Hasil untuk "Periodicals"

Charles C. Elton

Casper Oelen, Bob Rink, Mattia Sensi

We study non-Birkhoff periodic orbits in symmetric convex planar billiards. Our main result provides a quantitative criterion for the existence of such orbits with prescribed minimal period, rotation number, and spatiotemporal symmetry. We exploit this criterion to find sufficient conditions for a symmetric billiard to possess infinitely many non-Birkhoff periodic orbits. It follows that arbitrarily small analytical perturbations of the circular billiard have non-Birkhoff periodic orbits of any rational rotation number and with arbitrarily long periods. We also generalize a known result for elliptical billiards to other $\mathbb{D}_2$-symmetric billiards. Lastly, we provide Matlab codes which can be used to numerically compute and visualize the non-Birkhoff periodic orbits whose existence we prove analytically.

Aya Khalil

Joseph Samaha (1949–2007) was a central figure in Arab media, particularly in Beirut. He was a journalist with the al-Safīr daily newspaper for nearly two decades, co-founder of the Parisian journal al-Yawm al-sābi‘ in 1984, and then co-founder of the daily paper al-Akhbār in 2006. He had his first experiences with activism just as he was beginning his intellectual career, in the context of the political upheaval in Lebanon following the June 1967 defeat in the Arab-Israel war. His social trajectory and his writings—dating from the 1970s up until his death—form a rich material that sheds light on the social foundations for a continuity of Arabism—Arab protonationalism—in the Arab intellectual space, despite the overall transformations characterized by the decline of the left and Arab nationalism on one hand, and the rise of Islamism on the other. This article combines an analysis of Samaha’s writings in major periodicals with that of his biographical trajectory, structured by both Beirut as an intellectual space and by transnational movements, and an analysis of the political conjuncture. In so doing, this article, drawing on socio-history of political ideas and the sociology of intellectuals, seeks to examine the social conditions for the production and circulation of Arabism, but also the shifting makeup of its ideological foundation after the defeat of 1982.

Daye Lim, Tom Van Doorsselaere, Valery M. Nakariakov et al.

Context. Recent observations of decayless transverse oscillations have shown two branches in the relationship between periods and loop lengths. One is a linear relationship, interpreted as a standing mode. The other shows almost no correlation and has not yet been interpreted conclusively. Aims. We investigated the undersampling effect on observed periods of decayless oscillations. Methods. We considered oscillating coronal loops that closely follow the observed loop length distribution. Assuming that all oscillations are standing waves, we modeled a signal that represents decayless oscillations where the period is proportional to the loop length and the amplitude and phase are randomly drawn. A downsampled signal was generated from the original signal by considering different sample rates that mimic temporal cadences of telescopes, and periods for sampled signals were analysed using the fast Fourier transform. Results. When the sampling cadence is getting closer to the actual oscillation period, a tendency for overestimating periods in short loops is enhanced. The relationship between loop lengths and periods of the sampled signals shows the two branches as in the observation. Conclusions. We find that long periods of decayless oscillations occurring in short loops could be the result of undersampling.

Fangzhou Ai, Zhuonan Lin, Jiawei Duan et al.

This work introduces an approach to compute periodic phase diagram of micromagnetic systems by solving a periodic linearized Landau-Lifshitz-Gilbert (LLG) equation using an eigenvalue solver with the Finite Element Method formalism. The linear operator in the eigenvalue problem is defined as a function of the periodic phase shift wave vector. The dispersion diagrams are obtained by solving the eigenvalue problem for complex eigen frequencies and corresponding eigen states for a range of prescribed wave vectors. The presented approach incorporates a calculation of the periodic effective field, including the exchange and magnetostatic field components. The approach is general in that it allows handling 3D problems with any 1D, 2D, and 3D periodicities. The ability to calculated periodic diagrams provides insights into the spin wave propagation and localized resonances in complex micromagnetic structures.

William Q. Erickson, Daniel Herden, Jonathan Meddaugh et al.

Given a finite simple graph $G$, let $\operatorname{M}(G)$ denote its 2-distance graph, in which two vertices are adjacent if and only if they have distance 2 in $G$. In this paper, we consider the periodic behavior of the sequence $G, \operatorname{M}(G), \operatorname{M}^2(G), \operatorname{M}^3(G), \ldots$ obtained by iterating the 2-distance operation. In particular, we classify the connected graphs with period 3, and we partially characterize those with period 2. We then study two families of graphs whose 2-distance sequence is eventually periodic: namely, generalized Petersen graphs and complete $m$-ary trees. For each family, we show that the eventual period is 2, and we determine the pre-period and the two limit graphs of the sequence.

Yehia Abdelsalam, Sankaranarayanan Subramanian, Sebastian Engell

This work proposes a new a framework for determining robust periodic invariant sets and their associated control laws for constrained uncertain linear systems. Necessary and sufficient conditions for stabilizability by periodic controllers are stated and proven using finite step Lyapunov functions for the unconstrained case. We then introduce a scenario tree interpretation of finite step Lyapunov functions for uncertain systems and show that this interpretation results in useful criteria for the design of robust stabilizing controllers. In particular, novel convex feasibility criteria for the synthesis of simple static controllers and what we call linear interpolating tree periodic controllers with memory are derived. It is proven that for a sufficiently large length of the period, a stabilizing linear interpolating tree periodic controller can always be found using the proposed criterion provided that the uncertain system is stabilizable by such controllers. In this sense, the presented synthesis method is non-conservative. The results are then extended to constrained uncertain linear systems and conditions for controllers that realize robust periodic invariant sets which are less conservative than those that result from the known methods in the literature are derived.

Annabel Biruete, Neal X. Chen, Corinne E. Metzger et al.

Abstract Chronic kidney disease (CKD)–mineral bone disorder (CKD‐MBD) leads to fractures and cardiovascular disease. Observational studies suggest beneficial effects of dietary fiber on both bone and cardiovascular outcomes, but the effect of fiber on CKD‐MBD is unknown. To determine the effect of fiber on CKD‐MBD, we fed the Cy/+ rat with progressive CKD a casein‐based diet of 0.7% phosphate with 10% inulin (fermentable fiber) or cellulose (non‐fermentable fiber) from 22 weeks to either 30 or 32 weeks of age (~30% and ~15% of normal kidney function; CKD 4 and 5). We assessed CKD‐MBD end points of biochemistry, bone quantity and quality, cardiovascular health, and cecal microbiota and serum gut‐derived uremic toxins. Results were analyzed by two‐way analysis of variance (ANOVA) to evaluate the main effects of CKD stage and inulin, and their interaction. The results showed that in CKD animals, inulin did not alter kidney function but reduced the increase from stage 4 to 5 in serum levels of phosphate and parathyroid hormone, but not fibroblast growth factor‐23 (FGF23). Bone turnover and cortical bone parameters were similarly improved but mechanical properties were not altered. Inulin slowed progression of aorta and cardiac calcification, left ventricular mass index, and fibrosis. To understand the mechanism, we assessed intestinal microbiota and found changes in alpha and beta diversity and significant changes in several taxa with inulin, together with a reduction in circulating gut derived uremic toxins such as indoxyl sulfate and short‐chain fatty acids. In conclusion, the addition of the fermentable fiber inulin to the diet of CKD rats led to a slowed progression of CKD‐MBD without affecting kidney function, likely mediated by changes in the gut microbiota composition and lowered gut‐derived uremic toxins. © 2023 The Authors. JBMR Plus published by Wiley Periodicals LLC. on behalf of American Society for Bone and Mineral Research.

Michael Borinsky, Oliver Schnetz

Feynman periods are Feynman integrals that do not depend on external kinematics. Their computation, which is necessary for many applications of quantum field theory, is greatly facilitated by graphical functions or the equivalent conformal four-point integrals. We describe a set of transformation rules that act on such functions and allow their recursive computation in arbitrary even dimensions. As a concrete example we compute all subdivergence-free Feynman periods in $φ^3$ theory up to six loops and 561 of 607 Feynman periods at seven loops. Our results support the conjectured existence of a coaction structure in quantum field theory and suggest that $φ^3$ and $φ^4$ theory share the same number content.

Shiyu Wang, Xiaojie Guo, Liang Zhao

Periodic graphs are graphs consisting of repetitive local structures, such as crystal nets and polygon mesh. Their generative modeling has great potential in real-world applications such as material design and graphics synthesis. Classical models either rely on domain-specific predefined generation principles (e.g., in crystal net design), or follow geometry-based prescribed rules. Recently, deep generative models has shown great promise in automatically generating general graphs. However, their advancement into periodic graphs have not been well explored due to several key challenges in 1) maintaining graph periodicity; 2) disentangling local and global patterns; and 3) efficiency in learning repetitive patterns. To address them, this paper proposes Periodical-Graph Disentangled Variational Auto-encoder (PGD-VAE), a new deep generative models for periodic graphs that can automatically learn, disentangle, and generate local and global graph patterns. Specifically, we develop a new periodic graph encoder consisting of global-pattern encoder and local-pattern encoder that ensures to disentangle the representation into global and local semantics. We then propose a new periodic graph decoder consisting of local structure decoder, neighborhood decoder, and global structure decoder, as well as the assembler of their outputs that guarantees periodicity. Moreover, we design a new model learning objective that helps ensure the invariance of local-semantic representations for the graphs with the same local structure. Comprehensive experimental evaluations have been conducted to demonstrate the effectiveness of the proposed method. The code of proposed PGD-VAE is availabe at https://github.com/shi-yu-wang/PGD-VAE.

Aled Gruffydd Jones

Aleksandr M. Dronov

The review analyzes the monograph by Croatian historian Branko Ostajmer Narodna stranka u Slavoniji i Srijemu 1883.–1903. [The People’s Party in Slavonia and Srem in 1883–1903] and considers the historiography, source base, structure, and content of the book. Not only does the author of the monograph contribute to the development of Croatian historiography, but he also polemicizes with his predecessors and contemporaries. The extant archival sources of the period studied by B. Ostajmer are not plentiful, so the book is largely based on periodicals. A specific feature of his work is the author’s focus on the outstanding personalities of the era associated with the activities of the People’s Party. In addition, it is necessary to highlight the author’s analysis of Slavonism, a concept that is important for understanding the period and the region under study. B. Ostajmer studies the internal organization of the party and its electorate, including the interaction with individual social and ethnic groups, as well as the activities of the party in the context of Croat-Hungarian relations. Much space in the narrative is given to the figure of Croatian Ban K. Khuen-Héderváry, whose reign was taken as the chronological framework of the work. The book can be of interest to historians of parties and social movements of the Modern Era as well as specialists in Croatia, the Balkans, and Central Europe.

Naoki Tsuji, Tomoaki Sakamoto, Kazuto Hoshi et al.

ABSTRACT Bone nodule formation by differentiating osteoblasts is considered an in vitro model that mimics bone modeling. However, the details of osteoblast behavior and matrix production during bone nodule formation are poorly understood. Here, we present a spatiotemporal analysis system for evaluating osteoblast morphology and matrix production during bone modeling in vitro via two‐photon microscopy. Using this system, a change in osteoblast morphology from cuboidal to flat was observed during the formation of mineralized nodules, and this change was quantified. Areas with high bone formation were densely populated with cuboidal osteoblasts, which were characterized by blebs, protruding structures on their cell membranes. Cuboidal osteoblasts with blebs were highly mobile, and osteoblast blebs exhibited a polar distribution. Furthermore, mimicking romosozumab treatment, when differentiated flattened osteoblasts were stimulated with BIO, a GSK3β inhibitor, they were reactivated to acquire a cuboidal morphology with blebs on their membranes and produced more matrix than nonstimulated cells. Our analysis system is a powerful tool for evaluating the cell morphology and function of osteoblasts during bone modeling. © 2022 The Authors. JBMR Plus published by Wiley Periodicals LLC on behalf of American Society for Bone and Mineral Research.

Yanhong Wang, Jiaojiao Wu, Qingning Zhang et al.

Introduction Breastfeeding provides various health benefits to both mothers and infants. Despite the efforts that have been made, breastfeeding rates remain lower than recommended worldwide. Healthcare providers often fail to provide the support women need due to various reasons such as lack of time and competency, discontinuity of care and so on. Synthesis of the primary qualitative studies exploring healthcare providers’ experience with supporting breastfeeding can provide greater insights into their perceived barriers and facilitators and further provide evidence for the implementation of interventions to improve breastfeeding services.Methods and analysis Qualitative studies exploring healthcare providers’ experiences with breastfeeding services will be searched in the following databases: PubMed, Embase, CINAHL, Scopus, ProQuest, PsycINFO, the Cochrane Library, Web of Science, China Biology Medicine disc, China National Knowledge Infrastructure, VIP Database for Chinese Technical Periodicals, Chinese Wanfang Data, ProQuest Dissertations and Theses, Open Grey collection. Studies reported in English or Chinese and conducted between January 1990 to July 2021 will be included. The Joanna Briggs Institute (JBI) Critical Appraisal Checklist for Qualitative Research will be used to assess the methodological quality of included studies. The JBI standardised data extraction tools will be used to extract data. The JBI meta-aggregation method will be used to synthesise the data. The synthesised findings will be graded finally according to the ConQual approach to establish confidence. Two authors will independently screen and select the search output, extract data, assess methodological quality and cluster findings. Any disagreements that arise between the two reviewers will be adjudicated by a third reviewer to reach a consensus.Ethics and dissemination This review will use published data, so it will not require ethical approval. The findings of this systematic review will be disseminated via an international peer-reviewed journal publication and several scientific conference presentations.PROSPERO registration number CRD42021254542.

S. A. Ruseishvili

In the article under consideration, the author examines three main waves of the Russian-speaking immigration to Brazil and, particularly, to the State of São Paulo and its capital of the same name, during the first half of the 20th century. The first wave refers to the period from 1921 to the late 1930s. We consider the arrival of general Wrangel’s soldiers and officers, in 1921; the resettlement of Russian-speaking farmers from Romanian Bessarabia in 1923-1930s; and the ‘secondary’ migration of Nansen refugees from Europe during the 1930s. The second wave represents the post-war subsidized migration of Russian displaced persons (DPs), and the third one is the resettlement of the Russians from China during the 1950s. The author relies on a vast number of authentic sources from public and private archives, such as Russian-language periodicals in Brazil, Brazilian regulatory acts, and interviews with the descendants of Russian emigrants. Delivering a comparative analysis of the aforementioned waves the author concludes that the patterns of the Russian speakers’ adaptation in Brazil need to be considered in the light of political and economic conditions in the country in a particular period of immigrants’ arrival. It is also noted that anti-Soviet sentiments in Brazilian politics, starting from the mid-1930s, had a negative impact on preservation of the Russian language and Russian culture in the country.

Mayerli Andrea Fernández-Rojas

El objetivo de la investigación es analizar los estilos de comunicación para abordar el conflicto que utilizan los estudiantes del grado sexto de la Institución Educativa Bordones, a fin de diseñar una ruta que permita una transformación; comprender el conflicto, como las diferencias que se pueda presentar en las relaciones que establecen dos o más personas, el cual puede ser resuelto de diferentes formas, siendo la comunicación, el medio más adecuado. El estudio se enmarca en el paradigma cualitativo, con enfoque sociocrítico e investigación acción como el tipo de diseño aplicado. Los resultados evidencian que el estilo de comunicación más utilizado por los estudiantes, pese a que comprenden que no es el más adecuado, es el agresivo, que se manifiesta en el uso de vocabulario soez, gritos, insultos, apodos, como parte natural de las relaciones y como una forma de abordar el conflicto.

Rafael Molina-Venegas, Miguel Ángel Rodríguez, Manuel Pardo-de-Santayana et al.

Humanity faces the challenge of conserving the attributes of biodiversity that may be essential to secure human wellbeing. Among all the organisms that are beneficial to humans, plants stand out as the most important providers of natural resources. Therefore, identifying plant uses is critical to preserve the beneficial potential of biodiversity and to promote basic and applied research on the relationship between plants and humans. However, much of this information is often uncritical, contradictory, of dubious value or simply not readily accessible to the great majority of scientists and policy makers. Here, we compiled a genus-level dataset of plant-use records for all accepted vascular plant taxa (13489 genera) using the information gathered in the 4th Edition of Mabberley's plant-book, the most comprehensive global review of plant classification and their uses published to date. From 1974 to 2017 all the information was systematically gathered, evaluated, and synthesized by David Mabberley, who reviewed over 1000 botanical sources including modern Floras, monographs, periodicals, handbooks, and authoritative websites. Plant uses were arranged across 28 standard categories of use following the Economic Botany Data Collection Standard guidelines, which resulted in a binary classification of 9478 plant-use records pertaining human and animal nutrition, materials, fuels, medicine, poisons, social and environmental uses. Of all the taxa included in the dataset, 33% were assigned to at least one category of use, the most common being "ornamental" (26%), "medicine" (16%), "human food" (13%) and "timber" (8%). In addition to a readily available binary matrix for quantitative analyses, we provide a control text matrix that links the former to the description of the uses in Mabberley's plant-book. We hope this dataset will serve to establish synergies between scientists and policy makers interested in plant-human interactions and to move towards the complete compilation and classification of the nature's contributions to people upon which the wellbeing of future generations may depend.

Farrokh Habibzadeh

Hearing about the selection of one’s journal by a reputable indexing system pleases every editor. Journals with an international editorial members selected from prolific researchers have a higher chance of being selected by a prestigious indexing system. Geographic distribution of authors’ affiliations is another important factor. Considering a minimum of internationally acceptable editorial standards would also influence the decision of the indexing systems to select a journal—publishing few quality articles is much better than publishing a bunch of poorly designed badly reported ones. The key to success is having a group of dedicated staff with good communication skills.

Genki Shibukawa

We give a simple proof of some explicit formulas of periodic continuants by Chebyshev polynomials of the second kind given by Rozsa.

Roman D. Timenchik

The article from the author's cycle “From the Index to Akhmatova's Notebooks” (published in various periodicals) demonstrates the attempt of an extensive commentary on Akhmatova's working notes, organized around the characters present on the pages of her notebooks, a kind of free Akhmatova encyclopedia, where different periods of her long life are combined in the onomasticon. A comment of this kind snatches out representative fragments of Akhmatova's epoch, but the degree of presence of different persons in the list, or even their absence, does not always reflect their weight in Akhmatova's biography. The present article is devoted to the People's Commissar of Internal Affairs, the General Commissar of State Security Genrikh Yagoda, mentioned not only in the Notebooks, but also in the Diary Pages and in Akhmatova's satirical couplets of the 1930s.