Compiled by Li Yan
In the latest issue of Science, dated March 22, 2024, Volume 383, Issue 6689:
Physics
Title: Stable Quantum-Correlated Many-Body States through Engineered Dissipation
Abstract: Using up to 49 superconducting qubits, we prepared low-energy states of the transverse-field Ising model through coupling to dissipative auxiliary qubits. In one dimension, we observed long-range quantum correlations and a ground-state fidelity of 0.86 for 18 qubits at the critical point. In two dimensions, we found mutual information that extends beyond nearest neighbors. Lastly, by coupling the system to auxiliaries emulating reservoirs with different chemical potentials, we explored transport in the quantum Heisenberg model. Our results establish engineered dissipation as a scalable alternative to unitary evolution for preparing entangled many-body states on noisy quantum processors.
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Chemistry
Title: Alcohol-Alcohol Cross-Coupling Enabled by SH2 Radical Sorting
Abstract: In an era of chemical synthesis that prioritizes reducing time to target and maximizing exploration of chemical space, harnessing these building blocks for carbon-carbon bond-forming reactions is a key goal in organic chemistry. In particular, leveraging a single activation mode to form a new C(sp3)–C(sp3) bond from two alcohol subunits would enable access to an extraordinary level of structural diversity. In this work, we report a nickel radical sorting–mediated cross-alcohol coupling wherein two alcohol fragments are deoxygenated and coupled in one reaction vessel, open to air.
Link: Read more Chiral Ground States of Ferroelectric Liquid Crystals
Abstract: We show that the fundamental state of a ferroelectric nematic confined to a flat surface, without any external alignment constraints, exhibits chirality, manifesting both left- and right-handed polarization twists. Despite the increase in elastic energy due to helicoidal deformations and defect walls separating domains of opposite handedness, the twists lead to a reduction in electrostatic energy, which weakens upon doping the material with ions. This research underscores how the polar orientation order of molecules can induce chirality in soft matter without chemically induced chiral centers.
Source: Link to the full article
Repeated Co-option of HMG-Box Genes for Sex Determination in Brown Algae and Animals
Abstract: In numerous eukaryotes, genetic sex determination diverges from XX/XY or ZW/ZZ systems, instead relying on a specialized region of the U (female) or V (male) sex chromosomes, an area scarcely investigated. Here, we establish that HMG-box genes serve as male-determining factors in brown algae, mirroring their role in animal sex determination. Across a billion years of evolution, these lineages have independently repurposed HMG box genes for male determination, illustrating evolution's propensity to recurrently employ the same genetic "toolkit" for similar tasks.
Source: Link to the full article Structure and Function of Arabidopsis ABC Transporter ABCB19 in Brassinosteroid Export
Abstract: In this study, we demonstrate that ABCB19, a member of the ATP-binding cassette (ABC) transporter superfamily, acts as a transporter for brassinosteroids. We present the structural characteristics of ABCB19 in both its substrate-unbound and brassinosteroid-bound states. Bioactive brassinosteroids significantly activate the ATP hydrolysis activity of ABCB19, and experimental assays confirm the transport of brassinosteroids by ABCB19. In Arabidopsis thaliana, both ABCB19 and its closely related homolog, ABCB1, positively regulate responses to brassinosteroids. Our findings elucidate the mechanism of transport for bioactive brassinosteroids, closely coordinated with brassinosteroid signaling.
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Authors: Wei Ying, Yaowei Wang, et al.
Keywords: Arabidopsis, ABC transporter, ABCB19, brassinosteroids, export
Spillover Effects of Organic Agriculture on Pesticide Use on Nearby Fields
Abstract: Understanding the environmental impact of organic agriculture remains incomplete, and its potential spillover effects on pest populations or pest control activities in adjacent fields are still uncertain. Based on approximately 14,000 field observations annually from 2013 to 2019 in Kern County, California, we found that organic crop producers benefit from a reduction in overall pesticide use, particularly insecticide use, in the vicinity of organic fields. Conversely, conventional fields tend to increase pesticide application as the proportion of neighboring organic fields grows. Our simulation experiments indicate that clustering organic croplands spatially can effectively mitigate spillover effects that lead to a net increase in pesticide use.
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Authors: Ashley E. Larsen, Frederik Noack, and L. Claire Powers
Keywords: organic agriculture, pesticide use, spillover effects, pest control, Kern County
