1,708 research outputs found

    Isoperiodic deformations of the acoustic operator and periodic solutions of the Harry Dym equation

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    We consider the problem of describing the possible spectra of an acoustic operator with a periodic finite-gap density. We construct flows on the moduli space of algebraic Riemann surfaces that preserve the periods of the corresponding operator. By a suitable extension of the phase space, these equations can be written with quadratic irrationalities.Comment: 15 page

    DNA double-strand breaks induced by high NaCl occur predominantly in gene deserts

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    High concentration of NaCl increases DNA breaks both in cell culture and in vivo. The breaks remain elevated as long as NaCl concentration remains high and are rapidly repaired when the concentration is lowered. The exact nature of the breaks, and their location, has not been entirely clear, and it has not been evident how cells survive, replicate, and maintain genome integrity in environments like the renal inner medulla in which cells are constantly exposed to high NaCl concentration. Repair of the breaks after NaCl is reduced is accompanied by formation of foci containing phosphorylated H2AX (Ξ³H2AX), which occurs around DNA double-strand breaks and contributes to their repair. Here, we confirm by specific comet assay and pulsed-field electrophoresis that cells adapted to high NaCl have increased levels of double-strand breaks. Importantly, Ξ³H2AX foci that occur during repair of the breaks are nonrandomly distributed in the mouse genome. By chromatin immunoprecipitation using anti-Ξ³H2AX antibody, followed by massive parallel sequencing (ChIP-Seq), we find that during repair of double-strand breaks induced by high NaCl, Ξ³H2AX is predominantly localized to regions of the genome devoid of genes (β€œgene deserts”), indicating that the high NaCl-induced double-strand breaks are located there. Localization to gene deserts helps explain why the DNA breaks are less harmful than are the random breaks induced by genotoxic agents such as UV radiation, ionizing radiation, and oxidants. We propose that the universal presence of NaCl around animal cells has directly influenced the evolution of the structure of their genomes

    Quantitative magnetotail characteristics of different magnetospheric states

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    Quantitative relationships allowing one to compute the lobe magnetic field, flaring angle and tail radius, and to evaluate magnetic flux based on solar wind/IMF parameters and spacecraft position are obtained for the middle magnetotail, <i>X</i>=(–15,–35)<i>R<sub>E</sub></i>, using 3.5 years of simultaneous Geotail and Wind spacecraft observations. For the first time it was done separately for different states of magnetotail including the substorm onset (SO) epoch, the steady magnetospheric convection (SMC) and quiet periods (Q). In the explored distance range the magnetotail parameters appeared to be similar (within the error bar) for Q and SMC states, whereas at SO their values are considerably larger. In particular, the tail radius is larger by 1–3 <i>R<sub>E</sub></i> at substorm onset than during Q and SMC states, for which the radius value is close to previous magnetopause model values. The calculated lobe magnetic flux value at substorm onset is ~1GWb, exceeding that at Q (SMC) states by ~50%. The model magnetic flux values at substorm onset and SMC show little dependence on the solar wind dynamic pressure and distance in the tail, so the magnetic flux value can serve as an important discriminator of the state of the middle magnetotail.<br><br> <b>Key words.</b> Magnetospheric physics (solar windmagnetosphere- interactions, magnetotail, storms and substorms

    ΠœΡ‹ΡˆΠ΅Ρ‡Π½Π°Ρ организация ΠΏΡ€ΠΈΠΊΡ€Π΅ΠΏΠΈΡ‚Π΅Π»ΡŒΠ½ΠΎΠ³ΠΎ ΠΎΡ€Π³Π°Π½Π° Lamellodiscus (Monogenea: Diplectanidae)

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    ΠŸΡ€ΠΈ ΠΏΠΎΠΌΠΎΡ‰ΠΈ окраски ΠΌΡ‹ΡˆΡ† флуорСсцСнтно ΠΌΠ΅Ρ‡Π΅Π½Ρ‹ΠΌ Ρ„Π°Π»Π»ΠΎΠΈΠ΄ΠΈΠ½ΠΎΠΌ ΠΈ ΠΊΠΎΠ½Ρ„ΠΎΠΊΠ°Π»ΡŒΠ½ΠΎΠΉ микроскопии ΠΈΠ·ΡƒΡ‡Π΅Π½Π° организация мускулатуры Π³Π°ΠΏΡ‚ΠΎΡ€Π° Ρƒ Π΄Π²ΡƒΡ… Π²ΠΈΠ΄ΠΎΠ² ΠΌΠΎΠ½ΠΎΠ³Π΅Π½Π΅ΠΉ ΠΈΠ· сСмСйства Diplectanidae, относящихся ΠΊ Ρ€ΠΎΠ΄Ρƒ Lamellodiscus (L. fraternus ΠΈ L. elegans), ΠΈ ΠΏΡ€ΠΎΠ²Π΅Π΄Π΅Π½ΠΎ Π΅Π΅ сравнСниС с мускулатурой Π³Π°ΠΏΡ‚ΠΎΡ€Π° Ρƒ Ρ€Π°Π½Π΅Π΅ исслСдованных прСдставитСлСй Π΄ΠΈΠΏΠ»Π΅ΠΊΡ‚Π°Π½ΠΈΠ΄ ΠΈΠ· Ρ€ΠΎΠ΄Π° Diplectanum. ИсслСдованиС ΠΏΠΎΠΊΠ°Π·Ρ‹Π²Π°Π΅Ρ‚ Π²ΠΎΠ·ΠΌΠΎΠΆΠ½ΠΎΡΡ‚ΡŒ использования особСнностСй ΠΎΡ€Π³Π°Π½ΠΈΠ·Π°Ρ†ΠΈΠΈ мускулатуры Π³Π°ΠΏΡ‚ΠΎΡ€Π° Π² систСматикС Π΄ΠΈΠΏΠ»Π΅ΠΊΡ‚Π°Π½ΠΈΠ΄

    β€œSiena Case”: the Political Development of the Siena of the Renaissance in Historiography of the Second Half of XX-XXI Centuries

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    The basic approaches to the study of the political development and government of Siena, one of the Italian republics of the Renaissance, are examined. The works of Western, especially Italian, historians of the second half of the XX - beginning of the XXI centuries are analyzed. The novelty of the study is that the author summarizes the results of studying the problem, shows the evolution of approaches to its solution, introduces the reader to modern views on it. An urgent question about the specifics of the Renaissance state by the example of the formation of Siena statehood in the second half of the XIV - first half of the XVI centuries has been raised. Based on a study of the works touching upon this problem, the author shows that during the study period the issue of the features of Siena’s political and state development was considered from different perspectives and underwent evolution from the problem of the decline of Siena to the problems of autonomy of the Siena state within the β€œMedici state”. Analysis of Western historiography of this period leads the author to agree with the conclusions of Italian scientists that the formation of a system of β€œparties” and coalition governments in Siena determines not only the relatively late formation of Signoria Petrucci, but also the specifics of Siena’s political and state development a kind of historical alternative to the Florentine signoria

    Protein Tracking by CNN-Based Candidate Pruning and Two-Step Linking with Bayesian Network

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    Protein trafficking plays a vital role in understanding many biological processes and disease. Automated tracking of protein vesicles is challenging due to their erratic behaviour, changing appearance, and visual clutter. In this paper we present a novel tracking approach which utilizes a two-step linking process that exploits a probabilistic graphical model to predict tracklet linkage. The vesicles are initially detected with help of a candidate selection process, where the candidates are identified by a multi-scale spot enhancing filter. Subsequently, these candidates are pruned and selected by a light weight convolutional neural network. At the linking stage, the tracklets are formed based on the distance and the detection assignment which is implemented via combinatorial optimization algorithm. Each tracklet is described by a number of parameters used to evaluate the probability of tracklets connection by the inference over the Bayesian network. The tracking results are presented for confocal fluorescence microscopy data of protein trafficking in epithelial cells. The proposed method achieves a root mean square error (RMSE) of 1.39 for the vesicle localisation and of 0.7 representing the degree of track matching with ground truth. The presented method is also evaluated against the state-of-the-art β€œTrackmateβ€œ framework

    Introduction to Dynamic Linear Models for Time Series Analysis

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    Dynamic linear models (DLM) offer a very generic framework to analyse time series data. Many classical time series models can be formulated as DLMs, including ARMA models and standard multiple linear regression models. The models can be seen as general regression models where the coefficients can vary in time. In addition, they allow for a state space representation and a formulation as hierarchical statistical models, which in turn is the key for efficient estimation by Kalman formulas and by Markov chain Monte Carlo (MCMC) methods. A dynamic linear model can handle non-stationary processes, missing values and non-uniform sampling as well as observations with varying accuracies. This chapter gives an introduction to DLM and shows how to build various useful models for analysing trends and other sources of variability in geodetic time series.Comment: A chapter submitted to a book with a proposed title: Geodetic Time Series Analysis and Applications, editors. J.-P. Montillet and M. Bo
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