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.

Design of waveguide-grating filters with symmetrical line shapes and low sidebands.

Abstract: We show that ideal reflection filters can be designed by combining guided-mode resonance effects in waveguide gratings with antireflection effects of thin-film structures. Since the guided-mode resonance effect overrides the antireflection effect this filter provides a symmetrical line shape with near-zero reflectivity over appreciable wavelength bands adjacent to the resonance wavelength. In the single-layer filter the same layer functions as the waveguide grating supporting the resonance and as the antireflection layer suppressing reflection around the resonance. A multilayer design allows the filter resonance peak to have a wide surrounding region of low reflectance. The central resonance wavelength, the filter linewidth, the range of the low sidebands, and the resonance line shape are all under the control of the designer.

Pangea and the Paleogeography of the Permian

Abstract: In this chapter we review the paleogeographic and plate tectonic setting of the supercontinent of Pangea during the Early Permian (mid-Sakmarian) and the Late Permian (Kazanian). The paleogeographic reconstructions presented in Figs. 6 through 13 are based on the paleogeographIc maps assembled by the PALEOMAP Project (International Lithosphere Program) (Scotese and Golonka 1995) and have been revised to include information provided by authors of this Volume, as well as the recent paleogeographic syntheses published in the Decade of North American Geology and by Langford (1992), Yemane and Kelts (1990), Visser (1993), and other authors for the Gondwana continents.

Direct and indirect evidence of size-selective grazing on pelagic bacteria by freshwater nanoflagellates.

Abstract: Size-selective grazing of three heterotrophic nanoflagellates (with cell sizes of 21, 44, and 66 mum) isolated from Lake Arlington, Texas was examined by using a natural mixture of fluorescence labelled lake bacteria. Sizes of ingested bacteria in food vacuoles were directly measured. Larger bacterial cells were ingested at a frequency much higher than that at which they occurred in the assemblage, indicating preferential flagellate grazing on the larger size classes within the lake bacterioplankton. Water samples were collected biweekly from June through September, 1989, fractionated by filtration, and incubated for 40 h at in situ temperatures. The average bacterial size was always larger in water which was passed through 1-mum-pore-size filters (1-mum-filtered water) (which was predator free) than in 5-mum-filtered water (which contained flagellates only) or in unfiltered water (in which all bacterivores were present). The increase of bacterial-cell size in 1-mum-filtered water was caused by a shift in the size structure of the bacterioplankton population. Larger cells became more abundant in the absence of flagellate grazing.