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Now showing items 11-20 of 233
Bacterial community structure and diversity in a century-old manure-treated agroecosystem
(American Society for Microbiology, 2004-10)
Changes in soil microbial community structure and diversity may reflect environmental impact. We examined 16S rRNA gene fingerprints of bacterial communities in six agroecosystems by PCR amplification and denaturing gradient ...
Direct optoelectronic generation and detection of sub-ps-electrical pulses on sub-mm-coaxial transmission lines
(AIP Publishing, 2004-12-20)
We report efficient direct optoelectronic generation of sub-ps-THz pulses on 50 Ohm coaxial transmission lines with a 330 micro-m diameter solid copper outer tube filled with Teflon containing the 80 micro-m diameter inner ...
Direct observation of the Gouy phase shift in THz impulse ranging
(AIP Publishing, 2000-02-07)
Here we present a direct observation of the Gouy effect through THz impulse scattering from cylindrical and spherical targets. A pi/2 Gouy phase shift through a one-axis focus compared to the more common pi phase shift of ...
Effects of dietary energy and starch concentrations for newly received feedlot calves: I. Growth performance and health
(American Society of Animal Science, 2004)
Crossbred calves (n = 572; initial BW = 186 +/= 27 kg) purchased from northern Texas, Arkansas, and southeast Oklahoma auction markets were delivered to the Willard Sparks Beef Research Center, Stillwater, OK, and used to ...
Crystal structure of Bacillus anthracis dihydrofolate reductase with the dihydrophthalazine-based trimethoprim derivative RAB1 provides a structural explanation of potency and selectivity
(American Society for Microbiology, 2009-07)
Bacillus anthracis possesses an innate resistance to the antibiotic trimethoprim due to poor binding to dihydrofolate reductase (DHFR); currently, there are no commercial antibacterials that target this enzyme in B. ...
AIDS versus the Rotterdam demand system: A Cox test with parametric bootstrap
(Western Agricultural Economics Association, 2002-12)
A Cox test with parametric bootstrap is developed to select between the linearized version of the First-Difference Almost Ideal Demand System (FDAIDS) and the Rotterdam model. A Cox test with parametric bootstrap has been ...
Measurement and noise characterization of optically induced index changes using THz interferometry
(AIP Publishing, 2004-05-24)
A Michelson interferometer designed for broadband single-cycle THz pulses is used to characterize optically induced index changes in semiconductors which result in submicron changes in optical path length. The interferometric ...
High-Q terahertz Bragg resonances within a metal parallel plate waveguide
(AIP Publishing, 2009-03-06)
One-dimensional (1D) Bragg waveguides are demonstrated at terahertz (THz) frequencies. Lithographically made 1D symmetric and asymmetric dielectric gratings on metallized high conductivity Si chips are incorporated within ...
Single-mode waveguide propagation and reshaping of sub-ps terahertz pulses in sapphire fibers
(AIP Publishing, 2000-04-10)
Waveguide propagation of sub-ps terahertz pulses in single-crystal sapphire fibers is reported. An incident THz pulse of approximately 0.6 ps duration undergoes considerable reshaping due to the absorptive and dispersive ...
Beyond forest cover: Land use and biodiversity in rubber trail forests of the Chico Mendes Extractive Reserve
(Resilience Alliance, 2009)
Among the strategies to promote sustainable tropical forest development around the world, the Federal Extractive Reserve System of Brazil is widely cited as an exemplary model. It is designed to protect rubber tapper ...