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- Aamodt, K., et al.
(författare)
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The ALICE experiment at the CERN LHC
- 2008
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Ingår i: Journal of Instrumentation. - 1748-0221. ; 3:S08002
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Forskningsöversikt (refereegranskat)abstract
- ALICE (A Large Ion Collider Experiment) is a general-purpose, heavy-ion detector at the CERN LHC which focuses on QCD, the strong-interaction sector of the Standard Model. It is designed to address the physics of strongly interacting matter and the quark-gluon plasma at extreme values of energy density and temperature in nucleus-nucleus collisions. Besides running with Pb ions, the physics programme includes collisions with lighter ions, lower energy running and dedicated proton-nucleus runs. ALICE will also take data with proton beams at the top LHC energy to collect reference data for the heavy-ion programme and to address several QCD topics for which ALICE is complementary to the other LHC detectors. The ALICE detector has been built by a collaboration including currently over 1000 physicists and engineers from 105 Institutes in 30 countries, Its overall dimensions are 16 x 16 x 26 m(3) with a total weight of approximately 10 000 t. The experiment consists of 18 different detector systems each with its own specific technology choice and design constraints, driven both by the physics requirements and the experimental conditions expected at LHC. The most stringent design constraint is to cope with the extreme particle multiplicity anticipated in central Pb-Pb collisions. The different subsystems were optimized to provide high-momentum resolution as well as excellent Particle Identification (PID) over a broad range in momentum, up to the highest multiplicities predicted for LHC. This will allow for comprehensive studies of hadrons, electrons, muons, and photons produced in the collision of heavy nuclei. Most detector systems are scheduled to be installed and ready for data taking by mid-2008 when the LHC is scheduled to start operation, with the exception of parts of the Photon Spectrometer (PHOS), Transition Radiation Detector (TRD) and Electro Magnetic Calorimeter (EMCal). These detectors will be completed for the high-luminosity ion run expected in 2010. This paper describes in detail the detector components as installed for the first data taking in the summer of 2008.
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| 2. |
- Andrew, P, et al.
(författare)
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Outer divertor target deposited layers during reversed magnetic field operation in JET
- 2005
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Ingår i: Journal of Nuclear Materials. - : Elsevier BV. - 0022-3115 .- 1873-4820. ; 337:1-3, s. 99-103
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Tidskriftsartikel (refereegranskat)abstract
- Divertor surface temperatures are significantly affected by the presence of deposited surface layers. This phenomenon can be used to monitor deposited layer evolution on a shot-by-shot basis. It was found that during an experimental campaign where the B x del B direction was reversed that the outer target, normally an erosion zone, became a deposition zone.
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| 3. |
- Hallquist, Mattias, 1969, et al.
(författare)
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The formation, properties and impact of secondary organic aerosol: Current and emerging issues
- 2009
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Ingår i: Atmospheric Chemistry and Physics. - : Copernicus GmbH. - 1680-7316 .- 1680-7324. ; 9:14, s. 5155-5236
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Tidskriftsartikel (refereegranskat)abstract
- Secondary organic aerosol (SOA) accounts for a significant fraction of ambient tropospheric aerosol and a detailed knowledge of the formation, properties and transformation of SOA is therefore required to evaluate its impact on atmospheric processes, climate and human health. The chemical and physical processes associated with SOA formation are complex and varied, and, despite considerable progress in recent years, a quantitative and predictive understanding of SOA formation does not exist and therefore represents a major research challenge in atmospheric science. This review begins with an update on the current state of knowledge on the global SOA budget and is followed by an overview of the atmospheric degradation mechanisms for SOA precursors, gas-particle partitioning theory and the analytical techniques used to determine the chemical composition of SOA. A survey of recent laboratory, field and modeling studies is also presented. The following topical and emerging issues are highlighted and discussed in detail: molecular characterization of biogenic SOA constituents, condensed phase reactions and oligomerization, the interaction of atmospheric organic components with sulfuric acid, the chemical and photochemical processing of organics in the atmospheric aqueous phase, aerosol formation from real plant emissions, interaction of atmospheric organic components with water, thermodynamics and mixtures in atmospheric models. Finally, the major challenges ahead in laboratory, field and modeling studies of SOA are discussed and recommendations for future research directions are proposed.
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| 6. |
- Graham, Ian, et al.
(författare)
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European guidelines on cardiovascular disease prevention in clinical practice: full text. Fourth Joint Task Force of the European Society of Cardiology and other societies on cardiovascular disease prevention in clinical practice (constituted by representatives of nine societies and by invited experts).
- 2007
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Ingår i: European journal of cardiovascular prevention and rehabilitation : official journal of the European Society of Cardiology, Working Groups on Epidemiology & Prevention and Cardiac Rehabilitation and Exercise Physiology. - : Oxford University Press (OUP). - 1741-8267. ; 14 Suppl 2
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Tidskriftsartikel (refereegranskat)abstract
- Other experts who contributed to parts of the guidelines: Edmond Walma, Tony Fitzgerald, Marie Therese Cooney, Alexandra Dudina European Society of Cardiology (ESC) Committee for Practice Guidelines (CPG): Alec Vahanian (Chairperson), John Camm, Raffaele De Caterina, Veronica Dean, Kenneth Dickstein, Christian Funck-Brentano, Gerasimos Filippatos, Irene Hellemans, Steen Dalby Kristensen, Keith McGregor, Udo Sechtem, Sigmund Silber, Michal Tendera, Petr Widimsky, Jose Luis Zamorano Document reviewers: Irene Hellemans (CPG Review Co-ordinator), Attila Altiner, Enzo Bonora, Paul N. Durrington, Robert Fagard, Simona Giampaoli, Harry Hemingway, Jan Hakansson, Sverre Erik Kjeldsen, Mogens Lytken Larsen, Giuseppe Mancia, Athanasios J. Manolis, Kristina Orth-Gomer, Terje Pedersen, Mike Rayner, Lars Ryden, Mario Sammut, Neil Schneiderman, Anton F. Stalenhoef, Lale Tokgözoglu, Olov Wiklund, Antonis Zampelas
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| 7. |
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| 8. |
- Krivov, A. V., et al.
(författare)
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Can gas in young debris disks be constrained by their radial brightness profiles?
- 2009
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Ingår i: Astronomy and Astrophysics. - : EDP Sciences. - 0004-6361 .- 1432-0746. ; 507:3, s. 1503-1516
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Tidskriftsartikel (refereegranskat)abstract
- Disks around young stars are known to evolve from optically thick, gas-dominated protoplanetary disks to optically thin, almost gas-free debris disks. It is thought that the primordial gas is largely removed at ages of ~10 Myr and indeed, only little amounts of gas have been deduced from observations for debris disks at ages of ⪆10 Myr. However, gas detections are difficult and often indirect, not allowing one to discern the true gas densities. This suggests using dynamical arguments: it has been argued that gas, if present with higher densities, would lead to flatter radial profiles of the dust density and brightness than those actually observed. In this paper, we systematically study the influence of gas on the radial profiles of brightness. We assume that dust is replenished by planetesimals orbiting in a “birth ring” and model the dust distribution and scattered-light brightness profile in the outer part of the disk exterior to the birth ring, under different assumptions about the gas component. Our numerical simulations, supported with an analytic model, show that the radial profile of dust density and the surface brightness are surprisingly insensitive to variation of the parameters of a central star, location of the dust-producing planetesimal belt, dustiness of the disk and - most importantly - the parameters of the ambient gas. The radial brightness slopes in the outer disks are all typically in the range -3...-4. This result holds for a wide range of gas densities (three orders of magnitude), for different radial profiles of the gas temperature, both for gas of solar composition and gas of strongly non-solar composition. The slopes of -3...-4 we find are the same that were theoretically found for gas-free debris disks, and they are the same as actually retrieved from observations of many debris disks. Our specific results for three young (10-30 Myr old), spatially resolved, edge-on debris disks (β Pic, HD 32297, and AU Mic) show that the observed radial profiles of the surface brightness do not pose any stringent constraints on the gas component of the disk. We cannot exclude that outer parts of the systems may have retained substantial amounts of primordial gas which is not evident in the gas observations (e.g. as much as 50 Earth masses for β Pic). However, the possibility that gas, most likely secondary, is only present in little to moderate amounts, as deduced from gas detections (e.g. ~0.05 Earth masses in the β Pic disk or even less), remains open, too.
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| 9. |
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| 10. |
- Scolari, Silvia, et al.
(författare)
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Lateral distribution of the transmembrane domain of influenza virus hemagglutinin revealed by time-resolved fluorescence imaging.
- 2009
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Ingår i: Journal of Biological Chemistry. - 0021-9258 .- 1083-351X. ; 284:23, s. 15708-16
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Tidskriftsartikel (refereegranskat)abstract
- Influenza virus hemagglutinin (HA) has been suggested to be enriched in liquid-ordered lipid domains named rafts, which represent an important step in virus assembly. We employed Förster resonance energy transfer (FRET) via fluorescence lifetime imaging microscopy to study the interaction of the cytoplasmic and transmembrane domain (TMD) of HA with agly co sylphos pha tidyl ino si tol (GPI)-anchored peptide, an established marker for rafts in the exoplasmic leaflet of living mammalian plasma membranes. Cyan fluorescent protein (CFP) was fused to GPI, whereas the HA sequence was tagged with yellow fluorescent protein (YFP) on its exoplasmic site (TMD-HA-YFP), avoiding any interference of fluorescent proteins with the proposed role of the cytoplasmic domain in lateral organization of HA. Constructs were expressed in Chinese hamster ovary cells (CHO-K1) for which cholesterol-sensitive lipid nanodomains and their dimension in the plasma membrane have been described (Sharma, P., Varma, R., Sarasij, R. C., Ira, Gousset, K., Krishnamoorthy, G., Rao, M., and Mayor, S. (2004) Cell 116, 577-589). Upon transfection in CHO-K1 cells, TMD-HA-YFP is partially expressed as a dimer. Only dimers are targeted to the plasma membrane. Clustering of TMD-HA-YFP with GPI-CFP was observed and shown to be reduced upon cholesterol depletion, a treatment known to disrupt rafts. No indication for association of TMD-HA-YFP with GPI-CFP was found when palmitoylation, an important determinant of raft targeting, was suppressed. Clustering of TMD-HA-YFP and GPI-CFP was also observed in purified plasma membrane suspensions by homoFRET. We concluded that the pal mit oy lated TMD-HA alone is sufficient to recruit HA to cholesterol-sensitive nanodomains. The corresponding construct of the spike protein E2 of Semliki Forest virus did not partition preferentially in such domains.
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