The age of rocks of the Bolshetagninskii ijolite–syenite–carbonatite massif and ultramafic dykes within the Urik-Iya Graben in the southwestern part of the Siberian Craton was studied. An isochrone ...with an age of 640 ± 11 Ma was obtained by the
147
Sm–
143
Nd method for rocks of the massif.
40
Ar/
39
Ar dating of phlogopites from rocks of the dyke series provided two plateaus with ages of 644.1 ± 8.6 and 646.1 ± 8.6 Ma. The ranges of ε
Nd
(
Т
) values corrected for 640 Ma are from +4.2 to +5.0 for rocks of the massif and from +2.9 to +4.5 for dykes and characterize a mantle source close that of OIB. Ijolite and carbonatite of the massif have ε
Nd
(
Т
) values from +4.6 to +5.0 and ε
Sr
(
Т
) values from –7 to –10, which indicates a common silicate–carbonate parental melt for them. Variations in the initial (
87
Sr/
86
Sr)
t
ratio from 0.7025 to 0.7059 in dykes most likely reflect both the heterogeneity in the isotopic composition of the mantle source and the different degrees of contamination of mantle melts by the material of the upper continental crust.
The results of study of primary melt inclusions in сhromium spinel of kimberlites of the middle Paleozoic Zapolyarnaya pipe (Upper Muna field, Siberian Craton) are presented. The inclusions are ...composed of an aggregate of daughter minerals: calcite, dolomite, nyerereite Na
2
Ca(CO
3
)
2
, gregoryite (Na,K)
2
CO
3
, northupite Na
3
Mg(CO
3
)
2
Cl, bradleyite Na
3
Mg(PO
4
)(CO
3
), apatite, chlorides (sylvite and/or halite), phlogopite, olivine, magnetite, and djerfisherite K
6
(Fe,Cu,Ni)
25
S
26
Cl. Carbonates are dominant over silicates. The assemblage of daughter minerals in the inclusions indicates a Si-depleted and alkali- (both Na and K) and CO
2
-rich, probably, alkali-carbonatitic parental kimberlite melt for the Zapolyarnaya pipe.
The paper presents data on noble-metal mineralization in carbon-bearing rocks of the Sarma Group in the southern flank of the Baikal inlier of the Siberian craton basement. The phase composition of ...the accessory ore minerals (pyrite, arsenopyrite, microinclusions of native Ni, Sn, Zn, Cu, Fe–Ni and Ni–Fe–Ti composite compounds, Cu and Pb sulfides, rutile, monazite, zircon, and barite) were determined by X-ray microanalysis. Gold, silver, and all elements of the platinum group were determined by scintillation arc atomic emission spectrometry in rock samples from the Ilikta and Hulurtui formations. These elements occur as particles of native noble metals, their intermetallic compounds, sulfides, arsenides, selenides, and sulfosalts. Noble-metal mineralization in the Hulurtui and Ilikta formations of the Sarma Group is proved to be genetically related to tectono-metasomatic processes that affected the primary metasedimentary rocks.
Intraoperative recording of cortico-cortical evoked potentials (CCEPs) enables studying effective connections between various functional areas of the cerebral cortex. The fundamental possibility of ...postoperative speech dysfunction prediction in neurosurgery based on CCEP signal variations could serve as a basis to develop the criteria for the physiological permissibility of intracerebral tumors removal for maximum preservation of the patients' quality of life. The aim of the study was to test the possibility of predicting postoperative speech disorders in patients with glial brain tumors by using the CCEP data recorded intraoperatively before the stage of tumor resection. Materials and MethodsCCEP data were reported for 26 patients. To predict the deterioration of speech functions in the postoperative period, we used four options for presenting CCEP data and several machine learning models: a random forest of decision trees, logistic regression, and support vector machine method with different types of kernels: linear, radial, and polynomial. Twenty variants of models were trained: each in 300 experiments with resampling. A total of 6000 tests were performed in the study. ResultsThe prediction quality metrics for each model trained in 300 tests with resampling were averaged to eliminate the influence of "successful" and "unsuccessful" data grouping. The best result with F1-score = 0.638 was obtained by the support vector machine with a polynomial kernel. In most tests, a high sensitivity score was observed, and in the best model, it reached a value of 0.993; the specificity of the best model was 0.370. ConclusionThis pilot study demonstrated the possibility of predicting speech dysfunctions based on CCEP data taken before the main stage of glial tumors resection; the data were processed using traditional machine learning methods. The best model with high sensitivity turned out to be insufficiently specific. Further studies will be aimed at assessing the changes in CCEP during the operation and their relationship with the development of postoperative speech deficit.
The method of integral equations is suggested for calculating irregular twisted guided structures. The method is based on the Lorentz integral relationship and makes it possible to solve internal ...diffraction problems for waveguides, whose screening surface is described by analytical functions.
This paper reports on diagnostic and structural studies that were first carried out for carbonaceous material of quartz–muscovite dynamoschists from the schistosity zone in biotite migmatites, ...pegmatites, and diabases of the southern part of the Baikal ledge of the Siberian craton. The carbonaceous material is represented by phanerocrystalline and microcrystalline graphite with residual hydrocarbon radicals. Native Ni, Sn, zincous Cu, Fe–Ni compounds, sulfides of Cu, rutile, monazite, and zircon were revealed in the intergrowths with carbonaceous material. The carbon isotopic composition ranges from –29.19‰ to –31.58‰, except for carbonaceous material from the schistocity diabase, where δ
13
C = –24.93‰.
40
Ar–
39
Ar dating of muscovite gave an age of 1947 ± 7.8 Ma pointing to the relation between dynamic metamorphism with accretion of the Akitkan fold system and the ancient complexes of the craton. It was concluded that the deposition of native carbon and metals was caused by migration of essentially hydrocarbonate fluid in the formations of the upper crust (Fig. 4, Table 1).
Abstract A set of 13 dinucleotide STR loci (G1A, G10B, G1D, G10L, MU05, MU09, MU10, MU15, MU23, MU26, MU50, MU51, MU59) were selected as candidate markers for a DNA forensic profiling system for ...Northern European brown bear ( Ursus arctos ). We present results from validation of the markers with respect to their sensitivity, species specificity and performance (precision, heterozygote balance and stutter ratios). All STRs were amplified with 0.6 ng template input, and there were no false bear genotypes in the cross-species amplification tests. The validation experiments showed that stutter ratios and heterozygote balance was more pronounced than in the tetranucleotide loci used in human forensics. The elevated ratios of stutter and heterozygote balance at the loci validated indicate that these dinucleotide STRs are not well suited for interpretation of individual genotypes in mixtures. Based on the results from the experimental validations we discuss the challenges related to genotyping dinucleotide STRs in single source samples. Sequence studies of common alleles showed that, in general, the size variation of alleles corresponded with the variation in number of repeats. The samples characterized by sequence analysis may serve as standard DNA samples for inter laboratory calibration. A total of 479 individuals from eight Northern European brown bear populations were analyzed in the 13 candidate STRs. Locus MU26 was excluded as a putative forensic marker after revealing large deviations from expected heterozygosity likely to be caused by null-alleles at this locus. The remaining STRs did not reveal significant deviations from Hardy–Weinberg equilibrium expectations except for loci G10B and MU10 that showed significant deviations in one population each, respectively. There were 9 pairwise locus comparisons that showed significant deviation from linkage equilibrium in one or two out of the eight populations. Substantial genetic differentiation was detected in some of the pairwise population comparisons and the average estimate of population substructure ( FST ) was 0.09. The average estimate of inbreeding ( FIS ) was 0.005. Accounting for population substructure and inbreeding the total average probability of identity in each of the eight populations was lower than 1.1 × 10−9 and the total average probability of sibling identity was lower than 1.3 × 10−4 . The magnitude of these measurements indicates that if applying these twelve STRs in a DNA profiling system this would provide individual specific evidence.
A method of solving problems of calculating transfer characteristics of smooth junctions between two out-of-line screened waveguides having different cross-sections is suggested. The method results ...in the collocation algebraization of integral equations based on the Lorentz lemma.
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