Article
Optics
A. Goffin, A. Tartaro, H. M. Milchberg
Summary: We present a quasi-continuously operating air waveguide created through high-repetition-rate patterned filamentation of femtosecond laser pulses. By exceeding the air thermal relaxation rate, we achieve near-continuous guiding of a CW probe beam with enhanced efficiency.
Article
Mathematics, Applied
Elisenda Feliu, Christian Lax, Sebastian Walcher, Carsten Wiuf
Summary: This paper provides a thorough discussion on the quasi-steady state (QSS) reduction method and its relation to singular perturbation reduction. It focuses on the case where the right-hand side of the differential equation is linear in the variables to be eliminated. Necessary and sufficient conditions for the existence of singular perturbation reduction, in accordance with QSS reduction, are given. The results are applied to chemical reaction networks, with easy-to-check graphical conditions provided for selecting applicable parameter values.
SIAM JOURNAL ON APPLIED DYNAMICAL SYSTEMS
(2022)
Article
Engineering, Mechanical
Michail L. Pivovarov
Summary: In this study, a quasi-linear Mathieu-type equation is analyzed using the averaging method near the main resonance. Different types of phase portraits are identified and steady-state solutions are found. The periodic solutions of the primary equation that correspond to the steady-state solutions of the averaged equation are determined, along with analytical expressions for the probabilities of dissipation-induced capture into feasible steady-state solutions.
NONLINEAR DYNAMICS
(2021)
Article
Energy & Fuels
Hongliang Luo, Feixiang Chang, Cheng Zhan, Keiya Nishida, Yoichi Ogata, Jin Zhang, Jing Yao, Xiangdong Kong, Jingyu Zhu
Summary: This study used a multiple droplets producer to observe the impingement of multiple droplets on the wall at different injection pressures. Experimental results show that droplet behaviors near the wall can be recorded at T-slicer = 40 mu m during the injection. Additionally, observations of coalescence phenomenon of secondary droplets and splashing crown structures occurrence provide further insights into droplet size and velocity changes near the wall.
Article
Mathematics, Applied
Jiangming Xiang, Xiaoqun Wang
Summary: This paper addresses the challenging problem of estimating American option sensitivities in financial engineering, proposing efficient QMC methods combined with dimension reduction techniques. Numerical experiments demonstrate that this approach can significantly reduce the variance of the estimators.
JOURNAL OF COMPUTATIONAL AND APPLIED MATHEMATICS
(2022)
Article
Chemistry, Multidisciplinary
Azimberdy Besya, Shodhan Rao
Summary: The focus of this study is on the approximation method and validity conditions of tQSSA for multiple substrate reactions. By introducing a linearization method, an analytical solution for tQSSA equations of multiple substrate reactions is obtained, and the validity conditions of tQSSA are determined using the singular perturbation analysis method.
JOURNAL OF MATHEMATICAL CHEMISTRY
(2022)
Article
Multidisciplinary Sciences
Alejandro Stawsky, Harsh Vashistha, Hanna Salman, Naama Brenner
Summary: In balanced exponential growth, some variables in bacterial single-cell dynamics are sloppily regulated while others define stiff combinations with robust set points. Sloppiness is primarily driven by the environment, while set points of stiff combinations span a wide range of values within the manifold.
Article
Chemistry, Multidisciplinary
Shu-Chuan Chu, Zhongjie Zhuang, Junbao Li, Jeng-Shyang Pan
Summary: The QUATRE algorithm generalizes the differential evolution algorithm to matrix form, introduces a binary version with two approaches, and proposes four families of transfer functions for binarization. Experimental results show the superiority of the proposed methods and their effectiveness in dimensionality reduction for hyperspectral images.
APPLIED SCIENCES-BASEL
(2021)
Article
Mathematics
Vasiliki Bitsouni, Nikolaos Gialelis, Ioannis G. Stratis
Summary: This study examines the quasi-steady-state assumption in the fundamental mathematical model of enzymatic reactions from a purely quantitative perspective. The study introduces a simple yet generic scaling algorithm for the problem, quantitatively defines the two essential parts of the assumption (standard and reverse), and comments on the dispensable third part (total) that is commonly adopted.
Article
Biochemistry & Molecular Biology
Kevin P. Mulder, Lucia Alarcon-Rios, Alfredo G. Nicieza, Robert C. Fleischer, Rayna C. Bell, Guillermo Velo-Anton
Summary: Viviparity, the ability to bear live offspring, has evolved independently in all three amphibian orders, with at least five independent transitions identified among and within species. These transitions occurred at different evolutionary timescales, ranging from the Pliocene to the Holocene. The study also confirms introgression between species and highlights the need for taxonomic revisions in the genus for future studies on the genetic architecture of this specialized reproductive mode.
MOLECULAR PHYLOGENETICS AND EVOLUTION
(2022)
Article
Biology
Justin Eilertsen, Santiago Schnell, Sebastian Walcher
Summary: In this study, we present a simplified model for the irreversible Michaelis-Menten reaction mechanism under quasi-steady-state conditions. We complement existing research by identifying local conditions that prevent quasi-steady-state reductions, both in the classical and broader sense. Furthermore, we discuss parameter regions where no quasi-steady-state reduction is applicable and show that these regions are small in a well defined sense. Additionally, we provide local conditions for the accuracy of standard or total quasi-steady-state.
MATHEMATICAL BIOSCIENCES
(2022)
Article
Computer Science, Artificial Intelligence
Jie Zhong, Bowen Li, Yang Liu, Jianquan Lu, Weihua Gui
Summary: This article examines the steady-state design of large-dimensional Boolean networks via model reduction and pinning control, reducing computational complexity significantly. The proposed method is demonstrated on two specific networks, showing a substantial reduction in redundant states.
IEEE TRANSACTIONS ON NEURAL NETWORKS AND LEARNING SYSTEMS
(2021)
Article
Computer Science, Information Systems
Jonte Dancker, Martin Wolter
Summary: This paper presents a joined quasi-steady-state power flow calculation method for integrated energy systems, which considers the dynamic behavior of the district heating system, gas system, and the impact of network storage. It demonstrates the significant effect of network storage on the operation of an integrated energy system and enhances existing steady-state power flow calculation methods.
Article
Chemistry, Physical
Lei Sheng, Zhendong Zhang, Lin Su, Hengyun Zhang, Hua Zhang, Yidong Fang, Kang Li, Wen Ye
Summary: This study proposes a new method to measure the thermophysical parameters of cylindrical lithium ion batteries, taking into account heat loss, and validates its effectiveness through experimentation. The results show that both the thermal conductivity and specific heat of the cells increase linearly with operating temperature, with temperature having a greater impact on specific heat than on thermal conductivity.
JOURNAL OF POWER SOURCES
(2021)
Article
Physics, Mathematical
Xinyu Cheng, Hyunju Kwon, Dong Li
Summary: We demonstrate the existence of nontrivial stationary weak solutions to the surface quasi-geostrophic equations on the two dimensional periodic torus.
COMMUNICATIONS IN MATHEMATICAL PHYSICS
(2021)
Article
Neurosciences
Jonathan D. Victor, Sebastian D. Boie, Erin G. Connor, John P. Crimaldi, G. Bard Ermentrout, Katherine Nagel
JOURNAL OF NEUROSCIENCE
(2019)
Article
Mathematics, Applied
Samuel Jelbart, Martin Wechselberger
Article
Mathematics, Applied
Ian Lizarraga, Robert Marangell, Martin Wechselberger
JOURNAL OF NONLINEAR SCIENCE
(2020)
Article
Mathematics
Samuel Jelbart, Kristian Uldall Kristiansen, Martin Wechselberger
Summary: We study the transition of smooth systems to piecewise-smooth systems with a boundary-focus bifurcation as epsilon -> 0, and identify different bifurcation structures. We uncover the evolution characteristics of cycles associated with BF bifurcations in the smooth system, and prove the existence of a family of stable limit cycles.
JOURNAL OF DIFFERENTIAL EQUATIONS
(2021)
Article
Mathematics, Applied
S. Jelbart, K. U. Kristiansen, P. Szmolyan, M. Wechselberger
Summary: This paper investigates two prototypical singularly perturbed oscillators with exponential nonlinearities, normalizing both systems to a piecewise smooth system in the limit is an element of -> 0, showing exponential convergence due to the nonlinearities studied. By extending spatial dimensions, degeneracies caused by exponentially small terms are tackled for the second model system, with (unique) limit cycles proven to exist for both systems by perturbing away from singular cycles with desirable hyperbolicity properties.
JOURNAL OF DYNAMICS AND DIFFERENTIAL EQUATIONS
(2022)
Article
Mathematics, Applied
S. Jelbart, K. U. Kristiansen, M. Wechselberger
Summary: This work completes a classification of codimension-1 singularly perturbed boundary equilibria bifurcation (BEB) in the plane, utilizing tools from PWS theory, geometric singular perturbation theory, and the method of geometric desingularization known as blow-up. Local normal forms for generating all 12 singularly perturbed BEBs are derived, and the unfolding in each case is described. Detailed quantitative results on various bifurcations involved in the unfoldings and classification are presented, including saddle-node, Andronov-Hopf, homoclinic, and codimension-2 Bogdanov-Takens bifurcations.
Article
Mathematics, Applied
Ian Lizarraga, Bob Rink, Martin Wechselberger
Summary: The novel method presented in this study computes slow manifolds and fast fibre bundles in geometric singular perturbation problems with high degrees of accuracy, making it suitable for systems with multiple timescales. This top-down approach highlights the emergence of hidden timescales and can uncover surprising multiple timescale structures. It has been successfully applied to various reaction network problems.
Article
Mathematics, Applied
Yifei Li, Peter van Heijster, Matthew J. Simpson, Martin Wechselberger
Summary: Reaction-diffusion equations (RDEs) are derived from lattice-based discrete models, with recent developments allowing for negative diffusion terms. Numerical simulations support shock-fronted travelling waves in RDEs with Allee effects. By embedding RDEs in a larger class of PDEs, the existence of shock-fronted travelling waves has been proven, with different embeddings leading to waves with varying properties.
PHYSICA D-NONLINEAR PHENOMENA
(2021)
Article
Astronomy & Astrophysics
Eric W. Hester, Geoffrey M. Vasil, Martin Wechselberger
Summary: This study investigates shocks in a thin isothermal black hole accretion flow and finds that the inner shock is always unstable while the outer shock is always stable. The growth/decay rates of perturbations depend on an effective potential and the incoming-outgoing flow difference at the shock location. A prescription of accretion regimes in terms of angular momentum and black hole radius is provided, with unstable outer shocks being implied in much of the parameter space when accounting for viscous angular momentum dissipation.
MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY
(2022)
Article
Mathematics, Applied
Samuel Jelbart, Nathan Pages, Vivien Kirk, James Sneyd, Martin Wechselberger
Summary: This article discusses ordinary differential equations (ODEs) used to model phenomena in chemistry, biology, and neuroscience, and presents a heuristic procedure for identifying small parameters in these ODE models. The procedure is applied to a model of intracellular calcium dynamics characterized by switching and multiple time-scale dynamics. Using geometric singular perturbation theory, the existence and uniqueness of stable relaxation oscillations with three distinct time scales are proven, and an estimate for the period of the oscillations is provided.
SIAM JOURNAL ON APPLIED DYNAMICAL SYSTEMS
(2022)
Article
Medical Informatics
Sebastian Daniel Boie, Lilian Jo Engelhardt, Nicolas Coenen, Niklas Giesa, Kerstin Rubarth, Mario Menk, Felix Balzer
Summary: This study evaluates the capability of different machine learning algorithms to predict patients' response to heparin treatment. The results show that a recurrent neural network that uses time series features has the highest performance in predicting aPTT after heparin treatment.
JMIR MEDICAL INFORMATICS
(2022)
Article
Mathematics, Applied
Nour Riman, Jonathan D. Victor, Sebastian D. Boie, Bard Ermentrout
Summary: The text discusses the importance of odor concentration for animals in localizing sources and following trails, analyzing a bilateral model and different types of odor landscapes with corresponding animal behaviors.
Article
Mathematics, Applied
Daniele Avitabile, Mathieu Desroches, Romain Veltz, Martin Wechselberger
SIAM JOURNAL ON MATHEMATICAL ANALYSIS
(2020)
Article
Mathematics, Applied
Kristen E. Harley, Peter van Heijster, Robert Marangell, Graeme J. Pettet, Timothy Roberts, Martin Wechselberger
SIAM JOURNAL ON APPLIED MATHEMATICS
(2020)
Article
Mathematics, Applied
Ian Lizarraga, Martin Wechselberger
SIAM JOURNAL ON APPLIED DYNAMICAL SYSTEMS
(2020)
Article
Biology
Iain Hunter, Raz Leib
Summary: Natural movement is related to health, but it is difficult to measure. Existing methods cannot capture the full range of natural movement. Comparing movement across different species helps identify common biomechanical and computational principles. Developing a system to quantify movement in freely moving animals in natural environments and relating it to life quality is crucial. This study proposes a theoretical framework based on movement ability and validates it in Drosophila.
JOURNAL OF THEORETICAL BIOLOGY
(2024)
Article
Biology
Andy Gardner
Summary: Fisher's geometric model is a useful tool for predicting key properties of Darwinian adaptation, and here it is applied to predict differences between the evolution of altruistic versus nonsocial phenotypes. The results suggest that the effect size maximizing probability of fixation is smaller in the context of altruism and larger in the context of nonsocial phenotypes, leading to lower overall probability of fixation for altruism and higher overall probability of fixation for nonsocial phenotypes.
JOURNAL OF THEORETICAL BIOLOGY
(2024)
Article
Biology
Thomas F. Pak, Joe Pitt-Francis, Ruth E. Baker
Summary: Cell competition is a process where cells interact in multicellular organisms to determine a winner or loser status, with loser cells being eliminated through programmed cell death. The winner cells then populate the tissue. The outcome of cell competition is context-dependent, as the same cell type can win or lose depending on the competing cell type. This paper proposes a mathematical framework to study the emergence of winner or loser status, highlighting the role of active cell death and identifying the factors that drive cell competition in a cell-based modeling context.
JOURNAL OF THEORETICAL BIOLOGY
(2024)
Article
Biology
Haruto Tomizuka, Yuuya Tachiki
Summary: Batesian mimicry is a strategy in which palatable prey species resemble unpalatable prey species to avoid predation. The evolution of this mimicry plays a crucial role in protecting the unpalatable species from extinction.
JOURNAL OF THEORETICAL BIOLOGY
(2024)
Article
Biology
Jason W. Olejarz, Martin A. Nowak
Summary: Gene drive technology shows potential for population control, but its release may have unpredictable consequences. The study suggests that the failure of suppression is a natural outcome, and there are complex dynamics among wild populations.
JOURNAL OF THEORETICAL BIOLOGY
(2024)
Article
Biology
Hamid Ravaee, Mohammad Hossein Manshaei, Mehran Safayani, Javad Salimi Sartakhti
Summary: Gene expression analysis is valuable for cancer classification and phenotype identification. IP3G, based on Generative Adversarial Networks, enhances gene expression data and discovers phenotypes in an unsupervised manner. By converting gene expression profiles into images and utilizing IP3G, new phenotype profiles can be generated, improving classification accuracy.
JOURNAL OF THEORETICAL BIOLOGY
(2024)
Article
Biology
Beatrix Rahnsch, Leila Taghizadeh
Summary: This study forecasts the evolution of the COVID-19 pandemic in Germany using a network-based inference method and compares it with other approaches. The results show that the network-inference based approach outperforms other methods in short-to mid-term predictions, even with limited information about the new disease. Furthermore, predictions based on the estimation of the reproduction number in Germany can yield more reliable results with increasing data availability, but still cannot surpass the network-inference based algorithm.
JOURNAL OF THEORETICAL BIOLOGY
(2024)
Article
Biology
Rongsheng Huang, Qiaojun Situ, Jinzhi Lei
Summary: Maintaining tissue homeostasis requires appropriate regulation of stem cell differentiation. Random inheritance of epigenetic states plays a pivotal role in stem cell differentiation. This computational model provides valuable insights into the intricate mechanism governing stem cell differentiation and cell reprogramming, offering a promising path for enhancing the field of regenerative medicine.
JOURNAL OF THEORETICAL BIOLOGY
(2024)
Article
Biology
Patrick Vincent N. Lubenia, Eduardo R. Mendoza, Angelyn R. Lao
Summary: This study compares insulin signaling in healthy and type 2 diabetes states using reaction network analysis. The results show similarities and differences between the two conditions, providing insights into the mechanisms of insulin resistance, including the involvement of other complexes, less restrictive interplay between species, and loss of concentration robustness in GLUT4.
JOURNAL OF THEORETICAL BIOLOGY
(2024)
Article
Biology
Nuverah Mohsin, Heiko Enderling, Renee Brady-Nicholls, Mohammad U. Zahid
Summary: Mathematical modeling is crucial in understanding radiobiology and designing treatment approaches in radiotherapy for cancer. This study compares three tumor volume dynamics models and analyzes the implications of model selection. A new metric, the point of maximum reduction of tumor volume (MRV), is introduced to quantify the impact of radiotherapy. The results emphasize the importance of caution in selecting models of response to radiotherapy due to the artifacts imposed by each model.
JOURNAL OF THEORETICAL BIOLOGY
(2024)
Article
Biology
Armindo Salvador
Summary: Michael Savageau's Biochemical Systems Analysis papers have had a significant impact on Systems Biology, generating core concepts and tools. This article provides a brief summary of these papers and discusses the most relevant developments in Biochemical Systems Theory since their publication.
JOURNAL OF THEORETICAL BIOLOGY
(2024)