Charge ordering and magneto-polarons in Na0.82_{0.82}CoO2_2

Using spectral ellipsometry, we have measured the dielectric function of a Na$_{0.82(2)}$CoO$_2$ crystal that exhibits bulk antiferromagnetism with T$_{N}$=19.8 K. We identify two prominent transitions as a function of temperature. The first one at 280 K involves marked changes of the electronic and the lattice response that are indicative of charge ordering in the CoO$_{2}$ layers. The second transition coincides with T$_{N}$=19.8 K and reveals a sizeable spin-charge coupling. The data are discussed in terms of charge ordering and formation of magneto-polarons due to a charge-induced spin-state transition of adjacent Co$^{3+}$ ions

Quality flags for GSP-Phot Gaia DR3 astrophysical parameters with machine learning: Effective temperatures case study

Gaia Data Release 3 (DR3) provides extensive information on the astrophysical properties of stars, such as effective temperature, surface gravity, metallicity, and luminosity, for over 470 million objects. However, as Gaia's stellar parameters in GSP-Phot module are derived through model-dependent methods and indirect measurements, it can lead to additional systematic errors in the derived parameters. In this study, we compare GSP-Phot effective temperature estimates with two high-resolution and high signal-to-noise spectroscopic catalogues: APOGEE DR17 and GALAH DR3, aiming to assess the reliability of Gaia's temperatures. We introduce an approach to distinguish good-quality Gaia DR3 effective temperatures using machine-learning methods such as XGBoost, CatBoost and LightGBM. The models create quality flags, which can help one to distinguish good-quality GSP-Phot effective temperatures. We test our models on three independent datasets, including PASTEL, a compilation of spectroscopically derived stellar parameters from different high-resolution studies. The results of the test suggest that with these models it is possible to filter effective temperatures as accurate as 250 K with ~ 90 per cent precision even in complex regions, such as the Galactic plane. Consequently, the models developed herein offer a valuable quality assessment tool for GSP-Phot effective temperatures in Gaia DR3. Consequently, the developed models offer a valuable quality assessment tool for GSP-Phot effective temperatures in Gaia DR3. The dataset with flags for all GSP-Phot effective temperature estimates, is publicly available, as are the models themselves.Comment: 13 pages, 10 figure

The PCA-seq method applied to analyze of the dynamics of COVID-19 epidemic indicators

In time series analysis using the SSA method, a univariate series is converted into the multivariate one by shifts. The resulting trajectory matrix is subjected to principal component analysis (PCA). However, the principal components can also be computed using the PCA-Seq method if segments of the original series are selected as objects. The matrix of Euclidean distances between the objects can be obtained using any method, which offers additional opportunities for time series analysis compared to the conventional SSA. In this study, the PCA-Seq method was used to analyze the dynamics of COVID-19 epidemic indicators

Studying the binder effect on the properties of briquettes of ferroalloy production waste

The paper shows the results of studies in searching for a binder for briquetting finely dispersed dust (FDD) of ferroalloy production of the Kazakhstan content. The fractional composition and shape of FDD particles were studied. Liquid glass and caustic soda were used as a binder. The research results showed the possibility of using liquid glass as a binder. Experimental briquettes have sufficiently high compressive strength and drop strength, which implies the possibility of their transportation and loading

The study of proteotomic profile of mutton with consideration to the influence of feed combinatorics

The present article is devoted to the search for markers that attest the changes in the protein profile when fattening the lambs with enriched diets, taking into account tissue specificity. The purpose of scientific research was to expand scientific knowledge about the influence of essential trace elements of organic origin in the diet of lambs on the marker-proteins of skeletal muscle tissue, of myocardium and renal cortical substance. The objects of research were the tissues of the m.L.dorsi skeletal muscle, myocardium and cortical substance of the kidneys in lambs of the Edilbaev breed. These lambs received a diet with organic trace elements (iodine, selenium, silicon). To study the effect of microelements in the diets of lambs on change in marker-proteins, we ran the studies of the skeletal muscle, myocardium and cortical substance of the kidneys of lambs, using the method of two-dimensional electrophoresis. When searching for proteins which mark the action of organic additives in the fattening diet of lambs within the tissue of the myocardium and the cortical substance of the kidneys, a number of differences were noted; no pronounced effects were observed in the skeletal muscle. Enrichment of the diet of lambs with selenium derivatives led to a change in the protein composition in the kidneys cortical substance for some isoforms of selenium-containing proteins and related enzymes of the glutathione cycle. Reaction in this process of thermal shock proteins, utilization of aflatoxins and changes in proteins of energy metabolism within mitochondria of kidney cells was also revealed. The determination of functional activity, or immunofermental analysis of glutathione peroxidase 3 count in the blood, can be a promising biomarker for controlling the level of selenium digestion and the count of selenium in blood as a more rapid and cheap method in comparison with the proteomic technologies. And for assessing the rate of digestion and fixation of iodine, it seems promising to determine it via the activity of mitochondrial superoxide dismutase [Mn]. In the myocardium, the effect of digested feed additives mainly affected the mitochondrial apparatus, which changed its functional orientation, with the activation of several other metabolic cycles. These results are prerequisites for obtaining more fundamental data on the effect of diets enriched with essential micronutrients on the molecular mechanisms that take place within the myocardial and kidney tissue of lambs. New data have been obtained on the effect of diets enriched with essential microelements on the molecular mechanisms occurring in the myocardial tissue and cortical substance of the kidneys of goats and sheep. The research results obtained by proteomics methods will be used for modeling and targeted adjustment of diets in order to obtain raw materials with the necessary technological characteristics

Shell forming mode effect on casting quality

The paper deals with the influence of shell forming modes on some parameters of castings: the surface and internal defects. The degree of roughness and stress concentration were determined on the castings obtained under production conditions. According to the result, it was found that the use of variable pressure in the formation of the shell ensures the purity of the casting and the reduction of the stress level in the casting