Search results for "ISOTOPES"
showing 10 items of 1216 documents
Lifetime measurement of the first excited 2+ state in 112Te
2015
The lifetime of the 2+ → 0+ g.s. transition in the neutron-deficicient nucleus 112Te has been measured for the first time using the DPUNS plunger and the recoil distance Doppler shift technique. The deduced value for the reduced transition probability is B(E2 :0+ g.s. → 2+) = 0.46 ± 0.04 e2b2, indicating that there is no unexpected enhancement of the B(E2 :0+ g.s. → 2+) values in Te isotopes below the midshell. The result is compared to and discussed in the framework of large-scale shell-model calculations. peerReviewed
First decay study of the very neutron-rich isotope 93Br
2001
The decay of the mass-separated, very neutron-rich isotope 93 Br has been studied by γ spectroscopy. A level scheme of its daughter 93 Kr has been constructed. Level energies, γ-ray branching ratios, and multipolarities suggest spins and parities which are in accord with a smooth systematics of the N = 57 isotones for Z <~ 4 0 , suggesting the N = 56 subshell closure still to be effective in Kr isotopes. So far, there is no indication of a progressive onset of deformation in neutron-rich Kr isotopes. peerReviewed
Diet composition and seasonal feeding patterns of a freshwater ringed seal (Pusa hispida saimensis)
2015
The Saimaa ringed seal (Pusa hispida saimensis) is one of the few freshwater seal populations worldwide. The major conservation issue of this critically endangered population is bycatch mortality. We used digestive tract content and stable isotopes (d13C and d15N) to estimate the diet and seasonal feeding patterns for gaining better understanding of the seals feeding habits and potential conservation implications. The diet was similar across age groups. Altogether 15 fish species were identified and the most important were smelt (Osmerus eperlanus), ruff (Gymnocephalus cernuus), perch (Perca fluviatilis), vendace (Coregonus albula) and cyprinids. The high d15N values suggested that the seal…
A stable isotope study of the hydrological and carbon cycle in meromictic lake, Lovojärvi
2012
Lake Lovojärvi, at its deepest point of 17.5 m, is permanently stratified forming two water layers. The mixolimnion (the upper layer, from 0 to 10 m depth) is affected by seasonal changes while the monimolimnion (bottom layer, from 10 to 17.5 m depth) does not mix and is not affected by seasonal changes. As a result, the lake stores large quantities of dissolved inorganic carbon and methane. I used a multiple stable isotope approach to gain insight into the carbon cycle and water balance of Lovojärvi. The δ18O and δ2H profiles reveal that at the 7 m depth in the mixolimnion, there is a sub-surface stream whose isotopic characteristics are similar to surface streams from a nearby mire, sugge…
Ontogenetic δ15N Trends and Multidecadal Variability in Shells of the Bivalve Mollusk, Arctica islandica
2021
Bulk stable nitrogen isotope values of the carbonate-bound organic matrix in bivalve shells (δ15NCBOM) are increasingly used to assess past food web dynamics, track anthropogenic nitrogen pollution and reconstruct hydrographic changes. However, it remains unresolved if the δ15NCBOM values are also affected by directed ontogenetic trends which can bias ecological and environmental interpretations. This very aspect is tested here with modern and fossil specimens of the long-lived ocean quahog, Arctica islandica, collected from different sites and water depths in the NE Atlantic Ocean. As demonstrated, δ15NCBOM values from the long chronologies show a general decrease through lifetime by −0.00…
High-resolution laser spectroscopy of long-lived plutonium isotopes
2017
Long-lived isotopes of plutonium were studied using two complementary techniques, high-resolution resonance ionisation spectroscopy (HR-RIS) and collinear laser spectroscopy (CLS). Isotope shifts have been measured on the $5f^67s^2\ ^7F_0 \rightarrow 5f^56d^27s\ (J=1)$ and $5f^67s^2\ ^7F_1 \rightarrow 5f^67s7p\ (J=2)$ atomic transitions using the HR-RIS method and the hyperfine factors have been extracted for the odd mass nuclei $^{239,241}$Pu. Collinear laser spectroscopy was performed on the $5f^67s\ ^8F_{1/2} \rightarrow J=1/2\; (27523.61\text{cm}^{-1})$ ionic transition with the hyperfine $A$ factors measured for $^{239}$Pu. Changes in mean-squared charge radii have been extracted and s…
The origin of heavy metals and radionuclides accumulated in the soil and biota samples collected in Svalbard, near Longyearbyen
2017
Heavy metals and radioactive compounds are potentially hazardous substances for plants, animals and humans in the Arctic. A good knowledge of the spatial variation of these substances in soil and primary producers, and their sources, is therefore essential. In the samples of lichen Thamnolia vermicularis, Salix polaris and Cassiope tetragona, and the soil samples collected in 2014 in Svalbard near Longyearbyen, the concentrations of the following heavy metals were determined: Mn, Ni, Cu, Zn, Cd, Pb and Hg, as well as the activity concentrations of the following: K-40, Cs-137, Pb-210, Pb-212, Bi-212, Bi-214, Pb-214, Ac-228, Th-231 and U-235 in the soil samples. The differences in the concent…
Preliminary results of studies on radioisotopes activity concentrations in vicinity of cement works
2012
W wielu miejscowościach znajdują się pozostałości po zakładach przemysłowych. Nawet jeśli taki teren został zrekultywowany, często obszary położone nieco dalej nie zostały przywrócone do pierwotnego stanu. Na takich terenach można spodziewać się istnienia podwyższonych stężeń różnych pierwiastków, w tym izotopów promieniotwórczych. Do badań pobrano próbki gleby na obszarze byłej cementowni „Piast”, znajdującej się w granicach miasta Opola oraz na obszarze pobliskich ogródków działkowych. W badanych próbkach stwierdzono obecność naturalnych izotopów promieniotwórczych oraz 137Cs. Największe aktywności wykazywały 40K oraz 137Cs. Aktywności naturalnych izotopów promieniotwórczych były znacznie…
IAEA Contribution to Nanosized Targeted Radiopharmaceuticals for Drug Delivery.
2022
The rapidly growing interest in the application of nanoscience in the future design of radiopharmaceuticals and the development of nanosized radiopharmaceuticals in the late 2000′s, resulted in the creation of a Coordinated Research Project (CRP) by the International Atomic Energy Agency (IAEA) in 2014. This CRP entitled ‘Nanosized delivery systems for radiopharmaceuticals’ involved a team of expert scientist from various member states. This team of scientists worked on a number of cutting-edge areas of nanoscience with a focus on developing well-defined, highly effective and site-specific delivery systems of radiopharmaceuticals. Specifically, focus areas of various teams of scientists com…
Chemical and isotopic characterization of rainwater in volcanic, urban and industrial areas of Sicily (Italy)
2021
The chemical composition of rainwater depends on (i) the dissolution of gases and particulate matter emitted by different sources, (ii) the chemical and physical reactions occurring during local and regional scale transport, and (iii) removal processes. The source of major and trace elements dissolved in rainwater can be both natural (e.g. sea salts, volcanic emissions, geogenic dust, biogenic material) and anthropogenic (e.g. industrial plants, vehicular traffic, domestic heating, vessel traffic). A group of trace elements has been recently brought to attention, especially for their possible environmental impacts, the Technology-critical elements (TCEs): Ga, Ge, In, Te, Nb, Ta, Tl, the Pla…