Fecundity is affected by changes in the nutritional and energetic environment, as a result of changes in acquisition, assimilation, or allocation of macro-nutrients and micro-nutrients. Stable isotopes of carbon and nitrogen offer a window into the processes underlying these changes. In insects that feed on nectar as adults, carbon isotopes can be used to trace allocation of carbon to eggs from...

The separation of isotopes in space and time by gas-surface atomic diffraction is presented as a new means for isotopic enrichment. A supersonic beam of natural abundance neon is scattered from a periodic surface of methyl-terminated silicon, with the ^{20}Ne and ^{22}Ne isotopes scattering into unique diffraction channels. Under the experimental conditions presented in this Letter, a single pa...

To assess the contribution of accumulated winter precipitation and glacial meltwater to the recharge of deep ground water flow systems in fracture crystalline rocks, measurements of environmental isotope ratios, hydrochemical composition, and in situ parameters of ground water were performed in a deep tunnel. The measurements demonstrate the significance of these ground water recharge component...

An outstanding feature of mass spectrometry is the possibility of determining exact masses and accurate abundances of stable and unstable isotopes with high precision. The importance of isotope ratio measurements by mass spectrometry has grown in the last few years due to a significant improvement of instrumentation with respect to sensitivity, detection limits, precision and accuracy, whereby ...

Neutron-rich Zr and Mo isotopes were populated as fission fragments produced by the 238Usa, fd fusionfission reaction. The level schemes of these nuclei have been extended beyond the first band crossing region, which can be ascribed to the h11/2 neutron pair alignment. The spin alignment and signature splitting for the nh11/2 orbitals in term of triaxiality is addressed. The crossing frequency ...

Alpha spectrometry is the most commonly used analytical tool for the determination of Pu, Am, Pa, U and Th long live radionuclides. Thermal ionization mass spectrometry (TIMS) and acceleration mass spectrometry (AMS) are also still considered as primary methods for the determination of their isotope ratios. Spectrometers with plasma ion sources now offer another efficient alternative method wit...

The uranium concentration in 59 samples of bottled and tap water, mainly from northern Italy, was measured by different techniques. Results obtained by inductively coupled plasma mass spectrometry (ICP-MS), semiconductor alpha spectrometry and low level liquid scintillation counting with alpha/beta discrimination (LSC) have been compared. High resolution gamma spectrometry and semiconductor alp...

a three-step selective photo-ionization for gd155 and gd157 isotopes by pulsed laser wasevaluated numerically. due to large thermal neutron absorption cross sections, these two isotopes innatural gadolinium are good candidates as burnable poison to control reactivity early in the fuel cycleand allow extended fuel burn up. rate equations have been used to calculate the dynamics of the isotopepop...

for more than half a century isotopes have been employed as a powerful tool in studying various aspects of water resources in a largenumber of countries. however, in developing countries like iran the application of such techniques is in its infancy. the first research iniran was carried out in 1975 to identify the source of saline groundwaters in south iran, and the first national conference o...

The stochastic and infrequent nature of long-distance dispersal often makes it difficult to detect. We quantified the frequency, distance, and timing of long-distance dispersal in a nonmigratory, secretive wetland bird, the California Black Rail (Laterallus jamaicensis coturniculus), between an inland and a coastal metapopulation separated by greater than 100 km. Using 15 microsatellites in con...