Clarinet Studio Recital

Clarinet Studio RecitalMagda Adamek, Chris Reed and Daniel Stipe, pianoSunday, February 16, 2020 at 7pmRecital HallJames W. Black Music Center1015 Grove AvenueRichmond, Va

One-point statistics and intermittency of induced electric field in the solar wind

The interplanetary induced electric field e=vxb is studied, using solar wind time series. The probability distribution functions (PDFs) of the electric field components are measured from the data and their non-gaussianity is discussed. Moreover, for the first time we show that the electric field turbulence is characterized by intermittency. This point is addressed by studying, as usual, the scaling of the PDFs of field increments, which allows a quantitative characterization of intermittency.Comment: Accepted for publication on Europhysics Letters, April 22th, 200

On the turbulent energy cascade in anisotropic magnetohydrodynamic turbulence

The problem of the occurrence of an energy cascade for Alfv\'enic turbulence in solar wind plasmas was hystorically addressed by using phenomenological arguments based to the weakness of nonlinear interactions and the anisotropy of the cascade in wave vectors space. Here, this paradox is reviewed through the formal derivation of a Yaglom relation from anisotropic Magnetohydrodynamic equation. The Yaglom relation involves a third-order moment calculated from velocity and magnetic fields and involving both Els\"asser vector fields, and is particularly useful to be used as far as spacecraft observations of turbulence are concerned

Faculty Recital, Tiffany Valvo, clarinet

Faculty RecitalTiffany Valvo, clarinetDaniel Stipe, pianoTuesday, February 26. 2019 at 12noonRecital Hall / James W. Black Music Center1015 Grove Avenue / Richmond, Virgini

Non-gaussian probability distribution functions in two dimensional Magnetohydrodynamic turbulence

Intermittency in MHD turbulence has been analyzed using high resolution 2D numerical simulations. We show that the Probability Distribution Functions (PDFs) of the fluctuations of the Elsasser fields, magnetic field and velocity field depend on the scale at hand, that is they are self-affine. The departure of the PDFs from a Gaussian function can be described through the scaling behavior of a single parameter lambda_r^2 obtained by fitting the PDFs with a given curve stemming from the analysis of a multiplicative model by Castaing et al. (1990). The scaling behavior of the parameter lambda_r^2 can be used to extract informations about the intermittency. A comparison of intermittency properties in different MHD turbulent flows is also performed.Comment: 7 pages, with 5 figure

Statistical Separation of Objects in Shadows from Objects in Daylight in an Aerial Scene

Objects photographed in an aerial scene are ordered into frequency histograms in terms of log exposure on the film. A statistical analysis shows that each distribution actually contains two separate distributions; one of objects in daylight, the other of objects in shadows. The difference is due to a variation in apparent luminance of the objects. For example, as an asphalt road passes in and out of a shadow, its absolute reflectance doesn\u27t change but its apparent luminance does. It is also shown that the ratio of the derived shadow distribution to the daylight distribution is exactly the same as the ratio of skylight to daylight illumination

Mitochondrial heteroplasmy in an avian hybrid form (Passer italiae: Aves, Passeriformes)

Mitochondrial heteroplasmy is the result from biparental transmission of mitochondrial DNA (mtDNA) to the offspring. In such rare cases, maternal and paternal mtDNA is present in the same individual. Though recent studies suggested that mtDNA heteroplasmy might be more common than previously anticipated, that phenomenon is still poorly documented and was mostly detected in case studies on hybrid populations. The Italian sparrow, Passer italiae is a homoploid hybrid form that occurs all across the Italian Peninsula mostly under strict absence of either of its parent species, the house sparrow (P. domesticus) and the Spanish sparrow (P. hispaniolensis). In this study, we document a new case of mitochondrial heteroplasmy from two island populations of P. italiae (Ustica and Lipari). Our analysis was based on the mitochondrial NADH dehydrogenase subunit 2 (ND2) that allows for a clear distinction between mitochondrial lineages of the two parental species. We amplified and sequenced the mitochondrial ND2 gene with specifically designed primer combinations for each of the two parental species. In two of our study populations, a single individual carried two different ND2 haplotypes from each of the two parental lineages. These findings contribute to current knowledge on the still poorly documented phenomenon of paternal leakage in vertebrates