Identifying mobility in populations with mixed marine/terrestrial diets : strontium isotope analysis of skeletal material from a passage grave in Resmo, Öland, Sweden

Strontium isotope analysis of skeletal material as a means to reconstruct prehistoric residential patterns has previously mainly been applied to populations with terrestrial diets. Here we present a model for populations with mixed marine/terrestrial diets, which is based on two-component mixing of strontium isotopes. Applying this model, we can estimate the original strontium isotope value of the terrestrial component of the diet. Accordingly it is possible to identify non-local individuals even if they had a mixed marine/terrestrial diet. The model is applied to tooth enamel samples representing nine individuals recovered from a passage grave in Resmo, on the island of Öland in the Baltic Sea, where at least five non-local individuals, representing at least two different geographical regions of origin, were identified. Non-local individuals were more frequent during the Bronze Age than during previous phases.

Smoking during pregnancy by duration of residence among immigrants in Sweden 1991-2012 : A study on health inequalities

This study revisits the effect of duration by residence in relation to smoking during pregnancy. It contributes to the literature by incorporating a health inequity perspective, and discusses whether immigrants tend to converge with Swedish women’s smoking. The study is based on Swedish Medical Birth Register and includes 1 1864 52 pregnancies between 1991 and 2012. Logistic regression was performed to attain crude and adjusted Odds Ratios and 95 % confidence intervals. Immigrants’ are divided by categorizing countries of origin depending on levels of Human Development (IHDI). Overall immigrant women show low levels of smoking during pregnancy when they arrive to Sweden, by duration of residence levels of smoking increase and converge with smoking patterns of Swedish women. I found that there are differences in smoking patterns depending on IHDI of the country. Immigrant women of higher categories of IHDI show higher levels of smoking although the increase of smoking is higher among immigrant women from categories of lower IHDI. However, immigrant women’s smoking during pregnancy is affected by duration of residence, and the increased smoking is associated with health inequalities related to their country of origins IHDI, and by socioeconomic inequalities in Sweden. 

Dispersal in free-living, marine, benthic nematodes : passive or active processes?

Meiofauna, and especially marine nematodes are common in sediments around the world. Despite very wide ranging distributions in many nematode species, little is presently known about their dispersal mechanisms shaping these patterns. Rafting, and perhaps ballast water transport has been suggested as viable means for nematode long-range transport. On a much smaller scale other processes have been suggested for their dispersal. They generally include some form of passive suspension into the water column and later on a passive, haphazard settling back towards the bottom. Small-scale phenomena in nematode dispersal were studied by conducting a series of studies at Askö field station, Trosa Archipelago, Baltic proper. Studied aspects were one case of macrofaunal influence on nematode dispersal rate, using an amphipod, Monoporeia affinis as disturbing agent, and three different studies on mechanisms related to settling. The experiments were conducted both in laboratory and field settings. The amphipod Monoporeia affinis did not exert any influence on the dispersal rate in the nematodes. The nematode dispersal was only an effect of time, in the aspect that the more time that past, the more nematodes dispersed from their place of origin. The settling experiments revealed that nematodes do have an active component in their settling behaviour, as they were able to exert influence on the spot where they were to settle. They were able to choose settling spot in response to the food quality of the sediment. It also became evident that contrary to common belief, nematodes are able to extend their presence in the water column far beyond the times that would be predicted considering settling velocities and hydrodynamic conditions alone.