1,568 research outputs found
Heritability of peach tree resistance to bacterial leaf spot.
The objective of this work was to evaluate the broad-sense heritability reaction to bacterial leaf spot (Xanthomonas arboricola pv. pruni), in peach tree populations obtained from directed crosses. Disease severity and defoliation of the genotypes were evaluated in field conditions, with posterior measurement of the healthy leaf area duration (HAD). The observed average heritability (0.51) indicates that the use of the evaluated genitors can be effective for the development of cultivars with higher resistance to the disease.Notas CientĂficas. TĂtulo em portuguĂȘs: Herdabilidade de resistĂȘncia de pessegueiro Ă bacteriose foliar
Off-shell effects in dilepton production from hot interacting mesons
The production of dielectrons in reactions involving a_1 mesons and pions is
studied. We compare results obtained with different phenomenological
Lagrangians that have been used in connection with hadronic matter and finite
nuclei. We insist on the necessity for those interactions to satisfy known
empirical properties of the strong interaction. Large off-shell effects in
dielectron production are found and some consequences for the interpretation of
heavy ion data are outlined. We also compare with results obtained using
experimentally-extracted spectral functions.Comment: 14 pages, LaTeX2e, 2 figure
Machine learning prediction models for mitral valve repairability and mitral regurgitation recurrence in patients undergoing surgical mitral valve repair
Background: Mitral valve regurgitation (MR) is the most common valvular heart disease and current variables associated with MR recurrence are still controversial. We aim to develop a machine learning-based prognostic model to predict causes of mitral valve (MV) repair failure and MR recurrence. Methods: 1000 patients who underwent MV repair at our institution between 2008 and 2018 were enrolled. Patients were followed longitudinally for up to three years. Clinical and echocardiographic data were included in the analysis. Endpoints were MV repair surgical failure with consequent MV replacement or moderate/severe MR (>2+) recurrence at one-month and mod-erate/severe MR recurrence after three years. Results: 817 patients (DS1) had an echocardiographic examination at one-month while 295 (DS2) also had one at three years. Data were randomly divided into training (DS1: n = 654; DS2: n = 206) and validation (DS1: n = 164; DS2 n = 89) cohorts. For intra-operative or early MV repair failure assessment, the best area under the curve (AUC) was 0.75 and the complexity of mitral valve prolapse was the main predictor. In predicting moderate/severe recurrent MR at three years, the best AUC was 0.92 and residual MR at six months was the most important predictor. Conclusions: Machine learning algorithms may improve prognosis after MV repair procedure, thus improving indications for correct candidate selection for MV surgical repair
Performance of clonal rootstocks for "BRS-Kampai" peach and own-rooted trees in a mild-winter region.
Abstract: The worldwide main peach-producing are adopting peach training systems with canopy size-controlling clonal rootstocks. However, most peach seedlings commercialised in Brazil are still on seed-propagated rootstocks, which are vigorous and heterogeneous. This study aimed to select rootstocks which induce desirable characteristics of fruit quality, yield efficiency, size control, adaptability and stability in the âBRS-Kampaiâ grown in subtropical regions with mild winters. We used adaptability and stability methodology and multivariate selection index to determine yield components and fruit quality. The experiment was conducted in five cycles. The treatments consisted of âBRS-Kampaiâ grafted onto 17 clonal rootstocks of Prunus spp. and own-rooted trees. The evaluated variables were yield per tree, yield per area, fruit mass, fruit diameter, fruit firmness, soluble solids content, titratable acidity, canopy volume and yield efficiency. The rootstocks âIshtaraÂźâ, âGenovesaâ, âSanta Rosaâ and âCadamanâ always induced low yield and low fruit quality when used as clonal rootstocks for the âBRS-Kampaiâ and showed no potential for use as rootstocks in subtropical humid regions with mild winters. The âBRS-Kampaiâ own-rooted peach trees or those grafted onto âFlordaguardâ, âOkinawaâ are alternatives for peach cultivation under the edaphoclimatic conditions of Pato Branco-PR, although the training and pruning systems must be adjusted due to high vigour. The clonal rootstocks âTsukuba-3â and âTsukuba-2â induced the highest production performance in the canopy cultivar BRS-Kampai, combining fruit quality, yield with higher stability, and yield efficiency making them the most suitable ones among the studied rootstocks. Resumo: Sistemas de condução de pessegueiros com porta-enxertos clonais que reduzem vigor da copa sĂŁo os mais adotados mundialmente. Entretanto, no Brasil ainda se utiliza porta-enxertos propagados por sementes, que sĂŁo vigorosos e heterogĂȘneos. Este trabalho teve como objetivo selecionar porta-enxertos que induzam qualidade de frutos, eficiĂȘncia produtiva, controle de vigor, adaptabilidade e estabilidade em âBRS-Kampaiâ cultivada em regiĂ”es subtropicais com invernos amenos. Foram utilizadas metodologias de adaptabilidade e estabilidade e Ăndice de seleção multivariada para determinar os componentes de produção e qualidade dos frutos. O experimento foi conduzido em cinco ciclos. Os tratamentos consistiram de pessegueiro âBRS-Kampaiâ autoenraizado ou enxertado em 17 porta-enxertos clonais de Prunus spp. As variĂĄveis avaliadas foram produção por planta, produtividade por ĂĄrea, massa de frutos, diĂąmetro e firmeza de frutos, teor de sĂłlidos solĂșveis, acidez titulĂĄvel, volume de copa e eficiĂȘncia produtiva. Em regiĂ”es subtropicais com invernos âIshtaraÂźâ, âGenovesaâ, âSanta Rosaâ e âCadamanâ induziram baixa produtividade e baixa qualidade de frutos na âBRS-Kampaiâ e nĂŁo apresentam potencial para uso como porta-enxertos. âBRS-Kampaiâ autoenraizadas ou enxertadas em âFlordaguardâ e âOkinawaâ sĂŁo alternativas para o cultivo do pessegueiro, embora os sistemas de condução e poda devam ser ajustados devido ao alto vigor. Os porta-enxertos clonais âTsukuba-3â e âTsukuba-2â induziram o maior desempenho produtivo na âBRS-Kampaiâ, aliando qualidade de frutos, produtividade com maior estabilidade e eficiĂȘncia produtiva tornando-os os mais indicados entre os porta-enxertos estudados.TĂtulo em portuguĂȘs: Desempenho de porta-enxertos clonais para pessegueiro 'BRS-Kampai'e autoenraizado em regiĂŁo de inverno ameno
Measurement of the front-end dead-time of the LHCb muon detector and evaluation of its contribution to the muon detection inefficiency
A method is described which allows to deduce the dead-time of the front-end
electronics of the LHCb muon detector from a series of measurements performed
at different luminosities at a bunch-crossing rate of 20 MHz. The measured
values of the dead-time range from 70 ns to 100 ns. These results allow to
estimate the performance of the muon detector at the future bunch-crossing rate
of 40 MHz and at higher luminosity
Intermediate-mass dilepton spectra and the role of secondary hadronic processes in heavy-ion collisions
We carry out a study of intermediate-mass (between 1 and 2.5 GeV) dilepton
spectra from hadronic interactions in heavy-ion collisions. The processes
considered are , , , , , and . The elementary cross sections for those are obtained
from chiral Lagrangians involving pseudoscalar, vector, and axial-vector
mesons. The respective electromagnetic form factors are determined by fitting
to experimental data for the reverse processes of . Based on
this input we calculate cross sections and thermal dilepton emission rates and
compare our results with those from other approaches. Finally we use these
elementary cross sections with a relativistic transport model and calculate
dilepton spectra in S+W collisions at SPS energies. The comparison of our
results with experimental data from the HELIOS-3 collaboration indicates the
importance of the secondary hadronic contributions to the intermediate-mass
dilepton spectra.Comment: 25 pages, including 20 postscript figure
Performance of the LHCb muon system with cosmic rays
The LHCb Muon system performance is presented using cosmic ray events
collected in 2009. These events allowed to test and optimize the detector
configuration before the LHC start. The space and time alignment and the
measurement of chamber efficiency, time resolution and cluster size are
described in detail. The results are in agreement with the expected detector
performance.Comment: Submitted to JINST and accepte
Measurement of the kinematic variables of beauty particles produced in 350 GeV/c -Cu interactions
Using a sample of b\=b events, produced in interactions in a copper target, which includes events where the decays of both and are well reconstructed, we measure the differential distributions with respect to and as well as some two-particle kinematic variables. We also compare our results with a previous experiment and with predictions based on perturbative QCD
Performance of the LHCb muon system
The performance of the LHCb Muon system and its stability across the full
2010 data taking with LHC running at ps = 7 TeV energy is studied. The
optimization of the detector setting and the time calibration performed with
the first collisions delivered by LHC is described. Particle rates, measured
for the wide range of luminosities and beam operation conditions experienced
during the run, are compared with the values expected from simulation. The
space and time alignment of the detectors, chamber efficiency, time resolution
and cluster size are evaluated. The detector performance is found to be as
expected from specifications or better. Notably the overall efficiency is well
above the design requirementsComment: JINST_015P_1112 201
Azimuthal correlation between beauty particles produced in 350 GeV/c -Cu interactions
Using a sample of triggered events, produced in interactions in a copper target, we have identified b\=b events. These include events where the decays of both and are well reconstructed. We measure the azimuthal \hbox{correlation} between beauty particles, and compare our result with predictions based on perturbative QCD
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