7,367 research outputs found

    Residual Action of Slow Release Systemic Insecticides on \u3ci\u3eRhopalosiphum Padi\u3c/i\u3e (Homoptera: Aphididae) on Wheat

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    Slow release formulations of acephate and carbofuran encapsulated in pearl corn­ starch or corn flour granules were applied to the soil at seeding time of potted \u27Caldwell\u27 wheat in the laboratory. Dosages of these insecticides were adjusted to a standard of IO kg/ha of a 10 10 granular formulation of carbofuran. The residual action of these insecticide treatments against Rhopalosiphum padi were compared with those obtained with that of carbofuran 150 at corresponding dosages and foliar sprays of solutions of acephate (25 10 EC) at 0.2 10 and carbofuran (4F) at 1.25 10, applied 12 d after seedling emergence. The residual action of carbofuran 150, which controlled R. padi since seedling emergence, lasted 28.5 d. The slow release granular formulations of carbofuran began to provide control (\u3e 50 10 aphid mortality) on days 13.3 and 17.9 after seeding. They controlled the insect until days 31.6 and 35.5 after seeding. The two corresponding granular formulations of acephate began to provide control on days 15.0 and 17.0 after seeding and con­ trolled the aphids until days 31.5 and 32.8 after seeding. The foliar sprays of acephate and carbofuran provided control for 18.3 and 36.2 d from application, respectively. The slow release granular formulations provided control of R. padi, an important vector of barley yellow dwarf virus, during early. stages of wheat development

    Adaptive multi-scale retinex algorithm for contrast enhancement of real world scenes

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    Contrast enhancement is a classic image restoration technique that traditionally has been performed using forms of histogram equalization. While effective these techniques often introduce unrealistic tonal rendition in real-world scenes. This paper explores the use of Retinex theory to perform contrast enhancement of real-world scenes. We propose an improvement to the Multi-Scale Retinex algorithm which enhances its ability to perform dynamic range compression while not introducing halo artifacts and greying. The algorithm is well suited to be implemented on the GPU and by doing so real-time processing speeds are achieved

    Characterisation of Cryogenic Material Properties of 3D-Printed Superconducting Niobium using a 3D Lumped Element Microwave Cavity

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    We present an experimental characterisation of the electrical properties of 3D-printed Niobium. The study was performed by inserting a 3D-printed Nb post inside an Aluminium cylindrical cavity, forming a 3D lumped element re-entrant microwave cavity resonator. The resonator was cooled to temperatures below the critical temperature of Niobium (9.25K) and then Aluminium (1.2K), while measuring the quality factors of the electromagnetic resonances. This was then compared with finite element analysis of the cavity and a measurement of the same cavity with an Aluminium post of similar dimensions and frequency, to extract the surface resistance of the Niobium post. The 3D-printed Niobium exhibited a transition to the superconducting state at a similar temperature to the regular Niobium, as well as a surface resistance of 3.1×1043.1\times10^{-4} Ω\Omega. This value was comparable to many samples of traditionally machined Niobium previously studied without specialised surface treatment. Furthermore, this study demonstrates a simple new method for characterizing the material properties of a relatively small and geometrically simple sample of superconductor, which could be easily applied to other materials, particularly 3D-printed materials. Further research and development in additive manufacturing may see the application of 3D-printed Niobium in not only superconducting cavity designs, but in the innovative technology of the future.Comment: 5 pages, 4 figure

    Investigating the DNA-Binding Site for VirB, a Key Transcriptional Regulator of Shigella Virulence Genes, Using an In Vivo Binding Tool

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    The transcriptional anti-silencing and DNA-binding protein, VirB, is essential for the virulence of Shigella species and, yet, sequences required for VirB-DNA binding are poorly understood. While a 7-8 bp VirB-binding site has been proposed, it was derived from studies at a single VirB-dependent promoter, icsB. Our previous in vivo studies at a different VirB-dependent promoter, icsP, found that the proposed VirB-binding site was insufficient for regulation. Instead, the required site was found to be organized as a near-perfect inverted repeat separated by a single nucleotide spacer. Thus, the proposed 7-8 bp VirB-binding site needed to be re-evaluated. Here, we engineer and validate a molecular tool to capture protein-DNA binding interactions in vivo. Our data show that a sequence organized as a near-perfect inverted repeat is required for VirB-DNA binding interactions in vivo at both the icsB and icsP promoters. Furthermore, the previously proposed VirB-binding site and multiple sites found as a result of its description (i.e., sites located at the virB, virF, spa15, and virA promoters) are not sufficient for VirB to bind in vivo using this tool. The implications of these findings are discussed

    Self-stigma and weight loss: The impact of fear of being stigmatized

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    The current study sought to examine whether two facets of weight self-stigma (fear of enacted stigma and self-devaluation) were associated with weight change and treatment engagement for 188 individuals participating in a 3-month online weight loss program. Fear of enacted stigma predicted less weight loss 3-months later after controlling for demographics, eating problems, and psychological symptoms. Self-devaluation did not predict weight loss. Neither weight self-stigma variable predicted engagement in the online program. These results add to the literature indicating the negative effects of weight self-stigma while highlighting the central role of fear of being stigmatized by others in this process

    Preserved collagen reveals species identity in archaeological marine turtle bones from Caribbean and Florida sites

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    Advancements in molecular science are continually improving our knowledge of marine turtle biology and evolution. However, there are still considerable gaps in our understanding, such as past marine turtle distributions, which can benefit from advanced zooarchaeological analyses. Here, we apply collagen fingerprinting to 130 archaeological marine turtle bone samples up to approximately 2500 years old from the Caribbean and Florida's Gulf Coast for faunal identification, finding the vast majority of samples (88%) to contain preserved collagen despite deposition in the tropics. All samples can be identified to species-level with the exception of the Kemp's ridley (Lepidochelys kempii) and olive ridley (L. olivacea) turtles, which can be separated to genus level, having diverged from one another only approximately 5 Ma. Additionally, we identify a single homologous peptide that allows the separation of archaeological green turtle samples, Chelonia spp., into two distinct groups, which potentially signifies a difference in genetic stock. The majority of the archaeological samples are identified as green turtle (Chelonia spp.; 63%), with hawksbill (Eretmochelys imbricata; 17%) and ridley turtles (Lepidochelys spp.; 3%) making up smaller proportions of the assemblage. There were no molecular identifications of the loggerhead turtle (Caretta caretta) in the assemblage despite 9% of the samples being morphologically identified as such, highlighting the difficulties in relying on morphological identifications alone in archaeological remains. Finally, we present the first marine turtle molecular phylogeny using collagen (I) amino acid sequences and find our analyses match recent phylogenies based on nuclear and mitochondrial DNA. Our results highlight the advantage of using collagen fingerprinting to supplement morphological analyses of turtle bones and support the usefulness of this technique for assessing their past distributions across the Caribbean and Florida's Gulf Coast, especially in these tropical environments where DNA preservation may be poor

    Transistor Circuits

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    Contains reports on three research projects

    Point-Mass Aircraft Trajectory Prediction Using a Hierarchical, Highly-Adaptable Software Design

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    A highly adaptable and extensible method for predicting four-dimensional trajectories of civil aircraft has been developed. This method, Behavior-Based Trajectory Prediction, is based on taxonomic concepts developed for the description and comparison of trajectory prediction software. A hierarchical approach to the "behavioral" layer of a point-mass model of aircraft flight, a clear separation between the "behavioral" and "mathematical" layers of the model, and an abstraction of the methods of integrating differential equations in the "mathematical" layer have been demonstrated to support aircraft models of different types (in particular, turbojet vs. turboprop aircraft) using performance models at different levels of detail and in different formats, and promise to be easily extensible to other aircraft types and sources of data. The resulting trajectories predict location, altitude, lateral and vertical speeds, and fuel consumption along the flight path of the subject aircraft accurately and quickly, accounting for local conditions of wind and outside air temperature. The Behavior-Based Trajectory Prediction concept was implemented in NASA's Traffic Aware Planner (TAP) flight-optimizing cockpit software application
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