240 research outputs found

    Genetic diversity of the Aporrectodea caliginosa complex in Russia

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    Earthworms of the Aporrectodea caliginosa species complex are abundant in many anthropogenic and natural habitats and often predominate in earthworm communities. In Russia, there are two subspecies of the complex, A. c. caliginosa and A. c. trapezoides; Aporrectodea longa was also recently mentioned as a putative member of the complex. In this study, we made an attempt to review available data on the species complex studied based on our collection from Russia, Belarus, and Kazakhstan. The subspecies A. c. caliginosa is represented in Russia by two genetic lineages, 2 and 3, the former being the prevalent (about 73 % of the total sample). Additionally, these lineages have different distributions: while lineage 2 was found in almost all locations studied, lineage 3 was detected only in a few samples from the periphery of the region studied. The genetic diversity of lineage 2 significantly exceeded that of lineage 3, and its estimated divergence time was almost three times as high. A subset of individuals with pigmentation characteristic of A. c. caliginosa contained cox1 haplotypes of A. c. trapezoides; analysis of nuclear gene sequences confirmed this diagnosis. Thus, pigmentation intensity in this subspecies was demonstrated to vary to a significant degree. In addition, we analyzed two A. longa individuals from West Siberia and the Urals; their cox1 sequences were identical to those from the lineage 1 of this species from the north of Western Europe. These are the first reports of A. c. trapezoides and A. longa from West Siberia. On the whole, both genetic diversity and abundance was shown to decrease in the following series: A. c. caliginosa lineage 2 – A. c. caliginosa lineage 3 – A. c. trapezoides and A. longa

    Vibro-Injection Pile Installation in Sand: Part I—Interpretation as Multi-material Flow

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    The installation of vibro-injection piles into saturated sand has a significant impact on the surrounding soil and neighboring buildings. It is generally characterized by a multi-material flow with large material deformations, non-stationary and new material interfaces, and by the interaction of the grain skeleton and the pore water. Part 1 in this series of papers is concerned with the mathematical and physical modeling of the multi-material flow associated with vibro-injection pile installation. This model is the backbone of a new multi-material arbitrary Lagrangian-Eulerian (MMALE) numerical method presented in Part 2.DFG, 76838227, Numerische Modellierung der Herstellung von Rüttelinjektionspfähle

    Высокотеплопроводная карбидокремниевая керамика для крупногабаритной космической оптики

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    The paper describes the important aspects of the developed technology for manufacturing silicon-carbide substrates for optical mirrors intended for future use in space applications. It is shown that the material with the best combination of thermophysical and mechanical properties (Maksutov’s criterion) among the known analogs used for making astronomical mirrors is obtained. The characteristics of a mirror made of a lightweight mirror substrate with a diameter of 205 mm are described, compared with the parameters of most known mirrors made of silicon carbide for various space missions and as proto types. It is shown that the produced substrate is characterized by a rather low specific gravity – 16.5 kg/m2, which is comparable with the indicators of the best world analogues.Описаны важные аспекты разработанной технологии изготовления карбидокремниевых подложек для оптических зеркал, предназначенных для перспективного использования в космических приложениях. Показано, что получен материал с лучшим сочетанием теплофизических и механических свойств (критерий Максутова) среди известных аналогов, применяемых при создании астрономических зеркал. Описаны характеристики изготовленной из него облегченной подложки зеркала диаметром 205 мм, проведено сравнение с параметрами большинства известных зеркал, изготовленных из карбида кремния для различных космических миссий и в качестве опытных образцов. Показано, что изготовленная подложка характеризуется низкой удельной массой – 16,5 кг/м2, что сопоставимо с показателями лучших мировых аналогов

    Global data on earthworm abundance, biomass, diversity and corresponding environmental properties

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    14 p.Earthworms are an important soil taxon as ecosystem engineers, providing a variety of crucial ecosystem functions and services. Little is known about their diversity and distribution at large spatial scales, despite the availability of considerable amounts of local-scale data. Earthworm diversity data, obtained from the primary literature or provided directly by authors, were collated with information on site locations, including coordinates, habitat cover, and soil properties. Datasets were required, at a minimum, to include abundance or biomass of earthworms at a site. Where possible, site-level species lists were included, as well as the abundance and biomass of individual species and ecological groups. This global dataset contains 10,840 sites, with 184 species, from 60 countries and all continents except Antarctica. The data were obtained from 182 published articles, published between 1973 and 2017, and 17 unpublished datasets. Amalgamating data into a single global database will assist researchers in investigating and answering a wide variety of pressing questions, for example, jointly assessing aboveground and belowground biodiversity distributions and drivers of biodiversity change
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