ORCID Profile
0000-0001-5678-9002
Current Organisation
Northumbria University
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Publisher: Springer Science and Business Media LLC
Date: 06-2023
DOI: 10.1007/S11207-023-02170-1
Abstract: The middle corona, the region roughly spanning heliocentric distances from 1.5 to 6 solar radii, encompasses almost all of the influential physical transitions and processes that govern the behavior of coronal outflow into the heliosphere. The solar wind, eruptions, and flows pass through the region, and they are shaped by it. Importantly, the region also modulates inflow from above that can drive dynamic changes at lower heights in the inner corona. Consequently, the middle corona is essential for comprehensively connecting the corona to the heliosphere and for developing corresponding global models. Nonetheless, because it is challenging to observe, the region has been poorly studied by both major solar remote-sensing and in-situ missions and instruments, extending back to the Solar and Heliospheric Observatory (SOHO) era. Thanks to recent advances in instrumentation, observational processing techniques, and a realization of the importance of the region, interest in the middle corona has increased. Although the region cannot be intrinsically separated from other regions of the solar atmosphere, there has emerged a need to define the region in terms of its location and extension in the solar atmosphere, its composition, the physical transitions that it covers, and the underlying physics believed to shape the region. This article aims to define the middle corona, its physical characteristics, and give an overview of the processes that occur there.
Publisher: Oxford University Press (OUP)
Date: 04-2017
Publisher: American Astronomical Society
Date: 10-04-2013
Publisher: American Astronomical Society
Date: 31-07-2023
Publisher: Springer Science and Business Media LLC
Date: 19-02-2021
DOI: 10.1038/S41467-021-21479-8
Abstract: Protein metal-occupancy (metalation) in vivo has been elusive. To address this challenge, the available free energies of metals have recently been determined from the responses of metal sensors. Here, we use these free energy values to develop a metalation-calculator which accounts for inter-metal competition and changing metal-availabilities inside cells. We use the calculator to understand the function and mechanism of GTPase CobW, a predicted Co II -chaperone for vitamin B 12 . Upon binding nucleotide (GTP) and Mg II , CobW assembles a high-affinity site that can obtain Co II or Zn II from the intracellular milieu. In idealised cells with sensors at the mid-points of their responses, competition within the cytosol enables Co II to outcompete Zn II for binding CobW. Thus, Co II is the cognate metal. However, after growth in different [Co II ], Co II -occupancy ranges from 10 to 97% which matches CobW-dependent B 12 synthesis. The calculator also reveals that related GTPases with comparable Zn II affinities to CobW, preferentially acquire Zn II due to their relatively weaker Co II affinities. The calculator is made available here for use with other proteins.
Publisher: American Astronomical Society
Date: 31-07-2023
Publisher: American Astronomical Society
Date: 07-2022
Abstract: The outer atmosphere of the Sun is composed of plasma heated to temperatures well in excess of the visible surface. We investigate short cool and warm ( MK) loops seen in the core of an active region to address the role of field-line braiding in energizing these structures. We report observations from the High-resolution Coronal imager (Hi-C) that have been acquired in a coordinated c aign with the Interface Region Imaging Spectrograph (IRIS). In the core of the active region, the 172 Å band of Hi-C and the 1400 Å channel of IRIS show plasma loops at different temperatures that run in parallel. There is a small but detectable spatial offset of less than 1″ between the loops seen in the two bands. Most importantly, we do not see observational signatures that these loops might be twisted around each other. Considering the scenario of magnetic braiding, our observations of parallel loops imply that the stresses put into the magnetic field have to relax while the braiding is applied: the magnetic field never reaches a highly braided state on these length scales comparable to the separation of the loops. This supports recent numerical 3D models of loop braiding in which the effective dissipation is sufficiently large that it keeps the magnetic field from getting highly twisted within a loop.
Location: United Kingdom of Great Britain and Northern Ireland
Location: United Kingdom of Great Britain and Northern Ireland
No related grants have been discovered for Richard Morton.