University of Texas at Arlington

About: University of Texas at Arlington is a education organization based out in Arlington, Texas, United States. It is known for research contribution in the topics: Population & Large Hadron Collider. The organization has 11758 authors who have published 28598 publications receiving 801626 citations. The organization is also known as: UT Arlington & University of Texas-Arlington.

Robust nonnegative matrix factorization using L21-norm

Abstract: Nonnegative matrix factorization (NMF) is widely used in data mining and machine learning fields. However, many data contain noises and outliers. Thus a robust version of NMF is needed. In this paper, we propose a robust formulation of NMF using L21 norm loss function. We also derive a computational algorithm with rigorous convergence analysis. Our robust NMF approach, (1) can handle noises and outliers; (2) provides very efficient and elegant updating rules; (3) incurs almost the same computational cost as standard NMF, thus potentially to be used in more real world application tasks. Experiments on 10 datasets show that the robust NMF provides more faithful basis factors and consistently better clustering results as compared to standard NMF.

Stoichiometric relationships among producers, consumers and nutrient cycling in pelagic ecosystems

Abstract: Most ecosystem models consolidate members of food-webs, e.g. species, into a small number of functional components. Each of these is then described by a single state variable such as biomass. When a multivariate approach incorporating multiple substances within components is substituted for this univariate one, a ‘stoichiometric’ model is formed. Here we show that the Nitrogen:Phosphorus ratio within zooplankton herbivores varies substantially intraspecifically but not intraspecifically. By using stoichiometric theory and recent measurements of the N:P ratio within different zooplankton taxa, we calculate large differences in ratios of nutrients recycled by different zooplankton species. Finally, we demonstrate that N:P stoichiometry can successfully account for shifts in N- and P-limitation previously observed in whole-lake experiments. Species stoichiometry merges food-web dynamics with biogeochemical cycles to yield new insights.

Antioxidant Role of Glutathione S-Transferases: Protection Against Oxidant Toxicity and Regulation of Stress-Mediated Apoptosis

Abstract: It has been known that glutathione S-transferases (GSTs) can reduce lipid hydroperoxides through their Se-independent glutathione peroxidase activity and that these enzymes can also detoxify lipid peroxidation end products such as 4-hydroxynonenal (4-HNE). In this article, recent studies suggesting that the Alpha class GSTs provide a formidable defense against oxidative stress are critically evaluated and the role of these enzymes in the regulation of oxidative stress-mediated signaling is reviewed. Available evidence from earlier studies together with results of recent studies in our laboratories strongly suggests that lipid peroxidation products, particularly hydroperoxides and 4-HNE, are involved in the mechanisms of stress-mediated signaling and that it can be modulated by the Alpha class GSTs through the regulation of the intracellular concentrations of 4-HNE.

Reflection and transmission guided-mode resonance filters

Abstract: New reflection and transmission optical filters based on guided-mode resonances in multilayer waveguide gratings are characterized and compared with homogeneous thin-film filters. These guided-mode resonance filters are implemented by integration of diffraction gratings into classical thin-film multilayers to produce high-efficiency filter response and arbitrarily low sidebands extended over a large spectral range. Compared with homogeneous thin-film reflection filters, guided-mode resonance reflection filters require significantly fewer layers for a narrow linewidth and a high peak response to be obtained. The single-grating transmission filters presented have a narrower linewidth than Fabry–Perot filters with an equal number of layers and similar materials while maintaining high peak transmittance and low sidebands.