37,177 research outputs found
Recent Detections of a Rare Native Lady Beetle, \u3ci\u3eCoccinella Novemnotata\u3c/i\u3e (Coleoptera: Coccinellidae), in Minnesota
Coccinella novemnotata Herbst (Coleoptera: Coccinellidae) was once widespread and commonly collected in North America; however, its abundance and distribution decreased over the 1970s and 1980s. It has not been collected by recent surveys in some areas and in other areas is only rarely collected. Museum records were examined and a survey of Minnesota soybean fields was conducted via sweep-net sampling in July and August 2011. Results suggest that C. novemnotata is absent from or below the detection threshold in the majority of the state of Minnesota. However, there appears to be an area in east central Minnesota with at least sustained low, but detectable populations of C. novemnotata and it is active in agricultural crops
One-way coherent imaging through a distorting medium using four-wave mixing
A proposal and an analysis are presented for imaging through a distorting medium using field multiplication by four-wave mixing
Remotely operated gripper provides vertical control rod movement
Remote actuation of a gripper shaft affects vertical engagement between a drive shaft and control rod. A secondary function of the gripper is to provide remote indication of positive completion of the gripping or ungripping operation
High heat flux actively cooled honeycomb sandwich structural panel for a hypersonic aircraft
The results of a program to design and fabricate an unshielded actively cooled structural panel for a hypersonic aircraft are presented. The design is an all-aluminum honeycomb sandwich with embedded cooling passages soldered to the inside of the outer moldline skin. The overall finding is that an actively cooled structure appears feasible for application on a hypersonic aircraft, but the fabrication process is complex and some material and manufacturing technology developments are required. Results from the program are summarized and supporting details are presented
Isotopic ecology of coyotes from scat and road kill carcasses: A complementary approach to feeding experiments.
Scat is frequently used to study animal diets because it is easy to find and collect, but one concern is that gross fecal analysis (GFA) techniques exaggerate the importance of small-bodied prey to mammalian mesopredator diets. To capitalize on the benefits of scat, we suggest the analysis of scat carbon and nitrogen isotope values (δ13C and δ15N). This technique offers researchers a non-invasive method to gather short-term dietary information. We conducted three interrelated studies to validate the use of isotopic values from coyote scat: 1) we determined tissue-to-tissue apparent C and N isotope enrichment factors (ε13* and ε15*) for coyotes from road kill animals (n = 4); 2) we derived diet-to-scat isotope discrimination factors for coyotes; and 3) we used field collected coyote scats (n = 12) to compare estimates of coyote dietary proportions from stable isotope mixing models with estimates from two GFA techniques. Scat consistently had the lowest δ13C and δ15N values among the tissues sampled. We derived a diet-to-scat Δ13C value of -1.5‰ ± 1.6‰ and Δ15N value of 2.3‰ ± 1.3‰ for coyotes. Coyote scat δ13C and δ15N values adjusted for discrimination consistently plot within the isotopic mixing space created by known dietary items. In comparison with GFA results, we found that mixing model estimates of coyote dietary proportions de-emphasize the importance of small-bodied prey. Coyote scat δ13C and δ15N values therefore offer a relatively quick and non-invasive way to gain accurate dietary information
Analysis And Performance Of A Picosecond Dye Laser Amplifier Chain
Design considerations are discussed for a simple, easy to use and relatively efficient high gain dye laser amplifier chain for CW mode-locked dye lasers. The amplifier boosts the output of a synchronously mode-locked dye laser to obtain ≈005 mj, ≤ 1 psec pulses over a ≈ 400 Å bandwidth. These pulses are suitable for efficient Raman Shifting, frequency mixing and continuum generation to vastly extend the spectral range of the system. Our amplifier is pumped by a frequency doubled Nd:YAG oscillator only, which longitudinally pumps three identical brewster cells with the same flowing dye solution in each. Contrary to popular belief, high small signal gains (≥ 105) are easily attained in a single stage with longitudinal pumping, with better beam homogeneity and easier alignment than transverse pumping. Gain saturation measurements are presented which agree well with calculations. Factors which relax the pump timing sensitivity are examined. The importance of gain saturation for both efficient amplification and for amplitude stability is also discussed. The need for isolated amplifier stages is stressed and optimal amplifier cell areas for a given stage are calculated
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