Results of two experiments with Yttrium-89 samples on U/Pb-assembly “Energy plus Transmutation” 1 are presented. The assembly is a lead cylindrical target (8.4 cm diameter, 45.6 cm length) with ...natural uranium blanket (206.4 kg). The lead target was irradiated with JINR Dubna NUCLOTRON with 1.60 and 2.52 GeV deuteron beam. The final purpose of the experiments was to measure neutron field inside the assembly. Yttrium-89 activation detectors were located throughout the entire U/Pb-assembly. Irradiated sample gamma activity was measured with HPGe spectrometer. The gamma spectra were analyzed and the net peak areas were calculated using the DEIMOS program 2. After short presentation of the activation results neutron spectrum determination method is proposed and its results presented. Assuming reaction model through compound nucleus and using some mathematical tricks Yttrium isotope “k ” production rate discrete formula
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$$I_k = N\int\limits_{E_{thr,k} }^\infty {\phi \left( E \right)\sigma _k \left( {E,E_{thr} } \right)} dE$$
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was transformed into Volterra's integral equation of the first kind and then solved. The method and its applicability still to be discussed. The results as the preliminary ones are for illustrative purpose only.
The experiment described in this communication is a part of the scientific program "Investigations of physical aspects of electronuclear method of energy production and transmutation of radioactive ...waste of atomic energetic using relativistic beams from the JINR Synchrophasotron/Nuclotron" - the project "Energy plus Transmutation". The performing of the first experiment at deuteron beam with energy 2.52 GeV at the electronuclear setup which consists of Pb-target with U-blanket (206.4 kg of natural uranium) and transmutation samples and its preliminary results are described. The hermetic samples of isotopes of I-129, Np-237, Pu-238 and Pu-239 which are produced in atomic reactors and industry setups which use nuclear materials and nuclear technologies were irradiated in the field of electronuclear neutrons produced in the Pb-target surrounded with the U-blanket setup "Energy plus transmutation". The estimations of its transmutations (radioecological aspect) were obtained in result of measurements of gamma activities of these samples. The information about space-energy distribution of neutrons in the volume of the Pb-target and the U-blanket was obtained with help of sets of activation threshold detectors (Al, V, Cu, Co, Y, In, I, Ta, Au, W, Bi and other), solid state nuclear track detectors, He-3 neutron detectors and nuclear emulsions. PUBLICATION ABSTRACT
The Eastern Pacific hawksbill sea turtle population is one of the most endangered of all sea turtle species. Here, we examine the foraging ecology of 47 hawksbill turtles (40.5–90.3 cm CCL, ...mean = 54.1 ± 10.1 cm) around Isla San José, Gulf of California, Mexico by integrating information from passive acoustic telemetry, behavior recordings, fecal analysis, and habitat surveys. Tagged hawkbill turtles exhibited high site fidelity over months and years (tracking duration 1–1490 days, mean = 255 ± 373 days) to the location and benthic habitat where individuals were initially caught. Diet was dominated by benthic invertebrates and algae including sponges, algae, tunicates, and mangrove roots. The mean percent cover of these benthic food items was significantly greater in the mangrove estuary than in adjacent rocky and sandy reef habitats. The Isla San José foraging ground is a high-use area for hawksbills and should be granted national protection status.
•Hawksbill turtles had limited movements and high site fidelity, over years, to the habitats where they were caught.•Mangrove estuaries provide greater food availability for foraging hawksbill sea turtles.•Invertebrates and algae growing on mangrove roots provide additional forage biomass for hawksbill sea turtles.•The Isla San José foraging ground is a high-use area for juvenile hawksbills in the Gulf of California, Mexico.•The foraging ground of Isla San José should be designated as a marine protected area.
Hawksbill turtles (n = 56) in a foraging ground around Isla San Jose, Gulf of California, Mexico, were caught, measured, and their skin and scutes sampled. Tissue samples from putative prey species ...were collected from observed hawksbill feeding areas in the foraging ground.
Measurements of each turtle's straight carapace length were used to estimate the average life stage of the population. Tissue samples were processed for stable carbon and nitrogen isotope analysis to estimate foraging habits of turtles in this location.
The majority (96.4%) of measured individuals' straight carapace length fell in the size range considered to be juveniles.
A Bayesian mixing model analysis of the δ13C and δ15N values of hawksbill skin and potential prey indicated that hawksbills consume primarily invertebrates and algae, with lesser contributions from seagrass and mangrove material.
There was a positive linear relationship between turtle size and the δ13C values from scute samples, and an increase in the δ13C values of five individuals recaptured in subsequent years suggested a potential location shift from a pelagic habitat in the turtles' post‐hatching, earliest juvenile years to the nearshore foraging area around Isla San Jose in their later juvenile years.
Extracellular matrix (ECM) of bone tissue is a typical composite system consisting of a mineral phase (hydroxyapatite HA—more precisely bone mineral is a hydroxyl-and calcium-decient, carbonated ...apatite) and an organic
phase (collagen and noncollagenous proteins such as osteocalcin, osteonectin, bone sialoprotein) (Boskey 2005). This composite ECM structure can be
described in terms of hierarchical levels of organization from nanometers,
through micrometers, and nally to millimeters scale range (Rho et al. 1998).
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