Peculiarities of deep dorsal thigh muscles in moa (Aves, Dinornithiformes)
Changes in marine biodiversity through the Phanerozoic correlate much better with hyperbolic model (widely used in demography and macrosociology) than with exponential and logistic models (traditionally used in population biology and extensively applie to fossil biodiversity as well). The latter models imply that changes in diversity are guided by a *rst-order positive feedback (mo ancestors, more descendants) and/or a negative feedback arising from resource limitation. Hyperbolic model implies a second-order positive feedback. The hyperbolic pattern of the world population growth arises from a second-order positive feedback between the population size and the rate of technological growth. The hyperbolic character of biodiversity growth can be similarly accounted for by a feedback between the diversity and community structure complexity. The similarity between the curves of biodiversity and human population probably comes from the fact that both are derived from the interference of the hyperbolic trend with cyclical and stochastic dynamics.
The key regulator in the control of aggressive behavior is dopamine receptors. Association of variants in these genes with aggression has been shown in modern populations. However, these studies have not been conducted in traditional cultures. The aim of our study was to investigate population features in distributions of allele and genotype frequencies of DRD2 rs1800497, DRD4 120 bp Ins, and DRD4 exon III polymorphisms and their associations with aggressive behavior in the traditional African populations of Hadza and Datoga, which display a contrast in their culturally permitted aggression. Overall, 820 healthy unrelated Hadza and Datoga individuals were studied. Self‐rated scores of aggression were collected using Buss and Perry's Aggression Questionnaire. Polymerase chain reaction‐Restriction fragment length polymorphism (PCR‐RFLP) was used to determine the genotype of each individual. We show that the Hadza and the Datoga differed significantly in allele and genotype frequencies of all studied loci. Our association analysis detected that only ethnicity and sex of individuals significantly influenced their aggression rank, but we failed to identify any associations of DRD2 rs1800497, DRD4 120 bp Ins, or DRD4 exon III polymorphisms with aggression. Thus, our data have no strong evidence to support the involvement of polymorphisms of DRD2 and DRD4 in controlling aggressive behavior.
The paper looks into the dynamics of the population size of Russia, Ukraine and Belarus after the census of 1989. Regions and cities of these countries were the focus of the research (territorial units level NUTS-3). The analysis addresses the question to what degree the remoteness from the regional centre, i.e. the position in the core-periphery system, influences the dynamics of the population size of the territorial units of the given level. For the analytical purposes the distinction has been made between the regional centres including adjacent suburban areas and internal regional periphery comprising districts and cities. The main indicator employed was the distance between the periphery areas and regional centres. The results of the analysis show that in spite of the depopulation of all three countries and severe transformational crisis, there was a steady growth of the population size in the regional centres, while the periphery areas of the regions continued to lose the population. The mentioned differences are primarily determined by migration flows, since the fertility rates are below the replacement level in all the countries’ territories. Population tends to concentrate in the regional centres, which means urbanisation has not been completed yet. While similar patterns of population decline are observed in the periphery areas of Ukraine and Belarus, in Russia the depopulation rates are negatively influenced by the factor of remoteness of a periphery area from the regional centre. All three countries experienced rural population decline everywhere but suburban areas of the regional centres.
The hypothesis that population pressure causes increased warfare has been recently criticized on the empirical grounds. Both studies focusing on specific historical societies and analyses of cross-cultural data fail to find positive correlation between population density and incidence of warfare. In this paper we argue that such negative results do not falsify the population-warfare hypothesis. Population and warfare are dynamical variables, and if their interaction causes sustained oscillations, then we do not in general expect to find strong correlation between the two variables measured at the same time (that is, unlagged). We explore mathematically what the dynamical patterns of interaction between population and warfare (focusing on internal warfare) might be in both stateless and state societies. Next, we test the model predictions in several empirical case studies: early modern England, Han and Tang China, and the Roman Empire. Our empirical results support the population-warfare theory: we find that there is a tendency for population numbers and internal warfare intensity to oscillate with the same period but shifted in phase (with warfare peaks following population peaks). Furthermore, the rates of change of the two variables behave precisely as predicted by the theory: population rate of change is negatively affected by warfare intensity, while warfare rate of change is positively affected by population density.
В этой статье, мы рассматриваем модель влияния атмосферных инфразвуковых волн на возбуждение в магнитосфере свистовых волн. Это возбуждение происходит в результате последовательности процессов: модуляция плотности плазмы акустико-гравитационных волн, отражение свистовых волн модуляцией в ионосфере, и возбуждение свиствых волн в магнитосферном резонаторе. Изменение модуляции магнитосферного резонатора влияет на добротность плазменного магнитосферного мазера, где активной средой являются частицы радиационного пояса, и рабочим режимом - электромагнитные волны. В магнитосферном мазере могут возбуждаться собственные колебания. Эти собственные колебания часто характеризуются чередованием этапов накопления и высыпания энергичных частиц в ионосферу во время излучения свистовых волн. Численные и аналитические исследования реакции собственных колебаний на гармонические колебания коэффициента отражения свистовых волн показывают, что это может значительно изменить магнитосферные излучения ОНЧ. Наши результаты могут объяснить причины модуляции потоков энергичных электронов и интенсивности свистовых волн с временными масштабами от 10 до 150 с в дневной магнитосфере. Такие квазипериодические излучения ОНЧ часто наблюдаются в субавроральной и авроральной магнитосфере и оказывают заметное влияние на формирование явлений космической погоды.