There appears to exist a conflict between the standard structure formation theory and the existence of the faint dwarf spheroidal galaxies in the Local Group. Theoretical considerations suggest that a cold dark matter universe has been a very hostile place for the formation of small galaxies. In particular, gas would not have been able to cool and condense to form stars inside dark matter halos...

Clouds are of paramount importance for the global energy balance and, thereby, our climate. Changes in cloud cover and phase (liquid water versus ice), for example, through increased greenhouse forcing, may have significant and as of yet unknown impacts on our climate. The global climate models (GCMs) designed to predict future climate, usually model the effects of clouds using the scattering a...

Mechanical milling of aluminum powders with two immiscible liquids, acetonitrile and hexane, produced roughly spherical particles increased flowability sizes in the range tens to hundreds microns specific surface areas 15 – 30 m2/g. The near shapes comprised agglomerated flakes. Samples were milled from 0.5 2 hours a planetary mill. Longer times led reduced sizes, while porosity area peaked at ...

in the present paper, resonant frequencies and modes of a three-atom photonic molecule and a photonic crystal placed within a cavity are numerically calculated. first, governing formulation in transverse electric field mode (te) is obtained using maxwell equations. then, an algorithm based on a finite difference scheme and matrix algebra is presented. the algorithm is then implemented in a comp...

For xed c, Prolate Spheroidal Wave Functions (PSWFs), denoted by ψn,c, form an orthogonal basis with remarkable properties for the space of band-limited functions with bandwith c. They have been largely studied and used after the seminal work of D. Slepian and his co-authors. In several applications, uniform estimates of the ψn,c in n and c, are needed. To progress in this direction, we push fo...

An important problem in communication engineering is the energy concentration problem, that is the problem of finding a signal bandlimited to [−σ, σ] with maximum energy concentration in the interval [−τ, τ ], 0 < τ, in the time domain, or equivalently, finding a signal that is time limited to the interval [−τ, τ ] with maximum energy concentration in [−σ, σ] in the frequency domain. This probl...

Many systems of orthogonal polynomials and functions are bases of a variety of function spaces, such as the Hermite and Laguerre functions which are orthogonal bases of L2(−∞,∞) and L2(0,∞), and the Jacobi polynomials which are an orthogonal basis of a weighted L2(−1, 1). The associated Legendre functions, and more generally, the spheroidal wave functions are also an orthogonal basis of L2(−1, ...