Article
Physics, Multidisciplinary
Emil S. Martiny, Mogens H. Jensen, Mathias S. Heltberg
Summary: This article presents a method for detecting the presence of limit cycles in stochastic systems. Statistical measures are proposed to analyze one-dimensional time series inputs and the method is tested on chemical network models.
PHYSICA A-STATISTICAL MECHANICS AND ITS APPLICATIONS
(2022)
Article
Engineering, Electrical & Electronic
Jian-Qiang Lin, Shing-Chow Chan, Ho-Chun Wu
Summary: This article proposes a robust recursive ESPRIT algorithm with variable forgetting factor (VFF) and variable regularization (VR) for online frequencies/harmonics estimation. The algorithm is based on the projection approximation subspace tracking method and incorporates the locally optimal FF (LOFF) scheme. It reduces estimation variance in signal fading scenarios with the use of the VR scheme and employs a robust statistics-based M-estimate objective function to suppress the adverse effect of impulsive noise.
IEEE TRANSACTIONS ON INSTRUMENTATION AND MEASUREMENT
(2022)
Article
Mathematics, Applied
Changbao Deng, Weinuo Jiang, Shihong Wang
Summary: This paper introduces a random resetting method for discrete-time dynamic networks, investigates the statistical characteristics of the method with numerical simulations, and evaluates the method for limited data, weak coupling, and multiple-attractor systems.
Article
Mathematics
Guido Gentile, Faenia Vaia
Summary: In the presence of dissipation, the study focuses on quasi-periodically systems and the existence of response solutions with the same frequency vector as the forcing term. By analyzing non-simple zeroes and confining to two-dimensional frequency vectors for dealing with small divisors, the research shows that response solutions exist given certain conditions on the parameter and frequency vector. The existence of response solutions in a set with holes is obtained, with the requirement of non-resonance condition on the frequency for a connected set.
JOURNAL OF DIFFERENTIAL EQUATIONS
(2021)
Article
Neurosciences
Almudena Capilla, Lydia Arana, Marta Garcia-Huescar, Maria Melcon, Joachim Gross, Pablo Campo
Summary: This study created an atlas of the natural frequencies of the resting human brain at the voxel level using a multivariate data-driven approach. The results revealed a region-specific organization of intrinsic oscillatory activity and provided empirical confirmation of canonical frequency bands.
Article
Materials Science, Multidisciplinary
Xuhan Lv, Yaodong Yang, Dongcai Zhang, Ziliang Wang, Kailin Li, Weifeng Rao
Summary: To solve the mismatch between external excitation and the resonant frequency of a harvester, a ratchet spring structure is designed to capture waves from a wide range of frequencies (1-19.7 Hz) and convert them into the resonant frequency of cantilevers. This energy harvester effectively alleviates hazardous problems caused by sudden changes in wave frequency and shows promising potential to power marine sensors, with a good power output (19.44 mW). Advanced design tools, including artificial neural network algorithms, were used for parameter optimization.
MATERIALS TODAY COMMUNICATIONS
(2023)
Article
Astronomy & Astrophysics
Sajad Abbar
Summary: In this study, a machine learning approach is used for the first time to detect fast flavor conversions in dense neutrino gases. The ML algorithms achieve an accuracy of about 95%, which is close to the Bayes error rate of the problem. This approach provides an unprecedented opportunity to evaluate such conversions in simulations on the fly.
Article
Engineering, Electrical & Electronic
David Boteler, Charalambos A. Charalambous, Kenneth Lax
Summary: Electromagnetic interference from AC sources has been a concern for pipelines and railways. Calculations of induced voltages have been developed, but some standards neglect the phase relationship of currents and the influence on induced currents in the earth. This paper introduces a revised complex image method that accurately calculates induced emf in nearby conductors.
IEEE TRANSACTIONS ON POWER DELIVERY
(2022)
Article
Optics
Martin Gaerttner, Tobias Haas, Johannes Noll
Summary: The study demonstrates the universality of continuous variable entanglement criteria based on the Husimi Q distribution through a theorem by Lieb and Solovej, showing their general nature and optimization potential in continuous majorization theory. The derived criteria are compared with marginal-based criteria and the strength of the phase-space approach is highlighted for detecting entanglement in certain example states. Furthermore, optimization prospects are explored in experimentally relevant scenarios with sparse data, leading to clear improvements in detecting a wider range of states and enhancing the signal-to-noise ratio.
Article
Energy & Fuels
Tomasz Tarasiuk, Piotr Jankowski, Viknash Shagar, Andrzej Pilat, Mariusz Gorniak, Jaroslaw Nowak
Summary: The proposed paper aims to compare the behavior of supply voltage registered onboard three vessels equipped with high power converters during normal operation, and analyze and discuss the characteristics of irregular fluctuations and oscillatory behavior.
FRONTIERS IN ENERGY RESEARCH
(2021)
Article
Multidisciplinary Sciences
Elie Rassi, Yi Zhang, German Mendoza, Juan Carlos Mendez, Hugo Merchant, Saskia Haegens
Summary: Based on previous research on content-specific beta synchronization in working memory and decision making, this study hypothesized that beta oscillations support cortical representations by mediating neural ensemble formation. The researchers found that beta activity in monkey dorsolateral prefrontal cortex (dlPFC) and pre-supplementary motor area (preSMA) reflects the content of a stimulus in relation to the task context, regardless of its objective properties. They also discovered two distinct beta-band frequencies consistently associated with different relative categories, which predicted the animals' responses.
NATURE COMMUNICATIONS
(2023)
Article
Computer Science, Information Systems
Boris A. Avdeev, Aleksei V. Vyngra, Sergei G. Chernyi, Anton A. Zhilenkov, Sergey S. Sokolov
Summary: This paper addresses the problem of isolating, evaluating, and eliminating interharmonics of current in the operation of an asynchronous electric motor under variable periodic load. Through simulation modeling and experimental studies, it proposes the use of active harmonic filters to reduce interharmonics in devices operating with variable periodic load. The results justify the effectiveness of this approach in suppressing interharmonics in electric drive circuits.
Article
Mathematics
Hongwei Huang, Heping Wang
Summary: This paper proves the analogues of important inequalities such as Bernstein, Kolmogorov, Marcinkiewicz-Zygmund, Nikolskii, etc. in Lebesgue spaces with variable exponents on the sphere.
JOURNAL OF GEOMETRIC ANALYSIS
(2022)
Article
Astronomy & Astrophysics
Daria Shukhobodskaia, Alexander A. Shukhobodskiy, Robert Erdelyi
Summary: This study explores oscillations in a thin straight expanding magnetic flux tube, finding that cooling increases amplitude and is related to the expansion factor. Higher wave numbers lead to localized oscillations closer to the boundary.
ASTRONOMY & ASTROPHYSICS
(2021)
Article
Astronomy & Astrophysics
Dixeena Lopez, Shubhanshu Tiwari, Marco Drago, David Keitel, Claudia Lazzaro, Giovanni Andrea Prodi
Summary: This study explores the prospect of finding glitching neutron stars using a generic all-sky search for short-duration gravitational wave transients. We find that the detectable glitch size for the fifth observing run with pulsars similar to the Vela pulsar is around 10(-5) Hz, and present the prospects of localizing the direction in the sky of these sources with gravitational waves alone.
Article
Entomology
Jonathan A. Walter, Lawrence W. Sheppard, P. Dilip Venugopal, Daniel C. Reuman, Galen Dively, John F. Tooker, Derek M. Johnson
ECOLOGICAL ENTOMOLOGY
(2020)
Article
Biochemical Research Methods
Yunus A. Abdulhameed, Peter V. E. McClintock, Aneta Stefanovska
JOURNAL OF BIOPHOTONICS
(2020)
Article
Neurosciences
Gemma Lancaster, Tadej Debevec, Gregoire P. Millet, Mathias Poussel, Sarah J. Willis, Minca Mramor, Katja Goricar, Damjan Osredkar, Vita Dolzan, Aneta Stefanovska
JOURNAL OF PHYSIOLOGY-LONDON
(2020)
Article
Ecology
Lawrence W. Sheppard, Brandon Mechtley, Jonathan A. Walter, Daniel C. Reuman
ECOLOGY AND EVOLUTION
(2020)
Article
Ecology
Lei Zhao, Shaopeng Wang, Lauren M. Hallett, Andrew L. Rypel, Lawrence W. Sheppard, Max C. N. Castorani, Lauren G. Shoemaker, Kathryn L. Cottingham, Katharine Suding, Daniel C. Reuman
Article
Ecology
Shyamolina Ghosh, Lawrence W. Sheppard, Daniel C. Reuman
Article
Plant Sciences
Jonathan A. Walter, Lauren M. Hallett, Lawrence W. Sheppard, Thomas L. Anderson, Lei Zhao, Richard J. Hobbs, Katharine N. Suding, Daniel C. Reuman
Summary: Through studying micro-scale synchrony and geographies of synchrony within a serpentine grassland plant community, it was found that species populations exhibited a geography of synchrony even over distances up to 30 meters. Factors such as gopher disturbance and dispersal limitation played a major role in shaping the spatial structure of synchrony, while precipitation was a significant driver of temporal dynamics at both site and community levels.
JOURNAL OF ECOLOGY
(2021)
Article
Ecology
Thomas L. Anderson, Lawrence W. Sheppard, Jonathan A. Walter, Robert E. Rolley, Daniel C. Reuman
Summary: Population cycles and spatial synchrony are fundamentally linked, with the ability of synchrony to cause population cycles demonstrated in this study. Specific environmental effects on certain timescales synchronize local population dynamics, leading to significant population cycles over large areas in white-tailed deer. This mechanism highlights the impact of synchrony on both wildlife populations and human systems, with potential implications for changes in population cycles due to alterations in synchrony drivers such as climate change.
Article
Mathematics, Applied
Julian Newman, Aleksandra Pidde, Aneta Stefanovska
Summary: Bispectral analysis is an effective tool for investigating interactions between oscillations, and has been adapted to the continuous wavelet transform for time-evolving analysis of open systems. By providing suitable normalizations of the wavelet bispectrum formula, it can be treated as a density to be integrated, overcoming limitations of qualitative interpretation. The improved quantitative power of this definition is illustrated through numerical and experimental data, showing its match with traditional bispectra in the limit of infinite frequency resolution.
APPLIED AND COMPUTATIONAL HARMONIC ANALYSIS
(2021)
Article
Physiology
Joe Rowland Adams, Aneta Stefanovska
Summary: Networks of oscillating processes are common in living systems, especially in the energy metabolism of individual cells. Introducing oscillating networks can increase the synchronization of models and help processes resist external disturbances. Compared to traditional models, models with fewer parameters and greater flexibility can produce oscillating outputs comparable to experimental measurements.
FRONTIERS IN PHYSIOLOGY
(2021)
Article
Ecology
Mingyu Luo, Daniel C. Reuman, Lauren M. Hallett, Lauren Shoemaker, Lei Zhao, Max C. N. Castorani, Joan C. Dudney, Laureano A. Gherardi, Andrew L. Rypel, Lawrence W. Sheppard, Jonathan A. Walter, Shaopeng Wang
Summary: The study investigates how dispersal affects population variability and spatial synchrony at different timescales, showing that the effects of dispersal on populations are opposite between short and long timescales. The impact of dispersal differs for populations with different recovery mechanisms, with implications for empirical studies.
Article
Mathematics, Applied
J. Newman, M. Lucas, A. Stefanovska
Summary: This study introduces a new mathematical framework for analyzing the qualitative stability of finite-time processes under slow external influences, through a slow-fast formalism and consideration of stability in the singular limit. It provides stability definitions for one-dimensional phase dynamics analogous to classical infinite-time definitions, formalizing and generalizing a phase-stabilization phenomenon previously described in physics literature.
Article
Physics, Multidisciplinary
Samuel J. K. Barnes, Aneta Stefanovska
Summary: New physics-based approaches are helping us better understand cellular functions, providing information on predictable stability, and replicating measured data. These methods are likely to improve our understanding of how diseases affect cells and pave the way for new treatment and diagnostic methods.
CONTEMPORARY PHYSICS
(2021)
Article
Biology
Megan Morris, Shin Yamazaki, Aneta Stefanovska
Summary: Circadian rhythms are internal processes in living organisms that repeat approximately every 24 hours and are synchronized to the light-dark cycle. This study investigated the rhythmic components and phase coupling in mice with a disabled circadian clock. The findings provide insights into the functional significance of different oscillators and their coupling. Understanding circadian rhythms is crucial for studying diseases and mood disorders.
JOURNAL OF BIOLOGICAL RHYTHMS
(2022)
Article
Ecology
Shyamolina Ghosh, Lawrence W. Sheppard, Philip C. Reid, Daniel Reuman
ECOLOGY AND EVOLUTION
(2020)