10,320 research outputs found

    First U.S. records of Amorbia concavana (Zeller) (Lepidoptera: Tortricidae)

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    Amorbia concavana (Zeller) (Lepidoptera: Tortricidae) is reported in Florida, USA. Male and female specimens are figured, and new host records are given. The species is compared to other Nearctic species of Amorbia Clemens. Florida specimens are more similar to Cuban than to Central American material with respect to male genitalia

    Sufetula Walker in Florida (Lepidoptera: Crambidae)

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    The two species of Sufetula Walker (Lepidoptera: Crambidae) occurring in Florida are reviewed based on adult specimens. Sufetula carbonalis n. sp. is described, Sufetula diminutalis (Walker) is diagnosed, and they are differentiated from related Caribbean species and similar sympatric Crambidae. Both are occasional root pests of ornamental palms. Unusual structural characters suggest that Sufetula is misclassified in Spilomelinae

    Insecticide and Growth Regulator Effects on the Leafminer, \u3ci\u3eLiriomyza Trifolii\u3c/i\u3e (Diptera: Agromyzidae), in Celery and Observations on Parasitism

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    The effects of different insecticides were compared on survival and development of the leafminer, L. trifolii, in celery in Michigan and parasitism was assessed in this non- resident population. Avermectin, thiocyclam, and cyromazine effectively controlled L. trifolii larvae or prevented successful emergence as adults. Moderate to high levels of resistance to permethrin and chlorpyrifos were present. Avermectin caused high mortality of all larval stages and no adults successfully emerged. Thiocyclam caused high mortality to all larval stages, but did not affect adult emergence from the surviving larvae. Cyromazine acted most strongly against early stage larvae before visible mines were present, caused little direct mortality of larger larvae, but prevented successful adult emergence. No parasitoids emerged from 2029 larvae collected and reared, in contrast to studies in sites where L. trifolii is a year-round resident

    Price Dispersion and Accessibility: A Case study of Fast Food

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    This study examines spatial variation in the price and accessibility of fast food across a major urban area. We use novel data on the price of a representative fast food meal and the location of fast food restaurants belonging to one of three major chains in the District of Columbia and its surrounding suburbs. These data are used to test a structural model of spatial competition. The results of this study are easily interpreted and compared with a past analysis. We find that spatial differences in costs and demand conditions drive variation in the number of firms operating in a market, which in turn affects prices.food prices, food accessibility, spatial competition, price dispersion, fast food

    Prediction and reduction of rotor broadband noise

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    Prediction techniques which can be or have been applied to subsonic rotors, and methods for designing helicopter rotors for reduced broadband noise generation are summarized. It is shown how detailed physical models of the noise source can be used to identify approaches to noise control

    Space processing of crystals for opto-electronic devices: The case for solution growth

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    The results obtained during a six month program aimed at determining the viability of space processing in the 1980's of dielectric-elastic-magnetic single crystals were described. The results of this program included: identification of some important emerging technologies dependent on dielectric-elastic-magnetic crystals, identification of the impact of intrinsic properties and defects in the single crystals on system performance, determination of a sensible common basis for the many crystals of this class, and identification of the benefits of micro-gravity and some initial experimental evidence that these benefits can be realized in space. It is concluded that advanced computers and optical communications are at a development stage for high demand of dielectric-elastic-magnetic single crystals in the mid-1980's. Their high unit cost and promise for significantly increased perfection by growth in space justified pursuit of space processing

    Sources, paths, and concepts for reduction of noise in the test section of the NASA Langley 4x7m wind tunnel

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    NASA is investigating the feasibility of modifying the 4x7m Wind Tunnel at the Langley Research Center to make it suitable for a variety of aeroacoustic testing applications, most notably model helicopter rotors. The amount of noise reduction required to meet NASA's goal for test section background noise was determined, the predominant sources and paths causing the background noise were quantified, and trade-off studies between schemes to reduce fan noise at the source and those to attenuate the sound generated in the circuit between the sources and the test section were carried out. An extensive data base is also presented on circuit sources and paths

    Correction: assortative mating in fallow deer reduces the strength of sexual selection.

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    PMCID: PMC3182158 This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.This article corrects this one: PLoS One. 2011; 6(4): e18533. doi:10.1371/journal.pone.0018533[This corrects the article on p. e18533 in vol. 6.]

    PDEs with Compressed Solutions

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    Sparsity plays a central role in recent developments in signal processing, linear algebra, statistics, optimization, and other fields. In these developments, sparsity is promoted through the addition of an L1L^1 norm (or related quantity) as a constraint or penalty in a variational principle. We apply this approach to partial differential equations that come from a variational quantity, either by minimization (to obtain an elliptic PDE) or by gradient flow (to obtain a parabolic PDE). Also, we show that some PDEs can be rewritten in an L1L^1 form, such as the divisible sandpile problem and signum-Gordon. Addition of an L1L^1 term in the variational principle leads to a modified PDE where a subgradient term appears. It is known that modified PDEs of this form will often have solutions with compact support, which corresponds to the discrete solution being sparse. We show that this is advantageous numerically through the use of efficient algorithms for solving L1L^1 based problems.Comment: 21 pages, 15 figure

    Shoreline configuration and shoreline dynamics: A mesoscale analysis

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    The author has identified the following significant results. Atlantic coast barrier island shorelines are seldom straight, but rather sinuous. These shoreline curvatures range in size from cusps to capes. Significant relationships exist between the orientation of shoreline segments within the larger of these sinuous features and shoreline dynamics, with coefficients ranging up to .9. Orientation of the shoreline segments of Assateague Island (60 km) and the Outer Banks of North Carolina (130 km) was measured from LANDSAT 2 imagery (1:80,000) and high altitude aerial photography (1:120,000). Long term trends in shoreline dynamics were established by mapping shoreline and storm-surge penetration changes
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