نتایج جستجو برای: isotopes
تعداد نتایج: 24561 فیلتر نتایج به سال:
Stable isotopes of carbon are commonly used to characterize dietary preferences in animals. Because turnover rates of carbon isotopes are related to metabolic rate, we wanted to determine the rates at which carbon isotopes are exchanged in tissues of two species of nectar-feeding bats (Leptonycteris curasoae and Glossophaga soricina), both of which have relatively high mass-specific metabolic r...
Currently, 31 dysprosium, 32 holmium, 32 erbium, 33 thulium and 31 ytterbium isotopes have been observed and the discovery of these isotopes is discussed here. For each isotope a brief synopsis of the first refereed publication, including the production and identification method, is presented. ∗Corresponding author. Email address: [email protected] (M. Thoennessen) Preprint submitted to ...
Currently, thirty-nine astatine, thirty-nine radon,??? isotopes have so far been observed; the discovery of these isotopes is discussed. For each isotope a brief summary of the first refereed publication, including the production and identification method, is presented. ∗Corresponding author. Email address: [email protected] (M. Thoennessen) Preprint submitted to Atomic Data and Nuclear ...
The sulfur isotopic composition of dissolved sulfate in seawater has varied through time. Distinct variations and relatively high rates of change characterize certain time intervals. This allows for dating and correlation of sediments using sulfur isotopes. The variation in sulfur isotopes and the potential stratigraphic resolution of this isotope system is discussed and graphically displayed.
When attempting to determine the diet of wild animals, a limited number of techniques currently exist. Often, biologists look at the stomach contents or feces of an animal, if they cannot observe what it is eating directly. However, these techniques often cannot be used with reptiles because they may not eat often or may have an empty stomach when the contents of their stomach are examined. Man...
Fluxes of carbon, nitrogen, and water between ecosystem components and organisms have great impacts across levels of biological organization. Although much progress has been made in tracing carbon and nitrogen, difficulty remains in tracing water sources from the ecosystem to animals and among animals (the "water web"). Naturally occurring, non-radioactive isotopes of hydrogen and oxygen in wat...
Melting of mafic veins in a marble-cake mantle may play an important role in generating isotopic and chemical heterogeneities in mid-ocean ridge and ocean island basalts. Mafic veins have lower solidi than mantle peridotite and will be preferentially sampled during partial melting, particularly at low melt fractions. However, the abundance of mafic components in the mantle or their role during ...
We discuss implications of recent precision measurements for the Rh proton separation energy for the production of the lightest molybdenum isotopes in proton-rich type II supernova ejecta. It has recently been shown that a novel neutrino-induced process makes these ejecta a promising site for the production of the light molybdenum isotopes and other “p-nuclei” with atomic mass near 100. The ori...
BACKGROUND One of the limiting factors in achieving the best spatial resolution in positron emission tomography (PET), especially in small-animal PET, is the positron range associated with the decay of nuclides, and usual PET image reconstruction algorithms do not provide a correction for the positron range. This work presents initial results obtained with the maximum a posteriori (MAP) algorit...
this paper presents the new geochemical isotopes sr and nd, and the mineralization data for the south neyshabour volcanic rocks located in ne iran. based on the chemical classifications, the studied rocks are basaltic trachy andesite, trachy andesite, trachyte, and trachy dacite in composition. all the analyzed volcanic rocks display enrichment in light rare earth elements (lree) relative to th...
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