4,869 research outputs found
Production of b-carotene, a-carotene and lutein nanocapsules by interfacial deposition of preformed polymers.
The objective of this study was the production of carotenoids (b-carotene, a-carotene and lutein) nanocapsules and their characterization during a 90 days period of cold storage at 4 °C
Efeito da adubação nitrogenada no algodoeiro em sistema integrado lavoura-pecuária e plantio direto.
Agronomic performance of interspecific Paspalum hybrids under nitrogen fertilization or mixed with legumes
Nitrogen supply and mixtures with legumes affect agronomic performance of pas- tures, and both practices can guide breeding decisions in Paspalum hybrids. The goals of this study were: (a) quantify herbage accumulation (HA), leaf accumulation (LA), cold tolerance, and N use efficiency (NUE) in P. plicatulum × P. guenoarum hybrids subjected to N fertilization or grown in a mixture with legumes; (b) compare the grass–legume system to a grass–N fertilizer system; and (c) select the best hybrid for future cultivar releases. A randomized complete block design with three repli- cations and a split-plot treatment arrangement was used for 2 yr, with five N rates (0, 60, 120, 240, and 480 kg N ha−1) and a grass–legume mixture [grass + white clover (Trifolium repens L.) + birdsfoot trefoil (Lotus corniculatus L.)] as whole plots, and six genotypes as subplots (hybrids: 1020133, 102069, 103084, 103061; and controls: P. guenoarum ‘Azulão’ and Megathyrsus maximus ‘Aruana’). Higher N rates increased HA, LA, and cold tolerance. Higher NUE was obtained between 60 and 120 kg N ha−1. In the grass–legume mixture HA was similar to the rates of 60 and 120 kg N ha−1. Hybrid 1020133 had HA similar to the controls, LA greater than Aruana, and greater cold tolerance and NUE at 60 kg N ha−1 than Azulão and Aruana. Hybrid 1020133 should be selected for further animal performance stud- ies. The agronomic performance of perennial pastures can be improved through N management, and NUE should be a selection criterion in forage breeding
Estudo da germinação e morfologia do desenvolvimento pós-seminal de Syngonanthus mucugensis Giul. “in vitro”
Syngonanthus mucugensis (Eriocaulaceae) grows in the “rupestres” fields of Bahia. Its economic importance rests in the use of both the stem and flowers in crafts, making extractivism an important economic activity within its distribution. Indiscriminate collecting is threatening populations of the species. This study sought to evaluate germination and post-seminal development of S. mucugensis in vitro, seeking to supply information for future works. After asepsis and water uptake for 24 hours, the seeds were placed to germinate in petri dishes under controlled conditions of light and darkness. In each petri dish, 20 seeds were placed on a culture mediun for germination (agar 7 g.L-1), with pH 5.7 adjusted prior to autoclaving (1 atm, 121ºC and 15 min). The results showed that the seeds of S. mucugensis need light to germinate, the germination is of the hypogeal type with success rate of 85%. The first phase of the post-seminal development begins with the protrusion of the embryonic axis from which the leaves and the radicular system are simultaneously developed. Approximately 25 days after the germination, the plants presented average length of 10 mm, about four leaves with malphigiaceous tricomes distributed along the margins and a radicular system consisting of two roots.Syngonanthus mucugensis (Eriocaulaceae) ocorre nos campos rupestres da Bahia. Sua importância econômica reside no uso em artesanatos das inflorescências e escapos. Isso confere a essa espécie alto valor comercial e o seu extrativismo constitui-se em uma importante atividade econômica nas regiões onde ocorre. A exploração tem sido feita de forma indiscriminada, o que expõe a espécie ao risco de extinção. O objetivo do presente trabalho foi avaliar as principais características da germinação e analisar a morfologia do desenvolvimento pós-seminal de S. mucugensis in vitro, visando fornecer subsídios para futuros trabalhos. Após assepsia e tratamento de embebição por 24 horas, as sementes foram colocadas para germinar em placas de Petri sob condições controladas no claro ou no escuro. Foram utilizadas 20 sementes em cada placa de Petri, contendo meio de cultura para germinação (7 g.L-1 de ágar), com pH 5,7 ajustado antes da autoclavagem (1 atm, 121 ºC e 15 min). Os resultados mostraram que sementes de S. mucugensis necessitam de luz para germinar, a germinação é do tipo hipógea com taxa superior a 85%, ocorrendo um embrião por semente. A primeira fase do desenvolvimento pósseminal inicia-se com a protrusão do eixo embrionário de onde se desenvolvem concomitantemente as folhas e as raízes. Aproximadamente 25 dias após a germinação, as plantas apresentaram comprimento médio de 10 mm, cerca de quatro folhas com tricomas malphighiáceos distribuídos pelas margens e um sistema radicular formado por duas raízes
Opposite-side flavour tagging of B mesons at the LHCb experiment
The calibration and performance of the oppositeside
flavour tagging algorithms used for the measurements
of time-dependent asymmetries at the LHCb experiment
are described. The algorithms have been developed using
simulated events and optimized and calibrated with
B
+ →J/ψK
+, B0 →J/ψK
∗0 and B0 →D
∗−
μ
+
νμ decay
modes with 0.37 fb−1 of data collected in pp collisions
at
√
s = 7 TeV during the 2011 physics run. The oppositeside
tagging power is determined in the B
+ → J/ψK
+
channel to be (2.10 ± 0.08 ± 0.24) %, where the first uncertainty
is statistical and the second is systematic
Measurement of the ratio of branching fractions BR(B0 -> K*0 gamma)/BR(Bs0 -> phi gamma)
The ratio of branching fractions of the radiative B decays B0 -> K*0 gamma
and Bs0 -> phi gamma has been measured using 0.37 fb-1 of pp collisions at a
centre of mass energy of sqrt(s) = 7 TeV, collected by the LHCb experiment. The
value obtained is BR(B0 -> K*0 gamma)/BR(Bs0 -> phi gamma) = 1.12 +/- 0.08
^{+0.06}_{-0.04} ^{+0.09}_{-0.08}, where the first uncertainty is statistical,
the second systematic and the third is associated to the ratio of fragmentation
fractions fs/fd. Using the world average for BR(B0 -> K*0 gamma) = (4.33 +/-
0.15) x 10^{-5}, the branching fraction BR(Bs0 -> phi gamma) is measured to be
(3.9 +/- 0.5) x 10^{-5}, which is the most precise measurement to date.Comment: 15 pages, 1 figure, 2 table
Differential branching fraction and angular analysis of the decay B0→K∗0μ+μ−
The angular distribution and differential branching fraction of the decay B 0→ K ∗0 μ + μ − are studied using a data sample, collected by the LHCb experiment in pp collisions at s√=7 TeV, corresponding to an integrated luminosity of 1.0 fb−1. Several angular observables are measured in bins of the dimuon invariant mass squared, q 2. A first measurement of the zero-crossing point of the forward-backward asymmetry of the dimuon system is also presented. The zero-crossing point is measured to be q20=4.9±0.9GeV2/c4 , where the uncertainty is the sum of statistical and systematic uncertainties. The results are consistent with the Standard Model predictions
Search for CP violation in decays
A model-independent search for direct CP violation in the Cabibbo suppressed
decay in a sample of approximately 370,000 decays is
carried out. The data were collected by the LHCb experiment in 2010 and
correspond to an integrated luminosity of 35 pb. The normalized Dalitz
plot distributions for and are compared using four different
binning schemes that are sensitive to different manifestations of CP violation.
No evidence for CP asymmetry is found.Comment: 13 pages, 8 figures, submitted to Phys. Rev.
Observation of two new baryon resonances
Two structures are observed close to the kinematic threshold in the mass spectrum in a sample of proton-proton collision data, corresponding
to an integrated luminosity of 3.0 fb recorded by the LHCb experiment.
In the quark model, two baryonic resonances with quark content are
expected in this mass region: the spin-parity and
states, denoted and .
Interpreting the structures as these resonances, we measure the mass
differences and the width of the heavier state to be
MeV,
MeV,
MeV, where the first and second
uncertainties are statistical and systematic, respectively. The width of the
lighter state is consistent with zero, and we place an upper limit of
MeV at 95% confidence level. Relative
production rates of these states are also reported.Comment: 17 pages, 2 figure
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