Classical Cepheids: Yet another version of the Baade-Becker-Wesselink method

We propose a new version of the Baade--Becker--Wesselink technique, which allows one to independently determine the colour excess and the intrinsic colour of a radially pulsating star, in addition to its radius, luminosity, and distance. It is considered to be a generalization of the Balona approach. The method also allows the function F(CI) = BC + 10 log (Teff) for the class of pulsating stars considered to be calibrated. We apply this technique to a number of classical Cepheids with very accurate light and radial-velocity curves and with bona fide membership in open clusters (SZ Tau, CF Cas, U Sgr, DL Cas, GY Sge), and find the results to agree well with the reddening estimates of the host open clusters. The new technique can also be applied to other pulsating variables, e.g. RR Lyrae and RV Tauri.Comment: 6 pages, 2 figures, 1 table; Submitted to Astrophysical Bulletin, 201

Morphology and Photoluminescence of HfO2Obtained by Microwave-Hydrothermal

In this letter, we report on the obtention of hafnium oxide (HfO2) nanostructures by the microwave-hydrothermal method. These nanostructures were analyzed by X-ray diffraction (XRD), field-emission gum scanning electron microscopy (FEG-SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectrometry (EDXS), ultraviolet–visible (UV–vis) spectroscopy, and photoluminescence (PL) measurements. XRD patterns confirmed that this material crystallizes in a monoclinic structure. FEG-SEM and TEM micrographs indicated that the rice-like morphologies were formed due to an increase in the effective collisions between the nanoparticles during the MH processing. The EDXS spectrum was used to verify the chemical compositional of this oxide. UV–vis spectrum revealed that this material have an indirect optical band gap. When excited with 488 nm wavelength at room temperature, the HfO2nanostructures exhibited only one broad PL band with a maximum at around 548 nm (green emission)

Estimation of permissible technological errors in the arrangement of optical elements for the hyperspectrometer according to the Offner's scheme

Рассмотрено математическое моделирование технологических погрешностей расположения оптических элементов для спектрометра по схеме Оффнера. Проведены расчёты условных допусков и анализ их влияния на изображение в плоскости регистратора. С использованием метода статистического моделирования технологической погрешности проведена оценка адекватности выбранных характеристик точности. We considered Mathematical modeling of technological errors in the arrangement of optical elements for the spectrometer according to the Offner's scheme. Calculations of conditional tolerances and analysis of their effect on the image in the plane of the recorder were carried out. We carried out the adequacy of the selected accuracy characteristics with using the method of statistical modeling of technological error

Modeling of arrangement tolerances for the optical elements in a spaceborne Offner imaging hyperspectrometer

Предложен математический аппарат, проведены исследования изображения в плоскости регистратора гиперспектрометра по схеме Оффнера, определены условные допуски на положение элементов спектрометра. Результат моделирования совместного действия погрешностей показал, что вероятность удачной сборки гиперспектрометра с соблюдением требований по качеству изображения будет не меньше 0,9.Работа выполнена при частичной поддержке грантов РФФИ № 16-29-11744, № 16-29-09528 и государственного задания ИСОИ РАН (соглашение № 007-ГЗ/43363/26)

Simulation of image formation by hyperspectral equipment taking into account the parameters of the spacecraft

Рассмотрено математическое моделирование формирования изображения гиперспектрометром по схеме Оффнера, с расположенным в плоскости регистратора электронным фотоприёмником. Для моделирования бега изображения используется модель углового движения космического аппарата с трёхосным управлением. С использованием разработанного математического аппарата проводится моделирование формирования гиперспектрального изображения для простейших геометрических примитивов. The mathematical modeling of image formation by the hyperspectrometer according to the Offner scheme with an electronic photoreceiver located in the recorder plane is considered. To simulate an image run, a model of the angular motion of a spacecraft with a three-axis control is used. Using the developed mathematical apparatus, modeling of the formation of a hyperspectral image is carried out for the simplest geometric primitives

ArdA genes from pKM101 and from B. bifidum chromosome have a different range of regulated genes

The ardA genes are present in a wide variety of conjugative plasmids and play an important role in overcoming the restriction barrier. To date, there is no information on the chromosomal ardA genes. It is still unclear whether they keep their antirestriction activity and why bacterial chromosomes contain these genes. In the present study, we confirmed the antirestriction function of the ardA gene from the Bifidobacterium bifidum chromosome. Transcriptome analysis in Escherichia coli showed that the range of regulated genes varies significantly for ardA from conjugative plasmid pKM101 and from the B. bifidum chromosome. Moreover, if the targets for both ardA genes match, they often show an opposite effect on regulated gene expression. The results obtained indicate two seemingly mutually exclusive conclusions. On the one hand, the pleiotropic effect of ardA genes was shown not only on restriction-modification system, but also on expression of a number of other genes. On the other hand, the range of affected genes varies significally for ardA genes from different sources, which indicates the specificity of ardA to inhibited targets.Author Summary. Conjugative plasmids, bacteriophages, as well as transposons, are capable to transfer various genes, including antibiotic resistance genes, among bacterial cells. However, many of those genes pose a threat to the bacterial cells, therefore bacterial cells have special restriction systems that limit such transfer.Antirestriction genes have previously been described as a part of conjugative plasmids, and bacteriophages and transposons. Those plasmids are able to overcome bacterial cell protection in the presence of antirestriction genes, which inhibit bacterial restriction systems.This work unveils the antirestriction mechanisms, which play an important role in the bacterial life cycle. Here, we clearly show that antirestriction genes, which are able to inhibit cell protection, exist not only in plasmids but also in the bacterial chromosomes themselves.Moreover, antirestrictases have not only an inhibitory function but also participate in the regulation of other bacterial genes. The regulatory function of plasmid antirestriction genes also helps them to overcome the bacterial cell protection against gene transfer, whereas the regulatory function of genomic antirestrictases has no such effect

Metagenomic analysis of microbial community of a parasitoid wasp Megaphragma amalphitanum

The vast majority of multicellular organisms coexist with bacterial symbionts that may play various roles during their life cycle. Parasitoid wasp Megaphragma amalphitanum (Hymenoptera: Trichogrammatidae) belongs to the smallest known insects whose size is comparable with some bacteria. Using 16S rRNA gene sequencing and Whole Genome Sequencing (WGS), we described microbiota diversity for this arthropod and its potential impact on their lifecycle. Metagenomic sequences were deposited to SRA database which is available at NCBI with accession number SRX2363723 and SRX2363724. We found that small body size and limited lifespan do not lead to a significant reduction of bacterial symbionts diversity. At the same time, we show here a specific feature of microbiota composition in M. amalphitanum – the absence of the Rickettsiaceae family representatives that are known to cause sex-ratio distortion in arthropods and well represented in other populations of parasitoid wasps