Identification and mapping of a leaf rust resistance gene in barley line Q21861

Barley line Q21861 possesses an incompletely dominant gene (RphQ) for resistance to leaf rust caused by Puccinia hordei. To investigate the allelic and linkage relations between RphQ and other known Rph genes, F2 populations from crosses between Q21861 and donors of Rph1 to Rph14 (except for Rph8) were evaluated for leaf rust reaction at the seedling stage. Results indicate that RphQ is either allelic with or closely linked to the Rph2 locus. A doubled haploid population derived from a cross between Q21861 and SM89010 (a leaf rust susceptible line) was used for molecular mapping of the resistance locus. Bulked segregant analysis was used to identify markers linked to RphQ, using random amplified polymorphic DNAs (RAPDs), restriction fragment length polymorphisms (RFLPs), and sequence tagged sites (STSs). Of 600 decamer primers screened, amplified fragments generated by 9 primers were found to be linked to the RphQ locus; however, only 4 of them were within 10 cM of the target. The RphQ locus was mapped to the centromeric region of chromosome 7, with a linkage distance of 3.5 cM from the RFLP marker CDO749. Rrn2, an RFLP clone from the ribosomal RNA intergenic spacer region, was found to be very closely linked with RphQ, based on bulked segregant analysis. An STS marker, ITS1, derived from Rrn2, was also closely linked (1.6 cM) to RphQ

Regions of the genome that affect agronomic performance in two-row barley

Quantitative trait locus (QTL) main effects and QTL by environment (QTL × E) interactions for seven agronomic traits (grain yield, days to heading, days to maturity, plant height, lodging severity, kernel weight, and test weight) were investigated in a two-row barley (Hordeum vulgare L.) cross, Harrington/TR306. A 127-point base map was constructed from markers (mostly RFLP) scored in 146 random double-haploid (DH) lines from the Harrington/TR306 cross. Field experiments involving the two parents and 145 random DH lines were grown in 1992 and/or 1993 at 17 locations in North America. Analysis of QTL was based on simple and composite interval mapping. Primary QTL were declared at positions where both methods gave evidence for QTL. The number of primary QTL ranged from three to six per trait, collectively explaining 34 to 52% of the genetic variance. None of these primary QTL showed major effects, but many showed effects that were consistent across environments. The addition of secondary QTL gave models that explained 39 to 80% of the genetic variance. The QTL were dispersed throughout the barley genome and some were detected in regions where QTL have been found in previous studies. Eight chromosome regions contained pleiotropic loci and/or linked clusters of loci that affected multiple traits. One region on chromosome 7 affected all traits except days to heading. This study was an intensive effort to evaluate QTL in a narrow-base population grown in a large set of environments. The results reveal the types and distributions of QTL effects manipulated by plant breeders and provide opportunities for future testing of marker-assisted selection

Design and performance of a 35-ton liquid argon time projection chamber as a prototype for future very large detectors

Liquid argon time projection chamber technology is an attractive choice for large neutrino detectors, as it provides a high-resolution active target and it is expected to be scalable to very large masses. Consequently, it has been chosen as the technology for the first module of the DUNE far detector. However, the fiducial mass required for "far detectors" of the next generation of neutrino oscillation experiments far exceeds what has been demonstrated so far. Scaling to this larger mass, as well as the requirement for underground construction places a number of additional constraints on the design. A prototype 35-ton cryostat was built at Fermi National Acccelerator Laboratory to test the functionality of the components foreseen to be used in a very large far detector. The Phase I run, completed in early 2014, demonstrated that liquid argon could be maintained at sufficient purity in a membrane cryostat. A time projection chamber was installed for the Phase II run, which collected data in February and March of 2016. The Phase II run was a test of the modular anode plane assemblies with wrapped wires, cold readout electronics, and integrated photon detection systems. While the details of the design do not match exactly those chosen for the DUNE far detector, the 35-ton TPC prototype is a demonstration of the functionality of the basic components. Measurements are performed using the Phase II data to extract signal and noise characteristics and to align the detector components. A measurement of the electron lifetime is presented, and a novel technique for measuring a track's position based on pulse properties is described

Long-Baseline Neutrino Facility (LBNF) and Deep Underground Neutrino Experiment (DUNE) Conceptual Design Report Volume 2: The Physics Program for DUNE at LBNF

The Physics Program for the Deep Underground Neutrino Experiment (DUNE) at the Fermilab Long-Baseline Neutrino Facility (LBNF) is described

Impacts of bus rapid transit (BRT) on residential property values: A comparative analysis of 11 US BRT systems

Bus rapid transit (BRT) is growing in popularity as a lower-cost alternative to light rail transit. Although the impacts of rail transportation on residential property values is well-explored, the impact of BRT on property values remains less well-understood, particularly in the United States where BRT infrastructure is more heterogeneous than the rest of the world. This paper addresses this gap by evaluating and comparing the before-and-after effect of 11 BRT systems on nearby property values in ten metropolitan areas across the United States. We used a quasi-experimental approach and hedonic spatial error models with propensity score matching to measure change in residential property transaction prices within walking distance of a BRT station. Overall model results show a mix of appreciation, depreciation, and no change in residential properties value across different BRT systems. Multi-family properties nearby BRTs with on-street dedicated lanes generally experienced the most appreciation while single-family properties around off-street busway systems experienced depreciation. BRT-lite systems without dedicated lanes associate with property appreciation in relatively dense and congested metropolitan areas with developed transit networks and high ridership. Our model results emphasize the ability of BRT to improve transit accessibility in these regions and to provide an attractive alternative to driving. Furthermore, the lack of property appreciation around busways indicates these systems may not provide nearby residents with an amenity bonus greater than its nuisance effects. Our study informs stakeholders and public officials about the broad effects of BRT on land values and invites researchers to continue investigating the role of walkability, nuisance effects, and individual BRT amenities on residential property values

Different Ways of Weakening Decision Trees and Their Impact on Classification Accuracy of DT Combination

info:eu-repo/semantics/publishe

Boosting in Linear Discriminant Analysis

. In recent years, together with bagging [5] and the random subspace method [15], boosting [6] became one of the most popular combining techniques that allows us to improve a weak classifier. Usually, boosting is applied to Decision Trees (DT's). In this paper, we study boosting in Linear Discriminant Analysis (LDA). Simulation studies, carried out for one artificial data set and two real data sets, show that boosting might be useful in LDA for large training sample sizes while bagging is useful for critical training sample sizes [11]. In this paper, in contrast to a common opinion, we demonstrate that the usefulness of boosting does not depend on the instability of a classifier.