| 1. |
- 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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| 2. |
- 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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| 3. |
- Chen, Weimin, 1959-, et al.
(författare)
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Spin relaxation in InGaN/Ga(Mn)N quantum wells
- 2005
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Ingår i: Bulletin of the American physical society. - 0003-0503. ; 50, s. 609-609
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Tidskriftsartikel (refereegranskat)abstract
- Proc. 2005 APS March Meeting, March 21-25, 2005; Los Angeles, CA, USA
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| 4. |
- Ferguson, Grant, et al.
(författare)
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Acceleration of Deep Subsurface Fluid Fluxes in the Anthropocene
- 2024
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Ingår i: Earth's Future. - : John Wiley & Sons. - 2328-4277. ; 12:4
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Tidskriftsartikel (refereegranskat)abstract
- The Anthropocene has been framed around humanity's impact on atmospheric, biologic, and near-surface processes, such as land use and vegetation change, greenhouse gas emissions, and the above-ground hydrologic cycle. Groundwater extraction has lowered water tables in many key aquifers but comparatively little attention has been given to the impacts in the deeper subsurface. Here, we show that fluid fluxes from the extraction and injection of fluids associated with oil and gas production and inflow of water into mines likely exceed background flow rates in deep (>500 m) groundwater systems at a global scale. Projected carbon capture and sequestration (CCS), geothermal energy production, and lithium extraction to facilitate the energy transition will require fluid production rates exceeding current oil and co-produced water extraction. Natural analogs and geochemical modeling indicate that subsurface fluid manipulation in the Anthropocene will likely appear in the rock record. The magnitude and importance of these changes are unclear, due to a lack of understanding of how deep subsurface hydrologic and geochemical cycles and associated microbial life interact with the rest of the Earth system.
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| 5. |
- Kim, Tai-Yoo, et al.
(författare)
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Perspectives on the Decelerating Agricultural society
- 2009
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- In general, societies are divided into agricultural and industrial societies. This study presents perspectives on decelerating agricultural societies. Agricultural demand and supply play major roles in the development of societies. Three theories that describe an agricultural society and its deceleration patterns are described: the neo-classical production function and those articulated by Johnston and Mellor as well as induced innovation by Hayami and Ruttan. Two important cases of decelerating agricultural societies, medieval England and the U.S., are investigated through an examination of the process of agricultural society deceleration and ultimate replacement by an industrial society. The limitations of decelerating agricultural societies, with a focus on structural problems,impacts on industrial structure, and problems of agriculture in market and non-market areas, are discussed. The position of agriculture as described by economic development theory is established by analyzing the stages of economic development, the theory ofstructural change, and the theory of leading industry. Finally, the transition from an agricultural to a commercial society is described with a focus on the formation,development, value creation, and structural limitations of a commercial society.
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| 6. |
- McIntosh, Jennifer, et al.
(författare)
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Burial and Denudation Alter Microbial Life at the Bottom of the Hypo‐Critical Zone
- 2023
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Ingår i: Geochemistry Geophysics Geosystems. - : American Geophysical Union (AGU). - 1525-2027. ; 24:6
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Tidskriftsartikel (refereegranskat)abstract
- How subsurface microbial life changed at the bottom of the kilometers-deep (hypo) Critical Zone in response to evolving surface conditions over geologic time is an open question. This study investigates the burial and exhumation, biodegradation, and fluid circulation history of hydrocarbon reservoirs across the Colorado Plateau as a window into the hypo-Critical Zone. Hydrocarbon reservoirs, in the Paradox and Uinta basins, were deeply buried starting ca. 100 to 60 Ma, reaching temperatures >80–140°C, likely sterilizing microbial communities present since the deposition of sediments. High salinities associated with evaporites may have further limited microbial activity. Upward migration of hydrocarbons from shale source rocks into shallower reservoirs during maximum burial set the stage for microbial re-introduction by creating organic-rich “hot spots.” Denudation related to the incision of the Colorado River over the past few million years brought reservoirs closer to the surface under cooler temperatures, enhanced deep meteoric water circulation and flushing of saline fluids, and likely re-inoculated more permeable sediments up to several km depth. Modern- to paleo-hydrocarbon reservoirs show molecular and isotopic evidence of anaerobic oxidation of hydrocarbons coupled to bacterial sulfate reduction in areas with relatively high SO4-fluxes. Anaerobic oil biodegradation rates are high enough to explain the removal of at least some portion of postulated “supergiant oil fields” across the Colorado Plateau by microbial activity over the past several million years. Results from this study help constrain the lower limits of the hypo-Critical Zone and how it evolved over geologic time, in response to changing geologic, hydrologic, and biologic forcings.
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| 7. |
- Pisareva, Tatiana, et al.
(författare)
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Model for Membrane Organization and Protein Sorting in the Cyanobacterium Synechocystis sp. PCC 6803 Inferred from Proteomics and Multivariate Sequence Analyses
- 2011
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Ingår i: Journal of Proteome Research. - : American Chemical Society (ACS). - 1535-3893 .- 1535-3907. ; 10:8, s. 3617-3631
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Tidskriftsartikel (refereegranskat)abstract
- Cyanobacteria are unique eubacteria with an organized subcellular compartmentalization of highly differentiated internal thylakoid membranes (TM), in addition to the outer and plasma membranes (PM). This leads to a complicated system for transport and sorting of proteins into the different membranes and compartments. By shotgun and gel-based proteomics of plasma and thylakoid membranes from the cyanobacterium Synechocystis sp. PCC 6803, a large number of membrane proteins were identified. Proteins localized uniquely in each membrane were used as a platform describing a model for cellular membrane organization and protein intermembrane sorting and were analyzed by multivariate sequence analyses to trace potential differences in sequence properties important for insertion and sorting to the correct membrane. Sequence traits in the C-terminal region, but not in the N-terminal nor in any individual transmembrane segments, were discriminatory between the TM and PM classes. The results are consistent with a contact zone between plasma and thylakoid membranes, which may contain short-lived "hemifusion" protein traffic connection assemblies. Insertion of both integral and peripheral membrane proteins is suggested to occur through common translocons in these subdomains, followed by a potential translation arrest and structure-based sorting into the correct membrane compartment.
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| 8. |
- Shang, Xiaona, et al.
(författare)
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Identification and Chemical Characteristics of Distinctive Chinese Outflow Plumes Associated with Enhanced Submicron Aerosols at the Gosan Climate Observatory
- 2018
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Ingår i: Aerosol and Air Quality Research. - : Taiwan Association for Aerosol Research. - 1680-8584 .- 2071-1409. ; 18:2, s. 330-342
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Tidskriftsartikel (refereegranskat)abstract
- From October till November in 2010 and during March of 2011, when Chinese outflow events were frequently encountered, the chemical composition of submicron particles (PM1.0) was determined hourly using a particle-into-liquid sampler at the Gosan Climate Observatory. Three distinctive pollution plume types were identified: haze aerosols impacted by biomass combustion, nanoparticle bursts associated with outflow from Beijing, and saline soil particles from salt deposits. The highest PM1.0 concentration was observed in a fall haze event, under near-stagnant high-pressure synoptic conditions that were characterized by the lowest visibility (< 5 km) and the highest K+ and OC concentrations, indicating the influence of biomass combustion. When strong high-pressure systems develop in China, they efficiently export fresh urban emissions from Beijing to the study region, as distinguished by nanoparticle bursts of > 10(4) cm(-3) with highly elevated SO2 levels, even during the night. When air masses move rapidly from northeastern China to Gosan under strong wind conditions, the Ca2+ concentration, along with that of Cl- and Na+, is enhanced in PM1.0, which is attributed to the influence of saline transport from dry lakes. The results of this study reveal compositional details and information on both number and mass concentration for different PM1.0 plumes from anthropogenic and natural sources, all of which are associated with different kinds of Chinese outflow events.
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| 9. |
- Stehr, Jan Eric, et al.
(författare)
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Magneto-optical properties of Cr3+ in beta-Ga2O3
- 2021
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Ingår i: Applied Physics Letters. - : AIP Publishing. - 0003-6951 .- 1077-3118. ; 119:5
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Tidskriftsartikel (refereegranskat)abstract
- beta-Ga2O3 is a wide bandgap semiconductor that is attractive for various applications, including power electronics and transparent conductive electrodes. Its properties can be strongly affected by transition metal impurities commonly present during the growth such as Cr. In this Letter, we determine the electronic structure of Cr3+ by performing a correlative study of magneto-photoluminescence (magneto-PL) and electron paramagnetic resonance. We unambiguously prove that the so-called R-1 and R-2 PL lines at around 1.79eV originate from an internal transition between the first excited state (E-2) and the (4)A(2) ground state of Cr3+. The center is concluded to have monoclinic local symmetry and exhibits a large zero-field splitting (similar to 147 mu eV) of the ground state, which can be directly measured from the fine structure of the R1 transition. Furthermore, g-values of the first excited state are accurately determined as g(a) = 1.7, g(b) = 1.5, and g(c*) = 2.1. Our results advance our understanding of the electronic structure of Cr in beta-Ga2O3 and provide a spectroscopic signature of this common residual impurity. (C) 2021 Author(s).
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