| 1. |
- Meyer, H., et al.
(författare)
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Overview of physics results from MAST
- 2009
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Ingår i: Nuclear Fusion. - : IOP Publishing. - 0029-5515 .- 1741-4326. ; 49:10, s. 104017-
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Tidskriftsartikel (refereegranskat)abstract
- Several improvements to the MAST plant and diagnostics have facilitated new studies advancing the physics basis for ITER and DEMO, as well as for future spherical tokamaks (STs). Using the increased heating capabilities P-NBI <= 3.8 MW H-mode at I-P = 1.2 MA was accessed showing that the energy confinement on MAST scales more weakly with I-P and more strongly with B-t than in the ITER IPB98(y, 2) scaling. Measurements of the fuel retention of shallow pellets extrapolate to an ITER particle throughput of 70% of its original designed total throughput capacity. The anomalous momentum diffusion, chi(phi), is linked to the ion diffusion, chi(i), with a Prandtl number close to P-phi approximate to chi(phi)/chi(i) approximate to 1, although chi(i) approaches neoclassical values. New high spatial resolution measurements of the edge radial electric field, E-r, show that the position of steepest gradients in electron pressure and E-r (i.e. shearing rate) are coincident, but their magnitudes are not linked. The T-e pedestal width on MAST scales with root beta(ped)(pol) rather than rho(pol). The edge localized mode (ELM) frequency for type-IV ELMs, new in MAST, was almost doubled using n = 2 resonant magnetic perturbations from a set of four external coils (n = 1, 2). A new internal 12 coil set (n <= 3) has been commissioned. The filaments in the inter-ELM and L-mode phase are different from ELM filaments, and the characteristics in L-mode agree well with turbulence calculations. A variety of fast particle driven instabilities were studied from 10 kHz saturated fishbone like activity up to 3.8 MHz compressional Alfven eigenmodes. Fast particle instabilities also affect the off-axis NBI current drive, leading to fast ion diffusion of the order of 0.5 m(2) s(-1) and a reduction in the driven current fraction from 40% to 30%. EBW current drive start-up is demonstrated for the first time in a ST generating plasma currents up to 55 kA. Many of these studies contributed to the physics basis of a planned upgrade to MAST.
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| 2. |
- Clark, Andrew G., et al.
(författare)
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Evolution of genes and genomes on the Drosophila phylogeny
- 2007
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Ingår i: Nature. - : Springer Science and Business Media LLC. - 0028-0836 .- 1476-4687. ; 450:7167, s. 203-218
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Tidskriftsartikel (refereegranskat)abstract
- Comparative analysis of multiple genomes in a phylogenetic framework dramatically improves the precision and sensitivity of evolutionary inference, producing more robust results than single-genome analyses can provide. The genomes of 12 Drosophila species, ten of which are presented here for the first time (sechellia, simulans, yakuba, erecta, ananassae, persimilis, willistoni, mojavensis, virilis and grimshawi), illustrate how rates and patterns of sequence divergence across taxa can illuminate evolutionary processes on a genomic scale. These genome sequences augment the formidable genetic tools that have made Drosophila melanogaster a pre-eminent model for animal genetics, and will further catalyse fundamental research on mechanisms of development, cell biology, genetics, disease, neurobiology, behaviour, physiology and evolution. Despite remarkable similarities among these Drosophila species, we identified many putatively non-neutral changes in protein-coding genes, non-coding RNA genes, and cis-regulatory regions. These may prove to underlie differences in the ecology and behaviour of these diverse species.
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| 3. |
- Tanvir, N. R., et al.
(författare)
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A γ-ray burst at a redshift of z~8.2
- 2009
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Ingår i: Nature. - 0028-0836 .- 1476-4687. ; 461, s. 1254-1257
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Tidskriftsartikel (refereegranskat)abstract
- Long-duration γ-ray bursts (GRBs) are thought to result from the explosions of certain massive stars, and some are bright enough that they should be observable out to redshifts of z>20 using current technology. Hitherto, the highest redshift measured for any object was z = 6.96, for a Lyman-α emitting galaxy. Here we report that GRB090423 lies at a redshift of z~8.2, implying that massive stars were being produced and dying as GRBs ~630Myr after the Big Bang. The burst also pinpoints the location of its host galaxy.
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| 4. |
- Kumar, B, et al.
(författare)
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Upregulated TRPC1 Channel in Vascular Injury In Vivo and Its Role in Human Neointimal Hyperplasia.
- 2006
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Ingår i: Circulation Research. - 0009-7330. ; 98:4, s. 557-563
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Tidskriftsartikel (refereegranskat)abstract
- Occlusive vascular disease is a widespread abnormality leading to lethal or debilitating outcomes such as myocardial infarction and stroke. It is part of atherosclerosis and is evoked by clinical procedures including angioplasty and grafting of saphenous vein in bypass surgery. A causative factor is the switch in smooth muscle cells to an invasive and proliferative mode, leading to neointimal hyperplasia. Here we reveal the importance to this process of TRPC1, a homolog of Drosophila transient receptor potential. Using 2 different in vivo models of vascular injury in rodents we show hyperplasic smooth muscle cells have upregulated TRPC1 associated with enhanced calcium entry and cell cycle activity. Neointimal smooth muscle cells after balloon angioplasty of pig coronary artery also express TRPC1. Furthermore, human vein samples obtained during coronary artery bypass graft surgery commonly exhibit an intimal structure containing smooth muscle cells that expressed more TRPC1 than the medial layer cells. Veins were organ cultured to allow growth of neointimal smooth muscle cells over a 2-week period. To explore the functional relevance of TRPC1, we used a specific E3-targeted antibody to TRPC1 and chemical blocker 2-aminoethoxydiphenyl borate. Both agents significantly reduced neointimal growth in human vein, as well as calcium entry and proliferation of smooth muscle cells in culture. The data suggest upregulated TRPC1 is a general feature of smooth muscle cells in occlusive vascular disease and that TRPC1 inhibitors have potential as protective agents against human vascular failure.
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| 5. |
- Chapin, III F.S., et al.
(författare)
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Resilience-based stewardship : Strategies for navigating sustainable pathways in a changing world.
- 2009
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Ingår i: Principles of ecosystem stewardship. - New York : Springer Verlag. - 9780387730332 ; , s. 319-337
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Bokkapitel (populärvet., debatt m.m.)abstract
- Accelerated global changes in climate, environment, and social–ecological systems demand a transformation in human perceptions of our place in nature and patterns of resource use. The biology and culture of Homo sapiens evolved for about 95% of our species’ history in hunting-and-gathering societies before the emergence of settled agriculture. We have lived in complex societies for about 3%, and in industrial societies using fossil fuels for about 0.1% of our history. The pace of cultural evolution, including governance arrangements and resource-use patterns, appears insufficient to adjust to the rate and magnitude of technological innovations, human population increases, and environmental impacts that have occurred. Many of these changes are accelerating, causing unsustainable exploitation of ecosystems, including many boreal and tropical forests, drylands, and marine fisheries. The net effect has been serious degradation of the planet’s life-support system on which societal development ultimately depends (see Chapters 2 and 14.
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| 6. |
- Hannikainen, D C, et al.
(författare)
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The X-ray source population of the globular cluster M15: Chandra high-resolution imaging
- 2005
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Ingår i: Monthly Notices of the Royal Astronomical Society. - : Oxford University Press (OUP). - 1365-2966 .- 0035-8711. ; 357:1, s. 325-332
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Tidskriftsartikel (refereegranskat)abstract
- The globular cluster M15 was observed on three occasions with the High Resolution Camera on- board Chandra in 2001 in order to investigate the X- ray source population in the cluster centre. After subtraction of the two bright central sources, four faint sources were identified within 50 arcsec of the core. One of these sources is probably the planetary nebula K648, making this the first positive detection of X- rays from a planetary nebula inside a globular cluster. Another two are identified with UV variables (one previously known), which we suggest are cataclysmic variables (CVs). The nature of the fourth source is more difficult to ascertain, and we discuss whether it is possibly a quiescent soft X- ray transient or also a CV.
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| 7. |
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| 8. |
- Sochalski, Julie, et al.
(författare)
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What works in chronic care management : the case of heart failure.
- 2009
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Ingår i: Health affairs (Project Hope). - : Health Affairs (Project Hope). - 1544-5208 .- 0278-2715. ; 28:1, s. 179-89
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Tidskriftsartikel (refereegranskat)abstract
- The evidence base of what works in chronic care management programs is underdeveloped. To fill the gap, we pooled and reanalyzed data from ten randomized clinical trials of heart failure care management programs to discern how program delivery methods contribute to patient outcomes. We found that patients enrolled in programs using multi-disciplinary teams and in programs using in-person communication had significantly fewer hospital readmissions and readmission days than routine care patients had. Our study offers policymakers and health plan administrators important guideposts for developing an evidence base on which to build effective policy and programmatic initiatives for chronic care management.
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