Archeological analysis of faunal remains and of lithic and bone tools has suggested that hunting of medium to large mammals was a major element of Neanderthal subsistence. Plant foods are almost invisible in the archeological record, and it is impossible to estimate accurately their dietary importance. However, stable isotope (delta(13)C and delta(15)N) analysis of mammal bone collagen provides...

The now arid Great Basin of western North America hosted expansive late Quaternary pluvial lakes, yet the climate forcings that sustained large ice age hydrologic variations remain controversial. Here we present a 175,000 year oxygen isotope record from precisely-dated speleothems that documents a previously unrecognized and highly sensitive link between Great Basin climate and orbital forcing....

The enzyme-substrate complex is inherently transient, rendering its detection difficult. In our framework designed for bisubstrate systems-isotope-labeled, activity-based identification and tracking (IsoLAIT)-the common substrate, such as S-adenosyl-l-methionine (AdoMet) for methyltransferases, is replaced by an analogue (e.g., S-adenosyl-l-vinthionine) that, as a probe, creates a tightly bound...

A year round study of photosynthesis and carbon isotope fractionation was conducted with plants of Opuntia phaeacantha Engelm. and Yucca baccata Torr. occurring in natural stands at elevations of 525, 970, 1450 and 1900 m. Plant water potentials and the daytime pattern of (14)CO(2) photosynthesis were similar for all cacti along the elevational gradient, despite significant differences in tempe...

An improved sample preparation procedure for trace-levels of lanthanides in uranium-bearing samples was developed. The method involves a simple co-precipitation using Fe(III) carrier in ammonium carbonate medium to remove the uranium matrix. The procedure is an effective initial pre-concentration step for the subsequent extraction chromatographic separations. The applicability of the method was...

background : the aim of the current study was to develop a marking technique as an internal marker to mark post blood meal mosquitoes by using stable phosphate isotope 32 p and determine the optimal concentration of it. methods : an isotonic physiological saline solution, containing different concentration of radioactive isotope 32 p-labeled disodium phosphate (na 2 h 32 po4) was injected into ...

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...

Mass spectrometry has served as a major tool for the discipline of proteomics to catalogue proteins in an unprecedented scale. With chemical and metabolic techniques for stable isotope labeling developed over the past decade, it is now routinely used as a method for relative quantification to provide valuable information on alteration of protein abundance in a proteome-wide scale. More recently...