Article
Water Resources
Hezi Yizhaq, Yosef Ashkenazy
Summary: Vegetation and biocrust are crucial for the stability and mobility of sand dunes, and their interaction can lead to bistability, temporal oscillations, and hysteresis. A study of a 2D mathematical model showed that the intrinsic dynamics between vegetation and biocrust can generate spatial heterogeneity and complexity.
JOURNAL OF HYDROLOGY AND HYDROMECHANICS
(2022)
Article
Chemistry, Physical
Brigitta Duzs, Istvan Szalai
Summary: Operating natural or artificial chemical systems requires nonequilibrium conditions, which can be achieved by open reaction-diffusion systems like hydrogels. By separating two reactants in two channels in a hydrogel, a bipolar antagonistic diffusion field is created, allowing for spatial separation of reaction intermediates.
PHYSICAL CHEMISTRY CHEMICAL PHYSICS
(2022)
Article
Mathematics, Interdisciplinary Applications
A. K. Misra, Akash Yadav
Summary: Given the growth of the human population and the decrease in cultivable land, sustainable crop production has become increasingly important. This research proposes a nonlinear mathematical model to control insect populations and increase crop production through the use of insecticide spraying. The model takes into account both the density of insects and the loss in crop production caused by their presence. The study also identifies the range of insecticide spraying rates that lead to bistability behavior in the model, as well as the threshold value at which the system stabilizes to a higher crop production equilibrium. Various bifurcations, including transcritical, saddle-node, Hopf, and Bogdanov-Takens bifurcations, are demonstrated in the model. Extensive numerical simulations are conducted to validate the analytical findings.
INTERNATIONAL JOURNAL OF BIFURCATION AND CHAOS
(2023)
Article
Soil Science
Haneen Omari, Nicole Pietrasiak, Scott Ferrenberg, Michele K. Nishiguchi
Summary: The composition and dynamics of microbial and microfaunal communities in biocrusts in the northern Chihuahuan Desert are influenced by biocrust type, season, and surrounding vegetation. Microbial communities are more affected by biocrust type, while microfaunal communities are more influenced by sampling season. Seasonal changes in biocrust chemical properties also play a role in shaping microbial communities.
Article
Geosciences, Multidisciplinary
Katerina Kombiadou, Susana Costas, Dano Roelvink
Summary: Process-based morphodynamic models can help understand the responses and evolutionary patterns of coastal dunes to disturbances. The Duna model, a simplified 1D morphodynamic model, is used to assess the influence of dune morphology on sand transfer and deposition. The model shows good performance in reproducing wind flow and topographic change along the dune profiles. The results indicate that dune height and slope play a significant role in wind speed and sand accumulation, and different evolutionary patterns can occur depending on vegetation density and beach width.
JOURNAL OF GEOPHYSICAL RESEARCH-EARTH SURFACE
(2023)
Article
Multidisciplinary Sciences
Joaquin Moreno, Sergio Asensio, Miguel Berdugo, Beatriz Gozalo, Victoria Ochoa, David S. Pescador, Blas M. Benito, Fernando T. Maestre
Summary: Drylands cover approximately 41% of the terrestrial surface and soil moisture plays a crucial role in determining hydrological processes and the activity and performance of organisms in these ecosystems. The MOISCRUST dataset, a long-term soil moisture dataset from a Mediterranean semiarid dryland, provides valuable insights into the dynamics of soil water and its impacts on both vascular plants and biocrusts, contributing to a better understanding of dryland ecosystems and their responses to climate change.
Article
Biology
Lucie Plazen, Anmar Khadra
Summary: Mesenchymal cell motility is regulated by Rac and Rho, with Rac promoting cellular polarization and Rho inhibiting Rac activation. Mathematical modeling has shown that bistability and wave-pinning play a role in cellular polarity. A simplified 3V ODE model and a 4V PDE model with diffusion were developed to study the dynamics of Rac, Rho, and paxillin. The models exhibit relaxation oscillations and mixed-mode oscillations, which suggest their potential relevance in mesenchymal cell motility.
JOURNAL OF THEORETICAL BIOLOGY
(2023)
Article
Biochemical Research Methods
Irene Zorzan, Simone Del Favero, Alberto Giaretta, Riccardo Manganelli, Barbara Di Camillo, Luca Schenato
Summary: In this work, a mathematical model of the SigE stress response network is developed, incorporating interactions not considered in current literature. Through detailed analytical computations, accurate approximations of the system's nullclines are provided to determine the number of equilibrium points efficiently. The study highlights the crucial role of fine control on RseA concentration for bistability in the system.
BMC BIOINFORMATICS
(2021)
Article
Physics, Multidisciplinary
Yu-Hui Chen, Sebastian P. Horvath, Jevon J. Longdell, Xiangdong Zhang
Summary: A new dynamical phase of intrinsic optical instability was experimentally revealed, where the transmission through the sample became unstable under intense laser inputs and transient net gain was observed if the light passed the sample twice. The phase transition between states in and out of a dynamical equilibrium was induced by dipole-dipole interactions between nearby erbium ions.
PHYSICAL REVIEW LETTERS
(2021)
Article
Mathematics, Applied
R. Herrero, J. Farjas, F. Pi, G. Orriols
Summary: This paper presents a way to penetrate the space of dynamical systems by nonlinearly mixing a large number of oscillation modes, resulting in complex time evolutions. The design is based on the occurrence of Hopf bifurcations in a set of fixed points of ordinary differential equations, where nonlinearities are introduced through functions of a linear combination of system variables. Numerical simulations demonstrate the rich and unknown dynamical behaviors of the designed systems. The paper focuses on the oscillatory mixing effects on periodic orbits, showing the enrichment of harmonic oscillations without bifurcations.
Review
Biology
Gui-Quan Sun, Li Li, Jing Li, Chen Liu, Yong-Ping Wu, Shupeng Gao, Zhen Wang, Guo-Lin Feng
Summary: This review systematically reveals the spatial and temporal impacts of climate change on vegetation dynamics through dynamical modeling and data analysis. It provides a foundation for understanding the coupling effect of climate change on ecosystems.
PHYSICS OF LIFE REVIEWS
(2022)
Article
Chemistry, Multidisciplinary
Hongzhang Wang, Zhenfang Cheng, Ling Yuan, Lin Ren, Changwei Pan, Irving R. Epstein, Qingyu Gao
Summary: In this study, the role of fast and slow inhibitors in oscillatory reaction networks was experimentally and theoretically analyzed. It was found that these inhibitors generate time delays and result in different oscillation patterns. This understanding is significant for the study of chemical and biochemical rhythms and the design of similar behaviors.
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
(2023)
Article
Endocrinology & Metabolism
N. Bruce, I. -A. Wei, W. Leng, Y. Oh, Y. -C. Chiu, M. G. Roper, R. Bertram
Summary: Insulin secretion from islets of Langerhans is coordinated through negative feedback, even with time delays. A microfluidic system was used to monitor Ca2+ levels in a small population of islets, revealing that islet synchronization occurs even with delays in negative feedback. Additionally, a slower oscillation mode was observed during delayed feedback, where faster oscillations were grouped into episodes.
AMERICAN JOURNAL OF PHYSIOLOGY-ENDOCRINOLOGY AND METABOLISM
(2022)
Article
Cell Biology
Bertrand de Prelle, Pascale Lybaert, David Gall
Summary: Mammalian spermatozoa need a prolonged exposure to the alkaline medium of the female genital tract to become capable of fertilizing the oocyte. This process, called capacitation, involves ionic fluxes across the sperm membrane and the activation of specific transmembrane proteins. Here, we developed a mathematical model to study the positive feedback loop between the SLO3 potassium channel and the sNHE sodium-proton exchanger in mouse epididymal sperm during capacitation. Our model explains the switch between the uncapacitated and capacitated states and predicts the existence of a bistable behavior. Additionally, our model suggests that inhibiting the SLO3 channel can effectively prevent capacitation.
FRONTIERS IN CELL AND DEVELOPMENTAL BIOLOGY
(2022)
Article
Biochemical Research Methods
Eran Agmon, Ryan K. Spangler, Christopher J. Skalnik, William Poole, Shayn M. Peirce, Jerry H. Morrison, Markus W. Covert
Summary: Vivarium is a software tool for building integrative multiscale models, providing an interface that allows computational biologists to easily define mechanistic models and combine them as an integrated multiscale model. It streamlines the integrative modeling effort by making individual models into modules that can be wired together and run with Vivarium's discrete-event simulation engine. This tool has been demonstrated to successfully build composite models that combine various modeling frameworks, and it has the potential to support future efforts in integrating more types of models at different biological scales.
Article
Education, Scientific Disciplines
David Agmon, Hezi Yizhaq
Summary: This paper demonstrates the convergence of a discrete brachistochrone into a continuous brachistochrone, known as a cycloid, as the number of segments approaches infinity. The proofs are based on the characteristics of the discrete brachistochrone, showing that at any point, the sliding bead has the same velocity and curvature radius on both paths. The acceleration magnitude along the cycloid is constant and equal to g, with the acceleration vector directed towards the center of the wheel.
EUROPEAN JOURNAL OF PHYSICS
(2021)
Article
Plant Sciences
Stephan Getzin, Todd E. Erickson, Hezi Yizhaq, Miriam Munoz-Rojas, Andreas Huth, Kerstin Wiegand
Summary: The study in spinifex-grassland ecosystem of Western Australia demonstrates that the fairy circles (FCs) pattern influences the vitality of grass, with high-vitality grasses being more associated with FCs. The feedback exhibited by grass at different scales not only indicates facilitation or competition, but also supports the infiltration feedback as proposed in theoretical models. These findings further validate the importance of scale-dependent feedbacks in explaining the emergent grassland pattern.
JOURNAL OF ECOLOGY
(2021)
Article
Geochemistry & Geophysics
Yongwen Zhang, Yosef Ashkenazy, Shlomo Havlin
Summary: This study focuses on the asymmetry of interevent time series in earthquake catalogs, finding that there is a significant crossover from high to low asymmetry as lag index increases. Different earthquake triggering processes are associated with the two distinct regimes of asymmetry, and a new generalized ETAS model better reproduces the observed asymmetry compared to the standard ETAS model.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Ecology
Stephan Getzin, Christian Loens, Hezi Yizhaq, Todd E. Erickson, Miriam Munoz-Rojas, Andreas Huth, Kerstin Wiegand
Summary: The study found that small gaps consistently appeared about 5 meters away from the fairy circles, which are known as the most water-depleted locations in the grassland. The fairy circles were rounder than the small gaps, indicating their function as an extra source of water for the surrounding matrix vegetation. Trees and shrubs had spatial patterns unrelated to fairy circles, likely due to their water uptake in deeper sub-soil layers.
Article
Multidisciplinary Sciences
Yosef Ashkenazy, Eli Tziperman
Summary: The deep ocean of Europa, covered by a thick icy shell, has the potential to harbor extraterrestrial life. This study added critical elements to previous ocean dynamics research, revealing that the ocean is weakly stratified and dominated by salinity variations, exhibiting strong transient convection and eddies.
NATURE COMMUNICATIONS
(2021)
Article
Mathematics, Applied
H. Yizhaq, Y. Ashkenazy
Summary: This article proposes a model to study the spatiotemporal dynamics of the coupling between biocrust and vegetation cover on sand dunes. The model demonstrates that the front connecting the dominance of biocrust and vegetation is mainly propagated by wind advection. In the presence of low wind drift potential values, spatially oscillatory domains develop as the front advances downwind, while higher wind drift potential values result in more complex dynamics with irregular spatial patterns.
Editorial Material
Astronomy & Astrophysics
Hezi Yizhaq, Simone Silvestro
Summary: A unified theory of particle transport by wind can explain the aeolian features, such as dunes, observed on rocky bodies across the Solar System with atmospheres.
Article
Geochemistry & Geophysics
Yosef Ashkenazy, Hezi Yizhaq
Summary: In this study, the researchers analyze the global pattern of surface winds using ERA5 reanalysis data. They find that the maximum wind speed occurs during midday over land and especially over sand dune regions, while over the ocean, the wind peaks at night. The weakening of winds over land at night is attributed to nocturnal cooling, which decouples upper atmospheric levels from the surface. Comparisons with meteorological stations show that ERA5 underestimates real winds but exhibits similar temporal patterns.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)
Article
Geosciences, Multidisciplinary
Hezi Yizhaq, Jasper F. Kok, Simone Silvestro, Lior Saban, Itzhak Katra
Summary: Ripples made from unimodal fine sands on Mars can be much larger than those on Earth, with a longer time scale for their formation.
Article
Environmental Studies
Eli Zaady, Ilan Stavi, Vladislav Dubinin, Nina Kamennaya, Hiam Abu-Glion, Shimshon Shuker, Hezi Yizhaq
Summary: This study evaluates the effects of geodiversity on the biogeochemical functions of biocrusts and finds that higher geodiversity in slopes leads to higher soil moisture content and concentrations of ammonium and labile organic carbon in biocrusts, enhancing the survival of plants under long-term drought conditions.
Article
Geosciences, Multidisciplinary
Yosef Ashkenazy, Eli Tziperman, Francis Nimmo
Summary: It is suggested that the ice shell of Jupiter's moon Europa can drift non-synchronously due to tidal torques, but our study argues that torques from the underlying ocean are also influential and can cause non-synchronous rotation. We developed an ice shell rotation model considering ocean stress and viscoelastic deformation of the ice shell. Our results indicate sluggish ice shell convection and the possibility of negligible drift or oscillatory drift. Future spacecraft observations can test these predictions and provide insights into the properties of the ice shell and underlying ocean.
Article
Plant Sciences
Hezi Yizhaq, Ilan Stavi
Summary: In drylands, clonal plants can form ring patterns in sandy environments, which expand gradually and leave bare soil in the center. The formation of these rings is driven by the infiltration feedback, which is enhanced by microtopography. The S. obtusa rings in the north-eastern Negev of Israel are formed on small mounds due to continuous deposition of sand and dust and have higher water infiltrability compared to the inter-ring spaces. During heavy rainstorms, runoff partially percolates in the rings' periphery, promoting radial expansion and increasing water availability for the S. obtusa plants.
Article
Environmental Studies
Hezi Yizhaq, Abdel Rahman Mohammad Said Al-Tawaha, Ilan Stavi
Summary: This study presents the first report of vegetation rings in the geophyte species Urginea maritima and found that soil-water content and organic carbon content were significantly higher in the rings' periphery compared to the center and matrix. Possible mechanisms for ring formation include soil-water uptake mechanism and plant-soil negative feedback. Multiple mechanisms may simultaneously affect the formation of U. maritima rings.
