Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: dose-response

Sortuj według:

Ogranicz wyniki do:

Assessing the maximum limit of SAR-OSL dating using quartz of different grain sizes

Anechitei-Deacu V., Timar-Gabor A., Constantin D., Trandafir-Antohi O., Del Valle L., Fornós J. J., Gómez-pujol L., Wintle A. G.

Geochronometria

2018

Vol. 45, no. 1

146--159

SAR-OSL dating studies of Romanian, Serbian and Chinese loess using fine and coarse quartz have previously resulted in a series of controversial issues. We extend here the investigations using fine (4–11 μm) and different coarse quartz (>63 μm) grains extracted from aeolianites from a site on Eivissa Island (southwestern Mediterranean). Aeolianites were chosen since they contain quartz from a different geological context and have significantly lower environmental dose rates. The dose response curves of the OSL signals for fine and coarse quartz are similar to those for loess and are also represented by the sum of two saturating exponential functions. For doses up to ~200 Gy, the dose response curves of fine and coarse grains from aeolianites can be superimposed and the ages obtained for the different grain sizes are in agreement up to ~250 ka, increasing our confidence in the accuracy of the ages obtained for samples with such doses, irrespective of the magnitude of the environmental dose rate. Particularly for the fine quartz fraction, a mismatch between the SAR dose response curve and the dose response curve obtained when doses are added to the natural is reported, indicating that the application of the SAR protocol in the high dose range is problematic. This dose dependent deviation is much less pronounced for coarse grains. Thus, it seems reasonable to infer that the dose response curves for the coarse grains, although saturating earlier can be regarded as more reliable for equivalent dose calculation than those for the fine grains.

Multigenerational and Transgenerational Side-Effects of an Insecticide on Eggs of Folsomia candida (Collembola)

Szabó B., Bakonyi G.

Polish Journal of Ecology

2017

Vol. 65, nr 1

110--121

Environmental toxicants such as insecticides are able to provoke epigenetic alterations which can be inherited to future generations. The aim of the current study was to assess whether the insecticide Trebon 10F (containing the active ingredient etofenprox) causes multigenerational and/or transgenerational effects on the egg traits of the collembolan Folsomia candida. The parent generation was kept in soil treated with three concentrations of the insecticide. The hatched offspring from each treatment were divided into two groups and were treated in the same manner as their parents (multigenerational effect), or remained untreated (transgenerational effect). The parents reacted with smaller eggs to the insecticide in a concentration dependent manner. Both multigenerational and transgenerational effects were detected in the offspring generations. While neither the number of eggs nor the ratios of the egg diameters (shortest/longest diameter) changed, the egg size increased as the Trebon 10F concentration increased. This is an indication that parents living under insecticide stress transmit this information to their offspring, who react with higher quality egg production. Such alterations in egg traits may have important consequences on the F. candida population dynamic.