Medium Modifications of the Rho Meson at CERN/SPS Energies

Rho meson propagation in hot hadronic matter is studied in a model with coupling to $\pi\pi$ states. Medium modifications are induced by a change of the pion dispersion relation through collisions with nucleons and $\Delta's$ in the fireball. Maintaining gauge invariance dilepton production is calculated and compared to the recent data of the CERES collaboration in central S+Au collisions at 200 GeV/u. The observed enhancement of the rate below the rho meson mass can be largely accounted for.Comment: 10 pages RevTeX and 2 figures (uuencoded .ps-files

Photon production in relativistic nuclear collisions at SPS and RHIC energies

Chiral Lagrangians are used to compute the production rate of photons from the hadronic phase of relativistic nuclear collisions. Special attention is paid to the role of the pseudovector a_1 meson. Calculations that include reactions with strange mesons, hadronic form factors and vector spectral densities consistent with dilepton production, as well as the emission from a quark-gluon plasma and primordial nucleon-nucleon collisions, reproduce the photon spectra measured at the Super Proton Synchrotron (SPS). Predictions for the Relativistic Heavy Ion Collider (RHIC) are made.Comment: Work presented at the 26th annual Montreal-Rochester-Syracuse-Toronto conference (MRST 2004) on high energy physics, Montreal, QC, Canada, 12-14 May 2004. 8 pages, 3 figure

Photon and dilepton emission rates from high density quark matter

We compute the rates of real and virtual photon (dilepton) emission from dense QCD matter in the color-flavor locked (CFL) phase, focusing on results at moderate densities (3-5 times the nuclear saturation density) and temperatures $T\simeq80$ MeV. We pursue two approaches to evaluate the electromagnetic (e.m.) response of the CFL ground state: (i) a direct evaluation of the photon self energy using quark particle/-hole degrees of freedom, and (ii) a Hidden Local Symmetry (HLS) framework based on generalized mesonic excitations where the $\rho$ meson is introduced as a gauge boson of a local SU(3) color-flavor group. The $\rho$ coupling to generalized two-pion states induces a finite width and allows to address the issue of vector meson dominance (VMD) in the CFL phase. We compare the calculated emissivities (dilepton rates) to those arising from standard hadronic approaches including in-medium effects. For rather large superconducting gaps (several tens of MeV at moderate densities), as suggested by both perturbative and nonperturbative estimates, the dilepton rates from CFL quark matter turn out to be very similar to those obtained in hadronic many-body calculations, especially for invariant masses above $M\simeq0.3$ GeV. A similar observation holds for (real) photon production.Comment: 18 pages, 12 figure

Flavour compounds of clones from different grape varieties

The selection of highly productive and characteristic clones is essential for the maintenance and improvement of the viticultural and commercially valuable qualities of certain grape varieties. In the future, this very difficult and time consuming selection of adapted clones will be supplemented with more precise analytical techniques. In this regard, GC analysis will be most valuable. Analytically, German white wines can be divided into three groups by the content of only a few monoterpene compounds ('terpene profiles'): 'Riesling', 'Muscat' and 'Sylvaner' or 'Weissburgunder' types. Furthermore, the use of linear discriminant analysis on some components allows the differentiation within types (e. g. for 'Riesling'-tpye: Riesling, Müller-Thurgau, Bacchus, Kerner, Ehrenfelser, Scheurebe). Till now no significant differentiation could be made from flavour compounds of Riesling clones, although clear differences can be perceived between wines from Traminer clones. Wines with a low sensory appraisal typically have a low content of monoterpene compounds. Differences can also be recognized in the aroma profiles of Chardonnay clones, allowing an analytical differentiation between aromatic and non-aromatic types. Certain clones, however, show differing compositions of flavour compounds when grown in different areas (clones with an 'unstable' aromatic character). Also during ripening of the berries, differences occur within individual Chardonnay clones, resulting in a few clones having recognizable ripening curves for monoterpene compounds

Evaluating chiral symmetry restoration through the use of sum rules

We pursue the idea of assessing chiral restoration via in-medium modifications of hadronic spectral functions of chiral partners. The usefulness of sum rules in this endeavor is illustrated, focusing on the vector and axial-vector channels. We first present an update on constructing quantitative results for pertinent vacuum spectral functions. These spectral functions serve as a basis upon which the in-medium spectral functions can be constructed. A striking feature of our analysis of the vacuum spectral functions is the need to include excited resonances, dictated by satisfying the Weinberg-type sum rules. This includes excited states in both the vector and axial-vector channels. Preliminary results for the finite temperature vector spectral function are presented. Based on a rho spectral function tested in dilepton data which develops a shoulder at low energies, we find that the rho' peak flattens off. The flattening may be a sign of chiral restoration, though a study of the finite temperature axial-vector spectral function remains to be carried out.Comment: 9 pages, conference proceedings from Resonance Workshop at UT Austin, March 5-7 201

Exploring the effects of natural language justifications in food recommender systems

Users of food recommender systems typically prefer popular recipes, which tend to be unhealthy. To encourage users to select healthier recommendations by making more informed food decisions, we introduce a methodology to generate and present a natural language justification that emphasizes the nutritional content, or health risks and benefits of recommended recipes. We designed a framework that takes a user and two food recommendations as input and produces an automatically generated natural language justification as output, which is based on the user’s characteristics and the recipes’ features. In doing so, we implemented and evaluated eight different justification strategies through two different justification styles (e.g., comparing each recipe’s food features) in an online user study (N = 503). We compared user food choices for two personalized recommendation approaches, popularity-based vs our health-aware algorithm, and evaluated the impact of presenting natural language justifications. We showed that comparative justifications styles are effective in supporting choices for our healthy-aware recommendations, confirming the impact of our methodology on food choices

Exploring the effects of natural language justifications in food recommender systems

Users of food recommender systems typically prefer popular recipes, which tend to be unhealthy. To encourage users to select healthier recommendations by making more informed food decisions, we introduce a methodology to generate and present a natural language justification that emphasizes the nutritional content, or health risks and benefits of recommended recipes. We designed a framework that takes a user and two food recommendations as input and produces an automatically generated natural language justification as output, which is based on the user's characteristics and the recipes' features. In doing so, we implemented and evaluated eight different justification strategies through two different justification styles (e.g., comparing each recipe's food features) in an online user study (N = 503). We compared user food choices for two personalized recommendation approaches, popularity-based vs our health-aware algorithm, and evaluated the impact of presenting natural language justifications. We showed that comparative justifications styles are effective in supporting choices for our healthy-aware recommendations, confirming the impact of our methodology on food choices