نتایج جستجو برای: environmental isotopes
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Stable isotopes and their potential for detecting various and complex ecosystem processes are attracting an increasing number of scientists. Progress is challenging, particularly under global change scenarios, but some established views have been challenged. The IX meeting of the Spanish Association of Terrestrial Ecology (AAET, Ubeda, 18-22 October 2009) hosted a symposium on the ecology of st...
We have measured the hyperfine splitting of the 7P_{1/2} state at the 100 ppm level in Fr isotopes (^{206g,206m,207,209,213,221}Fr) near the closed neutron shell (N=126 in ^{213}Fr). The measurements in five isotopes and a nuclear isomeric state of francium, combined with previous determinations of the 7S_{1/2} splittings, reveal the spatial distribution of the nuclear magnetization, i.e., the ...
background: the thyroid gland absorbs nearly all the iodine in the blood, independently of its isotopic composition. when a large enough activity of radioactive iodine like 131i, 132i, 133i is taken into the body, it can destroy the healthy thyroid gland cells as well as the cancer’s cells. in fact, as it is well known, some isotopes of iodine are used not only for acquiring thyroid images but ...
Light isotopes separation, such as (3)He/(4)He, H2/D2, H2/T2, etc., is crucial for various advanced technologies including isotope labeling, nuclear weapons, cryogenics and power generation. However, their nearly identical chemical properties made the separation challenging. The low productivity of the present isotopes separation approaches hinders the relevant applications. An efficient membra...
Formation of anomalous isotope abundances in the atmospheres of chemically peculiar (CP) stars can be explained by light-induced drift (LID). This effect is additional to the radiative acceleration and appears due to systematic asymmetry of radiative flux in partly overlapping isotopic spectral line profiles. LID causes levitation of an isotope with a red-shifted spectral line and sinking of an...
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—Throughout the late Quaternary, the Sahul (Pleistocene Australia–New Guinea) vertebrate fauna was dominated by a diversity of large mammals, birds, and reptiles, commonly referred to as megafauna. Since ca. 450–400Ka, approximately 88 species disappeared in Sahul, including kangaroos exceeding 200kg in size, wombat-like animals the size of hippopotamuses, flightless birds, and giant monitor li...
The ability to separate isotopes by high-resolution ion mobility spectrometry techniques is considered as a direct means for determining mass at ambient pressures. Calculations of peak shapes from the transport equation show that it should be possible to separate isotopes for low-mass ions (<200) by utilizing heavy collision gases and high-resolution ion mobility analyzers. The mass accuracy as...
The Ilam Formation (Santonian-Campanian) is a unit of Bangestan Group, which is overlain on the Sarvak Formation in Tang E-Rashid area, Peyon Anticline (18.5 Km North of Izeh). Due to similar lithology, recognition of the exact boundary between Ilam and Sarvak Formations in the study area was difficult. Thus it is not possible to determine boundary between these two formations based on petrogra...
In order to investigate chlorine isotope behaviour, it was necessary to develop analytical methods and methods for data interpretation. The accuracy, precision and amount dependency of chlorine isotope ratio analyses performed with gas chromatography quadrupol mass-spectrometry (GC-qMS) were evaluated for two Agilent and Thermo instruments. The calibration of raw data to SMOC scale (Standard Me...
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