Threshold Resonant Structure of the 232Th Neutron-Induced Fission Cross Section

The structures observed in the sub-threshold neutron-induced fission of ^{232}Th were investigated employing a recent developed model. Theoretical single-particle excitations of a phenomenological two-humped barrier are determined by solving a system of coupled differential equations for the motion along the optimal fission path. A rather good agreement with experimental data was obtained using a small number of independent parameters. It is predicted that the structure at 1.4 and 1.6 MeV is mainly dominated by spin 3/2 partial cross-section with small admixture of spin 1/2, while the structure at 1.7 MeV is given by a large partial cross section of spin 5/2.Comment: 17 pages 11 figure

Cloud chamber experiments on the origin of ice crystal complexity in cirrus clouds

This study reports on the origin of ice crystal complexity and its influence on the angular light scattering properties of cirrus clouds. Cloud simulation experiments were conducted at the AIDA (Aerosol Interactions and Dynamics in the Atmosphere) cloud chamber of the Karlsruhe Institute of Technology (KIT). A new experimental procedure was applied to grow and sublimate ice particles at defined super- and subsaturated ice conditions and for temperatures in the −40 to −60 °C range. The experiments were performed for ice clouds generated via homogeneous and heterogeneous initial nucleation. Ice crystal complexity was deduced from measurements of spatially resolved single particle light scattering patterns by the latest version of the Small Ice Detector (SID-3). It was found that a high ice crystal complexity is dominating the microphysics of the simulated clouds and the degree of this complexity is dependent on the available water vapour during the crystal growth. Indications were found that the crystal complexity is influenced by unfrozen H2SO4/H2O residuals in the case of homogeneous initial ice nucleation. Angular light scattering functions of the simulated ice clouds were measured by the two currently available airborne polar nephelometers; the Polar Nephelometer (PN) probe of LaMP and the Particle Habit Imaging and Polar Scattering (PHIPS-HALO) probe of KIT. The measured scattering functions are featureless and flat in the side- and backward scattering directions resulting in low asymmetry parameters g around 0.78. It was found that these functions have a rather low sensitivity to the crystal complexity for ice clouds that were grown under typical atmospheric conditions. These results have implications for the microphysical properties of cirrus clouds and for the radiative transfer through these clouds

Star Formation and Dynamics in the Galactic Centre

The centre of our Galaxy is one of the most studied and yet enigmatic places in the Universe. At a distance of about 8 kpc from our Sun, the Galactic centre (GC) is the ideal environment to study the extreme processes that take place in the vicinity of a supermassive black hole (SMBH). Despite the hostile environment, several tens of early-type stars populate the central parsec of our Galaxy. A fraction of them lie in a thin ring with mild eccentricity and inner radius ~0.04 pc, while the S-stars, i.e. the ~30 stars closest to the SMBH (<0.04 pc), have randomly oriented and highly eccentric orbits. The formation of such early-type stars has been a puzzle for a long time: molecular clouds should be tidally disrupted by the SMBH before they can fragment into stars. We review the main scenarios proposed to explain the formation and the dynamical evolution of the early-type stars in the GC. In particular, we discuss the most popular in situ scenarios (accretion disc fragmentation and molecular cloud disruption) and migration scenarios (star cluster inspiral and Hills mechanism). We focus on the most pressing challenges that must be faced to shed light on the process of star formation in the vicinity of a SMBH.Comment: 68 pages, 35 figures; invited review chapter, to be published in expanded form in Haardt, F., Gorini, V., Moschella, U. and Treves, A., 'Astrophysical Black Holes'. Lecture Notes in Physics. Springer 201

Смешанная инвазия кур в Котайкской области Республики Армения

The purpose of the research is study of chicken parasitic associations in small farms of Kotayk region, and analysis of the determined factors. Materials and methods. Research was conducted in 2021 to 2022 in small poultry farms of Kotayk Marz. Poultry feces samples were examined at the Laboratory of Parasitology of the Research Center of Veterinary Medicine and Veterinary Sanitary Expertise, Armenian National Agrarian University. Totally 210 fecal samples were examined. Eimeria spp. oocysts and nematode eggs were detected by means of method after Darling. The results of the research were processed by statistical methods. Results and discussion. Results of the research have shown that poultry eimeriasis had a wide prevalence in Kotayk Region (52.86%). Three species of Eimeria spp. have been detected: E. acervulina, E. tenella, and E. necatrix. E. acervulina was the most prevalence species (34.29%). The highest intensity of the infection has been registered in Nairi and Kotayk Regions of the region. The above-mentioned species of Eimeria spp. have been occurred both in mono- and poly-infection, with various combinations of the species. E. acervulina + E. tenella combination was the most common. Poultry eimeriasis occurred as a mixed-infection with ascaridiasis, heterakiasis, and capillariasis. The highest extensiveness of the poultry infection has been registered in Kotayk and Hrazdan Regions of the region (65.71% in both cases). Geographical location, as well as natural and climatic conditions of the region promote the prevalence of the mixed infection of poultry.Цель исследований – изучение паразитарных ассоциаций кур в мелких подворных хозяйствах Котайкской области и анализ обусловливающих их факторов. Материалы и методы. Исследования проводили в 2021–2022 гг. в подсобных и фермерских птицеводческих хозяйствах Котайкской области. Материалом для исследования служили образцы помета. Исследования проб помета птиц проводили в лаборатории Исследовательского центра ветеринарии и ветеринарно-санитарной экспертизы Национального аграрного университета Армении. Было изучено 210 проб помета. Обнаружение ооцист эймерий и яиц нематод в пробах помета проводили флотационным методом Дарлинга. Полученные данные подвергали статистической обработке. Результаты и обсуждение. Установлено широкое распространение эймериоза у кур в Котайкской области (52,86%). У кур обнаружены три вида эймерий: Eimeria acervulina, E. tenella, E. necatrix. Наиболее распространен вид E. acervulina (34,29%). Наиболее высокую экстенсивность инвазии регистрировали в регионах Наири и Котайк. Вышеуказанные виды эймерий встречались в виде как моно-, так и полиинвазий с различными комбинациями. Чаще всего встречалась комбинация E. acervulina + E. tenella. Эймериоз кур протекал в виде смешанной инвазии с аскаридиозом, гетеракидозом и капилляриозом. Наиболее высокую экстенсивность инвазии кур нематодами отмечали в Котайкском и Разданском регионах (по 65,71%). Географическое расположение и природно-климатические особенности области способствуют распространению у кур смешанной инвазии

Human gut microbiota community structures in urban and rural populations in Russia

The microbial community of the human gut has a crucial role in sustaining host homeostasis. High-throughput DNA sequencing has delineated the structural and functional configurations of gut metagenomes in world populations. The microbiota of the Russian population is of particular interest to researchers, because Russia encompasses a uniquely wide range of environmental conditions and ethnogeographical cohorts. Here we conduct a shotgun metagenomic analysis of gut microbiota samples from 96 healthy Russian adult subjects, which reveals novel microbial community structures. The communities from several rural regions display similarities within each region and are dominated by the bacterial taxa associated with the healthy gut. Functional analysis shows that the metabolic pathways exhibiting differential abundance in the novel types are primarily associated with the trade-off between the Bacteroidetes and Firmicutes phyla. The specific signatures of the Russian gut microbiota are likely linked to the host diet, cultural habits and socioeconomic status. © 2013 Macmillan Publishers Limited. All rights reserved

Действие акадезина на клетки рака молочной железы в условиях гипоксии

The riboside derivative acadesine (5-aminoimidazole-4-carboxamide-1-β-D-ribofuranoside) is currently being tested in clinical trials as a promising anti-tumor drug. Intracellular target of acadesine is adenosine monophosphate-activated protein kinase (АМРК), an important regulatory molecule of energy metabolism. It is expected that acadesine would be active in tumors under hypoxia conditions. In normoxia (cells incubated in 21 % oxygen), acadesine inhibited proliferation and induced cell death of breast adenocarcinoma, including the triple negative breast cancer line. When oxygen partial pressure was decreased to 1 % (experimental hypoxia), acadesine inhibited activation of reporter construct responsive to HIF-1α (hypoxia inducible factor 1 alpha) transcription factor. This effect was observed for acadesine in concentrations close to cytotoxic. Acadesine retained cytotoxicity under hypoxia and decreased the survival of the MDA-MB-231 cell line when used in combination with cisplatin. These results considerably widen acadesine’s field of application and allow to assume its efficacy in chemotherapy combination regimens for breast cancer, including the tumors with low oxygenation.Производное рибозида акадезин (5‑аминоимидазол-4‑карбоксамид-1‑β-D-рибофуранозид) проходит клинические испытания как перспективный противоопухолевый препарат. Внутриклеточная мишень акадезина аденозинмонофосфат-активируемая протеинкиназа (АМРК, adenosine monophosphate-activated protein kinase) – важный регулятор энергетического метаболизма. Правомерно предположить, что акадезин окажется активен в условиях гипоксии опухолей. В нормоксии (инкубация клеток в атмосфере с 21 % кислорода) акадезин вызывал торможение пролиферации и гибель клеток аденокарциномы молочной железы, в том числе линии трижды негативного рака. При снижении парциального давления кислорода до 1 % (экспериментальная гипоксия) акадезин ингибировал активацию промотор-репортерной конструкции, обусловленную транскрипционным фактором HIF-1α (hypoxia inducible factor 1 alpha). Этот эффект наблюдали при действии акадезина в концентрациях, сопоставимых с цитотоксическими. Акадезин сохранял цитотоксичность в условиях гипоксии и снижал обусловленную гипоксией устойчивость клеток линии MDA-MB-231 к действию цисплатина. Эти результаты расширяют область применения акадезина и позволяют предположить его эффективность в комбинированных режимах лекарственной терапии рака молочной железы, в том числе для опухолей с низкой оксигенацией

Scientific rationale for Uranus and Neptune <i>in situ</i> explorations

The ice giants Uranus and Neptune are the least understood class of planets in our solar system but the most frequently observed type of exoplanets. Presumed to have a small rocky core, a deep interior comprising ∼70% heavy elements surrounded by a more dilute outer envelope of H2 and He, Uranus and Neptune are fundamentally different from the better-explored gas giants Jupiter and Saturn. Because of the lack of dedicated exploration missions, our knowledge of the composition and atmospheric processes of these distant worlds is primarily derived from remote sensing from Earth-based observatories and space telescopes. As a result, Uranus's and Neptune's physical and atmospheric properties remain poorly constrained and their roles in the evolution of the Solar System not well understood. Exploration of an ice giant system is therefore a high-priority science objective as these systems (including the magnetosphere, satellites, rings, atmosphere, and interior) challenge our understanding of planetary formation and evolution. Here we describe the main scientific goals to be addressed by a future in situ exploration of an ice giant. An atmospheric entry probe targeting the 10-bar level, about 5 scale heights beneath the tropopause, would yield insight into two broad themes: i) the formation history of the ice giants and, in a broader extent, that of the Solar System, and ii) the processes at play in planetary atmospheres. The probe would descend under parachute to measure composition, structure, and dynamics, with data returned to Earth using a Carrier Relay Spacecraft as a relay station. In addition, possible mission concepts and partnerships are presented, and a strawman ice-giant probe payload is described. An ice-giant atmospheric probe could represent a significant ESA contribution to a future NASA ice-giant flagship mission