40 research outputs found

    Vector Theory of Gravity

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    We proposed a gravitation theory based on an analogy with electrodynamics on the basis of a vector field. For the first time, to calculate the basic gravitational effects in the framework of a vector theory of gravity, we use a Lagrangian written with gravitational radiation neglected and generalized to the case of ultra-relativistic speeds. This allows us to accurately calculate the values of all three major gravity experiments: the values of the perihelion shift of Mercury, the light deflection angle in the gravity field of the Sun and the value of radar echo delay. The calculated values coincide with the observed ones. It is shown that, in this theory, there exists a model of an expanding Universe.Comment: 9 page

    Late Pleistocene insects from the Dubrovino site at Ob River (West Siberia, Russia) and their paleoenvironmental significance

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    A blue-grey clay loam lens with plant and insect remains was found in an expo-sure of the Ob River, 2 km upper Dubrovino village in Novosibirskaya Oblast of Russia.Conventional radiocarbon dating of the Dubrovino deposit is ca 19,444±159 14C BP(23,234±338 cal yr BP) and coincides with Sartan glaciation period (MIS 2). Ninety-twoColeoptera species, dominated by fragments of Curculionidae and Carabidae are rep-resented in the Dubrovino deposit. Species of the tundra-steppe fauna are dominant,followed by meadow-dwelling taxa and coniferous forest taxa. A comparison of theDubrovino assemblage with the previously studied late Pleistocene Kalistratikha andBunkovo fossil assemblages showed that tundra-steppe landscapes with coniferousgroves and sparse meadow vegetation were typical for this area from the end of Kargininterglacial (MIS 3) through the end of the Sartan glaciation (MIS 2)

    Комплексы жесткокрылых из четвертичных отложений р. Кизиха - самые южные позднеплейстоценовые насекомые Западно-Сибирской равнины

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    Two sites with insect remains were found in an exposure on the bank of Kizikha river, in the Rubtsovskii District of the Altaiskii Krai of Russia, Kizikha-1 with radiocarbon age 13455±150 14C BP (SPb-1347), and Kizikha-2 with the age 26094±400 14C BP (SPb-1418). This period is coincides with Sartan stadial and Kargin interstadial (MIS 2 and MIS 3). This is the southernmost late Pleistocene insect bearing deposit found in West Siberia. The fragments in both sites are represented mainly by Coleoptera. Beetle fauna from the site Kizikha-1 is represented by 34 species from 9 families. The majority of fragments belong to weevils and ground beetles. 28 species from 8 families are found in Kizikha-2 site, the majority of fragments belong to Carabidae. 7 species found in the sites, Dyschiriodes rufimanus, Cymindis cf. rostowtzowi (Carabidae), Cidnopus cf. parallelus, Pristilophus punctatissimus (Elateridae), Hemitrichapion alexsandri (Brentidae), Paophilus albilaterus and Otiorhynchus sushkini (Curculionidae), are recorded in Pleistocene deposits for the first time. Sub-fossil insect assemblages of the two sites coincides with the late Pleistocene “Otiorhynchus-type” sub-fossil insect fauna from southeastern part of West-Siberian Plain (Zinovyev, 2011; Legalov et al., 2016) with characteristics as follows: dominance of steppe species, presence of halophile species, lack of forest species. Most of these species are absent in the contemporary regional fauna. The complex of eastern species and presence of endemics of Altai-Sayan Mountain system is also characteristic to the both studied sites. Specifics of the deposit assemblages in comparison with the other late Pleistocene fauna of West Siberian Plain is in high share of meadow species that could be explained by taphonomic condition of sedimentation or microclimatic conditions caused by close location to Altai mountains. Analysis of sub-fossil insect fragments showed that open landscapes with zonal steppe and sparse meadow vegetation near rivers and in depressions were typical for this area. In comparison to contemporary conditions climate was dry and cold, but Kizikha-2 (end of MIS 3) was formed in more mild climate conditions than Kizikha-1 (end of MIS 2). Results gained from Kizikha-1 and Kizikha-2 sites are complementing data on latitudinal-zonal distribution of beetles found in late Pleistocene deposits in West Siberian Plain

    Elastic principal manifolds and their practical applications

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    Principal manifolds serve as useful tool for many practical applications. These manifolds are defined as lines or surfaces passing through "the middle" of data distribution. We propose an algorithm for fast construction of grid approximations of principal manifolds with given topology. It is based on analogy of principal manifold and elastic membrane. The first advantage of this method is a form of the functional to be minimized which becomes quadratic at the step of the vertices position refinement. This makes the algorithm very effective, especially for parallel implementations. Another advantage is that the same algorithmic kernel is applied to construct principal manifolds of different dimensions and topologies. We demonstrate how flexibility of the approach allows numerous adaptive strategies like principal graph constructing, etc. The algorithm is implemented as a C++ package elmap and as a part of stand-alone data visualization tool VidaExpert, available on the web. We describe the approach and provide several examples of its application with speed performance characteristics.Comment: 26 pages, 10 figures, edited final versio

    Insects and molluscs of the Late Pleistocene at the Gornovo site (Southern Ural foreland, Russia): New data on palaeoenvironment reconstructions

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    The paper presents new data on the subfossil insects and molluscs, as well a new radiocarbon date for the Gornovo site in the Southern Fore-Urals. As a result, the stratigraphic interpretation of the sediments of the lower part of the first above floodplain terrace of the Belaya River is corrected and they are assigned to the Tabulda Horizon (MIS 3) of the Upper Pleistocene in the regional scheme of the Fore-Urals Quaternary. The malacofauna of the locality is represented by 27 species of terrestrial and freshwater molluscs. The composition of molluscs in the deposits of MIS 3 indicates the succession of deposit accumulation in the river valley from the stage of reservoirs that periodically connecting with the river to the stage of the overgrown oxbow lake. Single occurrence of mollusc shells in the loams of MIS 2 is a result of sharp climate change. New insect material includes 136 species of Coleoptera from 17 families, as well as Heteroptera and Hymenoptera representatives. 29 species of beetles (Carabidae, Histeridae, Scarabaeidae, Elateridae, Tenebrionidae, Chrysomelidae, Brentidae and Curculionidae) are recorded for the Pleistocene for the first time. The insect assemblages from Gornovo site are assigned to periglacial and humid boreal faunal types. The entomofauna of the periglacial type has no analogues in the recent fauna; it corresponds to the deposits assigned to the middle of MIS 3. This entomofauna is characteristic to the MIS 2 and MIS 3 insect assemblages from the south of West Siberian Plain. Based on entomological data, the climate of the middle of MIS 3 of the Southern Fore-Urals is reconstructed as dry and cold, extracontinental, with mean July temperature not exceeding +15 °C. Steppe landscapes likely prevailed in open areas and coniferous forests were restricted to river valleys. Beetles from deposits dated to end of MIS 3 are assigned to the fauna of the boreal humid type. These insect assemblages are significantly poorer in diversity than periglacial type assemblages and are represented mainly by near water and forest Coleoptera. Based on these species, meadow and forest landscapes were reconstructed. The reconstructed mean air temperature of July ranged from +16 to +19 °C. This suggests a trend towards more mild conditions in the region connected to the climate warming at the end of MIS 3. It is likely that humidification during this period was regional, determined by the proximity of the site to the Southern Urals Mountains. © 2021 Elsevier Ltd and INQU

    New Data on the Distribution of Southern Forests for the West Siberian Plain during the Late Pleistocene: A Paleoentomological Approach

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    Subfossil remains of insects and branchiopod crustaceans (Cladocera and Notostraca) found in three late Pleistocene deposits in the Novosibirsk region in the vicinity of the village of Suzun have been described. The calibrated radiocarbon dates for these deposits were 24,893-25,966 cal BP (Suzun-1), 20,379-20,699 cal BP (Suzun-2), and 27,693-28,126 cal BP (Nizhny Suzun), which correspond to the onset of marine isotope stage 2 (MIS 2). The insect assemblages of these deposits are mainly represented by Coleoptera, which are noteworthy for high taxonomic and ecological diversity. At least 194 beetle species from 21 families have been found altogether. Of them, 74 species were found in the Pleistocene deposits of Western Siberia for the first time. All deposits were similar in species composition of beetles; Carabidae and Curculionidae prevailed everywhere. The ecological composition was dominated by steppe and tundra-steppe species; aquatic and riparian groups were also well represented. The Cladoceran and notostracan taxa revealed in Suzun-1 and Suzun-2 are characteristic of recent steppes rather than the forest zone of Western Siberia. The studied entomocomplexes are congruent with the periglacial Otiorhynchus-type fauna that inhabited the southern part of the West Siberian Plain at the end of the Pleistocene and had no close contemporary analogues. Cold and dry conditions, as well as the prevailing open landscapes of the tundra-steppe type, were the reconstructed conditions for this fauna. At the same time, the Suzun-1 and Suzun-2 entomocomplexes had a distinctive feature, namely a high proportion of forest species associated with both coniferous and deciduous trees. According to these data, at the beginning of MIS 2 in the Upper Ob region, spruce forests with the participation of small-leaved species (birch) were present. They were probably confined to river valleys and were not widely distributed

    New Data on the Distribution of Southern Forests for the West Siberian Plain during the Late Pleistocene: A Paleoentomological Approach

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    Subfossil remains of insects and branchiopod crustaceans (Cladocera and Notostraca) found in three late Pleistocene deposits in the Novosibirsk region in the vicinity of the village of Suzun have been described. The calibrated radiocarbon dates for these deposits were 24,893–25,966 cal BP (Suzun-1), 20,379–20,699 cal BP (Suzun-2), and 27,693–28,126 cal BP (Nizhny Suzun), which correspond to the onset of marine isotope stage 2 (MIS 2). The insect assemblages of these deposits are mainly represented by Coleoptera, which are noteworthy for high taxonomic and ecological diversity. At least 194 beetle species from 21 families have been found altogether. Of them, 74 species were found in the Pleistocene deposits of Western Siberia for the first time. All deposits were similar in species composition of beetles; Carabidae and Curculionidae prevailed everywhere. The ecological composition was dominated by steppe and tundra-steppe species; aquatic and riparian groups were also well represented. The Cladoceran and notostracan taxa revealed in Suzun-1 and Suzun-2 are characteristic of recent steppes rather than the forest zone of Western Siberia. The studied entomocomplexes are congruent with the periglacial “Otiorhynchus-type” fauna that inhabited the southern part of the West Siberian Plain at the end of the Pleistocene and had no close contemporary analogues. Cold and dry conditions, as well as the prevailing open landscapes of the tundra-steppe type, were the reconstructed conditions for this fauna. At the same time, the Suzun-1 and Suzun-2 entomocomplexes had a distinctive feature, namely a high proportion of forest species associated with both coniferous and deciduous trees. According to these data, at the beginning of MIS 2 in the Upper Ob region, spruce forests with the participation of small-leaved species (birch) were present. They were probably confined to river valleys and were not widely distributed. © 2023 by the authors.Ural Branch, Russian Academy of Sciences, UB RAS: FUWU-2022-0005The studies of A.G., R.D. and A.L. were carried out under the Federal Fundamental Scientific Research Program (grant No. 1021051703269-9-1.6.12). The studies of A.A.P. were carried out under the framework of Russian state research project No. 121051100109-1. Overall, this study was carried out under a government contract with the Institute of Plant and Animal Ecology, Ural Branch of the Russian Academy of Sciences (research subject: FUWU-2022-0005)

    Regulatory feedback response mechanisms to phosphate starvation in rice

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    Phosphorus is a growth-limiting nutrient for plants. The growing scarcity of phosphate stocks threatens global food security. Phosphate-uptake regulation is so complex and incompletely known that attempts to improve phosphorus use efficiency have had extremely limited success. This study improves our understanding of the molecular mechanisms underlying phosphate uptake by investigating the transcriptional dynamics of two regulators: the Ubiquitin ligase PHO2 and the long non-coding RNA IPS1. Temporal measurements of RNA levels have been integrated into mechanistic mathematical models using advanced statistical techniques. Models based solely on current knowledge could not adequately explain the temporal expression profiles. Further modeling and bioinformatics analysis have led to the prediction of three regulatory features: the PHO2 protein mediates the degradation of its own transcriptional activator to maintain constant PHO2 mRNA levels; the binding affinity of the transcriptional activator of PHO2 is impaired by a phosphate-sensitive transcriptional repressor/inhibitor; and the extremely high levels of IPS1 and its rapid disappearance upon Pi re-supply are best explained by Pi-sensitive RNA protection. This work offers both new opportunities for plant phosphate research that will be essential for informing the development of phosphate efficient crop varieties, and a foundation for the development of models integrating phosphate with other stress responses

    Mathematical Modelling of Cell-Fate Decision in Response to Death Receptor Engagement

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    Cytokines such as TNF and FASL can trigger death or survival depending on cell lines and cellular conditions. The mechanistic details of how a cell chooses among these cell fates are still unclear. The understanding of these processes is important since they are altered in many diseases, including cancer and AIDS. Using a discrete modelling formalism, we present a mathematical model of cell fate decision recapitulating and integrating the most consistent facts extracted from the literature. This model provides a generic high-level view of the interplays between NFκB pro-survival pathway, RIP1-dependent necrosis, and the apoptosis pathway in response to death receptor-mediated signals. Wild type simulations demonstrate robust segregation of cellular responses to receptor engagement. Model simulations recapitulate documented phenotypes of protein knockdowns and enable the prediction of the effects of novel knockdowns. In silico experiments simulate the outcomes following ligand removal at different stages, and suggest experimental approaches to further validate and specialise the model for particular cell types. We also propose a reduced conceptual model implementing the logic of the decision process. This analysis gives specific predictions regarding cross-talks between the three pathways, as well as the transient role of RIP1 protein in necrosis, and confirms the phenotypes of novel perturbations. Our wild type and mutant simulations provide novel insights to restore apoptosis in defective cells. The model analysis expands our understanding of how cell fate decision is made. Moreover, our current model can be used to assess contradictory or controversial data from the literature. Ultimately, it constitutes a valuable reasoning tool to delineate novel experiments
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