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Sökning: WFRF:(Wilkin C)

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1.
  • 2021
  • swepub:Mat__t
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2.
  • Kanai, M, et al. (författare)
  • 2023
  • swepub:Mat__t
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3.
  • Niemi, MEK, et al. (författare)
  • 2021
  • swepub:Mat__t
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4.
  • Glasbey, JC, et al. (författare)
  • 2021
  • swepub:Mat__t
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5.
  • Tabiri, S, et al. (författare)
  • 2021
  • swepub:Mat__t
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6.
  • Bravo, L, et al. (författare)
  • 2021
  • swepub:Mat__t
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7.
  • 2021
  • swepub:Mat__t
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9.
  • Khatri, C, et al. (författare)
  • Outcomes after perioperative SARS-CoV-2 infection in patients with proximal femoral fractures: an international cohort study
  • 2021
  • Ingår i: BMJ open. - : BMJ. - 2044-6055. ; 11:11, s. e050830-
  • Tidskriftsartikel (refereegranskat)abstract
    • Studies have demonstrated high rates of mortality in people with proximal femoral fracture and SARS-CoV-2, but there is limited published data on the factors that influence mortality for clinicians to make informed treatment decisions. This study aims to report the 30-day mortality associated with perioperative infection of patients undergoing surgery for proximal femoral fractures and to examine the factors that influence mortality in a multivariate analysis.SettingProspective, international, multicentre, observational cohort study.ParticipantsPatients undergoing any operation for a proximal femoral fracture from 1 February to 30 April 2020 and with perioperative SARS-CoV-2 infection (either 7 days prior or 30-day postoperative).Primary outcome30-day mortality. Multivariate modelling was performed to identify factors associated with 30-day mortality.ResultsThis study reports included 1063 patients from 174 hospitals in 19 countries. Overall 30-day mortality was 29.4% (313/1063). In an adjusted model, 30-day mortality was associated with male gender (OR 2.29, 95% CI 1.68 to 3.13, p<0.001), age >80 years (OR 1.60, 95% CI 1.1 to 2.31, p=0.013), preoperative diagnosis of dementia (OR 1.57, 95% CI 1.15 to 2.16, p=0.005), kidney disease (OR 1.73, 95% CI 1.18 to 2.55, p=0.005) and congestive heart failure (OR 1.62, 95% CI 1.06 to 2.48, p=0.025). Mortality at 30 days was lower in patients with a preoperative diagnosis of SARS-CoV-2 (OR 0.6, 95% CI 0.6 (0.42 to 0.85), p=0.004). There was no difference in mortality in patients with an increase to delay in surgery (p=0.220) or type of anaesthetic given (p=0.787).ConclusionsPatients undergoing surgery for a proximal femoral fracture with a perioperative infection of SARS-CoV-2 have a high rate of mortality. This study would support the need for providing these patients with individualised medical and anaesthetic care, including medical optimisation before theatre. Careful preoperative counselling is needed for those with a proximal femoral fracture and SARS-CoV-2, especially those in the highest risk groups.Trial registration numberNCT04323644
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12.
  • Psaridi, A., et al. (författare)
  • Discovery of two warm mini-Neptunes with contrasting densities orbiting the young K3V star TOI-815
  • 2024
  • Ingår i: Astronomy and Astrophysics. - 0004-6361 .- 1432-0746. ; 685
  • Tidskriftsartikel (refereegranskat)abstract
    • We present the discovery and characterization of two warm mini-Neptunes transiting the K3V star TOI-815 in a K–M binary system. Analysis of its spectra and rotation period reveal the star to be young, with an age of 200+−400200 Myr. TOI-815b has a 11.2-day period and a radius of 2.94 ± 0.05 R+ with transits observed by TESS, CHEOPS, ASTEP, and LCOGT. The outer planet, TOI-815c, has a radius of 2.62 ± 0.10 R+, based on observations of three nonconsecutive transits with TESS; targeted CHEOPS photometry and radial velocity follow-up with ESPRESSO were required to confirm the 35-day period. ESPRESSO confirmed the planetary nature of both planets and measured masses of 7.6 ± 1.5 M+ (ρP = 1.64+−003331 g cm−3) and 23.5 ± 2.4 M+ (ρP = 7.2+−1110 g cm−3), respectively. Thus, the planets have very different masses, which is unusual for compact multi-planet systems. Moreover, our statistical analysis of mini-Neptunes orbiting FGK stars suggests that weakly irradiated planets tend to have higher bulk densities compared to those undergoing strong irradiation. This could be ascribed to their cooler atmospheres, which are more compressed and denser. Internal structure modeling of TOI-815b suggests it likely has a H-He atmosphere that constitutes a few percent of the total planet mass, or higher if the planet is assumed to have no water. In contrast, the measured mass and radius of TOI-815c can be explained without invoking any atmosphere, challenging planetary formation theories. Finally, we infer from our measurements that the star is viewed close to pole-on, which implies a spin-orbit misalignment at the 3σ level. This emphasizes the peculiarity of the system’s orbital architecture, and probably hints at an eventful dynamical history.
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13.
  • Ralimanana, H., et al. (författare)
  • Madagascar’s extraordinary biodiversity: Threats and opportunities
  • 2022
  • Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 378:6623
  • Forskningsöversikt (refereegranskat)abstract
    • Madagascar’s unique biota is heavily affected by human activity and is under intense threat. Here, we review the current state of knowledge on the conservation status of Madagascar’s terrestrial and freshwater biodiversity by presenting data and analyses on documented and predicted species-level conservation statuses, the most prevalent and relevant threats, ex situ collections and programs, and the coverage and comprehensiveness of protected areas. The existing terrestrial protected area network in Madagascar covers 10.4% of its land area and includes at least part of the range of the majority of described native species of vertebrates with known distributions (97.1% of freshwater fishes, amphibians, reptiles, birds, and mammals combined) and plants (67.7%). The overall figures are higher for threatened species (97.7% of threatened vertebrates and 79.6% of threatened plants occurring within at least one protected area). International Union for Conservation of Nature (IUCN) Red List assessments and Bayesian neural network analyses for plants identify overexploitation of biological resources and unsustainable agriculture as the most prominent threats to biodiversity. We highlight five opportunities for action at multiple levels to ensure that conservation and ecological restoration objectives, programs, and activities take account of complex underlying and interacting factors and produce tangible benefits for the biodiversity and people of Madagascar.
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14.
  • Eversmann, D., et al. (författare)
  • New Method for a Continuous Determination of the Spin Tune in Storage Rings and Implications for Precision Experiments
  • 2015
  • Ingår i: Physical Review Letters. - 0031-9007 .- 1079-7114. ; 115:9
  • Tidskriftsartikel (refereegranskat)abstract
    • A new method to determine the spin tune is described and tested. In an ideal planar magnetic ring, the spin tune-defined as the number of spin precessions per turn-is given by nu(s) = gamma G (gamma is the Lorentz factor, G the gyromagnetic anomaly). At 970 MeV/c, the deuteron spins coherently process at a frequency of approximate to 120 kHz in the Cooler Synchrotron COSY. The spin tune is deduced from the up-down asymmetry of deuteron-carbon scattering. In a time interval of 2.6 s, the spin tune was determined with a precision of the order 10(-8), and to 1 x 10(-10) for a continuous 100 s accelerator cycle. This renders the presented method a new precision tool for accelerator physics; controlling the spin motion of particles to high precision is mandatory, in particular, for the measurement of electric dipole moments of charged particles in a storage ring.
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15.
  • Guidoboni, G., et al. (författare)
  • How to Reach a Thousand-Second in-Plane Polarization Lifetime with 0.97-GeV/c Deuterons in a Storage Ring
  • 2016
  • Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 117:5
  • Tidskriftsartikel (refereegranskat)abstract
    • We observe a deuteron beam polarization lifetime near 1000 s in the horizontal plane of a magnetic storage ring (COSY). This long spin coherence time is maintained through a combination of beam bunching, electron cooling, sextupole field corrections, and the suppression of collective effects through beam current limits. This record lifetime is required for a storage ring search for an intrinsic electric dipole moment on the deuteron at a statistical sensitivity level approaching 10(-29) e cm.
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16.
  • Keleta, S, et al. (författare)
  • Exclusive measurement of two-pion production in the dd -> He-4 pi pi reaction
  • 2009
  • Ingår i: Nuclear Physics A. - : Elsevier BV. - 0375-9474 .- 1873-1554. ; 825:1-2, s. 71-90
  • Tidskriftsartikel (refereegranskat)abstract
    • The results from the first kinematically complete measurement of the dd -> He-4 pi pi reaction are reported. The aim was to investigate a long standing puzzle regarding the origin of the peculiar pi pi-invariant mass distributions appearing in double pion production in light ion collisions, the so-called ABC effect. The measurements were performed at the incident deuteron energies of 712 MeV and 1029 MeV. with the WASA detector assembly at CELSIUS in Uppsala, Sweden. We report the observation of a characteristic enhancement at low pi pi-invariant mass at 712 MeV, the lowest energy yet. At the higher energy, in addition to confirming previous experimental observations, Our results reveal a strong angular dependence of the pions in the overall centre of mass system. The results are qualitatively reproduced by a theoretical model, according to which the ABC effect is described as resulting from a kinematical enhancement in the production of the pion pairs from two parallel and independent NN -> d pi sub-processes. (C) 2009 Elsevier B.V. All rights reserved.
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18.
  • Schonning, K., et al. (författare)
  • The pd -> He-3 eta pi(0) reaction at T-p=1450 MeV CELSIUS/WASA Collaboration
  • 2010
  • Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 685:1, s. 33-37
  • Tidskriftsartikel (refereegranskat)abstract
    • The cross section for the pd -> He-3 eta pi(0) reaction has been measured at a beam energy of 1450 MeV using the WASA detector at the CELSIUS storage ring. The He-3 was detected in coincidence with four photons from the decays of the two mesons. The data indicate that the production mechanism involves the formation of the Delta(1232) isobar. Although the beam energy does not allow the full peak of this resonance to be seen, the invariant mass distributions Of all three pairs of final particles are well reproduced by a phase space Monte Carlo simulation weighted with the p-wave factor of the square of the pi(0) momentum in the He-3 pi(0) system.
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19.
  • Schönning, Karin, et al. (författare)
  • Production of the omega meson in the pd -> He-3 omega reaction at 1450 MeV and 1360 MeV
  • 2009
  • Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 79:4, s. 044002-
  • Tidskriftsartikel (refereegranskat)abstract
    • The production of omega mesons in the pd -> He-3 omega reaction has been studied at two energies near the kinematic threshold, T-p = 1450 MeV and T-p = 1360 MeV. The differential cross section was measured as a function of the omega c.m. angle at both energies over the whole angular range. Whereas the results at 1360 MeV are consistent with isotropy, strong rises are observed near both the forward and backward directions at 1450 MeV. Calculations made using a two-step model with an intermediate pion fail to reproduce the shapes of the measured angular distributions and also underestimate the total cross sections.
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20.
  • Adlarson, Patrik, et al. (författare)
  • Total and differential cross sections of η-production in proton–deuteron fusion for excess energies between Qη = 13 MeV and Qη = 81 MeV
  • 2018
  • Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 782, s. 297-304
  • Tidskriftsartikel (refereegranskat)abstract
    • New data on both total and differential cross sections of the production of eta mesons in proton-deuteron fusion to He-3 eta in the excess energy region 13.6 MeV <= Q(eta) <= 80.9 MeV are presented. These data have been obtained with the WASA-at-COSY detector setup located at the Forschungszentrum Julich, using a proton beam at 15 different beam momenta between p(p) = 1.60 GeV/c and p(p) = 1.74 GeV/c. While significant structure of the total cross section is observed in the energy region 20 MeV less than or similar to Q(eta) less than or similar to 60 MeV, a previously reported sharp variation around Q(eta) approximate to 50 MeV cannot be confirmed. Angular distributions show the typical forward- peaking that was noted earlier. For the first time, it is possible to study the development of these angular distributions with rising excess energy over a wide interval.
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21.
  • Antonelli, Alexandre, 1978, et al. (författare)
  • Madagascar's extraordinary biodiversity : Evolution, distribution, and use
  • 2022
  • Ingår i: Science. - : American Association for the Advancement of Science (AAAS). - 0036-8075 .- 1095-9203. ; 378:6623, s. 962-
  • Tidskriftsartikel (refereegranskat)abstract
    • Madagascar's biota is hyperdiverse and includes exceptional levels of endemicity. We review the current state of knowledge on Madagascar's past and current terrestrial and freshwater biodiversity by compiling and presenting comprehensive data on species diversity, endemism, and rates of species description and human uses, in addition to presenting an updated and simplified map of vegetation types. We report a substantial increase of records and species new to science in recent years; however, the diversity and evolution of many groups remain practically unknown (e.g., fungi and most invertebrates). Digitization efforts are increasing the resolution of species richness patterns and we highlight the crucial role of field- and collections-based research for advancing biodiversity knowledge and identifying gaps in our understanding, particularly as species richness corresponds closely to collection effort. Phylogenetic diversity patterns mirror that of species richness and endemism in most of the analyzed groups. We highlight humid forests as centers of diversity and endemism because of their role as refugia and centers of recent and rapid radiations. However, the distinct endemism of other areas, such as the grassland-woodland mosaic of the Central Highlands and the spiny forest of the southwest, is also biologically important despite lower species richness. The documented uses of Malagasy biodiversity are manifold, with much potential for the uncovering of new useful traits for food, medicine, and climate mitigation. The data presented here showcase Madagascar as a unique " living laboratory" for our understanding of evolution and the complex interactions between people and nature. The gathering and analysis of biodiversity data must continue and accelerate if we are to fully understand and safeguard this unique subset of Earth's biodiversity.
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22.
  • Cowell, C., et al. (författare)
  • Uses and benefits of digital sequence information from plant genetic resources: Lessons learnt from botanical collections
  • 2022
  • Ingår i: Plants People Planet. - : Wiley. - 2572-2611. ; 4:1, s. 33-43
  • Tidskriftsartikel (refereegranskat)abstract
    • Societal Impact Statement Digitized molecular data are vital to numerous aspects of scientific research and genetic resource use. The Convention on Biological Diversity currently refers to this as "Digital Sequence Information" (DSI), a term not widely adopted by science and lacking a clear definition. There are concerns over the access to genetic resources and absence of benefit sharing by provider countries. Open access to DSI might exacerbate this, which is leading to increasing policy interventions and restricted access to genetic resources and DSI. We analyze current international debate and proposed solutions and provide case studies of DSI use producing tangible benefits for the provider countries and scientific research, demonstrating the importance of open access DSI to achieving conservation goals. Substantial advances in DNA sequencing over the last decades hold great potential to enhance food security and sustainable use of global biodiversity, benefiting the world's poorest people. Digital Sequence Information (DSI) plays a crucial role in catalyzing research applications that can contribute to international societal and biodiversity conservation targets. However, benefit sharing relating to DSI is difficult to identify and hindered by the lack of clear international governance and legislation, which in turn has led to a reluctance to make DSI publicly and freely available. Critically, no precise definition exists under the Convention on Biological Diversity (CBD), the Nagoya Protocol (NP), or the International Treaty for Plant Genetic Resources for Food and Agriculture (ITPGRFA). The key difference between DSI and biological resources, for which access and use are highly regulated under those frameworks, is that information is nonphysical. Information can be replicated and used without movement of, or access to, physical specimens. Thus, regulating the use of DSI is extremely challenging and remains controversial. Here, we review the regulation of DSI and the possible future steps by the international community, in the context of the benefit-sharing obligations of the CBD, NP, and ITPGRFA. We highlight how multilateral agreements work in practice and are a solution to this impasse. We provide case studies demonstrating how the Royal Botanic Gardens, Kew, and its collaborators address the uncertainty surrounding the use of DSI, illustrating tangible and equitable benefits that have arisen from such use. We conclude that open access to DSI is needed for scientific research and international policy.
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23.
  • Grace, O. M., et al. (författare)
  • Plant Power: Opportunities and challenges for meeting sustainable energy needs from the plant and fungal kingdoms
  • 2020
  • Ingår i: Plants People Planet. - : Wiley. - 2572-2611. ; 2:5, s. 446-462
  • Tidskriftsartikel (refereegranskat)abstract
    • Societal Impact Statement Bioenergy is a major component of the global transition to renewable energy technologies. The plant and fungal kingdoms offer great potential but remain mostly untapped. Their increased use could contribute to the renewable energy transition and addressing the United Nations Sustainable Development Goal 7 "Ensure access to affordable, reliable, sustainable and modern energy for all." Current research focuses on species cultivated at scale in temperate regions, overlooking the wealth of potential new sources of small-scale energy where they are most urgently needed. A shift towards diversified, accessible bioenergy technologies will help to mitigate and adapt to the threats of climate change, decrease energy poverty, improve human health by reducing indoor pollution, increase energy resilience of communities, and decrease greenhouse gas emissions from fossil fuels. SummaryBioenergy derived from plants and fungi is a major component of the global transition to renewable energy technologies. There is rich untapped diversity in the plant and fungal kingdoms that offers potential to contribute to the shift away from fossil fuels and to address the United Nations Sustainable Development Goal 7 (SDG7) "Ensure access to affordable, reliable, sustainable and modern energy for all." Energy poverty-the lack of access to modern energy services-is most acute in the Global South where biodiversity is greatest and least investigated. Our systematic review of the literature over the last 5 years (2015-2020) indicates that research efforts have targeted a very small number of plant species cultivated at scale, mostly in temperate regions. The wealth of potential new sources of bioenergy in biodiverse regions, where the implementation of SDG7 is most urgently needed, has been largely overlooked. We recommend next steps for bioenergy stakeholders-research, industry, and government-to seize opportunities for innovation to alleviate energy poverty while protecting biodiversity. Small-scale energy production using native plant species in bioenergy landscapes overcomes many pitfalls associated with bioenergy crop monocultures, such as biodiversity loss and conflict with food production. Targeted trait-based screening of plant species and biological screening of fungi are required to characterize the potential of this resource. The benefits of diversified, accessible bioenergy go beyond the immediate urgency of energy poverty as more diverse agricultural landscapes are more resilient, store more carbon, and could also reduce the drivers of the climate and environmental emergencies.
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24.
  • Knowles, Sarah C L, et al. (författare)
  • Molecular epidemiology of malaria prevalence and parasitaemia in a wild bird population.
  • 2011
  • Ingår i: Molecular Ecology. - 0962-1083. ; 20, s. 1062-1076
  • Tidskriftsartikel (refereegranskat)abstract
    • Avian malaria (Plasmodium spp.) and other blood parasitic infections of birds constitute increasingly popular model systems in ecological and evolutionary host-parasite studies. Field studies of these parasites commonly use two traits in hypothesis testing: infection status (or prevalence at the population level) and parasitaemia, yet the causes of variation in these traits remain poorly understood. Here, we use quantitative PCR to investigate fine-scale environmental and host predictors of malaria infection status and parasitaemia in a large 4-year data set from a well-characterized population of blue tits (Cyanistes caeruleus). We also examine the temporal dynamics of both traits within individuals. Both infection status and parasitaemia showed marked temporal and spatial variation within this population. However, spatiotemporal patterns of prevalence and parasitaemia were non-parallel, suggesting that different biological processes underpin variation in these two traits at this scale. Infection probability and parasitaemia both increased with host age, and parasitaemia was higher in individuals investing more in reproduction (those with larger clutch sizes). Several local environmental characteristics predicted parasitaemia, including food availability, altitude, and distance from the woodland edge. Although infection status and parasitaemia were somewhat repeatable within individuals, infections were clearly dynamic: patent infections frequently disappeared from the bloodstream, with up to 26% being lost between years, and parasitaemia also fluctuated within individuals across years in a pattern that mirrored annual population-level changes. Overall, these findings highlight the ecological complexity of avian malaria infections in natural populations, while providing valuable insight into the fundamental biology of this system that will increase its utility as a model host-parasite system.
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25.
  • Petrén, Henrik, et al. (författare)
  • eta-meson production in proton-proton collisions at excess energies of 40 and 72 MeV
  • 2010
  • Ingår i: Physical Review C. Nuclear Physics. - 0556-2813 .- 1089-490X. ; 82:5, s. 055206-
  • Tidskriftsartikel (refereegranskat)abstract
    • The production of eta mesons in proton-proton collisions has been studied using the WASA detector at the CELSIUS storage ring at excess energies of Q = 40 MeV and Q = 72 MeV. The eta was detected through its 2 gamma decay in a near-4 pi electromagnetic calorimeter, whereas the protons were measured by a combination of straw chambers and plastic scintillator planes in the forward hemisphere. About 6.9 x 10(4) and 9.3 x 10(4) events were found at Q = 40 MeV and Q = 72 MeV, respectively, with background contributions of less than 5%. A simple parametrization of the production cross section in terms of low partial waves was used to evaluate the acceptance corrections. Strong evidence was found for the influence of higher partial waves. The Dalitz plots show the presence of p waves in both the pp and the eta {pp} systems and the angular distributions of the eta in the center-of-mass frame suggest the influence of d-wave eta mesons.
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26.
  • Schönning, Karin, et al. (författare)
  • Polarisation of the omega meson in the pd -> He-3 omega reaction at 1360 and 1450 MeV
  • 2008
  • Ingår i: Physics Letters B. - elsevier : Elsevier BV. - 0370-2693 .- 1873-2445. ; 668:4, s. 258-262
  • Tidskriftsartikel (refereegranskat)abstract
    • The tensor polarisation of omega mesons produced in the pd -> He-3 omega reaction has been studied at two energies near threshold. The 3 He nuclei were detected in coincidence with the pi(0)pi(+)pi(-) or pi(0)gamma decay products of the omega. in contrast to the case of phi-meson production, the omega mesons are found to be unpolarised. This brings into question the applicability of the Okubo-Zweig-lizuka rule when comparing the production of vector mesons in low energy hadronic reactions.
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27.
  • Schönning, Karin, et al. (författare)
  • The pd →3Heηπ0 reaction at Tp = 1450 MeV
  • 2010
  • Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 685:1, s. 33-37
  • Tidskriftsartikel (refereegranskat)abstract
    • The cross section for the pd→3Heηπ0 reaction has been measured at a beam energy of 1450 MeV using the WASA detector at the CELSIUS storage ring and detecting one 3He and four photons from the decays of the two mesons. The data indicate that the production mechanism involves the formation of the Δ(1232) isobar. Although the beam energy does not allow the full peak of this resonance to be seen, the invariant masses of all three pairs of final particles are well reproduce dby a phase space Monte Carlo simulation weighted with the p-wave factor of the square of the π0 momentum in the 3He π0 system.
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28.
  • Adlarson, Patrik, et al. (författare)
  • Backward single-pion production in the pd -> He-3 pi(0)reaction with WASA-at-COSY
  • 2018
  • Ingår i: European Physical Journal A. - : SPRINGER. - 1434-6001 .- 1434-601X. ; 54:9
  • Tidskriftsartikel (refereegranskat)abstract
    • New data on the production of single neutral pions in the pd -> He-3 pi(0) reaction are presented. For fifteen proton beam momenta between p(p) = 1.60GeV/c and p(p) = 1.74 GeV/c, differential cross sections are determined over a large fraction of the backward hemisphere. Since the only previous systematic measurements of single-pion production at these energies were made in collinear kinematics, the present work constitutes a significant extension of the current knowledge on this reaction. Even this far above the production threshold, significant changes are found in the behaviour of the angular distributions over small intervals in beam momentum.
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29.
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30.
  • Boudard, A, et al. (författare)
  • Triplet np final state interactions at large momentum transfers
  • 1996
  • Ingår i: PHYSICS LETTERS B. - : ELSEVIER SCIENCE BV. - 0370-2693. ; 389:3, s. 440-444
  • Tidskriftsartikel (refereegranskat)abstract
    • Using the simple relation between the np scattering and bound state wave functions, the spin-triplet contributions to the pp --> pi(+)(pn) and backward dp --> p(pn) reactions are estimated for low np excitation energies. The good agreement with the pion p
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31.
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32.
  • Dobrokhotov, D, et al. (författare)
  • Has charge symmetry breaking been observed in the dd ->alpha pi(0) reaction?
  • 1999
  • Ingår i: PHYSICAL REVIEW LETTERS. - : AMERICAN PHYSICAL SOC. - 0031-9007. ; 83:25, s. 5246-5249
  • Tidskriftsartikel (refereegranskat)abstract
    • Estimates are made of the dd --> alpha gamma gamma production cross sections in a model where each neutron-proton pair in the beam and target initiates an np --> d gamma reaction. This approach, which successfully reproduces observables in two-pion produc
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33.
  • Faldt, Goran, et al. (författare)
  • A comparison of np -> d eta and np -> np eta production rates
  • 1996
  • Ingår i: NUCLEAR PHYSICS A. - : ELSEVIER SCIENCE BV. - 0375-9474. ; 604:4, s. 441-454
  • Tidskriftsartikel (refereegranskat)abstract
    • It is shown that in the impulse approximation the ratio of the near-threshold np --> {np}(I=0) eta to np --> d eta production rates depends weakly upon the form of the production operator and can be estimated using low-energy neutron-proton dynamics. The
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34.
  • Faldt, Goran, et al. (författare)
  • Bound and unbound wave functions at short distances
  • 1998
  • Ingår i: AMERICAN JOURNAL OF PHYSICS. - : AMER INST PHYSICS. - 0002-9505. ; 66:10, s. 876-881
  • Tidskriftsartikel (refereegranskat)abstract
    • There exists a simple relationship between a quantum-mechanical bound-state wave function and that of nearby scattering states, when the scattering energy is extrapolated to that of the bound state. This relationship is demonstrated numerically for the ca
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35.
  • Faldt, Goran, et al. (författare)
  • Bound state and continuum production in large momentum transfer reactions
  • 1996
  • Ingår i: PHYSICS LETTERS B. - : ELSEVIER SCIENCE BV. - 0370-2693. ; 382:3, s. 209-213
  • Tidskriftsartikel (refereegranskat)abstract
    • The cross sections for pp --> pn pi(+) and pd --> pd pi(0) are related to those for the corresponding reactions producing bound deuterons and He-3's respectively. The large momentum transfers in the reactions involve short range operators and under these
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36.
  • Faldt, Goran, et al. (författare)
  • Comparison of the near-threshold production of eta- and K-mesons in proton-proton collisions
  • 1997
  • Ingår i: ZEITSCHRIFT FUR PHYSIK A-HADRONS AND NUCLEI. - : SPRINGER VERLAG. - 0939-7922. ; 357:3, s. 241-243
  • Tidskriftsartikel (refereegranskat)abstract
    • The pp --> pp eta and pp --> p Lambda K+ reactions near threshold are dominated by the first and second S-11 resonance respectively. It is shown that a one-pion-exchange model exciting these isobars reproduces well the ratio of the production cross sectio
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37.
  • Faldt, Goran, et al. (författare)
  • Cross section and analyzing power of (p)over-right-arrow-p->pn pi(+) near threshold
  • 1997
  • Ingår i: PHYSICAL REVIEW C-NUCLEAR PHYSICS. - : AMER INST PHYSICS. - 0556-2813. ; 56:4, s. 2067-2073
  • Tidskriftsartikel (refereegranskat)abstract
    • The cross section and analyzing power of the (p)-over-right-arrow-p-->pn pi(+) reaction near threshold are estimated in terms of data obtained from the (p)-over-right-arrow-p-->d pi(+) and pp-->pp pi(0) reactions. A simple final state interaction theory i
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38.
  • Faldt, G, et al. (författare)
  • Pion production in the d(4)He -> Li-6 *pi(0) reaction near threshold
  • 2000
  • Ingår i: PHYSICS LETTERS B. - : ELSEVIER SCIENCE BV. - 0370-2693. ; 486:1-2, s. 67-70
  • Tidskriftsartikel (refereegranskat)abstract
    • The cross section for d(4)-He --> 6Li(3.56)* pi(0) is estimated very close to threshold in a model where the dp --> He-3 pi(0) reaction is assumed to occur on one of the target nucleons. The calculation reproduces the observed strong angular dependence, a
  •  
39.
  • Faldt, G, et al. (författare)
  • Production of isoscalar pion pairs in the pd -> He-3 pi pi reaction near threshold
  • 2000
  • Ingår i: PHYSICS LETTERS B. - : ELSEVIER SCIENCE BV. - 0370-2693. ; 496:3-4, s. 185-189
  • Tidskriftsartikel (refereegranskat)abstract
    • The production near threshold of isoscalar pion pairs in the pd -> He-3(pi pi)(0) reaction is estimated in a two-step model which successfully describes the production of eta, omega and eta' mesons. A virtual pion beam, generated through an NN -> d pi rea
  •  
40.
  • Faldt, Goran, et al. (författare)
  • Scattering wave functions at bound state poles
  • 1997
  • Ingår i: PHYSICA SCRIPTA. - : ROYAL SWEDISH ACAD SCIENCES. - 0281-1847. ; 56:6, s. 566-570
  • Tidskriftsartikel (refereegranskat)abstract
    • The normalization relation between the bound and scattering S-state wave functions, extrapolated to the bound state pole, is derived from the Schrodinger equation. It is shown that, unlike previous work, the result does not depend on the details of the po
  •  
41.
  • Faldt, Goran, et al. (författare)
  • The dd->He-4 eta reaction near threshold
  • 1996
  • Ingår i: NUCLEAR PHYSICS A. - : ELSEVIER SCIENCE BV. ; 596:3-4, s. 488-502
  • Tidskriftsartikel (refereegranskat)abstract
    • The cross section for the reaction dd --> He-4 eta close to threshold is estimated in a two-step model, similar to that which successfully describes near-threshold pd --> He-3 eta production. A pi-meson, created in a dp --> He-3 pi(0) process on one nucle
  •  
42.
  • FALDT, Goran, et al. (författare)
  • THE REACTION PD-]HE-3-ETA NEAR-THRESHOLD
  • 1995
  • Ingår i: NUCLEAR PHYSICS A. - : ELSEVIER SCIENCE BV. - 0375-9474. ; 587:4, s. 769-786
  • Tidskriftsartikel (refereegranskat)abstract
    • The cross section and deuteron tenser analysing power of the reaction pd-->He-3 eta are studied near threshold in a two-step model, where a pion beam, created in a NN-->d pi reaction on one of the nucleons in the target deuteron, is converted into an eta-
  •  
43.
  • FALDT, Goran, et al. (författare)
  • THRESHOLD PRODUCTION OF HEAVY MESONS IN THE PD-](3)HEX(0) REACTION
  • 1995
  • Ingår i: PHYSICS LETTERS B. - : ELSEVIER SCIENCE BV. - 0370-2693. ; 354:1-2, s. 20-23
  • Tidskriftsartikel (refereegranskat)abstract
    • The threshold production rates for isoscalar mesons X(0) formed through the pd --> (3)HeX(0) reaction are estimated in a two-step model. A virtual pion beam, produced in an NN --> d pi reaction on one of the nucleons in the target deuteron, is converted i
  •  
44.
  • Fäldt, Göran, et al. (författare)
  • Comparison of the pp → π+pn and pp → π+d production rates
  • 2017
  • Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 770, s. 146-148
  • Tidskriftsartikel (refereegranskat)abstract
    • Fully constrained bubble chamber data on the pp -> pi(+)pn and pp -> pi(+)d reactions are used to investigate the ratio of the counting rates for the two processes at low pn excitation energies. Whereas the ratio is in tolerable agreement with that found in a high resolution spectrometer experiment, the angular distribution in the final pn rest frame shows that the deviation from the predictions of final state interaction theory must originate primarily from higher partial waves in the pn system. These considerations might also be significant for the determination of the S -wave Ap scattering length from data on the pp -> K+Lambda p reaction.
  •  
45.
  • Fäldt, Göran, et al. (författare)
  • Estimation of the ratio of the pn -> pn pi(0)pi(0)/pn -> d pi(0)pi(0) cross sections
  • 2011
  • Ingår i: Physics Letters B. - : Elsevier BV. - 0370-2693 .- 1873-2445. ; 701:5, s. 619-622
  • Tidskriftsartikel (refereegranskat)abstract
    • Evidence has recently been presented for the existence of a dibaryon of mass 2380 MeV/c(2) and width 70 MeV/c(2), which decays strongly into the d pi(0)pi(0) channel [M. Bashkanov, et al., Phys. Rev. Lett. 102 (2009) 052301; P. Adlarson, et al., arXiv:1104.0123]. The decay rate of such a hypothesised dibaryon into the {pn}i=0 pi(0)pi(0) channel is estimated in a weakly model-dependent way by using final state interaction theory. It is shown that, if the resonance exists, it should show up as strongly in this channel as in d pi(0)pi(0). The sum of the two decay modes would saturate most of the inelasticity predicted in the relevant partial waves in the 2380 MeV/c(2) region.
  •  
46.
  • Fäldt, Göran, et al. (författare)
  • Extraction of parameters from final state interactions
  • 2017
  • Ingår i: PHYSICAL REVIEW C. - : AMER PHYSICAL SOC. - 2469-9985. ; 95:2
  • Forskningsöversikt (refereegranskat)abstract
    • It is argued that final state enhancements in production reactions at large momentum transfers, such as pp -> K+ Lambda p, are primarily sensitive to the position of a virtual bound state pole in the Lambda p system rather than the Lambda p scattering length and effective range. These arguments are supported by a study of the dispersion relation derived to describe such processes as a function of the cut-off energy. This shows that the position of the virtual bound state is independent of the cut-off energy.
  •  
47.
  • Fäldt, Göran, et al. (författare)
  • Phenomenological study of the pp -> pi(+) pn reaction
  • 2018
  • Ingår i: Physical Review C. - : AMER PHYSICAL SOC. - 2469-9985 .- 2469-9993. ; 97:2
  • Tidskriftsartikel (refereegranskat)abstract
    • Fully constrained bubble chamber data on the pp -> pi(+) pn and pp -> pi(+) d reactions are used to investigate the ratio of the counting rates for the two processes as function of the pn excitation energy Q. Though it is important to include effects associated with the p-wave nature of pion production, the data are insufficient to establish unambiguously the dependence on Q. The angular distributions show the presence of higher partial waves which seem to be anomalously large at small Q. The dispersion relation method to determine scattering lengths is extended to encompass cases where, as for the pp -> pi(+) pn reaction, there is a bound state and, in a test example, it is shown that the values deduced for the low-energy neutron-proton scattering parameters are significantly influenced by the pion p-wave behavior.
  •  
48.
  • Gardestig, Anders, et al. (författare)
  • An explanation of the ABC enhancement in the dd ->alpha X reaction at intermediate energies
  • 1998
  • Ingår i: PHYSICS LETTERS B. - : ELSEVIER SCIENCE BV. - 0370-2693. ; 421:1-4, s. 41-45
  • Tidskriftsartikel (refereegranskat)abstract
    • The dd --> alpha X reaction is studied in a model where each pair of nucleons in the projectile and target deuterons undergoes pion production through the NN --> d pi reaction. The condition that the two deuterons fuse to form an alpha-particle then leads
  •  
49.
  • Gommenginger, Christine, et al. (författare)
  • SEASTAR: A mission to study ocean submesoscale dynamics and small-scale atmosphere-ocean processes in coastal, shelf and polar seas
  • 2019
  • Ingår i: Frontiers in Marine Science. - : Frontiers Media SA. - 2296-7745. ; 6:JUL
  • Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
    • High-resolution satellite images of ocean color and sea surface temperature reveal an abundance of ocean fronts, vortices and filaments at scales below 10 km but measurements of ocean surface dynamics at these scales are rare. There is increasing recognition of the role played by small scale ocean processes in ocean-atmosphere coupling, upper-ocean mixing and ocean vertical transports, with advanced numerical models and in situ observations highlighting fundamental changes in dynamics when scales reach 1 km. Numerous scientific publications highlight the global impact of small oceanic scales on marine ecosystems, operational forecasts and long-term climate projections through strong ageostrophic circulations, large vertical ocean velocities and mixed layer re-stratification. Small-scale processes particularly dominate in coastal, shelf and polar seas where they mediate important exchanges between land, ocean, atmosphere and the cryosphere e.g. freshwater, pollutants. As numerical models continue to evolve towards finer spatial resolution and increasingly complex coupled atmosphere-wave-ice-ocean systems, modern observing capability lags behind, unable to deliver the high-resolution synoptic measurements of total currents, wind vectors and waves needed to advance understanding, develop better parameterizations and improve model validations, forecasts and projections. SEASTAR is a satellite mission concept that proposes to directly address this critical observational gap with synoptic two-dimensional imaging of total ocean surface current vectors and wind vectors at 1 km resolution and coincident directional wave spectra. Based on major recent advances in squinted along-track Synthetic Aperture Radar interferometry, SEASTAR is an innovative, mature concept with unique demonstrated capabilities, seeking to proceed towards spaceborne implementation within Europe and beyond.
  •  
50.
  • Hibou, F, et al. (författare)
  • Comparison of eta and eta ' production in the pp -> pp eta(eta ') reactions near threshold
  • 1998
  • Ingår i: PHYSICS LETTERS B. - : ELSEVIER SCIENCE BV. - 0370-2693. ; 438:1-2, s. 41-46
  • Tidskriftsartikel (refereegranskat)abstract
    • The total cross section of the pp --> pp eta' reaction has been measured at two energies near threshold by detecting the final protons in a magnetic spectrometer. The values obtained are about a factor of 70 less than for the corresponding eta production,
  •  
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