Yield and incidence of hollow stem disorder of cauliflower 'Sharon' influenced by the application of nitrogen and boron

A podridão parda é um problema comum em couve-flor que ocasiona sintoma semelhante ao da deficiência de B. Sua ocorrência está associada, especialmente, às adubações com nitrogênio e boro, mas há escassez de informações sobre o problema no Brasil. Neste trabalho avaliou-se o efeito de doses de nitrogênio e épocas de aplicação de boro na produção e na incidência de podridão parda da couve-flor 'Sharon'. O experimento foi realizado em Argissolo Vermelho Amarelo de novembro/2005 a fevereiro/2006, com quatro doses de N (100; 150; 200 e 250 kg ha-1) e duas épocas de aplicação de 3 kg ha-1 B (1 e 2 aplicações), além do controle (sem aplicação). O diâmetro das cabeças e a produtividade comercial variaram de 16,45 a 22,03 cm e 15,71 a 29 t ha-1, respectivamente, e não foram influenciados pelos tratamentos. As doses de N proporcionaram aumento linear no teor nas folhas e nas cabeças. O caule oco e bronzeamento das cabeças foram reduzidos, enquanto a produtividade comercial aumentou com aplicação de B. Houve correlação negativa entre o teor de B nas folhas (r=0,66; p<0,05) e nas cabeças (r=0,76; p<0,05) e a incidência de caule oco. A adubação com B para a couve-flor cultivada em solo com teor médio (0,54 mg de B dm-3) é necessária para reduzir os sintomas da podridão parda. Contudo, mais estudos são necessários em outros solos e cultivares para redução desse distúrbio fisiológico em condições tropicais e melhoria da eficiência da adubação com boro.The hollow stem disorder is a common problem in cauliflower, resulting in similar symptoms as those caused by B deficiency. Its occurrence in cauliflower is related to nitrogen and boron levels. There exist little information about this subject in Brazil. The effect of nitrogen rates and boron application periods were evaluated on the cauliflower production and incidence of hollow stem. The experiment was carried out from November 2005 through February 2006 in a Kandiustalf soil (0.54 mg B kg-1, BaCl2 1.25 mg L-1) at Tietê region, São Paulo State, Brazil, in a randomized complete block design with four replicates, four N levels (100; 150; 200 and 250 kg ha-1) and two periods of B application (one and two applications) and a control (without application). Cauliflower curd diameter ranged from 16.45 to 22.03 cm and the commercial yield from 15.71 to 29 t ha-1; these two traits were not influenced by treatments. Nitrogen rates increased linearly in leaves and curds. The hollow stem and curd browning were reduced and commercial yield was increased with B fertilization. The correlation between B concentration on leaves (r= 0.66; p<0.05) and curds (r= 0.76; p<0.05) with hollow stem disorder was negative. Boron fertilization is necessary to reduce the symptoms of hollow stem when cauliflower is grow in soil with medium B level (0.54 mg B dm-3). More studies are needed using other types of soil and other cauliflower cultivars in order to reduce this physiological disorder in tropical conditions and increase the efficiency of boron fertilization

Standalone vertex finding in the ATLAS muon spectrometer

A dedicated reconstruction algorithm to find decay vertices in the ATLAS muon spectrometer is presented. The algorithm searches the region just upstream of or inside the muon spectrometer volume for multi-particle vertices that originate from the decay of particles with long decay paths. The performance of the algorithm is evaluated using both a sample of simulated Higgs boson events, in which the Higgs boson decays to long-lived neutral particles that in turn decay to bbar b final states, and pp collision data at √s = 7 TeV collected with the ATLAS detector at the LHC during 2011

Measurements of Higgs boson production and couplings in diboson final states with the ATLAS detector at the LHC

Measurements are presented of production properties and couplings of the recently discovered Higgs boson using the decays into boson pairs, H →γ γ, H → Z Z∗ →4l and H →W W∗ →lνlν. The results are based on the complete pp collision data sample recorded by the ATLAS experiment at the CERN Large Hadron Collider at centre-of-mass energies of √s = 7 TeV and √s = 8 TeV, corresponding to an integrated luminosity of about 25 fb−1. Evidence for Higgs boson production through vector-boson fusion is reported. Results of combined fits probing Higgs boson couplings to fermions and bosons, as well as anomalous contributions to loop-induced production and decay modes, are presented. All measurements are consistent with expectations for the Standard Model Higgs boson

Expected Performance of the ATLAS Experiment - Detector, Trigger and Physics

A detailed study is presented of the expected performance of the ATLAS detector. The reconstruction of tracks, leptons, photons, missing energy and jets is investigated, together with the performance of b-tagging and the trigger. The physics potential for a variety of interesting physics processes, within the Standard Model and beyond, is examined. The study comprises a series of notes based on simulations of the detector and physics processes, with particular emphasis given to the data expected from the first years of operation of the LHC at CERN

Measurement of the top quark pair cross section with ATLAS in pp collisions at √s=7 TeV using final states with an electron or a muon and a hadronically decaying τ lepton

A measurement of the cross section of top quark pair production in proton-proton collisions recorded with the ATLAS detector at the Large Hadron Collider at a centre-of-mass energy of 7 TeV is reported. The data sample used corresponds to an integrated luminosity of 2.05 fb -1. Events with an isolated electron or muon and a τ lepton decaying hadronically are used. In addition, a large missing transverse momentum and two or more energetic jets are required. At least one of the jets must be identified as originating from a b quark. The measured cross section, σtt-=186±13(stat.)±20(syst.)±7(lumi.) pb, is in good agreement with the Standard Model prediction

Measurement of the top quark-pair production cross section with ATLAS in pp collisions at \sqrt{s}=7\TeV

A measurement of the production cross-section for top quark pairs(\ttbar) in $pp$ collisions at \sqrt{s}=7 \TeV is presented using data recorded with the ATLAS detector at the Large Hadron Collider. Events are selected in two different topologies: single lepton (electron $e$ or muon $\mu$) with large missing transverse energy and at least four jets, and dilepton ($ee$, $\mu\mu$ or $e\mu$) with large missing transverse energy and at least two jets. In a data sample of 2.9 pb-1, 37 candidate events are observed in the single-lepton topology and 9 events in the dilepton topology. The corresponding expected backgrounds from non-\ttbar Standard Model processes are estimated using data-driven methods and determined to be $12.2 \pm 3.9$ events and $2.5 \pm 0.6$ events, respectively. The kinematic properties of the selected events are consistent with SM \ttbar production. The inclusive top quark pair production cross-section is measured to be \sigmattbar=145 \pm 31 ^{+42}_{-27} pb where the first uncertainty is statistical and the second systematic. The measurement agrees with perturbative QCD calculations.Comment: 30 pages plus author list (50 pages total), 9 figures, 11 tables, CERN-PH number and final journal adde

Hunt for new phenomena using large jet multiplicities and missing transverse momentum with ATLAS in 4.7 fb−1 of √s=7 TeV proton-proton collisions

Results are presented of a search for new particles decaying to large numbers of jets in association with missing transverse momentum, using 4.7 fb−1 of pp collision data at s√=7TeV collected by the ATLAS experiment at the Large Hadron Collider in 2011. The event selection requires missing transverse momentum, no isolated electrons or muons, and from ≥6 to ≥9 jets. No evidence is found for physics beyond the Standard Model. The results are interpreted in the context of a MSUGRA/CMSSM supersymmetric model, where, for large universal scalar mass m 0, gluino masses smaller than 840 GeV are excluded at the 95% confidence level, extending previously published limits. Within a simplified model containing only a gluino octet and a neutralino, gluino masses smaller than 870 GeV are similarly excluded for neutralino masses below 100 GeV