Article

Chemical-Shuttling Bacteria Follow Earth’s Magnetic Field

December 2020
Eos Transactions American Geophysical Union 101

DOI:10.1029/2020EO152294

Authors:

Magnetotactic bacteria shunt sulfur, nitrogen, and other important elements between oxygen-poor and oxygen-rich waters.

Were protocells basic abiogenic ancestral magnetosomes that evolved through natural selection into more complex life?

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Mar 2021

Andrew Planet

Magnetoreception is not restricted to prokaryotic bacteria but also occurs in eukaryotic organisms including fish and mammals, intimating that it developed at an early stage in the evolution of all living things.3 Speculating on the earliest of geological times, what if magnetism not only evolved in some universal common ancestor (LUCA) but was itself the only reason the very first protocells formed, transmuting through natural selection from the abiotic to life?1 This piece explores the possibility that magnetism is crucial for the self-organization of abiotic protocells into living matter.

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A Strong-flare Prediction Model Developed Using a Machine-learning Algorithm Based on the Video Data...

December 2023 · The Astrophysical Journal Supplement Series

It is well accepted that the physical properties obtained from the solar magnetic field observations of active regions (ARs) are related to solar eruptions. These properties consist of temporal features that might reflect the evolution process of ARs, and spatial features that might reflect the graphic properties of ARs. In this study, we generated video data sets with timescales of 1 day and ... [Show full abstract] image data sets of the SHARP radial magnetic field of the ARs from 2010 May to 2020 December. For the ARs that evolved from “quiet” to “active” and erupted the first strong flares in 4 days, we extract and investigate both the temporal and spatial features of ARs from videos, aiming to capture the evolution properties of their magnetic field structures during their transition process from “quiet” (non–strong flaring) to “active” (strong flaring). We then conduct a comparative analysis of the model performance by video input and single-image input, as well as of the effect of the model performance variation with the prediction window up to 3 days. We find that for those ARs that erupted the first strong flares in 4 days, the temporal features that reflect their evolution from “quiet” to “active” before the first strong flares can be recognized and extracted from the video data sets by our network. These features turn out to be important predictors that can effectively improve strong-flare prediction, especially by reducing the false alarms in a nearly 2 day prediction window.

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Estimating the Inertia Tensor Components of an Asymmetrical Spacecraft When Removing It from the Ope...

December 2023 · Sensors

The paper presents a method for estimating the inertia tensor components of a spacecraft that has expired its active life using measurement data of the Earth’s magnetic field induction vector components. The implementation of this estimation method is supposed to be carried out when cleaning up space debris in the form of a clapped-out spacecraft with the help of a space tug. It is assumed that a ... [Show full abstract] three-component magnetometer and a transmitting device are attached on space debris. The parameters for the rotational motion of space debris are estimated using this measuring system. Then, the known controlled action from the space tug is transferred to the space debris. Next, measurements for the rotational motion parameters are carried out once again. Based on the available measurement data and parameters of the controlled action, the space debris inertia tensor components are estimated. It is assumed that the measurements of the Earth’s magnetic field induction vector components are made in a coordinate system whose axes are parallel to the corresponding axes of the main body axis system. Such an estimation makes it possible to effectively solve the problem of cleaning up space debris by calculating the costs of the space tug working body and the parameters of the space debris removal orbit. Examples of numerical simulation using the measurement data of the Earth’s magnetic field induction vector components on the Aist-2D small spacecraft are given. Thus, the purpose of this work is to evaluate the components of the space debris inertia tensor through measurements of the Earth’s magnetic field taken using magnetometer sensors. The results of the work can be used in the development and implementation of missions to clean up space debris in the form of clapped-out spacecraft.

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What is the Effect of a Magnetic Field on Dye Adsorption onto Graphite Carbon?

December 2023 · Malaysian Journal of Fundamental and Applied Sciences

This research explores the impact of magnetic fields on dye adsorption onto graphite carbon, utilizing electric currents to generate varying magnetic field strengths, as determined by the Biot-Savart law. The study demonstrates that even with small current magnitudes typically used in physics laboratories, the generated magnetic fields significantly influence dye adsorption. Through experiments ... [Show full abstract] with currents ranging from 1.5 A to 7.5 A, resulting in magnetic fields from 1.54 µT to 4.63 µT, we observed enhanced adsorption for congo red, methylene blue, and methyl orange. In contrast, phenol red exhibited a unique desorption pattern due to electrostatic repulsion. Temperature variations were noted but were considered to have a negligible effect on the adsorption behavior. The findings highlight the crucial role of magnetic energy density and the charge of dye molecules in the adsorption process, leading to the conclusion that magnetic fields, indeed, play a significant role in influencing dye adsorption onto graphite carbon, with potential applications in environmental conservation and industrial waste management.

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Enhancement of electronic and magnetic properties in Cr2O3 monolayer honeycomb-kagome by hydrogenati...

December 2023 · The European Physical Journal Plus

This study investigates the structural, electronic, and magnetic properties of pristine, hydrogenated, and oxygenated Cr 2 O 3 monolayer honeycomb-kagome (HK) surface using first-principles calculations based on density functional theory (DFT). Molecular dynamics and phonon dispersion calculations demonstrate the thermal and dynamic stability of these systems, implying their feasibility for ... [Show full abstract] laboratory synthesis. The results revealed that the adsorption of hydrogen and oxygen atoms on the Cr 2 O 3 monolayer surface exhibited negative adsorption energies, indicating that these structures are energetically favorable. Specifically, the adsorption of oxygen atoms transforms the initial half-metallic nature of the monolayer into semiconducting behavior. Moreover, the introduction of hydrogen and oxygen atoms considerably enhances the Curie temperature of the surface. These findings offer a practical approach for enhancing the electronic and magnetic properties of Cr 2 O 3 monolayer HK surface, thereby facilitating their prospective application in spintronics.