Nonforward parton distributions of the pion within an effective single instanton approximation

We develop a relativistic quark model for pion structure, which incorporates the nontrivial structure of the vacuum of quantum chromodynamics as modelled by instantons. Pions are bound states of quarks and the strong quark-pion vertex is determined from an instanton induced effective Lagrangian. The interaction of the constituents of the pion with the external electromagnetic field is introduced in gauge invariant form. The parameters of the model, i.e., effective instanton radius and constituent quark mass, are obtained from the vacuum expectation values of the lowest dimensional quark and gluon operators and the low-energy observables of the pion. We apply the formalism to the calculation of the pion form factor by means of the isovector nonforward parton distributions and find agreement with the experimental data. © 2000 Elsevier Science B.V.

Necessidade Hídrica E Coeficiente de Cultivo do Pimentão Fertirrigado

This study aimed to determine the crop evapotranspiration (ETc) and crop coefficient (Kc) of fertigated sweet pepper, measured over time (15, 30, 45, 60, 75, 90 and 105 days after the transplant). The experiment was conducted on a battery of 40 drainage lysimeters, arranged in a 8 x 5 matrix, in the period October/2009 to January/2010, located in the Federal Rural University of Pernambuco (UFRPE) Campus in Recife, in a completely randomized factorial scheme 5 x 2, with four replications, being five irrigation depths (80, 90, 100, 110 and 120% of ETc) and two levels of potassium (80 and 120 kg K2O ha-1) where the experimental plot was composed of three plants in each lysimeter. The Mauchly Sphericity Test indicated multivariate variance analysis for the studied variables ETc (mm d-1) and Kc, the variables presented adjustment under quadratic effect of variation on observation times, when the irrigation depths were fixed, and descending linear adjustments under the variation of irrigation depths effect, when the times of observation were fixed in each potassium dose.

High-voltage electrophoretic deposition of preferentially oriented films from multiferroic YMn2O5 nanopowders

Processing of the YMn2O5 powder is very challenging, since it decomposes to YMnO3 and Mn3O4 at temperatures close to 1180 °C, while samples consolidation commonly demands high temperatures. The main goal of this work is to investigate a possibility to prepare thick films of YMn2O5, since their deposition generally requires significantly lower temperatures. Multiferroic YMn 2O5 was synthesized by the hydrothermal method from Y(CH3COO)3·xH2O, Mn(CH 3COO)2·4H2O and KMnO4 precursors. XRD, FE-SEM and TEM analysis showed that the obtained powder was monophasic, with orthorhombic crystal structure and columnar particle shape with mean diameter and length of around 20 and 50 nm, respectively. The obtained powder was suspended in isopropyl alcohol with addition of appropriate binder and deflocculant. This suspension was used for electrophoretic deposition of YMn2O5 thick films under the high-voltage conditions and electric fields ranging from 250 to 2125 V/cm. The films obtained at 1000 V/cm and higher electric fields showed good adhesion, particle packing, homogeneity and very low porosity. It was shown that the deposition in extremely high electric fields (KC=2125 V/cm) can influence the crystal orientation of the films, resulting in formation of preferentially oriented films. © 2012 Elsevier Ltd and Techna Group S.r.l.

Coeficientes de cultura para a melancieira irrigada por gotejamento no Vale do Gurgueia - PI

The aim of this work was to determine crop coefficients (Kc) of drip irrigated watermelon in the climatic and growing conditions of the Gurgueia Vale, State of Piaui, Brazil, located at 8 ° 26' S, 43 ° 47' W and altitude of 251 m. The reference evapotranspiration (ET0) was determined by the sum of hourly values of ET0 obtained by the Penman-Monteith method parameterized by FAO with climatic data obtained from an automatic weather station. The daily crop evapotranspiration (ETc) was measured by three weighing lysimeters of load cells. Aiming high fruit yield in this region, we recommend that the following local values of Kc and Kcb be used for planning and management of irrigation, respectively: initial stage (crop establishment) - 0.34 and 0.24; intermediate stage (growth and fruit maturation) - 1.16 and 1.10; end stage (harvest) - 0.93 and 0.86. These Kc values of initial and intermediate phases are statistically higher than the values of Kc and Kcb already adjusted according to the methodology presented in the FAO Irrigation and Drainage Paper 56. The values of Kc and Kcb at the end phase are not statistically different from the FAO values.

Caracterização do saldo de radiação em ambiente protegido e a campo de seus efeitos sobre as necessidades hídricas do cravo-de-defunto (Tagetes sp.)

Pós-graduação em Agronomia (Energia na Agricultura) - FCA

Influência de manejo de irrigação sobre aspectos da ecofisiologia e produção da videira CV. Syrah

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Desenvolvimento de plantas de sorgo submetidas a diferentes níveis de lençol freático

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Irrigação deficitária em videira de vinho cv. Syrah durante o período chuvoso no semiárido

Pós-graduação em Agronomia (Irrigação e Drenagem) - FCA

Fractografia quantitativa: relações entre tenacidade e o comportamento fractal em ligas metálicas

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Estudo dos mecanismos envolvidos na migração celular induzida pelo hidróxido de cálcio para bolha de ar subcutânea em camundongos

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Estudo dos mecanismos envolvidos na resposta tecidual de camundongos diabéticos com doença periodontal: papel dos mastócitos

Pós-graduação em Ciência Odontólogica - FOA

Temperatura superficial e interna de cimentos de ionômeros de vidro e transmissão à câmara pulpar: aplicação de ondas de ultrassom

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Interação entre as substâncias húmicas de sedimentos e metais potencialmente tóxicos: um estudo na Bacia Hidrográfica do Turvo/Grande

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Comportamento de cultivares de arroz de terras altas em função do preparo do solo e irrigação por aspersão, em latossolo vermelho de cerrado

Pós-graduação em Agronomia - FEIS

Resposta imune induzida pelas peçonhas do bagre Cathorops agassizii

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)