| 1. |
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| 2. |
- Charette, M. A., et al.
(författare)
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The Transpolar Drift as a Source of Riverine and Shelf-Derived Trace Elements to the Central Arctic Ocean
- 2020
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Ingår i: Journal of Geophysical Research-Oceans. - : American Geophysical Union (AGU). - 2169-9275 .- 2169-9291. ; 125:5
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Tidskriftsartikel (refereegranskat)abstract
- A major surface circulation feature of the Arctic Ocean is the Transpolar Drift (TPD), a current that transports river-influenced shelf water from the Laptev and East Siberian Seas toward the center of the basin and Fram Strait. In 2015, the international GEOTRACES program included a high-resolution pan-Arctic survey of carbon, nutrients, and a suite of trace elements and isotopes (TEIs). The cruises bisected the TPD at two locations in the central basin, which were defined by maxima in meteoric water and dissolved organic carbon concentrations that spanned 600 km horizontally and similar to 25-50 m vertically. Dissolved TEIs such as Fe, Co, Ni, Cu, Hg, Nd, and Th, which are generally particle-reactive but can be complexed by organic matter, were observed at concentrations much higher than expected for the open ocean setting. Other trace element concentrations such as Al, V, Ga, and Pb were lower than expected due to scavenging over the productive East Siberian and Laptev shelf seas. Using a combination of radionuclide tracers and ice drift modeling, the transport rate for the core of the TPD was estimated at 0.9 +/- 0.4 Sv (10(6) m(3)s(-1)). This rate was used to derive the mass flux for TEIs that were enriched in the TPD, revealing the importance of lateral transport in supplying materials beneath the ice to the central Arctic Ocean and potentially to the North Atlantic Ocean via Fram Strait. Continued intensification of the Arctic hydrologic cycle and permafrost degradation will likely lead to an increase in the flux of TEIs into the Arctic Ocean. Plain Language Summary A major feature of the Arctic Ocean circulation is the Transpolar Drift (TPD), a surface current that carries ice and continental shelf-derived materials from Siberia across the North Pole to the North Atlantic Ocean. In 2015, an international team of oceanographers conducted a survey of trace elements in the Arctic Ocean, traversing the TPD. Near the North Pole, they observed much higher concentrations of trace elements in surface waters than in regions on either side of the current. These trace elements originated from land, and their journey across the Arctic Ocean is made possible by chemical reactions with dissolved organic matter that originates mainly in Arctic rivers. This study reveals the importance of rivers and shelf processes combined with strong ocean currents in supplying trace elements to the central Arctic Ocean and onward to the Atlantic. These trace element inputs are expected to increase as a result of permafrost thawing and increased river runoff in the Arctic, which is warming at a rate much faster than anywhere else on Earth. Since many of the trace elements are essential building blocks for ocean life, these processes could lead to significant changes in the marine ecosystems and fisheries of the Arctic Ocean.
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| 3. |
- Charette, M, et al.
(författare)
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The Transpolar Drift as a Source of Riverine and Shelf‐Derived Trace Elements to the Central Arctic Ocean
- 2020
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Ingår i: Journal of Geophysical Research - Oceans. - 2169-9275 .- 2169-9291. ; 125, s. 1-34
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Tidskriftsartikel (refereegranskat)abstract
- A major surface circulation feature of the Arctic Ocean is the Transpolar Drift (TPD), a current that transports river‐influenced shelf water from the Laptev and East Siberian Seas toward the center of the basin and Fram Strait. In 2015, the international GEOTRACES program included a high‐resolution pan‐Arctic survey of carbon, nutrients, and a suite of trace elements and isotopes (TEIs). The cruises bisected the TPD at two locations in the central basin, which were defined by maxima in meteoric water and dissolved organic carbon concentrations that spanned 600 km horizontally and ~25–50 m vertically. Dissolved TEIs such as Fe, Co, Ni, Cu, Hg, Nd, and Th, which are generally particle‐reactive but can be complexed by organic matter, were observed at concentrations much higher than expected for the openocean setting. Other trace element concentrations such as Al, V, Ga, and Pb were lower than expected due to scavenging over the productive East Siberian and Laptev shelf seas. Using a combination of radionuclide tracers and ice drift modeling, the transport rate for the core of the TPD was estimated at 0.9 ± 0.4 Sv(106m3 s−1). This rate was used to derive the mass flux for TEIs that were enriched in the TPD, revealing the importance of lateral transport in supplying materials beneath the ice to the central Arctic Ocean and potentially to the North Atlantic Ocean via Fram Strait. Continued intensification of the Arctic hydrologicc ycle and permafrost degradation will likely lead to an increase in the flux of TEIs into the Arctic Ocean.
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| 4. |
- Sumaila, U. Rashid, et al.
(författare)
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WTO must ban harmful fisheries subsidies
- 2021
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Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 374:6567, s. 544-544
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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| 5. |
- Ashley, S. F., et al.
(författare)
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Intrinsic state lifetimes in Pd-103 and Cd-106,Cd-107
- 2007
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Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 76:6, s. 064302-
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Tidskriftsartikel (refereegranskat)abstract
- The mean-lifetimes, tau, of various medium-spin excited states in Pd-103 and Cd-106,Cd-107 have been deduced using the Recoil Distance Doppler Shift technique and the Differential Decay Curve Method. In Cd-106, the mean-lifetimes of the I-pi=12(+) state at E-x=5418 keV and the I-pi=11(-) state at E-x=4324 keV have been deduced as 11.4(17)ps and 8.2(7)ps, respectively. The associated beta(2) deformation within the axially-symmetric deformed rotor model for these states are 0.14(1) and 0.14(1), respectively. The beta(2) deformation of 0.14(1) for the I-pi=12(+) state in Cd-106 compares with a predicted beta(2) value from total Routhian surface (TRS) calculations of 0.17. In addition, the mean-lifetimes of the yrast I-pi = 15(-)/2 states in Pd-103 (at E-x=1262 keV) and Cd-107 (at E-x=1360 keV) have been deduced to be 31.2(44)ps and 31.4(17)ps, respectively, corresponding to beta(2) values of 0.16(1) and 0.12(1) assuming axial symmetry. Agreement with TRS calculations are good for Pd-103 but deviate for that predicted for Cd-107.
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| 6. |
- Senage, T., et al.
(författare)
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The role of antibody responses against glycans in bioprosthetic heart valve calcification and deterioration
- 2022
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Ingår i: Nature Medicine. - : Springer Science and Business Media LLC. - 1078-8956 .- 1546-170X. ; 28, s. 283-294
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Tidskriftsartikel (refereegranskat)abstract
- Bioprosthetic heart valves (BHVs) are commonly used to replace severely diseased heart valves but their susceptibility to structural valve degeneration (SVD) limits their use in young patients. We hypothesized that antibodies against immunogenic glycans present on BHVs, particularly antibodies against the xenoantigens galactose-alpha 1,3-galactose (alpha Gal) and N-glycolylneuraminic acid (Neu5Gc), could mediate their deterioration through calcification. We established a large longitudinal prospective international cohort of patients (n = 1668, 34 +/- 43 months of follow-up (0.1-182); 4,998 blood samples) to investigate the hemodynamics and immune responses associated with BHVs up to 15 years after aortic valve replacement. Early signs of SVD appeared in <5% of BHV recipients within 2 years. The levels of both anti-alpha Gal and anti-Neu5Gc IgGs significantly increased one month after BHV implantation. The levels of these IgGs declined thereafter but anti-alpha Gal IgG levels declined significantly faster in control patients compared to BHV recipients. Neu5Gc, anti-Neu5Gc IgG and complement deposition were found in calcified BHVs at much higher levels than in calcified native aortic valves. Moreover, in mice, anti-Neu5Gc antibodies were unable to promote calcium deposition on subcutaneously implanted BHV tissue engineered to lack alpha Gal and Neu5Gc antigens. These results indicate that BHVs manufactured using donor tissues deficient in alpha Gal and Neu5Gc could be less prone to immune-mediated deterioration and have improved durability. In a large cohort of patients who underwent aortic valve replacement, antibody responses to glycans present in bioprosthetic heart valves, notably galactose-alpha 1,3-galactose and N-glycolylneuraminic acid, were implicated in valve calcification and deterioration.
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| 7. |
- Andgren, Karin, et al.
(författare)
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Recoil distance method lifetime measurements in Cd-107 and Pd-101.
- 2006
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Ingår i: Frontiers in Nuclear Structure Astrophysics, and Reactions: FINUSTAR. - MELVILLE, NY : AMER INST PHYSICS. - 0735403236 ; , s. 391-393
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Konferensbidrag (refereegranskat)abstract
- Preliminary lifetime values have been measured for a number of near-yrast states in the odd-A transitional nuclei Cd-107 and Pd-103. The reaction used to populate the nuclei of interest was Mo-98(C-12, 3nx alpha)Cd-107, Pd-103, with the beam delivered by the tandem accelerator of the Wright Nuclear Structure Laboratory at an incident beam energy of 60 MeV. Our experiment was aimed at the investigation of collective excitations built on the unnatural parity, v h(11/2) orbital, specifically by measuring the B(E2) values of decays from the excited levels built on this intrinsic structure, using the Doppler Recoil Distance Method. We report lifetimes and associated transition probabilities for decays from the 15/2(-) and the 19/2(-) states in Cd-107 and the first measurement of the 15/2- state in Pd-103. These results suggest that neither a simple rotational or vibrational interpretation is sufficient to explain the observed structures.
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| 8. |
- Ashley, S. F., et al.
(författare)
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Lifetime determination of excited states in Cd-106
- 2007
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Ingår i: Acta Physica Polonica B. - 0587-4254 .- 1509-5770. ; 38:4, s. 1385-1388
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Tidskriftsartikel (refereegranskat)abstract
- Two separate experiments using the Differential Decay Curve Method have been performed to extract mean lifetimes of excited states in 106 Cd. The inedium-spin states of interest were populated by the Mo-98(C-12, 4n) Cd-106 reaction performed at the Wright Nuclear Structure Lab., Yale University. From this experiment, two isomeric state mean lifetimes have been deduced. The low-lying states were populated by the Mo-96(C-13, 3n)Cd-106 reaction performed at the Institut fur Kernphysik, Universitat zu Koln. The mean lifetime of the I-pi = 2(1)(+) state was deduced, tentatively, as 16.4(9) ps. This value differs from the previously accepted literature value from Coulomb excitation of 10.43(9) ps.
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| 9. |
- Grodner, E., et al.
(författare)
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Hindered Gamow-Teller Decay to the Odd-Odd N=Z 62Ga: Absence of Proton-Neutron T=0 Condensate in A=62
- 2014
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Ingår i: Physical Review Letters. - 1079-7114. ; 113:9
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Tidskriftsartikel (refereegranskat)abstract
- Search for a new kind of superfluidity built on collective proton-neutron pairs with aligned spin is performed studying the Gamow-Teller decay of the T=1, Jπ=0+ ground state of Ge62 into excited states of the odd-odd N=Z nucleus Ga62. The experiment is performed at GSI Helmholtzzentrum für Schwerionenforschung with the Ge62 ions selected by the fragment separator and implanted in a stack of Si-strip detectors, surrounded by the RISING Ge array. A half-life of T1/2=82.9(14) ms is measured for the Ge62 ground state. Six excited states of Ga62, populated below 2.5 MeV through Gamow-Teller transitions, are identified. Individual Gamow-Teller transition strengths agree well with theoretical predictions of the interacting shell model and the quasiparticle random phase approximation. The absence of any sizable low-lying Gamow-Teller strength in the reported beta-decay experiment supports the hypothesis of a negligible role of coherent T=0 proton-neutron correlations in Ga62.
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| 10. |
- Abbott, Benjamin W., et al.
(författare)
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Biomass offsets little or none of permafrost carbon release from soils, streams, and wildfire : an expert assessment
- 2016
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Ingår i: Environmental Research Letters. - : IOP Publishing. - 1748-9326. ; 11:3
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Tidskriftsartikel (refereegranskat)abstract
- As the permafrost region warms, its large organic carbon pool will be increasingly vulnerable to decomposition, combustion, and hydrologic export. Models predict that some portion of this release will be offset by increased production of Arctic and boreal biomass; however, the lack of robust estimates of net carbon balance increases the risk of further overshooting international emissions targets. Precise empirical or model-based assessments of the critical factors driving carbon balance are unlikely in the near future, so to address this gap, we present estimates from 98 permafrost-region experts of the response of biomass, wildfire, and hydrologic carbon flux to climate change. Results suggest that contrary to model projections, total permafrost-region biomass could decrease due to water stress and disturbance, factors that are not adequately incorporated in current models. Assessments indicate that end-of-the-century organic carbon release from Arctic rivers and collapsing coastlines could increase by 75% while carbon loss via burning could increase four-fold. Experts identified water balance, shifts in vegetation community, and permafrost degradation as the key sources of uncertainty in predicting future system response. In combination with previous findings, results suggest the permafrost region will become a carbon source to the atmosphere by 2100 regardless of warming scenario but that 65%-85% of permafrost carbon release can still be avoided if human emissions are actively reduced.
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| 11. |
- Bribiesca-Contreras, G., et al.
(författare)
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Benthic megafauna of the western Clarion-Clipperton Zone, Pacific Ocean
- 2022
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Ingår i: Zookeys. - : Pensoft Publishers. - 1313-2989 .- 1313-2970. ; :1113, s. 1-110
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Tidskriftsartikel (refereegranskat)abstract
- There is a growing interest in the exploitation of deep-sea mineral deposits, particularly on the abyssal seafloor of the central Pacific Clarion-Clipperton Zone (CCZ), which is rich in polymetallic nodules. In order to effectively manage potential exploitation activities, a thorough understanding of the biodiversity, community structure, species ranges, connectivity, and ecosystem functions across a range of scales is needed. The benthic megafauna plays an important role in the functioning of deep-sea ecosystems and represents an important component of the biodiversity. While megafaunal surveys using video and still images have provided insight into CCZ biodiversity, the collection of faunal samples is needed to confirm are very rarely carried out. Using a Remotely Operated Vehicle, 55 specimens of benthic megafauna were-collected from seamounts and abyssal plains in three Areas of Particular Environmental Interest (APEI 1, APEI 4, and APEI 7) at 3100-5100 m depth in the western CCZ. Using both morphological and molecular evidence, 48 different morphotypes belonging to five phyla were found, only nine referrable to known species, and 39 species potentially new to science. This work highlights the need for detailed taxonomic studies incorporating genetic data, not only within the CCZ, but in other bathyal, abyssal, and hadal regions, as representative genetic reference libraries that could facilitate the generation of species inventories.
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| 12. |
- Glover, AG, et al.
(författare)
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The London Workshop on the Biogeography and Connectivity of the Clarion-Clipperton Zone
- 2016
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Ingår i: Research Ideas and Outcomes. - : Pensoft Publishers. - 2367-7163. ; 2
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Background Recent years have seen a rapid increase in survey and sampling expeditions to the Clarion-Clipperton Zone (CCZ) abyssal plain, a vast area of the central Pacific that is currently being actively explored for deep-sea minerals (ISA, 2016). Critical to the development of evidence-based environmental policy in the CCZ are data on the biogeography and connectivity of species at a CCZ-regional level. New information The London Workshop on the Biogeography and Connectivity of the CCZ was convened to support the integration and synthesis of data from European Union (EU) CCZ projects, supported by the EU Managing Impacts of Deep-Sea Resource Exploitation (MIDAS) and EU Joint Programming Initiative Healthy and Productive Seas and Oceans (JPI Oceans) projects. The London Workshop had three clear goals: (1) To explore, review and synthesise the latest molecular biogeography and connectivity data from across recent CCZ cruises from both contractor and academia-funded projects; (2) To develop complementary and collaborative institutional and program-based academic publication plans to avoid duplication of effort and ensure maximum collaborative impact; (3) To plan a joint synthetic data publication highlighting key results from a range of planned molecular biogeography/connectivity publications. 32 participants attended the workshop at the Natural History Museum in London from 10-12 May 2016. Presentations and discussions are summarised in this report covering (1) overviews of current CCZ environmental projects, (2) policy and industry perspectives, (3) synthesis of DNA taxonomy and biogeography studies, (4) summaries of the latest population genetic studies, (5) summaries of the latest broader morphological context, (6) an overview of publication and proposal plans to maximise collaborative opportunities and finally a series of workshop recommendations.
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| 13. |
- Jones, Daniel O.B., et al.
(författare)
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Environment, ecology, and potential effectiveness of an area protected from deep-sea mining (Clarion Clipperton Zone, abyssal Pacific)
- 2021
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Ingår i: Progress in Oceanography. - : Elsevier BV. - 0079-6611. ; 197:September-October 2021
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Tidskriftsartikel (refereegranskat)abstract
- To protect the range of habitats, species, and ecosystem functions in the Clarion Clipperton Zone (CCZ), a region of interest for deep-sea polymetallic nodule mining in the Pacific, nine Areas of Particular Environmental Interest (APEIs) have been designated by the International Seabed Authority (ISA). The APEIs are remote, rarely visited and poorly understood. Here we present and synthesise all available observations made at APEI-6, the most north eastern APEI in the network, and assess its representativity of mining contract areas in the eastern CCZ. The two studied regions of APEI-6 have a variable morphology, typical of the CCZ, with hills, plains and occasional seamounts. The seafloor is predominantly covered by fine-grained sediments, and includes small but abundant polymetallic nodules, as well as exposed bedrock. The oceanographic parameters investigated appear broadly similar across the region although some differences in deep-water mass separation were evident between APEI-6 and some contract areas. Sediment biogeochemistry is broadly similar across the area in the parameters investigated, except for oxygen penetration depth, which reached >2 m at the study sites within APEI-6, deeper than that found at UK1 and GSR contract areas. The ecology of study sites in APEI-6 differs from that reported from UK1 and TOML-D contract areas, with differences in community composition of microbes, macrofauna, xenophyophores and metazoan megafauna. Some species were shared between areas although connectivity appears limited. We show that, from the available information, APEI-6 is partially representative of the exploration areas to the south yet is distinctly different in several key characteristics. As a result, additional APEIs may be warranted and caution may need to be taken in relying on the APEI network alone for conservation, with other management activities required to help mitigate the impacts of mining in the CCZ.
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| 14. |
- Molina, F., et al.
(författare)
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Tz=-1 → 0 β-Decays of 54Ni, 50Fe, 46Cr, and 42Ti and Comparison With Mirror (3He,t) Measurements
- 2015
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Ingår i: Physical Review C (Nuclear Physics). - 0556-2813. ; 91:1
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Tidskriftsartikel (refereegranskat)abstract
- We have studied the β decay of the Tz=−1, f7/2 shell nuclei Ni54, Fe50, Cr46, and Ti42 produced in fragmentation reactions. The proton separation energies in the daughter Tz=0 nuclei are relatively large (≈4–5 MeV) so studies of the γ rays are essential. The experiments were performed at GSI as part of the Stopped-beam campaign with the RISING setup consisting of 15 Euroball Cluster Ge detectors. From the newly obtained high precision β-decay half-lives, excitation energies, and β branching ratios, we were able to extract Fermi and Gamow-Teller transition strengths in these β decays. With these improved results it was possible to compare in detail the Gamow-Teller (GT) transition strengths observed in beta decay including a sensitivity limit with the strengths of the Tz=+1 to Tz=0 transitions derived from high resolution (3He,t) reactions on the mirror target nuclei at RCNP, Osaka. The accumulated B(GT) strength obtained from both experiments looks very similar although the charge exchange reaction provides information on a broader energy range. Using the “merged analysis” one can obtain a full picture of the B(GT) over the full Qβ range. Looking at the individual transitions some differences are observed, especially for the weak transitions. Their possible origins are discussed.
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| 15. |
- Amon, B., et al.
(författare)
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From first-order logic to automated word generation for Lyee
- 2003
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Ingår i: Knowledge-Based Systems. - : Elsevier BV. - 0950-7051 .- 1872-7409. ; 16:07-8, s. 413-429
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Tidskriftsartikel (refereegranskat)abstract
- A conceptual schema can be viewed as a language to describe the phenomena in a system to be modelled, i.e. a set of derivation rules and integrity constraints as well as a set of event-rules describing the behaviour of an object system. In this paper, we investigate the relationship between the Lyee software requirements concepts with various constructs in conceptual modelling. Within our work we choose the Unified Modelling Language (UML) as a modelling notation for explaining conceptual models. The result obtained models a fully expressive set of UML and First Order Logic constructs mapped into Lyee concepts.
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| 16. |
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| 17. |
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| 18. |
- Debevec, T, et al.
(författare)
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Normoxic and hypoxic performance following four weeks of normobaric hypoxic training
- 2010
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Ingår i: Aviation, Space and Environmental Medicine. - : Aerospace Medical Association. - 0095-6562 .- 1943-4448. ; 81:4, s. 387-393
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Tidskriftsartikel (refereegranskat)abstract
- INTRODUCTION:Although training in hypoxia has been suggested to improve sea level and altitude performance, most studies have only evaluated its effect on maximal aerobic capacity in either normoxia or hypoxia. The present study evaluated the effect of a live low-train high training regimen on both normoxic and hypoxic endurance performance and aerobic capacity.METHODS:There were 18 male subjects who performed 20 training sessions in either a normoxic (F(IO2) = 0.21) or hypoxic (F(IO2) = 0.12) environment. Both the Control (N = 9) and Hypoxic (N = 9) group subjects trained at an intensity that maintained their heart rate at a level corresponding to that elicited at 50% of peak power output attained in normoxia or hypoxia, respectively. Before, during, upon completion, and 10 d after the protocol, subjects' aerobic capacity (VO2 peak) and endurance performance (80% of VO2 peak) were determined under normoxic and hypoxic conditions.RESULTS:Mean +/- SD normoxic VO2 peak increased significantly only in the Control group from 45.7 +/- 6.1 to 53.9 +/- 3.9 (ml x kg(-1) x min(-1)), whereas hypoxic VO2 peak did not improve in either group. The Control group exhibited significant improvements in normoxic, but not hypoxic peak power output (PPO) and time to exhaustion, whereas the Hypoxic group only exhibited improvements in normoxic time to exhaustion. During each testing period, we also assessed pulmonary function, selected hematological variables, and anthropometry. There were no significant changes in these variables in either group after the training protocol.CONCLUSION:The hypoxic training regimen used in the present study had no significant effect on altitude and sea level performance.
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| 19. |
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| 20. |
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| 21. |
- Glover, Adrian G, et al.
(författare)
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Abyssal fauna of the UK-1 polymetallic nodule exploration claim, Clarion-Clipperton Zone, central Pacific Ocean: Echinodermata.
- 2016
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Ingår i: Biodiversity data journal. - 1314-2828. ; 4
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Tidskriftsartikel (refereegranskat)abstract
- We present data from a DNA taxonomy register of the abyssal benthic Echinodermata collected as part of the Abyssal Baseline (ABYSSLINE) environmental survey cruise 'AB01' to the UK Seabed Resources Ltd (UKSRL) polymetallic-nodule exploration claim 'UK-1' in the eastern Clarion-Clipperton Zone (CCZ), central Pacific Ocean abyssal plain. Morphological and genetic data are presented for 17 species (4 Asteroidea, 4 Crinoidea, 2 Holothuroidea and 7 Ophiuroidea) identified by a combination of morphological and genetic data. No taxa matched previously published genetic sequences, but 8 taxa could be assigned to previously-described species based on morphology, although here we have used a precautionary approach in taxon assignments to avoid over-estimating species ranges. The Clarion-Clipperton Zone is a region undergoing intense exploration for potential deep-sea mineral extraction. We present these data to facilitate future taxonomic and environmental impact study by making both data and voucher materials available through curated and accessible biological collections.
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| 22. |
- Jendzurski, John R., et al.
(författare)
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Image quality testing : Selection of images for assessing test subject input
- 2014
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Ingår i: International Journal on Smart Sensing and Intelligent Systems. - 1178-5608. ; 7:5, s. 110-113
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Tidskriftsartikel (refereegranskat)abstract
- Determining image quality is dependent to some degree on human interpretation. Although entirely subjective methods of evaluating image quality may be adequate for consumer applications, they are not acceptable for security and safety applications where operator interpretation may lead to missing a threat or finding threats where they do not exist. Therefore, methods must be developed to ensure that the imagery used in security and safety applications are of sufficient quality to allow the operator to perform his job accurately and efficiently. NIST has developed a method to quantify the capability of imagers to provide images of sufficient quality to allow humans to perform specific perception-based tasks. A one-time humanperception based step is required that results in perception coefficients that are combined with lab-measured objective image quality indicators (IQIs) to calculate image quality. This work uses a d′ evaluation method to examine the performance of test subjects in the human-perception based step, which was identification of a fire hazard in a set of grey-scale infrared images.
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| 23. |
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| 24. |
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| 25. |
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| 26. |
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| 27. |
- Mekjavic, I.B., et al.
(författare)
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Evaluation of hypoxic training protocols
- 2009
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Ingår i: Aviation, Space and Environmental Medicine. - 0095-6562 .- 1943-4448. ; 80:3, s. 289-289
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Tidskriftsartikel (refereegranskat)abstract
- Acute exposure to high altitude impairs performance, both aerobic and psychomotor. Consequently preparation of personnel to be deployed to high attitude regions should incorporate a programme of altitude acclimatisation. The aim of the present study was to evaluate the effect of several training programmes on sea level and altitude performance: Live low-Train High (LL-TH), Intermittent Hypoxic Training (IHT), Respiratory Muscle Training (RMT), and Sleep High-Train Low (SH-TL).
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| 28. |
- Menger, MD, et al.
(författare)
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Experimental models to study microcirculatory dysfunction in muscle ischemia-reperfusion and osteomyocutaneous flap transfer
- 2003
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Ingår i: Langenbeck's Archives of Surgery. - : Springer Science and Business Media LLC. - 1435-2451 .- 1435-2443. ; 388:5, s. 281-290
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Tidskriftsartikel (refereegranskat)abstract
- Background. During the past decade, experimental studies have provided convincing evidence that microcirculatory dysfunction plays a pivotal role in the manifestation of tissue injury in ischemia-reperfusion and osteomyocutaneous flap transfer. The study of the mechanisms of injury, however, requires sophisticated experimental in vivo models. With the use of microsurgical techniques, osteomyocutaneous flap transfer can successfully be performed in rat hind limbs, allowing in vivo fluorescent microscopic analysis of post-ischemic microcirculatory dysfunction in all tissues involved, including periosteum, striated muscle, subcutis and skin. The drawback of this "acute" model is that the period of analysis is restricted to a few hours only. Method. To overcome this limitation, the "chronic" dorsal skinfold chamber preparation, containing striated muscle and subcutis, can be used. This model allows one to study microcirculatory dysfunction after both tourniquet-induced and pressure-induced ischemia-reperfusion-induced tissue injury over a period of up to 3 weeks. Results. With the use of these models, recent investigations have demonstrated that ischemia-reperfusion and osteomyocutaneous flap transfer are associated with capillary perfusion failure (no-reflow), mediated by intravascular hemoconcentration, endothelial swelling and endothelin (ET)-1-mediated microvascular constriction. In addition, post-ischemic reperfusion provokes an inflammatory response (reflow paradox) in post-capillary venules, which is characterized by beta(2)-integrin-mediated and intercellular adhesion molecule (ICAM)-1-mediated leukocyte adhesion and vascular hyperpermeability, which results in interstitial edema formation. Treatment studies have produced evidence that isovolemic hemodilution and heat shock protein induction are successful in ameliorating capillary no-reflow, while blockade of adhesion molecules, inactivation of oxygen radicals and, also, induction of heat shock proteins, are capable of reducing the post-ischemic inflammatory response. Conclusion. These experimental results not only demonstrate the importance of the use of advanced in vivo methods to delineate pathophysiological mechanisms in complex disease models, but may also provide a basis for potential prospective randomized trials to test the benefit for the patient in the daily clinical routine.
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| 29. |
- Simon-Lledó, Erik, et al.
(författare)
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Carbonate compensation depth drives abyssal biogeography in the northeast Pacific.
- 2023
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Ingår i: Nature ecology & evolution. - 2397-334X. ; 7, s. 1388-97
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Tidskriftsartikel (refereegranskat)abstract
- Abyssal seafloor communities cover more than 60% of Earth's surface. Despite their great size, abyssal plains extend across modest environmental gradients compared to other marine ecosystems. However, little is known about the patterns and processes regulating biodiversity or potentially delimiting biogeographical boundaries at regional scales in the abyss. Improved macroecological understanding of remote abyssal environments is urgent as threats of widespread anthropogenic disturbance grow in the deep ocean. Here, we use a new, basin-scale dataset to show the existence of clear regional zonation in abyssal communities across the 5,000km span of the Clarion-Clipperton Zone (northeast Pacific), an area targeted for deep-sea mining. We found two pronounced biogeographic provinces, deep and shallow-abyssal, separated by a transition zone between 4,300 and 4,800m depth. Surprisingly, species richness was maintained across this boundary by phylum-level taxonomic replacements. These regional transitions are probably related to calcium carbonate saturation boundaries as taxa dependent on calcium carbonate structures, such as shelled molluscs, appear restricted to the shallower province. Our results suggest geochemical and climatic forcing on distributions of abyssal populations over large spatial scales and provide a potential paradigm for deep-sea macroecology, opening a new basis for regional-scale biodiversity research and conservation strategies in Earth's largest biome.
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- Thomas, E. A., et al.
(författare)
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Chiridota heheva-the cosmopolitan holothurian
- 2020
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Ingår i: Marine Biodiversity. - : Springer Science and Business Media LLC. - 1867-1616 .- 1867-1624. ; 50:6
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Tidskriftsartikel (refereegranskat)abstract
- Chemosynthetic ecosystems have long been acknowledged as key areas of enrichment for deep-sea life, supporting hundreds of endemic species. Echinoderms are among the most common taxa inhabiting the periphery of chemosynthetic environments, and of these, chiridotid holothurians are often the most frequently observed. Yet, published records of chiridotids in these habitats are often noted only as supplemental information to larger ecological studies and several remain taxonomically unverified. This study therefore aimed to collate and review all known records attributed to Chiridota Eschscholtz, 1829, and to conduct the first phylogenetic analysis into the relationship of these chiridotid holothurians across global chemosynthetic habitats. We show that Chiridota heheva Pawson & Vance, 2004 is a globally widespread, cosmopolitan holothurian that occupies all three types of deep-sea chemosynthetic ecosystem-hydrothermal vents, cold seeps and organic falls-as an organic-enrichment opportunist. Furthermore, we hypothesise that C. heheva may be synonymous with another vent-endemic chiridotid, Chiridota hydrothermica Smirnov et al., 2000, owing to the strong morphological, ecological and biogeographical parallels between the two species, and predict that any chiridotid holothurians subsequently discovered at global reducing environments will belong to this novel species complex. This study highlights the importance of understudied, peripheral taxa, such as holothurians, to provide insights to biogeography, connectivity and speciation at insular deep-sea habitats.
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