cosmic rays in the upper troposphere (9000 meters to 15000 meters) initiate the followingnuclear chemical reaction: 1n + 14n => 14c + 1h. previous research has shown a strong effect of latitude onthe abundance of neutrons from cosmic rays. however, to date, there has been little exploration of therelationship between the latitude effect for cosmic-ray neutrons and latitudinal variations of stab...

Southern Africa, with its vast arid to semiarid areas, is considered vulnerable precipitation changes and amplifying weather extremes. However, during the last 100 ka, huge lakes existed in currently dry central Kalahari. It has been suggested that these could have due altered atmospheric circulation pattern, leading an increase or annual distribution. Past climate are recorded paleo-archives, ...

Stable carbon isotope analysis is a useful technique to obtain quantitative estimates of the relative contributions of different food sources to the nutrition of aquatic animals in ponds. This technique is being used to obtain quantitative estimates of the contribution of natural and supplemental feeds to the nutrition of tilapia in ponds in Sagana, Kenya. Results can be used to adjust feeding/...

Stable isotope signatures of primary producers display high interand intraspecific variation. This is assigned to species-specific differences in isotope fractionation and variable abiotic conditions, e.g., temperature, and nutrient and light availability. As consumers reflect the isotopic signature of their food source, such variations have direct impacts on the ecological interpretation of st...

Stable isotope labeling is a standard technique for tracing material transfer in molecular, ecological and biogeochemical studies. The main assumption in this approach is that the enrichment with a heavy isotope has no effect on the organism metabolism and growth, which is not consistent with current theoretical and empirical knowledge on kinetic isotope effects. Here, we demonstrate profound c...

it is very important to determine the stable nitrogen isotope ratio for the nitrogenous substances in aerosols and the geochemistry behavior of stable nitrate ion isotopes in aerosols in order to elucidate the chemical and physical functions of clouds. hence, aerosol field sampling was conducted in the skies offshore from malibu beach and santa barbara, california, u.s.a. on 16 and 18 july 2009...

Key-words: particulate organic matter, periphyton, nitrogen stable isotope, subtropical river The stable nitrogen isotope ratios (δ15N) of particulate organic matter (POM) and periphyton were measured at sites along the Dashahe River, a short subtropical watercourse in SE China. δ15N values of both POM and periphyton tended to increase from upstream to downstream, ranging from 1.1‰ to 7.4‰ for ...

The R-package CAMERA is a Collection of Algorithms for MEtabolite pRofile Annotation. Its primary purpose is the annotation and evaluation of LC-MS data. It includes algorithms for annotation of isotope peaks, adducts and fragments in peak lists. Additional methods cluster mass signals that originate from a single metabolite, based on rules for mass differences and peak shape comparison [1]. To...

We studied four-link food chain, periphytic microalgae and water moss (producers), trichopteran larvae (consumers I), gammarids (omnivorous--consumers II) and Siberian grayling (consumers III) at a littoral site of the Yenisei River on the basis of three years monthly sampling. Analysis of bulk carbon stable isotopes and compound specific isotope analysis of fatty acids (FA) were done. As found...