56 research outputs found

    Analysis of mating system in two Pinus cembra L. populations of the Ukrainian Carpathians

    Get PDF
    In natural pine populations, a mixed mating system is typical,characterized by the proportions of selfed and outcrossed seeds. Swiss stone pine(Pinus cembra L.) is one of the least studied European conifers in this respect. The mating system of six polymorphic allozyme loci were studied in haploid megagametophytes and diploid open-pollinated embryos in two stands located in theEast Carpathians. In the 'Gorgany' population (24 trees, 198 seeds) the mean singlelocus estimated outcrossing rate (ts) was 0.731, and the multilocus estimate (tm) was 0.773. In the 'Yayko' population the outcrossing rate was lower (27 trees, 213 seeds, ts=0.645, tm=0.700), suggesting 23-30% of seeds are self-pollinated. Correlation ofoutcrossing rate estimates among loci was less than 1, (0.300 in 'Gorgany' and 0.469 in 'Yayko') indicating biparental inbreeding occurred. Differences between tm and ts (0.042 in 'Gorgany' and 0.056 in 'Yayko') can also be influenced by consanguineous mating, indicated by the presence of spatial and genetic family structure. In small isolated populations of Pinus cembra, which are typical for the Carpathian part of the species' range, inbreeding depression may negatively affect seed quality. The high proportion of selfed seeds observed here can be expected in any seedlot of this species and should be taken into account while planning gene conservation orreforestation measures. Maternal trees in these populations showed no heterozygote deficiency at these allozyme loci, and instead showed increased proportions of heterozygotes (inbreeding coefficient FIS = -0.200 in 'Gorgany' and -0.142 in 'Yayko'). Balancing selection may explain heterozygosity levels up to and above equilibrium proportions

    Structure parameters and magnetic properties of nanosized strontium hexaferrite prepared by the sol-gel combustion method

    Get PDF
    The phase composition, structure parameters, and main magnetic characteristics of SrFe12O19 hexaferrite prepared by the sol-gel combustion method in combination with subsequent annealing at the temperature of 850°C for 6 hours are investigated. From the study of the magnetization curves in the pulsed magnetic fields the value of saturation magnetization of synthesized material was determined. The value of the magnetocrystalline anisotropy field was determined from the survey of the ferromagnetic resonance

    Assessment of genetic diversity of some Siberian and Far Eastern species of the genus Spiraea (Rosaceae) by newly developed multiplex panels of nuclear SSR loci

    Get PDF
    Taxonomic and population genetic studies of the genus Spiraea (Rosaceae) species require new informative genetic markers. We screened 37 previously published heterologous oligonucleotide primer pairs for nuclear microsatellite loci and selected eight polymorphic and most reproducible of them for PCR multiplexing which substantially increases performance of routine mass genotyping. Three multiplex sets of 3, 3 and 2 loci, respectively, were developed and tested for ability to estimate the parameters of genetic variability and  population  structure in closely related species Spiraea ussuriensis, S. f lexuosa, S. chamaedryfolia representing seven natural populations of the Russian Far East and Siberia. Allele number ranged among loci from twelve (Spth20) to three. Among 41 alleles found, 7 were unique in some species/populations. Analysis of parameters of genetic variability in Spiraea spp. showed similar values of allele number per locus and observed heterozygosity among populations and slightly greater estimates of expected hete rozygosity in the samples of S. f lexuosa (NA = 2.387; HO = 0.387 ± ± 0.052; HE = 0.540 ± 0.055) as compared to S. ussuriensis (NA = = 2.781; HO = 0.385 ± 0.079; HE = 0.453 ± 0.072) and S. chamaedryfolia (NA = 2.875; HO = 0.331 ± 0.071; HE = 0.505 ± 0.069). The observed values of genetic polymorphism parameters indicate the average level of genetic diversity of the studied species typical to previous studies in Spiraea. About 19 % of the observed variability occurred among populations (FST = 0.191) while 81 % of the total genetic variation concentrated within the populations. The loci VS11, VS12, VS2, and VS6 contributed most to the observed differentiation. Nei genetic distances  between populations ranged from 0.049 to 0.585. Genetic differentiation patterns among studied populations based on allele frequencies of nuclear microsatellite loci correspond with their geographical location. Genetic composition of some samples contradicted with their provisional species identification

    AB Initio Estimations of Transport Properties of Solid Oxide Molybdates

    Full text link
    This work is aimed at comprehensive theoretical study of Sr2MMoO6 molybdates with M = Ti, V, Cr, Mn, Fe, Co, Ni. It is shown that the experimentally observed variations of electronic conductivity in these compounds can be reasonably explained with the help of DFT calculations.Работа выполнена при поддержке Российского фонда фундаментальных исследований (РФФИ) в рамках проекта №19-79-10147

    Intraspecific structure of the Coregonus lavaretus complex in water bodies of Siberia: a case of postglacial allopatric origin of Yukagirian whitefish

    Get PDF
    The results of morphological and genetic analyses of forms/species of the Coregonus lavaretus pidschian (Gmelin, 1789) complex from the Indigirka and Kolyma river basins are presented in the context of there being recent postglacial speciation events. It has been found that the studied whitefishes belong to the sparsely rakered and low lateral-line forms and have previously been described as Coregonus lavaretus pidschian n. jucagiricus Drjagin (Berg), 1932. Based on these characters, this whitefish does not differ from most Arctic whitefish populations (in particular from Coregonus lavaretus glacialis Kirillov, 1972). Analysis of variability of the ND1 gene (mtDNA) showed that whitefishes from the Indigirka and Kolyma basins belong to a distant phylogenetic lineage, which is significantly different from all previously studied whitefish lineages from the Ob, Yenisei, Lena, Anadyr, and Amur river basins. Analysis of variability of the ITS1 fragment (nDNA) showed that all studied forms/species (from Ob River to Amur River basins), including C. l. pidschian n. jucagiricus, have a tandem arrangement of two identical nucleotide fragments and very similar nucleotide composition of the ITS1 region. Based on contemporary data, this phylogenetic lineage of the C. pidschian complex could be considered a young postglacial allopatric species.info:eu-repo/semantics/acceptedVersio

    Risk Factors of Severe Disease and Methods for Clinical Outcome Prediction in Patients with COVID-19 (Review)

    Get PDF
    Large population studies using statistical analysis and mathematical computer modeling could be an effective tool in studying COVID-19. The use of prognostic scales developed using correlation of changes in clinical and laboratory parameters and morphological data, can help in early prediction of disease progression and identification of patients with high risk of unfavorable outcome.Aim of the review. To assess the risk factors for severe course and unfavorable outcome of COVID-19 and to evaluate the existing tools for predicting the course and outcome of the novel coronavirus infection. PubMed, Medline, and Google Scholar were searched for the relevant sources. This review contains information on existing tools for assessing the prognosis and outcome of the disease, along with the brief data on the etiology, pathogenesis of the novel coronavirus infection and the known epidemiological, clinical and laboratory factors affecting its course.Conclusion. It is essential to develop predictive models tailored to specific settings and capable of continuous monitoring of the situation and making the necessary adjustments. The discovery of new and more sensitive early markers and developing marker-based predictive assessment tools could significantly impact improving the outcomes of COVID-19

    Факторы риска и методы прогнозирования клинического исхода COVID-19 (обзор)

    Get PDF
    Large population studies using statistical analysis and mathematical computer modeling could be an effective tool in studying COVID-19. The use of prognostic scales developed using correlation of changes in clinical and laboratory parameters and morphological data, can help in early prediction of disease progression and identification of patients with high risk of unfavorable outcome.Aim of the review. To assess the risk factors for severe course and unfavorable outcome of COVID-19 and to evaluate the existing tools for predicting the course and outcome of the novel coronavirus infection. PubMed, Medline, and Google Scholar were searched for the relevant sources. This review contains information on existing tools for assessing the prognosis and outcome of the disease, along with the brief data on the etiology, pathogenesis of the novel coronavirus infection and the known epidemiological, clinical and laboratory factors affecting its course.Conclusion. It is essential to develop predictive models tailored to specific settings and capable of continuous monitoring of the situation and making the necessary adjustments. The discovery of new and more sensitive early markers and developing marker-based predictive assessment tools could significantly impact improving the outcomes of COVID-19.Одним из эффективных инструментов изучения COVID-19 является исследование больших популяций пациентов и выделение факторов, влияющих на течение и прогноз, с помощью различных методов статистического анализа и математического компьютерного моделирования. Применение прогностических шкал, разработанных на основании сопоставления динамики клинических и лабораторных показателей с морфологическими данными, может помочь в своевременной оценке возможных вариантов течения заболевания и выделении больных группы высокого риска неблагоприятного исхода.Цель обзора. Оценить факторы риска тяжелого течения и неблагоприятного исхода COVID-19, существующие инструменты прогнозирования течения и исхода новой короновирусной инфекции. Поиск источников осуществляли в базах данных PubMed, Medline, Google Scholar. Данный литературный обзор наряду с краткими данными об этиологии, патогенезе COVID-19 и об известных эпидемиологических, клинических и лабораторных факторах, влияющих на ее течение, содержит информацию о существующих инструментах оценки прогноза течения и исхода заболевания.Заключение. Необходима разработка прогностических моделей, созданных под конкретные условия с возможностью постоянного мониторинга ситуации и внесения корректировок при необходимости. Обнаружение новых более чувствительных на ранних этапах заболевания маркеров и разработка на их основе инструментов оценки прогноза могло бы значительно улучшить исходы COVID-19

    ELECTRICAL TRANSPORT PROPERTIES OF MANGANESE-DOPED LANTHANUM-STRONTIUM FERRITES

    Full text link
    During the research a number of solid oxides corresponding to chemical formula LaSr2(Fe1-xMnx)3O9-δ were synthesized, their phase homogeneity was confirmed. Electrical measurements at different outer experimental conditions for compounds with x = 0.1, 0.17, 0.33 were performed

    The Demoiselle crane (Anthropoides virgo) population genetic structure in Russia

    Get PDF
    The Demoiselle crane (Anthropoides virgo Linneaus, 1758) is a widespread crane species of Eurasia distributed in the steppe and semi-desert zones from southeast Ukraine eastward to Northern China. The Demoiselle crane uses two wintering grounds in Africa and India corresponding to the European and Asian breeding parts of the range subdivided into several spatially separated breeding flocks. The first estimates of the genetic diversity and differentiation have been obtained from five of them: 1) Azov & Black Sea, 2) Caspian, 3) Volga & Ural, 4) South Siberian and 5) Eastern Asian sampled across the total breeding range in Russia using data from 10 microsatellite loci and the 1 003-bp control region of mitochondrial DNA. In total, the Demoiselle crane demonstrates high level of observed (HO = 0.638 ± 0.032) and expected (HE = 0.657 ± 0.023) hete-rozygosity and haplotype diversity (h = 0.960). Genetic dif­ferentiation among populations has shown to be weak for both the microsatellite loci (Wright’s FST = 0.052 or AMOVA estimate 0.016) and mtDNA (FST = 0.040). No evidence of significant population structuring of the Demoiselle crane has been found using the STRUCTURE analysis of multilo­cus microsatellite genotypes and the NETWORK grouping of control region haplotypes. Despite the haplotype diversity was high, the nucleotide diversity of the species was low (0.0033 ± 0.0003). Negative but non-significant Tajima’s and Fu’s tests did not suggest the recent population expansion in the Demoiselle crane evolutionary history which contrasts to other cranes of the Palearctic (the Eurasian crane Grus grus, and the Hooded crane G. monacha). These data indicate more stable conditions for the Demoiselle crane breeding groups in the steppe zone in Pleistocene as compared to boreal and subarctic breeding grounds of other crane species
    corecore