Presolar diamonds in Krymka: C, N and Xe isotope data from grain-size separates and comparison with other meteorites

Comparison of carbon isotope variations in grain size fractions of presolar diamonds separated from three meteorites (Efremovka, Boriskino and Krymka) suggest that diamond from various parts of solar nebular have had diffrent C isotope signature

On the variations of the elemental composition of the P3 component in presolar diamonds

Analysis of noble gas element variations in the P3 component of presolar diamonds indicates that a special mechanism of element fractionation is required to explain the variations

Is Xe-HL a real component?

Analysis of noble gases in the grain-size fractions of Boriskino meteorite indicate that Xe-HL is a real component implanted into diamonds after mixing of isotopically anomalous and normal components

Separation of Q from carbon in CR meteorites during stepped combustion

Introduction: The nature of the planetary noble gas carrier (Q) in meteorites remains uncertain. It is known that it is likely to be carbonaceous, but represents only a small fraction of the total macromolecular material. Q is oxidisible with nitric and other oxidizing acids. It seems to be partly destroyed with pyridine and may have an organic structure. Previously, we have shown that during parent body thermal metamorphism Q is less affected than the majority of other carbonaceous materials. If organic matter is graphitized, as has happened in the enstatite chondrite parent bodies, Q remains unaffected. In the present study we have found that Q is also separable from the majority of carbon in type 2 and 3 CR chondrites during stepped combustion. It is possible that this is because Q has become encased within the matrix, in contrast to other carbon phases, during parent body metamorphism

Initial State Fluctuations and Complete Destruction of the Projectile Nucleus in Interactions of Asymmetric Nuclei at High Energies

A study of characteristics of the events of complete destruction of the projectile nucleus in the interactions between asymmetric nuclei for different initial states of the collision, is performed. In the interactions of the sulfur nuclei with heavy emulsion nuclei at energy 200 AGeV, anomalous high number of events the complete destruction of the projectile nuclei, is observed. The high probability of such events depends on the energy of interaction (it is not detected in the interactions of the sulfur nuclei with emulsion nuclei at energy of 3.7 AGeV), on the degree of asymmetry of the interacting nuclei (it is not detected in interactions of the sulfur nuclei with light emulsion nuclei) and on initial state of interaction (it is not detected in peripheral collisions). These events are characterized by high multiplicity of secondary particles and narrow angular distribution at large angles (they form narrow peak in the region of small values of average pseudorapidity)

Зараженность 7 сортов картофеля вирусами в полевых условиях Приморского края РФ

Scientific relevance. Plant viruses cause a significant economic loss to potato production, especially if plants are infected at early growth stages and infections are mixed. Viral diseases reduce both yield and quality of harvested crops. Detection and identification of plant viruses are key important to prevent their spreading and to achieve potential yield predetermined by characteristics of varieties.Research methods. Seven potato varieties, bred in Russia and overseas, were used in the field experiment: Smak, Avgustin, Yantar, Laperla, Labella, Red Lady, Sante, Belmonda. Viral infection rate was measured by the percent of plants with symptoms to the total number of plants. In addition to infection frequency, a disease rate was described after visual estimation. Total RNA was isolated from the collected leaves according to Bekesiova I. et al. 1999 [13]. Qualitative and quantitative estimation of plant viruses in the samples were conducted by single-step real-time RT-PCR with fluorescent detection with the Applied Biosystems QuantStudio 5 and commercial kits “Potato Virus X, Y, M, L, S, A, PSTVd-RT” (Syntol Company) according to the official protocol of the kits.Results. As a result of our research, symptoms of mixed viral infection were described for potato varieties depending on concentrations and proportions of these viruses in a plant. Mixed viral infection in the potato field in Primorsky Krai comprised PVY, PVX, PVA, PVS, PVM, also PLRV and PSTVd. Актуальность. Фитовирусы приводят к большим экономическим потерям в производстве картофеля, особенно если растения инфицируются на ранних стадиях или при смешанных инфекциях. Вирусные инфекции не только снижают урожай, но и ухудшают его качество. Обнаружение и идентификация вирусов растений имеет первостепенное значение для предотвращения их распространения и обеспечения урожайности, заложенной характеристиками сортов.Методика исследования. В полевом эксперименте, заложенном стационарно, использовалось 7 сортов картофеля российской и зарубежной селекции: Смак, Августин, Янтарь, Laperla, Labella, Red Lady, Sante, Belmonda. Проявление фитовирусной инфекции оценивали по наличию растений с симптомами от общего числа в процентах. Кроме показателя частоты заражения, при визуальной оценке описывали степень развития болезни. Тотальную РНК выделяли из зеленых частей растений по Bekesiova I. et al. 1999 [Bekesiova, 1999]. Качественное и количественное определение фитовирусов в пробах проводили одношаговой ОТ-ПЦР с флуоресцентной детекцией в реальном времени в амплификаторе QuantStudio 5 (Applied Biosystems) с использованием коммерческих наборов серии «Potato Virus X, Y, M, L, S, A, PSTVdRT» (Синтол).Результаты. В результате исследований были описаны симптомы проявления ассоциативной вирусной инфекции на сортах картофеля, в зависимости от концентрации и соотношения этих вирусов в растении. Смешанная фитовирусная инфекция на картофельном поле в Приморском крае состояла из PVY, PVX, PVA, PVS, PVM, а также PLRV и PSTVd

Математическое моделирование влияния вакцинации на распространение эпидемии COVID-19

The mathematical model based on a system of ordinary differential equations is proposed to describe the effect of the vaccination rate on the spread of the COVID-19 epidemic. The results of numerical modeling are presented for the case when vaccination begins after the beginning of the epidemic. A dimensionless vaccination parameter V was obtained, which allows one to characterize the effect of the vaccination rate on the reduction of the incidence of viral diseases with different virulence levels in a large closed population of people. Introducing this parameter allows the simulation results to be generalized to the populations of different size, different epidemic spread rate, different vaccination rate, and different vaccine efficiency. It has been shown that increasing the parameter V decreases the proportion of the sick population. It follows from our model that the vaccination influence on the spread of a respiratory viral disease such as COVID-19 decreases for a later initiation of vaccination. The simulation results should contribute to the development of optimal vaccination scenarios for the population.Предложена математическая модель на основе системы обыкновенных дифференциальных уравнений для описания влияния темпа вакцинации на распространение эпидемии типа COVID-19. Приведены результаты численного моделирования для случая, когда вакцинация начинается после начала распространения эпидемии. Получен безразмерный параметр вакцинации V, который позволяет количественно характеризовать влияние темпа вакцинации на снижение заболеваемости вирусными заболеваниями с различными уровнями вирулентности в большой замкнутой популяции людей. Введение этого параметра позволяет переносить результаты моделирования на популяции других размеров для разных скоростей распространения эпидемии, разных скоростей вакцинирования и разной эффективности вакцин. Показано, что увеличение параметра вакцинации V при прочих равных условиях приводит к снижению доли заболевшего населения. Показано также, что при постоянном темпе вакцинации ее влияние на распространение респираторного вирусного заболевания типа COVID-19 снижается при более позднем начале вакцинации. Результаты моделирования могут способствовать разработке оптимальных сценариев вакцинации населения