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| 2. |
- Qi, Di, et al.
(författare)
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Climate change drives rapid decadal acidification in the Arctic Ocean from 1994 to 2020
- 2022
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 377:6614, s. 1544-1550
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Tidskriftsartikel (refereegranskat)abstract
- The Arctic Ocean has experienced rapid warming and sea ice loss in recent decades, becoming the first open-ocean basin to experience widespread aragonite undersaturation [saturation state of aragonite (Warag) < 1]. However, its trend toward long-term ocean acidification and the underlying mechanisms remain undocumented. Here, we report rapid acidification there, with rates three to four times higher than in other ocean basins, and attribute it to changing sea ice coverage on a decadal time scale. Sea ice melt exposes seawater to the atmosphere and promotes rapid uptake of atmospheric carbon dioxide, lowering its alkalinity and buffer capacity and thus leading to sharp declines in pH and Warag. We predict a further decrease in pH, particularly at higher latitudes where sea ice retreat is active, whereas Arctic warming may counteract decreases in Warag in the future.
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| 3. |
- Wang, Longxin, et al.
(författare)
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Telomere-to-telomere and haplotype-resolved genome assembly of the Chinese cork oak (Quercus variabilis)
- 2023
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Ingår i: Frontiers in Plant Science. - : Frontiers Media S.A.. - 1664-462X. ; 14
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Tidskriftsartikel (refereegranskat)abstract
- The Quercus variabilis, a deciduous broadleaved tree species, holds significant ecological and economical value. While a chromosome-level genome for this species has been made available, it remains riddled with unanchored sequences and gaps. In this study, we present a nearly complete comprehensive telomere-to-telomere (T2T) and haplotype-resolved reference genome for Q. variabilis. This was achieved through the integration of ONT ultra-long reads, PacBio HiFi long reads, and Hi-C data. The resultant two haplotype genomes measure 789 Mb and 768 Mb in length, with a contig N50 of 65 Mb and 56 Mb, and were anchored to 12 allelic chromosomes. Within this T2T haplotype-resolved assembly, we predicted 36,830 and 36,370 protein-coding genes, with 95.9% and 96.0% functional annotation for each haplotype genome. The availability of the T2T and haplotype-resolved reference genome lays a solid foundation, not only for illustrating genome structure and functional genomics studies but also to inform and facilitate genetic breeding and improvement of cultivated Quercus species.
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| 4. |
- He, Haoran, et al.
(författare)
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Deciphering microbiomes dozens of meters under our feet and their edaphoclimatic and spatial drivers
- 2024
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Ingår i: Global Change Biology. - 1354-1013. ; 30:1
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Tidskriftsartikel (refereegranskat)abstract
- Microbes inhabiting deep soil layers are known to be different from their counterpart in topsoil yet remain under investigation in terms of their structure, function, and how their diversity is shaped. The microbiome of deep soils (>1 m) is expected to be relatively stable and highly independent from climatic conditions. Much less is known, however, on how these microbial communities vary along climate gradients. Here, we used amplicon sequencing to investigate bacteria, archaea, and fungi along fifteen 18-m depth profiles at 20–50-cm intervals across contrasting aridity conditions in semi-arid forest ecosystems of China's Loess Plateau. Our results showed that bacterial and fungal α diversity and bacterial and archaeal community similarity declined dramatically in topsoil and remained relatively stable in deep soil. Nevertheless, deep soil microbiome still showed the functional potential of N cycling, plant-derived organic matter degradation, resource exchange, and water coordination. The deep soil microbiome had closer taxa–taxa and bacteria–fungi associations and more influence of dispersal limitation than topsoil microbiome. Geographic distance was more influential in deep soil bacteria and archaea than in topsoil. We further showed that aridity was negatively correlated with deep-soil archaeal and fungal richness, archaeal community similarity, relative abundance of plant saprotroph, and bacteria–fungi associations, but increased the relative abundance of aerobic ammonia oxidation, manganese oxidation, and arbuscular mycorrhizal in the deep soils. Root depth, complexity, soil volumetric moisture, and clay play bridging roles in the indirect effects of aridity on microbes in deep soils. Our work indicates that, even microbial communities and nutrient cycling in deep soil are susceptible to changes in water availability, with consequences for understanding the sustainability of dryland ecosystems and the whole-soil in response to aridification. Moreover, we propose that neglecting soil depth may underestimate the role of soil moisture in dryland ecosystems under future climate scenarios.
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| 5. |
- Wang, Yuwen, et al.
(författare)
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Fast room-temperature hydrogenation of nitroaromatics on Pd nanocrystal-boron cluster/graphene oxide nanosheets
- 2022
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Ingår i: Molecular Catalysis. - : Elsevier. - 2468-8231. ; 529
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Tidskriftsartikel (refereegranskat)abstract
- The reduction of nitroaromatics to aminoaromatics is essential for fine chemical production and effective sewage treatment. However, the activity of an external catalyst is essential for the reaction. In this study, Pd nanocrystals were anchored in situ on two-dimensional graphene oxide (GO), which acted as a catalyst support with high specific surface area. The oxygen-containing groups on the surface of GO bonded to the functionally rich boron clusters through hydrogen bonding interactions. A mildly reducible closed-dodecahydrododecaboric acid anion cluster (closo‑[B12H12]2–) was employed as the target site. The mild reducibility of closo‑[B12H12]2– resulted in a wide dispersion of ultrafine Pd nanocrystals on GO. Under ambient conditions, Pd/BGO rapidly hydrogenated nitroaromatics, such as 4-nitrophenol, to aminoaromatics with approximately 100% efficiency. Moreover, Pd/BGO retained its high catalytic activity for the hydrogenation/reduction of 4-nitrophenol after five catalytic cycles. Therefore, Pd/BGO could be a promising and economically viable candidate for various practical applications. The proposed innovative preparation strategy and highly efficient catalytic activity suggested the effective performance of closo‑[B12H12]2– as nanometal nucleation target sites. In addition to providing an alternate route for preparing supported nanometals, this study presents a stable and efficient catalyst for the hydrogenation of nitroaromatics.
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| 6. |
- Zhao, Xue, et al.
(författare)
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Electron modulation and morphology engineering jointly accelerate oxygen reaction to enhance Zn-Air battery performance
- 2023
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Ingår i: Advanced Science. - : John Wiley & Sons. - 2198-3844. ; 10:8
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Tidskriftsartikel (refereegranskat)abstract
- Combining morphological control engineering and diatomic coupling strategies, heteronuclear Fe-Co bimetals are efficiently intercalated into nitrogen-doped carbon materials with star-like to simultaneously accelerate oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). The half-wave potential and kinetic current density of the ORR driven by FeCoNC/SL surpass the commercial Pt/C catalyst. The overpotential of OER is as low as 316 mV (η10), and the mass activity is at least 3.2 and 9.4 times that of mononuclear CoNC/SL and FeNC/SL, respectively. The power density and specific capacity of the Zn-air battery with FeCoNC/SL as air cathode are as high as 224.8 mW cm−2 and 803 mAh g−1, respectively. Morphologically, FeCoNC/SL endows more reactive sites and accelerates the process of oxygen reaction. Density functional theory reveals the active site of the heteronuclear diatomic, and the formation of FeCoN5C configuration can effectively tune the d-band center and electronic structure. The redistribution of electrons provides conditions for fast electron exchange, and the change of the center of the d-band avoids the strong adsorption of intermediate species to simultaneously take into account both ORR and OER and thus achieve high-performance Zn-air batteries.
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| 7. |
- Arghavani, Abbas, et al.
(författare)
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Power-Adaptive Communication With Channel-Aware Transmission Scheduling in WBANs
- 2024
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Ingår i: IEEE Internet of Things Journal. - : Institute of Electrical and Electronics Engineers (IEEE). - 2327-4662. ; 11:9, s. 16087-16102
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Tidskriftsartikel (refereegranskat)abstract
- Radio links in wireless body area networks (WBANs) are highly subject to short and long-term attenuation due to the unstable network topology and frequent body blockage. This instability makes it challenging to achieve reliable and energy-efficient communication, but on the other hand, provides a great potential for the sending nodes to dynamically schedule the transmissions at the time with the best expected channel quality. Motivated by this, we propose improved Gilbert-Elliott Markov chain model (IGE), a memory-efficient Markov chain model to monitor channel fluctuations and provide a long-term channel prediction. We then design adaptive transmission power selection (ATPS), a deadline-constrained channel scheduling scheme that enables a sending node to buffer the packets when the channel is bad and schedule them to be transmitted when the channel is expected to be good within a deadline. ATPS can self-learn the pattern of channel changes without imposing a significant computation or memory overhead on the sending node. We evaluate the performance of ATPS through experiments using TelosB motes under different scenarios with different body postures and packet rates. We further compare ATPS with several state-of-the-art schemes, including the optimal scheduling policy, in which the optimal transmission time for each packet is calculated based on the collected received signal strength indicator (RSSI) samples in an off-line manner. The experimental results reveal that ATPS performs almost as efficiently as the optimal scheme in high-date-rate scenarios and has a similar trend on power level usage.
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| 8. |
- Barnard, Yvonne, et al.
(författare)
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Data management and data sharing in field operational tests
- 2016
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Ingår i: Intelligent Transportation Systems: From Good Practices to Standards. - : CRC Press. - 9781498721875 ; , s. 59-72
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- In this chapter it will be discussed how data from Field Operational Tests of Intelligent Transport Systems can be managed and shared. The Field Operational Tests, where hundreds of users get to experience the latest systems, aim to assess the impacts that would result from a wide-scale implementation. Evaluation principles of Field Operational Tests will be explained, and a closer look will be taken at the data that is collected for carrying out the assessments. The widely used FESTA methodology for designing and conducting Field Operational Tests and Naturalistic Driving Studies already provides several recommendations for managing data. This methodology will be discussed and illustrated by examples of its use in European projects. As field test projects set out to collect a huge set of data, the projects themselves do not usually have the scope or the resources to analyze the data from every perspective. Therefore re-use of the collected data also by other projects with different research questions has the potential to generate a wealth of new knowledge about what is happening in the interactions between drivers, vehicles and the infrastructure. Data sharing is the focus of a European support action, FOT-Net Data. The support action is working, with international collaboration, to form a data sharing framework, a data catalogue, and provide detailed recommendations for sharing and re-use. Outcomes from this activity will be discussed. Ways of sharing different types of data will be described, including the necessary steps to be taken to open up the data.
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| 9. |
- Chen, Chao, et al.
(författare)
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Effects of Salt Tracer Amount, Concentration and Kind on the Fluid Flow Behavior in a Hydrodynamic Model of Continuous Casting Tundish
- 2012
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Ingår i: Steel Research International. - : John Wiley & Sons. - 1611-3683 .- 1869-344X. ; 83:12, s. 1141-1151
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Tidskriftsartikel (refereegranskat)abstract
- The hydrodynamic modeling method that widely used to simulate the fluid flow was reconsidered and discussed in this paper. The effects of injected salt tracer amount, concentration and kind on the fluid flow behavior in a hydrodynamic model tundish were investigated. The results were compared with the mathematical modeling calculation results, that the tracer density effect was eliminated. The residence time distribution (RTD) curve of tracer introduced deviated to the left side of the calculated curve, besides the deviation was increased as dimensionless tracer amount (the ratio of tracer amount to hydrodynamic model tundish volume) increased from 0.202 × 10−3 to 1.008 × 10−3. The results of tracer concentration study were similar, namely the deviation was increased with concentration increased; on the other hand, the deformation of a “stair-shape” RTD curve occurred when tracer concentration was much lower (at dimensionless tracer amount of 0.168 × 10−3 with converting to saturated solution). Besides, the effect of tracer kind on the accuracy of hydrodynamic modeling was also studied; the measurements of KCl solution with lower density than that of NaCl solution exhibited more of accuracy. Finally, the optimized tracer in hydrodynamic model tundish of present work is saturated KCl solution with dimensionless tracer amount of 0.202 × 10−3.
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| 10. |
- Chen, Yawen, et al.
(författare)
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A Novel P-shape Tessellation Approach on Double-Loop Networks
- 2009
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Ingår i: 2009 IEEE INTERNATIONAL SYMPOSIUM ON IT IN MEDICINE & EDUCATION, VOLS 1 AND 2, PROCEEDINGS. - NEW YORK : IEEE. - 9781424439294 ; , s. 507-511
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Konferensbidrag (refereegranskat)abstract
- Double loop computer networks are widely used in the design and implementation of local area networks and parallel processing architectures. However the embedding problems on double-loop networks have not been well studied due to the complexity of double-loop networks. Since the traditional L-shape, designed to compute the diameter of double-loop networks, is not efficient to solve embedding problems, we propose a novel tessellation approach to partition the geometric plane of double-loop networks into a set of parallelogram shaped tiles, called P-shape. Our proposed tessellation technique, P-shape, is a useful theoretical tool for embedding meshes on double-loop networks, and can be extended to analyze other problems as a bridge between regular graphs and double-loop networks.
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