Strategies for Sharing Limited Resources among Children and Adolescents in Three Traditional Societies of East Africa: Sociocultural and Genetic Factors.

Egalitarianism, pursuit for equality, and altruism are the most important evolutionarily stable strategies in the human society. This study presents data on the results of economic games for sharing with a potential friend or unfamiliar peer in three ethnic groups of East Africa (Hadza, Iraqw, and Meru). The total sample was 583 children and adolescents; mean age, 13.5 ± 3.1 years. In addition, DNA analysis was carried out and the OXTR gene rs53576 single nucleotide polymorphism was genotyped for 162 Meru individuals. The pronounced individual variability in making decisions on sharing with a potential partner was established. Children and adolescents behaved altruistically towards friends significantly more frequently as compared with strangers. Carriers of the OXTR rs53576 GG variant displayed altruism significantly more frequently both to friends (U = 3376.500, p = 0.047; OR = 3.075, p = 0.032) and to strangers (U = 3478.000, p = 0.025; OR = 3.133, p = 0.007). Significant intergroup differences in egalitarianism, egoism, and altruism were also demonstrated. Data obtained suggest a positive group selection towards altruists.

The association between 2D:4D ratio and aggression in children and adolescents: Cross-cultural and gender differences.

BACKGROUND: Two recent meta-analyses have suggested the association between digit ratio (2D:4D) and aggression is weak. This conclusion has been criticised because the meta-analyses conflate forms of aggression that show strong sex differences with those that do not, and most studies have considered post-pubertal participants. AIMS: We test the influence of 2D:4D and ethnicity in the expression of aggression in children and adolescents in four ethnic groups of European and African origin. STUDY DESIGN: Buss and Perry aggression questionnaire. Direct measurement of the 2nd and 4th digits. SUBJECTS: 1296 children and adolescents from Tanzania and Russia from 4 ethnic groups - Datoga, Meru, Russians, Tatars. RESULTS: There were ethnic and gender differences in ratings on aggression with boys consistently reporting more physical aggression. In all four samples right 2D:4D was significantly lower in boys, compared to girls. With regard to our total sample of boys, the right 2D:4D was significantly and negatively associated with self-ratings on physical aggression, but no association was found for left 2D:4D. No associations between 2D:4D and physical aggression were found for girls. Hostility was negatively correlated with 2D:4D for boys, and anger was positively correlated with 2D:4D in girls. CONCLUSION: Sex differences were strongest for right 2D:4D (boysgirls). Right 2D:4D was negatively related to physical aggression in boys only, suggesting possible relationship to prenatal androgenization.

Unconsidered sporadic sources of carbon dioxide emission from soils in taiga forests.

Long-term monitoring in the Russian taiga zone has shown that all known extreme destructive effects resulting in the weakening and death of tree stands (windfalls, pest attacks, drought events, etc.) can be sporadic, but significant sources of CO2 soil emission. Among them are (i) a recently found effect of the multiyear CO2 emission from soil at the bottom of deadwood of spruce trees that died due to climate warming and subsequent pest outbreaks, (ii) increased soil CO2 emissions due to to the fall of tree trunks during massive windfalls, and (iii) pulse CO2 emission as a result of the so-called Birch effect after drought events in the taiga zone. According to the modeling, while depending on the spatial and temporal scales of their manifestation, the impact of these sporadic effects on the regional and global soil respiration fluxes could be significant and should be taken into consideration. This is due to continuing Climate Change, and further increase of local, regional and Global human impacts on the atmospheric greenhouse gases balance, and land use, as well.

[The influence of local anthropogenic factors on soil emission of biogenic greenhouse gases in cryogenic ecosystems].

For the first time were the results of studies on influence of main kinds of local anthropogenic factors on soil emission of biogenic greenhouse gases (CO2, CH4, and N2O) in permafrost ecosystems of Arctic and North-Boreal zones of the Russian Federation, and also of the Spitsbergen Archipelag summarized. Different types of land use can, depending on their manner, lead to significant enhancing or suppression of soil CO2 emission. On average, anthropogenic factors (AFs), acting in concert, favor the enhancement of local CO2 soil emission, promoting, at the same time, an increase in its dispersion. AFs directly influence the microbial-root respiration in soil, modify the soil itself, and indirectly affect important natural respiration regulators, phytomass reserves in particular, which makes them primary factors with relation to respiration pattern. AFs influence also the emission of other biogenic greenhouse gases (CH4 and N2O), though this influence can be exercised in different ways. Methane emission is mediated by degree of the territory drainage. However, in all studied cases, AFs have led to source reduction or sink intensification of this gas from the atmosphere. Unlike methane emission, N2O emission increased under the influence of AFs considered. As for the whole complex of AFs that impacts the carbon balance and fluxes of CO2 in cryogenic ecosystems, its role is expressed through the enhancement of soil respiration at the beginning of the cold season, when AFs are capable of soil emission increasing, at the level of meso-landscape, almost by 50%.

[Comparative Analysis of Polymorphisms of the Serotonin Receptor Genes HTR1A, HTR2A, and HTR1B in Hadza and Datoga Males].

The distribution of the allele and genotype frequencies of polymorphic loci of serotonin receptor genes (HTR1A, rs6295; HTR2A, rs6311; HTR1B, rs6296) in Hadza (n = 197) and Datoga males (n = 230) living in Tanzania was determined. It was shown that the populations significantly differ by the frequencies of alleles and genotypes of the rs6295 locus of the HTR1A gene. The G-allele (0.779) and the genotype G/G (0.590), which are markers of increased risk of suicidal and impulsive behavior, respectively, are revealed in Hadza with high frequency. It was found that the frequency of homozygous G/G of the rs6296 locus of the HTR1B gene, which is a marker of increased risk of outward directed aggression, is higher in Datoga (0.563) than in Hadza (0.457). The allele and genotype frequencies of the rs6311 locus of the HTR2A gene do not differ among the Hadza and Datoga males. The data on the distribution of allele and genotype frequencies of the HTR1A, HTR2A, and HTR1B genes can be used to determine the associations of the identified markers with various forms of human aggressive behavior.

[A field study of tundra plant litter decomposition rate via mass loss and carbon dioxide emission: the role of biotic and abiotic controls, biotope, season of year, and spatial-temporal scale].

Although many recently published original papers and reviews deal with plant matter decomposition rates and their controls, we are still very short in understanding of these processes in boreal and high latiude plant communities, especially in permafrost areas of our planet. First and foremost, this is holds true for winter period. Here, we present the results of 2-year field observations in south taiga and south shrub tundra ecosystems in European Russia. We pioneered in simultaneous application of two independent methods: classic mass loss estimation by litter-bag technique, and direct measurement of CO2 emission (respiration) of the same litter bags with different types of dead plant matter. Such an approach let us to reconstruct intra-seasonal dynamics of decomposition rates of the main tundra litter fractions with high temporal resolution, to estimate the partial role of different seasons and defragmentation in the process of plant matter decomposition, and to determine its factors under different temporal scale.

[Interannual changes in PAR and soil moisture during the warm season may be more important for directing of annual carbon balance in tundra than temperature fluctuations].

A lot of studies on the impact of global climate changes on natural communities deal with cryogenic ecosystems, tundra in particular, since they are delimited by low air temperature and permafrost, thus being extremely sensitive to long-term climate fluctuations. Continuous warming in Northern Hemisphere is unmasking all the more details concerning complex system of direct relationships, feedbacks, and interactions of carbon balance factors as the main response function. While the set of such factors may be viewed as more or less complete, their relative contribution to C-balance, as is becoming clear with accumulating results of field observations, directly depends on temporal scale of observations and is not constant. As the results of field observations and modeling of tundra ecosystems show, any one of significant factors can become the leading one within the boundaries determined by the given scale of observations. Even the least significant factor can become the determining one for direction of carbon annual net flux in an ecosystem, if contributions of more significant factors canceled each other during the period of observations. In the most general situation, the greater is the variation of a significant factor during the period of observations, the larger is its partial contribution. The complete set of independent variables of C-balance is not limited by abiotic factors but should include such an important factor as a stock of plants living top mass, which can be treated as not only the natural product of C-balance but also as its independent parameter.

[Geoinformational model of the carbon reserve of the Russian tundra zone]. / Geoinformatsionnaia model' biudzheta ugleroda tundrovoi zony Rossii.

We present a summary of our own gas measurement data on biogenic fluxes of CO2 in various ecosystems of the Russian tundra zone, using seasonal and geographical extrapolations based on mathematical simulation modeling. The model follows construction principles of geoinformational systems and consists of (1) a computer map of tundra landscape boundaries; (2) a meterological database; (3) a model of changes of the phytomass; and (4) the actual model of carbon fluxes. The model, which uses a 10-day step, allows estimates of regional and landscape-associated macroscopic carbon fluxes and predicts the response of the tundras to climatic changes. The data obtained are in good agreement with independently obtained estimates of the major characteristics of tundra carbon balance.