Intra- and inter-tooth variation in strontium isotope ratios from prehistoric seals by laser ablation multi-collector inductively coupled plasma mass spectrometry

RATIONALE

Strontium isotope ratios (⁸⁷ Sr/⁸⁶ Sr) in modern-day marine environments are considered to be homogeneous (~0.7092). However, in the Baltic Sea, the Sr ratios are controlled by mixing seawater and continental drainage from major rivers discharging into the Baltic. This pilot study explores if variations in Sr can be detected in marine mammals from archaeological sites in the Baltic Sea.

METHODS

⁸⁷ Sr/⁸⁶ Sr ratios were measured in tooth enamel from three seal species by laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS). The method enables micro-sampling of solid materials. This is the first time that the method has been applied to marine samples from archaeological collections.

RESULTS

The analyses showed inter-tooth ⁸⁷ Sr/⁸⁶ Sr variation suggesting that different ratios can be detected in different regions of the Baltic Sea. Furthermore, the intra-tooth variation suggests possible different geographic origin or seasonal movement of seals within different regions in the Baltic Sea through their lifetime.

CONCLUSIONS

The method was successfully applied to archaeological marine samples showing that: (1) the ⁸⁷ Sr/⁸⁶ Sr ratio in marine environments is not uniform, (2) ⁸⁷ Sr/⁸⁶ Sr differences might reflect differences in ecology and life history of different seal species, and (3) archaeological mobility studies based on ⁸⁷ Sr/⁸⁶ Sr ratios in humans should therefore be evaluated together with diet reconstruction.

Molecular analysis of Neanderthal DNA from the northern Caucasus

The expansion of premodern humans into western and eastern Europe approximately 40,000 years before the present led to the eventual replacement of the Neanderthals by modern humans approximately 28,000 years ago. Here we report the second mitochondrial DNA (mtDNA) analysis of a Neanderthal, and the first such analysis on clearly dated Neanderthal remains. The specimen is from one of the eastern-most Neanderthal populations, recovered from Mezmaiskaya Cave in the northern Caucasus. Radiocarbon dating estimated the specimen to be approximately 29,000 years old and therefore from one of the latest living Neanderthals. The sequence shows 3.48% divergence from the Feldhofer Neanderthal. Phylogenetic analysis places the two Neanderthals from the Caucasus and western Germany together in a clade that is distinct from modern humans, suggesting that their mtDNA types have not contributed to the modern human mtDNA pool. Comparison with modern populations provides no evidence for the multiregional hypothesis of modern human evolution.

Dietary change and stable isotopes: a model of growth and dormancy in cave bears

In order to discuss dietary change over time by the use of stable isotopes, it is necessary to sort out the underlying processes in isotopic variation. Together with the dietary signal other processes have been investigated, namely metabolic processes, collagen turnover and physical growth. However, growth and collagen turnover time have so far been neglected in dietary reconstruction based on stable isotopes. An earlier study suggested that cave bears (Ursus spelaeus) probably gave birth to cubs during dormancy. We provide an estimate of the effect on stable isotopes of growth and metabolism and discuss collagen turnover in a population of cave bears. Based on a quantitative model, we hypothesized that bear cubs lactated their mothers during their first and second winters, but were fed solid food together with lactation during their first summer. This demonstrates the need to include physical growth, metabolism and collagen turnover in dietary reconstruction. Whereas the effects of diet and metabolism are due to fractionation, growth and collagen turnover are dilution processes.

Taking the 5000 year old "Jettböle skeletons" out of the closet: a palaeo-medical examination of human remains from the Aland (Ahvenanmaa) Islands

Results of a somewhat preliminary bioanthropological study on the skeletal material from the Pitted ware site of jettböle, excavated in the parish of jomala, Aland (Ahvenanmaa) Islands, some 85-90 years ago are presented, and the causes for the disorderly distribution, including the possibility of cannibalism, are discussed.

X-ray fluorescence analysis of lead in human skeleton in vivo

The lead concentration in the skeleton of living man was measured by X-ray fluorescence analysis. Five former workers from a metal industry were studied. The mean lead concentration in their skeletons was estimated to be 62 mug/g with a standard error of +/- 5 mug/g. A comparison with the "normal" skeletal concentrations of lead in people from southern Sweden showed the skeletal concentrations of the men studied to be about three to nine times higher.

The new special names of SI units in the field of ionizing radiations

New SI units for ionizing radiations have been recommended by the internation Commission on Radiation Units and Measurements (ICRU). These are the becquerel (symbol Bq), equal to the second to the power -1, and the gray (symbol Gy), equal to the joule per kilogram. It was recommended that the roentgen be replaced as the unit of exposure by the coulomb per kilogram (C/kg), for which no new name was proposed. The ICRU recommends that the units rad, roentgen, and curie be gradually abandoned over a period of ten years and that preparatory steps to this end be taken as soon as possible by various national and international bodies in order to facilitate a smooth, safe, and efficient transition.

The new special names of SI units in the field of ionizing radiations

At its meeting in May-June 1975, the 15th Conference Generale des Poids et Mesures adopted two new special names of SI units; the becquerel, symbol Bq, equal to the second to the power minus one, s-1, for the quantity activity, and the gray, symbol Gy, equal to the joule per kilogram, J-kg-1, for absorbed dose and related quantities in the field of ionizing radiations. This action was preceded by a recommendation of the International Commission on Radiation Units and Measurements (ICRU) in 1974.

Irradiation of small structures through the intact skull

The physical conditions for producing minute disc-shaped lesions for functional radiation surgery by means of narrow beam irradiation are discussed. The intention was a treatment procedure for routine clinical use and with high physical and mechanical reproducibility. The possibilities of using high energy electrons, supervoltage roentgen radiation, gamma emitting nuclides or fast neutrons in a technique for routine clinical use were investigated. The radiation of choice taking physical properties, radiation biologic factors and practical circumstances into account was considered to be 60-Co gamma radiation. A treatment apparatus containing 179 60-Co sources within a spherical sector of 70 degrees latitude and 160 degrees longitude was constructed.