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The existence of power-law distributions is only a first requirement in the validation of the critical behavior of a system. Long-range spatio-temporal correlations are fundamental for the spontaneous neuronal activity to be the expression…

Statistical Mechanics · Physics 2018-11-27 Fabrizio Lombardi , Hans J. Herrmann , L. de Arcangelis

Microorganisms self-organize in very large communities exhibiting complex fluctuations. Despite recent advances, still the mechanism by which these systems are able to exhibit large variability at the one hand and dynamical robustness on…

Populations and Evolution · Quantitative Biology 2022-06-27 Nahuel Zamponi , Tomas S. Grigera , Ewa Gudowska-Nowak , Dante R. Chialvo

The ratio of two densities provides a direct characterization of their differences. We consider the two-sample comparison problem by estimating this ratio given i.i.d. observations from two distributions. To this end, we propose additive…

Methodology · Statistics 2026-04-23 Naoki Awaya , Yuliang Xu , Li Ma

Dryland ecosystems commonly exhibit periodic bands of vegetation, thought to form due to competition between individual plants for heterogeneously distributed water. In this paper, we develop a Fourier method for locally identifying the…

Pattern Formation and Solitons · Physics 2014-03-05 G. G. Penny , K. E. Daniels , S. E. Thompson

Recent investigations have provided important insights into the complex structure and dynamics of collectively moving flocks of living organisms. Two intriguing observations are, scale-free correlations in the velocity fluctuations, in the…

Biological Physics · Physics 2022-03-22 Kunal Bhattacharya , Abhijit Chakraborty

We study the spatial patterns formed by a system of interacting particles where the mobility of any individual is determined by the population crowding at two different spatial scales. In this way we model the behavior of some biological…

Statistical Mechanics · Physics 2015-07-08 Ricardo Martínez-García , Clara Murgui , Emilio Hernández-García , Cristóbal López

We study spectral densities for systems on lattices, which, at a phase transition display, power-law spatial correlations. Constructing the spatial correlation matrix we prove that its eigenvalue density shows a power law that can be…

Mathematical Physics · Physics 2014-11-24 Vinayak , T. Prosen , B. Buca , T. H. Seligman

We show how, based on considerations on the observed form of the galaxy 2-point spatial correlation function xi(r), a very simplified -- yet surprisingly effective -- model for the linear density fluctuations power spectrum can be…

Astrophysics · Physics 2009-10-22 Enzo Branchini , Luigi Guzzo , Riccardo Valdarnini

We consider multi-energy level distributions in the SYK model, and in particular, the role of global fluctuations in the density of states of the SYK model. The connected contributions to the moments of the density of states go to zero as…

High Energy Physics - Theory · Physics 2021-10-13 Micha Berkooz , Nadav Brukner , Vladimir Narovlansky , Amir Raz

The distributions of species lifetimes and species in space are related, since species with good local survival chances have more time to colonize new habitats and species inhabiting large areas have higher chances to survive local…

Populations and Evolution · Quantitative Biology 2019-02-18 Tobias Rogge , David Jones , Barbara Drossel , Korinna T. Allhoff

Collective motion - or flocking - is an emergent phenomena that underlies many biological processes of relevance, from cellular migrations to animal groups movement. In this work, we derive scaling relations for the fluctuations of the mean…

Soft Condensed Matter · Physics 2023-02-13 Martino Brambati , Giuseppe Fava , Francesco Ginelli

Understanding the forces shaping ecological communities is crucially important to basic science and conservation. In recent years, considerable progress was made in explaining communities using simple and general models, with neutral theory…

Populations and Evolution · Quantitative Biology 2014-06-12 Michael Kalyuzhny , Ronen Kadmon , Nadav M. Shnerb

Scale invariance property in the global geometry of Earth may lead to a coupled interactive behaviour between various components of the climate system. One of the most interesting correlations exists between spatial statistics of the global…

Atmospheric and Oceanic Physics · Physics 2016-09-29 Bijan Fallah , Abbas Ali Saberi , Sahar Sodoudi

Velocity fluctuations of grains flowing down a rough inclined plane are experimentally studied. The grains at the free surface exhibit fluctuating motions, which are correlated over few grains diameters. The characteristic correlation…

Other Condensed Matter · Physics 2009-11-11 Olivier Pouliquen

Biodiversity widely observed in ecological systems is attributed to the dynamical balance among the competing species. The time-varying populations of the interacting species are often captured rather well by a set of deterministic…

Populations and Evolution · Quantitative Biology 2010-05-25 Yen-Chih Lin , Tzay-Ming Hong , Hsiu-Hau Lin

Plankton is the productive base of aquatic ecosystems and plays a major role in the global control of atmospheric carbon dioxide. Nevertheless, after intensive study, the factors that drive its spatial distribution are still far from being…

Biological Physics · Physics 2009-11-07 J. M. G. Vilar , R. V. Sole , J. M. Rubi

Experimental data are presented on particle correlations and fluctuations in various high-energy multiparticle collisions, with special emphasis on evidence for scaling-law evolution in small phase-space domains. The notions of…

High Energy Physics - Phenomenology · Physics 2009-10-28 E. A. De Wolf , I. M. Dremin , W. Kittel

Turbulence, namely, irregular fluctuations in space and time characterize fluid flows in general and atmospheric flows in particular.The irregular,i.e., nonlinear space-time fluctuations on all scales contribute to the unpredictable nature…

General Physics · Physics 2007-05-23 J. S. Pethkar , A. M. Selvam

Atmospheric flows exhibit fluctuations of all scales (space -time) ranging from turbulence (millimeters-seconds) to climate (thousands of kilometers-years). The apparently random fluctuations however exhibit long-range spatio-temporal…

chao-dyn · Physics 2009-09-25 Suvarna Fadnavis , A. M. Selvam

Secondary forests now dominate tropical landscapes and play a crucial role in achieving COP15 conservation objectives. This study develops a replicable national approach to identifying and characterising forest ecosystems, with a focus on…