Leptonic Observables in Ultra-Relativistic Heavy Ion Collisions

We report on leptonic observables by the PHENIX experiment from data taken during Run II at the Relativistic Heavy Ion Collider (RHIC). We show first results on phi -> K+K-, e+e-, low and intermediate mass dielectron continuum, single electrons from charm, and J/psi yields in proton-proton and Au-Au collisions at sqrt{s_{NN}}=200 GeV.Comment: 10 pages, 11 figures, Talk presented at Quark Matter 2002, Nantes, France, July 18-24, 2002. To appear in the proceedings (Nucl. Phys. A

Brane Intersections in the Presence of a Worldvolume Electric Field

The study of brane intersections has provided important insights into a possible non-commutative structure of spacetime geometry. In this paper we focus on the D1$\bot$D3 system. We compare the D1 and D3 descriptions of the interesection and search for non-static solutions of the D3$\bot$D1 funnel equations in the presence of a worldvolume electric field. We find that the D1 and D3 descriptions do not agree. We find time dependent solutions that are a natural generalization of those found without the electric field.Comment: 10 page

Erratum

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/46187/1/205_2004_Article_BF00249672.pd

Running coupling constants of the Luttinger liquid

Two running coupling constants of the Luttinger liquid are computed in the fermion-fermion and fermion-antifermion channels. Nontrivial scaling laws are found together with Landau poles. The apparent contradiction with the expected vanishing of the beta functions is explained.Comment: Final version, to appear in Phys. Lett.

Random forests with random projections of the output space for high dimensional multi-label classification

We adapt the idea of random projections applied to the output space, so as to enhance tree-based ensemble methods in the context of multi-label classification. We show how learning time complexity can be reduced without affecting computational complexity and accuracy of predictions. We also show that random output space projections may be used in order to reach different bias-variance tradeoffs, over a broad panel of benchmark problems, and that this may lead to improved accuracy while reducing significantly the computational burden of the learning stage

On thin plate spline interpolation

We present a simple, PDE-based proof of the result [M. Johnson, 2001] that the error estimates of [J. Duchon, 1978] for thin plate spline interpolation can be improved by $h^{1/2}$. We illustrate that ${\mathcal H}$-matrix techniques can successfully be employed to solve very large thin plate spline interpolation problem

Floodplain restoration enhances denitrification and reach-scale nitrogen removal in an agricultural stream

Streams of the agricultural Midwest, USA, export large quantities of nitrogen, which impairs downstream water quality, most notably in the Gulf of Mexico. The two-stage ditch is a novel restoration practice, in which floodplains are constructed alongside channelized ditches. During high flows, water flows across the floodplains, increasing benthic surface area and stream water residence time, as well as the potential for nitrogen removal via denitrification. To determine two-stage ditch nitrogen removal efficacy, we measured denitrification rates in the channel and on the floodplains of a two-stage ditch in north-central Indiana for one year before and two years after restoration. We found that instream rates were similar before and after the restoration, and they were influenced by surface water $\text{NO}_{3}^{−}$ concentration and sediment organic matter content. Denitrification rates were lower on the constructed floodplains and were predicted by soil exchangeable $\text{NO}_{3}^{−}$ concentration. Using storm flow simulations, we found that two-stage ditch restoration contributed significantly to $\text{NO}_{3}^{−}$ removal during storm events, but because of the high $\text{NO}_{3}^{−}$ loads at our study site, <10% of the $\text{NO}_{3}^{−}$ load was removed under all storm flow scenarios. The highest percentage of $\text{NO}_{3}^{−}$ removal occurred at the lowest loads; therefore, the two-stage ditch's effectiveness at reducing downstream N loading will be maximized when the practice is coupled with efforts to reduce N inputs from adjacent fields

Mass Determination Method for the Right and Left Selectron Above Production Threshold

The determination of the masses of Supersymmetric particles such as the Selectron for energies above threshold using the energy end-points method is subject to signal deconvolution difficulties and to Standard Model and Supersymmetric backgrounds. The important features of Right and Left Selectron production are used to design an experimentally robust method both for determining the Left and Right Selectron masses, the Neutralino mass and for suppresing backgrounds. The mass resolution is an order of magnitude better than in previous methods. Additional features, such as the determination of the relative leptonic branching ratios of the selectron decay are present in the method.Comment: 4 pages in RevTex (Latex) format and 4 figures in eps forma