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1.
  • Abazov, V. M., et al. (author)
  • The upgraded DO detector
  • 2006
  • In: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 565:2, s. 463-537
  • Journal article (peer-reviewed)abstract
    • The DO experiment enjoyed a very successful data-collection run at the Fermilab Tevatron collider between 1992 and 1996. Since then, the detector has been upgraded to take advantage of improvements to the Tevatron and to enhance its physics capabilities. We describe the new elements of the detector, including the silicon microstrip tracker, central fiber tracker, solenoidal magnet, preshower detectors, forward muon detector, and forward proton detector. The uranium/liquid -argon calorimeters and central muon detector, remaining from Run 1, are discussed briefly. We also present the associated electronics, triggering, and data acquisition systems, along with the design and implementation of software specific to DO.
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2.
  • Abazov, V. M., et al. (author)
  • Measurement of the t(t)over-bar production cross section in p(p)over-bar collisions at root s=1.96 TeV using secondary vertex b tagging
  • 2006
  • In: Physical Review D - Particles, Fields, Gravitation and Cosmology. - 1550-7998 .- 1550-2368. ; 74:11, s. 112004-
  • Journal article (peer-reviewed)abstract
    • We report a new measurement of the t (t) over bar production cross section in p (beta) over bar collisions at a center-of-mass energy of 1.96 TeV using events with one charged lepton (electron or muon), missing transverse energy, and jets. Using 425 pb(-1) of data collected using the D0 detector at the Fermilab Tevatron Collider, and enhancing the t (t) over bar content of the sample by tagging b jets with a secondary vertex tagging algorithm, the t (t) over bar production cross section is measured to be sigma(p (t) over bar -> t (t) over bar +X)=6.6 +/- 0.9(stat+syst) +/- 0.4(lum) pb. This cross section is the most precise D0 measurement to date for t (t) over bar production and is in good agreement with standard model expectations.
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3.
  • Fukuzawa, H., et al. (author)
  • Deep Inner-Shell Multiphoton Ionization by Intense X-Ray Free-Electron Laser Pulses
  • 2013
  • In: Physical Review Letters. - 1079-7114 .- 0031-9007. ; 110:17
  • Journal article (peer-reviewed)abstract
    • We have investigated multiphoton multiple ionization dynamics of xenon atoms using a new x-ray free-electron laser facility, SPring-8 Angstrom Compact free electron LAser (SACLA) in Japan, and identified that Xen+ with n up to 26 is produced at a photon energy of 5.5 keV. The observed high charge states (n >= 24) are produced via five-photon absorption, evidencing the occurrence of multiphoton absorption involving deep inner shells. A newly developed theoretical model, which shows good agreement with the experiment, elucidates the complex pathways of sequential electronic decay cascades accessible in heavy atoms. The present study of heavy-atom ionization dynamics in high-intensity hard-x-ray pulses makes a step forward towards molecular structure determination with x-ray free-electron lasers. DOI: 10.1103/PhysRevLett.110.173005
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4.
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5.
  • Motomura, K., et al. (author)
  • Sequential multiphoton multiple ionization of atomic argon and xenon irradiated by X-ray free-electron laser pulses from SACLA
  • 2013
  • In: Journal of Physics B: Atomic, Molecular and Optical Physics. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 46:16
  • Journal article (peer-reviewed)abstract
    • We have investigated multiphoton multiple ionization of argon and xenon atoms at 5 keV using a new x-ray free electron laser (XFEL) facility, the SPring-8 Angstrom Compact free electron LAser (SACLA) in Japan. The experimental results are compared with the new theoretical results presented here. The absolute fluence of the XFEL pulse has been determined with the help of the calculations utilizing two-photon processes in the argon atom. The high charge states up to +22 observed for Xe in comparison with the calculations point to the occurrence of sequential L-shell multiphoton absorption and of resonance-enabled x-ray multiple ionization.
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6.
  • Tachibana, T., et al. (author)
  • Nanoplasma Formation by High Intensity Hard X-rays
  • 2015
  • In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 5
  • Journal article (peer-reviewed)abstract
    • Using electron spectroscopy, we have investigated nanoplasma formation from noble gas clusters exposed to high-intensity hard-x-ray pulses at similar to 5 keV. Our experiment was carried out at the SPring-8 Angstrom Compact free electron LAser (SACLA) facility in Japan. Dedicated theoretical simulations were performed with the molecular dynamics tool XMDYN. We found that in this unprecedented wavelength regime nanoplasma formation is a highly indirect process. In the argon clusters investigated, nanoplasma is mainly formed through secondary electron cascading initiated by slow Auger electrons. Energy is distributed within the sample entirely through Auger processes and secondary electron cascading following photoabsorption, as in the hard x-ray regime there is no direct energy transfer from the field to the plasma. This plasma formation mechanism is specific to the hard-x-ray regime and may, thus, also be important for XFEL-based molecular imaging studies. In xenon clusters, photo-and Auger electrons contribute more significantly to the nanoplasma formation. Good agreement between experiment and simulations validates our modelling approach. This has wide-ranging implications for our ability to quantitatively predict the behavior of complex molecular systems irradiated by high-intensity hard x-rays.
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7.
  • Fukuzawa, H., et al. (author)
  • Electron spectroscopy of rare-gas clusters irradiated by x-ray free-electron laser pulses from SACLA
  • 2016
  • In: Journal of Physics B-Atomic Molecular and Optical Physics. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 49:3
  • Journal article (peer-reviewed)abstract
    • We have measured electron energy spectra and asymmetry parameters of Ar clusters and Xe clusters illuminated by intense x-rays at 5 and 5.5 keV. A velocity map imaging spectrometer was developed for this purpose and employed at an x-ray free-electron laser facility, SACLA in Japan. The cluster size dependence and the peak fluence dependence of the electron spectra and asymmetry parameters are discussed.
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8.
  • Iablonskyi, D., et al. (author)
  • Interatomic Coulombic Decay Processes after Multiple Valence Excitations in Ne Clusters
  • 2015
  • In: Journal of Physics: Conference Series. - : IOP Publishing. - 1742-6596 .- 1742-6588. ; 635, s. 112067-112067
  • Conference paper (peer-reviewed)abstract
    • We present a comprehensive analysis of autoionization processes in Ne clusters (similar to 5000 atoms) after multiple valence excitations by free electron laser radiation. The evolution from 2-body interatomic Coulombic decay (ICD) to 3-body ICD is demonstrated when changing from surface to bulk Frenkel exciton excitation. Super Coster-Kronig type 2-body ICD is observed at Wannier exciton which quenches the main ICD channel.
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9.
  • Iablonskyi, D., et al. (author)
  • Slow Interatomic Coulombic Decay of Multiply Excited Neon Clusters
  • 2016
  • In: Physical Review Letters. - 0031-9007. ; 117:27
  • Journal article (peer-reviewed)abstract
    • Ne clusters (∼5000 atoms) were resonantly excited (2p→3s) by intense free electron laser (FEL) radiation at FERMI. Such multiply excited clusters can decay nonradiatively via energy exchange between at least two neighboring excited atoms. Benefiting from the precise tunability and narrow bandwidth of seeded FEL radiation, specific sites of the Ne clusters were probed. We found that the relaxation of cluster surface atoms proceeds via a sequence of interatomic or intermolecular Coulombic decay (ICD) processes while ICD of bulk atoms is additionally affected by the surrounding excited medium via inelastic electron scattering. For both cases, cluster excitations relax to atomic states prior to ICD, showing that this kind of ICD is rather slow (picosecond range). Controlling the average number of excitations per cluster via the FEL intensity allows a coarse tuning of the ICD rate.
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10.
  • Ma, R., et al. (author)
  • Photoelectron angular distributions for the two-photon ionization of helium by ultrashort extreme ultraviolet free-electron laser pulses
  • 2013
  • In: Journal of Physics B: Atomic, Molecular and Optical Physics. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 46:16
  • Journal article (peer-reviewed)abstract
    • The two-photon ionization of helium atoms by ultrashort extreme-ultraviolet free-electron laser pulses, produced by the SPring-8 Compact SASE Source test accelerator, was investigated at photon energies of 20.3, 21.3, 23.0 and 24.3 eV. The angular distribution of photoelectrons generated by two-photon ionization is obtained using a velocity map imaging spectrometer. The phase-shift differences and amplitude ratios of the outgoing s and d continuum wave packets are extracted from the photoelectron angular distributions. The obtained values of the phase-shift differences are distinct from scattering phase-shift differences when the photon energy is tuned to a resonance with an excited level or Rydberg manifold. The difference stems from the co-presence of resonant and non-resonant path contributions in the two-photon ionization by femtosecond pulses. Since the relative contribution of both paths can be controlled in principle by the pulse shape, these results illustrate a new way to tailor the continuum wave packet.
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11.
  • Takanashi, T, et al. (author)
  • Time-Resolved Measurement of Interatomic Coulombic Decay Induced by Two-Photon Double Excitation of Ne2
  • 2017
  • In: Physical Review Letters. - 0031-9007. ; 118:3
  • Journal article (peer-reviewed)abstract
    • The hitherto unexplored two-photon doubly excited states [Ne∗(2p-13s)]2 were experimentally identified using the seeded, fully coherent, intense extreme ultraviolet free-electron laser FERMI. These states undergo ultrafast interatomic Coulombic decay (ICD), which predominantly produces singly ionized dimers. In order to obtain the rate of ICD, the resulting yield of Ne2+ ions was recorded as a function of delay between the extreme ultraviolet pump and UV probe laser pulses. The extracted lifetimes of the long-lived doubly excited states, 390(-130/+450) fs, and of the short-lived ones, less than 150 fs, are in good agreement with ab initio quantum mechanical calculations.
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12.
  • Gryzlova, E. V., et al. (author)
  • Doubly resonant three-photon double ionization of Ar atoms induced by an EUV free-electron laser
  • 2011
  • In: Physical Review A (Atomic, Molecular and Optical Physics). - 1050-2947. ; 84:6
  • Journal article (peer-reviewed)abstract
    • A mechanism for three-photon double ionization of atoms by extreme-ultraviolet free-electron laser pulses is revealed, where in a sequential process the second ionization step, proceeding via resonant two-photon ionization of ions, is strongly enhanced by the excitation of ionic autoionizing states. In contrast to the conventional model, the mechanism explains the observed relative intensities of photoelectron peaks and their angular dependence in three-photon double ionization of argon.
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13.
  • Gryzlova, E. V., et al. (author)
  • Influence of an atomic resonance on the coherent control of the photoionization process
  • 2022
  • In: Physical Review Research. - 2643-1564. ; 4:3
  • Journal article (peer-reviewed)abstract
    • In coherent control schemes, pathways connecting an initial and a final state can be independently controlled by manipulating the complex amplitudes of their transition matrix elements. For paths characterized by the absorption of multiple photons, these quantities depend on the magnitude and phase between the intermediate steps, and are expected to be strongly affected by the presence of resonances. We investigate the coherent control of the photoemission process in neon using a phase-controlled two-color extreme ultraviolet pulse with frequency in proximity of an excited energy state. Using helium as a reference, we show that the presence of such a resonance in neon modifies the amplitude and phase of the asymmetric emission of photoelectrons. Theoretical simulations based on perturbation theory are in fair agreement with the experimental observations.
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14.
  • Mondal, S., et al. (author)
  • Photoelectron angular distributions for the two-photon sequential double ionization of xenon by ultrashort extreme ultraviolet free electron laser pulses
  • 2013
  • In: Journal of Physics B: Atomic, Molecular and Optical Physics. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 46:16
  • Journal article (peer-reviewed)abstract
    • Xenon atoms are double-ionized by sequential two-photon absorption by ultrashort extreme ultraviolet free-electron laser pulses with a photon energy of 23.0 and 24.3 eV, produced by the SPring-8 Compact SASE Source test accelerator. The angular distributions of photoelectrons generated by two-photon double ionization are obtained using velocity map imaging. The results are reproduced reasonably well by the present theoretical calculations within the multi-configurational Dirac-Fock approach.
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15.
  • Went, M, et al. (author)
  • Author Correction: Identification of multiple risk loci and regulatory mechanisms influencing susceptibility to multiple myeloma
  • 2019
  • In: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 10:1, s. 213-
  • Journal article (peer-reviewed)abstract
    • The original version of this Article contained an error in the spelling of a member of the PRACTICAL Consortium, Manuela Gago-Dominguez, which was incorrectly given as Manuela Gago Dominguez. This has now been corrected in both the PDF and HTML versions of the Article. Furthermore, in the original HTML version of this Article, the order of authors within the author list was incorrect. The PRACTICAL consortium was incorrectly listed after Richard S. Houlston and should have been listed after Nora Pashayan. This error has been corrected in the HTML version of the Article; the PDF version was correct at the time of publication.
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17.
  • Kukk, E., et al. (author)
  • Formative period in the x-ray-induced photodissociation of organic molecules
  • 2021
  • In: Physical Review Research. - 2643-1564. ; 3:1
  • Journal article (peer-reviewed)abstract
    • Absorption of x-ray photons by atomic inner shells of light-element organics and biomolecules often leads to formation of dicationic electronic states and to molecular fragmentation. We investigated the x-ray-induced dissociation landscape of a representative medium-sized organic molecule, thiophene, by femtosecond x-ray pulses from the Super Photon Ring-8 GeV (SPring-8) Angstrom Compact Free-Electron Laser (SACLA). Holes, created in the sulfur 2p orbital by photoemission, were filled by the Auger process that created dicationic molecular states within a broad range of internal energies—a starting point particular to x-ray-induced dynamics. The evolution of the ionized molecules was monitored by a pump-probe experiment using a near-infrared (800 nm) laser pulse. Ion-ion coincidence and ion momentum analysis reveals enhanced yields of ionic fragments from multibody breakup of the ring, attributed to additional ionization of the highly excited fraction of the dicationic parent molecular states. The transient nature of the enhancement and its decay with about a 160-fs time constant indicate formation of an open-ring parent geometry and the statistical survival time of the parent species before the dissociation events. By probing specific Auger final states of transient, highly excited nature by near-infrared light, we demonstrate how pump-probe signatures can be related to the key features in dynamics during the early period of the x-ray-induced damage of organic molecules and biomolecules.
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18.
  • Sodergren, S. C., et al. (author)
  • International Validation of the EORTC QLQ-ANL27, a Field Study to Test the Anal Cancer–Specific Health-Related Quality of Life Questionnaire
  • 2023
  • In: International Journal of Radiation Oncology Biology Physics. - : Elsevier BV. - 0360-3016. ; 115:5, s. 1155-1164
  • Journal article (peer-reviewed)abstract
    • Purpose: The European Organisation for Research and Treatment of Cancer (EORTC) health-related quality of life questionnaire for anal cancer (QLQ-ANL27) supplements the EORTC cancer generic measure (QLQ-C30) to measure concerns specific to people with anal cancer treated with chemoradiotherapy. This study tested the psychometric properties and acceptability of the QLQ-ANL27. Methods and Materials: People with anal cancer were recruited from 15 countries to complete the QLQ-C30 and QLQ-ANL27 and provide feedback on the QLQ-ANL27. Item responses, scale structure (multitrait scaling, factor analysis), reliability (internal consistency and reproducibility) and sensitivity (known group comparisons and responsiveness to change) of the QLQ-ANL27 were evaluated. Results: Data from 382 people were included in the analyses. The EORTC QLQ-ANL27 was acceptable, comprehensive, and easy to complete, taking an average 8 minutes to complete. Psychometric analyses supported the EORTC QLQ-ANL27 items and reliability (Cronbach's α ranging from 0.71-0.93 and test-retest coefficients above 0.7) and validity of the scales (particularly nonstoma bowel symptoms and pain/discomfort). Most scales distinguished people according to treatment phase and performance status. Bowel (nonstoma), pain/discomfort, and vaginal symptoms were sensitive to deteriorations over time. The stoma-related scales remained untested because of low numbers of people with a stoma. Revisions to the scoring and question ordering of the sexual items were proposed. Conclusions: The QLQ-ANL27 has good psychometric properties and is available in 16 languages for people treated with chemoradiotherapy for anal cancer. It is used in clinical trials and has a potential role in clinical practice.
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19.
  • Went, M, et al. (author)
  • Identification of multiple risk loci and regulatory mechanisms influencing susceptibility to multiple myeloma
  • 2018
  • In: Nature communications. - : Springer Science and Business Media LLC. - 2041-1723. ; 9:1, s. 3707-
  • Journal article (peer-reviewed)abstract
    • Genome-wide association studies (GWAS) have transformed our understanding of susceptibility to multiple myeloma (MM), but much of the heritability remains unexplained. We report a new GWAS, a meta-analysis with previous GWAS and a replication series, totalling 9974 MM cases and 247,556 controls of European ancestry. Collectively, these data provide evidence for six new MM risk loci, bringing the total number to 23. Integration of information from gene expression, epigenetic profiling and in situ Hi-C data for the 23 risk loci implicate disruption of developmental transcriptional regulators as a basis of MM susceptibility, compatible with altered B-cell differentiation as a key mechanism. Dysregulation of autophagy/apoptosis and cell cycle signalling feature as recurrently perturbed pathways. Our findings provide further insight into the biological basis of MM.
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20.
  • Ali, S. K. Imran, et al. (author)
  • Hydrothermal Synthesis of the Oxofluoride FeSbO2F2-An Anti-ferromagnetic Spin S=5/2 Compound
  • 2017
  • In: Inorganic Chemistry. - : American Chemical Society (ACS). - 0020-1669 .- 1520-510X. ; 56:8, s. 4662-4667
  • Journal article (peer-reviewed)abstract
    • The new oxofluoride compound FeSbO2F2 was synthesized by hydro thermal techniques at 230 degrees C. Its crystal structure was determined from single-crystal Xray diffraction data. The compound crystallizes in the monoclinic space group C2/c with one crystallographic site for Fe3+ and SP3+, respectively. The crystal structure is made of [FeO2F4] octahedra and seesaw [SbO4] building blocks. These are connected to form [FeO2F2] layers and [SbO2] chains that bond together via the oxygen atoms to form the three-dimensional framework structure. Magnetic susceptibility and heat capacity measurements indicate long-range anti-ferromagnetic ordering below a Neel temperature of similar to 175 K Two-dimensional anti-ferromagnetic short-range order in the square planar net of the Fe3+ cations extends to temperatures far above the Neel temperature.
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22.
  • Berman, F., et al. (author)
  • New grid scheduling and rescheduling methods in the GrADS Project
  • 2005
  • In: International journal of parallel programming. - : Springer Science and Business Media LLC. - 0885-7458 .- 1573-7640. ; 33:3-Feb, s. 209-229
  • Journal article (peer-reviewed)abstract
    • The goal of the Grid Application Development Software (GrADS) Project is to provide programming tools and an execution environment to ease program development for the Grid. This paper presents recent extensions to the GrADS software framework: a new approach to scheduling workflow computations, applied to a 3-D image reconstruction application; a simple stop/migrate/restart approach to rescheduling Grid applications, applied to a QR factorization benchmark; and a process-swapping approach to rescheduling, applied to an N-body simulation. Experiments validating these methods were carried out on both the GrADS MacroGrid (a small but functional Grid) and the MicroGrid (a controlled emulation of the Grid).
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23.
  • Berman, F., et al. (author)
  • The GrADS project : Software support for high-level grid application development
  • 2001
  • In: The international journal of high performance computing applications. - : SAGE Publications. - 1094-3420 .- 1741-2846. ; 15:4, s. 327-344
  • Journal article (peer-reviewed)abstract
    • Advances in networking technologies will soon make it possible to use the global information infrastructure in a qualitatively different way-as a computational as well as an information resource. As described in the recent book The Grid: Blueprint for a New Computing Infrastructure, this Grid will connect the nation's computers, databases, instruments, and people in a seamless web of computing and distributed intelligence, which can be used in an on demand fashion as a problem-solving resource in many fields of human endeavor-and, in particular, science and engineering. The availability of grid resources will give rise to dramatically new classes of applications, in which computing resources are no longer localized but, rather, distributed, heterogeneous, and dynamic; computation is increasingly sophisticated and multidisciplinary; and computation is integrated into our daily lives and, hence, subject to stricter time constraints than at present. The impact of these new applications will be pervasive, ranging from new systems for scientific inquiry, through computing support for crisis management, to the use of ambient computing to enhance personal mobile computing environments. To realize this vision, significant scientific and technical obstacles must be overcome. Principal among these is usability. The goal of the Grid Application Development Software (GrADS) project is to simplify distributed heterogeneous computing in the same way that the World Wide Web simplified information sharing over the Internet. To that end, the project is exploring the scientific and technical problems that must be solved to make it easier for ordinary scientific users to develop, execute, and tune applications on the Grid. In this paper, the authors describe the vision and strategies underlying the GrADS project, including the base software architecture for grid execution and performance monitoring, strategies and tools for construction of applications from libraries of grid-aware components, and development of innovative new science and engineering applications that can exploit these new technologies to run effectively in grid environments.
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26.
  • Cooper, K., et al. (author)
  • New Grid Scheduling and Rescheduling Methods in the GrADS Project
  • 2004
  • Conference paper (peer-reviewed)abstract
    • Summary form only given. The goal of the Grid Application Development Software (GrADS) project is to provide programming tools and an execution environment to ease program development for the grid. We present recent extensions to the GrADS software framework: 1. A new approach to scheduling workflow computations, applied to a 3D image reconstruction application; 2. A simple stop/migrate/restart approach to rescheduling grid applications, applied to a QR 3. A process-swapping approach to rescheduling, applied to an N-body simulation. Experiments validating these methods were carried out on both the GrADS MacroGrid (a small but functional grid) and the MicroGrid (a controlled emulation of the grid) and the results were demonstrated at the SC2003 conference.
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27.
  • Cowie, A. L., et al. (author)
  • Applying a science-based systems perspective to dispel misconceptions about climate effects of forest bioenergy
  • 2021
  • In: Global Change Biology Bioenergy. - : John Wiley and Sons Inc. - 1757-1693 .- 1757-1707. ; 13:8, s. 1210-1231
  • Journal article (peer-reviewed)abstract
    • The scientific literature contains contrasting findings about the climate effects of forest bioenergy, partly due to the wide diversity of bioenergy systems and associated contexts, but also due to differences in assessment methods. The climate effects of bioenergy must be accurately assessed to inform policy-making, but the complexity of bioenergy systems and associated land, industry and energy systems raises challenges for assessment. We examine misconceptions about climate effects of forest bioenergy and discuss important considerations in assessing these effects and devising measures to incentivize sustainable bioenergy as a component of climate policy. The temporal and spatial system boundary and the reference (counterfactual) scenarios are key methodology choices that strongly influence results. Focussing on carbon balances of individual forest stands and comparing emissions at the point of combustion neglect system-level interactions that influence the climate effects of forest bioenergy. We highlight the need for a systems approach, in assessing options and developing policy for forest bioenergy that: (1) considers the whole life cycle of bioenergy systems, including effects of the associated forest management and harvesting on landscape carbon balances; (2) identifies how forest bioenergy can best be deployed to support energy system transformation required to achieve climate goals; and (3) incentivizes those forest bioenergy systems that augment the mitigation value of the forest sector as a whole. Emphasis on short-term emissions reduction targets can lead to decisions that make medium- to long-term climate goals more difficult to achieve. The most important climate change mitigation measure is the transformation of energy, industry and transport systems so that fossil carbon remains underground. Narrow perspectives obscure the significant role that bioenergy can play by displacing fossil fuels now, and supporting energy system transition. Greater transparency and consistency is needed in greenhouse gas reporting and accounting related to bioenergy. 
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28.
  • Cucherousset, J., et al. (author)
  • Growth-enhanced salmon modify stream ecosystem functioning
  • 2021
  • In: Journal of Fish Biology. - : Wiley. - 0022-1112 .- 1095-8649. ; 99:6, s. 1978-1989
  • Journal article (peer-reviewed)abstract
    • Use of fast-growing domesticated and/or genetically modified strains of fish is becoming increasingly common in aquaculture, increasing the likelihood of deliberate or accidental introductions into the wild. To date, their ecological impacts on ecosystems remain to be quantified. Here, using a controlled phenotype manipulation by implanting growth hormone in juvenile Atlantic salmon (Salmo salar), we found that growth-enhanced fish display changes in several phenotypic traits known to be important for ecosystem functioning, such as habitat use, morphology and excretion rate. Furthermore, these phenotypic changes were associated with significant impacts on the invertebrate community and key stream ecosystem functions such as primary production and leaf-litter decomposition. These findings provide novel evidence that introductions of growth-enhanced fish into the wild can affect the functioning of natural ecosystems and represent a form of intraspecific invasion. Consequently, environmental impact assessments of growth-enhanced organisms need to explicitly consider ecosystem-level effects.
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29.
  • Djane, N K, et al. (author)
  • Chromium speciation in natural waters using serially connected supported liquid membranes.
  • 1999
  • In: Talanta. - 1873-3573. ; 48:5, s. 1121-1132
  • Journal article (peer-reviewed)abstract
    • A supported liquid membrane (SLM) method for the speciation of chromium has been developed. The method is based on selective extraction and enrichment of anionic Cr(VI) and cationic Cr(III) species in two serially connected SLM units. Methyltricaprylammonium chloride (Aliquat) and di-(2-ethylhexyl) phosphoric acid (DEHPA), respectively were used as the selective extractants in the membrane liquid. Graphite furnace atomic absorption spectrometry (GFAAS) was utilised for final determination. Optimised conditions for the DEHPA membrane were, sample solution at pH 3, acceptor solution 0.1 M HNO(3) and 10% w/w carrier in kerosene. The corresponding values for the Aliquat membrane were pH 7, 0.75 M HNO(3) and 6% w/w carrier in di-n-hexylether. This gave extraction efficiencies for Cr(III) and Cr(VI) of 90 and 40%, respectively. The method was used to measure the concentration of Cr III and Cr VI in surface water from an abandoned tannery site. Storage experiments at different pH showed that preservation at neutral pH gave almost constant values over a period of one month. At acidic pH (pH=3.0) the concentration of Cr(VI) decreased rapidly while the concentration of Cr(III) increased. The detection limit, expressed as three times the standard deviation of enriched blank samples was 0.01 mug l(-1).
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30.
  • Gademann, G., et al. (author)
  • Attosecond control of electron-ion recollision in high harmonic generation
  • 2011
  • In: New Journal of Physics. - : IOP Publishing. - 1367-2630. ; 13
  • Journal article (peer-reviewed)abstract
    • We show that high harmonic generation driven by an intense near-infrared (IR) laser can be temporally controlled when an attosecond pulse train (APT) is used to ionize the generation medium, thereby replacing tunnel ionization as the first step in the well-known three-step model. New harmonics are formed when the ionization occurs at a well-defined time within the optical cycle of the IR field. The use of APT-created electron wave packets affords new avenues for the study and application of harmonic generation. In the present experiment, this makes it possible to study harmonic generation at IR intensities where tunnel ionization does not give a measurable signal.
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32.
  • Heyl, C. M., et al. (author)
  • High-average power high-harmonic and attosecond sources : Status and prospects
  • 2016
  • In: Compact EUV and X-ray Light Sources, EUVXRAY 2016. - 9781943580095 ; Part F14-EUVXRAY 2016
  • Conference paper (peer-reviewed)abstract
    • Experiments employing extreme ultraviolet sources based on high harmonic generation often suffer from photon flux limitations. We discuss current status and prospects for scaling such sources to higher repetition rate, pulse energy and average power.
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39.
  • Kennedy, K., et al. (author)
  • Telescoping languages : A strategy for automatic generation of scientific problem-solving systems from annotated libraries
  • 2001
  • In: Journal of Parallel and Distributed Computing. - : Elsevier BV. - 0743-7315 .- 1096-0848. ; 61:12, s. 1803-1826
  • Journal article (peer-reviewed)abstract
    • As machines and programs have become more complex., the process of programming applications that can exploit the power of high-performance systems has become more difficult and correspondingly more labor-intensive. This has substantially widened the software gap the discrepancy between the need for new software and the aggregate capacity of the workforce to produce it. This problem has been compounded by the slow growth of programming productivity, especially for high-performance programs, over the past two decades. One way to bridge this gap is to make it possible for end users to develop programs in high-level domain-specific programming systems. In the past, a major impediment to the acceptance of such systems has been the poor performance of the resulting applications. To address this problem, we are developing a new compiler-based infrastructure, called TeleGen, that will make it practical to construct efficient domain-specific high-level languages from annotated component libraries. We call these languages telescoping languages, because they can be nested within one another. For programs written in telescoping languages. high performance and reasonable compilation times can be achieved by exhaustively analyzing the component libraries in advance to produce a language processor that recognizes and optimizes library operations as primitives in the language. The key to making this strategy practical is to keep compile times low by generating a custom compiler with extensive built-in knowledge of the underlying libraries. The goal is to achieve compile times that tire linearly proportional to the size of the program presented by the user. rather than to the aggregate size of that program plus the base libraries.
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41.
  • Kornilov, O., et al. (author)
  • Coulomb explosion of diatomic molecules in intense XUV fields mapped by partial covariance
  • 2013
  • In: Journal of Physics B: Atomic, Molecular and Optical Physics. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 46:16
  • Journal article (peer-reviewed)abstract
    • Single-shot time-of-flight spectra for Coulomb explosion of N-2 and I-2 molecules have been recorded at the Free Electron LASer in Hamburg (FLASH) and have been analysed using a partial covariance mapping technique. The partial covariance analysis unravels a detailed picture of all significant Coulomb explosion pathways, extending up to the N4+-N5+ channel for nitrogen and up to the I8+-I9+ channel for iodine. The observation of the latter channel is unexpected if only sequential ionization processes from the ground state ions are considered. The maximum kinetic energy release extracted from the covariance maps for each dissociation channel shows that Coulomb explosion of nitrogen molecules proceeds much faster than that of the iodine. The N-2 ionization dynamics is modelled using classical trajectory simulations in good agreement with the outcome of the experiments. The results suggest that covariance mapping of the Coulomb explosion can be used to measure the intensity and pulse duration of free-electron lasers.
  •  
42.
  • Kovács, K, et al. (author)
  • Multi-parameter optimization of a loose focusing high flux high-harmonic beamline
  • 2019
  • In: Journal of Physics B: Atomic, Molecular and Optical Physics. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 52:5, s. 055402-055402
  • Journal article (peer-reviewed)abstract
    • We perform a multi-dimensional parameter scan in the generation of high-order harmonics, with the main purpose to find the macroscopic conditions that optimize the harmonic yield in a specific spectral domain, around 40 eV for this particular case. The scanned parameters are the laser pulse energy, gas pressure, interaction cell position relative to focus and the cell length, while the fixed parameters are chosen to model a loose focusing configuration which is used in many existing laboratories. We performed the simulations with a 3D non-adiabatic model complemented by a detailed analysis of the phase matching mechanisms involved in an efficient harmonic generation. Based on the results we identify a range of parameter combinations that lead to a high yield in the specified spectral domain. The method and results presented here can be the framework for the design and construction of high flux high-order harmonic generation beamlines.
  •  
43.
  •  
44.
  • L'Huillier, A., et al. (author)
  • Atomic physics with attosecond pulses
  • 2006
  • In: International Conference on Ultrafast Phenomena, UP 2006. - 1557528101 - 9781557528100
  • Conference paper (peer-reviewed)
  •  
45.
  •  
46.
  • Major, B., et al. (author)
  • Macroscopic Optimization of High Harmonic Generation for High Power Laser Pulses
  • 2016
  • In: High Intensity Lasers and High Field Phenomena, HILAS 2016. - 9781943580095 ; Part F15-HILAS 2016
  • Conference paper (peer-reviewed)abstract
    • We study upscaling of gas high harmonic generation, to make efficient use of the ever increasing laser pulse powers. Loose focusing geometries optimizing phasematching are investigated and compared in HHG efficiency to shorter focusing arrangements.
  •  
47.
  • Mazzetti, M.J., et al. (author)
  • NORDICCS CCS roadmap
  • 2014
  • In: Energy Procedia. - : Elsevier BV. - 1876-6102. ; 51, s. 1-13
  • Conference paper (peer-reviewed)abstract
    • The Nordic CCS roadmap is developed in the NORDICCS project, a collaborative research project between leading CCS research institutions in the five Nordic countries. The roadmap will outline jointly developed Nordic strategies for widespread implementation of CCS in the Nordic countries in order to help Nordic industries meet a carbon constrained future with a high price on carbon emissions. It will identify pathways and milestones for large-scale Nordic implementation of CCS resulting in beneficial economies of scale that will increase the likelihood of implementation. Several novel cases will be presented that reveal future Nordic opportunities, including industrial CCS where emitters have large point sources of CO2 localized in clusters, and natural gas sweetening with the potential for use of Enhanced Oil Recovery (EOR) to defray the costs. Recommendations will be made for actions relating to joint political work in the Nordic region for improving the framework conditions for CCS.
  •  
48.
  • Oberst, J., et al. (author)
  • Planetary polar explorer – the case for a next-generation remote sensing mission to low Mars orbit
  • 2022
  • In: Experimental Astronomy. - : Springer Science and Business Media LLC. - 0922-6435 .- 1572-9508. ; 54, s. 695-711
  • Journal article (peer-reviewed)abstract
    • We propose the exploration of polar areas on Mars by a next-generation orbiter mission. In particular, we aim at studying the seasonal and regional variations in snow-deposits, which – in combination with measurements of temporal variations in rotation and gravity field – will improve models of the global planetary CO2 cycle. A monitoring of polar scarps for rock falls and avalanche events may provide insights into the dynamics of ice sheets. The mapping of the complex layering of polar deposits, believed to contain an important record of climate history, may help us understand the early climate collapse on the planet. Hence, we propose an innovative next-generation exploration mission in polar circular Low Mars Orbit, which will be of interest to scientists and challenging to engineers alike. Schemes will be developed to overcome atmosphere drag forces acting upon the spacecraft by an electric propulsion system. Based on the experience of missions of similar type in Earth orbit we believe that a two-year mission in circular orbit is possible at altitudes as low as 150 km. Such a mission opens new opportunities for novel remote sensing approaches, not requiring excessive telescope equipment or power. We anticipate precision altimetry, powerful radars, high-resolution imaging, and magnetic field mapping. © 2022, The Author(s).
  •  
49.
  •  
50.
  • Sanchez-Gonzalez, A., et al. (author)
  • Auger electron and photoabsorption spectra of glycine in the vicinity of the oxygen K-edge measured with an X-FEL
  • 2015
  • In: Journal of Physics B-Atomic Molecular and Optical Physics. - : IOP Publishing. - 0953-4075 .- 1361-6455. ; 48:23
  • Journal article (peer-reviewed)abstract
    • We report the first measurement of the near oxygen K-edge auger spectrum of the glycine molecule. Our work employed an x-ray free electron laser as the photon source operated with input photon energies tunable between 527 and 547 eV. Complete electron spectra were recorded at each photon energy in the tuning range, revealing resonant and non-resonant auger structures. Finally ab initio theoretical predictions are compared with the measured above the edge auger spectrum and an assignment of auger decay channels is performed.
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