574 research outputs found

    First Report of Soybean Vein Necrosis Disease Caused by Soybean vein necrosis-associated virus in Wisconsin and Iowa

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    Several viral diseases of soybean (Glycine max) have been identified in the north-central U.S. soybean production area, which includes Wisconsin and Iowa (2). Previously, Soybean vein necrosis disease (SVND) caused by Soybean vein necrosis-associated virus was reported in Arkansas, Tennessee, and other southern states (4). In September 2012, soybean plants with symptoms similar to those reported for SVND (4) were observed in fields across Wisconsin and Iowa. Symptoms included leaf-vein and leaf chlorosis, followed by necrosis of the leaf veins and eventually necrosis of the entire leaf. Six samples with symptoms indicative of SVNaV were collected from research plots located at the West Madison Agricultural Research Station located in Madison, WI. An additional three samples were collected from three locations in central Iowa. Total RNA extracted from each sample using the Trizol Plus RNA purification kit (Invitrogen, Carlsbad, CA) was used to generate complementary DNA (cDNA) using the iScript cDNA synthesis kit (Bio-Rad Laboratories, Hercules, CA) following the manufacturers\u27 suggested protocols. The resulting cDNA was used as template in a PCR with SVNaV-specific primers, SVNaV-f1 and SVNaV-r1 (3). PCRs of two of the six Wisconsin samples and two Iowa samples were positive. Amplification products were not detected in the other five samples. The amplification products from the four strongly positive samples were purified using the Wizard SV Gel and PCR Purification Kit (Promega, Madison, WI) following the manufacturer\u27s suggested protocol and were subjected to automated sequencing (University of Wisconsin Biotechnology Center or Iowa State University, DNA Sequencing Facilities). BLASTn (1) alignments of the 915-bp consensus sequence revealed 98% and \u3e99% identity of the Wisconsin and Iowa samples, respectively, with the ‘S’ segment of the SVNaV ‘TN’ isolate (GenBank Accession No. GU722319.1). Samples from the same leaf tissue used above, were subjected to serological tests for SVNaV using antigen coated-indirect ELISA (3). Asymptomatic soybeans grown in the greenhouse were used as a source of leaves for negative controls. These tests confirmed the presence of SVNaV in eight symptomatic soybean leaflets collected in Wisconsin and Iowa. The asymptomatic control and one Iowa sample, which was also PCR-negative, were also negative by serological testing. Six additional samples from soybean fields in as many Wisconsin counties (Fond Du Lac, Grant, Green, Juneau, Richland, Rock) tested positive for SVNaV using specific primers that amplify the ‘L’ segment (4). The sequenced amplification products (297-bp) showed 99 to 100% homology to the L segment of the TN isolate (GU722317.1). To our knowledge, this is the first report of SVNaV associated with soybean and the first report of SVND in Wisconsin and Iowa. Considering that little is known about SVNaV, it is assumed that it is like other Tospoviruses and can cause significant yield loss (4). Soybean is a major cash crop for Wisconsin and Iowa, and infection by SVNaV could result in potential yield loss in years where epidemics begin early and at a high initial inoculum level

    The Global Gridded Crop Model Intercomparison: Data and modeling protocols for Phase 1 (v1.0)

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    We present protocols and input data for Phase 1 of the Global Gridded Crop Model Intercomparison, a project of the Agricultural Model Intercomparison and Improvement Project (AgMIP). The project includes global simulations of yields, phenologies, and many land-surface fluxes using 12–15 modeling groups for many crops, climate forcing data sets, and scenarios over the historical period from 1948 to 2012. The primary outcomes of the project include (1) a detailed comparison of the major differences and similarities among global models commonly used for large-scale climate impact assessment, (2) an evaluation of model and ensemble hindcasting skill, (3) quantification of key uncertainties from climate input data, model choice, and other sources, and (4) a multi-model analysis of the agricultural impacts of large-scale climate extremes from the historical record

    Electron Dephasing in Mesoscopic Metal Wires

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    The low-temperature behavior of the electron phase coherence time, τϕ\tau_{\phi}, in mesoscopic metal wires has been a subject of controversy recently. Whereas theory predicts that τϕ(T)\tau_{\phi}(T) in narrow wires should increase as T−2/3T^{-2/3} as the temperature TT is lowered, many samples exhibit a saturation of τϕ\tau_{\phi} below about 1 K. We review here the experiments we have performed recently to address this issue. In particular we emphasize that in sufficiently pure Ag and Au samples we observe no saturation of τϕ\tau_{\phi} down to our base temperature of 40 mK. In addition, the measured magnitude of τϕ\tau_{\phi} is in excellent quantitative agreement with the prediction of the perturbative theory of Altshuler, Aronov and Khmelnitskii. We discuss possible explanations why saturation of τϕ\tau_{\phi} is observed in many other samples measured in our laboratory and elsewhere, and answer the criticisms raised recently by Mohanty and Webb regarding our work.Comment: 14 pages, 3 figures; to appear in proceedings of conference "Fundamental Problems of Mesoscopic Physics", Granada, Spain, 6-11 September, 200

    Last Call for RHIC Predictions

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    This paper contains the individual contributions of all speakers of the session on 'Last Call for RHIC Predictions' at Quark Matter 99, and a summary by the convenor.Comment: 56 pages, psfig, epsf, epsfig, graphicx style files required, Proceedings of the XIV Int. Conf. on Nucleus-Nucleus Collisions, Quark Matter 99, Torino, Italy, May 10 - 15, 1999. Typographical mistakes corrected and figure numbers change

    Levels and equivalence in credit and qualifications frameworks: Contrasting the prescribed and enacted curriculum in school and college

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    Drawing on data from an empirical study of three matched subjects in upper secondary school and further education college in Scotland, this article explores some of the factors that result in differences emerging from the translation of the prescribed curriculum into the enacted curriculum. We argue that these differences raise important questions about equivalences which are being promoted through the development of credit and qualifications frameworks. The article suggests that the standardisation associated with the development of a rational credit and qualifications framework and an outcomes-based prescribed curriculum cannot be achieved precisely because of the multiplicity that emerges from the practices of translation

    Experimental and Theoretical Challenges in the Search for the Quark Gluon Plasma: The STAR Collaboration's Critical Assessment of the Evidence from RHIC Collisions

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    We review the most important experimental results from the first three years of nucleus-nucleus collision studies at RHIC, with emphasis on results from the STAR experiment, and we assess their interpretation and comparison to theory. The theory-experiment comparison suggests that central Au+Au collisions at RHIC produce dense, rapidly thermalizing matter characterized by: (1) initial energy densities above the critical values predicted by lattice QCD for establishment of a Quark-Gluon Plasma (QGP); (2) nearly ideal fluid flow, marked by constituent interactions of very short mean free path, established most probably at a stage preceding hadron formation; and (3) opacity to jets. Many of the observations are consistent with models incorporating QGP formation in the early collision stages, and have not found ready explanation in a hadronic framework. However, the measurements themselves do not yet establish unequivocal evidence for a transition to this new form of matter. The theoretical treatment of the collision evolution, despite impressive successes, invokes a suite of distinct models, degrees of freedom and assumptions of as yet unknown quantitative consequence. We pose a set of important open questions, and suggest additional measurements, at least some of which should be addressed in order to establish a compelling basis to conclude definitively that thermalized, deconfined quark-gluon matter has been produced at RHIC.Comment: 101 pages, 37 figures; revised version to Nucl. Phys.

    The exposure of the hybrid detector of the Pierre Auger Observatory

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    The Pierre Auger Observatory is a detector for ultra-high energy cosmic rays. It consists of a surface array to measure secondary particles at ground level and a fluorescence detector to measure the development of air showers in the atmosphere above the array. The "hybrid" detection mode combines the information from the two subsystems. We describe the determination of the hybrid exposure for events observed by the fluorescence telescopes in coincidence with at least one water-Cherenkov detector of the surface array. A detailed knowledge of the time dependence of the detection operations is crucial for an accurate evaluation of the exposure. We discuss the relevance of monitoring data collected during operations, such as the status of the fluorescence detector, background light and atmospheric conditions, that are used in both simulation and reconstruction.Comment: Paper accepted by Astroparticle Physic

    Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

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    A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results
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