| 1. |
- Abazov, V. M., et al.
(författare)
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The upgraded DO detector
- 2006
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Ingår i: Nuclear Instruments and Methods in Physics Research Section A. - : Elsevier BV. - 0168-9002 .- 1872-9576. ; 565:2, s. 463-537
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Tidskriftsartikel (refereegranskat)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. |
- Regan, P H, et al.
(författare)
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Vibrational and rotational sequences in Mo-101 and Ru-103,Ru-4 studied via multinucleon transfer reactions
- 2005
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Ingår i: Acta Physica Polonica B. - 0587-4254 .- 1509-5770. ; 36:4, s. 1313-1322
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Tidskriftsartikel (refereegranskat)abstract
- The near-yrast states of Mo-101(42)59 and Ru-103,4(44)59,60 have been studied following their population via heavy-ion multinucleon transfer reactions between a Xe-136 beam and a thin, self-supporting Mo-100 target. The ground state sequence in Ru-104 can be understood as demonstrating a simple evolution from a quasi-vibrational structure at lower spins to statically deformed, quasi-rotational excitation involving the population of a pair of low-Omega h(11/2) neutron orbitals. The effect of the decoupled h(11/2) orbital on this vibration-to-rotational evolution is demonstrated by an extension of the "E-GOS" prescription to include odd-A nuclei. The experimental results are also compared with self-consistent Total Routhian Surface calculations which also highlight the polarising role of the highly aligned neutron h(11/2) orbital in these nuclei.
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| 3. |
- Bentley, M. A., et al.
(författare)
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Isospin symmetry of odd-odd mirror nuclei: Identification of excited states in N=Z-2 Mn-48
- 2006
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Ingår i: Physical Review Letters. - 1079-7114. ; 97:13: 132501
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Tidskriftsartikel (refereegranskat)abstract
- Excited states have been observed in the N=Z-2 odd-odd nucleus Mn-48 for the first time. Through comparison with the structure of V-48, a first high-spin study of an odd-odd mirror pair has been achieved. Differences between the T=1 analogue states in this pair have been interpreted in terms of Coulomb effects, with the aid of shell-model calculations in the full pf valence space. Unlike other mirror pairs, the energy differences have been interpreted almost entirely as due to a monopole effect associated with smooth changes in radius (or deformation) as a function of angular momentum. In addition, the large energy shift between analogue negative-parity states is interpreted in terms of the electromagnetic spin-orbit interaction in nuclei.
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| 4. |
- Kröll, T., et al.
(författare)
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Transfer Reactions on Neutron-rich Nuclei at REX-ISOLDE
- 2009
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Ingår i: AIP Conference Proceedings. - 1551-7616 .- 0094-243X. ; 1165, s. 363-368 461
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Konferensbidrag (refereegranskat)abstract
- We report on one- and two-neutron transfer reactions to study the single-particle properties of nuclei at the border of the "island of inversion". The (d,p)- and (t,p)-reactions in inverse kinematics on the neutron-rich isotope Mg-30, delivered as radioactive beam by the REX-ISOLDE facility, have been investigated. The outgoing protons have been detected and identified by a newly built array of Si detectors. The gamma-decay of excited states has been detected in coincidence by the MINIBALL array. First results for Mg-31 and from the search for the second, spherical, 0(+) state in Mg-32 are presented.
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| 5. |
- Limpens, J., et al.
(författare)
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Peatlands and the carbon cycle : from local processes to global implications – a synthesis
- 2008
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Ingår i: Biogeosciences. - : Copernicus GmbH. - 1726-4170 .- 1726-4189. ; 5:5, s. 1475-1491
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Forskningsöversikt (refereegranskat)abstract
- Peatlands cover only 3% of the Earth's land surface but boreal and subarctic peatlands store about 15-30% of the world's soil carbon ( C) as peat. Despite their potential for large positive feedbacks to the climate system through sequestration and emission of greenhouse gases, peatlands are not explicitly included in global climate models and therefore in predictions of future climate change. In April 2007 a symposium was held in Wageningen, the Netherlands, to advance our understanding of peatland C cycling. This paper synthesizes the main findings of the symposium, focusing on (i) small-scale processes, (ii) C fluxes at the landscape scale, and (iii) peatlands in the context of climate change. The main drivers controlling most are related to some aspects of hydrology. Despite high spatial and annual variability in Net Ecosystem Exchange ( NEE), the differences in cumulative annual NEE are more a function of broad scale geographic location and physical setting than internal factors, suggesting the existence of strong feedbacks. In contrast, trace gas emissions seem mainly controlled by local factors. Key uncertainties remain concerning the existence of perturbation thresholds, the relative strengths of the CO2 and CH4 feedback, the links among peatland surface climate, hydrology, ecosystem structure and function, and trace gas biogeochemistry as well as the similarity of process rates across peatland types and climatic zones. Progress on these research areas can only be realized by stronger co-operation between disciplines that address different spatial and temporal scales.
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| 6. |
- Smith, J. F., et al.
(författare)
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Excited states and signature inversion in Cs-116
- 2006
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 74:3, s. 034310-
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Tidskriftsartikel (refereegranskat)abstract
- Excited states have been observed for the first time in the very neutron-deficient, odd-odd nucleus, Cs-116(55)61. The assignment to Cs-116 has been made by the detection of gamma rays in coincidence with evaporated charged particles and with evaporation residues. The observed states form a rotational band which has been assigned to the nu(h(11/2)) circle times pi(h(11/2)) configuration. Tentative spin assignments have been made on the basis of systematic comparisons with neighboring cesium isotopes. A low-spin signature inversion is observed in the band at a rotational frequency of about 0.23 MeV/h. The observed signature inversions in the odd-odd Cs116-126 isotopes have been compared with the results of extended total Routhian surface calculations, in which signature inversion arises as a consequence of quadrupole-pairing correlations and triaxial deformation. As previously shown for some of the odd-odd A similar or equal to 120 isotopes, the calculations reproduce the signature inversions reasonably well.
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| 7. |
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| 8. |
- Guilford, Tim, et al.
(författare)
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GPS tracking of the foraging movements of Manx Shearwaters Puffinus puffinus breeding on Skomer Island, Wales
- 2008
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Ingår i: Ibis. - 1474-919X. ; 150, s. 462-473
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Tidskriftsartikel (refereegranskat)abstract
- We report the first successful use of miniature Global Positioning System loggers to track the ocean-going behaviour of a c. 400g seabird, the Manx Shearwater Puffinus puffinus. During three field seasons, breeding birds were tracked during the incubation and chick rearing periods on their foraging excursions from the large colony on Skomer Island, Pembrokeshire, UK. Foraging effort was concentrated in the Irish Sea. Likely foraging areas were identified to the north off the Mull of Galloway (some 330km from Skomer), in Dundalk Bay, Cardigan Bay, and more diffusely to the west of the colony both locally and off southern Ireland. No foraging excursions were recorded significantly to the south of the colony, conflicting with the conclusions of earlier studies based on ringing recoveries and off-shore observations. We discuss several explanations including the hypothesis that foraging may have shifted substantially northwards in recent decades (although the possibility that breeding birds forage further south in the very early part of the season remains open). We found no obvious relationship between birds’ positions and water depth, although night-time observations were more likely to be in shallower water than day-time observations. We also found that despite the fact that shearwaters can be observed rafting off-shore from their colonies in the hours prior to making landfall at night, breeding birds are usually located much further from the colony in the last eight hours before arrival, a finding that has significance for the likely effectiveness of marine protection areas if they are only local to the colony. Short sequences of precise second-by-second fixes gathered every two hours enabled us to measure movement speed and direction. Movement speeds were bimodal, corresponding to sitting on the water and flying, with flight behaviour separable into erratic (perhaps indicative of searching for food) and directional (perhaps indicative of travelling). Movement behaviour had a diurnal pattern, with flight predominating in the morning and evening, with more sitting at night and around midday. We also provide a first direct measurement of mean flight speed during directional flight (approximately 40 kmh-1), slower than a shearwater’s predicted Vmr (maximum range velocity) and suggesting that birds are exploiting wave or dynamic soaring during long-distance travel.
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| 9. |
- Lundberg, Jon O., et al.
(författare)
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Nitrate and nitrite in biology, nutrition and therapeutics
- 2009
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Ingår i: Nature Chemical Biology. - : Springer Science and Business Media LLC. - 1552-4450 .- 1552-4469. ; 5:12, s. 865-869
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Tidskriftsartikel (refereegranskat)abstract
- Inorganic nitrate and nitrite from endogenous or dietary sources are metabolized in vivo to nitric oxide (NO) and other bioactive nitrogen oxides. The nitrate-nitrite-NO pathway is emerging as an important mediator of blood flow regulation, cell signaling, energetics and tissue responses to hypoxia. The latest advances in our understanding of the biochemistry, physiology and therapeutics of nitrate, nitrite and NO were discussed during a recent 2-day meeting at the Nobel Forum, Karolinska Institutet in Stockholm.
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| 10. |
- Valiente-Dobon, JJ, et al.
(författare)
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Evidence for nontermination of rotational bands in Kr-74
- 2005
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Ingår i: Physical Review Letters. - 1079-7114. ; 95:23
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Tidskriftsartikel (refereegranskat)abstract
- Three rotational bands in Kr-74 were studied up to (in one case one transition short of) the maximum spin I-max of their respective single-particle configurations. Their lifetimes have been determined using the Doppler-shift attenuation method. The deduced transition quadrupole moments reveal a modest decrease, but far from a complete loss of collectivity at the maximum spin I-max. This feature, together with the results of mean field calculations, indicates that the observed bands do not terminate at I=I-max.
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