Browsing by Subject "ISOTOPES"

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  • Oinonen, Markku; Alenius, Teija; Arppe, Laura; Bocherens, Hervé; Etu-Sihvola, Heli; Helama, Samuli; Huhtamaa, Heli; Lahtinen, Maria; Mannermaa, Kristiina; Onkamo, Päivi; Palo, Jukka; Sajantila, Antti; Salo, Kati; Sundell, Tarja; Vanhanen, Santeri; Wessman, Anna (2020)
    Levanluhta is a unique archaeological site with the remains of nearly a hundred Iron Age individuals found from a water burial in Ostrobothnia, Finland. The strongest climatic downturn of the Common Era, resembling the great Fimbulvinter in Norse mythology, hit these people during the 6th century AD. This study establishes chronological, dietary, and livelihood synthesis on this population based on stable carbon and nitrogen isotopic and radiocarbon analyses on human remains, supported by multidisciplinary evidence. Extraordinarily broad stable isotopic distribution is observed, indicating three subgroups with distinct dietary habits spanning four centuries. This emphasizes the versatile livelihoods practiced at this boundary of marine, freshwater, and terrestrial ecosystems. While the impact of the prolonged cold darkness of the 6th century was devastating for European communities relying on cultivation, the broad range of livelihoods provided resilience for the Levanluhta people to overcome the abrupt climatic decline.
  • Caballero-Folch, R.; Dillmann, I.; Agramunt, J.; Tain, J. L.; Algora, A.; Äystö, J.; Calvino, F.; Canete, L.; Cortes, G.; Domingo-Pardo, C.; Eronen, T.; Ganioglu, E.; Gelletly, W.; Gorelov, D.; Guadilla, V.; Hakala, J.; Jokinen, A.; Kankainen, A.; Kolhinen, V. S; Koponen, J.; Marta, M.; Mendoza, E.; Montaner-Piza, A.; Moore, I.; Nobs, C. R.; Orrigo, S. E. A.; Penttilä, H.; Pohjalainen, J.; Reinikainen, J.; Riego, A.; Rinta-Antila, S.; Rubio, B.; Salvador-Castineira, P.; Simutkin, V.; Tarifeno-Saldivia, A.; Tolosa-Delgado, A.; Vos, A. (2018)
    Background: beta-delayed multiple neutron emission has been observed for some nuclei with A 100 to test the predictions of theoretical models and simulation tools for the decays of heavy nuclei in the region of very neutron-rich nuclei. In addition the decay properties of these nuclei are fundamental for the understanding of astrophysical nucleosynthesis processes such as the r-process and safety inputs for nuclear reactors. Purpose: To determine for the first time the two-neutron branching ratio the P-2n value for Sb-136 through a direct neutron measurement and to provide precise P-1n values for Sb-136 and Te-136. Method: A pure beam of each isotope of interest was provided by the JYFLTRAP Penning trap at the Ion Guide Isotope Separator On-Line (IGISOL) facility of the University of Jyvaskyla Finland. The purified ions were implanted into a moving tape at the end of the beam line. The detection setup consisted of a plastic scintillator placed right behind the implantation point after the tape to register the beta decays and the BELEN detector based on neutron counters embedded in a polyethylene matrix. The analysis was based on the study of the beta- and neutron-growth-and-decay curves and the beta-one-neutron and beta-two-neutron time correlations which allowed us the determination of the neutron branching ratios. Results: The P-2n value of Sb-136 was found to be 0.14(3)% and the measured P-1n values for Sb-136 and Te-136 were found to be 32.2(15)% and 1.47(6)% respectively. Conclusions: The measured P-2n value is a factor 44 smaller than predicted by the finite-range droplet model plus the quasiparticle random-phase approximation (FRDM+QRPA) model used for r-process calculations.
  • Lica, R.; Rotaru, F.; Borge, M. J. G.; Grevy, S.; Negoita, F.; Poves, A.; Sorlin, O.; Andreyev, A. N.; Borcea, R.; Costache, C.; De Witte, H.; Fraile, L. M.; Greenlees, P. T.; Huyse, M.; Ionescu, A.; Kisyov, S.; Konki, J.; Lazarus, I.; Madurga, M.; Marginean, N.; Marginean, R.; Mihai, C.; Mihai, R. E.; Negret, A.; Page, R. D.; Pakarinen, J.; Pascu, S.; Pucknell, V.; Rahkila, P.; Rapisarda, E.; Serban, A.; Sotty, C. O.; Stan, L.; Stanoiu, M.; Tengblad, O.; Turturica, A.; Van Duppen, P.; Wadsworth, R.; Warr, N.; IDS Collaboration (2017)
    The beta(-) decay of Mg-34 was used to study the Al-34 nucleus through. spectroscopy at the Isotope Separator On-Line facility of CERN. Previous studies identified two beta-decaying states in Al-34 having spin-parity assignments J(pi) = 4(-) dominated by the normal configuration pi(d(5/2))(-1)circle times nu(f(7/2)) and J(pi) = 1(+) by the intruder configuration pi(d(5/2))(-1) circle times nu(d(3/2))(-1) (f(7/2))(2). Their unknown ordering and relative energy have been the subject of debate for the placement of Al-34 inside or outside the N = 20 "island of inversion." We report here that the 1(+) intruder lies only 46.6 keV above the 4(-) ground state. In addition, a new half-life of T-1/2 = 44.9(4) ms, that is twice as long as the previously measured 20(10) ms, has been determined for Mg-34. Large-scale shell-model calculations with the recently developed SDPF-U-MIX interaction are compared with the new data and used to interpret the mechanisms at play at the very border of the N = 20 island of inversion.
  • Konki, J.; Sulignano, B.; Greenlees, P. T.; Theisen, Ch.; Auranen, K.; Badran, H.; Briselet, R.; Cox, D. M.; Bisso, F. Defranchi; Dobaczewski, J.; Grahn, T.; Herzan, A.; Herzberg, R. -D.; Julin, R.; Juutinen, S.; Khuyagbaatar, J.; Leino, M.; Lightfoot, A.; Pakarinen, J.; Papadakis, P.; Partanen, J.; Rahkila, P.; Sandzelius, M.; Saren, J.; Scholey, C.; Shi, Y.; Smolen, M.; Sorri, J.; Stolze, S.; Uusitalo, J. (2018)
    The ground-state rotational band of the neutron-deficient californium (Z = 98) isotope 244Cf was identified for the first time and measured up to a tentative spin and parity of I I-pi = 20(+). The observation of the rotational band indicates that the nucleus is deformed. The kinematic and dynamic moments of inertia were deduced from the measured gamma-ray transition energies. The behavior of the dynamic moment of inertia revealed an up-bend due to a possible alignment of coupled nucleons in high-j orbitals starting at a rotational frequency of about (h) over bar (omega) = 0.20 MeV. The results were compared with the systematic behavior of the even-even N = 146 isotones as well as with available theoretical calculations that have been performed for nuclei in the region.
  • Perez-Loureiro, D.; Benlliure, J.; Diaz-Cortes, J.; Rodriguez-Sanchez, J. L.; Alvarez-Pol, H.; Blank, B.; Casarejos, E.; Dragosavac, D.; Foehr, C.; Gascon, M.; Gawlikowicz, W.; Heinz, A.; Helariutta, K.; Kelic-Heil, A.; Lukic, S.; Montes, F.; Pienkowski, L.; Schmidt, K-H; Staniou, M.; Subotic, K.; Suemmerer, K.; Taieb, J.; Trzcinska, A. (2019)
    The production cross sections of neutron-rich fission residues in reactions induced by U-238 projectiles at 950A MeV impinging on Pb and Be targets are investigated at the Fragment Separator at GSI. These two targets allow us to investigate fission processes induced by two reaction mechanisms, Coulomb and nuclear excitations, and to study the role of these mechanisms in the neutron excess of the final fragments.
  • Väre, Tiina; Lipkin, Sanna; Suomela, Jenni A.; Vajanto, Krista (2021)
    Vicar Nikolaus Rungius's (ca. 1560-1629) mummified remains have been the subject of research that has provided a wide variety of information on his life. This article examines the ways Rungius's health and lifestyle highlight his status as a vicar, and this status is visible in his burial and funerary clothing. He was a relatively large man for his time. CT scans even include indications of certain conditions related to being overweight. Likewise, stable-isotope analyses of his nail keratin support the hypothesis that he was consuming a rather heavy, protein-rich diet. Given his status as the vicar of Kemi parish in northern Finland, he likely made sumptuous use of the rich local natural resources of fish, game, and domestic animals as part of his regular diet. In addition to his diet and health, the vicar's high-quality clothes, while fragmentary, also open an avenue to extend the exploration of his social status and wealth.
  • Sundholm, Dage; Pyykkö, Pekka (2018)
    New standard values -116(2) mb and 76(3) mb are suggested for the nuclear quadrupole moments (Q) of the Ar-39 and Ar-37 nuclei, respectively. The Q values were obtained by combining optical measurements of the quadrupole coupling constant (B or eqQ/h) of the 3s(2)3p(5)4s[3/2](2) (P-3(o)) and 3s(2)3p(5)4p[5/2](3) (D-3(e)) states of argon with large scale numerical complete active space self-consistent field and restricted active space self-consistent field calculations of the electric field gradient at the nucleus (q) using the LUCAS code, which is a finite-element based multiconfiguration Hartree-Fock program for atomic structure calculations. Q(Ar-39(18)) = -116(2) mb
  • Åberg, Susanne; Korkka-Niemi, Kirsti; Rautio, Anne Brita Kristina; Åberg, Annika (2022)
    Study region Northern Finland. Study focus This study examined long-term (decade-scale) hydrological and ecological consequences of dam construction and subsequent river regulation on the environmentally protected Viiankiaapa mire. Pre-regulation floods affected the hydrology of the riverbanks and the Viiankiaapa mire, which contain habitats of flood-dependent or groundwater-influenced ecosystems. Groundwater discharge and flow patterns and pre-regulation flood coverage were simulated to investigate the impact of river regulation on the mire area. New hydrological insights for the region The flood models indicate that regular flooding covered the westernmost part of the mire before the regulation. Groundwater modelling suggests that the regulation has raised the locations of springs in the river shore, reduced the hydraulic gradient towards the river, raised the groundwater table in the river banks and the western part of the Viiankiaapa mire, and increased groundwater discharge in the mire. The groundwater flow models and the stable isotopic composition of water indicate that the constructed dam changed the groundwater flow directions close to dam. The ecological effects of regulation were mixed: the studied flood-dependent plant species declined due to the reduction in floods after regulation. Conversely, the occurrence of Hamatocaulis vernicosus and Hamatocaulis lapponicus appears to be related to the high water table and groundwater discharge areas in the mire, suggesting suitable habitat for these species may have expanded after the regulation.
  • Gennaretti, Fabio; Boucher, Etienne; Nicault, Antoine; Gea-Izquierdo, Guillermo; Arseneault, Dominique; Berninger, Frank; Savard, Martine M.; Begin, Christian; Guiot, Joel (2018)
    The Tambora eruption (1815 AD) was one of the major eruptions of the last two millennia and has no equivalents over the last two centuries. Here, we collected an extensive network of early meteorological time series, climate simulation data and numerous, well-replicated proxy records from Eastern Canada to analyze the strength and the persistence of the Tambora impact on the regional climate and forest processes. Our results show that the Tambora impacts on the terrestrial biosphere were stronger than previously thought, and not only affected tree growth and carbon uptake for a longer period than registered in the regional climate, but also determined forest demography and structure. Increased tree mortality, four times higher than the background level, indicates that the Tambora climatic impact propagated to influence the structure of the North American taiga for several decades. We also show that the Tambora signal is more persistent in observed data (temperature, river ice dynamics, forest growth, tree mortality) than in simulated ones (climate and forest-growth simulations), indicating that our understanding of the mechanisms amplifying volcanic perturbations on climates and ecosystems is still limited, notably in the North American taiga.