2,235 research outputs found
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Powdery Mildew Caused by Podosphaera macularis on Hop (Humulus lupulus) in North Carolina
Hop (Humulus lupulus L.) production recently has expanded across the United States to include areas of the country that have not previously grown hop commercially. In June 2015, a grower in western North Carolina detected powdery mildew in a small (<0.5-ha) yard during routine scouting. Characteristic signs of powdery mildew (caused by Podosphaera macularis) were observed on cultivars ‘Cashmere’, ‘Cascade’, and ‘Chinook’. The incidence of affected leaves ranged from 0.5 to 7% among cultivars when the disease was first found, which is sufficiently severe to cause damage to cones if control measures are not implemented (Mahaffee et al. 2003). Occurrence of the disease on Cascade was of particular concern because Cascade is thought to possess some resistance to powdery mildew, although Cascade-adapted strains of P. macularis have been detected in the U.S. Pacific Northwest. Affected leaves were collected for confirmation of pathogen identity. Chasmothecia were absent. Five isolates were obtained by transferring conidia from infected leaves to healthy leaves of the powdery-mildew-susceptible cultivar Symphony. Within 7 days, powdery mildew colonies with barrel-shaped conidia and nonbranching conidiophores typical of P. macularis were visible (Ocamb et al. 1999). Two isolates from North Carolina (HPM-915 and HPM-916) and a non-Cascade-adapted isolate from Oregon (HPM-333) were each inoculated individually onto 3 leaves of Cascade (suspension of 2 × 10⁴ conidia/ml). After 10 days of incubation at 18°C, a significantly greater number of lesions developed on leaves inoculated with isolates from North Carolina as compared with a non-Cascadeadapted isolate, indicating an adaption to this cultivar. Noninoculated controls remained healthy. Similar results were obtained in two repetitions of the inoculations. To further confirm the identity of the organism as P. macularis, two isolates from North Carolina were coinoculated individually with mating type tester isolates of P. macularis confirmed to be either mating type MAT1-1 or MAT1-2 idiomorph (Wolfenbarger et al. 2015). Chasmothecia only formed when isolates were paired with a MAT1-2 isolate, indicating both isolates were P. macularis and MAT1-1 idiomorph. Mating type also was determined using PCR assays (Wolfenbarger et al. 2015), which confirmed all five isolates as MAT1-1. The PCR products were sequenced bidirectionally and compared with a sequence of P. macularis from the Pacific Northwest (GenBank Accession No. KJ922755.1). The sequences of all five isolates were identical to this accession. A representative sequence was deposited (KT899949). At present, powdery mildew occurs only sporadically in commercial yards in the eastern United States, in part because resistant cultivars are widely planted. However, powdery mildew is a damaging disease of hop and surveys are warranted to better understand the distribution of the disease on Cascade and other cultivars in the region. The isolates recovered in North Carolina may have originated from the Pacific Northwest given that only the MAT1-1 idiomorph was detected and virulence of the isolates recovered matched that of isolates only known to exist at present in the western United States
Simulation of the CMS Resistive Plate Chambers
The Resistive Plate Chamber (RPC) muon subsystem contributes significantly to
the formation of the trigger decision and reconstruction of the muon trajectory
parameters. Simulation of the RPC response is a crucial part of the entire CMS
Monte Carlo software and directly influences the final physical results. An
algorithm based on the parametrization of RPC efficiency, noise, cluster size
and timing for every strip has been developed. Experimental data obtained from
cosmic and proton-proton collisions at TeV have been used for
determination of the parameters. A dedicated validation procedure has been
developed. A good agreement between the simulated and experimental data has
been achieved.Comment: to be published in JINS
Measuring Terrestrial Area of Habitat (AOH) and Its Utility for the IUCN Red List
The International Union for Conservation of Nature (IUCN) Red List of Threatened Species includes assessment of extinction risk for 98 512 species, plus documentation of their range, habitat, elevation, and other factors. These range, habitat and elevation data can be matched with terrestrial land cover and elevation datasets to map the species’ area of habitat (AOH; also known as extent of suitable habitat; ESH). This differs from the two spatial metrics used for assessing extinction risk in the IUCN Red List criteria: extent of occurrence (EOO) and area of occupancy (AOO). AOH can guide conservation, for example, through targeting areas for field surveys, assessing proportions of species’ habitat within protected areas, and monitoring habitat loss and fragmentation. We recommend that IUCN Red List assessments document AOH wherever practical
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Measurement of jet multiplicity distributions in [Formula: see text] production in pp collisions at [Formula: see text].
The normalised differential top quark-antiquark production cross section is measured as a function of the jet multiplicity in proton-proton collisions at a centre-of-mass energy of 7[Formula: see text] at the LHC with the CMS detector. The measurement is performed in both the dilepton and lepton+jets decay channels using data corresponding to an integrated luminosity of 5.0[Formula: see text]. Using a procedure to associate jets to decay products of the top quarks, the differential cross section of the [Formula: see text] production is determined as a function of the additional jet multiplicity in the lepton+jets channel. Furthermore, the fraction of events with no additional jets is measured in the dilepton channel, as a function of the threshold on the jet transverse momentum. The measurements are compared with predictions from perturbative quantum chromodynamics and no significant deviations are observed
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Probing color coherence effects in pp collisions at [Formula: see text].
A study of color coherence effects in pp collisions at a center-of-mass energy of 7[Formula: see text] is presented. The data used in the analysis were collected in 2010 with the CMS detector at the LHC and correspond to an integrated luminosity of 36 pb[Formula: see text]. Events are selected that contain at least three jets and where the two jets with the largest transverse momentum exhibit a back-to-back topology. The measured angular correlation between the second- and third-leading jet is shown to be sensitive to color coherence effects, and is compared to the predictions of Monte Carlo models with various implementations of color coherence. None of the models describe the data satisfactorily
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Measurement of WZ and ZZ production in pp collisions at [Formula: see text] in final states with b-tagged jets.
Measurements are reported of the WZ and ZZ production cross sections in proton-proton collisions at [Formula: see text][Formula: see text] in final states where one Z boson decays to b-tagged jets. The other gauge boson, either W or Z, is detected through its leptonic decay (either [Formula: see text], [Formula: see text] or [Formula: see text], [Formula: see text], or [Formula: see text]). The results are based on data corresponding to an integrated luminosity of 18.9 fb[Formula: see text] collected with the CMS detector at the Large Hadron Collider. The measured cross sections, [Formula: see text] and [Formula: see text], are consistent with next-to-leading order quantum chromodynamics calculations
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