8 results on '"Fleming, Andrew"'
Search Results
2. Using telemetry data and the sea ice satellite record to identify vulnerabilities in critical moult habitat for emperor penguins in West Antarctica.
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Trathan, Philip N., Wienecke, Barbara, Fleming, Andrew, and Ireland, Louise
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MOLTING , *PENGUINS , *TELEMETRY , *SEA ice drift , *POLYNYAS , *TERRITORIAL waters , *SEA ice - Abstract
We tracked adult emperor penguins from Rothschild Island, west Antarctic Peninsula in 2015/2016 during a summer with extensive sea ice of long duration, contrasting with past years of reduced sea ice extent associated with the recent, rapid, warming trend across the region. We fitted ARGOS PTT devices to penguins of unknown breeding status. Of 33 penguins tracked, nine returned to the colony, presumably to provision offspring. Their foraging trips lasted 9.6 ± 3.7 days, with maximum distances of 75 ± 45 km from the colony within coastal waters. Also, 18 instruments transmitted until the initiation of the annual moult. Penguins travelled at ~ 2.3 km h−1 before slowing for moult. Post-moult, some devices continued to transmit, with speeds of ~ 0.8 km h−1, plausibly due to ice drift, which is rapid in this region. Penguins remained within the seasonal sea ice throughout, staying within 100 km of land, and generally within 5 to 10 km of features (open water, polynyas, leads, icebergs) that offered potential access to the ocean. Penguins were unlikely to have been constrained by the extensive sea ice habitat in 2015/2016. Similar habitats would also have been available in most years of the satellite record (since 1979); however, the moult locations in 2015/2016 would not have been available in many years, and penguins would have needed to find alternative moult locations during some years. Despite uncertainties, the moult period is a critical time for emperor penguins, particularly as sea ice declines, potentially affecting adult survival. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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3. Sea ice detection using concurrent multispectral and synthetic aperture radar imagery.
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Rogers, Martin S.J., Fox, Maria, Fleming, Andrew, van Zeeland, Louisa, Wilkinson, Jeremy, and Hosking, J. Scott
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Synthetic Aperture Radar (SAR) imagery is the primary data type used for sea ice mapping due to its spatiotemporal coverage and the ability to detect sea ice independent of cloud and lighting conditions. Automatic sea ice detection using SAR imagery remains problematic due to the presence of ambiguous signal and noise within the image. Conversely, ice and water are easily distinguishable using multispectral imagery (MSI), but in the polar regions the ocean's surface is often occluded by cloud or the sun may not appear above the horizon for many months. To address some of these limitations, this paper proposes a new tool trained using concurrent multispectral Visible and SAR imagery for sea Ice Detection (ViSual_IceD). ViSual_IceD is a convolution neural network (CNN) that builds on the classic U-Net architecture by containing two parallel encoder stages, enabling the fusion and concatenation of MSI and SAR imagery containing different spatial resolutions. The performance of ViSual_IceD is compared with U-Net models trained using concatenated MSI and SAR imagery as well as models trained exclusively on MSI or SAR imagery. ViSual_IceD outperforms the other networks, with a F1 score 1.30% points higher than the next best network, and results indicate that ViSual_IceD is selective in the image type it uses during image segmentation. Outputs from ViSual_IceD are compared to sea ice concentration products derived from the AMSR2 Passive Microwave (PMW) sensor. Results highlight how ViSual_IceD is a useful tool to use in conjunction with PMW data, particularly in coastal regions. As the spatial-temporal coverage of MSI and SAR imagery continues to increase, ViSual_IceD provides a new opportunity for robust, accurate sea ice coverage detection in polar regions. • ViSual_IceD is a convolutional neural network (CNN) trained for sea ice detection. • The CNN inputs multispectral and radar images outperforming single image tools. • The network selects the most informative image type during segmentation. • Network outputs are more accurate than coastal AMSR2 sea ice concentration data. [ABSTRACT FROM AUTHOR]
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- 2024
- Full Text
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4. Feasibility of gold nanocones for collocated tip-enhanced Raman spectroscopy and atomic force microscope imaging.
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McCourt, Luke R., Routley, Ben S., Ruppert, Michael G., and Fleming, Andrew J.
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ATOMIC spectroscopy , *RAMAN spectroscopy , *TOPOGRAPHIC maps , *CARBON nanotubes , *METAL coating , *GOLD , *SINGLE walled carbon nanotubes - Abstract
Microcantilever probes for tip-enhanced Raman spectroscopy (TERS) have a grainy metal coating that may exhibit multiple plasmon hotspots near the tip apex, which may compromise spatial resolution and introduce imaging artefacts. It is also possible that the optical hotspot may not occur at the mechanical apex, which introduces an offset between TERS and atomic force microscope maps. In this article, a gold nanocone TERS probe is designed and fabricated for 638 nm excitation. The imaging performance is compared to grainy probes by analysing high-resolution TERS cross-sections of single-walled carbon nanotubes. Compared to the tested conventional TERS probes, the nanocone probe exhibited a narrow spot diameter, comparable optical contrast, artefact-free images, and collocation of TERS and atomic force microscope topographic maps. The 1/e² spot diameter was 12.5 nm and 19 nm with 638 nm and 785 nm excitation, respectively. These results were acquired using a single gold nanocone probe to experimentally confirm feasibility. Future work will include automating the fabrication process and statistical analysis of many probes. [ABSTRACT FROM AUTHOR]
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- 2024
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5. Synthesis and import of GDP‐l‐fucose into the Golgi affect plant–water relations.
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Waszczak, Cezary, Yarmolinsky, Dmitry, Leal Gavarrón, Marina, Vahisalu, Triin, Sierla, Maija, Zamora, Olena, Carter, Ross, Puukko, Tuomas, Sipari, Nina, Lamminmäki, Airi, Durner, Jörg, Ernst, Dieter, Winkler, J. Barbro, Paulin, Lars, Auvinen, Petri, Fleming, Andrew J., Andersson, Mats X., Kollist, Hannes, and Kangasjärvi, Jaakko
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GOLGI apparatus , *FUCOSE , *FUCOSYLATION , *ARABIDOPSIS thaliana , *IMPORTS , *WATER efficiency - Abstract
Summary: Land plants evolved multiple adaptations to restrict transpiration. However, the underlying molecular mechanisms are not sufficiently understood.We used an ozone‐sensitivity forward genetics approach to identify Arabidopsis thaliana mutants impaired in gas exchange regulation.High water loss from detached leaves and impaired decrease of leaf conductance in response to multiple stomata‐closing stimuli were identified in a mutant of MURUS1 (MUR1), an enzyme required for GDP‐l‐fucose biosynthesis. High water loss observed in mur1 was independent from stomatal movements and instead could be linked to metabolic defects. Plants defective in import of GDP‐l‐Fuc into the Golgi apparatus phenocopied the high water loss of mur1 mutants, linking this phenotype to Golgi‐localized fucosylation events. However, impaired fucosylation of xyloglucan, N‐linked glycans, and arabinogalactan proteins did not explain the aberrant water loss of mur1 mutants.Partial reversion of mur1 water loss phenotype by borate supplementation and high water loss observed in boron uptake mutants link mur1 gas exchange phenotypes to pleiotropic consequences of l‐fucose and boron deficiency, which in turn affect mechanical and morphological properties of stomatal complexes and whole‐plant physiology. Our work emphasizes the impact of fucose metabolism and boron uptake on plant–water relations. [ABSTRACT FROM AUTHOR]
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- 2024
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6. Pathogenic Variant Frequencies in Hereditary Haemorrhagic Telangiectasia Support Clinical Evidence of Protection from Myocardial Infarction.
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Jain, Kinshuk, McCarley, Sarah C., Mukhtar, Ghazel, Ferlin, Anna, Fleming, Andrew, Morris-Rosendahl, Deborah J., and Shovlin, Claire L.
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MYOCARDIAL infarction , *HEREDITARY hemorrhagic telangiectasia , *TELANGIECTASIA , *GENETIC variation , *MISSENSE mutation , *GENETIC testing - Abstract
Hereditary haemorrhagic telangiectasia (HHT) is a vascular dysplasia inherited as an autosomal dominant trait, due to a single heterozygous loss-of-function variant, usually in ACVRL1 (encoding activin receptor-like kinase 1 [ALK1]), ENG (encoding endoglin [CD105]), or SMAD4. In a consecutive single-centre series of 37 positive clinical genetic tests performed in 2021–2023, a skewed distribution pattern was noted, with 30 of 32 variants reported only once, but ACVRL1 c.1231C>T (p.Arg411Trp) identified as the disease-causal gene in five different HHT families. In the same centre's non-overlapping 1992–2020 series where 110/134 (82.1%) HHT-causal variants were reported only once, ACVRL1 c.1231C>T (p.Arg411Trp) was identified in nine further families. In a 14-country, four-continent HHT Mutation Database where 181/250 (72.4%) HHT-causal variants were reported only once, ACVRL1 c.1231C>T (p.Arg411Trp) was reported by 12 different laboratories, the adjacent ACVRL1 c.1232G>A (p.Arg411Gln) by 14, and ACVRL1 c.1120C>T (p.Arg374Trp) by 18. Unlike the majority of HHT-causal ACVRL1 variants, these encode ALK1 protein that reaches the endothelial cell surface but fails to signal. Six variants of this type were present in the three series and were reported 6.8–25.5 (mean 8.9) times more frequently than the other ACVRL1 missense variants (all p-values < 0.0039). Noting lower rates of myocardial infarction reported in HHT, we explore potential mechanisms, including a selective paradigm relevant to ALK1′s role in the initiating event of atherosclerosis, where a plausible dominant negative effect of these specific variants can be proposed. In conclusion, there is an ~9-fold excess of kinase-inactive, cell surface-expressed ACVRL1/ALK1 pathogenic missense variants in HHT. The findings support further examination of differential clinical and cellular phenotypes by HHT causal gene molecular subtypes. [ABSTRACT FROM AUTHOR]
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- 2024
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7. Regulatory NADH dehydrogenase‐like complex optimizes C4 photosynthetic carbon flow and cellular redox in maize.
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Zhang, Qiqi, Tian, Shilong, Chen, Genyun, Tang, Qiming, Zhang, Yijing, Fleming, Andrew J., Zhu, Xin‐Guang, and Wang, Peng
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CALVIN cycle , *CARBON 4 photosynthesis , *ELECTRON transport , *COMPARATIVE method , *OXIDATION-reduction reaction - Abstract
Summary: C4 plants typically operate a CO2 concentration mechanism from mesophyll (M) cells into bundle sheath (BS) cells. NADH dehydrogenase‐like (NDH) complex is enriched in the BS cells of many NADP‐malic enzyme (ME) type C4 plants and is more abundant in C4 than in C3 plants, but to what extent it is involved in the CO2 concentration mechanism remains to be experimentally investigated.We created maize and rice mutants deficient in NDH function and then used a combination of transcriptomic, proteomic, and metabolomic approaches for comparative analysis.Considerable decreases in growth, photosynthetic activities, and levels of key photosynthetic proteins were observed in maize but not rice mutants. However, transcript abundance for many cyclic electron transport (CET) and Calvin–Benson cycle components, as well as BS‐specific C4 enzymes, was increased in maize mutants. Metabolite analysis of the maize ndh mutants revealed an increased NADPH : NADP ratio, as well as malate, ribulose 1,5‐bisphosphate (RuBP), fructose 1,6‐bisphosphate (FBP), and photorespiration intermediates.We suggest that by optimizing NADPH and malate levels and adjusting NADP‐ME activity, NDH functions to balance metabolic and redox states in the BS cells of maize (in addition to ATP supply), coordinating photosynthetic transcript abundance and protein content, thus directly regulating the carbon flow in the two‐celled C4 system of maize. [ABSTRACT FROM AUTHOR]
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- 2024
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8. Altering arabinans increases Arabidopsis guard cell flexibility and stomatal opening.
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Carroll, Sarah, Amsbury, Sam, Durney, Clinton H., Smith, Richard S., Morris, Richard J., Gray, Julie E., and Fleming, Andrew J.
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STOMATA , *ARABIDOPSIS - Published
- 2024
- Full Text
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