300 research outputs found
Стохастикалық модельдерді қолдана отырып қаржылық болжау: қазақстанның көп тауар биржасынан анықтама
Жаһандану жағдайында Қазақстанның қаржылық болжаудың стохастикалық модельдерін қолдану арқылы Қазақстанның көп тауар биржасын зерттеуге бағытталған. Бүгінгі таңда сызықтық емес болжау модельдері, соның ішінде жасанды нейрондық желілер қаржылық болжауда кеңінен қолданылады. Осылайша сызықтық емес модельдер, сызықтық болжау модельдерінен айырмашылығы, практикалық оқыту және деректерді өңдеу үшін жоғары есептеу жүйелерімен және мәліметтерді қажет етеді. Мақаланың мақсаты стохастикалық модельдерді қолдану арқылы қаржылық болжаудың Қазақстанның тауар биржасаның жай күйін бағалау, осылайша KASE тауар биржасында стохастикалық модельдердің инвестициалық шешімдерді дұрыс қабылдау үшін қаржылық болжаудың маңызын зерттеу арқылы анықтап көрсету. Мақалада инвестисиялық оңтайлы шешімдерді қабылдау барысында минималды есептеу жүйелерін қолдану арқылы, оңтайлы шешімдер қабылдауға мүмкіндік беретін жеңілдетілген және тиімді болжау моделін құрудың жүйелік тәсілі көрсетілген. Қазақстанның тауар-шикізат биржасында сатылатын табиғи газ фьючерстері Қазақстандағы энергиягетикалық құрылымының жаппай күтілетін өзгертулерді қажет ететінін ескере отырып, зерттеуге қолайлы нысан ретінде анықталды. Мақалада оңтайлы болжау стратегиялары мен ерекшеліктерін анықтау үшін деректерді талдау мен статистикалық әдістерді қолданып, нәтижесінде дәл сызықтық болжау моделі зерттеп анықтадық. Деректерді талдау сонымен қатар нарық қатысушыларының отын-энергетика базасына қатысты оң өзгерісті анықтай отырып, зерттеу контекстін анықтауға, осы зерттеу нысанының бағалауындағы елеулі өзгерісті қолдану арқылы анықтамалар жасалды. Мақалада қаржылық болжау моделін жасау кезінде бірнеше бағыттар зерттеліп, соның ішінде апталық және жылдық заңдылықтарды анықтау, маусымдық және экзогендік айнымалыларды енгізу зерттеулері жасалды. Мақалада сыртқы тәуелділікті азайту және шум туралы деректерді бөлу әрекеттері минималды есептеу мәліметтері мен жүйелері бар модельдің өнімділігін арттырады деген қорытынды жасалады.
Түйінді сөздер: Қазақстан, KASE, қаржылық болжау, деректерді талдау, уақыт қатарын талдау, тауар нарықтары, табиғи га
Anomalous Nernst effect in the topological and magnetic material MnBi<sub>4</sub>Te<sub>7</sub>
The recently discovered magnetic topological insulators (MnBi2Te4)(Bi2Te3)n, n = 0–4, are an ideal playground to study the influence of magnetic properties on band topology, giving access to diverse quantum states in a single compound. In the low temperature-antiferromagnetic state and vanishing magnetic field, the n = 1 system is a topological insulator protected by a combination of time reversal and a translation symmetries. It has been argued that, when the antiferromagnetic phase is forced to a the fully spin polarized state by the application of an external magnetic field, this system develops Weyl cones in the conduction band, which become accessible in presence of an intrinsic electronic doping. In this work, we experimentally prove the raising of field-induced Weyl state through the detection of an intrinsic anomalous Nernst effect in a bulk single crystal of MnBi4Te7.</p
Характеристика эдильбаевской породы овец Республики Казахстан
The article analyses material from sheep domestication to the present state. Data on the world’s leading countries, where sheep breeding is most intensively developed, are given. The largest sheep populations are concentrated in China, Australia, India and Sudan. There are 995 registered local sheep breeds, of which 100 are international cross-border sheep breeds. Many species are continually becoming extinct. Therefore, the problem of preserving the unique gene pool of aboriginal breeds is acute in many countries. More than 20 breeds of sheep are bred in Kazakhstan. Over the last ten years, the number of sheep in the Republic has been between 18.0-20.0 million. The most widespread sheep breeds are Edilbay, Kazakh Arkharmerinos and Kazakh Kurdish coarse-wool sheep. Sheep of the Edilbay breed are bred in 10 regions of Kazakhstan. Edilbay breed is adapted to breeding in areas of dry steppes, semi-desert and desert regions. The article gives a brief zootechnical characteristic of Edilbay sheep and describes the epizootic situation in the Republic of Kazakhstan. Particular attention is paid to changing the breeding strategy. In further breeding and pedigree work, the aim is to create a sheep population with reduced fat content. A plan has been outlined for comprehensive studies of the sheep gene pool and phenofund, including evaluating protein, carbohydrate, fat and mineral metabolism, chemical, physiological, cytogenetic, molecular-genetic, and other research methods. Water, soil, and feed will be monitored for heavy metals and macronutrients during the experimental work.Проанализированы материалы от момента одомашнивания овец до современного состояния овцеводства. Приведены данные о ведущих странах мира, где наиболее интенсивно развивается овцеводство. Наибольшее поголовье овец сосредоточено в Китае, Австралии, Индии и Судане. Зарегистрировано 995 местных пород овец, из которых 100 относятся к международным трансграничным. Постоянно происходит исчезновение многих пород. Поэтому во многих странах остро стоит проблема сохранения уникального генофонда аборигенных пород. В Казахстане разводят более 20 пород овец. За последние 10 лет численность овец в республике находилась в пределах 18,0–20,0 млн голов. Наибольшее распространение получили такие породы овец, как эдильбаевская, казахский архаромеринос и казахская курдючная грубошерстная. Овец эдильбаевской породы в Республике Казахстан разводят в 10 областях. Эдильбаевская порода приспособлена к разведению в зонах сухих степей, полупустынных и пустынных регионов. В статье дана краткая зоотехническая характеристика эдильбаевских овец, описана эпизоотическая обстановка в Республике Казахстан. Особое внимание уделено изменению стратегии селекции. В дальнейшей селекционно-племенной работе поставлена задача создания популяции овец с уменьшенным содержанием жира. Намечен план комплексных исследований генофонда и фенофонда овец, включающий оценку белкового, углеводного, жирового и минерального обменов, использование химических, физиологических, цитогенетических, молекулярно-генетических и других методов исследований. Во время экспериментальной работы нами будет проведен мониторинг воды, почвы и кормов на содержание тяжелых металлов и макроэлементов
Features of antifungal therapy during long-lasting infectious process: a clinical case of fungal keratitis and profile of antifungal sensitivity based on assessing biofilm formation
Among infectious diseases, opportunistic mycoses hold a special place. There has been accumulating a lot of evidence regarding the clinical and epidemiological aspects of infection caused by Fusarium spp., which global incidence rate among microbial keratitis ranges from 2 to 40% depending on the geographical location of the country. Colonizing mucous membranes, fungi can exist not only in the form of plankton, but form biofilms after surface attachment, which leads to elevated resistance to multiple antifungal agents. Here we describe a clinical case of fungal keratitis due to Fusarium solani by determining profile of the antifungal sensitivity for isolated fungal strains, by taking into account their potential for biofilm formation. We used an F. solani culture isolated from the patient as well as F. solani test culture obtained from the Russian National Collection of Microorganisms. While determining the sensitivity of fungal planktonic cultures to antifungal agents from the azole group (fluconazole, voriconazole), amphotericin B and terbinafine, it was revealed that antimycotics amphotericin B and voriconazole exerted a marked antifungal activity against clinical isolate, whereas the plankton F. solani test culture was more sensitive to all groups of antifungal agents. Due to a long-lasting progressive course of the infectious process and the high biofilm-forming ability of the clinical strain F. solani, the activity of antifungal agents on biofilm cells was modeled and examined in vitro. It was shown that regarding to the fungal biofilms, value of the minimally inhibitory concentration exceeded those for planktonic cultures by 100-fold. The mechanisms of action for antifungal agents on vital parameters of fungal cell structures were analyzed by using confocal laser scanning microscopy after staining samples with propidium iodide and acridine orange for 15 min to detect changes between intact and damaged cell surface. It was found that within the biofilm fungal cells preserved viability even after exposure to high concentrations of antifungals. In addition, despite the fungicidal drug activity at substantial concentrations acting on the biofilm cell membrane, the cell nuclei remained viable. Owing to the presence ot the mechanism of resistance in mycelial fungi shown in the study, it is necessary to take into account and investigate characteristics of biofilms in terms of drug sensitivity that will allow to optimize a choice of antimicrobial therapy
A "saddle-node" bifurcation scenario for birth or destruction of a Smale-Williams solenoid
Formation or destruction of hyperbolic chaotic attractor under parameter
variation is considered with an example represented by Smale--Williams solenoid
in stroboscopic Poincar\'{e} map of two alternately excited non-autonomous van
der Pol oscillators. The transition occupies a narrow but finite parameter
interval and progresses in such way that periodic orbits constituting a
"skeleton" of the attractor undergo saddle-node bifurcation events involving
partner orbits from the attractor and from a non-attracting invariant set,
which forms together with its stable manifold a basin boundary of the
attractor.Comment: 7 pages, 7 figures, 1 tabl
Antimicrobial resistance in clinical <I>Escherichia coli</I> isolates obtained from animals
The article presents data on the phenotypic and genotypic characteristics of antimicriobial resistance in Escherichia coli clinical isolates recovered from bovine microbiota (secretions from mammary glands, cervical swabs). 127 Escherichia coli isolates were studied, i.e. 44 from mammary glands secretions and 83 from cervical swabs. Disk diffusion method was used to study antimicrobial resistance of the cultures; minimum inhibitory concentrations of antimicrobials were determined in a serial dilution method; resistance genes were detected by polymerase chain reaction. The carried out research demonstrates a wide distribution of the isolates belonging to the phenotype resistant to ansamycins (rifampicin), semi-synthetic penicillins (ampicillin and amoxicillin), tetracyclines (doxycycline). The isolates showed a lower level of resistance to macrolides (azithromycin), amphenicols (levomycetin) and aminoglycosides (tobramycin). It was found that Escherichia coli clinical isolates are sensitive to third-generation cephalosporins and fluoroquinolone antimicrobials. However, since 28.46% of cultures demonstrate intermediate resistance to third-generation cephalosporins and 49.02% of Escherichia coli DNA samples isolated from mammal gland secretions had blaDHA gene associated with resistance to this group of antimicrobials, these antimicrobials could be hardly recommended as antibiotics of choice. Absence of VIM carbapenemase-encoding gene in the DNA of the recovered isolates and a low level of phenotypic resistance (10.22% of isolates from cervical swabs) can be one of the reasons for recommending first-line carbapenems as antibiotics of choice to treat animal diseases associated with Escherichia coli, along with fluoroquinolones as reserve antimicrobials. It was found that the recovered Escherichia coli isolates are more sensitive to combination antibiotics than to mono-antibiotics
Surface states and Rashba-type spin polarization in antiferromagnetic MnBiTe
The layered van der Waals antiferromagnet MnBiTe has been predicted
to combine the band ordering of archetypical topological insulators such as
BiTe with the magnetism of Mn, making this material a viable candidate
for the realization of various magnetic topological states. We have
systematically investigated the surface electronic structure of
MnBiTe(0001) single crystals by use of spin- and angle-resolved
photoelectron spectroscopy experiments. In line with theoretical predictions,
the results reveal a surface state in the bulk band gap and they provide
evidence for the influence of exchange interaction and spin-orbit coupling on
the surface electronic structure.Comment: Revised versio
Development of competences for the application of digital technologies by medical workers
The purpose of the study – determine the features of the formation of digital competencies for healthcare workers.Цель исследования – определить особенности формирования цифровых компетенций для работников сферы здравоохранения
Stacking-Order-Dependent Excitonic Properties Reveal Interlayer Interactions in Bulk ReS<sub>2</sub>
Rhenium disulfide, a member of the transition metal dichalcogenide family of semiconducting materials, is unique among 2D van der Waals materials due to its anisotropy and, albeit weak, interlayer interactions, confining excitons within single atomic layers and leading to monolayer-like excitonic properties even in bulk crystals. While recent work has established the existence of two stacking modes in bulk, AA and AB, the influence of the different interlayer coupling on the excitonic properties has been poorly explored. Here, we use polarization-dependent optical measurements to elucidate the nature of excitons in AA and AB-stacked rhenium disulfide to obtain insight into the effect of interlayer interactions. We combine polarization-dependent Raman with low-temperature photoluminescence and reflection spectroscopy to show that, while the similar polarization dependence of both stacking orders indicates similar excitonic alignments within the crystal planes, differences in peak width, position, and degree of anisotropy reveal a different degree of interlayer coupling. DFT calculations confirm the very similar band structure of the two stacking orders while revealing a change of the spin-split states at the top of the valence band to possibly underlie their different exciton binding energies. These results suggest that the excitonic properties are largely determined by in-plane interactions, however, strongly modified by the interlayer coupling. These modifications are stronger than those in other 2D semiconductors, making ReS2 an excellent platform for investigating stacking as a tuning parameter for 2D materials. Furthermore, the optical anisotropy makes this material an interesting candidate for polarization-sensitive applications such as photodetectors and polarimetry.</p
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