics. - : Springer Science and Business Media LLC. - 1749-4885 .- 1749-4893. ; 16:11, s. 798-802
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Tidskriftsartikel (refereegranskat)abstract
- Optical fibre communication is the backbone of the internet. As essential core technologies are approaching their limits of size, speed and energy-efficiency, there is a need for new technologies that offer further scaling of data transmission capacity. Here we show that a single optical frequency-comb source based on a silicon nitride ring resonator supports data capacities in the petabit-per-second regime. We experimentally demonstrate transmission of 1.84 Pbit s–1 over a 37-core, 7.9-km-long fibre using 223 wavelength channels derived from a single microcomb ring resonator producing a stabilized dark-pulse Kerr frequency comb. We also present a theoretical analysis that indicates that a single, chip-scale light source should be able to support 100 Pbit s–1 in massively parallel space-and-wavelength multiplexed data transmission systems. Our findings could mark a shift in the design of future communication systems, targeting device-efficient transmitters and receivers.
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| 2. |
- Kong, D., et al.
(författare)
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Single Dark-Pulse Kerr Comb Supporting 1.84 Pbit/s Transmission over 37-Core Fiber
- 2020
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Ingår i: Conference Proceedings - Lasers and Electro-Optics Society Annual Meeting-LEOS. - 1092-8081. ; 2020-May
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Konferensbidrag (refereegranskat)abstract
- We show that a single dark-pulse Kerr comb can generate high enough OSNR to carry 1.84 Pbit/s data, achieved by 223 WDM spectral lines modulated with 32-Gbaud, SNR-adapted probabilistically shaped DP-QAM, over a 37-core fiber.
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| 3. |
- von Oppen, J., et al.
(författare)
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Annual air temperature variability and biotic interactions explain tundra shrub species abundance
- 2021
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Ingår i: Journal of Vegetation Science. - : Wiley. - 1100-9233 .- 1654-1103. ; 32:2
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Tidskriftsartikel (refereegranskat)abstract
- Questions Shrub vegetation has been expanding across much of the rapidly changing Arctic. Yet, there is still uncertainty about the underlying drivers of shrub community composition. Here, we use extensive vegetation surveys and a trait-based approach to answer the following questions: which abiotic and biotic factors explain abundance of shrub species and functional groups in the Arctic tundra, and can we interpret these relationships using plant traits related to resource acquisition? Location Nuup Kangerlua (Godthabsfjord), western Greenland. Methods We tested the power of nine climatic, topographic and biotic variables to explain the abundances of nine shrub species using a Bayesian hierarchical modelling framework. Results We found highly variable responses among species and functional groups to both abiotic and biotic environmental variation. The overall most important abiotic explanatory variable was annual air temperature variability, which was highly correlated with winter minimum air temperature. Functional community composition and graminoid abundance were the most influential biotic factors. While we did not find systematic patterns between shrub abundances and abiotic variables with regard to resource acquisition traits, these traits did explain relationships between shrub abundances and biotic variables. Conclusions Shrub abundance responses to abiotic variables rarely aligned with expectations based on plants' resource acquisition traits or functional groups. Our results, therefore, indicate that approaches exclusively based on resource acquisition traits might be limited in their ability to predict abundances of individual groups and species, particularly in response to complex abiotic environments. However, integrating community theory and functional trait concepts represents a promising pathway to better predict biotic interactions and ultimately responses of dominant shrub vegetation to rapid environmental changes across the arctic tundra biome.
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| 4. |
- Sendker, Franziska L., et al.
(författare)
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Emergence of fractal geometries in the evolution of a metabolic enzyme
- 2024
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Ingår i: Nature. - : Springer Nature. - 0028-0836 .- 1476-4687. ; 628:8009, s. 894-900
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Tidskriftsartikel (refereegranskat)abstract
- Fractals are patterns that are self-similar across multiple length-scales1. Macroscopic fractals are common in nature2,3,4; however, so far, molecular assembly into fractals is restricted to synthetic systems5,6,7,8,9,10,11,12. Here we report the discovery of a natural protein, citrate synthase from the cyanobacterium Synechococcus elongatus, which self-assembles into Sierpiński triangles. Using cryo-electron microscopy, we reveal how the fractal assembles from a hexameric building block. Although different stimuli modulate the formation of fractal complexes and these complexes can regulate the enzymatic activity of citrate synthase in vitro, the fractal may not serve a physiological function in vivo. We use ancestral sequence reconstruction to retrace how the citrate synthase fractal evolved from non-fractal precursors, and the results suggest it may have emerged as a harmless evolutionary accident. Our findings expand the space of possible protein complexes and demonstrate that intricate and regulatable assemblies can evolve in a single substitution.
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