290 research outputs found

    On the nature of the solar-wind-Mars interaction

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    Plasma measurements near Mars on the U.S.S.R. Mars-2, -3, and -5 spacecraft are considered. The data are compared with simultaneous magnetic measurements. Strong evidence is obtained in favor of a direct interaction and mass exchange between the solar wind plasma and the gaseous envelope of Mars

    Simulation of the Neutral Particle Converter of the ARIES-L Device

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    AbstractThis paper presents the concept of Lunar regolith surface layer composition analysis using solar wind bombardment and registration of the sputtered and knocked out atoms converted into ions with solid-state converters and subsequent registration of ions by high-aperture electrostatic analyzer. Monte Carlo binary collision approximation code is used to calculate angular and energy distributions of scattered and sputtered atoms. Literature data are used for evaluation of charged fractions of scattered and sputtered components and SIMION code is used for calculation of charged particles trajectories in electrostatic deflector. The total sensitivity of the proposed scheme is evaluated

    Review of the monograph “The Arctic: a Development Strategy”

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    The review emphasizes the key features of the monograph “The Arctic: Development Strategy”, prepared by experts of the Council for the Study of Productive Forces of the Ministry of Economic Development of Russia and NArFU named after M.V. Lomonosov. The authors developed a systematic analysis of the development issues of the Russian Arctic and the state development efforts in this macro-region. They studied the preferential regimes of economic activities and the role of mineral resource centers as important drivers of socio-economic development. According to the reviewer, the monograph is of interest both to specialists and to a wide range of readers

    The Structure of Martian Magnetosphere at the Dayside Terminator Region as Observed on MAVEN Spacecraft

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    We analyzed 44 passes of the MAVEN spacecraft through the magnetosphere, arranged by the angle between electric field vector and the projection of spacecraft position radius vector in the YZ plane in MSE coordinate system (θ{\theta} E ). All passes were divided into 3 angular sectors near 0{\deg}, 90{\deg} and 180{\deg} θ{\theta} E angles in order to estimate the role of IMF direction in plasma and magnetic properties of dayside Martian magnetosphere. The time interval chosen was from January 17 through February 4, 2016 when MAVEN was crossing the dayside magnetosphere at SZA ~ 70{\deg}. Magnetosphere as the region with prevailing energetic planetary ions is always found between the magnetosheath and the ionosphere. 3 angular sectors of dayside interaction region in MSE coordinate system with different orientation of the solar wind electric field vector E = -1/c V x B showed that for each sector one can find specific profiles of the magnetosheath, the magnetic barrier and the magnetosphere. Plume ions originate in the northern MSE sector where motion electric field is directed from the planet. This electric field ejects magnetospheric ions leading to dilution of magnetospheric heavy ions population, and this effect is seen in some magnetospheric profiles. Magnetic barrier forms in front of the magnetosphere, and relative magnetic field magnitudes in these two domains vary. The average height of the boundary with ionosphere is ~530 km and the average height of the magnetopause is ~730 km. We discuss the implications of the observed magnetosphere structure to the planetary ions loss mechanism.Comment: 24 pages, 13 figure

    Revisiting the models of vibration screening process

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    This talk presents two approaches for modeling of the vibration screening process. The first approach is analytical. It models the screening process as a diffusion of undersize fraction taking into account the special term for vibration separation (the Brazil nut effect). The talk provides a solution of the corresponding partial differential equation. The solution in turn allows estimation of the screening performance dependence on both deterministic and stochastic factors as well as evaluation of the factors dominance conditions. The talk presents simple evaluation formulae for the screening process performance. The second approach is based on a simulation model. The model deals with monolayer dynamics. Embodying traditional concepts of vibration transportation, the approach introduces some novel techniques of evaluation of the effect of the granular particles shape. Taking into account the particle shape factor may significantly improve the modeling precision for nonspherical particles

    Perceived Sound Quality Dimensions Influencing Frequency-Gain Shaping Preferences for Hearing Aid-Amplified Speech and Music

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    © The Author(s) 2021. Hearing aids are typically fitted using speech-based prescriptive formulae to make speech more intelligible. Individual preferences may vary from these prescriptions and may also vary with signal type. It is important to consider what motivates listener preferences and how those preferences can inform hearing aid processing so that assistive listening devices can best be tailored for hearing aid users. Therefore, this study explored preferred frequency-gain shaping relative to prescribed gain for speech and music samples. Preferred gain was determined for 22 listeners with mild sloping to moderately severe hearing loss relative to individually prescribed amplification while listening to samples of male speech, female speech, pop music, and classical music across low-, mid-, and high-frequency bands. Samples were amplified using a fast-acting compression hearing aid simulator. Preferences were determined using an adaptive paired comparison procedure. Listeners then rated speech and music samples processed using prescribed and preferred shaping across different sound quality descriptors. On average, low-frequency gain was significantly increased relative to the prescription for all stimuli and most substantially for pop and classical music. High-frequency gain was decreased significantly for pop music and male speech. Gain adjustments, particularly in the mid- and high-frequency bands, varied considerably between listeners. Music preferences were driven by changes in perceived fullness and sharpness, whereas speech preferences were driven by changes in perceived intelligibility and loudness. The results generally support the use of prescribed amplification to optimize speech intelligibility and alternative amplification for music listening for most listeners

    Screening the Pathogen Box for Identification of New Chemical Agents with Anti-Fasciola hepatica Activity

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    Fascioliasis is an infectious parasitic disease distributed globally and caused by the liver fluke Fasciola hepatica or F. gigantica. This neglected tropical disease affects both animals and humans, and it represents a latent public health problem due to the significant economic losses related to its effects on animal husbandry. For decades, triclabendazole has been the unique anti-Fasciola drug that can effectively treat this disease. However, triclabendazole resistance in fascioliasis has more recently been reported around the world, and thus, the discovery of novel drugs is an urgent need. The aim of this study was to investigate the fasciocidal properties of 400 compounds contained in the Pathogen Box. The first stage of the screening was carried out by measuring the fasciocidal activity on metacercariae at a concentration of 33 mu M each compound (the standard dose). Subsequently, the activities of the most active compounds (n = 33) at their 50% inhibitory concentration (IC50) values against metacercariae were assayed, and the results showed that 13 compounds had IC(50)s of 50%. Four hit compounds were selected on the basis of their predicted nontoxic properties, and the IC50 values obtained for adult worms were <10 mu M; thus, these compounds represented the best fasciocidal compounds tested here. A cytotoxicity assay on four types of cell lines demonstrated that three compounds were nontoxic at their most active concentration. In conclusion, three hit compounds identified in this proof-of-concept study are potential candidates in the discovery of new fasciocidal drugs. Further studies are warranted

    Co-silencing of human Bub3 and dynein highlights an antagonistic relationship in regulating kinetochore-microtubule attachments

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    We previously reported that the spindle assembly checkpoint protein Bub3 is involved in regulating kinetochore-microtubule (KT-MT) attachments. Also, Bub3 was reported to interact with the microtubule motor protein dynein. Here we examined how this interaction contributes to KT-MT attachments. Depletion of Bub3 or dynein induced misaligned chromosomes, consistent with their role in KT-MT attachments. Unexpectedly, co-silencing of both proteins partially suppressed the misalignment phenotype and restored chromosome congression. Consistent with these observations, KT-MT attachments in co-depleted cells were stable, able to drive chromosome congression, and produce inter-and intra-kinetochore stretch, indicating they are functional. We suggest that a mutual antagonism exists between Bub3 and dynein to ensure optimal KT-MT attachments. (C) 2015 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.CESPU [02-GCQF-CICS-2011N]; FCT - Fundacao para a Ciencia e a Tecnologia [CEQUIMED-PEst-OE/SAU/UI4040/2014]; FCT [SFRH/BD/90744/2012]info:eu-repo/semantics/publishedVersio
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