| 1. |
- Abelev, Betty, et al.
(författare)
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Long-range angular correlations on the near and away side in p-Pb collisions at root S-NN=5.02 TeV
- 2013
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Ingår i: Physics Letters. Section B: Nuclear, Elementary Particle and High-Energy Physics. - : Elsevier BV. - 0370-2693. ; 719:1-3, s. 29-41
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Tidskriftsartikel (refereegranskat)abstract
- Angular correlations between charged trigger and associated particles are measured by the ALICE detector in p-Pb collisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV for transverse momentum ranges within 0.5 < P-T,P-assoc < P-T,P-trig < 4 GeV/c. The correlations are measured over two units of pseudorapidity and full azimuthal angle in different intervals of event multiplicity, and expressed as associated yield per trigger particle. Two long-range ridge-like structures, one on the near side and one on the away side, are observed when the per-trigger yield obtained in low-multiplicity events is subtracted from the one in high-multiplicity events. The excess on the near-side is qualitatively similar to that recently reported by the CMS Collaboration, while the excess on the away-side is reported for the first time. The two-ridge structure projected onto azimuthal angle is quantified with the second and third Fourier coefficients as well as by near-side and away-side yields and widths. The yields on the near side and on the away side are equal within the uncertainties for all studied event multiplicity and p(T) bins, and the widths show no significant evolution with event multiplicity or p(T). These findings suggest that the near-side ridge is accompanied by an essentially identical away-side ridge. (c) 2013 CERN. Published by Elsevier B.V. All rights reserved.
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| 2. |
- Abelev, Betty, et al.
(författare)
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Measurement of prompt J/psi and beauty hadron production cross sections at mid-rapidity in pp collisions at root s=7 TeV
- 2012
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Ingår i: Journal of High Energy Physics. - 1029-8479. ; :11
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Tidskriftsartikel (refereegranskat)abstract
- The ALICE experiment at the LHC has studied J/psi production at mid-rapidity in pp collisions at root s = 7 TeV through its electron pair decay on a data sample corresponding to an integrated luminosity L-int = 5.6 nb(-1). The fraction of J/psi from the decay of long-lived beauty hadrons was determined for J/psi candidates with transverse momentum p(t) > 1,3 GeV/c and rapidity vertical bar y vertical bar < 0.9. The cross section for prompt J/psi mesons, i.e. directly produced J/psi and prompt decays of heavier charmonium states such as the psi(2S) and chi(c) resonances, is sigma(prompt J/psi) (p(t) > 1.3 GeV/c, vertical bar y vertical bar < 0.9) = 8.3 +/- 0.8(stat.) +/- 1.1 (syst.)(-1.4)(+1.5) (syst. pol.) mu b. The cross section for the production of b-hadrons decaying to J/psi with p(t) > 1.3 GeV/c and vertical bar y vertical bar < 0.9 is a sigma(J/psi <- hB) (p(t) > 1.3 GeV/c, vertical bar y vertical bar < 0.9) = 1.46 +/- 0.38 (stat.)(-0.32)(+0.26) (syst.) mu b. The results are compared to QCD model predictions. The shape of the p(t) and y distributions of b-quarks predicted by perturbative QCD model calculations are used to extrapolate the measured cross section to derive the b (b) over bar pair total cross section and d sigma/dy at mid-rapidity.
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| 3. |
- Chen, Jie, et al.
(författare)
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The modulation of westerlies-monsoon interaction on climate over the monsoon boundary zone in East Asia
- 2021
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Ingår i: International Journal of Climatology. - : Wiley. - 0899-8418 .- 1097-0088. ; 41:S1, s. E3049-E3064
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Tidskriftsartikel (refereegranskat)abstract
- Monsoon boundary zone (MBZ) is a transitional zone between the arid Central Asia (ACA) and humid Asia monsoon area, located in North China-Mongolia. During boreal summer, both the mid-latitude westerlies and East Asian Summer monsoon (EASM) play essential roles in the precipitation variations in the MBZ, via causing anomalous cold air mass from the west and warm/humid air from the south to the MBZ. In this study, we defined a summer westerly index (SWI) over the key westerly domain (35 degrees-42.5 degrees N, 80 degrees-100 degrees E) and an EASM index (EASMI) over the key EASM domain (25 degrees-35 degrees N, 107.5 degrees-125 degrees E) to investigate westerlies-monsoon interaction and their effect on MBZ climate. The results show that westerlies and EASM have a synergistic effect on the precipitation in the MBZ and this synergistic effect could be amplified by the westerlies-monsoon interaction. The westerlies and EASM interaction could induce a local cyclonic anomaly in the MBZ, this cyclonic anomaly further intensifies the westerlies and monsoon flow through a dynamical amplification, favours the precipitation in the MBZ. The MBZ precipitation also contributes to maintain the cyclonic anomaly via the latent heating release. The interannual variability of westerlies is largely modulated by the mid-latitude Silk Road pattern (SRP) and the meridional displacement of the Asian westerly jet (AWJ), and the EASM variability is mainly modulated by El Nino-Southern Oscillation (ENSO), the combined effects from these mid-latitude circulation systems and tropical SST contribute to the climate variability in MBZ.
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| 4. |
- Du, Qian, et al.
(författare)
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Porcine circovirus type 2 infection promotes the SUMOylation of nucleophosmin-1 to facilitate the viral circular single-stranded DNA replication
- 2024
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Ingår i: PLoS Pathogens. - : Public Library of Science (PLoS). - 1553-7366 .- 1553-7374. ; 20:2
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Tidskriftsartikel (refereegranskat)abstract
- The mechanism of genome DNA replication in circular single-stranded DNA viruses is currently a mystery, except for the fact that it undergoes rolling-circle replication. Herein, we identified SUMOylated porcine nucleophosmin-1 (pNPM1), which is previously reported to be an interacting protein of the viral capsid protein, as a key regulator that promotes the genome DNA replication of porcine single-stranded DNA circovirus. Upon porcine circovirus type 2 (PCV2) infection, SUMO2/3 were recruited and conjugated with the K263 site of pNPM1's C-terminal domain to SUMOylate pNPM1, subsequently, the SUMOylated pNPM1 were translocated in nucleoli to promote the replication of PCV2 genome DNA. The mutation of the K263 site reduced the SUMOylation levels of pNPM1 and the nucleolar localization of pNPM1, resulting in a decrease in the level of PCV2 DNA replication. Meanwhile, the mutation of the K263 site prevented the interaction of pNPM1 with PCV2 DNA, but not the interaction of pNPM1 with PCV2 Cap. Mechanistically, PCV2 infection increased the expression levels of Ubc9, the only E2 enzyme involved in SUMOylation, through the Cap-mediated activation of ERK signaling. The upregulation of Ubc9 promoted the interaction between pNPM1 and TRIM24, a potential E3 ligase for SUMOylation, thereby facilitating the SUMOylation of pNPM1. The inhibition of ERK activation could significantly reduce the SUMOylation levels and the nucleolar localization of pNPM1, as well as the PCV2 DNA replication levels. These results provide new insights into the mechanism of circular single-stranded DNA virus replication and highlight NPM1 as a potential target for inhibiting PCV2 replication. Different types of DNA viruses employ different mechanisms to replicate their genome DNA. Porcine circovirus type 2 (PCV2) is the most representative circular single-stranded DNA virus that harms the pig industry all over the world. In this study, we found that the PCV2 Cap interacting protein pNPM1 also interacts with PCV2 DNA in a SUMOylated form to promote PCV2 DNA replication. The SUMOylation of pNPM1 at the conserved K263 site is critical for the interaction of pNPM1 with PCV2 DNA and the replication of PCV2 DNA. Furthermore, we found that PCV2 infection promotes the SUMO2/3 mediated SUMOylation of pNPM1, while does not significantly alter the expression level of pNPM1. PCV2 Cap is the major component that promotes pNPM1 SUMOylation by activating ERK/Ubc9/TRIM24 signalings. These results contribute to a better understanding of the replication mechanism of circular single-stranded DNA viruses, particularly PCV2.
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| 5. |
- Liu, Xintao, et al.
(författare)
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Analysis of urban agglomeration structure through spatial network and mobile phone data
- 2021
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Ingår i: Transactions in GIS. - : Wiley. - 1361-1682 .- 1467-9671. ; 25:4, s. 1949-1969
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Tidskriftsartikel (refereegranskat)abstract
- Urban agglomeration is an important strategy used to promote economic development and urbanization in China. Understanding the structure of urban agglomeration is therefore essential for policy-makers and planners. In this study, the Beijing–Tianjin–Hebei urban agglomeration (BTHUG) is explored through a proposed spatial network analytical framework and a large mobile phone data set (over 20 million users). We first construct a weight-directed spatial interaction network based on an origin–destination matrix derived from the data set. Several network metrics (i.e., degree, strength, the rich-club coefficient, and the assortativity coefficient) and three selected community detection algorithms (i.e., Infomap, Louvain, and Regionalization) are applied and compared to reveal the structure of the BTHUG. A four-level hierarchical structure is defined and observed: one global center, two local centers, major cities that have low mobility flow but strong linkages with the three centers, and peripheral cities that have low mobility flow and weak linkages with the three centers. In particular, the results imply that the spatial structure of the BTHUG is over-dependent on the global center (i.e., Beijing and northern Langfang). Further, ignoring spatial interaction patterns in top-down administrative planning for urban agglomeration may lead to ineffective integrated development. The implications for BTHUG planning are discussed.
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| 6. |
- Niu, Guoxiang, et al.
(författare)
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Effects of nitrogen and water addition on soil carbon, nitrogen, phosphorus, sulfur, and their stoichiometry along soil profile in a semi-arid steppe
- 2023
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Ingår i: Journal of Soils and Sediments. - 1439-0108. ; 23:9, s. 3298-3309
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Tidskriftsartikel (refereegranskat)abstract
- Purpose: Although past studies have found well-constrained soil carbon (C)/nutrient ratios, the effects of increased nitrogen (N) and water inputs on these ratios across soil depths have rarely been assessed in semi-arid grasslands. Methods: In this study, we evaluated the contents of total C, N, phosphorus (P), sulfur (S), and their stoichiometric ratios in a 0–80 cm soil profile following 13 years of successive N (at rates of 5 and 15 g m−2 yearr−1) and water addition (180 mm per growing season) in a semi-arid grassland of the Mongolian Plateau. Results: In the 0–10 cm soil layer, long-term N addition tended to increase total C and N contents but decreased soil total P and S contents compared to the control. The effects of N addition, as observed in 0–10 cm soil, however, were not consistent with that in the deep 10–80 cm soil layers. Water addition increased the total C, N, and P contents across the entire soil profile but increased total S content only in 0–40 cm soil. Moreover, the combined addition of N and water generally had stronger effects on the four elements across the whole soil profile. For the stoichiometry of the four elements, a low rate of N addition (5 g m−2 year−1) increased soil C:N ratios and decreased soil P:S ratios in the 0–80 cm soils, but a high rate of N addition (15 g m−2 year−1) produced the opposite effect. Both N addition rates resulted in an increase in the soil C:P, C:S, N:P, and N:S ratios. Similarly, in plots that received water, water addition alone decreased the soil C:N ratios, while N addition caused higher fluctuations in these six elemental ratios. However, there was no consistent pattern of change in any one ratio, independent of the addition of water, when taking into account N addition rates and soil depths. Conclusion: Our findings showed that the effects of N addition on soil total C, N, P, and S contents and their stoichiometric ratios were highly influenced by the rate of N addition and the depth of soil, and that these effects could be modulated by increasing precipitation. These results need to be carefully considered while managing the ecological environment in semi-arid steppes.
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| 7. |
- Niu, Guoxiang, et al.
(författare)
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Nitrogen addition and mowing had only weak interactive effects on macronutrients in plant-soil systems of a typical steppe in Inner Mongolia
- 2023
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Ingår i: Journal of Environmental Management. - 0301-4797. ; 347
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Tidskriftsartikel (refereegranskat)abstract
- Effective management of macronutrients is pivotal in the optimization and provisioning of ecosystem services in grassland areas, particularly in degraded grasslands. In such instances where mowing and nitrogen (N) fertilization have emerged as predominant management strategies, nutrient management is especially important. However, the precise effects of these concurrent practices on the distribution of macronutrients in plant-soil systems remain unclear. Here we evaluated the effects of 12 years of N addition (2, 10, and 50 g N m−2 year−1) and mowing on the concentrations and pools of six macronutrients (i.e., N; phosphorus P; sulfur S, calcium Ca, magnesium Mg, and potassium K) in three plant components (aboveground plants, litter, and belowground roots) at the community level and in the soil in a typical steppe in Inner Mongolia. Our results revealed that N addition generally raised the N concentration in the entire plant-soil system, regardless of whether plots were mowed. Higher N addition (10 and 50 g N m−2 year−1) also led to higher concentrations of P (+22%, averaging two N addition rates), S (+16%), K (+22%), Ca (+22%), and Mg (+24%) in plants but lower concentrations of these nutrients in the litter. Similar decreases in K (−9%), Ca (−46%), and Mg (−8%) were observed in the roots. In light of the observed increases in vegetation biomass and the lack of pronounced changes in soil bulk density, we found that the ecosystem N enrichment resulted in increased pools of all measured macronutrients in plants, litter, and roots (with the exception of Ca in the roots) while concurrently decreased the pools of P (−20%, averaging two higher N addition rates), S (−12%), K (−10%), Ca (−37%), and Mg (−19%) in the soil, with no obvious effect of the mowing practice. Overall, mowing exhibited a very limited capacity to alleviate the effects of long-term N addition on macronutrients in the plant-soil system. These findings highlight the importance of considering the distribution of macronutrients across distinct plant organs and the dynamic nutrient interplay between plants and soil, particularly in the context of long-term fertilization and mowing practices, when formulating effective grassland management strategies.
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| 8. |
- Wu, Bo, et al.
(författare)
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Strong self-trapping by deformation potential limits photovoltaic performance in bismuth double perovskite
- 2021
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Ingår i: Science Advances. - : American Association for the Advancement of Science. - 2375-2548. ; 7:8
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Tidskriftsartikel (refereegranskat)abstract
- Bismuth-based double perovskite Cs2AgBiBr6 is regarded as a potential candidate for low-toxicity, high-stability perovskite solar cells. However, its performance is far from satisfactory. Albeit being an indirect bandgap semiconductor, we observe bright emission with large bimolecular recombination coefficient (reaching 4.5 +/- 0.1 x 10(-11) cm(3) s(-1)) and low charge carrier mobility (around 0.05 cm(2) s(-1) V-1). Besides intermediate Frohlich couplings present in both Pb-based perovskites and Cs2AgBiBr6, we uncover evidence of strong deformation potential by acoustic phonons in the latter through transient reflection, time-resolved terahertz measurements, and density functional theory calculations. The Frohlich and deformation potentials synergistically lead to ultrafast self-trapping of free carriers forming polarons highly localized on a few units of the lattice within a few picoseconds, which also breaks down the electronic band picture, leading to efficient radiative recombination. The strong self-trapping in Cs2AgBiBr6 could impose intrinsic limitations for its application in photovoltaics.
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| 9. |
- Xu, Lei, et al.
(författare)
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The Role of Solution Aggregation Property toward High-Efficiency Non-Fullerene Organic Photovoltaic Cells
- 2024
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Ingår i: Advanced Materials. - : WILEY-V C H VERLAG GMBH. - 0935-9648 .- 1521-4095.
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Tidskriftsartikel (refereegranskat)abstract
- In organic photovoltaic cells, the solution-aggregation effect (SAE) is long considered a critical factor in achieving high power-conversion efficiencies for polymer donor (PD)/non-fullerene acceptor (NFA) blend systems. However, the underlying mechanism has yet to be fully understood. Herein, based on an extensive study of blends consisting of the representative 2D-benzodithiophene-based PDs and acceptor-donor-acceptor-type NFAs, it is demonstrated that SAE shows a strong correlation with the aggregation kinetics during solidification, and the aggregation competition between PD and NFA determines the phase separation of blend film and thus the photovoltaic performance. PDs with strong SAEs enable earlier aggregation evolutions than NFAs, resulting in well-known polymer-templated fibrillar network structures and superior PCEs. With the weakening of PDs' aggregation effects, NFAs, showing stronger tendencies to aggregate, tend to form oversized domains, leading to significantly reduced external quantum efficiencies and fill factors. These trends reveal the importance of matching SAE between PD and NFA. The aggregation abilities of various materials are further evaluated and the aggregation ability/photovoltaic parameter diagrams of 64 PD/NFA combinations are provided. This work proposes a guiding criteria and facile approach to match efficient PD/NFA systems. A systematic study of the representative organic photovoltaic systems shows that the aggregation competition between polymer donor (PD) and non-fullerene acceptor (NFA) is a decisive factor in the phase separation of blend film and thus the photovoltaic performance. Based on 64 PD/NFA combinations, the aggregation ability/photovoltaic parameter heatmaps are plotted, providing a new matching rule for developing high-efficiency PD/NFA systems. image
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| 10. |
- Yuan, Jun, et al.
(författare)
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Reducing Voltage Losses in the A-DAD-A Acceptor-Based Organic Solar Cells
- 2020
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Ingår i: Chem. - : CELL PRESS. - 2451-9308 .- 2451-9294. ; 6:9, s. 2147-2161
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Tidskriftsartikel (refereegranskat)abstract
- Power conversion efficiencies (PCEs) of solution-processed organic solar cells (OSCs) have recently reached 17.4% (certified) for single-junction devices. Crucial to this advancement is the development of non-fullerene acceptors (NFAs) since 2015. The recent A-DAD-A NFAs have attracted widespread attention because of their ladder-type electron-deficient-core-based central fused ring with improved transport properties and optimum energy levels. With the synergistic effect of electron-deficient-core and specific molecular geometry, the A-DADA molecules could achieve low voltage losses and high current generation at the same time, reaching new regimes of device physics and photophysics. This perspective will discuss the voltage losses in state-of-the-art A-DAD-A NFA-based OSCs and propose new molecular design strategies to achieve PCEs over 20% in OSCs based on these new acceptors by further decreasing their total voltage losses.
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