Manganese ores of the Lower Proterozoic Hotazel Formation (Transvaal Supergroup) associated with the banded Fe-silicites are marked by high concentrations of several rare elements (B, Ge, W, Mo, Cr, ...Ni, Zn, Cd, Pb, Ag, Bi, As, Sb, Te, Se). High boron contents in the oxide‒carbonate ores (Mn-lutites) are attributed to the chemosorptional concentration of this element on Mn-carbonates. Owing to hydrothermal transformations, a wide range of the ore-forming (mainly Fe and Mn) and rare elements (REE included) was removed from the underlying hyaloclastic basaltic andesites of the Ongeluk Formation. Manganese ores and Fe-silicites are characterized by the typical values of the cerium (Ce/Ce* 0.28–1.72) and europium (Eu/Eu* 0.57–16.31) anomalies that can suggest that primary sediments were deposited in a marginal shallow-marine basin with a prominent oxic surficial water layer and subanoxic conditions near the floor. At different stages of lithogenesis, metalliferous (Mn, Fe) sediments of the shallow-water basin were enriched in Eu (positive Eu/Eu*) and subjected to metasomatism (with the redistribution of Mn and the formation of manganese carbonates) and the consequent regional metamorphism (up to the stage of green sericite schists).
The paper deals with the acoustic emission sensor modeling by means of FEM system COSMOS M. The following types of acoustic waves in the acoustic emission sensors are investigated: the longitudinal ...wave and transversal wave. As a material is used piezoelectric ceramics. The computed displacements are compared with physical model under consideration. The results of numerical and physical simulations of the processes of acoustic wave propagation in solebar of the freight-car truck are presented. The fields of dynamic displacements and stresses were calculated for improvement of acoustic emission testing method.
The paper is dedicated to describing the methods of measuring the characteristics of suspension air springs (elastic pneumatic elements) on a test bench, as well as to the methods of evaluating their ...effect on vehicle parameters. The results of the measurement of air spring characteristics on the test bench under various conditions are presented together with the analysis of changes in their properties. A method for setting a universal force (load bearing) characteristic of the air spring, as well as a method for simulating it in the vehicle are suggested. The results of the vehicle simulation with characteristics of the air springs of different stiffness are shown, a numerical interval of the possible change in the vehicle behaviour parameters in case of change of suspension stiffness in the process of driving is specified.
The use of diamond photocathodes and electron flow multipliers in high-frequency vacuum micro- and nanoelectronics is discussed. Vacuum microtriode (microtube) and electron gun for integrated ...travelling-wave tube amplifiers are considered as the main devices of this kind.
Infectious diarrhea is one of the leading causes of fatal outcomes in young children. Differential diagnostics of such infections within the first hours of illness poses significant objective ...obstacles. Data from laboratory studies of autopsy material and pathological studies provide valuable information for understanding the spectrum of differential diagnostics and etiological structure of infectious diarrhea with fatal outcomes in young children. Materials and methods. There were analyzed 100 cases of fatal outcomes in children under the age of six years registered in Russia from November 2011 to December 2019, who was diagnosed with infectious diarrhea at different levels of the healthcare system. The data were assessed based on available medical case reports and the laboratory testing of autopsy samples performed by using nucleic acid amplification methods. Results. The diagnosis of infectious diarrhea was revised in 24 patients, based on the data of a set of intravital and post-mortem studies. In patients with unconfirmed diagnosis of acute intestinal infections, pneumonia was the most often detected — in 45.8% (11/24), sepsis — in 29.2% (7/24), meningitis/meningoencephalitis, acute surgical pathology and asphyxiation associated with vomit aspiration — in 16.7 % (4/24) cases. The causative agents of infectious diarrhea were identified in 71 of 76 patients with confirmed diagnosis of acute intestinal infections. Most prevalent were group A rotaviruses — 52.6% (40/76), group F adenoviruses — 17.1% (13/76), and noroviruses — 13.2% (10/76). Combination of pathogens was detected in 29 cases (38.2%). Prehospital lethal outcomes in patients with infectious diarrhea were observed in 17 cases (22.4%). In total, rate of neonatal deaths due to acute intestinal infections accounted for 62.2% and 2-year-old toddlers — 20.3%. 64 of 76 (84%) children had no unfavorable premorbid background. The most common pathologies associated with infectious diarrhea with developing fatal outcomes were pneumonia (including aspiration pneumonia) in 22.4% (17/76) and aspiration asphyxia in 6.6% (5/76). Hemolytic-uremic syndrome associated with diarrhea was diagnosed in 7.9% (6/76) of children. Conclusions. Within the first years of life children comprise a risk group for developing fatal outcomes during infectious diarrhea. Lack of unfavorable premorbid background should not be considered as a reliable positive prognostic criterion. Diagnostics of pneumonia should be included in the mandatory examination plan for children with severe infectious diar rhea. Based on study of clinical and autopsy material, group A rotaviruses were the lead causative agents among those resulting in infectious diarrhea with fatal outcomes in young children. Special attention should be paid to preventing vomit aspiration within the first days after disease onset.
Phys. Rev. C 105, 035201 (2022) We report on the measurement of spin density matrix elements of the
$\Lambda(1520)$ in the photoproduction reaction $\gamma p\rightarrow
\Lambda(1520)K^+$, via its ...subsequent decay to $K^{-}p$. The measurement was
performed as part of the GlueX experimental program in Hall D at Jefferson Lab
using a linearly polarized photon beam with $E_\gamma =$ 8.2-8.8 GeV. These are
the first such measurements in this photon energy range. Results are presented
in bins of momentum transfer squared, $-(t-t_\text{0})$. We compare the results
with a Reggeon exchange model and determine that natural exchange amplitudes
are dominant in $\Lambda(1520)$ photoproduction.
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