There is large interspecific variation in the magnitude of population fluctuations, even among closely related species. The factors generating this variation are not well understood, primarily because of the challenges of separating the relative impact of variation in population size from fluctuations in the environment. Here, we show using demographic data from 13 bird populations that magnitu...

We will in this paper report on suggestive similarities between density fluctuation power versus wavenumber on small (mm) and large (Mpc) scales. The small scale measurements were made in fusion plasmas and compared to predictions from classical fluid turbulence theory. The data is consistent with the dissipative range of 2D turbulence. Alternatively, the results can be fitted to a functional f...

Density and magnetic fluctuations arising spontaneously in a narrow field-aligned density striation in a magnetized discharge He plasma are found to exhibit a radial eigenmode structure. The nature of the fluctuations depends upon the electron plasma beta, be . For be greater than the electron to ion mass ratio (be.m/M ) the frequency spectrum exhibits sharply peaked eigenfrequencies with the d...

Changes in cell size often accompany multicellular motion in tissue, and cell number density is known to strongly influence collective migration in monolayers. Density fluctuations in other forms of active matter have been explored extensively, but not the potential role of density fluctuations in collective cell migration. Here we investigate collective motion in cell monolayers, focusing on t...

An iterative procedure is developed with the aim of constructing homogeneity rules for the distribution P (ρ, δ) of the particle density ρ at resolution scale δ. A single iteration step consists of a change in the normalization point of P (ρ, δ) followed by a rescaling. Similar transformation rule is introduced for density fluctuations contaminated by Poisson noise. Application of the iterative...

The propagation of microwaves across a turbulent plasma density layer is investigated with fullwave simulations. To properly represent a fusion edge-plasma, drift-wave turbulence is considered based on the Hasegawa-Wakatani model. Scattering and broadening of a microwave beam whose amplitude distribution is of Gaussian shape is studied in detail as a function of certain turbulence properties. P...

The characterization of density fluctuations in systems of interacting particles is of fundamental importance in the physical sciences. We present a formalism for studying local density fluctuations in two special subvolumes ~centered around either a reference particle or some arbitrary point in the system! termed particle and void regions, respectively. We present formal expressions for the pr...

We analyze the energy density fluctuations contributed by scalar fields Φ with vanishing expectation values, 〈Φ〉 = 0, which are present in addition to the inflaton field. For simplicity we take Φ to be non–interacting and minimally coupled to gravity. We use normal ordering to define the renormalized energy density operator ρ, and we show that any normal ordering gives the same result for corre...

In this paper we study the evolution of primordial density perturbations in the framework of Phase Coupling Gravity, proposed by Bekenstein [1]. We show that in the very early universe, these perturbations grow with an exponential-like behaviour PACS: 98.80.-k, 04.50.+h e.mail: [email protected] e.mail: [email protected]

A Yukawa-like equation, introduced to evaluate the first order correlation function in a Bose-Einstein condensate, can be used to evaluate the atomic density fluctuations. It does not require a few mode approximation. We apply this approach to calculate the atomic fluctuations of a condensate of attractive atoms in a double-well potential. The atomic system undergoes a spatial symmetry breaking...