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Visibility scintillation resulting from wave propagation through the turbulent ionosphere can be an important sources of noise at low radio frequencies ($\nu\lesssim 200$ MHz). Many low frequency experiments are underway to detect the power…

Instrumentation and Methods for Astrophysics · Physics 2016-03-16 H. K. Vedantham , L. V. E. Koopmans

We build a full spectral-timing model for the low/hard state of black hole binaries assuming that the spectrum of the X-ray hot flow can be produced by two Comptonisation zones. Slow fluctuations generated at the largest radii/softest…

High Energy Astrophysical Phenomena · Physics 2018-03-13 Ra'ad D. Mahmoud , Chris Done

Two mathematical models of macroevolution are studied. These models have population dynamics at the species level, and mutations and extinction of species are also included. The population dynamics are updated by difference equations with…

Populations and Evolution · Quantitative Biology 2014-04-16 Yohsuke Murase , Takashi Shimada , Nobuyasu Ito , Per Arne Rikvold

We consider an extension of the noisy $N$-Branching Random Walk that models the evolution of a population subject to natural selection. We show the existence of a critical value for the noise which separates the limiting genealogical…

Populations and Evolution · Quantitative Biology 2025-03-17 Emmanuel Schertzer , Alejandro H. Wences

The effect of stochasticity, in the form of Gaussian white noise, in a predator-prey model with two distinct time-scales is presented. A supercritical singular Hopf bifurcation yields a Type II excitability in the deterministic model. We…

Dynamical Systems · Mathematics 2017-07-20 Susmita Sadhu

We consider a directed abelian sandpile on a strip of size $2\times n$, driven by adding a grain randomly at the left boundary after every $T$ time-steps. We establish the exact equivalence of the problem of mass fluctuations in the steady…

Statistical Mechanics · Physics 2015-06-04 Avinash Chand Yadav , Ramakrishna Ramaswamy , Deepak Dhar

Species populations often modify their environment as they grow. When environmental feedback operates more slowly than population growth, the system can undergo boom-bust dynamics, where the population overshoots its carrying capacity and…

Populations and Evolution · Quantitative Biology 2026-05-27 Pablo Moreno-Spiegelberg , Javier Aguilar

The power from wind and solar exhibits a nonlinear flickering variability, which typically occurs at time scales of a few seconds. We show that high-frequency monitoring of such renewable powers enables us to detect a transition, controlled…

Physics and Society · Physics 2016-10-17 M. Anvari , G. Lohmann , M. Reza Rahimi Tabar , M. Wächter , P. Milan , D. Heinemann , Joachim Peinke , E. Lorenz

Characterizing charge noise is of prime importance to the semiconductor spin qubit community. We analyze the echo amplitude data from a recent experiment [Yoneda et al., Nat. Nanotechnol. 13, 102 (2018)] and note that the data shows small…

Mesoscale and Nanoscale Physics · Physics 2019-02-22 Utkan Güngördü , J. P. Kestner

We present the Lyman-$\alpha$ flux power spectrum measurements of the XQ-100 sample of quasar spectra obtained in the context of the European Southern Observatory Large Programme "Quasars and their absorption lines: a legacy survey of the…

We report the first upper limits on the power spectrum of 21-cm fluctuations during the Epoch of Reionization and Cosmic Dawn from Phase II of the Hydrogen Epoch of Reionization Array (HERA) experiment. HERA Phase II constitutes several…

Cosmology and Nongalactic Astrophysics · Physics 2025-11-27 The HERA Collaboration , Zuhra Abdurashidova , Tyrone Adams , James E. Aguirre , Rushelle Baartman , Rennan Barkana , Lindsay M. Berkhout , Gianni Bernardi , Tashalee S. Billings , Bruno B. Bizarria , Judd D. Bowman , Daniela Breitman , Philip Bull , Jacob Burba , Ruby Byrne , Steven Carey , Rajorshi Sushovan Chandra , Kai-Feng Chen , Samir Choudhuri , Tyler Cox , David R. DeBoer , Eloy de Lera Acedo , Matt Dexter , Jiten Dhandha , Joshua S. Dillon , Scott Dynes , Nico Eksteen , John Ely , Aaron Ewall-Wice , Nicolas Fagnoni , Anastasia Fialkov , Steven R. Furlanetto , Kingsley Gale-Sides , Hugh Garsden , Adelie Gorce , Deepthi Gorthi , Ziyaad Halday , Bryna J. Hazelton , Jacqueline N. Hewitt , Jack Hickish , Tian Huang , Daniel C. Jacobs , Alec Josaitis , Nicholas S. Kern , Joshua Kerrigan , Piyanat Kittiwisit , Matthew Kolopanis , Adam Lanman , Paul La Plante , Adrian Liu , Yin-Zhe Ma , David H. E. MacMahon , Lourence Malan , Cresshim Malgas , Keith Malgas , Bradley Marero , Zachary E. Martinot , Lisa McBride , Andrei Mesinger , Jordan Mirocha , Nicel Mohamed-Hinds , Mathakane Molewa , Miguel F. Morales , Julian B. Muñoz , Steven G. Murray , Bojan Nikolic , Hans Nuwegeld , Aaron R. Parsons , Robert Pascua , Nipanjana Patra , Simon Pochinda , Yuxiang Qin , Eleanor Rath , Nima Razavi-Ghods , Daniel Riley , Kathryn Rosie , Mario G. Santos , Saurabh Singh , Dara Storer , Hilton Swarts , Jianrong Tan , Emilie Thélie , Pieter van Wyngaarden , Michael J. Wilensky , Peter K. G. Williams , Haoxuan Zheng

This paper explores a stochastic Gause predator-prey model with bounded or sub-linear functional response. The model, described by a system of stochastic differential equations, captures the influence of stochastic fluctuations on…

Populations and Evolution · Quantitative Biology 2024-09-10 Leon Alexander Valencia , Ph. D , Jorge Mario Ramirez Osorio , Jorge Andres Sanchez

The Sinai model of a tracer diffusing in a quenched Brownian potential is a much studied problem exhibiting a logarithmically slow anomalous diffusion due to the growth of energy barriers with the system size. However, if the potential is…

Statistical Mechanics · Physics 2016-10-05 David S. Dean , Antonio Iorio , Enzo Marinari , Gleb Oshanin

We measure the linear power spectrum of mass density fluctuations at redshift z=2.5 from the \lya forest absorption in a sample of 19 QSO spectra, using the method introduced by Croft et al. (1998). The P(k) measurement covers the range…

Astrophysics · Physics 2009-10-31 Rupert A. C. Croft , David H. Weinberg , Max Pettini , Lars Hernquist , Neal Katz

Paleo-Sciences including palaeoclimatology and palaeoecology have accumulated numerous records related to climatic changes. The researchers have usually tried to identify periodic and quasi-periodic processes in these paleoscientific…

Statistic dynamics of financial systems is investigated, basing on a model of randomly coupled equation system driven by stochastic Langevin force. It is found that in stable regime the noise power spectrum of the system is of 1/f^alpha…

Disordered Systems and Neural Networks · Physics 2008-12-02 Kestutis Staliunas

This paper investigates the influence of environmental noise on the characteristic timescale of the dynamics of density-dependent populations. General results are obtained on the statistics of time spent in rarity and time spent in…

Probability · Mathematics 2007-05-23 R. Ferriere , A. Guionnet , I. Kurkova

Universal conductance fluctuations are usually observed in the form of aperiodic oscillations in the magnetoresistance of thin wires as a function of the magnetic field B. If such oscillations are completely random at scales exceeding…

Disordered Systems and Neural Networks · Physics 2021-12-28 I. M. Suslov

We carried out an extensive RXTE campaign, in 1997 June, to study Circinus X-1 during the active portion of its 16.55-d intensity cycle. The observations spanned 10 days, including 56% coverage for 7 d, and allowed us to find time segments…

Astrophysics · Physics 2009-10-31 Robert E. Shirey , Hale V. Bradt , Alan M. Levine

Fast radio bursts (FRBs) are extragalactic astrophysical transients whose brightness requires emitters that are highly energetic, yet compact enough to produce the short, millisecond-duration bursts. FRBs have thus far been detected between…