2,920 research outputs found

    Magnetization reversal and anomalous coercive field temperature dependence in MnAs epilayers grown on GaAs(100) and GaAs(111)B

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    The magnetic properties of MnAs epilayers have been investigated for two different substrate orientations: GaAs(100) and GaAs(111). We have analyzed the magnetization reversal under magnetic field at low temperatures, determining the anisotropy of the films. The results, based on the shape of the magnetization loops, suggest a domain movement mechanism for both types of samples. The temperature dependence of the coercivity of the films has been also examined, displaying a generic anomalous reentrant behavior at T>>200 K. This feature is independent of the substrate orientation and films thickness and may be associated to the appearance of new pinning centers due to the nucleation of the β\beta-phase at high temperatures.Comment: 9 pages, 7 figure

    Arkansas Cotton Variety Test 2021

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    The primary goal of the Arkansas Cotton Variety Test is to provide unbiased data regarding the agronomic performance of cotton varieties and advanced breeding lines in the major cotton-growing areas of Arkansas. This information helps seed companies establish marketing strategies and assists producers in choosing varieties to plant. These annual evaluations will then facilitate the inclusion of new, improved genetic material in Arkansas cotton production. Adaptation of varieties is determined by evaluating the lines at five University of Arkansas System Division of Agriculture research sites (Manila, Keiser, Judd Hill, Marianna, and Rohwer). The 2021 tests at Rohwer were abandoned due to excessive rain and flooding occurring on 8–9 June. Entries in the 2021 Arkansas Cotton Variety Test were evaluated in two groups—transgenic and conventional varieties. The 44 entries in the transgenic test included 3 B2XF, 30 B3XF, 10 W3FE, and 1 GLTP line, which were evaluated at all five locations. The conventional test included 16 entries which were evaluated at all locations except Manila. Reported data include lint yield, lint percentage, plant height, percent open bolls, yield component variables, fiber properties, leaf pubescence, stem pubescence, and bract trichome density. All entries in the experiments were evaluated for response to tarnished plant bug and bacterial blight in separate tests at Keiser. This 2021 report includes results of large-plot variety tests in 7 counties that were coordinated by Bill Robertson

    Arkansas Cotton Variety Test 2022

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    The primary goal of the Arkansas Cotton Variety Test is to provide unbiased data regarding the agronomic performance of cotton varieties and advanced breeding lines in the major cotton-growing areas of Arkansas. This information helps seed companies establish marketing strategies and assists producers in choosing varieties to plant. These annual evaluations will then facilitate the inclusion of new, improved genetic material in Arkansas cotton production. Adaptation of varieties is determined by evaluating the lines at five University of Arkansas System Division of Agriculture research sites (Manila, Keiser, Judd Hill, Marianna, and Rohwer). The 2022 tests at Rohwer were adversely affected by herbicides. The tests were replanted but did not achieve acceptable maturity. Yields from Rohwer are reported but not included in the overall location means. Entries in the 2022 Arkansas Cotton Variety Test were evaluated in two groups—transgenic and conventional varieties. The 40 entries in the transgenic test included 1 B2XF, 27 B3XF, 11 W3FE, and 1 GLTP line, which were evaluated at all five locations. The conventional test included 20 entries, which were evaluated at all locations except Manila. Reported data include lint yield, lint percentage, plant height, percent open bolls, yield component variables, fiber properties, leaf pubescence, stem pubescence, and bract trichome density. All entries in the experiments were evaluated for response to tarnished plant bug and bacterial blight in separate tests at Keiser. This 2022 report includes results of large-plot variety tests in 7 counties that were coordinated by Bill Robertson

    Arkansas Cotton Variety Test 2022

    Get PDF
    The primary goal of the Arkansas Cotton Variety Test is to provide unbiased data regarding the agronomic performance of cotton varieties and advanced breeding lines in the major cotton-growing areas of Arkansas. This information helps seed companies establish marketing strategies and assists producers in choosing varieties to plant. These annual evaluations will then facilitate the inclusion of new, improved genetic material in Arkansas cotton production. Adaptation of varieties is determined by evaluating the lines at five University of Arkansas System Division of Agriculture research sites (Manila, Keiser, Judd Hill, Marianna, and Rohwer). The 2022 tests at Rohwer were adversely affected by herbicides. The tests were replanted but did not achieve acceptable maturity. Yields from Rohwer are reported but not included in the overall location means. Entries in the 2022 Arkansas Cotton Variety Test were evaluated in two groups—transgenic and conventional varieties. The 40 entries in the transgenic test included 1 B2XF, 27 B3XF, 11 W3FE, and 1 GLTP line, which were evaluated at all five locations. The conventional test included 20 entries, which were evaluated at all locations except Manila. Reported data include lint yield, lint percentage, plant height, percent open bolls, yield component variables, fiber properties, leaf pubescence, stem pubescence, and bract trichome density. All entries in the experiments were evaluated for response to tarnished plant bug and bacterial blight in separate tests at Keiser. This 2022 report includes results of large-plot variety tests in 7 counties that were coordinated by Bill Robertson

    Qualitative characterization of unrefined durum wheat air-classified fractions

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    Durum wheat milling is a key process step to improve the quality and safety of final prod-ucts. The aim of this study was to characterize three bran-enriched milling fractions (i.e., F250, G230 and G250), obtained from three durum wheat grain samples, by using an innovative micronization and air-classification technology. Milling fractions were characterized for main standard quality parameters and for alveographic properties, starch composition and content, phenolic acids, antioxidant activity and ATIs. Results showed that yield recovery, ash content and particle size distributions were influenced either by the operating conditions (230 or 250) or by the grain samples. While total starch content was lower in the micronized sample and air-classified fractions, the P/L ratio increased in air-classified fractions as compared to semolina. Six main individual phenolic acids were identified through HPLC-DAD analysis (i.e., ferulic acid, vanillic acid, p-coumaric acid, sinapic acid, syringic and p-hydroxybenzoic acids). Compared to semolina, higher contents of all individual phenolic components were found in all bran-enriched fractions. The highest rise of TPAs occurred in the F250 fraction, which was maintained in the derived pasta. Moreover, bran-enriched fractions showed significant reductions of ATIs content versus semolina. Overall, our data suggest the potential health benefits of F250, G230 and G250 and support their use to make durum-based foods

    Learning algorithms estimate pose and detect motor anomalies in flies exposed to minimal doses of a toxicant

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    Pesticide exposure, even at low doses, can have detrimental effects on ecosystems. This study aimed at validating the use of machine learning for recognizing motor anomalies, produced by minimal insecticide exposure on a model insect species. The Mediterranean fruit fly, Ceratitis capitata (Diptera: Tephritidae), was exposed to food contaminated with low concentrations of Carlina acaulis essential oil (EO). A deep learning approach enabled fly pose estimation on video recordings in a custom-built arena. Five machine learning algorithms were trained on handcrafted features, extracted from the predicted pose, to distinguish treated individuals. Random Forest and K-Nearest Neighbor algorithms best performed, with an area under the receiver operating characteristic (ROC) curve of 0.75 and 0.73, respectively. Both algorithms achieved an accuracy of 0.71. Results show the machine learning potential for detecting sublethal effects arising from insecticide exposure on fly motor behavior, which could also affect other organisms and environmental health

    Response of microchannel plates to single particles and to electromagnetic showers

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    We report on the response of microchannel plates (MCPs) to single relativistic particles and to electromagnetic showers. Particle detection by means of secondary emission of electrons at the MCP surface has long been proposed and is used extensively in ion time-of-flight mass spectrometers. What has not been investigated in depth is their use to detect the ionizing component of showers. The time resolution of MCPs exceeds anything that has been previously used in calorimeters and, if exploited effectively, could aid in the event reconstruction at high luminosity colliders. Several prototypes of photodetectors with the amplification stage based on MCPs were exposed to cosmic rays and to 491 MeV electrons at the INFN-LNF Beam-Test Facility. The time resolution and the efficiency of the MCPs are measured as a function of the particle multiplicity, and the results used to model the response to high-energy showers.Comment: Paper submitted to NIM

    Natural history and clinical effect of aortic valve regurgitation after left ventricular assist device implantation

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    ObjectivesAortic valve regurgitation reduces left ventricular assist device mechanical efficiency. Evidence has also suggested that left ventricular assist device implantation can induce or exacerbate aortic valve regurgitation. However, this has not been compared with aortic valve regurgitation progression in a nonsurgical end-stage heart failure population. Furthermore, its clinical effect is unclear. We sought to characterize the development and progression of aortic valve regurgitation in left ventricular assist device recipients and to identify its clinical effect.MethodsA review of all consecutive patients who received an intracorporeal left ventricular assist device at Duke University Medical Center from January 2004 to January 2011 was conducted. Cases of previous or concomitant aortic valve surgery were excluded. Data from the remaining implants (n = 184) and a control group of contemporaneous nonsurgical patients with end-stage heart failure (n = 132) were analyzed. Serial transthoracic echocardiography was used to characterize aortic valve regurgitation as a function of time.ResultsLeft ventricular assist device implantation was associated with worsening aortic valve regurgitation, defined as an increase in aortic valve regurgitation grade, relative to the nonsurgical patients with end-stage heart failure (P < .0001). The recipients of continuous flow left ventricular assist devices were more likely than recipients of pulsatile left ventricular assist devices to develop worsening aortic valve regurgitation (P = .0348). Moderate or severe aortic valve regurgitation developed in 21 left ventricular assist device recipients; this was unrelated to the type of device implanted (continuous vs pulsatile; P = .754) or aortic valve regurgitation grade before left ventricular assist device implantation (P = .42). Five patients developed severe aortic valve regurgitation; all of whom underwent aortic valve procedures.ConclusionsNative aortic valve regurgitation developed and/or progressed after left ventricular assist device implantation, with this effect being more pronounced in continuous flow left ventricular assist device recipients. However, the preoperative aortic valve regurgitation grade failed to correlate with the development of substantial aortic valve regurgitation after left ventricular assist device implantation. After left ventricular assist device implantation, aortic valve regurgitation had a small, but discernible, clinical effect, with some patients developing severe aortic valve regurgitation and requiring aortic valve procedures. These data have implications for the long-term management of left ventricular assist device recipients, in particular as the durability of implantable continuous flow left ventricular assist device therapy improves
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