23 research outputs found
Photoionization of ultracold and Bose-Einstein condensed Rb atoms
Photoionization of a cold atomic sample offers intriguing possibilities to
observe collective effects at extremely low temperatures. Irradiation of a
rubidium condensate and of cold rubidium atoms within a magneto-optical trap
with laser pulses ionizing through 1-photon and 2-photon absorption processes
has been performed. Losses and modifications in the density profile of the
remaining trapped cold cloud or the remaining condensate sample have been
examined as function of the ionizing laser parameters. Ionization
cross-sections were measured for atoms in a MOT, while in magnetic traps losses
larger than those expected for ionization process were measured.Comment: 9 pages, 7 figure
Dietary Heterogeneity among Western Industrialized Countries Reflected in the Stable Isotope Ratios of Human Hair
Although the globalization of food production is often assumed to result in a homogenization of consumption patterns with a convergence towards a Western style diet, the resources used to make global food products may still be locally produced (glocalization). Stable isotope ratios of human hair can quantify the extent to which residents of industrialized nations have converged on a standardized diet or whether there is persistent heterogeneity and glocalization among countries as a result of different dietary patterns and the use of local food products. Here we report isotopic differences among carbon, nitrogen and sulfur isotope ratios of human hair collected in thirteen Western European countries and in the USA. European hair samples had significantly lower δ13C values (−22.7 to −18.3‰), and significantly higher δ15N (7.8 to 10.3‰) and δ34S (4.8 to 8.3‰) values than samples from the USA (δ13C: −21.9 to −15.0‰, δ15N: 6.7 to 9.9‰, δ34S: −1.2 to 9.9‰). Within Europe, we detected differences in hair δ13C and δ34S values among countries and covariation of isotope ratios with latitude and longitude. This geographic structuring of isotopic data suggests heterogeneity in the food resources used by citizens of industrialized nations and supports the presence of different dietary patterns within Western Europe despite globalization trends. Here we showed the potential of stable isotope analysis as a population-wide tool for dietary screening, particularly as a complement of dietary surveys, that can provide additional information on assimilated macronutrients and independent verification of data obtained by those self-reporting instruments