In order to examine experimentally the kinetics of the reactive diffusion between solid Cu and liquid Al, Cu/Al diffusion couples were isothermally annealed in the temperature range between
T
=
973 ...and 1073
K. Owing to annealing, compound layers consisting of the β, γ
1 and ɛ
2 phases are produced between the Cu-rich solid (α) and Al-rich liquid (L) phases. The β, γ
1 and ɛ
2 phases are the only stable compounds at
T
=
973–1073
K. The mean thickness of each compound layer is proportional to a power function of the annealing time. For the β layer, the exponent of the power function is close to 0.5 at
T
=
1023–1073
K, but nearly equal to 0.25 at
T
=
973
K. On the other hand, for the γ
1 layer, the exponent takes values between 0.25 and 0.5 at
T
=
1023–1073
K, but that smaller than 0.25 at
T
=
973
K. The exponent smaller than 0.5 indicates that grain boundary diffusion predominantly controls the growth of the compound layer and grain growth occurs at a certain rate. In contrast, the ɛ
2/L interface migrates towards the α phase. The migration distance of the ɛ
2/L interface is much greater than the total thickness of the compound layers, and proportional to the square root of the annealing time. Consequently, the migration of the ɛ
2/L interface is governed by interdiffusion in the L phase. According to estimation, the interdiffusion coefficient is much greater for the L phase than for the solid phases. As a result, the ɛ
2/L interface migrates towards the α phase, and the migration rate of the interface is much greater than the overall growth rate of the compound layers.
Plant-specific NAC transcription factors (TFs) play important roles in regulating diverse biological processes, including development, senescence, growth, cell division and responses to environmental ...stress stimuli. Within the soybean genome, we identified 152 full-length GmNAC TFs, including 11 membrane-bound members. In silico analysis of the GmNACs, together with their Arabidopsis and rice counterparts, revealed similar NAC architecture. Next, we explored the soybean Affymetrix array and Illumina transcriptome sequence data to analyse tissue-specific expression profiles of GmNAC genes. Phylogenetic analysis using stress-related NAC TFs from Arabidopsis and rice as seeding sequences identified 58 of the 152 GmNACs as putative stress-responsive genes, including eight previously reported dehydration-responsive GmNACs. We could design gene-specific primers for quantitative real-time PCR verification of 38 out of 50 newly predicted stress-related genes. Twenty-five and six GmNACs were found to be induced and repressed 2-fold or more, respectively, in soybean roots and/or shoots in response to dehydration. GmNAC085, whose amino acid sequence was 39%; identical to that of well-known SNAC1/ONAC2, was the most induced gene upon dehydration, showing 390-fold and 20-fold induction in shoots and roots, respectively. Our systematic analysis has identified excellent tissue-specific and/or dehydration-responsive candidate GmNAC genes for in-depth characterization and future development of improved drought-tolerant transgenic soybeans.
Performance of the OEDO beamline Hwang, J W; Michimasa, S; Yamada, K ...
Journal of physics. Conference series,
12/2020, Volume:
1643, Issue:
1
Journal Article
Peer reviewed
Open access
The OEDO (Optimized Energy Degrading Optics for RI beam) beamline has been developed to obtain low-energy (10 - 50 MeV/u) RI beams by slowing down the secondary beams at RIBF, RIKEN. Such beams are ...useful probes to investigate nuclear structure by means of nucleon transfer and Coulomb excitation reactions. The beamline is designed to produce a well-focused beam of small energy spread with the help of the angle-tuneable wedge degrader and the radio-frequency deflector. The commissioning and first physics experiments using the OEDO beamline were carried out in 2017. OEDO successfully provided the energy-degraded beams of Se, Zr, and Pd. Its performance including the optics and transmission was evaluated using those experimental data and it functions properly as designed. We expect that our novel beamline shed a light on the experimental approaches involving nuclear reactions at several tens of MeV/u to expand our knowledge of nuclei far beyond the line of stability.
Theoretical models on the movement of colonial animals predict that neighbouring colonies may segregate their foraging areas, and many seabird studies have reported the presence of such segregations. ...However, these studies have often lacked the appropriate null model to test the effect of neighbouring colonies on foraging areas, especially in small colonies or in short‐ranging species. Here, we examined the foraging areas of Adélie Penguins Pygoscelis adeliae from two neighbouring (2 km apart) colonies by using bird‐borne GPS loggers. The field study was conducted at Hukuro Cove colony (104 pairs) and Mizukuguri Cove colony (338 pairs) in Lützow‐Holm Bay, East Antarctica. We obtained GPS tracks for 504 foraging trips from 48 chick‐rearing Adélie Penguins and quantified the degree of overlap in the foraging areas between two colonies. We also produced simulated movement tracks by using correlated random‐walks assuming no inter‐colony competition and quantified the degree of overlap in the simulated foraging areas. Finally, we compared the results from real GPS tracks with those from simulated tracks to examine the effect of neighbouring colonies on Adélie Penguin movement. The results indicate that the degree of overlap was significantly smaller in real tracks than in simulated tracks. In real tracks, the foraging area of the smaller Hukuro Cove colony extended to the other side of the larger Mizukuguri Cove colony, unlike in simulated tracks. Consequently, we suggest that Adélie Penguins from two neighbouring colonies segregated their foraging areas and that the larger colony appeared to affect the foraging area of the smaller colony.
Melatonin may have beneficial effects when used in oocyte maturation and embryo development culture. The effect of melatonin during IVM on meiosis resumption and progression in bovine oocytes and on ...expression of antioxidant enzymes, nuclear fragmentation and free radicals, as well as on embryo development were assessed. Cumulus-oocyte complexes were matured in vitro with melatonin (10−9 and 10−6 M), FSH (positive control), or without hormones (negative control) in defined medium. Maturation rates were evaluated at 6, 12, 18, and 24 hours. Transcripts for antioxidant enzymes (CuZnSOD, MnSOD, and glutathione peroxidase 4 (GPX4)) in oocytes and cumulus cells, nuclear fragmentation in cumulus cells (TUNEL) and reactive oxygen species levels in oocytes (carboxy-H2 difluorofluorescein diacetate) were determined at 24 hours IVM. Effect of treatments on embryo development was determined after in vitro fertilization and culture. At 12 hours, meiosis resumption rates in FSH and melatonin-treated groups were similar (69.6%–81.8%, P > 0.05). At 24 hours, most oocytes were in metaphase II, with FSH showing highest rates (90.0%, P < 0.05) compared with the other groups (51.6%–69.1%, P > 0.05). In cumulus cells, MnSOD expression was higher in FSH group (P < 0.05) whereas Cu,ZnSOD transcripts were more abundant in melatonin group (10−6M; P < 0.05). Nuclear fragmentation in cumulus cells was highest in controls (37.4%/10,000 cells; P < 0.05) and lower in FSH and 10−6M melatonin (29.4% and 25.6%/10,000 cells, respectively). Reactive oxygen species levels were lower in oocytes matured with 10−6M melatonin than in control and FSH groups (P < 0.05). Embryo development from oocytes matured only with melatonin was similar to those matured in complete medium (P > 0.05). In conclusion, although melatonin during IVM in a defined medium does not stimulate nuclear maturation progression it does stimulate meiosis resumption and such treated oocytes support subsequent embryo development. Melatonin also shows cytoprotective effects on cumulus-oocyte complexes.
When a steep, breaking wave hits a vertical sea wall in shallow water, a flip-through event may occur, leading to the formation of an up-rushing planar jet. During such an event, a jet of water is ...ejected at a speed many times larger than the approaching wave’s celerity. As the jet rises, the bounded fluid sheet ruptures to form vertical ligaments which subsequently break up to form droplets, creating a polydisperse spray. Experiments in the University of Hokkaido’s 24 m flume measured the resulting droplet sizes using image analysis of high-speed video. Consideration of the mechanisms forming spray droplets shows that the number density of droplet sizes is directly proportional to a power p of the droplet radius: where p=−5/2 during the early break-up stage and p=−2 for the fully fragmented state. This was confirmed by experimental observations. Here, we show that the recorded droplet number density follows the lognormal probability distribution with parameters related to the elapsed time since the initial wave impact. This statistical model of polydisperse spray may provide a basis for modelling droplet advection during wave overtopping events, allowing atmospheric processes leading to enhanced fluxes of mass, moisture, heat and momentum in the spray-mediated marine boundary layer over coasts to be described.
Increasing marine uptake of anthropogenic CO2 (Cant) causes global ocean acidification. To obtain a high‐resolution spatiotemporal distribution of oceanic carbon chemistry, we developed new ...parameterizations of the seawater total alkalinity, and dissolved inorganic carbon from the ocean's surface to 2,000‐m depth by using dissolved oxygen, water temperature (T), salinity (S), and pressure (P) data. Using the values of total alkalinity and dissolved inorganic carbon predicted by dissolved oxygen, T, S, and P data derived from autonomous biogeochemical Argo floats, we described the distribution of oceanic Cant in the 2000s in the subarctic North Pacific at high spatiotemporal resolution. The Cant was found about 300 m deeper than during the 1990s; its average inventory to 2,000 m was 24.8 ± 10.2 mol/m2, about 20% higher than the 1990s average. Future application of parameterizations to global biogeochemical Argo floats data should allow the detailed global mapping of spatiotemporal distributions of CO2 parameters.
Plain Language Summary
Ocean absorbs the increasing atmospheric CO2 by human activities from 1750s and encourages global ocean acidification. To obtain the human‐activity‐derived CO2 in the subarctic North Pacific in a high resolution, we applied our empirical ocean carbon chemistry equations using other hydrographic parameters to autonomous biogeochemical Argo floats data. The amount of human‐activity‐derived CO2 in this region was found about 300 m deeper than during the 1990s and about 20% higher than the 1990s average. Our method allows the development of a system for monitoring long‐term trend changes in ocean carbon chemistry similar to other time series stations.
Key Points
New parameterizations for total alkalinity and dissolved inorganic carbon allow higher‐resolution estimates of oceanic anthropogenic CO2
Applying our parameterizations to autonomous biogeochemical Argo floats data could allow more detailed mapping of parameters influencing global oceanic CO2 cycles
ABSTRACT
The current generation of (sub)mm-telescopes has allowed molecular line emission to become a major tool for studying the physical, kinematic, and chemical properties of extragalactic ...systems, yet exploiting these observations requires a detailed understanding of where emission lines originate within the Milky Way. In this paper, we present 60 arcsec (∼3 pc) resolution observations of many 3 mm band molecular lines across a large map of the W49 massive star-forming region (∼100 pc × 100 pc at 11 kpc), which were taken as part of the ‘LEGO’ IRAM-30m large project. We find that the spatial extent or brightness of the molecular line transitions are not well correlated with their critical densities, highlighting abundance and optical depth must be considered when estimating line emission characteristics. We explore how the total emission and emission efficiency (i.e. line brightness per H2 column density) of the line emission vary as a function of molecular hydrogen column density and dust temperature. We find that there is not a single region of this parameter space responsible for the brightest and most efficiently emitting gas for all species. For example, we find that the HCN transition shows high emission efficiency at high column density (1022 cm−2) and moderate temperatures (35 K), whilst e.g. N2H+ emits most efficiently towards lower temperatures (1022 cm−2; <20 K). We determine $X_{\mathrm{CO} (1-0)} \sim 0.3 \times 10^{20} \, \mathrm{cm^{-2}\, (K\, km\, s^{-1})^{-1}}$, and $\alpha _{\mathrm{HCN} (1-0)} \sim 30\, \mathrm{M_\odot \, (K\, km\, s^{-1}\, pc^2)^{-1}}$, which both differ significantly from the commonly adopted values. In all, these results suggest caution should be taken when interpreting molecular line emission.
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