274 research outputs found

    Nesting Chronology of South Dakota Ducks

    Get PDF
    Duck broods were censused on 476 randomly selected plots in South Dakota during July of the years 1973 through 1976. Broods were also censused on wetlands located off the study plots both in July and August of these years, except in 1976 when no August counts were made. Hatching and nest initiation dates were determined by back dating from brood age classes. Early nesting species were mallards (Anas platyrhynchos) and pintails (A. acuta). Northern shovelers (A. clypeata), redheads (Aythya americana), and canvasbacks (A. valisineria) were intermediate nesters while blue-winged teal (Anas discors), gadwalls (A. strepera), and American wigeons (A. americana) were late nesters. Mallards and pintails initiated nests over the longest periods of time. Variables associated with wetland habitat, temperature, and physiography were examined by multiple regression to see if these factors influenced nest initiation dates, Results of the analyses were inconclusive. There is probably not enough variation in most of these aspects across South Dakota to allow statistical perception of potential relationships with nest initiation dates. I suggest that this type of analysis be applied to data collected over a much broader and more diverse area, the entire prairie pothole region

    GWAS for Fusarium Head Blight Related Traits in Winter Wheat (\u3cem\u3eTriticum Aestivum\u3c/em\u3e L.) in an Artificially Warmed Treatment

    Get PDF
    Global temperature increases will affect Fusarium head blight (FHB) levels in wheat (Triticum aestivum L.). A pressing question is whether current sources of resistance will be effective in a warmer environment. We evaluated phenotypic response to disease in 238 soft winter wheat breeding lines and cultivars grown in 2015–2016 and 2016–2017 under control and warmed (+3 °C) conditions. Warming was achieved with heating cables buried 3 cm in the rhizosphere. We measured heading date, plant height, yield, FHB rating, Fusarium damaged kernels (FDK), deoxynivalenol (DON), leaf blotch rating, powdery mildew rating and leaf rust rating. There were significant (p \u3c 0.01) differences among genotypes for all traits measured. Genome-wide association study (GWAS) identified 19 and 10 significant SNPs in the control and warmed treatments, respectively. FDK and DON levels were often significantly (p \u3c 0.05) higher in warmed than in control when we contrasted alleles at important quantitative trait locus (QTL) such as Fhb1, Rht-B1 and D1 and all vernalization and photoperiod loci. Increased rhizosphere temperature resulted in a significantly (p \u3c 0.01) earlier heading date (~3.5 days) both years of the study. Rank correlation between warmed and control treatments was moderate (r = 0.56). Though encouraging, it indicates that selection for performance under warming should be carried out in a warmed environment

    Hybrid Beam-Steering OFDM-MIMO Radar: High 3-D Resolution With Reduced Channel Count

    Get PDF
    We report on the realization of a multichannel imaging radar that achieves uniform 2-D cross-range resolution by means of a linear array of a special form of leaky-wave antennas. The presented aperture concept enables a tradeoff between the available range resolution and a reduction in the number of channels required for a given angular resolution. The antenna front end is integrated within a multichannel radar based on stepped-carrier orthogonal frequency-division modulation, and the advantages and challenges specific to this combination are analyzed with respect to signal processing and a newly developed calibration routine. The system concept is fully implemented and verified in the form of a mobile demonstrator capable of soft real-time 3-D processing. By combining radio frequency (RF) components operating in the W-band (85-105 GHz) with the presented aperture, a 3-D resolution of less than 1.5° x 1.5° x 15 cm is demonstrated using only eight transmitters and eight receivers

    Broadband 300-GHz Power Amplifier MMICs in InGaAs mHEMT Technology

    Get PDF
    In this article, we report on compact solid-state power amplifier (SSPA) millimeter-wave monolithic integrated circuits (MMICs) covering the 280–330-GHz frequency range. The technology used is a 35-nm gate-length InGaAs metamorphic highelectron- mobility transistor (mHEMT) technology. Two power amplifier MMICs are reported, based on a compact unit amplifier cell, which is parallelized two times using two different Wilkinson power combiners. The Wilkinson combiners are designed using elevated coplanar waveguide and air-bridge thin-film transmission lines in order to implement low-loss 70-Ω lines in the back-endof-line of this InGaAs mHEMT technology. The five-stage SSPA MMICs achieve a measured small-signal gain around 20 dB over the 280–335-GHz frequency band. State-of-the-art output power performance is reported, achieving at least 13 dBm over the 286–310-GHz frequency band, with a peak output power of 13.7 dBm (23.4 mW) at 300 GHz. The PA MMICs are designed for a reduced chip width while maximizing the total gate width of 512 μm in the output stage, using a compact topology based on cascode and common-source devices, improving the output power per required chip width significantly

    Caracterização morfo-fisiológica e patogenicidade de Colletotrichum gloeosporioides da pupunheira.

    Get PDF
    Isolados de Colletotorichum sp. de folhas de pupunheira (Bactris gasipaes) com sintomas de antracnose foram comparados fenotipicamente, visando a sua caracterização e identificação. Foram analisados 17 isolados, oriundos dos Estados do Acre, Rondônia, Espírito Santo, São Paulo e Paraná. Caracterizaram- se os sintomas da doença e os isolados foram comparados em relação à forma e tamanho de conídios e apressórios, e quanto a coloração das colônias, crescimento micelial e esporulação em meio de cultura. A patogenicidade dos isolados foi confirmada em folhas de pupunheira destacadas. Todos os isolados foram identificados como Colletotrichum gloeosporioides e a fase meiospórica in vitro (Glomerella cingulata) ocorreu apenas em um isolado procedente de Linhares, Espírito Santo
    • …
    corecore