scholarly journals Study of model problem of structural bioinformatics

2020 ◽  
pp. 43-52
Author(s):  
Andrey Chepurnov ◽  
Nikolay Ershov
Keyword(s):  
Model Problem ◽  
Minimum Energy ◽  
Differential Evolution Algorithm ◽  
Continuous Optimization ◽  
Basic Research ◽  
Optimization Methods ◽  
Structural Bioinformatics ◽  
Automatic Testing ◽  
Graph Layout ◽  
Basic Research Grant

The paper is devoted to the study of methods for solving problems of structural bioinformatics on the example of solving a model problem of graphs layout on a plane. The paper considers an "energy" approach to solving this type of problems, based on the use of continuous optimization methods, the purpose of which is to find a configuration with a minimum energy. The paper formulates a model problem of graph layout, describes the structure of graphs to be processed, and defines an objective function that simulates the internal energy of graph layout. Several popular optimization methods are described, including a genetic algorithm and a differential evolution algorithm. Parallel variations of these two algorithms are considered. Implementation of a software system for automatic testing of a user-defined algorithm for solving model folding problems with support for parallel computing, web interface and visualization of computations is described. The work was carried out with the financial support of the Russian Foundation for Basic Research (Grant No. 20-07-01053 A).

Three modified versions of differential evolution algorithm for continuous optimization

2010 ◽  
Vol 15 (4) ◽  
pp. 803-830 ◽  
Author(s):  
Morteza Alinia Ahandani ◽  
Naser Pourqorban Shirjoposh ◽  
Reza Banimahd
Keyword(s):  
Differential Evolution ◽  
Differential Evolution Algorithm ◽  
Continuous Optimization ◽  
Evolution Algorithm

Secular geomagnetic field variations in Bulgarian lands during Classical Age and Late Antiquity – new archaeomagnetic data

2021 ◽  
Author(s):  
Maria Kostadinova-Avramova ◽  
Petar Dimitrov ◽  
Andrei Kosterov ◽  
Mary Kovacheva
Keyword(s):  
Material Culture ◽  
Late Antiquity ◽  
Basic Research ◽  
Reference Points ◽  
Archaeological Sites ◽  
Historical Sources ◽  
National Science ◽  
Basic Research Grant ◽  
National Science Fund ◽  
Research Grant

<p>Numerous historical sources and archaeological monuments attest the age of Antiquity in Bulgaria – from both the early Roman period (I – III c.) and Late Antiquity (IV – VI c.). Owing to systematic archaeological excavations, lasting more than 100 years, plenty of information has been accumulated concerning not only all aspects and manifestations of its material culture, but also their evolution and chronology.  This in turn allows for interdisciplinary fields such as archaeomagnetism to progress.</p><p>There are many archaeomagnetically studied archaeological structures from the Antiquity. The results included in the Bulgarian database form 74 reference points. However, only 20 of them are full-vector determinations because 70 % of the investigated materials are bricks. Hence, the secular variation of declination is poorly constrained within the considered period. Moreover, the reuse of bricks in the constructions occurred quite often (especially in the Late Antiquity) providing for possible errors in archaeological dating. In addition, stronger effects of magnetic anisotropy and cooling rate are usually expected for bricks than for hearths, domestic ovens, production kilns or burnt dwelling remains (there are no results from pottery in the Bulgarian dataset) and both factors are not evaluated for most of the older results. All this can explain the contradictions observed between some of the experimental results juxtaposed over the absolute time scale. In an attempt to clarify these contradictions 13 baked clay structures from eight archaeological sites were archaeomagnetically studied producing seven new directional and eight new intensity data. The samples collected possess variable magnetic properties suggesting differences in clay sources and/or firing conditions. Magnetically soft minerals prevail in seven structures but in the remaining six, abundant HCSLT phase is detected. The success rate of archaeointensity determination experiments vary from 49 to 100 %. It appears that samples containing HCSLT phase always produces good araeointensity results unlike those with the dominant presence of soft carriers.</p><p>The new reference points are compared with the present compilation of Bulgarian archaeomagnetic dataset and with the data from the neighboring countries.</p><p> </p><p>This study is supported by the grant KP-06-Russia-10 from the Bulgarian National Science Fund and Russian Foundation of the Basic Research grant 19-55-18006.</p>

Mineral assemblage within secondary crystallized melt inclusions in olivine of mantle xenoliths from the Bultfontein kimberlite pipe (Kaapvaal craton, South Africa)

2021 ◽  
Author(s):  
Alexey Tarasov ◽  
Igor Sharygin ◽  
Alexander Golovin ◽  
Anna Dymshits ◽  
Dmitriy Rezvukhin
Keyword(s):  
Melt Inclusions ◽  
Basic Research ◽  
Kimberlite Pipe ◽  
Mantle Xenoliths ◽  
Mantle Minerals ◽  
Source Regions ◽  
Basic Research Grant ◽  
Carbonate Composition ◽  
First Time ◽  
Ca Carbonate

<p>For the first time, snapshots of crystallized melts in olivine of sheared garnet peridotite xenoliths from the Bultfontein kimberlite pipe have been studied. This type of xenoliths represents the deepest mantle rocks derived from the base of lithosphere (at depths from 110 to 230 km for various ancient cratons). According to different models, such type of inclusions (secondary) in mantle minerals can be interpreted as relics of the most primitive (i.e., close-to-primary) kimberlite melt that infiltrated into sheared garnet peridotites. In general, these secondary inclusions are directly related to kimberlite magmatism that finally formed the Bultfontein diamond deposits. The primary/primitive composition of kimberlite melt is poorly constrained because kimberlites are ubiquitously contaminated by xenogenic material and altered by syn/post-emplacement hydrothermal processes. Thus, the study of these inclusions helps to significantly advance in solving numerous problems related to the kimberlite petrogenesis.</p><p>The unexposed melt inclusions were studied by using a confocal Raman spectroscopy. In total, fifteen daughter minerals within the inclusions were identified by this method. Several more phases give distinct Raman spectra, but their determination is difficult due to the lack of similar spectra in the databases. Various carbonates and carbonates with additional anions, alkali sulphates, phosphates and silicates were determined among daughter minerals in the melt inclusions: calcite CaCO<sub>3</sub>, magnesite MgCO<sub>3</sub>, dolomite CaMg(CO<sub>3</sub>)<sub>2</sub>, eitelite Na<sub>2</sub>Mg(CO<sub>3</sub>)<sub>2</sub>, nyerereite (Na,K)<sub>2</sub>Ca(CO<sub>3</sub>)<sub>2</sub>, gregoryite (Na,K,Ca)<sub>2</sub>CO<sub>3</sub>, K-Na-Ca-carbonate (K,Na)<sub>2</sub>Ca(CO<sub>3</sub>)<sub>2</sub>, northupite Na<sub>3</sub>Mg(CO<sub>3</sub>)<sub>2</sub>Cl, bradleyite Na<sub>3</sub>Mg(PO<sub>4</sub>)(CO<sub>3</sub>), burkeite Na<sub>6</sub>(CO<sub>3</sub>)(SO<sub>4</sub>)<sub>2</sub>, glauberite Na<sub>2</sub>Ca(SO<sub>4</sub>)<sub>2</sub>, thenardite Na<sub>2</sub>SO<sub>4</sub>, aphthitalite K<sub>3</sub>Na(SO<sub>4</sub>)<sub>2</sub>, apatite Ca<sub>5</sub>(PO<sub>4</sub>)<sub>3</sub>(OH,Cl,F) and tetraferriphlogopite KMg<sub>3</sub>FeSi<sub>3</sub>O<sub>10</sub>(F,Cl,OH). Note that carbonates are predominant among the daughter minerals in the melt inclusions. Moreover, there are quite a lot of alkali-rich daughter minerals within the inclusions as well. During the last decade, some research groups using different approaches proposed a model of carbonate/alkali‑carbonate composition of kimberlite melts in their source regions. This model contradicts to the generally accepted ultramafic silicate nature of parental kimberlite liquids. This study is a direct support of a new model of carbonatitic composition of kimberlite melts and also shows that alkali contents in kimberlite petrogenesis are usually underestimated.</p><p>This work was supported by the Russian Foundation for Basic Research (grant No. 20-35-70058).</p>

Model of Daytime Oxygen Emissions in the Mesopause Region and Above: New Results

2021 ◽  
Author(s):  
Valentine Yankovsky ◽  
Ekaterina Vorobeva ◽  
Rada Manuilova ◽  
Irina Mironova
Keyword(s):  
Molecular Oxygen ◽  
Excited States ◽  
Lower Thermosphere ◽  
Basic Research ◽  
Vibrationally Excited ◽  
Mesopause Region ◽  
Mesosphere And Lower Thermosphere ◽  
Basic Research Grant ◽  
The 19Th Century ◽  
Excited Oxygen

<p>Atmospheric emissions of atomic and molecular oxygen have been observed since the middle of the 19th century. In the last decades, it has been shown that emissions of excited oxygen atom O(<sup>1</sup>D) and molecular oxygen in electronically-vibrationally excited states O<sub>2</sub>(b<sup>1</sup>Σ<sup>+</sup><sub>g</sub>, v) and O<sub>2</sub>(a<sup>1</sup>Δ<sub>g</sub>, v) are related by a unified photochemical mechanism in the mesosphere and lower thermosphere (MLT). The current study is performed in the framework of the state-of-the-art model of ozone and molecular oxygen photodissociation in the daytime MLT. In particular, the study includes a detailed description of the formation mechanism for excited oxygen components in the daytime MLT and presents the comparison of widely used photochemical models. The study also demonstrates new results such as i) new suggestions about possible products of collisional reactions of electronically-vibrationally excited oxygen molecules with atomic oxygen and ii) new estimates of O<sub>2</sub>(b<sup>1</sup>Σ<sup>+</sup><sub>g</sub>, v = 0 – 10) radiative lifetimes which are necessary for solving inverse problems in the lower thermosphere. Moreover, special attention is given to the Barth’s mechanism in order to demonstrate that its contribution to O<sub>2</sub>(b<sup>1</sup>Σ<sup>+</sup><sub>g</sub>, v) and O<sub>2</sub>(a<sup>1</sup>Δ<sub>g</sub>, v) populations is neglectable in daytime conditions regardless of fitting coefficients. In addition, possible applications of the daytime oxygen emissions are presented, e.g., the altitude profiles O(<sup>3</sup>P), O<sub>3</sub> and CO<sub>2</sub> can be retrieved by solving inverse photochemical problems where emissions from electronically vibrationally excited states of O<sub>2</sub> are used as proxies. The funding of V.Y., R.M. and I.M. was partly provided by the Russian Fund for Basic Research (grant RFBR No. 20-05-00450).</p>

scholarly journals Isolation and Characterization of Lipase Inhibitory Activity from Solanum Tuberosum L (P08-040-19)

2019 ◽  
Vol 3 (Supplement_1) ◽  
Author(s):  
J Inkyu Lim ◽  
Dorsilla Anno Katimbwa
Keyword(s):  
Solanum Tuberosum L ◽  
Water Extract ◽  
Basic Research ◽  
Inhibition Activity ◽  
Funding Sources ◽  
Isolation And Characterization ◽  
Inhibitory Compound ◽  
The Stability ◽  
Basic Research Grant ◽  
Lipase Inhibition

Abstract Objectives The biochemical characteristics of the inhibitory compound to lipase isolated from potato was compared to the commercially available anti-obesity drug, Orlistat. Methods Lipase inhibitory compound was isolated from the water extract from potato by serial solvent extraction and chromatographic purifications. The lipase inhibition kinetics was assessed by double reciprocal Lineweaver-Burk plotting. the potency of lipase inhibition of the compound was compared with Orlistat using 4-MUO as a substrate. Results The lipase inhibitroy compound exhibited mixed type inhibition and high potency with an estimated IC50 of 216 ng/mL in the impure extract. The lipase inhibition activity of the compound is comparable to the commercially available anti-obesity drug, Orlistat, whose IC 50 was 0.4 ng/mL. The compound is stable at low pH (pH 2) and at boiling temperature for 1 h. Storage stability test showed that the compound is stable at least 4 weeks at RT. Conclusions Regarding the stability, solubility in water and lipase inhibition activity, the compound isolated from potato has a potential to be developed as a safe anti-obesity remedy. Funding Sources This study was funded by a basic research grant from Korean National Research Fund.

On the number of sum-free sets in a segment of positive integers

2002 ◽  
Vol 12 (4) ◽  
Author(s):  
K. G. Omelyanov ◽  
A. A. Sapozhenko
Keyword(s):  
Basic Research ◽  
Basic Research Grant ◽  
Positive Integers ◽  
Free Sets ◽  
Research Grant

AbstractA set A of integers is called sum-free if a + b ∉ A for any a, b ∈ A. For an arbitrary Ɛ > 0, let ssThis research was supported by the Russian Foundation for Basic Research, grant 01-01-00266.

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