Hasil untuk "Periodicals"

Adam Skowyrski

Following methods used by A. Dugas for investigating derived equivalent pairs of (weakly) symmetric algebras, we apply them in a specific situation, obtaining new deep results concerning iterated mutations of symmetric periodic algebras. More specifically, for any symmetric algebra $Λ$, and an arbitrary vertex $i$ of its Gabriel quiver, one can define mutation $μ_i(Λ)$ of $Λ$ at vertex $i$ via silting mutation of the stalk complex $\La$. Then $μ_i(Λ)$ is again symmetric, and we can iterate this process. We want to understand the order of $μ_i$, in case the vertex $i$ is $d$-periodic, i.e. the simple module $S_i$ associated to $i$ is periodic of period $d$ (with respect to the syzygy). The main result of this paper shows that then $μ_i$ has order $d-2$, that is $μ_i^{d-2}(Λ)\congΛ$ (modulo socle), under some additional assumption on the (periodic) projective-injective resolution of $S_i$. Besides, we present briefly some consequences concerning arbitrary periodic vertex and give few sugestive examples showing that this property should hold in general, i.e. without restrictions on the periodic projective resolution.

Rajeev Singh Rathour, Radosław Smolec, Gergely Hajdu et al.

Classical Cepheids are not only excellent standard candles, but also invaluable tools to test stellar evolution and pulsation theories. Rates of their pulsation period change, quantified usually through $O-C$ diagrams, can be confronted with predictions of stellar evolution theory. On the other hand, period changes on much shorter time scales ($\sim$10$^{2}$-10$^{4}$days), attributed to non-evolutionary effects are often detected and lack detailed explanation. We aim to provide a systematic and quantitative description of irregular or non-linear period changes in Cepheids. We aim to provide a systematic and quantitative description of irregular or non-linear period changes in Cepheids. We analysed part of the OGLE data for classical Cepheids in the Magellanic Clouds (MCs; from both Large Magellanic Cloud, LMC, and the Small Magellanic Cloud, SMC) using the modified Hertzsprung $O-C$ technique. A sample of 3658 stars, with the best quality data and void of additional low-amplitude periodicities (e.g. due to non-radial pulsations), that could impact the results, was selected for analysis. Based on $O-C$ shapes, stars were classified into three categories: no period change (class 1), linear period change (class 2), and irregular change (class 3). In our investigation, $33.5\pm0.7$\% of analysed stars show irregular period changes. Considering the pulsation mode, irregular period changes were detected in $16.5\pm0.7$\% of the analysed fundamental mode stars and in $68.1\pm1.2$\% of the first overtone stars. The amplitude of variability in the $O-C$ diagrams increases with the pulsation period, and at a given pulsation period, it is larger for first overtone stars. While the increase is linear for first overtone stars, for fundamental mode stars it becomes steeper as the pulsation period increases.

Annika Kängsepp

The variation in the case forms of the indefinite pronoun keegi ‘someone’ in written Estonian There is variation in the case forms of the indefinite pronouns keegi ‘someone’, miski ‘something’, kumbki ‘either’ and ükski ‘none’ in Estonian. In these pronouns, -gi/-ki can appear after the case ending (e.g., kellelegi), as specified in the standard language norm; before the case ending (e.g., kellegile); between two case endings (e.g., kellelegile); or both before and after the case ending (e.g., kellegilegi). In this article, I used data from the Estonian National Corpus 2021 to provide an overview of the extent of variation in the case forms of keegi, miski, kumbki and ükski, and to describe the factors influencing the variation in the case forms of the pronoun keegi. The results indicate that for all four pronouns, -gi/-ki is most commonly placed after the case ending, accounting for 85.3% of all occurrences. The second most common forms are those where -gi/-ki precedes the case ending, making up 14.1% of occurrences. A univariate analysis conducted to identify the factors influencing this variation showed that genre, the occurrence of the pronoun as an attribute, and the function of the pronoun in a clause significantly influenced the variation of case forms. A multivariate analysis indicated that genre – and, consequently, the impact of editing – was most strongly associated with the variation. In genres such as blogs and periodicals, which are typically edited, -gi/-ki is predominantly placed after the case ending. Conversely, in forums, which are often unedited, it is more common for -gi/-ki to appear before the case ending, between two case endings, or both before and after the case ending.

Maxim V. Skorokhodov

The article reveals the main milestones of Konstantin G. Paustovsky’s creative cooperation with the editors of the journals “Znamya” and “Novyi Mir,” in which The Story of a Life was published. Identified and briefly characterized lifetime printed sources of the text of three chapters of the sixth part of The Story of a Life — “On Low Heat (The Book of Wanderings)”: “The Fourth Strip,” “January Cold” (“The Cold”) and “Night Trains.” The article identifies and characterizes the discrepancies in the named chapters and hypothesizes about the reasons for their occurrence. The novelist, having published individual chapters in periodicals and then the whole work in the journal “Novyi Mir,” continued to work on the text by expanding or clarifying the characters’ features, correcting descriptions, and adding or removing epithets. In many cases, after publication in the journal “Novyi Mir,” the preparation of which was not without editorial intervention, Paustovsky returned to the original version, sometimes making minor editorial corrections. The article introduces new sources into the scientific circulation, including letters addressed to the writer containing statements about the sixth part of The Story of a Life.

Salnikova Ekaterina

The article is based on the transcript of the discussion on the work of the popular illustrated magazine Sovetsky Ekran (The Soviet Screen) and the materials of the issues of 1957 and 1958. This array of texts and illustrative materials has not been previously studied and analysed in the humanities, which determines the substantial novelty of the research. The relevance of this topic is due to the need to comprehend the Soviet experience of periodicals on cinema associated with a wide range of authors — journalists, film critics, historians, and film theorists. The purpose of the article is to identify the sentiment of the meeting participants on the ideological discourse and their professional circle. The author compares the discussions with the specifics of articles and photo reports on the pages of Sovetsky Ekran, traces the development of behavioural patterns and rhetorical formulas during the meeting, and puts the issues under discussion in the context of the development of criticism, film studies, attitudes to cinematography as the ‘auteur’ film aesthetics and the entertaining, ‘light’ formats. This allows us to analyse the trends of self-positioning of film industry professionals, film critics, and film historians and to see the complexity of their relationship with the ideological system. The author notes the combination of Thaw tendencies with the speakers, their appeal to the concept of friendship, the desire to defend the interests of film professionals and the interests and values of wide circles of intelligentsia. Symbolism is associated with digressions from the official agenda of the meeting. The speeches regularly feature memories of the 1920s and the references to the topic of foreign countries and foreign cinema life. There is an obvious interest in turning the magazine into a platform for professional film studies. Conclusions are drawn about the underlying reluctance to discuss cinema and magazine business from the standpoint of ideology, about the desire of the intelligentsia to strengthen their cultural influence, and about the cinematographers’ rejection of the need to satisfy mass tastes through light, entertaining magazine materials.

Paola Andrea Ayala-Burbano, Jhon Jairo Paz

En Colombia el cáncer cérvico-uterino (CCU) es la primera causa de muerte por neoplasias malignas en la mujer. El principal agente causal es el virus papiloma humano (VPH). La probabilidad de desarrollar lesiones precancerosas en etapas iniciales podría incrementarse debido a la exposición temprana a factores de riesgo, especialmente en poblaciones vulnerables como las adolescentes del municipio de Ricaurte, Nariño. En este sentido, este estudio se centró describir el grado de conocimiento que tienen un grupo de adolescentes de dos instituciones educativas del municipio de Ricaurte, sobre la infección por VPH, CC, y su relación con la conducta preventiva. Además, fue implementado un modelo de intervención formativa que integró estrategias de prevención primaria relacionados a la promoción de hábitos saludables. Los resultados de este estudio revelaron que solo una minoría de las adolescentes encuestadas estaba familiarizada con el CCU (31.5%). Además, el inicio temprano de la actividad sexual fue identificado como un factor de riesgo de CCU. Sin embargo, el un elevado porcentaje de adolescentes (73.7%) habían recibido al menos una dosis de la vacuna contra el VPH.  En cuanto a las medidas preventivas, el 90.3% de la población carecía de conocimiento sobre cualquier método preventivo, y además el 78% no había recibido ningún examen ginecológico para la realización de la citología. La intervención implementada, no solo aumentó el nivel de conocimiento sobre el cáncer de cuello uterino entre las adolescentes, sino que también les brindó las herramientas necesarias para tomar decisiones informadas y promover su bienestar a largo plazo.

Olga Anosova, Vitaliy Kurlin

Periodic Geometry studies isometry invariants of periodic point sets that are also continuous under perturbations. The motivations come from periodic crystals whose structures are determined in a rigid form but any minimal cells can discontinuously change due to small noise in measurements. For any integer k>=0, the density function of a periodic set S was previously defined as the fractional volume of all k-fold intersections (within a minimal cell) of balls that have a variable radius t and centers at all points of S. This paper introduces the density functions for periodic sets of points with different initial radii motivated by atomic radii of chemical elements and by continuous events occupying disjoint intervals in time series. The contributions are explicit descriptions of the densities for periodic sequences of intervals. The new densities are strictly stronger and distinguish periodic sequences that have identical densities in the case of zero radii.

Sergii Favorov

Based on the properties of distributions and measures with discrete support, we investigate temperate almost periodic distributions on the Euclidean space and connection with their Fourier transforms. We also study relations between the Fourier transform of almost periodic distributions and their Fourier coefficients. The main result of the article is the construction of a crystalline measure on the real line, which is neither almost periodic distribution, nor a Fourier quasicrystal.

Bethany E. Qualls

Guevara, L. Glass, A. Shrier

Mengjiao Liang, Ling Guo, Jing Huo et al.

<h4>Objectives</h4>To review cross-sectional studies on the prevalence of sleep disturbance in Chinese adolescents and use a meta-analysis to explore the factors that may explain the heterogeneity between estimates of the prevalence.<h4>Methods</h4>We followed the Preferred Reporting Items for Systematic Review and Meta-analysis and searched the PubMed, Embase, Cochrane Library, PsycINFO, Scopus, Web of Science, SinoMed, Chinese National Knowledge Infrastructure (CNKI), WanFang, and VIP Database for Chinese Technical Periodicals databases from their inception through June 30, 2020. Analysis of the abstract, full-text, and data were conducted independently with uniform standards. Sub-group analyses and meta-regression analyses were performed to explore the associations between prevalence and gender, sex ratio, mean age, area, studying stage, sample size, survey time, response rate, assessment tools, PSQI cut-off, and quality score of the study.<h4>Results</h4>A total of 63 studies (64 groups of outcomes) were included in our analysis, covering 430,422 adolescents across China, of which 104,802 adolescents had sleep disturbances. The overall pooled prevalence was 26% (95% CI: 24-27%). Adolescents in senior high school (28%, 95% CI: 24-31%, p<0.001) had a higher prevalence of sleep disturbances than those in junior high school (20%, 95% CI: 15-24%, p<0.001). Studies with effective sample size of more than 1,000 and less than 3,000 had the highest prevalence of 30% (95% CI: 24-35%, p<0.001). The prevalence of sleep disturbances was not affected by other factors.<h4>Conclusion</h4>This systematic review and meta-analysis revealed that sleep disturbances are common in Chinese adolescents, and effective psychological and behavior intervention may be needed to help adolescents solve their sleep problems.

E. B. Galkin, S. S. Repin

Thousand nine hundred seventeenth year is one of the rubezhnykh of dates in national history. There is no such field of activity which would be not affected by rough and fatal events of this year.

A. I. Chubarov

The history of the creation and activity of student labor brigades on the territory of the Russian Empire is considered. They were supposed to replace men in peasant farms who had been mobilized into the ranks of the army. By the early 20th century, the agrarian Russian Empire was characterized by an excess of workers in the countryside, since a significant part of the country’s population lived in the countryside. The ruling circles of both Russia and the European powers were confident in the “inexhaustibility” of the human resources of the Russian state. However, already in the summer and autumn of 1914, a shortage of workers in rural areas began to be felt. With the subsequent mobilizations, the situation only worsened. In response to the problem, the tsarist government asked the local authorities to help the families of the mobilized lower ranks in harvesting and sowing fields. We use materials from periodicals and primary materials deposited in the archives of the cities of the Central Black Earth region about student labor brigades of the Voronezh, Kursk and Oryol Governorates. We also use information on other regions of the Russian Empire. It is assumed that labor brigades arose on a private initiative as one of the forms of mobilization of labor resources in conditions caused by a shortage of workers. Later, the initiative of educational institutions of the Minsk province received state support.

Xueda Wen, Ruihua Fan, Ashvin Vishwanath et al.

In this paper and its sequel, we study non-equilibrium dynamics in driven 1+1D conformal field theories (CFTs) with periodic, quasi-periodic, and random driving. We study a soluble family of drives in which the Hamiltonian only involves the energy-momentum density spatially modulated at a single wavelength. The resulting time evolution is then captured by a Möbius coordinate transformation. In this Part I, we establish the general framework and focus on the first two classes. In periodically driven CFTs, we generalize earlier work and study the generic features of entanglement/energy evolution in different phases, i.e. the heating, non-heating phases and the phase transition between them. In quasi-periodically driven CFTs, we mainly focus on the case of driving with a Fibonacci sequence. We find that (i) the non-heating phases form a Cantor set of measure zero; (ii) in the heating phase, the Lyapunov exponents (which characterize the growth rate of the entanglement entropy and energy) exhibit self-similarity, and can be arbitrarily small; (iii) the heating phase exhibits periodicity in the location of spatial structures at the Fibonacci times; (iv) one can find exactly the non-heating fixed point, where the entanglement entropy/energy oscillate at the Fibonacci numbers, but grow logarithmically/polynomially at the non-Fibonacci numbers; (v) for certain choices of driving Hamiltonians, the non-heating phases of the Fibonacci driving CFT can be mapped to the energy spectrum of electrons propagating in a Fibonacci quasi-crystal. In addition, another quasi-periodically driven CFT with an Aubry-André like sequence is also studied. We compare the CFT results to lattice calculations and find remarkable agreement.

Y. Meir, N. Wingreen, P. Lee

Takashi Mori

It is proved that the energy absorption in a periodically driven classical spin system is exponentially slow in frequency, which results in a two-step relaxation called the Floquet prethermalization. This result is shown by establishing the classical limit of the quantum spin dynamics. The Floquet prethermal state is well described by the Gibbs ensemble with respect to the static effective Hamiltonian obtained by a truncation of the Floquet-Magnus expansion. On the other hand, the same effective Hamiltonian does not reproduce the local dynamics for an exponentially long time. This is due to the chaoticity of classical dynamics, and in stark contrast to quantum spin systems, in which the effective Hamiltonian well reproduces the exact quantum dynamics up to an exponentially long time.

D. Braga, F. Grepioni

Jason A. C. Gallas

We show that several orbital equations and orbital clusters of the quadratic (logistic) map coincide surprisingly with cyclotomic {\it period equations}, polynomials whose roots are Gaussian periods. An analytical expression for the field discriminant of period equations is obtained and applied to discover and to fill gaps in number field databases constructed by numerical search processes. Such expression allows easy assess to inessential divisors of conventional discriminants and sheds light into why numerical construction of databases is a hard problem. It also provides significant information about the organization of periodic orbits of the quadratic map.

Iván Gabriel Grajales-Melián, Yessy Villavicencio-Simón

Entre las líneas rectoras del proyecto “El patrimonio literario de Santiago de Cuba (siglos XIX, XX y XXI): Valoración crítica”, de la Facultad de Humanidades de la Universidad de Oriente, se encuentra la necesidad de emprender pesquisas reveladoras del legado literario en la antigua capital del Departamento Oriental. Tales trabajos demandan la recuperación de un valioso patrimonio cultural, disgregado en salas bibliotecarias de fondos raros, de difícil acceso, los cuales contribuyen a visibilizar espacios preteridos de la ciencia literaria cubana, que complementan los accesibles en las referencias nacionales más conocidas. El artículo presenta las fuentes documentales para el estudio de la crítica literaria en publicaciones periódicas y culturales de Santiago de Cuba entre 1825 y 1895. Este forma parte de una investigación doctoral insertada en el proyecto referido que interviene en la delimitación de las singularidades de la crítica literaria periodística en la región oriental.

Agata ZIÓŁKOWSKA

One of the most basic functions of the state is to ensure the security to it and its citizens. Significant elements are: perseverance, political independence, territorial integrity and maintenance proper level of life quality. Today’s intelligence, which is part of the structures of security organs, belongs to the elite part of the special forces performing strategic goals. Therefore, acquiring the information by OSINT is important not only for the institution itself but also for citizens. OSINT is one of the means by which security is provided to the internal and external states. Open source information is one of the agents of economic, political, military, etc. Books, periodicals, statistical yearbooks, social networking sites and daily newspapers belong to the basic, verified sources. In globalized world, OSINT has particular importance because, due to the obtained information, the state can take defensive action. In this article, the author pointed out the use of OSINT in the military diagnosis.