242 research outputs found
Deposit of pesticides without and with adjuvants on citrus seedlings following different intervals of artificial rain
Photosynthesis, stomatal conductance and leaf water potential in crabwood (Carapa guianensis)
Leaf water potential is one of the most important factors affecting stomatal functioning. The aim of this study was to assess the effect of variation in diurnal irradiance and vapour pressure deficit on photosynthesis (A), stomatal conductance (g s) and leaf water potential (psi) in Carapa guianensis (Aubl.). Data were collected from 07:00 to 17:00 h. Photosynthetic rates reached a maximum (2.5 Âľmol m-2 s-1) at 10:00 h, thereafter declined to a minimum of 1 Âľmol m-2 s-1 at 16:00 h. Stomatal conductance oscillated during the day, from 0.04 mol m-2 s-1 (at midday) to 0.02.mol.m-2.s-1 at the end of the afternoon. Leaf water potential was higher early in the morning (-0.3 MPa) and lower (-0.75 MPa) at mid-afternoon (14:30 -15:00 h). After reaching a minimum, psi increased up to -0.64 MPa at sunset. Photosynthetic rates increased linearly as a function of g s (P < 0.01). Also there was a positive relationship between psi and g s (P< 0.01). Photosynthetic rates declined during the day after reaching a peak early in the morning, which makes clear that environmental factors that influence psi greatly affect carbon assimilation of C. guianensis.O potencial hĂdrico da folha ĂŠ um dos fatores mais importantes que afetam o funcionamento dos estĂ´matos. O objetivo deste trabalho foi avaliar o efeito da variação diurna na irradiância e dĂŠficit de pressĂŁo de vapor (DPV) na fotossĂntese (A), condutância estomĂĄtica (g s) e potencial hĂdrico da folha (psi) em Carapa guianensis (Aubl.). Os dados foram coletados de 07:00 Ă s 17:00 h. A taxa fotossintĂŠtica atingiu um valor mĂĄximo (2,5 Âľmol m-2 s-1) Ă s 10:00 h, depois declinou atĂŠ atingir um mĂnimo de 1 Âľmolm-2 s-1 Ă s 16:00 h. A condutância estomĂĄtica oscilou durante o dia, de 0,04 molm-2s-1 (ao meio dia) para 0,02 molm-2s- 1 no final da tarde. O potencial hĂdrico da folha foi mĂĄximo nas primeiras horas do dia (-0,3 MPa) e mĂnimo (-0,75 MPa) no meio da tarde (14:30 a 15:00 h). ApĂłs ter alcançado um mĂnimo, o psi aumentou atĂŠ -0,64 MPa no fim da tarde. A taxa fotossintĂŠtica aumentou linearmente em função do g s (P < 0,01). TambĂŠm houve uma relação positiva entre psi e g s (P < 0,01). A taxa fotossintĂŠtica declinou durante o dia apĂłs ter alcançado um pico no inĂcio da manhĂŁ, demonstrando que os fatores ambientais que afetam o psi tĂŞm efeito significativo na assimilação do carbono de C. guianensis
Faixas normais de nutrientes em cana-de-açúcar pelos mĂŠtodos ChM, DRIS e CND e nĂvel crĂtico pela distribuição normal reduzida
Existem diversos mĂŠtodos para a interpretação da diagnose foliar; o nĂvel crĂtico ou as faixas de suficiĂŞncia descritas na literatura sĂŁo os mais utilizados. PorĂŠm, o uso de mĂŠtodos de determinação de faixas normais de nutrientes que contemplam regiĂľes especĂficas (localidades) aumenta a eficiĂŞncia da interpretação. O objetivo deste trabalho foi determinar as faixas normais de nutrientes para a cultura da cana-de-açúcar, mediante a utilização dos mĂŠtodos Chance MatemĂĄtica (ChM), Sistema Integrado de Diagnose e Recomendação (DRIS) e Diagnose da Composição Nutricional (CND), alĂŠm do NĂvel CrĂtico determinado pelo mĂŠtodo de distribuição normal reduzida. O trabalho foi realizado tomando-se como base dados relativos a teores de nutrientes em amostras foliares e de produtividade de lavouras comerciais de cana-de-açúcar, localizadas no municĂpio de Campos de Goytacazes, RJ. Com o mĂŠtodo da ChM, foram obtidas faixas de suficiĂŞncia semelhantes aos mĂŠtodos DRIS e CND, para N, Ca, S e Mn, enquanto para P, K, Mg, Cu e Zn os valores obtidos pela ChM foram superiores. A utilização dos mĂŠtodos ChM, DRIS e CND, em lavouras comerciais de cana-de-açúcar em geral, possibilitou a obtenção de menor amplitude da faixa normal dos nutrientes, em comparação com os valores alcançados pelos mĂŠtodos nĂvel crĂtico e faixa de suficiĂŞncia
Propriedades mecânicas e microestruturais de juntas soldadas do aço HY-80 pelos processos eletrodo revestido e GMAW
Nitrogen fertilization (15NH4NO3) of palisadegrass and residual effect on subsequent no-tillage corn
Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV
Results are presented from a search for a W' boson using a dataset
corresponding to 5.0 inverse femtobarns of integrated luminosity collected
during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV.
The W' boson is modeled as a heavy W boson, but different scenarios for the
couplings to fermions are considered, involving both left-handed and
right-handed chiral projections of the fermions, as well as an arbitrary
mixture of the two. The search is performed in the decay channel W' to t b,
leading to a final state signature with a single lepton (e, mu), missing
transverse energy, and jets, at least one of which is tagged as a b-jet. A W'
boson that couples to fermions with the same coupling constant as the W, but to
the right-handed rather than left-handed chiral projections, is excluded for
masses below 1.85 TeV at the 95% confidence level. For the first time using LHC
data, constraints on the W' gauge coupling for a set of left- and right-handed
coupling combinations have been placed. These results represent a significant
improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe
Search for the standard model Higgs boson decaying into two photons in pp collisions at sqrt(s)=7 TeV
A search for a Higgs boson decaying into two photons is described. The
analysis is performed using a dataset recorded by the CMS experiment at the LHC
from pp collisions at a centre-of-mass energy of 7 TeV, which corresponds to an
integrated luminosity of 4.8 inverse femtobarns. Limits are set on the cross
section of the standard model Higgs boson decaying to two photons. The expected
exclusion limit at 95% confidence level is between 1.4 and 2.4 times the
standard model cross section in the mass range between 110 and 150 GeV. The
analysis of the data excludes, at 95% confidence level, the standard model
Higgs boson decaying into two photons in the mass range 128 to 132 GeV. The
largest excess of events above the expected standard model background is
observed for a Higgs boson mass hypothesis of 124 GeV with a local significance
of 3.1 sigma. The global significance of observing an excess with a local
significance greater than 3.1 sigma anywhere in the search range 110-150 GeV is
estimated to be 1.8 sigma. More data are required to ascertain the origin of
this excess.Comment: Submitted to Physics Letters
Hemograma e bioquĂmica sĂŠrica auxiliar em bezerros mestiços neonatos e ocorrĂŞncia de enfermidades
Search for new physics in events with opposite-sign leptons, jets, and missing transverse energy in pp collisions at sqrt(s) = 7 TeV
A search is presented for physics beyond the standard model (BSM) in final
states with a pair of opposite-sign isolated leptons accompanied by jets and
missing transverse energy. The search uses LHC data recorded at a
center-of-mass energy sqrt(s) = 7 TeV with the CMS detector, corresponding to
an integrated luminosity of approximately 5 inverse femtobarns. Two
complementary search strategies are employed. The first probes models with a
specific dilepton production mechanism that leads to a characteristic kinematic
edge in the dilepton mass distribution. The second strategy probes models of
dilepton production with heavy, colored objects that decay to final states
including invisible particles, leading to very large hadronic activity and
missing transverse energy. No evidence for an event yield in excess of the
standard model expectations is found. Upper limits on the BSM contributions to
the signal regions are deduced from the results, which are used to exclude a
region of the parameter space of the constrained minimal supersymmetric
extension of the standard model. Additional information related to detector
efficiencies and response is provided to allow testing specific models of BSM
physics not considered in this paper.Comment: Replaced with published version. Added journal reference and DO
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